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Approval and Promulgation of Air Quality Implementation Plans; Montana; Billings/Laurel Sulfur Dioxide State Implementation Plan
Note: EPA no longer updates this information, but it may be useful as a reference or resource.
[Federal Register: May 2, 2002 (Volume 67, Number 85)]
[Rules and Regulations]
[Page 22167-22241]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr02my02-20]
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Environmental Protection Agency
40 CFR Part 52
[MT-001-0007, MT-001-0008, MT-001-0009 and MT-001-0010; FRL-7175-1]
Approval and Promulgation of Air Quality Implementation Plans;
Montana; Billings/Laurel Sulfur Dioxide State Implementation Plan
AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.
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SUMMARY: EPA is partially approving and partially disapproving the
Billings/Laurel sulfur dioxide (SO2) State Implementation Plan (SIP)
revisions submitted by the State of Montana in response to a SIP Call.
EPA is also limitedly approving and limitedly disapproving one
provision of the SIP revisions. The SIP revisions establish, and
require seven sources to meet and monitor compliance with, SO2 emission
limitations and other requirements in the Billings/Laurel area. The
intended effect of this action is to make federally enforceable those
provisions that EPA is approving and to disapprove those provisions
that do not meet applicable requirements. EPA is taking this action
under sections 110 and 179 of the Clean Air Act (Act). In a separate
action being published today, EPA is proposing action on other
provisions of the Billings/Laurel SO2 SIP.
EFFECTIVE DATE: This final rule is effective June 3, 2002.
ADDRESSES: Copies of the documents relevant to this action are
available for public inspection during normal business hours at the Air
and Radiation Program, Environmental Protection Agency, Region 8, 999
18th Street, Suite 300, Denver, Colorado, 80202 and copies of the
Incorporation by Reference material at the Air and Radiation Docket and
Information Center, Environmental Protection Agency, 401 M Street, SW,
Washington, DC 20460. Copies of the State documents relevant to this
action are available for public inspection at the Montana Department of
Environmental Quality, Air and Waste Management Bureau, 1520 E. 6th
Avenue, Helena, Montana 59620.
FOR FURTHER INFORMATION CONTACT: Laurie Ostrand, EPA, Region 8, (303)
312-6437.
SUPPLEMENTARY INFORMATION:
Table of Contents
Definitions
I. Summary of EPA's Final Action
II. EPA's Action on the State of Montana's Submittals
A. Why Is EPA Approving Parts of the State of Montana's Plan?
B. Why Is EPA Disapproving Parts of the State of Montana's Plan?
C. Why Is EPA Proposing Action on Parts of the State of
Montana's Plan?
D. What Happens When EPA Approves Parts of the State of
Montana's Plan?
E. What Happens When EPA Disapproves Parts of the State of
Montana's Plan?
F. What Happens When EPA Limitedly Approves and Limitedly
Disapproves Parts of the State of Montana's Plan?
III. Other Issues Pertaining to State Authority
A. How Do the State-Only Provisions Affect EPA's Actions?
B. How Does Montana's Environmental Audit Act Affect EPA's
Actions?
IV. Other Rulemaking Actions
A. How Does This Final Action Relate to EPA's SIP Call?
B. Why Is EPA Not Imposing Sanctions?
V. What Comments Were Received on EPA's Proposed Action and How Is
EPA Responding to Those Comments?
VI. Administrative Requirements
Definitions
For the purpose of this document, we are giving meaning to certain
words or initials as follows:
(i) The words or initials Act or CAA mean or refer to the Clean Air
Act, unless the context indicates otherwise.
(ii) The initials CEMS mean or refer to continuous emission
monitoring systems.
(iii) The words EPA, we, us or our mean or refer to the United
States Environmental Protection Agency.
(iv) The initials FIP mean or refer to Federal Implementation Plan.
(v) The initials MBER mean or refer to the Montana Board of
Environmental Review.
(vi) The initials MDEQ mean or refer to the Montana Department of
Environmental Quality.
(vii) The initials MSCC mean or refer to the Montana Sulphur &
Chemical Company.
(viii) The initials NAAQS mean or refer to the national ambient air
quality standards.
(ix) The initials SIP mean or refer to the State Implementation
Plan.
(x) The initials SO2 mean or refer to sulfur dioxide.
(xi) The words State or Montana mean the State of Montana, unless
the context indicates otherwise.
(xii) The initials TSD mean or refer to the Technical Support
Document.
(xiii) The initials YELP mean or refer to the Yellowstone Energy
Limited Partnership.
I. Summary of EPA's Final Action
Apart from those provisions we are disapproving, limitedly
approving/limitedly disapproving, proposing to act on in a separate
action published today (see discussion below), or not acting on, we are
approving all other aspects of the Billings/Laurel SO2 SIP, which the
State of Montana submitted in response to our SIP Call. See Background
section V.D. in our proposed rulemaking action published on July 28,
1999 (64 FR 40791) for a discussion of the SIP Call. Our approval is
based on several interpretations of provisions of the SIP. The
interpretations described in our proposed approval still apply except
that, based on comments received, we have revised the interpretation of
``low sulfur fuel gas.'' See section V.Q. below. We caution that if we
find it too difficult to enforce certain variable (or pro-rated)
emission limitations at several of the sources or if data are not
available to determine the emission limitations on a regular basis, we
will reconsider our approval. Also, if we determine that the State-only
provisions, as implemented, appear to limit or constrain or otherwise
have a chilling effect on the Montana Department of Environmental
Quality's (MDEQ's) enforcement of the SIP, we will reconsider our
approval or take other appropriate action under the Act. Our
reconsideration could occur under section 110(k)(6) of the Act or we
could complete another SIP Call under sections 110(a)(2)(H) and
110(k)(5) of the Act. We caution that if sources are subject to more
stringent requirements under other provisions of the Act (e.g., section
111 new source performance standards; Title I, part C prevention of
significant deterioration; or SIP-approved permit programs under Title
I, part A), our approval of the SIP (including emission limitations and
other requirements), would not excuse sources from meeting these other,
more stringent requirements. Also, our action on this SIP is not meant
to imply any sort of applicability determination under other provisions
of the Act (e.g., section 111; Title I, part C; or SIP-approved permit
programs under Title I, part A).
We are disapproving the following provisions of the Billings/Laurel
SO2 SIP \1\:
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\1\ The SIP was submitted in the form of orders, stipulations,
exhibits and attachments for each source covered by the plan. The
majority of the requirements are contained in the exhibits.
Throughout this document when we refer to an exhibit, we mean
exhibit A to the stipulation for the specified source.
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The escape clause (paragraph 22 in the ExxonMobil \2\ and
MSCC stipulations and paragraph 20 in the
[[Page 22169]]
Cenex, Conoco, Montana Power, Western Sugar and YELP stipulations).
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\2\ Between our July 28, 1999 proposal action and this action,
Exxon's name was changed to ExxonMobil. Our July 1999 proposal
simply referred to Exxon.
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The MSCC stack height credit and emission limitations on
the sulfur recovery unit (SRU) 100-meter stack (paragraph 1 of the
ExxonMobil stipulation, paragraphs 1 and 2 of the MSCC stipulation, and
section 3(A)(1)(a) and (b) and 3(A)(3) of the MSCC exhibit).
The emission limitation on MSCC's auxiliary vent stacks,
section 3(A)(4) of MSCC's exhibit.
The attainment demonstration, because of improper stack
height credit and emission limitations at MSCC.
The attainment demonstration for lack of flare emission
limitations at Cenex, Conoco, ExxonMobil, and MSCC.
The attainment demonstration, because of the disapproval
of the emission limitation for MSCC's auxiliary vent stacks.
The Reasonably Available Control Measures (RACM)
(including Reasonably Available Control Technology (RACT)) and
Reasonable Further Progress (RFP) requirements for Cenex.
The provisions that allow sour water stripper emissions to
be burned in the flare at Cenex and ExxonMobil (the following phrase
from section 3(B)(2) of Cenex's exhibit A and section 3(E)(4) of
ExxonMobil's exhibit A: ``or in the flare''; the following phrases in
section 4(D) of Cenex's exhibit A and section 4(E) of ExxonMobil's
exhibit A: ``or in the flare'' and ``or the flare''. )
We are limitedly disapproving the following provision:
The emission limitation for the 30-meter stack at MSCC
(section 3(A)(2) of MSCC's exhibit A) because it lacks a reliable
compliance monitoring method.
We are not acting on the following provisions:
The provisions in section 6(B)(3) of MSCC's exhibit that
require certain monitoring equipment to support the variable emission
limitations.
In a separate action published today, we are proposing action on
the following provisions of the Billings/Laurel SO2 SIP submitted on
July 29, 1998 \3\:
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\3\ In our July 28, 1999 proposed action we proposed to
conditionally approve these provisions based on the Governor's
commitment to address concerns we had raised. The Governor submitted
a SIP revision on May 4, 2000 which was intended to fulfill the
commitments. Since the Governor has submitted a SIP revision to
fulfill the commitments, we are not finalizing our proposed
conditional approval and instead are proposing separate action on
parts of the July 29, 1998 submittal (i.e., those parts we proposed
to conditionally approve on July 28, 1999) and all of the May 4,
2000 submission (which is some cases modified the provisions of the
July 29, 1998 submittal).
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YELP's emission limitations (in section 3(A)(1) through
(3) of YELP's exhibit).
ExxonMobil's coker CO-boiler emission limitation (in
section 3(B)(1) of ExxonMobil's exhibit).
ExxonMobil's F-2 crude/vacuum heater stack emission
limitations and attendant compliance monitoring methods (specifically,
section 3(A)(2) of exhibit A; section 3(B)(3) of exhibit A; the
following phrase from section 3(E)(4) of exhibit A ``except that the
sour water stripper overheads may be burned in the F-1 Crude Furnace
(and exhausted through the F-2 Crude/Vacuum Heater stack) or in the
flare during periods when the FCC CO Boiler is unable to burn the sour
water stripper overheads, provided that: (a) such periods do not exceed
55 days per calendar year and 65 days for any two consecutive calendar
years, and (b) during such periods the sour water stripper system is
operating in a two tower configuration.''; section 4(E) of exhibit A;
and method #6A of attachment #2,\4\ of exhibit A).
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\4\ In our July 28, 1999 proposal action, we proposed to
conditionally approve all of attachment #2 of ExxonMobil's exhibit.
We should have limited our proposed conditional approal to only
method #6A of attachment #2 of ExxonMobil's exhibit.
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ExxonMobil's fuel gas combustion emission limitations and
attendant compliance monitoring methods (in sections 3(A)(1), 3(B)(2),
4(B), and 6(B)(3) of ExxonMobil's exhibit).
Cenex's combustion sources emission limitations and
attendant compliance monitoring methods (specifically, section
3(A)(1)(d) of exhibit A; the following phrase from section 3(B)(2) of
exhibit A ``except that those sour water stripper overheads may be
burned in the main crude heater (and exhausted through the main crude
heater stack) or in the flare during periods when the FCC CO boiler is
unable to burn the sour water stripper overheads from the ``old'' SWS,
provided that such periods do not exceed 55 days per calendar year and
65 days for any two consecutive calendar years.''; section 4(B) of
exhibit A; section 4(D) of exhibit A; and method #6A of attachment #2
\5\ of exhibit A).
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\5\ In our July 28, 1999 proposal action, we proposed to
conditionally approve all of attachment #2 of Cenex's exhibit. We
should have limited our proposed conditional approval to only method
#6A of attachment #2 of Cenex's exhibit.
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We have also revised the regulatory text from what was proposed.
The regulatory text appears at the end of this notice. The proposed
regulatory text started at 64 FR 40807 (July 28, 1999). As indicated
later in this notice, we are not selecting the order of sanctions as we
had proposed. Therefore, we are not including the regulatory text that
was proposed for 40 CFR 52.32(b). Also, we proposed to conditionally
approve several provisions of the SIP. Since we are not finalizing the
conditional approval of those provisions, and instead are proposing
action on them in a separate notice being published today, the
regulatory text at the end of this notice also excludes from the
incorporation by reference the provisions we proposed to conditionally
approve. See 40 CFR 52.1370(c)(46)(i)(A), (C) and (G). We also expanded
40 CFR 52.1370(c)(46)(i)(A) and (C) to explicitly indicate the phrases
not being incorporated by reference at this time. Additionally, based
on comments received, we are not acting on an additional provision of
MSCC's exhibit and excluding it from the incorporation by reference.
See 40 CFR 52.1370(c)(46)(i)(E). Finally, we added regulatory text at
the end of this notice to indicate those provisions of the stipulations
and/or exhibits that we are partially or limitedly disapproving. See 40
CFR 52.1384(d).
II. EPA's Action on the State of Montana's Submittals
A. Why Is EPA Approving Parts of the State of Montana's Plan?
On July 28, 1999 (64 FR 40791) we proposed to partially approve the
Billings/Laurel SO2 SIP. Our proposed rulemaking action discussed
several issues that we resolved with the State as well as
interpretations we made of several provisions in the Billings/Laurel
SO2 SIP. We have considered the comments received \6\ and still believe
we should partially approve the plan as proposed except that we are
limitedly approving/disapproving one provision of the SIP, the emission
limitation for the 30-meter stack at MSCC, that we had proposed to
partially approve.
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\6\ The comments received and our response to the comments are
discussed below in section V., entitled ``What Comments Were
Received on EPA's Proposed Action and How Is EPA Responding to Those
Comments?''
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Additionally, EPA believes partially and limitedly approving the
Billings/Laurel SO2 SIP meets the requirements of section 110(l) of the
Act. The approved provisions of the plan strengthen the Montana SIP by
providing specific control strategies and compliance determining
methods for SO2 sources in Billings/Laurel, Montana which further the
goals of and achieve progress toward attaining the SO2 NAAQS.
[[Page 22170]]
B. Why Is EPA Disapproving Parts of the State of Montana's Plan?
In our July 28, 1999 proposed rulemaking, we proposed to partially
disapprove portions of the Billings/Laurel SO2 SIP. We have considered
the comments received and still believe we should partially disapprove
the SIP as proposed. In addition, because of comments received we are
not acting on an additional provision of the SIP. See the discussion in
section II.B.2 below. Finally, because of comments received, we are
limitedly disapproving one provision of the SIP. See the discussion in
section II.B.6 below. The parts of the Plan we are disapproving follow:
1. Escape Clause
Each stipulation contains a paragraph which allows a source to
withdraw its consent to the stipulation. The ``escape clause'' is
printed in full in our July 28, 1999 proposed rulemaking action (see
right column of 64 FR 40797).
We are disapproving the escape clause because, if sources invoke
the escape clause, the MDEQ will no longer have a plan to implement.
Specifically, we are disapproving the following: paragraph 22 in the
ExxonMobil and MSCC stipulations; paragraph 20 in the Cenex, Conoco,
Montana Power, Western Sugar and YELP stipulations. If sources invoke
the escape clause after our final action on the SIP, we expect to
respond by issuing another SIP Call under sections 110(a)(2)(H) and
110(k)(5) of the Act or taking other appropriate action under the Act.
Additionally, with the disapproval of the escape clause, the provisions
of the SIP that we approve will remain federally enforceable even if
one or more of the sources invoke the escape clause. While our
disapproval of the escape clause eliminates the risk of a source's
future attempt to nullify the SIP, we do not believe our disapproval
renders the SIP more stringent than the State of Montana intends,
because our disapproval does not change the stringency of any of the
substantive requirements the State of Montana has imposed and is
currently able to enforce under the SIP. Moreover, a source's exercise
of the escape clause would not represent the State's decision to
suspend its own SIP or constitute any decision on the part of the State
to change the SIP's enforceable requirements. Finally, since the escape
clause is a provision that EPA could not lawfully approve under title I
of the CAA, the only alternative to EPA's partial disapproval would be
a total disapproval of the SIP, which we believe the State would not
favor over today's action.
2. MSCC Stack Height Credit and Emission Limitations on the Sulfur
Recovery Unit (SRU) 100-Meter Stack
We are disapproving MSCC's SRU 100-meter stack height credit and
emission limitations (paragraph 2 of the MSCC stipulation and sections
3(A)(1)(a) and (b) and 3(A)(3) of the MSCC exhibit) used in the
attainment demonstration modeling for the Billings/Laurel area. We
believe it is necessary to disapprove MSCC's emission limitations
because the State of Montana has set limitations based on an amount of
stack height credit for MSCC that is not supportable under section 123
of the Act or our stack height regulations.
Our July 28, 1999 proposed rulemaking action (starting in the left
column of 64 FR 40798), and TSD to that proposal, discuss the Act's
stack height requirements (see those documents for the complete
discussion).
Additionally, because of comments received we are not acting on the
monitoring provisions in section 6(B)(3) of MSCC's exhibit. Since we
are disapproving MSCC's variable emission limitation, we believe it
does not make sense to approve section 6(B)(3) of MSCC's exhibit, which
requires MSCC to install certain monitoring equipment to support the
use of the variable limitation. Section 6(B)(3) would be needed only if
we were approving MSCC's variable emissions limitation.
3. Language in ExxonMobil and MSCC's Stipulations Related to
Incorporation of Earlier Stipulations and Apportionment of the Airshed
Paragraph 1 of the ExxonMobil and MSCC stipulations discusses a
contested case hearing and resultant February 2, 1996 stipulation and
incorporates the February 2, 1996 stipulation by reference. We do not
believe it is appropriate to incorporate the February 2, 1996
stipulation into the SIP because it discusses procedures and schedules
for developing emission limitations for ExxonMobil and MSCC that have
subsequently been developed and that, for MSCC, are not approvable (see
discussion on stack height issue at MSCC in section II.B.2, above).
Paragraph 1 of the ExxonMobil and MSCC stipulations also contains a
statement that the company enters into the stipulation ``in part, to
preserve [the company's]
rights to apportionment of the airshed
resulting from the present SIP revision.'' Insofar as this statement
implies that the companies or other air pollution sources are entitled
to a property interest in the ambient air in the Billings/Laurel area
or enjoy a right to pollute the ambient air, this statement conflicts
with the purpose and requirements of the Act and has no basis under
federal law. By this statement we do not mean that we do not recognize
emission rights created by statute (e.g., Titles I and IV of the Act).
However, the phrase ``right of apportionment of the airshed'' implies
possessory rights to the ambient air. We are concerned that the phrase
might imply rights less conditional than those created by the Act.
Therefore, we are disapproving paragraph 1 of the ExxonMobil and MSCC
stipulations.
4. MSCC Auxiliary Vent Stacks
We are disapproving the MSCC auxiliary vent stacks emission
limitation (section 3(A)(4) of MSCC's exhibit). We believe it is
necessary to disapprove this emission limitation because the exhibit
does not restrict the sulfur content of the fuel burned in the boilers
and heaters, when they are exhausting from auxiliary vent stacks, and
lacks a monitoring method that would make the emission limitation
practically enforceable. Without a restriction on the fuel burned and a
compliance monitoring method, there is the potential that exceedances
of the emission limitation would go undetected.
5. Attainment Demonstration \7\
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\7\ One commenter stated that we did not acknowledge that
Montana submitted two separate attainment demonstrations for SO2--
one for the Billings area and one for the Laurel area. The commenter
indicated that the Laurel area was modeled assuming the SIP
prescribed emission limitations for Cenex and the pre-SIP potential
emissions for the Billings sources. Therefore, the Laurel SIP
demonstrates compliance with the NAAQS regardless of whether a
revised SIP is approved and implemented in Billings. The Billings
area was modeled assuming all sources in Laurel and Billings area
are at SIP prescribed emission rates. Therefore, the Billings SIP
depends upon approval of the Laurel SIP to demonstrate attainment.
The commenter is requesting that we acknowledge the two attainment
demonstrations in our final action and treat the two separately in
that action. We agree with the commenter and acknowledge that there
are two attainment demonstrations--one for the Billings area and one
for the Laurel area. However, since the flare issue applies to
sources in Billings and in Laurel, we still believe the attainment
demonstration for both areas should be disapproved for lack of
enforceable flare emissions at the applicable sources.
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For us to fully approve a SIP, the SIP must show that the NAAQS
will not be violated, i.e., that the area demonstrates attainment.
Attainment demonstrations are usually carried out with computer models
that are approved by us. The computer models take numerous factors into
consideration to predict the effects that emissions from various
sources will
[[Page 22171]]
have on levels of pollutants in the air. Models consider the typical
meteorology and topography of the area, as well as physical parameters
at a plant site, e.g., the height, temperature, and velocity at which
pollutants are emitted. Based on these factors, as well as restrictions
placed on sources to control their emissions, models are used to
predict the highest pollution levels that can be expected to occur in
the future. For the reasons discussed below, we are disapproving the
attainment demonstrations for the Billings/Laurel SIP.
a. Improper Stack Height Credit and Emission Limitation at MSCC
The MDEQ used EPA-approved dispersion models to demonstrate
attainment of the SO2 NAAQS in the Billings/Laurel area. However, the
modeling for the July 29, 1998 submittal of the SIP relied on emission
limitations at MSCC that were established with a stack height credit
that exceeded the good engineering practice (GEP) stack height. As
discussed above in section II.B.2, we are disapproving the emission
limitations and stack height credit for the 100-meter stack at MSCC. We
are also disapproving the attainment demonstration because it relies on
these improper emission limitations and stack height credit.
b. Lack of Flare Emission Limitations
With the July 29, 1998 submittal of the SIP, the State of Montana
removed all reference to flare emission limitations from the exhibits
submitted for Federal approval. In June 1998, the MBER adopted
``Additional State Requirements'' (hereinafter referred to as ``State-
only provisions'') for each of the seven sources in the Billings/Laurel
area. The State-only provisions include flare emission limitations and
reporting requirements for the four sources that have flares (Cenex,
Conoco, ExxonMobil, and MSCC). Because the State-only provisions were
not submitted for inclusion in the Billings/Laurel SO2 SIP, they may be
enforced only by the MDEQ.
Since flare emissions were considered part of the attainment
demonstration and since there appear to be routine emissions from
flares, we believe the SIP should contain enforceable emission
limitations for these emission points. Therefore, we are disapproving
the SIP as it applies to the attainment demonstration for lack of
enforceable emission limitations for flares. See our July 28, 1999
proposed rulemaking action, middle column, 64 FR 40801, for more
information on this issue.
c. Disapproval of MSCC Auxiliary Vent Stacks Emission Limitation
As indicated above, we are disapproving the emission limitation on
the auxiliary vent stacks in MSCC's exhibit because the exhibit does
not restrict the sulfur content of the fuel burned in the boilers and
heaters, when they are exhausting from auxiliary vent stacks, and lacks
a monitoring method that would make the emission limitation practically
enforceable. The attainment demonstration relies on the auxiliary vent
stacks emission limitation at MSCC. Since we are disapproving the
emission limitation, we believe it is also necessary to disapprove the
attainment demonstration.
6. MSCC 30-Meter Stack
We are limitedly disapproving/limitedly approving the MSCC 30-meter
stack emission limitation (section 3(A)(2) of MSCC's exhibit). We
believe it is necessary to limitedly disapprove this emission
limitation because the exhibit does not adequately limit the fuel
burned in the boilers and heaters that are exhausting from the 30-meter
stack, and does not provide a monitoring method that would make the
emission limitation practically enforceable.\8\
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\8\ In some cases, a SIP rule may contain certain provisions
that meet the applicable requirements of the Act, but that are
inseparable from other provisions that do not meet all the
requirements. Although the submittal may not meet all of the
applicable requirements, we may consider whether the rule, as a
whole, has a strengthening effect on the SIP. If this is the case,
limited approval may be used to approve a rule that strengthens the
existing SIP as representing an improvement over what is currently
in the SIP and as meeting some of the applicable requirements of the
Act. At the same time we would disapprove the rule of the SIP for
not meeting all of the applicable requirements of the Act. Under a
limited approval/disapproval action, we approve and disapprove the
entire rule even though parts of it do and parts do not satisfy
requirements under the Act. The rule remains a part of the SIP, even
though it has been limitedly disapproved, because the rule
strengthens the SIP. The disapproval only concerns the failure of
the rule to meet a specific requirement of the Act and does not
affect incorporation of the rule as part of the approved, federally
enforceable SIP.
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7. Burning of Sour Water Stripper (SWS) Emissions in the Flare at Cenex
and ExxonMobil
With the July 29, 1998 submittal of the SIP, Cenex's and
ExxonMobil's exhibits now allow SWS emissions to be burned in the
flare. As discussed above, flare emission limitations were deleted from
the July 1998 submittal. Therefore, SWS emissions, if burned in the
flare, are unregulated. We believe that unless flares have an
enforceable emission limitation, it is unacceptable to allow SWS
emissions to be burned in the flare. Because we believe that allowing
SWS emissions to be burned in the unregulated flare is not an
acceptable approach, we are disapproving those provisions of the Cenex
and ExxonMobil stipulations that would allow such approach (the
following phrase from section 3(B)(2) of Cenex's exhibit A and section
3(E)(4) of ExxonMobil's exhibit A: ``or in the flare''; the following
phrases in section 4(D) of Cenex's exhibit A and section 4(E) of
ExxonMobil's exhibit A: ``or in the flare'' and ``or the flare''.)
8. Reasonably Available Control Measures (RACM) Including Reasonably
Available Control Technology (RACT) and Reasonable Further Progress
(RFP) at Cenex
As indicated earlier, we are disapproving the attainment
demonstration for the SIP. Because we are disapproving the attainment
demonstration, we conclude that the RACM (including RACT) and RFP
requirements have not been met in the Laurel SO2 nonattainment area.\9\
See discussion in sections III.C.(15) and (16) of our TSD for further
information.
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\9\ RACM (including RACT) and RFP requirements only apply in
areas designated as nonattainment.
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C. Why Is EPA Proposing Action on Parts of the State of Montana's Plan?
In our July 28, 1999 proposed rulemaking action, we proposed to
conditionally approve several provisions of the Billings/Laurel SO2 SIP
based on a commitment from the Governor of Montana to adopt specific
enforceable measures by a specified date. See the July 28, 1999 action,
64 FR 40802--40803, for a complete discussion of those parts of the
plan we proposed to conditionally approve. On May 4, 2000, the Governor
of Montana submitted a SIP revision to fulfill his commitment. Since
the Governor has fulfilled his commitment, we believe it is not
necessary to finalize the conditional approval. Instead, a separate
proposed rulemaking on parts of the July 29, 1998 submittal (i.e.,
those parts we proposed to conditionally approve on July 28, 1999) and
all of the May 4, 2000 submittal (which in some cases modified the July
29, 1998 submittal) is also being published today.
The specific provisions of the July 29, 1998 submittal on which we
are proposing a separate action today include:
(1) YELP's emission limitations (section 3(A)(1) through (3) of
YELP's exhibit);
[[Page 22172]]
(2) ExxonMobil's coker CO-boiler emission limitation (section
3(B)(1) of ExxonMobil's exhibit);
(3) ExxonMobil's F-2 crude/vacuum heater stack emission limitations
and attendant compliance monitoring methods (section 3(A)(2) of exhibit
A; section 3(B)(3) of exhibit A; the following phrase from section
3(E)(4) of exhibit A ``except that the sour water stripper overheads
may be burned in the F-1 Crude Furnace (and exhausted through the F-2
Crude/Vacuum Heater stack) or in the flare during periods when the FCC
CO Boiler is unable to burn the sour water stripper overheads, provided
that: (a) such periods do not exceed 55 days per calendar year and 65
days for any two consecutive calendar years, and (b) during such
periods the sour water stripper system is operating in a two tower
configuration.''; section 4(E) of exhibit A; and method #6A of
attachment #2, of exhibit A);
(4) ExxonMobil's fuel gas combustion emission limitations and
attendant compliance monitoring method (sections 3(A)(1), 3(B)(2),
4(B), and 6(B)(3) of ExxonMobil's exhibit); and
(5) Cenex's combustion sources emission limitations and attendant
compliance monitoring methods (section 3(A)(1)(d) of exhibit A; the
following phrase from section 3(B)(2) of exhibit A ``except that those
sour water stripper overheads may be burned in the main crude heater
(and exhausted through the main crude heater stack) or in the flare
during periods when the FCC CO boiler is unable to burn the sour water
stripper overheads from the ``old'' SWS, provided that such periods do
not exceed 55 days per calendar year and 65 days for any two
consecutive calendar years.''; section 4(B) of exhibit A; section 4(D)
of exhibit A; and method #6A of attachment #2 of exhibit A.)
Because we are proposing separate action on the above provisions,
at this time we are not incorporating these provisions into the
Federally approved SIP. See the regulatory text that follows at the end
of this document.
D. What Happens When EPA Approves Parts of the State of Montana's Plan?
Once we approve a SIP, or parts of a SIP, the portions approved are
legally enforceable by us and citizens under the Act.
E. What Happens When EPA Disapproves Parts of the State of Montana's
Plan?
Once we disapprove a SIP, or parts of a SIP, the disapproved
portions are still enforceable at the State level but not at the
Federal level. By disapproving parts of the plan, we are determining
that the requirements necessary to demonstrate attainment in the area
have not been met and we may develop a plan or parts of a plan to
assure that attainment will be achieved. Also, in some cases, once we
disapprove a plan, sanctions may be imposed. As noted below, at this
time, sanctions will not be imposed in the Billings/Laurel area as a
result of this partial and limited disapproval.
F. What Happens When EPA Limitedly Approves and Limitedly Disapproves
Parts of the State of Montana's Plan?
Once we limitedly approve/disapprove a SIP, or parts of a SIP,
those provisions are legally enforceable by us and citizens under the
Act. Under a limited approval/disapproval action, we approve and
disapprove the entire rule even though parts of it do and parts do not
satisfy requirements under the Act. The rule remains a part of the SIP,
however, even though there is a disapproval, because the rule
strengthens the SIP. The disapproval only concerns the failure of the
rule to meet specific requirements of the Act and does not affect
incorporation of the rule as part of the approved, federally
enforceable SIP. To the extent the rule fails to satisfy requirements
of the Act, we intend to develop a plan or parts of a plan to meet such
requirements.
III. Other Issues Pertaining to State Authority
A. How Do the State-Only Provisions Affect EPA's Actions?
In our July 28, 1999 proposed rulemaking action we indicated that
in June 1998, the MBER adopted ``Additional State Requirements'' for
each of the seven sources in the Billings/Laurel area. These
requirements (hereinafter referred to as the ``State-only provisions'')
were not submitted for inclusion in the SIP and are enforceable only by
the State of Montana. See 64 FR 40803, bottom right column of our July
28, 1999 action for a complete discussion of the State-only provisions.
We have considered the comments received on our discussion of
State-only provisions in our proposal and still believe it is
appropriate to conclude that since the State-only provisions were not
included in the Billings/Laurel SO2 SIP, we are not approving or
disapproving these provisions nor are we relying on these provisions in
approving or disapproving other provisions in the submitted SIP.
Nothing in this action should be construed as making any determination
or expressing any position regarding the State-only provisions or their
impact on the SIP. State-only provisions can affect only State
enforcement of the SIP and cannot have any impact on federal
enforcement authorities. We may at any time invoke our authority under
the Act, including, for example, sections 113, 114, or 167, to enforce
the requirements of the Billings/Laurel SO2 SIP independent of any
State enforcement effort. We may take action to enforce the SIP
regardless of any State compliance determination or any constraint on
State enforcement discretion which the State-only provisions may
impose. In addition, citizen enforcement under section 304 of the Act
is likewise unaffected by the State-only provisions.
If we were to determine that the State-only provisions, as
implemented, appeared to limit, constrain, or otherwise have a chilling
effect on state enforcement of the SIP, we would reconsider our
approval or take other appropriate action under the Act. Our
reconsideration could occur under section 110(k)(6) of the Act or we
could complete another SIP Call under sections 110(a)(2)(H) and
110(k)(5) of the Act. Other appropriate action could include a finding
of failure to implement the SIP under section 179(a)(4) of the Act or
enforcement action under section 113(a)(2) of the Act, or both.
B. How Does Montana's Environmental Audit Act Affect EPA's Actions?
On May 5, 1997, the Governor of Montana signed a bill enacted by
the legislature (the Voluntary Environmental Audit Act, Mont. Code Ann.
Secs. 75-1-101 et seq. (1999), (H.B. 293, effective October 1, 1997))
that creates immunity under State law from penalties for violations
discovered during a voluntary environmental audit and creates a
judicial privilege under State law for information contained in an
environmental audit report.
In our July 28, 1999 action we indicated that nothing in our
proposal action should be construed as making any determination or
expressing any position regarding the State of Montana's audit
privilege and penalty immunity law or its impact upon any provisions in
the SIP, including the proposed revision at issue.
However, our concerns about the effect of the audit law on the
State's ability to enforce the SIP have been addressed by a formal
agreement with the State. On December 13, 1999, EPA and the State
entered into a Memorandum of Agreement (``MOA'') (see document # IV.C-
32) concerning the effects of the audit law on state implementation and
enforcement of all federal environmental programs in
[[Page 22173]]
Montana. Under the MOA, as long as the agreement and the State's legal
interpretations of the audit law are in effect and functioning as
intended, we and the State agree that State environmental programs,
including the SIP, have sufficient authority to obtain and maintain EPA
approval.
The State of Montana's audit privilege and immunity law affects
only state enforcement and does not have any impact on federal
enforcement authorities. We may at any time invoke our authority under
the Act, including for example, sections 113, 114, or 167, to enforce
the requirement or prohibitions of the State of Montana's plan,
independent of any state enforcement effort. In addition, citizen
enforcement under section 304 of the Act is likewise unaffected by a
state audit privilege or immunity law.
IV. Other Rulemaking Actions
A. How Does This Final Action Relate to EPA's SIP Call?
In our July 28, 1999 proposal we indicated that our March 4, 1993
letter requesting revision of the Billings/Laurel area SO2 SIP (see
document # II.G-1) stated that the letter was not final Agency action
subject to judicial review, and that a final Agency action would occur
when we made a binding determination regarding the State's response. We
have considered the comments received on our proposed rulemaking action
and still believe it is appropriate to finalize action on the SIP Call
and on the State of Montana's response to the March 4, 1993 letter; we
are making a binding determination regarding the SIP Call and the State
of Montana's response to the letter with this final rulemaking action.
B. Why Is EPA Not Imposing Sanctions?
In our July 28, 1999 proposed rulemaking action, starting at 64 FR
40804, right column, we proposed that the sanctions specified in
section 179(b) of the Act should apply if our proposed disapproval
action became a final disapproval action. We also requested comment on
whether we should accelerate the sanctions under section 110(m) of the
Act. After reviewing the comments\10\ received on our proposal action,
we have decided not to select the order of sanctions that would apply
in the Billings/Laurel area at this time. Consequently, if the 18-month
sanctions clock that starts with today's disapproval of Montana's SIP
expires without the State having corrected the identified deficiencies,
no sanctions will be imposed. In the future, if we choose to select the
order of mandatory sanctions or to apply early discretionary sanctions,
we would do so through rulemaking.
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\10\ See footnote 7 above.
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V. What Comments Were Received on EPA's Proposed Action and How Is
EPA Responding to Those Comments?
Summary of Comments and Responses
Following is a summary of the comments received on the proposed
rulemaking and our responses. The following is an outline of the
subjects on which we received comments:
A. SIP Call
B. Sanctions
C. Flares
D. Dispersion Modeling
E. EPA's Partial Approval
F. Due Process for SIP Approval
G. Escape Clause
H. Language in ExxonMobil and MSCC Stipulations Related to
Incorporation of Earlier Stipulations and Apportionment of the
Airshed
I. Default Approval of SIP
J. Department Discretion
K. Quarterly Data Recovery Rate (QDRR)
L. Effect of the Montana Voluntary Environmental Audit Act
M. Effect of State-only Provisions
N. Enforcement and MDEQ Staffing
O. Reasonably Available Control Measures (RACM) Including Reasonably
Available Control Technology (RACT) and Reasonable Further Progress
(RFP) at Cenex
P. MSCC Auxiliary Vent Stacks
Q. MSCC's 30-meter Stack
R. ExxonMobil's and Cenex's Refinery Fuel Gas Limitation
S. Variable Emission Limitations
T. Minor Sources
U. Compliance Determining Method--ExxonMobil's Coker CO-Boiler Stack
and F-2 Crude/Vacuum Heater Stack
V. Effect of the 1990 Amendments to the Clean Air Act
W. Stack Height Issues
A. SIP Call
We issued a request for revision of the Billings/Laurel area SO2
SIP by letter to the Governor of Montana, dated March 4, 1993 (see
document # II.G-1). The request letter reflected our preliminary
finding regarding the SIP's substantial inadequacy (SIP Call), and was
published in the Federal Register on August 4, 1993 (58 FR 41430) (see
document # II.G-3). In the request letter, we declared that the SIP
Call would become final agency action when we made a binding
determination regarding the State of Montana's response to the SIP
Call. We proposed to make such binding determination regarding the SIP
Call when we proposed to partially approve, conditionally approve, and
partially disapprove the Billings/Laurel SO2 SIP revisions submitted by
the State on Montana in response to the request letter. See 64 FR
40791, 40804 (July 28, 1999) (see document # III.A-2).
Summary of Comments and Response
Two commenters objected that the SIP Call is invalid and should be
withdrawn.
We have considered the comments received and still believe our
March 4, 1993 letter was appropriate and that we should make the SIP
Call for the Billings/Laurel area a final agency action.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment #'s 1, 125; Goetz letter, document # IV.A-18, exhibit D,
comment # III, p. 43) stated that the SIP Call is invalid and that
subsequent actions by the State in response to the 1993 letter and by
EPA on the State's SIP revision are invalid as well. These commenters
submitted extensive comments on the dispersion modeling that was the
basis of the 1993 letter, claiming that the modeling was defective and
was not supported by monitoring data.
Response: We will address the comments on dispersion modeling and
monitoring in section V.D. of this document, together with similar
comments concerning the State's modeled demonstration of the
effectiveness of the new SIP emission limitations. Please see section
V.D., below (``Dispersion Modeling''). Here we will address other
comments on the validity of the SIP Call.
(2) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 1; MSCC letter, document # IV.A-20, comment #'s 3.A, 3.B),
stated that the SIP Call violates due process because it undoes an
earlier approval of the existing SIP, while the letter was not made by
rulemaking, was not properly noticed, and did not provide for timely
and effective challenge because it was not denoted a final agency
action. The commenter further stated that irreversible changes occurred
without opportunity to challenge the underlying premises of the 1993
letter. Another commenter (Goetz letter, document # IV.A-18, exhibit D,
comment # III, p. 43) stated that because the 1993 letter was not
binding, presumably because it was not issued by rulemaking, no one
could challenge its validity.
Response: The SIP Call does not violate due process. The provisions
of the Act that authorize us to call for SIP revisions do not require
rulemaking
[[Page 22174]]
until the Agency proceeds to make the SIP Call binding and final.
Sections 110(a)(2)(H) and 110(k)(5) of the Act require (1) that we
notify the State when we find that the applicable implementation plan
is substantially inadequate to protect the NAAQS, and (2) that we make
the notice public. When we sent our letter to the Governor of Montana
on March 4, 1993 and published the letter in the Federal Register, see
58 FR 41430 (August 4, 1993) (document # III.G-3), we in effect
provided our preliminary views regarding the SIP's substantial
inadequacy and provided the State an early opportunity to respond to
our assessment. Thus, we did not make a final, binding finding, and
thus were not required to use notice and comment rulemaking procedures
to issue the letter. Rather, the final binding action regarding the SIP
Call, as well as our action on the State's response to the 1993 letter,
is occurring in today's rulemaking. The SIP Call does not ``undo'' our
prior approval of the 1977 SIP for the area or turn that approval into
a disapproval. Any SIP Call denotes that the existing SIP has become
inadequate, whether due to changes in conditions such as increased
emissions, a change in requirements, or, as in this case, a change in
our ability to measure the effectiveness of the SIP control strategy to
protect air quality.
The opportunity to participate in the SIP development process that
began with our letter to the Governor was provided by the public
participation requirements of the Montana SIP and the proposed
rulemaking in this action. See 64 FR 40791, 40806 (July 28, 1999)
(document # III.A-2). The opportunity to review and comment on the
proposed rule, which the commenters have exercised, satisfies the
requirements of procedural due process mandated for SIP approval
actions by sections 110(a) and 110(k) of the Act and section 553 of the
Administrative Procedure Act. Under those provisions, the requirements
of due process are satisfied by publication of a notice of proposed
rulemaking with an opportunity for submission of written comments prior
to final action. The Act does not require formal adjudication or formal
rulemaking. See Cleveland Electric Illuminating Co. v. E.P.A., 572 F.2d
1150, 1157 (6th Cir. 1978); Buckeye Power, Inc. v. EPA, 481 F.2d 162,
172 (6th Cir. 1973).
The appropriate mechanism for obtaining a formal hearing on our
rulemaking on the SIP Call and on the SIP is to file a petition for
review of this final action in the United States Court of Appeals for
the Ninth Circuit, as provided by section 307(b) of the Act. The
procedural requirements for exercising the opportunity for judicial
review of our final action are discussed elsewhere in this document.
(3) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 1, 2nd page, 3, 4, 66 and other comments) stated that our
SIP Call is an entirely discretionary act that was inadequately
justified.
Response: The statutory provision authorizing SIP Calls provides
that ``[w]henever the Administrator finds that the applicable
implementation plan for any area is substantially inadequate to attain
or maintain the relevant national ambient air quality standard.* * *
the Administrator shall require the State to revise the plan as
necessary to correct such inadequacies.'' Section 110(k)(5) of the Act
(emphasis added). While it is true that EPA has some discretion in
finding whether a SIP is substantially inadequate, the use of the
imperative ``shall,'' rather than the optional ``may,'' appears to
require EPA action as mandatory and not discretionary, once we make a
finding of substantial inadequacy.
The same commenter believes the SIP Call is not adequately
justified and that the Administrator should withdraw the 1993 letter.
We believe our technical support document for the SIP Call (document #
II.G-2) adequately justifies our final binding decision to call for a
SIP revision and that no withdrawal of the1993 letter is necessary.
(4) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 1, 2nd page) stated that our SIP Call intrudes on the primary
responsibility of the State to implement the Clean Air Act, contrary to
section 101 of the Act. Another commenter (Goetz letter, document #
IV.A-18, exhibit D, comment # V, p. 61) raised the same objection to
our proposed action on the SIP.
Response: Section 101 of the Act, ``Congressional findings and
declaration of purpose,'' is not a prescriptive provision and does not
require particular action by anyone. But it does provide a statement of
Congressional intent, which the remaining provisions of the Act
effectuate. For example, section 101(a)(3) states a congressional
finding that air pollution prevention and control are the ``primary
responsibility of States and local governments''; section 101(a)(4)
states a finding that ``[f]ederal financial assistance and leadership
is essential for the development of cooperative Federal, State,
regional, and local programs to prevent and control air pollution.''
These and other provisions of section 101 of the Act declare an
intent to create a cooperative relationship between the federal
government and the States ``to protect and enhance the quality of the
Nation's air resources, so as to promote the public health and
welfare'' as expressed by section 101(b). As the courts have
recognized, ``The CAA simply 'establishes a program of cooperative
federalism that allows the States, within limits established by federal
minimum standards, to enact and administer their own regulatory
programs, structured to meet their own particular needs.' ''
Commonwealth of Virginia v. Browner (80 F.3d 869, 883 (1996) (quoting
Hodel v. Virginia Surface Mining & Reclamation Ass'n, 452 U.S. 264,
289, 101 S.Ct. 2352, 2367-68 (1981)).
The intent to create a cooperative relationship for air pollution
control is effected by the other provisions of the Act, including
section 109, which authorizes us to establish NAAQS; by section 110(a),
which directs States to assume the primary responsibility of developing
SIPs to protect the NAAQS; and by section 110(k)(5), which authorizes
us to take a leadership role by calling for revision when SIPs are
found inadequate. Montana's action here, developing and submitting a
SIP revision in response to our 1993 letter, fulfills the congressional
intent that States take primary responsibility for air pollution
control. In the federal partnership, both functions are necessary: both
the primary responsibility assumed by the States and our standard-
setting and oversight role.
(5) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment # 2; Goetz letter, document # IV.A-18, exhibit D, comment, p.
9) stated that we improperly constrained the State's action in
responding to the 1993 letter, by placing time limits on the State's
response and threatening to impose sanctions and withhold federal funds
if the State did not submit timely SIP revisions. One of the commenters
(MSCC letter, document # IV.A-20, comment # 4F) also stated that until
we have promulgated a formal SIP Call for Montana, and given Montana
the statutory time following final promulgation of the formal SIP Call,
we are not required and may not be authorized to promulgate a FIP.
Another commenter (McGarity letter, document # IV.B-1) stated that the
process has taken too long.
Response: The maximum allowable time limits for submission of
revisions in response to a SIP Call are established by statute. Section
110(k)(5) of the Act
[[Page 22175]]
provides that we ``may establish reasonable deadlines (not to exceed 18
months after the date of such notice) for the submission of such plan
revisions.'' (Emphasis added.) However, the statute does not require us
to establish a deadline in all cases. In our letter of March 4, 1993,
we requested that Montana submit its revisions within an 18-month
timeframe, which is consistent with the maximum allowable time where we
are making a SIP Call binding and final. Under the letter, the SIP
revisions were due on September 4, 1994 if the State chose to comply
with the request. The State submitted the revisions on September 6,
1995, nearly a year later than this date. These revisions were modified
and resubmitted on August 27, 1996, April 2, 1997 and July 29, 1998. In
light of these facts, it is not necessary to establish a further
schedule and deadline for the State to respond to the SIP Call in
today's rulemaking, since we already have received the State's
response.
We did not impose sanctions on Montana for failure to submit the
revisions on time, but we did indicate that sanctions would apply in a
letter to the State dated September 19, 1994 (document # IV.C-31). This
letter and subsequent letters to the State on the timing of sanctions,
dated March 14, 1996 (document #'s II.B-16 and B-17), were premature,
and we later corrected them. Our authority to impose sanctions under
section 179 of the Act can only be implemented after we conduct
rulemaking to select the order of the sanctions to be imposed for
failure to meet requirements of the Act. See section 179(a) of the Act.
Because we did not promulgate a general rule for applying sanctions for
failure to meet a SIP Call, we can impose them only through specific
rulemaking that achieves two things: first, making the SIP Call binding
and final so that the State's response becomes a ``required''
submission under the Act; and second, selecting the order of mandatory
sanctions that will apply if the State fails to respond or if EPA
disapproves the State's response. In our proposed rulemaking action we
proposed to take the prerequisite rulemaking actions and to apply
sanctions in the event that our partial disapproval of the SIP
revisions became final action. See 64 FR 40791, 40804 (July 28, 1999)
(document # III.A-2). (Our final action on the proposal to impose
sanctions is discussed in section V.B., below.)
With respect to whether we can promulgate a FIP without completing
formal rulemaking on the SIP Call, by this action, we are promulgating
a formal SIP Call and can now propose a FIP to fill any gaps created by
our disapproval of the Billings/Laurel SO2 SIP. We do not agree with
the commenter that the Act requires us to give the State additional
time to respond to the SIP Call and SIP disapproval, before we propose
a FIP. Section 110(c) of the Act requires that we promulgate a FIP ``at
any time within 2 years after'' we disapprove a SIP revision in whole
or in part. There is no minimum time period before we may promulgate a
FIP, but rather a two-year maximum time within which we must promulgate
a FIP. Because the State has already had nearly nine years in which to
respond to the initial 1993 letter, we do not believe that allowing
additional time will serve the public interest in protecting the NAAQS
through federally enforceable limitations on SO2 emissions.
(6) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment # 2; Goetz letter, document # IV.A-18, exhibit D, comment # 2,
p. 9) also stated that the untimely threat to impose sanctions exerted
improper and extreme pressure on Montana and the sources in the area to
respond to the 1993 letter. One commenter (MSCC letter, document #
IV.A-19, comment # 1, 3rd page) stated that the threat of sanctions was
coercive and had the effect of forcing the State to impose emission
limitations that were unauthorized and unconstitutional.
Response: These comments will be addressed in section V.E., below,
discussing the Tenth Amendment and other constitutional and statutory
challenges to our SIP action.
(7) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 1, 1st page) stated that the 1993 letter was invalid because
the letter incorrectly stated that the existing SIP for the area did
not contain enforceable emission limitations.
Response: Contrary to the commenter's statement, the 1993 letter
does not contain a statement that the pre-1993 SIP did not include
enforceable emission limitations. When we issued the 1993 letter, we
were aware that some enforceable limitations on SO2 emissions were in
place. We took those limitations into account in our analysis. For
example, the modeling demonstration that formed the basis of the 1993
letter showed violations of the NAAQS for SO2 at emission levels
allowed under existing emission limitations. The 1993 letter did state
our view that the SIP in effect at that time was inadequate to attain
and maintain the SO2 NAAQS and that emission reductions would likely be
necessary to protect the NAAQS.
(8) Comment: One commenter (MSCC letter, document # IV.A-20,
comment #'s 3J, 3K, 3N, 3Q, 3R) stated that the SIP Call is not
binding, adequate or legally effective to say the SIP was inadequate
because allowable and actual emissions have been reduced and voluntary
improvements have occurred since 1993. Additionally, the commenter
stated that since the 1993 letter additional information and facts have
become available to further dispute or moot the results of the 1993
modeling and any opinion based thereon.
Response: The 1993 letter was supported by the evidence available
at the time it was issued. That evidence could not have taken into
account future events such as more restrictive emission limitations in
state permits. Such later actions are irrelevant to the validity of the
1993 letter, though possibly relevant to Montana's response to the
letter. Voluntary reductions in emissions since the 1993 letter are
also irrelevant; they do not affect the validity of the 1993 letter or
our rulemaking on the SIP Call and the SIP revisions.
(9) Comment: Two commenters (MSCC letter, document # IV.A-20,
comment #'s 3.H., 3.L; Goetz letter, document # IV.A-18, exhibit D,
comment # III.B, pp. 44-45) stated that the SIP Call is not binding,
adequate or legally effective to say the SIP was inadequate because
ambient monitoring in the Billings/Laurel area, both before and after
the 1993 letter, did not show any violations of the SO2 NAAQS.
Response: For a discussion of whether contrary monitoring data
invalidate the computer modeling used for the SIP Call and SIP
development, readers are referred to the response to comments on
modeling in section V.D., below. With respect to measurements of
current concentrations, the emissions inventory for the Billings/Laurel
area indicates that actual SO2 emissions have declined since 1993. One
commenter (MSCC letter, document # IV.A-20, comment # 3.Q) notes that
CEMS at the sources show lower emission rates now than at the time of
the modeling. Ambient concentrations of SO2 measured by the area's
monitoring network, not surprisingly, show a similar decline. To the
extent that these reductions reflect the State's efforts to restrict
emissions as part of its control strategy, they demonstrate the
effectiveness of Montana's response to the SIP Call.
B. Sanctions
We proposed that the regulatory scheme issued for sanctions
generally, under 40 CFR section 52.31, should also
[[Page 22176]]
apply here if our proposed partial disapproval of the SIP became a
final action or if our adopted final conditional approvals later
converted to disapprovals. We proposed to apply the sanction rule's
provisions regarding the timing of sanctions. We also asked for comment
on whether we should impose sanctions under section 110(m) of the Act
to make the sanctions effective immediately upon the effective date of
partial disapproval or conversion from conditional approval to
disapproval, and on the geographic scope of any such discretionary
sanctions.
Summary of Comments and Response
Eight commenters submitted comments on our sanctions proposal. Five
of the eight commenters were opposed to our imposing sanctions, one
commenter seemed only opposed to sanctions in Billings, and two
commenters felt we should go beyond what was proposed and apply
sanctions throughout the State. Some commenters were also opposed to
applying sanctions immediately.
We have considered the comments received, and in our final rule, at
this time, we have decided not to select the order of sanctions that
would be necessary to apply mandatory sanctions (section 179(b)), or to
impose discretionary sanctions (section 110(m)) in the Billings/Laurel
area or anywhere else in the State of Montana. Thus, sanctions are not
automatic in the Billings/Laurel area as a result of our partial and
limited disapproval of the SIP, even if the State does not correct the
identified deficiencies within the 18-month period starting with
today's disapproval. To apply mandatory sanctions under section 179, we
must complete a rulemaking action to specify the order of sanctions.
Because the sanctions are not automatic before such action is
completed, we believe we can use some of the principles of
discretionary sanctions in deciding whether or not sanctions should be
applied in the Billings/Laurel area.
We are not required to apply discretionary sanctions under section
110(m) of the Act. Section 110(m) says ``[t]he Administrator may apply
any of the sanctions listed in section 179(b) at any time (or at any
time after) the Administrator makes a finding, disapproval or
determination under paragraphs (1) through (4), respectively, of
section 179(a) in relation to any plan or plan item...required under
the Act...'' Further, in the preamble of our rulemaking action for
discretionary sanctions we indicated that we will exercise section
110(m) sanctions earlier than 18 months only in cases where: (1) the
State has indicated an explicit resistance to resolving a plan or
program deficiency or to making a required plan or program submittal;
or (2) special circumstances, particular program needs, or time
constraints dictate the need for use of such sanctions. See 59 FR 1481
(middle column), January 11, 1994.
In this particular case, the State initially submitted a SIP in
September 1995 and then spent several years revising and updating the
SIP to, among other things, address our concerns with previous SIP
submittals. In a letter dated September 27, 1999 from Mark Simonich,
Montana Department of Environmental Quality (MDEQ), to William
Yellowtail, EPA, the MDEQ expressed a desire to correct the SIP so that
it is approvable. (See document # IV.A-31.)
This history shows that the State has not shown resistance to
resolving its plan deficiency or to making the required plan submittal.
In addition, sources were required to meet the emission limitations in
the Billings/Laurel SO2 SIP when the State's Board Order was signed
(June 12, 1998), except where another effective date is specified in
the exhibit A or attachment(s). Therefore, on the whole, the plan is
being implemented now.
Because of the State's efforts to submit an approvable SIP and
because the SIP is being implemented, we believe that it is not
appropriate to apply discretionary sanctions in the Billings/Laurel
area, or anywhere else in the State of Montana, at this time. In the
future, if we choose to apply discretionary sanctions or to select the
order of mandatory sanctions that would apply, we would do so through
rulemaking.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: Several commenters stated that sanctions are not
appropriate in any form, because there have been substantial reductions
in SO2 emissions and ambient concentrations in the area; the area meets
the NAAQS; and the State and industry have made a good faith effort to
submit a SIP to us. (See State letter, document # IV.A-23, comment #'s
1A, 1B, 1C, 1D, 1E; Cenex letter, document # IV.A-26, Montana Petroleum
Association letter, document # IV.A-17; ExxonMobil letter, document #
IV.A-28, State letter, document # IV.A-31, MSCC letter, document #
IV.A-20, comment # 4B, 6A; MSCC letter, document # IV.A-19, comment #'s
112, 114.)
Response: We agree that the State of Montana has made a good faith
effort to submit an approvable SIP and that is why we have decided not
to apply sanctions at this time. However, we do not agree that
substantial reductions in SO2 emissions and ambient concentrations
alone should warrant not applying the sanctions. Although sources over
the past several years have reduced their actual SO2 emissions, and
there has been a corresponding reduction in monitored ambient
concentrations, the SIP allows sources to emit more SO2 than they
actually do. Also, we have long held that SO2 monitoring may not be a
true indication of ambient concentrations because of the nature of SO2
plumes. See our September 16, 1982 memorandum from Sheldon Meyers,
Director, Office of Air Quality Planning and Standards to David Kee,
Director, Air and Management Division, Region V, entitled ``Milwaukee
SO2 Nonattainment Designation,'' and April 21, 1983 memorandum from
Sheldon Meyers, Director, Office of Air Quality Planning and Standards
to Regional Air Division Directors, entitled ``Section 107 Designation
Policy Summary'' (document #'s IV.C-26 and IV.C-27, respectively). In
both memoranda, we indicate that in most SO2 cases, a small number of
monitors is usually not representative of the air quality for the
entire area. See also response to comments D.2.a. and b.
(2) Comment: One commenter stated that imposing sanctions on
Montana is unfair because the State made a good faith effort to develop
the plan; the plan contains all the necessary elements and shows
attainment; the plan may be unnecessary and later overturned by a court
or even a subsequent Administrator; and EPA's criticism of the lack of
approved emission limitations at this point source arises solely from
EPA's failure to approve a reasonable plan and demonstration, and not
the State's failure to submit it. The commenter also stated that
Montana is not being treated equally with other areas that are
attaining the NAAQS. (See MSCC letter, document # IV.A-20, comment #'s
4B, 4D, 4E, 6; MSCC letter, document # IV.A-19, comment # 112.)
Response: As indicated above, we agree that the State of Montana
has made a good faith effort to submit an approvable SIP and that is
why we have decided not to apply sanctions at this time. We do not
agree that the plan submitted by the State contains all the necessary
elements and shows attainment. See our proposed rulemaking action and
TSD, document #'s III.A-2 and III.B-1, respectively, for a complete
explanation of why we do not believe the submitted plan contains all
the necessary elements. We do not
[[Page 22177]]
agree that we should not impose sanctions because of speculation about
future challenges to our action or subsequent EPA Administrators.
Finally, we do not agree that Montana is not being treated equally with
other areas that are attaining the NAAQS.
(3) Comment: Several commenters stated acceleration of sanctions is
not appropriate. (See Conoco letter, document # IV.A-24; Cenex letter,
document # IV.A-26.) One commenter stated it is not appropriate to
accelerate sanctions for failure to submit a SIP that we could approve
in response to a SIP Call the commenter believes was not binding. (See
MSCC letter, document # IV.A-19, comment # 111.)
Response: We agree that it is not appropriate to accelerate
sanctions, at this time. The ability to accelerate sanctions comes
under our discretionary sanction authority in section 110(m) of the
Act. As indicated above, in the preamble of our rulemaking action for
discretionary sanctions we indicated that we will exercise section
110(m) sanctions earlier than 18 months only in cases where: (1) the
State has indicated an explicit resistance to resolving a plan or
program deficiency or to making a required plan or program submittal;
or (2) special circumstances, particular program needs, or time
constraints dictate the need for use of such sanctions. See 59 FR 1481
(middle column) January 11, 1994. We believe the State has not shown an
explicit resistance to resolving a plan deficiency or making a required
plan submittal. At this time we do not believe there are special
circumstances which warrant accelerating sanctions.
We do not agree with the commenter who stated that we should not
accelerate sanctions because the plan is approvable and the 1993 letter
was not binding. The issue of whether the 1993 letter was binding is
discussed in section V.A., above. Our proposed rulemaking action and
TSD provides a full explanation of why we believe the SIP is not fully
approvable. See document #'s III.A-2 and III.B-1, respectively.
(4) Comment: Several commenters stated that sanctions are not
appropriate since we were involved when the SIP was developed. The
commenters stated our involvement blurred the State's primary role in
developing the SIP and our role in approving the SIP. (See State
letter, document #IV.A-23, comment #'s 1B, 1C, 1E; Cenex letter
document # IV.A-26)
Response: We do not agree that we should not impose sanctions since
we were involved when the SIP was being developed. We generally review
and comment on SIPs as they are being developed and during the public
comment period. Often states will ask for our interpretation of the
Act, regulations and guidance so that SIPs, once submitted, will be
approvable. In its comments on the proposal, the State of Montana
portrayed our involvement in the SIP development as ``extensive and at
times, overreaching.'' We do not agree with this characterization of
our involvement and review. However, since we are not applying
sanctions, at this time, we do not believe it worthwhile to debate the
appropriateness of our involvement with respect to whether that should
have any bearing on whether to apply sanctions.
(5) Comment: Several commenters stated that imposing sanctions
sends the wrong message to the State and sources for their efforts and
is inconsistent with the intent of Congress, which is clean air, not
punishment. (See State letter, document # IV.A-23, comment # 1E.)
Response: We do agree that, in this case, sanctions may send the
wrong message to the State for its SIP efforts and therefore we are not
applying the sanctions. We do not agree, however, that applying
sanctions would be inconsistent with Congressional intent. By
authorizing sanctions for certain kinds of state planning failures,
Congress intended to assure that SIPs and SIP revisions would be
developed on time, would provide adequate controls, and would otherwise
satisfy Act planning requirements.
(6) Comment: Several commenters stated that imposing sanctions in
this case is a discretionary act by EPA and due to the circumstances in
this case the sanctions should not be imposed. (See State letter,
document # IV.A-23, comment # 1E; Cenex letter, document # IV.A-26;
MSCC letter, document # IV.A-20, comment # 4A; MSCC letter, document #
IV.A-19, comment # 112.) One commenter stated we are creating a rule
structure just so that we could impose sanctions in Montana. (See MSCC
letter, document # IV.A-20, comment # 4A.) One commenter questions
whether we can impose discretionary sanctions under section 110(m) of
the Act in cases such as this where section 179 is not applicable. (See
State letter, document # IV.A-23, comment # 1E.)
Response: We agree that applying sanctions is a discretionary act
in this case and due to the circumstances the sanctions should not be
applied at this time. We also agree with the commenter that in our
proposal we were creating a rule structure to impose sanctions. Because
sanctions are not automatic in this particular case we believed we had
to create a rule to impose them.
With respect to the commenter who questioned whether we could apply
section 110(m) in cases where EPA is not exercising its authority under
section 179, we already addressed this issue when we finalized our
criteria for exercising discretionary sanctions under the title I of
the Act (59 FR 1476, January 11, 1994). In the January 11, 1994 action,
59 FR 1479-1480, we indicated that ``EPA believes that section 110(m)
and section 179, although interrelated, do set up two distinct
sanctions processes.'' Additionally, on page 1480 of the January 11,
1994 action, third column we indicated that ``EPA disagrees that
section 179 provides the sole authority for imposing sanctions. * * *
In fact, the EPA believes the reference to statewide sanctions under
section 110(m) makes it clear that section 110(m) establishes a
different authority to sanction states.* * *''
While our sanctions authority under both provisions is triggered by
a state failure regarding a required submission under the Act, we
believe we have independent authority under section 110(m) to impose
sanctions, even if we have not completed a separate rulemaking under
section 179 to select the sequence of mandatory sanctions. We are
choosing not to impose discretionary sanctions at this time. If we
decide to impose sanctions in the future under section 110(m) we would
propose them through notice and comment rulemaking and the public could
comment at that time.
(7) Comment: One commenter stated that sanctions are not
appropriate because the 1993 letter was not binding, adequate and/or
legally effective as a determination that the SIP was inadequate. The
same commenter stated we need to go through a rulemaking process on the
SIP Call before we can start a sanction clock. The commenter stated
that until we go through a rulemaking process we have circumvented the
public notice, comment and appeals process that should precede any
sanctions. (See MSCC letter, document # IV.A-20, comment #'s 3A, 3B,
4B, 4C, 4D, 5E.)
Response: In this case, we do not agree that sanctions would be
inappropriate merely because the 1993 letter was not binding. Today's
final action itself makes the SIP Call binding, and partially and
limitedly disapproves the State's response to the SIP Call. Section
179(a) of the Act provides the statutory authority to apply sanctions
for disapprovals of a SIP, in whole or in part, that is required to be
submitted
[[Page 22178]]
under a SIP Call (section 110(k)(5)). Today's rulemaking renders the
SIP Call binding and final, and takes final disapproval action on the
State's required response. Therefore, under the statute, EPA would have
the authority to select the order of sanctions that would be necessary
to apply mandatory sanctions (section 179(b)), or impose discretionary
sanctions (section 110(m)), if we conducted the prerequisite rulemaking
and if the State failed to correct the identified deficiencies within
18 months of such rulemaking.
(8) Comment: Several commenters stated the geographic scope of the
highway sanctions should be the entire state and the offset sanctions
the Billings/Laurel area. (See YVCC letter, document # IV.A-30.) One
commenter stated the geographic scope of the sanctions should be just
the Laurel area. (See Conoco letter, document # IV.A-25).
Response: As indicated above, at this time, we are deciding not to
apply sanctions anywhere in the State of Montana. Two commenters felt
we should apply 2-to-1 emission offset sanctions in the Billings area.
For the most part, 2-to-1 emissions offset sanctions can only be
applied in areas designated as nonattainment. If we had elected to
apply sanctions, since Billings is not a designated nonattainment area,
we could not apply 2-to-1 emission offset sanctions there. See our
January 11, 1994 final rulemaking action on discretionary sanctions, 59
FR 1479-1480, for a more detailed discussion on the geographic scope of
sanctions.
(9) Comment: Several commenters stated sanctions would
disproportionately affect Laurel and Cenex. (See Cenex letter, document
# IV.A-26; MSCC letter, document # IV.A-20, comment # 5; MSCC letter,
document # IV.A-19, comment # 114.) One commenter stated it is unfair
to apply sanctions in Laurel because Laurel is a nonattainment area
only in name; ambient data show the area is attaining the standard;
Laurel is being punished for issues that are occurring in Billings and
to which Laurel does not contribute. (See MSCC letter, document # IV.A-
20, comment #'s 5A, 5C; MSCC letter, documment # IV.A-19, comment #
114.) This same commenter stated that once an area is designated
nonattainment it is impossible to be redesignated to attainment. (See
MSCC letter, document # IV.A-20, comment # 5B.) Finally, this commenter
stated that Laurel's nonattainment designation occurred many years ago
and was not the result of the issues identified in the current SIP.
(See MSCC letter, document # IV.A-20, document 5D; MSCC letter,
document # IV.A-19, comment # 114.) This commenter further stated that
the CAA 1990 requirement that designations be reaffirmed is
unreasonable in this case. (See MSCC letter, document # IV.A-19,
comment #65.) This commenter stated that the area is more controlled
now than at the time of Laurel's nonattainment designation and that it
is hard to believe that not approving the SIP will jeopardize the
NAAQS. (See MSCC letter, document # IV.A-20, comment # 5G.)
Response: As indicated above, at this time, we are deciding not to
apply sanctions in Montana. If we had decided to apply sanctions just
in the nonattainment area impacted by the Billings/Laurel SO2 SIP, then
the commenters are correct that Laurel and Cenex would have been
impacted more by the sanctions then the rest of the area and sources.
We do not agree with the commenter who stated that applying sanctions
in Laurel would be punishing Laurel for a Billings issue. Our proposed
disapproval of the SIP, because of the lack of flare provisions, also
pertains to Laurel; flare issues pertain in Laurel and Billings.
One commenter questions whether Laurel should be designated as a
nonattainment area (presumably because the designation of Laurel
impacts the sanctions that could apply). The fact is that Laurel is a
designated nonattainment area. We cannot redesignate the area until the
State submits a redesignation request and maintenance plan which we can
approve. Contrary to the commenter's suggestion, redesignations of SO2
areas from nonattainment to attainment have occurred across the
country. See, for example, 66 FR 14087 (March 9, 2001) and 65 FR 35577
(June 5, 2000). Prior to the Clean Air Act Amendments of 1990 (1990
CAAA), Laurel had an approved Part D plan but was still designated as
nonattainment because the State had not submitted a redesignation
request. Because Laurel was designated as nonattainment prior to
enactment of the 1990 CAAA, upon enactment of the 1990 CAAA, Laurel
remained a nonattainment area by operation of law. See section
107(d)(1)(C)(i) of the Act. Although one of the commenters states these
requirements are unreasonable, we are required to implement the law.
Since the 1990 CAAA, we determined that the SIP for the Billings/Laurel
area was not adequate to protect the NAAQS. We do not believe we could
approve a redesignation request and maintenance plan for Laurel until
we determine that the SIP for Laurel is adequate to protect the NAAQS,
i.e., until we approve the SIP submitted in response to the SIP Call.
One commenter wonders how non-approval of the SIP will jeopardize
attainment since the area is more controlled now than when Laurel was
initially designated as nonattainment. What the commenter seems to be
asserting is that there is no need for a SIP. We disagree. We found the
SIP inadequate under the Act, and, thus, it is incumbent on the State
to submit an adequate SIP. Whether emissions in the area have gone down
since we issued our 1993 letter or since the State adopted the
stipulations for the SIP is irrelevant. Our concern under the Act must
be whether the federally approved and enforceable SIP meets the
requirements of the Act. Congress gave EPA the ultimate approval role
for SIPs.
(10) Comment: One commenter stated that damage done by sanctions
can not be undone. Because of offset sanctions, sources may avoid
projects, shut down or spend more money than is necessary (leaving
sources at a competitive disadvantage). Withholding highway funds could
cause a safety problem for people. Also, once a highway budget is lost
it is irretrievable. (See MSCC letter, document # IV.A-20, comment #
5F; MSCC letter, document # IV.A-19, comment # 113.)
Response: It is difficult to respond to comments which speculate
about what might happen in the future. At this point, we are deciding
not to apply sanctions. However, as indicated above, Congress intended
sanctions to be used to assure that SIPs and SIP revisions would be
developed on time, would provide adequate controls, and would otherwise
satisfy Act planning requirements. Applying sanctions may have adverse
effects. However, highway funds used for safety and environmental
projects cannot be withheld for sanctions applied under section 179 or
110(m) of the Act.
(11) Comment: One commenter stated that sanctions should not be
imposed because of a dispute between the State and Federal governments
regarding an interpretation of a regulation. The commenter stated
sanctions should not be imposed until the differences are resolved or
adjudicated. (See MSCC letter, document # IV.A-20, comment #'s 4D, 4E;
MSCC letter, document # IV.A-19, comment # 114.)
Response: We do not agree that sanctions should not be applied
merely because of a dispute between the State and EPA regarding an
interpretation of a regulation. In this particular case, we told the
State in 1996 that we could not
[[Page 22179]]
approve the plan based on its interpretation of the stack height
regulations. In 1998, the State submitted revisions to the plan knowing
that the plan would be disapproved in part.
C. Flares
We proposed to disapprove the SIP as it applies to the attainment
demonstration because of the lack of enforceable emission limitations
for flares. We also proposed to disapprove provisions of the SIP that
allowed certain gas streams at Cenex and ExxonMobil to be burned in the
flare.
Summary of Comments and Response
Eleven commenters submitted comments pertaining to our proposal
impacting flares. Seven of the commenters opposed and three supported
our proposed disapproval of the attainment demonstration for lack of
flare limitations. Two commenters opposed and two supported our
proposed disapproval of provisions that allowed certain gas streams at
Cenex and ExxonMobil to be burned in the flare. One commenter noted
that agencies across the country have struggled with flares.
We have considered the comments received and still believe it is
appropriate to disapprove the SIP as it applies to the attainment
demonstration for lack of flare emission limitations.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: Several commenters (State letter, document # IV.A-23,
comment # 3; YVCC letter, document # IV.A-29; Zaidlicz letter, document
# IV.A-30) stated that the attainment demonstration is incomplete
without flare limitations. Several commenters (State letter, document #
IV.A-23, comment # 3; Conoco letter, document # IV.A-28) stated that
the State's current flare provisions should be or have been sufficient.
Other commenters (Conoco letter, document # IV.A-24; ExxonMobil letter,
document # IV.A-28; MSCC letter, document # IV.A-19, comment #'s 55,
76; MSCC letter, IV.A-20, comment # 7; Cenex letter, document # IV.A-
26) stated we are mistaken in disapproving the attainment demonstration
because the SIP lacks flare emission limitations and that we did not
provide a valid reason for the proposed disapproval or why flares must
have specific emission limitations. One commenter (MSCC letter, IV.A-
20, comment #'s 7B, C and D) stated that our disapproval of the
attainment demonstration for lack of enforceable flare limitations even
though flares are modeled is in error and that the modeling of the
flares provides a small degree of conservatism in the modeling and is
an exercise of state discretion for determining the background SO2
concentrations.
Response: We continue to believe that the SIP as it applies to the
attainment demonstration is not approvable since it does not have
enforceable limitations on flares. Additionally, we believe our
rationale in the proposed approval (64 FR 40801 of our July 28, 1999
proposal) provided a simple and logical reason why the attainment
demonstration should not be approved and why flares must have emission
limitations. We have not reviewed the State's current flare provisions
because they were never submitted to us for review or approval.
However, we did review and comment on earlier versions of the flare
provisions that the State had adopted.
In the following documents we provided comments on earlier flare
provisions adopted by the State: December 15, 1994 letter from Douglas
M. Skie, Chief, Air Programs Branch, EPA, to Jeffrey Chaffee, Acting
Administrator, Air Quality Division, Montana Department of Health and
Environmental Sciences (see document # IV.C-17); April 19, 1995 letter
from Douglas M. Skie, Chief, Air Programs Branch, EPA, to Jeffrey
Chaffee, Administrator, Air Quality Division, Montana Department of
Health and Environmental Sciences (see document # IV.C-18); June 3,
1997 letter from Jack W. McGraw, Acting Regional Administrator, EPA, to
Mark Simonich, Director, Montana Department of Environmental Quality
(see document # II.C-8); March 6, 1998 letter from Richard R. Long,
Director, Air Program, EPA to Mark Simonich, Director, Montana
Department of Environmental Quality (see document # II.C-10); and June
5, 1998 letter from Richard R. Long, Director, Air Program, EPA to Mark
Simonich, Director, Montana Department of Environmental Quality (see
document # II.E-7).
(2) Comment: Several commenters (Conoco letter, document # IV.A-24;
American Petroleum Institute letter, document # IV.A-25; Cenex letter,
document # IV.A-26; ExxonMobil letter, document # IV.A-28; MSCC letter,
document # IV.A-19, comment # 55) stated that neither our regulations
(40 CFR 51.281) nor the Act (section 110(a)(2)(A)) require that all
control strategies in the SIP must be federally enforceable; State
enforceability is sufficient. One commenter (MSCC letter, document #
IV.A-20, comment # 7A) stated our proposed disapproval of the
attainment demonstration is in error since flare limitations exist on
the State level.
Response: We do not agree that some of the control strategies
adopted by the State do not need to be submitted to us and made part of
the federally approved SIP. The general air quality management
philosophy is that we establish NAAQS; States develop, and submit to
us, control programs to attain and maintain these NAAQS. We either
approve or disapprove these control programs and to the extent they are
approved they are legally enforceable by us and citizens under the
Act.\11\
---------------------------------------------------------------------------
\11\ See our TSD (document # III.B-1, at p. 5) and 64 FR 40791
at p. 40805 (document # III.A-2).
---------------------------------------------------------------------------
This philosophy is reiterated in the General Preamble, 57 FR 13497
(April 16, 1992) \12\ (document # II.A-15), at page 13567, right
column: ``[i]t is important to note that projections of the effect of
planned air pollution control measures contained in the SIP's are not
merely assumed but are enforced by regulations adopted as part of the
SIP. Therefore, if the control measures are not implemented
sufficiently to result in required reductions, the State or local
agency, or EPA, can take action to enforce implementation of the
regulations. This provides a means of achieving, at least in part, the
goal of attainment and further progress required in the Act.'' The
control measures cannot be enforced by citizens and us if the State
does not submit them as a SIP revision and we do not make them
federally enforceable by our approval of the SIP.
---------------------------------------------------------------------------
\12\ The General Preamble, a document we issued following the
1990 Clean Air Act Amendments, describes our preliminary views on
how we should interpret various provisions of title I of the Act.
---------------------------------------------------------------------------
Further, our discussion on the lack of flare emission limitations
in our TSD and proposed rulemaking \13\ provides citations in 40 CFR
part 51 to support the philosophy that all the control measures
necessary for attainment and maintenance of the NAAQS must be included
as part of the SIP.
---------------------------------------------------------------------------
\13\ See our TSD (document # III.B-1, at p. 37) and 64 FR 40791
at p. 40801 (document # III.A-2).
---------------------------------------------------------------------------
The commenters point to 40 CFR 51.281 and section 110(a)(2)(A) of
the Act as not requiring that every control strategy (relied on for
attainment and maintenance of the NAAQS) be included as part of the
federally approved SIP. The commenters state that State enforceability
of certain control strategies satisfies these provisions. We believe
the commenters are reading the Act and CFR incorrectly.
Section 110(a)(2)(A) of the Act says ``[e]ach implementation plan
submitted by the State under this Act shall be adopted by the State
after reasonable
[[Page 22180]]
notice and public hearing. Each such plan shall--(A) include
enforceable emission limitations and other control measures, means, or
techniques * * *, as well as schedules and timetables for compliance,
as may be necessary or appropriate to meet the applicable requirements
of the Act.'' There are several important ideas in this section that
the commenters are ignoring. First, the section presumes that the plan
is being submitted to us. The State enforceable provisions for flares,
which the commenters say meet section 110(a)(2)(A), have not been
submitted to us. Second, the plan that is submitted to us shall contain
enforceable emission limitations to meet the applicable requirements of
the Act, e.g., show attainment and maintenance of the NAAQS. If a plan
is lacking in certain control measures necessary for attainment, then
it does not meet section 110(a)(2)(A) of the Act. Finally, the
definition of ``applicable implementation plan,'' in section 302(q) of
the Act, supports the notion that the implementation plan is what is
submitted and approved by us. The implementation plan, under the Act,
does not consist of measures that are only enforceable by the State and
were not included in the submission to EPA.
Forty CFR 51.281 indicates that any emission limitations necessary
for attainment and maintenance of the NAAQS must be adopted as rules
and regulations and be enforceable by the State. The commenters rely on
the first sentence of this section as evidence that control measures
for attainment and maintenance need only be State enforceable and do
not need to be submitted as part of the plan. However, the commenters
are ignoring the second sentence of this section which says that
``[c]opies of all such rules and regulations must be submitted with the
plan.'' The definition of ``plan,'' in 40 CFR 51.100(j), supports the
notion that the implementation plan is what is submitted and approved
by us. Forty CFR 51.281 and 40 CFR 51.100(j), read together, support
the theory that all control measures relied on for attainment and
maintenance of the NAAQS must be submitted as part of the plan. The
implementation plan, under 40 CFR part 51, does not consist of
unsubmitted measures that are only State-enforceable.
(3) Comment Several commenters (Conoco letter, document # IV.A-24;
Cenex letter, document # IV.A-26; ExxonMobil letter, document # IV.A-
28) stated that since our modeling guidance in 40 CFR part 52, appendix
W, footnote (e) of section 9.1.2 does not require modeling of
malfunctions (these are not normal operations and not considered in
determining allowable operations when modeling), emissions from flares
during operations that are not normal (startup, shutdown, malfunctions
and process upsets) should not be considered in determining the
allowable emissions when modeling relative to the SIP.
Response: We agree with the commenters that our modeling guideline
in 40 CFR part 52, appendix W, section 9.1.2, footnote (e) indicates
that malfunctions are not modeled to determine the allowable
limitation. We do not agree with commenters that our modeling guideline
explicitly or implicitly does not require the modeling of emissions
that result from operations that are not normal and routine or that
operation of flares at the Billings/Laurel sources is not normal and
routine, at least in part. The 150 lbs/3-hr flare emission limitation
used in the attainment modeling does not reflect malfunction emissions,
but rather emissions from routine operations at the refineries. Bob
Raisch's September 28, 1995 letter to us (document # II.B-18, first
page of the enclosure to the letter) says ``[t]he Department and each
of the refineries estimated that amount of sulfur dioxide which is
emitted from each flare during routine operations of the refinery.''
Tim Schug's January 22, 1999 letter to us (document # IV.C-12)
indicates that a flare is a safety device that is used to manage
combustible gases. Mr. Schug also indicates that ``[i]n addition, small
and continuous quantities of gases may routinely be directed to the
flare.'' Conoco's comments on our proposal (document # IV.A-24) says
``[r]outine emissions are expected to be less than 150 lbs SO2 per 3-
hour period * * *'' Therefore, it appears that the State and industry
agree that emissions from the flares occur on a routine basis.
Thus, for purposes of this action, we need not reach the issue of
whether non-routine startups, shutdowns, etc. should be modeled. In
this case, the State modeled routine flare emissions assuming they
would be limited to 150 lbs of SO2 per 3-hour period, but did not
include corresponding emission limits in the SIP submitted to us. This
is the basis for our disapproval of the attainment demonstration for
lack of flare emission limitations.
(4) Comment One commenter (Conoco letter, document # IV. A-24)
referred to our concern that if we approved the SIP without making the
State-only requirements federally enforceable, the sources could direct
emissions from other process units to the flares to avoid violating any
emission limitation or other requirement. Further, we indicated that it
did not appear that sources could be penalized through the SIP if such
circumvention occurred. Conoco stated that these concerns are misplaced
since Montana Regulations and the ``Other Minor Sources'' provision of
the stipulations prevent this. Two other commenters (YVCC letter,
document # IV.A-29; Zaidlicz letter, document # IV.A-30) stated flares
could be used to circumvent other emission limitations.
Response: In our proposed action we indicated that if there were no
emission limitations on flares it appeared that sources could direct
emissions from other process units to the flare to avoid violating an
emission limitation or other requirement. We indicated that it did not
appear that sources could be penalized through the SIP if such a
circumvention occurred. One commenter stated our concern was misplaced
because of existing State regulations and the ``Other Minor Sources''
provisions in the SIP.
The ``Other Minor Sources'' provision in the SIP does not alleviate
our concern because this provision addresses the emissions of sulfur
bearing gases from other minor sources which are not otherwise subject
to the SIP. Our concern assumes that emissions being diverted to the
flare are otherwise subject to the SIP.
We assume that the commenter is referring to the State's
circumvention regulation as ``existing State regulations.'' The State's
circumvention regulation, approved into the SIP, states, ``(1) No
person shall cause or permit the installation or use of any device or
any means which, without resulting in reduction in the total amount of
air contaminant emitted, conceals or dilutes an emission of air
contaminant which would otherwise violate an air pollution control
regulation.'' Based on the title, it seems that the State's
circumvention regulation should address the concern we raised. However,
after further review of the regulation we are not convinced that it
could prevent sources from directing emissions from other process units
to the flare to avoid violating an emissions limitation or other
requirement.
Therefore, we continue to believe that establishing emission
limitations on flares or some other enforceable mechanism is necessary
to prevent sources from redirecting emissions to the flare in order to
avoid violating emission limitations elsewhere.
(5) Comment: Several commenters (Conoco letter, document # IV.A-24;
American Petroleum Institute letter, document # IV.A-25; Cenex letter,
[[Page 22181]]
document # IV.A-26; ExxonMobil letter, document # IV.A-28; MSCC letter,
document # IV.A-19, comment #'s, 55, 75, 76, 118; MSCC letter, document
# IV.A-20, comment # 7F; Goetz letter, document # IV.A-18, exhibit C)
stated that other SIPs do not limit emissions from flares, that this
SIP should not either, and that our action here is arbitrary. One
commenter (MSCC letter, document # IV.A-20, comment #'s 7E, 7F) stated
our proposal to disapprove the attainment demonstration was in error
because flare limitations are not required federally and flares are not
stacks. One commenter (Goetz letter, document # IV.A-18, exhibit C)
found that the Utah, Washington and Wyoming SIPS do not require
limitations on flares. Finally, one commenter (MSCC letter, document #
IV.A-19, comment #'s 77, 118) stated that if we determine that the
Billings SIP is inadequate because of the lack of flare limitations we
need to determine that all SIPs are inadequate and do a national
rulemaking.
Response: We do not agree that just because other SIPs may not have
limitations on flares that the Billings/Laurel SO2 SIP should not
either. We believe that when an area has been determined to not be
attaining the NAAQS, it is reasonable to apply extra measures to assure
that the area attains and maintains the NAAQS. Since the State
identified a concern with flare emissions and included the emissions in
the attainment demonstration, we believe it is reasonable to make
restrictions on flares federally enforceable. With respect to Utah, the
commenters are correct that the federally approved PM-10 SIP for Salt
Lake and Utah Counties does not contain SO2 flare emission limits.\14\
We have identified this as an issue with the Utah PM-10 SIP and are
working with the State to address the issue. Wyoming does not contain
any SO2 nonattainment areas, and the one PM-10 nonattainment area,
Sheridan, does not contain any refineries. Washington does not have any
SO2 nonattainment areas. However, the Tacoma PM-10 nonattainment area
in Washington does contain a refinery (see document #IV.C-14). EPA
found in our October 12, 1994 (59 FR 51506) and October 25, 1995 (60 FR
54599) approvals of the PM-10 SIP for Tacoma that it is unlikely that
precursors of PM-10 contribute significantly to PM-10 levels which
exceed the NAAQS in that area. PM-10 precursor emissions (SO2) were not
controlled as part of this SIP.
---------------------------------------------------------------------------
\14\ In PM-10 nonattainment areas, the control requirements
applicable to major stationary sources of PM-10 also apply to major
stationary sources of PM-10 precursors unless we determine such
sources do not contribute significantly to PM-10 levels in excess of
the NAAQS in that area (see section 189(e) of the Act). The General
Preamble (document # II.A-15) contains guidance addressing how EPA
intends to implement section 189(e) of the Act (see 57 FR 13539-
13540 and 13541-13542). In the Utah PM-10 SIP, SO2 emissions at
sources were controlled because SO2 is a precursor of PM-10.
---------------------------------------------------------------------------
Therefore, although commenters cite specific examples of states
near Montana that do not limit SO2 emissions from flares, we believe
the situation in the Billings/Laurel area is sufficiently different to
warrant the establishment of SO2 limitations on flares.
For the same reasons stated above, we do not agree that we need to
do a national rulemaking to require that all SIPS contain limitations
on flares.
Finally, we do not agree that flare limitations are not required on
a federal level. What is required on a federal level are emission
controls that will assure attainment of the NAAQS. In this particular
case, since the attainment demonstration assumes flare emissions were
controlled we believe the SIP should contain federally enforceable
emission limitations on flares. With respect to the comment that flares
are not stacks, the commenter is correct in that our definition of
stack in 40 CFR 51.100(ff) indicates that flares are not included.
However, just because an emission point is not a stack by definition
does not mean that the emission point should not be controlled. There
are numerous examples of fugitive emissions, which are not emitted from
stacks, being controlled in SIPS. See, for example, the East Helena
Lead SIP which was approved at 66 FR 32760 (June 18, 2001); the SIP
establishes emission limits and work practices for loading, unloading
and movement of material containing lead, for emissions from buildings,
and for emissions from roads and parking lots on and off the facility
property.
(6) Comment: Several commenters (Conoco letter, document # IV.A-24;
Cenex letter, document # IV.A-26; MSCC letter, document # IV.A-20,
comment # 7G) stated that instead of disapproving the SIP, flare
emissions should be removed from the attainment demonstration. One
commenter (MSCC letter, document # IV.A-20, comment # 7G) stated that
flare emissions should be included with other background sources.
Response: We do not agree that the appropriate way to address flare
emissions is to ``sweep them under the carpet'' or incorporate them
with background sources. As mentioned above, it is widely accepted that
routine emissions occur at flares. The State was concerned enough about
these emissions that it chose to regulate them at the State level and
considered them in the attainment demonstration. We believe that
turning our back on an issue simply because it is difficult to address
is not appropriate under the Act. The Act presumes that states will
develop an appropriate mix of controls to protect air quality. The
State identified the flares as an attainment issue. If the flares are
not limited by enforceable limitations, attainment will not be assured.
(7) Comment: Several commenters (American Petroleum Institute
letter, document # IV.A-25; Cenex letter, document # IV.A-26; Montana
Petroleum Association letter, document # IV.A-27; MSCC letter, document
# IV.A-19, comment #'s 55, 76) stated that flares are primarily
emergency relief devices and limiting flares puts a refiner in an
untenable position of having to choose between possible limitation
violations or endangering the plant or its workers. These commenters
also stated that flare use is essential and no reasonable alternative
exists.
Response: Our proposed action is not intended to jeopardize the
safety of refineries, their workers, or neighbors. Our SIP policy \15\
has long recognized that imposing penalties for violations of emission
limitations for sudden and unavoidable malfunctions caused by
circumstances entirely beyond the control of the owner or operator may
not be appropriate. States and EPA have the ability to exercise
enforcement discretion to refrain from taking enforcement action in
these circumstances.
---------------------------------------------------------------------------
\15\ See document # IV.C-13, September 20, 1999 memorandum
entitled ``State Implementation Plans: Policy Regarding Excess
Emissions During Malfunctions, Startup, and Shutdown.'' This policy
updates previous EPA policy, dating back to 1982, on this issue.
---------------------------------------------------------------------------
However, we are not convinced that flare use is always essential or
that no reasonable alternative exists. We know that other refineries,
either because of enforcement action or a company decision, have
reduced flaring through better operation and maintenance procedures
throughout the refinery and/or by installing flare gas recovery systems
to compress and recycle to the gas plant(s), gases that had previously
been sent or released to the flare. See EPA's Enforcement Alert
entitled ``Frequent, Routine Flaring May Cause Excessive, Uncontrolled
Sulfur Dioxide Releases,'' Volume 3, Number 9, EPA 300-N-00-0014
(revised), October 2000 (document # IV.C-72).
(8) Comment: Several commenters (American Petroleum Institute
letter,
[[Page 22182]]
document # IV.A-25; Goetz letter, document # IV.A-18, exhibit C; MSCC
letter, document # IV.A-19, comment #'s 55, 75) stated that since
measuring flow and concentration of hydrogen sulfide of the gas stream
flowing to the emergency flare is very difficult, the flares should not
be controlled.
Response: We do not agree. First, we are not convinced that
measuring flow and content of the flare is impossible. We are
evaluating potential methods for measuring flare flow and content in
preparation of our FIP. Second, other means are available to determine
SO2 emissions from flares apart from measuring flare flow and content.
To meet the ``State-only'' requirements for flares it appears that the
refineries and MSCC are calculating SO2 emissions based on good
engineering judgement.
(9) Comment: Several commenters (American Petroleum Institute
letter, document # IV.A-25; Cenex letter, document # IV.A-26;
ExxonMobil letter, document # IV.A-28; Montana Petroleum Association
letter, document # IV.A-27; Conoco letter, document # IV.A-28) stated
our action is precedent-setting and more data should be collected to
justify the costs and the benefits of imposing emergency flare
limitations.
Response: At this point we are not imposing flare limitations; we
are disapproving the attainment demonstration for lack of flare
emission limitations.
(10) Comment: Several commenters (Cenex letter, document # IV.A-26;
American Petroleum Institute letter, document # IV.A-25; MSCC letter,
document # IV.A-19, comment # 75; Conoco letter, document # IV.A-28)
stated the emissions from flares are inconsequential based on the
potential to emit levels in the SIP modeling and have little ambient
impact. Two commenters (YVCC letter, document # IV.A-29; Zaidlicz
letter, document # IV.A-30) stated SO2 emissions from flaring are
significant. Other commenters (ExxonMobil letter, document # IV.A-28;
American Petroleum Institute letter, document # IV.A-25; Conoco letter,
document # IV.A-28) stated that SO2 emissions and ambient
concentrations are at an all-time low and the imposition of
extraordinary flare limitations is unnecessary.
Response: We do not agree that flare emissions are inconsequential
and have little ambient impact.
The State modeled emissions from flares at 150 lbs of SO2/3-hours.
This 3-hour modeled value equates to 219 tons of SO2/year for each
source (((150 lbs SO2/3-hrs) * (8 3-hr periods/day) * (365 days/year))/
(2000 lbs/ton)). A major source in a nonattainment area, under 40 CFR
section 51.165, is a source that emits 100 tons per year or more of a
pollutant subject to regulation under the Act. Under 40 CFR section
51.166, a major source in an attainment area, is a source that emits
100 tons per year or more of a pollutant subject to regulation under
the Act if the source is a listed source category (refineries are a
listed source category) and 250 tons per year or more of a pollutant
subject to regulation under the Act if it is not a listed source
category. Under the Title V operating permit regulations, 40 CFR
section 70.2, a major source is a source that emits or has the
potential to emit 100 tons per year or more of any pollutant.
Therefore, based on our regulations, the modeled emissions from flares
at each source, in and of themselves, are considered major. Also, as
part of the attainment demonstration, the State assumed each of the
refineries and MSCC had one flare; the cumulative flare emissions from
all sources is 876 tons of SO2/year. We do not think flare emissions
are inconsequential.
Also, there is the real possibility that flares emit more than the
modeled SO2 level. Following its flare velocity and energy performance
test, Conoco estimated flare emissions from the flare header at its
Billings refinery at approximately 91 lbs of SO2/hour (see document #
IV.C-2). This is equivalent to 399 tons of SO2/year.
Regarding the ambient impact of flare emissions, Bob Raisch's
September 28, 1995 letter to us (document # II.B-18, first page of the
enclosure to the letter) indicates that ``[t]he inclusion of routine
flare emissions actually required lowering of the emission limitations
at other sources within the refinery.'' Based on this statement, we
believe that flares do have significant ambient impact.
(11) Comment: One commenter (Cenex letter, document # IV.A-26)
stated that over-reliance on or misapplication of three of our policy
memoranda pertaining to excess emissions during startup and shutdown
(i.e., the Bennett/Rasnic memos) has contributed to our concerns about
the flare issue. Another commenter (MSCC letter, document # IV.A-19,
comment #'s 55, 75) stated we cannot apply startup, shutdown and
malfunction policy to events that cannot reasonably be controlled; that
flares must be used during maintenance activities and neither industry
nor the State agree with our interpretation that startup, shutdown and
malfunction are avoidable.
Response: We do not agree that our flare concerns stem from any
over-reliance on or misapplication of our policy pertaining to excess
emissions during startup, shutdown and malfunction. Our proposed
disapproval of the SIP stems from the fact that gas streams are sent
routinely to the flare to be burned, causing SO2 emissions from flares.
The attainment demonstration assumes that flares are limited yet the
SIP submitted by the State does not contain limitations on flares.
Therefore, we believe that attainment of the SO2 NAAQS cannot be
assured without limitations on flares.
Earlier versions of the State's SIP (those submitted prior to the
July 1998 submittal) contained exemptions from the flare limitations
for startups, shutdowns and malfunctions. We were concerned about the
automatic exemptions to emission limitations because attainment and
maintenance of the SO2 NAAQS cannot be assured if exemptions to
limitations are allowed. However, since the State removed the flare
provisions from the SIP submitted to us, our concerns about startup,
shutdown and malfunction were mooted. Note that our policy on excess
emissions during startup, shutdown and malfunctions has been reaffirmed
and reissued (document # IV.C-13).
(12) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #75) stated we insisted that the State model flares and that we
objected long after the State made clear it would not regulate flare
emissions.
Response: We do not recall requiring the State to model flares. Our
recollection is that we deferred to the State's judgement as to which
flares should be explicitly modeled.
Also, EPA did not wait until the last minute to voice concerns
about flares. Our initial comments on the flare provisions date back to
December 1994. In the following documents we provided comments on the
flare provisions: December 15, 1994 letter from Douglas M. Skie, Chief,
Air Programs Branch, EPA, to Jeffrey Chaffee, Acting Administrator, Air
Quality Division, Montana Department of Health and Environmental
Sciences (see document # IV.C-17); April 19, 1995 letter from Douglas
M. Skie, Chief, Air Programs Branch, EPA, to Jeffrey Chaffee,
Administrator, Air Quality Division, Montana Department of Health and
Environmental Sciences (see document # IV.C-18); June 3, 1997 letter
from Jack W. McGraw, Acting Regional Administrator, EPA, to Mark
Simonich, Director, Montana Department of Environmental Quality (see
document # II.C-8); March 6, 1998 letter from
[[Page 22183]]
Richard R. Long, Director, Air Program, EPA to Mark Simonich, Director,
Montana Department of Environmental Quality (see document # II.C-10);
and June 5, 1998 letter from Richard R. Long, Director, Air Program,
EPA to Mark Simonich, Director, Montana Department of Environmental
Quality (see document # II.E-7).
(13) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #75) stated the State carefully considered this and determined
flares should not have federal limitations. Another commenter (McGarity
letter, document # IV.B-1) stated that regulating emissions from flares
is a technical area that state agencies around the country have
struggled with. There are many valid technical difficulties associated
with monitoring and controlling emissions from flares.
Response: We do not agree with the commenter that the State
carefully considered the flare issue and determined flares should not
have federal limitations. Based on the State's comments submitted in
response to our proposed action (see document # IV.A-23), the commenter
is not representing the State's position accurately.
In its comments to our proposed action (see document # IV.A-23,
comment #3) the State said, ``[t]he State agrees with EPA that the SIP
is incomplete without enforceable emission limitations applicable to
flares, and that such limitations should correspond to the emission
rates used in the attainment demonstrations. However, after significant
effort to address the issue, the State was unable to find a workable
solution that would meet EPA's concerns.''
We agree with the commenter that it appears that state agencies
across the country have struggled with limiting emissions from refinery
flares. However, as indicated in response to comment # 7, above, it
appears that there have been recent strides in reducing and measuring
emissions from flares.
(14) Comment: Two commenters (Cenex letter, document # IV.A-26;
ExxonMobil letter, document # IV.A-28) stated that we should not
disapprove the provisions that allow the burning of certain gas streams
at Cenex and ExxonMobil in the flare because ExxonMobil and Cenex have
a way to account for the emissions and under the State-only provisions
the flare emissions are limited. Two commenters (YVCC letter, document
# IV.A-29; Zaidlicz letter, document # IV.A-30) agree that sour water
stripper emissions, if burned in the flare would be unregulated. These
commenters stated that sour water stripper emissions should be sent to
a sulfur recovery unit instead of burned in a combustion unit.
Response: We proposed to disapprove provisions of the SIP that
allow Cenex and ExxonMobil to burn sour water stripper emissions in the
flare (in Cenex's exhibit sections 3(B)(2) and 4(D), only as they apply
to flares, and in ExxonMobil's exhibit sections 3(E)(4) and 4(E), only
as they apply to flares). Commenters stated we should not propose to
disapprove these provisions since Cenex and ExxonMobil have methods to
determine SO2 emissions when these specific gas streams are burned in
the flare. Although we understand that the SIP provides a means to
determine SO2 emissions when these gas streams are burned in the flare,
the flare does not have any limitations that are enforceable under the
federal SIP. Therefore, although the SO2 emissions from the gas streams
burned in the flare can be accounted for, the emissions are not
limited. We believe that attainment of the SO2 NAAQS can not be assured
without enforceable limitations on the flare. We continue to believe
that the provisions that allow the burning of sour water stripper
emissions in Cenex and ExxonMobil's flare should be disapproved.
However, in this action we cannot require that the sources be
prohibited from burning sour water stripper emissions in a combustion
unit or that they send the sour water stripper emissions to the sulfur
recovery unit. We can only approve or disapprove the SIP as submitted
by the State. Likewise, we cannot create any new requirements by our
action on the SIP.
(15) Comment: Several commenters (Conoco letter, document # IV.A-
24; Montana Petroleum Association letter, document # IV.A-27;
ExxonMobil letter, document # IV.A-28) recommend that we conditionally
approve, rather than disapprove, the SIP as it applies to flares, so
that differences between us and the State can be worked out.
Response: We cannot conditionally approve the SIP with respect to
flares unless the Governor of Montana commits to revise the SIP to
address our concerns. See section 110(k)(4) of the Act. At this time we
have not received such a commitment.
D. Dispersion Modeling
Based on our regulations and the characteristics of the Guideline
models in appendix W, in our proposed rulemaking we found that the
State of Montana used the appropriate computer models for analyzing the
adequacy of the existing SIP and for setting emission limitations in
the SIP revision to protect the SO2 NAAQS. However, for several reasons
discussed in our proposed rulemaking and TSD we proposed to disapprove
the attainment demonstration.
Summary of Comments and Response
Two commenters believed that the dispersion modeling that formed
the basis for both the 1993 letter and the attainment demonstration was
invalid. Two commenters also proposed using other models for attainment
demonstration purposes. One commenter wanted us to acknowledge that
there were two modeling attainment demonstrations; one for the Laurel
area and one for the Billings area.
We have reviewed the comments received and still believe that
Montana used the appropriate computer models for analyzing the adequacy
of the existing SIP and for setting emission limitations in the SIP
revision to protect the SO2 NAAQS. We also acknowledge that there are
two modeling demonstrations.
The following is a summary of the comments received and our
response to the comments:
1. Validity of the Computer Models
(a) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment # 1; MSCC letter, document # IV.A-20, comment # 8.B; Goetz
letter, document # IV.A-18, exhibit D, comment # III, p. 43) stated
that computer modeling of SO2 concentrations in the Billings/Laurel
area was invalid because the models used by the State were screening
models that over-predict concentrations. One of the commenters (MSCC
letter, document # IV.A-20, comment # 3D) stated that EPA's conclusion
that the existing SIP was inadequate was not based on the output of an
Appendix A model.
Response: We do not agree with the commenters that only screening
models were used. We also disagree with the assertion that EPA's SIP
Call was not based on the output of an appendix A model. Appendix A to
appendix W of part 51, Summaries of Preferred Air Quality Models,
provides key features of refined air quality models preferred for
specific regulatory applications. In the modeling studies for both the
SIP Call and the attainment demonstration of the revised SIP, an
analysis was performed using the modeling techniques and data bases
recommended in our ``Guideline on Air Quality Modeling (Revised)''
(``EPA Guideline'' or ``Guideline''). Our Guideline is found in 40 CFR
part 51, appendix W.
Two Guideline models were used. For ``simple terrain'' below the
tops of stacks, the ISC2 model was used. ISC2,
[[Page 22184]]
a revised version of ISC, is a refined dispersion model that is
preferred by EPA for a wide range of regulatory applications in simple
terrain. See 40 CFR part 51, appendix W, section 4.1.a and appendix A
to appendix W. ISC2 was listed in appendix A to the Guideline at the
time the modeling analyses for the Billings/Laurel SIP were performed.
(The current version of the Guideline lists ISC3 as a preferred model.
See 40 CFR part 51, appendix A to appendix W, A.5. ISC3 is a more
refined version of ISC2 and did not exist at the time of the modeling
analyses for the Billings/Laurel area.) For terrain above the tops of
stacks, COMPLEX I was used. This is a preferred screening technique,
which is incorporated into ISC2 to evaluate concentrations of SO2 in
``complex terrain.'' See appendix W at section 5.2.1. A screening model
may over-predict concentrations or may under-predict concentrations in
comparison to concentrations that will actually occur in the future.
COMPLEX I is not an appendix A model; however, as mentioned above, it
is part of ISC2/ISC3 which is an appendix A model. Section 5.2.1.a of
the Guideline indicates that for complex terrain any of the identified
screening techniques (including COMPLEX I) may be used consistent with
the needs, resources and available data of the user. Section 5.2.2.a of
the Guideline indicates that when results of the screen analysis
demonstrate a possible violation of the NAAQS or the controlling PSD
increments, a more refined analysis may need to be conducted. For
reasons discussed later in this section, a more refined model could not
be applied for complex terrain in the Billings/Laurel area.
(b) Comment: One commenter, (MSCC letter, document # IV.A-19,
comment # 6) stated that modeling is required under the Act only for
reports to Congress and for prediction of the effect of emissions
(presumably from new sources)--not for determination of SIP adequacy.
Response: The statutory provision that authorizes the use of
modeling is not limited as the comment suggests. Section 110(a)(2)(K)
of the Act requires that all SIPs must
provide for--
(i) the performance of such air quality modeling as the
Administrator may prescribe for the purpose of predicting the effect
on ambient air quality of any emissions of any air pollutant for
which the Administrator has established a national ambient air
quality standard, and
(ii) the submission, upon request of data related to such air
quality modeling to the Administrator.
By its terms, this provision does not limit the use of modeling to
making reports to Congress or permitting new sources. An essential
function of air quality modeling is determination of SIP adequacy; so,
too, is the establishment of emission limitations for existing sources
as part of SIP development. Air quality modeling is, in fact, the only
reliable means of determining the adequacy of an SO2 SIP to protect the
NAAQS, as will be explained in more detail below.
(c) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment # 107; Goetz letter, document # IV.A-18, exhibit D, comment #'s
III.C, p. 46, and III.F, p. 55) stated that the models should have been
validated in the Billings/Laurel area.
Response: As EPA Guideline models, ISC2 and COMPLEX I have been
standardized and validated through scientific study and application in
many areas of the country. We authorize the direct use of Guideline
models in regulatory applications such as SIP Calls and SIP
development, ``without a formal demonstration of applicability'' in the
local area, as long as the models are used as directed in appendix W.
See 58 FR 38816, 38825 (July 20, 1993) (rulemaking by which our
modeling guideline was codified as a regulatory requirement).
Validation of the model in the local area where it will be applied
is not required for any of the standardized Guideline models or
approved screening techniques. On-site validation is required only for
alternative models, which are proposed by industry or states to be used
in lieu of our Guideline model. Industry in the Billings/Laurel area
and the State of Montana did not propose to collect the necessary air
quality/meteorological data and perform the statistical performance
evaluation and comparison of models that would be necessary to apply an
alternative model for the Billings/Laurel area SIP revision. If an
alternative model could be shown to perform better than ISC2/COMPLEX I,
it would yield somewhat more accurate predictions of ambient impacts of
SO2 emissions, but such an effort would require a minimum of one year
of on-site data gathering and considerable expense in research costs.
The results of such a study could dictate the need for either higher or
lower emission control limitations.
(d) Comment: Two commenters (MSCC letter, document # IV.A-20,
comment #'s 3.G and 3.S; Goetz letter, document # IV.A-18, exhibit D,
comment # III.C, p. 46) stated that a prior agreement (1977
Stipulation) required the State to validate any models used in the
Billings/Laurel area, but that the State's 1984 studies showed that the
model used was ``invalid'' for the area. The model determined to be
invalid in 1984 is being used in the Billings/Laurel area now. The MDEQ
has completed a ``performance evaluation'' of the model, not a
validation study. One of the commenters (Goetz letter, document # IV.A-
18, comment # III, p. 43) stated that, in response to a SIP Call based
on defective modeling, the State developed a SIP based on defective
modeling.
Response: Although our regulations do not require local validation
of the models (see D.1.(c), above), MDEQ did perform an evaluation
study in the Billings/Laurel area in 1994, using monitoring data to
determine how accurately the models were performing. The evaluation
study compared monitored data with modeled predictions for the same
site. The evaluation study showed that model performance by ISC2 and
COMPLEX I exceeded the levels of accuracy that we expected for this
application and exceeded the performance of the models in similar tests
elsewhere in the country. We do not believe the SIP Call and
subsequently developed SIP are based on defective modeling. See also
the response to Comment (g), below.
(e) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.F, p. 56) stated that the 1994 evaluation
study showed a failure to correlate modeled results and monitored data
at 13 of 88 data points.
Response: The evaluation study showed that the model passed the
statistical test at 75 data points, an acceptable level. Moreover, the
study showed that the ISC2/COMPLEX I model predicted concentrations
within plus or minus 20 percent of monitored levels. This is an
unusually high correlation. We would expect errors in the highest
estimated concentrations of plus or minus 10 to 40 percent to be
typical for models of this type. See the Guideline on Air Quality
Models, appendix W at 10.1.2. (We would not expect the study to predict
concentrations within a ``factor of two,'' the correlation which the
commenter (Goetz letter, document # IV.A-18, exhibit D, comment #
III.A, p. 44) attributed to us as an acceptable test of model
performance.) Where the model failed the test, MDEQ attributed the
discrepancy to an underestimate of actual SO2 emissions at Cenex, not a
flaw in the model itself.
(f) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.F) also stated that ISC2
[[Page 22185]]
should have been evaluated in elevated terrain near the tops of stacks.
Response: Such an evaluation might be possible in an area that has
a single source with only one or a few stacks. Because of the large
number of stacks in Billings, all at different elevations, it would be
impossible to establish a single value for ``stack-top'' elevation;
such a study would not be meaningful. In any case, a local validation
study is not required for a nationally validated model, such as ISC2/
COMPLEX I.
(g) Comment: Two commenters (MSCC letter, document # IV.A-20,
comment #; Goetz letter, document # IV.A-18, exhibit D, comment #
III.C, p. 46) stated that MDEQ conducted a validation study of COMPLEX
I in the Billings/Laurel area in 1983-84 and that the model failed
miserably.
Response: Having reviewed the test report (see document # IV.A-17,
exhibit # 88), we conclude that this was not a true validation study. A
true validation study of COMPLEX I would involve placing large numbers
of temporary monitors, called ``sampling bags,'' on nearby hillsides
and measuring the impacts of tracer gases emitted from individual
stacks to determine which stacks are impacting which areas of elevated
terrain. The data collected from the array of monitors would then be
compared with modeled predictions based on real-time measured emissions
from all the sources. We conducted studies of this kind, at great
expense, to validate COMPLEX I and other dispersion models on a
national level in the 1980's. Our validation studies showed that
COMPLEX I did not perform as well as refined models, but performed well
enough to serve as a screening tool for use in valley areas with
multiple stacks, like the Billings/Laurel area.
The State study in 1983-84 used the existing limited monitoring
network of seven monitors, few of which were located in elevated
terrain. Tracer gases were not employed, and SO2 emissions estimates
for the Billings sources were unreliable at the time. The MDEQ's
conclusion that COMPLEX I was not appropriate for modeling sources in
Billings, as reported by one commenter (Goetz letter, document # IV.A-
18, exhibit D, comment III.C, p. 46), was based on an inadequate
evaluation and is not pertinent to the validity of the SIP Call or the
attainment demonstration.
(h) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment III.E, pp. 51-54) cited case law to support his
assertion that the computer models that were used to develop the SIP
for the Billings/Laurel area required on-site validation.
Response: The cases cited in the comment are concerned with the
less reliable models that predated the standardized Guideline models
now incorporated into appendix W. For example, in State of Ohio v.
United States EPA, 784 F.2d 224 (6th Cir. 1986), the Sixth Circuit held
that EPA arbitrarily relied on the CRSTER computer model to set air
pollution limitations for two electric utility plants on Lake Erie. The
CRSTER model, now obsolete, was used to predict concentrations of SO2
over the Lake under unusual meteorological and topographic conditions
for which the model had not been validated. The facts in the Ohio case
distinguish it from the Billings/Laurel area SO2 SIP. Unlike the CRSTER
model, the models used for the Billings/Laurel area have performed well
in similar applications elsewhere in the country involving similar
topographic features and similar meteorological characteristics. There
are no unusual conditions in the Billings/Laurel area that would tend
to undermine the reliability of ISC2 and COMPLEX I; on-site validation
would be redundant.
(i) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 8.A) stated that models must take into account the unique
characteristics of the area where they are used and that modeling for
the Billings/Laurel SIP failed to take the area's unique
characteristics into account.
Response: Modeling for the SIP considered all Billings/Laurel area
sources, stack parameters, building dimensions, emission rates, terrain
elevations, and five years of continuous meteorological data collected
at a representative location. We believe that this data set adequately
accounts for the unique characteristics of the area.
(j) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.E. p. 52) quoted the State of Ohio opinion as
supporting the position that ``EPA's own guidelines'' recognize the
importance of validating a model with monitored data from the local
area.
Response: The ``guidelines'' referred to have been superseded. The
court was referring to the 1978 version of the EPA Guideline on Air
Quality Models 6, which did encourage local validation. This version
was superseded in 1986 by an extensive revision of the Guideline. At
that time, we conducted national validation studies on all existing
computer models and replaced some of them with more reliable models. In
1993, the revised Guideline was incorporated directly into 40 CFR part
51 as appendix W. See 58 FR 38816 (July 20, 1993).
(k) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.E. p. 53-54) also cited Cincinnati Gas &
Electric Co. v. Environmental Protection Agency, 578 F.2d 660 (6th Cir.
1978) and Columbus & Southern Ohio Elec. Co. v. Costle (638 F.2d 910
(6th Cir. 1980) as indicating the necessity for on-site validation.
Response: In these cases, the Sixth Circuit remanded regulatory
decisions to EPA when the agency's model (MAXT-24) used assumptions
that were successfully challenged by local studies. The MAXT-24 model,
again, has been superseded nationally and is not an EPA Guideline
model. These cases do not discredit the application of nationally
validated Guideline models, ISC2 and COMPLEX I, in the Billings/Laurel
area.
2. Effect of ``Contradictory'' Monitoring Data
(a) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment # 1; MSCC letter, document # IV.A-20, comment #'s 3.H and 3.I;
Goetz letter, document # IV.A-18, exhibit D, comment #'s III.A and
III.B, pp. 44-45) stated that ambient air monitoring is more accurate
than computer modeling and that monitoring data for the Billings/Laurel
area do not support the models' predicted violations of the SO2 NAAQS.
One commenter (MSCC letter, document # IV.A-19, comment # 119)
suggested that rather than issuing a SIP Call, we should have
questioned how our models or the State's monitors could be so far
wrong.
Response: Monitoring is not more accurate than computer modeling,
except for determining ambient concentrations under real-time
conditions at a discrete location. Monitoring is limited in time as
well as space. Monitoring can only measure pollutant concentrations as
they occur; it cannot predict future concentrations when emission
levels and meteorological conditions may differ from present
conditions. Computer modeling, on the other hand, can analyze all
possible conditions to predict concentrations that may not have
occurred yet but could occur in the future. As stated in the Guideline
on Air Quality Models (``the Guideline'') ``[m]odeling is the preferred
method for determining emission limitations for both new and existing
sources. When a preferred model is available, model results alone
(including background) are sufficient.'' 40 CFR part 51, appendix W,
section 11.2.2. In the usual case, regulators may rely on the results
of modeling and are not required to
[[Page 22186]]
consider measured data from local ambient monitoring.
(b) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.A, p. 44) stated that monitoring data may
reasonably be used as an acceptable technique to demonstrate that the
air quality in a region is being protected; monitoring data are facts,
while models use assumptions.
Response: The Guideline states, ``Due to limitations in the spatial
and temporal coverage of air quality measurements, monitoring data
normally are not sufficient as the sole basis for demonstrating the
adequacy of emission limits for existing sources.'' Forty CFR part 51,
appendix W, section 1.0.b. The use of measured data in lieu of model
predictions for SIP development is discouraged, because it is
impossible to capture worst case conditions, for either emission levels
or meteorology, with only a few monitors. Monitored data may be used in
certain, limited circumstances and only if monitors are located at
points of maximum concentration. See id. at section 11.2.2. Even then,
locations of maximum concentration may not remain the same, but may
change from year to year in response to changes in emission patterns
and emission rates from existing sources, installation of new emission
sources, and meteorological variability.
Even the most extensive monitoring network does not represent
future concentrations of pollutants and thus cannot predict future
violations. Modeling, on the other hand, can predict for all possible
conditions and can show how well the emission limitations in the SIP
will protect air quality under future conditions. Modeling assumes the
maximum emission levels allowed under applicable emission limitations
and assumes worst case meteorological conditions based on evidence of
historical meteorological patterns. Models operate on assumptions, but
the assumptions are based on facts. The models analyze the combined
effects of the worst case values of the two variables (emission levels
and meteorology) on ambient concentrations of pollutants at a multitude
of ``receptors'' or sites, to predict maximum concentrations that may
not have occurred yet, but could occur in the future.
In general, appendix W and the Guideline models have been adopted
by rulemaking in accordance with the Administrative Procedures Act.
They may not be challenged in this action; they could have been
challenged only by timely petition to the U.S. Court of Appeals for the
D.C. Circuit in accordance with section 307(b) of the Act.
(c) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment # 1; Goetz letter, document # IV.A-18, exhibit D, comment #
III, p. 43) stated that we ignored contradictory information from the
monitors in favor of modeling when we issued the 1993 letter, thus
invalidating the SIP Call.
Response: Historically, the seven monitors in the Billings/Laurel
area (the State added a new monitor in 1999) have not measured
violations of the SO2 standards. We were aware of the non-supportive
monitoring information at the time of the 1993 letter and discussed the
data in our letter (see document # II.G-1). There we cited cases that
approve EPA's reliance on modeling results in the face of apparently
contrary monitoring data. In Northern Plains Resource Council v. U.S.
Environmental Protection Agency, 645 F. 2d 1349 (9th Cir. 1981), for
example, the court held that EPA's reliance on a model would be
arbitrary and capricious only if ``EPA ignored reliable data that so
undermined EPA model projections that reliance on the model was
irrational.'' See 645 F.2d at 1362.
In the SIP Call, we are not ignoring reliable data. We analyzed the
available monitoring data, compared it with modeling results, and
determined that it did not undermine the modeling results because the
data had not been obtained at locations where the models predicted
maximum concentrations of SO2. In addition, real time monitoring data
was available to the operators of some of the industry sources, who
could have controlled their operations to avoid NAAQS exceedances when
concentrations approached critical levels. For these reasons, we
conclude that the lack of monitored violations do not undermine the
models' projections.
(d) Comment: Two commenters (MSCC letter, document # IV.A-20,
comment # 3.L; Goetz letter, document # IV.A-18, exhibit D, comment #
III.B, p. 45) stated that, after the 1993 letter, the State moved its
monitors to two of the locations where maximum concentrations were
predicted, but that these monitors still have not registered violations
of the SO2 NAAQS.
Response: The monitors' failure to register violations is not
surprising. Information provided by the sources and MDEQ indicates that
actual emissions have declined since 1993. Modeling can analyze the
combined effects of the highest allowable emission levels and worst-
case meteorological events at numerous receptors to predict violations.
Any one monitor is unlikely to measure such synchronous events at a
single location. When actual emission levels are lower than allowable
emissions and, as in the Billings/Laurel area, are actually declining,
monitored levels cannot be expected to match computer modeling results.
In Northern Plains Resource Council, the Ninth Circuit observed
that monitored data can only be used to validate (or, by implication,
invalidate) a model, if the data are collected under the same
conditions for which the model is predicting ambient concentrations.
See 645 F.2d at 1364. For the Billings/Laurel SIP Call, the model
predicted violations at allowable levels, the maximum levels of
emissions permitted under the existing SIP. It is unlikely that the
sources in the area were emitting SO2 at maximum allowable levels at
the same time, during the most adverse meteorological conditions.
Furthermore, even now, monitors are not located at many locations where
the SIP Call modeling indicated NAAQS violations. Therefore, the
monitoring data were not collected under the same conditions for which
the models were predicting violations. Although these conditions may
not have occurred yet, they can occur in the future. The SIP Call is
necessary to protect the air quality in the Billings/Laurel area now
and in the future.
The same point was made in another case, PPG Industries, Inc. v.
Costle, 630 F.2d 462 (6th Cir. 1980). There the court agreed with EPA
that ``projected future violations may provide the basis for a
nonattainment designation in currently clean areas.'' 630 F.2d at 464.
Contrary monitoring data would not necessarily bar a nonattainment
designation (or a SIP Call) based on modeling to protect the NAAQS in
the future. The court held that ``EPA need only offer record support of
the accuracy of the model used.'' Id. at 467. Record support for the
model used for the Billings/Laurel SIP Call is provided by the EPA
Guideline, appendix W.
The PPG Industries court observed that if EPA based its action on
predictions of future violations, ``monitored data which merely show
historical attainment of air quality standards'' do not undermine the
agency's decision. Id. at 468. The monitored data being offered to
contradict modeling results must show that the modeled predictions are
``unsupportable.'' Id. The commenters have not shown that the modeled
predictions of violations in Billings/Laurel are unsupportable in
comparison to monitoring data, for the reasons already cited--the lack
of monitoring
[[Page 22187]]
data from locations of predicted maximum concentrations, the lack of
monitoring data for impacts of maximum allowable emissions, the
possibility that source operators changed operations when feedback from
monitors indicated concentrations of SO2 approaching the critical
values, and the possibility that sources were emitting at reduced
levels when the most adverse meteorological conditions occurred.
3. Usefulness of More Refined Models
(a) Comment: Two commenters (MSCC letter, document # IV.A-20,
comment #'s 3.T, 3.U, and 8C; Goetz letter, document # IV.A-18, exhibit
D, comment #'s III.D.3, pp. 50-51) stated that a more refined computer
model should have been used to develop the revised SIP for the
Billings/Laurel area. They commented that the CTDMPLUS model, in
particular, is more accurate and predicts lower concentrations in areas
of complex terrain than COMPLEX I. These commenters pointed out that
CTDMPLUS was used instead of COMPLEX I to develop the SO2 SIP for East
Helena, Montana.
Response: The Billings/Laurel area differs in several respects from
the East Helena area. East Helena has only one significant source of
SO2, the Asarco lead smelter. The smelter has three tall stacks that
emit most of the source's SO2. In the Billings/Laurel area, there are
seven industrial sources with a combined total of several dozen
different stacks that must be modeled. CTDMPLUS is limited in its
ability to consider the impacts of more than a few emission points at
the same time. The complexity involved in applying CTDMPLUS to develop
emission limitations and show attainment for so many different emission
points would make the modeling analysis infeasible in the Billings/
Laurel area. The complexity of the analysis would also preclude the use
of variable emission limitations, which are now in place at some of the
Billings/Laurel sources.
In addition, it is not possible to accurately apply CTDMPLUS
without a scientifically rigorous set of local meteorological data.
Such data were available for East Helena, but not for the Billings/
Laurel area. In East Helena, Asarco collected the appropriate on-site
meteorological data for use in CTDM-PLUS modeling, including upper air
measurements that were representative of conditions at plume height.
The meteorological monitoring program was submitted to EPA and MDEQ in
August 1992 for approval, and data collection began in May 1993. There
are no similar data available in the Billings area for application of
CTDMPLUS.
(b) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment # 54; MSCC letter, document # IV.A-20, document # 3V; Goetz
letter, document # IV.A-18, exhibit D, comment #'s III.D.3, p. 51;
III.H, p.59) stated that MSCC proposed to gather the necessary
meteorological data for the Billings/Laurel area. These commenters
asserted that MDEQ's and EPA's failure to approve the proposal resulted
in an arbitrary and capricious reliance on an outdated and over-
predictive screening model (COMPLEX I).
Response: MSCC submitted a meteorological monitoring proposal in
1996, nearly three years after the modeling protocol for Billings/
Laurel was developed and applied. Within a month of receiving MSCC's
meteorological monitoring proposal from MDEQ, we reviewed it and
responded that the proposal raised serious problems that could
potentially invalidate any data collected. See letter from Kevin
Golden, EPA, to John Coefield, MDEQ, September 26, 1996 (document #
IV.C-28). To our knowledge, the company did not revise and re-submit
its proposal.
(c) Comment: Two commenters (MSCC letter, document # IV.A-20,
comment # 3.U; Goetz letter, document # IV.A-18, exhibit D, comment #
III.D.1 and 2, p. 48) stated that MSCC's consultant, Michael Machler,
applied CTDMPLUS in modeling tests at a site in Billings called
Sacrifice Cliffs, located in elevated terrain. The results were 50-60
percent lower than those predicted by COMPLEX I and were in close
agreement with monitoring data at the site, which indicated levels one-
half to one-third the concentrations predicted by COMPLEX I.
Response: One of the commenters (Goetz letter, document # IV.A-18,
exhibit D, comment # III.D.3) admitted that meteorological data from
East Helena were used for these modeling tests, because the specific
data inputs needed for the model were not available for Billings. For
CTDMPLUS, unlike ISC2/COMPLEX I, predictions may be very sensitive to
changes in upper air meteorological conditions, such as plume altitude,
wind, and turbulence. These conditions must be measured locally to
generate appropriate data inputs for the model. Using critical
meteorological data from another site would invalidate any testing with
CTDMPLUS. In addition, a single monitor is insufficient to test any
model. In areas such as Billings, where SO2 concentration gradients are
high (i.e., a significant change in concentrations between receptor
points), a dense monitoring network is necessary to adequately test a
model.\16\
---------------------------------------------------------------------------
\16\ ``Interim Procedures for Evaluating Air Quality Models
(Revised),'' EPA-450/4-84-023, September 1984, page 48 (document #
IV.C-78).
---------------------------------------------------------------------------
(d) Comment: One commenter (Conoco letter, document # IV.A-24, p.3)
suggested that if we believe the SIP needs to be modeled again to
address the modeling concerns EPA raised in the proposed rulemaking, we
should consider using the CALPUFF model for future modeling. The
commenter noted that CALPUFF was used in a study in West Virginia and
Ohio to establish SO2 controls within the study area. Another commenter
(Goetz, document # IV.A-18, exhibit D, comment # III.D.2) stated that
MSCC's consultant, Michael Machler suggested that CALPUFF could be used
in the Billings/Laurel area.
Response: We do not agree that CALPUFF should be used in the
Billings/Laurel area. CALPUFF is a refined model that has been applied
in complex terrain, but is not listed in the Guideline on Air Quality
Models as a preferred model. It is not appropriate for regulatory
applications, without further study. A similar model, MESOPUFF, is
listed in appendix W for evaluating long-range transport issues (i.e.,
distances greater than 50 kilometers from the source). This model would
not be considered appropriate, however, for evaluating near-source
impacts, such as those evident in the Billings/Laurel area. Ohio and
West Virginia used CALPUFF in a non-guideline application, following
the protocol for an on-site modeling evaluation study provided in
appendix W, section 3.2 (``Use of Alternative Models''). Alternative
models are used on a case-by-case basis, when the EPA Regional Office
believes such use is justified. We do not believe that application of
CALPUFF is appropriate for the Billings/Laurel area at this time
because its applicability has not been established (or even proposed).
(e) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.D.2, p. 49) indicated that Michael Machler, a
consultant for MSCC, suggested that another model, AERMOD, be used in
complex terrain.
Response: AERMOD is a new model that was not available when the SIP
modeling protocol was developed in 1993. It has been discussed as a
possible future replacement for ISC in the modeling Guideline. At this
time, it has not been proposed for public review and comment. Reviewing
all the facts, we conclude that MDEQ used the best
[[Page 22188]]
available models to perform computer modeling for the Billings/Laurel
SIP.
(f) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.D, p. 47) stated that the modeling receptor on
Sacrifice Cliffs is the most controlling and ``drives the entire SIP,''
implying that modeling for complex terrain is the most critical element
of the attainment demonstration and that a refined model should have
been used for complex terrain. The commenter also stated that the most
controlling receptors for MSCC, ExxonMobil and YELP are not on
Sacrifice Cliffs, but in the hills to the south.
Response: There are in fact a number of different receptor sites
where predicted concentrations of SO2 in the pre-SIP revision scenarios
exceeded the SO2 NAAQS, both in complex terrain and in simple terrain.
There is not one receptor site that is most controlling for the SIP.
Many of the sources in the current SIP attainment demonstration have
emission limitations based on predictions from ISC2, the refined EPA
Guideline model. Other sources are controlled based on the approved
screening model, COMPLEX I.
It is not clear what the commenter means by ``controlling
receptors'' for various sources. As one might expect, the maximum
incremental contributions from each source generally were predicted to
occur close to that individual source. If a receptor location close to
a specific source is predicted to exceed the NAAQS, the State would
have the option of controlling emissions from the nearby source, or
reducing emissions from the ``background sources.'' Given the large
number of facilities and emission points in the Billings/Laurel area,
emission reductions were needed from a number of sources to show NAAQS
attainment at all receptors.
(g) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment #'s III.D.3, p.50; III.H, p. 59) stated that using
the less refined, less accurate COMPLEX I model for complex terrain for
the SIP Call and SIP modeling is entirely arbitrary and capricious.
Response: COMPLEX I is a Guideline screening model, and its
application is appropriate under our regulations as long as it is
applied as directed by appendix W. COMPLEX I results may be used for
all regulatory purposes unless a refined model is available, which was
not the case for the Billings/Laurel area. If any approved model were
to over-predict ambient concentrations and call for more restrictive
emission limitations than a hypothetical, more refined model, the
modeled attainment demonstration would not be invalid. Courts have
accepted that a certain level of over-prediction is allowed by the Act.
In Cleveland Electric Illuminating Co. v. EPA, 572 F.2d 1150 (6th Cir.
1978) cert. den. 439 U.S. 910, 99 S.Ct. 278 (1978), for example, the
Sixth Circuit approved EPA's reliance on an earlier computer model
(RAM) for setting SO2 limitations in a federal implementation plan,
even though an industry study showed that the RAM model over-predicted
violations and was contradicted by data from ambient monitoring.
The court observed:
SO2 emissions have a direct impact upon the health and the lives
of the population of Ohio--particularly its young people, its sick
people, and its old people. If the RAM model did over-predict
emission rates, such a conservative approach was apparently
contemplated by Congress in requiring that EPA plans contain
``emission limitations * * * necessary to insure attainment and
maintenance'' of national ambient air standards. 572 F.2d at 1164
(emphasis in original) (citing former 42 U.S.C. section 1857c-
5(a)(2)(B), now revised and recodified at 42 U.S.C. 7410(a)(2)).
4. Inputs Used in Computer Models
(a) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.G, pp. 57-58) stated that the use of non-local
meteorological data ``exacerbates the arbitrariness'' of the computer
modeling; the commenter objected to the use of data from Great Falls,
Montana and from the Billings airport. Another commenter (MSCC letter,
document # IV.A-20, comment # 8.D) also criticized us for using non-
local data in the models.
Response: The computer modeling was not rendered unreliable by the
use of non-local meteorological data. The modeling protocol that was
used for the SIP revision was developed by the State in early 1993 and
approved by us in August 1993. The protocol development process
included substantial input and comments from the public, including
industry groups and their constituents. No meteorological towers or
vertical temperature soundings were available in the Billings/Laurel
area to provide on-site data for upper air conditions, one component of
the meteorological data needed for computer modeling. Instead, MDEQ
used representative data from Great Falls, which, although 180 miles
from Billings/Laurel, is similarly located on the high plains to the
east of the Rocky Mountains. Thus MDEQ made use of available data for
upper air conditions that were most representative of the conditions in
the Billings/Laurel area. This approach is approved by us. See 40 CFR
part 51, appendix W, section 9.3.
MDEQ used temperature sounding data from Great Falls in the ISC2/
COMPLEX I model to determine mixing height. For point source emissions
with significant plume rise, such as the emissions from the Billings/
Laurel sources, predicted concentrations from ISC2/COMPLEX I are
relatively insensitive to changes in mixing height, and use of non-
local meteorological data for this purpose would not make a significant
difference. CTDMPLUS, by contrast, requires considerably more detailed
upper air input information than ISC2. CTDMPLUS predictions may be very
sensitive to changes in several conditions that can only be measured
with a meteorological tower, such as plume altitude, wind, and
turbulence. As we discussed in section V.D.3.a, above, specialized
local meteorological data, which were unavailable for the Billings/
Laurel area, would be needed to apply this model accurately.
(b) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # III.G) stated that MDEQ improperly used data from
the Billings airport to represent meteorological conditions in the
lower atmosphere, that this location is not representative, because it
is miles from both the sources and the critical receptors, and that
data from the ambient monitors should have been used.
Response: We agree with MDEQ that the Billings airport data are
representative of the area. Meteorological data from the ambient
monitors at Lockwood Park, Brickyard Lane, Coburn Road and Laurel were
not used because these monitors, located in the Yellowstone River
Valley, are subject to variable ground-level conditions and are not
representative of conditions affecting plume-height emissions as they
are transported over the valley. The most representative data available
were those obtained at the airport, which is located on a bluff above
the valley, not subject to localized meteorological effects that occur
along the valley floor.
(c) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 1; MSCC letter, document # IV.A-20, comment #'s 3M, 3O)
stated that the SIP Call is flawed because the modeling used factually
inaccurate assumptions for emission rates, stack parameters, and other
factors.
Response: The SIP Call modeling used data inputs from an earlier
emissions inventory that did contain some errors. These errors were
corrected, and the corrected inputs were used in the modeling for SIP
development. The SIP
[[Page 22189]]
Call modeling showed NAAQS violations at many sites at allowable
emission levels. With corrected inputs, the modeling continued to
predict NAAQS violations as much as two times over the national
standard, thus supporting the SIP Call.
(d) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 108) stated that CEMS data now indicate an error in the
assumed buoyancy flux for MSCC's main stack; the current modeling
protocol contains an assumption which significantly underestimates the
average rise in emissions. Any revised modeling should correct this
assumption.
Response: We agree that future modeling should include all
corrected data. In any modeling analysis, input data are based on the
best available information at the time of the analysis. CEMS
measurements of flow and temperature data provide the best estimates of
stack parameters, and values based on CEMS data should be used in any
future SIP modeling for Billings provided the CEMS data are accurate.
Other data inputs have been corrected and added, as we discussed in the
TSD for this rulemaking (document # III.B-1). Any future modeling in
the Billings/Laurel area should incorporate all corrections. The SIP
limitations are based on the best information available at the time the
attainment demonstration was modeled, and the same will be true for any
FIP limitations that are developed.
(e) Comment: MSCC's consultant, Michael Machler, stated that he had
identified problems in the past with the way mixing heights are
calculated in dispersion modeling. He stated that EPA has apparently
corrected the problem and that ISC3, the newer version of the ISC2
model used for the Billings/Laurel SIP, now provides for more accurate
calculations of mixing height. The modeling for the SIP used the older
version, however, and has not been updated with respect to calculation
of mixing heights. See Goetz letter, document # IV.A-18, exhibit E,
page 1.
Response: In 1994, when the State performed the modeling for the
attainment demonstration, MDEQ used the most accurate information and
the best data base available at the time. ISC2 was then the preferred
Guideline model. The newer ISC3 is comparatively more refined, but the
correction in calculation of mixing heights would not make a
significant difference in this case, because the Billings SIP modeling
predictions (ISC2 and COMPLEXI) are relatively insensitive to changes
in mixing height. We would not expect to see any significant changes in
predicted concentrations with the newer version of the model. In
addition, dispersion models and data bases are continually being
improved. The task of demonstrating attainment could never be completed
if we or the State were compelled to update the analysis with each new
refinement. For the FIP, we intend to continue to use ISC2 as the
applicable model to fill in the gaps in the State's attainment
demonstration created by our disapproval of the emission limitations
for MSCC's 100-meter stack. Some source parameters have been corrected
since the 1994 modeling analysis (see Response V.D.4.(d), above), but
we intend to use the same meteorological data and modeling protocols
the State used, so that the results will be comparable.
5. Two Modeling Demonstrations
(a) Comment: One commenter (State letter, document # IV.A-23)
stated that we did not acknowledge that Montana submitted two separate
attainment demonstrations for SO2--one for the Billings area and one
for the Laurel area. The commenter indicated that the Laurel area was
modeled assuming the SIP prescribed emission limitations for Cenex and
the pre-SIP potential emissions for the Billings sources. Therefore,
the Laurel SIP demonstrates compliance with the NAAQS regardless of
whether a revised SIP is approved and implemented in Billings. The
Billings area was modeled assuming all sources in the Laurel and
Billings areas are at SIP prescribed emission rates. Therefore, the
Billings SIP depends upon approval of the Laurel SIP to demonstrate
attainment. The commenter is requesting that we acknowledge the two
attainment demonstrations in our final action and treat the two
separately in that action.
Response: We agree with the commenter and acknowledge that there
are two attainment demonstrations--one for the Billings area and one
for the Laurel area. However, since the flare issue applies to sources
in both Billings and in Laurel, we still believe the attainment
demonstration for both areas should be disapproved for lack of
enforceable flare emissions at the applicable sources. See flare
discussion in section C, above.
E. EPA'S Partial Approval
In our July 28, 1999 action (64 FR 40791), we proposed to partially
approve, conditionally approve and partially disapprove the Billings/
Laurel SO2 SIP.
Summary of Comments and Response
Two commenters objected because we did not fully approve the SIP.
Among other things, the commenters stated that our proposed action
intruded on State responsibility; raised Tenth Amendment concerns; and
may violate the U.S. Constitution. One commenter submitted concerns
regarding the conditional approval.
We have considered the comments received and still believe our
proposal to partially approve and partially disapprove\17\ the
Billings/Laurel SO2 SIP was a correct action.
---------------------------------------------------------------------------
\17\ We had also proposed to conditionally approve the SIP. On
May 4, 2000 the Governor of Montana submitted a SIP revision to
fulfill the commitments on which the proposed conditional approval
was based. Since the Governor has fulfilled has commitment, we
believe it is not appropriate to finalize the conditional approval.
Instead, we will complete notice-and-comment rulemaking on those
portions of the July 29, 1998 submittal we proposed to conditionally
approve on July 28, 1999 and all of the May 4, 2000 submittal.
---------------------------------------------------------------------------
The following is a summary of the comments received and our
response to the comments.
1. Intrusion Into State Regulatory Decision
(a) Comment: More than one commenter (Goetz letter, document #IV.A-
18, exhibit D, pp.61-63; MSCC letter, document #IV.A-19, comment #16;
MSCC letter, document #IV.A-20, comment #1.C) argued that EPA's
proposed action intrudes on the primary responsibility of State and
local governments to implement the Clean Air Act. In the view of one of
the commenters (Goetz), it is the State's role to balance the interests
of the seven emitting sources in the Billings/Laurel area, and EPA has
no authority to disturb the balance the State has struck. The commenter
claimed that EPA may not approve the emission limits for some of the
sources while disapproving MSCC's emission limits. According to the
commenter, if EPA is going to disapprove MSCC's limits, the whole SIP
should be remanded to the State to allow the State to re-evaluate the
entire mix of emission limits in the area. The commenter cited case law
to support these comments, including case law that suggests that EPA
may not interfere with the State's choices of emission limitations as
long as the NAAQS are met. The commenter also cited case law from the
7th Circuit that suggests that EPA may not render a SIP more stringent
through partial approval. In the commenter's view, EPA's proposed
actions trigger serious Tenth Amendment concerns.
Response: We agree that the Act grants the States the primary
[[Page 22190]]
responsibility to select emissions limitations for sources. However,
the Act also reserves to us a fundamental responsibility to ensure that
SIPs meet the requirements of the Act. See, e.g., Union Electric
Company v. EPA, 96 S.Ct. 2518 (1976); sections 110(a)(2)(A), 110(k),
and 110(l) of the Act. In the instant case, our responsibility is
broader than the commenter portrays it--yes, we must ensure that the
SIP shows attainment of the NAAQS, but we must also ensure that the SIP
meets the requirements of section 123 of the Act and our stack height
regulations in showing attainment. Congress understood that emissions
controls and dispersion through tall stacks were two different means to
attainment of the NAAQS. Congress chose to restrict the use of
dispersion techniques to meet the NAAQS and directed us to adopt
regulations to carry out this restriction. In this case, one reason we
cannot fully approve the Billings/Laurel SIP is that MSCC's emission
limits are based on stack height credit that is inconsistent with our
stack height regulations.
Another reason we cannot fully approve the SIP is that the State's
submission lacks enforceable emission limitations on flares. Without
enforceable limitations on these sources of SO2 emissions, the SIP
fails to satisfy the requirement of section 110(a)(2)(A) of the Act
that each plan include ``enforceable emission limitations . . . as may
be necessary or appropriate to meet the applicable requirements of this
chapter.'' MDEQ established a State-only limitation on flare emissions.
Modeling demonstrates that the limitation is necessary to protect the
NAAQS. Unless an equivalent limitation is included in the federally
enforceable SIP, the implementation plan for the Billings/Laurel area
will be deficient, because it does not fully meet the planning
requirements of section 110 of the Act nor adequately protect air
quality in the area. For this reason as well, we are disapproving the
attainment demonstration.
We do not believe that our action to disapprove the attainment
demonstration and MSCC's emission limits is inconsistent with the cases
the commenter has cited. Once we have determined that a portion of a
SIP is inadequate, section 110(k)(3) of the Act grants us the authority
to partially approve parts of a SIP that are consistent with the Act's
requirements, while disapproving parts that are inconsistent with the
Act's requirements. That is what we are doing here--we are disapproving
MSCC's emission limits because they are inconsistent with the
requirements of the Act and our regulations. We are not obligated to
uphold a State's balancing of emission limits among relevant sources
where the State's emission limits for one of the sources do not meet
the requirements of the Act. We have no authority to ``remand'' a SIP
to a State, as the commenter suggests. Instead, we have approval and
disapproval authorities provided by the Act, and once we disapprove all
or part of a required SIP, we have an obligation to issue a FIP
pursuant to section 110(c) of the Act.
It is only through a FIP that we would determine substitute
emission limits for MSCC, as the 7th Circuit case cited by the
commenter clearly states. Thus, as discussed further in section
V.E.1.d, below, our disapproval of MSCC's emission limits does not
render the SIP more stringent than the State intended.
We do not believe our partial disapproval triggers Tenth Amendment
concerns. States are not coerced by the provisions of the Act directing
them to adopt SIPs; the federal government may bear the regulatory
burden in whole or in part, instead. See, Commonwealth of Virginia v.
Browner, 80 F.3d 869, 882 (4th Cir. 1996). The State remains free to
revise the SIP emission limits for MSCC and for other sources as well,
but before we will approve such a revision, the revision must meet the
requirements of the Act and our regulations, including stack height
requirements. This issue is further discussed in section V.E.2, below.
(b) Comment: One commenter stated that the court in Commonwealth of
Virginia v. Environmental Protection Agency (108 F.3d 1397 (D.C.Cir.
1997)) held that Section 110 of the Act did not confer upon EPA the
authority to condition our approval of the plan of any state on the
state's adoption of a specific control measure, and that we could not
condition approval of the Billings/Laurel SO2 SIP on a particular
emission limitation for MSCC's 100-meter stack. See Goetz letter,
document #IV.A-18, exhibit D, comment #V, p. 63.
Response: We agree with the commenter that this is a correct
statement of the holding in Commonwealth of Virginia. However, in this
case we are not conditioning approval of the Billings/Laurel SO2 SIP on
the State's adoption of a specific control measure. We are disapproving
an emission limitation (i.e., 100-meter stack emission limitation)
because it violates the prohibition of section 123 of the Act on giving
credit for stack heights in excess of good engineering practice.\18\
The State nevertheless remains free to devise specific emission
limitations for the sources, provided it can demonstrate that the
selected limits will insure attainment of the NAAQS and the limits meet
the requirements of section 110(a)(2) of the Act.
---------------------------------------------------------------------------
\18\ We are also disapproving the escape clause in all the
stipulations, MSCC auxiliary vent stack emission limit, the
attainment demonstration (because of the stack height issue, flare
issue and auxiliary vent stack issue), the provisions that allow
sour water stripper emissions to be burned in the flare at Cenex and
ExxonMobil, and the plan for failing to meet RACM/RACT.
---------------------------------------------------------------------------
The commenter cited an earlier Supreme Court opinion (Train v.
Natural Resources Defense Council, 421 U.S. 60 (1975)) to support his
position that we lack authority to disapprove the emission limitation
for MSCC's 100-foot stack. That opinion, quoted in Commonwealth of
Virginia, held that EPA does not have authority to disapprove a State's
choice of emission limitations if they are part of a plan which, as a
whole, satisfies the requirements of section 110(a)(2) of the Act.
According to the Train court, EPA may disapprove a State's plan and
promulgate a FIP only if the State's plan does not protect the NAAQS.
Otherwise, ``the State is at liberty to adopt whatever mix of emission
limitations it deems best suited to its particular situation.''
Commonwealth of Virginia, 108 F.3d at 1407-1408, quoting Train, 421
U.S. at 79.
We do not agree that Train creates a bar to our disapproval of an
emission limitation that does not comply with section 123 of the Act.
That case was decided in 1975, before the 1977 amendments to the Clean
Air Act added section 123 with its prohibition against allowing credit
for excessive stack height. Train was also decided before the 1990
amendments added section 110(k), which contains specific criteria for
EPA action on SIPs, including the condition that each SIP or SIP
revision must ``meet all the applicable requirements'' of the Act.
Train, therefore, does not preclude us from disapproving state emission
limitations that conflict with specific provisions of the Act and EPA's
implementing regulations. See also section 110(l) of the Act.
Commonwealth of Virginia, too, was not concerned with stack
heights; that case concerned an EPA regulation imposing California's
automobile emission standards on the states in the Northeast Ozone
Transport Region. The court undertook a statutory analysis of
complicated interactions among four different sections of the Act
(sections 110, 177, 184, and 202) before concluding that section 110
did not give EPA the authority to prescribe specific
[[Page 22191]]
SIP limitations in that case.\19\ In Commonwealth of Virginia, we were
not simply disapproving a state implementation plan; we were directing
states to adopt particular emission limitations. In this case, we are
disapproving particular limitations in Montana's plan; we are not
prescribing a particular limitation. The State retains the authority to
adopt any emission limitation or mix of limitations it chooses as part
of the Billings/Laurel SO2 SIP, as long as the measures comply with all
applicable provisions of the Act, including section 123, and EPA's
regulations implementing the Act. We believe that neither Train nor
Commonwealth of Virginia precludes our action here, which is authorized
by section 123 and section 110(k) of the Act.
---------------------------------------------------------------------------
\19\ To the extent that Commonwealth of Virginia may be read as
holding that section 110(k)(3) conditions EPA's approval of a SIP
revision on meeting section 110(a)(2) criteria only and not on
meeting other requirements of the Act (see 108 F.3d at 1409), such
an interpretation is incorrect. Section 110(k)(3) states, ``[the
Administrator shall approve such submittal as a whole if it meets
all of the requirements of this chapter.'' The phase ``this
chapter'' means the entire Act, which comprises Chapter 85 (``Air
Pollution Prevention and Control'') of Title 42 of the U.S. Code
(``Public Health and Welfare''). Section 110 of the Act is one
section of Subchapter I (``Programs and Activities'') of Chapter 85.
By the plain words of section 110(k)(3), EPA may approve a SIP or
SIP revision only if it meets all the applicable requirements of
Chapter 85 and thus all requirements of the Act. See also section
110(l) of the Act.
---------------------------------------------------------------------------
(c) Comment: One commenter stated that the whole SIP should be
remanded to allow the State to re-evaluate the entire mix of
limitations, so fairness can be preserved. See Goetz letter, document
#IV.A-18, exhibit D, comment #V, p. 62.
Response: We informed the State as early as July 1996 (see document
#II.C-5) that the stack height credit which MDEQ proposed to allow for
MSCC's 100-meter stack did not comply with our stack height
regulations. The State could have acted at any time before adopting and
submitting the SIP revision in July 1998 to limit the stack height
credit for MSCC and re-evaluate some or all of the SO2 emission
limitations in light of the more limited credit. Since the State did
not take that action, we are now disapproving the stack height credit
and emission limitations for the 100-meter stack at MSCC. We plan to
propose a FIP to fill in the gap with an appropriate emission
limitation that both demonstrates attainment and complies with our
stack height requirements. The promulgation of a FIP, however, will not
relieve the State of its primary responsibility to adopt a fully
satisfactory SIP; the State continues to have the authority and
responsibility to re-evaluate the appropriateness of emission
limitations for the Billings/Laurel area and to submit a SIP revision
that will satisfy all statutory requirements, including the section 123
prohibition against credit for stack height in excess of good
engineering practice.
(d) Comment: One commenter (Goetz letter, document #IV.A-18,
exhibit D, comment #V., p. 63) stated that our partial disapproval
makes the SIP more stringent than the State intended, an effect
prohibited under the Act.
Response: The holdings in Bethlehem Steel Corp. v. Gorsuch, 742
F.2d 1028 (7th Cir. 1984), cannot be considered binding outside the
Seventh Circuit. Assuming for purposes of responding to the comment
that Bethlehem Steel governs our action on Montana's SIP, in this case,
the SIP is not more stringent than the State intended. In contrast to
the situation in Bethlehem Steel, we are not disapproving a part of a
SIP regulation that contains an exemption from an emission limitation
that we are approving in another part of the same regulation. In
Bethlehem Steel, the court held that we could not use our partial
approval/partial disapproval authority in this way to delete a limiting
condition on a state requirement and make the portion of the
requirement remaining in the federally approved SIP more stringent than
the original regulation adopted by the state. See 742 F.2d at 1036. The
court acknowledged that we have the authority to set more stringent
limitations, as necessary to protect the NAAQS, but held that we must
do so through adopting a Federal Implementation Plan (``FIP''); we
cannot avoid the extra procedural process of adopting a FIP by simply
disapproving the SIP in part. See id. at 1035.
Our disapproval of the stack height credit extended by the State to
MSCC does not make the federally approved SIP more stringent than the
State stipulation, and we are not attempting to avoid promulgating a
FIP. Partial disapproval here does not give us the power to enforce an
emission limitation from which the source would be exempt under state
law. The same is true for our disapproval of the attainment
demonstration for lack of flare emission limitations. The effect of our
partial disapproval is just the opposite: the emission limitations
established by the State for MSCC's 100-meter stack and for the flares
are state-enforceable, but not federally enforceable. To establish a
more stringent, federally enforceable limitation for MSCC or the
flares, we must promulgate a FIP. This is exactly what we intend to do,
to fill all the regulatory gaps created by our partial disapproval of
the SIP. This is the remedy approved by the Seventh Circuit when a
State's SIP is inadequate or otherwise fails to meet Act requirements.
(e) Comment: One commenter (MSCC letter, document #IV.A-19, p. 5
and comment #60) stated that EPA has not identified emission limits it
proposes to impose on MSCC. According to the commenter, this silence
makes it infeasible for MSCC or the State to determine the effects of
EPA's proposals on MSCC. This commenter said that the correct approach
before EPA takes final action is for EPA to identify and explain its
alternative so all parties may intelligently comment on them.
Response: The purpose of our action here is not to establish
emission limits for MSCC. The purpose is to determine whether the
State's SIP submittal meets the requirements of the CAA and our
regulations. We think we have adequately described why aspects of the
SIP do not meet CAA requirements and why partial disapproval is
warranted. As a legal matter, we cannot impose alternative emission
limits through a SIP disapproval, but, instead, can impose such limits
only through promulgating a FIP. Although we could have separately
proposed a FIP simultaneously with our disapproval of the SIP, we chose
not to and are not required to under the CAA. Our disapproval of the
SIP has no immediate impacts on MSCC or any other source. If and when
we promulgate a FIP for the area, we will first propose the FIP,
including emission limits for sources subject to the FIP, provide an
opportunity for the oral presentation of data, views, or arguments, and
take written comment from the public.
(f) Comment: One commenter (MSCC letter, document #IV.A-19, #60)
stated that EPA's FIP, which is yet to come, may be inconsistent with
the law or may be impractical for the State to impose.
Response: We believe we have adequately explained, in our proposed
disapproval, and in this final disapproval, our bases for rejecting
portions of the SIP. We believe comments regarding a future FIP are
irrelevant to this action; any such concerns may be raised if and when
we propose a FIP. Moreover, if and when EPA adopts a FIP, EPA and not
the State will ``impose'' its requirements.
2. Constitutional Question: Tenth Amendment
(a) Comment: Two commenters (Goetz letter, document #IV.A-18,
exhibit D, comment #2, p. 9; MSCC letter, document #IV.A-19, comment
#1, 3rd
[[Page 22192]]
page) stated that through the SIP Call process and our proposed action
on the SIP we exerted undue influence over Montana's SIP development
process.
Response: We did not exert undue influence or coerce the State into
taking action in response to the 1993 letter. Under the Clean Air Act,
states have the basic choice of whether or not to participate in the
federal regulatory scheme. See Commonwealth of Virginia v. Browner, 80
F.3d 869, 882 (4th Cir. 1996). States are sovereigns in their own right
and independently make regulatory decisions affecting industry within
their borders. Similarly, we independently exercise the authority
provided by Congress to endorse or reject those decisions, for example
by approving or disapproving a SIP. Although we may advise a state as
to what we may or may not approve under the Act, states retain
responsibility for their regulatory decisions. See, e.g. Air California
v. U.S. Dept of Transportation, 654 F.2d 616 (9th Cir. 1981) (the
danger of losing federal funding may have exerted strong pressure but
did not relieve a state governmental entity of responsibility for its
decision). In that case, the Ninth Circuit declared that ``concepts of
coercion and duress are inappropriate in characterizing dealings
between federal and state governments.'' 654 F.2d at 621. See also
Shell Oil Co. v. Train, 585 F.2d 408, 414 (9th Cir. 1978) (federal
advice to a state agency ``cannot be equated with any kind of
coercion''). We do not believe that the SIP Call or our response to
requests for assistance from MDEQ took the form of coercion, nor
compelled MDEQ to make particular choices in developing a control
strategy for the Billings/Laurel area.
(b) Comment: Two commenters (MSCC letter, document # IV.A-19,
comment # 12 and Goetz letter, document # IV.A-18, exhibit D, comment #
V, p. 63) stated that our partial disapproval violates the principle of
primacy set forth in the Act and triggers serious Tenth Amendment
concerns.
Response: We do not believe that our action on the Billings/Laurel
SIP raises Tenth Amendment concerns. Federal governmental action can be
viewed as coercing a particular state action in violation of the Tenth
Amendment to the Constitution only when the State has no choice but to
participate in the federal regulatory framework. See, Printz v. United
States, 117 S.Ct. 2365 (1997); New York v. United States, 505 U.S. 144,
112 S. Ct. 2408 (1992). Our authority under the Act to disapprove parts
of a SIP does not raise the same level of sovereignty concerns found in
those cases: partial disapproval does not compel a state legislature to
adopt a federal regulatory program, as in New York, or commandeer state
officials to execute a federal law, as in Printz.
Under the Tenth Amendment, federal law may be designed to induce
state action. See Commonwealth of Virginia v. Browner, 80 F.3d. 869,
881 (4th Cir. 1996) (citing FERC v. Mississippi, 456 U.S. 742, 766, 102
S.Ct. 2126, 2141 (1982)). Neither the Act nor EPA compels states to
adopt SIPs or particular SIP provisions. But we can induce or persuade
states to adopt SIPs and SIP revisions and to make these conform to
federal requirements if states wish to obtain EPA approval of their
SIPS. See Commonwealth of Virginia, 80 F.3d at 881, where, in the
context of an operating permit program under Title V of the Act, the
Fourth Circuit ruled that ``the CAA does not compel the states to
modify their standing rules; it merely induces them to do so.'' That
case flatly rejected the argument that the incentives contained in the
Act to encourage approvable state participation amount to coercion.
Since Montana remains free under the Act to choose to not participate
in the CAA regulatory scheme, our final action on the SIP Call and the
SIP cannot be viewed as compelling the State's action.
(c) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 1, 4th page, 2, and 3) stated that we used our sanctions
and funding powers to coerce the State to take positions that
conflicted with prior agreements with industry and otherwise infringed
on MSCC's rights.
Response: By threatening to impose sanctions, we did not coerce or
compel state action on the SIP Call; to the extent that the threat of
sanctions had any effect on SIP development, it only helped to induce
or persuade the State to respond. On some issues, we were unable to
persuade the State of the correctness of our position, hence our
partial disapproval. In Commonwealth of Virginia, the Fourth Circuit
held that although the sanctions provisions of the Clean Air Act
potentially burden the States, ``they amount to inducement rather than
`outright coercion.' '' 80 F.3d at 881. The court declared that the
highway funding sanction is allowed by the Spending Clause (U.S. Const.
art. I, Sec. 8, cl. 1), allowing Congress to limit the award of federal
funds to provide for the ``general welfare,'' which, as defined by the
Commerce Clause (U.S. Const. art I, Sec. 8, cl. 3), ``gives Congress
the power to regulate `activities causing air or water pollution or
other environmental hazards that may have effects in more than one
State.' '' Id. (quoting Hodel v. Virginia Surface Mining & Reclamation
Ass'n. 452 U.S. 264, 282, 101 S.Ct. 2352, 2363 (1981)). The Fourth
Circuit held that the highway sanction does not rise to the level of
``outright coercion,'' because it does not deny all highway funding in
a state, only in non-attainment areas and only for projects that do not
promote safety or reduce air pollution. Id. The highway sanction,
therefore, ``is a valid exercise of the Spending Power. As a valid
exercise of that power, it also comports with the requirements of the
Tenth Amendment.'' 80 F.3d at 882.
The Commonwealth of Virginia court also held that the offset
sanction, which limits new construction or modification of major
stationary sources of air pollution in non-attainment areas, is
constitutional because it regulates private pollution sources, not
states as governmental entities. Id. The offset sanction, therefore,
does not violate ``the principles of federalism embodied in the Tenth
Amendment.'' Id., citing New York v. United States, 505 U.S. at 174,
112 S.Ct. at 2427; and Hodel, 452 U.S. at 288, 101 S.Ct. at 2366.
The final sanction we can use to induce the State to develop an
adequate SIP is to develop a FIP for the area, in lieu of all or part
of the state plan. This sanction, too, does not raise Tenth Amendment
concerns. Under the Commerce Clause, Congress may preempt state law
completely, or it may take the less drastic step of allowing the states
to avoid preemption by adopting and implementing their own state plans,
as long as these are adequate to address congressional concerns. Hodel,
452 U.S. at 289, 101 S.Ct. at 2366; Commonwealth of Virginia, 80 F.3d
at 883. Although section 110 of the Act provides that each State
``shall, after reasonable notice and public hearing, adopt and submit''
a SIP, this language does not impose a mandatory duty on the States,
but ``merely gives the States the first opportunity to adopt and submit
a plan.'' Sierra Club v. Indiana-Kentucky Electric Corp., 716 F.2d
1145, 1148 (7th Cir. 1983). A State may not be compelled to develop or
submit a SIP. District of Columbia v. Train, 521 F.2d 971, 984 (D.C.
Cir. 1975) (vacated on other grounds, 431 U.S. 99, 97 S.Ct. 1635
(1977)). If an adequate plan is not submitted, however, EPA may
establish a plan for the State. Id. Because the State is not commanded
to regulate, Montana could choose not to develop a SIP and instead let
us promulgate and enforce a FIP for the Billings/Laurel area. In that
case, the full regulatory burden would be borne by the federal
government, and the sanction is constitutional. See Hodel, 452 U.S. at
[[Page 22193]]
288, 101 S.Ct. at 2366; Commonwealth of Virginia, 80 F.3d at 882.
Montana could also choose, and has chosen, not to address all the
questions about the adequacy of the SIP that we raised in our proposed
rulemaking action, and let us promulgate a FIP to fill the gaps caused
by our partial disapproval. Neither partial disapproval nor
promulgation of a FIP, both of which are authorized by the Act,
violates the Tenth Amendment.
3. Constitutional Question: Delegation of Legislative Power
(a) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # VI, p. 64) stated that EPA's application of the
stack height rule to MSCC constitutes an unconstitutional delegation of
legislative power and cited a recent DC Circuit case, American Trucking
Ass'n, Inc. v. EPA, 175 F.3d 1027 (D.C. Cir. 1999). In the commenter's
opinion, EPA's stack height rule, as interpreted by EPA in this case,
is so loose and poorly drafted as to give the agency virtually
unfettered administrative discretion to make policy choices as it sees
fit. The commenter asserted that MSCC is faced with a situation in
which the State and EPA interpret the stack height regulations
differently.
Response: First, the D.C. Circuit has already upheld the stack
height regulations. They may not be challenged now based on the
commenter's theory. Second, we do not believe the non-delegation
doctrine is relevant to our interpretation or implementation of our own
regulations, which have already been determined to be valid. Our
application of our regulations is not a constitutional question.
Instead, the question is whether our interpretation and application of
our regulations in this case is consistent with the regulations or not.
As we have explained elsewhere, we believe that our interpretation of
the stack height regulations is reasonable.
We also note that the case relied on by the commenter has been
reversed by the United States Supreme Court. See Whitman v. American
Trucking Associations, Inc., et al., 531 U.S. 457, 121 S.Ct. 903, 149
L.Ed 2d 1, February 27, 2001.
Regarding the claim of differing State and EPA interpretations, it
is not unusual that we find it necessary, in the role Congress gave us
vis-a-vis SIPs, to disapprove part or all of a SIP submitted by a state
because we disagree with the state regarding the appropriate
interpretation of the Clean Air Act or our regulations. This does not
create a constitutional flaw in our action.
4. Constitutional Question: Taking of Private Property
(a) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 13) stated that our partial disapproval of the stack height
credit for MSCC's 100-meter stack and our consequent disapproval of the
emission limitations for that stack constitute a ``taking'' of private
property for public purposes, presumably under the Fifth Amendment of
the Constitution. The same commenter (MSCC letter, document # IV.A-19,
comment #'s 52 and 53) stated that our action transfers emission rights
from MSCC to other entities in future apportionment of the airshed, and
that we should pay MSCC just and reasonable compensation for eroding
the value of private property or creating ``involuntary servitude''
(sic).
Response: These comments are untimely. Our partial disapproval does
not have the effect of disturbing the stack height credit given by the
State or the state-enforceable emission limitation for this source. The
effect of our partial disapproval is to decline to make the emission
limitation for the 100-meter stack federally enforceable. Our
disapproval creates a gap in the federally enforceable SIP, which we
intend to fill by adopting a FIP. If we propose to adopt a FIP which,
in MSCC's belief, effects a regulatory taking of MSCC's property for
public purpose without just compensation, MSCC could raise the takings
issue at that time. It is premature to raise the issue now.
Even if the issue were ready to be addressed at this time,
regulation under the Act in general does not represent an
unconstitutional ``taking'' of private property under the Fifth
Amendment. See Sierra Club v. Environmental Protection Agency, 540 F.2d
1114, 1139-1140 (D.C. Cir. 1976) (``The use of private land certainly
is limited, but the limitation is not so extreme as to represent an
appropriation of the land''). See also South Terminal Corp. v.
Environmental Protection Agency, 504 F.2d 646, 678 (1st Cir. 1974)
(``The takings clause is ordinarily not offended by regulation of uses,
even though the regulation may severely or even drastically affect the
value of the land or real property''). In order to comply with the Act
and our regulations, a future SIP or FIP might have to impose a lower
emission limit on MSCC, but this would not amount to a taking, any more
than the imposition of other emission limits on MSCC would amount to a
taking.
(b) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # VII, pp. 65-66) stated that our disapproval of
parts of the ExxonMobil and MSCC stipulations relating to incorporation
of earlier stipulations and apportionment of the airshed is
unauthorized and may constitute an unconstitutional taking of MSCC's
property. The commenter further stated that the Act provides for
property rights in airsheds through its provision for emission trading
and that MSCC's tenure in the area creates rights in the airshed. These
are valuable property rights which may not be taken without just
compensation under the Fifth Amendment to the U.S. Constitution, the
commenter claimed. Another commenter (MSCC letters, document # IV.A-19,
comment #'s 50, 51, and 52; and document # IV.A-20, comment # 14)
stated that our position on ``property right'' defies the Constitution.
A scarce resource is being partitioned between competing users, as with
water rights. If the government takes property, it must make MSCC whole
through just compensation. Another commenter (ExxonMobil letter,
document # IV.A-28) stated that references to the earlier stipulations
should be deleted from the EPA-approved SIP. (The reader is referred to
further discussion of the incorporation of earlier stipulations in
section V.H., below.)
Response: The short answer is that our disapproval of the
particular language in the State stipulations does not affect any
rights enjoyed by MSCC, including any property rights in the
atmosphere, if they exist. Our disapproval affects only the federal
enforceability of provisions of the State stipulations. The provisions
themselves remain in effect as to their state enforceability. There has
been no taking of property that would raise Fifth Amendment concerns.
Even if our action were to affect MSCC's ``emission rights'' under
the SIP, these are not ``private property'' protected under the Takings
Clause of the Fifth Amendment. To the extent that MSCC has emission
rights, they are created by the enforceable emission limitations of the
SIP. It would be an exercise in circular reasoning to turn emission
rights created under a federal regulatory program into property rights
that cannot be altered by further regulation under the same program
without triggering constitutional protections against a governmental
taking. The emission rights created under the Act, whether part of a
SIP emissions trading program or the acid rain program or new source
review, are limited by and have value within the statutory program
only. They do not exist outside of the Act. We can alter the
[[Page 22194]]
emission limitations of a SIP that give rise to such emission rights,
thus changing their value, as long as our action has a proper
regulatory purpose such as protection of the NAAQS. Since we have not
yet proposed a FIP, a claim that we have improperly changed the value
of MSCC's emission rights is premature.
The argument that MSCC has established rights to emit merely by
having ``tenure'' in the Billings area is without foundation. Because
MSCC was constructed before 1977, it is true that at that time the
source was not subject to pre-construction permit requirements under
the Act and was ``grandfathered'' or exempted from prevention of
significant deterioration (``PSD'') requirements. However, since
passage of the Act in 1970, MSCC has been subject to potential
limitation of its emissions under the Act to protect the SO2 NAAQS.
This potential became an actual limitation in 1977, under the original
Billings/Laurel SIP, and again in 1996-98, under the SIP revisions that
have been adopted by the State. MSCC and the other sources in the area
do not enjoy any rights to emit pollutants that would cause or
contribute to a violation of the NAAQS, and currently permitted
allowable emissions levels do not constitute private property rights.
See, e.g., 40 CFR 70.6(a)(6)(iv): ``The permit does not convey any
property rights of any sort, or any exclusive privilege.''
(c) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # VII, p. 65) cited a Supreme Court opinion, Eastern
Enterprises v. Apfel, 524 U.S. 498, 118 S.Ct. 2131 (1998), to support
his contention that disapproval of the phrase ``apportionment of the
airshed'' in paragraph 1 of the MSCC stipulation effects a taking of
MSCC property.
Response: As already stated, partial disapproval of the SIP does
not affect any rights, including property rights, enjoyed by MSCC or
the other Billings/Laurel sources. In addition, neither the emission
rights existing under the SIP nor the State's apportionment of the
``airshed ''\20\ have the effect of creating property rights. See
response to the immediately preceding comment, Comment 4(b) above.
---------------------------------------------------------------------------
\20\ Actually, what is referred to as the ``airshed'' is the
difference between the ``background'' levels of SO2 without
contribution from any of the industrial sources and the NAAQS for
SO2; it is this difference which the State has apportioned among the
industrial sources in the Billings/Laurel area in its effort to
fairly burden each one. This difference in SO2 concentrations is not
a tangible thing capable of being possessed. Note that the
``background'' was both modeled and monitored. Monitored regional
background concentrations of SO2 were obtained from remote, rural
monitoring sites. These yielded a fairly pristine background. In the
modeled attainment demonstration, the background for any single
source consists of the regional background plus the background
contribution from any other sources upwind that are explicitly
included as inputs to the model.
---------------------------------------------------------------------------
Even if MSCC did hold an interest in ``private property'' created
by the ``apportionment of the airshed'' described in the stipulation,
the Eastern Enterprise opinion does not support MSCC's position that
such property has been taken. Eastern Enterprise concerns the effect of
the Coal Industry Retiree Health Benefit Act of 1992 on a coal company
that last operated in 1965. The legislation required the company to pay
into a new retirement fund, to provide lifetime benefits for widows of
employees who had worked for the company 30 to 50 years prior to the
legislation's enactment. The case is extraordinary, in that there was
no taking of specific property or assets of the company, but rather
imposition of financial liability that would amount to many millions of
dollars. The Supreme Court reached beyond previous case law to apply
the Takings Clause to a statute that placed such a ``severe,
disproportionate, and extremely retroactive'' burden as to upset
``fundamental notions of justice.'' 118 S.Ct. at 2152. The decision
essentially involved application of the principles behind the Ex Post
Facto Clause of Article 1, Sec. 9, clause 3 of the U.S. Constitution,
prohibiting retroactive criminal sanctions, to the retroactive
imposition of liability in a non-criminal setting, by deeming such
liability to be a ``taking.'' See 118 S.Ct. at 2151, citing Calder v.
Bull, 3 Dall. 386 (1798).
The Eastern Enterprise decision is not relevant in this rulemaking.
Nowhere in this rulemaking, including our disapproval of the phrase
``apportionment of the airshed,'' do we impose any financial liability
on MSCC, let alone a liability so burdensome that it might be construed
as a ``taking'' of MSCC's property. Nor is this rulemaking a form of
retroactive governmental action based on activity engaged in before the
effective date of the regulation, let alone one that ``improperly
places a severe, disproportionate, and extremely retroactive burden''
on MSCC, in the words of Eastern Enterprises, 118 S.Ct. at 2153. Our
action of partially approving the SIP has a prospective, rather than a
retroactive, effect on the federal enforceability of the Billings/
Laurel plan.
5. Constitutional Questions: Other
(a) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 13) raised various other constitutional challenges to our
proposed action, including interference with private contract; seizure
of private property or effects, infringement on equal protection under
the law; subjection to unusual punishment, double jeopardy, ex post
facto laws, or laws having the effect of bills of attainder; and
involuntary servitude.
Response: We regard these arguments as inapplicable to the matter
at hand. To the extent that we understand the arguments as raised in
the comment, they are either untimely or unfounded. The commenter's
argument that the Act may not authorize action by EPA that infringes on
MSCC's right to be afforded equal protection under the law, for
example, is untimely. Our partial disapproval only affects the federal
enforceability of the emission limitation for MSCC's 100-meter stack.
It is premature to claim that a federally enforceable emission
limitation for MSCC would so unfairly burden MSCC in comparison with
other sources in the area as to violate the guarantee of equal
protection provided by the Fifth Amendment through incorporation of the
Fourteenth Amendment to the U.S. Constitution. We have not yet proposed
a federally enforceable limitation for MSCC.
(b) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 1, pp. 3 and 4; comment # 13) stated that our actions have
interfered with MSCC's contract rights created in the 1977, 1996, and
1998 stipulations with the State. In particular, the commenter claims
that we have impaired MSCC's rights to good engineering design credit
for the 100-meter stack, protection from non-validated modeling, and a
guaranteed level of SO2 emissions.
Response: One premise of the comment seems to be that MSCC has an
entitlement or contract right to a 100-meter stack based on a 1977
State determination of GEP, and a State stipulation based on that
determination. However, our 1985 stack height regulations specifically
provided for varying degrees of ``grandfathering'' for stacks built
before certain dates. For reasons unknown to us, MSCC did not actually
start building its 100-meter stack until late 1993 (document # IV.A-17,
exhibit #37), and, thus, under our 1985 stack height regulations, the
stack does not qualify for any form of grandfathering. Various
industrial sources challenged our 1985 stack height regulations on
grounds similar to or the same as those raised by the commenter. The
Court of Appeals for the D.C. Circuit rejected these challenges. NRDC
v. Thomas, 838 F.2d
[[Page 22195]]
1224, 1249-1251 (D.C. Cir. 1988). Under section 307(b) of the Act, it
is also too late for MSCC to attempt to resurrect these failed
arguments. Thus, we do not believe MSCC has an entitlement or contract
right to a 100 meter stack height credit.
Also, assuming for the sake of argument that the stipulations
between MSCC and the State could be considered private contracts and
not governmental regulatory actions, the assertion that we have
unconstitutionally infringed on the rights created by such contracts is
without foundation. The Contract Clause of the U.S. Constitution,
Article 1, Sec. 10, clause 1, prohibits states from passing any ``law
impairing the obligation of contracts.'' It does not apply to Acts of
Congress, nor does the due process clause of the Fifth Amendment make
this prohibition applicable to a review of congressional legislation
(or, by implication, an agency action). See Washington Star Co. v.
International Typographical Union Negotiated Pension Plan, 729 F.2d
1502, 1507 (D.C. Cir. 1984). See also Eastern Enterprises v. Apfel, 118
S.Ct. 2131, 2148 (1998) (``[c]ontracts, however express, cannot fetter
the constitutional authority of Congress,'' quoting Connolly v. Pension
Benefit Guaranty Corporation, 475 U.S. 211, 223-224, 106 S.Ct. 1018,
1025 (1986)).
In addition, as stated above, our disapproval of MSCC's emissions
limitations merely affects the federal enforceability of those
limitations and does not alter or interfere with MSCC's obligations or
rights under State law. So, the commenter's complaint is untimely in
any event.
(c) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 13) stated that our action or the Act infringes on various
other constitutional protections by effecting a seizure of private
effects, double jeopardy, cruel and unusual punishment, or by having
the effect of bills of attainer or ex post facto laws, or by creating
involuntary servitude.
Response: These constitutional challenges are also unfounded. The
protection against seizure of property or effects under the Fourth
Amendment pertains to the prohibition against ``unreasonable search and
seizure'' of evidence by law enforcement officers in a law enforcement
proceeding. This rulemaking does not involve an enforcement proceeding,
and no effects have been seized from any person. Similarly, the Fifth
Amendment's prohibition against double jeopardy for the same offense,
the Eighth Amendment's protection against cruel and unusual punishment,
and the prohibitions in Article 1, Sec. 9, clause 3, against bills of
attainder (imposing liability without judicial process) and ex post
facto laws (imposing criminal sanctions for acts engaged in prior to a
law's effective date) only concern the constitutionality of imposing
sanctions on individuals for unlawful acts. They are not applicable to
this rulemaking.
Finally, no individual has been compelled to labor for another, or
to engage involuntarily in any activity whatsoever, in violation of the
Thirteenth Amendment's prohibition against involuntary servitude. If
the commenter intended to refer to a servitude on the land, in the
sense of a burden on one property for the benefit of another, this too
is not relevant, because ``servitude on the land'' refers to the
creation of easements under common law, which does not apply to this
rulemaking.
(d) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 59) stated that the Act unconstitutionally deprives citizens
and the regulated community of effective recourse to the courts with
its broad prohibition of later challenges to rules.
Response: Reflecting Congress' interest in finality of agency
action, section 307(b) of the CAA requires that appeals of agency
action occur within sixty days of rule promulgation, or if grounds for
appeal arise after promulgation, within sixty days after such grounds
arise. The constitutionality of this limitation on challenges to agency
action has been upheld. See Lloyd A. Fry Roofing Co. v. EPA, 554 F.2d
885, (8th Cir. 1977).
6. Statutory Challenge
(a) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 3, 5, 7, 10, 11 and 15) stated that our proposed partial
approval of the Billings/Laurel SIP revisions is inappropriate because
the enforceable emission limitations adopted by the State exceed those
required by the Act; that we should approve only the provisions that
are federally required and should disapprove or otherwise remand the
rest of the SIP to the State.
Response: In general, section 116 of the Act provides that States
may adopt emission standards stricter than national standards. The
United States Supreme Court has interpreted this provision together
with section 110 of the Act to mean that States may submit
implementation plans more stringent than federal law requires and that
EPA must approve such plans if they meet the minimum requirements of
section 110(a). See Union Electric Co. v. Environmental Protection
Agency, 427 U.S. 246, 266, 96 S.Ct. 2518, 2529 (1976). In other words,
we do not have the option of disapproving more stringent state
requirements, but must approve them as long as they meet Act criteria
for SIPs.
It is difficult to say which, if any, SIP limitations are more
stringent than the Act requires. The Act does not actually establish
emission limitations for SIPs, but requires that the emission
limitations adopted by a State must be sufficient to ``assure that
national ambient air quality standards are achieved.'' See section
110(a)(2)(C) of the Act. The determination of sufficiency is made by a
modeling demonstration. See section 110(a)(2)(K) of the Act; see also
40 CFR 51.112, which provides that ``[t]he adequacy of a control
strategy shall be demonstrated by means of applicable air quality
models, data bases, and other requirements specified in the appendix W
of this part.'' The Act requires States both to attain and maintain the
standards. See section 110(k)(5) of the Act. The control strategy must
be demonstrated to protect the NAAQS in the present as well as in the
future, providing an allowance for some level of emissions growth.
(b) Comment: One commenter (MSCC letter, document #IV.A-19, comment
#1, 3rd page) stated that the levels of control imposed in the
Billings/Laurel SIP plan exceed the authority directly available to the
federal government in its regulation of interstate commerce.
Response: The federal government's authority to regulate air
pollution under the Commerce Clause of the Constitution has long been
established. See, e.g., District of Columbia v. Train, 521 F.2d 971,
988 (D.C. Cir. 1975); vacated and remanded on other grounds sub nom.
EPA v. Brown, 431 U.S. 99, 97 S.Ct 1635 (1977); Sierra Club v.
Environmental Protection Agency, 540 F.2d 1114, 1139 (D.C. Cir. 1976),
cert. den., 430 U.S. 959, 97 S.Ct. 1610 (1977). In Hodel, the Supreme
Court indicated its agreement with these decisions. See 452 U.S. at
282, 101 S.Ct. at 2363. The comment implies that our authority to
approve SIPs is limited to minimal protection of the NAAQS. The courts
have not interpreted the Act in this way and have not limited our
authority to approve SIPs to approval of only a minimum of protection.
See Union Electric Company v. Environmental Protection Agency, ibid.
See also Sierra Club, 540 F.2d at 1139 (``Regulation of air pollution
clearly is within the power of the federal government under the
commerce clause, and we can see no basis on which to distinguish
[[Page 22196]]
deterioration of air cleaner than national standards from pollution in
other contexts''). If Montana had submitted emission limitations that
could be shown by modeling to be more stringent than necessary to
attain and maintain the SO2 NAAQS, we would have to approve those
limitations as long as they satisfied other Act requirements.
7. Conditional Approval
(a) Comment: One commenter (Yellowstone Valley Citizens Council,
document # IV.A-29) expressed concern that the MDEQ might disregard any
timeframes proposed by us and feared that the State would drag its feet
in fulfilling its commitment to make revisions to the SIP. The
commenter suggested that we demand that the Racicot Administration
ensure timely execution of necessary changes to the SIP with clear
expectations and consequences for failure to implement these changes.
Response: On May 4, 2000 the Governor of Montana submitted a SIP
revision to fulfill the commitments on which the proposed conditional
approval was based. Since the Governor has fulfilled his commitment, we
believe it is not appropriate to finalize the conditional approval.
Instead, we will complete notice-and-comment rulemaking on those
portions of the July 29, 1998 submittal we proposed to conditionally
approve on July 28, 1999 and on all of the May 4, 2000 submittal.
F. Due Process for SIP Approval
On July 28, 1999 (64 FR 40791), we proposed action on the Billings/
Laurel SO2 SIP through informal rulemaking, as authorized by section
110(k) of the Act and the Administrative Procedures Act (APA), 5 U.S.C.
553.
Summary of Comments and Response
One commenter submitted comments on our rulemaking process
requesting more formal rulemaking procedures.
We have considered the comments received and still believe our
informal rulemaking process authorized by section 110(k) of the Act and
the Administrative Procedures Act (APA), 5 U.S.C. 553 is appropriate
and sufficient.
The following is a summary of the comments received and our
response to the comments.
(1) Comment: One commenter (Goetz letter, document #IV.A-18,
exhibit D, comment #VIII., p. 66) requested that we afford MSCC the
right to conduct discovery of our documents and cross-examine EPA
witnesses in this rulemaking, to satisfy substantial due process
procedural protections.
Response: Due process in the context of the SIP Call is discussed
in section V.A.2, above. We are taking action on the SIP Call and on
the Billings/Laurel SIP through informal rulemaking, as authorized by
section 110(k) of the Act and the Administrative Procedure Act (APA), 5
U.S.C. 553. The requirements of due process for this rulemaking are met
under those provisions by publication of a proposed rulemaking action
with an opportunity for submission of written comments to be considered
by the agency prior to taking final action.
Section 110 of the Act does not require hearings on the record, or
even a hearing and oral presentation of comments prior to issuing a
binding SIP Call or approval or disapproval of a SIP. See section
307(d) of the Act omitting SIP approvals from a long list of EPA
actions, including the promulgation or revision of a FIP, which are
subject to the requirement of section 307(d)(5) of an opportunity for
the oral presentation of views in addition to the submission of written
comments. Section 110 of the Act requires only the minimum procedural
requirements of section 553 of the APA, including public notice and
opportunity for submission of written comments. See Indiana & Michigan
Electric Co. v. Environmental Protection Agency, 509 F.2d 839, 846 (7th
Cir. 1975); Buckeye Power, Inc. v. EPA, 481 F.2d 162, 172 (6th Cir.
1973).
Even when an opportunity for hearing is required, as for
promulgation of a FIP, we are not required by statute to give regulated
entities the opportunity to cross-examine EPA witnesses in an
adjudicatory hearing. See Cleveland Electric Illuminating Co. v.
E.P.A., 572 F.2d 1150, 1157 (6th Cir. 1978), where petitioners sought
remand of our action on a FIP and a full evidentiary hearing, including
cross-examination of EPA witnesses. The Sixth Circuit declined,
stating:
Administrative rulemaking which is to be preceded by extensive
hearings where ``a party is entitled to present his case or defense
by oral or documentary evidence, to submit rebuttal evidence, and to
conduct such cross-examination as may be required for a full and
true disclosure of the facts . . .'' (5 U.S.C. Sec. 556(d) (1967) is
required only when the last sentence of section 553(c) of the APA
applies. This section provides:
``When rules are required by statute to be made on the record
after opportunity for an agency hearing, sections 556 and 557 of
this title apply instead of this subsection.'' (Emphasis added). (5
U.S.C. Sec. 553(c)(1967)).
(Sections 556 and 557 of the APA outline the requirements for
extensive, adjudicatory-type hearings.)
572 F.2d at 1157, citing Buckeye Power, 481 F.2d at 172. In other
words, full-scale evidentiary hearings that allow for presentation of
evidence and cross-examination of opposing witnesses are only required
when section 553(c) of the APA applies, and that section applies when
and only when ``rules are required by statute to be made on the record
after opportunity for an agency hearing.'' 5 U.S.C. 553(c). This
interpretation has been approved by the Supreme Court. See United
States v. Allegheny-Ludlum Steel Corp. 406 U.S. 742, 92 S.Ct. 1941
(1972).
The Act does not require rulemaking ``on the record after
opportunity for an agency hearing'' for a SIP Call or approval or
disapproval of a SIP or SIP revision, or indeed for any other
rulemaking. The requirement of section 307(d)(5) of an opportunity for
hearing, which applies to FIPs but not SIPs, only requires ``an
opportunity for the oral presentation of data, views, or arguments, in
addition to an opportunity to make written submissions,'' as well as a
record of the proceedings and an opportunity for submission of rebuttal
and supplementary information. The formal adjudicatory procedures of
sections 556 and 557 of the APA do not apply to this or any other EPA
rulemaking under the Act.
(2) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # VIII, p. 66) stated that even if the SIP approval
process does not normally require formal procedures, procedural
requirements should not be treated rigidly and traditional procedures
may not be automatically adequate to provide due process (citing Walter
Holm & Co. v. Hardin, 449 F.2d 1009, 1015 (D.C. Cir 1971); O'Donnell v.
Shaffer, 491 F.2d 59, 52 (D.C. Cir. 1974); Seacoast Anti-Pollution
League v. Costle, 572 F.2d 872 (1st Cir. 1978) (ordering a remand of
our permit decision under the Clean Water Act for the limited purpose
of allowing the administrator to determine whether cross-examination
would be useful).
Response: These cases concern the interpretation of statutory
procedural requirements other than Clean Air Act requirements. Two
other cases cited in the comment do concern the Clean Air Act but are
not controlling: Kennecott Copper Corp. v. Environmental Protection
Agency, 462 F.2d 846, 850 (D.C. Cir. 1972)(stating that ``there are
contexts . . . in which the minimum requirements of the Administrative
Procedure Act may not be sufficient'' and remanding the SO2 secondary
standards to the Administrator for a statement explaining how he
derived
[[Page 22197]]
the standard); Bunker Hill Co. v. Environmental Protection Agency, 572
F.2d 1286 (9th Cir. 1977)(remanding a SIP rulemaking for hearing with
right of cross-examination, discussed below).
(3) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, comment # VIII, p. 66) stated that MSCC is entitled to
greater procedural protections in this rulemaking, because much of the
focus is on one party (MSCC) in a matter involving factual disputes and
requiring the resolution of highly complex and technical issues.
Response: Our partial disapproval of the SIP is not limited only to
issues involving MSCC's 100-meter stack. We are also disapproving the
SIP in part for failure to establish an enforceable limitation on flare
emissions. This aspect of our partial disapproval involves three other
sources in addition to MSCC. The stack height issue itself, where the
focus is on MSCC, involves our interpretation of our stack height
regulation, primarily a question of law. In any case, as the Cleveland
Electric Illuminating Co. court noted, typically the decisions which
Congress assigns to administrative agencies are of the type that would
be called technical and complex; yet Congress and the Supreme Court
have not given courts the responsibility to pick and choose agency
hearing procedures based on the complexity of the questions presented.
See 572 F.2d at 1160.
In a few cases, the courts have granted more extensive procedural
protections than those required by statute. In Bunker Hill Co. v.
Environmental Protection Agency, the Ninth Circuit required a formal
evidentiary hearing with cross-examination of witnesses in a remand of
our disapproval of a SIP control strategy for a lead smelter. 572 F.2d
at 1305. The state plan imposed 72 percent control of SO2 emissions
from a lead smelter; the court found that we were ``substituting
standards that would guarantee 82 percent control.'' Id. at 1291.
Apparently, we promulgated federal emission limitations for the source,
although it is not clear from the opinion whether we promulgated a FIP.
In Bunker Hill, the company objected that our emission limitations were
technologically and economically infeasible. The court remanded the
matter to us to further consider the technological feasibility of our
proposed limitations and required us to allow the company to cross-
examine our experts on the technological feasibility of the proposed
control measures. Id. at 1305. The Ninth Circuit stated that cross-
examination was not strictly required by the APA, since we were not
conducting rulemaking ``on the record,'' but that cross-examination
would ``help crystalize the varying contentions of the experts'' on
complex technical issues and aid the court in reviewing final action.
Id.
In contrast to the rulemaking in Bunker Hill, this rulemaking is
simply an approval and disapproval action on a SIP. We are not
promulgating or imposing already promulgated federal emission
limitations. By our rulemaking, MSCC will not be subject to limitations
more stringent than the requirements of the State SIP, and those
requirements are not disturbed by this rulemaking. Nor is there any
claim that MSCC is being subjected to requirements that are
technologically infeasible. Thus, there is no apparent need to
crystallize the contentions of experts on factual matters of a ``highly
complex and technical nature'' in order to aid a court in reviewing our
decision. The same due process concerns the Ninth Circuit found in
Bunker Hill are not at play in this rulemaking. Just as the Cleveland
Electric Illuminating Co. court observed, when it declined to follow
the example of the Bunker Hill opinion, we do not find ``any legal
requirement or practical need'' for a hearing, with or without cross-
examination. See 572 F.2d at 1160.
The other case the commenter cited as requiring cross-examination
in a rulemaking that was not ``on the record,'' Marine Space
Enclosures, Inc. v. Federal Maritime Comm'n., 420 F.2d 577 (D.C. Cir.
1969), concerns a decision by the Federal Maritime Commission, under
the Shipping Act of 1916, to award a contract for constructing a
maritime passenger terminal. The statute, as interpreted by the court,
required a hearing prior to decision. The D.C. Circuit remanded for a
public hearing, but did not require the commission to provide the
opportunity for cross-examination, saying that the issues might be
adequately developed more informally: ``we refrain at this juncture
from specifying that our remand order requires an evidentiary
hearing.'' 420 F.2d at 890. Even the decision in that case that a
hearing was required does not appear pertinent to this rulemaking,
where the Clean Air Act does not require one.
We decline to grant an opportunity for hearing in this rulemaking.
The Clean Air Act and the APA do not require it. Nor do we believe that
any unusual due process concerns would impel us to override the usual
procedures mandated by statute and case law. The commenters who have
submitted written comments on our proposed rulemaking have exercised
the opportunity to present their views to us through that mechanism; a
full record has been prepared on which our rulemaking will be made
final, and the record provides an adequate basis for judicial review.
G. Escape Clause
We proposed to disapprove the escape clause (a provision in the SIP
that allows each source to withdraw its consent to the stipulation and
thus nullify the SIP as it pertains to that source) because, if sources
invoke the escape clause, the MDEQ would no longer have a plan to
implement.
Summary of Comments and Response
One commenter opposed and three commenters supported our proposed
action.
We have considered the comments received and still believe it is
appropriate to disapprove the escape clause as proposed.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 46 and 70) stated that disapproving the ``escape clause''
will render the SIP revision more stringent than the State intended and
interfere with the State's agreement with industry to be even-handed in
allocating the burdens of the SIP. That same commenter (MSCC letters,
document # IV.A-19, comment # 47 and document # IV.A-20, comment # 12)
stated that our disapproval of the escape clause should not have the
effect of making provisions of the stipulations federally enforceable
if they have been nullified by a source invoking the escape clause.
Other commenters (Yellowstone Valley Citizens Council letter, document
# IV.A-29, and Zaidlicz letter, document # IV.A-30) stated that the
escape clauses in all the stipulations must be disapproved. One
commenter (ExxonMobil letter, document # IV.A-28) stated that the
escape clause does not need to be included in the final EPA-approved
SIP, since the function of the escape clause was to allow all parties
to negotiate the SIP in good faith and ensure consistent SO2 control
strategies and is not needed now that the State has adopted the
stipulations.
Response: The escape clause in each stipulation allows each source
to withdraw its consent to the stipulation and thus nullify the SIP as
it pertains to that source, if the initial control strategy adopted by
the State (or EPA as a FIP) for any of the other affected sources in
the Billings/Laurel area is not ``substantially similar in its common
terms'' to the source in question's
[[Page 22198]]
stipulation and attached exhibit of emission limitations. The
opportunity to invoke the clause exists up to 60 days after receiving
written notice of the final adoption of the control strategy.
We have no authority under the Act to approve as part of a
federally enforceable SIP a provision that could render the SIP or any
part of it unenforceable or void. Section 110(k)(3) of the Act
authorizes us to approve a SIP if it meets all the applicable
requirements of the Act, including the requirement of enforceable
emission limitations under section 110(a) of the Act. Other than
disapproving the escape clause as part of a partial disapproval of the
SIP, our only option in the face of it is to disapprove the entire SIP,
a course of action we are confident the State would not prefer us to
take. Instead, by disapproving the escape clause, we are meeting the
requirements of the Act and ensuring the federal enforceability of the
approvable portions of the SIP, without in any way changing the
substantive SIP requirements or creating new requirements. There may be
some question about the State's ability to enforce the SIP if the
escape clause is invoked. In our proposed rulemaking action, we stated
that if any source invoked the escape clause, we would issue a SIP Call
or take other appropriate action under the Act to address the resulting
inadequacy of the State's plan.
This aspect of our partial disapproval does not impermissibly make
the SIP more stringent than the State intended. Readers are referred to
the discussion of the effect of our partial approval/partial
disapproval in section V.E., above. The State carried out its intended
allocation of the burdens of the control strategy when it established
emission limitations for each of the sources in their respective
stipulations. Our disapproval of the escape clause does not disturb
these state decisions. The state-enforceable stipulations and all their
terms and conditions, including the escape clause, remain in effect at
the state level.
(2) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 123) stated that disapproval of the escape clause appears to
be a usurpation of a court function by changing a contract, based on
the representations of one party to the contract (apparently, referring
to the State).
Response: To the extent that we understand the commenter, it
appears to invoke the same concern referred to earlier that our action
interferes with a private right of contract in violation of the
Constitution. The reader is referred to the discussion of
constitutional challenges to our partial disapproval in section V.E.,
above. Alternatively, the commenter may object to our interpretation of
the escape clause on the basis that the clause is a contractual right
which only a court can interpret. In this rulemaking, we are
interpreting the escape clause as a provision of the SIP which affects
the adequacy of that plan, in light of the statutory criteria that
govern our approval action. Courts have ruled that our interpretation
of the provisions of SIPs is entitled to deference. See, e.g., American
Cyanamid Co. v. Environmental Protection Agency, 810 F.2d 493, 498 (5th
Cir. 1987); American Lung Ass'n of N.J. v. Kean, 670 F.Supp 1285, 1291
(D.N.J. 1987).
H. Language in ExxonMobil and MSCC Stipulations Related to
Incorporation of Earlier Stipulation and Apportionment of the Airshed
We proposed to disapprove language in ExxonMobil and MSCC's
stipulations related to incorporation of earlier stipulations and
apportionment of the airshed.
Summary of Comments and Response
Two commenters opposed and one commenter supported our proposed
action.
We have considered the comments received and still believe it is
appropriate to disapprove the language in ExxonMobil and MSCC's
stipulations related to incorporation of earlier stipulations and
apportionment of the airshed.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 81) stated that our disapproval of the two provisions of the
MSCC and ExxonMobil stipulations is inappropriate, because the State
case and settlement agreement are legal facts; our disapproval
overturns a state order by the MBER giving legal effect to the
settlement and to MSCC's contract rights. Another commenter (ExxonMobil
letter, document # IV.A-28) stated that they agreed that these
references should be deleted from the EPA-approved SIP.
Response: Our disapproval of paragraphs 1 and 2 of the MSCC
stipulation and paragraph 1 of the ExxonMobil stipulation does not
overturn the order of the MBER and does not affect the State's
agreement with ExxonMobil and MSCC. Excluding the reference to the
board order from the EPA-approved SIP clarifies that the order is not
federally enforceable, thereby avoiding any confusion that might have
ensued if we had included the reference in our approval. Our action
does not adversely affect MSCC's contract rights, because it does not
alter the settlement agreement.
(2) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 13) stated that our disapproval of the reference to the 1996
settlement between MSCC, ExxonMobil, and Montana is a selective attempt
to change the record in that case. The stipulation that resulted from
the settlement is not void or fully accomplished. The commenter stated
that if we believe that the reference should be removed because it is
not needed, then we should disapprove every other detailed requirement
not required by the Act and remand them all to the state.
Response: By disapproving the provisions related to the settlement
agreement, we do not attempt to revise the record. The public record of
the administrative case between MSCC, ExxonMobil, and the State is
found in the state-adopted SIP, where the provisions are included in
the MSCC and ExxonMobil stipulations. Our disapproval of these
provisions does not hinge on whether or not the February 1996
stipulation was accomplished or was necessary. Our disapproval stems
from our concern that including these provisions in the EPA-approved
SIP might imply that the settlement agreement itself is federally
enforceable. That result would be inappropriate, because we are
disapproving two SIP elements that directly resulted from the
agreement, the stack height demonstration and SO2 control plan for MSCC
with respect to the 100-meter stack. Approving the provisions that
reference the State's agreement on these issues could create confusion
about their possible federal enforceability and possibly conflict with
our explicit disapprovals.
(3) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 14, 16, and 81) stated that our position that no federally
cognizable right to emit exists is unreasonable; and that we have
approved emission rights for some sources but not for MSCC. Another
commenter (Goetz letter, document # IV.A-18, exhibit D, comment # VII,
p. 65) stated that our proposal not to approve the part of ExxonMobil's
and MSCC's stipulations related to apportionment of the airshed is
improper. These commenters (MSCC letter, document # IV.A-19, comment
#'s 43 and 51 and Goetz letter, document # IV.A-18, exhibit D, comment
# VII, p. 65) stated that, contrary to our position that an implied
[[Page 22199]]
right to pollute conflicts with the Act, the Act itself provides for
``emission rights'' and property rights in airsheds through emission
trading.
Response: In our proposed rulemaking action, we proposed to
disapprove paragraph 1 of the ExxonMobil and MSCC stipulations for an
additional reason, because the paragraph contained the statement that
the companies were entering into the settlement agreement, in part, to
preserve their respective ``rights to apportionment of the airshed.''
See 64 FR at 40800. We declared that this statement conflicts with the
purpose and obligations of the Act because air pollution sources do not
have an ownership interest in the ambient air or a right to pollute
under the Act. See id.
Our proposed disapproval of the statement about apportionment may
not have been artfully expressed. We did not mean to imply that we do
not recognize emission rights created by statute. The commenters are
correct that the Act authorizes various kinds of emission rights.
Section 110(a)(2) of the Act, for example, provides that SIPs may use
``auctions of emissions rights'' and other forms of emissions trading
as an enforceable emission control technique; Title IV of the Act
authorizes trading in emission allowances under the acid rain program.
Permanent and enforceable emission reductions may also be sold as
offsets for purposes of allowing sources to construct or modify under
new source review under part C (attainment areas) and part D (non-
attainment areas) of title I of the Act.
Such statutory rights to emit pollutants are not permanent, but may
be changed by regulatory action. In a future SIP revision, the State
might choose to redistribute some of the burden of SO2 control in the
Billings/Laurel area to achieve a different policy goal. Because the
rights are created by and can be diminished by regulatory action, they
are not the kind of private property protected under the Fifth
Amendment to the Constitution. See the discussion of takings and
emission rights in section V.E, above.
The phrase ``rights to apportionment of the airshed'' implies
possessory rights to the ambient air, as if the State or the United
States could allocate the atmosphere, like land or mineral rights, to
competing claimants. We were concerned that the phrase might imply
rights less conditional than those actually created under the Act and
that, if we approved this language into the federally enforceable SIP,
our approval might imply that ExxonMobil or MSCC have unconditional
rights to emit at the levels established in the State stipulations,
regardless of the effect of our partial disapproval of the SIP.
I. Default Approval of SIP
We proposed action on the Billings/Laurel SO2 SIP on July 28, 1999.
Summary of Comments and Response
One commenter submitted comments regarding default approval of the
SIP.
We have considered the comments received and do not agree with the
commenter.
The following is a summary of the comments received and our
response to the comments.
(1) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 57 and 124) stated that more than one year has elapsed from
the date of the Governor's submission of the SIP revisions for the
Billings/Laurel area before we published the proposed rule to approve,
disapprove, and conditionally approve the SIP. The commenter believes
that our failure to take final action on the SIP may have resulted in
automatic statutory approval of the submission. A proposed action is
not a final action.
Response: The SIP revisions submitted by the State have not been
approved by default. The requirements for our action on a SIP
submission are found in section 110(k) of the Act. Section 110(k)(1)
requires us to make a completeness finding within 60 days of receipt of
a SIP or SIP revision, or the submission will be deemed complete six
months after it is submitted. If the plan is complete, section
110(k)(2) requires us to take appropriate action within 12 months of
the completeness finding or the date the submission is deemed complete.
The Billings/Laurel SIP revisions were finally submitted on July 29,
1998. We did not make a completeness determination on this submission.
The revision was deemed complete as a matter of law on January 29,
1999; the twelve-month deadline for action would be January 29, 2000.
We proposed to approve the revisions in part, disapprove them in part,
and conditionally approve other parts on July 28, 1999.
The commenter is correct that the deadline for action is met, not
by publishing a proposed action, but by final rulemaking. The commenter
is incorrect in suggesting that failure to meet the 12-month deadline
means that the SIP submission is approved by default. The Act does not
authorize default approval of a SIP; SIPs must be approved under
sections 110(k)(3) and (4) of the Act. These provisions require our
affirmative action to approve or disapprove through rulemaking, after
public notice and opportunity for comment.
J. Department Discretion
We proposed to partially approve the SIP because the State had
addressed our earlier concerns with director discretion provisions in
the SIP. Our proposal was based on the July 1998 submittal of the SIP
and our interpretation of the modification process.
Summary of Comments and Response
One commenter opposed and two commenters supported our proposed
action.
We have considered the comments received and still believe it is
appropriate to partially approve the SIP as submitted since the State
had addressed our earlier concerns with director discretion provisions.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 69) stated that it is unnecessary under the Act to obtain our
approval for exercises of state discretion allowed by the SIP. The
commenter believes that Montana should be free to implement changes as
``necessary and expedient''; in the unlikely event Montana implemented
a change which made the SIP inadequate, we could call for a SIP
revision. The commenter objects to the ``dual approval provisions'' of
the SIP as making the administrative change process unduly cumbersome.
Two other commenters (Yellowstone Valley Citizens Council letter,
document # IV.A-29, and Zaidlicz letter, document # IV.A-30) stated
that we must review every SIP language change.
Response: Section 110(i) of the Act prohibits states and EPA,
except in certain limited circumstances which do not apply to the
Billings/Laurel SIP, from taking any action to modify a requirement of
a SIP except by SIP revision. We do not agree that Montana or EPA
should be free to make changes in SIPs whenever ``necessary or
expedient.'' The Act requires that changes in SIP requirements must be
made by the SIP revision process, because that process gives the public
the opportunity to review and comment on the reasonableness and
adequacy of the requirements that are to be imposed, and gives us an
opportunity to review and approve all changes.
The Billings/Laurel SIP allows for an informal administrative
process for making certain clerical changes and for approving
alternative requirements in the SIP, primarily with respect to
monitoring. The State and we consider
[[Page 22200]]
these changes and approvals so insignificant that they may be made with
our approval but without public review, without contravening the intent
of section 110(i) of the Act. The SIP describes the process by which
the State will propose such changes and approvals for us to review and
approve before they can be implemented. If the process is used in
accordance with the clarifications we made in our proposed rulemaking
action (See 64 FR at 40796), we believe that it satisfies the intent of
section 110(i). Any change that does not qualify for the informal
approval process must be processed as a SIP revision under section
110(a)(2). EPA's ``White Paper Number 2 for Improved Implementation of
the Part 70 Operating Permits Program'' by Lydia N. Wegman, Office of
Air Quality Protection and Standards, dated March 5, 1996, allows for
an alternative mechanism for making changes to SIPs through the Title V
permit process (attachment to document # II.C-8).
We will review all changes to the language and implementation of
the Billings/Laurel SIP to ensure that they are the kinds of minor
administrative changes that are appropriate to make without a SIP
revision. This up-front process of review and approval will be less
cumbersome for the State and regulated industry than having us
undertake an after-the-fact inquiry into the appropriateness of a
particular change and then initiate a SIP Call, if we identify an
inadequacy.
K. Quarterly Data Recovery Rate (QDRR)
We proposed to approve the provisions pertaining to the quarterly
data recovery rate (QDRR) for the CEMS because the State had addressed
our earlier concerns with QDRR provisions in the SIP. Our proposal was
based on the July 1998 submittal of the SIP and our interpretation of
the QDRR requirements.
Summary of Comments and Response
One commenter opposed and four commenters supported our proposed
action.
We have considered the comments received and still believe it is
appropriate to partially approve the SIP as submitted since the State
had addressed our earlier concerns with QDRR provisions.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 71) objected to a statement by MDEQ that obtaining data 100
percent of the time is required under the SIP. This commenter believes
that this statement is not what MSCC agreed to; data may not always be
recoverable because of other requirements or events not under the
reasonable control of the source. Two commenters (Yellowstone Valley
Citizens Council letter, document # IV.A-29, and Zaidlicz letter,
document # IV.A-30) stated that they support 100 percent CEMS
availability, unless data loss is adequately justified. One commenter
(ExxonMobil letter, document # IV.A-28) agreed with our assessment for
QDRR. One commenter (McGarity letter, document # IV.B-1) stated that
missing data must be heavily penalized and suggested that information
on CEMS data availability should be instantaneously accessible to
Yellowstone County residents so they can participate in the compliance
assurance process. Finally, this commenter suggested that the regulated
industry must be required to develop an approved Quality Assurance
Control Plan (QAPP) for CEMS that addresses daily self zero and
calibration auditing and annual RATA.
Response: We agree that CEMS should be in operation and their data
retrievable at all times, unless failure to operate or other loss of
data is adequately justified. QDRR is the percentage of the time in
each quarter when CEMS are operating and generating valid hourly data
about SO2 emissions. The stipulations entered into between the State
and each source in the Billings/Laurel area originally set a QDRR of 90
percent and an allowance of up to 192 hours per quarter when CEMS data
could be unavailable without the State taking enforcement action. Given
the high reliability of CEMS when they are operated properly, we
believe that the goal for CEMS data recovery should be 100 percent.
Anything less than that should be excused only if the loss of data has
been documented and justified.
In the final version of the SIP, the State deleted the allowance
for 192 hours of missing CEMS data per quarter and explicitly required
the sources to use ``best efforts'' to achieve the highest QDRR that
would be technically feasible. The 90 percent QDRR remains in the
stipulations as a trigger level for state action as an assumed level of
technical feasibility. The State, EPA, and citizens can still take
action to enforce the CEMS data requirement when a source has met the
90 percent QDRR but is missing ten percent or less of CEMS data for a
quarter; i.e., when its data recovery rate is greater than 90 but less
than 100 percent. The source must show that the data loss was
documented at the time it occurred and was justified, for example,
because it was caused by a lightning strike, electrical power outage,
or other circumstance beyond the operator's control.
With respect to the QAPP, auditing and annual RATA comment, the
exhibit to the stipulations, and an attachment to the exhibit, for each
source contain CEM performance specification requirements for the SO2
and H2S CEMS and flow meters. These requirements include daily testing
and annual RATAs. In addition to the exhibit requirements for CEMS and
flow meters, other documents addressing CEMS operations are to be
developed. These documents include quality assurance plans and standard
operating procedures. These other documents are not being included in
the SIP. See discussion in section M below.
L. Effect of the Montana Voluntary Environmental Audit Act
We stated in our proposed rulemaking that Montana's audit privilege
and penalty immunity law, the Voluntary Environmental Audit Act, Mont.
Code Ann. Secs. 75-1-101 et seq. (1999), (H.B. 293, effective October
1, 1997) can affect only state enforcement and cannot have any impact
on federal enforcement authorities. We stated that our proposed action
should not be construed as making any determination or expressing any
position regarding the State's audit privilege and penalty immunity
law.
Summary of Comments and Response
One commenter expressed an opinion of how the State should
implement its audit privilege and penalty immunity law and EPA
oversight of the SIP.
We have considered the comment received and believe our statements
in our proposed rulemaking action on the State's audit privilege and
penalty immunity law are still appropriate.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (Yellowstone Valley Citizen's Council
letter, document # IV.A-29) stated that the State should implement
Montana's Environmental Voluntary Audit Act (``Audit Law'') in a manner
that prevents violations of federal law, and that we should be vigilant
in oversight of state enforcement of the SIP in cases where alleged
polluters invoke the immunity provisions of the Audit Law.
Response: Our concerns about the effect of the Audit Law on the
State's ability to enforce the SIP have been addressed by a formal
agreement with the State. On December 13, 1999, EPA and the State
entered into a Memorandum of Agreement (``MOA'')
[[Page 22201]]
(see document # IV.C-32) concerning the effects of the Audit Law on
state implementation and enforcement of all federal environmental
programs in Montana. EPA and the State agreed that, as long as the
State's legal interpretation of the Audit Law (as memorialized in a
November 25, 1998 letter from Governor Marc Racicot and Attorney
General Joseph Mazurek to EPA Regional Administrator William P.
Yellowtail) and the MOA are in effect, State programs have sufficient
authority to maintain or obtain delegation of federal environmental
programs. The MOA resolved any outstanding issues between the State and
EPA concerning our delegation or approval of federal programs in the
state of Montana, including SIP approvals. In our proposed rulemaking
action, we declared that the Audit Law affected only state enforcement
authorities and had no effect on the ability of EPA or citizens to
enforce the SIP under relevant provisions of the Act. See 64 FR at
40804. This view continues to be true. We agree with the comment that
we should exercise our oversight role with particular care when the
Audit Law is invoked by an owner or operator of a source seeking
immunity from civil or administrative penalties for violation of the
Billings/Laurel SIP.
M. Effect of State-Only Provisions
We stated in our proposed rulemaking that we were not acting on
State-only provisions that were not submitted as part of the SIP.
However, if we were to determine that the State-only provisions, as
implemented, appeared to constrain, or otherwise have a chilling effect
on the State enforcement of the SIP, we would reconsider our approval
or take other appropriate action under the Act.
Summary of Comments and Response
One commenter expressed a concern that the State-only provisions
might create loopholes for industrial sources to avoid enforcement.
We have considered the comments received and believe our statements
in our proposed rulemaking action on the State-only provisions are
still appropriate.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (Yellowstone Valley Citizen's Council
letter, document # IV.A-29) stated that the placement of certain
technical aspects of monitoring requirements and the flare provisions
in a ``state-only'' section of the stipulations created potential
loopholes for the industrial sources to avoid enforcement. The
commenter expressed concern that other technical issues might be hiding
in the state-only stipulations.
Response: The ``Additional State Requirements'' adopted by the MBER
in June 1998 include documents that were not incorporated into the SIP
submitted to us for approval in July 1998. These documents include
quality assurance plans and standard operating procedures manuals for
the CEMS for the Billings/Laurel sources, together with corrective
actions plans and alternative monitoring plans. We believe that the
exclusion of these documents from the federally enforceable SIP will
not have an adverse effect on the implementation or enforcement of SIP
requirements. We believe that the opposite could be true: inclusion of
the documents in the federally enforceable SIP might have adversely
impacted the ability of EPA and citizens to enforce the SIP, because
the documents contain department discretion provisions which could
potentially constrain enforcement efforts. For that reason, in our
proposed rulemaking action we expressed our concern that the state-only
provisions related to CEMS might limit or have a chilling effect on
state enforcement of the SIP and our intention to take appropriate
action under the Act, if we found that were true. See 64 FR at 40803--
40804. We intend to address the exclusion of flare provisions from the
SIP in a future FIP, as discussed in section V.C., above. We are
unaware of any other technical issues or potential loopholes that might
be contained in the state-only provisions.
N. Enforcement and MDEQ Staffing
In our Technical Support Document for our proposed Action on the
Billings/Laurel SO2 SIP (document # III.B-1), we proposed to approve
the Billings/Laurel SO2 SIP as meeting the ``enforcement program and
stationary source regulations'' requirements.
Summary of Comments and Response
Three commenters expressed the concern that MDEQ lack sufficient
resources to adequately implement and enforce the SIP.
We have considered the comments received and still believe it is
appropriate to conclude that the Billings/Laurel SO2 SIP meets the
``enforcement program and stationary source regulations'' requirements.
(1) Comment: Three commenters expressed the concern that MDEQ lacks
sufficient resources to adequately implement and enforce the SIP. Two
commenters (Yellowstone Valley Citizen's Council letter, document
# IV.A-29, and Zaidlicz, document # IV.A-30) stated that we must insure
that the SIP is enforceable and that the State will have adequate
resources allocated to effectively implement, monitor and police it.
One of these commenters stated that two MDEQ staff members are
responsible for the enforcement of air quality standards for eastern
Montana, where 70 percent of the air pollution sources and most of the
CEMS are located, and that the workload is too great for two people.
This commenter also indicated they supported a bill in the last Montana
legislative session to increase staff in eastern Montana, but MDEQ
testified against the bill and it was defeated. Finally, this commenter
stated that we should monitor SIP implementation carefully to safeguard
the goal of improving air quality in the Billings/Laurel area. The
other commenter expressed the concern that the MDEQ does not have
adequate resources and staff to track compliance and maintenance of the
Billings/Laurel SIP and other federally mandated air quality programs
being delegated for state jurisdiction and that this puts human health
and safety in jeopardy.
Another commenter (McGarity letter, document # IV.B-1) stated that
turnover and low staff salaries have left MDEQ in a shambles; MDEQ
staff is under-resourced and over-worked, and cannot be counted on to
develop and enforce complicated compliance plans. This commenter urged
us to keep it as simple as possible--no ``bells,'' no ``whistles,'' and
no parametric monitoring with statistical averaging over ill-defined
periods of time. This commenter also stated that we should seriously
consider assuming SO2 program responsibility until the MDEQ is in a
position to do an adequate job.
Response: Congress intended that states have primary responsibility
for implementing and enforcing their SIPs. We have an oversight
secondary role and may take enforcement action under section 113 of the
Act for violation of a SIP when a state does not take action or when
its action is considered ineffective. We intend to carry out our
oversight responsibility with particular care in the Billings/Laurel
area, where we have already identified potential concerns about the
practical enforceability of certain provisions of the SIP.
We have regular meetings with MDEQ to discuss all compliance issues
related to the Act. We review facilities with identified violations and
discuss the State's proposed or on-going action to address these
violations. There is no indication at this time that MDEQ is failing to
meet its responsibility to
[[Page 22202]]
monitor compliance and take appropriate enforcement with respect to the
federally enforceable SIP. These Billings/Laurel SIP revisions have not
been subject to our oversight until now, when this final partial
approval will make most of the provisions federally enforceable. We
will oversee the State's efforts to monitor compliance with the new
requirements after today's final rulemaking, with particular emphasis
on the variable emission limitations and the effects of state-only
provisions, which were identified in our proposed rulemaking. See 64 FR
at 40794-40795 and 40803-40804. If we find that the State lacks
adequate resources to pursue any violation of the Billings/Laurel SIP
or if a state enforcement response is inadequate, we will take
appropriate action.
O. Reasonably Available Control Measures (RACM) Including Reasonably
Available Control Technology (RACT) and Reasonable Further Progress
(RFP) at CENEX
We proposed to conclude that the RACM (including RACT) requirements
have not been met in the Laurel SO2 nonattainment area.
Summary of Comments and Response
Two comment letters contained comments pertaining to our proposal
on RACM (including RACT) and RFP. The two commenters stated we should
not be disapproving the SIP as it pertains to these requirements.
We have considered the comments received and still believe it is
appropriate to conclude that the RACM (including RACT) requirements
have not been met in the Laurel SO2 nonattainment area.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (Cenex letter, document # IV.A-26)
stated that since our concern regarding flares is a non-issue the
Laurel area has demonstrated compliance with the SO2 NAAQS and RACM/
RACT and RFP have been met.
Response: We do not believe our concerns regarding flares are a
non-issue. We still believe the attainment demonstration is not
approvable without enforceable emission limitations on flares. See our
response to flare-related comments in section V.C., above. As indicated
in our TSD (document # III.B-1), for SO2 we interpret RACM (including
RACT) as those control measures that are necessary for attainment of
the NAAQS. Section 171(1) of the Act defines RFP as the ``annual
incremental reductions in emissions * * * which are required for
purpose of ensuring attainment of the applicable NAAQS by the
applicable date.''
Since we believe that the State has not demonstrated attainment of
the SO2 NAAQS in Laurel because the SIP lacks enforceable limitations
for flares, we believe it is necessary to conclude that the RACM
(including RACT) and RFP requirements have not been met.
(2) Comment: One commenter (MSCC letter, document # IV.A-19,
comment
# 109) stated that proposing to disapprove the attainment demonstration
is not related to determining that RACM/RACT have not been met.
Response: See response to comment (1) above
(3) Comment: One commenter (MSCC letter, document # IV.A-19,
comment
# 110) stated that Laurel is in compliance with the NAAQS, that
modeling shows attainment of the NAAQS in Laurel, and that our
dissatisfaction with the Billings model should not impact our
determination about RFP.
Response: See response to comment (1) above. Additionally, our
disapproval of the attainment demonstration is not based entirely on
the Billings stack height issue. Therefore, the Billings area modeling
is not the sole reason why we believe it is necessary to conclude that
the RFP requirements have not been met.
P. MSCC'S Auxiliary Vent Stacks
We proposed to disapprove the emission limitation on the auxiliary
vent stacks because the SIP does not restrict the type of fuel burned
in the boilers and heaters when they are exhausting out the auxiliary
vent stacks.
Summary of Comments and Response
Three commenters submitted comments on our proposed action. One
commenter believes that adjustments should be made to MSCC's exhibit
and the other commenters believe we are being overly burdensome.
We have considered the comments received and still believe it is
appropriate to disapprove the emission limitation on the auxiliary vent
stacks because the SIP does not restrict the sulfur content of the fuel
burned in the boilers and heaters when they are exhausting out the
auxiliary vent stacks and does not contain a monitoring method that
would make the emission limitation practically enforceable.\21\
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\21\ In our proposed action on MSCC's auxiliary vent stacks we
indicated that we believed it was appropriate to disapprove the
emission limit on the auxiliary vent stacks because the SIP did not
restrict the type of fuel burned in the boilers and heaters when
exhausting out the auxiliary vent stacks. After reviewing the
comments received on our proposed action of MSCC's 30-meter stack
emission limit (see comments and responses in V.Q., below), we still
believe the auxiliary vent stack emission limitation should be
disapproved. However, in lieu of restricting the type of fuel
burned, we believe the SIP should restrict the sulfur content of the
fuel burned and provide a method for measuring the sulfur content of
that fuel, i.e., make the emission limit practically enforceable.
---------------------------------------------------------------------------
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (Simonich letter, document # IV.A-23,
comment # 4C) agrees that adjustments should be made to the SIP to
address auxiliary vent stacks.
Response: We agree with the commenter.
(2) Comment: The other commenters (Goetz letter, document # IV.A-
23, exhibit C; MSCC letter, document # IV.A-19, comment #'s 68, 80,
121; MSCC letter, document # IV.A-20, comment # 10B) stated that the
auxiliary vent stack sources are trivial and even if the limitations
were exceeded this would not harm the attainment of the NAAQS since
these vents are not contributing to the controlling receptor. One of
the commenters (MSCC letter, document # IV.A-19, comment #'s 80, 121;
MSCC letter, document # IV.A-20, comment # 10A) stated that our concern
regarding the potential for the auxiliary vent stacks to exceed their
emission limitation if fuel high in H2S were burned is not unique to
MSCC. The commenter stated we should strike the limitation rather than
add more burdens to the source. Commenters (MSCC letter, document #
IV.A-19, comment # 10C; Goetz letter, document # IV.A-23, exhibit C)
stated that having an emission limitation invites the question of how
are the emissions to be monitored and enforced, how is the gas to be
determined to be low sulfur or sweetened. One commenter (MSCC letter,
document # IV.A-19, comment #'s 10D, 10E) indicated that we never
raised this issue in prior discussions and that other local vents in
Yellowstone County are not covered by federally enforceable
limitations.
Response: Although the commenter believes the auxiliary vent stack
emissions are trivial, we assume that emission limitations on the
auxiliary vent stacks, along with the other emission limitations in the
SIP, were established to assure attainment of the NAAQS. Therefore, we
also assume that if any of the limitations are exceeded, attainment of
the NAAQS cannot be assured. Regardless of whether the
[[Page 22203]]
auxiliary vent stack emission limitations are needed for attainment,
the State included the auxiliary vent stack emission limitations in the
SIP as an enforceable control strategy. We are concerned whether the
emission limitations are truly enforceable and want to assure that they
are. There may be other local vent stacks in the Yellowstone County
area that do not contain specific emissions limitations in the SIP. We
believe the SIP does not need to contain emission limitations on other
local vent stacks but does need to contain emission limitations on the
MSCC auxiliary for two reasons. First, the MSCC auxiliary vent stacks
are part of a major source that is already being controlled in the SIP.
Second, we assume that the other local vent stacks are truly minor
sources and all these other minor sources' (e.g., local vent stacks)
emissions have been included in the background concentration used in
modeling. We typically include minor emission points (where the
emission point is the entire source) in the background concentration.
The commenter stated that the potential to violate the auxiliary
vent stack emission limitation if it burns fuel high in H2S is not
unique to MSCC. We are assuming that the commenter means that other
sources could burn fuel high in H2S and violate their limitations.
Although this is true, other sources controlled by the SIP have CEMS or
other methods to measure H2S or sulfur content in fuel burned and flow
of the fuel to heaters and boilers. Therefore, for the other sources
there is a better tool to assess whether emission limitations are being
met.
We realize that the emissions from the auxiliary vent stacks at
MSCC are not large. However, to assure that the emission limitation is
being met, we believe the sulfur content of fuel burned in the heaters
and boilers, when they are exhausting through the auxiliary vent
stacks, should be restricted and that compliance with the emission
limitation should be monitored by measuring the H2S concentration in
the fuel. The MSCC exhibit submitted as part of the SIP already
contains reporting provisions that require MSCC to submit quarterly
reports which include estimates of the 3-hour and 24-hour SO2 emissions
from the 30-meter stack and auxiliary vent stack (see document II.E-2,
sections 7(C)(1)(k) and (l) of the MSCC exhibit). MSCC will need to
know the H2S concentration of the fuel burned in the boilers and
heaters to be able to estimate the 3-hour and 24-hour SO2 emissions
from the auxiliary vent stacks. We do not envision that restricting the
sulfur content of fuel burned in the boilers and heaters when they are
venting out the auxiliary vent stacks and monitoring the H2S
concentration of the fuel burned will impose unduly burdensome
compliance or reporting requirements on MSCC.
Finally, we agree that we may not have raised this issue in prior
comments we provided the State on the SIP. We try to identify all our
concerns with SIPs when we review them in draft form. However, just
because we have not identified a potential problem with a draft SIP
does not preclude us from addressing that concern when the SIP is
submitted in final form. We understand that the earlier MSCC exhibits
(those submitted prior to the July 1998 submittal) adopted by the State
did not contain provisions to address the auxiliary vent stacks. Thus,
we did not have the chance to raise the issue until after the SIP was
submitted.
Q. MSCC's 30-Meter Stack
We proposed to approve the SIP as it applies to MSCC's 30-meter
stack emission limitation for SO2, even though the 30-meter stack does
not have a CEMS or parametric monitoring system. Our proposed approval
relied on the fact that the SIP restricts the units that can exhaust
through the 30-meter stack to certain boilers and heaters, which may
only burn low sulfur fuel gas or natural gas. We believed that the fuel
limitation on the boilers and heaters would assure compliance with the
emission limitation. The sulfur concentration in natural gas is
generally low enough, we believe, to assure compliance with the SO2
limitation. However, as we stated in our proposal, we were concerned
that the SIP does not provide a definition of the term ``low sulfur
fuel gas.'' We proposed to interpret the term ``low sulfur fuel gas''
to mean ``properly sweetened fuel gas.'' The MDEQ indicated to us that
MSCC supplies the same sweetened refinery fuel gas it burns in its
boilers and heaters to the ExxonMobil refinery, and that concentrations
of H2S in the refinery fuel gas at ExxonMobil measure less than 100 ppm
under normal operating conditions. Our proposed approval thus relied on
our interpretation of the term ``low sulfur fuel gas'' and some
assurance about the levels of H2S in the fuel gas MSCC burns in its
boilers. In our proposal, we stated that we might create a definition
for the term ``low sulfur fuel gas'' when we promulgated a FIP to fill
in the gaps for SIP provisions we were proposing to disapprove.
Summary of Comments and Response
We received two comments pertaining to our interpretation of ``low
sulfur fuel gas.'' One commenter suggested that we approve a specific
definition of the term, while the other commenter objected to our
interpretation.
We have considered the comments received and, on further
investigation, conclude that our interpretation of the term ``low
sulfur fuel gas'' to mean properly sweetened fuel gas is not sufficient
to assure compliance with the 30-meter stack limitation at MSCC.
Because the 30-meter stack lacks a CEMS, parametric monitoring system,
or other reliable compliance monitoring method, in this final action we
are limitedly approving the emission limitation on the 30-meter stack
for its strengthening effect on the SIP, but are limitedly disapproving
the limitation for its lack of a compliance monitoring method.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (Zaidlicz letter, document #IV.A-30)
stated that the definition of ``low sulfur content'' should be no more
than 30 ppm, rather than the proposed 100 ppm.
Response: In our proposed approval we did not assign a numerical
value to the term ``low sulfur fuel gas.'' Instead, we relied on an
interpretation of the term as meaning ``properly sweetened fuel gas''
that has been treated in an amine unit to remove H2S. In acting on a
submitted SIP revision, we can only approve or disapprove the
requirements the State has adopted in the SIP. We have no authority, as
part of our approval or disapproval under section 110(k) of the Act, to
create a definition for an undefined term in the SIP.
In response to the comment, we investigated further to determine
what level of H2S concentrations would assure compliance with the 30-
meter stack limitation in the ``worst case.'' The State provided
calculations to show the H2S concentration in fuel gas that MSCC would
need to achieve in order to meet the 30-meter stack emission limitation
if all of the boilers and heaters allowed to vent to the 30-meter stack
were venting at the same time (see document # IV.C-23). The State found
that, to meet the emission limitation under these conditions the
maximum H2S concentration could not exceed 280 ppm, assuming a nominal
fuel gas value of 1,000 Btu's per standard cubic foot (Btu/scf). The
calculations indicate, however, that the nominal fuel gas value at MSCC
could be between 350 and 1500 Btu/scf. We re-ran the calculations,
[[Page 22204]]
assuming a worst-case nominal fuel gas value of 350 Btu/scf. We found
that, in order to meet the 30-meter stack emission limitation when all
five boilers and heaters are venting to the 30-meter stack at that
nominal fuel gas value, the maximum H2S concentration could not exceed
100 ppm (see document # IV.C-24).\22\ Thus it is not necessary to
restrict the concentrations to 30 ppm or less. The problem remains,
however, that ``low sulfur fuel gas'' is not defined in the SIP as
meaning fuel gas with H2S concentrations of 100 ppm or less. In
addition, MSCC does not have a monitoring system to measure H2S
concentrations in its fuel gas.
---------------------------------------------------------------------------
\22\ Our calculations were based on information received from
the DEQ on April 21, 1998 (document # IV.C-23). However, based on
MDEQ's Operating Permit Technical Review Document for MSCC's Title V
permit, the fuel burning potential of boilers H-1, H1-A, H1-1, and
H1-2, which may exhaust to the 30-meter stack, may be underestimated
by 15 percent of more (document # IV.C-75). Therefore, the H2S
concentration of the fuel gas may need to be less than the 1000 ppm
we calculated for the 30-meter stack emission limit to be achieved.
---------------------------------------------------------------------------
(2) Comment: The other commenter (MSCC letter, document # IV.A-19,
comment # 78; MSCC letter, document # IV.A-20, comment #11) objected to
our interpretation regarding ``properly sweetened fuel gas.'' The
commenter stated that our interpretation is unnecessary and leads to
further confusions. According to this commenter, even if the gas were
not properly sweetened, the stack could still meet its limit. The
commenter believes that MSCC has agreed not to vent the prior high SO2
emissions from the 30-meter stack, and that should be sufficient for
purposes of SIP approval. The commenter also believes that it is
``beyond reason'' to even limit the 30-meter stack and that we should
disapprove the SIP for establishing a limitation on such a minor
source. The commenter stated that the concept was to be gas meeting the
terms of the Montana sulfur in fuel rule, as clarified by the
stipulation.
Response: The commenter stated that it is unreasonable to even
limit the emissions from the 30-meter stack, because they are so minor.
We assume that the emission limitation on the 30-meter stack, along
with the other emission limitations in the SIP, was established to
assure attainment of the NAAQS. Therefore, we also assume that if any
of the emission limitations are exceeded, attainment of the NAAQS
cannot be assured. Regardless of whether the 30-meter stack emission
limitation is needed for attainment, the State believed it was
necessary to include the limitation in the SIP as an enforceable
control strategy.
Generally, when emission limitations are established in SIPs, we
require that the SIP contain methods to assure that the limitations are
being met and are enforceable. For the 30-meter stack limitation, the
SIP requires that MSCC report the date and time when emissions are
exhausted from the stack, the particular units that are exhausting from
the stack, and engineering estimates of emissions from the stack. More
specifically, the SIP limits the units (the particular boilers and
heaters) that can exhaust from the stack and the type of fuel (``low
sulfur fuel gas'' or natural gas) the boilers and heaters can burn when
they are exhausting out the 30-meter stack. We recognize that the
emissions from the 30-meter stack are not large. Nonetheless, in order
to assure that the emission limitation is being met at all times, we
believe that the type of fuel burned in the boilers and heaters when
they are exhausting through the 30-meter stack would need to be limited
and better defined.
Our proposed approval of MSCC's 30-meter stack limitation relied on
our interpretation of the term ``low sulfur fuel gas'' as meaning
``properly sweetened fuel gas'' which has been treated in an amine unit
to remove hydrogen sulfide. Both comments called this interpretation
into question. When we investigated further, we determined that
compliance with the 30-meter stack limitation can be assured if the
fuel gas burned in the boilers and heaters that exhaust to the stack is
limited to H2S concentrations of 100 ppm or less (see document #'s
IV.C-23 and IV.C-24).\23\ Not only is an interpretation or definition
of the term ``low sulfur fuel gas'' necessary to assure compliance with
the 30-meter stack emission limitation, the interpretation or
definition must also incorporate the notion that ``low sulfur'' fuel
gas has H2S concentrations of 100 ppm or less. MSCC, however, lacks a
monitoring system to measure H2S concentrations in the fuel gas burned
in the boilers and heaters that vent to the 30-meter stack, and so
lacks a method to assure that only ``low sulfur fuel gas'' is being
burned.
---------------------------------------------------------------------------
\23\ See footnote 22.
---------------------------------------------------------------------------
We tried to determine if an alternative method of measuring H2S
concentrations could be used. In its September 3, 1998 letter, the
State indicated that MSCC burns the same sweetened refinery fuel gas in
its boilers and heaters that it returns to ExxonMobil, implying that
the H2S concentration of the refinery fuel gas burned in MSCC's heaters
and boilers would be equivalent to the H2S concentration measured in
ExxonMobil's refinery fuel gas (see document # II.E-9). According to
the letter, available data from ExxonMobil's H2S monitors show that
ExxonMobil's refinery fuel gas rarely exceeds 100 ppm H2S. However, we
have since learned that, before ExxonMobil measures the H2S
concentration, it may dilute the refinery fuel gas it receives from
MSCC with natural gas (see document # IV.C-25). The H2S concentration
measured in ExxonMobil's refinery fuel gas thus could be lower than the
H2S concentration in the fuel gas burned in MSCC's heaters and boilers.
As a consequence, the H2S concentration of ExxonMobil's refinery fuel
gas cannot be used as an indicator of the H2S concentration of fuel gas
burned in MSCC's heaters and boilers; the H2S monitoring system at
ExxonMobil will not serve to assure compliance with the emission
limitation on MSCC's 30-meter stack.
The commenter stated that the intention was that the gas would meet
the terms of the Montana sulfur in fuel rule as clarified by the
stipulation. Montana's sulfur in fuel rule, found in the Administrative
Rules of Montana (ARM) 17.8.322, limits the sulfur content of liquid,
solid or gaseous fuels burned. MSCC's stipulation, paragraph 14,
modifies ARM 17.8.322 to ``mean that no person shall burn solid,
liquid, or gaseous fuels such that the aggregate sulfur content of all
fuels burned within a plant during any day exceeds one pound of sulfur
per million BTU fired. The rule shall be interpreted to allow for a
daily deviation of 0.1 pound of sulfur per million BTU fired. The rule
shall be interpreted to allow the blending of all fuels burned in a
plant during a given time period in determining the aggregate sulfur
content for purposes of the rule, and it shall not be construed to
require the blending or physical mixing of fuels at any given furnace
or heater within the plant complex.'' Because MSCC's stipulation
modifies how ARM 17.8.322 is interpreted, we do not understand how
relying upon the ``modified'' rule would address our concern.
Specifically, MSCC's stipulation interprets ARM 17.8.322 as applying on
a ``plant-wide'' basis. Therefore, boilers and heaters not vented to
the 30-meter stack would be considered in determining whether the
sulfur in fuel meets the rule. Additionally, MSCC's stipulation
indicates that the sulfur in fuel requirement is a ``daily''
requirement. MSCC could not assure compliance with a 3-hour emission
limit based on a daily requirement. Finally, even if the sulfur in fuel
rule is
[[Page 22205]]
controlling, the sulfur content in the fuel would still need to be
determined to assure compliance with the sulfur in fuel rule.
In response to the comments received and as a result of further
investigation of the issue, we conclude that the emission limitation
for MSCC's 30-meter stack is not practically enforceable. The
limitation on fuel for the heaters and boilers that vent to the stack
is not adequate to assure compliance with the emission limitation,
because the fuel limitation does not specifically limit the level of
H2S in the fuel and, in any case, MSCC lacks a method for measuring H2S
concentrations in the fuel. We are limitedly approving the emission
limitation for the 30-meter stack for its strengthening effect on the
SIP, but are limitedly disapproving the limitation for the lack of a
compliance monitoring method that would make the emission limitation
practically enforceable. In a later action, we intend to develop and
promulgate a compliance monitoring method for the emission limitation
for MSCC's 30-meter stack, when we complete a FIP to fill in the gaps
for the SIP provisions we are disapproving today.
R. ExxonMobil's and CENEX'S Refinery Fuel Gas Limitation
We proposed to conditionally approve the SIP as it applies to
ExxonMobil's refinery fuel-gas combustion emission limitations and
attendant compliance monitoring methods, in sections 3(A)(1), 3(B)(2),
4(B), and 6(B)(3) of ExxonMobil's exhibit, because the Governor
committed to address our concerns with the method for monitoring
compliance with the emission limitation. We also proposed to approve
Cenex's method for determining H2S in the refinery fuel gas.
On May 4, 2000 the Governor of Montana submitted a SIP revision to
fulfill the commitments on which the proposed conditional approval was
based.
Summary of Comments and Response
Five comment letters contained comments on our proposed action.
Three commenters believe we should place more requirements on sources.
One commenter agreed with our proposed conditional approval and one
commenter sought further clarification on several issues discussed in
our TSD.
We have considered the comments received. However, since the
Governor has fulfilled his commitment, we believe it is not appropriate
to finalize the conditional approval. Instead, we will complete notice-
and-comment rulemaking on parts of the July 29, 1998 submittal (i.e.,
those parts we proposed to conditionally approve on July 28, 1999) and
all of the May 4, 2000 submittal.
Even though we intend to complete separate rulemaking action on
parts of the July 29, 1998 and all of the May 4, 2000 submittal, below
we are responding to the comments received:
(1) Comment: Two commenters (YVCC letter, document # IV.A-29;
Zaidlicz letter, document # IV.A-30) stated we should set an H2S
limitation of 160 ppm (NSPS) on refinery fuel gas burned in heaters and
boilers; sources can meet a lower level. These commenters also stated
that methods for determining compliance with SO2 emission limitations
(H2S concentration and flow meters) can be nebulous and may be subject
to error particularly when the H2S concentrations exceed the level at
which the H2S CEMS can monitor and manual methods are used to determine
compliance. One commenter (McGarity letter, document # IV.B-1) stated
industry should be required to accept either fuel firing limitations on
process heaters and boilers or H2S concentration limitations (e.g., 160
ppm H2S).
Response: Two commenters stated our proposed action should go
further by setting H2S limitations on refinery fuel gas. As part of our
proposed action on the SIP, we cannot establish limitations more
stringent than the State submitted as part of its SIP. Under the SIP
process, we evaluate the State submittal to see if it meets the
requirements of the Act. We proposed to approve those provisions that
meet the Act and proposed to disapprove or conditionally approve those
provisions that do not measure up to the Act's requirements.
In the case of ExxonMobil's refinery fuel-gas combustion emission
limitation, the State has modeled this limitation, along with other
enforceable limitations in the SIP, and determined that the area will
attain the NAAQS. Under this SIP, we cannot require the State to do
more than adopt enforceable measures that will assure attainment of the
NAAQS.
These commenters also stated that the methods to determine
compliance with the fuel gas combustion emission limitations are
nebulous particularly when the H2S CEMS are over-ranged. We assume that
the commenters are referring to our proposed approval of Cenex's method
to determine H2S in the refinery fuel gas. Cenex is to use CEMS to
determine H2S concentrations. During times when the H2S concentration
exceeds the range the H2S CEM can monitor, Cenex is to initiate fuel
gas sampling analysis on a once per three hour period sampling
frequency using the Tutwiler method in 40 CFR 60.648 (or another method
approved by the MDEQ and EPA) to determine the H2S concentration.
We cannot require that CEMS always be used to monitor compliance
with emission limitations; other methods, if proven acceptable, can be
used. The CEMS and the Tutwiler method are methods that have been
adopted by us. Additionally, when the Tutwiler method is used, Cenex's
exhibit requires that it initiate fuel gas sampling analysis on a once
every three-hour period sampling frequency. Therefore, every three hour
period will be analyzed to monitor whether or not Cenex is in
compliance with its fuel gas combustion emission limitation. We
understand that the frequency at which the H2S CEMS frequency is over-
ranged is very low. Therefore, we believe the CEMS and the Tutwiler
method (used when the H2S concentration exceeds the level at which the
H2S CEMS can monitor), with 3-hour sampling, are acceptable methods to
monitor compliance with the emission limitations.
(2) Comment: One commenter (ExxonMobil letter, document # IV.A-28)
stated it is appropriate to conditionally approve its fuel gas
combustion emission limitation and attendant compliance monitoring
method.
Response: As mentioned above, since the Governor has fulfilled his
commitment, we are not finalizing the conditional approval. Instead, we
will complete separate rulemaking action on parts of the July 29, 1998
submittal (i.e., those parts we proposed to conditionally approve on
July 28, 1999) and all of the State's May 4, 2000 submittal.
(3) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 73, 74) wanted clarification on what we meant when we
indicated that 800 ppm is not controlling at ExxonMobil and its
significance. The commenter stated that the State determined that the
analyzer range is significant for its purposes. Secondly, the commenter
wanted to know what we meant when we alleged that ExxonMobil exceeded
its fuel gas limitation due to problems at MSCC.
Response: The commenter is correct that the State has determined
that the analyzer range is sufficient. In the State's May 4, 2000
submittal, the State has not revised ExxonMobil's exhibit to address
our concerns. We will address the May 4, 2000 submittal in a separate
rulemaking action.
[[Page 22206]]
One commenter wanted clarification on what we meant when we
indicated that 800 ppm is not controlling at ExxonMobil, and the
significance of that. The SO2 SIP limits the SO2 emissions from
combustion sources, not the concentration of H2S or other sulfur
compounds in the fuel burned. In the case of fuel gas combustion
sources, compliance with the limitation is monitored by knowing the
concentration of H2S in the fuel and the flow of the fuel to the
combustion sources (H2S concentration * flow rate * constant = lbs SO2/
hour). We learned, however, that there could be situations when the H2S
concentration in the fuel gas could exceed the level at which the H2S
CEMS could monitor. Therefore, sources could be exceeding the fuel gas
combustion limitation and the State and EPA wouldn't know because the
H2S CEMS would not record the true H2S concentration. We generally
believe section 110(a)(2)(A) of the Act requires that emissions
limitations in SIPS be enforceable at all times.
For Cenex, the SIP contains an alternative method to determine H2S
concentrations when H2S concentrations exceed the level the H2S CEMS
can monitor. For Conoco, we were less concerned about the range of
concentrations the H2S CEMS could monitor because all of Conoco's
boilers and heaters are limited by either new source performance
standards (NSPS) or a permit to a level equivalent to NSPS (i.e., 160
ppm of H2S). Therefore, Conoco's H2S CEMS may only be spanned to read
to 300 ppm and that is acceptable because any reading over 150 ppm
would be considered a violation.
Although ExxonMobil has spanned its H2S CEM to read between 1200 to
1300 ppm, we understand that there still could be situations when the
fuel gas could exceed the level at which ExxonMobil's H2S CEMS can
monitor. Also, there are no regulations or permits that require
ExxonMobil to limit the H2S ppm concentration in the refinery fuel gas
combusted in ExxonMobil's heaters and boilers. At one point, the State
believed its sulfur-in-fuel regulation would require ExxonMobil to meet
an H2S concentration of 800 ppm in the refinery fuel gas. However, the
Billings SIP modifies how the State's sulfur-in-fuel rule applies at
the Billings/Laurel sources and ExxonMobil is not required to meet the
H2S limitation of 800 ppm in its refinery fuel gas.
The commenter also wanted to know what we meant when we alleged
that ExxonMobil exceeded its fuel gas limitation due to problems at
MSCC. In our TSD (see document # III.B-1), we indicated that we were
aware that on several occasions during the summer of 1998, ExxonMobil
exceeded its fuel gas combustion limitation due to problems either at
MSCC or with ExxonMobil's amine unit. We became aware of the emission
limitation exceedance based on three letters ExxonMobil sent to the
MDEQ, on September 14, October 1, and October 30, 1998 (see document
#'s IV.C-19, 20 and 21, respectively). In those letters, ExxonMobil
indicated that on two separate occasions (one in July and one in
August, 1998) its fuel gas was not being properly treated. On one
occasion, MSCC was performing maintenance and ExxonMobil was switching
to its backup amine unit when ExxonMobil found that its fuel gas was
not properly treated. On the other occasion, a thunderstorm caused a
local power outage. MSCC was unable to treat ExxonMobil's refinery fuel
gas for 74 minutes. Those were the situations we were referring to in
our TSD.
S. Variable Emission Limitations
We proposed to approve the SIP as it applies to the variable
emission limitations at Montana Power and ExxonMobil. We proposed to
disapprove the SIP as it applies to the variable emission limitations
at MSCC due to the stack height issue. Our proposed approval for
Montana Power and ExxonMobil's variable limitation had several caveats.
If we were to find that the variable emission limitations are not
practically enforceable by the MDEQ or us, that the back-up monitoring
systems are not sufficient to assure on a regular basis that data are
available to determine the emission limitations, or that MDEQ is unable
to adequately review and assure the quality of the monitoring data on
which both limitations and compliance are based, we would reconsider
our approval.
Summary of Comments and Response
Four commenters submitted comments on our variable emission
proposal. One commenter questioned whether the State has the resources
to implement the variable emission limitations. Several commenters took
exception to our characterization of the variable emission limitation,
commenting that we portrayed the variable limitations negatively and
the commenters stated they should be portrayed in a positive manner.
Finally, several commenters wondered how we were going to address
MSCC's variable limitation when we adopt a FIP.
We have considered the comments received and still believe it is
appropriate to approve the SIP as it applies to the variable emission
limitations at Montana Power and ExxonMobil, with the caveats mentioned
in our proposal, and to disapprove the SIP as it applies to the
variable emission limitations at MSCC due to the stack height issue.
The following is a summary of the comments received and our
response to the comments:
(1) Comment: One commenter (Zaidlicz letter, document # IV.A-30)
stated that MDEQ does not have adequate resources to continually review
monitoring data for compliance with the variable emission limitations
at ExxonMobil, MSCC and Montana Power.
Response: Comments on MDEQ resources are being addressed
separately. See section V.N., above.
(2) Comment: Several commenters (Goetz letter, document # IV.A-18,
exhibit C; State letter, document # IV.A-23, comment # 4B) took
exception to our characterization of the air quality effect of the
variable emission limitations. The commenters stated our
characterization does not address the benefits of variable emission
limitations. For example, in the traditional approach to establishing
emission limitations through dispersion modeling, the emission
limitation is a function of an assumed buoyancy. Normally, a relatively
buoyant plume is assumed. With variable emission limitations, the
actual buoyancy of the plume is considered in establishing the emission
limitation. At low buoyancy flux, emissions are limited much more than
would occur in a normal SIP. One commenter stated that variable
emission limitations are more protective of the NAAQS. The commenters
stated variable emissions are a much superior approach to setting
emission limitations. One commenter stated that our concerns about the
variable limitation are inappropriate because of the practical nature
of the instrumentation used to determine compliance (instruments are
very reliable) and the modeling. The commenter stated the instruments
used to determine the buoyancy flux are very reliable and that the same
instruments used to determine compliance for a fixed limitation would
also be used to determine compliance with a variable limitation.
Response: As indicated in our proposed rulemaking, we evaluate SIPs
in relation to several provisions of the Act. In addition to looking at
air quality impacts of SIPs, we also need to assure that SIPs are
enforceable. Although we may agree with the commenters that the
variable emission limitations will result in fewer emissions when the
buoyancy
[[Page 22207]]
of the plume is lower, we also believe that variable limitations add a
level of complexity when trying to enforce. One commenter points out
that the same instruments would be used to determine compliance whether
the emission limitation was fixed or variable and that a variable
limitation should not make any difference. Although the same
instruments may be used to determine compliance whether the limitation
is fixed or variable, we believe that these instruments will be
generating significantly more information for variable limitations than
for fixed limitations. For example, in addition to confirming that the
source is in compliance with the limitation, agencies will also need to
confirm that the variable emission limitation was determined correctly.
Therefore, we believe that variable emission limitations increase the
workload and add a layer of complexity that is not found with fixed
emission limitations. Because of this enforcement complexity, we do not
agree with the commenters that variable emission limitations are a
superior approach to setting emission limitations.
However, we still believe it is appropriate to approve the variable
emission limitations in the SIP with a ``wait and see'' approach. As
indicated in our proposal, if we find it is too difficult to enforce,
we will reconsider our approval.
(3) Comment: Several commenters (State letter, document # IV.A-23,
comment # 4D; Goetz letter, document # IV.A-23, exhibit C; MSCC letter,
document # IV.A-19, comment # 44) stated that we should adopt variable
emission limitations for MSCC if we adopt a FIP for MSCC. One commenter
stated we should use the methodology laid out in the February 2, 1996
stipulation between ExxonMobil, MSCC and MDEQ, with more current CEM
data from MSCC, to develop the FIP. One commenter stated that since we
had not approved the variable limitation at MSCC, we had left a
question as to whether we would approve a variable limitation for MSCC
when we promulgated a FIP.
Response: We are only addressing the SIP, and not a FIP, at this
time. Therefore, comments pertaining to a FIP should be resubmitted in
response to a FIP proposal.
(4) Comment: Several commenters (State letter, document # IV.A-23,
comment # 4D; Goetz letter, document # IV.A-23, exhibit D; MSCC letter,
document # IV.A-19, comment #'s 45, 72, 122) stated we should make
clear in our approval of the SIP what should happen to MSCC's redundant
monitoring and data substitution requirements that are required in the
State's existing SIP. Some commenters stated that these requirements
were only needed for the variable limitation and that since we are not
approving the variable limitation, approving the redundant monitoring
and data substitution requirements would make the federally approved
SIP more stringent than the State intended. Commenters stated that any
FIP should also address the issues of redundant monitoring and data
substitution requirements.
Response: We assume that the commenters are referring to section
6(B)(3) of MSCC's exhibit which requires MSCC to install certain
monitoring equipment to support the use of variable emission
limitations. Since we proposed to disapprove the variable limitation at
MSCC, the commenters stated we should clarify our approval of these
provisions.
Section 6(B)(3) states, ``[b]y January 1, 1999, or a date 6 months
after EPA approval of the Buoyancy Flux monitoring contained in this
document (whichever date is later)* * *'' MSCC is to install and
maintain certain pieces of back-up monitoring equipment. Since we are
disapproving MSCC's variable emission limitation, we believe it does
not make sense to approve section 6(B)(3) of MSCC's exhibit because
section 6(B)(3)'s existence is conditioned on something that is not
happening. That is, we interpret section 6(B)(3) to apply only if we
approve MSCC's variable emissions limitation. Therefore, we are not
acting on section 6(B)(3) of MSCC's exhibit because we are disapproving
the variable emission limitations.
Finally, future FIP monitoring requirements will be addressed at a
later time.
(5) Comment: One commenter (Goetz letter, document # IV.A-23,
exhibit D) stated that our tentative approval of the variable emission
limitation is improper and amounts to unauthorized intrusion into the
primacy of the State's authority to allocate the ultimate mix of
emission controls in order to meet the NAAQS. The commenter also stated
that the partial approval leaves MSCC in limbo with no enforceable
emission limitation.
Response: We do not agree that we are tentatively approving the
variable emission limitation. As proposed, we are approving the
variable emission limitation at ExxonMobil and Montana Power and
disapproving it at MSCC. We do not believe we would be intruding on the
primacy of the State to select the strategies to attain the NAAQS by
partially approving and partially disapproving the plan. As indicated
earlier in the flare discussion (section V.C., above), the general air
quality management philosophy of the Act is that we establish NAAQS,
and States develop, and submit to us, control programs to attain and
maintain these NAAQS. We either approve or disapprove these control
programs and to the extent they are approved they are legally
enforceable by us and citizens under the Act. See also our discussion
in section V.E., above regarding comments on our partial approval of
the SIP.
We indicated in our proposal that we had concerns with the variable
emissions limitation, but that we were going forward with an approval.
Regardless of whether or not we stated in our proposed rulemaking
action our recourse for addressing any future concerns about the
variable emission limitation, the Act provides us with the authority to
require that the SIP be revised or to correct any action we later find
to be in error. Section 110(k)(5) says ``[w]henever the Administrator
finds that the applicable implementation plan for any area is
substantially inadequate to attain or maintain the relevant national
ambient air quality standard.* * * or to otherwise comply with any
requirement of this Act, the Administrator shall require the State to
revise the plan as necessary to correct such inadequacies* * *''
Section 110(k)(6) provides the authority to revise our action on a plan
if we find our action to be in error. Therefore, we do not believe our
approval of the variable emission limitation was tentative or improper.
Our proposal provided the State, sources and public with notice of our
concern about the variable limitations and our recourse should those
concerns come to fruition. The Act gives us the authority to address
any future problems with the variable emission limitation, or any other
aspect of this SIP, regardless of whether or not we identify our
concerns in our approval of the SIP.
Finally, the commenter stated that our partial approval leaves MSCC
in limbo with no enforceable emission limitation. Since we are
disapproving the emission limitations on the 100-meter stack, the
commenter is correct in that there will be no federally enforceable
emission limitations on the 100-meter stack. However, we intend to
address this issue by adopting a FIP. In the meantime, the 100-meter
stack is subject to State-enforceable limitations on the 100-meter
stack.
[[Page 22208]]
T. Minor Sources
In our TSD to our proposed rulemaking action (page 44), pertaining
to the discussion of MSCC's auxiliary vent stacks, we indicated that
the prior stipulations (those submitted prior to the July 29, 1998
submittal) appeared to provide an exemption for minor sources, which
the auxiliary vent stacks could be construed to be.
Summary of comments and responses
One commenter wanted further explanation of our comment. We are
providing that explanation below.
(1) Comment: One commenter (MSCC, letter, document # IV.A-19,
comment #79) requested that we explain what we meant on page 44 of our
technical support document where we indicated that the prior
stipulations (those submitted prior to the July 29, 1998 submittal)
appeared to provide an exemption for minor sources that possibly
included the auxiliary vent stacks. The commenter stated that there are
other minor sources that are exempt from the SIP, the nation has
millions of minor sources, and the prior SIPs as well as the existing
SIP are adequate to control minor sources at MSCC.
Response: We initially raised concerns about the auxiliary vent
stack emissions in our June 3, 1997 letter to Mark Simonich (see
document # II.C-8). Our concern was that the exhibit to the stipulation
(submitted by the Governor on August 27, 1996) appeared to only limit
the named heaters and boilers if they were vented to the 100-meter or
the 30-meter stack. If emissions from the named heaters and boilers
were vented out the auxiliary vent stacks, the heater and boilers were
only limited by the minor source provisions ;\24\ there were no
specific emission limitations on the heaters and boilers when vented
out the auxiliary vent stacks. Since the State believed it was
necessary to limit and model the 30-meter stack when the heaters and
boilers were vented to it, we were concerned that if all the emissions
from the heaters and boilers were vented to the auxiliary vent stacks,
which have lower stack heights than the 30-meter stack, then attainment
could not be assured.
---------------------------------------------------------------------------
\24\ We were also concerned that the minor source provisions (in
the exhibit submitted by the Governor on August 27, 1996) might not
apply to the auxiliary vent stacks because the minor source
provisions indicated that they applied to the ``control of emissions
of sulfur bearing gases from minor sources such as ducts, stacks,
valves, vessels, and flanges which are not otherwise subject to this
Exhibit A.'' Since the named heaters and boilers were already
subject to Exhibit A, we were concerned that the minor source
provisions might not apply to the auxiliary vent stacks at the named
heaters and boilers.
---------------------------------------------------------------------------
In his January 30, 1998 letter (see document # II.C-9), Mark
Simonich agreed that the SIP did not limit the emissions of the named
heaters and boilers when they are vented through their respective
auxiliary vent stacks. The letter indicated that MSCC and the
Department intended to model these emissions and modify the stipulation
as needed. The July 29, 1998 submittal contained the modeling
demonstration and revisions to the stipulation to address the auxiliary
vent stacks.
U. Compliance Determining Method--ExxonMobil's Coker CO-Boiler Stack
and F-2 Crude/Vacuum Heater Stack
We proposed to conditionally approve the SIP as it applies to the
coker CO-boiler stack emission limitation and F-2 crude/vacuum heater
stack emission limitations and the attendant compliance monitoring
method (sections 3(E)(4) and 4(E) (only as they apply to the F-2 crude/
vacuum heater stack), 3(A)(2), 3(B)(1), 3(B)(3) and attachment 2 of
ExxonMobil's exhibit), based on the Governor's commitments to adopt a
compliance monitoring method for the coker CO-boiler stack emission
limitation and to revise attachment 2 (of the exhibit).
On May 4, 2000, the Governor of Montana submitted a SIP revision to
fulfill the commitment on which the proposed conditional approval was
based.
Summary of Comments and Responses
We received three comment letters on our proposed conditional
approval of ExxonMobil's coker CO-boiler stack emission limitation and
F-2 crude/vacuum heater stack emission limitations and the attendant
compliance monitoring method (sections 3(E)(4) and 4(E) (only as they
apply to the F-2 crude/vacuum heater stack), 3(A)(2), 3(B)(1), 3(B)(3)
and attachment 2.) Two commenters stated we should require CEMS on
ExxonMobil's coker CO-boiler stack and one of the commenters stated we
should have CEMS on the F-2 crude/vacuum heater stack. One commenter
agreed with our proposal.
We have considered the comments received. However, since the
Governor fulfilled his commitments, we believe it is not appropriate to
finalize the conditional approval. Instead, we will complete notice-
and-comment rulemaking on parts of the July 29, 1998 submittal (i.e.,
those parts we proposed conditional approval on July 28, 1999) and all
of the May 4, 2000 submittal.
Even though we intend to complete separate rulemaking action on
parts of the July 29, 1998 submittal and all of the May 4, 2000
submittal, below we are responding to the comments received:
(1) Comment: Two commenters (Zaidlicz letter, document # IV.A-30
and McGarity letter, document # IV.B-1) stated ExxonMobil's coker CO-
boiler emission limitation should be enforced through CEMS. One
commenter (McGarity letter, document # IV.B-1) stated ExxonMobil's F-2
crude/vacuum heater stack should contain CEMS. The commenter stated SO2
compliance cannot be demonstrated with best engineering algorithms
unless all the H2S in the feed refinery fuel gas (including
sour water stripper emissions and other streams that are plumbed
upstream of the combustion unit) are regularly measured or there is an
SO2 CEMS.
Response: We cannot require that every emission point be enforced
through CEMS. Other methods, such as engineering calculation, are
acceptable if the State can demonstrate that the calculations are
representative of SO2 emissions. With the May 4, 2000 submittal, the
State has developed a method to monitor compliance with ExxonMobil's
coker CO-boiler emission limitation and is revising attachment 2 of
ExxonMobil's exhibit. We will evaluate the methods the State developed
in a separate rulemaking action.
(2) Comment: One commenter (ExxonMobil letter, document IV.A-28)
agreed with our assessment that the coker CO-boiler stack emission
limitation and F-2 crude/vacuum heater stack emission limitations and
the attendant compliance monitoring method should be conditionally
approved.
Response: As mentioned above, since the State has fulfilled its
commitment, we are not finalizing the conditional approval. Instead, we
will complete separate rulemaking action on parts of the July 29, 1998
submittal (i.e., those parts we proposed to conditionally approve on
July 28, 1999) and all of the State's May 4, 2000 submittal.
V. Effect of the 1990 Amendments to the Clean Air Act
(1) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 3.P) expressed a belief that the Clean Air Act amendments of
1990 superseded requirements for attainment demonstrations for SIPs for
three nonattainment areas in California under the prior Act and that we
could not take action on this SIP until we clarified the effect of the
1990 amendments on other
[[Page 22209]]
attainment demonstrations. The same commenter stated that EPA must
determine whether Montana needs to submit a SIP that relies on a
modeled attainment demonstration in light of the 1990 amendments. See
MSCC letter, document # IV.A-20, comment # 4.G.
Response: Generally, the 1990 amendments to the Clean Air Act do
not affect our pre-existing powers concerning the approval of plans or
plan revisions. Commonwealth of Pennsylvania Dept. of Environmental
Review v. Environmental Protection Agency, 932 F.2d 269, 272 (3rd Cir.
1991). We are uncertain what the commenter means when he states that
the amendments superseded requirements for attainment demonstrations
and that EPA must determine whether a modeled attainment demonstration
is necessary under the current Act. The 1990 amendments did not revise
the planning requirements for SO2. The 1990 amendments did revise the
planning requirements for three criteria pollutants: ozone, carbon
monoxide, and PM-10. See CAA title I, part D, subparts 2, 4, and 4
(sections 181 through 190 of the Act). We clarified the effect of these
extensive revisions with respect to various aspects of SIP development
in our published guidance titled ``General Preamble for the
Implementation of Title I of the Clean Air Act Amendments of 1990''
(``General Preamble''). See generally 57 FR 13497 (April 16, 1992)--
document # II.A-15.
The 1990 Act amendments that affected requirements for
nonattainment areas for ozone, for example, (Act title I, part D,
subpart 2, sections 181-185B) changed the attainment deadlines for
these areas and may have had an effect on several pending actions
against EPA related to our approval of SIPs for the Los Angeles area.
The 1990 amendments had a more limited effect on the planning
requirements for SO2. The amendments did not alter attainment deadlines
or establish new requirements for attainment demonstrations for SO2
SIPs, but simply required States with SO2 nonattainment areas to submit
a plan that complied with general planning requirements, including a
part D permit program for major new and modified sources. See section
191 of the Act. See also, General Preamble, 57 FR at 13546, where we
said that if a nonattainment SO2 plan had been approved for an area
before the 1990 Amendments and we subsequently found the plan to be
substantially inadequate, as we did for the Laurel nonattainment area,
the plan must be revised to provide for attainment within five years
from the finding of inadequacy. The State of Montana submitted the
required plan revision for the Laurel SO2 nonattainment area as part of
the SIP revisions for the Billings/Laurel area. Because of the direct
relationship between receptors and emission sources, the use of models
to demonstrate attainment of the SO2 NAAQS continues to be a necessary
and appropriate planning tool in SO2 nonattainment and SIP Call areas.
W. Stack Height Issues
In our July 28, 1999 action (64 FR 40791) we proposed to disapprove
MSCC's stack height credit and emissions limitations used in the
attainment demonstration modeling for the Billings/Laurel area. We also
proposed to disapprove MSCC'S emissions limitations because the State
set the limitations based on an amount of stack height credit for MSCC
(97.5 meters) that is not supportable under section 123 of the Act and
EPA's stack height regulations. Generally speaking, a source allowed
greater stack height credit will have less stringent emissions
limitations in the SIP. Such a source is able to rely to a greater
degree on dispersion, rather than emissions controls, to help ensure an
area meets the NAAQS.
Summary of Comments and Response
We received numerous comments on our proposal. Most of the comments
were from MSCC and its consultants. They objected to our proposed
disapproval of the stack height credit and emissions limitations for
MSCC. The State also submitted comments objecting to our proposal.
Several other commenters also submitted comments on this issue, some
objecting to our proposal and others favoring our proposal.
We have considered the comments received and still believe we
should finalize our proposed disapproval of the MSCC's stack height
credit and SRU 100-meter stack emissions limitations. None of the
adverse comments has convinced us that our interpretation of the Act
and our regulations is unreasonable or that we should change our
proposed course of action.
To assist the reader, we have attempted to separate the comments
and our responses into categories. Some comments and responses that
relate to stack height questions are contained in other sections of
this document--for example, comments that raise constitutional
questions are grouped with other comments based on the Constitution.
(See section V.E., above.)
The following is a summary of the comments received and our
response to the comments.
1. Issues Related to NSPS
Although the State approved above-formula stack height credit for
MSCC, and required MSCC to use an NSPS emission rate in the fluid
modeling demonstration that the State approved, the State did not
require MSCC to meet the NSPS emission rate in the SIP. As we described
in our proposed disapproval and TSD, we read the language of our stack
height regulations to require sources that wish to obtain above-formula
stack height credit to have a SIP limit that is no higher than the NSPS
limit used in fluid modeling. In the alternative, a source may justify
use of an alternative limit in fluid modeling by showing that it cannot
meet the NSPS limit. In this instance, a source would then have to have
a SIP limit no higher than this alternative limit. Such an alternative
limit would be determined through a Best Available Retrofit Technology
(BART) analysis pursuant to EPA guidance. We typically refer to such an
alternative limit as a ``BART limit.''
Because MSCC's emissions limitations in the SIP are not consistent
with the NSPS limit used in MSCC's above-formula fluid modeling, we
proposed to disapprove MSCC's 97.5 meter stack height credit and SRU
100-meter stack emissions limitations. We received numerous comments on
this issue and have considered them. Nothing in the comments has caused
us to change our position on this issue.
(a) Comment: One commenter (MSCC letter, document #IV.A-19, comment
#'s 20, 21, 89; MSCC letter, document #IV.A-20, comment #1.J) stated
that EPA should find that the State properly applied the explicit
provision of the rules for use of NSPS or other feasible emission rates
in the approved fluid modeling and that the State was not required to
impose the NSPS or other feasible emission rate as an ongoing operating
limit. The commenter claimed that the rule defines GEP without
reference to actual emission limits; that instead, GEP is properly used
to define emission limits under section 123 of the Act and EPA's
regulations, and to establish an emission limit before establishing GEP
is circular logic.
Response: We addressed these objections in the TSD to our proposal,
and we stand by that discussion--see TSD pages 61-66. We continue to
read the stack height regulations to require a source to at least meet
the NSPS/BART limit as a condition of obtaining above-formula stack
height credit. Establishing an upper bound for an emission limit
[[Page 22210]]
before establishing GEP stack height is not circular. It merely
reflects EPA's conscious decision to limit situations in which sources
would want or need above-formula stack height credit and to restrict
such credit to sources that would be well-controlled as EPA decided to
define that term. EPA's approach was entirely consistent with Congress'
intent that above-formula stack height credit should be granted only in
rare circumstances and with utmost caution. See NRDC v. Thomas, 838
F.2d 1224, 1242; Sierra Club v. EPA, 719 F.2d 436, 450.
In addition to the language we cited in our TSD, there is
additional preamble language that is relevant to this issue. Under the
heading, ``Summary of Modifications to EPA's Proposal Resulting from
Public Comments'', we stated the following:
``Section 51.1(ii)(3) (should refer to (kk)(1)) has been revised as
discussed elsewhere in this notice to specify that an emission rate
equivalent to NSPS must be met before a source may conduct fluid
modeling to justify stack height credit in excess of that permitted
by the GEP formulae.''
50 FR 27905, July 8, 1985, emphasis added. Again, it is clear that the
NSPS rate was not intended as a mere modeling assumption.
(b) Comment: One commenter (State letter, document #IV.A-23, pp.
17-19) stated that the rule and section 123 contain no requirement that
a source must meet the NSPS limit on an ongoing basis. The commenter
claimed that the rules and section 123 pertain to the determination of
GEP stack height and do not impose the NSPS limit or any other emission
limit. According to the commenter, the term ``allowable emission'' does
not create the requirement EPA says it does, particularly given the
context in which it is found.
Response: We disagree with the commenter regarding our rule and the
use of the term ``allowable emission.'' See our response to the
previous comment. We agree that section 123 does not impose an emission
limit for granting above-formula stack height credit. The D.C. Circuit
recognized this, but held that EPA had the discretion under 123 to
apply control-first in the above-formula context. NRDC v. Thomas, 838
F.2d 1224, 1241 (D.C. Cir. 1988). This is what EPA did, by requiring
that a source granted above-formula stack height credit meet the NSPS
or BART alternative rate as an ongoing limit. The State's reading of
the regulation would read the term ``allowable'' out of the regulation,
but this language cannot be ignored. See, e.g., Market Co. v. Hoffman,
101 U.S. 112, 115--116 (1879); Reiter v. Sonotone Corp., 442 U.S. 330,
339 (1979).
In addition, the context must be considered. Our interpretation is
consistent with the form of the proposed regulation. In the proposal,
we proposed the use of one of three emission rates in the fluid
modeling demonstration. It is clear from the following language from
the proposal that we used the terms ``emission rate'' and ``emission
limitation'' interchangeably and that we viewed the emission rate used
in fluid modeling demonstrations as an upper bound for subsequent
emission limits:
``It was not necessary under the previous definition of ``excessive
concentrations'' to establish a source emission limitation prior to
conducting fluid modeling because the definition required only that
sources show an increase in concentration due to downwash, wakes, or
eddy effects. With the revised definition, it will be necessary to
specify an emission rate in the fluid model, in order to determine
whether a NAAQS or PSD increment is being exceeded. Consequently,
the Agency will require in its technical support document that the
emission limitation be established based on either: (1) The
existing, approved emission limit; (2) any applicable technology-
based emission limit, such as the new source performance standards
(NSPS); or (3) the emission limit that would result from the use of
GEP formula stack height, whichever is applicable to the source
being modeled. Once the emission limitation is identified, fluid
modeling may consider the actual downwash, wake, and eddy effects of
nearby terrain features and structures on ground level
concentrations. Sources will then be allowed to calculate stack
height credit based on that height needed to eliminate excessive
concentrations caused by such effects.''
49 FR 44878, 44882, November 9, 1984.
We viewed the emission rate to be used in fluid modeling as a limit
on future emissions--in the Agency's view, the limit used in fluid
modeling and above-formula GEP stack height credit were inexorably
linked, and the above-formula stack height credit had no validity
unless the emission limit established prior to conducting fluid
modeling was honored. (As we discuss elsewhere, one way in which the
emission limit is honored is if the SIP establishes a lower limit based
on other factors or requirements that are more controlling than
downwash.)
(c) Comment: Two commenters (State letter, document #IV.A-23, p.
19; Goetz letter, document #IV.A-18, exhibit D, p. 23) stated that it
is inappropriate for EPA to rely on or resort to the preamble to the
stack height regulations or legislative history when the plain language
of the rules is clear. These commenters claimed that the preamble
should not be used to create ambiguity where none exists or to alter
the rule language. According to the commenters, the rules require use
of the NSPS limit in the fluid modeling demonstration but do not
address the emission limitation that will apply after the determination
of GEP stack height. One of the commenters (State) asserted that the
preamble language selected by EPA is unpersuasive and taken out of
context, and that other preamble text clearly supports the commenters'
position.
Response: As noted in our TSD (p. 61), the plain language of the
rule refers to the ``allowable emission rate'' to be used in the fluid
modeling demonstration, and the word ``allowable'' is used in our
regulations to denote an enforceable emission limit. The word
``allowable'' would be extraneous if we were merely trying to indicate
that the NSPS would be assumed for demonstration purposes. We believe
our intent was clear--the emission rate used in the fluid modeling
demonstration was not a mere assumption, but a cap on emissions that a
source would have to meet as a condition of obtaining above-formula
stack height credit. At the very least, the use of the term ``allowable
emission rate,'' combined with the possibility that a source could
justify an alternative emission rate in certain circumstances, renders
the regulation ambiguous and subject to reasonable interpretation by
EPA. See, e.g., Martin v. Occupational Safety & Health Review Comm'n,
499 U.S. 144, 150-151 (1991); Udall v. Tallman, 380 U.S. 1, 16 (1965);
Walker Stone Company, Inc. v. Secretary of Labor, 156 F.3d 1076, 1080
(10th Cir. 1998). This also makes it reasonable for us to consult other
documents implementing and interpreting the regulation. The preamble to
the regulation is particularly important for interpreting the
regulation because it was issued contemporaneously with the regulation
and was essential to meet the requirements of the Administrative
Procedure Act (providing EPA's basis for issuing the rule for purposes
of judicial review.) The preamble clearly explains what we intended by
the language ``allowable emission rate''--namely, that the NSPS would
be an ultimate cap on emissions for sources seeking above-formula stack
height credit. Our reading of the preamble language is reasonable; the
commenters' reading is strained.
(d) Comment: One commenter (MSCC letter, document #IV.A-19, comment
#82) claimed that EPA uses improper criteria for evaluating GEP stack
height credit in the SIP, that EPA may only consider 40 CFR 51.100 and
section 123 of the Act, that the preamble, guidance
[[Page 22211]]
documents, TSD for the stack height regulations, and memos are not
appropriate to consider unless the rule itself is unclear. The
commenter claimed the rule is clear. According to the commenter, EPA
seeks to use these documents as regulations, or in place of the
regulations, when such collateral writings are not subject to
rulemaking, notice, comment or appeal. The commenter asserted that if
the rule is so unclear, as alleged by EPA staff, to require so much
collateral explanation, it is or may be unconstitutionally vague and
void. Also, the commenter claimed that EPA's selection of interpretive
documents is incomplete. According to the commenter, EPA has not
included correspondence specific to this case, has omitted court
decisions on the current rule, EPA's own brief in defending the rule to
the court, or the collateral demonstrations provided by MSCC.
Response: We believe the heading in the TSD (document #III.B-1),
``Criteria for Evaluation,'' may be a bit misleading. We are evaluating
the SIP against the statutory and regulatory requirements. We are not
seeking to use other documents as regulations, but to help explain the
regulations. Regarding the central issue, whether it is appropriate to
consult documents other than the rule and statute, please see our
response to the previous comment.
The list of documents under ``Criteria for Evaluation'' on page 51
of the TSD is not exhaustive. We have cited to and included in our
record numerous other documents, and have considered the record as a
whole in reaching our final decision.
We do not believe the regulation is unconstitutionally vague; in
any event, this is a complaint about the regulation itself, which may
not be raised in this action.
(e) Comment: Two commenters (State letter, document #IV.A-23, p.
21; Goetz letter, document #IV.A-18, exhibit D, pp. 24-26) stated that
EPA's own Guideline for Determination of Good Engineering Practice
Stack Height makes clear that the GEP stack height credit is first
calculated and then this height is input into an air quality model to
set SIP emission limitations. They also assert that the Guideline makes
clear that the NSPS emission rate is used only for the fluid modeling
demonstration. According to these commenters, nowhere does the
Guideline even hint that the NSPS emission rate would constrain the
ultimate emission limit for sources seeking above-formula stack height
credit. The commenters argue that the State followed the process
outlined in EPA's Guideline in setting MSCC's SIP emission limit.
Response: The commenters are correct that the Guideline
contemplates a two-step process in which first, GEP stack height credit
is determined and second, an emission limitation is set. However, the
commenters gloss over a critical aspect of the Guideline. When the
Guideline discusses the process for setting emission limitations in
above-formula situations, the Guideline, at pages 58-59, cross-
references item G of Table 3.1 of the Guideline: \25\
---------------------------------------------------------------------------
\25\ We have discovered that there are two different versions of
the Guideline. The version submitted by MSCC as Exhibit 131 cross-
references item F of Table 3.1. We refer to the version we included
in our docket as document #II.A-12, which cross-references item G of
Table 3.1.
``Sources with a physical stack height greater than the GEP height
based on Equation 1, that wish to establish the correct emission
limit should input the GEP height (given by Equation 1, fluid model
or field study) into an air quality model to set the emission
---------------------------------------------------------------------------
limitations. Refer to Table 3.1, item G.''
Table 3.1, item G, at page 51 of the Guideline, describes the process
for establishing GEP stack height for stacks above formula height and
indicates that the resultant physical stack height should be used to
set emission limits. However, a footnote to this statement reads as
follows:
``Where some other meteorological condition is more controlling than
downwash, adjust the emission rate to avoid a violation of a NAAQS
or available PSD increment.''
Thus, under the Guideline it might be necessary to adjust the emission
limit downward from the NSPS or BART rate used in the fluid modeling or
field demonstration. By the same token, if some other more controlling
meteorological condition is not present, it is clear the Guideline
considers downwash to be controlling, and the emission limit must be
consistent with the NSPS or BART value used in the fluid modeling or
field demonstration.
Other language from the Guideline confirms this interpretation. At
page 52, the Guideline states:
``In conducting a demonstration, a source should use the modeled
stack height, input the applicable emission rate that is equivalent
to NSPS for that source category \1\, and add in the background air
quality as determined by procedures contained in two EPA guidance
documents (EPA, 1978, 1981).''
Footnote 1 to the above text reads as follows:
``However sources may on a case-by-case basis demonstrate that such
an emission is not feasible for their situations and determine their
emission limitations based on Best Available Retrofit Technology.''
(emphasis added)
It is apparent that we viewed the ``applicable emission rate'' used in
the fluid modeling or field study as an emission limitation, that might
have to be adjusted downward during dispersion modeling to address
meteorological conditions more controlling than downwash, but that
could not be adjusted upward. This reading is consistent with the
language of the regulation, preamble, and numerous other EPA documents
that we have cited in this rulemaking.
(f) Comment: Two commenters (Goetz letter, document #IV.A-18,
exhibit D, pp. 19-21; MSCC letter, document #IV.A-20, comment # 1.D)
stated that no one suggested that the NSPS would have to be the
applicable emission limit because the rule is clear that the NSPS
emission rate is for purposes of the demonstration only. The commenters
asserted that EPA's failure to notify the State or MSCC during late
1995 and the first few months of 1996 that the NSPS would have to be
used as an actual limit is evidence that the regulation does not
require that the NSPS be applied as an ultimate emission limit.
Response: Our meteorologist did not suggest that the NSPS would
have to be the applicable emission limit during the time period
mentioned for two reasons. First, at that time, the focus of the
various parties' efforts was not on final emission limits, but on the
design of the wind tunnel study. Second, our meteorologist was
initially not aware that the NSPS would have to be the applicable
emission limit. However, as explained in response to other comments, we
disagree with the commenter's assertion that the rule is clear that the
NSPS emission rate is for purposes of the demonstration only. On the
contrary, the rule requires that the NSPS be met as the applicable
emission limit. We also disagree that our not having notified MSCC
during late 1995 and the first few months of 1996 that the NSPS would
have to be used as an actual limit is evidence that the regulation does
not require that the NSPS be applied as an ultimate emission limit.
Instead, it is merely evidence that we were not focusing on ultimate
emission limits and had not yet addressed the requirement. Elsewhere in
this document, we have explained in detail why we think the regulation
requires that the NSPS apply as an ultimate cap on emission limits in
above-formula situations.
(g) Comment: One commenter (State letter, document #IV.A-23, p. 20)
stated that the fact that Congress intended
[[Page 22212]]
above-formula stack height credit be granted only in rare circumstances
does not support EPA's position or offer insight into the question at
issue. The commenter asserted that Congress' intent is too vague to
define the boundaries of EPA discretion. According to the commenter,
nothing in the CAA, the implementing regulations, or background to
section 123 supports the proposition that Congress intended to override
a state's authority to determine actual emission rates under section
110 of the CAA. The commenter argued that section 123 does not give EPA
authority to actually set an emission limit.
Response: In concluding that control first was an appropriate
regulatory approach in the above-formula context, the Court of Appeals
for the D.C. Circuit noted Congress' intent that above-formula stack
height credit be granted only in rare circumstances and with utmost
caution. NRDC v. Thomas, 838 F.2d 1224, 1241-1242, (D.C. Cir. 1988). We
believe that our interpretation of the stack height regulations is
consistent with Congressional intent and that this is another reason
our interpretation is entitled to deference. Our interpretation ensures
that sources will only receive above-formula stack height credit when
they are first willing to try to address downwash concerns by
installing NSPS or BART-level controls. Contrary to the commenter's
assertion, it is quite evident that section 123 restricts a state's
authority to set SIP emission limits. By upholding our use of control
first in the above-formula context, the D.C. Circuit further defined
the parameters that apply to establishing SIP emission limits. States
remain free to establish emission limits for sources, as long as they
are consistent with the requirements of section 123 and the stack
height regulations. In this case, the State would not have to cap
MSCC's stack emissions at the NSPS level if the State relied on the 65
meter de minimis stack height credit, instead of above-formula credit,
in setting MSCC's SIP limits.
(h) Comment: One commenter (MSCC letter, document #IV.A-20, comment
#8) stated that MSCC's stack height credit was granted with utmost
caution.
Response: The State may have granted the credit after considerable
analysis, but for the reasons stated in this document, we do not
believe the 97.5 meter stack height credit the State approved for
MSCC's 100-meter stack is valid under section 123 of the Act and our
stack height regulations.
(i) Comment: Two commenters (MSCC letter, document #IV.A-19,
comment #24; MSCC letter, document #IV.A-20, comment #2.Q; State
letter, document #IV.A-23, p. 20) disputed EPA's claim that the Court
in NRDC v. Thomas upheld the requirement to meet the NSPS as a
condition of above-formula stack height credit. The commenters claimed
the issue was not before the Court and was not addressed by the Court.
One of the commenters (MSCC) claimed that the court merely held that
EPA had the discretion under section 123 to impose the NSPS as a
presumption for above-formula stack height credit and never held that
EPA was actually applying the NSPS as a precondition for obtaining GEP
credit. Another commenter (State) cited an EPA Region 3 letter and an
EPA Headquarters letter and claimed EPA has made inconsistent
statements regarding the presence of a dispute regarding the NSPS
requirement; in this commenter's view, EPA's position would mean the
delegation of the court's decision making responsibilities to the
parties and their briefs.
Response: We addressed this issue in detail in the TSD for our
proposal, and we stand by that discussion. See TSD pages 64-66. The
Court in NRDC v. Thomas upheld the stack height regulations, and in
doing so, specifically held that EPA had the discretion to impose
control-first in the above-formula context. NRDC v. Thomas, 838 F.2d
1224, 1241. Using the NSPS as a mere modeling assumption is not the
same as ``control-first.'' Our preamble made clear that control-first
meant the imposition of controls as a prerequisite to stack height
credit. 50 FR 27896, July 8, 1985.
It is true that there was no dispute before the court regarding the
existence of the NSPS requirement (all parties understood that the NSPS
would have to be met as a prerequisite for above-formula stack height
credit). However, the propriety of this requirement was most certainly
argued before the court. See TSD pages 64-66. Despite the arguments of
the industry petitioners, the court upheld our regulations.
Regarding our reference to the briefs in the NRDC v. Thomas case,
it was the State in its opinion about the stack height regulations that
first cited the briefs as evidence of EPA's intent in the stack height
regulations. (See memorandum dated August 1, 1996 from Jim Madden to
Mark Simonich, attachment to document #II.C-9.) This led us to examine
some of those briefs in detail. We think the briefs reflect the nature
of the dispute before the court and the understanding of the parties
regarding the requirements of the stack height regulations at the time
the regulations were promulgated.
Regarding Region 3's 1988 letter (October 6, 1988 letter from
Marcia Mulkey to John Proctor, document #IV.C-65), the views expressed
by Region 3 counsel in 1988 support our position in almost every
respect. Ms. Mulkey completely rejected Mr. Proctor's assertion that
the NSPS was a mere modeling assumption. Among other things, Ms. Mulkey
concluded that Mr. Proctor's reading of the regulations would render
the above-formula stack height analysis artificial and unrelated to the
health and welfare criteria which the D.C. Circuit, in the Sierra Club
v. EPA case, had held must be used to define excessive concentrations
in the above-formula context.
Regarding the narrow portion of the letter that the commenter
focuses on, Ms. Mulkey was indicating that no party to the NRDC v.
Thomas case had raised the alternative interpretation that Mr. Proctor
was asserting (that the NSPS was a mere modeling assumption) and that
the Court's holding, approving EPA's stack height regulations, was in
no way dependent on this alternative interpretation. Thus, in Ms.
Mulkey's view, EPA remained free to interpret the stack height
regulations to require that NSPS or BART be met as an emission limit.
We agree with Ms. Mulkey's conclusion, as far as it goes. But, in
addition, the NRDC v. Thomas court specifically upheld the application
of control-first in the above-formula context, and, as we note above,
control-first is not a mere modeling assumption.
The April 20, 1989 Headquarters letter from Gerald Emison to John
Proctor (document #II.A-7) that the commenter cites indicated that
Headquarters fully endorsed Region III's conclusions and supporting
rationale in Ms. Mulkey's October 6, 1988 letter, but also cited from
the NRDC v. Thomas opinion, and stated, ``We believe that the opinion
indicates clearly that the court regarded the presumptive NSPS emission
limit as a limit that must be complied with once the fluid modeling was
completed * * *'' The Emison letter cited to language in the opinion
dealing with industry concerns that the NSPS would not be attainable,
language that indicated the court understood the NSPS would be a cap on
ultimate emissions. (``* * * industry petitioners assert that in order
to use the NSPS presumption, EPA must be able to point to substantial
evidence that it is attainable by most of the affected sources. But as
EPA allows any source to use a higher emissions rate when NSPS is
infeasible, there is no need for any sort of generic demonstration that
it is normally so.'' NRDC v. Thomas, at 1242.) We note that the court
did not
[[Page 22213]]
respond to the industry concerns by saying the NSPS was a mere modeling
assumption, and that a higher SIP limit might result from dispersion
modeling.
Ultimately, the central question is whether we are reading the
stack height regulations reasonably. Either we are reasonable in
reading the regulations to require a source to meet the NSPS or BART as
a prerequisite for above-formula stack height credit or we are not. If
our longstanding interpretation is reasonable, we believe it is too
late for anyone to challenge the requirement because the NRDC v. Thomas
court already upheld the stack height regulations. And, all the
arguments about lack of notice and inappropriateness of applying NSPS
to sources not otherwise subject to the NSPS are irrelevant; they
should have been advanced at the time EPA adopted the regulations and
first asserted its interpretation, or not at all.
(j) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 23) stated that EPA relied on the availability of approvable
feasibility studies as a justification for not having any evidence in
the record regarding the validity of the NSPS presumption. The
commenter asserted that since such studies are not possible, EPA's and
the court's reliance on such studies to approve the NSPS presumption is
flawed.
Response: This comment goes to the validity of the 1985 stack
height regulations themselves and is not relevant to our action on the
SIP before us. In any event, the commenter's conclusion that such
studies are not possible is not supported. The fact that one State has
not been able to gain EPA approval for an infeasibility analysis for
one source does not mean that such studies are not possible. Studies
may be ``doggedly pursued;'' that does not mean they reflect sound
analysis.
(k) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 32; MSCC letter, document # IV.A-20, comment #'s 2.P and
second 5.E) stated that it is unfair and unlawful to apply the NSPS to
MSCC, because MSCC is not a new source, and because the law does not
require meeting the NSPS as a precondition of obtaining above-formula
stack height credit. Another commenter (CPP letter, document # IV.A-18,
exhibit A, p. 5) also asserted that MSCC is not a new source and the
NSPS should not apply.
Response: We addressed this issue in the TSD to our proposal, and
we stand by that discussion. See TSD pages 58-60. Also, please see our
responses to previous comments.
(l) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 33) stated that there is no source category clearly
applicable to sulfur recovery plants built prior to 1976 and that there
is no source category applicable to existing sulfur recovery plants
built before 1976 and 1970 that are not located within the bounds of a
petroleum refinery or under the control of a petroleum refinery.
Response: First, MSCC agreed to the use of the NSPS applicable to
sulfur recovery plants for purposes of its fluid modeling
demonstration. It is not convincing for the commenter to now complain
that MSCC's sulfur recovery plant is not within the source category to
which the NSPS applies. Second, the commenter misinterprets the NSPS.
The regulation specifically provides that ``the Claus sulfur recovery
plant need not be physically located within the boundaries of a
petroleum refinery to be an affected facility provided it processes
gases produced within a petroleum refinery.'' 40 CFR 60.100(a).
Clearly, MSCC's sulfur recovery plant falls within this description.
See also 41 FR 43866, October 4, 1976. In promulgating 40 CFR
51.100(kk)(1), we recognized that some sources would be grandfathered
and not strictly subject to the NSPS; however, we believed it was
appropriate to use the NSPS for the source category to which the source
belonged, even if the individual source was not subject to the NSPS
under part 60. Thus, we believe it is appropriate to use the 40 CFR
part 60, subpart J standards when evaluating the emission limits for
MSCC in an above-formula scenario.
(m) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 33, 58, 96) stated that no source reading EPA's proposed or
final stack height regulations would have had notice that the agency
would impose NSPS as an operating limit on it as a condition of
receiving GEP stack height credit. The commenter objected to EPA's
reasoning in the proposal that MSCC's problems with the stack height
rule should have been appealed when the rule was published. The
commenter claimed that a reasonable person reading the rule text could
not have foreseen the meaning that EPA now assigns to the rule. The
commenter asserted that EPA has modified many aspects of the stack
height regulations by reference to and interpretation of internal
guidance and memos, and court briefs and decisions.
Response: To the extent this is a claim that EPA provided
inadequate notice of the NSPS and other requirements in the 1985 stack
height regulations, we believe this claim could only be raised in a
challenge to the stack height regulations themselves, and is not
relevant to this rulemaking action. See TSD pages 60-61. In any event,
we disagree with the commenter's assertion that no source would have
had notice that the agency would impose NSPS as an operating limit in
above-formula situations. Our final stack height rulemaking notice and
materials in the rulemaking record made clear that the NSPS or
alternative limit used in above-formula fluid modeling determinations
would have to be met as a condition of obtaining above-formula credit.
See 50 FR 27898, 27905, July 8, 1985; documents cited at page 54 of our
TSD. As we pointed out in the TSD to our proposal, other persons
reading the final rule understood this and registered their objections
with EPA and the NRDC v. Thomas court. See TSD at pages 60-61, 64-65.
See also memorandum dated June 19, 1985 from Eric Ginsburg to Files
entitled, ``Conference Call With OMB to Discuss Concerns about the
Stack Height Regulations,'' document # II.A-13; letter dated June 21,
1985 from R. E. Boyle, President, Ormet Corporation, to Lee Thomas,
Administrator, EPA, regarding ``Section 123 Stack Height Regulations,''
document # IV.C-63; letter dated June 17, 1985 from W. S. White, Jr.,
Chairman of the Board, American Electric Power Company, Inc., to Lee
Thomas, regarding ``EPA Stack Height Regulations--Ohio Power Company's
Kammer Plant,'' document # IV.C-62; letter dated June 20, 1985 from
Henry V. Nickel, Hunton & Williams, to Lee Thomas, regarding ``'Red
border'' draft stack height rules,'' document # IV.C-61; letter dated
June 21, 1985 from Congressman Allan B. Mollohan to Lee Thomas,
document # IV.C-60; letter dated June 20, 1985 from R. E. Disbrow,
President, American Electric Power Company, Inc., to The Honorable
Robert C. Byrd, regarding ``EPA Stack Height Regulations--Ohio Power
Company's Kammer Plant Marshall County, West Virginia,'' document #
IV.C-59; letter dated June 27, 1985 from Richard F. Celeste, Governor,
Ohio, to Lee Thomas, regarding ``EPA Stack Height Regulations--Ohio
Power Company's Kammer Plant,'' document # IV.C-58.
We also disagree with the commenter's assertion that we have
modified the stack height regulations without rulemaking or somehow
ignored the rule's plain language. As to the specific interpretation
issues raised by the commenter, we discuss these in detail in responses
to other comments. As a general proposition, we believe we
[[Page 22214]]
have appropriately consulted the statute, the preamble to the stack
height regulations, relevant case law, and other documents to help
interpret portions of the regulations that may be ambiguous or complex.
(n) Comment: Several commenters (MSCC letter, document # IV.A-19,
comment # 88; State letter, document # IV.A-23, pp. 17, 18; Goetz
letter, document # IV.A-18, exhibit D, pp. 19, 22) asserted that
contrary to EPA's statements, EPA has not consistently read the
language of the rule to require that a source meet the NSPS as a
condition of obtaining above-formula stack height credit. According to
these commenters, EPA did not alert the state or MSCC to such reading
before MSCC performed fluid modeling or during the Montana contested
case proceeding; this, in spite of the fact that the record is clear
that DEQ modeler/meteorologist John Coefield was in continual contact
with EPA's meteorologist on these issues. The commenters asserted that
EPA's meteorologist was not aware of this interpretation until after
the State approved MSCC's demonstration. The commenters claimed that in
fact, EPA's input during the process indicated that the State was using
the correct approach in determining GEP formula height and the
resulting SIP emission limit.
Response: The commenters are correct that the Region's
meteorologist was unaware of this requirement until after he spoke to
staff from another Region. However, upon learning of this, we informed
the State. This was in May of 1996, before the State adopted emission
limits for MSCC. We had several discussions of this issue with the
State after our initial call in May 1996. See Record of Adoption,
transcript of August 8, 1996 Board Hearing, testimony of Mark Simonich,
pp. 24-28, document # II.C-3. We faxed a letter to the State describing
our position on this issue on July 18, 1996, before MSCC or Montana
signed the MSCC stipulation. See document # II.C-5. MSCC signed the
stipulation on July 22, 1996 and the MDEQ did not sign the stipulation
until after that. See document # IV.A-17, MSCC Exhibit 132, letter from
Mark Simonich to Mary Westwood dated August 2, 1996, with August 1,
1996 memorandum from Mark Simonich to Montana Board of Environmental
Review attached.
Although our meteorologist consulted with the DEQ modeler/
meteorologist regarding the conduct of the fluid modeling
demonstration, it is an exaggeration to say he was in continual contact
with the DEQ modeler/meteorologist. It is important to note that we
were not a party to the contested case hearing, and that our
meteorologist was providing input from home regarding the modeling at a
time in late 1995 when EPA was shut down as a result of the budget
standoff between President Clinton and Congress. Thus, in providing his
input, our meteorologist often did not have access to the advice of
legal counsel and EPA Headquarters personnel. Our meteorologist was
providing his best advice to the DEQ modeler/meteorologist under
difficult circumstances.
In addition, the focus of MSCC's contractor's efforts in late 1995
and early 1996 was the design of a wind tunnel study, not final SIP
emission limits. Consequently, our meteorologist's focus, and the focus
of his discussions with the DEQ modeler/meteorologist, was the design
and execution of the wind tunnel study, not final SIP emission limits.
See memorandum of Kevin Golden, document # IV.C-71. This is reflected
in the January 31, 1996 and March 15, 1996 letters from Richard Long to
Jeff Chaffee cited by one of the commenters (document #'s II.F-19 and
20). These letters focused on our concerns with the manner in which
MSCC's contractor had performed fluid modeling, not on ultimate
emission limits. It is also important to remember that MSCC did not
start out seeking above-formula stack height credit, but only agreed to
conduct above-formula modeling relatively late in the process. Even
then, and despite our and the State's warnings that within-formula
demonstrations would not be accepted, MSCC continued to pursue within-
formula modeling demonstrations. This was an evolving process, and
statements we may have made regarding relying on GEP stack height
credit generally to set SIP limits--for example, based on de minimis or
formula stack height credit--have no bearing on the matter before us.
Ultimately, whether we alerted MSCC or the State before MSCC's
contractors began their wind tunnel study for above-formula stack
height credit that NSPS or BART would have to be met in fact, is
irrelevant to the real issue: what the statute and our regulations
require. It also does not change the fact that EPA as a regulatory
agency has since the inception of the stack height regulations read the
regulations to require that the NSPS be met as an ongoing limit as a
condition of obtaining above-formula stack height credit. The fact that
we did not also reiterate our longstanding interpretation before the
conduct of the wind tunnel study does not form a basis for us to ignore
the requirements of our regulations in evaluating the SIP.
Furthermore, we believe the State has an independent obligation to
evaluate applicable regulatory requirements. As the State admits, this
was not the first time this issue had arisen in the State. (State
comment, document # IV.A-23, page 18, footnote 18.) As noted in our
TSD, we informed the State of our reading of the stack height
regulations in 1991, while commenting on an earlier SIP effort for the
East Helena area. We believe it would have been prudent and appropriate
for the State to review information in its files relative to that stack
height analysis, and to pass on relevant information to MSCC.
(o) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, pp. 19, 20) stated that in written comments on the State's
protocol for conducting the fluid modeling demonstration, EPA did not
indicate that the NSPS would be the applicable emission limit; nor did
EPA express incredulity that MSCC would spend money on such a study
when the result would be a significantly lower emission limit than MSCC
would be subject to without conducting a study.
Response: The commenter is correct that Mr. Long's January 31, 1996
letter to the State (document # II.F-19) did not speak to the issue of
the NSPS as the applicable emission limit. As we note above, the scope
of this letter was limited to the conduct of the fluid modeling
demonstration, and thus, it is not surprising that it did not address
ultimate SIP emission limits. At that point in time, EPA personnel were
not focusing on ultimate emission limits and had not specifically
considered or researched the rule's requirements regarding ultimate
emission limits for sources seeking above-formula stack height credit.
We have acknowledged that our meteorologist, whose expertise is
modeling and meteorology, was not initially aware that the rule
requires that the NSPS be met as an ultimate limit in above-formula
circumstances. If he had been, he may have questioned MSCC's course of
action. However, none of this changes the requirements of the
regulations, and we believe we have a duty to disapprove the SIP
because MSCC's limits are not consistent with the stack height
regulations.
(p) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, pp. 26-27) stated that EPA Region VIII plainly misled both
DEQ and MSCC on the NSPS limit issue and they have scrambled, since the
summer of 1996, to shore up their position by dredging up whatever
documentation they can find to support a claimed ``long-standing''
interpretation of the rule. The commenter complained that as of July
[[Page 22215]]
1996, EPA had only provided two documents to the State on EPA's NSPS
limit position. The commenter asserted that all the other documents now
cited by EPA were not provided to the State or MSCC on a timely basis,
and EPA's position was not made known at a time when it would have been
useful in the SIP process.
Response: We certainly did not intend to mislead the State and MSCC
in any way. It is clear from the record that we informed the State that
it was mis-applying the stack height regulations before the State
adopted SIP limits for MSCC. The State, with MSCC's concurrence, made a
conscious decision to ignore our input.
We believe the commenter mis-portrays our communications with the
State on this matter between May and July 1996. As noted in the July
16, 1996 letter from Jim Madden to James Goetz that commenter cites
(document # IV.A-18, MSCC Exhibit 156), EPA had provided detailed
citations to relevant preamble language. This is the same preamble
language we rely on now. As to the number of documents we provided to
the State as of July 1996, or subsequently, we think this is irrelevant
to our action in this matter. The fundamental issue is whether the SIP
meets the requirements of the CAA and our regulations. It is our
judgment that MSCC's emission limits, based on stack height credit of
97.5 meters, do not meet these requirements for the reasons stated in
our proposal and elsewhere throughout this document. The State has had
plenty of time to correct the problems with the SIP since we first
informed them of the problems with MSCC's stack height credit, but has
chosen not to do so.
(q) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, p. 26) stated that many of the documents in support of EPA's
claimed long-standing interpretation of the NSPS emission rate issue
are less than clear regarding the specific issue in question and the
weight to be accorded these sources is questionable. The commenter
noted that one of the documents is a letter to a particular law firm
not involved in the present issue.
Response: We believe the documents cited are clear and indicate
that we have held the NSPS emission limit position since the inception
of the stack height regulations, and have continued to follow it
subsequently. The letter to the law firm that the commenter demeans was
an April 20, 1989 letter from Gerald A. Emison, an EPA Headquarters
official at the time, to John Proctor, who represented Pennsylvania
Electric Company (see document # II.A-7). That letter addressed the
very same issue that we are dealing with in this matter--whether the
NSPS must be met as an emission limit by sources seeking above-formula
stack height credit.
(r) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 88) stated that EPA points to the use of the term ``allowable
emission rate'' in the regulation, but notes that the regulation does
not use the term ``enforceable emission rate'' or ``emission
limitation,'' even though these are terms within EPA's ``lexicon.''
Response: The commenter is correct that we did not use these
alternative terms in the regulation. We do not believe this changes the
meaning of ``allowable emission rate.'' The Clean Air Act itself
defines ``emission limitation'' to include ``a requirement established
by the State or the Administrator which limits the [* * *]
rate [* * *]
of emissions of air pollutants on a continuous basis[.]'' (See section
302(k) of the Act.)
(s) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 88; MSCC letter, document # IV.A-20, comment # 2.P) stated
that fluid modeling was available to ExxonMobil, without NSPS applying,
and Conoco received GEP stack height credit above 65 meters without
having to conduct fluid modeling. The commenter claimed that NSPS is
not applied to any other source in this airshed by this SIP revision,
but instead it is only applied to new sources as intended. The
commenter stated that MSCC's treatment is inequitable, unreasonable,
and inconsistent with the statute and rule.
Response: The NSPS did not apply to ExxonMobil's FCC CO-boiler
stack because ExxonMobil performed fluid modeling to obtain credit for
a within-formula stack height credit and not above-formula stack height
credit. Likewise, the NSPS did not apply to Conoco because Conoco was
not seeking above-formula stack height credit. Conoco received approval
of their GEP formula height stack on June 7, 1989 (54 FR 24334). The
actual stack height is 82.3 meters and the formula height is 75.7
meters. In the Billings/Laurel SO2 SIP, the MDEQ initially modeled
Conoco's stack at the 82.3 meters. However, in a letter to the MDEQ
dated December 15, 1994, we indicated that the State needed to justify
using the higher stack height (see document # IV.C-17). On April 14,
1995, the State sent a letter to the Billings SO2 Parties indicating
that there was a revision in the Dispersion Modeling Scenario (see
document # IV.C-39). Among other things, the letter indicates that the
new compliance demonstration will use the 75.7 meters stack height
credit for Conoco. Subsequent modeling done by the State has used the
75.7 meters stack height credit at Conoco. MSCC may avoid application
of the NSPS in this SIP by accepting GEP stack height credit of 65
meters. MSCC will only be subject to an NSPS limit if it insists on
above-formula stack height credit. This result follows from our stack
height regulations, and we do not believe it is inequitable.
(t) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 41) indicated that MSCC has been treated inequitably compared
to ExxonMobil, that ExxonMobil was allowed to make a fluid modeling
demonstration to demonstrate within formula GEP height, that formula
height was calculated based on a rounded nearby structure that is
taller than it is wide, but that GEP credit was really based on the
Billings Generation Inc. (BGI) structure that creates downwash at
MSCC.\26\ According to the commenter, this BGI structure is further
from ExxonMobil than it is from MSCC. The commenter asserted that
because ExxonMobil was able to conduct a within formula determination,
it is not being required to meet an NSPS limit like MSCC, and this is
unfair. Another commenter (CPP letter, document # IV.A-18, exhibit A,
p. 7 and Attachment I) made essentially the same comment.
---------------------------------------------------------------------------
\26\ BGI is now the Yellowstone Energy Limited Partnership
(YELP).
---------------------------------------------------------------------------
Response: We do not believe MSCC has been treated inequitably or
unfairly. ExxonMobil properly calculated a formula height of 76.7
meters and then demonstrated the validity of that formula height
through a fluid modeling demonstration. For ExxonMobil, the formula
height of 76.7 meters was calculated considering four solid components
imbedded in a lattice framework. The four imbedded components are the
elevator (3.2 m by 5 m by 49.2 m), the regenerator (7.6 m in diameter
and 30 m high), the reactor (6.1 m in diameter and 53.4 m high) and the
fractionator (3.2 m in diameter and 45.3 m high). The calculated stack
height was based on the four structures, which are within 5L of the
stack in question, and not the lattice framework, and was determined by
using our Building Profile Input Program (BPIP) software. (See document
# II.F-2.)
The formula used to determine the formula stack height is Hg = H +
1.5 L, where Hg is the good engineering practice stack height measured
from the ground elevation at the base of the stack, H is the height of
nearby structure(s)
[[Page 22216]]
measured from the ground-level elevation at the base of the stack, and
L is the lesser dimension, height or projected width, of nearby
structures. In the BPIP modeling for ExxonMobil, H was determined to be
45.29 m and L was determined to be 20.95 m. In other words, the
structures together were taller than they were wide, but their
projected width was significantly greater than MSCC's stack support
structure and their height was significantly less. These structures
were not a stack or TV or radio transmission tower, which our GEP
Guideline states should not be considered in GEP stack height
determinations. ``Guideline for Determination of Good Engineering
Practice Stack Height (Technical Support Document for the Stack Height
Regulations (Revised),'' June 1985, EPA-450/4-80-023R, at p. 7
(document # II.A-12). In addition, these structures were not part of
the stack for which formula height was being determined. MSCC's
situation is different--the stack support structure cannot be used to
calculate formula height.
In ExxonMobil's case, we believe formula height was properly
calculated, and because ExxonMobil was only seeking stack height credit
equivalent to formula height, ExxonMobil was permitted to make a fluid
modeling demonstration under 40 CFR 51.100(kk)(2) rather than
subsection (kk)(1). Under subsection (kk)(2), a source is only required
to use its SIP limit (or if there is none, its actual emissions rate)
in fluid modeling, and is not required to meet an NSPS limit as is the
case for sources seeking above-formula stack height credit under
subsection (kk)(1). Because MSCC was seeking above-formula stack height
credit, subsection (kk)(1) applied.
In addition, in a fluid modeling demonstration, our rules allow
consideration of structures up to one-half mile from the stack, even if
one-half mile is not nearby for purposes of calculating formula height.
40 CFR 51.100(jj)(2). Thus, it is irrelevant that the formula height
calculation for ExxonMobil was not based on the BGI structure, but that
the fluid modeling modeled the BGI structure.
In our view, any differences in treatment of ExxonMobil and MSCC
result from the proper application of our stack height regulations.
Under our regulations, there is no question that physical layout plays
a role in formula and GEP determinations. The layout of the ExxonMobil
facility allowed ExxonMobil to calculate formula height based on the
four structures contained within the lattice; these structures were
within 5L of the stack. At MSCC, there were no structures within 5L of
the stack on which MSCC could calculate formula height greater than 65
meters. This difference, which seems inequitable to the commenters, is
inherent in the rule. We understand that downwash effects present at
4.9L do not magically disappear at 5L, but this is the line EPA drew in
the stack height regulations, and the regulations were upheld by United
States Court of Appeals for the D.C. Circuit. To the extent the comment
goes to the validity of the stack height regulations, we do not believe
the comment is timely or relevant to this rulemaking.
(u) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 24) stated that two existing sources in Billings erecting
stacks after 1977 were granted credit for stacks without a precondition
that NSPS controls be installed. According to the commenter, both
credits were based on tall thin structures, albeit not as tall and thin
as MSCC's structure.
Response: The commenter has not provided sufficient information for
us to completely respond to the comment. If the commenter is referring
to ExxonMobil and Conoco, see our responses to the above comments. If
the commenter is referring to Cenex, we note that Cenex was required to
raise some stacks as a result of the 1977 Stipulation. However, none of
Cenex's stacks are above 65 meters and the NSPS ``precondition'' would
not apply. In fact, except for MSCC, the only other sources in the
Billings/Laurel SIP where the stack height credit in the modeling is
greater than 65 meters are Conoco's boiler stack at 75.7 meters (see
discussion above), ExxonMobil's FCC CO-boiler stack at 76.7 meters (see
discussion above), and Montana Power's stack at 106.7 meters. Montana
Power's GEP stack height credit was approved on June 6, 1989 (54 FR
24334). The June 6, 1989 Federal Register notice indicates that Montana
Power's stack height credit was grandfathered. None of these stacks are
subject to the NSPS precondition requirement.
(v) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 89) asked why any existing source already automatically
eligible for a more lenient-than-NSPS short term and annual limitation
at 65 meters would accept an NSPS limit on its pre-NSPS facility as a
pre-condition of receiving credit for GEP above 65 meters. In a similar
vein, another commenter (Goetz letter, document # IV.A-18, exhibit D,
p. 25) stated that it would not make sense for a source to expend the
resources of a fluid modeling demonstration to justify above-formula
stack height credit if the source must meet the NSPS as an operating
limit. These commenters claimed that under EPA's reading, the rule has
no utility. According to these commenters, although EPA argues that
conditions other than downwash may be controlling in dispersion
modeling to set emission limitations, EPA's argument is sophistry. The
commenters asserted that EPA has pointed to no real-world example of
where this rule has proved useful in such a situation. One of the
commenters asked EPA to provide documentation of specific cases where
the above-formula stack height rule has been used in a case that fits
this category. In addition, the commenter claimed that documents EPA
cited in its proposal and TSD do not support the proposition that
conditions other than downwash may be more controlling in some cases.
Response: First, we would not expect an existing source with an
emission limit more lenient than the NSPS at a 65 meter stack height
credit to seek above-formula stack height credit. In fact, we
explicitly recognized this in the preamble to the stack height
regulations:
In the event that a source believes that downwash will continue
to result in excessive concentrations when the source emission rate
is consistent with NSPS requirements, additional stack height credit
may be justified through fluid modeling at that emission rate.
A source, of course, always remains free to accept the emission
rate that is associated with a formula height stack rather than
relying on a demonstration under the conditions described here.'' 50
FR 27898, July 8, 1985.
By the same token, sources have no absolute entitlement to above-
formula stack height credit. As stated before, the premise behind the
above-formula provisions of the stack height regulations was that
above-formula stack height credit would be granted rarely and with
utmost caution. The D.C. Circuit recognized this as legitimate, and the
NSPS requirement, as interpreted by EPA, effects this goal. The
commenter believes MSCC has somehow been wronged because we have not
interpreted our regulations to make it easier for MSCC to obtain above-
formula stack height credit.
Second, we believe there are conditions under which a source would
want to seek above-formula stack height credit even though it would
have to meet the NSPS as an operating limit. As noted by the commenter,
we mentioned one such possibility in our proposal--where conditions
other than downwash may be controlling in dispersion modeling. Another
example may be when a source would have to meet an
[[Page 22217]]
emission limit lower than the NSPS using within-formula stack height
credit. Although we have not researched whether this situation has
actually arisen ``in the real world,'' we think the commenter's concern
on this point is irrelevant. The stack height regulations were not
intended to encourage sources to seek above-formula stack height credit
or to make it easy for them to obtain such credit. 50 FR 27898, July 8,
1985.
In addition, the commenter ignores the possibility that a source
could demonstrate the infeasibility of meeting the NSPS limit and
justify a higher, alternative limit. See 40 CFR 51.100(kk)(1). Again, a
source might want to do this if it would have to reduce emissions below
this alternative limit based on within-formula stack height credit.
Regarding the documents cited in our proposal for the proposition
that conditions other than downwash may be more controlling, we have
discovered that there are two different versions of the Guideline for
Determination of Good Engineering Practice Stack Height. In the version
we included in our rulemaking docket, the relevant item in Table 3.1 is
Item G. In the version submitted by the commenter, the relevant item in
Table 3.1 is Item F. In either case, Footnote 3 to the relevant Item
states, ``Where some other meteorological condition is more controlling
than downwash, adjust the emission rate to avoid a violation of a NAAQS
or available PSD increment.'' We note that the commenter cites to Item
F on the prior page of his comments.
Language from the discussion of above-formula stack height credit
in the preamble to the stack height regulations also touches on the
possibility that conditions other than downwash may be controlling:
An additional theoretical complication is presented when an
absolute concentration is used where meteorological conditions other
than downwash result in the highest predicted ground-level
concentrations in the ambient air. In such cases, a source that has
established GEP at particular height, assuming a given emission
rate, may predict a NAAQS violation at that stack height and
emission rate under some other condition, e.g., atmospheric
stability Class ``A'.'' 50 FR 27899, col. 1.
(w) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, p. 19) stated that it is obvious that MSCC would not have
undergone the considerable expense of more wind tunnel modeling if it
had known the NSPS would be imposed as an actual emission limit because
the NSPS standard was a mere fraction of the emission limit already
proposed by DEQ for a 65 meter de minimis stack.
Response: Although MSCC may well have chosen not to conduct
additional wind tunnel modeling, it is also possible MSCC may have
pursued additional wind tunnel modeling because, even if we had at that
point informed MSCC that the NSPS would be the applicable emission
limit, MSCC may have chosen to ignore, or, as MSCC has in fact chosen
to do, contest our position. As we have noted elsewhere in this
document, MSCC proceeded with other stack height theories even after
MSCC was aware that we would reject those theories. In any event, this
comment is not relevant to the central issue, which is whether the
stack height regulations require that the NSPS or BART emission rate
serve as a cap on SIP limits in above-formula situations.
(x) Comment: One commenter (MSCC letter, document # IV.A-19, p. 3;
MSCC letter, document # IV.A-20, comment # 1.M) stated that MSCC could
not feasibly install controls to achieve an NSPS level of control, and
cites to an expert's opinion regarding the subject.
Response: We are not forcing MSCC to seek above-formula stack
height credit. The requirement to at least meet the NSPS is a byproduct
of MSCC's decision to seek above-formula stack height credit. If MSCC
accepted the regulatory 65 meter credit, it could have emissions limits
significantly less stringent than the NSPS.
In addition, our regulations provide an opportunity for the State/
source to make a showing that the source cannot achieve an NSPS level
of control. We offered the State and MSCC the opportunity to
demonstrate infeasibility, but MSCC did not do so (see document #'s
II.C-12 and IV.C-40). MSCC seemed unwilling to make the attempt without
some assurance that the attempt would be successful (see document #
IV.C-41 and document # IV.A-17, MSCC Exhibit 19). The State did not set
an alternative BART limit based on an infeasibility showing by MSCC,
and therefore, this issue is not properly before us in this action. The
commenter's mere assertion of infeasibility does not provide a basis
for us to disregard the requirements of the stack height regulations.
We note that MSCC installed a SuperClaus unit in late 1998 despite its
claims that it was not ``economically practical or feasible'' to do so
(see document # IV.C-42 and document # IV.A-17, MSCC Exhibit 126,
Direct Testimony of Larry Zink, ``In the Matter of the Application of
the DEQ for Revision of the Montana State Air Quality Control of SO2
Emissions in the Billings/Laurel Area * * *'', December 5, 1995, pp.
27, 36.)
(y) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 98) stated that EPA uses the term ``alternative rate''
interchangeably with ``allowable emissions rate,'' and the commenter
implied that this somehow undercuts EPA's reading of ``allowable
emissions rate'' as meaning a rate that a source would have to meet and
not just assume for purposes of a fluid modeling demonstration.
Response: The regulation says the allowable emissions rate shall be
the NSPS unless a source demonstrates that the NSPS is infeasible, in
which case an alternative emission rate shall be established. Both
phrases, at root, use the term ``emission rate.'' We believe it is
reasonable to read this to mean that such alternative emission rate
would become the allowable emissions rate for purposes of the preceding
sentence in the regulation.
(z) Comment: One commenter stated (MSCC letter, document # IV.A-19,
comment # 100; MSCC letter, document # IV.A-20, 2nd comment #'s 5.A, B,
C, D, F, and G) that MSCC is a well-controlled source, citing to the
SO2 reductions MSCC has achieved for many years in the area.
Response: We are aware that MSCC removes sulfur compounds from
ExxonMobil's effluent stream. However, to the extent the commenter is
referring to ``well-controlled'' as a term of art in the preamble to
our stack height regulation, this term refers to an NSPS limit or a
BART alternative limit. To date, neither the State nor MSCC has been
willing to adopt the NSPS as a limit for MSCC. If the commenter is
using the term more generally, it is not relevant to our review of the
SIP. Our obligation under the CAA is to ensure that the requirements of
the CAA and our regulations are met. MSCC may or may not be ``well-
controlled'' in the generic sense, but MSCC's main stack limits have
not been set in accordance with our stack height regulations, and
certain other aspects of the SIP, which pertain to MSCC and other
sources, are deficient under the CAA and our regulations. It is
entirely possible the State could fix the SIP problems without imposing
additional emission reductions on MSCC. For purposes of a SIP, the
State chooses how to allocate the emissions reduction burden among
sources, not EPA. We review the State's choices to ensure that the SIP
meets the requirements of the CAA.
(aa) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 94) stated that the stack height regulations impose less
stringent
[[Page 22218]]
requirements for PSD sources attempting to justify above-formula stack
height credit through fluid modeling than they impose on existing
sources doing so. In the commenter's view, this seems odd since PSD
sources are increasing emissions in an area. The commenter found it
difficult to understand this apparent contradiction, particularly since
EPA appears to believe reducing emissions is the principal and
overriding purpose of section 123 of the CAA. The commenter appeared to
suggest that the NSPS rate prescription in 40 CFR 51.100(kk)(1) only
applies to PSD sources. The commenter thought it is unlikely that NSPS
forms an upper bound for PSD sources, but instead is an acceptable rate
for a fluid modeling demonstration, regardless of more stringent
requirements applicable to the source. The commenter wondered whether
MSCC is subject to the PSD program.
Response: First, the commenter mischaracterizes our interpretation
of section 123 of the CAA. The principal purpose of section 123 is to
prevent sources from using excessive stack height as a means to meet
the NAAQS. In any given SIP, sources may be able to justify higher
stack height credit and thereby increase emissions or keep emissions
the same. This is highly situation-dependent. Clearly Congress did not
want to allow use of stack height greater than GEP at the expense of
emissions controls.
Second, although the commenter may find this distinction odd, it
does not change the regulatory requirements that apply to non-PSD
sources. The commenter's recourse if it wished to challenge the
distinction between non-PSD and PSD sources was to seek review of the
original regulations within 60 days of promulgation. It may not
challenge the regulations now.
Third, PSD sources that are being considered in SIP development are
likely to be existing sources that happen to be subject to a PSD
permit, not necessarily a new or modified source adding emissions to an
area. Also, stringent modeling requirements apply to new or modified
PSD sources to ensure that they do not interfere with attainment or
maintenance of the NAAQS.
The practical implications of the distinction between non-PSD and
PSD sources are probably insignificant because PSD sources are
necessarily meeting Best Available Control Technology (BACT) limits
that, by definition, are at least as stringent as the NSPS. See 40 CFR
51.166(b)(12). Thus, although the fluid modeling requirements for PSD
sources appear to be less stringent, the control requirements
applicable to PSD sources are generally more stringent than those that
apply to non-PSD sources, and such sources have already undergone
stringent modeling requirements to receive their permits.
Regarding EPA's selection of the NSPS for above-formula
demonstrations and the fact that this does not really comprise an upper
bound for PSD sources, EPA selected a single level for all sources
seeking above-formula stack height credit. PSD sources are already
well-controlled; there was no need to establish some lesser cap on
emissions.
To our knowledge, MSCC does not have a PSD permit, and thus, is not
currently a PSD source. Additionally, our action on the SIP is not
meant to imply any sort of applicability determination under the PSD
program (Title I, part C of the Act) with respect to MSCC.
(bb) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, p. 23) stated that MSCC adopts and incorporates as part of
its comments the analysis contained in a memo by DEQ attorney Jim
Madden to Mark Simonich dated August 1, 1999 (sic, should be 1996)
(attachment to document # II.C-9).
Response: We have thoroughly analyzed and responded to the analysis
contained in Mr. Madden's memo in our TSD, at pages 58-67, and in this
document.
2. Issues Related to Best Available Retrofit Technology (BART)
We received a number of comments regarding an alternative BART
limit for above-formula stack height demonstrations. Although we
discussed with the State and MSCC the provision of our regulations that
allows sources the opportunity to show that an NSPS limit is infeasible
and then to develop an alternative BART limit, MSCC did not attempt to
make the requisite showings. Consequently, the State did not approve an
alternative BART limit for MSCC, and no alternative BART limit has been
submitted to us for approval. Therefore, we believe the majority of
comments regarding an alternative BART limit are irrelevant to our
action. Nevertheless, we are responding to the comments regarding BART.
Nothing in the comments has caused us to change our position regarding
disapproval of MSCC's stack height credit.
(a) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 22, 99, 103; MSCC letter, document # IV.A-20, comment # 1.I)
stated that EPA's arguments regarding BART and feasibility studies are
spurious and hypocritical. The commenter suggested that EPA has
inadequately defined BART and that therefore the opportunity to
demonstrate the infeasibility of meeting the NSPS limit and establish
an alternative BART limit amounts to impermissibly vague regulation.
The commenter asserted that no successful BART or feasibility analysis
has ever been done regarding implementation of stack height rules. The
commenter alluded to a BART analysis for another source that EPA
rejected. The commenter complained that the BART guidelines are
guidance and not regulations and that they are not authorized under
section 123 of the Act.
Response: Since the State did not adopt an alternative limit for
MSCC, based on an infeasibility showing, the commenter's arguments
regarding BART and our application of the regulations are irrelevant to
our action on the SIP before us. In addition, to the extent the
commenter is objecting to an alleged flaw in the stack height
regulations, the objection could only be raised in a challenge to the
stack height regulations and is irrelevant to our action. Nevertheless,
we are responding to the comment.
We disagree with the commenter. We believe the BART guidelines
adequately define criteria and a process for determining the
feasibility of employing particular control technology or meeting
particular emission limits. These guidelines are similar to guidelines
for establishing BACT for a new source or source modification,
guidelines that have been used successfully on many occasions to
establish emission limits in the PSD program. Whether or not the BART
guidelines have been used successfully in the stack height context does
not mean the guidelines are inadequate or overly vague. It is true that
the State and EPA retain discretion to review and approve a source
demonstration regarding feasibility and BART, but this is true in the
PSD context and other contexts as well. Certainly our discretion is
limited by applicable standards under the Administrative Procedure Act.
Contrary to the commenter's assertion, we did provide information
regarding BART and infeasibility showings (see document #'s II.C-12 and
IV.C-40). It seems the commenter expected us to propose an alternative
BART limit for MSCC. However, the regulations make clear that in the
first instance the source must demonstrate that it cannot meet the NSPS
limit. MSCC did not attempt to make such a showing.
[[Page 22219]]
(b) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 24; MSCC letter, document # IV.A-20, comment # 1.I) stated
that SIP time frames, and threatened sanctions, preclude the use of
alternative limits for above-formula sources. The commenter stated that
because of this, the NRDC v. Thomas court should review its decision.
Response: We believe that a source and state could develop an
alternative emission limit in the time frame for SIP development. In
any event, we believe this comment goes to the validity of the stack
height regulations themselves, and is neither timely nor relevant to
our action on the SIP before us. We note that MSCC and the State had
more than ample time to conduct an infeasibility analysis in this case.
We informed the State of our position regarding the NSPS and the stack
height regulations in May of 1996, and subsequently invited MSCC and
the State to make an infeasibility showing. MSCC had over three years
in which to make such a showing before we finally proposed our action
on the SIP in July of 1999.
(c) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 24, 25) stated that section 123 requires EPA to promulgate
regulations defining GEP and that EPA cannot define the parameters for
a feasibility analysis through guidance or staff pronouncements. The
commenter went on to say that if section 123 of the Act grants power to
EPA employees to define GEP or feasibility analyses outside of
regulations, it is so broad a delegation of power as to deny reasonable
due process.
Response: The commenter is asserting a harm to MSCC that is purely
speculative. MSCC did not attempt to perform an infeasibility analysis,
the State did not adopt an alternative (to NSPS) limit for MSCC, and
the State did not submit such a limit to us for approval as part of the
SIP. The commenter assumes there was insufficient time to make the
necessary showing and analysis and assumes that we would have acted
arbitrarily and capriciously if the State had submitted an alternative
limit for MSCC. The commenter is raising an issue that is unripe for
review and has no relevance to our action on the SIP before us. Also,
the commenter ignores the fact that in the preamble to our stack height
regulations, we stated that we would rely on our BART guidelines in
reviewing any rebuttals to the NSPS and alternative limits (see 50 FR
27898), and that NRDC challenged our intent to rely on the BART
guidelines. The D.C. Circuit held that the BART guidelines did not
represent final agency action subject to review and dismissed NRDC's
challenge (NRDC v. Thomas, 838 F.2d 1224, 1241, fn. 14 (D.C. Cir.
1988)), but the Court upheld our regulations.
(d) Comment: One commenter (MSCC letter, document # IV.A-19, p. 2)
asserted that it is MSCCs ``situation, not merely its position'' that
application of additional control technology is infeasible to achieve
short term limits more restrictive than the current plan provides. The
commenter stated that MSCC lacks the land and resources to further
control SO2. The commenter stated that it has invested substantial
resources in reliance on the State's plan and findings.
Response: We are not permitted to consider economic or feasibility
questions in evaluating the adequacy of a SIP. Union Electric v. EPA,
427 U.S. 246, 265--266 (1976). To the extent the commenter is
suggesting MSCC should be allowed to use an alternative limit under our
stack height regulations, MSCC has not demonstrated, and the State has
not found, that MSCC cannot meet an NSPS limit. These are prerequisites
before an alternative limit may be established. See 40 CFR
51.100(kk)(1). In fact, despite being offered the opportunity (see
document # II.C-12), MSCC did not attempt to make an infeasibility
showing.
We also note that when MSCC contested the State-proposed emission
limit based on 65-meter stack height credit, MSCC claimed it was not
``economically practical or feasible'' to install an additional Claus
unit; yet, MSCC has since installed an additional Claus unit. Document
# IV.A-17, MSCC Exhibit 126, Direct Testimony of Larry Zink, ``In the
Matter of the Application of the DEQ for Revision of the Montana State
Air Quality Control of SO2 Emissions in the Billings/Laurel Area * *
*'', December 5, 1995, pp. 27, 36.
(e) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 101) asked a number of questions about the Asarco stack
height situation in Montana and the outcome of any BART analysis for
Asarco, and asked EPA to define the terms ``well-controlled'' and
``infeasibility.''
Response: The comment is more in the nature of a set of
interrogatories than a comment. We are responding to comments but are
not obligated to respond to interrogatories in conducting this
rulemaking action. In any event, we believe the questions posed are not
relevant to this rulemaking action, particularly since MSCC chose not
to try to make an infeasibility showing and establish an alternative
emission limit for the MSCC stack. However, Asarco did not perform a
BART analysis but instead assumed a de minimis stack height credit of
65 meters for the blast furnace stack in the attainment demonstration.
We approved the 65 meter stack height credit for the blast furnace
stack on January 27, 1995 (60 FR 5313).
3. Issues Related to the Montana Ambient Air Quality Standard (MAAQS)
Montana approved a stack height credit of 97.5 meters for MSCC's
100-meter stack based on a fluid modeling demonstration that MSCC's
contractor (CPP) performed. Assuming an NSPS rate of emissions from the
100-meter stack, and adding in background concentrations, the
particular demonstration the State approved showed an exceedance of the
annual Montana Ambient Air Quality Standard (MAAQS) for SO2 (52
micrograms per cubic meter), but not of the annual NAAQS for SO2 (80
micrograms per cubic meter). As we explained in our proposed
disapproval and TSD, our regulations require a fluid modeling
demonstration under 40 CFR 51.100(kk)(1) to show an exceedance of the
NAAQS. An exceedance of the MAAQS is not sufficient. We received
numerous comments on this issue and have considered them. Nothing in
the comments has caused us to change our position on this issue.
(a) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 95) stated that the use of the MAAQS is not logically
inconsistent for the fluid modeling determination. The commenter argued
that the State applied more stringent modeling requirements than were
warranted.
Response: We continue to believe our interpretation, that the
benchmark for fluid modeling must be the NAAQS, is reasonable and
should be maintained. In the alternative, if a benchmark like the MAAQS
is going to be used to justify higher stack height credit in a
federally enforceable SIP, then the State must consistently apply the
MAAQS in that SIP. This is not the case with the Billings/Laurel SO2
SIP; the SIP is not intended or designed to achieve the MAAQS. The
State cannot selectively choose to apply the MAAQS for inflating stack
height credit, thereby increasing atmospheric loading and dispersion
downwind, but not apply the more stringent ambient standard in setting
SIP emission limits. Either the MAAQS are a health-based standard for
SIP purposes or they are not.
We are not sure what the commenter is referring to when he claims
that the State imposed more stringent modeling
[[Page 22220]]
requirements than it had to, but we believe that this claim does not
resolve the issue related to the MAAQS or undermine our interpretation.
(b) Comment: Several commenters (MSCC letter, document # IV.A-19,
comment # 95; State letter, document # IV.A-23, p. 15; Goetz letter,
document # IV.A-18, exhibit D, p. 27; CPP letter, document # IV.A-18,
exhibit A, p. 6) stated that EPA's rules define excess concentrations
in terms of an impact on ``an ambient air quality standard,'' not a
``national standard'' or ``national ambient air quality standard.''
According to the commenters, the term ambient air quality standard
clearly includes the MAAQS. The commenters asserted that because the
rule is clear, it is not necessary to resort to the preamble to
interpret it. The commenters claimed that even if one examines the
preamble, the preamble supports the interpretation that ``ambient air
quality standard'' includes the MAAQS. Furthermore, the commenters
stated that if EPA had wanted to limit a fluid modeling demonstration
to the NAAQS, it knew how to do so. One of the commenters (MSCC)
asserted that neither the statute nor EPA regulations specify the
NAAQS. Finally, the commenters argue that EPA recognized in a 1990
memorandum that the express language of the rules is not limited to the
NAAQS, and that, on a case-by-case basis a more stringent state
standard could be used.
Response: Given that ``ambient air quality standard'' is not a
defined term in the regulations, we think it is entirely appropriate to
consult the preamble and other documents. The preamble to the
regulations clearly indicates that ``ambient air quality standard'', as
used in 40 CFR 51.100(kk)(1), was intended to mean a NAAQS. For
example, we stated the following in the preamble to the final
regulations:
For these reasons, we are requiring sources seeking credit for
stacks above formula height and credit for any stack height
justified by terrain effects to show by field studies or fluid
modeling that this height is needed to avoid a 40-percent increase
in concentrations due to downwash and that such an increase would
result in exceedance of air quality standards or applicable PSD
increments. This will restrict stack height credit in this context
to cases where the downwash avoided is specified by regulation or by
act of Congress as possessing health or welfare significance. (50 FR
27898, July 8, 1985, emphasis added.)
When we promulgated the regulation, we were not contemplating state
air quality standards. In fact, the preamble specifically mentions the
NAAQS in many places without any reference to possible alternative
state ambient standards. The following quotes are informative:
The EPA's reliance on exceedances, rather than violations of the
NAAQS and PSD increments, is deliberate. (50 FR 27898.)
Since a source can only get stack height credit to the extent
that it is needed to avoid a PSD increment or NAAQS exceedance, * *
* (50 FR 27898)
[T]he second way to justify raising a stack is to demonstrate by
fluid modeling or field study an increase in concentrations due to
downwash that is at least 40-percent in excess of concentrations in
the absence of such downwash and in excess of the applicable NAAQS
or PSD increments. (50 FR 27899)
Likewise, our response to comments document for the stack height
regulation states that it would not be appropriate to use a
concentration below the NAAQS ``as a precaution to avoid health and
welfare effects,'' because doing so would not be responsive to the
health and welfare concerns articulated by the Sierra Club court
(Sierra Club v. EPA, 719 F.2d 436 (D.C. Cir. 1983). Response to
Comments on the November 9, 1984, Proposed Stack Height Rules, prepared
July 1985 by EPA's Office of Air Quality Planning and Standards, at 36
(document # II.A-8).
The preamble to our proposed stack height regulation is also on
point. The term ``ambient air quality standard'' was used in the
proposed regulations exactly as it is used in the final regulations.
The preamble to the proposal describes the requirements as follows:
The proposed regulation requires that the downwash, wakes, or
eddy effects induced by nearby structures or terrain features
results in an increase in ground-level pollutant concentrations
that: (a) Causes or contributes to an exceedance of a NAAQS or
applicable PSD increment; * * *
Because the NAAQS represent pollutant concentrations which the
Agency has previously determined to result in adverse health and
welfare effects, the inclusion of the exceedance of a NAAQS in the
definition of ``excessive concentrations'' provides a
straightforward response to the court's directive. (49 FR 44881,
November 9, 1984)
It is clear that we interpreted ambient air quality standard to
mean NAAQS. This is how the United States Court of Appeals for the D.C.
Circuit understood the regulations (see NRDC v. Thomas, 838 F.2d 1224,
1240 (D.C. Cir. 1988)) and this interpretation is supported by other
documents as well. The 1990 memo (document # II.F-13) referenced by one
commenter (State) states that EPA interprets ``ambient air quality
standard'' to mean national ambient air quality standard. To the extent
the memo allowed for consideration of some other benchmark on a case-
by-case basis, we believe that the State has not made an adequate
showing that use of the MAAQS in this case is justified or would result
in more stringent requirements than our regulations impose. In fact,
just the opposite would be the case.
We also note that the March 4, 1991 letter to which we attached the
1990 memo stated our conclusion that Asarco's field studies had not
demonstrated that stack height above GEP formula height was justified.
Among the reasons we gave for reaching this conclusion was that the
studies had not shown an exceedance of the 3-hour national ambient air
quality standards for SO2. (March 4, 1991 letter from Irwin L.
Dickstein to Jeffrey T. Chaffee (document # II.F-14), emphasis added.)
Also, in our September 16, 1994 letter from Douglas Skie to Jeffrey
Chaffee regarding ExxonMobil's GEP stack height credit (document #
IV.A-17, MSCC Exhibit 123) we stated that the definition of ``excessive
concentrations'' required an exceedance of the applicable NAAQS.
We also find it striking that more than one of the commenters, in
objecting to other aspects of our stack height analysis, rely on EPA
documents that clearly contemplate use of the NAAQS in fluid modeling
demonstrations. For example, one commenter (Goetz, document # IV.A-18,
exhibit D, pp. 24--26) cites extensively from our Guideline for
Determination of Good Engineering Practice Stack Height (Technical
Support Document for the Stack Height Regulations), which, in Table
3.1, item F, clearly indicates that excessive concentration is to be
judged against the NAAQS. The State (document # IV.A-23, p. 20,
footnote 19) refers to an October 6, 1988 letter from Marcia Mulkey,
EPA Region III, to John Proctor, attorney for Pennsylvania Electric
Company (document # IV.C-65), which indicates our stack height
regulations require an analysis of whether downwash causes an
exceedance of an applicable NAAQS. These commenters never mention these
references to the need to use the NAAQS.
It is true that the statute does not specify the NAAQS in referring
to excessive concentrations. However, this is irrelevant because
Congress did not define excessive concentrations at all and instead
left it to EPA to promulgate regulations to address issues related to
stack height demonstrations.
The State and other commenters have merely assumed that the phrase
``ambient air quality standard'' encompasses a state-adopted ambient
air quality standard. However, they offer
[[Page 22221]]
no compelling reason that their interpretation of our regulation is
reasonable. On the other hand, we have a compelling reason that our
longstanding interpretation of the phrase is reasonable--namely, that
our interpretation will effectuate Congressional purpose, as
interpreted by the courts and by EPA. Our interpretation is entitled to
deference.
(c) Comment: More than one commenter (MSCC letter, document # IV.A-
19, #'s 18, 95; MSCC letter, document # IV.A-20, # 1.B; State letter,
document # IV.A-23, p. 15) stated that EPA has already approved into
the SIP Montana's stack height regulations, which are essentially
equivalent to those of the federal government, and which allow the
MAAQS to be used in fluid modeling demonstrations. The commenters
claimed that if EPA had intended that the NAAQS must be used in place
of the MAAQS in a fluid modeling demonstration, EPA would have
disapproved the part of Montana's rules that cross-reference the MAAQS.
Furthermore, the commenters asserted that EPA has delegated the
authority for such determinations to the state of Montana.
Response: First, we do not believe we are bound by the terms of the
Montana stack height regulations in reviewing the Billings/Laurel SIP.
Instead, we believe we have an independent obligation to ensure that
the Billings/Laurel SIP meets the requirements of section 123 of the
Act and our stack height regulations, regardless of the terms of the
stack height regulations in the State SIP. The Court of Appeals for the
D.C. Circuit said as much in Sierra Club v. EPA, 719 F.2d 436, 469
(D.C. Cir. 1983):
Moreover, we see no place for such state regulations in EPA's
own final regulations. The regulations are detailed and precise and
do not mention alternative means of compliance from which the states
may pick and choose.
As we noted in our proposal, we believe our regulations intended
``ambient air quality standard'' to refer to the NAAQS. The preamble
makes this evident. Also, the application of the MAAQS in a fluid
modeling demonstration makes it easier for a source to demonstrate
excessive concentrations, as defined in our stack height regulations,
and thus justify an above-formula stack height credit. Clearly, we did
not intend such a result, particularly where, as in this case, the SIP
revision has not even been designed to attain the substitute ambient
standard (the MAAQS).
No commenter has pointed to any limits or plan that is designed to
achieve the MAAQS, and in reading the State's regulations, we have
found no requirement for a plan. Instead, it is not clear how the MAAQS
are enforced by the State.
Assuming for the sake of argument that we are bound by the Montana
SIP stack height regulations, we do not think those regulations stand
for the proposition argued by the commenters. Following our
promulgation of our July 8, 1985 stack height regulations, we approved
Montana's stack height regulations (16.8.1204 through 16.8.1206, ARM,
effective June 13, 1986) as part of the SIP on June 7, 1989 (see 40 CFR
52.1370(c)(18), 54 FR 24334). That version of the Montana regulations
cross-references ``an ambient air quality standard as provided in
subchapter 8.'' See document # IV.C-45. Subchapter 8 was not submitted
as part of the SIP. When we approved Montana's stack height regulations
in 1989, subchapter 8 exempted the Billings/Laurel area from the MAAQS.
See document # IV.C-70.\27\ This is because in 1987, the Montana
legislature enacted the ``Hannah Bill,'' which directed the Montana
Board of Health and Environmental Sciences to amend subchapter 8 to
exempt Billings/Laurel sources from the SO2 MAAQS. See document # IV.C-
67. Following this directive, the Board of Health and Environmental
Sciences revised subchapter 8 of the air quality regulations, effective
August 28, 1987. See document # IV.C-70. Thus, when we approved the
Montana stack height regulations, only the SO2 NAAQS applied in the
Billings/Laurel area.
---------------------------------------------------------------------------
\27\ Subchapter 8 described this exemption in a rather oblique
fashion, by indicating that persons causing or contributing to
exceedances of the MAAQS during 1985 would only need to meet the
NAAQS for SO2, not the MAAQS. See document # IV.C-70. This language
was specifically designed for the Billings/Laurel area, which
exceeded the MAAQS for SO2 in 1985. See Montana 1986 Network Review,
document # IV.C-68.
---------------------------------------------------------------------------
Given that the NAAQS applied in the Billings/Laurel area as a
matter of State law at the time we approved the Montana stack height
regulations, we believe it is reasonable to interpret the federally-
approved Montana stack height regulations as requiring the use of the
NAAQS in fluid modeling demonstrations. At the very least, the
applicable ambient air quality standard has been a moving target under
Montana law. As recently as 1997, the State air quality regulations
continued to exempt the Billings/Laurel area from the MAAQS. See
document # IV.C-77. This exemption was in effect when MSCC conducted
fluid modeling in 1995 and 1996, and when the State adopted SIP limits
for MSCC in the summer of 1996. The State did not remove the Hannah
exemption from its regulations until September 1997. See document #
IV.C-77.
According to the State, subchapter 2 is the present successor to
subchapter 8. See State letter, document # IV.A-23, p. 15. As the State
notes in its comments, subchapter 2 not only contains the MAAQS, but
also incorporates the NAAQS by reference. State letter, document #
IV.A-23, p. 16, footnote 16. The NAAQS are clearly within the
definition of an ``ambient air quality standard'' as used in the
State's current stack height regulation. See document # IV.C-64,
section 17.8.201(2). Even if this version of the State regulation could
be considered to govern this situation, under its own regulation, the
State has a choice of ambient standards to apply. The State, in its
comments, offers no basis to choose the MAAQS over the NAAQS for
purposes of making a fluid modeling demonstration. We believe it is
rational and necessary to choose the NAAQS when establishing stack
height credit for purposes of setting a limit to achieve the NAAQS. The
State has offered no rational basis for selecting the MAAQS for this
purpose, and under our reading of the relevant laws, and the purposes
behind section 123 of the CAA, it was inappropriate for the State to
select the MAAQS. This merely made it easier for MSCC to demonstrate an
``excessive concentration'' and higher stack height credit.
In response to the comment claiming delegation, we have not
``delegated'' to Montana sole discretion to determine GEP stack height.
We are required to independently determine whether this SIP revision
meets the requirements of section 123 of the CAA, independent of any
determination made by the State. See sections 110(k)(3) and 123 of the
Act.
(d) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 48; MSCC letter, document # IV.A-20, comment # 1.C) stated
that EPA's objections to use of the MAAQS in MSCC's fluid modeling
demonstration are spurious. The commenter asserted that lack of federal
enforceability does not make the MAAQS irrelevant in a fluid modeling
demonstration, any more so than a nuisance demonstration by a state
need be based on a federally enforceable ``nuisance'' concentration as
provided in another part of the rule.
Response: Taken to its logical conclusion, the commenter's argument
would mean it would be acceptable for a state to establish an ambient
standard of zero for purposes of fluid modeling demonstrations, that
would be unenforceable through the SIP. Such a
[[Page 22222]]
zero standard would make the ambient air quality standard portion of
the rule meaningless, leaving only the 40% standard for fluid modeling
demonstrations. This is clearly not acceptable, as the Sierra Club
court held in requiring that EPA revise the rule using a health-based
requirement for fluid modeling demonstrations. See Sierra Club v. EPA,
719 F.2d 436, 446-450 (D.C. Cir. 1983). We believe our interpretation
of the rule is reasonable--at the very least, the ambient air quality
standard must be cognizable under the SIP. Otherwise, states will be
able to circumvent the purposes of the rule--to prevent states from
achieving local compliance with the NAAQS at the expense of downwind
states and to prohibit inappropriate use of dispersion instead of
emissions control.
The commenter's attempt to analogize a nuisance showing under 40
CFR 51.100(kk)(2) fails because (kk)(2) applies to within formula
demonstrations, for which EPA consciously selected a less rigorous
standard. In order to preserve Congressional and EPA intent regarding
the granting of above-formula stack height credit, the ambient air
quality standard referred to in 40 CFR 51.100(kk)(1) must at least be
federally cognizable through the SIP.
(e) Comment: Several commenters (MSCC letter, document # IV.A-19,
comment #s 48, 93; Goetz letter, document # IV.A-18, exhibit D, pp. 21,
27, 28) stated that EPA's modeler advised the State that use of the
MAAQS would be acceptable in the fluid modeling demonstration.
According to one of the commenters (Goetz), in a telephone conversation
with Dr. Petersen in the Spring of 1996, EPA's modeler indicated that
EPA was going to agree with the State's recommendation that a MAAQS
exceedance demonstration is sufficient and that the regulation
``clearly says an exceedance of an ambient standard which MAAQS is.''
Another commenter (CPP letter, document # IV.A-18, exhibit A, p. 6)
made essentially the same claim. Mr. Goetz asserted that EPA's
objection to use of the MAAQS is trivial, something EPA's modeler
recognized.
Response: Although EPA's modeler \28\ may have at one time
indicated that the use of the MAAQS would probably be acceptable, the
official EPA position is that use of the MAAQS is not consistent with
the stack height regulations. Our other responses in this document
explain why the use of the MAAQS is not appropriate. We note that we
had raised the issue of using the MAAQS in a March 15, 1996 letter
(document # II.F-20) to the State that Mr. Goetz cites for other
purposes. Our modeler did not indicate that the issue was trivial, and
we do not believe our objection to the use of the MAAQS is trivial.
---------------------------------------------------------------------------
\28\ Elsewhere we and some of the commenters also refer to EPA's
or the Region's meteorologist. Our modeler and meteorologist are the
same person.
---------------------------------------------------------------------------
(f) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 93, 95) argued that the MAAQS are cognizable under federal
law and that EPA's position regarding the MAAQS makes no sense given
that fluid modeling demonstrations can justify above-formula credit
based on an exceedance of the PSD increment which is much smaller than
the NAAQS or MAAQS. According to the commenter, the rules do not
contain the restrictions EPA asserted, and section 123 of the Act makes
no mention of ambient standard.
Response: For the reasons discussed elsewhere in this document, we
do not agree that the MAAQS are ``cognizable'' under federal law. We
have no mechanism to ensure the MAAQS will be met. Regarding the use of
the PSD increment in fluid modeling, this is only available to sources
that are subject to PSD (see 40 CFR 51.100(kk)(1); Response to Comments
on the November 9, 1984 Proposed Stack Height Rules, July 1985, at pp.
32, 38, document # II.A-8), and, thus, that have already installed
BACT. Thus, these sources have already been controlled to at least NSPS
levels, and usually well beyond. See 40 CFR 51.166(b)(12). In addition,
unlike the MAAQS, PSD increments are federally enforceable standards
that are addressed in SIPs. It is irrelevant that section 123 does not
mention ``ambient standard;'' our regulations do use the term.
(g) Comment: One commenter (State letter, document # IV.A-23, p.
16) stated that EPA did not adopt rules that required use of the NAAQS
in the fluid modeling demonstration, or disapprove a provision in the
Montana SIP that allowed use of the MAAQS, because to do so would be
contrary to section 116 of the CAA, which expressly recognizes that
states may adopt and enforce standards, such as the MAAQS, that are
more stringent than federal standards.
Response: First, as explained in response to a prior comment, we
did adopt a rule that requires the use of the NAAQS in a fluid modeling
demonstration. Second, there is nothing in section 116 that would
prevent EPA from doing so or that would prevent EPA from disapproving a
provision in a SIP that allows use of a lower air quality standard in a
fluid modeling demonstration. Section 116 reserves to states the right
to generally adopt requirements more stringent than federally required,
except in certain pre-empted areas. See Union Electric Co. v. EPA, 427
U.S. 246, 263--264 (1976). The State's use of the MAAQS to artificially
inflate GEP stack height credit without concomitantly regulating for
the MAAQS in the SIP renders the Billings/Laurel SIP less stringent
than federally required.
Our establishment of the NAAQS as the fluid modeling benchmark has
no effect on the ability of a State to establish a lower State ambient
air quality standard to provide a greater margin of protection to its
citizens. Our establishment of the NAAQS as the benchmark for fluid
modeling, may have the effect, in certain instances, of restricting the
degree to which dispersion using stack height can be counted for
purposes of showing compliance with the national ambient air quality
standards. Thus, the issue here is the extent to which dispersion may
be relied on to show compliance with national standards, not whether
Montana can impose more stringent requirements on its sources to meet a
more stringent Montana standard. There is nothing in section 116 that
says Montana or any other state is entitled to rely on greater
dispersion to meet the NAAQS, and Montana's use of the MAAQS in this
case to justify greater use of dispersion renders the SIP less
stringent, not more. Montana's use of the MAAQS would allow MSCC to
have a higher SIP limit, not a lower one. If the NAAQS were used, MSCC
would have a lower stack height credit. Section 116 does not support
the commenters' argument.
(h) Comment: One commenter (State letter, document # IV.A-23, p.
17) stated that EPA's criticism of the State's use of the MAAQS in the
fluid modeling demonstration arises from EPA's lack of understanding of
the MAAQS. The commenter asserted that the State has responsibility to
protect both the NAAQS and the MAAQS; the NAAQS are enforced through an
implementation plan, but the MAAQS are enforced directly, based on
ambient monitoring. According to the commenter, if EPA's argument were
followed to its logical conclusion, Montana would be forced to either
abandon its MAAQS or impose two GEP determinations upon a source
seeking above formula credit, separately based on the NAAQS and the
MAAQS.
Response: The comment makes clear that stack height credit has no
relevance to the MAAQS whatsoever. As the comment notes, the MAAQS are
enforced directly, based on ambient monitoring. Of necessity, the full
[[Page 22223]]
dispersive effect of a stack's height is taken into account with
ambient monitoring. A monitor does not adjust the concentrations it
reads based on too much stack height credit. Stack height credit only
has relevance to developing limits in an implementation plan, and, as
Montana admits in its comment, no implementation plan is developed for
the MAAQS. Thus, our position would not force Montana to abandon the
MAAQS and would not force Montana to perform two GEP determinations.
If Montana were to develop a state-only plan for the MAAQS, it is
conceivable that Montana would have to perform two GEP determinations--
one for the federally enforceable SIP for the NAAQS, one for the state-
only plan for the MAAQS. We do not believe this would impose a
significant hardship on the State or sources. Many states have state-
only requirements for sources that they choose not to include in the
federally enforceable SIP. Certainly, our position would not force
Montana to abandon the MAAQS.
(i) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 1.D) believed that EPA's objections regarding the use of the
MAAQS in the fluid modeling demonstration and with respect to other
aspects of the State's GEP stack height determination are too late.
Response: We have both the legal authority and obligation to
determine whether the SIP meets the requirements of the Act and our
regulations. At the time we propose action on a SIP submission, it is
clearly not ``too late'' to raise objections regarding the SIP, even if
we did not raise these objections at an earlier date. We are not
``estopped'' from taking action consistent with the Act and
regulations.
4. Issues Related to the Support Structure
We received many comments, primarily from MSCC and its consultants,
related to MSCC's stack support structure. There are two fundamental
issues related to the support structure--first, whether we must approve
GEP stack height credit for MSCC's SRU 100-meter stack based on the
application of the formula to the stack support structure, either by
accepting the formula calculation outright or by accepting a within-
formula fluid modeling demonstration to verify formula height based on
the support structure, and second, whether we are justified in
disapproving MSCC's SRU 100-meter stack emission limits because MSCC
modeled downwash from the stack support structure in conducting its
wind tunnel study.
We think the first issue is irrelevant to our action. This is
because the State rejected the application of the formula to the stack
support structure. Thus, the State did not submit a SIP limit for MSCC
based on a formula height determination, or a within-formula fluid
modeling demonstration. Our obligation under the Act is to evaluate the
SIP the State has submitted to us, not GEP theories an individual
source has proposed but the State has rejected. Nonetheless, we respond
to the comments on the first issue and explain why we believe the stack
support structure may not be used to calculate formula height.
The second issue is relevant to our action because the fluid
modeling demonstration that the State ultimately approved modeled
downwash from the stack support structure. We respond to comments on
this issue and explain why we think it was inappropriate to model such
downwash under section 123 of the Act and our regulations. This error
forms one basis for our disapproval of MSCC's limits.
(a) Comment: Several commenters (MSCC letter, document # IV.A-19,
comment #'s 27, 30, 38; MSCC letter, document # IV.A-20, comment #'s
1.D, 1.E, 2.B, 2.C, and 2.U; Goetz letter, document # IV.A-18, exhibit
D, pp. 33--34; CPP letter, document # IV.A-18, exhibit A, p. 5 and
Attachment I) stated that EPA has wrongly concluded that the MSCC stack
support structure should not be treated as a nearby structure for
purposes of determining formula height. The commenters claimed that
nothing in the stack height regulations supports the State's and EPA's
argument that the support structure is not within the definition of
``nearby,'' and that in reaching such conclusion, EPA ignored the plain
language of the regulations. The commenters also asserted that the
stack height regulations do not exclude any types of structures for
determining formula height. One of the commenters (MSCC) noted that EPA
eliminated nearby terrain from consideration and could have done the
same for specific structures if it had wanted to. The commenter
contended that even if the support structure were a stack, it would
still be a structure, and should still be considered in formula
determinations and fluid modeling demonstrations. The commenter claimed
that the rule does not draw a distinction between structures that are
stacks and other structures, and that if it had drawn such a
distinction, it would reasonably have been challenged as contrary to
the explicit language in section 123, which requires that nearby
structures, terrain and the source itself be considered in determining
GEP. The commenter claimed that EPA cannot now put forward an
interpretation that is not embodied in the rule. One of the commenters
(MSCC) argued that section 123 contemplates consideration of downwash
caused by the source itself. The commenter claimed it would be absurd
to conclude that this would exclude the stack at a source but no other
structures.
Response: We do not dispute that the support structure is within
the distance that 40 CFR 51.100(jj) defines as ``nearby'' with respect
to separate structures. However, we cannot allow the support structure
to be used to calculate formula height because it is not separate from
the stack; it is part of the stack. Sources are not free under section
123 to justify greater stack height credit by relying on the height of
an existing stack or building a taller stack. Congress recognized the
distinction between a source and its stack when it provided in section
123 of the Act that formula height could not exceed two and a half
times the height of the source. It is self-evident that Congress did
not mean to include the stack as part of the source for applying the
``2.5H'' formula. The D.C. Circuit acknowledged this in Sierra Club v.
EPA:
While the statute generally left the determination of GEP stack
height to regulations to be promulgated by the EPA Administrator, it
set an upper limit of two-and-one-half times the height of the
stack's source.''
719 F.2d 436, 442 (D.C. Cir. 1983).
If the commenters' logic were applied, a source could continually
justify a higher and higher stack height credit, up to the moon if it
wished, by simply building a taller stack. This result would completely
undercut section 123 of the Act, which uses the formula to establish a
presumptive limit on stack height credit.
In addition, the very use of the term ``nearby'' in the regulations
indicates a structure separate from the stack. Furthermore, the stack
height regulations do not define the term ``structure'' and there is no
statement in the regulations that says any and every manmade feature
must be considered in calculating formula height. For example, we
believe it would be inappropriate to calculate formula height based on
a flagpole, even though it might be separate from the stack and some
would argue it is a structure. As we discuss more fully below, we
specifically indicated in the Technical Support Document for the stack
height
[[Page 22224]]
regulations that stacks and radio or TV transmission towers should not
be considered in GEP stack height determinations. (See ``Guideline for
Determination of Good Engineering Practice Stack Height (Technical
Support Document For the Stack Height Regulations)'' (document # II.A-
12) at p. 7). Absent a specific regulatory definition of the term
``structure,'' we believe we have the discretion and the obligation to
interpret our regulations so as to effectuate the language of the
statute and the intent of Congress. We believe our interpretation is
entitled to deference, and believe the commenters' interpretation would
do severe damage to the statutory framework.
(b) Comment: One commenter (CPP letter, document # IV.A-18, exhibit
A, Attachment I) asserted that the State and EPA incorrectly concluded
that the stack support structure could not be used to calculate GEP
formula height. The commenter stated that mathematically, there is no
reason the stack support structure cannot be used for calculating GEP
formula height, since it has both height and width, and a formula can
be calculated for any structure with height and width.
Response: We are well aware that structures, like the MSCC stack,
have height and width dimensions and that the variables in the GEP
formula are height and width. We understand that it is possible to plug
the height and width of the stack support structure into the GEP
formula to reach a mathematical result. But, based on our legal
interpretation of section 123 of the Act and our regulations, we do not
believe this mathematical result is supportable; as explained in
response to the previous comment, stack dimensions may not be used to
calculate GEP formula height. The support structure is merely part of
the MSCC stack.
(c) Comment: One commenter (MSCC letter, document # IV.A-19,
comment #'s 29, 30; MSCC letter, document # IV.A-20, comment # 2.E)
stated that the stack support structure is part of the source, not the
stack. The commenter asserted that EPA's suggestion that the structure
is a stack or part of a stack is both incorrect and spurious. The
commenter also asserted that by definition under 40 CFR 51.100, the
support structure is not a stack, ``which is a vent or conduit for
emissions.'' The commenter claimed that the support structure simply
supports several items of equipment that are themselves, like the
structure, part of the source. Another commenter (Goetz letter,
document # IV.A-18, exhibit D, p. 35) also claimed that the definition
of stack does not support the argument of EPA and the State that the
cylindrical support structure is a stack itself.
Response: We disagree with the commenter's characterization of the
support structure; we believe it must be considered part of the stack.
As one commenter notes, the State and EPA are in agreement on this
point. We believe that the agencies' view that the support structure is
part of the stack is well-supported by evidence in the record, in
particular, MSCC's own photographs of the stack (document # IV.A-17,
MSCC Exhibit 119). These photographs show that the support structure
and flue are nearly the same diameter and rise together for most of the
height of the stack. In fact, they rise together for some 310 feet--
more than a football field--before the flue emerges for a final 18
feet. See June 27, 1994 EPA letter, document # II.F-15; Goetz letter,
document # IV.A-18, exhibit D, pp. 33-34. Therefore, the support
structure cannot be considered a nearby structure for formula purposes
or fluid modeling purposes. By analogy, a power plant with a stack
consisting of an inner stack lining constructed of brick and an outer
stack chimney constructed of concrete would not be allowed to calculate
formula stack height based on the outer chimney, nor would the power
plant be allowed to model downwash from the outer chimney in a fluid
modeling demonstration. There is no reason MSCC's outer metal support
structure should be treated any differently than the outer concrete
chimney at a power plant. Both structures are part of the stack, even
though both may support other equipment.
For the purposes of accuracy, we'd like to point out that 40 CFR
51.100 does not define stack as ``a vent or conduit for emissions.''
Instead 40 CFR 51.100(ff) defines stack as ``any point in a source
designed to emit solids, liquids, or gases into the air, including a
pipe or duct but not including flares.'' We believe this definition
encompasses the entire MSCC stack structure, which includes the support
structure.
The commenter's assertion that ``the structure simply supports
several items of equipment that are themselves, like the structure,
part of the source,'' seems a bit misleading. The commenter fails to
mention that MSCC itself calls the structure the ``support structure''
or the ``stack support'', and that the main structure the support
structure supports is the flue. See, e.g., ``Rebuttal Testimony of
Larry Zink, Vice President of Montana Sulphur & Chemical Company,''
document # IV.A-17, MSCC Exhibit 127, at p. 24.
(d) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 38; MSCC letter, document # IV.A-20, p. 5, footnote 6)
objected to the fact that EPA rejects the use of the support structure
as a basis for calculating formula height on the basis that this would
allow the stack to justify itself. The commenter stated that this
concept or phrase is not found in the rules, statute, or legislative
history. The commenter suggested that EPA's ``speculations'' regarding
a stack justifying itself appear irrelevant to the concept of GEP and
the goals of the CAA as a whole and section 123 in particular.
According to the commenter, the use in the preamble of the phrase
``stack justifying itself'' only relates to the emission rate to be
used in fluid modeling demonstrations, and even there, EPA's arguments
are specious. The commenter also suggested that EPA's response to its
concern about circularity in the stack height regulations was an
improper adoption at the last minute of the NSPS emission rate, and
that EPA could have avoided the possibility of a new stack justifying
itself by adopting an emission rate based on existing stack height or
the de minimis stack height.
In asserting that the stack is part of the source, not separate
from the source, the commenter included various statements regarding
Congress' intent and suggested that EPA included many terms and
requirements in its stack height regulation that are not included in
the statute.
Response: Much of this comment appears to be saying that EPA went
beyond the statute when it promulgated the 1985 stack height
regulations and made questionable decisions. We believe such comments
are not timely and are not directly relevant to this action. As we have
explained elsewhere, the validity of the stack height regulations may
not be challenged in this action.
As to the remainder of the comment, we agree that neither section
123 of the Act nor the stack height regulations state, ``a stack may
not be used to justify itself in formula calculations,'' but the
validity of our position on this matter is evident from the language of
section 123 itself and the language and structure of our regulations.
As we have explained in response to a prior comment, section 123 treats
the stack as distinct from the source for purposes of calculating GEP
height. Under section 123, GEP height may not exceed two and a half
times the height of the source. For obvious reasons, Congress did not
say GEP stack height may not exceed two and half times the height of
the stack, because this would render the formula meaningless. Yet, this
is essentially
[[Page 22225]]
what the commenter is advocating. Also, the very use of the term
``nearby'' in the regulations indicates a structure separate from the
stack. In this instance, we believe the regulations must be interpreted
in a way to effectuate the overarching purpose of section 123, which is
to restrict the unnecessary use of dispersion through tall stacks in
lieu of emission controls; we believe our interpretation is reasonable
and entitled to deference.
Contrary to the commenter's assertion, we are not ``speculating''
about a stack justifying itself. MSCC is asserting in this action that
part of the stack should be plugged into the formula or should be
modeled in the fluid modeling demonstration.
Also, we are not relying on preamble language related to a stack
justifying itself or circularity to reach our conclusion; we are
relying on section 123 itself and the language and structure of the
regulations. The circularity we are concerned about here is not related
to emission rates used in a fluid modeling demonstration; we are
concerned with the circularity that arises from MSCC's attempt to
justify GEP stack height credit for a new 100-meter stack based on a
component of that very stack.
(e) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, pp. 36-37) stated that it is disingenuous for EPA to argue
that MSCC's logic is circular since the CAA and its implementing
regulations are circular and the NRDC v. Thomas court approved of some
circularity in the stack height regulations.
Response: We do not believe the court's holding on the differing
requirements for within-formula and above-formula stack height
demonstrations is particularly relevant to this issue. If it is
relevant, then, for the reasons we have already given, using the
support structure to calculate formula height is most certainly an
impermissible form of circularity.
(f) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, pp. 36-40) stated that the preamble to the 1981 stack height
regulations dispels EPA's ``intent'' argument (that MSCC's use of the
stack support structure to calculate formula height would violate
Congress' intent in passing section 123 of the Act), because it
indicated a lack of concern about sources manipulating structure size
or placement solely for the purpose of increasing their stack height
credits, and retained the definition of ``nearby.'' In addition, the
commenter claimed that in indicating Congress intended to favor
emission reductions over tall stacks, EPA mischaracterizes Congress'
intent; Congress endorsed the historic practice of using stacks to
protect health from downwash-induced pollution. Another commenter (MSCC
letter, document # IV.A-20, comment # 2.U; MSCC letter, document #
IV.A-19, comment # 92) stated that EPA's position regarding the support
structure is illogical because of the numerous other scenarios that
could occur whereby a source could increase formula height through its
own construction or have it increased through others' construction of
nearby sources. The commenter pointed out that construction of a new
source and its stack could occur simultaneously and that this would not
disqualify the source from being used to determine formula height.
Thus, in the commenter's view, EPA's complaint that MSCC's new stack
was not necessary as a result of some preexisting structure has no
merit.
Response: We agree that in the 1981 preamble and relevant EPA
guidance we have taken the position that formula height may be
recalculated based on the siting of new nearby structures. We do not
believe the preamble or guidance language addresses or contemplates the
situation involved here. This situation is distinct because the support
structure is merely a component of the stack structure.
We agree that some types of manipulation could occur, involving
location of structures that could impact formula calculations. Normally
we would not look behind the motivation for locating structures. As we
explained in the 1981 preamble language cited by one of the commenters
(Goetz at pp. 37-38; 46 FR 49819, October 7, 1981), we believed at that
time that sources would not normally manipulate source construction
parameters because it would be prohibitively costly to do so. We also
agree that the simultaneous construction of a source and its stack
would not invalidate a formula height calculation for the stack based
on the source dimensions. However, as we noted in the same 1981
preamble language cited by the commenter, new source construction would
normally be subject to stringent technology-based limits under NSPS or
new source review permitting, and thus, a source owner would have
little motivation to manipulate structure sizes and locations. The same
logic does not apply to MSCC's stack; MSCC was not building a new
source with its stack, MSCC was merely building a new stack.
We are not saying that MSCC manipulated the design of the stack
with the goal of increasing stack height credit; we are not familiar
with the specific design considerations that went into designing and
building the stack. However, because of the circumstances, this really
is not relevant. What is relevant is that there was no existing or new
nearby structure distinct from the stack at the time MSCC constructed
the stack that justified increasing the formula height of MSCC's stack.
We believe we have a valid statutory and regulatory basis to
distinguish between structures that are distinct from a stack and those
that are part of the stack; otherwise, section 123 of the Act and our
regulations would be rendered meaningless. As we have described in
response to other comments, our position is not just based on our
interpretation of Congress' intent, but on the language and structure
of section 123 and our regulations.
In any event, we do not believe we have mischaracterized Congress'
intent. Congress intended to strike a balance between the use of stacks
to disperse emissions and the use of control technology to limit
emissions. The use of the support structure to calculate formula height
would clearly disrupt the balance Congress was trying to achieve
because any source could justify greater stack height credit by merely
building a new stack.
(g) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 37) stated that EPA's arguments regarding MSCC's stack appear
to suggest that MSCC built or designed the structure to create
downwash. The commenter asserted that MSCC did not build or design the
structure to create downwash or circumvent the stack height regulations
and described many reasons why MSCC built the stack in the manner and
at the time it did.
Response: As a preliminary matter, we do not believe this comment
goes to the validity of our action. However, we offer the following
response. In our proposal, we did not intend to suggest that MSCC built
or designed the stack to create downwash. As noted above, we are not
familiar with the specific design considerations that went into
designing and building the stack. However, we are concerned that
allowing one source to model downwash from a stack support structure
might encourage other sources to design support structures that
increase downwash. Most importantly, we do not accept the proposition
that the stack support structure is a nearby structure under the Act
and our regulations.
(h) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 2.V) stated that the notion that the support structure is
part of the stack itself is not a meaningful distinction. According to
the commenter, there is nothing in the rule that would allow a
[[Page 22226]]
reader to determine at what point structures become part of the stack
itself as opposed to not part of the stack. The commenter claimed that
if this position were valid, the rule would be void for lack of clarity
as well as for lack of notice. The commenter asserted that these merely
functional issues are not relevant to determining downwash or excessive
concentrations; if a structure exists and it is nearby its contribution
to downwash is as real as any other structure regardless of function.
The commenter argued that the only purpose of this interpretation is to
deny MSCC credit above 65 meters, not serve the Act.
Response: As we explain in response to prior comments, we believe
it is necessary to distinguish between the stack and the source in
order to effectuate section 123 of the Act and our stack height
regulations. Otherwise, there is no meaningful limit on GEP stack
height credit. We do not believe it is particularly difficult in most
cases to distinguish the stack from the source. In MSCC's case, we have
already indicated why we believe it is evident that the support
structure and the flue form an integrated stack structure. We note that
it is necessary to determine the location and extent of the stack for
purposes of determining whether a structure is nearby under 40 CFR
51.100(jj), and under that section we would be unwilling to accept the
proposition that there is no distinction between the source and the
stack.
We do not believe the stack height regulations are void for lack of
clarity or notice. We do not believe any reasonable person reading the
stack height regulations would have understood them to allow a source
to increase formula height merely by building a new stack. In any
event, we do not believe the clarity of the stack height regulations or
validity of the notice for those regulations may be challenged in this
action.
The fact that the stack may create downwash is not a reason to
conclude that the stack dimensions should be used to calculate formula
height. We believe it is reasonably clear from the regulations that
nearby structures means structures other than the stack.
We believe very strongly that our interpretations serve the
purposes of the Act. We are not going to this effort merely to deny
MSCC stack height credit greater than 65 meters.
(i) Comment: Several commenters (MSCC letter, document # IV.A-19,
comment #'s 27, 38; MSCC letter, document # IV.A-20, comment # 2.I;
Goetz letter, document # IV.A-18, exhibit D, p. 34-35; CPP letter,
document # IV.A-18, exhibit A, p. 5 and Attachment I) contended their
arguments, that the support structure may be used to justify GEP stack
height credit through application of the formula or fluid modeling, are
supported by EPA's Guideline for Determination of Good Engineering
Practice Stack Height (Technical Support Document for the Stack Height
Regulations). The commenters claimed that EPA's guidance indicates that
tall thin structures may be used to calculate formula height and EPA's
approvals here and elsewhere have involved calculating formula height
from structures that are taller than they are wide.
Response: Contrary to the commenters' assertion, our ``Guideline
for Determination of Good Engineering Practice Stack Height (Technical
Support Document For the Stack Height Regulations)'' (document # II.A-
12) does not support the commenters' position. The Guideline
specifically states that ``structures such as stacks and radio or TV
transmission towers should not be considered in GEP stack height
determinations.'' (See Guideline at p. 7.) Later references to oddly
shaped structures and the need to use fluid modeling demonstrations do
not include stacks or radio and transmission towers. Thus, it is not
just that the support structure is part of the stack; it is also the
fact that it is very tall and thin that precludes its use in
determining formula height. Although commenters claim that the rule
does not exclude any nearby structures from consideration in
determining formula height, it is clear from the technical support
document for the stack height regulations that we intended to exclude
some structures.
We agree that, as a rule, formula height may be calculated based on
structures that are taller than they are wide. (However, as already
indicated, our interpretation is that this does not extend to
structures like stacks and radio or TV transmission towers.) We also
agree that formula height may be calculated based on enclosed
structures within a lattice. This does not change our opinion that the
formula may not be applied to the MSCC stack support structure.
(j) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, p. 35) stated that NRDC v. Thomas, 838 F.2d 1224, 1239 (D.C.
Cir. 1988), supported his contention that the support structure is a
nearby structure and is subject to modeling under EPA's stack height
regulations.
Response: The commenter cites language from the opinion that merely
notes that the stack height regulations provide for fluid modeling
demonstrations for sources with porous structures or buildings whose
shapes are aerodynamically smoother than the simple structures on which
the formulae were based. The language cited, and the provisions of 40
CFR 51.100(kk)(3), are not relevant to this issue. As we have already
discussed, the support structure may not be used to calculate formula
height for two reasons--the support structure is part of the stack to
which the formula may not be applied, and the support structure is a
very tall thin structure to which the formula may not be applied. Thus,
it does not matter that the support structure is a cylinder; the
support structure does not fit within the umbrella of 40 CFR
51.100(kk)(3).
(k) Comment: Several commenters (MSCC letter, document # IV.A-19,
comment # 38; MSCC letter, document # IV.A-20, comment #'s 2.B, 2.C,
2.R, 2.U; Goetz letter, document # IV.A-18, exhibit D, p. 36; CPP
letter, document # IV.A-18, exhibit A, p. 5 and Attachment I) stated
that EPA's remedy to address structures that might not lead to accurate
formula height determinations, was to allow for or require fluid
modeling demonstrations. One commenter (MSCC) stated that even if a
source built a stack with the intent of creating excessive formula
height, the source would have no assurance that a fluid modeling
demonstration would justify the height as GEP. The same commenter
stated that, having established fluid modeling as the test where the
formula is questioned, EPA cannot argue that the rules or the Act
require it to disapprove formula height actually demonstrated by fluid
modeling.
Response: We have already explained why the stack support structure
may not be used to calculate the formula. The potential safeguard that
an agency might insist on fluid modeling to challenge the formula
height credit does not render the initial proposition acceptable.
Neither Congress nor EPA intended a stack or part of the stack to be
eligible for consideration in determining formula height. In addition,
we note that a fluid modeling demonstration to justify formula height
is not a cure for applying the formula to a stack or a structure that
is not nearby. This is because the criteria for fluid modeling for
within-formula stack height credit are not as stringent as the criteria
for above-formula stacks. See 40 CFR 51.100(kk)(2) and (kk)(3) versus
subsection (kk)(1). Put another way, the commenters' approach would
turn every fluid modeling demonstration into a within-formula
demonstration, which is
[[Page 22227]]
clearly not what we intended. We also note that these comments ignore
the statement in the Technical Support Document for our stack height
regulations that structures like stacks and radio or TV transmission
towers should not be considered in GEP stack height determinations.
(l) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 2.R) stated that because EPA has argued the Act does not
require it to impose control-first, EPA should conclude that it need
not disapprove the use of tall thin structures or even stacks in
calculating formula heights because the rules and the Act do not
require it do so.
Response: We do not understand the logic of this comment. We
believe our interpretation of the Act and the regulations is reasonable
and best effectuates the purpose behind section 123. Among other
things, we do not believe section 123 allows formula calculations to be
based on the stack; as explained above, section 123 clearly
differentiates between the source and the source's stack. We believe
the commenter's interpretation is unreasonable and would undermine
section 123 and our regulations. We do not believe we have the
discretion to interpret the Act and our regulations in the manner that
the commenter suggests; to the extent we have the discretion to
interpret the Act differently--and to revise our stack heights
regulations accordingly--we have not done so to date.
(m) Comment: Several commenters (MSCC letter, document # IV.A-19,
comment #'s 27, 29, and 90; MSCC letter, document # IV.A-20, comment
#'s 1.E, 2.H; Goetz letter, document # IV.A-18, exhibit D, pp. 12, 33-
34, 36; CPP letter, document # IV.A-18, exhibit A, p. 5) stated that
EPA changed its position on the validity of considering the support
structure in determining formula height and the need to evaluate the
effect of the support structure for purposes of fluid modeling. One
commenter (MSCC) claims that EPA misguided the State and MSCC in the
design of the protocol for the modeling and that the State and MSCC
should not suffer for EPA's change of heart which has no technically
sound basis. This commenter stated that EPA admits that it did not
inform DEQ that the support structure should not be removed in model
runs measuring downwash before the modeling was conducted. The
commenter claimed EPA said it was acceptable to remove the support
structure while the protocol was being written in the fall of 1995. One
commenter (Goetz) stated that EPA's initial response to MSCC's formula
height calculation was reasonable. According to the commenter, EPA
called for verification of the formula height calculation based on the
stack support structure, and EPA has discretion to require such a
verification. This commenter also claimed that, in a letter to the
State, EPA indicated that the support structure could be considered a
nearby structure.
Response: The commenters mis-represent EPA's position regarding the
stack support structure. In our June 27, 1994 letter from Marshall
Payne and Douglas Skie to Jeffrey Chaffee (document # II.F-15), we
unequivocally stated that the formula could not be applied to the MSCC
stack. Although this letter appeared to indicate that fluid modeling of
the support structure could be used to determine GEP credit, at least
three later letters to the State superseded the June 27, 1994 letter on
this point. See our TSD at p. 56; letters dated January 31, 1996, March
15, 1996, and July 18, 1996, document #'s II.F-19, II.F-20, and II.C-
5.)
We agree that we did not inform the State in the fall of 1995 that
the support structure could not be modeled. However, MSCC and DEQ had
ample time to re-run the modeling based on our position and chose not
to do so.
We do not agree that our initial response to MSCC's formula height
calculation (contained in our June 27, 1994 letter, document # II.F-15)
was reasonable. It is contrary to section 123 of the Act and our stack
height regulations to consider part of the stack in calculating formula
height and in performing a wind tunnel study.
(n) Comment: One commenter (CPP letter, document # IV.A-18, exhibit
A, p. 5) asserted that EPA has questioned the use of the formula for
the support structure and required that wind tunnel modeling be
conducted to validate the use of the formula above 65 meters in this
case. Therefore, according to the commenter, wind tunnel tests must be
conducted with and without the support structure present. The commenter
refered to his chronology of events to support his assertion that EPA
required wind tunnel modeling to validate formula height. The commenter
cited EPA guidance and regulations as support for his assertion.
Response: The commenter references a July 27, 1994 letter from
Douglas Skie to Jeffrey Chaffee, but we believe the commenter meant the
June 27, 1994 letter from Marshall Payne and Douglas Skie to Jeffrey
Chaffee (document # II.F-15). The commenter indicates that this letter
said it was acceptable to calculate GEP formula stack height based on
application of the formula to the stack support structure. This is
inaccurate; see our response to the previous comment. Also, as noted in
response to the previous comment, although the June 27, 1994 letter
appeared to indicate that fluid modeling of the support structure could
be used to determine GEP credit, later letters to the State said
otherwise. Despite our admonitions on this matter, the commenter and
MSCC have continued to assert that their within-formula wind tunnel
demonstrations are valid. The commenter also does not mention the fact
that the State did not approve these within-formula stack height
demonstrations. As we have indicated, we believe this fact renders
these demonstrations irrelevant.
The EPA document references cited by the commenter do not support
CPP's approach. The commenter's entire argument rests on the premise
that formula height may be calculated based on the stack support
structure, and that the commenter merely performed wind tunnel tests to
validate formula height. Elsewhere in this document we have described
in detail why the stack support structure may not be used to calculate
formula height. If, as we interpret section 123 of the Act and our
stack height regulations, the stack support structure may not be relied
on to calculate formula height of 98.15 meters, then the commenter has
no valid basis to ``verify'' a formula height of 98.15 meters. As we
have stated, 40 CFR 51.100(kk)(3) is not applicable to MSCC's stack
height determination.
(o) Comment: One commenter (CPP letter, document # IV.A-18, exhibit
A, Attachment I) stated that EPA's objection to the modeling of the
effect of the stack support structure is contrary to all prior
practice. The commenter indicated that CPP has conducted well over 20
GEP stack height evaluations using fluid modeling, most of which have
been approved by EPA, and in every case, CPP has considered the effect
of all nearby structures on downwash. According to the commenter,
``requiring the exclusion of any particular real structure that the
source believes may be contributing to downwash is improper since it
may affect the final result and lead to an improperly low GEP credit.''
The commenter suggested that it is particularly improper when guidance
and the agency indicated downwash from the support structure should be
modeled. The commenter also stated that no purpose would be served by
re-running the test with the structure ``in'' in both cases because
agency guidance indicates the effects of such a tall thin structure are
very small.
[[Page 22228]]
Response: We agree with the commenter that downwash from all nearby
structures should be modeled in a fluid modeling demonstration.
However, as discussed elsewhere, we do not think a component of the
stack--in this case, the stack support structure--may be considered a
nearby structure under the Act or our regulations. The commenter has
not suggested that his past practice has included conducting fluid
model runs with the stack ``in'' and ``out''--i.e., that he has modeled
downwash created by the stack itself. Nor has he cited to any
particular experience that involved modeling a stack support structure.
We disagree with the commenter that the criterion for determining
whether a particular structure should be excluded from fluid modeling
is whether the source believes the structure may be contributing to
downwash. For example, it would be inappropriate to model downwash from
a structure that is more than half a mile from the stack. See 40 CFR
51.100(jj)(2). As we have noted with respect to other comments, this
commenter on the one hand seems to be suggesting that not considering
downwash from the support structure might lead to improperly low GEP
credit, but on the other hand that any downwash from the support
structure is very, very small and that EPA is being unreasonable in
saying the wind tunnel tests should have been re-run. Any other issues
raised in this comment are addressed in our responses to other
comments.
(p) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, p. 12) stated that MSCC's contractor properly ran EPA's own
Building Profile Input Program, and carefully followed the statute's
and rule's stack height formula, to determine a formula height of 98.15
meters for MSCC's stack. According to the commenter, this formula
height was based on the dimensions of the stack support structure.
Response: A computer program is merely a computer program; someone
using it could input any structure dimensions they want and the program
would spit out a result. For example, one could input the dimensions of
a structure more than 5L from the stack, which is not permitted by our
regulations. Use of a computer program does not guarantee a valid
formula height calculation or compliance with the statute and the
regulations.
(q) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 2.J) stated that EPA's own computer program used for
estimating downwash parameters for inclusion in dispersion models
excludes no large structure based on its height to width ratio or
shape. The commenter asserted that two stacks adjacent to each other
may be used as downwash influences on each other.
Response: We have interpreted the statute and regulations that
apply to GEP stack height determinations, and believe they prohibit the
use of the stack or part of the stack to calculate GEP stack height
credit, either through application of the formula or through fluid
modeling. Our rules and guidance for dispersion modeling may be
different, but we do not think this has relevance to our interpretation
of section 123 of the Act and the stack height regulations. Presumably,
dispersion modeling would not exclude a structure more distant than a
half mile either, as long as the structure is within the modeling
domain, but this does not mean that such structure should be considered
nearby for purposes of determining GEP stack height credit.
(r) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, pp. 20--21, 28) quoted from a phone summary prepared by Dr.
Petersen, MSCC's consultant for the fluid modeling study, in which Dr.
Petersen reported on a conversation he had with John Coefield, the
State's modeler, on March 28, 1996. According to Dr. Petersen, Mr.
Coefield indicated that although EPA had raised concerns regarding the
treatment of the stack support structure in the fluid modeling, EPA did
not feel this was a major concern because they felt the structure has a
minor effect anyhow. In addition, the commenter asserted that EPA's
objection to use of the support structure is trivial, and that not one
expert, including EPA's meteorologist, believed that the support
structure in or out will make any difference. Therefore, the commenter
argued that EPA should not use this as a justification to disapprove
the SIP. The commenter quoted from another phone summary prepared by
MSCC's consultant as support for this notion. Another commenter (MSCC
letter, document # IV.A-19, comment # 90) characterized our concern as
a minor technical objection.
Response: Our official communications with the State on this
subject make clear that the treatment of the stack support structure
was not a minor concern. We took the trouble to mention our concern in
three different letters, something we would not have done if this was
merely a minor concern. (See letters dated January 31, 1996, March 15,
1996, and July 18, 1996, document #'s II.F-19, II.F-20, and II.C-5.)
Even Dr. Petersen's notes reflect our meteorologist's belief that
additional testing would be necessary. (See document # IV.A-18, MSCC
Exhibit 144.)
Whether the effect of the support structure on downwash is trivial
or not can be shown through a properly conducted fluid modeling
demonstration. We believe it is reasonable to insist that the
demonstration be properly performed, and this means not modeling
downwash from the support structure that is part of the stack.
We note that one of the commenters (Goetz, document # IV.A-18,
exhibit D, pp. 28, 34-35) argues that the effect of the support
structure is trivial in the fluid model demonstration, but should be
considered in calculating formula height. The commenter asserts that
our Guideline recognizes that even a lattice structure may cause
downwash and suggests that the support structure is more likely to be a
source of downwash because it is an ``enclosed'' structure. It appears
that the commenter's positions regarding potential downwash from the
support structure are inconsistent--the commenter argues that the
downwash impact of the support structure is trivial when commenting on
our objection to the use of the support structure in the wind tunnel
study, but then argues the same downwash impact is important when
arguing that the support structure should be used to calculate formula
height. We do not know the extent of the downwash impact of the support
structure, but our position is consistent--the support structure should
not be used to calculate formula height, and its downwash impacts
should not be considered in a wind tunnel study. The basis for our
position is the same in both cases--the stack cannot be used to justify
itself.
We also note that MSCC has been insistent that it has a right to
model downwash from the support structure, and Larry Zink of MSCC
offered the following testimony in the State hearing:
Yes, we did contract to have the structure built. It's there.
It's real. It causes downwash.
and
When the YELP buildings more fully line up with MSCC's stack and
the wind, this effect becomes larger as it synergizes with the
effects of the support structure, etc.
See ``Rebuttal Testimony of Larry Zink, Vice President of Montana
Sulphur & Chemical Company,'' document # IV.A-17, MSCC Exhibit 127, at
pp. 16, 24. In addition, Larry Zink of MSCC wrote the following in an
August 10, 1994 letter to Jeffrey Chaffee of the State:
[[Page 22229]]
``Common sense'' also certainly does not support the idea that a
thin structure, even an ``aerodynamic'' one, does not generate
substantial and lasting ``downwash,'' ``eddies'' or ``wakes.'' To
the contrary, we know that long and ``thin'' structures, such as
slow-moving aircraft wings, can generate sufficient downwash
turbulence and vortices to slam a distant * * *, following, powered
aircraft to the ground from hundreds of meters in the air. ``Common
sense'' tells us, therefore, that it is probable that a far larger,
less aerodynamic, ground-mounted structure will also produce
significant and lasting downwash, wakes, vortices, and eddies
capable of entraining drifting gases and bringing them prematurely
to ground.
See cited letter, at pp. 12, 13, part of document # II.B-10. It is
difficult to understand how MSCC and its consultants can now
characterize our concern that MSCC improperly modeled downwash from the
support structure as a minor technical objection or trivial. The only
way to properly resolve this issue is to re-do fluid modeling including
the support structure in all model runs--that is, not model downwash
created by the stack support structure. Again, this is because the
stack support structure is part of the stack.
(s) Comment: One commenter (State letter, document # IV.A-23, p.
11, footnote 10, p. 15, footnote 15) agreed with EPA that the stack
support structure should not be considered a ``nearby structure'' for
purposes of the fluid modeling demonstration. However, the commenter
asserted that the impact of evaluating the support structure as a
nearby structure is small. Specifically, the commenter stated, ``the
State's analysis indicated that the FMD (fluid modeling demonstration)
results would not be significantly affected by MSCC's approach, and the
State concluded that requiring MSCC to conduct another demonstration
was not justified.''
Response: It is significant that the commenter is the State, which
is admitting that the fluid modeling demonstration was not conducted
entirely properly. It appears that the State is advancing a de minimis
theory of error, but despite its claims that the impact of the error is
insignificant, the State provides no support for its assertion that the
fluid modeling demonstration would not have changed if MSCC had
properly treated the support structure in the fluid modeling
demonstration.
(t) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 29) stated that either the support structure is a nearby
structure, in which case it should be used to calculate formula height,
or it is not, in which case its inclusion or removal from the fluid
model is obviously irrelevant.
Response: We have already explained our position that the support
structure is not a nearby structure. The commenter's suggestion that if
the support structure is not a nearby structure, it is irrelevant
whether it is included or removed from the fluid model, defies logic.
MSCC has attempted to use the support structure to justify greater GEP
stack height credit, despite the fact that it is not a structure that
may be used for this purpose.
(u) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 31) stated that EPA's treatment of the support structure as
part of the stack somehow violates the provision that the Administrator
cannot prohibit the construction or operation of a stack of any height
by a source.
Response: MSCC remains free to keep its 100-meter stack or build a
taller stack if it wishes. Nothing we are doing in this rulemaking
restricts the actual stack height at MSCC.
5. Issues Related to Other Demonstrations
MSCC and its consultants performed various analyses and asserted
various theories in an attempt to justify 100 meter, or near-100 meter,
stack height credit for MSCC's SRU 100-meter stack. The State only
approved one of MSCC's stack height demonstrations, for 97.5 meters of
credit based on above-formula fluid modeling. We have already described
our basis for concluding that the State-approved stack height credit of
97.5 meters is not valid under the Act and our regulations. Regarding
MSCC's other bases for claiming 100 meter or near-100 meter stack
height credit, we took the position that because the State had not
adopted any of these other bases in determining stack height credit for
the SRU 100-meter stack, these other bases were not before us as part
of this SIP action, and were not relevant to our proposal. Some of
these other bases rely on formula credit for the stack support
structure, which we address in greater detail in the previous section.
We received numerous comments regarding our position regarding
these other bases, mostly from MSCC and its consultants arguing that
these other bases are valid and that we should consider them. Although
we believe these comments are irrelevant to our action, we respond to
them here. Nothing in the comments has caused us to change our position
regarding our disapproval of MSCC's stack height credit.
(a) Comment: One commenter (MSCC letter, document # IV.A-19, #'s
17, 19, 38, 115; MSCC letter, document # IV.A-20, # 1.A) stated that
EPA's proposed disapproval of stack height credit for MSCC violates the
definition of GEP provided in EPA's own rules, which allegedly do not
permit EPA to overrule a State's GEP determination unless the result
would be a higher GEP height. The commenter asserted that EPA delegated
to the states unilateral decisionmaking authority regarding GEP
determinations, but also asserted that EPA may approve a fluid modeling
based GEP determination if the state does not. In any event, in the
commenter's view a state may not disapprove an EPA determination and
EPA may not disapprove a state determination; the exception is in the
event that one regulatory body approves a higher GEP stack height
credit, in which case this higher credit would prevail. The commenter
suggested that new formal federal rule making or new federal
legislation would be needed to change this scheme.
Response: We do not read our regulations to provide carte blanche
to states to make GEP determinations that are inconsistent with the
requirements of Clean Air Act section 123 and our stack height
regulations. We are not bound to accept the greatest of several GEP
heights where that greatest value is not valid under our regulations.
The commenter's position would lead to absurd results: a state could
ignore our regulations in establishing stack height credit, and EPA and
the public would have no recourse. We believe Congress empowered us to
make sure SIP limits are set consistently with the Act's requirements.
Section 110(k)(3) of the Act indicates we can approve the plan if it
meets all of the applicable requirements of the Act and disapprove
parts of the plan if it does not. Also, section 110(l) of the Act
indicates we shall not approve a revision of a plan if the revision
will interfere with any provisions of the Act. Also, there is nothing
in the regulations that suggests our review is a one-way ratchet as the
commenter suggests--that we may only disapprove a state's GEP stack
height credit determination if doing so would result in a higher GEP
stack height.
(b) Comment: One commenter (MSCC letter, document # IV.A-19, p. 2,
and comment #s 28, 35, and 116; MSCC letter, document # IV.A-20,
comment #s 1.F, 1.K, and 2) stated that, in addition to the fluid
modeling approved by the State, MSCC also submitted fluid modeling
demonstrations based on formula height and performed in accordance with
our own rules and guidance. The commenter urged EPA to consider these
demonstrations or
[[Page 22230]]
justifications that allegedly support GEP stack height above 65 meters
for MSCC's main stack. The commenter said that these demonstrations
confirm that GEP is greater than the height credited by the State. The
commenter said that EPA's sole basis for ignoring these other
demonstrations is that the State did not consider them. The commenter
claimed that this is not true, that the State received these
demonstrations and that they should be part of the record. The
commenter seemed to acknowledge that the State did not base its SIP
decisions on these alternative demonstrations, and claimed that the
State misapplied the stack height rules in rejecting these alternative
demonstrations. The commenter claimed that EPA is guilty of
circumventing its own rules in not applying or accepting these
alternative stack height demonstrations that the State rejected. The
commenter asserted that EPA has the discretion to approve these
alternative demonstrations. The commenter argued that if EPA does not
have the authority to approve higher GEP based on alternative
demonstrations, then EPA lacks the authority to overturn the State's
approved determination. The commenter suggested that EPA is only
interested in ``unreasonably preventing one small source in Montana
from obtaining the GEP credit'' to which it is clearly entitled.
Response: We take the SIP as it is submitted to us. The State
rejected MSCC's alternative demonstrations. See our TSD at p. 53.
Therefore, we do not believe those alternative demonstrations are
before us for consideration as part of the submitted SIP, and we do not
believe the CAA requires us to consider alleged justifications for SIP
limits that the State has not adopted or put forward. Also, we do not
believe the presence or absence of authority to consider alternative
demonstrations the State did not endorse has any bearing on our
authority to disapprove emission limits for MSCC that rely on an
improper GEP demonstration. We have clear authority to implement
section 123 of the Act and our stack height regulations and to
disapprove SIP submittals that do not meet the requirements of section
123 of the Act and our stack height regulations.
Even if it would be appropriate for us to substitute an alternative
justification for one put forward by the State, we could not adopt the
position taken by the commenter because that position is inconsistent
with our regulations. We have no vendetta against MSCC as the commenter
suggests. We would very much like to resolve this dispute regarding
stack height credit, but are not willing to do so in a way that is
inconsistent with section 123 of the Act and our stack height
regulations. We have a responsibility to properly apply the stack
height regulations. We believe that the State properly concluded that
the buildings MSCC asserted were nearby for purposes of determining
formula height were in fact not within the distance defined as nearby
by our regulations. Because MSCC could not rely on these buildings or
the stack support structure to determine formula height, MSCC's only
way to justify stack height credit greater than 65 meters was to
perform above-formula fluid modeling pursuant to 40 CFR 51.100(kk)(1).
(c) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 87) stated that the State did not reject other GEP stack
height theories asserted by MSCC, but instead rendered them moot by
entering into a settlement with MSCC over GEP stack height credit based
on a fluid modeling demonstration. According to the commenter, MSCC
reserved all arguments regarding its other demonstrations, as well as
regarding the prior determination of GEP being 100 meters. The
commenter asserted that EPA must consider these other arguments and the
prior determination, and must substitute its judgment for the State's
if EPA finds any of the alternative theories acceptable.
Response: State staff rejected other GEP stack height theories
asserted by MSCC, and the MBER did not adopt any of MSCC's other
theories. Thus, the State did not forward other stack height
determinations to us for consideration, and, as discussed above, we do
not believe it is necessary or appropriate for us to consider or adopt
an interpretation that MSCC did not persuade the State to submit to
EPA. States submit SIPs for EPA approval, not sources. Our duty under
the CAA is to consider the SIP the State has submitted, not an
alternative SIP that one company or individual proposes, but that has
no legitimacy under State law.
Assuming for the moment we have some duty to evaluate alternative
demonstrations that the State has not adopted, we find MSCC's
alternative demonstrations unconvincing. The bases for our findings are
described herein and in the letters cited in our TSD, at page 53. These
letters are contained in the docket for this action.
(d) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 2.T) stated that EPA has inadequately explained the legal and
technical basis for its refusal to consider or approve the alternative
demonstrations, when they clearly demonstrate that GEP is at least 97.5
meters.
Response: We believe our proposal and this notice adequately
explain the basis for our refusal to consider or approve the
alternative demonstrations. We note that the commenter and the attorney
for MSCC make inconsistent arguments: on the one hand they argue that
we may not interfere with the primacy of the State in establishing
emission limits for the seven sources in the Billings/Laurel area and
on the other hand argue that we should consider ``alternative
demonstrations'' that the State did not approve or use to establish
MSCC's emission limits. We are acting on the SIP the State submitted to
us, since only the State has the authority to submit a SIP. In any
event, we explain in detail why we would reject MSCC's alternative
demonstrations if they were before us.
(e) Comment: Another commenter (CPP letter, document # IV.A-18,
exhibit A, p. 7) asserted that EPA should approve at least one of the
five demonstrations CPP performed on behalf of MSCC, and that a single
demonstration is sufficient. This commenter appeared to believe it is
important that all five methods showed similar results to the GEP stack
height credit approved by the State.
Response: For the reasons already stated, we do not believe
alternative demonstrations are before us for consideration. In any
event, as explained in response to other comments, we do not believe
the other demonstrations performed by CPP on MSCC's behalf are valid.
We believe it is irrelevant that all five methods showed similar
results to the GEP stack height credit approved by the State. CPP may
have run the wind tunnel tests consistently; this does not mean the
demonstrations are legally valid.
(f) Comment: One commenter (MSCC letter, document # IV.A-19,
comment # 40; MSCC letter, document # IV.A-20, comment # 2.K) stated
that EPA should consider a fluid modeling demonstration to demonstrate
the validity of formula height for MSCC. The commenter appeared to be
arguing that EPA could either consider the BGI building and ExxonMobil
tank farm to be nearby for purposes of calculating formula height, or
could consider the support structure to be a nearby structure for
purposes of calculating formula height. In either case, according to
the commenter, MSCC has performed fluid modeling that has verified the
validity of formula height. The commenter referred to EPA's definition
of ``nearby'' for purposes of formula determinations as a ``rule of
thumb.''
[[Page 22231]]
Similar comments are contained in CPP's comments (CPP letter, document
# IV.A-18, exhibit A, Attachment I).
Response: MSCC believes it should be able to avail itself of the
provisions of 40 CFR 51.100(kk)(2) for verifying formula stack height
credit. Unlike 40 CFR 51.100(kk)(1), subsection (kk)(2) does not
require that a source meet an NSPS or alternative limit, but instead
allows the source to use the emission rate specified by the applicable
SIP. In MSCC's case, the applicable SIP emission rate is higher and
makes it easier to justify a higher stack height credit. In addition,
MSCC would not be bound to meet an NSPS limit on an ongoing basis.
As a preliminary matter, we note that the State did not adopt this
approach in determining GEP stack height for MSCC. Thus, as noted
previously, we do not believe this basis is before us for
consideration.
Furthermore, to qualify to use the provisions of subsection
(kk)(2), MSCC must be seeking a within formula increase. It is not, and
therefore, cannot avail itself of subsection (kk)(2). First, our
definition of ``nearby'' is not a ``rule of thumb.'' We are not free to
consider sources ``nearby'' that fall outside the 5L distance defined
as nearby by the regulations. Therefore, the BGI building and
ExxonMobil tank farm dimensions cannot be plugged into the formula to
determine formula height. Second, as already discussed at length, we do
not consider the stack support structure to be a nearby structure.
Thus, it cannot be plugged into the formula to determine formula
height.
The further suggestion by CPP that, ``by definition,'' the formula
does not adequately represent the downwash created by the BGI
structure, and therefore, it is appropriate to ``verify'' the formula
with a wind tunnel test under subsection (kk)(3), represents a complete
mis-reading of the stack height regulations. The stack height
regulations make perfectly clear that formula height may only be
calculated based on structures that are within a distance of 5L of the
stack, where L is the lesser of the height or width of the structure.
See 40 CFR 51.100(jj)(1). If a structure is not within 5L of the stack,
it may not be used to calculate formula height of the stack, and there
is no formula height derived from such structure that can be verified
under subsection (kk)(3) or (kk)(2). It is irrelevant that a distance
greater than 5L may be considered ``nearby'' for purposes of a fluid
modeling demonstration under 40 CFR 51.100(jj)(2). This fact does not
validate the use of a within-formula fluid modeling demonstration.
Contrary to the commenter's assertion, we are not interpreting the
subsection (jj)(1) definition of ``nearby'' (for determining formula
height) so as to override the subsection (jj)(2) definition of nearby
(for fluid modeling). We are giving each independent effect as they are
written. It is the commenter who is interpreting subsection (jj)(2) as
trumping subsection (jj)(1), and in so doing, is ignoring the fact that
our regulations require a different type of fluid modeling study to
justify above-formula stack height credit. Our ``simplistic
interpretation,'' which the commenter derides, is the law on this
point.
(g) Comment: One commenter (CPP letter, document # IV.A-18, exhibit
A, Attachment I), relying on language from the preamble to the stack
height regulations to the effect that the formula may not adequately
represent all structures, argued that this necessarily means 40 CFR
51.100(kk)(3) should be used to define the parameters of a fluid
modeling study whenever there may be a question about the application
of the formula in a given situation. The commenter asserted that the
stack height regulations must be interpreted consistent with their
intent, and part of this intent is to ensure that a ``stack is built
and credited tall enough to avoid this adverse downwash effect.''
Response: We disagree with the commenter. As we have stated
elsewhere, subsections (kk)(2) and (kk)(3) of 40 CFR 51.100 only apply
to within-formula fluid modeling demonstrations. They are used to
determine whether a source should receive full credit for a formula
height determination. As a starting point, a formula height must first
be calculated in accordance with 40 CFR 51.100(ii)(2), and this formula
height then becomes the upper bound for any fluid modeling
demonstration under subsection (kk)(2) or (kk)(3). In our view, a
formula height that is not calculated in accordance with 40 CFR
51.100(ii)(2) is not a formula height at all; in this situation, there
is no formula height to be verified and one never reaches fluid
modeling under subsection (kk)(2) or (kk)(3). As we describe in detail
elsewhere, we do not believe formula height for MSCC's stack under 40
CFR 51.100(ii)(2) may be calculated based on the BGI structure or the
stack support structure. Neither is a nearby structure under 40 CFR
51.100(jj)(1). It is only when the accuracy of the formula for a nearby
structure is questioned that subsection (kk)(2) or (kk)(3) apply. We
describe elsewhere when each applies.
The commenter mis-reads the intent of the stack height regulations.
The stack height regulations are intended to ensure that inappropriate
dispersion is not used in lieu of emissions controls. Generally
speaking, the regulations restrict stack height credit to the minimum
needed to avoid excessive concentrations. And, the regulations do not
require or ensure that stacks of any particular height be built. After
all, dispersion is only one means to address ground level
concentrations of pollutants. Thus, we do not believe granting greater
stack height credit is a goal of the regulations, and we do not believe
the commenter's interpretation of our regulations is consistent with
the intent of the regulations or the Act.
(h) Comment: One commenter (CPP letter, document # IV.A-18, exhibit
A, Attachment I) stated his understanding that EPA waives the
demonstration requirement under 40 CFR 51.100(kk)(2) for existing
sources where new structures have been built after the original stack
was designed (referring to the BGI structure, the stack support
structure, tankage and buildings) that may reasonably be expected to
produce additional downwash effects.
Response: Our policy provides that it will generally be reasonable
for a source seeking credit for additional stack height to recalculate
its good engineering practice formula height due to the siting of a
new, nearby structure, without the need to justify the increase through
fluid modeling under subsection (kk)(2). See June 29, 1992 memorandum
for John Calcagni entitled ``Credit for Stack Height Increases Due to
the Siting of New, Nearby Structures,'' document # IV.C-76. As we
already indicated, we do not consider either the BGI structure or the
stack support structure to be nearby structures as defined in our
regulations. Thus, they may not be used to calculate formula height,
and within formula fluid modeling demonstrations are not appropriate.
We are not sure what tanks and buildings the commenter is referring to,
but to our knowledge, neither MSCC nor the State have calculated a
formula height for MSCC greater than 65 meters based on tanks or other
buildings.
(i) Comment: One commenter (CPP letter, document # IV.A-18, exhibit
A, Attachment I) stated that this is one of the most extensively
evaluated GEP stack heights he is aware of in his professional career,
which spans over 20 years.
Response: We do not doubt the amount of effort CPP put into their
evaluation. However, we strongly disagree with the commenter's
interpretation of the stack height regulations. Under current
conditions, we cannot approve stack height credit
[[Page 22232]]
for MSCC greater than 65 meters. The commenter's hypothetical about one
stack A outside 5L and another stack B within 5L receiving different
stack height credit is not convincing. Again, this is a result of the
way the stack height regulations are written. If stack A is only built
to 65 meters, and is modeled at 65 meters in an attainment
demonstration, the assertion that NAAQS exceedances are likely to occur
due to downwash ``fictitiously ignored'' is inaccurate. The modeling
for the attainment demonstration using the actual height of the stack
should ensure that NAAQS exceedances due to downwash or any other
condition do not occur. If Stack A is built to 100 meters but only
receives credit for 65 meters, dispersion modeling of the 65 meter
stack height credit will, in a sense, over-predict the impact of Stack
A emissions, and Stack A will have to control emissions as if it were a
65 meter stack. However, this is exactly what the stack height
regulations require if 65 meter credit is all that's warranted under
the regulations.
(j) Comment: One commenter (MSCC letter, document # IV.A-20,
comment # 2.D) stated that BGI should be considered a nearby structure
for determining formula height for the MSCC stack. The commenter
claimed that guidance assumptions artificially restrict the height
calculations for the BGI structure; that the true height of the BGI
structure is much taller than the artificially restricted height
calculations. According to the commenter, using the true height of the
BGI structure in the 5L formula specified in the regulations would make
the BGI structure nearby for purposes of determining formula height.
Response: The State rejected MSCC's arguments that BGI is a nearby
structure for purposes of determining formula height. Because the State
did not adopt MSCC's position in calculating GEP stack height credit
for MSCC, we do not believe this proposition is before us in this
rulemaking. Assuming for the sake of argument that we need to consider
this alternative theory, MSCC has not provided information to support
its assertion that the BGI is within 5L of the MSCC stack. Our
information indicates that BGI is not within 5L of the MSCC stack.
(k) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, pp. 31, 32) stated that MSCC's nuisance studies support a
formula stack of 98.15 meters.
Response: The State did not approve GEP stack height credit for
MSCC based on MSCC's nuisance studies. Because the State did not adopt
this position in calculating GEP stack height credit for MSCC, we do
not believe this proposition is before us in this rulemaking. However,
assuming for the sake of argument that we have an obligation to
consider this potential justification, we disagree with the commenter.
Section 51.100(kk)(2) only applies for sources raising stacks below
formula height up to formula height. The commenter assumes formula
height is 98.15 meters. However, this is based on the stack support
structure. As explained in our proposal and elsewhere in this document,
the stack support structure may not be used to calculate formula height
because it is part of the stack itself. Furthermore, under section
51.100(kk)(2), MSCC could only increase its stack height credit to the
formula height calculated based on nearby structures that existed as of
the time the nuisance was present--in other words, before the stack was
raised.\29\ See 50 FR 27899, 27901. In MSCC's case, this was less than
the de minimis height of 65 meters, so a nuisance showing would provide
no benefit. We have previously indicated that MSCC may receive credit
for stack height up to 65 meters without a demonstration.
---------------------------------------------------------------------------
\29\ MSSCC claimed that its pre-existing 30 meter stack resulted
in a nuisance and asserted that the drastic reduction in citizen
complaints after the erection of the 100-meter stack demonstrated
the existence of a nuisance before the 100-meter stack was erected.
see Goetz letter, document # IV.A-18, exhibit D, at p. 32.
---------------------------------------------------------------------------
(l) Comment: Two commenters (CPP letter, document # IV.A-18,
exhibit A, p. 5 and Attachment I; Goetz letter, document # IV.A-18,
exhibit D, pp. 13--15) stated that 40 CFR 51.100(kk)(3) is the most
appropriate method for determining GEP stack height credit for MSCC's
SRU 100-meter stack and it does not require any presumed rate of
emissions. One of the commenters (Goetz) asserted that Dr. Petersen's
(MSCC's consultant) wind tunnel study verified GEP stack height at
98.15 meters under subsection (kk)(3) and that neither EPA nor the
State had conducted a wind tunnel study to refute Dr. Petersen's
findings.
Response: As an initial matter, we do not believe this comment is
relevant to our action because the State did not adopt or approve the
within-formula approach. Nevertheless, we respond to the comment. Once
again, the stack support structure may not be used to establish formula
height, and thus, of necessity, for any heights above 65 meters, MSCC
is seeking above-formula stack height credit. Because MSCC is seeking
above-formula stack height credit, subsection kk(3) is not applicable.
See 50 FR 27900--27901, July 8, 1985. Even if MSCC were seeking within-
formula stack height credit, subsection (kk)(3) would not apply to
MSCC's fluid modeling demonstration because subsection (kk)(2) applies
when a source seeks credit after October 11, 1983 for increasing
existing stack height. Id. at 27899--27901; NRDC v. Thomas, 838 F.2d
1224, 1239--1240. MSCC had an existing stack before October 11, 1983,
and is seeking credit after October 11, 1983 for increasing the
existing stack height. The provisions of 40 CFR 51.100(kk)(3) only
apply to new construction. 50 FR 27900--27901; NRDC v. Thomas, 838 F.2d
1224, 1239--1240, 1247. Thus, the categories under subsection (kk) are
mutually exclusive and hierarchical. It becomes progressively easier to
justify stack height credit as one moves from subsection (kk)(1) to
subsection (kk)(3). If subsection (kk)(1) applies, a source may not use
subsection (kk)(2) or subsection (kk)(3). If subsection (kk)(2)
applies, a source may not use subsection (kk)(3).
Therefore, Dr. Petersen's wind tunnel study did not properly verify
GEP stack height at 98.15 meters based on subsection (kk)(3), and there
was no need for EPA or the State to conduct a wind tunnel study to
refute Dr. Petersen's findings. Legally, those findings are not
supportable.
(m) Comment: One commenter (CPP letter, document # IV.A-18, exhibit
A, Attachment I) stated that ``[i]t has been argued that any height can
be justified as GEP based on the 40% test, but as those knowledgeable
in the field know, this is not true.'' The commenter suggested that
subsection (kk)(3)'s requirement for a showing of a 40% increase in
downwash in the wind tunnel test will constrain the amount of stack
height credit that will be granted to a rounded structure like a stack.
Response: We are not sure the commenter is suggesting this, but we
want to clarify that we have not taken the position that any height can
be justified in the wind tunnel based on the 40% test of excessive
concentrations. We recognize that the 40% test will act as a constraint
on GEP stack height credit in certain situations, depending on the
dimensions of nearby structures and wind conditions. This should be
distinguished from our position regarding the use of stack dimensions
to calculate GEP formula height. Because formula height equals one
times the height of the structure plus one and a half times the lesser
of the height or width of the structure, application of the formula to
stack dimensions will always result in
[[Page 22233]]
formula height slightly higher than the stack. We reiterate that
application of the formula in this manner amounts to a stack justifying
itself.
As indicated in response to the previous comment, because we do not
believe the GEP formula may be applied to the stack support structure
in the first instance, we do not believe MSCC may avail itself of the
provisions of subsection (kk)(3) or (kk)(2) of 40 CFR 51.100, which are
clearly less stringent than the requirements of 40 CFR 51.100(kk)(1).
(n) Comment: One commenter (CPP letter, document # IV.A-18, exhibit
A, p. 5) stated that MSCC's contractor and others have conducted a
number of GEP stack height demonstrations in complex terrain where a
GEP stack height significantly taller than formula height has been
justified. The commenter cited four examples and concludes that above
formula stack heights are not rare.
Response: The import of this comment is not clear to us. If the
commenter is suggesting that Congress's intent--that above-formula
stack height credit should be rarely granted--has not been achieved in
practice, we do not think this is relevant. It does not change
Congress' intent. Furthermore, four sources, among all the possible
sources within the United States, is not very many. To the extent the
commenter is suggesting MSCC's contractor has expertise from other
cases in conducting above-formula demonstrations, that does not alter
our reading of the statute and the regulations, and our view that
MSCC's various stack height demonstrations are not supportable.
(o) Comment: One commenter (Goetz letter, document # IV.A-18,
exhibit D, pp. 29--31) stated that EPA must evaluate MSCC's air
dispersion study, which allegedly demonstrated excessive
concentrations. According to the commenter, EPA's rejection (for both
ExxonMobil and MSCC) of dispersion modeling for purposes of showing
excessive concentrations is arbitrary and in violation of its modeling
guidelines. The commenter quoted from EPA's guidelines.
Response: The State did not approve GEP stack height credit for
MSCC based on MSCC's air dispersion study. Because the State did not
adopt this position in calculating GEP stack height credit for MSCC, we
do not believe this proposition is relevant to our action. However,
assuming for the sake of argument that we have an obligation to
consider this potential justification, we disagree with the commenter.
The stack height regulations are clear--GEP stack height is defined as
the greater of (1) 65 meters, (2) formula height, or (3) ``the height
demonstrated by a fluid model or a field study * * *'' 40 CFR
51.100(ii). The regulation does not allow for disperson modeling
demonstrations of downwash.
Furthermore, the commenter misinterprets our modeling guideline at
40 CFR part 51, appendix W, section 7.2.5. Section 7.2.5(a) of appendix
W clearly indicates that GEP stack height is defined elsewhere and that
other documents should be followed for determining GEP stack height
credit. Section 7.2.5(b) of appendix W must be read in conjunction with
the remainder of appendix W (section (a) of the Preface to appendix W
is instructive) to understand its application. Section 7.2.5(b) does
not indicate that dispersion modeling may be used to determine downwash
under our stack height regulations; instead, it indicates that
dispersion modeling may be used to calculate cavity and wake effects
for stacks under formula height when a State or EPA is evaluating air
quality impacts and the adequacy of a control strategy in a SIP
revision. This is a different purpose, and, as we noted in our
September 16, 1994 letter from Douglas Skie to Jeffrey Chaffee
(document #IV.A-17, MSCC Exhibit 123), the dispersion model (ISC) is
based on assumptions regarding the existence of downwash for stacks
less than formula height that are not appropriate for a fluid modeling
demonstration.
(p) Comment: One commenter (Goetz letter, document #IV.A-18,
exhibit D, p. 17) stated that EPA's position, that it need not review
the issue of whether MSCC is entitled to formula height of 98.15 meters
because this was not a basis for the approval request submitted by
Montana, is wrong. The commenter cited Bethlehem Steel Corp. v. U.S.
EPA, 782 F.2d 645, 651-652 (7th Cir. 1986). MSCC's alternative
demonstrations must be addressed.
Response: We disagree with the commenter. As we have already
discussed, we do not believe we are obligated to review stack height
demonstrations the State has not endorsed and submitted to us for
approval. We also do not believe the case the commenter has cited
stands for the proposition that we must review theories the State has
not endorsed and submitted to us. In the portion of Bethlehem Steel
Corp. that the commenter cites, EPA disapproved a State regulation that
the State had submitted for approval into the SIP, and the Court held
that EPA's disapproval was reviewable. Unlike in Bethlehem Steel Corp.,
MSCC's alternative demonstrations were neither adopted by the State nor
submitted to us for approval. In the event that a Court decides we are
obligated to consider MSCC's alternative demonstrations, we have
considered all comments related to MSCC's other theories and have
provided our reasons for rejecting those theories.
(r) Comment: Two commenters (MSCC letter, document #IV.A-19,
comment #49; Goetz letter, document #IV.A-18, exhibit D, p. 18,
footnote 9, p. 28) stated that the CPP/Bison fluid modeling analysis
performed for MSCC showed a NAAQS exceedance.