Approval and Promulgation of Implementation Plans; Arizona- Phoenix Nonattainment Area; PM<INF>10

Note: EPA no longer updates this information, but it may be useful as a reference or resource.
 [Federal Register: April 10, 1995 (Volume 60, Number 68)]
[Rules and Regulations]
[Page 18010-18020]
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[AZ31-1-6531; FRL-5173-8]

Approval and Promulgation of Implementation Plans; Arizona-
Phoenix Nonattainment Area; PM10

AGENCY: Environmental Protection Agency (EPA).
ACTION: Final rule.



SUMMARY: EPA is finalizing the approval of a revision to the Arizona
State Implementation Plan (SIP) proposed in the Federal Register on
July 28, 1994. The revision was submitted to EPA by Arizona to fulfill
the State's obligation to revise its SIP to meet the PM10
(particulate matter less than or equal to 10 microns in aerodynamic
diameter) ``moderate'' area planning requirements of the Clean Air Act
(CAA or Act). This approval action will incorporate this revision into
the federally approved SIP. The intended effect of approving this
revision is to regulate emissions of PM10 in the Phoenix Planning
Area (PPA). The revised SIP controls PM10 emissions from sources
including, but not limited to, paved roads, construction and demolition
activities, unpaved parking areas and roads, nonmetallic mineral mining
and processing facilities, open burning activities, uncovered haul
trucks and farming operations. Thus, EPA is finalizing the approval of
this revision into the Arizona SIP under provisions of the CAA
regarding EPA action on SIP submittals, SIPs for national primary and
secondary ambient air quality standards and plan requirements for
nonattainment areas.

EFFECTIVE DATE: This action is effective on May 10, 1995.

ADDRESSES: Copies of the SIP revision are available for public
inspection at EPA's Region IX office during normal business hours.
Copies of the submitted SIP revisions are available for inspection at
the following locations:

Plans Development Section (A-2-2), Air and Toxics Division, U.S.
Environmental Protection Agency, Region IX, 75 Hawthorne Street, San
Francisco, CA 94105.
Environmental Protection Agency, Air Docket (6102), 401 ``M'' Street
SW., Washington, DC 20460.
Arizona Department of Environmental Quality, 3033 North Central Avenue,
Phoenix, AZ 85012.

FOR FURTHER INFORMATION CONTACT: Robert Pallarino, (415) 744-1212.
SUPPLEMENTARY INFORMATION: [[Page 18011]]

I. Background

A. CAA Requirements

    On the date of enactment of the 1990 Clean Air Act Amendments,
PM10 areas, including the PPA, meeting the conditions of section
107(d) of the Act were designated nonattainment by operation of law.
Once an area is designated nonattainment, section 188 of the Act
outlines the process for classification of the area and establishes the
area's attainment date. In accordance with section 188(a), at the time
of designation, all PM10 nonattainment areas were initially
classified as ``moderate'' by operation of law. See 40 CFR 81.303
(1993). A moderate area may subsequently be reclassified as ``serious''
if at any time EPA determines that the area cannot practicably attain
the PM10 NAAQS by the applicable attainment date for moderate
areas, December 31, 1994. Moreover, a moderate area is reclassified by
operation of law if the area is not in attainment after the applicable
attainment date, which is December 31, 1994 for the PPA. EPA is
required to make a determination and provide public notice regarding
whether the area has attained within six months following the
attainment date. See Section 188(b), 42 U.S.C. 7513(a).
    The air quality planning requirements for moderate PM10
nonattainment areas are set out in subparts 1 and 4 of title I of the
Act. EPA has issued guidance in its General Preamble describing EPA's
views on how the Agency will review SIPs and SIP revisions submitted
under title I of the Act, including those containing moderate PM10
nonattainment area SIP provisions. 57 FR 13498 (April 16, 1992); 57 FR
18070 (April 28, 1992). The General Preamble provides a detailed
discussion of the EPA's interpretation of the Title I requirements.
    States with initial moderate PM10 nonattainment areas were
required to submit, among other things, the following provisions by
November 15, 1991:¹

    \1\There are additional submittals associated with moderate
PM10 nonattainment plans, such as a permit program for the
construction of new and modified major stationary sources and
contingency measures. See sections 189(a) and 172(c)(9). These
submittals were required to be submitted in 1992 and 1993,
respectively, and are not the subject of today's action which
addresses only those plan provisions required to be submitted on
November 15, 1991.
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    1. Provisions to assure that reasonably available control measures
(RACM) (including such reductions in emissions from existing sources in
the area as may be obtained through the adoption, at a minimum, of
reasonably available control technology (RACT)) shall be implemented no
later than December 10, 1993;
    2. Either a demonstration (including air quality modeling) that the
plan will provide for attainment as expeditiously as practicable but no
later than December 31, 1994, or a demonstration that attainment by
that date is impracticable;
    3. Pursuant to section 189(c)(1), for plan revisions demonstrating
attainment, quantitative milestones which are to be achieved every 3
years and which demonstrate reasonable further progress (RFP) toward
attainment by December 31, 1994;² and

    \2\As discussed in the Federal Register notice proposing
approval of this plan, the PM10 plan for the PPA does not
demonstrate attainment by December 31, 1994, but rather includes the
alternative demonstration that attainment by that date is
impracticable. Therefore, section 189(c) does not apply. However, as
discussed further in this notice, areas demonstrating that
attainment is impracticable are required by section 172(c)(2) to
demonstrate RFP. See Section IV. of this Notice, ``Reasonable
Further Progress''.
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    4. Provisions to assure that the control requirements applicable to
major stationary sources of PM10 also apply to major stationary
sources of PM10 precursors, except where the Administrator
determines that such sources do not contribute significantly to
PM10 levels which exceed the NAAQS in the area.
    In today's rulemaking action, EPA is taking final action to approve
Arizona's moderate PM10 SIP revision for the PPA, which includes
the State's demonstration that attainment of the PM10 NAAQS by
December 31, 1994, is impracticable for the PPA. EPA is also announcing
its intention to reclassify the PPA as a serious nonattainment area
pursuant to section 188(b)(2). However, EPA is not making a finding as
to whether the PPA has attained the PM10 NAAQS in today's action,
but, as discussed elsewhere in this Notice, will be doing so in a
separate action in the coming months. See Section III. Once EPA
determines the PPA has not attained the PM10 NAAQS, the area will
be reclassified to serious by operation of law.

B. Proposed SIP Approval

    EPA proposed approval of the moderate area PM10 SIP revision
for the PPA on July 28, 1994 (59 FR 38402). EPA's proposed approval was
based on a preliminary finding that the State's submittal meets the
requirements of the Act, including: (1) an inventory of all sources of
PM10 in the nonattainment area; (2) provisions to implement RACM
by December 10, 1993; and (3) a demonstration that attainment of the
PM10 NAAQS by the moderate area attainment date, December 31,
1994, is impracticable.
    EPA proposed simultaneously to approve Maricopa County Rule 310--
Open Fugitive Dust Sources, 311--Particulate Matter from Process
Industries, 314--Open Outdoor Fires, and 316--Nonmetallic Mineral
Mining and Processing, as new rules the State adopted as RACM for the
PPA. EPA also proposed to reclassify the PPA as a serious area and
invited public comment on whether final action should occur under
section 188(b)(1) or 188(b)(2) of the CAA.

II. Today's Action

    In today's document, EPA is taking final action to approve the
moderate area PM10 state implementation plan revision for the PPA.
The SIP revision for the PPA was submitted by the State of Arizona on
August 11, 1993 and March 3, 1994. Maricopa County Rule 314 was adopted
by the State and submitted to EPA on January 4, 1990. The State also
submitted a revised version of Maricopa County Rule 310--Open Fugitive
Dust Sources on December 19, 1994. The County revised this rule to
delete provision 221.9 of the Rule as requested by EPA. See 59 FR
38407, July 28, 1994. Specifically, EPA is approving and incorporating
by reference into the SIP the MAG 1991 Particulate Plan for PM10
for the Maricopa County Area and 1993 Revisions, the Revised Chapter 9
and Maricopa County Rule 311--Particulate Matter from Process
Industries and Rule 316--Nonmetallic Mineral Mining and Processing,
Maricopa County Rule 314--Open Outdoor Fires and Maricopa County Rule
310--Open Fugitive Dust Sources. EPA is also stating its intention, but
is not taking final action at this time, to reclassify the PPA under
section 188(b)(2) of the Act. EPA is not taking final action on its
proposal to reclassify the PPA under section 188(b)(1) of the Act.

III. Reclassification

    As stated above, EPA is not reclassifying the PPA in this document.
However, EPA intends to propose reclassification of the PPA to a
serious area pursuant to section 188(b)(2) of the Act.
    The Act provides two mechanisms for reclassifying moderate
PM10 nonattainment areas as serious PM10 nonattainment areas.
Section 188(b)(1) gives EPA the discretion to reclassify any area which
EPA determines cannot practicably attain the NAAQS by the applicable
attainment date at any time before the attainment date. In the case
[[Page 18012]] of the PPA, the CAA-mandated attainment date was
December 31, 1994. The second mechanism for reclassification, provided
by section 188(b)(2), is to make a finding after the attainment date
has passed that the area has not attained the NAAQS.
    The difference between these two mechanisms involves the timing of
submittals of certain plan provisions. Under section 188(b)(1), if EPA
were to take final action on its proposal to reclassify the PPA as
serious (see 59 FR 38406, July 28, 1994) the State would be required to
submit its serious area SIP revision in two parts. Within 18 months of
the final action reclassifying the PPA, the State would be required to
submit provisions to assure the implementation of best available
control measures (BACM) no later than four years after the date of
reclassification. The State's demonstration that the plan provides for
attainment of the PM10 NAAQS by the serious area attainment date
(December 31, 2001) would have to be submitted within four years of the
date of reclassification.
    Under section 188(b)(2) of the Act, if EPA makes a determination
after the moderate area attainment date has passed that the PPA has not
attained the NAAQS, then within 18 months after the date of
reclassification, the State is required to submit provisions to assure
the implementation of BACM no later than four years after the date of
reclassification and a demonstration that the plan will provide for
attainment of the PM10 NAAQS by December 31, 2001. The practical
difference in these two approaches is the timing of the submittal of
the attainment demonstration and how it affects the BACM determination.
    Under section 188(b)(1), the State would initially develop its BACM
determination in the absence of an attainment demonstration with the
potential result that the chosen measures would not ultimately attain
the PM10 standards by the applicable attainment date. Such a
result, however, would not be revealed until several years later, when
the air quality modeling analysis is conducted for the attainment
demonstration. If, at that point, additional measures were found to be
necessary for the area to attain the PM10 NAAQS, new measures
would have to be developed, adopted and submitted to EPA. In contrast,
under section 188(b)(2), all the required elements of the serious area
plan including the attainment demonstration must be submitted to EPA
within 18 months of reclassification. Thus, under section 188(b)(2),
EPA believes the process of attaining the PM10 standards is
expedited.
    In its notice of proposed rulemaking, EPA expressed its intent to
reclassify the PPA under section 188(b)(2) of the Act. EPA believed
that since the State originally concluded that the PPA could not
practicably attain the PM10 NAAQS by December 31, 1994 when it
developed its November 1991 plan submission and that, despite
procedural delays and plan updates culminating in the 1993 and 1994 SIP
submittals, this conclusion has not changed, the State has been on
notice for more than three years that reclassification was likely.
Under these circumstances, a delay of four years for the submission of
a serious area attainment demonstration is unwarranted. Rather, the
Agency believed that it is more appropriate to accelerate, to the
maximum extent possible, the State's submission of a complete serious
area plan to attain the PM10 NAAQS.
    Notwithstanding the reasons above, EPA stated in its proposed
rulemaking that there could be valid reasons advanced for reclassifying
the PPA under section 188(b)(1). Therefore, EPA proposed to reclassify
the PPA using its discretionary authority under section 188(b)(1). EPA
stated its intent to finalize the reclassification under section
188(b)(1) only if it received compelling arguments from commenters. EPA
received comments on the issue of reclassification from the Arizona
Department of Environmental Quality (ADEQ), Maricopa Association of
Governments (MAG), Maricopa County Environmental Services Department
(MCESD), Arizona Department of Transportation (ADOT), and Arizona
Center for Law in the Public Interest (ACLPI). The comments from ADEQ,
MAG, MCESD, and ADOT all encouraged EPA to reclassify the PPA
immediately under section 188(b)(1). These commenters were concerned
that the State's ability to complete the required technical elements of
the serious area SIP revision, particularly an improved and updated
emission inventory and an accurate air quality analysis including air
quality modeling, would require the longer submittal time for a
demonstration of attainment afforded under section 188(b)(1) of the
Act. Many of the commenters also argued that taking final action to
reclassify the PPA before the moderate area attainment date would
expedite the air quality benefits which would be provided by the
serious area plan since the BACM implementation date would occur
sooner.
    EPA has not been persuaded by these comments to reclassify the PPA
under section 188(b)(1). EPA believes that the State has been aware for
a number of years that, even taking into consideration the
implementation efforts it has now undertaken in complying with the
PM10 Moderate area planning requirements, that it was
impracticable to demonstrate attainment of the PM10 NAAQS by
December 31, 1994. Thus, EPA does not believe the State has provided
any valid basis to delay submittal of an attainment demonstration by
four years. Furthermore, the schedule for developing and submitting the
technical elements of the serious area SIP revision is no different
than the schedule for submitting a complete SIP revision for areas
designated nonattainment after the passage of the 1990 CAA amendments.
Under section 189(a)(2)(B) these areas are required to submit SIP
revisions within 18 months after the date they are redesignated. The
requirements for developing the technical elements of a serious area
SIP are not substantially different from those for a moderate area.
    Regarding the BACM implementation date, the Act simply states that
BACM is to be implemented no later than four years after
reclassification to serious. Under the overall scheme of the Act, the
State is certainly permitted and, in fact, encouraged to implement BACM
on as expeditious a schedule as practicable before the four-year
deadline.
    EPA also notes that ACLPI opposed reclassification of the PPA under
188(b)(1) because it would have the effect of rewarding the State's
delay in preparing its PM10 SIP by giving the State four years
instead of 18 months to submit its serious area plan revision. However,
EPA is not taking final action to reclassify the PPA under section
188(b)(1). For the reasons stated above, EPA believes that
reclassification under section 188(b)(2) is the appropriate action to
take in this case. EPA will be reviewing the PM10 monitoring data
for the PPA and will make an official determination of whether the PPA
has attained the PM10 NAAQS by June 30, 1995 or sooner. To
demonstrate attainment of the PM10 NAAQS by the applicable
attainment date (December 31, 1994), the PPA would need to show that it
has had no violations of the PM10 standards, 24 hour and annual,
in the past three years (1992, 1993, and 1994). 40 CFR part 50,
appendix K. The State recorded violations of both standards in 1992 and
1993.

IV. Reasonable Further Progress

    Section 172(c)(2) of the Act states that nonattainment area plans
shall require [[Page 18013]] reasonable further progress (RFP). RFP is
defined by section 171(1) as ``such annual incremental reductions in
emissions of the relevant air pollutant as are required by this part or
may reasonably be required by [EPA] for the purpose of ensuring
attainment of the applicable [NAAQS] by the applicable date.'' However,
there is a gap in the statute in that the PM10 specific provisions
of the Act do not clearly specify when and in what manner states
containing PM10 nonattainment areas that ultimately demonstrate it
is impracticable to attain the NAAQS by the Moderate area deadline,
such as the PPA, which is the subject of this document, must
demonstrate they have met the RFP requirement. While section 189(c)(1)
of the Act requires PM10 SIP revisions to contain quantitative
milestones which are to be achieved every 3 years until the area is
redesignated attainment and which must also demonstrate reasonable
further progress, that section, by its explicit terms, only applies to
areas with ``plan revisions demonstrating attainment.'' However, while
it appears that the Act does not provide specifically for a
quantitative milestone reporting requirement showing RFP is met for
areas that demonstrate it is impracticable to attain the PM10
NAAQS by the applicable deadline, EPA nonetheless believes, based on
the general nonattainment area provisions regarding RFP as well as the
overall purpose and structure of Title I and Part D of the Act, that
such areas are not thereby relieved of the obligation to periodically
demonstrate that they are meeting the requirement for RFP.
Consequently, for purposes of implementing the RFP requirement for such
areas, EPA believes that where the language in section 171(1) indicates
that the purpose of the RFP reductions is to ensure ``attainment of the
applicable [NAAQS] by the applicable [attainment] date,'' the
applicable attainment date for areas demonstrating that it is
impracticable to attain would be the date set by section 188(c) when
the area is reclassified as serious. Similarly, since the Act does not
explicitly provide for states with PM10 nonattainment areas which
demonstrate it is impracticable to attain to submit periodic reports
demonstrating that RFP is being met, such as is required under section
189(c)(1) for PM10 areas which demonstrate attainment, EPA
believes it may invoke the discretionary authority provided the Agency
under section 110(p) of the Act to require the submittal of such
reports. That section states that ``any State shall submit'' such
reports as EPA may require, and on such schedules as EPA may prescribe,
providing information on specific data but also including ``any other
information [EPA] may deem necessary to assess the development
effectiveness, need for revision, or implementation of any plan or plan
revision required under this Act.'' The initial RFP report for such
areas is to be included in the SIP submittal containing the area's
demonstration of impracticability, and should show that even though the
emissions reductions achieved through the implementation of all RACM
may not be enough to enable the area to demonstrate attainment by the
Moderate area deadline of December 31, 1994, such implementation has
resulted in ``incremental reductions'' in emissions of PM10 as the
RFP definition in section 171(1) specifies. Once the area has been
reclassified, subsequent RFP report submittals will be timed to reflect
emissions reductions which will be achieved due to the implementation
of BACM. In summary then, EPA's policy is that the requirement to
submit periodic reports demonstrating that RFP (as defined in section
171(1)) is being met applies equally to PM10 nonattainment areas
that demonstrate attainment by the applicable deadline and to such
areas that demonstrate it is impracticable to attain by such date; for
the former areas the requirement applies pursuant to sections 189(c)(1)
and 172(c)(2), for the latter areas the requirement applies pursuant to
sections 172(c)(2) and 110(p). As described in greater detail elsewhere
in this document, the Phoenix Planning Area, has provided information
along with its impracticability demonstration, which proves to EPA's
satisfaction that it has met the requirement to demonstrate RFP.
Finally, the discussion in this document regarding the demonstration of
RFP in PM10 nonattainment areas which demonstrate that attainment
by the applicable attainment date is impracticable represents EPA's
preliminary guidance on this issue, and is intended to clarify the
confusion created by omissions in the Act and in prior EPA guidance.
EPA also intends, in the very near future, to issue more comprehensive
guidance on this issue.

V. Response to Comments on Proposed SIP Approval

    Only ACLPI commented on EPA's proposed approval of the SIP
revision; other commenters addressed reclassification. EPA appreciates
the comments submitted by ACLPI, which are detailed and thoughtful.
Some of the comments raise difficult issues regarding the State's
compliance with complex planning requirements, which often depend on
coordination between a number of local governments. ACLPI's most
detailed comments concern the State's implementation of RACM,
particularly Transportation Control Measures (TCMs). In this document,
EPA is providing its general response to ACLPI's comments on the
implementation of RACM, and EPA is also providing very detailed
responses concerning individual TCMs and other specific measures raised
in ACLPI's comments in the Technical Support Document (TSD)
accompanying this document.

A. Technical Issues

1. Monitoring
    Comment: The PM10 SIP revision for the PPA does not provide
for the establishment and operation of a PM10 monitoring network
which meets the requirements of EPA guidelines and regulations.
According to a 1992 EPA audit, the monitoring network for the Phoenix
area ``fails to meet many of the minimum CFR requirements''.
    Response: EPA disagrees with the comment. The PM10 SIP
revision provides for establishing and operating a PM10 monitoring
network in the PPA which meets the requirements of EPA guidelines and
regulations. 40 CFR part 58; ``Guideline for the Implementation of the
Ambient Air Monitoring Regulations 40 CFR Part 58.'' The relevant
provisions of the PPA's monitoring network are in Appendix B, Exhibit
14 of the SIP revision. Appendix B, Exhibit 14 also discusses proposed
modifications to the network and the method by which the Maricopa
County Environmental Services Department (MCESD) will address episode
occurrences.
    Since a 1992 Re-Evaluation of the Maricopa County Air Pollution
Control Program that was conducted by EPA, the MCESD has made and
documented progress to meet the requirements in 40 CFR parts 50 and 58.
The MCESD was required by the Agency to develop a Corrective Action
Plan (CAP) to address deficiencies documented in the 1992 Re-
Evaluation. The progress on the CAP is being monitored by EPA, Region
IX Air Quality Section and Compliance and Oversight Section, through
review and verification of progress reports by MCESD and visits with
the MCESD Air Monitoring Program personnel. EPA has also withheld
federal grant money to encourage the MCESD to address CAP commitments
and regulatory requirements in a timely manner. There have been
improvements by MCESD, [[Page 18014]] including revising the Quality
Assurance Program Manual (conditionally approved by Region IX pending
minor additions), revamping its entire PM10 network with new
equipment including four continuous PM10 samplers, quality
assurance training for air monitoring staff, and others.
    Comment: A 1992 audit by Dames and Moore (DM) found that the
monitoring network did not have adequate numbers of neighborhood scale
and middle scale monitors, as directed by EPA guidance. Several
homogenous subregions in the area have no monitoring station or one
station. In addition, little or no monitoring is conducted within 500
meters from several major sources. DM also found that the total number
of monitoring stations is far below that required by EPA guidance.
Under EPA spatial siting guidelines, there should be approximately 94
monitoring stations in the nonattainment area. Yet the SIP shows only 9
permanent PM10 stations. DM also found that the monitoring program
was inadequately staffed.
    Response: EPA does not agree with the DM audit's comments on
network adequacy, particularly concerning the necessary number of air
monitoring sites recommended by DM. EPA criteria, in 40 CFR part 58,
requires the Maricopa County network to consist of six (6) to ten (10)
National Air Monitoring Stations (NAMS). The district is also required
to operate State and Local Air Monitoring Stations (SLAMS). Part 58
does not contain a numerical requirement for SLAMS. Maricopa County's
network consists of six (6) NAMS, two (2) SLAMS, and five (5) Special
Purpose Monitoring Stations (SPMS), for a total of thirteen (13) SLAMS
(NAMS are defined as a subset of SLAMS). The network's only deficiency
is that it lacks a category (a) NAMS site with a high concentration
monitoring objective. But this deficiency is being corrected and a
special purpose monitor has been set up at the proposed location for a
Category (a) site. An EPA protocol provides that this sampler will be
run for at least one year. The data will then be evaluated to determine
if the site meets the objectives and should be proposed as a NAMS.
However, even without a category (a) site, the MCESD air monitoring
network is measuring PM10 values above the 24 hour standard.
    Part 58 requirements for ambient air monitoring networks intend the
SLAMS networks to be representative of the four basic monitoring
objectives stipulated in part 58 over the air basin. See 40 CFR part
58, appendix D. Annual network reviews are requested of the districts
and evaluated by the EPA to insure it is representative of the
monitoring stations and to insure optimum use of resources. EPA,
therefore, disagrees that 94 monitoring stations should be required in
the nonattainment area.
    Comment: In a May 15, 1992 letter to the State EPA stated that the
SIP must include provisions for follow-up monitoring and annual network
reviews. The State was to insure that the monitoring network in place
as of January 1, 1994, would be appropriate to evaluate attainment. EPA
also stated that the SIP revision should include a plan for
establishing PM10 episode monitoring stations. None of these
requirements have been met in the form of enforceable, funded
commitments by the State or local governments.
    Response: The State has addressed these requirements in the
PM10 SIP revision for the PPA which is enforceable now on the
State level, and which will be enforceable federally once this final
notice becomes effective. Appendix B, Exhibit 14 contains additional
information on the County's air quality surveillance system. Appendix
B, Exhibit 15 contains the County's Rule 510--Air Quality
Standards--which provides for the establishment of pollutant monitoring
in accordance with EPA guidance and Federal regulations. Appendix B,
Exhibit 16 contains the County's Rule 600 which addresses emergency
episodes. Appendix B, Exhibit 17 contains further information on the
State's procedures for the prevention of emergency episodes.
    Comment: The technical support document accompanying EPA's proposed
rulemaking asserts that the SIP provides for correction of the
monitoring deficiencies by January 1, 1994. We ask EPA to identify
precisely where the SIP shows a legally enforceable commitment to this
effect, and where the SIP shows a commitment of financial resources to
complete the job. Moreover, because the January 1, 1994 date has long
since passed, the correction of deficiencies should now be complete. We
ask EPA to indicate where the State has documented actual correction of
the deficiencies, if this has in fact occurred.
    Response: As discussed in the preceding response, Maricopa County
has made documented progress in meeting all of the Federal air quality
monitoring requirements. The appendices to the PM10 plan, cited
above, provide specific information on the County's progress in
correcting deficiencies with the monitoring network.
2. Emission Inventory
    Comment: The State's emission inventory is not accurate or current
as required by the CAA.
    Response: EPA disagrees with this comment and believes that the
emissions inventory is accurate to within an acceptable degree of
uncertainty. The State followed EPA-recommended emissions inventory
procedures in use at the time of inventory preparation. A degree of
uncertainty is particularly associated with PM10 inventories
because PM10 emissions are especially time- and place-specific.
Emission factors from a study in one area may differ for another area.
PM10 emissions also vary with activity levels and there are many
activities, such as residential wood burning, for which there has been
little accurate quantification. EPA recognizes that there are some
differences between the emissions inventory fractions estimated from
usual inventory methods and the source proportions determined from
Chemical Mass Balance (CMB) modeling. However, EPA does not consider
these differences to invalidate the inventory. The monitored results
used in the CMB analysis reflect differences in distance, dispersion,
and deposition of the emissions from various PM10 sources. A
source's contribution at a particular monitor is not expected to be in
the same proportion as its contribution to the area's total emissions.
This explains the inventory/CMB discrepancies.
    Furthermore, accuracy of the emissions inventory is not critical to
demonstrating impracticability of attainment. This is because a
demonstration of impracticability may be based on the CMB apportionment
results and not specifically on the emissions inventory. The inventory
total is used only as a normalization scaling factor. EPA may have
reached a different conclusion if, for example, the State sought to
rely on a dispersion model, which requires a more accurate emissions
inventory, instead of the CMB receptor model. However, based on the
selected modeling, EPA believes that the inventory is sufficiently
accurate to comply with the requirements of the Act and, more
specifically, to serve as the basis for the demonstration of
impracticability.
3. Modeling
    Comment: The SIP does not meet the requirements of the Act and EPA
guidance for an adequate modeling analysis.
    Response: EPA disagrees with this comment. The State's modeling
[[Page 18015]] complies with EPA guidelines, which allow for a receptor
model such as CMB even though a dispersion model is recommended when
possible. See Memorandum from John Calcagni, ``PM10 SIP
Demonstrations Policy for Initial Moderate Areas'' (March 4, 1991).
    EPA recognizes that the State attempted to validate a dispersion
model but was unsuccessful, in large part because of the degree of
spatial and temporal accuracy required in the emissions inventory for
use as input to a dispersion model. EPA believes that the State
provided a reasonable level of effort to develop its dispersion model.
Because it failed, however, the State is justified (and provided its
justification in the SIP revision) in using a CMB receptor model. EPA
has determined that the State's modeling complies with EPA guidelines.
    EPA also anticipates the PPA will be reclassified as a serious
area. Reclassification will provide additional time for the State to
improve its modeling. When the State ultimately seeks to make an
attainment demonstration, EPA will apply more stringent criteria for
the spatial and temporal accuracy of the emissions inventory,
corroborating models, and treatment of secondary particulates.
Nevertheless, EPA believes that the modeling submitted by the State in
this PM10 SIP revision complies with the requirements and guidance
established by EPA for a moderate area SIP revision and demonstration
of impracticability.
    Comment: EPA's proposed finding that PM10 precursors do not
contribute significantly to PM10 levels that exceed the NAAQS in
the PPA was made without any objective standard against which to
measure significance. EPA's proposed action on this issue is arbitrary
and capricious.
    Response: EPA disagrees with this comment. EPA recognizes that on
individual sampling days there were detectable contributions of one
PM10 precursor, secondary ammonium nitrate. Yet the average
overall contribution of secondary ammonium nitrate was less than five
percent of the total annual inventory. See 1989-1990 Phoenix PM10
Study, Volume II: Source Apportionment, DRI, April 12, 1991, p. S-2.
This magnitude of contribution is not significant for purposes of this
action, although EPA acknowledges that such a contribution might
warrant further attention if the State were attempting to submit an
attainment demonstration for the 24-hour NAAQS. EPA believes that a
contribution of less than five percent secondary ammonium nitrate is
within the degree of uncertainty and is near the ``noise'' level for
CMB results.
    In general, because of the complexity of the chemistry involved,
there is no EPA-recommended method and no scientific consensus for
dealing with secondary particulates. A number of PM10 areas have
dealt with this problem by assuming that secondary particulates are
roughly proportional (or scale) to emissions of primary particulates.
EPA believes that in the absence of better scientific or technical
information, including better EPA guidance, this approach is
reasonable. Consistent with this approach, the PPA scaled down their
total PM10 emissions inventory to exclude the contributions from
PM10 precursors. Indeed, if the PPA had included the contributions
from PM10 precursors, this would have resulted in the recording of
proportionately higher concentrations of PM10 in excess of the
NAAQS. Therefore, if the PPA had explicitly accounted for the
contribution of PM10 precursors, the State's conclusion that
attainment is impracticable would be strengthened, not weakened.
4. Mobile Source Budget
    Comment: ACLPI states that in order to determine conformity of
transportation plans, projects, and programs with this SIP, a mobile
source emission budget must be identified.
    Response: EPA does not agree that the State was required to
identify a mobile source emission budget. The moderate area SIP
revision for the PPA demonstrates that attainment of the PM10
NAAQS is impracticable by December 31, 1994. Mobile source emission
budgets are only required to be identified in SIP revisions which
demonstrate attainment. The preamble to EPA's transportation conformity
rule states:

    Some moderate PM10 nonattainment areas may have submitted
SIPs which demonstrate that the area cannot attain the PM10
standard by the applicable attainment date. These areas have been or
will be reclassified as serious areas under section 188(b) of the
Clean Air Act. Such SIPs which do not demonstrate attainment do not
have budgets and are not considered control strategy SIPs for the
purposes of transportation conformity.

58 FR 62196, November 24, 1993.
    Thus, EPA's transportation conformity rule explicitly contemplated
and determined that PM10 areas demonstrating impracticability,
like the PPA, would not have provided for and would not be required to
identify a mobile source emission budget until an approvable attainment
demonstration is submitted.

B. Demonstration of Impracticability

    Comment: The State's demonstration of the impracticability of 1994
attainment is contrary to both the language and purpose of the Act. The
plain thrust of sections 188 and 189, in combination with section 172,
is that states should make every effort to attain by 1994. Rather than
searching for combinations of control measures that would produce
timely attainment, the state merely lists 13 control measures, asserts
that they are insufficient to attain by 1994, and then ``finds'' that
impracticability has been demonstrated.
    Response: EPA disagrees. As discussed throughout this document,
including in relevant responses to comments, EPA has determined that
Arizona has implemented all RACM, and that the correct number of
implemented measures is 67. EPA has also determined that the PPA has
complied with the requirement of section 172(c)(2) that it demonstrate
it is meeting RFP, by showing a measurable increment of PM10
reductions between the baseline and the emissions reductions achieved
through implementation of all RACM. EPA believes, therefore, that
Arizona's SIP submittal does not contain mere assertions, but
appropriate and acceptable demonstrations that are consistent, not only
with the criteria contained in EPA's guidance, but with the Act's
language and purpose as well. Again, as discussed further elsewhere in
this Notice, EPA also believes that Congress recognized that many areas
initially designated Moderate for PM10 would not be capable of
developing SIP revisions which demonstrated attainment by the
applicable attainment date. This is evident by the fact that, for
PM10, the Act also allows States to demonstrate earlier than the
applicable attainment deadline that implementation of RACM will not
provide for attainment and, thus, that attainment by the Moderate area
deadline is impracticable. Since this provision is unique to PM10
(the Act generally provides fixed attainment dates for other pollutants
which, if the area fails to meet, subjects it to a mandatory ``bump-
up''), it seems clear that the language and intent of the Act are to
first provide PM10 areas with an opportunity to attain the NAAQS
through the implementation of reasonable, but not necessarily
exhaustive, efforts (i.e. RACM), and then to provide those areas that
cannot achieve the NAAQS by the applicable attainment date with an
alternative--to demonstrate that attainment is impracticable. However,
such areas [[Page 18016]] must then go through a second planning effort
which will require the implementation of more stringent measures, i.e.
BACM.
    Comment: ACLPI commented that the State's demonstration of
impracticability is deficient because it fails to address the 24 hour
standard.
    Response: EPA disagrees that the impracticability of meeting both
standards must be demonstrated. The PPA cannot be redesignated to
attainment for PM10 until the State can demonstrate that the SIP
provides for attainment of both the annual and the 24-hour NAAQS.
Conversely, if the SIP demonstrates that even with the implementation
of RACM it cannot attain any one of the standards (annual or 24-hour)
by December 31, 1994, then it has demonstrated that PM10
attainment is impracticable. As an additional matter, it should be
noted that the PPA is proportionately farther above the 24-hour NAAQS
than it is above the annual NAAQS. Thus, given that the
impracticability of attaining the annual NAAQS has been demonstrated,
EPA agrees with the State's conclusion that attaining the more
difficult 24-hour NAAQS would likely be shown to be similarly
impracticable.
    Comment: ACLPI commented that EPA should not evaluate
practicability from the present point in time: i.e., whether attainment
by December 31, 1994 is now practicable. The issue is whether timely
attainment would have been practicable had the state implemented all
RACM as expeditiously as practicable, and no later than December 10,
1993. ACLPI also states that, based on the decision in Delaney v. EPA,
898 F. 2d 687 (1990), the state would be obligated to provide for
attainment as soon as possible if achievable via implementation of RACM
as expeditiously as practicable.
    Response: EPA is concluding in this action that Arizona has met the
Act's requirement to implement all RACM by December 10, 1993. EPA is
also concluding that the State has demonstrated that attainment of the
PM10 NAAQS by December 31, 1994, is impracticable even with timely
implementation of all RACM. EPA therefore believes that the detailed
explanations in this notice, including those contained in other
relevant responses to comments, and in the accompanying technical
support document should adequately address the issue raised by this
comment. EPA further believes that the requirements that are relevant
to consider are those contained in the CAA, as amended in 1990, and not
statements taken from the Delaney opinion, which was construing
requirements under the CAA as amended in 1977. As stated previously in
this document, sections 172(c) and 189(a)(1)(C) when read together
require the implementation of all RACM as expeditiously as practicable
but no later than December 10, 1993. Additionally, section 189(a)(1)(B)
requires either a demonstration that the plan provides for attainment
by December 31, 1994 or a demonstration that attainment by that date is
impracticable. Since EPA believes both that the RACM implementation
requirement has been met and that an acceptable demonstration of
impracticability has been provided by the State, no further response is
required.

C. RACM

    Comment: ACLPI commented generally that the SIP, EPA Guidance and
public comments identified 161 potential measures as RACM, but that the
revised PM10 SIP rejected all but 13 of the measures without
providing adequate justification. Similarly, the state adopted only one
new transportation control measure, while failing to adopt, without
explanation, every other potentially available TCM.
    Response: The general and detailed comments by ACLPI concerning
RACM raise difficult issues concerning the State planning requirements,
and EPA appreciates the time and thought that ACLPI has contributed to
this process. However, ACLPI has misunderstood the number of measures
that the State implemented or rejected as RACM. The revised PM10
SIP did not reject all but 13 measures from the list of possible RACM.
As discussed below and in substantial detail in the accompanying TSD,
the State has implemented all possible RACM (in some cases, by
demonstrating that partial implementation of a measure is all that was
reasonable to implement by December 10, 1993) and has provided EPA with
a reasoned justification for the rejection of the remaining measures as
not constituting RACM.
    EPA disagrees with ACLPI regarding its RACM interpretation as it
relates to transportation control measures (TCMs). In its comments
regarding whether the State should have considered various proposed
TCMs to be reasonably available, ACLPI asserts that the Court of
Appeals for the Ninth Circuit held in Delaney v. EPA, ``that TCMs
listed in section 108 of the Act are presumed to be reasonably
available.'' ACLPI goes on to argue that ``Congress adopted and
endorsed this decision in the 1990 Clean Air Act amendments,'' and
cites for this proposition 136 Cong. Rec. S16971 (daily ed. Oct. 27,
1990). In reliance on these claims, ACLPI concludes that Arizona ``has
failed to rebut the [presumption regarding the] availability of the
section 108 measures in the instant SIP, and therefore the SIP must be
rejected.'' EPA disagrees with both assertions and with the conclusion
ACLPI derives from them as well. In the General Preamble (57 FR 13560-
13561) EPA presents a detailed discussion of its interpretation of the
RACM requirement, including implementation of TCMs. EPA continues to
stand by that interpretation and the General Preamble discussion is
explicitly referenced herein as forming part of the justification for
the action being taken in this document.
    The portion of that discussion that relates to TCMs acknowledges
that in pre-amended Act guidance EPA created a presumption that all of
the TCMs listed in section 108(f) were RACM for all areas, and required
areas to specifically justify a determination that any measure was not
RACM based on local circumstances. However, EPA then explicitly
repudiated that earlier guidance, explaining that, based on its
experience in implementing TCMs in subsequent years, local
circumstances varied to such a degree that it was inappropriate to
presume that all of the measures listed in section 108(f) were per se
reasonably available for all nonattainment areas. See 44 FR 20372-20375
(April 4, 1979). Under EPA's revised guidance, all states are required,
at a minimum, to address the section 108(f) measures, and where such a
measure is determined to be reasonably available to implement it in
accordance with section 172(c)(1).
    With respect to Delaney, the General Preamble states EPA's belief
that the court did not hold, as ACLPI claims, that the statute required
the Agency to interpret the RACM requirement to create a presumption
that all TCMs are reasonably available. Instead, the court held that
EPA itself had created such a presumption and, therefore, was bound to
apply its own then-applicable 1979 RACM guidance. An administrative
agency is permitted to revise or alter prior guidance so long as that
guidance continues to represent a reasonable interpretation of the
statutory requirement. Nothing in the court's decision precluded EPA
from revising its own guidance based on later experience in
implementing TCMs. EPA also believes that the Senate managers'
statement endorsing the Agency's 1979 RACM guidance as construed by the
Delaney court reflected the view of several legislators who had wanted
the Senate Committee bill to require that all section 108(f) measures
be implemented [[Page 18017]] in severe nonattainment areas. However,
the final version of the Senate bill did not adopt this position.
Consequently, any subsequent statements by any legislators that appear
to consider the interpretation relating to TCMs in EPA's 1979 RACM
guidance as still being applicable post-1990 could not be said to
reflect the views of the Congress as a whole, and thus should not be
accorded weight.
    Sections 172(c) and 189(a)(1)(C), along with relevant EPA guidance,
require the State to implement all RACM provisions in its moderate area
plan to reduce PM10 emissions. EPA's proposed approval of the
revised PM10 SIP concluded that there was an initial list of 161
potential RACM. See 59 FR 38404. EPA has determined that the State
implemented 67 of those measures as RACM. Of the remaining 94 potential
RACM, 62 measures were duplicates of other measures. Finally, EPA
believes that the State acted in accordance with Agency guidance in
determining that the remaining 32 measures were not in fact, reasonably
available because either; (1) The source made a de minimis contribution
of PM10 or (2) the measure was rejected on the basis of economic
or technological infeasibility. Thus, EPA has determined that the State
has satisfied its moderate area RACM requirements under sections 172(c)
and 189(a)(1)(C).
    In some cases, RACM has been met through partial implementation of
a measure, such as doubling rather than tripling bus service or
implementing measures only in populous municipalities. The State
provided more detailed justification explaining why partial
implementation of many measures constitutes RACM in ``Summary of Local
Government Commitments to Implement Measures and Reasoned Justification
for Non-Implementation for the MAG 1991 Particulate Plan for PM10
and Select Measures from the Clean Air Act Section 108(f)'' (``MAG
Supplementary Document''). The Mag Supplementary Document was submitted
at EPA's request after EPA proposed to approve the revised PM10
SIP in an effort to respond to comments received by EPA claiming that
the SIP submittal did not contain sufficient detail regarding the
State's justification for rejecting potential RACM. The MAG
Supplementary Document has been included in the Administrative Record
for this rulemaking and, to the extent that it provides additional
detail and elaborates on the State's reasoning regarding its RACM
determination, forms, in part, a complementary basis for EPA's final
approval of the State's revised PM10 SIP, including EPA's finding
that the State complied with its obligation under Sections 172(c) and
189(a)(1)(C) to implement all RACM.
    The list of 67 RACM the State has implemented includes 41 measures
that were adopted in the State's 1993 Carbon Monoxide and Ozone Plans
(``1993 CO Plan''). EPA believes that adoption and inclusion of the
measures in the 1993 CO Plan is a sufficiently meaningful and legally
binding action by the State which, moreover, constitutes compliance
with the Act's requirement to submit a plan which includes provisions
to assure that RACM is implemented no later than December 10, 1993.
ACLPI's comments on individual measures addressed in the accompanying
TSD state that certain measures have not been adopted ``in committed
form.'' For the measures in the 1993 CO Plan, EPA believes that the
State has provided adequate evidence that the plan is being implemented
and is enforceable. The State's 1993 CO plan builds upon the control
strategy developed and adopted for the MAG 1987 CO plan. Many of the
measures in the 1993 CO plan continue implementation of transportation
control measures included in the 1987 CO plan. The 1993 CO plan also
contains new control measures that were not in the 1987 CO plan. EPA is
aware that, for the most part, the State is not claiming PM10
emission reduction credits for the measures developed for their CO and
ozone plans. The PM10 SIP does take emission reduction credit for
Maricopa County's Trip Reduction Ordinance and the operation of two
alternative fueled buses. The State explained instead that reductions
from RACM in the 1987 CO Plan were calculated in the 1989 baseline
PM10 emission inventory. These CO measures may qualify as RACM
regardless of whether emissions reduction credit can be assigned, as
noted by EPA's proposed approval, stating: ``These CO measures are
included in the PM10 SIP revision because they could also reduce
particulate matter emissions.'' 59 FR 38404. EPA has not received
direct adverse comment on the proposal to include the CO measures in
the State's revised PM10 SIP as RACM, and is therefore taking
final action on that proposal. The 41 measures from the CO and Ozone
Plans that are treated as RACM in the revised PM10 SIP are listed
in the TSD, Attachment #2, for this NFRM.
    In addition to RACM from the 1993 CO Plan, the State is
implementing measures required by national rulemakings. These measures
are also RACM for the moderate area PM10 SIP. For example, the
State must ensure that cleaner commercial aircraft land in the PPA
based on the federal Airport Noise Control Act, 49 U.S.C. App. 2151
(1990) (ANCA). Municipalities in the PPA are required to comply with
ANCA. Thus, even though the clean aircraft requirement is established
by ANCA, it also satisfies the State's obligation to assure
implementation of RACM. EPA believes the State may satisfy the RACM
obligation pursuant to compliance with ANCA rather than through
adoption in the revised PM10 SIP of measure No. 45, ``Replacement
of High Emitting Aircraft,'' offered in the public comments. The
accompanying TSD lists RACM which are based on national rulemakings or
emissions standards.
    For diesel fuel controls, EPA believes that the State has
adequately demonstrated that partial implementation of this measure
through compliance with national diesel fuel standards is RACM, and
that the State has also justified rejecting implementing the California
diesel fuel standards as RACM. Likewise, the State's partial
implementation of a measure requiring conversion of its diesel fleet to
clean fuels constitutes RACM. The State has also partially implemented
measures regulating nonroad utility heavy duty engines and utility
engines through compliance with national standards. EPA believes that
partial implementation of this measure is all that was reasonable for
the state to implement by December 10, 1993. The implementation of
controls associated with diesel fuels and engines is discussed more
fully in the accompanying TSD. The TSD also discusses the State's
justification for rejecting as RACM an inspection and maintenance
testing program for diesel vehicles.
    Comprehensive rules are another source of RACM. The State submitted
several comprehensive rules, such as Rules 310, 311, 314 and 316, that
encompass RACM that are separate from the initial list of 161 possible
measures. For example, Rule 310 addresses 13 of the 15 measures that
EPA considered to be reasonably available for the control of fugitive
dust. See 59 FR 38404. The accompanying TSD provides a more detailed
discussion of RACM for fugitive dust based on implementation of Rule
310. To control residential wood combustion, Maricopa County has
adopted a new rule, Residential Woodburning Restriction Ordinance
(RWRO), and the State has included a provision in HB 2001 that provides
a personal income tax deduction for people that purchase EPA-certified
wood heaters. The County also has a [[Page 18018]] public education and
awareness program in place to inform residents of the impacts of
residential wood combustion on air quality and public health and the
requirements of the County's woodburning restriction ordinance. These
measures cover all of the four RACM listed by EPA in its General
Preamble to address particulate matter emissions from residential wood
combustion. The State's adoption of the County's RWRO satisfies the
obligation to adopt measures to reduce emissions from residential wood
combustion. As with measures in the 1993 CO Plan, EPA believes that the
State has adopted the RWRO in sufficiently meaningful legal form to
ensure that RACM is being implemented in compliance with the Act. The
TSD also discusses this measure.
    From the initial list of 161 possible RACM, EPA determined that 62
measures are duplicates of others and consequently did not require any
further consideration. These duplicate measures are also listed in the
TSD, Attachment #1.
    Finally, EPA has determined that the State was justified in
rejecting 32 of the remaining measures from the list of 161 possible
RACM. These measures, which are listed in the TSD, Attachment #3, were
discussed in EPA's proposed approval, 59 FR 38404, and are not
reasonably available because they are either de minimis or economically
or technologically infeasible. Certain measures are not reasonably
available because the contribution from the source is de minimis in the
PPA, such as Public Comment No. 37 which provides for reducing
emissions from ship berthing. There are no ship berthing facilities in
the PPA. Alternatively, the State has provided reasoned justifications
to reject certain measures as RACM based on economic or technological
infeasiblity, such as railroad electrification. Those measures rejected
from the initial list of 161 possible RACM, and the justifications for
such rejections, are provided in the accompanying TSD.
    For the reasons stated above, EPA has determined that the State has
satisfied its obligation under the Act to submit a plan containing
provisions to assure that RACM has been implemented by December 10,
1993, and, consistent with Agency guidance, has provided a reasoned
justification for rejecting other potential measures on grounds that
they are not RACM. The accompanying TSD provides a detailed response to
each specific measure or type of measure that was raised in ACLPI's
comments on the RACM portion of EPA's proposed approval of the State's
revised PM10 SIP. Many other measures were duplicates of measures
that were either adopted or rejected. For the remaining measures which
the State rejected, EPA has given careful consideration to ACLPI's
thorough comments. On balance, however, the State has complied with its
obligation to provide EPA with a reasoned justification for the
rejection of the remaining potential RACM.

D. RFP

    Comment: The SIP fails to show RFP as required by section 172(c)(2)
of the Act. According to the SIP, emissions of PM10 increase in
1994 compared to the baseyear.
    Response: EPA disagrees with the commenter's assertion that the SIP
does not demonstrate reasonable further progress in reducing PM10
emissions. While the State's demonstration showed a small reduction in
PM10 emissions from the implementation of Maricopa County's Rule
310--Fugitive Dust, EPA believes that the emission reduction that the
State associated with this rule was overly conservative. When the State
calculated the emission reduction potential for Rule 310, they only
applied the control effectiveness to the urban portions of the PPA. EPA
believes the control effectiveness should have been applied to the
entire nonattainment area since the rule applies throughout Maricopa
County which includes the entire nonattainment area. When EPA
recalculated the emission reduction benefits of the SIP's control
strategy the reduction potential equals 8,677 tons per year. The 1989
base year inventory is 40,975 tons per year and was projected to grow
to 45,981 tons per year in 1994. Therefore, the total 1994 projected
inventory after application of RACM would equal 37,304 tons per year
which shows, consistent with EPA's guidance on demonstrating RFP, which
is described in greater detail earlier in this notice, that the area
has indeed made progress in reducing emissions from the base year
total, and thus has demonstrated it has met the requirements of section
172(c)(2) for the period 1990-1994.

E. Rules

    Comment: Rule 310 is not approvable because the rule does not meet
the Act's or EPA's criteria for enforceability. The rule must make
clear to whom it applies and be sufficiently specific that a source is
fairly on notice as to the standard it must meet. No threshold level of
dust generation is specified, leaving sources to guess as to when the
ordinance will be triggered.
    Response: Rule 310 does specify the sources that are subject to
control. Rule 310 applies to any activity, equipment, operation and/or
man-made or man-caused condition or practice capable of generating
fugitive dust. Section 300 of the Rule further specifies the types of
activities and sources of fugitive dust that are subject to the rule's
requirements (e.g., vehicle use in open areas and vacant parcels;
unpaved parking areas/staging areas; unpaved haul/access roads;
disturbed surface areas; vacant areas; material handling operations;
material transport; haul trucks; roadways, streets and alleys; and
cattle feedlots and livestock areas). Further, as discussed in more
detail in response to the next comment, the requirements of Rule 310
are triggered if a source of fugitive dust violates either the 20%
opacity standard in Section 301 or the requirement to implement RACM in
Sections 301 through 314. Thus, any activity that causes visible
emissions in excess of 20 percent opacity or any activity that is
carried out contrary to the implementation of RACM is a violation of
Rule 310. For new sources of fugitive dust, Rule 310 requires
compliance with an approved dust control plan as implementation of
RACM, subject to approval by the control officer; existing sources of
fugitive dust are required to comply with the RACM defined in the Rule.
    Comment: The standards of performance [in Rule 310] are equally
vague. The rule merely states that reasonably available control
measures must be applied. That term is in turn defined merely by
listing examples of vaguely described control steps without requiring
use of any specific measure or a specific level of effort in any
specific context. Thus, any specific level of control that the County
seeks to impose will be subject to challenge.
    Response: ACLPI's comments tend to oversimplify the requirements of
Rule 310. Because of the very many different circumstances under which
fugitive dust can be generated, it would be nearly impossible for the
County to predict every situation and prescribe a specific control
measure for it. As noted above, Rule 310 contains two standards to
enforce. One standard with which all sources are required to comply is
the 20% opacity limit. The second standard is the RACM requirement. New
sources of fugitive dust are required to comply with approved dust
control plans, which become enforceable as permit conditions. For
existing sources of fugitive dust, Rule 310 addresses the variability
of sources and activities by either prescribing RACM (see, e.g.,
Section 311.2) or listing potential reasonably available fugitive dust
control measures (see, e.g., Sections 306 [[Page 18019]] & 221). Yet
Rule 310 allows a source to tailor its own control strategy to fit its
particular situation and EPA believes that such flexibility is
necessary. When the activity or situation does not involve a high
degree of variability, the measures that apply to that source are
typically more prescriptive. For example, Section 311.2, which applies
to all haul trucks operating in the PPA, sets forth specific
requirements as RACM. If haul trucks fail to implement these measures,
there is a violation of Rule 310. Even if the haul trucks comply with
Section 311.2, but still violate the 20% opacity standard, there is a
violation of Rule 310. Other sections of the rule are equally
enforceable through permit conditions. Section 303 of Rule 310 requires
that a permit application for any new source subject to Section 302 of
Rule 310 shall include a Control Plan to prevent or minimize fugitive
dust, and the Control Plan must be approved by the County Control
Officer. If the County determines through a violation of the separate
20% opacity standard that a Control Plan is not sufficient to control
fugitive dust, the responsible party is required to revise the control
plan accordingly. Thus, the County will be able to enforce the
provisions of this Rule 310 through two standards: the 20% opacity
standard and the requirement to implement RACM through a Control Plan
or as defined in the Rule.
    The original version of Rule 310 that was submitted to EPA
contained a provision that EPA believed threatened the enforceability
of the rule. The original rule contained a provision (221.9) that
allowed the Control Officer to approve the use of alternative control
methods not listed in the rule. This provision has since been deleted
from Rule 310.
    Comment: The State and County have not committed the necessary
resources and personnel to ensure enforcement of rules 310, 311, 314,
and 316, as required under section 110(a)(2)(E) and EPA guidance. Nor
does the SIP contain a program to provide for enforcement of any of the
SIP control strategies, as required by section 110(a)(2)(C) of the Act.
    Response: The County has committed the necessary resources and
personnel to implement rules 310, 311, 314, and 316. Details on the
level of personnel and funding, as required by section 110(a)(2)(E) of
the Act, as well as enforcement strategies as required by section
110(a)(2)(C) of the Act are provided in the document ``MAG 1991
Particulate Plan for PM10 for the Maricopa County Area and 1993
Revisions, Commitments for Implementation, Volume Three'', section
entitled ``Maricopa County''.

F. Other

1. Public Comment
    Comment: In the process of developing and submitting the PM10
SIP revision for Phoenix, MAG and the State have on several occasions
failed in their responsibility to seriously consider public comment
prior to adopting plans.
    Response: The State has provided a section in all of its PM10
SIP submittals which includes all public comments received and the
State's responses to those comments.
2. State Assurances
    Comment: The PM10 SIP does not contain, as required by section
110(a)(2)(E)(iii) of the CAA, the necessary assurances that, where the
State has relied on a local or regional government, agency, or
instrumentality for the implementation of any plan provision, the State
has responsibility for ensuring adequate implementation of such plan
provision.'' While the State contends that this requirement is met by
A.R.S. Sec. 49-406.J, the process laid out by this State statute does
not meet the plain requirements of section 110(a)(2)(E)(iii) and is
completely inconsistent with the Act's requirements for SIP
enforceability, timely implementation of control measures, and
expeditious attainment.
    Response: EPA has historically adopted a rule of reasonableness in
construing the language of section 110(a)(2)(E)(iii) of the Act with
respect to the extent to which the State must show that its plan
evinces a showing of responsibility sufficient to ensure adequate
implementation of the plan's provisions by local or regional
governments. EPA, for example, does not require the State to adopt into
its own plan the local government's implementing provisions, but has
considered it sufficient for the State to describe and reference those
provisions and the accompanying descriptions of the local
municipalities intended implementation actions. The State has included
in its plan submission a copy of the Arizona Laws Relating to
Environmental Quality, Sec. 49-406. J. of which contains the assurances
required by section 110(a)(2)(E). If any person fails to implement an
emission limitation or control measure, the relevant State official is
required to issue a written finding to that effect, which may also
necessitate the holding of a conference regarding the failure with the
offending person. If a determination is made that the failure has not
been corrected, the attorney general, at the responsible official's
request, must file an action, seeking either ``a preliminary
injunction, a permanent injunction, or any other relief provided by
law.'' Section 49-407 of the Arizona Revised Statutes provides that
citizens may sue the director to perform his or her duty. While some
opportunity is provided to rectify problems short of taking legal
action, EPA does not believe this is unreasonable, nor that the
affected State officials ultimately have discretion to ignore the law's
requirements. The comment engages in some speculation, describing
several possible scenarios under which implementation by the local
authorities may not occur. Despite these concerns--which are admittedly
speculative--EPA believes, based on its experience in administering
this provision of the Act, that the relevant sections of the State's
law provides an adequate degree of assurance that the control measures
in the plan are enforceable and will be fully implemented.

VI. Executive Order 12866

    The Office of Management and Budget has exempted this regulatory
action from Executive Order 12866 review.

VII. Regulatory Flexibility

    Under the Regulatory Flexibility Act, 5 U.S.C. 600 et seq., EPA
must prepare a regulatory flexibility analysis assessing the impact of
any proposed or final rule on small entities. 5 U.S.C 603 and 604.
Alternatively, EPA may certify that the rule will not have a
significant economic impact on a substantial number of small entities.
Small entities include small businesses, small not-for- profit
enterprises, and government entities with jurisdiction over populations
of less than 50,000.
    SIP approvals under section 110 and subchapter I, part D of the
Clean Air Act do not create any new requirements, but simply approve
requirements that the State is already imposing. Therefore, because the
federal SIP approval does not impose any new requirements, I certify
that it does not have a significant impact on small entities affected.
Moreover, due to the nature of the federal-state relationship under the
Clean Air Act, preparation of a regulatory flexibility analysis would
constitute federal inquiry into the economic reasonableness of state
action. The Clean Air Act forbids EPA to base its actions concerning
SIPs on such grounds. Union Electric Co. v. U.S. E.P.A., 427 U.S. 246,
256-66 (S.Ct. 1976); 42 U.S.C. 7410(a)(2). [[Page 18020]]

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Particulate matter, Reporting
and recordkeeping requirements.

    Note: Incorporation by reference of the State Implementation
Plan for the State of Arizona was approved by the Director of the
Federal Register on July 1, 1982.

    Dated: February 28, 1995.
Felicia Marcus,
Regional Administrator.

    Part 52, chapter I, title 40 of the Code of Federal Regulations is
amended as follows:

PART 52--[AMENDED]

    1. The authority citation for part 52 continues to read as follows:

    Authority: 42 U.S.C. 7401-7671q.

Subpart D--Arizona

    2. Section 52.120 is amended by adding paragraphs (c) (67)(i)(B),
(73), (74), and (77) and by adding and reserving paragraphs (c) (72),
(75), and (76) to read as follows:

Sec. 52.120  Identification of plan.

* * * * *
    (c) * * *
    (67) * * *
    (i) * * *
    (B) Amended Maricopa County Division of Air Pollution Control Rule
314, adopted July 13, 1988.
* * * * *
    (72) [Reserved]
    (73) Plan revisions were submitted on August 11, 1993 by the
Governor's designee.
    (i) Incorporation by reference.
    (A) The Maricopa Association of Governments 1991 Particulate Plan
for PM10 for the Maricopa County Area and 1993 Revisions, Chapters
1, 2, 3, 4, 5, 6, 7, 8, 10 and Appendices A through D, adopted August
11, 1993.
    (74) Plan revisions were submitted by the Governor's designee on
March 3, 1994.
    (i) Incorporation by reference.
    (A) Maricopa County Division of Air Pollution Control new Rule 316,
adopted July 6, 1993, and revised Rule 311, adopted August 2, 1993.
    (B) The Maricopa Association of Governments 1991 Particulate Plan
for PM10 for the Maricopa County Area and 1993 Revisions, Revised
Chapter 9 adopted on March 3, 1994.
    (75) [Reserved]
    (76) [Reserved]
    (77) Amended regulations for the Maricopa County Division of Air
Pollution Control submitted by the Governor's designee on December 19,
1994.
    (i) Incorporation by reference.
    (A) Maricopa County Division of Air Pollution Control Rule 310,
adopted on September 20, 1994.

[FR Doc. 95-8215 Filed 4-7-95; 8:45 am]
BILLING CODE 6560-50-P
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Approval and Promulgation of Implementation Plans; Arizona- Phoenix Nonattainment Area; PM<INF>10

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