Approval and Promulgation of Implementation Plans; Texas; Houston/Galveston Nonattainment Area; Ozone

Related Material

Other Related Documents

Note: EPA no longer updates this information, but it may be useful as a reference or resource.

[Federal Register: November 14, 2001 (Volume 66, Number 220)]
[Rules and Regulations]
[Page 57159-57196]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14no01-9]

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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[TX-126-1-7477; FRL-7092-2]

Approval and Promulgation of Implementation Plans; Texas;
Houston/Galveston Nonattainment Area; Ozone

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

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SUMMARY: The EPA is fully approving the Texas one-hour ozone attainment
demonstration State Implementation Plan (SIP) for the Houston/Galveston
(HG) severe nonattainment area with an attainment date of November 15,
2007. Also, being published in today's Federal Register are seven
additional actions, approving various measures that support the
attainment demonstration.
In this action, the EPA is approving the following related SIP
elements: The following local measures relied on in the attainment
demonstration: speed limit reduction, voluntary mobile emission
programs (VMEP) and transportation control measures (TCM); the Post
1999 Rate of Progress (ROP) plans for the time periods November 15,
1999 to November 15, 2002, November 15, 2002 to November 15, 2005 and
November 15, 2005 to November 15, 2007; the Motor Vehicle Emissions
Budget (MVEB) contained in the attainment demonstration SIP and the
Post 1999 ROP plans; the 15% ROP Plan (Conversion of conditional
interim approval to a full approval); certain enforceable commitments
to adopt additional measures and perform additional analyses; revisions
to the 1990 base year inventory; and the HG area's SIP as meeting the
reasonably available control measures (RACM) requirement.

DATES: This final rule is effective on December 14, 2001.

ADDRESSES: Copies of documents relevant to this action are available
for public inspection during normal business hours at the Environmental
Protection Agency, Region 6, Air Planning Section (6PD-L), 1445 Ross
Avenue, Dallas, Texas 75202-2733; and, the Texas Natural Resource
Conservation Commission, Office of Air Quality, 12124 Park 35 Circle,
Austin, Texas 78753.

FOR FURTHER INFORMATION CONTACT: Guy R. Donaldson, Air Planning Section
(6PD-L), 1445 Ross Avenue, Dallas, Texas 75202-2733. Telephone Number
(214) 665-7242, E-mail Address: Donaldson.Guy@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document ``we,'' ``us,'' and
``our'' means EPA.

Table of Contents

I. Final Action
A. What Elements of the Texas SIP Are We Approving?
B. What are the Motor Vehicle Emissions Budgets being Approved
in this Action?
C. What Are the Key SIP Submissions Being Approved in this
Action?
D. What Previous Action has EPA Taken?
E. What Changes Have Been Made in Response to Comment on the EPA
and TNRCC Parallel Proposals?
II. What SIP Elements Did We Need to Take Final Action on Before We
Could Approve the Attainment Demonstration?
III. Comments
A. What Comments Were Received?
i. What comments Were Received on the December 1999 Proposed
Approval/Proposed Disapproval?
ii. What Comments Were Received on the July 28, 2000
Supplemental Proposal Concerning MVEBs?
iii. What Comments Were Received on the July 12, 2001 Proposed
Approval?
B. Response to Comments on Attainment Demonstration
1. General Comments
2. Comments on Photochemical Modeling
a. Model Performance
b. Model Inputs
c. Weight of Evidence Analysis
3. Comments on Control Strategies
4. Comments on Enforceable Commitments
5. Comments on Motor Vehicle Emissions Budgets
a. Comments on July 12, 2001 Proposal
b. Comments on July 28, 2000 Supplemental Notice Proposal
6. Comments on RACM
a. Comments on December 16, 1999 Proposal
b. Comments on July 12, 2001 Proposal
C. Response to Comments on Local Measures
1. Comments on Speed Limits
2. Comments on VMEP
3. Comments on TCMs
D. Response to Comments on Post 1999 Rate of Progress Plans
E. Response to Comments on Administrative Record
IV. Administrative Requirements

I. Final Action

A. What Elements of the Texas SIP Are We Approving?

We are fully approving the one-hour ozone attainment demonstration
SIP for the HG nonattainment area as meeting the attainment
demonstration requirements of 182(c)(2) and (d) of the Clean Air Act
(the Act). We proposed this action on July 12, 2001 (66 FR 36655). This
demonstration shows, through photochemical modeling and other evidence,
that through a combination of adopted measures, recent legislation, and
commitments to adopt additional measures the HG area will attain the
one-hour ozone standard by November 15, 2007.
As an integral part of the attainment demonstration, we are
approving and finding adequate the associated MVEBs only until these
emission budgets have been revised pursuant to the State's enforceable
commitments to use MOBILE6 and to adopt additional measures necessary
for attainment and we have found the revised budgets adequate for the
purposes of transportation conformity.
Before approving an attainment demonstration SIP, we must approve
all of the control measures relied on in the demonstration. The
majority of the control measures relied on in the attainment
demonstration have been approved in other Federal Register notices.
(See Section II for a listing of related Federal Register notices.) We
are approving in today's action, certain measures relied upon in the
attainment demonstration and which were submitted December 20, 2000:
the Speed Limit Reductions, the VMEP, and the TCMs. We are also
approving the following related SIP elements:
15% ROP Plan,
The Post 1999 ROP Plans and their associated contingency
measures;
A demonstration that all RACM have been adopted for the HG
nonattainment area; and
Revisions to the 1990 Base Year Inventory.
The revisions to the Post 1999 ROP plans and the RACM analysis that
we are approving today were parallel processed. (See Section I.E. for a
discussion of parallel processing.)
In addition, we believe that for the HG area to be successful in
attaining the one-hour ozone standard, the State must be committed to
certain future actions relating to adopting additional measures and to
future evaluations of the inputs to the plan. To that end, Texas has
included the following enforceable commitments in their State
Implementation Plan which we are approving:
The State's enforceable commitment to perform a mid-course
review (including evaluation of all modeling, inventory data, and other
tools and assumptions used to develop this attainment demonstration)
and to submit a mid-course review SIP revision, with any recommended
mid-course corrective actions, to the EPA by May 1, 2004.
The State's enforceable commitment to perform new mobile
source modeling for the HG area, using

[[Page 57161]]

MOBILE6, our on-road mobile emissions factor computer model, within 24
months of the model's official release; that if a transportation
conformity analysis is to be performed between 12 months and 24 months
after the MOBILE6 official release, transportation conformity will not
be determined until Texas submits an MVEB which is developed using
MOBILE6 and which we find adequate.
An enforceable commitment to adopt rules that achieve at
least the additional 56 tons/day of NO_X emission reductions
that are needed for the area to show attainment of the one-hour ozone
standard and as supported by identified measures that could potentially
be adopted and could achieve the reductions without requiring
additional limits on highway construction.
An enforceable commitment to adopt and submit the EPA by
December 1, 2002 measures to achieve 25% of the 56 tons/day.
An enforceable commitment to adopt and submit to EPA by
May 1, 2004 measures for the remaining needed additional NO_X
reductions.
An enforceable commitment that the rules needed for the
additional NO_X reductions will be adopted as expeditiously
as practicable and the compliance dates will be expeditious.
An enforceable commitment to concurrently revise the MVEBs
and submit them to EPA as a revision to the attainment SIP if
additional control measures reduce the motor vehicle emissions budget
(MVEB).
This action also satisfies the last two elements of section
182(d)(1)(A) of the Act to adopt TCMs as necessary to comply with the
reasonable further progress and attainment demonstration requirements
of the Act. The first requirement to offset growth in emissions from
growth in vehicle miles traveled (VMT) or number of vehicle trips is
addressed in a corresponding action published separately in today's
Federal Register. Please see Section III.C.3 for additional discussion
regarding the second and third elements. For additional discussion
regarding the first element, see the corresponding separate action in
today's Federal Register regarding the VMT Offset Plan.
For more discussion on the rationale for the actions being approved
here, see the proposed approvals with their associated Technical
Support Documents (TSD) and our response to comments found in Section
II.

B. What Are the Motor Vehicle Emissions Budgets Being Approved in This
Action?

Rate of Progress Budgets
The MVEBs established by the Post 1999 Rate of Progress plans and
that we are approving today are contained in Table 1. We find the MVEBs
consistent with all ROP SIP requirements. In addition, we are finding
these budgets adequate for transportation conformity purposes pursuant
to the criteria in 40 CFR 93.118(e)(4) as part of our action on the SIP
rather than using the web posting process because we have moved forward
on this SIP in a quick manner as described in Guidance on Motor Vehicle
Emissions Budgets in One-Hour Ozone Attainment Demonstrations dated
November 3, 1999.

Table 1.--ROP SIP Motor Vehicle Emissions Budgets
[Tons per day]
------------------------------------------------------------------------
Pollutant 2002 2005 2007
------------------------------------------------------------------------
VOC......................................... 100.07 68.52 79.51
NO_X......................................... 260.85 185.48 156.6
------------------------------------------------------------------------

The new 2007 budgets are taken from the attainment demonstration
modeling rather than directly from the ROP calculations. Emissions
estimates used to demonstrate transportation conformity will be derived
using the assumptions used to develop these emissions budgets for the
2007 attainment SIP MVEBs, pursuant to 40 CFR 93.122(a)(6). We find
such MVEBs consistent with ROP.
Attainment Budgets
Table 2 contains the MVEBs established by the attainment plan. We
are approving these budgets today and finding them adequate for
transportation conformity purposes pursuant to the criteria in 40 CFR
93.118(e)(4) as limited below.

Table 2.--2007 Attainment Year Motor Vehicle Emissions Budgets
[Tons per day]
------------------------------------------------------------------------
Pollutant 2007
------------------------------------------------------------------------
VOC.......................................................... 79.51
NO_X.......................................................... 156.60
------------------------------------------------------------------------

We find the MVEBs consistent with all pertinent SIP requirements
and, as described in our proposals, the MVEBs are approved and adequate
for conformity purposes only until these emission budgets have been
revised pursuant to the State's enforceable commitments to use MOBILE6
and to adopt additional measures necessary for attainment and we have
found the revised budgets adequate for the purposes of transportation
conformity.
All States whose attainment demonstration includes the effects of
EPA's Tier II/Low Sulfur program have committed to revise and resubmit
their budgets after EPA releases MOBILE6.(MOBILE6 is the latest version
of the EPA model for estimating mobile emissions. Its official release
is expected in the near future.) The State committed in its April 2000
submission to perform new mobile source modeling for the HG area using
MOBILE6 within 24 months of the model's official release. If
transportation conformity analysis is to be performed between 12 and 24
months of the official release of MOBILE6, transportation conformity
will not be determined until the State submits a new budget which is
developed using MOBILE6 and which we find adequate. The State has
informed the transportation agencies of this commitment. Texas also
commits to concurrently revise the MVEB if adoption of any shortfall
measure affects the MVEB and submit the revision to EPA as a revision
to the attainment SIP.
We are limiting the duration of our approval as described above
because we are only approving the attainment demonstrations and MVEBs
because the States have committed to revise them. Therefore, once we
have confirmed that revised budgets are adequate, they will be more
appropriate than the budgets we are approving today.

C. What Are the Key SIP Submissions Being Approved in This Action?

There have been a number of State submissions in response to the
attainment demonstration requirements of the Act. In this notice, the
key State submissions being considered were provided by the Governor in
letters dated December 20, 2000, and October 4, 2001. The items in the
October 4, 2001 submission have been parallel processed. Parallel
processing means that EPA proposes action on a state rule before it
becomes final under state law. Our July 12, 2001 proposal details the
history of State and EPA actions that preceded these submissions (66 FR
36655).

D. What Previous Actions Has EPA Taken?

There are three proposals related to this action. First, on
December 16, 1999 (64 FR 70548), we issued a proposed approval/proposed
disapproval of the HG ozone attainment demonstration plan (the 1998
plan). This action outlined the actions we believed were

[[Page 57162]]

necessary for the State to develop a fully approvable plan. Second, on
July 28, 2000 (65 FR 46383), we issued a notice of proposed rulemaking
regarding how the adequacy of attainment MVEBs would be handled for the
one-hour ozone nonattainment areas. Finally, on July 12, 2001 (66 FR
36655), we proposed approval of the HG ozone attainment demonstration
plan (the December 2000 plan as proposed to be revised by the State and
finally adopted and submitted in a letter dated October 4, 2001) and
several related actions. In today's notice, we have addressed all of
the comments received on the three proposals.

E. What Changes Have Been Made in Response to Comment on EPA and TNRCC
Parallel Proposals?

In a letter dated June 15, 2001, the Governor of Texas submitted
several items for parallel processing. These items were: certain
commitments; recent legislative changes with their impacts on and
revisions to the proposed control strategy for the HG area; the
corrections and modifications to the Post 1999 ROP plans; a
demonstration that all RACM have been adopted for the HG nonattainment
area; and a modification to the attainment demonstration and MVEB to
revise the emission projection for Heavy Duty Diesel vehicles.
Under parallel processing, EPA takes final action on its proposal
if the final, adopted state submission is substantially unchanged from
the submission on which the proposed rulemaking was based, or if
significant changes in the final submission are anticipated and
adequately described in EPA's proposed rulemaking or result from needed
corrections determined by the State to be necessary through review of
issues described in EPA's proposed rulemaking. Several minor changes
were made by the State in response to comment.
Enforceable Commitments
Texas made the following changes to the language of their
enforceable commitments. Italicized text has been added.
The commission commits to adopt measures necessary to achieve at
least 56 tpd of NO_X emission reductions in the HGA area
above and beyond those reductions already identified by the control
measures listed in Chapter 6, Table 6.1-2.
To demonstrate progress towards the 56 tpd that commitment, the
commission intends to evaluate the following measures and to adopt, by
November 2002, sufficient measures in order to achieve at least 25% of
the estimated 56 tpd needed.
TNRCC also in response to comments now lists all of the enforceable
commitments for the HG area in a single location in Chapter 7.
We agree that these changes are not significant in that they
clarify the intent of the enforceable commitments and therefore, remain
approvable. No further notice is necessary since these changes do not
substantively change the State's proposal.
Changes to the Rate of Progress Plan
TNRCC also revised the tables in the Post 1999 Rate of Progress
Plans in response to EPA comments that the Tables did not reflect the
revised implementation schedules for the point source NO_X
rules. This issue was discussed in our proposed approval which was
based on conservative estimates of the emission reductions. The revised
tables in the October 4, 2001 SIP reflect the new implementation
schedule. No further notice is required since the State made changes as
discussed by EPA in the proposal notice. The following summary table is
based on the revised estimates.

Table 1.--NO_X Rate of Progress
----------------------------------------------------------------------------------------------------------------

----------------------------------------------------------------------------------------------------------------
Milestone Year....................... 2002................... 2005................... 2007.
Target Level......................... 1127.08................ 1011.33................ 935.67.
Projected emissions after controls... 1115.76................ 630.05................. 444.04.
Measures............................. Tier I NLEV RFG I/M Tier I/II I/M HDDV Tier I/II HDDV
Small Engine HDDV Standards. Standards
Standards. NO_X Point Source NO_X Point Source
controls. controls.
----------------------------------------------------------------------------------------------------------------

II. What SIP Elements Did We Need To Take Final Action on Before We
Could Approve the Attainment Demonstration?

In our proposed action on July 13, 2001, we explained that we could
not finalize approval of the attainment demonstration for the HG area
until we finalize approval of several related actions. These actions
are listed below along with the status of their final approval.
1. Vehicle I/M program (30 TAC 114). Final approval published
separately in this issue of the Federal Register.
2. Revised emission specifications in the HG area for
NO_X Point Sources (30 TAC 117). Final approval published
separately in this issue of the Federal Register.
3. NO_X Cap and Trade program (30 TAC 101). Final
approval published separately in this issue of the Federal Register.
4. Low emission diesel fuel (30 TAC 114). Final approval published
separately in this issue of the Federal Register.
5. Non-Road Large Spark-Ignition (LSI) Engines (30 TAC Chapter
114). Final approval published separately in this issue of the Federal
Register.
6. Agreed Orders with Continental and Southwest Airlines and the
City of Houston. Final approval published separately in this issue of
the Federal Register.
7. Reasonably Available Control Technology (RACT) rules regulating
VOCs from Batch Processes (30 TAC 115) and Offset Lithographers (30 TAC
115). Direct final action was published July 16, 2001 (66 FR 36913). No
comments were received and this action became effective September 14,
2001.
8. A determination that the HG SIP includes all Reasonably
Available Control Measures. Final approval in this action.
9. The 15% ROP Plan. Final approval in this action.
10. The Post 1999 ROP Plans and contingency measures. Final
approval in this action.
11. The revisions to the 1990 base year inventory. Final approval
in this action.
12. The speed limit reductions, the VMEP and the TCMs. Final
approval in this action.
13. Lawn service equipment operating restrictions (30 TAC 114.452-
459). Final approval published separately in this issue of the Federal
Register.
14. Vehicle Miles Traveled (VMT) Offset Plan submitted August 25,
1997 and with minor, non-substantive revisions submitted on May 17,
2001. Final approval published separately in this issue of the Federal
Register for the first element of 182(d)(1)(A). The last two elements
of 182(d)(1)(A) are satisfied by this action.
15. Motor Vehicle Idling Limitations (30 TAC 114.500-509). Final
approval

[[Page 57163]]

published separately in this issue of the Federal Register.
16. Stationary Diesel Generator rule (30 TAC 117.206). Final
approval published separately in this issue of the Federal Register.
17. The Post 1996 ROP Plan and contingency measures. Direct final
action was published April 25, 2000, 66 FR 20746. No comments were
received and this rule became effective June 26, 2000.

III. Comments

A. What Comments Were Received?

i. What Comments Were Received on the December 1999 Proposed Approval/
Proposed Disapproval?
The following comment letters were received on the December 1999
proposal:
(1) February 14, 2000 letter from Robert E. Yuhnke, Attorney for
Environmental Defense.
(2) February 14, 2000 letter from Jeffrey Saitas, Executive
Director TNRCC.
(3) July 31, 2000 letter from James O. Bartholomew, ELM Packaging.
ii. What Comments Were Received on the July 28, 2000 Supplemental
Proposal Concerning MVEBs?
The following comment letter was received on this supplemental
proposal.
(1) August 28, 2000 letter from Environmental Defense.
iii. What Comments Were Received on the July 12, 2001 Proposal?
We received the following 13 comment letters on the July 12, 2001
proposal.
(1) Letter from D. Marrach, M.D. dated July 2, 2001.
(2) August 10, 2001 letter from Patrick Gallagher, Sierra Club.
(3) August 13, 2001 letter from John Wilson and Frank Blake, the
Galveston-Houston Association of Smog Prevention (GHASP).
(4)August 13, 2001 letter from B.C. Carmine, Reliant Energy.
(5)August 13, 2001 letter from Ramon Alvarez, PhD, Environmental
Defense.
(6) August 8, 2001 letter from Jack Steele, Houston Galveston Area
Council.
(7) August 13, 2001 letter from Nelly Rocha, Baker and Botts for
the Business Coalition for Clean Air Appeal Group.
(8) August 10, 2001 letter from Albert Axe, Jr., Jenkens & Gilcrest
for TXI Operations.
(9) August 13, 2001 letter from John R. Evans, Lyondell.
(10) August 13, 2001 letter from T. Hefgott, Enterprise Products.
(11) August 3, 2001 letter from Howard Runser, private citizen.
(12) August 8, 2001 letter from Brant Mannchen, Houston Regional
Group of the Sierra Club.
(13) August 13, 2001 letter from John D. Walke, Senior Attorney,
NRDC.
No comments were received on the proposed approval of the 15% ROP
plan or the proposed approval of revisions to the 1990 Base Year
Inventory. These actions are being approved with out further
discussion.

B. Response to Comments on Attainment Demonstration

1. General Comments
Comment: Several commenters urged EPA to disapprove the attainment
plan because they believe the plan does not include complete modeling,
enforceable versions of all Reasonably Available Control Measures
(RACM) and a control strategy sufficient to achieve attainment. One
commenter went on to say because they believe the plan should be
disapproved and, under the consent decree in NRDC v. Browner, Civ. No.
99-2976, EPA must commence promulgation of a Federal Implementation
Plan (FIP). One commenter supported the proposed approval.
Response: In the following responses, we address the specific
concerns raised by the commenters in more detail. We believe the plan
provided by the State of Texas is fully approvable under the Act and
will provide for attainment as expeditiously as practicable which is by
November 15, 2007 and the plan includes all reasonably available
control measures. Therefore, we are finalizing our approval in this
action. Furthermore, because we are fully approving the plan as meeting
the requirements of 182(c)(2) and (d) of the Act, it is unnecessary to
commence development of a FIP.
Comment: TNRCC has not provided modeling that shows attainment in
2007. (Really 2005 since 4 exceedences in that year ensures failure to
meet the three-year standard.) A commenter also states that there is no
demonstration of maintenance of the ozone standard below the 0.12 ppm
one-hour standard beyond 2007.
Response: EPA has taken the position that for nonattainment areas
subject to the requirements of subpart 2 of part D of the Act, that the
area needs to demonstrate that in the attainment year, the area will
have air quality such that the area could be eligible for the two one-
year extensions provided under section 181(a)(5) of the Act. Under
section 181(a)(5), an area that does not have three-years of data
demonstrating attainment of the ozone NAAQS, but has complied with all
of the statutory requirements and that has no more than one exceedance
of the NAAQS in the attainment year, may receive a one-year extension
of its attainment date. Assuming those conditions are met the following
year, the area may receive an additional one-year extension. If the
area has no more than one exceedance in this final extension year, then
it will have three-years of data indicating that it has attained the
ozone NAAQS.
This position is consistent both with EPA's modeling guidance and
with the structure of subpart 2 of the Act. Under EPA's modeling
guidance, states model air quality for the attainment year--they do not
model air quality for the three-year period preceding the attainment
year. This is largely a function of how the model operates that the
data produced only predicts the air quality for one year. EPA's
modeling guidance has existed for many years and has been relied on by
numerous areas for demonstrating attainment of the ozone standard.
Moreover, EPA believes this approach is consistent with the
statutory structure of subpart 2. Under subpart 2, many of the planning
obligations for areas were not required to be implemented until the
attainment year. Thus, Congress did not assume that all measures needed
to attain the standard would be implemented three years prior to the
area's attainment date. For example, areas classified as marginal--
which had an attainment date of three years following enactment of the
1990 Clean Air Act amendments were required to adopt and implement RACT
and I/M ``fix-ups'' that clearly could not be implemented three years
prior to their attainment date. Similarly, moderate areas were required
to implement RACT by May 1995, only 18 months prior to their attainment
date of November 1996. Also, the ROP requirement for moderate and above
areas, including the 15% plan for reductions by November 1996, applies
through the attainment year. Thus, EPA believes that Congress did not
intend that these additional mandatory reductions be in excess of what
is needed to achieve three-years of ``clean data.'' For these reasons,
EPA does not agree with the commenter that the State's attainment
demonstration needs to demonstrate that the area will have three years
of data showing attainment in the attainment year. However, EPA does
believe that the Act requires and that it is prudent for States to
implement control as expeditiously as practicable. EPA also believes
that for the HG area, all measures are being implemented as
expeditiously as practicable and that the area has

[[Page 57164]]

demonstrated attainment consistent with EPA's modeling guidance.
A plan for maintenance of the Standard is not necessary for the
attainment demonstration to be approved. A State is not required by the
Act to provide a maintenance plan until the State petitions for an area
to be redesignated to attainment which will not occur until the HG area
has three years of data showing compliance with the Standard.
While it is not necessary for the State to provide for maintenance
of the standard at this time, we do believe emissions in the HG area
will continue to decrease after 2007 due to on and off road vehicle
emission control programs that will continue to provide additional
reductions as the fleet continues to turnover after 2007. So there is
reason to believe that air quality will continue to improve after the
attainment date.
Comment: Two commenters suggested the plan should address other air
pollution concerns in addition to attainment of the one-hour standard.
One commenter suggested the plan should provide as much progress as
possible toward implementing the 8-hour standard as the requirements of
the Act and EPA's implementing regulations allow. Another commenter
said that ozone reduction should be used as a spur in reducing toxic
emissions and particulate matter as well.
Response: As an initial matter, these comments are outside the
scope of this rulemaking. EPA's review here is focused on whether the
submitted plan meets the statutory requirements for attainment of the
one-hour ozone standard. Nevertheless, EPA believes the reductions in
ozone precursors in this plan will provide reductions both toward
attainment of the one-hour standard and substantial progress toward the
8-hour standard. Furthermore, NO_X emissions are a precursor
to particulate matter formation. So the large NO_X emissions
reductions in the plan should provide improvements in particulate
matter levels. In addition, while the focus of the plan is on reducing
NO_X emissions, VOC emissions will also be reduced by
approximately 40% from 1993 levels. Some of these VOCs are also air
toxics. Again, while EPA believes these additional air quality benefits
will result from the implementation of this plan, the approval of the
plan depends, as a legal matter, only on whether the plan will result
in attainment of the one-hour ozone standard.
2. Comments on the Photochemical Modeling
a. Model Performance
Comment: The photochemical modeling is fundamentally flawed and
should not be used as proposed. The ozone plots prepared by TNRCC as
part of its graphical performance analysis show significant subregional
biases in the model with systematic under predictions and over
predictions. The commenter states that the graphical analysis provides
far more insight into the performance of the model than any other type
of performance measure. The statistical measures distort the appearance
of model performance by averaging out the subregional biases.
Response: EPA does not agree that the graphical analysis provides
more insight into model performance than any other performance
measures. EPA believes all model performance measures should be
considered. There is no rigid criterion for model acceptance or
rejection in assessing model simulation results for the performance
evaluation. As recommended by EPA, the State's model performance
evaluations for the selected episode included diagnostic and
sensitivity analyses, and graphical and statistical performance
measures. TNRCC used these performance measures in conjunction with one
another to evaluate the performance of the model. Diagnostic and
sensitivity analyses consisted of testing the response of modeled ozone
to changes in the various model inputs (i.e., meteorology, emission
inventory, and initial & boundary conditions). The model performance
evaluation was based upon graphical measures consisting of comparing
time series of monitored and modeled ozone and ozone precursor
concentrations, and comparing modeled ozone concentration contours with
monitored ozone data. The model performance evaluation was also based
upon statistical measures consisting of comparing the modeled versus
monitored ozone. The ``Unpaired Peak Accuracy,'' ``Normalized Bias,''
and, ``Gross Error'' were all within the suggested limits in the EPA
Guideline.
EPA did not dismiss any measures or analyses used by TNRCC for
their model performance evaluation, nor should EPA weigh the graphical
performance more heavily than the other performance measures. As
indicated in the State's modeling results for the selected episode, the
model responded generally as expected to the diagnostic/sensitivity
analyses for the primary episode day (9/8/93). Overall, these analyses
did not reveal any flaws in the CAMx model formulation. In addition,
the statistical performance of the model for the primary episode
indicated the model performed well. For all days modeled, the graphical
performance for the majority of the monitor sites was very good. For
instance, the time-series plots developed for each monitoring station
in the HG area indicated no significant bias within the diurnal cycle
as well as good agreement between the timing of the predicted and
observed ozone maxima.
EPA has recognized, however, the graphical model performance for
the primary episode day of 9/8/93 indicates the model at some locations
underestimated ozone and at other areas the ozone was overestimated.
Also, at some locations, there are no ozone monitors to substantiate
the model's performance. The ozone plume peaks were simulated in
different locations than occurred with the monitored results. EPA
believes that most of the error can be best explained by the
meteorological model having some difficulty in replicating the wind
speed and direction. Discrepancies in wind speed and direction not
surprisingly result in the model not predicting the maximum ozone
concentration in precisely the right location, a possibility noted by
the commenter.
TNRCC has spent considerable effort to better understand the land/
sea breeze phenomenon which has added a level of complexity to the HG
analysis not seen any where else in the country (with the exception of
some lake breeze effects in the Lake Michigan area). Emissions in the
HG area are emitted into the local atmosphere where ozone formation
begins, later emissions and ozone formed are transported out over the
warm air over the Gulf of Mexico where the warmer temperatures further
activate the chemistry to form more ozone which is then transported
back inland over the area. Current meteorological models have had
difficulty in simulating this process. We believe our understanding of
the process is sufficient, however, to interpret the photochemical
model results.
TNRCC and EPA intend to continue evaluating how to more accurately
simulate the HG area's meteorological conditions in the available
models. The need for further studies does not mean, however, that the
modeling relied upon today was unable to estimate the amount and type
of emission reductions needed for attainment. EPA believes because the
diagnostic/sensitivity tests reveal no flaws in model formulations and
the model generally predicts the right magnitude of the peak which is
confirmed by the statistical measures,

[[Page 57165]]

that the model does provide an acceptable tool for estimating the
amount of emissions reduction. It is EPA's technical opinion that based
on the weight-of-evidence and the modeling, the State's control
strategy should provide for attainment by November 15, 2007.
Any new information derived from the further studies and evaluation
will be incorporated by Texas into the SIP revision modeling to be
submitted to EPA by May 1, 2004.
Comment: EPA previously expressed its persistent concern about the
model's poor graphical performance. Now, EPA has simply ignored the
concern. The commenter quoted a previous EPA comment letter sent to the
TNRCC during the State's August 1999 public comment period for its
proposed SIP revision. EPA's comment letter stated that ``due to the
model's poor graphical performance caution is warranted in assessing
the model's projected ozone reduction due to NO_X control
strategies.''
Response: EPA disagrees that the discrepancies in graphical
performance have been ignored. Texas made numerous enhancements to its
August 1999 proposed SIP attainment demonstration modeling, based upon
EPA's comments. TNRCC has used a new version of CAMx (i.e., version
2.03), which offers several enhancements over the original version, for
the current modeling relied upon in the submitted attainment
demonstration SIP revision. Also, major improvements have been made to
the base year emission inventory. For instance, biogenic emissions and
the emissions for diesel-powered construction equipment, commercial
marine vessel emissions, airport ground support equipment emissions,
and industrial equipment emissions have been updated with more accurate
information. As a result, for all days modeled, the graphical
performance, has been improved. For instance, the time-series plots
indicate the model performance improved at a number of monitoring
stations in the HG area (i.e., Galveston site, HRM sites 3 and 4, Texas
City site and Clinton site). In addition, the statistical model
performance for the current modeling which was similar to that for the
past modeling base case indicated the model performed well. All of the
statistical parameters are within the EPA suggested limits for the
primary episode day. EPA continues to believe, taken together, the
diagnostics, sensitivity, statistical and graphical performances of the
model indicate the base case model performance is acceptable for
assessing control strategy effectiveness.
Further, in EPA's letter where we said that caution is warranted in
assessing the projected ozone reduction to NO_X control
strategies, EPA was cautioning TNRCC that sufficient NO_X
reductions should be provided to account for this uncertainty in the
model. We were not saying that the graphical performance meant the
model was unacceptable for assessing control strategy effectiveness.
Rather, we were advising the State to take into account the graphical
performance, i.e., by ensuring the control strategy took a more
conservative approach and erred on the side of caution, in the amount
of required NO_X reductions.
Comment: One commenter believes that the modeling fails to account
for ozone spikes. The TNRCC's failure to account for these spikes
necessarily means that the control strategy will not attain the
standard. Further, this results in significant over estimates of
NO_X emission reductions needed for attainment. The commenter
asserts that the spikes are caused by highly reactive VOCs, a theory it
believes to be supported by preliminary data and findings of the Texas
2000 Air Quality Study.
Response: Monitors measure concentration at a point in space, and
in reality, these concentrations can vary significantly over a grid
cell or an area. This is true especially for ozone if it is contained
in a narrow plume. Inevitably, a grid type model will smooth some
natural phenomena because natural conditions are averaged over the
volume of each grid cell. For instance, model output represents a
volume average, typically 4km x 4km by 50 meter column. As a result,
reasonable comparisons between model predictions and monitor
observations are not expected to match exactly. With reasonable
performance, time series typically show similar diurnal cycles but not
exact concentration levels. As a result, it is very difficult to obtain
a precise equality between modeled concentration and monitored
concentration. This is to be expected and does not necessarily call
into question the model's utility as a tool to predict the level of
emission reductions needed to reach attainment. As stated in previous
comments, EPA believes the model provides reasonable predictions of
ozone levels as confirmed by comparisons with monitoring data and
therefore can provide an acceptable estimate of the amount of emissions
needed for attainment. Certainly, any difficulty the model has in
replicating rapid increases in ozone, does not indicate that the model
is calling for an ``overestimate'' of the amount of NO_X
emission reductions needed for attainment. Furthermore, even if the
model is shown during the mid-course review to be overestimating the
amount of NO_X emission reductions needed for attainment, a
State is always free to adopt a control strategy that is more
stringent. See Union Electric v. EPA, 427 U.S. 246 (1976); Train v.
NRDC, 421 U.S 60 (1975).
EPA is following with interest the findings being presented from
the Texas 2000 Air Quality Study, particularly the information on
concentrations of highly reactive VOCs found in the ambient air in the
HG area. We understand Texas intends to incorporate, as much as
possible, the findings of this study into its next modeling effort,
which is currently underway and they expect to submit by the end of
2002. This study may improve our present understanding of ozone
formation in the HG area and result in an improved effectiveness of the
control strategy being implemented by the TNRCC. Nevertheless, based
upon all available evidence, the State's control strategy shows
attainment for the HG area by the statutory deadline and that the
NO_X emission reductions are needed for attainment.
Comment: The 2007 post-control strategy peak concentration is 141
ppb at a monitoring site where the model underestimated the monitored
peak by 27 ppb during the validation run. Thus, if the control strategy
had been in effect during the episode used for validating the model,
the actual ozone concentration would likely have been higher than 141
ppb.
Response: EPA disagrees. As is always the case in a photochemical
modeling exercise, there are areas within the simulation that do not
correspond exactly with observations. As discussed in other comments,
in this case, the modeled wind fields tended to move the ozone plumes
formed on all four days away from the areas where the highest
concentrations were observed. Although the modeled peak on the primary
episode day (i.e., September 8, 1993) was pushed west of the observed
peak, the results of the State's model performance evaluation analyses
for that day indicate overall the model performed well for the majority
of the monitoring sites. Misplacing the peak does not necessarily mean
the model is providing inaccurate results or predicting less ozone on
that day. In addition, this tendency does not, by itself, mean that the
model is not useful for developing control strategies. Therefore,
again, we feel the model provides a reasonable estimate of the

[[Page 57166]]

emission reductions needed for attainment.
Comment: A commenter criticized the State model's inability to
replicate ozone levels on September 8, 1993 and recommends that TNRCC
estimate the magnitude of emission reductions needed for attainment
from the modeling results of September 10 and 11, 1993. One commenter
believes the best way to manage the risks of making the wrong decision
on the magnitude of the needed controls is to base HG's control
strategy on the modeling simulations that have the least uncertainty.
Though all four days of the September 8-11, 1993 base case simulation
are characterized by poor graphical performance, the greatest
uncertainties by far exist for September 8 and 9, 1993. Therefore, the
commenter believes that the control strategy should be based on
modeling results from September 10 or 11, 1993.
Response: EPA disagrees. As discussed in previous comments, we
believe the model performance is acceptable on all four days.
Furthermore, EPA guidance recommends that a minimum of three episode
days representing different meteorological regimes be modeled(Guideline
for the Regulatory Application of the Urban Airshed Model, July 1991).
With only four days (i.e., Sept. 8-11), the number of episode days
being used by TNRCC for control strategy development is only marginally
above the recommendation. Removing days would not provide an
appropriate number of modeling days. EPA believes that the September 8,
1993 episode day chosen by TNRCC presents a reliable and accurate
modeling scenario for ozone attainment demonstration in the HG area.
September 8, 1993 is the controlling day because the meteorological
conditions experienced that day require the most control to reach
attainment. September 8, 1993 also had the highest observed ozone
during the 4 day episode. Though observed and predicted concentrations
do not match exactly, plausible inputs resulted in plausible
predictions. The overall model performance for the September 8, 1993
episode day meets EPA criteria. Model performance on September 11, 1993
was similar to that observed on September 8, 1993, but is not suitable
to design control strategies, since it was a Saturday. Controls based
on that day would still need to be shown to be effective in controlling
ozone on a weekday, since the Saturday emissions from mobile and area
sources differ considerably from their weekday counterparts.
In addition, during episode selection, TNRCC used a modification of
the Predominant Wind Direction (PWD) method to analyze each potential
episode day. The wind analysis is based on morning winds and afternoon
winds. The largest category was calm/calm with 10 of 71 cases where
most frequent wind pattern for high ozone days occurred in the HG
region. The second was calm/SSE with 9 cases. September 11, 1993 is in
this category. The third category was calm/ESE with 8 cases. September
8, 1993 is in this category. The PWD for September 10, 1993 is NNW/ESE,
which had one case. Meanwhile, the PWD for September 9, 1993 is NNW/
NNW, which had none. Therefore, each of these episode days covers
different meteorological conditions that are correlated with high ozone
levels in the HG area. To remove one or more of the four episode days
would remove conditions that should be evaluated to provide assurance
that the controls adopted in the SIP would be expected to show
attainment of the NAAQS for potential meteorological conditions
conducive to ozone formation in the HG area. In addition, September 10,
1993 had an observed peak value that was significantly lower than the
design value. Control strategies based on absolute model predictions on
this day may not be sufficient to bring the area into attainment.
Therefore, no days should be dropped from the State's attainment
demonstration.
Comment: Evaluating the equations used to estimate the shortfall
for September 10 and 11, 1993, results in gaps of 21 tpd and 37 tpd,
respectively, for which could be filled (with surplus) from the list of
gap measures given in Table 6.1-2 of the proposal.
Response: As stated in previous responses, September 8, 1993 must
be considered in the control strategy to have confidence that the HG
area will attain under a commonly observed meteorological condition. In
any case, after revisions to the inventory, modeling now indicates that
the additional reductions estimated for attainment on September 8, 1993
and September 10, 1993 is 90.9 tpd and 93.7 tpd NO_X,
respectively; thus even on September 10, 1993 the State has a shortfall
because Texas has only been able to adopt measures to achieve 38 tons/
day of additional measures.
Comment: TNRCC has presented no evidence that the model is
accurately simulating NO_X or VOC levels, or other
intermediate chemical species in the vicinity of the modeled peaks.
Response: EPA disagrees. There is no monitoring data in the area
where the modeled peak occurred to indicate one way or the other how
well the model compared to measurements of NO_X, VOC and
intermediate species. As a part of the 1993 COAST study, VOC
concentrations were measured at two locations in the HG nonattainment
area, and comparisons have been made between modeled and monitored
concentrations. Similarly, for each of the locations where
NO_X was monitored, comparisons have been made between
modeled and monitored concentrations. All of these comparisons are
included and discussed in the '98 and '99 SIPs submitted to EPA.
Therefore, the attainment demonstration we are approving relies upon
evidence that the model provided results in a reasonable agreement with
the measurements considering that the comparison is between a point
measurement and a simulated volumetric average.
Monitors measure the concentration at a point in space, and in
practice, these concentrations can vary significantly from a volume
average that is 4km square and up to 50 meter high. This is true for
VOC and NO_X precursors, and is especially true for
precursors emitted by point sources. The comparisons that have been
made indicate reasonable agreement between monitored and modeled
concentrations given the considerations cited above (see Appendix B
entitled ``Time Series Plots of Observed, CAMx and UAM-V Ozone
Precursors Over the H/G Modeling Domain for The Base Case Simulation'')
of the Appendix B (entitled ``Modeling the Houston/Galveston Ozone
Attainment Demonstration'')) of the December 2000 SIP revision.
Besides, the CAMx photochemical model, which is an ozone model, was
developed and optimized for that purpose. As expected, some other
chemical species will not compare as well with ambient data as does
ozone. As mentioned above, there are no monitoring data for
intermediate species, which have not been recommended for use in
validating model results since they are not reliable. Instead, these
are often used to validate model inputs (i.e., emission inventory), if
they become available.
Comment: Because of doubts regarding the accuracy of the model
predictions, commenters recommend that new emission controls be based
on proven cost-effective technology and that stakeholders be given as
much time to implement controls as the Act allows. The model
simulations and basic science that are the foundations of the
commission's control strategy are currently not strong enough to
support the unproven, technically infeasible, or

[[Page 57167]]

economically challenging measures in the State's adopted control
strategy.
Response: As described in previous comments, we believe that the
model performance is acceptable and provides an appropriate assessment
of the amount of emission reductions needed for the HG area to attain.
TNRCC and its contractors have used state-of-the-science approaches to
support the adopted control strategy. All appropriate and pertinent
data submitted during the State's comment periods to improve the model
were incorporated or addressed by the State. As discussed in our RACM
and the shortfall enforceable commitment responses, it is EPA's
position that the control measures in the HG control strategy are
feasible. Therefore, it is our position that the controls that have
been adopted by Texas have been shown to be needed for the HG area to
attain by the statutory deadline. These controls are being implemented
as expeditiously as practicable as required by the Act.
Comment: A commenter believes that the TNRCC must address the risk
that the modeling uncertainties may have led the commission to a wrong
estimate of the magnitude of emission reductions needed to attain the
ozone NAAQS.
Response: In the earlier submitted SIPs, the effect of the
uncertainty of the emissions relative to the reductions needed to
attain the NAAQS was addressed. This involved developing an alternate
emissions inventory that reflected uncertainties, evaluating base case
model performance, and the effect on the reductions needed to attain
the NAAQS with the future 2007 emissions. This modeling showed that the
control path needed to attain the NAAQS did not change (a
NO_X rather than VOC-directed control strategy), and that the
order of magnitude of the required reductions did not change much. This
reinforced the necessity of obtaining the level of NO_X and
VOC reductions contained in this SIP revision.
The current approach does not show attainment of the NAAQS at all
locations on all days that were modeled, but uses modeling in
combination with weight of evidence to show that this level of
NO_X and VOC reductions are adequate to attain the standard.
Furthermore, the mid-course evaluation can be used by Texas to reassess
the level of controls needed to attain the NAAQS and ensure that timely
progress is being made toward attainment of the standard.
Comment: One commenter supports the recent contract commissioned by
Harris County with Environ. This work will re-run the model with an
alternate meteorological simulation model in a further attempt to
address the non-performance of the grid cells in question.
Response: EPA understands that TNRCC has worked with Harris County
and Environ on the alternate meteorological simulation of the episode
modeled by the commission. It takes substantial time and effort to
develop meteorological data to be run in the photochemical model. After
the data are developed, the model results must be evaluated for
adequate meteorological model performance. Then the data must be used
in the photochemical model to evaluate base-case model performance with
the new data set. If the revised base case modeling meets the
performance requirements, then the model will be applied to the future
2007 emissions, and various control scenarios modeled. If these efforts
provide a better representation of meteorological conditions in the HG
area, then Texas would address them in the mid-course review.
Comment: Because of the model's performance one commenter disagrees
with the following proposals:
(1) The model activities were performed as outlined in the
Protocols.
(2) The model activities were performed according to the Guideline
For Regulatory Application of UAM.
(3) That the model performed within EPA's recommended ranges.
(4) That the base case model is suitable for control strategy
testing.
(5) The proposal to accept the base case model as a basis for
attainment demonstration modeling.
(6) The implicit finding that the TNRCC validated the performance
of the base case modeling.
(7) That the simulated ozone contour plots from the base case model
depict the area of ozone to be only ``somewhat at odds geographically''
with the monitors.
(8) The implicit finding that the base case model fails only to
``precisely predict'' the position of the cloud of ozone
geographically.
(9) That the base case model's predicted position of the cloud of
ozone does not by itself, mean that the base case model is not
acceptable for control strategy development.
(10) That the statistical measures from the base case model are
within EPA recommended limits for all days of September 8-11, 1993.
(11) That the results of the statistical measures are within EPA
recommended ranges.
(12) That the spatial and temporal patterns of ozone generated by
the base case model indicate it is acceptable for use in the Attainment
Demonstration.
(13) The diagnostic, sensitivity, statistical and graphical
performance of the base case model indicate it is acceptable for use in
the Attainment Demonstration.
(14) That reductions of NO_X will be most effective in
bringing HGA into attainment.
(15) That the quadratic equation used by the TNRCC to determine the
additional amount of additional emission reductions is consistent with
the 1999 guidance.
(16) That the quadratic equation is an improvement over the 1999
guidance.
(17) That an additional 96 tons/day of NO_X emission
reduction are necessary to bring the HG area into attainment.
Response: As discussed in previous comments, we believe the model
performed acceptably for use in control strategy development.
Therefore, we disagree with the commenter and continue to support the
findings in the conclusions from our proposed approval that are cited
above.
b. Model Inputs
Comment: Off-road shipping emissions may be underestimated based on
preliminary results from the Texas Air Quality 2000 Study.
Response: The State conducted a study of actual shipping activity
in the HG area and applied EPA emission factors to the activity to
calculate the shipping emissions. This site-specific methodology is
approved by EPA and provides the best estimate of emissions at this
time. The results from the Texas Air Quality Study 2000 are just now
being made available for analysis. The results were not available to
the State at the time the SIP was prepared, and the State needs
additional time to evaluate the data. It is hoped that the data can be
used by Texas for its mid-course review. However, there is no evidence
presently before EPA showing that off-road shipping emissions were
underestimated by the State.
Comment: Industrial VOC emissions are understated based on the
preliminary results of the Texas 2000 Air Quality Study.
Response: As discussed above, TNRCC has followed EPA approved
methodologies in preparing its emissions inventory. They have gone to
substantial effort to characterize all the categories, including the
industrial emissions. This has included detailed inventories from all
of the major emitters and inclusion of episodic releases that were
reported during the 1993 episode. We believe that the emissions
inventory is based on the best

[[Page 57168]]

available techniques and data and meets all EPA criteria and
requirements.
TNRCC is continuing to work to improve the inventory. This is a
major emphasis of the Texas 2000 Air Quality study. We are aware some
of the preliminary findings of this study indicate that industrial VOC
emissions may be understated. This indication is based upon only
preliminary findings at this time, however. Texas has reached no final
conclusions. EPA will work with TNRCC and other stakeholders to address
improvements to the inventory so that the mid-course review modeling
incorporates any new and appropriate data.
Comment: The commission and its contractors have worked commendably
to develop what may be, in many respects, the most accurate emissions
inventory ever used in photochemical modeling. But major uncertainties
still exist in other respects and in the model's representation of the
chemical reactions and meteorological processes that determine the
location, time, and magnitude of high ozone levels in Houston-
Galveston.
Response: EPA disagrees that there are major uncertainties with the
modeling. As discussed above in previous responses, it is EPA's
technical position that the modeling adequately represents the
meteorological processes for the HG area to allow its use for control
strategy purposes. Further, the modeling is acceptable in its
representation of the chemical reactions in the HG area. TNRCC and its
contractors have used state-of-the-science modeling approaches for
development of the meteorological parameters used in the modeling.
The chemical algorithms used in the modeling reflect the latest
developments in the state-of-the-science today. TNRCC is currently
investigating various alternate chemical mechanisms, and they plan to
continue this activity with analyses on the Texas 2000 study results.
If enhancements are identified for the chemical algorithms, they can be
utilized in the mid-course evaluation, and Texas would include them in
the mid-course review SIP.
Comment: It was noted that the 91 tpd increase in point source
NO_X emissions produced daily maximum ozone increases ranging
from 1.5 ppb (on September 10) to 6.1 ppb (on September 11). The
commenter also noted that the 91 tpd decrease in on-road mobile and
non-road mobile source NO_X emissions produced ozone
decreases, relative to HRM Strategy 1, ranging rom 6.9 ppb (on
September 11) to 10.8 ppb (on September 8). From this, the commenter
sees relatively small benefits from the commission's 90% point source
control proposal relative to a 75% point control level, but sees
greater benefits if the same amount of incremental emissions was
reduced from mobile sources. It was also noted that mobile source
emission reductions ranged from 1.1 to 7.0 times more effective than
point source NO_X reductions at reducing ozone levels (given
the ratio of mobile source to point source NO_X
effectiveness). From this, it follows that mobile source NO_X
emission reductions are on average 3 times more effective at reducing
ozone levels than are point source emission reductions.
Response: It is quite possible that mobile source controls may be
more effective in reducing ozone levels for certain nonattainment
areas. The State, however, analyzed the ensemble of emission reductions
modeled for the SIP development for the HG area based on an analysis of
potential reductions available from all of the various source
categories. As discussed in other sections, Texas has adopted all RACM
for mobile as well as stationary sources. It is not EPA's role to
disapprove the State's choice of control strategies if that strategy
will result in attainment of the one-hour standard and meets all other
applicable statutory requirements. See Union Electric v EPA, 427 U.S.
246 (1976); Train v. NRDC, 421 U.S 60 (1975).
Comment: One commenter states that the modeled control strategy
contained in the Attainment Demonstration includes measures that were
modified or removed from the SIP. The State did not remodel to
determine the impact of these changes. Particularly, one measure that
was modified was a relaxation in utility controls from 93% to 90%.
Another commenter supported the changes to the required emission
rates for utilities because these revisions will be offset by emission
reductions from grandfathered facilities in attainment counties
surrounding the HG area.
Response: During the State's settlement negotiations and trial
court proceedings this summer in BCCA Appeal Group, et al. v. Texas
Natural Resource Conservation Commission, et al. in the District Court
of Travis County, Texas 250th Judicial District, Cause No. GN1-00210,
TNRCC determined that the amount of control for utilities should be
reduced from 93% control to 90% control. Due to time constraints and
the necessity for submitting an approvable attainment demonstration in
time for EPA action before the NRDC consent decree deadline of October
15, 2001 for proposing a FIP in the absence of a fully approved SIP,
the revised utility controls were not modeled by TNRCC. TNRCC believes,
and EPA agrees, that any potential loss in ozone benefit from reducing
the utility point source requirement will be de minimis, based upon a
review of certain information gathered from the 2000 Texas Air Quality
Study. The information in the Study indicates that Reliant Energy's
Parish power plant, located in the HG area has an ozone production
efficiency which is 3 to 5 times smaller than the ozone production
efficiency expected for the grand-fathered utility and non-utility
sources based on Southern Oxidant Study results for the Memphis area.
Ozone production efficiency is a measure of the efficiency that a
particular NO_X plume generates ozone and is an indication of
the reactivity of the VOCs with which the NO_X plume comes in
contact. The Parish plant is located outside the central urban area and
apparently not in an area of highly reactive biogenic emissions. The
remaining units affected by the reduced control requirement are mainly
peaking units which deliver their increased emissions during the hot
afternoon hours. Modeling for the construction ban and lawn-care
activities has consistently shown that emissions in the afternoon
contribute less to ozone formation in the HG area than emissions
generated in the morning.
To counterbalance the reduced controls on utilities in the HG area,
Texas will control grandfathered sources in East and Central Texas by
50% as required by recent State legislation. These controls are in
addition to controls on utility sources, Alcoa and Texas Eastman that
are already included in the model results. These new controls would
apply to all non-utility sources, particularly pipeline compressor
station emissions would be reduced by 50%. These emission reductions
can be expected to achieve an ozone benefit in the HG area to
counterbalance the loss in NO_X reductions from the change in
utilities from 93-90% control.
Because the impact of the emission increases for utilities in the
HG area will be small and there is a program to offset these de minimis
increases, EPA believes it is appropriate to accept the modeling and
weight of evidence as showing that attainment can be achieved in the HG
area by the statutory deadline.
TNRCC currently intends to conduct modeling based on the data
results of the Texas 2000 Air Quality Study, in 2002. Pursuant to the
State's mid-course review enforceable commitment, Texas will submit a
revised attainment demonstration SIP by May 1, 2004 that

[[Page 57169]]

will include modeling that incorporates all scientific advancements
made since the recent SIP revisions, as appropriate.
Comment: As required by recent legislation, the TNRCC repealed the
time-of-day construction ban. To provide for the benefits that would
have been achieved by the construction ban, the Texas legislature
adopted a diesel emission reduction incentive program. However, TNRCC
failed to model the control strategy with the diesel engine incentive
program replacing the morning construction ban. EPA may not approve the
photochemical modeling and the subsequent gap calculation because these
emission reductions were revised and not modeled.
Response: Texas legislation, enacted in May, 2001, established a
diesel emission reduction incentive program and required TNRCC to
repeal its rules for a morning construction ban and accelerated
purchase of diesel equipment. Due to time constraints and the necessity
for submitting an approvable attainment demonstration in time for EPA
action before the NRDC consent decree deadline of October 15, 2001 for
proposing a FIP in the absence of a fully approved SIP, the State could
not specifically model the diesel engine incentive program in their
attainment demonstration. The TNRCC had, however, conducted numerous
control scenario modeling runs, which combined federal, state and local
measures, designed to provide significant ozone reductions in the area.
The results of one control scenario modeling run indicated that the
benefit of the construction ban was approximately 3 ppb of ozone. Based
on the quadratic curve, TNRCC estimated that this 3 ppb reduction in
the ozone concentration level was equivalent to a 6.7 tpd reduction of
NO_X emissions. EPA believes the State used acceptable
procedures for determining this estimate. As discussed in other
responses to comments regarding the diesel engine incentive Program,
EPA believes that this program will achieve greater NO_X
emission reductions in the HG area than 6.7 tpd. EPA and State
calculations project that this new program will cover the loss in
reductions from the construction ban and the accelerated purchase
rules, and also fill a portion of the shortfall. EPA believes that the
incentive program will likely produce somewhat greater benefits than
the morning construction ban because it can achieve emission reductions
not only from construction diesel equipment but also from additional
categories such as tug/tow boats which are located in the portion of
the HG area where the highest ozone levels often occur. In addition,
TNRCC currently intends to conduct modeling based on the data results
of the 2000 Texas Air Quality Study, in 2002. Pursuant to the State's
mid-course review enforceable commitment, Texas will submit a revised
attainment demonstration SIP by May 1, 2004 that will include modeling
that incorporates all scientific advancements made since the recent SIP
revisions, as appropriate.
Comment: TNRCC has not correctly estimated point source growth in
attainment counties of East and Central Texas. The commenter provided
Public Utility Commission estimates of new capacity.
Response: As noted by the commenter, Appendix H of the SIP contains
documentation of the projected newly permitted growth. Texas examined
all of the permits issued by TNRCC for the 8 county HG area and the
counties within 100 miles of the HG area. Permitted projects in this
area were included in the model's future base inventory. EPA believes
that Texas used a reasonable method of estimating the growth for the
area most likely to impact the HG area's air quality.
Comment: One commenter stated the attainment and rate of progress
demonstrations are flawed because they assume a fleet mix that does not
accurately reflect the growing proportion of sport utility vehicles and
gasoline trucks. EPA and the states have not followed a consistent
practice in updating SIP modeling to account for changes in vehicle
fleets. EPA cannot rationally approve SIPs that are based on such
materially inaccurate assumptions. Continued use of out-dated
assumptions is inconsistent with the duty imposed by the Act section
182(a)(3) to triennially update the emission inventory. If the motor
vehicle inventory has not been updated in preparing the current SIP
submission, the SIP should be disapproved. One commenter compared the
numbers from the Dallas/Fort Worth area to the HG area and provided the
results of a Contractor Study of vehicle registration data to support
its claims that the portion of SUVs in the Houston fleet are
understated.
Response: The November 1999 HG area attainment demonstration SIP's
associated mobile source budgets were based on fleet mix information
updated based on a December 1998 Texas Transportation Institute (TTI)
Report, ``Development of Gridded On-road Inventory for the Houston/
Galveston Ozone Nonattainment Area,'' found in Appendix G of the
November 1999 SIP revision. TTI relied on vehicle classification count
data recorded on roadways throughout the 8-county area by Texas
Department of Transportation (TxDOT) personnel utilizing automatic
vehicle classification (AVC) equipment. This equipment is set up along
the roadway and is calibrated to classify all of the passing vehicles
into thirteen vehicle types. Due to the fact that AVC equipment cannot
distinguish vehicle fuel type on the roadway, the various vehicle
categories are then separated out into their gasoline and diesel
classifications, based on a combination of MOBILE5 defaults and county
vehicle registration data. The fleet mix information was based on
vehicle counts that were a mix of 1996 data for week days, and 1993 and
1998 data for weekends. This was the most recent data available when
Texas submitted the attainment demonstration SIP for the HG area in
November 1999.
The December 2000 SIP included data provided by TTI from the most
recently available observed AVC data which was from 1997, 1998, and
1999. In order to avoid year-to-year fluctuations in the data set, TTI
averaged the AVC data from these three years in order to obtain a more
recent VMT mix, which was used in the revised 2007 inventory. This data
was used to update the modeling provided in December 2000. At the time
the TNRCC modeling for the December 2000 SIP was being completed, this
data set was the most recent data available. The data used for the
modeling is more recent than the most recently completed periodic
inventory (1996). The 1999 inventory is expected to be completed soon
and include the more recent data.
EPA requires the most recent available data to be used, but we do
not require it to be updated on a specific schedule. Therefore,
different SIPs base their fleet mix on different years of data. Our
guidance does not suggest that SIPs should be disapproved on this
basis. Nevertheless, we do expect that revisions to these SIPs that are
submitted using MOBILE6 (as required in those cases where the SIP is
relying on emissions reductions from the Tier 2 standards) will use
updated vehicle registration data appropriate for use with MOBILE6,
whether it is updated local data or the updated national default data
that will be part of MOBILE6.
In the November 3, 1999, ``Guidance on Motor Vehicle Emissions
Budgets in One-Hour Ozone Attainment Demonstrations,'' we state that,
when developing motor vehicle emissions budgets, the MOBILE inputs
(including vehicle fleet characteristics) should be appropriate and up-
to-date as outlined in EPA's guidance on SIP inventories and the MOBILE
user's guide. The SIP

[[Page 57170]]

has been based on the most recent information and meets the intended
purpose of the existing guidance.
A particular concern raised by a commenter was that registration
data from the TXDOT data base indicate that 13.2% of the vehicles
registered in the 8 county area are light duty gas trucks two (LDGT2)
as compared to the VMT mix figures provided by TTI which project this
category at only 4.5% of the mix. The commenter also pointed out that
LDGT2 were estimated as 11.4% of the mix for the Dallas/Fort Worth area
SIP and the EPA national default is 8.8%. The LDGT2 category includes
large SUV and pickups. The percentage of miles traveled by these
vehicles is important because they currently have higher emission
standards than passenger cars.
The EPA believes that vehicle registration data alone does not
necessarily represent the most accurate estimation of fleet mix
characteristics that actually exist on the current transportation
network system. The best possible approach would be to use a
combination of both AVC and conventional registration data. However,
EPA believes that field AVC data of vehicles traveling on the roadways
throughout the 8-county area provide a reasonable estimate of the types
of vehicles and distance these vehicles are driven. This is because
vehicles from some categories are driven more than other categories.
Heavy Duty Diesel Trucks, in particular, account for more miles than
the values that may be reflected by the vehicular registration process.
Registration distribution is different than VMT mix and actual data is
the best possible information. In addition, while one might expect the
numbers to be similar between DFW and Houston, they are two different
cities with many different social and economic variables. One cannot
presume Houston to be the same as DFW when the location specific data
does not support this conclusion.
It is worth noting that the Tier II standards will eliminate the
difference between (i) passenger car and (ii) larger truck and SUV
emissions standards. Therefore, as Tier II vehicles become more
widespread, possible discrepancies in the percentage of trucks and SUVs
will become less important for air quality planning purposes. The Tier
II standards begin taking affect in new vehicle manufactured in 2004.
The EPA has encouraged and required use of the latest assumptions
and data in forecasting the on-road mobile source emissions whenever
possible. Updating the data and using the latest information is a
continuous planning process which does not end with this SIP and will
continue in the future for emissions inventory updates, SIP
development, and for conducting conformity determinations. In addition,
the refinements in the emissions inventory procedures and use of the
MOBILE6 model will further enhance not only the VMT mix issue but also
other parametric inputs in computing the on-road mobile source
emissions. However, it must be recognized that because of many
constraints associated with availability and timing of new information,
the process of updating the vehicular and other data does not
necessarily follow the SIP development cycle, and thus there is likely
to be a lag time. The EPA is committed to ensure that the best
available data are used in any air quality analysis and this SIP is no
exception. Therefore, based on the information documented in the SIP
and the EPA's current guidance, the EPA believes that Texas has made
reasonable assumptions and has utilized the most recent available data
in determining the on-road mobile source emissions.
Comment: The model's failure to account for episodic emissions
events is a serious flaw. The commenter cited a description in the SIP
of a butadiene release as evidence of this problem.
Response: TNRCC made every effort to account for episodic emissions
in the model. It surveyed companies to determine if any specific events
occurred during the modeling episode, including reported upset events.
The reported episodic emissions were included in the modeling.
Consequently, we believe Texas used the best information available to
address episodic emissions and therefore, the SIP is approvable.
The growing availability of ambient VOC data from the Photochemical
Assessment Monitoring Stations (PAMS) network, however, indicates that
more may need to be done in this area. The butadiene release cited by
the commenter is a case in point. In addition, the Texas 2000 Air
Quality Study is providing a wealth of information that is just being
analyzed. This data, it is hoped, will shed more light on the impact of
episodic emissions on ozone levels. The mid-course review SIP, due to
EPA in May 2004, will contain the most recent data available for that
SIP's planning.
Comment: EPA should investigate the impact on the plan of any
changes being considered in the EPA's 90-day review of the New Source
Review (NSR) progam. The commenter is concerned that relaxed NSR
requirements may affect the level of emissions from point sources in
the Region.
Response: The 90-day review of the NSR program is not complete at
this time. It is expected that any modifications to the Federal NSR
provisions will include provisions for strict caps for the pollutants
and therefore should be as stringent as the present NSR rule. Moreover,
any changes made through this review will not affect the NSR rules
approved for the HG area in the current SIP. If Texas determines that
the HG area rules should be modified in response to the 90-day review,
Texas will need to submit those changes as a SIP revision and under
Section 110(l) of the Act, EPA will need to consider the effect of
those changes on the HG area's attainment demonstration.
c. Weight of Evidence Analysis
Comment: Several commenters stated that the weight of evidence
approach does not demonstrate attainment or meet CAA requirements for a
modeled attainment demonstration. Commenters added several criticisms
of various technical aspects of the weight of evidence approach,
including certain specific applications of the approach to particular
attainment demonstrations. These comments are discussed in the
following response.
Response: Under section 182(c)(2) and (d) of the Act, serious and
severe ozone nonattainment areas were required to submit by November
15, 1994, demonstrations of how they would attain the one-hour
standard. Section 182(c)(2)(A) provides that ``[t]his attainment
demonstration must be based on photochemical grid modeling or any other
analytical method determined by the Administrator, in the
Administrator's discretion, to be at least as effective.'' As described
in more detail below, the EPA allows states to supplement their
photochemical modeling results, with additional evidence designed to
account for uncertainties in the photochemical modeling, to demonstrate
attainment. This approach is consistent with the requirement of section
182(c)(2)(A) that the attainment demonstration ``be based on
photochemical grid modeling,'' because the modeling results constitute
the principal component of EPA's analysis, with supplemental
information designed to account for uncertainties in the model. This
interpretation and application of the photochemical modeling
requirement of section 182(c)(2)(A) finds further justification in the
broad deference Congress granted EPA to develop appropriate methods for

[[Page 57171]]

determining attainment, as indicated in the last phrase of section
182(c)(2)(A).
The flexibility granted to EPA under section 182(c)(2)(A) is
reflected in the regulations EPA promulgated for modeled attainment
demonstrations. These regulations provide, ``The adequacy of a control
strategy shall be demonstrated by means of applicable air quality
models, data bases, and other requirements specified in (40 CFR part
51, Appendix W) (Guideline on Air Quality Models).''\1\ 40 CFR
51.112(a)(1). However, the regulations further provide, ``Where an air
quality model specified in appendix W. * * * is inappropriate, the
model may be modified or another model substituted (with approval by
EPA, and after) notice and opportunity for public comment. * * *.''
Appendix W, in turn, provides that, ``The Urban Airshed Model (UAM) is
recommended for photochemical or reactive pollutant modeling
applications involving entire urban areas,'' but further refers to
EPA's modeling guidance for data requirements and procedures for
operating the model. 40 CFR part 51, Appendix W, section 6.2.1.a. The
modeling guidance discusses the data requirements and operating
procedures, as well as interpretation of model results as they relate
to the attainment demonstration. This provision references guidance
published in 1991, but EPA envisioned the guidance would change as we
gained experience with model applications, which is why the guidance is
referenced, but does not appear, in Appendix W. With updates in 1996
and 1999, the evolution of EPA's guidance has led us to use both the
photochemical grid model, and additional analytical methods approved by
EPA.
---------------------------------------------------------------------------

\1\ The August 12, 1996 version of ``Appendix W to Part 51--
Guideline on air Quality Models'' was the rule in effect for these
attainment demonstrations. EPA is proposing updates to this rule
which will not be in effect until the new rule is promulgated.
---------------------------------------------------------------------------

The modeled attainment test compares model predicted one-hour daily
maximum ozone concentrations in all grid cells for the attainment year
to the level of the NAAQS. The results may be interpreted through
either of two modeled attainment or exceedance tests: A deterministic
test or a statistical test. Under the deterministic test, a predicted
concentration above 0.124 parts per million (ppm) ozone indicates that
the area is expected to exceed the standard in the attainment year and
a prediction at or below 0.124 ppm indicates that the area is expected
to not exceed the standard. Under the statistical test, attainment is
demonstrated when all predicted (i.e., modeled) one hour ozone
concentrations inside the modeling domain are at, or below, an
acceptable upper limit above the NAAQS permitted under certain
conditions (depending on the severity of the episode modeled).\2\
---------------------------------------------------------------------------

\2\ Guidance on the Use Of Modeled Results to Demonstrate
Attainment of the Ozone NAAQS. EPA-454/B-95-007, June 1996.
---------------------------------------------------------------------------

In 1996, EPA issued guidance\3\ to update the 1991 guidance
referenced in 40 CFR part 50, App. W, to make the modeled attainment
test more closely reflect the form of the NAAQS (i.e., the statistical
test described above), to consider the area's ozone design value and
the meteorological conditions accompanying observed exceedances, and to
allow consideration of other evidence to address uncertainties in the
modeling databases and application. When the modeling does not
conclusively demonstrate attainment, EPA has concluded that additional
analyses may be presented to help determine whether the area will
attain the standard. As with other predictive tools, there are inherent
uncertainties associated with air quality modeling and its results. The
inherent imprecision of the model means that it may be inappropriate to
view the specific numerical result of the model as the only determinant
of whether the SIP controls are likely to lead to attainment. The EPA's
guidance recognizes these limitations, and provides a means for
considering other evidence to help assess whether attainment of the
NAAQS is likely to be achieved. The process by which this is done is
called a weight of evidence determination. Under a weight of evidence
determination, the state can rely on, and EPA will consider in addition
to the results of the modeled attainment test, other factors such as
other modeled output (e.g., changes in the predicted frequency and
pervasiveness of one-hour ozone NAAQS exceedances, and predicted change
in the ozone design value); actual observed air quality trends (i.e.
analyses of monitored air quality data); estimated emissions trends;
and the responsiveness of the model predictions to further controls.
---------------------------------------------------------------------------

\3\ Ibid.
---------------------------------------------------------------------------

In 1999, EPA issued additional guidance \4-5\ that makes further
use of model results for base case and future emission estimates to
predict a future design value. This guidance describes the use of an
additional component of the weight of evidence determination, which
requires, under certain circumstances, additional emission reductions
that are or will be approved into the SIP, but that were not included
in the modeling analysis, that will further reduce the modeled design
value. An area is considered to monitor attainment if each monitor site
has air quality observed ozone design values (4th highest daily maximum
ozone using the three most recent consecutive years of data) at or
below the level of the standard. Therefore, it is appropriate for EPA,
when making a determination that a control strategy will provide for
attainment, to determine whether or not the model predicted future
design value is expected to be at or below the level of the standard.
Since the form of the one-hour NAAQS allows exceedances, it did not
seem appropriate for EPA to require the test for attainment to be ``no
exceedances'' in the future model predictions. The method outlined in
EPA's 1999 guidance uses the highest measured design value from all
sites in the nonattainment area for each of three years.\6\ The three
year ``design value'' represents the air quality observed during the
time period used to predict ozone for the base emissions. This is
appropriate because the model is predicting the change in ozone from
the base period to the future attainment date. The three yearly design
values (highest across the area) are averaged to account for annual
fluctuations in meteorology. The result is an estimate of an area's
base year design value. The base year design value is multiplied by a
ratio of the peak model predicted ozone concentrations in the
attainment year (i.e., average of daily maximum concentrations from all
days modeled) to the peak model predicted ozone concentrations in the
base year (i.e., average of daily maximum

[[Page 57172]]

concentrations from all days modeled). The result is an attainment year
design value based on the relative change in peak model predicted ozone
concentrations from the base year to the attainment year. Modeling
results also show that emission control strategies designed to reduce
areas of peak ozone concentrations generally result in similar ozone
reductions in all core areas of the modeling domain, thereby providing
some assurance of attainment at all monitors.
---------------------------------------------------------------------------

\4\ \5\ ``Guidance for Improving weight of Evidence Through
Identification of Additional Emission Reductions, Not Modeled.''
U.S. Environmental Protection Agency, Office of Air Quality Planning
and Standards, Emissions, Monitoring, and Analysis Division, Air
Quality Modeling Group, Research Triangle Park, NC 27711. November
1999. Web site: http://www.epa.gov/ttn/scram. http://
www.ncdc.noaa.gov/ol/climate/research/1999/perspectives.html and
``Regional Haze and Visibility in the Northeast U.S.'', NESCAUM at
http://bronze.nescaum.org/regionalhaze/Final_Report.pdf
\6\ A commenter criticized the 1999 guidance as flawed on
grounds that it allows the averaging of the three highest air
quality sites across a region, whereas EPA's 1991 and 1996 modeling
guidance requires that attainment be demonstrated at each site. This
has the effect of allowing lower air quality concentrations to be
averaged against higher concentrations thus reducing the total
emission reduction needed to attain at the higher site. The
commenter's concern is misplaced. EPA relies on this averaging only
for purposes of determining one component, i.e.,--the amount of
additional emission reductions not modeled--of the weight of
evidence determination. The weight of evidence determination, in
turn, is intended to be a qualitative assessment of whether
additional factors (including the additional emissions reductions
not modeled), taken as a whole, indicate that the area is more
likely than not to attain.
---------------------------------------------------------------------------

In the event that the attainment year design value is above the
standard, the 1999 guidance provides a method for identifying
additional emission reductions, not modeled, which at a minimum provide
an estimated attainment year design value at the level of the standard.
This step uses a locally derived factor which assumes a relationship
between ozone and the precursors.
Although a commenter criticized this technique for estimating
ambient improvement because it does not incorporate complete modeling
of the additional emissions reductions, the regulations do not mandate
nor does EPA guidance suggest that States must model all control
measures being implemented. Moreover, a component of this technique-the
estimation of future design value, should be considered a model
predicted estimate. Therefore, results from this technique are an
extension of ``photochemical grid'' modeling and are consistent with
section 182(c)(2)(A). Also, a commenter believes EPA has not provided
sufficient opportunity to evaluate the calculations used to estimate
additional emission reductions. EPA provided a 60-day period for
comment on the methodology and calculations in December 1999 and a 30-
day comment period in July 2001 on the HG area's calculated shortfall.
Texas also provided a public comment period and public hearings in
September, 2000 on this issue.
A commenter states that application of the method of attainment
analysis used for the December 16, 1999 NPRs will yield a lower control
estimate than if we relied entirely on reducing maximum predictions in
every grid cell to less than or equal to 124 ppb on every modeled day.
However, the commenter's approach may overestimate needed controls
because the form of the standard allows up to 3 exceedances in 3 years
in every grid cell. If the model over predicts observed concentrations,
predicted controls may be further overestimated. EPA has considered
other evidence, as described above through the weight of evidence
determination.
When reviewing a SIP, the EPA must make a reasonable determination
that the control measures adopted more likely than not will lead to
attainment. Under the Weight of evidence determination, EPA has made
this determination for the HG area based on all of the information
presented by the State and available to EPA. The information considered
includes model results for the majority of the control measures. Though
all measures were not modeled, EPA reviewed the model's response to
changes in emissions as well as observed air quality changes to
evaluate the impact of additional measures, not modeled. EPA's decision
was further strengthened by the State's commitment to check progress
towards attainment in 2004 and to adopt additional measures, if the
anticipated progress is not being made.
A commenter further criticized EPA's technique for estimating the
ambient impact of additional emissions reductions not modeled on
grounds that EPA employed a rollback modeling technique that, according
to the commenter, is precluded under EPA regulations. The commenter
explained that 40 CFR part 51, App. W, section 6.2.1.e. provides,
``Proportional (rollback/forward) modeling is not an acceptable
procedure for evaluating ozone control strategies.'' Section 14.0 of
appendix W defines ``rollback'' as ``a simple model that assumes that
if emissions from each source affecting a given receptor are decreased
by the same percentage, ambient air quality concentrations decrease
proportionately.'' Under this approach if 20% improvement in ozone is
needed for the area to reach attainment, it is assumed a 20% reduction
in VOC would be required.
The ``proportional rollback'' approach is based on a purely
empirically/mathematically derived relationship. EPA did not rely on
this approach in its evaluation of the attainment demonstrations. The
prohibition in Appendix W applies to the use of a rollback method which
is empirically/mathematically derived and independent of model
estimates or observed air quality and emissions changes as the sole
method for evaluating control strategies. For the demonstrations, EPA
used a locally derived (as determined by the model and/or observed
changes in air quality) relationship of the change in emissions to
change in ozone to estimate additional emission reductions to achieve
an additional increment of ambient improvement in ozone. For example,
if monitoring or modeling results indicate that ozone was reduced by 25
ppb during a particular period, and that VOC and NO_X
emissions fell by 20 tons per day and 10 tons per day respectively
during that period, EPA developed a relationship for ozone improvement
related to reductions in VOC and NO_X. This formula assumes a
quadratic relationship between the precursors and ozone for a small
amount of ozone improvement, but it is not a ``proportional rollback''
technique. Further, EPA uses these locally derived adjustment factors
as a component to estimate the extent to which additional emissions
reductions--not the core control strategies--would reduce ozone levels
and thereby strengthen the weight of evidence test. EPA uses the UAM to
evaluate the core control strategies. This limited use of adjustment
factors is more technically sound than the unacceptable use of
proportional rollback to determine the ambient impact of the entire set
of emissions reductions required under the attainment SIP. The limited
use of adjustment factors is acceptable for practical reasons: It
obviates the need to expend more time and resources to perform
additional modeling. In addition, the adjustment factor is a locally
derived relationship between ozone and its precursors based on air
quality observations and/or modeling which is more consistent with
recommendations referenced to in Appendix W and does not assume a
direct proportional relationship between ozone and its precursors. In
addition, the requirement that areas perform a mid-course review (a
check of progress toward attainment) provides a margin of safety.
A commenter expressed concerns that EPA used a modeling technique
(proportional rollback) that was expressly prohibited by 40 CFR part
51, Appendix W, without expressly proposing to do so in a notice of
proposed rulemaking. However, the commenter is mistaken. As explained
above, EPA did not use or rely upon a proportional rollback technique
in this rulemaking, but used UAM to evaluate the core control
strategies and then applied its WOE guidance. Therefore, because EPA
did not use an ``alternative model'' to UAM, it did not trigger an
obligation to modify Appendix W. Furthermore, EPA did propose to use
the November 1999 guidance, ``Guidance for Improving Weight of Evidence
Through Identification of Additional Emission Reductions, Not
Modeled,'' in the December 16, 1999 NPR and has responded to all
comments received on the application of that guidance elsewhere in this
document.

[[Page 57173]]

A commenter also expressed concern that EPA applied unacceptably
broad discretion in fashioning and applying the WOE determinations. For
all of the attainment submittals proposed for approval in December 1999
concerning serious and severe ozone nonattainment areas, EPA first
reviewed the UAM results. In all cases, the UAM results did not pass
the deterministic test. In two cases--Milwaukee and Chicago--the UAM
results passed the statistical test; in the rest of the cases, the UAM
results failed the statistical test. The UAM has inherent limitations
that, in EPA's view, were manifest in all these cases. These
limitations include: Only selected time periods were modeled, not the
entire three-year period used as the definitive means for determining
an area's attainment status. Also, there are inherent uncertainties in
the model formulation and model inputs such as hourly emission
estimates, emissions growth projections, biogenic emission estimates,
and derived wind speeds and directions. As a result, for all areas,
even Milwaukee and Chicago, EPA examined additional analyses to
indicate whether additional SIP controls would yield meaningful
reductions in ozone values. These analyses did not point to the need
for additional emission reductions for Springfield, Greater
Connecticut, Metropolitan Washington DC, Chicago and Milwaukee, but did
point to the need for additional reductions, in varying amounts, in the
other areas. As a result, the other areas submitted control
requirements to provide the indicated level of emissions reductions.
EPA applied consistent methodologies in these areas, but because of
differences in the application of the model to the circumstances of
each individual area, the results differed on a case-by-case basis.
The commenter also complained that EPA has applied the WOE
determinations to adjust modeling results only when those results
indicate nonattainment, and not when they indicate attainment. First,
we disagree with the premise of this comment: EPA does not apply the
WOE factors to adjust model results. EPA applies the WOE factors as
additional analysis to compensate for uncertainty in the air quality
modeling. Second, EPA has applied WOE determinations to all of the
attainment demonstrations proposed for approval in December 1999.
Although for most of them, the air quality modeling results by
themselves indicated nonattainment, for two metropolitan areas--Chicago
and Milwaukee, including parts of the States of Illinois, Indiana, and
Wisconsin, the air quality modeling did indicate attainment on the
basis of the statistical test.
For the HG area, the primary evidence, in addition to the modeled
control strategy that the HG area will attain the standard, is the
estimation of the ozone benefits from the emission reductions that were
not modeled (i.e., approximately 90.9 tpd). Additional evidence for the
HG area is provided by the good model performance which lends credence
to the results. Further evidence is the substantial reduction in the
area of nonattainment projected for the control strategy case. The
State showed the modeled control strategy resulted in a 93.6% reduction
in grid cells over the standard. Finally, the state's commitment to
perform a mid-course review provides further confidence that the
State's overall plan will result in attainment by 2007. Collectively,
the above information supported EPA's decision. These determinations
were made based on EPA's best understanding of the problem and relied
on a qualitative assessment as well as quantitative assessments of the
available information.
The commenter further criticized EPA's application of the weight of
evidence determination on grounds that EPA ignores evidence indicating
that continued nonattainment is likely, such as, according to the
commenter, monitoring data indicate that ozone levels in many cities
during 1999 continue to exceed the NAAQS by margins as wide or wider
than those predicted by the UAM model. EPA did consider the monitoring
data along with other information in these determinations. When
reviewing the monitoring data, EPA considered other factors. For
example, high monitoring values may have occurred for many reasons
including, fluctuations due to changes in meteorology and lack of
emission reductions. The 1999 monitor values do not reflect several
control programs, both local and the regional which are scheduled for
implementation in the next several years. And the 1999 meteorology in
the Northeast was such that July 1999 was one of the warmest (ranked
9th) ever experienced since 1895.\7\ In addition to the heat, the
middle and southern portions of the Northeast were also drier than
average during this month. This information supports EPA's belief that
the high exceedances observed in 1999 are not likely to reoccur
frequent enough to cause a violation, once the controls adopted in
these SIP's are implemented. There is little evidence to support the
statement that ozone levels in many cities during 1999 continue to
exceed the NAAQS by margins as wide or wider than those predicted by
the UAM. Since areas did not model 1999 ozone levels using 1999
meteorology and 1999 emissions which reflect reductions anticipated by
control measures, that are or will be approved into the SIP, there is
no way to determine how the UAM predictions for 1999 compare to the
1999 air quality. Therefore, we can not determine whether or not the
monitor values exceed the NAAQS by a wider margin than the UAM
predictions for 1999. In summary, there is little evidence to support
the conclusion that high exceedances in 1999 will continue to occur
after adopted control measures are implemented.
---------------------------------------------------------------------------

\7\ http://www.ncdc.noaa.gov/ol/climate/research/1999/
perspectives.html and ``Regional Haze and Visibility in the
Northeast U.S.'', NESCAUM at http://bronze.nescaum.org/regionalhaze/
Final_Report.pdf
---------------------------------------------------------------------------

In addition, the commenter argued that in applying the weight of
evidence determinations, EPA ignored factors showing that the SIPs
under-predict future emissions, and the commenter included as examples
certain mobile source emissions sub-inventories. EPA did not ignore
possible under-prediction in mobile emissions. EPA is presently
evaluating mobile source emissions data as part of an effort to update
the computer model for estimating mobile source emissions. EPA is
considering various changes to the model, and is not prepared to
conclude at this time that the net effect of all these various changes
would be to increase or decrease emissions estimates. For the HG area's
attainment demonstration SIP that relies on the Tier 2/Sulfur program
for attainment (and reflects these programs in its motor vehicle
emissions budgets), Texas has committed to revise the motor vehicle
emissions budgets after the MOBILE6 model is officially released by
EPA. EPA will work with Texas if the new emission estimates raise
issues about the sufficiency of the present attainment demonstration.
If analysis indicates additional measures are needed, EPA will take
appropriate action.
Comment: The 1999 Guidance Document was criticized on grounds that
EPA could not apply it, by its terms, to the Houston area because the
result of such application would have been absurd. The commenter added
that the technique used to estimate the additional needed emission
reductions for the Houston area does not identify a sufficient level of
emission reductions to reach attainment. In addition, according to the
commenter, the

[[Page 57174]]

technique used for the Houston area is substantially at variance with
the UAM modeling analyses performed by Texas and submitted to EPA as
SIP revisions. Specifically, Texas showed in its May 1998 SIP
submission that emissions in the Houston area would have to be reduced
to 230 tons per day to attain. By contrast, according to the commenter,
EPA's combination of techniques would allow 305 tons per day of
emissions, and yet EPA claims that the area will attain with even this
higher level of emissions. The commenters believe that Texas should not
be able to use the gap calculation when modeling exists that
demonstrates how attainment can be achieved. A commenter also asserted
that Texas should not be able to use a gap calculation method that
differs from what other areas must use and the gap calculation fails to
account for real world chemistry.
Response: Direct application of the two methods discussed in EPA's
November 1999 guidance, using available data for the HG area, produced
a mathematical impossibility. The results indicated that all ozone
precursor emissions would have to be reduced to less than zero. Thus,
the two methods described in the 1999 guidance are not directly
applicable to Houston. The 1999 guidance describes two techniques for
estimating additional levels of emission reductions. Both techniques
(methods) described in the 1999 guidance are based on the assumption
that EPA can estimate the relationship between ozone and its
precursors. EPA Region 6 and TNRCC worked together to develop a revised
method that is consistent with the concepts in the 1999 guidance for
estimating the relationship, but applicable to the Houston area's
modeling results. The methods in the guidance use a linear
extrapolation of model results to determine expected ozone benefits
from additional precursor reductions. The method for the HG area is
also an extrapolation of model results. Because, the method for the HG
area extends model results, it does, in fact account for real world
chemistry. Instead of a linear extrapolation, however, a quadratic
extrapolation was developed based on the results of three of the
modeling runs. A quadratic extrapolation is necessary because of the
non-linearity of the ozone response to NO_X reductions in the
HG area. Therefore, the method is a refinement in the methods described
in the 1999 guidance, since it is based on the most recently available
modeling for the Houston area. The factors used in the method for the
Houston area are based on model results for the majority of the control
measures and, consequently, are scientifically sound for the HG area.
We believe this approach is consistent with the intent and criteria of
the 1999 guidance and, in the case of the Houston area, gives a better
approximation (than the other two methods) of the amount of emission
reductions that will be necessary to achieve the standard. Therefore,
this method fulfills the purposes of the EPA guidance, and it is as
rigorous, if not more rigorous, than the two methods discussed in the
1999 guidance. As a result, EPA concludes that the State of Texas used
an acceptable method under the November 1999 guidance and applied it
correctly.
In the strategy upon which the NO_X mobile vehicle
emissions budget is based, Texas modeled NO_X emissions
reduced to a level of approximately 396 t/d. Since the model predicted
future ozone design values above the standard, using the refinement of
the 1999 guidance (discussed above) EPA determined additional emission
reductions were needed and the level of NO_X needed for
attainment is 305 t/d.
The 230 tons per day emission level in the May 1998 SIP submission
was based upon ``across-the-board'' emission sensitivity modeling and
not specific control measures, as was submitted in the November 1999
attainment demonstration. Thus, the 230 tons per day emission level is
not associated with any control measures, and it is not appropriate as
a regulatory emission level for an attainment SIP. In addition, there
have been many notable changes to the modeling emissions inventory
subsequent to the May 1998 SIP submission. These include revised
biogenic emissions, revised non-road emissions, and revised 2007 future
year on-road mobile source emissions. Thus, it is not appropriate to
compare the 305 t/d and the 230 t/d, since they are really based upon
different applications of the model. Further, it is not correct to say
modeling exist that demonstrates how attainment can be achieved.
With regards to whether the approach used for the HG area
sufficiently identifies the expected additional amount of emission
reductions needed for attainment by the deadline, for the reasons noted
above, we believe the modeling and weight of evidence techniques used
for the HG area do provide a reasonable estimate of the emission
reductions necessary for attainment. Furthermore, these emission
reductions are quite substantial. The projected attainment level of 305
t/d of NO_X is a 71% reduction from the projected 2007
NO_X emissions of 1052 t/d and a 77% reduction from the 1993
NO_X emissions of 1337 t/d. This is a significant amount of
NO_X reductions and based on the analyses presented, EPA
believes these level of reductions will bring the area into attainment.
Comment: A commenter stated that TNRCC took into account modeling
performance concerns in developing a weight of evidence analysis to
support its October 1999 SIP revision and concluded that a modeled
control strategy, nearly identical to the one described in its December
2000 SIP revision would produce attainment even though attainment was
not conclusively demonstrated by the model. EPA rejected this analysis,
however, and prescribed a new method that the commenter goes on to
criticize.
Response: EPA did not believe that sufficient emission reductions
had been identified in the control strategy modeled in the November
1999 episode. EPA proposed its preliminary analysis of the November
1999 SIP revision that a shortfall of 11% NO_X emission
reduction existed. Significantly, we received no comments at the time
of that proposal that the 11% shortfall was too high. We received
comments to the contrary that the needed additional emission reductions
were understated.
EPA does not agree with the characterization that EPA
``prescribed'' a new method. Other weight of evidence techniques, as
described in EPA guidance were still available to Texas and could have
been considered. We worked with Texas in the development of the
quadratic method that was used as weight of evidence for the HG area to
provide a method that we and Texas believed gave an accurate estimate
of the needed additional emission reductions.
Comment: A commenter criticizes that in contrast to the 1999
Guidance, the weight of evidence method EPA developed for the HGA does
not employ a relative reduction factor or a future design value
calculation. The quadratic extrapolation is neither consistent with nor
an improvement on the 1999 guideline methods and EPA's description of
it as such is erroneous. The commenter goes on to compare and contrast
specific differences between the method developed for Houston and the
1999 guidance.
Response: EPA continues to believe, in the case of the HG area, the
method developed is an improvement over the November 1999 guidance.
This guidance was developed for estimating the additional reduction
needed to support the one-hour ozone NAAQS for those nonattainment
areas using a weight of evidence approach to

[[Page 57175]]

demonstrating attainment. This guidance describes two methods for
calculating the amount of the additional reductions needed, but does
not prohibit the use of an alternative method. Both methods assume that
the relationship between ozone and the NO_X and VOC
precursors can be estimated. Direct application of the two methods
discussed in EPA's November 1999 guidance using available data for the
Houston area, produced a mathematical impossibility. The results
indicated that all ozone precursor emissions would have to be reduced
to less than zero. Thus, the two methods described in the 1999 guidance
are not directly applicable to Houston. EPA and TNRCC worked together
to develop a revised method that is consistent with the concepts in the
1999 guidance for estimating the relationship, but applicable to the
Houston area's modeling results. The methods in the guidance use a
linear extrapolation of model results to determine expected ozone
benefits from additional precursor reductions. The method for the
Houston area is also an extrapolation of model results. Instead of a
linear extrapolation, however, a quadratic extrapolation was developed
based on the results of three of the modeling runs. A quadratic
extrapolation is necessary because of the non-linearity of the ozone
response to NO_X reductions in the Houston area. Therefore,
the method developed for the HG area is a refinement the two methods in
the 1999 guidance, since these two methods are also based on modeling.
The factors used in the method for the Houston area are based on model
results for the majority of the control measures and, consequently, are
scientifically sound for the Houston area. We believe this approach is
consistent with the intent and criteria of the 1999 guidance and, in
the case of the Houston area, gives a better approximation of the
amount of emission reductions that will be necessary to achieve the
standard. Therefore, this method fulfills the purposes of the EPA
guidance, and it is as rigorous, if not more rigorous, than the two
methods discussed in the 1999 guidance. Furthermore, it cannot be
accurate to characterize the methods in the 1999 guidance as better
when, in fact, they produce a mathematical impossibility for the HG
area.
3. Comments on Control Strategies
Comment: One commenter stated that the plan should provide evidence
that Texas Senate Bill 5 (SB-5) provisions can be implemented and will
lead to at least 6.7 tons/day of NO_X emission reductions.
Another commenter stated EPA should not give credit to the Texas
Emission Reduction Plan created by SB-5 without assurances of long-term
funding levels and details about long-term funding. They also cite
information that the funding for the program might be less than EPA
assumed because of legal challenges.
Response: Based on experience in California with the Carl Moyer
program, the Diesel Emission Reduction Program provided by the Texas
Legislature should be able to provide emissions reduction in the range
of $3000-5000/ton. This is documented in the report ``The Carl Moyer
Memorial Air Quality Standards Attainment Program (The Carl Moyer
Program) Guidelines-Approved Revision 2000, November 16, 2000
California Environmental Protection Agency Air Resources Board.'' The
clear intent of the legislation, as stated on the TNRCC website, is
``The highest priority for using the funds under the Emissions
Reduction Grants Program will be to replace NO_X emissions
reductions removed from the State Implementation Plans (SIPs) for the
HG area and Dallas/Fort Worth (DFW) nonattainment areas as a result of
S.B. 5. Using an average of $5,000 per ton of NO_X reduced,
the TNRCC has determined that it will require $6.7 million per year in
HGA to replace the construction shift and accelerated Tier II/III
rules. Another $7.5 million will be required to partially fill (20
tons) the 56 ton gap, making the HG area total $14.2 million.''
EPA's estimates are not as optimistic but we do believe the $24.7
million/yr projected on the TNRCC website should result in at least 25
tons/year of emission reductions, an amount sufficient to offset the
construction shift and accelerated Tier II/III and contribute to
reducing the shortfall. We will work with Texas to refine the estimates
of emission reductions. It is clear that if more money is needed for
the HG area as the program is implemented to make additional reductions
in the shortfall, the TNRCC has the discretion to channel more money to
the Houston area.
With regard to legal challenges to the program's funding
mechanisms, EPA will not anticipate a court's findings. If a court
finds the funding mechanism illegal, Texas will have to revise the SIP
at that time to address the loss in emission reductions or find
alternative funding sources. In the absence of timely State action to
address any adverse court ruling, EPA could take action to ensure
attainment is not jeopardized.
Comment: Commenters questioned the emissions benefit of the low
emission diesel rule.
Response: The EPA has just completed a study of the benefits of low
emission diesel fuels, such as the Texas Clean Diesel fuel. EPA
determined the Texas fuel will result in NO_X reductions.
However, it appears that the NO_X reductions based on the
just-completed study will be slightly less than those projected by
Texas. EPA believes, because the emissions impact is expected to be
small and because Texas has committed to address any change to the
amount of needed emission reductions at the mid-course review, the
recent study findings do not change the approvability of the attainment
demonstration. We will work with Texas to incorporate the findings of
the study into future SIP revisions.
Comment: One commenter supported the fact that EPA did not take any
action on morning construction ban.
Response: EPA determined not to take action on the construction ban
since the legislature had removed the TNRCC's authority to implement
this measure.
Comment: EPA must discount the emission reduction credit from the
Airport Ground Support Equipment agreed orders because these orders do
not assign specific budgets to individual airlines and therefore do not
insure the achievement of any particular ton/day emissions.
Response: The agreed orders require percentage reductions from a
1996 baseline which achieve the same purpose as an emissions
limitation. The reductions specified in each order are enforceable
against the owner/operator of the equipment, thus providing a
comfortable degree of certainty that the reductions will take place.
Comment: The EPA should discount the emission reductions from I/M
based on the recently released National Research Council (NRC) Report.
Response: The NRC recommendation provides that the models
projecting emissions from I/M programs should be improved to reflect
actual reductions more accurately. EPA agrees that emission performance
of vehicles has improved since the data that form the basis of existing
models were generated. Most of the data for MOBILE5 was based on
evaluation of early 1980's vehicles.
EPA's soon-to-be-released MOBILE6 model has been substantially
updated to better reflect actual emissions and actual I/M benefits. The
model has also been made more flexible to better incorporate local data
on compliance, technician training, and the inclusion/exclusion of
vehicles of certain ages. As technologies and characteristics of the

[[Page 57176]]

fleet change, data collection, analysis, and model improvement will
likely continue to be warranted. Texas has committed to revise the
Mobile Vehicle Emissions Budget using MOBILE6 no later than 2 years
after its official release. If a transportation conformity analysis is
to be performed between 12 months and 24 months after the MOBILE6
official release, transportation conformity will not be determined
until Texas submits an MVEB which is developed using MOBILE6 and which
we find adequate. Further, it is our understanding that TNRCC intends
to use Mobile 6 in the attainment demonstration modeling planned for
submission in December 2002.
Comment: The Act requires the SIP to include a program to provide
for enforcement of the adopted measures. Most plans address this
requirement, however, none of the plans clearly set out programs to
provide for enforcement. Another commenter said the EPA should take
steps to insure adequate enforcement of permit standards. Other
commenters said the plan includes unenforceable items such as the
restriction on commercial lawn mowing.
Response: State enforcement program elements are contained in SIP
revisions previously approved by EPA under obligations set out in
section 110 of the Act. Once approved by the EPA, there is no need for
states to readopt and resubmit their enforcement programs with each and
every SIP revision generally required by other sections of the Act.
EPA will monitor the effectiveness of the new programs, such as the
commercial lawn mowing restriction, and work with Texas to revise the
programs if necessary.
Comment: The State submittal should include creditable, adequate
rules to achieve attainment that should also provide for a margin for
error.
Response: EPA generally agrees with the comment. EPA believes that
the Margin of Error for the HG area plan, while small, is appropriate
in light of the significant level of reductions in the plan and the
commitment to perform the mid-course review and to adopt additional
measures as appropriate.
Comment: One commenter stated that there is over crediting of
national rules for architectural coatings, auto-refinishing coatings
and consumer products. They state the credit claimed is based on EPA
estimates of emission reductions from proposed versions of these rules,
but the final versions of the rules are weaker than the proposed rules.
Therefore, the credit claimed for these national rules should be
recalculated to reflect only the actual emission reductions that can be
expected under the final EPA rules.
Response: Architectural Coatings: EPA's March 22, 1995 memorandum
\8\ indicated EPA's view that it was acceptable for states to claim a
20% reduction in VOC emissions from the AIM coatings category in ROP
and attainment demonstration plans based on the anticipated
promulgation of a national AIM coatings rule. In developing the
attainment SIP for the Houston area, Texas relied on this memorandum to
estimate emission reductions from the anticipated national AIM rule.
EPA promulgated the final AIM rule in September 1998, codified at 40
CFR part 59, subpart D. In the preamble to EPA's final AIM coatings
regulation, EPA estimated that the regulation will result in 20%
reduction of nationwide VOC emissions from AIM coatings categories (63
FR 48855). The estimated VOC reductions from the final AIM rule
resulted in the same reductions as those estimated in the March 1995
EPA policy memorandum. In accordance with EPA's final regulation, Texas
has assumed a 20% reduction from AIM coatings source categories in its
attainment modeling. AIM coatings manufacturers were required to be in
compliance with the final regulation within one year of promulgation,
except for certain pesticide formulations which were given an
additional year to comply. Thus all manufacturers were required to
comply, at the latest, by September 2000. EPA believes that all
emission reductions from the AIM coatings national regulation will
occur by 2002 and therefore are creditable in the attainment plan for
the Houston area.
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\8\ ``Credit for the 15 Percent Rate-of-Progress Plans for
Reductions from the Architectural and Industrial Maintenance (AIM)
Coating Rules,'' March 22, 1995, from John S. Seitz, Director,
Office of Air Quality Planning and Standards to Air Division
Directors, Regions I-X.
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Autobody Refinish Coatings Rule: According to EPA's guidance \9\
and proposed national rule, many States have claimed a 37% reduction
from this source category based on a proposed rule. However, EPA's
final rule, ``National Volatile Organic Compound Emission Standards for
Automobile Refinish Coatings,'' published on September 11, 1998 (63 FR
48806), did not regulate lacquer topcoats and will result in a smaller
emission reduction of around 33% overall nationwide. The 37% emission
reduction from EPA's proposed rule was an estimate of the total
nationwide emission reduction. Since this number was an overall
average, it was not applicable to any specific area. For example, in
California the reduction from the national rule is zero because its
rules are more stringent than the national rule.
---------------------------------------------------------------------------

\9\ ``Credit for the 15 Percent Rate-of-Progress Plans for
Reductions from the Architectural and Industrial Maintenance (AIM)
Coating Rule and the Autobody Refinishing Rule,'' November 27, 1994,
from John S. Seitz, Director, OAQPS, to Air Division Directors,
Regions I-X.
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Texas did not rely on the above guidance. Instead, as part of the
development of their 15% Rate of Progress plan, Texas used data for
auto-refinishing coating use specific for Texas to estimate the
emission reductions from existing state rules. To avoid double
counting, for the purposes of the attainment demonstration, they did
not assume any additional emission reductions due to the national rule.
Therefore, the Houston area's attainment demonstration SIP relied on
state rules, not the national rule for its emission reductions. On
EPA's approval of the 15% ROP plan, EPA approves the credit Texas is
now relying on for attainment.
Consumer Products Rule: According to EPA's guidance \10\ and
proposed national rule, States have generally claimed a 20% reduction
from this source category. The final rule, ``National Volatile Organic
Compound Emission Standards for Consumer Products,'' (63 FR 48819),
published on September 11, 1998, will result in a 20% reduction.
Therefore the reductions obtained by States from the final national
rule are consistent with credit which was claimed.
---------------------------------------------------------------------------

\10\ ``Regulatory Schedule for Consumer and Commercial Products
under Section 183(e) of the Clean Air Act,'' June 22, 1995, from
John S. Seitz, Director, OAQPS, to Air Division Directors, Regions
I-X.
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Comment: One commenter included by reference their comments on the
TNRCC proposed rules. They include several comments opposing the
Construction Hour shift, Accelerated Tier II/III, NO_X
Reduction Systems (a requirement to retrofit off-road equipment), and
low sulfur gasoline.
Response: As all of these measures have been dropped from the
State's plan and were not submitted to EPA. Thus, no response is
necessary.
4. Comments on Enforceable Commitments
Comment: Several commenters claim that EPA should not approve the
attainment demonstration for the HG area because the plan contains, in
part, commitments to adopt measures that are necessary to reach
attainment. The commenters contend that EPA does not have authority to
accept enforceable commitments to adopt measures in the

[[Page 57177]]

future in lieu of adopted control measures.
The commenters contend that the 56 tpd gap must be closed now. The
commenters are concerned that Texas has proposed a process that will
take three more years--until 2004--to develop and adopt the final
control measures needed for attainment. Deferred adoption and submittal
are not consistent with the statutory mandates and are not consistent
with the Act's demand that all SIPs contain enforceable measures. EPA
does not have authority to approve a SIP if part of the SIP is not
adequate to meet all tests for approval. Because the submittal consists
in part of commitments, Texas has not adopted rules implementing final
control strategies, and the plan includes insufficient reduction
strategies to meet the emission reduction goals established by the
TNRCC. Thus, Texas has failed to adopt a SIP with sufficient adopted
and enforceable measures to achieve attainment. For these reasons, the
submittal also does not meet the NRDC's consent decree definition of a
``full attainment demonstration SIP,'' which obligates EPA to propose a
federal implementation plan if it does not approve the HG area SIP. For
these reasons, EPA should reject the HG area SIP and impose sanctions
on the area and publish a proposed FIP no later than October 15, 2001.
Response: EPA disagrees with the comments, and believes--consistent
with past practice--that the Act allows approval of enforceable
commitments that are limited in scope where circumstances exist that
warrant the use of such commitments in place of adopted measures.\11\
Once EPA determines that circumstances warrant consideration of an
enforceable commitment, EPA believes that three factors should be
considered in determining whether to approve the enforceable
commitment: (1) Whether the commitment addresses a limited portion of
the statutorily-required program; (2) whether the state is capable of
fulfilling its commitment; and (3) whether the commitment is for a
reasonable and appropriate period of time.
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\11\ These commitments are enforcd by the EPA and citizens
under, repesctively, sections 113 adn 301 of the Act. In the past,
EPA has approved enforceable commitments and courts have enforced
these actions against states that failed to comply with those
commitments. See, e.g., American Lung Association of New Jersey v.
Kean, 670 F. Supp. 1285 (D.N.J 1987), affirmed, 871 F.2d 319 (3rd
Cir. 1989); NRDC v. N.Y. State Dept. of Environmental Conservation,
668 F. Supp. 848 (S.D.N.Y. 1987); Citizens for a Better Environment
v. Deukmejian, 731 F. Supp. 1448, reconsideration granted in part,
746 F. Supp. 976 (N.D. Cal. 1990); Coalition for Clean Air, et al.
v. South Coast Air Quality Management District, CARB and EPA, No. CV
97-6916 HLH, (C.D. Cal. August 27, 1999). Further, if a state fails
to meet its commitments, EPA could make a finding of failure to
implement the SIP under Section 179(a), which would start an 18-
month period for the State to begin implementation before mandatory
sactions are imposed.
---------------------------------------------------------------------------

As an initial matter, EPA believes that present circumstances for
the New York City, Philadelphia, Baltimore and Houston nonattainment
areas warrant the consideration of enforceable commitments. The
Northeast states that make up the New York, Baltimore, and Philadelphia
nonattainment areas submitted SIPs that they reasonably believed
demonstrated attainment with fully adopted measures. After EPA's
initial review of the plans, EPA recommended to these areas that
additional controls would be necessary to ensure attainment. Because
these areas had already submitted plans with many fully adopted rules
and the adoption of additional rules would take some time, EPA believed
it was appropriate to allow these areas to supplement their plans with
enforceable commitments to adopt and submit control measures to achieve
the additional necessary reductions. For the HG area, the State has
submitted supporting information that EPA has confirmed indicating that
Texas has adopted for the HG area NO_X controls that are as
tight or tighter than any other area including the one extreme area--
South Coast. Thus, because the State has adopted many strict controls
that were included in the submitted plan and needs additional time to
consider technologies that are still in the developmental stages, EPA
determined that it is appropriate to consider an enforceable commitment
for the remaining necessary reductions. For the HG area, EPA has
determined that the submission of enforceable commitments in place of
adopted control measures for this limited set of reductions will not
interfere with the area's ability to meet its rate-of-progress
obligations.
EPA's approach here of considering enforceable commitments that are
limited in scope is not new. EPA has historically recognized that under
certain circumstances, issuing full approval may be appropriate for a
submission that consists, in part, of an enforceable commitment. See
e.g., 62 FR 1150, 1187 (Jan. 8, 1997) (ozone attainment demonstration
for the South Coast Air Basin); 65 FR 18903 (Apr. 10, 2000) (revisions
to attainment demonstration for the South Coast Air Basin); 63 FR 41326
(Aug. 3, 1998) (federal implementation plan for PM-10 for Phoenix); 48
FR 51472 (State Implementation Plan for New Jersey). Nothing in the Act
speaks directly to the approvability of enforceable commitments.\12\
However, EPA believes that its interpretation is consistent with
provisions of the Act. For example, section 110(a)(2)(A) provides that
each SIP ``shall 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 met
the applicable requirement of the Act.'' Section 172(c)(6) of the Act
requires, as a rule generally applicable to nonattainment SIPs, that
the SIP ``include enforceable emission limitations and such other
control measures, means or techniques * * * as may be necessary or
appropriate to provide for attainment * * * by the applicable
attainment date * * *'' (Emphasis added.) The emphasized terms mean
that enforceable emission limitations and other control measures do not
necessarily need to generate reductions in the full amount needed to
attain. Rather, the emissions limitations and other control measures
may be supplemented with other SIP rules--for example, the enforceable
commitments EPA is approving today--as long as the entire package of
measures and rules provides for attainment. EPA's interpretation that
the Act allows for a approval of limited enforceable commitments has
been upheld by the courts of appeals in some circuits. See City of
Seabrook v. EPA, 659 F.2d 1349 (5th Cir. 1981); Connecticut Fund for
the Environment v. EPA, 672 F.2d 998 (2d Cir.), cert. denied 459 U.S.
1035 (1982); Friends of the Earth v. EPA, 499 F.2d 1118 (2d Cir. 1974);
Kamp v. Hernandez, 752 F.2d 1444 (9th Cir. 1985).
---------------------------------------------------------------------------

\12\ Section 110(k)(4) provides for ``conditional approval'' of
commitments that need not be enforceable. Under that section, a
State may commit to ``adopt specific enforceable measures'' within
one-year of the conditional approval. Rather than enforcing such
commitments against the State, the Act provides that the conditional
approval will convert to a disapproval if ``the State fails to
comply with such commitment.''
---------------------------------------------------------------------------

As provided above, after concluding that the circumstances warrant
consideration of an enforceable commitment--as they do for the HG
area--EPA would consider three factors in determining whether to
approve the submitted commitments. First, EPA believes that the
commitments must be limited in scope. In 1994, in considering EPA's
authority under section 110(k)(4) to conditionally approve
unenforceable commitments, the Court of Appeals for the District of
Columbia Circuit struck down an EPA policy that would allow

[[Page 57178]]

States to submit (under limited circumstances) commitments for entire
programs. Natural Resources Defense Council v. EPA, 22 F.3d 1125 (D.C.
Cir. 1994). While EPA does not believe that case is directly applicable
here, EPA agrees with the Court that other provisions in the Act
contemplate that a SIP submission will consist of more than a mere
commitment. See NRDC, 22. F.3d at 1134.
In the present circumstances, the commitments address only a small
portion of the plan. For the HG area, the commitment addresses only 6%
of the emission reductions necessary to attain the standard. Already
adopted measures include controls to reduce NO_X emissions by
approximately 90% from industrial sources, a more stringent and
expanded I/M program, a Clean Diesel Program, a well-funded incentive
program to encourage the early introduction of cleaner diesel
equipment, controls on airport ground support equipment, and several
voluntary measures to reduce emissions from mobile sources.
As to the second factor, whether the State is capable of fulfilling
the commitment, EPA considered the current or potential availability of
measures capable of achieving the additional level of reductions
represented by the commitment and whether the State has or is capable
of getting the requisite authority to adopt measures to achieve those
reductions.
For HG area, the SIP submittal already includes substantial
reductions, covering every significant NO_X source category.
The SIP for the HG area already includes NO_X control
requirements that, overall, are more expensive and technologically
advanced, and apply to smaller emitters, than those in any other SIP in
the nation other than the South Coast--the one area classified as
extreme for the 1-hour ozone standard. Thus, determining measures that
will generate the necessary additional reductions is significantly more
complex than for the northeastern States. However, the State has
provided EPA with sufficient information to assure EPA that it will be
capable of adopting controls to achieve the necessary level of emission
reductions. First, the State has identified advanced technologies and
innovative ideas that, in EPA's opinion, are or will be shortly
available and thus could be adopted and implemented in sufficient time
for the HG area to attain by 2007. Furthermore, the State has
identified a range of emission reductions that potentially could be
achieved by each of these advanced technologies and innovative
strategies. While at this time the State--in conjunction with EPA--is
still working to assess the appropriate level of reductions that may be
achieved by these technologies and strategies, EPA believes that the
totality of the current information is sufficient to assure EPA that
Texas can meet its commitment to adopt measures that will achieve the
level of reductions necessary to meet the HG area's shortfall.
The third factor, EPA has considered in determining to approve
limited commitments for the HG area attainment demonstration is whether
the commitment is for a reasonable and appropriate period. EPA
recognizes that both the Act and EPA have historically emphasized the
need for submission of adopted control measures in order to ensure
expeditious implementation and achievement of required emissions
reductions. Thus, to the extent that other factors--such as the need to
consider innovative control strategies--support the consideration of an
enforceable commitment in place of adopted control measures, the
commitment should provide for the adoption of the necessary control
measures on an expeditious, yet practicable, schedule.
Texas is faced with exploring cutting-edge technology, as it has
already required extremely stringent controls. Thus, in considering the
appropriate amount of time for Texas to meet its commitment, EPA
considered that Texas needs time to develop and assess the capabilities
of these technologies in addition to the time it needs to adopt the
measures that will achieve the needed level of emission reductions.
Because some of the measures that Texas is considering are further
along in the development process, Texas has committed to adopt measures
to fill a portion of the shortfall in the near term and to adopt the
remaining measures by an intermediate-term date. Thus, Texas has
committed to adopt controls to achieve 25% of the needed emission
reductions by December 2002 and to adopt controls to achieve the
remaining level of reduction by May 1, 2004. EPA believes that this
schedule is expeditious in light of the types of cutting-edge controls
that Texas needs to evaluate, develop and then adopt in order to
achieve the level of reductions needed in the HG area. In addition, EPA
believes that these adoption dates will not impede Houston's ability to
attain the 1-hour ozone standard by November 15, 2007 nor will it
impede Houston's ability to meet the ROP requirement because the HG
area can meet the ROP requirement with already adopted measures.
The enforceable commitments submitted for the HG nonattainment
area, in conjunction with the other SIP measures and other sources of
emissions reductions, constitute the required demonstration of
attainment and the commitments will not interfere with the area's
ability to make reasonable progress under section 182(c)(2)(B) and (d).
EPA believes that the delay in submittal of the final rules is
permissible under section 110(k)(3) because the State has obligated
itself to submit the rules by specified short-term and intermediate-
term dates, and that obligation is enforceable by EPA and the public.
Moreover, as discussed in the proposal and TSD, the SIP submittal
approved today contains major substantive components submitted as
adopted regulations and enforceable orders.
EPA does not agree with the assertion that the HG area SIP does not
meet the NRDC consent decree definition of a ``full attainment
demonstration.'' The consent decree defines a ``full attainment
demonstration'' as a demonstration according to CAA section 182(c)(2).
As a whole, the attainment demonstration--consisting of photochemical
grid modeling, adopted control measures, an enforceable commitment with
respect to a limited portion of the reductions necessary to attain, and
other analyses and documentation--is approvable since it ``provides for
attainment of the ozone (NAAQS) by the applicable attainment date.''
See section 182(c)(2)(A).
Comment: The SIP includes explicit enforceable commitments to
consider relaxing regulations on industrial point sources. EPA must
reject any efforts to relax effective control measures on the books
before the TNRCC eliminates the identified shortfall in emission
reductions. Proposed changes to the plan would commit the TNRCC to
consider steps that will unlawfully increase the gap between predicted
emission reductions resulting from regulatory measures and the emission
reduction goals established by the TNRCC. Further, it is unlawful for
the SIP to contain a promise to relax NO_X point sources in
exchange for implementation of measures to control upset emissions.
Response: The TNRCC has included in Chapter 7 of the SIP its
commitment to developing an enforceable plan to reduce releases of
reactive hydrocarbon emissions and emissions of chlorine. Recent
findings from the Texas 2000 Air Quality Study indicate that highly
reactive hydrocarbons and/or chlorine emissions may be primary causes
of the rapid build-up of ozone in the HG area.

[[Page 57179]]

TNRCC goes on to say that to the extent that the science confirms the
benefit from this program then it is the intent of the commission to
implement such a program through a SIP revision which would also
decrease NO_X reductions required from industrial sources
down to 80% control. At this time, EPA is not acting on whether this
potential, future SIP revision would be approvable. At this time, we
are considering only the effective State rules before us that include
90% control on industrial source NO_X emissions. The State's
commitment to consider alternative control strategies in the future has
no bearing on this approval. The Supreme Court has consistently held
that under the Act, initial and primary responsibility for deciding
what emissions reductions will be required from which sources is left
to the discretion of the States. Whitman v. Am. Trucking Ass'ns, 531
U.S. 457 (2001); Train v. NRDC, 421 U.S. 60 (1975). This discretion
includes the continuing authority to revise choices about the mix of
emission limitations. Train at 79. Therefore, EPA believes that it is
appropriate and authorized under the Act for a State to continue to
update its growth projections, inventories, modeling analyses, control
strategies, etc., and submit these updates as a SIP revision based on
newly available science and technology.
However, section 110(l) of the Act governs EPA's review of a SIP
revision from a state that wishes to make changes to its approved SIP.
This section provides that EPA may not approve a SIP revision if it
will interfere with any applicable requirement concerning attainment
and reasonable further progress or any other applicable requirement of
the Act.\13\ Therefore, if we receive an attainment demonstration SIP
revision from Texas that contains relaxed control measures or the
replacement of existing control measures, we would consider the revised
plan's prospects for meeting the current attainment requirements and
other applicable requirements of the Act. See, the Act section
110(k)(3), Union Electric v. EPA, 427 U.S. 246 (1976) and Train, 421
U.S. at 79.
---------------------------------------------------------------------------

\13\ The Supreme Court under the 1970 CAA, observed that EPA's
judgment in determining the approval of a SIP revision is to
``measure the existing level of pollution, compare it with the
national standards, and determine the effect on this comparison of
specified emission modifications.'' Train at 93.
---------------------------------------------------------------------------

In summary, the State may choose to submit a SIP revision in 2002
or 2003 as it has suggested it may do. If we receive a SIP revision
that meets our completeness criteria, we will review it against the
statutory requirements of section 110(l). Further, the Act requires us
to publish a notice and to provide for public comment on our proposed
decision. EPA believes that it is in the context of that future
rulemaking, not EPA's current approval, that the commenter's concern
regarding the appropriateness of any replacement measures adopted by
the State should be considered.
Comment: The mid-course review process outlined by TNRCC is not a
permissible substitute for a currently complete attainment
demonstration or adopted enforceable control measures. The mid-course
review will delay final approval of the SIP until 2004, 10 years after
the SIP was required under the Act.
Response: The mid-course review is not intended as a replacement
for a complete attainment demonstration or as a replacement for adopted
control measures. As provided elsewhere in the responses to comments,
EPA believes the State's commitment to adopt additional measures is
appropriate. It is intended to reflect the reality that the modeling
techniques and inputs are uncertain. Thus, the progress of implementing
the plan should be evaluated so that adjustments can be made to ensure
the plan is successful. EPA is fully approving the attainment
demonstration based on the information currently available. The mid-
course review allows the State and EPA an opportunity to consider
additional information closer to the attainment date to assess whether
adjustments are necessary.
In the case of Texas, the State has extensive plans to fully
evaluate the inputs to the model and the modeling itself using the most
up to date information possible. The State will also be evaluating
several new control measures for inclusion in the SIP. We are fully
supportive of this continued evaluation of the science supporting the
plan to reach attainment.
Comment: TNRCC has failed to meet its commitment to provide a plan
by July 8, 2001. The TNRCC has reneged on previous commitments to model
attainment. These demonstrate reasons for our objection to EPA's
reliance on commitments.
Response: We do not agree that TNRCC has reneged on previous
commitments to model attainment. As discussed in the response to
comments on modeling, using weight of evidence in conjunction with the
model is an appropriate method of demonstrating attainment. Further,
Texas has made every effort to adopt all of the necessary measures to
demonstrate attainment. Therefore, as discussed previously, EPA
believes that it is acceptable to allow additional time for the
development of new programs or measures for a small percentage of the
needed reductions.
Comment: Texas provided a comment letter on EPA's December 1999
proposal. In this letter, Texas explained their plans to provide the
following elements and enforceable commitments by April 2000: (1) A
list of measures that could be used to achieve attainment (2) a
commitment to provide a new mobile source emissions budget using
MOBILE6 by May 2004, (3) a reenforcement of their previous commitment
to adopt the majority of necessary rules for attainment by December 31,
2000, and to adopt the remainder if necessary by July 31, 2001, and (4)
a commitment to perform a mid-course review.
Response: TNRCC adopted these elements in April 2000. We are now
approving the commitments that are still relevant. (See the final
action section).
Comment: One commenter suggested several specific language changes
to the enforceable commitments in the Texas SIP.
Response: EPA and TNRCC met and agreed that some but not all of the
language changes should be made. The section on changes from the
proposal explain these changes. Other specific language changes
proposed by the commenters are not necessary for approvable enforceable
commitments.
5. Comments on Motor Vehicle Emissions Budgets
a. Comments on the July 12, 2001 Proposal
Comment: The commenters raised several questions concerning the
Motor Vehicle Emissions Budgets (the budgets) established in the
Houston attainment demonstration SIP. The commenters stated that the
budgets submitted in the SIP should not be called adequate or be
approved by the EPA because the attainment demonstration SIP does not
provide for attainment. One commenter specifically pointed to the need
for adopted and enforceable control measures.
Response: The rate-of-progress (ROP) budgets for the year of 2007
are 79.5 tpd and 156.7 tpd for VOC and NO_X, respectively.
The commenters support these budgets. In addition, these budgets are
identified as the budgets for the 2007 attainment demonstration SIP
which are being approved by the EPA only until revised budgets pursuant
to the State's commitments relating to MOBILE6 and shortfall measures
are

[[Page 57180]]

submitted and we have found them adequate for transportation conformity
purposes. Approval of the attainment budgets is based on the current
control measures specified in the SIP and the enforceable commitments
made for additional controls which will be implemented in the interim
period. Because all measures which have not yet been adopted are
included in written commitments in the SIP, EPA believes that it can
find the budgets adequate. The EPA believes that consistency of the
budgets related to the emissions inventory, and SIP control strategy
are demonstrated and meet the requirements of 40 CFR 93.118(e).
Therefore, the budgets for the attainment demonstration SIP are
adequate for transportation conformity purposes. Also, it should be
noted that the conformity rules allow emission reduction credit to be
taken for purposes of conformity determinations for any measures that
have been either adopted by the enforcing jurisdiction, included in the
applicable implementation plan, contained in a written commitment in
the submitted implementation plan, or promulgated by EPA as a federal
measure. See 40 CFR 93.122(a)(3).
As described in the November 3, 1999 memorandum entitled ``Guidance
on Motor Vehicle Emissions Budgets in One-Hour Ozone Attainment
Demonstrations,'' from Marylin Zaw-Mon, Office of Mobile Sources, to
Air Division Directors, Regions I-VI, there are circumstances in which
the EPA could find a SIP's motor vehicle emissions budgets adequate
even though additional emission reductions are necessary in order to
demonstrate attainment. Specifically, the EPA's position is that the
motor vehicle emissions budgets could be adequate for conformity
purposes if the State commits to adopt, for the area, measures that
will achieve the necessary additional reductions, and the State
identifies a menu of possible measures that could achieve the
reductions without requiring additional limits on highway construction.
The HG area's SIP contains such commitments and such a menu.
We believe that the budgets can be found adequate and approvable
because the budgets will not interfere with the area's ability to adopt
additional measures to attain the ozone standard and they are
consistent with the attainment demonstration SIP. While the area is
adopting its additional measures, the SIP's budgets will cap motor
vehicle emissions and thereby ensure that the amount of additional
reductions necessary to demonstrate attainment will not increase. The
budgets are consistent with and clearly related to the emissions
inventory and the control measures and consistent with attainment. EPA
disagrees that the SIP does not provide for attainment. For further
explanation of how this attainment demonstration SIP as an overall plan
provides for attainment please see other responses directly relating to
the sufficiency of the overall attainment plan, control strategy,
enforceable commitments, etc. contained in this final action.
Comment: The commenters asserted that further NO_X
reductions needed for attainment will require additional on-road mobile
source controls and these controls will result in a lower motor vehicle
emissions budget. The commenters felt that the budgets established in
the SIP are too high and the NO_X budgets should be reduced
by 30 or more tpd.
Response: Agency policy for the areas needing additional emission
reductions has provided that, in certain cases, EPA may determine the
budget adequate even when the SIP includes commitments to additional
measures. In a November 3, 1999, Memorandum entitled ``Guidance on
Motor Vehicle Emissions Budgets in One-Hour Ozone Attainment
Demonstrations,'' EPA issued guidance regarding such commitments in the
ozone attainment demonstrations for the HG area as well as other areas.
We indicated that budgets could be based on potential control measures
identified in the SIP that, when implemented, would be expected to
achieve the emission reductions necessary for attainment of the
standard and a commitment to adopt measures to achieve the reductions.
These measures may not involve additional limits on highway
construction beyond the restrictions already imposed under the
submitted motor vehicle emissions budget. As long as the additional
measures do not involve additional limits on highway construction,
allowing new transportation investments consistent with the submitted
budgets will not prevent the area from achieving the additional
reductions that it needs for attainment. This allows the EPA to
consider the budgets adequate for transportation conformity purposes.
The HG area SIP contains such commitments and measures. The SIP
demonstrates that the budgets will not interfere with the HG area's
ability to adopt additional measures to attain.
The budgets established in the SIP are consistent with the process
in 40 CFR 93.118(e), and the EPA does not consider them too high within
the context of the ozone attainment demonstration SIP as described
above and further documented in the SIP and EPA's TSD. The budgets are
consistent with and clearly related to the emissions inventory and the
control measures and consistent with attainment. Our approval of the
budgets is limited until revised budgets are submitted and we have
found them adequate for transportation conformity purposes. Texas has
committed to revise the budgets relating to MOBILE6 and the shortfall
measures. While the list of potential measures does include measures
that pertain to motor vehicles, none of the measures involves
additional limits on highway construction; therefore, if lower budgets
do result, the transportation investments will still be consistent with
the budgets and will not prevent the HG area from achieving attainment.
Comment: The motor vehicle emissions budgets are inadequate because
they do not provide for all reasonably available control measures to
attain the standard as expeditiously as practicable.
Response: The motor vehicle emissions budgets are adequate. The SIP
includes all necessary RACM and provides for expeditious attainment as
explained further in the RACM section of this action.
b. Comments on July 28, 2001 Supplemental Notice
Comment: One commenter generally supports a policy of requiring
motor vehicle emissions budgets to be recalculated when revised MOBILE
models are released.
Response: The Phase II attainment demonstrations that rely on Tier
2 emission reduction credit contain commitments to revise the motor
vehicle emissions budgets after MOBILE6 is released.
Comment: The revised budgets calculated using MOBILE6 will likely
be submitted after the MOBILE5 budgets have already been approved.
EPA's policy is that submitted SIPs may not replace approved SIPs.
Response: This is the reason that EPA proposed in its July 28, 2000
Supplemental Notice of Proposed Rulemaking (65 FR 46383) that the
approval of the MOBILE5 budgets for conformity purposes would last only
until MOBILE6 budgets had been submitted and found adequate. In this
way, the MOBILE6 budgets can apply for conformity purposes as soon as
they are found adequate.
Comment: If a State submits additional control measures that affect
the motor vehicle emissions budgets but does not submit revised motor
vehicle

[[Page 57181]]

emissions budgets, EPA should not approve the attainment demonstration.
Response: EPA agrees. The motor vehicle emissions budgets in the HG
area attainment demonstration reflect the motor vehicle control
measures in the attainment demonstration. In addition, Texas would be
required to submit a new budget if any adopted measures would change
the budget, and Texas has committed to submit a new budget if they
adopt additional control measures that reduce on-road vehicle
emissions.
Comment: EPA should make it clear that the motor vehicle emissions
budgets to be used for conformity purposes will be determined from the
total motor vehicle emissions reductions required in the SIP, even if
the SIP does not explicitly quantify a revised motor vehicle emissions
budget.
Response: EPA will not approve SIPs without motor vehicle emissions
budgets that are explicitly quantified for conformity purposes. The HG
attainment demonstration contains explicitly quantified motor vehicle
emissions budgets which EPA has found adequate and approvable.
Comment: If a state fails to follow through on its commitment to
submit the revised motor vehicle emissions budgets using MOBILE6, EPA
could make a finding of failure to submit a portion of a SIP, which
would trigger a sanctions clock under section 179.
Response: If a state fails to meet its commitment, EPA could make a
finding of failure to implement the SIP, which would start a sanctions
clock under section 179 of the Act.
Comment: If the budgets recalculated using MOBILE6 are larger than
the MOBILE5 budgets, then attainment should be demonstrated again.
Response: As EPA proposed in its December 16, 1999 notices, we will
work with States on a case-by-case basis if the new emissions estimates
raise issues about the sufficiency of the attainment demonstration.
Comment: If the MOBILE6 budgets are smaller than the MOBILE5
budgets, the difference between the budgets should not be available for
reallocation to other sources unless air quality data show that the
area is attaining, and a revised attainment demonstration is submitted
that demonstrates that the increased emissions are consistent with
attainment and maintenance. Similarly, the MOBILE5 budgets should not
be retained (while MOBILE6 is being used for conformity demonstrations)
unless the above conditions are met.
Response: EPA agrees that if recalculation using MOBILE6 shows
lower motor vehicle emissions than MOBILE5, then these motor vehicle
emission reductions cannot be reallocated to other sources or assigned
to the motor vehicle emissions budget unless the area reassesses the
analysis in its attainment demonstration and shows that it will still
attain. In other words, the area must assess how its original
attainment demonstration is impacted by using MOBILE6 vs. MOBILE5
before it reallocates any apparent motor vehicle emission reductions
resulting from the use of MOBILE6. In addition, Texas will be
submitting new budgets based on MOBILE6 so the MOBILE5 budgets will not
be retained in the SIP indefinitely.
Comment: We received a comment on whether the grace period before
MOBILE6 is required in conformity determinations will be consistent
with the schedules for revising SIP motor vehicle emissions budgets
(``budgets'') within 1 or 2 years of MOBILE6's release.
Response: This comment is not germane to this rulemaking, since the
MOBILE6 grace period for conformity determinations is not explicitly
tied to EPA's SIP policy and approvals. However, EPA understands that a
longer grace period would allow some areas to better transition to new
MOBILE6 budgets. EPA is considering the maximum 2-year grace period
allowed by the conformity rule, and EPA will address this in the future
when the final MOBILE6 emissions model and policy guidance is released.
Comment: One commenter asked EPA to clarify in the final rule
whether MOBILE6 will be required for conformity determinations once new
MOBILE6 budgets are submitted and found adequate.
Response: This comment is not germane to this rulemaking. However,
it is important to note that EPA intends to clarify its policy for
implementing MOBILE6 in conformity determinations when the final
MOBILE6 model is released. EPA believes that MOBILE6 should be used in
conformity determinations once new MOBILE6 budgets are found adequate.
Comment: One commenter did not prefer the additional option for a
second year before the state has to revise the conformity budgets with
MOBILE6, since new conformity determinations and new transportation
projects could be delayed in the second year.
Response: EPA proposed the additional option to provide further
flexibility in managing MOBILE6 budget revisions. The supplemental
proposal did not change the original option to revise budgets within
one year of MOBILE6's release. State and local governments can continue
to use the 1-year option, if desired, or submit a new commitment
consistent with the alternative 2-year option. EPA expects that state
and local agencies have consulted on which option is appropriate and
have considered the impact on future conformity determinations. Texas
has committed to revise its budgets within 2 years of MOBILE6's release
for the HG area. Texas has committed that if a transportation
conformity analysis is to be performed between 12 months and 24 months
after the MOBILE6 official release, transportation conformity will not
be determined until Texas submits an MVEB which is developed using
MOBILE6 and which we find adequate.
6. Comments on RACM
a. Comments on December 16, 1999 Proposal
Comment: Several commenters stated in response to the December 16,
1999 proposed approval/proposed disapprovals for the severe areas and
certain serious areas that there is no evidence in several states that
they have adopted reasonably available control measures (RACM) or that
the SIPs have provided for attainment as expeditiously as practicable.
Specifically, the lack of Transportation Control Measures (TCMs) was
cited in several comments, but potential stationary source controls
were also covered. One commenter stated that mobile source emission
budgets in the plans are by definition inadequate because the SIPs do
not demonstrate timely attainment or contain the emissions reductions
required for all RACM. That commenter claims that EPA may not find
adequate a motor vehicle emission budget (MVEB) that is derived from a
SIP that is inadequate for the purpose for which it is submitted. The
commenter alleges that none of the MVEBs submitted by the states that
EPA is considering for adequacy is consistent with either the level of
emissions achieved by implementation of all RACM nor are they derived
from SIPs that provide for attainment. Some commenters stated that for
measures that are not adopted into the SIP, the State must provide a
justification why they were determined to not be RACM.
Response: The EPA reviewed the November 1999 submission for the HG
area and determined that it did not include sufficient documentation
concerning available RACM measures. For all of the severe areas for
which EPA proposed approval in December 1999, EPA consequently issued
policy guidance memorandum to have these

[[Page 57182]]

States address the RACM requirement through an additional SIP submital.
(Memorandum of December 14, 2000, from John S. Seitz, Director, Office
of Air Quality Planning and Standards, re: ``Additional Submission on
RACM from States with Severe 1-hour Ozone Nonattainment Area SIPs.''
On May 30, 2001, TNRCC proposed a RACM analysis which we proposed
to approve on July 13, 2001 through parallel processing. The State
finalized its RACM analysis on September 26, 2001. The Governor
submitted this final RACM analysis in a letter dated October 4, 2001.
Based on this SIP supplement, EPA concluded that the SIP for the HG
area meets the requirement for adopting RACM.
Section 172(c)(1) of the Act requires SIPs to contain RACM and
provides for areas to attain as expeditiously as practicable. EPA has
previously provided guidance interpreting the requirements of
172(c)(1). See 57 FR 13498, 13560 (April 16, 1992). In that guidance,
EPA indicated its interpretation that potentially available measures
that would not advance the attainment date for an area would not be
considered RACM. EPA also indicated in that guidance that states should
consider all potentially available measures to determine whether they
were reasonably available for implementation in the area, and whether
they would advance the attainment date. Further, states should indicate
in their SIP submittals whether measures considered were reasonably
available or not, and if measures are reasonably available they must be
adopted as RACM. Finally, EPA indicated that states could reject
measures as not being RACM because they would not advance the
attainment date, would cause substantial widespread and long-term
adverse impacts, would be economically or technologically infeasible,
or would be unavailable based on local considerations, including costs.
The EPA also issued a recent memorandum re-confirming the principles in
the earlier guidance, entitled, ``Guidance on the Reasonably Available
Control Measures (RACM) Requirement and Attainment Demonstration
Submissions for Ozone Nonattainment Areas.'' John S. Seitz, Director,
Office of Air Quality Planning and Standards. November 30, 1999. Web
site: http://www.epa.gov/ttn/oarpg/t1pgm.html.
EPA evaluated the Texas RACM demonstration and performed an
additional analysis of TCMs as described in the TSD for the July 12,
2001 proposed approval. Specific comments on the RACM demonstration are
addressed in later responses to comments.
Although EPA does not believe that section 172(c)(1) requires
implementation of additional measures for the HG area, this conclusion
is not necessarily valid for other areas. Thus, a determination of RACM
is necessary on a case-by-case basis and will depend on the
circumstances for the individual area.\14\ In addition, if in the
future EPA moves forward to implement another ozone standard, this RACM
analysis would not control what is RACM for these or any other areas
for that other ozone standard.
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\14\ See, Ober v. EPA, 84 F.3d 304, 311 (9th cir. 1996) (citing
the General Preamble, 57 Fed.Reg. at 13560 (April 16, 1992) which
held that EPA did not abuse discretion when changing the
interpretation of the RACM provisions of the Act.
---------------------------------------------------------------------------

Also, EPA has long advocated that States consider the kinds of
control measures that the commenters have suggested, and EPA has indeed
provided guidance on those measures. See, e.g., http://www.epa.gov/
otaq/transp.htm. In order to demonstrate that they will attain the 1-
hour ozone NAAQS as expeditiously as practicable, some areas may need
to consider and adopt a number of measures-including the kind that
Texas itself evaluated in its RACM analysis--that even collectively do
not result in many emission reductions. Furthermore, EPA encourages
areas to implement technically available and economically feasible
measures to achieve emissions reductions in the short term-even if such
measures do not advance the attainment date-since such measures will
likely improve air quality. Also, over time, emission control measures
that may not be RACM now for an area may ultimately become feasible for
the same area due to advances in control technology or more cost-
effective implementation techniques. Thus, areas should continue to
assess the state of control technology as they make progress toward
attainment and consider new control technologies that may in fact
result in more expeditious improvement in air quality. The mid course
review process outlined by Texas in Chapter 7 of the SIP contains the
State's commitment to continue to evaluate new technologies as
potentially RACM, for inclusion later in the plan. The TNRCC adopted an
enforceable commitment to submit a revised SIP no later than May 1,
2004, addressing any new information including an ``ongoing assessment
of new technologies and innovative ideas to incorporate into the
plan.''
Because EPA is finding that the SIP meets the Clean Air Act's
requirement for RACM and that there are no additional reasonably
available control measures that can advance the attainment date, EPA
concludes that the attainment date being approved is as expeditiously
as practicable
EPA previously responded to comments concerning the adequacy of the
MVEBs submitted with the November 1999 SIP submission when EPA took
final action determining the budgets (associated with that 1999 plan)
adequate and does not address those issues again here. The responses
are found at http://www.epa.gov/oms/transp/conform/pastsips.htm. It
should be noted, since that time, EPA has found the MVEBs in the
November 1999 HG attainment demonstration SIP inadequate. (66 FR 35420,
July 5, 2001) We are now approving and finding adequate through
parallel processing the budgets finally submitted by Texas in a letter
dated October 4, 2001. The section of this notice on MVEBs explains why
the budgets are adequate and indicates that the budgets are consistent
with the conclusion that the SIP contains all necessary RACM for
expeditious attainment.
b. Comments on July 12, 2001 Proposal
Comment: EPA cannot invent rationales for the states: EPA concedes
that Texas failed to adequately justify rejection of RACMs identified
as measures to be considered in the future, or provides its own
rationales for why Texas might have rejected other RACMs not included
on the list to be considered in the future. The Act and EPA guidance
require the State to perform the required RACM analysis. EPA's role is
limited to reviewing what the states have submitted, and approving or
disapproving it. 42 U.S.C. 7410(k)(3); Riverside Cement Co. v. Thomas,
843 F.2d 1246 (9th Cir. 1988). EPA ``may either accept or reject what
the state proposes; but EPA may not take a portion of what the state
proposes and amend the proposal ad libitum.'' Id. If states are going
to reject control measures, their decision to do so and the rationale
therefore must be subject to notice and hearing at the state and local
level. This comment is essentially the same as a comment provided on
EPA's October 12, 2000 Notice of Availability proposing action
regarding RACM for the three serious areas of Atlanta, Washington DC
and Springfield, MA.
Response: In the case of the HG SIP, Texas has performed an
analysis of whether all RACM were included in the SIP. Based upon its
analysis, the State concluded that one additional measure not included
in the December 2000 SIP

[[Page 57183]]

submission, control of small liquid fired engines, was reasonably
available and therefore proposed and adopted a rule to control these
sources. Otherwise, the State concluded all RACM were in place. The
public did have a chance to comment at the State level on the State's
conclusion that no additional RACM were required. The EPA believes that
the State analysis was adequate. We reviewed the State's proposed
analysis and discussed our evaluation of it in the TSD for our July
2001 proposed action on the State's RACM analysis. The EPA did not
amend the SIP; EPA evaluated the State's analysis and for
transportation control measures, supplemented the State's rationale
with additional thoughts on why we believed the RACM analysis was
adequate. We explain in the TSD why we agree with the State that no
additional measures are RACM for the HG area and therefore the RACM
requirement of the Act is met.
The commenter cites Riverside Cement for the proposition that EPA
cannot perform an analysis of whether the State's plan complies with
the Act's RACM requirement. The EPA believes that the holding of that
case is inapplicable to these facts. In Riverside Cement, EPA approved
a control requirement establishing an emission limit into the SIP and
disregarded a contemporaneously-submitted contingency that would allow
the State to modify the emission limit. Thus, the court concluded that
EPA ``amended'' the State proposal by approving into the SIP something
different than what the State had intended. 843 F.2d at 1248. In the
present circumstances, EPA did not attempt to modify a substantive
control requirement of the submitted plan. Rather, EPA evaluated the
State's analysis plus performed additional analysis to determine if the
plan, as submitted, fulfilled the substantive RACM requirement of the
Act. As a general matter, EPA believes that States should perform their
own analyses of RACM (as well as submitting other supporting documents
for the choices they make), which is what Texas did in this instance
for the Houston area. The statute places primary responsibility on the
States to submit plans that meet the Act's requirements. However,
nothing in the Act precludes EPA from performing those analyses, and
the Act clearly provides that EPA must determine whether the State's
submission meets the Act's requirements. Under that authority, EPA
believes that it is appropriate, though not mandated, that EPA perform
independent analyses to evaluate whether a submission meets the
requirements of the Act if EPA believes such analysis is necessary. The
EPA has not attempted to modify the State's submission by either adding
or deleting a substantive element of the submitted plan. By virtue of
the State's analysis and EPA's evaluation of it, and EPA's supplemental
RACM analysis for transportation control measures, EPA has concluded
that the State's submission contains control measures sufficient to
meet the RACM requirement.
Comment: Inappropriate grounds for rejecting RACM. The commenter
claims that EPA's bases for rejecting measures as RACM are
inappropriate considerations: (a) The measures are ``likely to require
an intensive and costly effort for numerous small area sources''; or
(b) the measures ``do not advance the attainment dates'' for the areas.
65 FR 61134. Neither of these grounds are legally or rationally
sufficient bases for rejecting control measures. This comment is
essentially the same as a comment provided on EPA's October 12, 2000
Notice of Availability proposing EPA's RACM action for the three areas
of Atlanta, Washington D.C. and Springfield, MA.
Response: The EPA's approach toward the RACM requirement is
grounded in the language of the Act. Section 172(c)(1) states that a
SIP for a nonattainment area must meet the following requirement, ``In
general.-- Such plan provisions shall provide for the implementation of
all reasonably available control measures as expeditiously as
practicable (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) and shall provide
for attainment of the national primary ambient air quality standards.''
[Emphasis added.]
The EPA interprets this language as tying the RACM
requirement to the requirement for attainment of the national primary
ambient air quality standard. The Act provides that the attainment date
shall be ``as expeditiously as practicable but no later than * * *''
the deadlines specified in the Act. EPA believes that the use of the
same terminology in conjunction with the RACM requirement serves the
purpose of specifying RACM as the way of expediting attainment of the
NAAQS in advance of the deadline specified in the Act. As stated in the
``General Preamble for the Implementation of Title I of the Clean Air
Act Amendments of 1990 (General Preamble)'' (57 FR 13498 at 13560,
April 16, 1992), ``The EPA interprets this requirement to impose a duty
on all nonattainment areas to consider all available control measures
and to adopt and implement such measures as are reasonably available
for implementation in the area as components of the area's attainment
demonstration.'' [Emphasis added.]
In other words, because of the
construction of the RACM language in the Act, EPA does not view the
RACM requirement as separate from the attainment demonstration
requirement. Therefore, EPA believes that the Act supports its
interpretation that measures may be determined to not be RACM if they
do not advance the attainment date. In addition, EPA believes that it
would be unreasonable to require implementation of measures that would
not in fact advance attainment. See 57 FR 13560. EPA has consistently
interpreted the Act as requiring only such RACM as will provide for
expeditious attainment since the agency first addressed the issue in
guidance issued in 1979. See 44 FR 20372, 20375 (April 4, 1979).
The term ``reasonably available control measure'' is not actually
defined in the definitions in the Act. Therefore, the EPA
interpretation that potential measures may be determined not to be RACM
if they require an intensive and costly effort for numerous small area
sources is based on the common sense meaning of the phrase,
``reasonably available.'' A measure that is reasonably available is one
that is technologically and economically feasible and that can be
readily implemented. Ready implementation also includes consideration
of whether emissions from small sources are relatively small and
whether the administrative burden, to the States and regulated
entities, of controlling such sources was likely to be considerable. As
stated in the General Preamble, EPA believes that States can reject
potential measures based on local conditions including cost (57 FR
13561). See Ober v. EPA, 84 F3d at 312 (9th Circuit 1996).
Also, the development of rules for a large number of very different
source categories of small sources for which little control information
may exist will likely take much longer than development of rules for
source categories for which control information exists or that comprise
a smaller number of larger sources. The longer time frame for
development of rules by the State would decrease the possibility that
the emission reductions from the rules would advance the attainment
date. Texas has determined and we agree that such additional measures
in the HG area could not be developed soon enough to advance the
attainment date.

[[Page 57184]]

Comment: Failure to quantify reductions needed to attain sooner:
Even if advancement of the attainment date were a relevant test for
RACM, EPA has failed to rationally justify its claim that additional
control measures would not meet that test. To begin with, neither the
Agency nor the states have quantified in a manner consistent with EPA
rules and guidance the emission reductions that would be needed to
attain the standard prior to achievement of emission reductions
required under the NO_X SIP call. Nowhere is there an
analysis that shows what it would take to attain in 2004, 2005, 2006 or
2007. This comment generally repeats a comment provided on EPA's
October 12, 2000 Notice of Availability proposing EPA's RACM action for
the three areas of Atlanta, Washington DC and Springfield, MA.
Response: First, note that while the commenter makes reference to
the NO_X SIP call, Texas is not included in the mandatory
NO_X SIP call. However, it should also be noted that even
though Texas was not included, Texas adopted control measures for
regional NO_X emissions reductions (including in attainment
areas) as part of the HG attainment demonstration SIP, in a manner
similar to those undertaken by the states included in the
NO_X SIP call. These regional reductions will occur by May
2003 in Texas. In Michigan v. EPA, 200 WL 1341477 (D.C. Cir. 2000)
(order denying motion to stay mandate pending appeal from 213 F.3d
663(D.C. Cir. 2000)) the court held the NO_X control measures
could not be required by EPA until May 31, 2004 in order to allow
sources in subject States 1309 days from the date of the court order to
implement the measures as provided in the original rule. These regional
measures in Texas are thus being implemented on a more expeditious
schedule and as expeditiously as is practicable.
Further, it would be futile for TNRCC to attempt to quantify the
emission reductions that could be possible for the HG area to attain
prior to the 2007 deadline. With all of the adopted control measures,
and with the enforceable commitments to achieve the additional 56 tons/
day of NO_X emission reductions needed for attainment, plus
the necessary reliance upon Federal measures, including the amount of
cleaner on and off-road vehicles that will enter the fleet, there are
simply no additional measures that EPA is aware of that are reasonably
available or economically feasible that could be implemented, much less
implemented in time, to achieve attainment in advance of when the
measures are being implemented in this plan.
The following respond to the issue of whether additional specific
potentially available measures are RACM for the HG area.
Comment: Inadequate RACM analysis: EPA's RACM analysis is grossly
inadequate in several key respects.
Comment a: EPA's analysis fails to provide the technical basis and
calculations by which it developed its emission reduction estimates for
various measures. EPA failed to provide citations to the literature
regarding estimates of emission reductions for various TCMs. EPA failed
to specify the level of implementation assumed for some of the TCMs in
the analysis.
Response a: First, note that EPA's analysis contained in the TSD
was intended to evaluate and in one instance supplement the TNRCC
analysis and conclusion that all RACM had been adopted. We evaluated
the TNRCC's technical basis and calculations for the emission reduction
estimates for controls possible for all of the source categories in the
emission inventory. Regarding the TCM category, we provided additional
technical analysis and calculations. The commenter apparently believes
EPA's analysis of potential TCMs as not being RACM for the HG area is
insufficient, however. EPA's technical basis for the supplemental TCM
RACM analysis and the assumptions used in the calculation of estimated
emission reductions from additional potential TCMs were derived from a
review of the literature on the implementation and effectiveness of
TCM's.\15\ The TCMs evaluated depend on the level of implementation.
Implementation variables, representing levels of implementation effort,
are implicit in the range of effectiveness for each category of TCM.
EPA does not believe it is necessary, or even practically possible, to
evaluate every explicit variation of TCM's in order to adequately
determine if it is reasonably available. In summary, the technical
basis is provided in Appendix B to the TSD and Chapter 7 of TNRCC's
SIP. In conclusion, we determined that at a reasonable level of
implementation, all potential categories of TCMs taken together would
not be sufficient to advance the attainment date.
---------------------------------------------------------------------------

\15\ Transportation Control Measures: State Implementation Plan
Guidance, US EPA 1992; Transportation Control Measure Information
Documents, US EPA 1992; Costs and Effectiveness of Transportation
Control Measures: A Review and Analysis of the Literature, National
Association of Regional Councils 1994.
---------------------------------------------------------------------------

Comment b: EPA's analysis looks at only a small universe of
potential measures, and does not evaluate all of the measures
identified in public comment and other sources. Several commenters
suggested that a variety of measures were Reasonably Available and
should be included in the SIP.
Response b: It is EPA's position that the TNRCC's RACM analysis
identified and addressed all potential categories of stationary and
mobile sources in the HG area, that could provide additional emission
reductions, and measures that might be considered RACM. The EPA
believes not only that Texas identified and addressed all the potential
source categories but that it also addressed identified measures raised
by commenters. The TNRCC considered a wide range of potential measures,
including all measures adopted in other severe and serious areas and
the California South Coast's extreme attainment demonstration SIP.
The following addresses specific measures that were suggested by
commenters.

VOC Control Measures

Comment: An adequate plan would emphasize reductions in all
precursors not just one.
Response: The two primary precursors to ozone are Volatile Organic
Compounds (VOCs) and Oxides of Nitrogen ( NO_X). These
classes of chemicals react in the atmosphere in the presence of
sunlight to form ozone. Under 182(c)(2), States must base their
attainment demonstration on photochemical modeling or any other
analytical method determined by EPA to be at least as effective.
Modeling is generally regarded as the most reliable basis for
ascertaining which precursors should be emphasized for control in order
to obtain a reduction in ozone concentration levels. In the HG area,
the photochemical modeling indicates that NO_X emission
reductions are much more effective in reducing ozone and thus,
NO_X emission reductions have appropriately been the emphasis
in the plan's control strategy. As discussed further in the next
comment/response, EPA agrees that no additional VOC measures would
advance the attainment date.
Future studies may revise the emphasis of the control strategy. EPA
is aware that some of the preliminary results of the Texas Air Quality
Study 2000 indicate that reactive VOC's may need to be considered for
additional control. Further, there is no clear evidence, at this time,
that indicates that the control of other pollutants, such as
particulate matter, would help in reducing the ozone concentration
levels in the HG area.

[[Page 57185]]

Comment: A commenter stated that TNRCC has not developed adequate
VOC controls. The document presents evidence that categories of
emissions representing the ``vast majority'' of point source emissions
are regulated but does not determine whether in fact the facilities are
regulated. The commenter felt the proper analysis would present an
inventory of controlled emissions and compare it with total emissions.
Response: EPA believes the analysis in Chapter 7 of the SIP and in
the TSD does demonstrate further VOC controls are not required as RACM
based on the information currently available. This conclusion is based
on three factors. First, EPA believes Texas has regulated all major
sources of VOCs in the HG area to at least a RACT level. We took action
on these RACT rules in separate Federal Register actions. We found that
the State had implemented RACT on all major sources in the HG area
except those that were to be covered by post-enactment Control
Technique Guidelines (CTGs)(60 FR 12437, March 7, 1995). Since that
time many expected CTGs were issued as Alternative Control Technique
documents--ACTs. Of the expected CTGs and ACT's, the HG area had major
sources in the following categories; batch processing, industrial
wastewater, reactors and distillation, and wood furniture. We have
approved measures for all of these categories as meeting RACT.

Batch Processing--July 16, 2001 66 FR 36913
Industrial Wastewater--December 10, 2000 65 FR 79745
Reactors and Distillation--January 26, 1999, 64 FR 3841
Wood Furniture--October 30, 1996, 61 FR 55894

Further, EPA agrees with the conclusion drawn by Texas in its RACM
analysis that the majority of VOC point source emissions (whether
emitted from major sources or minors) are already regulated by the
rules contained in Chapter 115 of the State Implementation Plan. The
State's VOC rules go beyond RACT level controls for some categories
such as fugitive emissions and gasoline loading emissions. EPA has
approved Chapter 115 as meeting the RACT requirements.
Second, because of the particular chemistry in the HG area VOC
controls are not nearly as effective as NO_X controls in
reducing ozone. TNRCC has demonstrated through modeling that 12-15
tons/day of VOC emission reductions are needed to achieve the same
ozone benefit as one ton/day of NO_X emission reductions as
shown in Chapter 7 of the October 2001 SIP revision. Thus, the
particular chemistry in the HG area makes additional ozone benefits
very difficult to achieve through VOC reductions. In fact, modeling
indicates that if all man made VOC's were reduced to zero, the area
would not reach attainment.
Third, Texas analyzed the controlled VOC inventory to determine if
any source categories remained where additional VOC controls could be
implemented that could advance the attainment date in light of the
modeling evidence. As discussed previously, EPA does not believe that
section 172(c)(1) requires implementation of potential RACM measures
that will not be sufficient to allow the area to achieve attainment in
advance of full implementation of all other required measures, in this
case, full implementation of the NO_X controls called for in
the plan including the 56 tons/day NO_X reductions called for
by the enforceable commitments. In the TNRCC analysis, a VOC source
category had to have at least 12-15 tons per day of emissions to
warrant further analysis. This level was chosen because it might be
theoretically possible to reduce these categories enough to achieve as
much as the equivalent of one ton/day of NO_X reduction.
Given that the final 121 tons/day of point source reductions, out of a
total of almost 600 ton/day of emission reductions, will not be
implemented until spring 2007 emission reductions from measures that
achieve less than the equivalent one ton/day of NO_X
reductions even if combined with several measures of similar magnitude
cannot advance the attainment date. The TNRCC presents in the SIP
Narrative, Chapter 7, a summary of the inventory that reflects the
controlled level of emissions. Based on the above screening level one
category, storage tanks, was examined for additional control. Based on
controls in the Alternative Technique Guideline, only 2.2 tpd of
additional reduction in VOC could be achieved which is far less than
the equivalent of one ton/day of NO_X reduction and therefore
would not advance attainment.
Texas also reviewed all VOC area source (as opposed to points
source) categories to see if any categories were emitting greater than
11 tons/day in emissions. While some area source categories emitted
more than 11 tons/day, these categories already are subject to rules.
TNRCC did not believe additional controls on already regulated
categories would be reasonable in light of the amount of VOC reductions
needed to achieve ozone benefits.
In summary, the modeling indicates that it takes substantial VOC
emission reductions to achieve ozone reductions in the HG area. Already
all major sources of VOC's in HG have RACT in place. Emission
reductions beyond RACT on major VOC sources may be achievable but could
not achieve sufficient ozone benefit for the HG area to achieve
attainment in advance of the measures in the SIP we are approving
today. Significant area source categories are also regulated.
Therefore, no emission reduction measures were identified that would
achieve attainment in advance of the measures contained in the plan.
Comment: For States that need additional VOC reductions, this
commenter recommends a process to achieve these VOC emission
reductions, which involves the use of HFC-152a (1,1 difluoroethane) as
the blowing agent in manufacturing of polystyrene foam products such as
food trays and egg cartons. HFC-152a could be used instead of
hydrocarbons, a known pollutant, as a blowing agent. Use of HFC-152a,
which is classified as VOC exempt, would eliminate nationwide the
entire 25,000 tons/year of VOC emissions from this industry.
Response: This comment was not provided to TNRCC. EPA has met with
the commenter and has discussed the technology described by the company
to reduce VOC emissions from polystyrene foam blowing through the use
of HFC-152a (1,1 difluoroethane), which is a VOC exempt compound, as a
blowing agent. Since the HFC-152a is VOC exempt, its use would give a
VOC reduction compared to the use of VOCs such as pentane or butane as
a blowing agent. However, EPA has not studied this technology
exhaustively. It is each State's prerogative to specify which measures
it will adopt in order to achieve the additional VOC reductions it
needs. In evaluating the use of HFC-152a, States may want to consider
claims that products made with this blowing agent are comparable in
quality to products made with other blowing agents. Also the question
of the over-all long term environmental effect of encouraging emissions
of fluorine compounds would be relevant to consider. This is a
technology which States may want to consider, but ultimately, the
decision of whether to require this particular technology to achieve
the necessary VOC emissions reductions must be made by each affected
State. Finally, EPA notes that under the significant new alternatives
policy (SNAP) program, created under CAA Sec. 612, EPA has identified
acceptable foam blowing agents many of which are not VOCs (http://
www.epa.gov/ozone/snap/index.html).

[[Page 57186]]

In the case of the HG area, the analysis in chapter 7 did not show
this category of emissions as one with more than 11 tons/day of
emissions so, as discussed in a previous comment, there cannot possibly
be enough emission reductions from this category to achieve sufficient
ozone benefit for the HG area to reach attainment in advance of the
full implementation of the measures in this SIP.
Comment: Two commenters suggested that a portable gasoline
container buy back program should be adopted in the HG area to
introduce gasoline containers meeting the California Air Resources
Board (CARB) standards to the HG area. It was estimated based on CARB
experience that controls on containers would be able to achieve 23 tpd
of VOC reductions in the HG area.
Response: This measure was suggested to TNRCC as a replacement to
their Commercial Lawn Service operating restrictions. TNRCC evaluated
the measure and decided the measure would not achieve equivalent
reductions to the operating restrictions.
EPA is aware that CARB has projected significant emission
reductions from this measure. This is based on their studies of the
emissions from evaporation and spillage from gasoline containers in
California. TNRCC in their RACM analysis of the HG emission inventory,
however, did not identify this source category, i.e., gasoline
containers, as having the same level of emissions and therefore the
potential to achieve the same level of emission reductions as was found
in California. TNRCC used EPA approved methodology to develop its
inventory. EPA concludes, based on the record supporting the State's
RACM analysis, that Texas used appropriate assumptions for determining
emission reductions from this measure. Based on the emission estimates
contained in the approved inventory, EPA agrees with Texas that this
measure cannot be considered RACM at this time because the measures
cannot achieve sufficient ozone benefit for the HG area to achieve
attainment in advance of the full implementation of the measures in the
SIP we are approving today. Future study of this portion of the
inventory utilizing information developed by CARB may indicate that
more emissions arise from this category in the HG area and this measure
may have to be revisited.
Comment: One commenter pointed to the results of the Channelview
Source Reduction Project as evidence that significant levels of VOC
emission reductions can be achieved. The Channelview Project resulted
in the following improvements: Additional gas flow meters, reduced
flaring of off-spec product, elimination of flaring of extra-contract
product, improved flare systems, and prevention of unnecessary
shutdowns.
Response: The November 14, 2000 ``Source Reduction Project, Report
on Phase I'' documents the cooperative effort between the Community
Advisory Panel and Lyondell and Equistar (CAPLE) to reduce air
emissions at these companies. It documents several improvements and
significant emission reductions that have been made at these plants
through focusing on source reduction. It is not clear from the report,
however, whether or not the measures instituted by these companies have
general applicability within the chemical industry. The measures taken
by these companies to reduce emissions have promise as measures that
can achieve emission reductions throughout the HG area but it will take
further study by us and the State to determine if they can be applied
to other facilities, are technically and economically feasible and
achieve reductions that could advance attainment, and thus can be
considered potential RACM for the HG area. Therefore, at this time, EPA
cannot find these measures feasible. EPA agrees with Texas that this
type of project cannot currently be considered RACM.
Comment: One commenter suggested that the State should reduce
fugitive VOC emissions by 90%.
Response: The commenter did not suggest how the 90% emission
reduction from fugitive VOC emissions could be achieved. EPA is not
aware of any technology or programs that have been demonstrated to
achieve this level of reductions. TNRCC already has in place a leak
detection and repair requirement that goes beyond the levels in EPA's
control technique guidelines to control refinery and chemical plant
fugitive emissions. EPA has approved this requirement for fugitive
emissions as meeting the RACT requirement for the HG area. Based on the
above, EPA concludes that this measure is not technically feasible at
this time.
Upset Emissions
Comment: TNRCC has failed to adopt reasonably available control
measures for controlling upset emissions because the TNRCC rules fail
to meet at a minimum EPA guidance for upset emissions. The rule
violates the requirements regarding creating an affirmative defense
because (1) it is a blanket exemption, (2) it covers sources whose
individual contributions of pollutants have the potential to cause an
exceedence, (3) it covers both penalties and injunctive relief, and (4)
it could be interpreted as barring citizen and/or EPA enforcement
action.
Response: On November 28, 2000, EPA issued a direct final approval
of a revision to the Texas SIP addressing excess emissions from start-
up, shutdown, malfunction and maintenance. 65 FR 70792. In that notice,
EPA explained that it determined that the rule was consistent with the
EPA guidance referenced by the commenter, ``State Implementation Plans:
Policy Regarding Excess Emissions During Malfunctions, Startup and
Shutdown,'' September 20, 1999. This determination included EPA's
conclusion that the Texas rule does not provide an exemption from
compliance for periods of excess emissions. No adverse comments were
received and EPA's approval became effective on January 29, 2001.
Through the proposed actions on which EPA is taking today, EPA is not
re-opening its past approval of SIP requirements. Thus, the commenters
attempt to now raise issues about whether EPA's approval of that rule
was appropriate are untimely.

Point Source NO_X Controls

Comment: The Phase II NO_X limits agreed to by OTC States
are clearly RACM for all areas, as they are widely in effect. States
that have not adopted such measures have not adopted enforceable
NO_X RACT limits for all relevant facilities. It is not
sufficient for States to assert that they will adopt additional
NO_X controls if needed.
Response: That the OTC states have implemented the OTC Phase II
NO_X limits does not automatically prove that these limits
are RACM for all areas. EPA concedes that the wide-spread adoption of
such programs and EPA's own analysis of NO_X control on large
stationary sources would warrant consideration whether such limits meet
the technological and economical feasibility criteria of RACM and would
advance attainment. However, such an analysis is not relevant in the
case of the HG ozone nonattainment area. Texas has already adopted
programs for the HG area to implement limits that are more stringent
than the OTC Phase II limits.
Comment: A commenter suggested energy efficiency improvements are
not just for residential and commercial buildings and suggested savings
could be achieved by more efficient motor and drive systems.
Response: We agree that improved energy efficiency is a desirable
method of reducing air emissions. There are difficulties in including
such measures in a SIP because it is not always clear

[[Page 57187]]

where the benefits of the reduced electrical demand will occur. The
reduced demand could result in emission reductions outside the HG area.
There are initiatives in Texas to reduce growth in demand in Texas such
as the State wide building codes established by Senate Bill 5. The
State of Texas has committed to further examine the benefits and
methods of improving energy efficiency for possible inclusion in the
SIP at the mid-course review. EPA concludes that there is not enough
information at this time to determine the appropriate emission benefits
and therefore energy efficiency cannot currently be considered RACM.
Comment: Just as Integrated Resource Planning (IRP) for electric
utilities resulted in demand side management programs that conserved
electricity, IRP for natural gas utilities will have the same impact on
conserving natural gas usage and resulting emissions. A number of
states have effectively implemented IRP for natural gas.
Response: As noted above, EPA agrees that improved energy
conservation-regardless of the form of energy-is a desirable method of
reducing air emissions. Since such measures would likely have to rely
on voluntary efforts, the State would have to estimate the effect on
emission reductions that would result. Putting in place even a
voluntary effort to conserve natural gas that could be quantified in
terms of its emission reduction benefits would likely require a
significant amount of time. EPA is aware that the State had devoted a
tremendous amount of resources in developing and adopting the number of
control measures that it did for the HG area's one-hour ozone SIP, and
even with that had to commit to fill a shortfall of 56 tons/day of
NO_X reductions. EPA believes it is unlikely-given the time
spent on the bulk of the SIP-that the State had the time to develop
such a quantifiable voluntary program that would have yielded enough
NO_X reductions to advance the attainment date. Furthermore,
it appears unlikely that such a quantifiable program could be put into
place in sufficient time to advance the attainment date given the
resources that the State will have to spend over the next several years
simply developing and adopting the emission controls to achieve the 56
tons/day NO_X emission reductions. Therefore, EPA believes
that this measure is not RACM, at this time, for the HG area.
Comment: Stringent Standards for Stationary Diesel Engines: The
TNRCC should establish the same requirements for new and existing
stationary diesel engines in the HG area that are not used exclusively
during infrequent emergency or backup situations.
Response: The State received a similar comment. In their response
they explained that based on information in the emissions inventory and
contact with diesel engine vendors and others familiar with the
stationary diesel engines in the HG area, the State is unaware of any
existing stationary diesel engines that are being operated in
situations other than generation of electricity in emergency situations
or operation for maintenance and testing. The Chapter 117 rule requires
that all testing and maintenance be done outside the hours of 6 am to
12 am. As discussed in the comments on the modeling inputs, emissions
in the morning are the most conducive to ozone formation. Emissions
outside this period are much less conducive to ozone formation.
Therefore, the rules for maintenance represent RACM for the HG area.
TNRCC believes and EPA agrees that few existing engines will be
moved from emergency service to routine or peak shaving operations for
the following reasons. Any existing engines at a site with a collective
design capacity to emit (from units with chapter 117 emission limits)
greater than ten tpy of NO_X are subject to the Chapter 101
mass emissions cap and trade program if they choose to increase their
operation to 100 hours per year or more (based on a rolling 12-month
average) and, in addition to having to comply with the Chapter 117
rules, will only be issued NO_X emissions allocations based
on their historical activity level which would be much lower than 100
hrs/year. Existing engines theoretically could be switched to peak
shaving service up to 100 hours/year but in reality only about 40
hours/year would be available for this type of operation. The remaining
time would have to be used for normal routine testing of the engines.
It is unlikely that the profit from sale of electricity, would justify
the cost of the modifications to the switching system for only about 40
hours of operation. EPA concludes that additional control beyond the
existing program is not economically feasible and therefore would not
represent RACM.

On-Road Control Measures

Comment: Two commenters suggested that 15 ppm sulfur gasoline
should be adopted in the HG area as a reasonably available control
measure.
Response: The Act preempts states from establishing state fuels
under section 211(c)(4)(A). Waivers from preemption are possible under
section 211(c)(4)(C) if the state can show necessity for that fuel to
meet the NAAQS, and if no other reasonable or practicable non-fuel
measures exist that could be implemented in place of a state fuel. For
a state to obtain a waiver of preemption, an acceptable demonstration
must be submitted to EPA that can justify the need for a particular
state fuel. This provision of the Act was included to discourage the
development of a patchwork of fuel requirements from State to State.
Texas considered adopting a 15 ppm sulfur standard in gasoline, but
withdrew the proposal once the 30 ppm Federal low sulfur gasoline
standard became final. They received comments both for and against the
proposal. Comments against cited excessive costs when compared with the
emissions benefit, the difficulties in producing a boutique fuel, and
anticipated distribution problems and conflicts with on-going efforts
to comply with the federal low-sulfur requirements of 30 ppm. Texas
only projected a 1.15 ton/day of emission reduction from the
institution of a 15 ppm fuel. The BCCA estimates that the cost of these
reductions is $400,000/ton to refiners. Based on TNRCC cost estimates,
the cost is over $500,000/ton to consumers.
Because of the general preemption in the Act and the low projected
cost effectiveness, EPA does not consider this fuel requirement to be
RACM for the HG area.
Comment: One commenter suggested that Texas adopt diesel fuel that
meets a 15 ppm sulfur standard by 2003.
Response: Texas adopted a low emission diesel fuel in December
2000, that includes a low sulfur component. The state's low sulfur
component phases in beginning May 1, 2002, with 500 ppm sulfur
statewide for on-highway use and 110 counties in east and central Texas
for non-road use. On June 1, 2006, the sulfur level drops to 15 ppm in
east and central Texas for off-highway use to be consistent with
Federal low sulfur diesel fuel for on-highway use. Thus, TNRCC has
already adopted a standard more stringent than the Federal Standards.
In order for Texas to adopt statewide fuel controls that are more
stringent than Federal controls, the state must show necessity to
achieve the NAAQS in the nonattainment areas and justify implementing a
fuel measure over nonfuel measures statewide. Texas has requested and
EPA is granting in a separate Federal Register a waiver under
211(c)(4)(A) for this fuel. EPA does not believe the accelerated
schedule of implementing the low sulfur standard suggested by the
commenter is reasonable or will result

[[Page 57188]]

in ozone benefits because the low sulfur requirement does not result in
NO_X emission reductions by itself but instead enables
catalyst technologies. Under Federal regulations, new vehicles will not
be required to meet the new emission standard enabled by low sulfur
diesel until 2007. Therefore, EPA does not consider calling for these
fuel requirements earlier as suggested by the commenter to be RACM.
Comment: Two commenters gave comments that the Inspection and
Maintenance Program could be improved. One said that adequate resources
to develop and implement an I/M program must be assigned; otherwise,
the program cannot be considered credible. A second commenter stated
that the program should be established based on where the vehicle owner
usually works.
Response: EPA has reviewed the I/M program developed by the State
of Texas. In a separate Federal Register notice, we are approving the
State's I/M program. The new program, using the Accelerated Simulation
Mode (ASM) test method will be implemented in all eight counties of the
HG nonattainment area and covers more vehicles than are required by the
Federal I/M rules. Expanding the program to cover vehicles not
registered in the program area is beyond the scope of the Federal rules
and would be extremely difficult to implement and enforce. Further, the
prior, less stringent program met the minimum I/M requirement for the
HG area. The new program goes beyond those requirements. As such, we
believe TNRCC has adopted an I/M program that meets the RACM
requirement. We agree that adequate resources will have to be devoted
to the implementation of this program by the Texas Department of Public
Safety and TNRCC for the goals of the program to be achieved. At this
time, we have no information to support a determination that the
program will not be fully implemented.
Comment: One commenter suggested that public and large commercial
fleets be required to have low emitting vehicles.
Response: Texas adopted Fleet provisions and submitted them to EPA
on August 27, 1998 as the Texas Clean Fuel Fleet (CFF) substitute plan.
EPA approved this provision on February 7, 2001 (66 FR 9203) as meeting
the Clean Fuel Fleet Requirements of the Act. These provisions ensure
that fleets meet a reasonable level of control in serious and above
nonattainment areas. Texas' CFF substitute plan relies on a State fleet
program--the Texas Clean Fleet (TCF) program--supplemented with
additional volatile organic compound (VOC) and nitrogen oxide
(NO_X) emission controls. The emission reductions for Texas'
plan greatly exceed the reductions that would have been achieved with
the Federal CFF program. Therefore, the State's substitute plan will
meet the Federal CFF requirement for VOC and NO_X emissions
reductions. EPA believes that TNRCC has instituted RACM for this source
category.
Comment: One commenter suggested that the State should encourage
the early introduction of Tier 2 vehicles.
Response: In the last session, the Texas legislature passed Senate
Bill 5 which includes an incentive program for the purchase of vehicles
that meet the more stringent Tier II vehicle standards. This program
should result in more cleaner vehicles coming into use in Texas then
would be required under the Federal Program. It is uncertain, however,
how much additional emission reduction will come from this program as
it apparently is the first of its kind in the country. Therefore, EPA
concludes that further acceleration of this program would not
constitute RACM for the HG area.
Comment: A commenter suggested that non-USA registered trucks
should be subject to an I/M inspection.
Response: It is not clear whether the State has the legal authority
to require trucks from a foreign country to be inspected. As a
practical matter, there are no proven test methods to employ for Diesel
I/M programs. Therefore, this cannot be considered a reasonably
available measure.
Comment: One commenter felt all highway construction in HG area
should be limited. The HG area must absorb on-going expansions at the
airports, medical center plus population and job growth. There is no
room for the above ongoing new emissions generating projects let alone
any new large emissions generating projects. The same commenter later
said that the Transportation Improvement Plan and other proposed
changes to Regional Highway system must demonstrate full conformity
with the Act.
Response: EPA agrees that the Regional Transportation Plans must
demonstrate conformance to the State Implementation Plan consistent
with section 176(c) of the Act and our transportation conformity rules
at 40 CFR 93.100; however, these are separate requirements from
demonstrating attainment of the NAAQs. Transportation conformity is the
process whereby the transportation plans have to be reconciled with and
show they are consistent with the plans for attainment. In this SIP,
the State has established an emissions budget for motor vehicle
emissions consistent with attainment. The Houston/Galveston Area
Council will have to show for all future plans, taking into account
existing roads and future growth how they will conform to these
budgets. Given the severe impact a ban on road construction would place
on the HG area, EPA concludes that this is not a reasonably available
measure.
Comment: One commenter suggested the State institute an auto
license fee tied to actual vehicle NO_X emission rates.
Response: EPA is not aware of anywhere where this measure has been
instituted. It is not clear how much emission reductions could be
achieved and at what fee levels. Because of the lack of localized
information on the costs and benefits of this program this cannot be
considered a RACM.
Texas is already instituting a program to provide rebates for the
purchase of vehicles meeting the cleanest Tier II standards. This
program should influence positively the introduction of cleaner
vehicles into the fleet.

Off Road Measures

Comment: Three commenters recommended measures they felt were
appropriate to control emissions from construction equipment. One
commenter felt that all diesel equipment should be required to
register. He felt this would result in a 70% reduction in emissions.
Two other commenters felt that all State and Local Government contracts
should have requirements that require lower emission equipment be used.
Response: The Texas legislature has passed an incentive program
that will pay for the cost of upgrading diesel equipment to meet
cleaner standards. Texas plans to direct 24.7 million dollars/year to
the HG area from the Texas Emission Reduction Program passed under
Senate Bill 5. Based on experience from similar programs in California,
we expect substantial reductions to be achieved. We therefore believe
that additional measures to reduce emissions from this category are not
RACM.
Comment: One commenter suggested the following measures to achieve
additional emission reductions from aircraft operations: (1) Mandatory
Powering of Jets at gates with Electric Power (2)Reduced Idling on the
runway (3) Congestion Pricing at Rush Hours at Airports.
Response: First, the State has executed agreed Orders with the
major airlines and the City of Houston to achieve emission reductions
from Ground Support Equipment (GSE) at

[[Page 57189]]

airports in the HGA area. These Orders require a phased-in replacement
of current combustion engine equipment with electric equipment or to
achieve equivalent reductions. Equipment powering jets at gates is
included in the definition of GSE; thus, over a period of time jets at
gates will be powered with electric equipment or equivalent emission
reductions will be achieved. Second, although planning of airline
operations during rush hours to reduce idling on runways to reduce
emissions may have merit, the State does not have the authority to
impose regulations on airlines to require this planning. The Federal
Aviation Administration has jurisdiction over airline operations once
the aircraft leaves the gate and State regulation is pre-empted. Third,
since the State has no authority to control airline operations, and
congestion is a function of the higher level of operations during rush
hours, congestion pricing is likely to place an unnecessary economic
burden on the traveling public with no air quality benefits. State
controls on pricing are expressly preempted by the Air Deregulation
Act. Therefore, EPA concludes that such measures are not reasonably
available.

Transportation Control Measures and Land Use

Comment: Transportation Control Measures as RACM: EPA gives
virtually no consideration to the emission reduction benefits of
transportation programs, projects and services contained in adopted
regional transportation plans (RTPs), or that are clearly available for
adoption as part of RTPs adopted for a nonattainment area. In addition,
it is arbitrary and capricious for EPA not to require as RACM economic
incentive measures that are generally available to reduce motor vehicle
emissions in every nonattainment area. One commenter provided a report
``Studies on the Travel and Air Quality Effects of Transit, Land Use
Intensification, and Auto Pricing Policies.'' The commenter felt this
report contained measures that are RACM.
Response: A similar comment was received in response to the
analysis EPA performed as part of EPA's notice of availability where an
analysis of Reasonably Available TCMs was performed for four serious
ozone nonattainment areas: Greater Connecticut, Springfield, MA,
Washington, DC and Atlanta. In the Technical Support Document for the
July 12, 2001 proposal on RACM, EPA performed a similar analysis for
the HG area. This analysis was performed to evaluate the State's
conclusion that further TCMs are either economically infeasible or
would not advance attainment.
EPA's TSD for the July 12, 2001 proposal on RACM for the HG area
does consider transportation programs, projects and services that are
generally adopted, or available for inclusion in a nonattainment area's
SIP. The RACM analysis includes seven broad categories and twenty-seven
subcategories of Transportation Control Measures (TCMs) that represent
a range of programs, projects and services. The inclusion of a TCM in
an RTP or TIP does not necessarily mean that it meets EPA's criteria
for RACM and must be included in the SIP. The measure must also
contribute to expeditious attainment. EPA concluded from its analysis
that the State's assertion that further TCMs are not RACM was
appropriate.
Some of these TCMs, such as parking cashout, transit subsidies, and
parking pricing, are explicitly economic incentive programs.
Furthermore, these categories of TCMs, as well as most of the others,
could be infinitely differentiated according to criteria, such as the
method of implementation, level of promotional effort or market
penetration, stringency of enforcement, etc. The application of
economic incentives to increase the effectiveness of a TCM is one such
criterion. These implementation variables, representing levels of
implementation effort, are implicit in the range of effectiveness for
each category of TCM. EPA does not believe it is necessary, or even
practically possible, to evaluate every explicit variation of TCM's in
order to adequately determine if it is reasonably available.
From the analysis for the HG area, EPA identified 1.7 to 22.4 tpd
of NO_X emission reductions as theoretically achievable from
TCMs. The EPA believes that emission reductions which are in the low-
to mid-point range of EPA's analysis are achievable with careful
planning, adequate implementation resources, aggressive public
information programs and a sustained commitment by the implementing
agencies. TNRCC has identified in its SIP the implementation of a wide
range of TCMs which are projected to achieve 4.86 tpd of emission
reductions. The TCM's identified in the HG analysis are in the low- to
mid-point range. Additional emission reductions beyond this level that
could be reasonably achieved would not advance attainment given that
the final 121 tons/day of NO_X emissions reductions from the
point source rules will not be achieved until spring of 2007.
There are many important reasons why a state, regional, or local
planning agency might implement TCMs in an integrated traffic
management plan beyond whatever air quality benefits the TCMs might
generate, including preserving open space, water shed protection,
avoiding sprawl, mitigating congestion, and ``smart growth'' planning
generally. So the fact that TCMs are being implemented in certain ozone
nonattainment areas does not necessarily lead one to the conclusion
that those TCMs represent mandatory RACM when they are analyzed
primarily for the purpose of determining whether they would advance the
ozone attainment date.
The report, ``Studies on the Travel and Air Quality Effects of
Transit, Land Use Intensification, and Auto Pricing Policies,''
provides case studies from two areas of the country, Portland OR, and
Sacramento, CA and a literature survey. EPA's analysis included
consideration of measures in the same categories as provided in this
report. Based on this analysis, EPA does not believe implementation of
these measures would advance the HG area's attainment. Further, as
stated in the General Preamble, 57 FR 13560, EPA believes that local
circumstances vary to such a degree from city-to-city that a national
presumption of RACM is not appropriate. It is more appropriate for
States to consider TCM's on an area-specific basis and to consider
groups of interacting measures, rather than individual measures.
Therefore, based on EPA's analysis, EPA cannot conclude that these
measure suggested in the report are RACM for the HG area.
Comment: A number of specific TCMs and economic incentive programs
to reduce vehicle miles traveled were identified by various commenters.
These include: Telecommuting, satellite offices, college/university
traffic control measures, Bike and Walk pathways, Increased Government
Use of the Web, Voluntary No Drive Days, Trip Reduction Ordinances,
Employer Based Transportation Management, Road Pricing, Ride Share
Incentives, Insurance Pricing, Commuter Choice, Parking Cashout, Taxes
on Paid Parking, Congestion Pricing, Location Efficient Mortgages, Fee
Bate on Suburban Mortgages, Tax Incentives for Living Near Place of
Employment, Incentives for Transit Oriented Development and improved
incident response.
Response: As stated in the previous response, EPA does not believe
it is necessary, or even practically possible, to evaluate every
explicit variation of

[[Page 57190]]

TCM's in order to adequately determine if it is reasonably available.
EPA notes that many of the measures listed above are being encouraged
in the HG area as part of the commuter choice program such as
telecommuting, ride share incentives, and employer based transportation
management. As discussed in the previous comment Texas has identified
4.83 tpd of NO_X emission reductions from reasonably
available Transportation Control Measures which, based on the
literature survey, falls into the low to midpoint of emission
reductions theoretically achievable from these programs. Also, as noted
above, this small amount of emissions reductions would not advance
attainment prior to the implementation of all other measures in the
plan. Therefore, EPA believes the small amount of additional reductions
that could reasonably be achieved would not advance attainment.
Comment: EPA's analysis also completely fails to consider the
additional benefits likely from combined implementation of
complementary TCMS e.g., parking management along with transit
improvements. It is arbitrary and irrational for EPA to assume that
these measures can and will be implemented in complete isolation from
one another.
Response: EPA recognizes that many control measures, particularly
TCMS, are more effective if done in conjunction with others. EPA
maintains, however, that it is not practically possible to analyze a
seeming infinite set of combinations of measures for possible benefits.
The EPA's analysis did look at all measures in various categories at a
reasonable level of implementation and concluded that as a whole these
categories of measures, taken together, would not advance attainment or
would otherwise not be reasonably available.

General RACM Comments

Comment: One commenter suggested that the SIP should include
enforcement of New Source Review such that grandfathered plants would
get emissions permits with emission limits that are identical to new
construction as of June 2001.
Response: Existing industrial sources in the HG area are required
to comply with Chapter 115 for VOC and Chapter 117 for NO_X
controls regardless of whether the sources are permitted or
grandfathered. These rules have been approved as RACT. In addition all
sources, both existing and new, are subject to the NO_X mass
emissions cap in Chapter 101. Requiring all existing sources to obtain
permits is not likely to result in any additional emission reductions
beyond those achieved by the Chapter 115 and Chapter 117 rules.
Comment: One commenter incorporated in their comments to EPA their
comment to the TNRCC where they encouraged the State to use Market
Incentives to the extent possible.
Response: We believe the State has employed market based incentives
in a variety of programs. The cap and trade program and the Texas
Emission Reduction Program are the two main examples of programs that
use markets to provide significant flexibility in how emission
reductions are achieved.
Comment: STAPPA's 1993 report recommended adoption of California or
South Coast Air Quality Management District (SCAQMD) controls/limits
for various source categories. The commenter mentions further possible
control measures as well, and notes that none of the states offered
consideration of these measures accompanied by reasoned explanations
for their rejection.
Response: Texas used the EPA survey ``Serious and Severe Ozone
Nonattainment areas: Information on Emissions Control Measures Adopted
or Planned and Other Available Control Measures'' as a basis to
determine if all reasonably available control measures had been
implemented. This report includes measures from the STAPPA 1993 report
and other measures that EPA considers potentially reasonably available.
TNRCC did not identify any additional measures that were considered
reasonable for the HG area.
Comment: By absorbing ozone and reducing air temperatures, trees
actually account for a small but measurable reduction in ozone levels.
The EPA should work with TNRCC to encourage public funding for tree
planting and local ordinance that require canopy cover in new private
development.
Response: EPA agrees that tree planting can result in a possible
reduction in ozone formation. Unfortunately, at this time, these
benefits are difficult to quantify. Efforts are currently underway to
complete a modeling study to quantify the impacts of various urban heat
island mitigation strategies using the photochemical model. It is hoped
that these studies will provide information that will allow tree
planting strategies to be included as a creditable portion of the SIP
at a later date, perhaps for the mid-course review SIP submission.
Texas is involved in this effort and intends to incorporate such
programs in the SIP should they prove effective and reasonably
available.

C. Response to Comments on Local Measures

1. Comments on Speed Limits
Comment: Three commenters indicated the speed limit measure would
not be enforced or was not enforceable and that EPA should not give
credit unless TNRCC develops a mechanism to demonstrate that speeds
actually decrease.
Response: The mechanism to enforce reduced speed limits is already
in place with the Department of Public Safety and local municipalities.
EPA acknowledges that it is unlikely that 100% of vehicles will comply
with the new speeds. The modeling projections assume that the average
speed will be 10% higher than the posted speed limits on roads that
currently have average speeds above the reduced speeds. Thus, the State
has made reasonable assumptions to anticipate the level of compliance
with this rule. We believe we can approve these reasonable planning
assumptions about speed reductions. It would not be appropriate to wait
until Texas proves that the speeds have been reduced to give credit for
this measure just as we would not wait until industrial sources have
accomplished their emission reductions before approving point source
rules. We do believe that the effectiveness of this measure, as with
all measures, should be monitored. Data is collected in the HG area by
Transtar and Texas Department of Transportation. This data could be
used to evaluate the efficacy of this measure in reducing speeds.
2. Comments on the VMEP
Comment: The plan includes impermissible reductions for ``Voluntary
controls.'' EPA has no legal basis for issuing SIP credit for the VMEP
program; the VMEP measures do not meet the test of being real,
permanent, and enforceable to qualify for emission reductions.
Response: EPA disagrees with the comments, and continues to believe
that the voluntary measures proposed by Texas for inclusion in the SIP
are approvable under the Act. EPA acknowledges that, by themselves, the
measures would not be approvable, because, as noted by the commenter,
they are not enforceable against the entities producing the emissions
reductions and thus do not meet the enforceability requirement of
section 110(a)(2)(A). However, EPA did not propose to approve the
measures by themselves. EPA proposed to approve them only in
conjunction with an enforceable commitment by the state of Texas to
monitor implementation of the

[[Page 57191]]

voluntary measures, determine whether the anticipated reductions from
the measures were in fact achieved, and if not to either alter the
program such that the requisite reductions will be achieved, adopt
substitute measures, or demonstrate that the attainment and maintenance
goals of the ozone SIP can still be met without the reductions from
these measures. Thus, EPA did not propose to approve voluntary measures
as satisfying the enforceability requirements of section 110. Rather,
EPA proposed to approve the voluntary programs into the SIP as part of
the overall attainment scheme, and proposed to approve the state's
enforceable commitment to monitor, assess, and rectify any shortfall as
meeting the enforceability requirements of the Act.
EPA continues to believe that this approach is a proper means of
encouraging implementation of innovative mobile source control measures
while providing an enforceable SIP backstop measure. Ideally, the
voluntary measures will produce the estimated emissions reductions
without need for any state backfill or federal or citizen enforcement.
However, should any shortfall result, Texas will be bound by the
enforceable SIP commitment to rectify the problem and supply the
necessary emissions reductions. Both EPA and private citizens retain
all of their rights under sections 113 and 304 to bring appropriate
enforcement pressure to bear against the state should Texas fail to
monitor, assess or fill any shortfall in emissions reductions resulting
from implementation of the voluntary measures in the SIP. Contrary to
the commenter's allegations, the emissions reductions associated with
the voluntary measures in the HG area SIP are required to be achieved;
it is however the state and not the individuals implementing the
voluntary measures who must ultimately produce them.
Comment: Two commenters raise numerous arguments concerning the
unenforceability of the voluntary measures.
Response: The commenter makes no mention of the enforceable state
commitment other than to refer to it as insufficient. This statement
without further explanation does not give EPA any guidance on the
alleged inadequacy of the commitment nor how the commenter would have
EPA improve upon it. Therefore, EPA continues to maintain that the
commitment is approvable as meeting the enforceability requirements of
the Act. In the past, EPA has often approved enforceable state
commitments to take future actions under the SIP, and these actions
have been enforced by courts against states that have failed to comply
with those commitments.\16\ EPA believes that the Texas commitments
associated with the voluntary measures portion of the SIP are similarly
enforceable and thus approvable. NRDC alleges that the Act requires all
control measures to be enforceable against individual polluters and not
just against states. However, many mobile source control measures are
enforceable only against the state or local transit operator, and not
the individual entities actually producing the emissions reductions,
for instance in the case of state obligations to establish vehicle
inspection and maintenance programs or to purchase buses or expand
transit systems. The Act does not require federal enforcement
capability against individual vehicle owners or transit users prior to
approval of such programs into the SIP.\15\
---------------------------------------------------------------------------

\16\ See, Trustees for Alaska v. Fink, 17 F. 3d 1209 (9th Cir.
1994); Coalition Against Columbus Center v. City of New York, 967 F.
2d 764 (2d. Cir. 1992); Citizens for a Better Environment v.
Deukmejian, 731 F. Supp. 1448, reconsideration granted in part, 746
F. Supp. 976 (N.D. Cal. 1990); American Lung Ass'n of New Jersey v.
Keane, 871 F.2d 319 (3d Cir. 1989); NRDC v. New York State
Department of Environmental Conservation, 668 F. Supp. 848 (S.D.N.Y.
1987); Council of Commuter Organizations v. Gorsuch, 683 F.2d 648
(2d Cir. 1982) and Friends of the Earth v. EPA, 499 F.2d. 1118 (2d.
Cir. 1974).
\17\ The Act does require that enhanced I/M programs include
state enforcement through denial of vehicle registration without
proof of compliance with inspection requirements. However, the
enforceable SIP requirement is to develop a program that includes
registration denial, and any enforcement would be against the state
for failing to deny registration. The Act does not contemplate
enforcement actions against individual vehicle owners attempting to
register their vehicles.
---------------------------------------------------------------------------

Comment: A commenter alleges that the public cannot adequately
monitor implementation of the voluntary measures nor determine whether
the emissions reductions are achieved. The commenter admonishes the
State to commit to a solid evaluation or auditing framework to monitor
performance of measures in the VMEP.
Response: Texas is required by its enforceable commitment to
conduct the evaluation and audit mentioned by ED, and should make such
assessments available to the public in the normal course of
administrative practice. The commenters also claim that the state
itself has raised concerns about the emissions reductions that will be
achieved from these measures. Such concerns may be valid, nevertheless
Texas has made a commitment to fill any shortfall in emissions, which
both EPA and citizens can enforce under the Act.
Comment: A commenter makes various arguments about the
unacceptability of the voluntary measures program stemming from the
stationary source permitting program under Title V of the Act.
Response: Title V is totally irrelevant to these mobile source
programs. The voluntary measures program Texas has included in the HG
SIP applies only to mobile sources that are not subject to regulation
under the Title V stationary source operating permit program.
Comment: EPA can not alter its past interpretations without
completing notice-and-comment rulemaking.
Response: EPA believes that this action is consistent with its past
interpretations that enforceable state commitments to take future
action are approvable SIP measures. For example, see EPA actions
approving California plans at 62 FR 1150 ( January 8, 1997) and 65 FR
18903 (April 10, 2000). In addition, this action is consistent with the
guidance that EPA issued in 1997 indicating its belief that voluntary
programs could be approved in conjunction with enforceable state
commitments to fill any resultant shortfall.\18\ The individual SIP
approval actions implementing the VMEP guidance constitute the notice-
and-comment rulemaking required to effectuate action under the
guidance. Thus, this SIP rulemaking satisfies both CAA and APA
rulemaking requirements with respect to final interpretations of the
Act consistent with the guidance. Further, NRDC alleges that EPA may
not alter interpretations of the Administrator through SIP rulemaking
signed by the Regional Administrator. However, the Administrator has
properly delegated the authority for SIP rulemakings to the Regional
Administrators under Delegation 7-10 dated May 6, 1997, and section
301(a)(1) of the Act. Thus, the Regional Administrators are authorized
to act for the Administrator with respect to all matters pertaining to
SIP approvals, including interpretations of the Act relevant to a given
SIP approval.
---------------------------------------------------------------------------

\18\ Guidance on Incorporating Voluntary Mobile Source Emission
Reduction programs in State Implementation Plans (SIPs), October 24,
1997.
---------------------------------------------------------------------------

Comment: A commenter questions the 3% limit on voluntary measures,
arguing that this limit itself implicitly acknowledges that such
measures are not approvable.
Response: EPA did not impose the 3% limit because it believed the
measures to be suspect, but rather, as noted in the VMEP guidance,
based on the innovative nature of the measures and the agency's lack of
experience both

[[Page 57192]]

with implementation and calculating appropriate credit for such
measures. Therefore, EPA created the 3% limit as a policy matter,
indicating in the guidance that it did not think it would be
appropriate to approve a greater percentage while the agency begins to
implement the program. EPA further indicated that it would reassess the
limit after several years of experience with the program. Since all
VMEP measures would be approved only with enforceable state commitments
to fill any resultant shortfall, EPA felt confident that including
voluntary programs up to 3% of required emissions reductions in SIPs
would not jeopardize attainment and maintenance goals during initial
implementation under the policy. Further, EPA did not indicate that 3%
of required emissions reductions could be considered de minimis, as the
commenter implies. EPA agrees with the commenter that it should not
conclude in advance that any given percentage of emissions reduction
could be considered per se de minimis for all areas and types of SIPs.
Any conclusion about the de minimis nature of required emission
reductions should be made in light of the specific circumstances of the
areas and CAA requirements at issue. Therefore, all of the commenter's
arguments relating to the availability of a de minimis exemption and
the need for notice-and-comment rulemaking to effectuate it are not
relevant to EPA's approval of the voluntary measures in the HG area
SIP.
Comment: The record is insufficient to support TNRCC's credit
claims.
Response: EPA reviewed the documentation submitted for each measure
of the VMEP. We found that for each measure the documentation was
acceptable to demonstrate that the criteria for approval were met for
each measure. For each measure the State was able to show that the
measure plus the State commitment was quantifiable, surplus,
enforceable, permanent, and adequately supported.
Comment: One commenter pointed out that delays may result from
identifying and rectifying emissions shortfalls.
Response: EPA acknowledges that reductions will be somewhat delayed
where states must first monitor and assess implementation and
subsequently implement corrections. For this reason EPA indicated in
the VMEP guidance that states should fill any shortfalls in a timely
fashion. EPA recently issued a companion voluntary measures policy for
stationary sources. See, ``Incorporating Voluntary Stationary Source
Emission Reduction Programs Into State Implementation Plans--FINAL
POLICY,'' memorandum and attachment dated website January 19, 2001,
from John Seitz, Director of the Office of Air Quality Planning and
Standards. In that policy EPA indicated that where voluntary measures
were included in attainment or rate of progress SIPs, any shortfalls
would have to be filled prior to the relevant attainment or progress
milestone date. EPA believes this is an appropriate interpretation of
the requirement to fill shortfalls in a timely fashion under the VMEP
policy.
Comment: EPA put forth different, conflicting explanations for why
VMEP measures purportedly will meet the enforceability requirements of
section 110(a)(2) of the Act. In the DFW proposed approval we say that
the measures will be enforced by the State, whereas in the HGA proposed
approval we say that the voluntary measures will be enforceable against
the State.
Response: As discussed above, courts have upheld the legal
authority to enforce state SIP commitments. The language in the DFW
notice was intended to indicate that Texas was to monitor and assess
reductions attributable to VMEP and, in case of a shortfall, implement
measures to offset that shortfall. What is enforceable is the
commitment to see that reductions in an amount equal to what is
proposed in the VMEP are achieved. Such enforcement is also available
against the State, but not against the individual entities that are
implementing the voluntary measures. Texas has made similar commitments
with respect to both Dallas/Fort Worth and the HG area.
Comment: EPA improperly redefined the subject of the enforceability
requirements of section 110(a)(2); that what is enforceable against the
State is the commitment to monitor, assess, and timely remedy a
shortfall from implementation of the measures.
Response: We agree that what is enforceable against the State is
the commitment to monitor, assess and timely remedy any shortfall to
ensure the claimed VMEP reductions are met. We do not agree that this
is improper under the Act and have already cited case law in support of
this position.
Comment: One commenter appreciated EPA's approval of the VMEP and
asked for the State's and EPA's continued support.
Response: We appreciate the commenters support. EPA will continue
to support the State's VMEP activities as long as they are developed
and implemented in accordance with EPA's October 24, 1997, Guidance on
Incorporating Voluntary Mobile Source Emission Reduction Programs in
State Implementation Plans (SIPs) and the responses to comments in this
rulemaking.
3. Comments on TCMs
Comment: The commenters stated that the TCMs are inadequate and do
not satisfy the requirements of section 182(d)(1)(A) of the Act.
Response: Section 182(d)(1)(A) directs the State to submit a SIP
revision that identifies and adopts specific enforceable transportation
control strategies and TCMs to offset any growth in emissions from
growth in vehicle miles traveled or number of vehicle trips in severe
nonattainment areas, and to attain reduction in motor vehicle emissions
as necessary to meet reasonable further progress and attainment
requirements of the Act. The State submitted SIP revisions to the EPA
on August 25, 1997 and May 17, 2000 to address the VMT Offset
provision, the first required element under section 182(d)(1)(A). The
EPA proposed approval of these SIP revisions on July 10, 2001 (66 FR
35920, see also 66 FR 35903), and subsequently received public
comments. The EPA's final approval action on this SIP, the VMT Offset
Plan, has been taken in a separate concurrent Federal Register action
that discusses the emissions growth offset element in detail.
That action also explains that EPA believes it is appropriate to
allow States to separate the VMT Offset SIP into three elements, each
to be submitted at different times: (1) The initial requirement to
submit TCMs that offset growth in emissions; (2) the requirement to
comply within the 15 percent periodic reduction requirement of the Act;
and (3) the requirement to comply with the post-1996 periodic reduction
and attainment requirements of the Act. Please see the concurrent VMT
Offset action referenced above for the first element.
Today's action here satisfies the second and third elements of
section 182(d)(1)(A). EPA believes this SIP action, including its TCMs,
demonstrates that the HG area will achieve the required ROP and
attainment of the ozone NAAQS for the reasons discussed in more detail
throughout this final action, and that the SIP therefore satisfies the
last two elements.

D. Response to Comments on Post 1999 Rate of Progress Plans

Comment: Texas provided a comment on EPA's December 1999 proposal
indicating the April 2000 SIP revision will contain a commitment by the
state

[[Page 57193]]

to submit a full Post-99 ROP analysis by 12/31/00.
Response: Texas has fulfilled this commitment. EPA is approving
this Post-99 ROP plan in this action.
Comment: The TNRCC ROP plan should be revised to be consistent with
the budget. The required NO_X reduction for 2005-2007 should
be more than the 6% (3%/year for the 2 year period) figure included in
Chapter 5.
Response: The EPA acknowledges that the TNRCC has included a 2007
MVEB, which in conjunction with the other measures in the plan will
result in more than 6% emission reduction. The Rate of Progress
requirement is to achieve at a minimum 6% emission reduction for the
time period 2006-2007 as called for by section 182(b)(2) of the Act.
The requirement should remain 6%, setting the MVEB lower will only
result in more reductions than needed to achieve the required ROP
levels.
Comment: One commenter on the December 1999 proposed approval/
proposed disapproval claims that the plans fail to demonstrate emission
reductions of 3% per year over each 3-year period between November 1999
and November 2002; and November 2002 and November 2005; and the 2-year
period between November 2005 and November 2007, as required by 42
U.S.C. section 7511a(c)(2)(B). The states have not even attempted to
demonstrate compliance with these requirements, and EPA has not
proposed to find that they have been met. The EPA has absolutely no
authority to waive the statutory mandate for 3% annual reductions. The
statute does not allow EPA to use the NO_X SIP call or 126
orders as an excuse for waiving rate-of-progress (ROP) deadlines. The
statutory ROP requirement is for emission reductions--not ambient
reductions. Emission reductions in upwind states do not waive the
statutory requirement for 3% annual emission reductions within the
downwind nonattainment area.
Response: Under no condition is EPA waiving the statutory
requirement for 3% annual emission reductions. In today's action we are
approving Texas Post-99 ROP plan as submitted December 2000 and revised
and submitted in October 2001. As provided in this EPA's final action
on the ROP plan Texas is relying on reductions of NO_X and
VOC within the nonattainment area for meeting the ROP requirement.

E. Response to Comments on Administrative Record

Comment: A commenter could not find support in the administrative
record for the following propositions:
The Shortfall
Proposition: Identified potential measures can achieve an
additional 56 tons/day NO_X emissions reduction without
requiring additional limits on highway construction.
Support: In Chapter 7, Texas projected that the measures being
considered for adoption would address the 56 tpd short fall.
Examination of these measures reveals that their implementation would
not result in additional limitations on highway construction. Further,
the State has provided a commitment that future measures will not rely
on limits on highway construction.
Proposition: The State's cited ranges of potential reductions from
measures being considered to address the shortfall provide a
``reasonable assurance'' that the State can meet its commitment to
submit adopted measures to fill the shortfall; the State has identified
sufficient innovative programs and new technologies such that it is
reasonable to believe that, in the aggregate, the projected emission
reductions from these new programs and technologies can be achieved and
will fill the shortfall and the measures to be considered for adoption
at the mid-course review can achieve the NO_X emissions
reductions indicated on pp. 23-24 of the Technical Support Document.
Support: Chapter 7 of the Texas SIP discusses each of the measures
and the State's projected range of emission reductions. The TSD in
Section IV.F. has further discussion of each of the potential measures
and information that exists to support the projected emission
reductions.
SB5 and Incentive Programs
Proposition: Texas Emission Reduction Plan (TERP) will provide 130
million dollars per year for incentive programs to reduce emissions.
Support: This estimate was based on fiscal estimates provided by
the State regarding the revenue that will be available from the fees
associated with this bill. Chapter 7 of the adopted SIP cites an
estimate of 133 million dollars.
Proposition: Incentive programs in SB5 can achieve more reductions
than the reductions that were projected to be achieved by the
accelerated purchase of Tier II/III non-road diesel equipment and the
Heavy-duty Diesel Equipment Operating Restrictions measure and can
contribute to reducing the shortfall.
Support: This is discussed at Section IV.F. of the TSD.
Proposition: It can safely be assumed that at least 45% of the SB5
funding for clean up of diesel engines will go to the HG area and TERP
can reasonably be expected to provide 40 million dollars/year to the HG
area for reducing emissions from existing diesel equipment.
Support: These assumptions were first developed based on early
discussions with TNRCC. We understand as pointed out by the commenter
that only $24.7 million/year are currently being planned for the HG
area. As discussed in our response to comment on this issue, we believe
this will still provide sufficient funds to replace the emission
reductions from the morning construction ban and Accelerated Tier II/
III. clearly, the priority of TNRCC and the legislation is to preserve
the HG and Dallas/Fort Worth SIPs. to that end as discussed in the
comments on this control strategy in section III.B.3, Texas has the
discretion to provide more money, even more than 40 million, to the HG
area if necessary.
Proposition: Incentive programs in SB5 can obtain emissions
reductions from existing diesel equipment at an average cost on the
order of $3,000-5,000/ton.
Support: As stated in the TSD, this is based on experience with
California programs. The actual experience of the Carl Moyer Program is
a cost effectiveness of better than $3000/ton as stated in ``The Carl
Moyer Memorial Air Quality Standards Attainment Program (The Carl Moyer
Program) Guidelines-Approved Revision 2000, November 16, 2000
California Environmental Protection Agency Air Resources Board.''
Proposition: The TERP program for reducing emissions from diesel
equipment can achieve between 32 and 40 tons/day of emissions
reductions in the HG area.
Support: This is discussed in IV.F of the TSD. It is also discussed
in Chapter 7 of the adopted version of the Texas SIP and in the
responses to comments in this action.
Proposition: The TERP's projected emissions reductions that will be
substituted for the Tier II/III non-road diesel equipment measure will
achieve 12.2 tons/day. It is also discussed in Chapter 7 of the adopted
version of the Texas SIP submitted in a letter dated October 4, 2001.
Support: This is discussed in Section IV.F of the TSD.
Growth Rates
Proposition: Projected growth rates and emissions reductions from
the sources subject to the Tier 2 Vehicle Emission Standards and
Federal Low Sulfur Gasoline, National Low Emitting

[[Page 57194]]

Vehicle Standards, and Heavy-duty Diesel Standards were calculated
correctly by the State.
Support: The procedures for calculating the emissions from on-road
vehicles are documented in Chapter 3 of the SIP. As discussed in
Chapter 3, these emissions are based on a report that was included in
Appendix G of the November 1999 SIP revision. Chapter 3 discusses
several refinements and revisions to what was provided in the November
1999 SIP. These were discussed in Appendix A of the TSD Section I.F.
Proposition: Growth rates and emission reductions were correctly
projected by the State for sources subject to the Federal Measures,
including on-road and off-road mobile source measures and the Act
Statutory Requirements.
Support: On-road measures were discussed in the previous
proposition. Off-road measures are also discussed in I.F. of Appendix A
of the TSD.
Proposition: The State has correctly factored growth in emissions
due to population and economic growth.
Support: These are discussed in Section I.G.4 of Appendix A of the
TSD.
Settlement
Proposition: Additional controls at uncontrolled grandfathered
facilities in East Texas, which are called for by recent legislation,
will offset the increased emissions from utilities pursuant to the
settlement agreement.
Support: This issue is discussed in Chapter 6 of the Texas SIP.
EPA's review is discussed in the TSD in Section III.K of the TSD. The
issue is also discussed in the response to comments regarding model
inputs.
Proposition: Substitution of a portion of the emissions reductions
from the new TERP measures for the modeled Heavy-duty Diesel Equipment
Operating Restrictions along with the change in the NO_X
point source measures are not expected to increase the modeled ozone
reductions. Changes in the Heavy-duty Diesel Equipment Operating
Restrictions and rules for utilities will not ``adversely affect the
modeling results'' or ``affect modeling results in a way to increase
ozone.''
Support: These issues were discussed in III. I. of the TSD and in
Chapter 7 of the adopted SIP revision.
Speed Limit Reductions
Proposition: Reductions in the speed limit to 55 mph in the HG area
will result in the reductions calculated by TTI. The percentage of
motorists that TTI projected to exceed the newly proposed speed limits
is reasonable.
Support: The reduction in speed limit is discussed in detail in
TNRCC's SIP and in particular in the State's response to comments in
the December 2000 SIP. EPA reviewed and evaluated these documents to
draw these conclusions. Also, se the Chapter 3 of the December 2000 SIP
and Appendix A of the TSD.

RACM

Proposition: Texas has established that all reasonable measures
that could accelerate the attainment date have been adopted, or will be
adopted.
Support: Chapter 7 of the SIP and Appendix B of the TSD extensively
discuss this issue.

VOCs

Proposition: The modeling and list of control measures demonstrate
that additional VOC controls are not cost-effective in reducing ozone
in the HG area and would not advance the attainment deadline.
Support: This issue is extensively discussed in Appendix B. of the
TSD and Chapter 7 of the SIP. This issue is discussed further in our
response to comments on this action.
Proposition: RACT is in place for all major sources of VOC in the
HG area.
Support: As part of our action approving VOC requirements, we found
that the State had adopted RACT for all major sources, in the HG area
except those that were to be covered by post-enactment Control
Technique Guidelines (CTG's)(60 FR 12437, March 7, 1995). Since that
time many expected CTGs were issued as Alternative Control Technique
documents--ACTs. Of the expected CTGs and ACTs, the HG area had major
sources in the following categories; batch processing, industrial
wastewater, reactors and distillation, and wood furniture. We have
approved measures for all of these categories as meeting RACT.

Batch Processing--July 16, 2001 66 FR 36913
Industrial Wastewater--December 10, 2000 65 FR 79745
Reactors and Distillation--January 26, 1999, 64 FR 3841
Wood Furniture--October 30, 1996, 61 FR 55894
State's Estimated NO_X Reductions
Proposition: The State control measures and local initiatives will
provide the NO_X reductions indicated in Table 4 of the TSD.
The State's projection of expected emissions reductions from Regional
and Local Measures is correct (this includes the adequacy of the
equivalent NO_X reductions credited to the commercial lawn
care shift). The NO_X reductions for the 2007 attainment year
resulting from the State control measures and local initiatives
predicted in Table 4 on pg. 18 of the TSD are accurate.
Support: First, each of the control measures have been approved in
separate actions or in this action as listed in Section II of this
action. These Federal Register actions announce our belief that these
are permanent, enforceable measures that will achieve emission
reductions toward attainment. Regarding the projected emission
reductions from each measure:
Point Source Control reductions are well documented in a table in
the State's preamble to NO_X rules submitted in December
2000. We reviewed this table in concluding the SIP will achieve the
projected reductions from point sources. Also see the EPA's TSDs for
its actions on the point source rule and this action.
The record for reductions for on-road emissions reductions from I/
M, low emissions diesel fuel, speed limit reductions, and vehicle
idling are discussed in previous propositions. They are principally
discussed in the record in Chapter 3 of the SIP and in Appendix A of
the TSD.
Off-road measures; Heavy duty diesel operating restriction and
Accelerated Tier II/III have been replaced by the TERP and the
potential emission reductions from the TERP are discussed in section
IV.F. of the TSD. The emissions shifted by small spark operating
restrictions are discussed in the State's preamble to the rule and in
Chapter 6. Airport GSE emissions are discussed in Appendix A of the
TNRCC December 2000 SIP submission, Heavy equipment gas engines
emission reductions are discussed in the State's preamble to the rules
submitted in December 2000.
Gas-fired water heaters--EPA reviewed the discussion provided in
the State's preamble to the water heater and small boiler rule.
VMEP measures and the projected emission reductions are extensively
discussed in Appendix K of the December 2000 State submission and in
section IV of the TSD.
Energy Efficiency projections are discussed in Chapter 6 of the
SIP.
Transportation Control Measure are documented in Appendix I of the
SIP and discussed in section IV of the TSD.

IV. Administrative Requirements

Under Executive Order 12866 (58 FR 51735, October 4, 1993), this
action is not a ``significant regulatory action'' and therefore is not
subject to review by the Office of Management and Budget. For this
reason, this action is also not

[[Page 57195]]

subject to Executive Order 13211, ``Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use'' (66 FR
28355, May 22, 2001). This action merely approves state law as meeting
Federal requirements and imposes no additional requirements beyond
those imposed by state law. Accordingly, the Administrator certifies
that this rule will not have a significant economic impact on a
substantial number of small entities under the Regulatory Flexibility
Act (5 U.S.C. 601 et seq.). Because this rule approves pre-existing
requirements under state law and does not impose any additional
enforceable duty beyond that required by state law, it does not contain
any unfunded mandate or significantly or uniquely affect small
governments, as described in the Unfunded Mandates Reform Act of 1995
(Pub. L. 104-4).
This rule also does not have tribal implications because it will
not have a substantial direct effect on one or more Indian tribes, on
the relationship between the Federal Government and Indian tribes, or
on the distribution of power and responsibilities between the Federal
Government and Indian tribes, as specified by Executive Order 13175 (65
FR 67249, November 9, 2000). This action also does not have Federalism
implications because it does not have substantial direct effects on the
States, on the relationship between the national government and the
States, or on the distribution of power and responsibilities among the
various levels of government, as specified in Executive Order 13132 (64
FR 43255, August 10, 1999). This action merely approves a state rule
implementing a Federal standard, and does not alter the relationship or
the distribution of power and responsibilities established in the Act.
This rule also is not subject to Executive Order 13045 ``Protection of
Children from Environmental Health Risks and Safety Risks'' (62 FR
19885, April 23, 1997), because it is not economically significant.
In reviewing SIP submissions, EPA's role is to approve state
choices, provided that they meet the criteria of the Act. In this
context, in the absence of a prior existing requirement for the State
to use voluntary consensus standards (VCS), EPA has no authority to
disapprove a SIP submission for failure to use VCS. It would thus be
inconsistent with applicable law for EPA, when it reviews a SIP
submission, to use VCS in place of a SIP submission that otherwise
satisfies the provisions of the Act. Thus, the requirements of section
12(d) of the National Technology Transfer and Advancement Act of 1995
(15 U.S.C. 272 note) do not apply. This rule does not impose an
information collection burden under the provisions of the Paperwork
Reduction Act of 1995 (44 U.S.C. 3501 et seq.).
The Congressional Review Act, 5 U.S.C. section 801 et seq., as
added by the Small Business Regulatory Enforcement Fairness Act of
1996, generally provides that before a rule may take effect, the agency
promulgating the rule must submit a rule report, which includes a copy
of the rule, to each House of the Congress and to the Comptroller
General of the United States. EPA will submit a report containing this
rule and other required information to the U.S. Senate, the U.S. House
of Representatives, and the Comptroller General of the United States
prior to publication of the rule in the Federal Register. A major rule
cannot take effect until 60 days after it is published in the Federal
Register. This action is not a ``major rule'' as defined by 5 U.S.C.
section 804(2).
Under section 307(b)(1) of the Act, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the appropriate circuit by January 14, 2002. Filing a petition for
reconsideration by the Administrator of this final rule does not affect
the finality of this rule for the purposes of judicial review nor does
it extend the time within which a petition for judicial review may be
filed, and shall not postpone the effectiveness of such rule or action.
This action may not be challenged later in proceedings to enforce its
requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, Attainment,
Hydrocarbons, Nitrogen oxides, Ozone, Incorporation by reference,
Reporting and recordkeeping requirements.

Dated: October 15, 2001
Gregg A. Cooke,
Regional Administrator, Region 6.

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 et seq.

Subpart SS--Texas

2. In Sec. 52.2270, entries in the ``EPA Approved Nonregulatory
Provisions and Quasi-Regulatory Measures in the Texas SIP'' table in
paragraph (e) are added to the end of the table to read as follows:

Sec. 52.2270 Identification of plan.

* * * * *
(e) * * *

EPA Approved Nonregulatory Provisions and Quasi-Regulatory Measures in the Texas SIP
----------------------------------------------------------------------------------------------------------------
State
Applicable submittal/
Name of SIP provision geographic or effective EPA approval date Comments
nonattainment area date
----------------------------------------------------------------------------------------------------------------

* * * * * *
*
----------------------------------------------------------------------------------------------------------------
Attainment Demonstration for the Houston/Galveston, \1\ 12/09/ [Insert 11/14/01
1-hour Ozone NAAQS. TX. 00 Federal Register
cite].
Speed Limit Reduction........... Houston/Galveston, 12/09/00 [Insert 11/14/01 Section 6.3.12
TX. Federal Register
cite].
Voluntary Mobile Emission Houston/Galveston, 12/09/00 [Insert 11/14/01
Program. TX. Federal Register
cite].
Texas Senate Bill 5............. Houston/Galveston, 9/26/00 [Insert 11/14/01
TX. Federal Register
cite].
Transportation Control Measures Houston/Galveston, 12/09/00 [Insert 11/14/01
Appendix I. TX. Federal Register
cite].
Commitment to Mid-course review. Houston/Galveston, 4/19/01 [Insert 11/14/01
TX. Federal Register
cite].

[[Page 57196]]

Table 7.1-1 Enforceable Houston/Galveston, 9/26/01 [Insert 11/14/01
Commitments. TX. Federal Register
cite].
Post 1999 Rate of Progress Plans Houston/Galveston, 9/26/01 [Insert 11/14/01
and associated contingency TX. Federal Register
measures. cite].
15% Rate of Progress Plan....... Houston/Galveston, 12/09/00 [Insert 11/14/01
TX. Federal Register
cite].
Revisions to the 1990 Base Year Houston/Galveston, 12/09/00 [Insert 11/14/01
Inventory. TX. Federal Register
cite].
Reasonably Available Control Houston/Galveston, 9/26/01 [Insert 11/14/01
Measure Analysis. TX. Federal Register
cite].
----------------------------------------------------------------------------------------------------------------
\1\ As revised 9/26/01.

* * * * *
[FR Doc. 01-27580 Filed 11-13-01; 8:45 am]
BILLING CODE 6560-50-P

Notices For
2009
2008
2007
2006
2005
2004
2003
2002
2001
2000
1999
1998
1997
1996
1995
1994

Approval and Promulgation of Implementation Plans; Texas; Houston/Galveston Nonattainment Area; Ozone

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