[Federal Register Volume 66, Number 220 (Wednesday, November 14, 2001)]
[Rules and Regulations]
[Pages 57160-57196]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-27580]



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Part II





Environmental Protection Agency





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40 CFR Part 52



Approval and Promulgation of Air Quality State Implementation Plans 
(SIP); Texas (8 Documents); Final Rules

  Federal Register / Vol. 66 , No. 220 / Wednesday, November 14, 2001 / 
Rules and Regulations  

[[Page 57160]]


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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: [email protected].

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

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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 NOX 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 NOX 
reductions.
     An enforceable commitment that the rules needed for the 
additional NOX 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
NOX.........................................   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
NOX..........................................................     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

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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 NOX 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 NOX 
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.--NOX 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.              NOX Point Source         NOX 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 
NOX Point Sources (30 TAC 117). Final approval published 
separately in this issue of the Federal Register.
    3. NOX 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

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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, NOX emissions are a precursor 
to particulate matter formation. So the large NOX emissions 
reductions in the plan should provide improvements in particulate 
matter levels. In addition, while the focus of the plan is on reducing 
NOX 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 NOX 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 NOX control 
strategies, EPA was cautioning TNRCC that sufficient NOX 
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 NOX 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 
NOX 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 NOX 
emission reductions needed for attainment. Furthermore, even if the 
model is shown during the mid-course review to be overestimating the 
amount of NOX 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 
NOX 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 NOX, 
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 NOX 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 NOX, 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 
NOX 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 NOX 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 
NOX 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 NOX 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 
NOX 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 NOX 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 NOX 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 
NOX 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 NOX 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 NOX reductions at reducing ozone levels (given 
the ratio of mobile source to point source NOX 
effectiveness). From this, it follows that mobile source NOX 
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 NOX plume generates ozone and is an indication of 
the reactivity of the VOCs with which the NOX 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 NOX 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 
NOX 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 NOX 
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://www.nescaum.org/pdf/pubslist.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 NOX 
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 NOX. 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://www.nescaum.org/pdf/pubslist.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 NOX 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 NOX mobile vehicle 
emissions budget is based, Texas modeled NOX 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 NOX 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 NOX is a 71% reduction from the projected 2007 
NOX emissions of 1052 t/d and a 77% reduction from the 1993 
NOX emissions of 1337 t/d. This is a significant amount of 
NOX 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% NOX 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 NOX 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 NOX 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 NOX 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 NOX 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 NOX 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 NOX reductions. 
However, it appears that the NOX 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.
---------------------------------------------------------------------------

    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, NOX 
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.
---------------------------------------------------------------------------

    \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 NOX 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 NOX 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 NOX source category. 
The SIP for the HG area already includes NOX 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 NOX 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 NOX 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 NOX 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 NOX, 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 NOX 
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 NOX 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.
---------------------------------------------------------------------------

    \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 NOX 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 NOX SIP call, Texas is not included in the mandatory 
NOX SIP call. However, it should also be noted that even 
though Texas was not included, Texas adopted control measures for 
regional NOX 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 
NOX 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 NOX 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 NOX 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 ( NOX). 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 NOX emission 
reductions are much more effective in reducing ozone and thus, 
NOX 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 NOX 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 NOX 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 NOX controls called for in 
the plan including the 56 tons/day NOX 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 NOX 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 NOX 
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 NOX 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/title6/snap/).

[[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 NOX Controls

    Comment: The Phase II NOX 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 
NOX RACT limits for all relevant facilities. It is not 
sufficient for States to assert that they will adopt additional 
NOX controls if needed.
    Response: That the OTC states have implemented the OTC Phase II 
NOX 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 NOX 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 
NOX 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 
NOX 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 NOX 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 NOX 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 NOX 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 
NOX 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 
(NOX) 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 NOX 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 NOX 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 NOX 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 NOX 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 NOX 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 NOX 
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 NOX 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 NOX 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 NOX 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 NOX 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 NOX 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 NOX 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 NOX 
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 NOX Reductions
    Proposition: The State control measures and local initiatives will 
provide the NOX 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 NOX reductions credited to the commercial lawn 
care shift). The NOX 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 NOX 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