[Federal Register Volume 73, Number 135 (Monday, July 14, 2008)]
[Proposed Rules]
[Pages 40203-40228]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E8-15805]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2007-0524; FRL-8690-7]


Approval and Promulgation of Air Quality Implementation Plans; 
Texas; Attainment Demonstration for the Dallas/Fort Worth 1997 8-Hour 
Ozone Nonattainment Area

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: EPA is proposing to conditionally approve the 1997 8-hour 
ozone attainment demonstration State Implementation Plan (SIP) revision 
for the Dallas/Fort Worth moderate 8-hour ozone nonattainment area (DFW 
area) submitted by the State of Texas on May 30, 2007 and supplemented 
on April 23, 2008. We are also proposing to approve the associated 
attainment Motor Vehicle

[[Page 40204]]

Emissions Budgets (MVEBs), the Reasonably Available Control Measures 
(RACM) demonstration, and two local control measures relied upon in the 
attainment demonstration. The proposed approval of the attainment 
demonstration is conditioned on Texas adopting and submitting to EPA 
prior to March 2009, a complete SIP revision to limit the use of 
Discrete Emission Reduction Credits (DERCs), beginning in March 2009. 
Final conditional approval of the DFW 1997 8-hour ozone attainment 
demonstration SIP is contingent upon Texas adopting and submitting to 
EPA an approvable SIP revision for the attainment demonstration SIP's 
failure-to-attain contingency measures plan that meets section 
172(c)(9) of the Clean Air Act (the Act).
    We also are proposing to fully approve the DFW area SIP as meeting 
the Reasonably Available Control Technology (RACT) requirement for 
volatile organic compounds (VOCs). EPA is proposing these actions in 
accordance with section 110 and part D of the Act and EPA's 
regulations.

DATES: Comments must be received on or before August 13, 2008.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R06-
OAR-2007-0524, by one of the following methods:
     Federal Rulemaking Portal: http://www.regulations.gov. 
Follow the on-line instructions for submitting comments.
     U.S. EPA Region 6 ``Contact Us'' Web site: http://epa.gov/region6/r6coment.htm. Please click on ``6PD'' (Multimedia) and select 
``Air'' before submitting comments.
     E-mail: Mr. Guy Donaldson at [email protected]. Please 
also send a copy by email to the person listed in the FOR FURTHER 
INFORMATION CONTACT section below.
     Fax: Mr. Guy Donaldson, Chief, Air Planning Section (6PD-
L), at fax number 214-665-7263.
     Mail: Mr. Guy Donaldson, Chief, Air Planning Section (6PD-
L), Environmental Protection Agency, 1445 Ross Avenue, Suite 1200, 
Dallas, Texas 75202-2733.
     Hand or Courier Delivery: Mr. Guy Donaldson, Chief, Air 
Planning Section (6PD-L), Environmental Protection Agency, 1445 Ross 
Avenue, Suite 1200, Dallas, Texas 75202-2733. Such deliveries are 
accepted only between the hours of 8 a.m. and 4 p.m. weekdays except 
for legal holidays. Special arrangements should be made for deliveries 
of boxed information.
    Instructions: Direct your comments to Docket ID No. EPA-R06-OAR-
2007-0524. EPA's policy is that all comments received will be included 
in the public docket without change and may be made available online at 
http://www.regulations.gov, including any personal information 
provided, unless the comment includes information claimed to be 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute. Do not submit through http://www.regulations.gov or e-mail, information that you consider to be CBI 
or otherwise protected. The http://www.regulations.gov Web site is an 
``anonymous access'' system, which means EPA will not know your 
identity or contact information unless you provide it in the body of 
your comment. If you send an e-mail comment directly to EPA without 
going through http://www.regulations.gov, your e-mail address will be 
automatically captured and included as part of the comment that is 
placed in the public docket and made available on the Internet. If you 
submit an electronic comment, EPA recommends that you include your name 
and other contact information in the body of your comment and with any 
disk or CD-ROM you submit. If EPA cannot read your comment due to 
technical difficulties and cannot contact you for clarification, EPA 
may not be able to consider your comment. Electronic files should avoid 
the use of special characters, any form of encryption, and be free of 
any defects or viruses. For additional information about EPA's public 
docket visit the EPA Docket Center homepage at http://www.epa.gov/epahome/dockets.htm.
    Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some 
information is not publicly available, e.g., CBI or other information 
whose disclosure is restricted by statute. Certain other material, such 
as copyrighted material, will be publicly available only in hard copy. 
Publicly available docket materials are available either electronically 
in http://www.regulations.gov or in hard copy at the Air Planning 
Section (6PD-L), Environmental Protection Agency, 1445 Ross Avenue, 
Suite 700, Dallas, Texas 75202-2733. The file will be made available by 
appointment for public inspection in the Region 6 FOIA Review Room 
between the hours of 8:30 a.m. and 4:30 p.m. weekdays except for legal 
holidays. Contact the person listed in the FOR FURTHER INFORMATION 
CONTACT paragraph below to make an appointment. If possible, please 
make the appointment at least two working days in advance of your 
visit. There will be a fee of 15 cents per page for making photocopies 
of documents. On the day of the visit, please check in at the EPA 
Region 6 reception area at 1445 Ross Avenue, Suite 700, Dallas, Texas.
    The State submittal, which is part of the EPA record, is also 
available for public inspection at the State Air Agency listed below 
during official business hours by appointment: Texas Commission on 
Environmental Quality, Office of Air Quality, 12124 Park 35 Circle, 
Austin, Texas 78753.

FOR FURTHER INFORMATION CONTACT: Ms. Carrie Paige, Air Planning Section 
(6PD-L), Environmental Protection Agency, Region 6, 1445 Ross Avenue, 
Suite 700, Dallas, Texas 75202-2733, telephone (214) 665-6521; fax 
number 214-665-7263; e-mail address [email protected].

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

Table of Contents

I. What Has the State Submitted?
II. What Action Is EPA Proposing?
    A. What Must Happen Before We Can Finalize Conditional Approval?
III. Why Is This Proposed Approval Conditional and What Are the 
Implications of a Conditional Approval?
IV. Background.
    A. What Are the National Ambient Air Quality Standards?
    B. What Is a SIP?
    C. What Is Ozone and Why Do We Regulate It?
    D. Background of the Texas SIP for the DFW Area.
    E. Background of This SIP Revision To Address the 1997 Ozone 
NAAQS.
    F. What Is an Attainment Demonstration?
V. Evaluation of the DFW 1997 8-Hour Ozone Attainment Demonstration 
SIP.
    A. Legal Requirements for Approval
    B. Eight-Hour Attainment Demonstration Modeling and Weight of 
Evidence.
    a. What Were the Results of the Photochemical Modeling 
Attainment Demonstration?
    i. What Is a Photochemical Grid Model?
    ii. What Episode Did Texas Choose to Model?
    iii. How Well Did the Model Perform?
    iv. Once the Base Case Is Determined To Be Acceptable, How Do 
You Use the Modeling for the Attainment Demonstration?
    v. What Modeling Approaches Were Used for This Attainment 
Demonstration?
    vi. What Did the Results of TCEQ's Combo 10 Modeling Show?
    vii. Evaluation of Other Modeling Projections Without Benefit of 
Measures With a 2010 Compliance Date
    viii. Refinements and Adjustments to Future Year (2009) Emission 
Inventory and Modeling-Based Projected Changes to the SIP Modeling 
FDVs
    ix. What are EPA's Conclusions of the Modeling Demonstration?

[[Page 40205]]

    b. What Weight of Evidence Has Been Evaluated?
    i. What Additional Modeling-Based Evidence Did Texas Provide?
    1. Texas Emission Reduction Plan
    2. Compressor Engines
    ii. Other Non-Modeling WOE From TCEQ
    iii. EPA WOE Analysis
    1. EPA Meteorological Adjusted Trends Analysis
    iv. Other WOE Items From Texas Not Currently Quantified: 
Additional Programs/Reductions
    1. AirCheckTexas
    2. Local Quantified and Unquantified Measures
    c. Is the 8-Hour Attainment Demonstration Approvable?
    C. Control Measures Relied Upon by the State in the Attainment 
Demonstration SIP
    D. Local Measures Relied Upon in the Control Strategy Modeling
    a. Voluntary Mobile Source Emission Reduction Programs
    b. Transportation Control Measures (TCMs)
    c. Measures Discussed in the April 23, 2008 Letter From TCEQ
    i. Texas Emission Reduction Plan (TERP)
    ii. Discrete Emission Credits (DECs)
    E. Reasonably Available Control Measures (RACM)
    F. Failure-To-Attain Contingency Measures
    G. Attainment Motor Vehicle Emission Budgets
    H. Section 110(l) Analysis
VI. Reasonably Available Control Technology (RACT)
VII. Proposed Action
VIII. Statutory and Executive Order Reviews

I. What Has the State Submitted?

    On May 30, 2007, Texas submitted a plan designed to attain the 8-
hour National Ambient Air Quality Standard (NAAQS) for ozone adopted in 
1997 (the 1997 8-hour ozone standard). Texas supplemented this 
submission with additional information in a letter dated April 23, 
2008. The attainment demonstration relies on a variety of controls on 
minor and major stationary sources and controls on mobile source 
emissions. The emissions reductions are achieved through a combination 
of Federal, State and Local measures. These measures are projected to 
reduce emissions of NOX, a precursor to ozone formation, in 
the DFW area by over 50% from 1999 levels. Some of the measures that 
have been relied on in this demonstration are being reviewed in this 
Federal Register (FR). Many are being reviewed or have been reviewed in 
other FR notices. All of the measures that are relied on in the plan 
must be approved before we can finalize our approval. The Texas 
Commission on Environmental Quality (TCEQ) used photochemical modeling 
and other corroborative evidence to predict the improvement in ozone 
levels that will occur due to these controls while taking into account 
the growth in the DFW area.
    The State's submission does not directly address the new ozone 
standard issued March 12, 2008. The new ozone standard is more 
protective and will require further reductions to attain, but the Texas 
plan will provide progress toward this new standard.

II. What Action Is EPA Proposing?

    The EPA is proposing to conditionally approve the 1997 8-hour ozone 
attainment demonstration SIP revision for the DFW area (8-hour DFW SIP) 
submitted on May 30, 2007 and supplemented on April 23, 2008. This 
submittal provides photochemical modeling, corroborative analyses, 
additional control measures not explicitly accounted for in the 
photochemical modeling, and a combination of adopted Federal, State, 
and local measures to demonstrate that the DFW area will attain the 
1997 8-hour ozone standard by June 15, 2010. It also includes, as part 
of the attainment demonstration SIP, an attainment MVEB, a RACM 
analysis, and control measures. In today's action, we are proposing to 
approve two local measures relied upon in the attainment 
demonstration--the Voluntary Mobile Source Emission Reduction Program 
(VMEP) and Transportation Control Measures (TCMs); we are proposing to 
adopt the attainment MVEBs into the DFW SIP; and we are proposing to 
approve the demonstration that all RACM have been adopted for the DFW 
area. Finally, in today's action, EPA also is proposing to fully 
approve the VOC RACT submissions for both the 1-hour and the 1997 8-
hour ozone standards.

A. What Must Happen Before We Can Finalize Conditional Approval?

    Before finalizing conditional approval of the attainment 
demonstration SIP, we must fully approve all of the control measures 
relied on in the attainment demonstration and the Reasonable Further 
Progress (RFP) Plan. In the 8-hour DFW SIP, the State included new 
NOX emissions reductions measures and rules (found in Title 
30 of the Texas Administrative Code, Chapter 117--denoted 30 TAC 117 or 
Chapter 117), a VMEP, and TCMs. The revisions to Chapter 117 include 
NOX reductions from the following sources: Industrial, 
Commercial, and Institutional (ICI) Sources, Minor Sources, Electric 
Generating Facilities (EGFs), Cement Kilns and East Texas Combustion 
Sources. The measures in the 8-hour DFW SIP also include rules that 
were adopted under the 1-hour ozone standard, which have been extended 
to the larger 8-hour ozone nonattainment area (NAA). These previously 
adopted rules were approved in earlier actions and are listed in 
section V-C of today's rulemaking. In separate rulemakings, we are 
proposing to approve the 2007 RFP SIP and the remaining control 
measures including NOX controls submitted on May 30, 2007, 
for point and area sources, which include ICI Sources, EGFs, Minor 
Sources, Cement Kilns and East Texas Combustion Sources. We will also 
take action on other emissions reduction measures submitted on May 13, 
2005, which include the April 9, 2003 Alcoa Federal consent decree, an 
Energy Efficiencies Program and NOX rules.
    A description of all the measures that must be approved by EPA 
before any final approval of the attainment demonstration SIP is in 
section V of today's action.
    In addition, we cannot finalize the proposed conditional approval 
until Texas submits an approvable SIP revision to satisfy the section 
172(c)(9) requirement for contingency measures that would be triggered 
if the area fails to attain the 8-hour ozone standard by its attainment 
date. This SIP revision (the contingency for final conditional 
approval) must be a complete approvable failure-to-attain contingency 
measures plan. Texas has committed to adopt and submit a plan that 
relies upon three VOC SIP rules for Offset Lithographic Printing; 
Degassing or Cleaning of Stationary, Marine and Transport Vessels; and 
Petroleum Dry Cleaning, as well as fleet turnover from mobile sources 
after 2009 as contingency measures. These measures are more fully 
described in a commitment letter submitted by the State, dated June 13, 
2008 (this letter is in the docket for this action). If the State 
submits a complete failure-to-attain contingency measures plan that 
relies upon the four above-noted control measures, EPA could proceed 
with a final conditional approval of the attainment demonstration SIP. 
Any comments concerning whether these four measures are sufficient to 
meet the failure-to-attain contingency measure requirement should be 
raised at this time. EPA does not plan to provide an additional 
opportunity for comment unless the State modifies these measures or 
submits a failure-to-attain contingency measures plan relying on other 
measures.

[[Page 40206]]

III. Why Is This Proposed Approval Conditional and What Are the 
Implications of a Conditional Approval?

    Our proposed approval of the attainment demonstration SIP is 
conditional because the attainment demonstration submitted in May 2007 
relies upon unlimited usage of DERCs, whereas the April 2008 
supplemented attainment demonstration relies upon a limited usage of 
DERCs; as yet there is no State rule implementing this change. The 
condition is based on a commitment by the State of Texas to adopt and 
submit by March 1, 2009, a complete SIP revision that includes an 
enforceable mechanism that would allow no more than 3.2 tons per day 
(tpd) of DERCs to be used in 2009 in the DFW area. If Texas intends to 
allow for more than 3.2 tpd of DERCs to be used beginning January 1, 
2010, then the SIP revision must also provide appropriate limits on the 
use of DERCs and a detailed justification explaining how the future 
adjustments to the allowed DERC usage will be consistent with continued 
attainment of the 8-hour ozone standard. The justification must provide 
sufficient detail such that the public can be assured that attainment 
will continue to be projected in future years. For further explanation 
of the limitation on DERCs, see section V-D.
    Under section 110(k) of the Act, EPA may conditionally approve a 
plan based on a commitment from the State to adopt specific enforceable 
measures within one year from the date of approval. The TCEQ submitted 
a commitment letter to EPA committing to adopt and submit to EPA by 
March 1, 2009, a SIP revision addressing the DERC restrictions for 2009 
and addressing the use of DERCs in subsequent years. This letter, dated 
June 13, 2008, is in the docket for this action.
    If EPA issues a final conditional approval of the SIP before March 
1, 2009 and Texas subsequently fails to adopt and submit the DERC SIP 
revision as committed to in its letter, EPA will issue a letter to the 
State converting the conditional approval of the 1997 8-hour ozone DFW 
attainment demonstration SIP to a disapproval. Such disapproval will 
start the 18-month clock for sanctions in accordance with section 
179(b) and 40 CFR 52.31 and the 2-year clock for a Federal 
Implementation Plan (FIP) under section 110(c). EPA would publish in 
the Federal Register a notice regarding the disapproval of the SIP and 
the start of sanctions and FIP clocks for the DFW area, and would 
revise the provisions in the Code of Federal Regulations (CFR) to 
reflect the disapproval of the SIP.
    The State anticipates the DERC and contingency measure SIP 
revisions to be proposed for public review and comment in Summer 2008, 
and final adoption of the revisions is expected early in 2009 in order 
to meet the commitment to submit the revisions to EPA by March 1, 2009. 
If EPA finds that the submitted DERC SIP rule is approvable, we will 
propose approval of the rule and could proceed with final full approval 
of the attainment demonstration. Final conditional approval of the 
attainment demonstration SIP would remain in effect until EPA takes 
final action to convert the conditional approval to a full approval or 
disapproval of the attainment demonstration. If EPA cannot fully 
approve the revision concerning the use of DERCs in the DFW area, EPA 
will propose disapproval of the submitted SIP rule and the attainment 
demonstration SIP for the DFW area. The 18-month clock for sanctions 
and the 2-year clock for a FIP start on the date of final disapproval.

IV. Background

A. What Are the National Ambient Air Quality Standards?

    Section 109 of the Act requires EPA to establish National Ambient 
Air Quality Standards (NAAQS or standards) for pollutants that ``may 
reasonably be anticipated to endanger public health and welfare,'' and 
to develop a primary and secondary standard for each NAAQS. The primary 
standard is designed to protect human health with an adequate margin of 
safety, and the secondary standard is designed to protect public 
welfare and the environment. EPA has set NAAQS for six common air 
pollutants, referred to as criteria pollutants: carbon monoxide, lead, 
nitrogen dioxide, ozone, particulate matter, and sulfur dioxide. These 
standards present State and local governments with the minimum air 
quality levels they must meet to comply with the Act. Also, these 
standards provide information to residents of the United States about 
the air quality in their communities.

B. What Is a SIP?

    The SIP is a set of air pollution regulations, control strategies, 
other means or techniques, and technical analyses developed by the 
State, to ensure that the State meets the NAAQS. The SIP is required by 
section 110 and other provisions of the Act. These SIPs can be 
extensive, containing State regulations or other enforceable documents 
and supporting information such as emissions inventories, monitoring 
networks, and modeling demonstrations. Each State must submit these 
regulations and control strategies to EPA for approval and 
incorporation into the federally-enforceable SIP. Each Federally-
approved SIP protects air quality primarily by addressing air pollution 
at its point of origin.

C. What Is Ozone and Why Do We Regulate It?

    Ozone is a gas composed of three oxygen atoms. Ground-level ozone 
is generally not emitted directly from a vehicle's exhaust or an 
industrial smokestack, but is created by a chemical reaction between 
NOX and VOCs in the presence of sunlight and high ambient 
temperatures. Thus, ozone is known primarily as a summertime air 
pollutant. NOX and VOCs are precursors of ozone. Motor 
vehicle exhaust and industrial emissions, gasoline vapors, chemical 
solvents and natural sources emit NOX and VOCs. Urban areas 
tend to have high concentrations of ground-level ozone, but areas 
without significant industrial activity and with relatively low 
vehicular traffic are also subject to increased ozone levels because 
wind carries ozone and its precursors hundreds of miles from their 
sources.
    Repeated exposure to ozone pollution may cause lung damage. Even at 
very low concentrations, ground-level ozone triggers a variety of 
health problems including aggravated asthma, reduced lung capacity, and 
increased susceptibility to respiratory illnesses like pneumonia and 
bronchitis. It can also have detrimental effects on plants and 
ecosystems.

D. Background of the Texas SIP for the DFW Area

    The original Texas SIP was submitted to EPA by the Texas Air 
Control Board (renamed twice and known today as the TCEQ), on January 
31, 1972. On May 31, 1972, EPA conditionally approved the SIPs for all 
States in Volume 37 of the Federal Register beginning on page 10842 
(denoted 37 FR 10842). The Texas SIP was conditionally approved (37 FR 
10842, 10895) and the status of the Texas SIP was codified in Title 40, 
Part 52 of the U.S. Code of Federal Regulations (denoted 40 CFR 52), 
Subpart SS, sections 52.2270 to 52.2280. Since 1972, many revisions for 
the DFW area have been submitted by the State and approved by EPA. 
These include numerous control measures implemented under the 1-hour 
ozone standard to reduce NOX and VOC emissions from area, 
point and mobile

[[Page 40207]]

sources; the Post-1996 Rate-of-Progress (ROP) Plan; and the 15% ROP 
Plan. As a result of the implementation of these measures, the area's 
1-hour ozone values have declined significantly in the past several 
years; the 2004-2006 1-hour design value for the DFW area is 124 parts 
per billion (ppb) and the preliminary \1\ 1-hour design value for 2005-
2007 is also 124 ppb, which meets the 1-hour standard, although this 
standard was revoked in 2005.
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    \1\ The value is considered preliminary because TCEQ has not 
certified that it has completed the quality assurance and quality 
control checks. We expect the data certification by by July 1, 2008.
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E. Background of This SIP Revision To Address the 1997 Ozone NAAQS

    On July 18, 1997, EPA promulgated a revised 8-hour ozone standard 
of 0.08 parts per million (ppm), which is more protective than the 
previous 1-hour ozone standard (62 FR 38855).\2\ Under EPA regulations 
at 40 CFR part 50, Appendix I, the 1997 8-hour ozone standard is 
attained when the 3-year average of the annual fourth highest daily 
maximum 8-hour average ambient ozone concentrations is less than or 
equal to 0.08 ppm (i.e., 0.084 ppm when rounding is considered). For 
ease of communication, many reports of ozone concentrations are given 
in parts per billion (ppb); ppb = ppm x 1,000. Thus, 0.084 ppm becomes 
84 ppb.
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    \2\ EPA issued a revised 8-hour ozone standard on March 27, 2008 
(73 FR 16436). The designation and implementation process for that 
standard is just starting and does not affect EPA's action here.
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    The EPA published the 1997 8-hour ozone designations and 
classifications on April 30, 2004 (69 FR 23858). The DFW area was 
designated nonattainment, classified as moderate, and includes nine 
counties: Collin, Dallas, Denton, and Tarrant counties (these 
constitute the former 1-hour ozone NAA, hereafter referred to as the 
core counties), and Ellis, Johnson, Kaufman, Parker and Rockwall 
counties. The effective date of designation for the 1997 8-hour ozone 
NAAQS was June 15, 2004. The attainment demonstration for the DFW area 
was due by June 15, 2007 and was submitted on time. The attainment date 
for the DFW area is June 15, 2010.
    EPA also published the first rule governing implementation of the 
8-hour ozone standard (Phase 1 Rule) on April 30, 2004 (69 FR 23951). 
The Phase 1 Rule addresses classifications for the 8-hour NAAQS; 
revocation for the 1-hour NAAQS; how anti-backsliding principles will 
ensure continued progress toward attainment of the 8-hour NAAQS; 
attainment dates; and the timing of emissions reductions needed for 
attainment.
    On December 22, 2006, the U.S. Court of Appeals for the District of 
Columbia Circuit vacated EPA's Phase 1 Rule in South Coast Air Quality 
Management Dist. v. EPA, 472 F.3d 882 (D.C. Cir. 2006). On June 8, 
2007, in response to several petitions for rehearing, the court 
modified the scope of vacatur of the Phase 1 Rule. See 489 F.3d 1245 
(D.C. Cir. 2007), cert. denied, 128 S.Ct. 1065 (2008). The court 
vacated those portions of the Phase 1 Rule that provide for regulation 
of the 1997 8-hour ozone NAAQS in some nonattainment areas under 
Subpart 1 in lieu of Subpart 2 and that allowed areas to revise their 
SIPs to no longer require certain programs as they applied for purposes 
of the 1-hour NAAQS; new source review, section 185 penalties, and 
contingency plans for failure to meet RFP and attainment milestones. 
The decision does not affect the requirements for areas classified 
under subpart 2, such as the DFW area, to submit an attainment 
demonstration plan for 1997 8-hour ozone NAAQS and to attain the NAAQS 
no later than the outside date for attainment required for the area's 
classification.
    EPA published a second rule governing implementation of the 8-hour 
ozone standard (Phase 2 Rule) on November 29, 2005 (70 FR 71612), as 
revised on June 8, 2007 (72 FR 31727). The Phase 2 Rule addresses, 
among other things, the following control and planning obligations as 
they apply to areas designated nonattainment for the 1997 8-hour ozone 
NAAQS: RACT, RACM, photochemical modeling, and attainment 
demonstrations. EPA issued the Phase 2 Rule so States and Tribes would 
know how these statutory control and planning obligations apply and 
when SIP revisions are due for these obligations so that the States 
could develop timely submissions consistent with the statutory 
obligations and attain the NAAQS as expeditiously as practicable, but 
no later than the attainment dates specified for each area's 
classification. Litigation on the Phase 2 Rule is pending before the 
D.C. Circuit Court of Appeals.
    On May 23, 2007, the TCEQ approved revisions to the SIP for the DFW 
8-hour ozone nonattainment area. The SIP revisions were submitted to 
EPA on May 30, 2007 and supplemented on April 23, 2008. Today we are 
addressing the 1997 8-hour ozone attainment demonstration SIP for the 
DFW area and a RACT finding for both the 1-hour and 1997 8-hour ozone 
standards.

F. What Is an Attainment Demonstration?

    In general, an ozone attainment demonstration includes a 
photochemical modeling analysis and other evidence (referred to as 
``weight of evidence'') showing how an area will achieve the standard 
as expeditiously as practicable, but no later than the attainment date 
specified for its classification. For purposes of the 8-hour ozone 
standard, a determination of attainment (or failure to attain) is based 
on the most recent three complete years of data prior to the area's 
attainment date. Thus, since the DFW moderate area has a maximum 
attainment date of June 15, 2010, the most recent three years of data 
for determining attainment in the DFW area will be from the three 
preceding calendar years, i.e., the air quality monitoring data from 
2007, 2008 and 2009. Alternatively, an area may qualify for up to two 
one-year extensions. The first extension can be granted if the area's 
4th highest daily 8-hour average is 0.084 ppm or less. The second can 
be granted if the 4th highest value averaged over the attainment year 
and the extension year is 0.084 ppm or less (40 CFR 51.907).
    To demonstrate attainment, an area must predict that emissions 
during the ozone season preceding the attainment date will meet the 
standard. EPA requires areas to implement all the measures necessary to 
demonstrate attainment as expeditiously as practicable, but no later 
than the start of the final complete ozone season preceding the area's 
attainment date (40 CFR 51.908). The DFW area's ozone season runs from 
March 1st through October 31st (62 FR 30270, June 3, 1997 and 40 CFR 
part 58, Appendix D); therefore, all of the control strategies relied 
upon in the attainment demonstration must be implemented by March 1, 
2009.
    In addition to the approvable modeling and weight of evidence 
components of an attainment demonstration SIP, for the attainment 
demonstration SIP to be approvable, it must contain the following 
elements which must also be approved: attainment MVEBs for 
transportation conformity purposes; the measures relied on as necessary 
to demonstrate attainment; RACM; an RFP plan and the RFP/failure-to-
attain contingency measures requirements for the area. (See Sierra Club 
v. EPA, 294 F.3d 155, 163 (D.C. Cir. 2002).

[[Page 40208]]

V. Evaluation of the DFW 1997 8-Hour Ozone Attainment Demonstration SIP

    Below, we discuss the statutory and regulatory requirements that 
prescribe our review of the State's attainment demonstration, the 
elements in the State's submittal, and our evaluation of those elements 
comprising the attainment demonstration SIP. Separate from our review 
of the State's attainment demonstration SIP is our review of the 
State's VOC RACT demonstration, and we discuss the VOC RACT statutory 
and regulatory requirements in section VI.

A. Legal Requirements for Approval

    The Act requires SIPs for nonattainment areas to demonstrate that 
the area will attain the 8-hour ozone standard as expeditiously as 
practicable, but no later than outside dates established by the Act. 
The Phase 2 Rule provides timing and guidance for this requirement for 
the 1997 8-hour ozone standard and identifies the modeling guidance 
available to make the demonstration. Moderate 1997 8-hour ozone 
nonattainment areas must attain the standard no later than June 15, 
2010. An attainment demonstration SIP must include technical analyses 
to locate and identify sources of emissions that are causing violations 
of the NAAQS within nonattainment areas; adopted measures with 
schedules for implementation and other means and techniques necessary 
and appropriate for attainment; and contingency measures required under 
section 172(c)(9) of the Act that can be implemented without further 
action by the State or the Administrator to cover failures to meet RFP 
milestones and/or attainment. The attainment demonstration SIP must 
include a demonstration that the area is meeting RACM. An attainment 
demonstration SIP must also identify MVEBs for transportation 
conformity purposes. EPA's regulations at 40 CFR 51.908(c) specifically 
require that areas classified as moderate and above submit a modeled 
attainment demonstration based on a photochemical grid modeling 
evaluation or any other analytical method determined by the 
Administrator to be at least as effective as photochemical modeling. 
Section 51.908(c) also requires each attainment demonstration to be 
consistent with the provisions of section 51.112, including Appendix W 
to 40 CFR part 51 (i.e., ``EPA's Guideline on Air Quality Models,'' 68 
FR 18440, April 15, 2003). See also EPA's ``Guidance on the Use of 
Models and Other Analyses in Attainment Demonstrations for the 8-hour 
Ozone NAAQS,'' October 2005 and ``Guidance on the Use of Models and 
Other Analyses for Air Quality Goals in Attainment Demonstrations for 
Ozone, PM2.5, and Regional Haze,'' April 2007 (hereafter referred to as 
``EPA's 2005 and 2007 A.D. guidance documents''), which describe 
criteria that an air quality model and its application should meet to 
qualify for use in an 8-hour ozone attainment demonstration. For the 
detailed review of modeling and the Weight of Evidence (WOE) analyses 
and EPA's conclusions on the DFW 8-hour Ozone Attainment Demonstration 
see the ``Modeling and Other Analyses Attainment Demonstration'' 
(MOAAD) Technical Support Document (TSD). The MOAAD TSD also includes a 
complete list of applicable modeling guidance documents. These guidance 
documents provide the overall framework for the components of the 
attainment demonstration, how the modeling and other analyses should be 
conducted, and overall guidance on the technical analyses for 
attainment demonstrations.
    As with any predictive tool, there are inherent uncertainties 
associated with photochemical modeling. EPA's guidance recognizes these 
limitations and provides approaches for considering other analytical 
evidence to help assess whether attainment of the NAAQS is likely. This 
process is called a WOE determination. EPA's modeling guidance (updated 
in 1996, 1999, and 2002) discusses various WOE approaches. EPA's 
modeling guidance has been further updated in 2005 and 2007 for the 
1997 8-hour attainment demonstration procedures to include a WOE 
analysis as an integral part of any attainment demonstration. This 
guidance strongly recommends that all attainment demonstrations include 
supplemental analyses beyond the recommended modeling. These 
supplemental analyses would provide additional information such as data 
analyses, and emissions and air quality trends, which would help 
strengthen the overall conclusion from the photochemical modeling. A 
WOE analysis is specifically recommended to be included as part of any 
attainment demonstration SIP where the modeling results predict Future 
Design Values (FDVs) ranging from 82 to less than 88 ppb (EPA's 2005 
and 2007 A.D. guidance documents). EPA's interpretation of the Act to 
allow a WOE analysis has been upheld. See 1000 Friends of Maryland v. 
Browner, 265 F.3d 216 (4th Cir. 2001) and BCCA Appeal Group v. EPA, 355 
F.3d 817 (5th Cir. 2003).
    Since much of TCEQ's initial work was conducted prior to the 2005 
guidance document, the earlier draft 1999 modeling guidance document 
(EPA-454/R-99-004, May 1999; ``DRAFT Guidance on the Use of Models and 
Other Analyses in Attainment Demonstrations for the 8-Hour Ozone 
NAAQS'') was also used by TCEQ and EPA prior to the October 2005 
guidance issuance. There are two main changes compared to EPA's 
modeling attainment demonstration guidance issued in 1991. First, EPA 
recommends a modeled attainment test in which model predictions are 
used in a relative rather than absolute sense. Second, the role of the 
WOE determination, when used, has been expanded. That is, where the use 
of WOE was previously considered optional, it is now strongly 
recommended as an integral part of an attainment demonstration in 
addition to the modeled attainment test.
    TCEQ submitted the DFW attainment demonstration SIP with 
photochemical modeling and WOE analyses. The results of the 
photochemical modeling and WOE analyses are discussed below in 
Subsection B. The projected growth rates and emissions reductions (or 
increases) for the control measures and other means relied upon in the 
modeling are discussed in Subsection C.

B. Eight-Hour Attainment Demonstration Modeling and Weight of Evidence

a. What Were the Results of the Photochemical Modeling Attainment 
Demonstration?
i. What Is a Photochemical Grid Model?
    Photochemical grid models are the state-of-the-art method for 
predicting the effectiveness of control strategies in reducing ozone 
levels. The models use a three-dimensional grid to represent conditions 
in the area of interest. TCEQ chose to use the Comprehensive Air Model 
with Extensions (CAMx), Version 4.31 photochemical model for this 
attainment demonstration SIP. The model is based on well-established 
treatments of advection, diffusion, deposition, and chemistry. Another 
important feature is that NOX emissions from large point 
sources can be treated with the plume-in-grid sub-model that helps 
avoid the artificial diffusion that occurs when point source emissions 
are inserted into a grid volume. The use of the newer version improves 
the plume dispersion algorithms and adds full NOX and VOC 
chemistry in the plumes. TCEQ has used the CAMx model in other SIPs and 
EPA has approved many SIPs using CAMx based modeling analyses. Part 51 
Appendix W indicates that photochemical grid models should be used for 
ozone SIPs and lists a

[[Page 40209]]

number of factors to be considered in selecting a photochemical grid 
model to utilize. EPA has reviewed TCEQ reasons for selecting CAMx and 
EPA agrees with the choice by TCEQ to utilize CAMx for this SIP.
    In this case, TCEQ has developed a grid system that consists of 
three nested grids. The outer grid stretches from west of Austin to 
Maine and parts of the Atlantic Ocean to the east, and from parts of 
southern Canada in the north to the southern tip of Texas and the Gulf 
of Mexico on the southern edge. The model uses nested grid cells of 36 
km on the outer portions, 12 km in east Texas and portions of nearby 
States and a 4-km grid cell covering the DFW Nonattainment Area. For 
more information on the modeling domain, see the MOAAD TSD. The model 
simulates the movement of air and emissions into and out of the three-
dimensional grid cells (advection and dispersion); mixes pollutants 
upward and downward among layers; injects new emissions from sources 
such as point, area, mobile (both on-road and nonroad), and biogenic 
into each cell; and uses chemical reaction equations to calculate ozone 
concentrations based on the concentration of ozone precursors and 
incoming solar radiation within each cell. Air quality planners choose 
historical time period(s) (episode(s)) of high ozone levels to apply 
the model. Running the model requires large amounts of data inputs 
regarding the emissions and meteorological conditions during an 
episode.
    Modeling to duplicate conditions during an historical time period 
is referred to as the base case modeling and is used to verify that the 
model system can predict historical ozone levels with an acceptable 
degree of accuracy. It requires the development of a base case 
inventory, which represents the emissions during the time period for 
the meteorology that is being modeled. These emissions are used for 
model performance evaluations. Texas modeled a 1999 episode, so the 
base case emissions and meteorology are for 1999. If the model can 
adequately replicate the ozone levels in the base case and responds 
adequately to diagnostic tests, it can then be used to project the 
response of future ozone levels to proposed emission control 
strategies.
ii. What Episode Did Texas Choose To Model?
    Texas chose an historical episode, August 13-22, 1999, that had 
been previously used in modeling for the Early Action Compact modeling 
of the Northeast Texas Area. The episode encompasses ten days with 8-
hour ozone exceedances every day, except for the first day which is one 
of the two spin-up days. The first two days are considered spin-up days 
that are usually not used in the modeling analysis because it 
ordinarily takes 1-2 days to work out the initial condition biases. Of 
the eight days (ten days minus the two spin-up days) that have 
exceedances, all but one day have multiple monitors with exceedances 
(2-7 of the nine monitors). On average, the eight exceedance days have 
four monitors exceeding the standard each day. This episode contains a 
variety of meteorological conditions which resulted in high 
concentrations of ozone in the area as measured on both a 1-hour and 8-
hour basis, and many of the days had conditions similar to the 
predominant types of meteorological conditions that yield high ozone in 
the DFW NAA.
    We evaluated Texas' episode selection for consistency with our 
modeling guidance (1991, Draft 1999, 2005, and 2007 versions). Among 
items that we considered were the ozone levels during the selected 
period compared to the Design Value \3\ (DV) at the time; how did the 
meteorological conditions during the proposed episode match with the 
conceptual model of ozone exceedances that drive the area's DV; were 
enough days modeled; and was the time period selected robust enough to 
represent the area's problem for evaluating future control strategies. 
EPA's guidance indicates that all of these items should be considered 
when evaluating available episodes and selecting episodes to be 
modeled. EPA believes that the episode from August 13-22, 1999, is an 
acceptable episode for development of the 8-hour ozone attainment plan. 
It has a number of meteorological conditions that match the conditions 
that yield high ozone in the conceptual model for the DFW NAA, and was 
among the episode periods evaluated with the highest number of ozone 
exceedances. In selecting episodes, it is advantageous to select 
episodes with several exceedance days and with multiple monitors 
exceeding the standard each day when possible. This episode was among 
the best episodes for the periods evaluated when the selection was 
being conducted initially, and also had the benefit that significant 
work was being conducted for this period for the Early Action Compact 
for the Tyler/Longview/Marshall area of Northeast Texas. See the MOAAD 
TSD for further discussion and analysis.
---------------------------------------------------------------------------

    \3\ The design value is the 3-year average of the annual fourth 
highest daily maximum 8-hour average ozone concentration (40 CFR 50, 
Appendix D.
---------------------------------------------------------------------------

iii. How Well Did the Model Perform?
    Model performance is a term used to describe how well the model 
predicts the meteorological and ozone levels in an historical episode. 
EPA has developed various diagnostic, statistical and graphical 
analyses that TCEQ has performed to evaluate the model's performance to 
determine if the model is working adequately to test control 
strategies. TCEQ has done many analyses of both interim model runs and 
the final base case model run and deemed the model's performance 
adequate for control strategy development. As described below, we agree 
with their assessment.
    From 2003 to 2005, several iterations of the modeling were 
preformed incorporating various improvements to the meteorological 
modeling, the 1999 base case emissions inventory, and other model 
parameters. These iterations totaled over 40 combinations as TCEQ 
worked to refine the modeling. EPA reviewed these interim modeling 
steps and provided comments and suggestions. When TCEQ felt the model 
performance was acceptable, EPA (Region 6 and the Office of Air Quality 
Planning and Standards) and TCEQ had a detailed meeting on February 1, 
2005 to cover all aspects of the episode selected and model performance 
(meteorological, emissions, and photochemical). TCEQ shared a compact 
disc with detailed statistical and graphical analysis of the different 
modeling (meteorology and photochemical). This data included analysis 
of meteorological outputs compared to benchmark statistical parameters 
that TCEQ previously developed as target values that are being used in 
many areas of the country. TCEQ also shared graphical analyses of the 
meteorology. TCEQ also shared extensive analyses of the photochemical 
modeling for several base case modeling runs that included: diagnostic 
tests with reductions/increases of precursor emissions, time series of 
1-hour and 8-hour ozone, EPA 1-hour statistics, EPA 8-hour statistics, 
ozone spatial plots, quantile-quantile plots, ozone pre-cursor data, 
and ozone animations.
    After extensive review, EPA was satisfied that the meteorological 
modeling was meeting most of the statistical benchmarks, and was 
transporting air masses in the appropriate locations for most of the 
days of the episode. EPA also conducted a thorough review of the 
model's performance in predicting ozone and ozone pre-cursors and found 
that

[[Page 40210]]

performance was within the recommended 1-hour ozone statistics for 
almost all days and all statistics. We also evaluated the 8-hour 
statistics, results of diagnostic and sensitivity tests, and multiple 
graphical analyses and determined that overall the ozone performance 
was acceptable for Texas to move forward with future year modeling and 
development of an attainment demonstration. EPA's acceptance of the 
modeling is documented in a June 6, 2005 letter.
    Subsequently, TCEQ made further minor refinements to the modeling 
which are discussed in the MOAAD TSD. EPA agrees that after these minor 
refinements, the overall model performance remains acceptable. The 
final base case modeling evaluation, Run 46 using CAMx 4.31, further 
reduced negative bias and reduced the total errors in the modeling 
system. EPA agrees that the overall model performance (Run 46) is 
adequate, but notes that even with the refinements, the modeling still 
tends to have some bias on the higher ozone days. This bias may make 
future year assessments conservative, i.e., the amount of ozone 
reduction predicted is likely less than will actually occur, if the 
modeling is not fully replicating local ozone generation. See the MOAAD 
TSD for further analysis.
iv. Once the Base Case Is Determined To Be Acceptable, How Do You Use 
the Modeling for the Attainment Demonstration?
    Once the base case modeling is determined to be consistent with 
EPA's guidance and acceptable for replicating the ozone levels observed 
in the 1999 episode period, the modeling can be used as the basis for 
developing the future year modeling. TCEQ then evaluated the base case 
emission inventory, and made some minor adjustments to the inventory to 
account for things that would not be expected to occur again or that 
were not normal (example: inclusion of EGUs that were not operating due 
to temporary shutdown during the base case period but were expected to 
be operating in 2009). This emission inventory is called the 1999 
baseline emission inventory. The photochemical model is then executed 
again to obtain a 1999 baseline model projection.
    EPA's guidance recommends using 2002 as the baseline inventory 
year, but there are several possible methodologies available to 
calculate baseline design values. For example, if a state models 
episodes from other years it can project (or back-cast) to 2002 to 
provide a starting point for future year projections. Alternatively, a 
state may use a baseline year earlier than 2002 for the following 
reasons: (1) Availability of air quality and meteorological data from 
an intensive field study, (2) the desire to use meteorological data 
that may be ``more representative'' of typical ozone conditions 
compared to the baseline design value period, and (3) availability of a 
past modeling analysis in which the model performed well. Texas chose 
1999 as the baseline year. There was extensive air quality and 
meteorological modeling available for the 1999 episode from Early 
Action Compact Modeling in Northeast Texas; 1999's meteorology 
represented typical ozone conditions. Therefore, EPA and TCEQ weighed 
the pros and cons and concurred, based upon the above-noted reasons, 
that it was not necessary to attempt to project to a 2002 baseline 
emission inventory in this specific case.
    The baseline emission inventory is also used as the basis, along 
with other data, to project and estimate the future case emission 
inventory along with consideration of any state and Federal regulations 
that result in emission changes from the 1999 period. Since DFW is 
classified as a moderate NAA, the attainment deadline is as 
expeditiously as practicable but no later than June 15, 2010. Any 
emissions reductions must be implemented no later than the beginning of 
the previous ozone season; in this case, March 1, 2009, which is the 
beginning of the final full ozone season preceding the attainment date, 
if the reductions are to support attainment. The meteorological 
modeling that has been reviewed and determined to be acceptable for the 
base case is also used for the meteorological conditions in the future 
year modeling (no changes are made). The future case modeling uses the 
base case meteorology and estimated 2009 emissions to assess the impact 
of economic growth in the region and State and Federal control measures 
that will become effective during the modeling period from 1999 to 
March 1, 2009. After the State develops a 2009 future baseline emission 
inventory, photochemical modeling is conducted to get the 2009 baseline 
ozone levels. The State then begins conducting modeling sensitivities 
and modeling assessments of potential additional emission reductions to 
aid in the planning of a control strategy that will demonstrate 
attainment.
    The 8-hour ozone modeling guidance changed the attainment test to 
use the modeling analysis in a relative sense instead of an absolute 
sense as was done in 1-hour ozone demonstrations. To predict ozone 
levels in the future, we estimate a value that we refer to as the FDV. 
First, we need to calculate a Base Design Value (BDV). The BDV is 
calculated for each monitor that was operating in the base period by 
averaging the three DVs that include the base year (1999); that would 
be the DV for 1997-1999, 1998-2000, and 1999-2001 to result in a 
center-weighted BDV.
    To estimate the FDV, a value is also calculated for each monitor 
that is called the Relative Response Factor (RRF) using the baseline 
and future modeling. The RRF value is calculated by taking the ratio of 
the sum of the daily highest 8-hour ozone value predicted around a 
monitor in 2009 and dividing by the sum of the daily highest 8-hour 
ozone value predicted around the same monitor in the 1999 baseline 
analysis. ``Around the monitor'' for DFW modeling (4km grid) is defined 
as the 7x7 array of grid cells surrounding the monitor (with the 
monitor in the middle). EPA's guidance indicates that only days that 
had a baseline value above a threshold concentration (TCEQ used 70 ppb, 
which is the minimum value indicated by EPA guidance) should be used in 
the RRF calculations. For each monitor, EPA recommends adding up all 
the daily maximum 8-hour ozone values (for days that the maximum 8-hour 
ozone value in the baseline were above the threshold in the area around 
the monitor) and dividing that sum by the sum of the daily maximum 8-
hour ozone values predicted in 2009 around the monitor. This 
calculation yields the RRF for that monitor. The RRF is then multiplied 
by the Base Design Value (BDV) for that monitor to yield the FDV for 
that monitor. This step is conducted for each monitor. The modeled 
values for each monitor may be calculated to the hundredths of a ppb 
which is rounded to get to tenths of a ppb, which is then truncated to 
an integer (in ppb) at the end of the process (as recommended by EPA's 
guidance). The truncated values are included in the tables in this 
notice (Example: Modeled value of 84.94 is rounded to 84.9 and then 
truncated to 84; Example 2: Modeled value of 84.95 is rounded to 85.0 
and then truncated to 85).
v. What Modeling Approaches Were Used for This Attainment 
Demonstration?
    TCEQ submitted photochemical modeling labeled Combo 10 in its 
attainment demonstration SIP. Combo 10 contains the control measures 
outlined in Section D, including additional control measures with 
compliance deadlines of March 1, 2010. The 2010 compliance dates apply 
to

[[Page 40211]]

certain rich-burn natural gas fired engines for oil and gas compressors 
in 33 Texas counties, all of which are outside the DFW NNA. Despite the 
fact that the controls noted above are not required to be implemented 
until 2010, Combo 10 assumes that all control measures will be in 
effect by the beginning of the 2009 ozone season. TCEQ assumed that 
early compliance would occur as a result of incentive grants for early 
compliance provided by the State Legislature. Texas SB2000 provides an 
appropriation of $4 million to compensate operators of the regulated 
oil and gas compressors who comply with new emission reduction 
standards early. There is also a large population of emission units in 
this category and it is also likely that a percentage of these will be 
controlled before the 2009 ozone season, or before the beginning of the 
core part of the ozone season. Due to the large number of emission 
units in this category and the incentive for early compliance, TCEQ 
believes these units will provide significant reductions by 2009.
    A small portion of the point source NOX Controls in the 
DFW NAA, that yield about 2.4 tpd of NOX reductions, also 
have 2010 compliance dates. TCEQ did not attempt to assess the 
potential impact of not having these additional point source reductions 
in place by the beginning of the 2009 ozone season. The 2.4 tpd of 
NOX reductions from these sources is less than 10% of the 
NOX emission reductions adopted for the DFW NAA. EPA also 
notes that some of these 2.4 tpd NOX reductions are in the 
western part of the DFW NAA and would not directly affect the modeled 
impact at the monitors with the highest modeled FDVs (Frisco and Denton 
monitors) for this episode, but would be expected to help reduce ozone 
impacts at other monitors in Parker and Tarrant counties that have been 
added to the DFW area monitoring network since 1999.
    For a more complete description of the modeling procedures 
conclusions and EPA's evaluation of these procedures and conclusions, 
see the MOAAD TSD in the Docket for this action (EPA-RO6-OAR-2007-
0524).
vi. What Did the Results of TCEQ's Combo 10 Modeling Show?
    The results of modeling the final control strategy runs are shown 
in Table 1. As previously discussed, the State submitted modeling 
(Combo 10) that took into account all the reductions from adopted 
regulations, including those with 2010 compliance dates. TCEQ has 
proposed an alternative RRF calculation method that calculated a daily 
RRF for each monitor and then averaged the values to yield the RRF that 
was multiplied by the BDV to yield the FDV. In the following Table 1, 
we evaluate the model FDV calculations using both EPA's guidance method 
for RRF calculation and the alternate RRF calculation approach that 
TCEQ had developed. Details on the two methods are included in the TSD. 
For most monitors, the alternate FDV calculations make only minor 
differences. We have calculated the FDVs in the following tables using 
the final truncated numbers in accordance with EPA guidance. Since the 
TCEQ RRF calculation method did not make significant differences in the 
FDVs and with the truncation to whole numbers, we have used the TCEQ 
RRFs for the final assessment with consideration of the FDVs using 
EPA's RRF method. The results of EPA's RRF method are contained in the 
MOAAD TSD. Table 1 includes the modeling projections prior to 
evaluating any other modeling runs, any additional model based 
projections, and any WOE considerations for the Combo 10 modeling run. 
Table 1 also includes the results from the two methodologies to 
calculate the FDVs.

                   Table 1.--June 15, 2007 SIP Control Strategy Modeling Projections for 2009
----------------------------------------------------------------------------------------------------------------
                                                                                         FDV 1999 Combo 10
                            Monitor                                  BDV 1999    -------------------------------
                                                                                        EPA            TCEQ
----------------------------------------------------------------------------------------------------------------
Frisco.........................................................            100.3              89              88
Dallas Hinton C60..............................................             92                85              85
Dallas North C63...............................................             93                84              84
Dallas Exec C402...............................................             88                78              78
Denton.........................................................            101.5              88              88
Midlothian.....................................................             92.5              83              83
Arlington......................................................             90.5              80              80
Ft Worth C13...................................................             98.3              85              85
Ft Worth C17...................................................             96                84              84
----------------------------------------------------------------------------------------------------------------

    The first column is the Base DV for the 1999 period that is used 
with the modeling RRFs for calculating the FDVs. For Combo 10, the 
analysis shows that 5 of the 9 monitors are projected to be in 
attainment (at or below 84 ppb); two monitors (Ft. Worth C13 and Dallas 
Hinton C60) are projected to be very near attainment with 85 ppb; and 
projections for the other two monitors are 88 ppb for Denton and 88/89 
ppb for the Frisco monitor. As shown in Table 1, the FDVs are on the 
order of 8-12 ppb less than the Base DVs, which is a large reduction in 
ozone levels due to existing State and Federal measures and the newly 
adopted measures.
    For a more complete description of the modeling procedures 
conclusions and EPA's evaluation of these procedures and conclusions, 
see the MOAAD TSD in the Docket for this action (EPA-RO6-OAR-2007-
0524).
    In addition to the modeling results, TCEQ has presented other 
evidence to demonstrate that attainment will be reached. These 
additional WOE analyses are evaluated in Section 2 below. Since TCEQ's 
May 30, 2007 submittal, TCEQ has also provided additional information 
dated April 23, 2008 that supplements the modeling analysis (discussed 
in part h below) and also the WOE (also discussed in section 2 below).
vii. Evaluation of Other Modeling Projections Without Benefit of 
Measures With a 2010 Compliance Date
    Due to our concerns that not all control measures relied on in the 
Combo 10 analysis are required to be implemented prior to the 2009 
ozone season, we also reviewed an alternative photochemical modeling 
analysis. The additional modeling, which we refer to as Photochemical 
Dispersion Modeling Reanalysis 2009 (PDMR 2009), evaluates the ozone 
levels in 2009 based on the TCEQ control measures with

[[Page 40212]]

compliance dates of March 1, 2009 or earlier and does not consider the 
impact from the adopted rules that have compliance dates after March 1, 
2009. The adopted SIP included 2.4 tpd of NOX emission 
reductions in the DFW NAA with a 2010 compliance date, while the 
adopted reductions within the DFW NAA with a 2009 compliance date of 
March 1, 2009 or earlier yield 23.48 tpd of NOX reductions. 
The adopted SIP also included 22.4 tpd of NOX reductions 
outside the DFW NAA due to the control of rich-burn compressor engines 
with a compliance date after March 1, 2009. Since these emission 
reductions occur outside the DFW NAA, they would not be expected to 
yield the same amount of ozone benefit as similar reductions in the DFW 
NAA would yield. The PDMR 2009 modeling helps to assess the potential 
impacts of these 2010 compliance rules.
    This evaluation of PDMR 2009 sets the lower bound of model 
predictions for the FDV in 2009 and the Combo 10 run sets the upper 
bound. This approach is consistent with attempting to consider the 
bounds of potential benefit from the adopted measures included in the 
SIP.
    Table 2 includes the modeling projections for both the Combo 10 and 
PDMR 2009 modeling runs.

                   Table 2.--June 15, 2007 SIP Control Strategy Modeling Projections for 2009
----------------------------------------------------------------------------------------------------------------
                                                                                   FDV Combo 10    FDV PDMR 2009
                            Monitor                                  BDV 1999    -------------------------------
                                                                                     TCEQ RRF        TCEQ RRF
----------------------------------------------------------------------------------------------------------------
Frisco.........................................................            100.3              88              88
Dallas Hinton C60..............................................             92                85              85
Dallas North C63...............................................             93                84              85
Dallas Exec C402...............................................             88                78              79
Denton.........................................................            101.5              88              88
Midlothian.....................................................             92.5              83              84
Arlington......................................................             90.5              80              81
Ft Worth C13...................................................             98.3              85              85
Ft Worth C17...................................................             96                84              85
----------------------------------------------------------------------------------------------------------------

    For PDMR 2009, the analysis shows that 3 of the 9 monitors are 
projected to be in attainment (at or below 84 ppb); four monitors (Ft. 
Worth C13, Ft. Worth C17, Dallas North C63, and Dallas Hinton C60) are 
projected to be very near attainment with 85 ppb; and projections for 
the other two monitors are 88 ppb for the Denton and Frisco monitors. 
This analysis indicates a slightly worse air quality picture than the 
results from the Combo 10 analysis. The FDVs for several monitors were 
higher, but the actual difference is only a few tenths of a ppb at most 
monitors of concern. The largest difference between the PDMR 2009 
modeling and the Combo 10 modeling was an increase of 0.3 ppb at the 
Frisco monitor.
    As previously discussed, reductions from rules with a March 2010 
compliance date are included in the Combo 10 run. Due to the incentives 
for early compliance and consideration that some sources will likely be 
controlled early, we conclude some of the reductions from rules with a 
March 2010 compliance date will likely be completed early. Therefore, 
we have evaluated the modeling outputs based on an approach that looks 
at both the PDMR 2009 outputs, which predicts ozone levels that are 
slightly worse than what actually will occur and Combo 10 outputs which 
may be somewhat optimistic. For most monitors, the difference between 
the PDMR 2009 and Combo 10 outputs is only a few tenths of a ppb of 
ozone. For more details see the MOAAD TSD for this notice.
viii. Refinements and Adjustments to Future Year (2009) Emission 
Inventory and Modeling-Based Projected Changes to the SIP Modeling FDVs
    Texas provided supplemental information to EPA on April 23, 2008 
that expands and confirms information in the May 30, 2007 SIP 
submittal. See TCEQ's April 23, 2008 letter in the docket. The letter 
addresses the issues discussed below related to the airport emission 
inventory, DERCs and back-up generators, demonstrating that the 
projected emissions in these categories will be lower in 2009 than the 
projections in the May 30, 2007 SIP submittal. To support the 
adjustment to the DERC projections, Texas also provided a commitment 
letter on June 13, 2008 to adopt a SIP revision to limit the use of 
DERCs that is evaluated below and in section V-D of this notice. This 
commitment was made by TCEQ in order to strengthen the attainment 
demonstration.
    Regarding airport emissions, TCEQ provided a report performed by 
Eastern Research Group for Love Field, a Dallas inner city airport, 
which indicated that emission projections based on more recent data are 
much lower in 2009 than emission projections relied on in the Combo 10 
and PDMR 2009 modeling. The emissions are lower primarily due to 
changes in market demand post-- 9/11/2001 and the accelerated 
replacement of engines which occurred in order to reduce fuel usage 
because of the drastic increase in fuel costs over the last few years. 
Projections at Love Field were also impacted by changes in the Wright 
Amendment Restrictions, a Federal law restricting flights in and out of 
the airport that imposed restrictions on the number of gates that could 
be operated (Pub. L. 109-352). TCEQ and North Central Texas Council of 
Governments (NCTCOG) have provided EPA with updated information which 
became available since the May 30, 2007 submittal which refines the 
2009 future year emission projections for Love Field and also the DFW 
International Airport (DFWIA). Both airports agree with their revised 
projections. With the reduced projections at DFWIA and Love Field, 
total airport emissions for all airports in the DFW NAA are reduced 
from 24.05 tpd (the amount that was included in the attainment 
demonstration modeling submitted May 30, 2007) to a lower emission 
totals of 14.66 tpd (aircraft and ground support equipment). In other 
words, the new estimates result in a 9.39 tpd airport emission 
inventory reduction from the May 30, 2007 SIP modeling estimates for 
the two airports. We have reviewed the updated information and agree 
that 14.66 tpd NOX (a decrease of 9.39 tpd from the May 30, 
2007 submittal values) represents a more accurate estimate of the 
projected emissions from the DFW NAA airports.

[[Page 40213]]

    Consistent with EPA's guidance, sections 12 and 16 of ``Improving 
Air Quality with Economic Incentive Programs'' (EPA-452/R-01-001, 
January 2001), TCEQ included in the 2009 modeled projections, all of 
the Emission Reduction Credits (ERCs) and Discrete Emission Reduction 
Credits (DERCs) in the bank. EPA guidance calls for emission credits 
that are being carried in the emissions bank to be included in modeled 
projections because these emissions will come back in the air when the 
credits are used. The TCEQ Bank currently holds 20.4 tpd of DERCs. Upon 
review of the DERC values included in the modeling, TCEQ felt that the 
inclusion of the entire balance of the DERC bank was overly 
conservative based on past usage of DERCs. After discussions with EPA, 
TCEQ committed to adopt and submit as a SIP revision, additional 
regulations prior to the 2009 ozone season that will limit the usage of 
DERCs by facilities in the DFW NAA. TCEQ plans to propose a DERC usage 
limitation such that 17.2 tpd of the 20.4 tpd currently in the 2009 
modeling, will not be allowed to be used in 2009. The TCEQ submitted a 
commitment to EPA to adopt and submit to EPA as a SIP revision, an 
enforceable mechanism by March 1, 2009 that would limit DERC usage to a 
maximum daily usage of 3.2 tpd of NOX DERCs effective March 
1, 2009. Texas also committed to adopt and submit as a SIP revision, an 
enforceable mechanism that would provide a review procedure to ensure 
that future allowable use of DERCs after January 1, 2010, would not 
interfere with continued attainment of the 8-hour NAAQS. We have 
concluded that an enforceable mechanism, as described in more detail 
elsewhere in this notice, can provide the basis for revising the 
quantity of DERCs that were modeled in the May 30, 2007 SIP submittal.
    In the May 30, 2007 SIP submittal, TCEQ also included requirements 
on the operation of back-up generators with a March 1, 2009 compliance 
date that had been estimated as potentially generating 0.9 tpd of 
NOX reductions in the DFW NAA. TCEQ quantified and discussed 
these rules in the WOE section of the SIP rather than including the 
estimated emission reductions in their modeling. The April 23, 2008 
letter, includes an estimate of the reduction of ozone that would occur 
based on the 0.9 tpd of NOX reduction.
    In its letter, TCEQ provided estimates of the predicted impact on 
modeled ozone that would occur due to the changes in emission 
projections for airports, DERCs and back-up generators. TCEQ based 
these estimates on sensitivity runs of the model, which showed the 
model's response to various levels of ``across-the-board'' reductions 
for various emissions categories. These runs differ from more refined 
modeling because emissions reductions are not assigned to the 
particular grid cell where they are expected to occur.
    EPA considers the use of modeling sensitivity runs, based on the 
adjustments to the Combo 10 modeling and similar sensitivity runs, to 
estimate the revised modeling FDV projections to be acceptable in these 
limited circumstances. In this case, the EPA's modeling sensitivity 
runs using the future control strategies modeling run, indicate the 
modeling is reacting very linearly over this limited range. Therefore, 
estimating changes to ozone levels due to limited emission changes to 
the 2009 emissions inventory will yield results similar to what would 
be predicted if there were a new refined future control strategies 
modeling run using a 2009 emissions inventory reflecting the revised 
emissions for the airport, DERCs, and back-up generators. Additionally, 
our analysis is that these modeling sensitivity runs are similar in 
spatial allocation to how these emission changes for the airports, 
DERCs, and back-up generators would be analyzed in a new future control 
strategies model run using a revised 2009 emissions inventory. EPA 
therefore finds the use of modeling sensitivities runs, based on the 
adjustments to the Combo 10 modeling and similar sensitivity runs, is 
acceptable in this fact-specific instance, to estimate the revised 
modeling FDV projections. Therefore, EPA considers these adjustments to 
modeled ozone levels to be refinements to the previous modeling 
(submitted in the May 30, 2007, SIP) that would have been included in 
TCEQ's original submittal if additional time would have been available 
to incorporate the changes. EPA has reviewed these three revisions to 
the emissions inventories and TCEQ's projection of their impact on the 
future ozone concentration levels and finds that TCEQ provided a 
reasonable assessment of projected ozone levels. In fact we believe, 
particularly in the case of the airport emissions adjustment, that if 
these reductions had been modeled specifically rather than spread 
across the off road mobile emissions category, there would have been 
greater ozone reduction benefit because of the location of these 
emissions when compared to the location of the highest monitors. A more 
detailed discussion of our analysis is contained in the MOAAD TSD. 
Relying on these modeling-based estimates presumes that Texas will 
adopt an enforceable measure that will limit the use of DERCs to 3.2 
tpd.
    Table 3 lists the estimated level of ozone when the adjustments to 
airport, DERC and back-up generator emissions are considered.

                                                        Table 3.--Adjusted Modeling Projections.
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                DERC       Airport       Backup
                                                                             emissions    emissions    generators                   FDV          FDV
                     Monitor                       FDV combo     FDV PDMR  ---------------------------------------    Total       adjusted     adjusted
                                                       10          2009      (17.2 tpd    (9.39 tpd     (0.9 tpd    reduction     combo 10    PDMR 2009
                                                                              reduced)     reduced)     reduced)
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                     TCEQ RRF     TCEQ RRF     DERC ppb  Airport ppb     B.G. ppb          ppb     TCEQ RRF     TCEQ RRF
--------------------------------------------------------------------------------------------------------------------------------------------------------
Frisco..........................................         88.7         89.0        -0.39        -0.32        -0.03        -0.74           87           88
Dallas Hinton...................................         85.6         85.8        -0.36        -0.26        -0.02        -0.64           84           85
Dallas North....................................         84.8         85.1        -0.36        -0.28        -0.03        -0.66           84           84
Dallas Exec.....................................         78.8         79.0        -0.47        -0.19        -0.02        -0.68           78           78
Denton..........................................         88.6         88.8        -0.32        -0.43        -0.04        -0.79           87           88
Midlothian......................................         83.9         84.1        -0.66        -0.09        -0.01        -0.75           83           83
Arlington.......................................         80.9         81.0        -0.67        -0.24        -0.02        -0.94           79           80
Ft Worth C13....................................         85.6         85.7        -0.57        -0.34        -0.03        -0.95           84           84
Ft Worth C17....................................         84.8         85.0        -0.37        -0.43        -0.04        -0.85           84           84
--------------------------------------------------------------------------------------------------------------------------------------------------------


[[Page 40214]]

    With the addition of these new reductions included in the April 23, 
2008, letter, Combo 10 projects using TCEQ's RRF that 7 of 9 are in 
attainment (at or below 84 ppb); and projections for the other two 
monitors are 87 ppb for the Denton and Frisco monitors. EPA believes it 
is reasonable to consider the above values as a sufficient 
representation of outputs of refined future year control strategy runs. 
Thus EPA considers the modeling values estimated in Table 3 to 
represent the final attainment demonstration modeling analysis.
ix. What Are EPA's Conclusions of the Modeling Demonstration?
    Using the TCEQ's RRF method and Combo 10 run with the three 
refinements, both the Frisco and Denton monitors are at 87 ppb and the 
rest of the monitors are projected to be attaining the standard. EPA 
also considered EPA's RRF method and determined that while the EPA 
method gives slightly higher results in some cases, it does not make a 
significant difference. In addition, EPA concludes that the modeling 
provided results that are in the range (82 ppb to <88 ppb) where it is 
recommended other WOE be considered to determine if attainment will be 
reached.
    Although the modeled attainment test is not met at all of the DFW 
monitors, EPA recognizes that models are approximations of complex 
phenomena. The modeling analyses used to demonstrate that various 
emission reduction measures will help to bring the DFW area into 
attainment of the 1997 8-hour ozone standard, contain many elements 
that are uncertain (e.g., emission projections, meteorological inputs, 
model response, simplified chemistry, simplified temporal and spatial 
allocation of emissions, etc.). These uncertain aspects of the DFW 
analyses can prevent definitive assessments of future attainment 
status. The confidence in the accuracy of the quantitative results from 
a modeled attainment test should be a function of the degree to which 
the uncertainties in the analysis were minimized. However, while 
Eulerian air quality models represent the best tools for integrating 
emissions and meteorological information with atmospheric chemistry and 
no single additional analysis can replace that, EPA believes that all 
attainment demonstrations are strengthened by additional analyses that 
help confirm whether the planned emissions reductions will result in 
attainment of the standard.
    EPA's modeling guidance indicates that when the maximum attainment 
demonstration modeling projections are within the 82 to less than 88 
ppb range, further WOE analyses should be included in the attainment 
demonstration and evaluated in addition to the modeling projections. 
EPA's guidance also allows for WOE to be used when the modeled levels 
are 88 ppb or greater, but notes the further the projected levels are 
from attainment levels, the more substantial the WOE must be to 
conclude that the area would reach attainment by the attainment date. 
EPA's 2005 and 2007 A.D. guidance documents indicate that even though 
the photochemical modeling demonstration projections do not predict 
attainment of the standard (the modeled attainment test), assessment of 
a WOE analysis could yield a determination that the area will attain 
the standard by its attainment date. The next section will discuss the 
WOE that has been evaluated for this demonstration and EPA's review of 
the WOE.
b. What Weight of Evidence Has Been Evaluated?
    Both EPA's 2005 and 2007 A.D. guidance documents recommend that in 
addition to a modeling demonstration, the states include additional 
analyses, called weight-of-evidence (WOE) when the modeling results in 
FDVs are greater than 82 ppb. EPA's 2005 and 2007 A.D. guidance 
documents both discuss additional relevant information that may be 
considered as WOE. A WOE analysis may provide additional scientific 
analyses as to whether the proposed control strategy, although not 
modeling attainment, will likely achieve attainment by the attainment 
date. The intent of EPA's guidance is to utilize the WOE analysis to 
consider potential uncertainty in the modeling system and future year 
projections. Thus, in the DFW case, even though the specific control 
strategy modeling predicts some monitors to be above the NAAQS, 
additional information (WOE) may provide a basis to conclude monitored 
attainment may be achieved. Since the attainment year is just a year 
away, EPA places greater significance on the WOE, especially 
consideration of current measured ozone levels and reductions still 
expected. As models have to make numerous simplifying assumptions and 
when the system being modeled is very complex, model predictions are 
not perfect. As a result of some of these inherent uncertainties, EPA's 
guidance is to consider other evidence (WOE) to help assess whether 
attainment of the NAAQS is likely. EPA's guidance indicates that 
several items should be included in a WOE analyses, including the 
following: Additional modeling, additional reductions not modeled, 
recent emissions and monitoring trends, known uncertainties in the 
modeling and/or emission projections, and other pertinent scientific 
evaluations. Pursuant to EPA's guidance, TCEQ supplemented the control 
strategy modeling with WOE analyses.
    Today we are discussing the more significant components of the WOE 
that impacted EPA's evaluation of the attainment demonstration. Many 
other elements are discussed in the MOAAD TSD that had some impact on 
EPA's evaluation. We are briefly covering the more significant elements 
in this notice. For EPA's complete evaluation of the WOE considered for 
this notice, see the MOAAD TSD.
i. What Additional Modeling-Based Evidence Did Texas Provide?
    Texas submitted a significant body of information as WOE in the May 
30, 2007, submittal. Texas also provided supplemental information and 
clarifications in a letter to EPA dated April 23, 2008.
1. Texas Emission Reduction Plan (TERP)
    TERP reductions for previous years was included in a previous SIP 
revision, the Increment of Progress (IOP) SIP and included in the 
modeled projections. Texas provided information in its May 30, 2007, 
submission and the April 23, 2008, letter documenting that additional 
reductions from the TERP Program (in 2008 and 2009) which were not 
included in the modeling are projected to occur. The impact of these 
reductions can be estimated in the WOE analysis.
    The additional TERP funding is expected to produce air quality 
benefits above-and-beyond those modeled for the SIP. The modeling 
includes reductions expected for TERP through 2007. Not all of the 
reductions were accounted for and this shortfall must be achieved 
before additional WOE reductions can be achieved. As additional WOE, 
TCEQ estimated that 14.2 tpd reductions in NOX emissions in 
the DFW area could be achieved, if 50 percent of available 2008 funding 
and 70 percent of the 2009 funding were used for projects in the DFW 
area. This calculation is based upon funding for the DFW area at $53 
million in FY2008 and $94 million in FY2009, an average seven-year 
project life with 250 days/year utilization, an estimated $6,000 cost 
per ton for TERP program emissions reductions, and using 2008 funds 
remaining after the short-fall is met ($6000/ton x 250 days/year x 7 
years life cycle = $10.5 million for 1 tpd

[[Page 40215]]

of NOX reductions). As of April 2008, requests in 2008 for 
TERP projects in the DFW area totaled $94.5 million. Therefore, once an 
estimated $39 million of project requests is utilized to fill the 
previous shortfall, there is an additional $55.5 million of project 
requests in the DFW area for further NOX reductions. These 
project requests will be reviewed by TCEQ to determine whether the 
projects are cost effective and TCEQ will make determinations about 
funding of the projects that pass review. Pending TCEQ's review and 
granting decisions, the surplus DFW area FY2008 new project requests 
(estimated surplus of $55.5 million in requests that are estimated to 
yield 5.25 tpd in NOX reductions) seem to be in line with 
the calculated project requests needed to achieve a 14.2 tpd reduction 
in NOX emissions if another $94 million (estimated to yield 
8.95 tpd in NOX reductions) in requests are received by TCEQ 
in FY2009.
    It should be noted that the $94 million in requests that was 
received in FY2008 is much larger than any previous annual request in 
the DFW area.
2. Compressor Engines
    In the April 23, 2008, letter, TCEQ provided supplemental 
information regarding emissions from stationary, gas-fired engines. 
During the May 23, 2007, adoption agenda before the TCEQ commissioners 
for the 30 TAC Chapter 117 rules and DFW 1997 8-hour ozone attainment 
demonstration SIP, stakeholders commented that the number of 
stationary, gas-fired engines in the DFW area was likely underestimated 
in the modeling projections because of the growing exploration and 
production of natural gas from the Barnett Shale. The commissioners 
directed the TCEQ's staff to research the issue. TCEQ staff 
subsequently conducted a survey to re-evaluate the number of 
stationary, gas-fired engines in the nine-county DFW area. The 2007 
TCEQ survey results show there is a much larger fleet of stationary, 
gas-fired internal combustion engines than estimated in the SIP 
submittal. Almost all of these engines came into service after the 1999 
base year so represent emissions growth. This growth in emissions will 
be greatly mitigated by the implementation of controls in response to 
the Chapter 117 rules adopted as part of the May 30, 2007, SIP 
submission. While mitigated to a large extent, emissions in the model 
from these sources would be expected to be 3.3 tpd higher than the 
model projected. Using previously discussed modeling sensitivity runs, 
we account for this increase in projected emissions and estimate its 
effect on modeled ozone levels in Table 4.
    Table 4 includes the estimates for the amount of ozone reductions 
for these additional TERP and Compressor Engines WOE emission changes. 
Table 5 is included below and includes the estimated FDVs with 
consideration of the two adjustments.

            Table 4.--Assessment of Additional WOE Emission Reductions and Potential Ozone Reductions
----------------------------------------------------------------------------------------------------------------
                                                                    TERP using     NG compressor   Total change
                                                                      nonroad      engines using ---------------
                                                                    sensitivity       nonroad
                     Monitor                        EPA nonroad  ----------------   sensitivity
                                                    sensitivity                  ---------------- Net tpd  -10.9
                                                                   tpd reduction   tpd increase
                                                                       -14.2            3.3
----------------------------------------------------------------------------------------------------------------
                                                         ppb/ton      ppb change      ppb change  Net ppb change
----------------------------------------------------------------------------------------------------------------
Frisco..........................................        -0.03387         -0.4810           0.112           -0.37
Dallas Hinton C60...............................        -0.03060         -0.4345           0.101           -0.33
Dallas North C63................................        -0.02866         -0.4070           0.095           -0.31
Dallas Exec C402................................        -0.02455         -0.3487           0.081           -0.27
Denton..........................................        -0.05343         -0.7587           0.176           -0.58
Midlothian......................................        -0.01332         -0.1891           0.044           -0.15
Arlington.......................................        -0.02868         -0.4072           0.095           -0.31
Ft Worth C13....................................        -0.03347         -0.4753           0.110           -0.36
Ft Worth C17....................................        -0.04906         -0.6967           0.162           -0.53
----------------------------------------------------------------------------------------------------------------

    As shown in Table 5, using the TCEQ RRF method for both the Combo 
10 and PDMR2009 runs with the three modeling refinements and also these 
modeling-based WOE adjustments, the Frisco and Denton monitors are 87 
ppb and the rest of the monitors are projected to be attaining the 
standard. Other WOE factors, discussed below, indicate further progress 
that we believe will lead to attainment of the standard.

                       Table 5.--Modeling-Based Assessment With Some WOE Elements Included
----------------------------------------------------------------------------------------------------------------
                                                                  Total modeling-      FDV with WOE emission
                                                                     based WOE      estimates w/ modeling-based
                                                                     reduction     ozone adjustments applied to
                                                                 ----------------  previously adjusted modeling
             Monitor               FDV adjusted    FDV adjusted                               values
                                     combo 10        PDMR2009                    -------------------------------
                                                                        ppb                          Adjusted
                                                                                  Adjusted combo   PDMR2009  w/
                                                                                     10  w/WOE          WOE
----------------------------------------------------------------------------------------------------------------
                                        TCEQ RRF        TCEQ RRF        TCEQ RRF        TCEQ RRF        TCEQ RRF
----------------------------------------------------------------------------------------------------------------
Frisco..........................            87.9            88.2           -0.37              87              87
Dallas Hinton...................            84.9            85.2           -0.33              84              84

[[Page 40216]]

 
Dallas North....................            84.1            84.4           -0.31              83              84
Dallas Exec.....................            78.1            78.3           -0.27              77              78
Denton..........................            87.8            88.0           -0.58              87              87
Midlothian......................            83.2            83.4           -0.15              83              83
Arlington.......................            79.9            80.1           -0.31              79              79
Ft Worth C13....................            84.6            84.8           -0.36              84              84
Ft Worth C17....................            84.0            84.2           -0.53              83              83
----------------------------------------------------------------------------------------------------------------

ii. Other Non-Modeling WOE From TCEQ
    EPA believes that, with only one year left until attainment, it is 
important to look at the current air quality and the amount of 
reductions that are yet to occur to evaluate whether it is realistic 
that the area can attain by 2009.
    The preliminary highest value for the 4th high 8-hour exceedance 
value monitored at any monitor in the DFW NAA in 2007 was 89 ppb. (The 
value is considered preliminary because TCEQ has not certified that it 
has completed the Quality Assurance and Quality Control Checks, a 
process that will be completed shortly). This is the lowest level that 
has ever been achieved for the fourth high in this area.
    In the May 30, 2007 submittal, TCEQ also provided additional WOE of 
ozone trends that show the area had monitored attainment for the 1-hour 
ozone standard (now revoked). The data indicates emission trends and 8-
hour ozone levels have decreased despite large population increases. As 
included in references in TCEQ's TSD for this SIP revision, TCEQ and 
others have also provided ozone source apportionment assessments 
showing that DFW emissions can contribute up to approximately 40% of 
the ozone exceedance values projected by the model at monitors downwind 
of DFW on high ozone days, while the episode average of all monitors 
was 24%. Ozone source apportionment techniques are tools used to 
estimate the contribution of various sources or source categories to 
modeled ozone levels. In this case, source apportionment is showing 
that ozone levels on some days during the episode are much more heavily 
influenced by emissions within the nonattainment area which are the 
primary target of the control strategy. The attainment test relies on a 
relative response factor which is an average value that is based on 
most of the days of the episode. The response of the RRF to local 
controls would be expected to be consistent with 24% of the ozone level 
being driven by local emissions since both the RRF and 24% source 
apportionment are averaged across the episode. However, on specific 
days when a monitor is more directly impacted by DFW area emissions 
(downwind of the core DFW area) the ozone value reflected at the 
monitor may be 40% due to local DFW NAA emissions. Therefore, the 
attainment test with the averaging of days with different wind 
directions is likely under-estimating the benefit of local reductions 
in the DFW NAA.
    TCEQ also submitted WOE components that are further discussed in 
the TSD including the following: Ozone design value trends, ozone 
variability analysis and trends, model projected RRFs at area monitors 
that have been installed since the base case period and were not 
utilized in the modeling, NOX and VOC monitoring trends, 
emission trends, NOX and VOC chemistry limitation analysis, 
local contribution analyses, and mobile emission sensitivity runs. 
Details of these WOE components are included in Chapter 3 of the May 
30, 2007 SIP submittal. TCEQ also provided updated data for some of 
these elements in their April 23, 2008 letter.
    Additional quantified WOE emissions reductions (without ozone 
reductions calculated) include a number of energy efficiency measures 
(Residential and Commercial Building Codes, municipality purchase of 
renewable energies, political subdivision projects, electric utility 
sponsored programs, Federal facilities EE/RE Projects, etc.) that TCEQ 
has estimated will yield 2.12 tpd NOX reductions.
III. EPA WOE Analysis
    Since the May 30, 2007 submittal, EPA has worked with TCEQ to 
quantify emission reductions that will occur between the latest ozone 
monitoring season (2007) and the attainment year 2009. EPA has 
generated an estimate of how much reduction in emissions is expected to 
occur between 2007 and 2009. Our estimate is that an additional 70 tpd 
of NOX reductions will occur due to the existing rules. With 
the inclusion of all of the potential WOE reduction elements (including 
14.2 tpd of NOX reductions from TERP and additional 
estimated reductions of 35.7 tpd from control of the underestimated 
compressor engines) the total potential reductions are estimated as 120 
tpd of NOX. Based on an estimated 2007 NOX 
emission inventory, these SIP rules (and other State and Federal 
requirements) are estimated to reduce NOX emissions 15% from 
2007 levels. With inclusion of all the potential WOE elements 
identified, the amount of reduction of daily NOX from 2007 
levels increases to 26%. These are large expected changes to the DFW 
NAA NOX inventory.
    Utilizing multiple sensitivity runs conducted by EPA and TCEQ, we 
have estimated that the additional 15% reductions which occur after the 
2007 ozone season could result in a 2.3 ppb decrease in ozone levels at 
the controlling monitors (Frisco and Denton). EPA's assessment, 
including both the SIP and WOE emission reductions estimated to occur 
after the 2007 ozone season, indicates a 3-4 ppb drop in ozone levels 
is possible. The 3-4 ppb drop is a rough estimate that could be larger 
(greater than 4 ppb) and that value would yield a value of 84 ppb or 
lower to indicate attainment.

[[Page 40217]]

    The monitored attainment test is monitor specific and in the future 
the highest monitor that is used to determine attainment (using 2007-
2009 data) may not be the one that recorded a high value of 89 ppb in 
2007. Only 2 of the 20 monitors in the DFW area monitored 4th high 8-
hour values of 89 ppb. The 4th high 8-hour ozone levels monitored at 
the other 18 monitors were: 88 ppb at one monitor, 87 ppb at one 
monitor and the rest were 84 ppb or below. If the monitor used for the 
2009 attainment test is one of the monitors that recorded a value less 
than 89 ppb (18 of the 20 monitors), then a 3-4 ppb drop from the 4th 
high value recorded in 2007 would indicate attainment with a value of 
84 ppb or lower. With the emission reductions to occur after 2007, we 
could expect a 4th high value for the DFW area of approximately 84-85 
ppb or lower. Based on this analysis, it is not unreasonable to 
conclude that attainment in 2009 is possible considering the recent 
downward monitoring trend (2006-2007) and the preliminary 2007 
monitoring values of 89 ppb value.
    This simplistic analysis alone does not conclusively prove that the 
area will attain the standard by 2009, but EPA believes that the most 
recent preliminary monitoring values from 2007, coupled with the 
estimated impact of the additional reductions, estimated ozone 
decreases (estimated as 3-4 ppb), are consistent with reaching 
attainment by 2009.
1. EPA Meteorological Adjusted Trends Analysis
    EPA performed a draft meteorological adjusted trends analysis in 
October 2007 for many areas in the eastern half of the United States. 
Meteorological adjusted trends analyses attempt to remove the 
variability in ozone levels due to differing meteorology and adjust the 
ozone values to the average meteorology level. These analyses are 
called met adjusted design values and can be used to indicate whether 
nonattainment areas are closer to (or farther from) attainment than 
their actual most recent design values would otherwise indicate. The 
technique and estimated values should not be used in an absolute sense, 
but rather as a directional assessment tool.
    EPA performed a meteorological adjusted analysis for select DFW 
monitors with higher DVs for the last 10 years of data (where 
available). The most recent DFW NAA DV (based on preliminary monitoring 
data for 2007) is 95 ppb (2005-2007). EPA's meteorological adjusted 
trends analysis yields a value of 91.7 ppb for the 2005-2007 period. 
Thus, the analysis indicates that the 2005-2007 period was worse than 
normal meteorology. So if average meteorology occurs in the future, the 
DV may potentially drop on the order of 3 ppb without consideration of 
additional emission reductions. The met adjusted trends analysis also 
included an assessment of the years around the 1999 base period of the 
modeling. The assessment of the base period indicated that the 
meteorology was worse than normal, and when this is taken into account, 
the highest Base DVs would be about 0.8 ppb lower. If the 
meteorological adjusted Base DV is used for the modeling projection, 
the 2009 modeling values would be approximately 0.8 ppb less, thus the 
2009 modeling would be closer to attainment. If this 0.8 ppb level 
decrease is used for the Frisco and Denton monitors, the future 
modeling and WOE projection would also drop. The resultant estimates 
would be that Combo 10 would yield 86 ppb at the Denton and Frisco 
monitors, and for the PDMR2009 modeling the values would be 87 ppb at 
Frisco and 86 ppb at Denton monitor.
iv. Other WOE Items From Texas Not Currently Quantified: Additional 
Programs/Reductions
    These are additional items in TCEQ's WOE analysis that are not 
easily quantifiable and are difficult to estimate expected ozone 
decreases. These elements can still add to the overall WOE analysis but 
may not warrant as much emphasis as more refined technical analyses.
1. AirCheckTexas
    The AirCheckTexas (ACT) program provides funds to individuals as an 
incentive to retire older, more polluting vehicles or aid in the repair 
of vehicles' emission control systems. TCEQ included discussion of the 
ACT program in the WOE section in their May 30, 2007 submittal, but did 
not include a benefit due to the ACT program in the modeling.
    The May 30, 2007 submittal also states that the Texas Legislature 
was considering additional funding for the ACT--Drive a Clean Machine 
program. During the 80th Legislative Session, Senate Bill 12 was passed 
and subsequently signed by the Governor on June 15, 2007. The ACT 
program for the DFW area was funded at $21,348,583 each for fiscal 
years 2008 and 2009. Currently the program funding has been increased 
to approximately $20 million/year for two years in DFW NAA. The 
Legislature significantly increased the amount paid for replacement of 
vehicles older than 10 years old (or vehicles that have failed emission 
testing and can't be reasonably fixed) to $3,000 for a new/recent model 
year vehicle and $3500 for a hybrid vehicle. Promotion of this program 
has been unprecedented and recently the State and local agencies have 
received and processed applications for the $20 million allotted to DFW 
area this year, well in advance of the State fiscal year end date of 
August 31st.
    The North Central Texas Council of Governments (NCTCOG) is the 
local entity implementing the program and processing applications. 
Since the SB 12 enhanced program started on December 12, 2007, there 
has been high interest and 15,092 applications submitted. Again, 
outreach by TCEQ, NCTCOG, local business leaders, and local governments 
has been unprecedented, and recently the NCTCOG indicated that there 
were 6,986 vouchers issued by April 4, 2008. With the level of voucher 
issuance and usage, it is likely the program will result in emission 
reductions greater than considered in the WOE portion of the May 30, 
2007 SIP submittal.
    Other unquantified WOE emissions reductions include Luminant's 
(formerly TXU) announcement that they are going to spend $1 billion to 
yield emission reductions at some of their plants in East and North 
Central Texas. Luminant has initially indicated that their plans 
include installing SCR at the Martin Lake plant, SNCR at Monticello and 
Big Brown plants and improving their Low NOX burners at one 
of the Monticello units. We sent a letter to Luminant asking for 
clarification on what NOX controls may be in place by the 
2009 DFW ozone season, and are currently waiting for a response from 
Luminant. If we receive a response from Luminant, we will include it in 
the docket for review. These facilities are to the East and Southeast 
of the DFW area, and are often upwind of DFW during ozone events. 
Reductions at these plants will help lower background ozone and pre-
cursor entering DFW area on many ozone conducive days and would be 
expected to yield reductions in ozone levels at the DFW area monitors 
on many ozone conducive days.
2. Local Quantified and Unquantified Measures
    Other unquantified measures include Dallas Sustainable Skylines 
Initiative, Smartway, Intelligent Transportation System, Truck Lane 
Restriction, LED Traffic Signal replacement, Blue Skyways 
Collaborative, Parking Cash-out Program, Roadway Peak Period Pricing, 
Clean School Bus Program, $4

[[Page 40218]]

million incentive for early NG engine control, etc. These programs are 
not included in the VMEP program and therefore are not being double-
counted.
    Through the actions of citizens and local governments, an approach 
to purchase cement that is produced with less NOX emissions 
is being considered by local cities. Currently three of the largest 
cities (Dallas, Ft. Worth, and Arlington) have passed city ordinances 
addressing the purchase of green cement. These ordinances may yield an 
additional 1 tpd of NOX reductions, but this estimate is not 
certain at this time. We expect additional reductions will be achieved 
and that the location of the reductions would be beneficial to reducing 
the area's ozone levels.
    Local city and county officials have increased their enforcement of 
Inspection and Maintenance (I&M) rules by performing site inspections. 
In certain cases, officials discovered fraudulent transactions, 
including inspection sticker counterfeiting. The enforcement 
initiatives by local governments will result in additional emission 
reductions from mobile sources in the DFW area. Some of these benefits 
are already considered in the modeling, but these efforts will yield 
additional actual reductions between 2007 and 2009.
c. Is the 8-Hour Attainment Demonstration Approvable?
    EPA is proposing that, taken in balance, the available modeling, 
evidence, analyses, adopted control strategies (including rules with 
2010 compliance dates), the DERCs condition, monitoring data, and 
additional information support that the DFW area will reach attainment 
of the 1997 8-hour ozone standard by its attainment date. In making 
this determination, we have considered supplemental information not 
available at the time the attainment modeling was performed by TCEQ, 
including evidence that NOX emissions reductions will occur 
that are in addition to the measures adopted and quantified in the May 
30, 2007 SIP submittal.
    We have considered modeling using two emission reduction scenarios 
(Combo 10 and PDMR2009), recognizing that the actual emission control 
level would be somewhere in between. We have also considered the impact 
of additional measures and reductions documented in the April 23, 2008 
letter. With these adjustments, the modeling is showing significant 
reductions of 7-13 ppb in ozone from the base period, but is still 
slightly short of attainment. The modeling predicts values greater than 
84 ppb at two of the nine monitors, but we believe the WOE assists in 
bridging the gap to attainment.
    We also considered that the model's under prediction of high ozone 
levels may be biasing the model predictions, and therefore potentially 
underestimating the ozone reduction that could occur by the emission 
reductions achieved by local and regional rules and additional WOE 
elements. We also have considered the impact of meteorological 
adjustments to the design value projection which would further indicate 
the future projections may be too high. Finally, we have recognized 
emission reduction efforts that have not been quantified and included 
in the modeling or model based WOE estimates.
    EPA is also considering non-modeling evidence. One factor that EPA 
believes is of particular importance is the total NOX 
reductions expected in the DFW NAA from 2007 to 2009, which are 
expected to decrease ozone levels from the 89 ppb fourth high maximum 
monitored in 2007 to levels consistent with attainment. We have 
confidence that ozone levels will improve because NOX 
emissions are projected to decrease by 26% in the time period 2007-
2009. Finally, EPA has considered the most recent ambient data which 
indicates that the area is on a track that is consistent with achieving 
attainment of the 8-hour standard by 2009.
    Taking these factors together, we believe the modeling, including 
all the WOE measures, is consistent with attainment.

C. Control Measures Relied Upon by the State in the Control Strategy 
Modeling

    Section 172 of the Act provides the general requirements for 
nonattainment plans. Section 172(c)(6) and section 110 require SIPs to 
include enforceable emissions limitations, and such other control 
measures, means or techniques as well as schedules and timetables for 
compliance, as may be necessary to provide for attainment by the 
applicable attainment date. The DFW attainment demonstration SIP is 
mainly directed at reductions of NOX since the modeling 
shows that NOX reductions will be most effective in bringing 
the area into attainment of the standard, but the SIP includes VOC 
emissions reductions as well. The modeling includes Federal, State and 
local measures. The attainment demonstration modeling also relies on 
regional measures applied in east and central Texas and measures 
applied in the Houston (HG) and Beaumont (BPA) ozone nonattainment 
areas. The State adopted controls to reduce NOX emissions 
from mobile sources, ICI Sources, EGFs, Minor Sources, Cement Kilns, 
and East Texas Combustion Sources. Today's action proposes approval of 
emissions reductions from two mobile source strategies not previously 
adopted into the SIP. These strategies are the new VMEP and the new 
TCMs included in the May 30, 2007 SIP submittal. In separate actions, 
we are finalizing approval of the April 9, 2003 Alcoa Federal Consent 
Decree, the Energy Efficiencies Program, and the May 13, 2005, 
NOX rules, and we are proposing to approve the 
NOX rules for ICI Sources,EGFs, Minor Sources, Cement Kilns, 
and East Texas Combustion Sources. These actions will assist the area 
in meeting the 8-hour ozone standard and are relied upon in the control 
strategy modeling.
    The following is the identification of the control measures 
reflected in the 2009 inventory for the May 30, 2007 revision Future 
Control Strategy Case modeling run. In addition, we identify which of 
the State and local controls are addressed in this proposed action and 
which will be addressed in separate rulemaking actions.

     Table 6.--Federal Measures Reflected in the DFW 2009 Inventory
------------------------------------------------------------------------
 
-------------------------------------------------------------------------
Federal Tier 1 Federal Motor Vehicle Control Program (FMVCP)
Federal Tier 2 FMVCP
Federal 2007 Heavy Duty Diesel FMVCP standards
Federal National Low Emission Vehicle Program (NLEV)
Federal Tier I and Tier II Locomotive NOX standards
Federal New Non-road Spark Ignition Engines rule
Federal Heavy Duty Non-road Diesel Engines rule
Federal Tier 1, 2, and 3 Non-road Diesel Engines rule
Federal Small Non-road Spark Ignition Engines rule
Federal Large Non-road Spark Ignition Engines and Recreational Marine
 rule
Non-road RFG--Federal/state opt in--the 4 core counties
------------------------------------------------------------------------

    We believe that the State correctly projected the growth rates and 
emissions reductions for sources subject to these Federal measures.

[[Page 40219]]



      Table 7.--State Measures Reflected in the DFW 2009 Inventory
------------------------------------------------------------------------
                Measures                              Status
------------------------------------------------------------------------
DFW gas-fired engine rule..............  EPA is taking action in a
                                          separate rule.
DFW non-EGUs--banked ERCs and DERCs for  Approved September 6, 2006 (71
 VOC and NOX emissions.                   FR 52703).
DFW EGUs...............................  EPA is taking action in a
                                          separate rule.
DFW non-EGUs...........................  EPA is taking action in a
                                          separate rule.
Auxiliary steam boilers in the 5         EPA is taking action in a
 counties.                                separate rule.
Stationary gas turbines in the 5         EPA is taking action in a
 counties.                                separate rule.
DFW Major Source Rule..................  EPA is taking action in a
                                          separate rule.
DFW Minor Source Rule..................  EPA is taking action in a
                                          separate rule.
Stage I Program, expanded from the 4     Approved January 19, 2006 (71
 core to all 9 counties.                  FR 3009).
Surface Coating Rules, expanded from     Approved January 19, 2006 (71
 the 4 core to all 9 counties.            FR 3009).
Inspection/Maintenance (I/M) Program,    Approved November 14, 2001 (66
 expanded from the 4 core to all 9        FR 57261).
 counties.
Anti-tampering Rule....................  Approved July 1, 1998 (63 FR
                                          35839).
RFG in the 4 core counties.............  Approved October 8, 1992 (57 FR
                                          46316).
VOC Rules, expanded from the 4 core to   EPA is taking action in a
 all 9 counties, adopted by TCEQ on 11/   separate rule.
 15/06.
Portable Fuel Container Rule...........  Approved February 10, 2005 (70
                                          FR 7041).
Reid Vapor Pressure Rule...............  Approved April 26, 2001 (66 FR
                                          20927).
------------------------------------------------------------------------

    We believe that the State correctly projected the growth rates and 
emissions reductions for sources subject to these State measures.

      Table 8.--Local Measures Reflected in the DFW 2009 Inventory
------------------------------------------------------------------------
                Measures                              Status
------------------------------------------------------------------------
VMEP...................................  Proposed for approval in this
                                          action.
TERP...................................  Program already approved; SIP
                                          credits proposed for approval
                                          in this action.
TCMs...................................  Proposed for approval in this
                                          action.
Energy Efficiencies Program (EEP)......  EPA is taking action in a
                                          separate rule.
Speed Limits...........................  Approved October 11, 2005 (70
                                          FR 58978).
------------------------------------------------------------------------

    We believe that the State correctly projected the growth rates and 
emissions reductions for sources subject to these local measures.

  Table 9.--Texas Regional Measures Reflected in the DFW 2009 Inventory
------------------------------------------------------------------------
                Measures                              Status
------------------------------------------------------------------------
Agreed Orders for Alcoa and Texas        Approved October 26, 2000 (65
 Eastman.                                 FR 64148).
East Texas Chapter 117 NOX requirements  Approved March 16, 2001 (66 FR
                                          15195).
East Texas Combustion Rule.............  EPA is taking action in a
                                          separate rule.
April 9, 2003 Alcoa Federal Consent      EPA is taking action in a
 Decree.                                  separate rule.
TxLED (includes locomotives)...........  Approved November 14, 2001 (66
                                          FR 57196).
Portable Fuel Container Rule (34         Approved February 10, 2005 (70
 counties).                               FR 7041).
Stage I................................  Approved December 20, 2000 (65
                                          FR 79745).
Lower RVP..............................  Approved April 26, 2001 (66 FR
                                          20927).
Cement kiln rules......................  EPA taking action in a separate
                                          rule.
------------------------------------------------------------------------

    We believe that the State correctly projected the growth rates and 
emissions reductions for sources subject to these Regional measures.

   Table 10.--Houston (HG) and Beaumont (BPA) Ozone Nonattainment Area
              Measures Reflected in the DFW 2009 Inventory
------------------------------------------------------------------------
                Measures                              Status
------------------------------------------------------------------------
Chapter 117 NOX requirements for HG....  Approved November 14, 2001 (66
                                          FR 57230).
Chapter 117 NOX requirements for BPA...  Approved 26, 2000 (65 FR
                                          64158); September 9, 2000 (65
                                          FR 53172); and March 3, 2000
                                          (65 FR 11468).
HG MECT rule for HG EGUs...............  Approved September 6, 2006 (71
                                          FR 52664).
HG non-EGUs--banked ERCs and DERCs for   Approved September 6, 2006 (71
 VOC and NOX emissions and the MECT NOX   FR 52664).
 cap.
HG highly-reactive VOC cap (HRVOC) rule  Approved September 6, 2006 (71
                                          FR 52659).

[[Page 40220]]

 
BPA non-EGUs--banked ERCs and DERCs for  Approved March 16, 2001 (66 FR
 VOC and NOX emissions.                   15195).
Agreed Orders for Premcor, Exxon         Approved April 12, 2005 (70 FR
 Chemical, and Motiva in the BPA Ozone    18995).
 SIP.
------------------------------------------------------------------------

    We believe that the State correctly projected the growth rates and 
emissions reductions for sources subject to these measures in the HG 
and BPA ozone nonattainment areas.

D. Local Measures Relied Upon in the Control Strategy Modeling

    Today's action proposes approval of two new emission reductions 
from local strategies not previously adopted into the SIP. These 
strategies are the VMEP and TCMs. These controls should assist the area 
in meeting the 8-hour ozone standard. Approval of the relied-upon 
control measures must be finalized before EPA takes final action 
approving the attainment demonstration SIP.
 a. Voluntary Mobile Source Emission Reduction Programs
    A voluntary mobile source emissions reductions program (VMEP) is an 
overall control strategy that attempts to complement existing 
regulatory programs through voluntary, non-regulatory changes in local 
transportation activities or changes in in-use vehicle and engine 
composition. Authority for our approval of the VMEP is primarily 
grounded in section 110(a)(2) of the Act, as well as sections 
182(g)(4)(A) and 108. Section 110(a)(2) establishes that a SIP must 
include ``enforceable emissions limits and other control measures, 
means or techniques * * * as well as schedules and timetables for 
compliance, as may be necessary or appropriate to meet the applicable 
requirements of this chapter.''
    In interpreting 110(a)(2) of the Act, EPA issued a guidance 
document entitled, ``Guidance on Incorporating Voluntary Mobile Source 
Emission Reduction Programs in State Implementation Plans (SIPs),'' 
Memorandum from Richard D. Wilson, Acting Assistant Administrator for 
Air and Radiation, dated October 24, 1997, which allows for SIP credit 
for voluntary measures. The Fifth Circuit Court of Appeals upheld, as a 
reasonable interpretation of the Act, EPA's VMEP policy and allowed the 
State to consider estimated emissions reductions from a VMEP in the 
Houston area 1-hour ozone attainment demonstration. See BCCA Appeal 
Group v. EPA, 355 F.3d 817, 825 (5th Cir. 2003).
    The EPA's VMEP Guidance provides a detailed framework for states to 
obtain SIP emissions reduction credit for such voluntary emissions 
reductions. EPA guidance allows VMEP to provide a maximum of 3% of the 
total future year emissions reductions required to attain the 
appropriate NAAQS. In addition, states must identify and describe the 
voluntary measures in a VMEP and include supportable projections of 
emissions reductions associated with the measures. The state must also 
make an enforceable commitment to monitor, assess, and report on the 
implementation and emissions effects of the VMEPs, as well as to remedy 
timely any shortfall in emissions reductions that do not meet the 
projected levels.
    The EPA guidance sets forth specific minimum criteria for approval 
of VMEPs into the SIP. The criteria specify that VMEP emissions 
reductions be quantifiable, surplus, enforceable, permanent, and 
adequately supported. The state must promptly assess and backfill any 
shortfall pursuant to enforceable commitments in the SIP in the event 
that the projected emission reductions are not achieved. In addition, 
VMEPs must be consistent with attainment of the standard and with the 
RFP requirements and must not interfere with other requirements of the 
Act.
    The NCTCOG, as the regional metropolitan transportation planning 
agency for the DFW area, has committed to implement the projects and/or 
programs outlined in the DFW VMEP submittal. The estimated benefits 
listed are calculated for the year 2009. The NCTCOG will be responsible 
for monitoring and reporting the emissions reductions to the TCEQ. The 
NCTCOG, through TCEQ, will cover any VMEP shortfall (of the total 2.63 
tpd of NOX committed) by supplementing additional 
Transportation Emission Reduction Measures (TERMs). The program areas 
that may be used to remedy a shortfall are traffic signal improvements; 
intelligent transportation systems (ITS); and/or freeway and/or 
arterial bottleneck removal. Texas submitted adequate program 
descriptions that project emissions reductions attributable to each 
specific voluntary program and included the basis for the quantified 
emissions reductions. The DFW VMEP will be implemented in each of the 
nine counties within the DFW area.
    NCTCOG identified seven voluntary programs that will aid in the 
improvement of the DFW area's air quality, as described below. Table 11 
lists the programs and projected credits:

   Table 11.--Voluntary Mobile Emission Reduction Programs and Credits
                                 Claimed
------------------------------------------------------------------------
          Program type             2009 NOX benefits   2009 VOC benefits
------------------------------------------------------------------------
Clean Vehicle Program...........                0.24                0.05
Employee Trip Reduction.........                0.43                0.28
Locally Enforced Idling                         0.62                0.02
 Restriction....................
Diesel Freight Idling Reduction                 0.33                0.01
 Program........................
SmartWay Transport Demonstration                0.00                0.00
 Project........................
Public Agency Policy for                        0.06                0.01
 Construction Equipment.........
Aviation Efficiencies...........                0.95                0.24
                                 ---------------------------------------
    Total Benefits..............                2.63                0.61
------------------------------------------------------------------------


[[Page 40221]]

    As stated above, the State commits to evaluating each program to 
validate estimated credits, to evaluating and reporting on the program 
implementation and results, and to promptly remedy any credit 
shortfall. The State also commits to additional TERMs that can be 
substituted for any shortfall in credit from the estimated credits for 
VMEP. These include traffic signal improvements, ITS; and/or freeway 
and/or arterial bottleneck removal.
    EPA's analysis of all the VMEP measures shows that each creditable 
measure is quantifiable. All VMEP measures must be in place by March 1, 
2009, in order to be relied on for purposes of attainment by June 15, 
2010. The emissions benefits for the measures are calculated for 2009 
and are permanent as the NCTCOG is responsible to monitor, assess, 
report on future emissions reductions from the measures and remedy any 
shortfall. The reductions are surplus by not being substitutes for 
mandatory, required emissions reductions and are not being counted in 
any other control strategy. The SIP with voluntary measures is 
enforceable because the State has committed to fill any shortfall in 
credit, thus any enforcement will be against the State. Each measure is 
adequately supported by personnel and program resources for 
implementation. The State's goal is 2.63 tpd of NOX benefit 
from the VMEP. Our detailed evaluation of the State's VMEP is in the 
TSD.
    The DFW VMEP meets the criteria for credit in the SIP. The State 
has shown that the credits are quantifiable, surplus, enforceable, 
permanent, adequately supported, and consistent with the SIP and the 
Act. We propose to approve the VMEP into the DFW SIP and agree with the 
projected NOX emissions reductions of 2.63 tpd and the 
projected VOC emissions reductions of 0.61 tpd from the VMEP.
 b. Transportation Control Measures (TCMs)
    TCMs are transportation related projects or activities designed to 
reduce on-road mobile source emissions. Section 108 of the Act outlines 
allowable types of TCMs. Federal regulations at 40 CFR 93.101 define a 
TCM as any measure that is specifically identified and committed to in 
the applicable implementation plan that is either one of the types 
listed in section 108 of the Act, or any other measure for the purposes 
of reducing emissions or concentrations of air pollutants from 
transportation sources by reducing vehicle use or changing traffic flow 
or congestion conditions.
    Nonattainment areas may submit TCMs as air quality control measures 
into the SIP. TCMs used as an emissions reductions control strategy 
must be specific and enforceable as required by the Act and EPA 
guidance. TCMs in the SIP must include an identification of each 
project, location, length of each project (if applicable), a brief 
project description, implementation date, and emissions reductions for 
NOX and VOC. (See ``Transportation Control Measures: State 
Implementation Plan Guidance,'' September 1990 (EPA 450/2-89-020)).
    The process for TCM selection and inclusion in the SIP is based on 
consideration of all potential measures specified in section 108 of the 
Act and other emerging transportation control measures that may be 
reasonably available for implementation and used for emissions 
reductions. The TCMs identified through this process and included in 
the SIP are contained and funded in the region's metropolitan 
transportation plan and Transportation Improvement Program. This 
ensures that the TCMs were properly adopted, funded and received 
appropriate approval. Inclusion of TCMs in the SIP also shows evidence 
of a specific schedule to plan, implement and enforce the measures. EPA 
approved the Texas TCM rule as a revision to the SIP on December 5, 
2002 (67 FR 72379).
    The NCTCOG identified in Appendix F of the SIP submittal TCMs for 
use as a control strategy for attainment of the ozone NAAQS. Appendix F 
of the submittal lists seven categories of TCMs: bicycle-pedestrian 
projects; grade separation projects; high-occupancy vehicle/managed 
lane projects; intersection improvement projects; park and ride 
projects; rail transit projects; and vanpool projects. The TCMs have 
been, or will be, implemented in the nine-county DFW area. By the start 
of the 2009 ozone season, the TCMs should reduce NOX 
emissions in the DFW area by 1.53 tpd and VOC emissions by 1.61 tpd.
    The State has shown that the DFW TCMs meet the requirements of the 
Act and applicable EPA guidance. The list of TCMs provided in Appendix 
F of the State's submittal provides identification of each project, 
location, length of each project (if applicable), a brief project 
description, completion/implementation date, and emissions reductions 
for NOX and VOCs. EPA's detailed evaluation of the 
approvability of the State's TCMs can be found in the TSD to this 
action. EPA agrees that the implementation of TCMs will reduce 
NOX emissions in the DFW area by 1.53 tpd and VOC emissions 
by 1.61 tpd. We therefore propose to approve the State's TCMs into the 
DFW SIP.
c. Measures Discussed in the April 23, 2008 Letter From TCEQ
    Texas provided a letter on April 23, 2008 supplementing the 
information in the May 2007 SIP. Below we discuss two of the issues 
raised in the letter (TERP and DERCs) in detail as these have 
significantly impacted our review of the modeling and weight of 
evidence as discussed in section V-B.
i. Texas Emission Reduction Plan (TERP)
    TERP is a discretionary economic incentive program (EIP) providing 
economic incentives to reduce emissions. Although TERP is composed of 
several different components, the part of the plan that EPA approved 
into the Texas SIP is the diesel emission reduction program. See 66 FR 
57160 (November 14, 2001). The approved TERP program is a grant 
program, unique to Texas, that provides funds through TCEQ in a variety 
of categories, including emissions reduction incentive grants, rebate 
grants (including grants for small businesses), and heavy and light 
duty motor vehicle purchase or lease programs, all with the goal of 
improving air quality in Texas. Examples of TERP programs include 
assisting small businesses in purchasing lower-emission diesel 
vehicles, helping school districts to reduce emissions from school 
buses, and providing funds to support research and development of 
pollution-reducing technology. TERP is available to all public and 
private fleet operators that operate qualifying equipment in any of the 
ozone nonattainment counties within the State, including the nine that 
comprise the DFW area.
    State rules that govern TCEQ administration of TERP were approved 
into the SIP on August 19, 2005, at 70 FR 48647. The State's previous 
methodologies for determining emissions reductions from this type of 
program have been found acceptable by EPA.
    Texas twice submitted TERP estimated emission reductions within the 
DFW area for approval into the DFW SIP. The first submission, on May 
13, 2005, has not previously been approved into the SIP as SIP credit, 
but DFW has received air quality benefits from the emissions reductions 
achieved. This first plan submitted calculations based upon legislative 
funding that projected NOX emissions reductions of 22.2 tpd 
from TERP, which would be achieved by June 15, 2007. To date however, 
the State has shown that only 18.45 tpd of

[[Page 40222]]

the calculated 22.2 tpd NOX emissions reductions have 
occurred, leaving a shortfall of 3.75 tpd.\4\ As explained below, this 
shortfall of 3.75 tpd TERP SIP credit will be addressed and corrected 
by March 1, 2009.
---------------------------------------------------------------------------

    \4\ The shortfall was the result of an error in calculations.
---------------------------------------------------------------------------

    The second plan, submitted on April 23, 2008, projected 
NOX emissions reductions of 14.2 tpd from TERP, which would 
be achieved by March 1, 2009. The amount of TERP credit allocated to 
DFW is predicated on the funding formula set up by the Texas 
Legislature. For the 2008/2009 biennium, the Texas Legislature fully 
funded TERP in the amount of $297,144,243. TCEQ will award these TERP 
grants based on program criteria \5\ and it is possible to project 
NOX emissions reductions to occur by March 1, 2009, by using 
an estimated funding allotment for the DFW area. For example, if 50% of 
the available 2008 funds and 70% of the 2009 funds are used for 
projects in DFW, the 3.75 tpd shortfall noted above will be corrected, 
and an additional 14.2 tpd reduction in NOX emissions can be 
expected.\6\
---------------------------------------------------------------------------

    \5\ Rather than allocating funds among a subset of eligible 
(nonattainment) counties, the State will allocate based on the cost 
effectiveness of each project.
    \6\ FY08 TERP funds total approximately $146 million and nearly 
$40 million went to rebate grants, a 3rd party grant and unfunded 
FY07 applications, leaving approximately $106 million for FY08. As 
of May 22, 2008, the DFW area implemented TERP projects totaling 
18.45 tpd, but the May 13, 2005 submission projected 22.2 tpd (22.2-
18.45 = 3.75). Assuming $6,000/ton, 250 days/yr and 7 yr project 
life, it will cost approx. $39,375,000 to correct the May 13, 2005 
submission TERP deficiency (6,000 x 250 x 7) x 3.75 = 39,375,000. 
The applications submitted to TCEQ for projects in DFW for FY08 were 
approximately $94.5 million. Subtract the May 13, 2005 submission 
shortfall ($94,500,000-$39,375,000) and we are left with 
approximately $55,125,000. Divide by the (6,000 x 250 x 7) to 
estimate tons reduced by projects for the applications submitted 
($55,125,000/10,500,000 = 5.25 tpd for the FY08 applications. Of the 
projected 14.2 tpd: 14.2-5.25 = 8.95 tpd, (6,000 x 250 x 7) x 8.95 = 
$93,975,000. Thus, the DFW goal for project applications for FY09 is 
approximately $93,975,000.
---------------------------------------------------------------------------

    The emissions reductions projected for the 2008/2009 TERP are 
quantifiable, as they are projected to reduce NOX by 14.2 
tpd by March 1, 2009.\7\ This measure is surplus, as it will be used to 
fund projects that are not otherwise required under the Act or the 
Federally-approved SIP. The measure is permanent, because the average 
project life extends beyond the period in which it is used in the 
applicable SIP demonstration. TERP is fully funded by the Texas 
Legislature and has a history of adequate personnel and resources to 
implement the program. The TCEQ is obligated to monitor, assess and 
report on the implementation of TERP to the Texas Legislature. Annual 
reports document, by area, the total number of tons reduced, tons 
reduced per year, average cost per ton, grant recipients and type of 
project funded. During the first grant cycle for 2008, which spanned 
January through April, TCEQ received applications for the DFW area 
requesting a total of approximately $94.5 million, which exceeds the 
2008 target projected in the April 23, 2008 supplemental letter (see 
the docket) and is unprecedented for the DFW area.
---------------------------------------------------------------------------

    \7\ TCEQ cannot award funds for the FY2009 applications prior to 
September 1, 2008, but the grant application process could begin 
prior to that date.
---------------------------------------------------------------------------

    Projected reductions are calculated based on ``cost per ton'' of 
previous projects. The cost cited by the TCEQ and used in this 
estimation is $6,000/ton. Historically, TERP has provided 
NOX reductions in DFW with costs averaging less than $4500/
ton, and the most recent average costs are under $4000/ton. We have 
reviewed the information submitted to us (including TCEQ's April 2, 
2008 TERP summary), and we agree with the State's cost per ton 
analysis. We believe that the assumptions used to project emissions 
reductions from the TERP are conservative, and reasonable for achieving 
improvements in air quality.
    Projects funded by TERP in the DFW area will reduce NOX 
emissions by March 1, 2009, and will contribute toward attainment of 
the 8-hour ozone NAAQS by the area's attainment date. We are proposing 
to approve that the TERP program will achieve NOX emissions 
reductions of 22.2 tpd and 14.2 tpd, based on the May 13, 2005 and the 
April 23, 2008 submittals combined.
ii. Discrete Emission Credits (DECs)
    A DEC represents one ton of certified emissions reductions 
generated over a discrete time period. DECs can be generated by 
discrete reductions in criteria pollutants, with the exception of lead, 
from stationary, area or mobile sources statewide. When a stationary or 
area source generates a DEC it is known as a discrete emission 
reduction credit (DERC); when a mobile source generates a DEC it is 
known as a mobile discrete emission reduction credit (MDERC). The use 
of the term ``DERC'' collectively refers to DERCs and MDERCs unless 
specifically stated as only applying to stationary DECs. Once certified 
by the TCEQ, a DERC can either be banked for future use or used by a 
source for a variety of uses, including to exceed allowable permit 
limits, and to meet SIP requirements under 30 TAC Chapters 114, 115, 
and 117. The authority to generate and use DERCs within Texas is found 
at 30 TAC Chapter 101, Subchapter H, Division 4--Discrete Emission 
Credit Banking and Trading (the DERC rule). EPA granted final 
conditional approval of the Texas DERC rule on September 6, 2006 (71 FR 
52703).\8\
---------------------------------------------------------------------------

    \8\ TCEQ submitted revisions to the DERC rule as a SIP revision 
on October 24, 2006. The revisions included the changes to address 
our conditional approval and other revisions identified in Texas 
Senate Bill 784. EPA is currently evaluating whether the SIP 
revision satisfies the conditional approval commitments.
---------------------------------------------------------------------------

    Since the use of DERCs will increase emissions in an area, the DFW 
attainment demonstration must account for the possibility that all 
DERCs will be used in the nonattainment area (See section 12.5(d) of 
EPA Guidance entitled ``Improving Air Quality with Economic Incentive 
Programs,'' EPA-452/R-01-001, January 2001 (Economic Incentive Program 
(EIP) Guidance)). The TCEQ Emissions Bank currently has 20.4 tpd of DFW 
NOX DERCs. The DFW attainment demonstration photochemical 
modeling accounted for the possibility that all 20.4 tpd credits would 
be used in the attainment year. Section 16.15 of EPA's EIP Guidance 
provides that States may use an alternative to predicting that all 
DERCs will be used in the attainment year by establishing an 
enforceable mechanism to restrict the use of banked emission reductions 
to ensure attainment goals. TCEQ determined that restricting the use of 
DERCs to no more than 3.2 tpd would provide for attainment and be 
consistent with the flexibility of the DERC program. In a letter dated 
April 23, 2008, TCEQ provided economic and photochemical sensitivity 
analyses supportive of this enforceable mechanism.
    Our proposed approval of the 8-hour DFW SIP is conditioned on the 
TCEQ submitting a complete SIP revision that provides a 3.2 tpd 
restriction on the amount of DERCs available for use in DFW beginning 
March 1, 2009. The SIP revision may provide that the amount of DERCs 
available for use beginning January 1, 2010, could increase above 3.2 
tpd if the revision provides an enforceable mechanism and a 
justification that the increase is consistent with attainment and 
maintenance of the 1997 8-hour ozone standard. In a letter dated June 
13, 2008, TCEQ committed to adopting these conditions. Specifically, 
the TCEQ committed to submitting a SIP revision for the DERC rule that 
adopts the necessary enforceable mechanism no later than March 1, 2009. 
If Texas intends to allow for more than 3.2 tpd of DERCs to be used 
beginning January

[[Page 40223]]

1, 2010, then the SIP revision must also provide appropriate limits on 
the use of DERCs and a detailed justification explaining how the future 
adjustments to the allowed DERC usage will be consistent with continued 
attainment of the 8-hour ozone standard. The justification must provide 
sufficient detail such that the public can be assured that attainment 
will continue to be projected in future years. The justification and 
methodology for any increase in allowable DERC usage must be fully 
identified in the TCEQ rulemaking and SIP submittal process.
    The SIP revision submitted by March 1, 2009, must adequately 
provide for continued attainment, and include the justification and/or 
methodology used by TCEQ to increase the amount of DERCs allowed for 
use in DFW starting in calendar year 2010. The justification provided 
by TCEQ must satisfy section 110(l) of the Act and demonstrate that the 
increase will not interfere with attainment or any other applicable 
measure of the Act. The analysis to satisfy section 110(l) will need to 
address both quantity and spatial allocation impacts of increased DERC 
usage on ozone levels.
    We will also consider whether TCEQ restricted allowable DERC usage 
to 3.2 tpd consistent with the attainment demonstration for the year 
2009. The DERC rule enables the TCEQ Executive Director (ED) to approve 
Notice of Intent to Use Forms up to 90 days prior to the use period. 
Therefore, it is possible that the ED could approve the use of DERCs 
for a time period including March 1, 2009 and any time thereafter, 
before the 3.2 tpd restriction has been adopted by the TCEQ and 
submitted as a SIP revision. At the time EPA takes final action on the 
proposed conditional approval, EPA will review all Notice of Intent to 
Use Forms that have been approved for use in 2009 to ensure that the 
total amount of DERCs approved for use beginning on March 1, 2009 does 
not exceed 3.2 tpd.

E. Reasonably Available Control Measures (RACM)

    The RACM requirement applies to all nonattainment areas that are 
required to submit an attainment demonstration. Section 172(c)(1) of 
the Act requires SIPs to provide for the implementation of all RACM as 
expeditiously as practicable and for attainment of the standard. EPA 
interpreted the RACM requirements of 172(c)(1) in the General Preamble 
to the Act's 1990 Amendments (April 16, 1992, 57 FR 13498) as imposing 
a duty on States to consider all available control measures and to 
adopt and implement such measures as are reasonably available for 
implementation in the particular nonattainment area. EPA also issued a 
memorandum reaffirming its position on this topic, ``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, dated 
November 30, 1999. In addition, measures available for implementation 
in the nonattainment area that could not be implemented on a schedule 
that would advance the attainment date in the area would not be 
considered by EPA as reasonable to require for implementation. EPA 
indicated that a State could reject certain measures as not reasonably 
available for various reasons related to local conditions. A state 
could include area-specific reasons for rejecting a measure as RACM, 
such as the measure would not advance the attainment date, or was not 
technologically and economically feasible. Although EPA encourages 
areas to implement available RACM measures as potentially cost-
effective methods to achieve emissions reductions in the short term, 
EPA does not believe that section 172(c)(1) requires implementation of 
potential RACM measures that either require costly implementation 
efforts or produce relatively small emissions reductions that will not 
be sufficient to allow the area to achieve attainment in advance of 
full implementation of all other required measures.
    The TCEQ provided the DFW RACM analysis in Appendices K, L and M of 
the SIP submittal. Texas evaluated control strategies for 
NOX and VOC emissions, from area, point and mobile (on-road 
and non-road) sources. The candidate strategies were identified by 
reviewing documents published by multi-state air planning 
organizations, EPA documents, and proposed and approved control 
strategies for nonattainment areas in other states (see list in the 
TSD). As discussed in Chapters 2 and 3 of the SIP submittal, 
sensitivity analyses and the photochemical modeling indicate that DFW 
ozone is more responsive to NOX reductions than VOC 
reductions. Based upon the analyses and modeling, only large reductions 
of VOC emissions, over 100 tpd, would advance the attainment date in 
DFW. We were unable to identify any additional available evaluated 
measures that cumulatively would provide 100 tpd in VOC emissions 
reductions and thus, advance the attainment date for the DFW area. Many 
measures to reduce VOCs are already in place, through state and Federal 
mobile source programs and rules to reformulate solvents, including the 
recently published Federal rules for Architectural and Industrial 
Coatings (73 FR 15604, March 24, 2008), which Texas estimates could 
reduce VOC emissions in the DFW area by 12.5 tpd. On November 15, 2006, 
TCEQ extended the VOC RACT requirements to include all nine counties in 
the DFW area; we are acting on these measures in a separate rulemaking, 
though in Section VI we are evaluating whether these rules implement 
RACT. Our analysis showed that the State already is controlling the 
significant VOC stationary and mobile sources to RACM levels in the 
specific DFW area. For more detail, see the TSD.
    The majority of NOX emissions in the DFW area come from 
mobile sources and industrial processes; emissions of NOX 
have been reduced to a large extent with controls on EGUs and improved 
mobile source programs. Our evaluation of Texas' modeling analyses 
found that NOX reductions of at least 40 tpd would be needed 
to advance the attainment date by one year. This is because at least 40 
tpd of reductions will occur in the last year of the plan. We were 
unable to identify any additional evaluated measures that cumulatively 
would provide 40 tpd in NOX emissions reductions and thus, 
potentially advance the attainment date for the DFW area. Many 
NOX control measures are already in place in the nine 
counties and in the eastern half of Texas. Texas extended the 
NOX RACT requirements to include all of the nine counties. 
Texas adopted new NOX control measures for ICI Sources 
(brick, ceramic and lime kilns; glass melting furnaces, etc); EGFs; 
Cement Kilns; and Stationary Internal Combustion (IC) Engines (gas-
fired, diesel and dual-fuel) in the nine counties. Texas also adopted 
new NOX control measures for East Texas Combustion Sources 
located outside of the DFW area.
    We also reviewed whether there were any additional available 
evaluated strategies to reduce NOX emissions from mobile 
sources. Our analysis showed that the State SIP has in place TCMs, 
VMEP, TERP, ACT and a motor vehicle I/M program. Several of the 
measures on the State's list are already covered under the TCMs, VMEP, 
TERP and ACT programs and several other measures are being implemented 
by various cities within the DFW area. Our analysis showed that the 
State is controlling the significant NOX stationary and 
mobile sources to RACM levels.
    The State estimated that NOX emissions reductions of 
approximately 23 tpd from point sources and

[[Page 40224]]

approximately 20 tpd from fleet turnover will be in place in the DFW 
area by March 1, 2009. Given the control strategies already in place 
for the DFW area, any additional available measures would not advance 
attainment. Moreover, we note that in order to advance attainment by a 
year (i.e., by June 15, 2009), the State would have had to implement 
any additional control measures needed for attainment by the beginning 
of the 2008 ozone season, which has already passed. Thus, at this time, 
it would be impossible to implement additional controls that would 
advance attainment. EPA has reviewed the RACM analysis provided in the 
SIP submittal for the DFW area and believes that the State has included 
sufficient documentation concerning the rejection of certain available 
measures as RACM for the DFW area.
    We propose that any other available evaluated measures are not 
reasonably available for the DFW area, because they are either 
economically and/or technically infeasible, or would not produce 
emissions reductions sufficient to advance the attainment date in the 
DFW area and, therefore, should not be considered RACM. For more 
information, see the TSD.

F. Failure-to-Attain Contingency Measures Plan

    Section 172(c)(9) of the Act requires nonattainment SIPs to provide 
for a contingency plan that will take effect without further action by 
the State or EPA if an area fails to attain the standard by the 
applicable date. While the Act does not specify the type of measures or 
quantity of emissions reductions required, EPA provided guidance on 
contingency plans in the General Preamble (57 FR 13498, 13510). See the 
TSD for a list of applicable guidance documents.
    EPA interprets sections 172 and 182 of the Act to require States 
with moderate or above ozone nonattainment areas to include contingency 
measures to implement additional emission reductions of 3% of the 
adjusted base year inventory in the year following the year in which 
the failure has been identified. EPA based the 3% recommendation in the 
General Preamble on the fact that moderate and above areas are 
generally required through the ROP/RFP requirements to achieve an 
average of 3% reduction per year until they attain the NAAQS. The state 
must specify the type of contingency measures, the quantity of 
emissions reductions, and show that the measures can be implemented 
with no further rulemaking and minimal further action by the state.
    For the failure-to-attain 1997 8-hour ozone contingency measures 
plan, Texas identified contingency measures that were adopted for the 
1-hour ozone standard but never implemented. The contingency measures 
include State VOC rules approved by EPA in the Texas SIP for Offset 
Lithographic Printing at 30 TAC 115.449(c) (approved April 6, 2000, 65 
FR 18003, revised July 16, 2001, 66 FR 36917), Degassing or Cleaning of 
Stationary, Marine, and Transport Vessels at section 115.549(b) 
(approved January 26, 1999, 64 FR 03841, revised February 27, 2008, 73 
FR 10380) and Petroleum Dry Cleaning at section 115.559(a) (approved 
January 26, 1999, 64 FR 03841, revised February 27, 2008, 73 FR 10383). 
Our review of the May 30, 2007 SIP revision indicates that the failure-
to-attain 1997 8-hour ozone contingency measures plan does not identify 
sufficient measures to achieve additional emissions reductions of 3% of 
the emissions in the adjusted 1999 base year emissions inventory, as 
required by our interpretation of the Act (see EPA's General Preamble 
at 57 FR 13498, 13510). Rather, the identified controls would only 
achieve 0.35% reduction.
    Texas provided a commitment letter, which identifies contingency 
measures that the State will recommend for adoption through rulemaking 
and has committed to submit to EPA no later than March 1, 2009 as a SIP 
revision (see letter of June 13, 2008, in the docket) adopted rules 
that could achieve the additional reduction, providing a total of 3%, 
for the failure-to-attain contingency measure plan. The commitment 
letter states that Texas will adopt and submit no later than March 1, 
2009 to EPA as a SIP revision, subject to the SIP public participation 
requirements and commission approval, a revised failure-to-attain 1997 
8-hour ozone contingency measures plan that would include the Federal 
Motor Vehicle Control programs (FMVCP) occurring after the 2009 ozone 
season, in addition to the already-identified VOC rules described 
above. The FMVCP requires controls on both on- and non-road motor 
vehicles, providing emissions reductions as the fleet is replaced with 
newer vehicles (turns over). Texas' April 23, 2008 letter estimates 
projected emissions reductions attributed to this 2009-2010 fleet 
turnover from mobile sources occurring after the 2009 ozone season to 
be approximately 20.78 tpd of NOX and 4.86 tpd of VOCs. The 
emissions inventory from this attainment demonstration SIP submittal, 
which uses 1999 as the base year, estimates emissions from 
anthropogenic sources are 754.56 tpd NOX and 520.08 tpd VOC. 
Texas projects the 2009-2010 fleet turnover reductions alone will 
provide a 2.75% reduction of NOX and a 0.93% reduction of 
VOC from the 1999 base year emissions. Texas also estimates that the 
contingency measures identified in the May 30, 2007 submittal provide a 
cumulative total of 1.8 tpd VOC reductions.
    We have reviewed the May 30, 2007, SIP revision and the State's 
commitment and determined that the VOC and fleet turnover control 
measures identified are specific and that the VOC measures are 
enforceable because they are approved into the SIP and will become 
effective if the area fails to attain the standard by the applicable 
date. We have determined that the quantity of emissions reductions 
exceeds 3% of the 1999 base year emissions inventory based upon Texas' 
estimate that the 2009-2010 fleet turnover reductions will provide a 
2.75% reduction of NOX and a 0.93% reduction of VOC from the 
1999 inventory. We agree with the State's projected emissions 
reductions. We believe Federal measures already scheduled for 
implementation and not relied upon in the attainment demonstration are 
appropriate contingency measures (Phase 2 Rule, 70 FR 71612, 71651).
    Therefore, we are proposing that the contingency measures 
identified in the SIP submittal and in the State's commitment letter 
would meet Federal requirements for a 1997 8-hour ozone failure-to-
attain contingency measures plan. We are proposing to approve the 1997 
8-hour ozone failure-to-attain contingency measures plan for the DFW 
area, contingent upon the State's adoption of and submittal to EPA, of 
a new failure-to-attain contingency measures plan that includes the 
above-described VOC rules and the additional described control measure, 
fleet turnover from mobile sources after the 2009 ozone season. If 
Texas submits a revised failure-to-attain 1997 8-hour ozone contingency 
measures plan that includes the specifically identified measures, i.e., 
the VOC rules and fleet turnover after 2009 from mobile sources, we 
will move forward with a final full approval of the 1997 8-hour ozone 
failure-to-attain contingency measure SIP for the DFW area. Any 
comments concerning whether these four measures are sufficient to meet 
the failure-to-attain contingency measure requirement should be raised 
at this time. EPA does not plan to provide an additional opportunity 
for comment unless the State modifies these measures or submits a 
failure-to-attain contingency

[[Page 40225]]

measures plan relying on other measures. Because the failure-to-attain 
contingency measure SIP is a necessary component of the attainment 
demonstration, if Texas fails to submit such a SIP revision, we cannot 
move forward with a final conditional approval action on the DFW 1997 
8-hour ozone attainment demonstration SIP, as we have also proposed in 
this notice.

G. Attainment Motor Vehicle Emission Budgets (MVEBs)

    The 1997 8-hour ozone attainment demonstration SIP must include 
MVEBs for transportation conformity purposes. Conformity to a SIP means 
that transportation activities will not produce new air quality 
violations, worsen existing violations, or delay timely attainment of 
the NAAQS. It is a process required by section 176(c) of the Act for 
ensuring that the effects of emissions from all on-road sources are 
consistent with attainment of the standard. EPA's transportation 
conformity rules at 40 CFR 93 require that transportation plans and 
related projects result in emissions that do not exceed the MVEB 
established in the SIP. The attainment year established in the DFW 1997 
8-hour ozone attainment demonstration SIP is the calendar year of the 
final ozone season for determining attainment, which is 2009. See 40 
CFR 93.118(b).
    The attainment MVEB is the level of total allowable on-road 
emissions established by the control strategy implementation plan. 
Ozone attainment demonstrations must include the estimates of motor 
vehicle VOC and NOX emissions that are consistent with 
attainment, which then act as a budget or ceiling for the purposes of 
determining whether transportation plans, programs, and projects 
conform to the attainment demonstration SIP. In this case, the 
attainment MVEBs set the maximum level of on-road emissions that can be 
produced in 2009, when considered with emissions from all other 
sources, which demonstrate attainment of the 1997 8-hour ozone NAAQS.
    The 2009 attainment MVEBs established by this plan and that the EPA 
is proposing to incorporate into the DFW SIP are listed in Table 12:

  Table 12.--2009 DFW Attainment Motor Vehicle Emissions Budgets (tpd)
------------------------------------------------------------------------
                         Pollutant                               2009
------------------------------------------------------------------------
NOX........................................................       186.81
VOC........................................................        99.09
------------------------------------------------------------------------

    We found the 2009 attainment MVEBs (also termed transportation 
conformity budgets) ``adequate'' and on June 28, 2007, the availability 
of these budgets was posted on EPA's Web site for the purpose of 
soliciting public comments. The comment period closed on July 30, 2007, 
and we received no comments. On March 21, 2008, we published the Notice 
of Adequacy Determination for these attainment MVEBs (73 FR 15152). 
Once determined adequate, these attainment MVEBs must be used in future 
DFW transportation conformity determinations.
    The attainment budget represents the on-road mobile source 
emissions that have been modeled for the attainment demonstration. The 
budget reflects all of the on-road control measures in that 
demonstration. We believe that the MVEBs are consistent with all 
applicable SIP requirements and thus are proposing to approve adoption 
of the 2009 attainment MVEBs into the DFW 1997 8-hour ozone attainment 
demonstration SIP. All future transportation improvement programs, 
projects and plans for the DFW area will need to show conformity to the 
budgets in this plan.

H. Section 110(l) Analysis

    Section 110(l) of the Act precludes EPA from approving a revision 
of a plan if the revision would interfere with any applicable 
requirement concerning attainment and RFP (as defined in section 171), 
or any other applicable requirement of the Act. EPA interprets section 
110(l) to allow substitution of a control measure in the SIP with a 
different control measure if the new measure will accomplish new and 
contemporaneous emissions reductions to offset the loss of the control 
measure being removed from the SIP. We also ensure that air quality 
will not degrade and that progress toward attainment will continue as 
EPA promulgates revised ozone standards.
    As of 2006, the DFW area is monitoring attainment of the 1-hour 
ozone standard (now revoked. See Phase I Rule, 69 FR 23951). Measures 
from the 2000 1-hour SIP have been approved into the SIP and remain 
enforceable, with one exception. The Texas Legislature caused the 
statewide residential water heater emission standards to be relaxed in 
2005 due to the inability of water heater manufacturers to supply units 
compliant with the rule. Therefore, the more stringent rule was never 
implemented. TCEQ requested that this measure be revised in the SIP and 
substituted with new and contemporaneous reductions of NOX 
emissions from the TERP program that were in excess of those required 
by the April 27, 2005 DFW 5% IOP SIP. EPA agrees with the State 
rationale. EPA and the State projected NOX reductions of 0.5 
tpd from the State's residential water heater rule in the DFW area. The 
reductions from the TERP program in the DFW 5% IOP SIP were projected 
to provide 22.2 tpd in NOX emissions reductions, or an 
excess of 4.23 tpd over the 5% IOP. The actual NOX emissions 
reductions achieved however, were 18.45 tpd (22.2-18.45 = 3.75 tpd). 
Even with this change in the projected emissions reductions of 
NOX in the IOP Plan, however, the projected NOX 
reductions used to make up for the revision of the residential water 
heater rule are nearly met (4.23-3.75 = 0.48). And, per the discussion 
in section III-C above, the shortfall of 0.02 tpd needed to make up for 
the revised residential water heater rule is projected to occur.
    In summary, the State adopted the water heater rule for the purpose 
of contributing to attainment of the 1-hour NAAQS. The emission 
standards in the rule were made less stringent due to technical 
infeasibility. The DFW area has monitored attainment of the 1-hour 
NAAQS. TCEQ substituted new and contemporaneous reductions of 
NOX emissions from the TERP program. In addition, Texas has 
demonstrated attainment of the 1997 8-hour NAAQS using the revised 
water heater rule. We therefore are proposing to find that the revised 
State rule for residential water heaters meets section 110(l) of the 
Act for the DFW area.

VI. Reasonably Available Control Technology (RACT)

    Sections 172(c)(1) and 182 of the Act require areas that are 
classified as moderate or above for ozone nonattainment to adopt 
Reasonably Available Control Technology (RACT) requirements for sources 
that are subject to Control Techniques Guidelines (CTGs) issued by EPA 
and for ``major sources'' of VOC and NOX, which are ozone 
precursors. See 42 U.S.C. sections 7502(c)(1) and 7511a(b) and (f). 
RACT is defined as the lowest emissions limitation that a particular 
source is capable of meeting by the application of control technology 
that is reasonably available considering technological and economic 
feasibility (44 FR 53762,

[[Page 40226]]

September 17, 1979). A CTG provides information on the available 
controls for a source category and provides a ``presumptive norm'' 
RACT. In this action, EPA is addressing RACT for VOCs in the DFW area 
for the 1997 8-hour ozone standard, and for the 1-hour standard; RACT 
for NOX in DFW will be addressed in a separate rulemaking.
    EPA published the 8-hour ozone designations and the Phase 1 Rule 
for implementing the 8-hour ozone standard and the designations for the 
8-hour ozone standard on April 30, 2004 (69 FR 23858 and 69 FR 23951, 
respectively). At the time of designation, DFW was a nonattainment area 
for the 1-hour ozone standard and had two outstanding 1-hour ozone 
obligations: (1) The area did not have an approved 1-hour ozone 
attainment demonstration; and (2) the area did not have approved RACT 
requirements for VOC emissions (VOC RACT). All other 1-hour 
requirements were approved. For additional information, see the TSD.
    According to EPA's Phase 2 Rule (70 FR 71612, November 29, 2005), 
areas classified as moderate nonattainment or higher must submit a 
demonstration, as a revision to the SIP, that their current rules 
fulfill 1997 8-hour ozone RACT requirements for all CTG categories and 
all major non-CTG sources. Since DFW is classified as moderate for the 
1997 8-hour ozone standard, for purposes of meeting the 8-hour RACT 
requirement, the DFW area must demonstrate RACT level controls for 
sources covered by a CTG document, and for each major non-CTG source 
(100 tpy or greater potential to emit). The Phase 2 Rule, section IV.G 
states, in part, that where a RACT SIP is required, State SIPs 
implementing the 8-hour standard generally must assure that RACT is 
met, either through a certification that previously required RACT 
controls represent RACT for 8-hour implementation purposes or through a 
new RACT determination. The RACT SIP submitted by TCEQ provides an 
analysis which demonstrates how the DFW area meets RACT requirements 
for the 1997 8-hour ozone NAAQS. See the TSD for more information about 
the State's VOC RACT analysis for DFW.
    In addition, the Phase 1 Rule provides that 1-hour ozone 
nonattainment areas are required to adopt and implement ``applicable 
requirements'' according to the area's classification under the 1-hour 
ozone standard (see 40 CFR 51.905(a)(i)). The DFW area was still 
classified as a serious nonattainment area at the time of the 8-hour 
designation and an outstanding ``applicable requirement'' for the DFW 
area is VOC RACT. In the four core counties, which comprised the 1-hour 
ozone nonattainment areas, Texas previously adopted rules to address 
RACT requirements for all source categories covered by EPA CTGs, and to 
address major sources at the moderate area major source threshold of 
100 tpy. The EPA approved these rules as meeting VOC RACT for a 
moderate 1-hour ozone nonattainment area (60 FR 12438). The 
reclassification of the area from moderate to serious for the 1-hour 
ozone standard, on February 18, 1998 (63 FR 8128), required Texas to 
ensure that RACT was in place on non-CTG sources down to 50 tpy. Texas 
submitted a SIP to address this requirement and we proposed to approve 
the SIP submission as meeting the 1-hour ozone serious area VOC RACT 
requirements for the DFW 1-hour ozone nonattainment area on January 18, 
2001 (66 FR 4756). Although we received no comments on that proposal, 
we never took final action.
    We are re-opening the comment period on that proposed action for 1-
hour ozone serious area RACT requirements, and intend to take final 
action on it in the same rulemaking where we finalize action on the VOC 
RACT 1997 8-hour ozone proposal. If these proposed actions are 
finalized, the DFW area will have fulfilled all of its outstanding 1-
hour ozone VOC RACT obligations, and met the 1997 8-hour ozone VOC RACT 
requirements.
    The State's submittal for the DFW area for meeting the 1997 8-hour 
ozone RACT requirement included, among other things, the following two 
components:
    (a) A list of all CTG or ACT source categories which matched those 
categories with one or more corresponding State rules which implements 
RACT and the affected sources in the nine counties,\9\ and
---------------------------------------------------------------------------

    \9\ An earlier VOC-related Texas rulemaking was adopted on 
November 15, 2006, and submitted to EPA on December 13, 2006, as a 
SIP revision, which extended VOC control requirements to facilities 
located in Ellis, Johnson, Kaufman, Parker, and Rockwall counties. 
This rulemaking subjected affected VOC sources in the five counties 
mentioned above, to the same emissions limitation, control, 
monitoring, testing, recordkeeping, and reporting requirements in 
effect in the four core counties. As a result of this action, which 
EPA is proposing to approve in a separate action, these new VOC 
control requirements will be consistent for all nine counties in the 
DFW area. Approval of VOC RACT for the DFW area is contingent upon 
final approval of this related rulemaking, which extends VOC 
controls from the four core counties to the five additional 
counties.
---------------------------------------------------------------------------

    (b) An analysis of RACT for all major sources in the nine counties 
that are not covered by a CTG or ACT and how these are controlled to 
meet RACT.
    Appendices to the SIP submittal identified the sources and the 
currently applicable controls, which EPA had previously approved as 
meeting RACT for the 1-hour standard, and included an analysis of 
whether additional RACT controls were required for both CTG and non-CTG 
sources.
    To ensure RACT was in place for all major sources, the State first 
searched its permitting database to identify all sources that emit or 
have the potential to emit at least 50 tpy of VOC in the DFW 8-hour 
ozone nonattainment area. The State then provided a list of each major 
source in a source category covered by a CTG/ACT and the State VOC RACT 
Rule applicable to such major sources. The State analyzed whether the 
existing CTG/ACT VOC RACT rules should be more stringent. Second, the 
State listed potential major sources in source categories possibly not 
covered by a CTG/ACT, and the State provided further technical analysis 
for these.
    The State's RACT SIP analysis was available for public comment 
prior to adoption by the State. EPA evaluated the following elements of 
TCEQ's VOC RACT SIP submittal for the DFW Area:
     State Rules Addressing VOC RACT Requirements for Sources 
Covered by a CTG/ACT.
     Potential Major VOC Emissions Sources possibly not covered 
by a CTG/ACT.
    A list of documents used to support our review and evaluation is 
available in the TSD.
    The State's submittal included a table of all of the CTG and ACT 
documents that have been issued by EPA and the corresponding State 
Rules, contained at 30 TAC 115, which establish RACT rules for the 
sources identified in each CTG or ACT. For two of the VOC source 
categories (shipbuilding and rubber tire manufacturing), TCEQ provided 
a negative declaration certifying that there are no sources of VOCs for 
those categories in the DFW area. Texas concluded that all other CTG 
sources currently have RACT-level controls.
    Since RACT can change over time as new technology becomes available 
or the cost of existing technology decreases, it is important that 
states review new technologies. As clarified in EPA's Phase 2 Rule, 
``States and other interested parties should consider available 
information that may supplement the CTG and ACT documents'' (70 FR 
71655). In developing this submittal, TCEQ reviewed new technologies 
and current control technologies and methodologies implemented as RACT 
in other ozone nonattainment areas. TCEQ found that

[[Page 40227]]

Texas' VOC RACT rules for CTG/ACT covered sources are consistent with 
or more stringent than the current control technologies and 
methodologies implemented in other ozone nonattainment areas, which 
were determined to fulfill RACT requirements. EPA agrees that the VOC 
controls in place for DFW meet RACT. Please see the TSD for additional 
information and analysis.
    As previously discussed, as part of addressing moderate area 1-hour 
ozone requirements, EPA approved the Texas VOC rules implementing RACT 
for all required CTG or ACT categories in the four core counties and 
for major sources emitting 100 tpy or more VOC. The State extended the 
previously approved moderate provisions to the five new nonattainment 
counties, added as part of the DFW 1997 8-hour ozone nonattainment 
area. Additionally, the State had adopted for the four core counties, 
which comprised the 1-hour nonattainment area, and we had proposed to 
approve RACT rules for all sources emitting 50 tpy or more VOC as part 
of addressing the 1-hour serious area requirements.
    For the CTG/ACT categories, based on EPA's review of the State 
submittal, we conclude that the VOC controls in place meet RACT. EPA 
finds that a negative declaration for two categories (shipbuilding and 
rubber tire manufacturing) in the DFW area is appropriate. Based on (1) 
this analysis, and (2) final approval of the rule extending the CTG VOC 
controls throughout the 9-county DFW area (see footnote 9), EPA 
believes the DFW area has met all the applicable requirements to have 
VOC RACT rules for all CTG sources.
    The State's submittal also included a list of all potential major 
sources of VOC emissions within source categories possibly not covered 
by a CTG (or ACT) in the DFW area, together with a demonstration of how 
each source was determined to fulfill RACT requirements. Given its 
classification as a moderate ozone nonattainment area, TCEQ was 
required to ensure RACT is in place for all sources that emit or have 
the potential to emit at least 100 tpy (section 182(d) of the Act). 
TCEQ looked at sources with a potential to emit as low as 50 tpy of VOC 
to ensure RACT was in place for major sources not covered by a CTG or 
ACT. The TCEQ's analysis shows how each major source meets VOC RACT 
based on currently applicable controls and why no additional RACT 
controls should be required.
    The State identified 36 potentially major sources of VOC emissions 
in the DFW area, based on the 2002 emissions inventory. Of these 36 
potential sources, 20 were determined by TCEQ to be covered by rules 
that meet RACT, and one was shut down in 2004 (please see the TSD). 
Based upon further analysis of the remaining 15 sources, the State 
determined that three of the sources were not major sources. Their 
allowable emissions are less than 100 tpy and therefore are not subject 
to the RACT requirements; these are two asphalt roofing companies and a 
brick kiln.
    Eleven of the 15 sources are major sources, but fall within a 
source category covered by the State's VOC RACT rules. One of the 11 
sources, Rock-Tenn Corporation, is subject to the State's VOC RACT 
paper coating rule. The other 10 sources are subject to the State's VOC 
RACT vent gas rule: Dartco, Chaparral Steel, Hensley Industries, Johns 
Manville International, Owens-Corning Waxahachie, Exide, Ex-Tex LaPorte 
LP, TXU Generation Co, Midlothian Energy, and Holcim. The only comment 
the State received regarding the need for additional VOC RACT controls 
was that a thermal oxidizer should be used to control VOC emissions 
from the cement kiln. However, a cost analysis of the use of thermal 
oxidizers shows the cost to be beyond RACT. Detailed cost information 
is available in the TSD. The TCEQ's analysis shows that no additional 
RACT controls are required.
    The remaining source out of the original 15 was determined to be 
major and not within a source category controlled by the State's VOC 
RACT rules: A beverage alcohol production facility (Miller Brewing). 
Most of this facility's VOC emissions are fugitive emissions due to 
product loss in the packaging area. In its RACT determination for 
Miller Brewing Co, Texas stated, ``VOC emissions are controlled per 
BACT in NSR Permit No. 3133. Additional control for RACT is not 
economically feasible'' (TCEQ Appendix J). These types of sources have 
an economic incentive to operate efficiently, in order to reduce 
leakage of product, with the result in minimization of VOC emissions. 
Therefore, EPA is proposing to find that this beverage alcohol 
production facility meets RACT.
    EPA is proposing to find that the DFW 1997 8-hour ozone 
nonattainment area SIP meets the VOC RACT requirements based on current 
applicable rules for all sources addressed by a CTG and all major non-
CTG sources. EPA proposes to approve the State's submittals 
demonstrating that the DFW area meets the VOC RACT requirements for the 
1-hour ozone standard and the 1997 8-hour ozone standard.

VII. Proposed Action

    We propose to conditionally approve the 1997 8-hour ozone 
attainment demonstration SIP revision for the DFW 1997 8-hour ozone 
nonattainment area, submitted by the State on May 30, 2007, and 
supplemented on April 23, 2008. Our proposed approval of the 8-hour DFW 
SIP is conditioned on Texas adopting and submitting to EPA prior to 
March 2009, a complete SIP revision to limit the use of DERCs, 
beginning March 1, 2009. Our proposed conditional approval is 
contingent upon Texas submitting the failure-to-attain contingency 
measures plan SIP as specified in this proposal prior to the time EPA 
takes final action on the attainment demonstration SIP. We are 
proposing to find that all RACM for VOC and NOX have been 
implemented in the DFW area. We found the attainment MVEBs to be 
adequate on March 21, 2008 (73 FR 15152) and propose to approve the 
2009 attainment MVEBs into the DFW SIP. We are proposing to approve 
into the DFW SIP the VMEP and TCMs submitted on May 30, 2007. We cannot 
finalize conditional approval of the DFW 1997 8-hour ozone attainment 
demonstration SIP unless and until (1) the State meets the contingency 
regarding the failure-to-attain contingency measure requirement as 
specified in this proposal, and (2) we have approved the DFW RFP Plan 
and all of the control strategies relied upon in the attainment 
demonstration. The control strategies are specifically listed below:
    a. The DFW area's RFP plan, associated MVEBs, and RFP contingency 
measures;
    b. The April 9, 2003, Alcoa Federal Consent Decree;
    c. The rich burn gas-fired engine rule in the 33 counties east of 
DFW;
    d. The DFW major source rule;
    e. The DFW minor source rule;
    f. The DFW gas-fired engine rule;
    g. The DFW EGUs rule;
    h. The DFW non-EGUs rule;
    i. The Auxiliary steam boilers in the 5 counties;
    j. The Stationary gas turbines rule in the 5 counties;
    k. The VOC Rules adopted on 11/15/06 by TCEQ;
    l. The DFW Energy Efficiencies Program;
    m. The Cement kiln rules;
    n. The finding that DFW is meeting RACM;
    o. The VMEP;
    p. The TCMs; and
    q. The failure-to-attain Contingency Measures Plan, revised as 
specifically described today.

[[Page 40228]]

    r. An enforceable mechanism to limit the use of DERCs, as 
specifically described today.
    We are taking action on a number of the items listed above in 
separate Federal Register actions.
    We are proposing to approve that VOC rules implemented in all nine 
counties meet the RACT requirements. These rules will result in 
emissions reductions needed to help the DFW area attain the 8-hour 
NAAQS for ozone.
    EPA is proposing to approve and conditionally approve these various 
plans in accordance with section 110 and part D of the Act and EPA's 
regulations.

VIII. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this action merely proposes to approve state law as 
meeting Federal requirements and does not impose additional 
requirements beyond those imposed by state law. For that reason, this 
action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Order 
12866 (58 FR 51735, October 4, 1993);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     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);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the Clean Air Act; and
     Does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, this rule does not have tribal implications as 
specified by Executive Order 13175 (65 FR 67249, November 9, 2000), 
because the SIP is not approved to apply in Indian country located in 
the state, and EPA notes that it will not impose substantial direct 
costs on tribal governments or preempt tribal law.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Nitrogen dioxides, Ozone, 
Reporting and recordkeeping requirements, Volatile organic compounds.

    Authority: 42 U.S.C. 7401 et seq.

    Dated: July 1, 2008.
Richard E. Greene,
Regional Administrator, Region 6.
[FR Doc. E8-15805 Filed 7-11-08; 8:45 am]
BILLING CODE 6560-50-P