Document ID: EPA-R06-OAR-2007-0524-0092
Agency: epa
Document Type: Rule
Title: TX063.92 Approval and Promulgation of Air Quality Implementation Plans: Texas; Attainment Demonstration for the Dallas/Fort Worth 1997 8-Hour
Posted Date: 2009-01-14T05:00Z

[Federal Register: January 14, 2009 (Volume 74, Number 9)]
[Rules and Regulations]               
[Page 1903-1927]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr14ja09-10]                         

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2007-0524; FRL-8758-7]

 
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: Final rule; conditional approval and full approval.

-----------------------------------------------------------------------

SUMMARY: The EPA is conditionally approving the Dallas/Fort Worth (DFW) 
1997 8-hour ozone State Implementation Plan (SIP) revisions submitted 
on May 30, 2007 and November 7, 2008, as supplemented on April 23, 
2008. This final conditional approval action is for the attainment 
demonstration SIP, which includes the 2009 attainment Motor Vehicle 
Emissions Budgets (MVEBs), the Reasonably Available Control Measures 
(RACM) demonstration, and the failure-to-attain contingency measures 
plan. The approval is conditioned upon Texas adopting and submitting to 
EPA prior to March 1, 2009, a complete SIP revision to limit the use of 
Discrete Emission Reduction Credits (DERCs), beginning in March 2009. 
If the State meets its commitment to submit the DERC SIP revision, EPA 
will undertake additional rulemaking action on the approvability of the 
DERC SIP revision and, if EPA approves that SIP revision, the 
conditional approval of the attainment demonstration will be converted 
to a full approval at that time.
    We are fully approving two local control measures relied upon in 
the attainment demonstration, the Voluntary Mobile Source Emission 
Reduction Plan (VMEP) and Transportation Control Measures (TCMs). We 
are also fully approving the DFW area SIP as meeting the Reasonably 
Available Control Technology (RACT) requirement for volatile organic 
compounds (VOCs) for both the 1-hour and 1997 8-hour ozone standards. 
These actions will result in emissions reductions in the DFW 8-hour 
ozone nonattainment area and meet section 110 and part D of the Act and 
EPA's regulations.

DATES: This final rule is effective on February 13, 2009.

ADDRESSES: EPA has established a docket for this action under Docket 
No. EPA-R06-OAR-2007-0524. All documents in the docket are listed on

[[Page 1904]]

the www.regulations.gov Web site. 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, is not placed on the Internet and will be 
publicly available only in hard copy form. Publicly available docket 
materials are available either electronically through 
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 or Mr. Bill Deese at 214-665-7253 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 paige.carrie@epa.gov.

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

Table of Contents

I. Background
II. What Action Is EPA Taking?
    A. What Is EPA Conditionally Approving in This Action?
    B. What Is EPA Fully Approving in This Action?
III. What Happens if the State Fails To Meet the Condition?
IV. What Other Elements Must Be Approved To Allow This Final 
Conditional Approval of the Attainment Demonstration SIP?
V. Comments
    A. What Comments Did EPA Receive on the July 14, 2008 Rulemaking 
for DFW?
    B. General Comments
    C. Comments on the Texas Emissions Reduction Plan (TERP)
    D. Comments on Photochemical Modeling, Weight of Evidence 
Analyses, and Assessment of Demonstration of Attainment
    E. Comments on Discrete Emission Reduction Credits (DERCs)
    F. Comments on Reasonably Available Control Measures (RACM)
    G. Comments on the Failure-to-Attain Contingency Measures Plan
    H. Comments on the Attainment Motor Vehicle Emission Budgets 
(MVEBs)
    I. Comments on the Voluntary Mobile Source Emission Reduction 
Program (VMEP)
VI. Final Action
VII. Statutory and Executive Order Reviews

I. Background

    On July 14, 2008, 73 FR 40203, EPA proposed conditional approval of 
the DFW area's 1997 8-hour ozone attainment demonstration SIP revision, 
including the attainment MVEBs, RACM demonstration, and failure-to-
attain contingency measures plan. We proposed to fully approve two 
local control measures relied upon in the attainment demonstration--the 
VMEP and TCMs. We also proposed to fully approve the DFW area SIP as 
meeting the RACT requirement for VOCs for both the 1-hour ozone 
standard and the 1997 8-hour ozone standard.
    The proposed approval of the attainment demonstration SIP is 
conditioned upon Texas adopting and submitting to EPA 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. If Texas meets the commitment to submit the DERC SIP 
revision, EPA will undertake rulemaking to determine whether to approve 
the revision and, if approved, EPA would convert the conditional 
approval of the attainment demonstration to a full approval.
    We also proposed that final conditional approval of the attainment 
demonstration SIP was contingent upon Texas submitting to EPA a 
complete and approvable SIP revision for the attainment demonstration 
SIP's failure-to-attain contingency measures plan that meets section 
172(c)(9) of the Act. EPA specifically identified in the proposal the 
elements such submission must contain. The failure-to-attain 
contingency measures plan was submitted to EPA on November 7, 2008, and 
we have determined that the plan is consistent with the elements 
established in our proposed rule (73 FR 40203) and meets section 
172(c)(9) of the Act. Because the State submitted a complete failure-
to-attain contingency measures 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, EPA can 
proceed with a final conditional approval. (See page 40205, third 
column, of the proposed action.)
    Our July 14, 2008, proposal provides a detailed description of the 
revisions and the rationale for EPA's proposed actions, together with a 
discussion of the opportunity to comment. The public comment period for 
these actions closed on August 13, 2008. See the Technical Support 
Documents (TSDs) and our proposed rulemaking at 73 FR 40203 for more 
information.

II. What Action Is EPA Taking?

A. What Is EPA Conditionally Approving in This Action?

    EPA is conditionally approving the DFW 1997 8-hour ozone attainment 
demonstration SIP and, as part of this attainment demonstration SIP, 
the 2009 attainment MVEBs, RACM demonstration, and failure-to-attain 
contingency measures plan, submitted to EPA on May 30, 2007 and 
November 7, 2008, as supplemented on April 23, 2008.
    Our conditional approval is based on our determination that, the 
modeling and weight-of-evidence show that the DFW area will attain the 
8-hour ozone standard by its attainment date, as a result of the 
control strategies relied upon in this plan. In making this 
determination, we have considered the comments that we have received on 
our proposal. We have also considered the air quality monitoring 
information gathered since the proposal, the impact of the Clean Air 
Interstate rule (CAIR) vacatur, and the progress in implementing 
control measures. As the area approaches the attainment date, recent 
monitoring data becomes more important as an indicator of potential 
success. The preliminary data from 2008 shows 18 of the 20 monitors had 
fourth highs at 84 ppb or below and only two

[[Page 1905]]

monitors were slightly above attainment levels at 85 ppb.
    With more emissions reductions to occur before the beginning of the 
2009 attainment year ozone season, we believe these data provide strong 
support that the area will attain the standard by its attainment date 
of June 2010.
    As described in the proposed rule, the condition that must be met 
for EPA to fully approve the attainment demonstration is that the TCEQ 
must adopt and submit to EPA a complete SIP revision by March 1, 2009, 
that includes an enforceable mechanism 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 meeting this condition (the letter is in 
the docket for this rulemaking).
    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 EPA and 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 by demonstrating 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.

B. What Is EPA Fully Approving in This Action?

    EPA is fully approving two local control measures relied upon in 
the attainment demonstration: The VMEP and TCMs. We are also fully 
approving the DFW area SIP as meeting the RACT requirement for VOCs for 
both the 1-hour ozone standard and the 1997 8-hour ozone standard.

III. What Happens if the State Fails To Meet the Condition?

    If Texas fails to adopt and submit to the EPA a complete DERC SIP 
revision by March 1, 2009, EPA will issue a letter to the State 
converting the conditional approval of the 1997 8-hour ozone DFW 
attainment demonstration SIP to 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 FR a notice announcing 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 Regulation (CFR) to reflect the 
disapproval of the SIP.
    The State proposed the DERC SIP revision for public review on 
August 6, 2008 and the comment period closed September 12, 2008; final 
adoption of the revision was on December 10, 2008, in order to meet the 
condition to submit a complete DERC SIP revision to EPA by March 1, 
2009, and implement the DERC SIP revision by March 1, 2009. As 
described in the proposed rule (73 FR 40203), if the State adopts and 
submits to EPA by March 1, 2009, a complete DERC SIP revision, and EPA 
determines through rulemaking that the submitted DERC SIP revision is 
approvable, we will simultaneously convert the conditional approval of 
the attainment demonstration SIP to a full approval. If EPA cannot 
fully approve the SIP revision concerning the use of DERCs in the DFW 
area, EPA will undertake rulemaking to disapprove the submitted DERC 
SIP revision and to convert the conditional approval of the attainment 
demonstration SIP for the DFW area to a disapproval. In such case, the 
18-month clock for sanctions and the 2-year clock for a FIP would start 
on the effective date of final disapproval.
    Today's final conditional approval of the attainment demonstration 
SIP remains in effect until EPA either determines that the State has 
not submitted a complete DERC SIP revision by March 1, 2009 or EPA 
completes rulemaking action either approving or disapproving a complete 
submitted DERC SIP submission and simultaneous with action on the DERC 
SIP submission takes final action to convert the conditional approval 
to a full approval or disapproval of the attainment demonstration.

IV. What Other Elements Must Be Approved To Allow This Final 
Conditional Approval of the Attainment Demonstration SIP?

    In our proposal, we discussed the elements that must be approved if 
we are to finalize the conditional approval of the attainment 
demonstration. In order to finalize conditional approval of the DFW 
1997 8-hour ozone attainment demonstration SIP, EPA must fully approve 
all of the control measures relied upon in the attainment demonstration 
and the DFW RFP Plan with the RFP MVEBs and RFP contingency measures. 
We approved the DFW RFP Plan with the RFP MVEBs and RFP contingency 
measures on October 7, 2008 at 73 FR 58475.
    The State committed to submit a rule restricting DERC usage by 
March 1, 2009. In addition, EPA reviewed all DERC Notice of Intent to 
Use Forms that the TCEQ Executive Director approved as of November 30 
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.
    Table 1 below lists the status of EPA action on the control 
measures relied upon in the attainment demonstration. The Table 
documents that, as of this final action, all control measures and 
reductions relied upon to demonstrate attainment have been reviewed and 
approved by EPA in this or other Federal Register Actions.

   Table 1--Status of EPA Required Action on Control Strategies Before
   Finalizing Conditional Approval of the Attainment Demonstration SIP
------------------------------------------------------------------------
                Measure                               Status
------------------------------------------------------------------------
The April 9, 2003 Alcoa Federal Consent  Approved August 15, 2008 (73 FR
 Decree.                                  47835).
The DFW Energy Efficiency Measures       Approved August 15, 2008 (73 FR
 Program.                                 47835).
NOX rules for IC engines in DFW........  Approved August 15, 2008 (73 FR
                                          47835).

[[Page 1906]]

2002 Base Year Emissions Inventory.....  Approved August 15, 2008 (73 FR
                                          47835).
The VOC rules adopted by Texas on 11/15/ Approved July 17, 2008 (73 FR
 06.                                      40972).
1-hour attainment determination........  Approved October 16, 2008 (73
                                          FR 61357).
East Texas Combustion Sources (i.e.,     Approved December 3, 2008 (73
 the rich burn gas-fired engine rule in   FR 73562).
 the 33 counties east of DFW).
The DFW major source rule..............  Approved December 3, 2008 (73
                                          FR 73562).
The DFW minor source rule..............  Approved December 3, 2008 (73
                                          FR 73562).
The DFW gas-fired engine rule..........  Approved December 3, 2008 (73
                                          FR 73562).
The DFW EGUs rule......................  Approved December 3, 2008 (73
                                          FR 73562).
The DFW non-EGUs rule..................  Approved December 3, 2008 (73
                                          FR 73562).
The Auxiliary steam boilers rule in the  Approved December 3, 2008 (73
 5 counties.                              FR 73562).
The Stationary gas turbines rule in the  Approved December 3, 2008 (73
 5 counties.                              FR 73562).
The Cement kiln rules..................  Approved simultaneously in
                                          today's Federal Register.
The VMEP and its emission reductions...  Approved in this rulemaking.
The TCMs and the associated emission     Approved in this rulemaking.
 reductions.
The TERP emission reductions...........  Approved in this rulemaking as
                                          submitted in the DFW 5% IOP
                                          Plan and the DFW 1997 8-hour
                                          ozone attainment demonstration
                                          SIP.
------------------------------------------------------------------------

V. Comments

A. What Comments Did EPA Receive on the July 14, 2008 Proposed 
Rulemaking for DFW?

    We received 26 comment letters on the proposed rulemaking. These 
comments are available for review in the docket for this rulemaking. 
The comment letters came from the following sources:

    1. August 6, 2008 letter from Linda Koop, City of Dallas 
Councilmember, District 11, Chair of the Transportation and 
Environment Committee.
    2. August 12, 2008 letter from Ramon Alvarez, PhD, for 
Environmental Defense Fund.
    3. August 12, 2008 letter from Bill Cox, citizen.
    4. August 12, 2008 letter from Margaret DeMoss, public health 
consultant and citizen.
    5. August 12, 2008 letter from Ed Soph, citizen.
    6. August 12, 2008 letter from Bob Fusinato, citizen.
    7. August 12, 2008 letter from Ramsey Sprague, citizen.
    8. August 13, 2008 letter from Jon Mamula, citizen.
    9. August 13, 2008 letter from Kerrie Kimberling, citizen.
    10. August 13, 2008 letter from Cindy Crutch, citizen.
    11. August 13, 2008 letter from Becky Bornhorst, clean air 
advocate.
    12. August 13, 2008 letter from Barbara Downey, citizen.
    13. August 13, 2008 letter from Ricky Pearce, Ryan Whaley 
Coldiron Shandy PC, for Holcim LP.
    14. August 13, 2008 letter from Neil Carman, for Sierra Club, 
Lone Star Chapter.
    15. August 13, 2008 letter from Gina Hall, citizen.
    16. August 13, 2008 letter from Molly Rooke, citizen.
    17. August 13, 2008 letter from Marc Chytilo, for Downwinders At 
Risk and the Lone Star Chapter of the Sierra Club.
    18. August 13, 2008 letter from April Johnson, citizen.
    19. August 13, 2008 letter from Wendi Hammond, for KIDS 4 Clean 
Air and Clean Air Institute of Texas.
    20. August 13, 2008 letter from Willem and Paula Noteboom, 
citizens.
    21. August 13, 2008 letter from Susan Waskey, citizen.
    22. August 13, 2008 letter from Matthew Kuryla, Baker and Botts 
for the BCCA Appeal Group.
    23. August 13, 2008 letter from Matthew Kuryla, Baker and Botts 
for the 8-Hour Ozone SIP Coalition.
    24. August 13, 2008 letter from Lon Burnham, State 
Representative, District 90, Fort Worth, Texas.
    25. August 14, 2008 letter from Anna Albers, citizen.
    26. August 14, 2008 letter from Sandra Soria, citizen.

B. General Comments

    Comment: Several commenters urge EPA to finalize conditional 
approval of the attainment demonstration SIP. One supports EPA's 
proposed rule, recognizes the efforts of the local community, and lists 
some of the clean air initiatives implemented by the City of Dallas.
    Response: We appreciate the support expressed in these comment 
letters. We applaud the actions taken by the local community and 
commend the local leaders and implementation staff; their work has and 
will continue to assist the area in reducing NOX and VOCs, 
the precursors for ambient ozone pollution. EPA encourages local 
governments to continue to be involved in these and future local 
emissions reductions programs.
    Comment: Two commenters disagree with EPA's position taken in the 
proposal that because the DFW area has an attainment deadline of June 
15, 2010, air quality monitoring data for the years 2007, 2008, and 
2009 would be used to make an attainment determination. Rather, using 
the years 2008, 2009, and 2010 would be most consistent with the Act's 
requirements for attainment determination. They note that the Act 
mandates the attainment determination be made within 6 months after the 
attainment date, including any extensions thereof, and be based on the 
area's design value as of the attainment date. Although the Phase 1 
Rule defines the ``attainment year ozone season'' as the ozone season 
immediately preceding the attainment date, they contend that that 
regulatory definition can be read as requiring controls timely for 
attainment in the attainment year, as required by the statute. They do 
not see the definition as relevant to the timing or content of an 
attainment determination. EPA's regulations do not specify that the 
attainment determination is to be conducted using data from the years 
prior to the attainment date, without considering data from the ozone 
season that includes the attainment date. They believe such a 
determination would be inconsistent with the statutory directive that 
the attainment determination be ``based on the area's design value (as 
of the attainment date).''
    Response: As an initial matter, EPA set forth its interpretation on 
this issue in the preambles to the proposed and final Phase 1 Rule. See 
68 FR 32802, at 32817 (June 2, 2003) (In ``determining whether an area 
actually attains the NAAQS at the time of the attainment date, EPA 
would use the ambient air quality data for the three ozone seasons 
prior to the attainment date. As an example, if the effective date of 
the

[[Page 1907]]

nonattainment designations is May 15, 2004, the maximum attainment date 
for an area classified marginal would be May 15, 2007. In this example, 
EPA would consider the 8-hour ozone data for the three previous ozone 
seasons--2004, 2005 and 2006.''); 69 FR 23951, at 23989 (Apr. 30, 2004) 
(noting that the ozone seasons from 2007, 2008 and 2009 would be 
considered for an attainment date in May 2010). However, as noted by 
the commenter, the statute clearly specifies that a determination of 
attainment must be ``based on the area's design value (as of the 
attainment date). The attainment date for the DFW area is June 15, 2010 
and the design value ``as of the attainment date'' must be determined 
using the last three full years of ozone data, i.e., 2007, 2008 and 
2009. We see no argument that the design value ``as of the attainment 
date'' could be determined based on air quality data that would not 
represent a complete ozone season and thus be incomplete as of June 15, 
2010.
    Comment: We received many comment letters stating that the plan 
does not reflect recommendations made by the North Texas Clean Air 
Steering Committee.
    Response: We agree that the plan submitted by the State does not 
reflect all of these recommendations. The resolutions were submitted to 
the State and addressed by the TCEQ in the SIP package adopted on May 
23, 2007, which is in the docket for this rulemaking. The U.S. Supreme 
Court has consistently held that under the Act, initial and primary 
responsibility for deciding what emissions reductions will be required 
from which sources is left to the discretion of the States. Whitman v. 
Am. Trucking Ass'ns, 531 U.S. 457 (2001); Train v. NRDC, 421 U.S. 60 
(1975). The State has discretion under the Act to determine the 
emissions reductions measures to be included in its attainment 
demonstration and exercised this authority for this plan. The State's 
role is to determine which particular emissions reductions measures are 
appropriate for the nonattainment area in order to comply with the 
requirements of the Act. As a matter of law, EPA is required to approve 
a SIP revision if it meets the Act's requirements, regardless of the 
State's choices. It is not EPA's role to rule out the State's choice of 
components of its SIP submittal so long as the plan is adequate to meet 
the standards mandated by EPA. See Train at 79-80 and Union Electric v. 
EPA, 427 U.S. 246 (1976). The EPA's role in reviewing SIP submittals is 
to approve state choices, if they meet the criteria of the Act. EPA 
disapproves a SIP submittal only if it fails to meet the statutory 
requirements. Seabrook v. Costle, 659 F.2d 1349 (5th Cir. 1981). 
Federal inquiry into the reasonableness of state action is not allowed 
under the Act (see, Union Electric Co. v. EPA, 427 U.S. 246, 255-266 
(1976); 42 U.S.C. 7410(a)(2)). As provided in the analyses accompanying 
this rulemaking, we have explained why we believe the submitted plan 
meets the requirements of the CAA.
    Comment: Many commenters claimed that the SIP sanctions ozone 
pollution levels above the 1997 standard yet this standard has been 
determined not to be protective of human health by the EPA and is being 
replaced.
    Response: The Act contemplates the possibility that scientific 
advances would require amending the ozone NAAQS. As such, Section 
109(d)(1) of the Act requires EPA to review the ozone standard every 
five years based on the current science, and make any revisions that 
are appropriate in light of the current science. Today's actions are 
being taken in the context of the ozone standard that was promulgated 
on July 18, 1997, based on the best available scientific evidence at 
the time.
    The 2008 revised 8-hour ozone standard does not replace the 
requirements for ozone nonattainment areas to meet the 1997 8-hour 
ozone standard by their applicable attainment date. The measures 
implemented in this attainment demonstration SIP will assist the DFW 
area in progressing toward the 2008 revised 8-hour ozone standard, 
ensuring progress continues during the time between the designations 
for the 2008 standard and the submission date for the associated SIP 
revisions. These measures cannot be removed from the SIP. South Coast 
Air Quality Management Dist. v. EPA, 472 F.3d 882 (DC Cir. 2006).
    Comment: A commenter stated that TCEQ approved a permit revision 
allowing TXI cement kilns in Ellis County to burn tires as fuel, 
questioned whether the change would result in a decrease in 
NOX emissions, and expressed concerns about other 
pollutants, which result from tire burning. TXI said there would be 
NOX reductions but they based this by comparing kilns that 
were not similar to the ones TXI would use. TCEQ allows TXI to self-
report, but the checks on the reporting are poor, and TXI also knows 
when the inspectors are coming.
    Response: Each cement plant in Ellis County must comply with both 
its permits' limits and the State's revised chapter 117 rules for 
cement kilns relied upon in the DFW attainment demonstration, whichever 
is stricter. In a related rulemaking in today's Federal Register, EPA 
is concurrently approving the revised chapter 117 rules for cement 
kilns. The revised cement kiln rules establish a NOX source 
cap for each of the three cement plants in Ellis County. We disagree 
that there will be no decreases in NOX emissions. The 
revised NOX rules for cement kilns should result in at least 
9.7 tpd of reduction in NOX emissions for the DFW area 
regardless of the fuel used including tires. We note also that all of 
the cement plants are required to operate continuous emissions monitors 
for NOX that must meet rigorous quality assurance and 
quality control criteria. Because these stack monitors must operate 
continuously, compliance does not rely solely on periodic inspections. 
As a consequence, EPA is confident that compliance with the 
NOX limits in these rules will be well monitored.
    The commenter's concerns regarding increases of other pollutants 
besides NOX, TXI's reliance upon non-similar kilns to claim 
NOX reductions, self-reporting, and TCEQ's inspection 
program are not pertinent to today's action; the issue in this action 
is whether the State has shown that the DFW area will attain the 1997 
standard by June 15, 2010.
    Comment: The public is disadvantaged by ``conditional approval'' 
comment periods. Comments concerning the adequacy of Texas' plan depend 
upon how Texas fulfills the requisite conditions, but the public will 
not know this information until sometime in the future after the 
current comment period has passed. After Texas adopts and submits its 
final plans concerning DERCs and the other ``conditions'' to EPA, EPA 
should allow additional public comment regarding the adequacy of the 
DFW SIP attainment demonstration.
    Response: Congress provided for conditional approval as a type of 
SIP processing. The Congress added section 110(k)(4) to the Act in the 
1990 amendments to codify the EPA's authority to conditionally approve 
SIPs. Section 110(k)(4) provides that EPA may conditionally approve a 
plan based on a commitment from the State to adopt specific enforceable 
measures by a date certain, but not later than one year after the date 
of the final conditional approval action. In this case, if the State 
submits by March 1, 2009 (the date certain), a complete DERC SIP 
revision submittal (the specific enforceable measures), EPA must 
reevaluate the approvability of the DFW attainment demonstration SIP, 
as revised by this DERC SIP revision submittal. EPA will perform such 
an evaluation through

[[Page 1908]]

notice-and-comment rulemaking and the public will have another 
opportunity to comment upon the adequacy of the DFW plan as affected by 
the DERC changes.
    Comment: A number of commenters are concerned that cities within 
the DFW nonattainment area continue to be given more time to attain the 
standard instead of requiring them to clean the air now. If the State 
had met its responsibilities to submit a timely and approvable 1-hour 
attainment demonstration SIP, then this SIP would be incrementally 
stronger and have been submitted and implemented sooner. There is a 
contention that Texas has not submitted a complete approvable 
attainment demonstration SIP for the DFW area for over thirty years. 
Moreover, monitoring began in the early 1970's and the DFW area has 
never attained the 84 parts per billion (ppb) standard and remains 
years from doing so.
    Response: The lack of approvability of past SIP submittals for the 
DFW area is not relevant to the requirement for an area to submit a 
1997 8-hour ozone attainment demonstration. The State submitted this 
SIP revision on May 30, 2007, fifteen days before the June 15, 2007 
required submission date. The State was on schedule to submit this SIP 
revision even earlier, but received requests from several stakeholders 
for an expanded timeline that would allow for a more robust stakeholder 
discussion and development of additional technical support.\1\
---------------------------------------------------------------------------

    \1\ See the Settlement Agreement and letters dated March 22, 
2006, March 24, 2006 and April 6, 2006 in the docket for this 
rulemaking.
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    This 8-hour ozone attainment demonstration was submitted on time 
and deemed complete by operation of law (40 CFR part 51, Appendix V). 
Moreover, the attainment date for the 1997 8-hour ozone standard for 
the DFW area is June 15, 2010. The State has not requested additional 
time for the area to attain this standard, nor has additional time been 
granted. EPA is finding today that the control measures relied upon in 
this plan, in combination with Federal Measures, and building on 
measures already approved in the SIP will ensure that the DFW area 
attains the 1997 8-hour ozone standard by the applicable attainment 
date of June 15, 2010.
    While past efforts to comply with CAA requirements have not been 
without flaws, we note that there have been extensive efforts and 
significant progress made over the years in the fast growing DFW area. 
These past efforts have built the foundation for the plan being 
approved today. They include the 15% Rate of Progress (ROP) plan, the 
post-1996 ROP plan, the MVEBs, and the extensive control measures 
adopted by the State and approved by EPA into the Texas SIP for the DFW 
area to meet the 1-hour ozone standard. The control measures in these 
approved plans included among other things: Reformulated gasoline, 
enhanced I/M, and controls on power plants locally and in the Central 
and East Texas Region.
    Moreover, we note that the area is continuing to look for further 
ways to address ozone levels and may submit additional revisions to the 
SIP in the future. Three of the largest cities (Arlington, Dallas and 
Fort Worth) have passed ordinances addressing the purchase of green 
cement, which may yield an additional 1 tpd of NOX 
reductions; and local city and county officials have increased their 
enforcement of Inspection and Maintenance rules by performing site 
inspections, which will yield additional reductions through 2009.
    The measures discussed above have resulted in significant 
improvements in air quality. The DFW area now is meeting the 1-hour 
standard and has made significant progress toward meeting the 1997 8-
hour ozone standard. As a moderate nonattainment area, the attainment 
date for the DFW area is June 15, 2010 and we believe the area will 
meet the attainment date.
    Comment: The plan should require more mass transit and industry to 
install the latest in air pollution reduction equipment. Airplane 
engines and related equipment should be less polluting.
    Response: As explained in an earlier response, the CAA places 
responsibility on the State to determine the mix of controls that will 
bring an area into attainment with a particular standard and EPA is 
delegated to reviewing whether the State's plan will meet the statutory 
attainment requirement. Therefore, EPA does not have the authority to 
require the State of Texas to submit a plan for the DFW area that 
requires more mass transit or imposes the latest in pollution control 
equipment on industry.
    We note, however, the expansion of mass transit is ongoing in the 
DFW area and can be viewed at http://www.DART.org. Appendix H of the 
DFW SIP submittal identifies emission reduction measures for airplanes 
and related equipment, which are part of the Voluntary Mobile Source 
Emission Reduction Program (VMEP) we are approving today. These 
include: Additional electrification of ground support equipment; gate 
electrification to eliminate use of aircraft auxiliary power units; 
ground tugs for pushback to minimize use of reverse thrust from main 
aircraft engines; de-peaking of airline flight schedules; and 
implementation of airport surface detection equipment to improve 
efficiency during taxi. Furthermore, the local community has 
implemented clean air initiatives that include: Outreach for the TERP 
and AirCheckTexas programs; reducing environmental impacts by 
purchasing hybrids and alternative fueled vehicles when possible; 
purchasing 40% of their electric power from renewable resources; green 
building policies; development of sustainability policies; developing 
purchasing policies for cleaner cement; and passing an ordinance 
prohibiting vehicles over 14,000 pounds from idling for more than 5 
minutes.
    In addition to the measures in Appendix H, TCEQ submitted a 
Supplement with more accurate and updated data for Love Field and the 
DFW International Airport, including data on activities and fleet mix. 
There were more new aircraft engines and the related equipment was less 
polluting than previously recognized. This information is provided in 
the docket for this rulemaking.

C. Comments on the Texas Emissions Reduction Plan (TERP)

    Comment: Commenters express significant concerns about whether the 
projected emissions reductions from TERP will occur, as predicted. They 
believe that the projections are overly optimistic. They provide the 
following reasons for their concern about the projections being too 
optimistic: 1. Actual TERP reductions have not met previous projected 
reductions, and the methodology for calculating the projected TERP 
reductions may not take into account that in the future, there will be 
fewer emissions reductions per dollar spent (cost-effectiveness 
assumption). 2. Although it is clear that TERP emissions reductions 
occur, there does not seem to be a satisfactory way to confirm the 
projected reductions will actually occur or not. 3. EPA relies upon the 
State's assumption that 70% of TERP funds will be used in the DFW area, 
but since there is no mechanism for ensuring the specified percentage 
of funding will be met, the projections are not enforceable; the 
projections should not be relied upon in the attainment demonstration; 
the 70% assumption should be reduced; and the SIP should include a 
contingency component to address a potential shortfall.

[[Page 1909]]

    Response: We agree that for the Increment of Progress SIP revision, 
the amount of actual TERP reductions was less than the projections. 
Because of this experience, we worked with the State to revise the 
methodology for estimating emission reductions in this attainment 
demonstration SIP. The revised methodology uses assumptions that are 
more conservative. Specifically, the average project life was increased 
by 40% and the cost effectiveness was reduced by slightly more than 
51%. The formula now relies upon the following assumptions: $6000/ton, 
250 days/yr operation and a 7-year project life. Using these revised 
assumptions, the TERP emission reduction projections relied upon in the 
demonstration modeling and the WOE are greatly reduced. Increasing the 
project life has the effect of reducing the emission reductions assumed 
in any given year. The cut in the revised cost-effectiveness assumption 
is intended to address, among other things, the commenters' concerns 
about there being fewer reductions per dollar spent each succeeding 
year.
    For comparison, on January 26, 2007, the cost effectiveness of TERP 
projects completed in DFW averaged $3730.24/ton; by September 23, 2007, 
DFW projects averaged $3743.59/ton; and by April 2, 2008, DFW projects 
averaged $3959/ton. California's experience with the Carl Moyer program 
\2\ has achieved emissions reductions at an average cost of $3900/ton 
through October 2006. We believe the revised cost effectiveness of 
$6000/ton provides room for the increase in cost/ton that we are seeing 
in the DFW area.
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    \2\ The Carl Moyer Program 2006 Status Report is in the docket 
for this rulemaking and can be viewed at http://www.arb.ca.gov/
msprog/moyer/status/2006status_report.pdf.
---------------------------------------------------------------------------

    In its May 2007 SIP revision, TCEQ indicated as a weight of 
evidence (WOE) measure that additional TERP reductions were possible if 
additional monies were appropriated by the legislature for the 2008/
2009 legislature. House Bill 1 signed by the Governor on July 15, 2007, 
appropriated to TCEQ, TERP funds of $297,144,243 for fiscal years (FYs) 
2008/2009. In the April 23, 2008 submittal, relying upon these 
additional appropriated monies, TCEQ projected that the TERP could 
potentially achieve an additional 14.2 tpd of NOX emissions 
reductions. Since these emissions reductions were not available early 
enough to include as control measures in the modeling, their impact on 
the DFW area's air quality was instead predicted by EPA, using 
sensitivity modeling runs, to estimate the ppb change on the monitors 
in the modeling-based weight of evidence (WOE) analysis.
    To achieve the projected additional 14.2 tpd of NOX 
emissions reductions from TERP, using the revised TERP methodology, the 
Texas legislature needed to appropriate to the TCEQ, sufficient FY2008 
and FY2009 \3\ TERP funds for the TCEQ to allocate a total of 
$149,100,000 \4\ to the DFW area for TERP Emission Reduction Incentive 
Grant (ERIG) projects; this amount does not include the funds required 
to achieve the IOP shortfall.\5\ TCEQ received a sufficient amount of 
TERP monies to have available $188,475,000 to achieve the IOP SIP 
shortfall ($39,375,000) and achieve an additional 14.2 tpd 
($149,100,000) in 2008 and 2009.
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    \3\ The TCEQ fiscal year runs from September 1 through August 
31.
    \4\ Using the revised SIP credit methodology, each ton costs 
(6000 x 250 x 7) = $10,500,000. Therefore, 14.2 x 10,500,000 = 
$149,100,000.
    \5\ Using the revised SIP credit methodology: 3.75 tpd x 
$10,500,000 = $39,375,000 to correct the IOP SIP shortfall.
---------------------------------------------------------------------------

    In the April 2008 submittal, the TCEQ posited that it could achieve 
the additional 14.2 tpd of TERP NOX reductions by spending 
in the DFW area 50% of the FY2008 TERP funds and 70% of the FY2009 TERP 
funds. Whether funds are spent in exactly these percentages each year 
however, is not the issue; the essential point is that TCEQ enters into 
TERP grant contracts worth at least $149,100,000 in the DFW area for 
projects to achieve 14.2 tpd in calendar years 2008 and early 2009.
    TCEQ roughly split in half for each fiscal year, the $297,144,243 
appropriated TERP funds--$148,572,121.50. Of this $148,572,121.50 
``split,'' TCEQ used approximately $40 million for other TERP programs, 
including rebate grants and FY2007 unfunded TERP applications, 
including the IOP SIP shortfall. EPA notes that the IOP shortfall has 
now been met. Considering the factors meant that TCEQ had approximately 
$106,000,000 FY2008 TERP monies for the FY2008 to achieve additional 
reductions beyond those considered in the May 2007 SIP submission 
through ERIG projects in TERP-eligible counties. Applications submitted 
to TCEQ during the FY2008 round of project applications totaled 
approximately $94.5 million for the DFW area. Of these applications 
however, it appears from the draft September Report that $51,532,511.79 
have been selected for funding.\6\
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    \6\ Per the TERP Biennial Report to the Texas Legislature 
December 2008 draft, dated September 22, 2008. This draft was 
prepared using data from mid-summer. The final report, due in 
December 2008, will incorporate all of the contracts awarded or 
pending to date. See the docket for this rulemaking.
---------------------------------------------------------------------------

    As a result, to achieve the 14.2 tpd projection, TCEQ needs to 
enter into FY2009 TERP grant contracts worth $97,567,488.21 
($149,100,000 - 51,532,511.79 = $97,567,488.21). In summary, after 
accounting for the tpd of TERP NOX emissions reductions 
obtained by the FY2008 grant contracts, to obtain the remaining tpd of 
TERP NOX emissions reductions to achieve a total of 14.2 tpd 
as projected as part of the WOE, the TCEQ would need to enter into TERP 
grant contracts with DFW-area applicants worth $149,100,000 for 
projects to be completed as early as possible in calendar 2009. Due to 
a number of factors, including Hurricane Ike, the TCEQ will begin its 
first round of requests for funding from FY2009 TERP grant monies in 
December 2008. For more information concerning the timing of FY2009 
TERP projects due to Hurricane Ike, please see the Supplemental TSD 
dated December 2008.
    TERP has safeguards to ensure that when funds are provided to 
grantees, they must achieve the associated reductions. Grantees are 
required to track usage and report to the TCEQ every six months; they 
must meet the reporting requirements delineated in their specific grant 
contract. TERP is enforceable against the grant recipient. Over the 
activity life of each TERP grant-funded activity, the grant recipient 
commits the generated emissions reductions to the SIP. The recipient is 
responsible for achieving the annual and total NOX emissions 
reductions within the eligible areas as defined in the contract. 
Recipients will be required to return all or a pro rata share of the 
grant funds to the TCEQ if the emissions reductions are not achieved.
    EPA continues to carefully review the biennial reports that TCEQ is 
required to submit to the Legislature pursuant to Texas Health and 
Safety Code, 386.057 and 386.116(d). The draft September TERP Biennial 
Report to the Texas Legislature indicates that 488 projects have been 
selected for funding in the DFW area, totaling $51,532,511.79 to reduce 
an estimated 3.72 tpd in NOX emissions beyond what was 
included in the May 2007 modeling. Based upon the draft September 
Report, the average cost/ton for these projects increased to $6710.13, 
versus the revised methodology of $6000/ton. At this rate, to achieve 
the 14.2 tpd in NOX emissions reductions, the TCEQ must be

[[Page 1910]]

able to allocate at least $123 million \7\ to the DFW area for TERP 
projects early in calendar 2009. As this report is in draft, these 
numbers are subject to change but it now seems likely that 
approximately 70% of these TERP emission reductions will occur before 
the core ozone season of 2009. We have evaluated the impact of this 
change on the attainment demonstration modeling and WOE; this 
evaluation is in Subsection D, below.
---------------------------------------------------------------------------

    \7\ (6710.13 x 250 x 7) = $11,742,727.50 x 10.4786 = 
$123,047,344.38.
---------------------------------------------------------------------------

    In summary, EPA believes that the TERP program is achieving 
significant reductions in NOX. Consistent with its 
experience in implementing the program, the State has adjusted its 
assumptions used in projecting emission reductions to be more 
conservative. EPA believes these revised assumptions begin to address 
many of the commenters concerns. Although delays in opening the request 
for applications mean the reductions based on FY2009 funds will be 
delayed, many reductions can still occur before the peak of the ozone 
season. Achieving the 14.2 tpd of reductions from TERP will require 
substantial continued efforts. See also Subsection D below, in 
particular the last Response, Comment MC-15.

D. Comments on Photochemical Modeling, Weight of Evidence Analyses, and 
Assessment of Demonstration of Attainment

    EPA received a number of comments about the photochemical modeling, 
the Weight of Evidence Analyses, and our proposed determination that 
the area would attain the standard by its attainment date of June 15, 
2010. EPA has reviewed all the comments on these topics and provided 
responses below.
    The discussion below summarizes our evaluation of the modeling and 
evidence, the comments we received, and other factors such as the 
State's progress in implementing control strategies, and recent air 
quality trends. EPA believes that as the attainment date becomes 
closer, measured air quality and planned additional emission reductions 
become more important as a predictive tool (compared to modeling) and 
the monitoring data should be given additional weight, more so than in 
situations where the attainment date is still years away. In 2008, the 
preliminary data shows 18 of the 20 monitors have measured attainment 
levels with fourth high 8-hour values of 84 ppb or less. The remaining 
two monitors were only slightly higher than an attainment level 
measuring fourth high values of 85 ppb. EPA believes additional 
significant reductions in emissions will occur before the 2009 ozone 
season such that the area can attain the standard based on 2007-2009 
ambient data or at least qualify for a 1-year extension of the 
attainment date by having each monitor's 4th high ozone concentration 
in 2009 below 85 ppb.
    We evaluated many factors in our WOE evaluation. These items 
included reductions not included in the modeling based projections 
(energy efficiencies), unquantifiable measures (AirCheckTexas, Dallas 
Sustainable Skyline Initiative, etc.), meteorological analyses of 
severity of ozone seasons (both the base period and recent years 
including 2007), most recent monitoring in 2007 (a 4th high of 89 ppb 
at two monitors and the other 18 monitors had 4th high values of 87 ppb 
or less), the court's vacatur of CAIR, progress in implementing the 
TERP program, and progress in implementing the early compliance 
incentive on natural gas compressor engines outside the DFW area. EPA 
has also considered preliminary 2008 ozone monitoring data (4th high 
values of 85 ppb at two monitors and at the other 18 monitors the value 
was 84 ppb or less) and whether that data supports a trend toward 
attainment for the area. We considered that over half of the 
NOX estimated emissions reductions between 2007 and 2009 
that are estimated to yield a 3-4 ppb drop in ozone levels in the DFW 
area, are slated to occur between the 2008 ozone season and the 2009 
ozone season. We also expect further ozone reductions in 2009 and 
beyond.
    After consideration of all of these analyses, EPA has determined 
that the State has demonstrated that the DFW nonattainment area will 
attain the 1997 8-hour ozone standard by its attainment date.
    Comment (MC-1): A commenter states that the WOE analysis 
underestimates the impact of emission increases from facilities outside 
the DFW nonattainment area, upon the DFW area. This underestimate 
occurs because the TCEQ issues PSD permits to facilities outside the 
DFW area that will affect the ozone concentration level in the DFW area 
and says they should address these ozone impacts in the DFW attainment 
demonstration SIP. The commenter does not believe that this DFW 
attainment demonstration accounts for the impacts from these sources 
that have been and will be permitted outside of the DFW area. There 
also appears to be no correlation or tracking of these permitted 
emission increases in relation to the projected point source emissions 
inventories in this DFW attainment demonstration.
    Response (MC-1): The Texas SIP at Section 166.160 (a) (which 
incorporates 40 CFR 52.21(k) by reference) requires a new source or 
modification subject to PSD to demonstrate that emissions from the 
facility will not cause or contribute to a violation of any NAAQS. The 
Texas PSD SIP permitting program also provides for an opportunity for 
notice and comment, as well as state court judicial review, of each 
permitting action.
    EPA disagrees with the commenter that this SIP revision does not 
account for the impact of potential emissions increases. In this final 
action on the DFW attainment demonstration, we reviewed the analysis to 
insure that sources impacting the DFW nonattainment area were included 
in the baseline and future case modeling demonstrations. EPA's modeling 
guidance (``Guidance on the Use of Models and Other Analyses for 
Demonstrating Attainment of Air Quality Goals for Ozone, PM2.5, and 
Regional Haze'', EPA-454/B-07-002, April 2007; and earlier modeling 
guidance) and emission inventory guidance (``Emissions Inventory 
Guidance for Implementation of Ozone and Particulate Matter National 
Ambient Air Quality Standards (NAAQS) and Regional Haze Regulations'', 
EPA-454/R-05-001, August, 2005, updated November 2005) indicate that a 
combination of specific projections and general growth estimates should 
be utilized to attempt to obtain a best estimate for the future year 
inventory. Future case emissions must be projected to account for 
growth and control throughout the modeling domain, which includes 
states outside of Texas and the attainment areas of Texas (including 
the new proposed sources raised by the commenter). EPA's guidance has 
been that new permitted sources, including likely to be permitted 
sources based on applications that have been received when the future 
year EI is being generated, should be included in the future year 
modeling if they are expected to be emitting in the future attainment 
year. As a practical matter, the focus has usually been to include 
expected new very large sources (such as electric generating units 
(EGUs)) and use economic based growth factors to account for growth in 
emissions from other industrial source categories. Overall, EPA's 
guidance is to provide the best estimate of the future year emission 
inventory given the limitations with estimating emissions several years 
in the future. Texas' emission projections to the future years are very

[[Page 1911]]

detailed and the methods utilized are discussed in the MOAAD TSD and in 
TCEQ's DFW SIP submittal, including Appendix B. In nonattainment areas, 
major new sources are required to obtain offsets larger than the 
proposed source so there is a net decrease in emissions, so no growth 
is estimated for these sources in nonattainment areas. Therefore, 
within Texas the only areas that point source growth is estimated is in 
the areas that are in attainment and our discussion will briefly 
explain the methodology for future year estimates of major point 
sources in attainment areas of Texas.
    For existing EGUs in Texas, the State used 2005 continuous emission 
monitoring data and assumed that there would be no emissions changes. 
Texas projected increases in emissions because of new EGUs that were 
expected to be emitting in 2009 (these were included in Table 2-8 of 
Appendix B of TCEQ's submittal). For all other industrial point source 
emissions (non-EGUs) in Texas' attainment areas, TCEQ started with the 
1999 reported emission inventory and projected growth in point source 
emissions using point source growth projections derived from the 
Emissions Growth Analysis System version 4.0 (EGAS 4.0), an EPA-
approved methodology. It is worth noting that the EGAS system for 
projecting emissions tends to overstate future emissions since the 
system relies principally on economic growth for the projections, and 
does not include reductions from regulatory or permit controls.
    In conclusion, we have reviewed the methodologies that TCEQ 
utilized to grow EGUs and non-EGUs outside of the DFW area and conclude 
that the 2009 level emissions of these sources have been appropriately 
estimated using acceptable methods and contrary to the commenter's 
concerns the attainment demonstration appropriately accounts for the 
potential for new source growth by 2009.
    Comment (MC-2): Commenters state that ozone exceedances continue to 
occur in the DFW area and show there still is a serious problem. 
Specifically, 14 exceedances have been measured at eight of the 
monitors through August 12, 2008 and eight of which are 90 to 99 ppb. 
The commenter concluded that this 2008 monitoring data does not seem to 
support the WOE.
    Response (MC-2): EPA has reviewed the ozone monitoring data through 
November 1, 2008 in response to this comment. While a number of 
exceedances of the 1997 8-hour ozone standard occurred during the 2008 
ozone season by August 12, 2008, it is very important to note that the 
standard is a statistically based standard. The statistical nature of 
the standard allows each monitor to have up to 3 days with exceedance 
levels at each monitor (with potentially multiple 8-hour exceedances 
for each of the three days) and all the monitors in the area could 
still have a 4th high value less than 85 ppb (attainment level). The 
standard is an average of the daily 4th high value at a monitor for 
each year of a consecutive 3-year period. Therefore, it is even 
possible to have a 4th high value for one or even two years at a 
specific monitor be above the standard, but the 3-year average value to 
be below 85 ppb and thus, in attainment.\8\ Furthermore, each monitor 
in the area could have up to 3 exceedances at each monitor on differing 
days. Given 20 monitors in the DFW area, a total of 60 exceedances 
could theoretically occur in the DFW area with all 4th high values at 
each monitor still less than 85 ppb. This is a theoretical worse-case 
situation but this demonstrates that having several exceedances does 
not automatically yield a nonattainment determination.
---------------------------------------------------------------------------

    \8\ For example, if the 4th high value for each of three years 
was as follows: 2006--87 ppb; 2007--85 ppb; 2008--81 ppb, the 
average over the three year period would be 84 ppb, which is below 
the level of the standard.
---------------------------------------------------------------------------

    Since the standard is statistically based, the relevant metric to 
examine for determining compliance with the NAAQS is the annual 4th 
high values at each monitor. We therefore evaluated the recent 4th high 
values for the DFW area 8-Hour Ozone Season (March 1-October 31 for the 
85 ppb standard). The 4th high monitoring data from 2008 indicates that 
the area is near attainment levels (2008 monitoring data is preliminary 
and awaiting QA/QC \9\). The 2008 preliminary data shows the DFW area 
had 4th high values of 85 ppb at two monitors and at the other 18 
monitors the value was 84 ppb or less. The 2008 preliminary data 
indicates the 2006-2008 DV is 91 ppb (down from 95 ppb using 2005-2007 
data). For the monitor that has the highest average 2007 and 2008 4th 
high values and is likely to be the controlling monitor (or one of the 
highest monitors) for determining if the area reaches attainment based 
on 2007-2009 data, the monitor's DV for the 2007-2009 period would have 
to be less than 85 ppb. For this to occur the monitor (Denton monitor) 
would have to have a 4th high value of 82 ppb or less to reach 
attainment in 2009. It is important to note that this monitor had a 
preliminary 4th high value in 2008 of only 84 ppb.
---------------------------------------------------------------------------

    \9\ 2008 preliminary monitoring data is from EPA's AQS and 
AirNow databases and has to undergo final Quality Assurance and 
Quality Control.
---------------------------------------------------------------------------

    In comparison with ozone monitoring levels in 2007, the preliminary 
2008 monitoring data is lower than the 2007 data. Contrary to the 
commenters concerns, EPA believes that the 2008 preliminary data is 
consistent with achieving attainment, especially considering that much 
of the DFW SIP reductions are still to occur and another year of fleet 
turnover will happen. EPA also believes that even if the area does not 
attain the standard based on 2007-2009 data, it is very likely to 
qualify for a one year extension under sections 172(a)(2)(C) and 
181(a)(5) of the Act (see 40 CFR 51.907) by having fourth high at 84 
ppb or below at every monitor.
    Comment (MC-3): Commenters believe that we should impose a 2009 
mid-course review (MCR) obligation upon the State, triggered by 
exceedances at the monitors or a violation of the standard in 2009.
    Response (MC-3): There is no MCR requirement at this time for the 
8-hour ozone SIP. In our Phase 2 Implementation Rule, we provided that 
we would assess the need for MCR for areas with an attainment date 
beyond 6 years after the effective date of the area's designation 
(Final Rule To Implement the 8-Hour Ozone National Ambient Air Quality 
Standard, Phase 2 (70 FR 71612, 71629). The attainment date for DFW is 
June 15, 2010, which is not more than 6 years beyond the effective date 
of the area's designation. A mid-course review is for the purpose of 
assessing whether an area is on-track for attainment and would 
typically be performed several years before the attainment year. This 
is because a MCR performed several years before the attainment year 
would give the area sufficient time to make corrections to the plan if 
it was not performing as anticipated. A review as suggested by the 
commenter would not be ``mid-course'' because it would be performed in 
the middle of the attainment year ozone season. At that point in time, 
there would be no steps that the DFW area could take to move the area 
back on track to achieve attainment by the required date.
    Comment (MC-4): Commenters stated that in the DFW area, there are 
two monitors critical to the attainment demonstration, one in Frisco 
and one in Denton. The commenters, relying upon a February 22, 2006 
Memorandum from ENVIRON, state that there is no measurable impact on 
these two critical monitors from the TCEQ's chosen controls for the 
Ellis County cement plants. The commenters contend that TCEQ has not 
performed any analysis showing that the chosen level of

[[Page 1912]]

controls on the Ellis County cement plants would assist the DFW area 
into coming into compliance with the ozone standard.
    Response (MC-4): As noted in a previous response, the Act gives the 
State the primary authority to determine the mix of control measures 
necessary to demonstrate attainment. One of the measures that TCEQ 
selected in support of its attainment demonstration is controls at 
cement plants in Ellis County. EPA evaluated the plan, as a whole, and 
agrees that the State has demonstrated that the area will attain the 
standard by its attainment date. Thus, EPA does not have authority to 
second-guess the mix of controls selected by the State and, in this 
case, its decision to further control the cement kilns in Ellis County.
    Although we cannot second-guess the controls selected by the State, 
we note that we agree with TCEQ that cement kiln NOX 
reductions are an important element of the reductions necessary to 
bring the entire DFW area into attainment and the reductions are 
expected to reduce high ozone levels and the frequency of ozone 
exceedances in the DFW area. The record for this action includes the 
information that was evaluated by the State and EPA and that supports 
the conclusion that additional NOX controls on cement kilns 
are a critical component to reducing ozone exceedance levels in the DFW 
area so that the area can timely attain the 1997 8-hour ozone standard. 
It is clear from evaluating the SIP, its reports and appendices that 
TCEQ has performed numerous analyses concerning the impact of the 
cement kilns NOX and VOC emissions on the ozone 
concentrations levels of the DFW area. Moreover, contrary to the 
commenters' assertion, the chosen strategy has an impact on the Frisco 
and Denton monitors, as well as a significant benefit to the western 
portion of the nonattainment area, especially in Tarrant County. For 
further details, see the TCEQ's Response to Comments document, the 
MOAAD TSD, and the Supplemental TSD.
    For the other comments specific to the cement kiln NOX 
rule itself, not the attainment demonstration SIP, we provide the 
comments and our responses in our final rule for the Control of 
Emissions of Nitrogen Oxides from Cement Kilns, concurrently published 
in today's Federal Register.
    Comment (MC-5): The commenter asserted that EPA should not accept 
TCEQ's revised Relative Response Factor (RRF) calculation.\10\ The 
commenter indicated that contrary to the proposal, a 1 ppb difference 
between EPA's RRF guidance and TCEQ's revised RRF is significant. The 
commenter referred to 73 FR 40211, stating that TCEQ RRF calculation 
did not make significant differences in the future design values (FDVs) 
with truncation. The commenter wrote that TCEQ's methodology is merely 
a paper exercise to obtain additional emission credits, and EPA should 
not approve of such tactics.
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    \10\ The RRF is used to calculate the change in model projected 
values between the basecase and future case modeling projections and 
determine if modeling is projecting attainment in the future. For 
further explanations of both the EPA guidance method for calculating 
RRFs and TCEQ's RRF calculation method see Section 4.11 of the MOAAD 
TSD.
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    Response (MC-5): We recognize the TCEQ's method of projecting the 
future design value differs from the method provided for in EPA's 
guidance. EPA's guidance for projecting the future design value is not 
a legally binding substantive rule. Therefore, other methods of design 
value projections may be evaluated on a case-by-case basis and used to 
determine whether an area will meet the standard. Whatever method is 
used for a specific demonstration--either that from EPA's Guidance or 
another method--is subject to comment during the State and EPA public 
participation processes and all substantive concerns about the method 
would be addressed in responding to any comments.
    TCEQ shared their RRF method with EPA during their SIP development 
process. EPA reviewed the alternate RRF method at the time and 
indicated to TCEQ that we would utilize both EPA's method and TCEQ's 
method and weigh the results in our review of the modeling projections. 
We have continued to follow this approach in our review of this SIP. 
For details on how both the TCEQ and EPA RRF methods are calculated and 
results from the two methods, please see the MOAAD TSD starting in 
Chapter 4.
    In this specific case, TCEQ's method yields projected values that 
when compared to values with EPA's method are more conservative at some 
monitors and less conservative at other monitors. EPA does not consider 
the TCEQ RRF method to be superior to EPA's method, just a different 
way to perform the calculation and yield another set of projected 
results to consider in our review. We do not believe that either method 
is biased towards a particular result. As described below, and 
documented in our MOAAD TSD for this action, we have reviewed 
projections using both RRF techniques. Both the TCEQ projection and the 
EPA projection are consistent with the conclusion that the area will 
meet the standard in 2009.
    The results for both RRF (EPA and TCEQ) methods are contained in 
tables of the MOAAD TSD that have FDV projections, including Tables in 
Chapter 6 (the Summary Chapter). EPA reviewed the FDVs for all modeling 
based projections using both RRF techniques and for most monitors, the 
TCEQ RRF based FDV calculations make minor differences of only one or 
two tenths of a ppb (compared to EPA's RRF method) and generally do not 
change the final modeling projected value. Specifically, for the nine 
monitors that are assessed, the difference between the two RRF 
techniques ranges from minus 0.22 ppb to +0.19 ppb for 8 of the 9 
monitors and is +0.59 ppb for the other monitor. See Table 5 of the 
proposal notice. As the final step of calculating modeling projections, 
EPA guidance recommends truncating the tenths digit and only reporting 
integer ppb values to match with the monitored attainment demonstration 
procedures that truncate to integer ppb levels. Due to this truncation 
procedure, modeling projection changes of a few tenths do not generally 
impact the final FDV value. There were a few cases where the different 
RRF methods yielded a 1 ppb difference in the final FDV value due to 
this truncation process (for the Midlothian monitor's data, the 
different RRF methods yield modeling values of 82.83 ppb and 83.05 ppb 
and truncation yields final FDVs of 82 ppb and 83 ppb).
    We continue to believe that the difference in the results of these 
two techniques is small overall. As discussed in another response 
below, we considered the results of both RRF methods (including the few 
times that the truncated FDV differed by 1 ppb) and determined that 
both the TCEQ projection and the EPA projection are consistent with the 
conclusion that the area will meet the standard in 2009.
    Comment (MC-6): The commenter indicated it is unclear whether the 
Photochemical Dispersion Modeling Reanalysis 2009 (PDMR 2009) 
evaluation uses TCEQ's revised RRF or EPA's guidance. The commenter 
indicated that it appears as though it uses only TCEQ's RRF and the 
public should be afforded an opportunity to know the PDMR 2009 FDV 
under EPA's guidance. The commenter asserted that considering that even 
with the more lenient TCEQ revised RRF, the modeling still projects a 
worse air quality picture, and thus the EPA guidance projection

[[Page 1913]]

will most likely be even worse. The commenter indicated that without 
this information, the public is unable to meaningfully review and 
comment not only on the overall demonstration, but also on whether 
using the TCEQ revised RRF is even proper.
    Response (MC-6): There were five tables that included modeling 
projections in the proposal notice. Tables 2, 3, and 5 had projections 
for the PDMR 2009 modeling scenario and were marked as TCEQ RRF in the 
FDV columns. The proposal notice included calculations of modeling 
projections using both the TCEQ's RRF method and the RRF method from 
EPA's guidance for the modeling run Combo 10 in Table 1. In referring 
to values in Table 1 of the proposal notice, EPA stated on page 40211 
``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.'' From that point forward in the proposal 
notice, EPA did not include the results from EPA's RRF method in the 
Federal Register notice. Tables 2, 3, and 5, including the analyses of 
PDMR 2009 only include the TCEQ RRFs as the commenter indicates. This 
was done to try to minimize confusion in the notice. EPA did note in 
the proposed notice that the results from the EPA RRF method are 
contained in the MOAAD TSD. The results for both RRF (EPA and TCEQ) 
methods were contained in tables of the MOAAD TSD that had Future 
Design Value projections, including Tables in Chapter 6 (the Summary 
Chapter). EPA reviewed the FDVs for all modeling based projections 
using both RRF techniques. Examination of the modeling results, which 
include some WOE adjustments contained in Table 6-3 of the MOAAD TSD, 
reveals that the TCEQ RRF based FDV calculation makes only minor 
differences of only one or two tenths of a ppb (compared to EPA's RRF 
method) for most monitors and did not change the final modeling 
projected value except for one monitor.
    Comment (MC-7): A commenter asserted that full credit for the 
NOX reductions from gas compressors in 33 East Texas 
counties seems overly optimistic. The commenter indicated that their 
understanding is that owners or operators of compressor engines 
requested a small portion of the $4 million in incentives. The 
commenter remains skeptical that the full reductions assumed in Combo 
10 will be achieved by 2009. The commenter asserted that the attainment 
modeling thus overstates the ozone reductions from the control strategy 
and indicated that EPA should consider this effect as part of the 
Weight of Evidence analysis, and should give more weight to the PDMR 
2009.
    Several commenters indicated that the 2.4 tpd of NOX 
reductions from point sources in the DFW area that have 2010 compliance 
dates are not likely to be in place by the beginning of the 2009 ozone 
season. These commenters also indicated that EPA assumes too much by 
relying on the predictions that early compliance will occur for certain 
control measures with 2010 implementation dates. They claim that 
because of this reliance, the attainment modeling overstates the ozone 
reductions from the control strategy. The commenters indicated that EPA 
should consider this effect as part of the WOE analysis, and should 
give more weight to the PDMR 2009. Furthermore, a commenter wrote that 
if any control measure emission reduction will not be enforceable until 
after the 2009 compliance date, then those emission reductions cannot 
be used to justify EPA's approval.
    Response (MC-7): Combo 10 modeling run was the official attainment 
demonstration modeling run submitted by TCEQ to EPA in the SIP revision 
submittal. Because of our concerns stemming from the inclusion of 
reductions from measures with 2010 compliance dates, it was not the 
only modeling run considered by EPA in our evaluation of whether the 
DFW area would attain the standard by the deadline. There was another 
modeling run available in the TCEQ's public record on its proposed 
action for EPA to review; in the proposal and TSDs, we label this 
additional modeling scenario the PDMR 2009. We evaluated this PDMR 2009 
modeling run as a worst-case projection of the 2009 modeling picture 
because it did not project any reductions from the rules with 2010 
compliance dates. For example, it did not include the 2.4 tpd of 
NOX reductions projected from the major and minor Point 
Source rules in the DFW area and any projected reductions from the East 
Texas Compressor Engines rules that have 2010 compliance dates. Thus, 
PDMR 2009 provides an upper boundary of projected ozone FDVs in the 
attainment year.
    The Texas legislature made available to compressor engine owner and 
operators $4 million to assist in early compliance. As the commenter 
points out, however, the full $4 million was not requested by owners 
and operators of compressor engines. Since some requests were made, 
some early compliance should occur, but the commenter is correct that 
the level of reductions in East Texas by the 2009 ozone season is 
probably closer to the PDMR 2009 emission reduction level than the 
Combo 10 emission reduction level. As a result of this information, EPA 
is putting more weight on the PDMR 2009 results than on Combo 10.
    We have evaluated the modeling outputs based on an approach that 
looks at the PDMR 2009 outputs, which predict ozone levels that are 
slightly worse than what is likely to occur, as well as the Combo 10 
outputs, which predict ozone levels that are more optimistic. This 
evaluation of PDMR 2009 sets the upper bound of model predictions for 
the FDV in 2009 and the Combo 10 run sets the lower bound. In making 
our determination that the State had demonstrated that the DFW area 
would attain the 1997 ozone NAAQS by its attainment date, we consider 
the TCEQ's official attainment demonstration modeling run (Combo 10), 
the results from the PDMR 2009 modeling, and information that some 
early compliance would occur by the 2009 ozone season as well as other 
weight of evidence analyses. The model projections in Table 6.3 of the 
MOAAD TSD give the non-truncated values for the final modeling with 
some WOE adjustments for both the modeling runs and both RRF 
techniques. The difference between the PDMR 2009 and the Combo 10 run 
for each monitor is 0.30 ppb or less when using either the TCEQ or EPA 
RRF technique. EPA's modeling guidance recommends the truncation of the 
decimal places and reporting of only integer values for the final 
modeling based projection values. When the truncation is done to the 
MOAAD TSD Table 6.3 values (Modeling-based assessment with some WOE 
elements included), the results are identical for both the PDMR 2009 
and the Combo 10 modeling runs. Using the EPA RRF procedure, both runs 
result with 7 monitors attaining, one monitor at 87 ppb, and one 
monitor at 88 ppb. Using the TCEQ RRF procedure, both runs result with 
7 monitors attaining, one monitor at 87 ppb, and one monitor at 88 ppb.
    We have considered both the PDMR 2009 and Combo 10 modeling results 
and put less weight on the Combo 10 projections because of concerns 
over the inclusion of measures with 2010 compliance dates. As discussed 
above, however, when EPA's procedures for projecting the future design 
value are followed, there is little difference in the results 
particularly if one considers that

[[Page 1914]]

a small amount of early compliance will occur. Therefore, as further 
discussed in response to other comments, the combination of the 
Modeling projections and other WOE elements were considered and support 
the conclusion that the area will attain by the area's attainment date.
    Comment (MC-8): The commenter indicated that TCEQ intends to reduce 
the amount of DERC values included in the modeling because using the 
entire balance of the DERC bank is ``overly conservative based on past 
usage of DERCs.'' The commenter asserted that DFW's past air quality 
violations occurred under scenarios of less DERC usage. The commenter 
concluded that this belies a Weight of Evidence (WOE) ``trend'' of 
improving air quality because in the future projection nothing is 
really changing from the past when violations occurred.
    Response (MC-8): DERCs are banked emission credits generated by 
reducing emissions beyond required levels that sources can use to 
exceed certain emission limits on a temporary basis. EPA guidance 
discusses why emission credits that are being carried in an emissions 
bank ought to be included in modeled projections. It can be important 
because these banked emissions come back in to the air if the banked 
credits are used. As a result, if these banked emissions are not 
accounted for in the future projections, the modeling would under-
predict future ozone levels if some or all of the banked credits are 
used. EPA guidance advises a conservative approach in which all banked 
emissions are included in the modeled future projections. This 
conservative approach assumes that the entire bank would be depleted 
during the attainment year. The TCEQ Bank held 20.4 tpd of 
NOX DERCs when TCEQ reviewed the level of credits in the 
bank and included the banked DERCs in their future year modeling. After 
finalizing the future year modeling, TCEQ reevaluated the inclusion of 
all of the banked DERCs in the future projections. TCEQ believed that 
the inclusion of the entire balance of the DERC bank was overly 
conservative based on past usage of DERCs. They wished to include 3.2 
tpd, rather than 20.4 tpd, of banked DERCs in the future projections. 
As discussed previously, Texas committed to adopt a restriction on DERC 
usage to ensure that no more than 3.2 tpd of banked DERCs will be used 
in 2009 and as a result preventing 17.2 tpd of potential emissions 
growth. This approval is conditioned on TCEQ's adoption and submittal 
of a complete SIP revision. Consequently, in order for EPA to fully 
approve the SIP, the State will need to have an enforceable rule in 
place that would not allow 17.2 tpd of the 20.4 tpd banked DERCs 
currently modeled in the state's 2009 Combo 10 and PDMR 2009 modeling, 
to be used beginning March 1, 2009.
    The modeling submitted May 30, 2007 did include 20.4 tpd of banked 
DERCs in the 2009 future projections. Relying upon the State's 
commitment to revise the DERC rule to limit the use of banked credits 
to 3.2 tpd in 2009, it is appropriate to reduce the 2009 future 
modeling projections to 3.2 tpd in 2009. (For the calendar years after 
2009, there will be an enforceable mechanism to equate to the limit of 
3.2 tpd.) EPA therefore adjusted the modeling projections in Table 3 of 
the proposal (also included in the MOAAD TSD) to assess the impacts of 
the revised future projections. This was done to provide a modeling 
projection that reflected the inclusion of banked DERCs of 3.2 tpd in 
2009. This approach is consistent with what would have been projected 
if TCEQ had redone the SIP modeling with 3.2 tpd for the banked DERCs 
instead of the 20.4 tpd that was included in the Combo 10 and PDMR 2009 
modeling. EPA then used the revised 2009 modeling projections in 
conjunction with other modeling based analysis and WOE considerations 
in our review of the entire attainment demonstration.
    The commenter is correct in the assessment that DERCs have not been 
used in the past and past air quality exceedances did not include any 
impact from DERC usage (since DERCs have not been used in the DFW 
area). Now, with the commitment to adopt a restriction on DERC use, it 
is not appropriate to continue with the assumption that all of the 
DERCs in the bank will be used in the attainment year in the future 
year modeling.
    Because DERC use did not impact past exceedances (again because 
DERCs have not been used in the past), EPA did not consider the banked 
DERCs 2009 usage restriction, as part of our emissions and ambient 
trends analysis that we performed in our WOE evaluation; rather, it is 
only in the modeling where it was considered. Consistent with the 
commenters concerns, EPA was careful in our WOE evaluations and review 
to not consider the revised 2009-banked DERCs usage restriction in our 
emission trends analysis and monitoring trends analysis. For example in 
Table 5-11 of the MOAAD TSD, estimating the actual emission reductions 
between 2007 and 2009, EPA did not include any reductions due to the 
restriction on DERC usage. Therefore, EPA believes that we have 
appropriately considered the revised banked DERCs tpd usage restriction 
in adjusting assumptions about possible future emissions growth in the 
modeling but consistent with the commenter's concerns, we have not 
considered it in evaluating emissions and monitoring trends (analysis 
included in the WOE analysis). For a full discussion of DERCs and 
conditional approval, see the DERCs comments section below.
    Comment (MC-9): The commenter indicated that EPA's reliance upon 
the low 2007 monitor readings is misplaced since extremely unusual 
weather, rain and low temperatures, dominated the 2007 DFW ozone 
season. The commenter continued that the first 100+ [deg]F temperature 
day was not reached until late August. The commenter concluded that EPA 
should not give TCEQ credit for something achieved only by the grace of 
God.
    Response (MC-9): We rely on the 2007 monitored air quality levels 
as part of our Weight of Evidence analysis. We investigated the 2007 
meteorology to determine how it compared with the DFW normal ozone 
season meteorology. To help account for all the different variables 
that impact the frequency of ozone we utilized a Meteorological 
Adjusted Trends analysis that was done by EPA personnel at Office of 
Air Quality Planning and Standards (OAQPS) for the DFW area to assess 
the ozone conduciveness of the 2007 ozone season. OAQPS's analysis 
utilizes temperature and precipitation data in addition to several 
other factors. The results of this analysis were included in our 
proposal, and indicated that overall 2007 was near the normal 
meteorology for DFW's ozone season. See Chapter 5, section 5.15 and 
Chapter 6, section 6.3 in the MOAAD TSD.
    The commenter asserts that the 2007 ozone season was biased low due 
to the influence of more rain than normal and less 100 [deg]F days than 
normal. EPA reviewed monthly meteorological National Climatic Data 
Center 2007 data for DFW International Airport (for the DFW ozone 
season months of March 1-October 31). We evaluated average monthly 
temperature, monthly average maximum temperature, and monthly 
precipitation. Looking at this temperature information and 
precipitation data, EPA's assessment is that, while for several months 
the precipitation was above average, the ozone season and the core 
ozone months (June-September) were near normal overall. For more 
information, see the Supplemental TSD. Ozone formation is affected by a 
number of

[[Page 1915]]

meteorological parameters and just looking at these three parameters 
does not give a complete evaluation of the ozone conduciveness of the 
2007 ozone season.
    The commenter was concerned that the meteorology was unusually 
nonconductive for generation of ozone exceedances in 2007. In light of 
this, EPA also reviewed ozone exceedance data for 2007, and found that 
the first exceedance occurred April 28th, and a number of exceedance 
days occurred starting in late July (7/24) and the last exceedance 
occurred on October 4th. In all, there were 12 days with exceedances at 
one or more monitors in the DFW area in 2007. This is below the long-
term normal trend of approximately 30 exceedance days per year. The 
limitation of just evaluating the number of exceedance days to 
determine if meteorology was normal or below normal is that exceedance 
days are a combination of meteorology and emissions. Emissions 
decreases due to fleet turnover among other things could also explain 
part or all of a lower than normal number of exceedance days in 2007.
    Finally, we note that one reason we evaluate attainment of a NAAQS 
based on three years of data is that use of several years tends to 
mitigate any unusual meteorology that occurs during a specific year. 
The year 2007 is the first of the three years of data (2007-2009) that 
will be used for determining if the DFW area reaches attainment in 
2009. The 2007 4th high maximums were all in the 80s ppb range or less 
for monitors that are typically near the area's design value. This is 
significantly lower than other recent years. Meteorological Trends 
analysis indicates that 2007 was closer to normal than 2005 and 2006. 
Therefore, the 2007 data is important from both a trends perspective as 
well as being the first of three years utilized in determining if the 
area reaches attainment in 2009.
    Comment (MC-10): The commenter indicated the DFW emissions 
inventory has gaps and that EPA knows that there are hundreds of 
industrial sources involved in the gas well drilling and gas pipeline 
operations that were not modeled by the TCEQ and which TCEQ assumed to 
be insignificant. The commenter asserted that without modeling these 
significant sources of NOX emissions, the attainment 
demonstration may be in greater jeopardy than EPA or TCEQ admits.
    Response (MC-10): The TCEQ projected the future emissions inventory 
for the industrial sources involved in the gas well drilling and gas 
pipeline operations with the most recent information available at the 
time of the emissions inventory development. Photochemical modeling is 
a very complex process and the emissions from natural gas production in 
the DFW area were rapidly changing during the last two years of 
modeling and SIP development and continue to do so. Improving emission 
estimates and projections is one of the elements of photochemical 
modeling that always requires an agency to balance the need to 
incorporate new information with the time available to complete the 
photochemical modeling tool for SIP development, and still meet the 
submittal deadline.
    TCEQ's basecase and future year (2009) SIP modeling did include 
estimates for emissions from industrial sources involved in gas well 
drilling and pipeline operations. During the commissioners meeting when 
the TCEQ adopted the DFW attainment demonstration SIP in May 2007, 
there were industry comments indicating emission estimates from natural 
gas compressor engines should be higher than were in the current 
modeling. Although the commissioners moved forward to adopt and timely 
submit the DFW 8-Hour Ozone attainment demonstration SIP, they also 
directed TCEQ staff to research the accuracy of the emissions 
inventories for these sources that were relied on in the attainment 
demonstration modeling. TCEQ staff subsequently conducted an additional 
survey to re-evaluate the number of stationary, gas-fired engines and 
other NOX emission sources that are common at natural gas 
production and gathering (P&G) facilities, in the nine-county DFW area. 
TCEQ provided that information to EPA as supplemental WOE in a letter 
dated April 23, 2008, which EPA has considered in its decision on 
whether to approve the attainment demonstration SIP. Details of this 
survey, the results, and explanation of how this information was 
utilized in EPA's review were included in the proposal package 
(Proposal FRN, MOAAD TSD, etc.).
    The survey collected data on existing NOX sources and 
expected additional installations by 2009 so that a comparison to 
estimated levels in the 2009 SIP modeling could be conducted. The 
survey also collected data on when the NOX emitting sources 
were installed. The survey indicated that P&G operations grew much more 
rapidly than projected in the SIP. Based on the survey results, TCEQ 
concluded that the majority of emissions growth would come from the 
increase in compressor engines and not from other facets of P&G 
operations. TCEQ therefore provided new estimates for the compressor 
engines' emissions growth.
    The survey indicated that almost all of the rapid growth that 
created the underestimation of additional engines and other related 
NOX sources from natural gas P&G emission sources had 
occurred after the 1999 base year. Fortunately, TCEQ put in place 
regulations that will control rich and lean burn natural gas fired 
compressor engines in the DFW area. TCEQ also controlled some engines 
involved with drilling operations in the Increment of Progress SIP.
    From the modeling perspective, using the new survey's results, the 
underestimation in the growth of emissions is greatly mitigated by 
TCEQ's implementation of NOX controls on emission sources in 
this industry group in Chapter 117 rules adopted as part of the May 30, 
2007 SIP submission. While mitigated to a large extent, the new survey 
data indicate that emissions in the demonstration modeling, i.e., the 
2009 Combo 10 modeling, from these natural gas P&G sources would add 
3.3 tpd based on our analysis of the TCEQ survey data. Using modeling 
sensitivity runs, we accounted for this approximate increase of 3.3 tpd 
in the projected emissions inventory, and we were able to estimate the 
effect on the modeled ozone levels. See Table 4 in the proposal. In 
considering the underestimation from a 'real world' standpoint, it is 
important to note that due to TCEQ's adopted regulations, a much larger 
amount of actual reductions of NOX emissions (estimated as 
35.7 tpd) will occur between 2007 and 2009 from the regulations on 
compressor engines and these extra reductions will help reduce DFW area 
ozone levels.
    While these emissions were not fully accounted for in the initial 
photochemical modeling, TCEQ had developed the emission inventory for 
this industry group consistent with EPA's guidance. EPA appreciates the 
additional survey information that TCEQ provided and, EPA considered 
the emissions in reviewing the attainment demonstration and found that 
TCEQ's revised emission estimates were acceptable. This information was 
clearly presented as part of the proposed rulemaking action and the 
commenter has not identified any substantive flaws with that analysis.
    Comment (MC-11): The commenter indicated that the emissions 
inventory appears flawed, in part from the observation that the latest 
VOC area source emissions inventory was unaffected despite the 
substantial revisions to the gas drilling/compressor engine count, as 
reflected in revised

[[Page 1916]]

NOX area source inventory revisions. The commenter further 
indicated that VOC emissions from the engine stacks, and fugitive 
emissions from the piping and valves that connect the engines, appear 
not to have been incorporated into the emissions inventory, and more 
importantly, not to have been considered in the photochemical modeling. 
The commenter asserted that the absence of these emissions in the 
revised inventory placed additional doubt on to the accuracy of the 
photochemical modeling to predict ozone levels in the western part of 
the nonattainment area.
    Response (MC-11): The commenter is correct that the VOCs from P&G 
facilities in the DFW area may be underestimated, since the number of 
P&G facilities and related NOX sources had a large 
underestimation. As provided above, there are inherent uncertainties 
with emissions inventories. Unlike the NOX emission 
discussed previously, however, the VOC emissions from natural gas 
production are largely compounds that are not significantly reactive in 
the formation of ozone. EPA defines ``Volatile Organic Compounds'' 
(VOCs) per 40 CFR Part 51.100(s) (as amended through January 18, 2007) 
and specifically lists Methane and Ethane as organic compounds that 
have been determined to have negligible photochemical reactivity. 
Methane and ethane are typically 85-90% or more of the compounds 
present in natural gas from gas wells so emissions from natural gas 
production would be expected to have a small impact on ozone 
production. In addition, modeling sensitivity analyses have shown that 
large reductions in all VOC emissions in the DFW area result in only 
very small changes in the area's ozone concentration level. Therefore, 
an underestimation of P&G VOC emissions would not change the Combo 10 
and PDMR 2009 modeling projections significantly. See Section 4.2 of 
ENVIRON's ``Ozone Benefits in DFW from Emission Controls in the 2009 
and 2012 Future Years,'' September 2006, included as a reference to 
Chapter 2 of the TCEQ TSD.
    TCEQ did not collect data on VOC sources in the 2007 survey that 
they conducted of natural gas P&G facilities in the DFW area. TCEQ 
focused on NOX emission sources in their survey since 
numerous photochemical modeling analyses had shown that elevated ozone 
levels in the DFW area were much more sensitive to changes in 
NOX emissions than VOC emissions. For these same reasons, 
EPA does not believe that uncertainty in the natural gas P&G VOC 
emissions would result in a significant change in modeling projections 
or change our conclusion that the DFW area will attain the 1997 ozone 
standard by its attainment date.
    Comment (MC-12): The commenter indicated that the Base Case 
Monitoring Data is skewed because it relies on the 1999 episode and, 
focusing on the Frisco Monitor, misrepresents the greater and more 
current problems associated with monitoring data from monitoring 
stations to the northwest and west. The commenter continued that the 
use of this 10-year old base case set results in under-emphasis of the 
effect of the numerous sources, including the Ellis County cement 
kilns, Barnett Shale natural gas and oil drilling, and EGU's to the 
south of the metroplex which often have their plume carried in 
southeasterly winds into Tarrant County. The commenter asserted that 
the 1999 data set is flawed due to the unusual meteorological 
conditions as well as its overall lack of representativeness and that 
Texas must be directed to develop additional base case data sets for 
SIP planning efforts.
    Response (MC-12): EPA does not agree with the commenters' 
assertions for several reasons. As discussed in Section 2.3 of EPA's 
MOAAD TSD, EPA reviewed this 1999 episode and found it to be acceptable 
and representative of the combination of meteorology and emissions that 
generate ozone exceedance levels near the DV of the area at the time 
episodes were being selected for development of this SIP. The 2009 
modeling projections evaluate ozone levels at all the monitors in the 
DFW area and, for this episode, both the Denton and Frisco monitors had 
the highest FDVs; therefore, the emphasis was not just on the Frisco 
monitor as the commenter asserts.
    Photochemical grid modeling takes several years to develop and 
thus, at the time of submittal of a SIP, the episodes are typically 
several years old. Selection of episodes to model for SIP planning is a 
balance of finding historical periods with several days of exceedances 
that are representative of the conditions that generate ozone near the 
design value for the area and developing acceptable base case modeling 
in time to allow for a timely submittal of an attainment demonstration. 
At the time that TCEQ proposed the DFW attainment demonstration SIP in 
December 2006, the episode was just over 7 years old, not 10 years old 
as the commenter indicated.
    Chapter 2 of the MOAAD TSD included sections that detailed EPA's 
guidance on episode selection, how the episode was originally chosen 
and further discussion and review that occurred in 2005 about the 
adequacy of this episode and the potential benefits of other episodes 
The DFW area monitors that have been DV monitors or had values near the 
area's DV for the period 1999-2005 (the period that was reviewed for 
potential episodes was 1998-2004) indicates that all of these monitors 
have been either north of the DFW area (Frisco monitor) or in the 
northwest sector (Tarrant and Denton Counties monitors). EPA has done a 
detailed review of both TCEQ's analyses and EPA's analyses of the 
conceptual model for high ozone in DFW and what monitors are the DV 
monitors. In years when light winds are more predominantly from the 
south, the northern monitors (Denton and Frisco) are the DV monitors. 
Other years, the winds and frequency of light winds are predominantly 
from the southeast, resulting in the Tarrant and Denton Counties 
monitors becoming the DV monitors. The location of the DFW area's DV 
monitor depends on the distribution of the frequency of wind directions 
during ozone conducive meteorology, but it is consistently on the 
downwind side of the DFW area. In fact, assuming the preliminary 
monitoring data through October 31, 2008 does not change, the Denton 
monitor will be the DV monitor for the 2006-2008 period. Preliminary 
data also indicate that the Denton monitor may be the DV monitor for 
the period 2007-2009 (based on 2007 and 2008 monitoring data). 
Approximately 70% of the local NOX emissions that lead to 
high ozone levels are emitted from mobile (On-Road and Nonroad emission 
sources) and the highest ozone levels typically occur downwind of the 
core DFW emissions area. Figures 3 & 5 of TCEQ's Appendix B of their 
SIP submittal illustrate the distribution of NOX emissions 
from On-Road and Nonroad emissions. Modeling, monitoring, and aircraft 
flights confirm that the highest levels of ozone occur downwind of the 
core DFW emissions area. As discussed above, the Frisco and Denton 
monitors are often downwind of the core DFW emissions area. Therefore, 
EPA does not agree that this episode, the control strategy, and the SIP 
overall are biased by the Frisco monitor being one of the highest ozone 
monitors in the base year.
    The commenter asserted that using the 1999 episode results in 
under-emphasis of the effect of the numerous sources, including the 
Ellis County cement kilns, Barnett Shale natural gas and oil drilling, 
and EGU's to the south of the DFW metroplex which often have their 
plume carried in southeasterly

[[Page 1917]]

winds into Tarrant County. As discussed elsewhere in this response and 
in EPA's MOAAD TSD, EPA conducted a thorough review of EPA's episode 
selection guidance, conceptual model for high ozone events in DFW, and 
episodes available for modeling at the time of episode selection and 
EPA determined that this episode was appropriate and acceptable. EPA 
does not recommend episode selection be based on trying to target 
specific industry/emission sources but should weigh a number of factors 
in selecting episodes for photochemical grid modeling to be utilized 
for SIP development as was done in this situation.
    Afternoon wind from the southeast is one of the more prevalent wind 
directions for high ozone in the DFW area. In TCEQ's conceptual model 
description for high ozone events in the DFW area, morning winds out of 
the south or southwest often occur and then transition to out of the 
southeast or east in the afternoon. Therefore, the sources mentioned 
can impact the Denton and Frisco monitors for some of the hours of the 
day (that contribute to a high 8-hour ozone value). This episode has 
two days with winds from the southeast in the afternoon (8/17 and 8/
22). August 17th had winds out of the southwest in the morning that 
transitioned to winds out of the southeast in the afternoon. Forward 
wind trajectories for the 17th indicate the emissions from the Ellis 
County cement kilns were carried over the Frisco and Denton monitors. 
On the 17th, it is also likely that emissions from the other sources 
mentioned would also be carried over the Denton and potentially Frisco 
monitors. Even on days that the winds do not take emissions from these 
sources over the Frisco and Denton monitors, the modeling still 
utilizes these emissions (and changes in these emissions) in projecting 
ozone levels in the modeling domain. Among modeling analyses that can 
be impacted by emission reductions at these sources are changes in 
ozone exceedance metrics, such as number of grid cell 8-hour ozone 
exceedances predicted and other metrics that consider the level of 
exceedances predicted for each grid cell.
    In summary, EPA has reviewed the episode and determined that the 
episode is representative of the conditions most often associated with 
high eight-hour ozone in the DFW area.
    Comment (MC-13): Commenters indicated that the future case 
attainment demonstration modeling included NOX reductions 
from Phase I Clean Air Interstate Rule (CAIR) controls for EGUs outside 
of Texas. Commenters indicated that since these reductions are now 
unlikely to occur, at least on the original timeframe, the anticipated 
ozone air quality benefits will be reduced. Commenters asserted that 
EPA should consider this effect on the modeling and the WOE analysis.
    Response (MC-13): The EPA has considered the impact of a CAIR 
vacatur and determined that even an immediate vacatur of CAIR would not 
change our conclusion that the modeling and weight of evidence show 
that the DFW area will attain the 1997 8-hour ozone standard by the 
deadline. The principal reasons for this conclusion are: (1) Chapter 
117 rules in the Texas SIP implemented in the entire eastern half of 
Texas are equivalent to the Phase I rules of CAIR; (2) evaluation of 
controls already installed in the nearest States impacted by CAIR, 
Arkansas and Louisiana, show that significant reductions will still be 
implemented; (3) many of the more distant states impacted by the CAIR 
vacatur are also subject to the NOX SIP call so much of CAIR 
Phase I NOX reductions will remain in place; and (4) 
available modeling shows that loss of CAIR only has a small impact on 
the DFW area.
    Texas implemented NOX controls on EGUs in the entire 
eastern half of Texas that are approved into the Texas SIP, are 
enforceable, and are equivalent to reductions from CAIR Phase I for 
East Texas EGUs. The rules can be found in Texas Administrative Code 
Title 30 Part 1 Chapter 117 Subchapter E Division 1 (117.3000-
117.3056). Therefore, the level of NOX reductions from EGUs 
within the entire eastern half of Texas for the 2009 period is not 
related to the status of the CAIR rules. With regard to EGU emissions 
in the western half of Texas, EPA has concluded that emissions from 
these sources would rarely be transported to the DFW area during 
periods of high ozone in DFW. Thus, any changes in emissions from Texas 
EGUs related to a vacatur of CAIR are not expected to impact DFW ozone 
exceedance levels prior to the attainment date.
    In fact, the main change in emissions in the DFW photochemical 
modeling domain due to a CAIR vacatur is for CAIR states that were not 
part of the NOX SIP call and were outside of Texas. Of these 
states, Louisiana and Arkansas are the closest upwind states to DFW and 
would be expected to have the largest potential impact on ozone level 
changes in DFW due to the CAIR vacatur. We have reviewed EPA's Clean 
Air Market's Division National Electric Energy Data System database 
(July 2008 version) that tracks equipment that has been installed to 
meet the CAIR requirements for the EGUs in these two states. Our 
evaluation of controls installed at facilities in Arkansas and 
Louisiana considered whether installed controls were integral to 
operation of the unit (example: Low NOX Burners), or if the 
controls could be shut-off (Example: Over-fire Air) or potentially 
bypassed (SCR). We have also conferred with Louisiana and Arkansas 
Departments of Environmental Quality in an attempt to confirm the 
information in the database.
    Our analysis of Louisiana major EGU's indicates that most controls 
are based on Over-Fire Air or SCR (based on discussions with LDEQ 
(September/October 2008)). However, the Dolette Hills is the closest 
large Louisiana coal-fired EGU that is outside Texas and has the 
highest potential to impact DFW area ozone levels of any coal-fired EGU 
outside of Texas. It is often upwind of the DFW area when the DFW area 
has elevated ozone levels. Low NOX burners and Over-Fire air 
have been installed at the Dolette Hills unit to reduce NOX 
emissions. In the absence of CAIR, it is possible that the utilization 
of Over-Fire air could cease, but the Low NOX burners are 
integral to the boiler operation and cannot be bypassed. Therefore, 
even if the Over-Fire Air were not operated there would still be 
permanent large NOX reductions on the order of 2000 to 3000 
tpy of NOX (based on Discussions with LDEQ) compared to 4000 
to 5000 tpy of NOX with Over-Fire Air and Low NOX 
Burners.
    Our analysis of EGUs in Arkansas indicates that for the coal-fired 
EGU's, most are being controlled with Over-Fire Air, but one 523 MW 
unit is being controlled with Low NOX burners that have been 
installed and should remain installed. For the gas-fired EGUs, most are 
being controlled with Dry Low NOX burners in combination 
with SCR. The Low NOX Burners are integral to the operation. 
The SCR, however, conceivably could be turned off. Dry Low 
NOX burners can achieve up to a 30% reduction by themselves 
so significant reductions will still occur.
    Therefore, even with a vacatur of CAIR, significant reductions will 
still occur in Arkansas and Louisiana including at the closest, upwind 
plant, Dolette Hills. As for the reductions in other States impacted by 
a CAIR vacatur, many of these States were part of the NOX 
SIP call. The NOX SIP call reduction requirements remain in 
place. States affected by the NOX SIP call include: Alabama, 
Connecticut, Delaware, Georgia, Illinois, Indiana, Kentucky, Maryland, 
Maine, Michigan, Missouri, New Jersey, New York, North Carolina, Ohio, 
Pennsylvania, Rhode

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Island, South Carolina, Tennessee, Virginia, West Virginia and the 
District of Columbia. While some states' rules implementing the 
NOX Budget Trading Program (established by the 
NOX SIP call) have a sunset provision in anticipation of 
being replaced by the CAIR ozone-season trading program, EPA expects 
the majority of controls to remain in place. EPA has asked States with 
sunset provisions to move quickly to address this concern.
    We believe that it is reasonable to consider that the reductions 
identified above will occur because the previously installed controls 
are integral to the operation of the EGUs and are not likely to be 
bypassed or circumvented or are required to comply with regulations 
implementing the NOX SIP call.
    EPA also considered available modeling evidence in considering the 
impact of a CAIR vacatur. First, the photochemical modeling upon which 
the CAIR rule itself was based did not result in any other State being 
included in the CAIR rules because of its impact on the DFW area. In 
other words, no state was included in CAIR because of its impact on the 
DFW area.
    No modeling exists that directly evaluates the impact of a CAIR 
vacatur on the modeling episodes used in the final DFW SIP modeling so 
it is not possible to directly evaluate the impact on Combo 10 or PDMR 
2009 control strategy runs. EPA has found two modeling analyses that 
help to evaluate the potential impact of the CAIR vacatur on DFW ozone 
levels.
    We also have reviewed sensitivity modeling that evaluated potential 
CAIR impacts conducted on an earlier version of DFW modeling. This 
modeling was included in the HARC 35 Project Phase II Report (``Dallas/
Fort Worth CAMx Modeling: Improved Model Performance and Transport 
Assessment Project H35, Phase 2''; ENVIRON; August 2005). The H35 Phase 
II report evaluated the impact of the CAIR emission reductions 
throughout the Eastern U.S. on DFW ozone levels in 2010. The report 
included a bar chart (Figure 10-4), showing episode average 
contributions to high 8-hour ozone in the DFW 9-county NAA by source 
region and emissions group. Side-by-side bars show the subtle changes 
due to the CAIR EGU controls. Controls expected from CAIR reduced 
episode average high ozone in the DFW NAA by 0.3 ppb. The episode peak 
ozone was also lowered 0.3 ppb over DFW from the CAIR controls. This 
early modeling did not include some of the later emission inventory and 
meteorological refinements, but a new evaluation with the modeling 
submitted with the attainment demonstration would not be expected to 
yield significantly differing results.
    We also looked at some earlier modeling that was included in Table 
4-1 of the H35 Phase I Report (HARC Project H35, Transport 
Contributions From Out-of-State Sources to East Texas Ozone, February 
2005). The H35 Phase I report indicated that controlling a 25% 
NOX reduction on all EGUs in Arkansas, Louisiana, 
Mississippi, Missouri (NOX SIP call state), Oklahoma (non-
CAIR state), Tennessee (NOX SIP call state), and the Gulf of 
Mexico (non-CAIR area) yielded a 0.1 ppb reduction in ozone on average 
2007 elevated ozone levels (evaluated levels above 75 ppb and 85 ppb) 
in DFW area for the DFW's SIP episode. While this analysis is for 2007 
and conservatively includes 25% NOX reductions in two 
NOX SIP call states, 25% reductions in Oklahoma (non-CAIR 
state), and 25% reductions in Gulf of Mexico EGUs; all of which are 
additional reductions not related to the CAIR Phase I rule. The 2007 
modeling analysis is further evidence that the DFW area is not 
influenced by out-of-state EGU emissions at times when elevated ozone 
levels occur in DFW.
    Both of these modeling analyses consistently show a picture that 
out of state reductions only have a small impact of 0.1 to 0.3 ppb or 
less on model projected design values in the DFW area. The two CAIR 
assessment analyses (EPA--Fall 2008 and H35 Phase II) are conservative 
because they remove all CAIR reductions from the modeling. This does 
not take into account that for non-NOX SIP call states, some 
CAIR controls will generate reductions because the controls are 
integral to the combustion process and will not likely be removed (Low 
NOX Burners, etc.). These two CAIR modeling analyses also 
rely on 2010 EGU projections, which include an additional year of EGU 
growth, compared to the growth that would be included for a 2009 
evaluation. These modeling evaluations over predict for NOX 
during the 2009 ozone season because many states will still have in 
place NOX controls required by the NOX SIP call.
    The worst-case assessment of a 0.1 to 0.3 ppb increase on model 
projected FDVs, in itself, is small enough that for most model 
projections, no change in the truncated ppb value would occur. Given 
that the actual impact of a vacatur on emissions would be smaller than 
in these worst case analyses, EPA believes that the status of the CAIR 
rules should not impact our decision to approve the DFW attainment 
plan.
    We have included further discussions of a vacatur of CAIR on the 
modeling and WOE analysis in a separate response to comment that 
addresses comments on the adequacy of the WOE analysis and the 
conclusion of whether the DFW NAA will reach attainment.
    Comment (MC-14): The commenter indicated that the DFW attainment 
demonstration model has considerable challenges as detailed in the 
Notice of Proposed Rulemaking. The commenter noted that model 
development is a resource intensive process and the state simply needs 
to apply additional resources to this process. The commenter stated 
that throughout the development of the May 2007 SIP revision, the State 
indicated that it had insufficient resources to improve the attainment 
demonstration and incorporate alternative and more recent ozone 
episodes. The commenter concluded that the State has not allocated 
adequate resources to SIP development, including model development, to 
develop models robust enough to accurately predict ozone concentrations 
in the attainment year and beyond. The commenter then concluded that as 
part of any final action, EPA should advise the state that failures to 
program sufficient resources to meet CAA requirements in the future 
will not be accepted as justification of inadequate or incomplete 
demonstrations of attainment.
    Response (MC-14): All states and other entities that conduct 
photochemical modeling must address competing priorities and determine 
whether additional work will provide significant additional value. They 
must consider several factors including the time available for 
completion of modeling of episode(s), updating of emissions 
inventories, the resources needed to conduct further refinements or 
additional episodes, and the overall benefit of delaying the project to 
conduct additional modeling work.
    The commenter is correct that modeling is a very resource intensive 
process. Photochemical modeling requires creation of very detailed 
emission inventories and meteorological modeling to be used in 
photochemical modeling in an attempt to replicate a historical event 
when ozone exceedances have occurred. Once photochemical modeling has 
been created that performs sufficiently well, the basecase modeling can 
then be used in conjunction with future case modeling of the same 
meteorological conditions to test attainment demonstration strategies. 
It often takes many iterations of refinement of emissions and/or 
meteorological fields to result in basecase photochemical modeling that 
performs sufficiently in

[[Page 1919]]

accordance with TCEQ's meteorological performance metrics and EPA model 
performance metrics.
    As discussed in the proposal and the MOAAD TSD, TCEQ did consider 
and complete exploratory work on other episodes. But initial analyses 
indicated that the additional episodes would not give significantly 
different results compared to the existing episode. As we explain in 
Section 2.3 of the TSD, we believe in this case, the one episode is 
acceptable for control strategy development. EPA evaluated the 
preliminary analyses of other episodes and concurred that it did not 
appear that the additional episodes would alter the model projections 
on what was needed to reach attainment.
    EPA believes that the episode selection is appropriate, and that 
the modeling was sufficiently robust. The demonstration modeling 
combined with the WOE analyses are sufficient to show that the DFW area 
will attain by the deadline.
    Comment (MC-15): Commenters indicated that the DFW 8-hr ozone SIP 
proposal by TCEQ is significantly flawed and fails to support the 
required attainment demonstration by 2010. Commenters continued that 
the DFW modeling by TCEQ shows that several ozone monitors in 2010 will 
still exceed the rounded-up standard of 84 ppb. A commenter asserts 
that the CAA requires that SIPs show clear attainment for all ozone 
monitors in a nonattainment area and the reason that the air modeling 
shows exceedances in 2010 is because the proposed reductions by TCEQ 
are inadequate.
    Commenters also indicated that according to Table 5 of the Federal 
Register notice, TCEQ's plan predicts that 2 monitors in the region 
would not meet the 8-hour ozone NAAQS after implementation of the 
control strategy (PDMR 2009) and consideration of TCEQ's Weight of 
Evidence. Commenters continued that they are aware that EPA's ozone 
implementation guidance allows a ``Weight of Evidence'' demonstration 
to supplement the modeling analysis required by the CAA but assert that 
this analysis fails to overcome the inadequacy of the TCEQ's proposed 
control strategy to bring the DFW area into attainment.
    Commenters indicated that the proposal establishes repeatedly that 
ambient air quality is likely to remain above the artificial rounded-up 
standard of 84 ppb (Tables 2, 3 and 5). The commenters went on to 
assert that after disclosing that state WOE calculations fall short of 
meeting the attainment goal, EPA ultimately relies on their 
``simplistic'' analysis concluding that 15% of the NOX 
emissions inventory will be reduced by existing measures not present in 
2007. The commenters continued that given the degree to which design 
values have to fall, from 95 ppb to 84 ppb, and in light of the 2010 
attainment date, EPA should consider that the drop in the 
NOX and VOC emissions inventories from 2007 to 2009 are 
completely insufficient, according to EPA's own studies and guidance, 
to bring about the drop in DVs needed to reach attainment. The 
commenters further continued that EPA's own analysis of the most recent 
TCEQ modeling shows that the State was only able to get all the area's 
predicted DVs below 88 ppb with a non-standard and non-approved 
calculation of RRF factors and EPA's own analysis with the proper RRF 
procedure showed that monitors were still above the 88 ppb threshold.
    A commenter indicated that the WOE approach by the TCEQ is flawed 
since it fails to show attainment by 2010 and EPA needs to reject it as 
bad science.
    Response (MC-15): We responded to comments on the TCEQ and EPA RRF 
methods in a separate response to comments above. Overall, EPA 
considered both RRF methods and the results of those methods in our 
review. Also, as explained in previous responses, we considered the 
results of modeling from both Combo 10 and PDMR 2009 modeling runs.
    EPA disagrees with the commenter that the modeling alone must 
demonstrate attainment in order for EPA to approve the attainment 
demonstration. EPA discussed both in the DFW MOAAD TSD and the 
proposal, EPA's guidance on modeling and WOE usage. As with any 
predictive tool, there are inherent uncertainties associated with 
photochemical modeling (emission estimates, emission projections, 
meteorological modeling, chemical reaction equations and 
simplifications, etc.). 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. This was further 
updated in 2005 and 2007 for the 1997 8-hour ozone attainment 
demonstration procedures to include a WOE analysis as an integral part 
of any attainment demonstration due to concerns of modeling 
uncertainties. This guidance strongly recommends that all attainment 
demonstrations include supplemental analyses beyond the recommended 
modeling. These supplemental analyses should provide additional 
information such as monitoring data analyses, and emissions and air 
quality trends, which help corroborate the overall conclusion from the 
photochemical modeling. EPA's modeling guidance specifically recommends 
that a WOE analysis be included as part of any attainment demonstration 
SIP where the modeling results predict FDVs ranging from 82 to less 
than 88 ppb (EPA's 2005 and 2007 A.D. guidance documents). It is 
important to note that EPA recommends a WOE analysis even if the 
modeling is demonstrating attainment at all the monitors. 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).
    In this case, the commenters are correct that the final modeling 
based projections show two monitors above attainment levels. Prior to 
conducting the model based projections, the highest modeling values 
were 88/89 ppb (TCEQ/EPA RRF method), but after modeling based 
adjustments were conducted to account for reduced airport emissions, 
DERC usage limitations, and back-up generator reductions, the highest 
value using either RRF was 88 ppb. EPA specifically recommends a WOE 
analysis be performed when modeling values are within the range 
indicated by the DFW analysis.\11\
---------------------------------------------------------------------------

    \11\ The modeling guidance does not specifically preclude the 
use of WOE when the modeled values are higher than the recommended 
WOE range.
---------------------------------------------------------------------------

    EPA's guidance (2005 A.D. Guidance) does indicate that a local 30% 
NOX reduction may only yield a 3-4 ppb change in modeling 
values. That assessment was based on coarser resolution photochemical 
modeling that is typically less responsive to emission changes than the 
finer grid modeling that was used in DFW. Here, EPA is relying on 
analyses that were done employing the DFW modeling to determine the 
potential change in ozone due to the additional NOX 
reductions that are estimated to occur by 2009. Relying on these DFW 
analyses, EPA estimates that the 25.4% local DFW area NOX 
reductions occurring between 2007 and 2009 would reduce ozone 
concentrations by approximately 3-4 ppb. As discussed in detail below, 
EPA is considering much more than just the modeling in making our 
conclusions on the adequacy of the attainment demonstration and 
determining that the 2005-2007 DV of 95 ppb will drop to attainment 
levels (84 ppb) in 2009.

[[Page 1920]]

    EPA evaluated many factors in the WOE. These items include 
reductions not included in the modeling based projections (energy 
efficiencies), unquantifiable measures (AirCheckTexas, Dallas 
Sustainable Skyline Initiative, etc.), meteorological analyses of 
severity of ozone seasons (the base period and recent years, including 
2007), most recent monitoring in 2007 (a 4th high of 89 ppb at two 
monitors and the other 18 monitors had 4th high values of 87 ppb or 
less), the court's vacatur of CAIR, progress in implementing the TERP 
program, and progress in implementing the early compliance incentive on 
natural gas compressor engines outside the DFW area. The amount of 
NOX reductions quantified in the SIP from the 2007 period 
that are estimated to occur by 2009 are approximately 15% of the 
estimated 2007 EI; these reductions will come from the existing 
federal, state, and local measures. When one includes the additional 
reductions due to the underestimation of emission reductions from 
compressor engines, the backup generators, and the State's progress in 
implementing TERP, there would be a 25.4% reduction in NOX 
emissions between 2007 and 2009, which could yield approximately a 3-4 
ppb drop in ozone based on modeling projections.
    In a response above, we concluded that 2007 had meteorology similar 
to normal meteorology. We also examined whether the 2008 data indicates 
a trend toward attainment for the area. We examined the 2008 
preliminary data, which is awaiting QA/QC. The 2008 preliminary data 
show that the DFW area had 4th high values of 85 ppb at two monitors 
and at the other 18 monitors, the value was 84 ppb or less. The 2008 
preliminary data indicate the 2006-2008 DV is 91 ppb (down from 95 ppb 
in using 2005-2007 monitoring data). For the monitor that has the 
highest average 4th high values in 2007 and 2008 and is likely to be 
the controlling monitor (or one of the highest monitors) for 
determining if the area reaches attainment based on 2007-2009 data, the 
monitor's DV for the 2007-2009 period would have to be less than 85 
ppb. It is important to note that this monitor (Denton) had a 
preliminary 4th high value in 2008 of 84 ppb. Considering the 2008 
preliminary data with most of the 4th highs of 84 ppb or less, and that 
much of the DFW SIP reductions and another year of fleet turnover are 
still to occur, the ambient air quality trend strongly supports that 
the DFW monitors will reach attainment in 2009. EPA believes that the 
closer an area is to its attainment date, the more weight should be 
given to the actual ambient data and the expected additional reductions 
in considering whether an area will reach attainment.
    We have considered modeling using two emission reduction scenarios 
(Combo 10 and PDMR 2009), recognizing that the actual emission control 
level would be somewhere in between, and two types of RRF calculations. 
We have also considered the impact of additional measures and 
reductions documented in the April 23, 2008 letter. With these 
adjustments, the modeling is demonstrating 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, after evaluating additional evidence 
in a WOE analysis, that the area will attain by its attainment date. 
Specifically, we 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 due to 
the emission reductions achieved by local and regional rules. We 
considered the impact of meteorological adjustments to the design value 
projection, which would further indicate the future projections may be 
too high. We have recognized emission reduction efforts that have not 
been quantified and included in the modeling and model-based WOE 
estimates. We also considered and gave significant weight to non-
modeling evidence of recent monitoring and projected NOX 
emission changes between 2007 and 2009.
    We have also considered ambient data in 2008 and progress in 
implementing control measures in making our final conclusion on the DFW 
area's 8-hour Ozone SIP's Attainment Demonstration adequacy. For 
example, we weighed a vacatur of the CAIR rules and its potential 
impact on the DFW area. As discussed in detail in a response above, we 
concluded that the removal of CAIR may result in a change in 8-hour 
ozone modeling values of 0.1-0.3 ppb. We also considered that fewer 
engine controls were installed using the early compliance incentive 
money that was available.
    We have also considered the progress in implementing the TERP 
program. This program has achieved all of the reductions that were 
projected in the May 30, 2007 submissions. These reductions were 
included in the modeling. In its April 2008 letter, Texas indicated 
that an additional 14.2 tpd of emission reductions could be achieved 
through the additional funding made available by the legislature. EPA 
relied on this projection as part of our weight of evidence evaluation 
in our proposal. As discussed in the response to comments on the TERP 
reductions, since our proposal notice, additional information has 
become available on the status of TERP projects and the State's 
progress in meeting its WOE projection of 14.2 tpd of NOX 
emissions reductions in 2008 and early 2009. Recently TCEQ announced 
they would be delaying the 2009 TERP grant application cycle, due to 
Hurricane Ike. Due to this unfortunate delay (the grant application 
cycle opened December 1, 2008), FY2009 grant money will be issued later 
than originally thought. Approval of grants will not likely occur by 
the beginning of the DFW ozone season (March 1, 2009), but approval of 
grants should start in the May to early June timeframe. While this is 
not by the beginning of the ozone season, it is soon enough that 
reductions could start occurring before the core ozone season and 
therefore additional reductions can be considered as weight of 
evidence.
    This is confirmed by an examination of 2004-2007 and preliminary 
2008 monitoring values for the typical design value monitors (north and 
northwest sides of the DFW area) which is included in the supplemental 
TSD. It shows that the 1st to 4th high 8-hour ozone values (values that 
are utilized in setting the area's DV) are usually set in the June 
through September timeframe.
    Since the approval of FY2009 grants should start before or during 
the beginning of the core ozone period for the DFW area, some 
additional reductions can be considered as WOE. At this point, it seems 
unlikely that the full 14.2 tpd will be achieved even by the core ozone 
season. To evaluate the impact, we assumed that TCEQ would achieve 
approximately 70% of the originally projected 14.2 tpd; consequently, 
there might be a loss in reductions of approximately 4.2 tpd. See the 
Supplemental TSD. Then in looking at the modeling based WOE, the 
increase in projected NOX would yield approximately an 
additional 0.10 to 0.22 ppb at the monitors with the highest FDVs. We 
have also revised our estimate of actual reductions between 2007 and 
2009 to consider this potential loss in TERP emission reductions. 
Rather than the 26% we considered at proposal, our new estimate is a 
25.4% reduction of the estimated 2007 emission levels.
    Finally, over half of the previously discussed 25.4% reductions of 
NOX emissions (between 2007 and 2009) in the DFW area are 
slated to occur between the 2008 and 2009 ozone seasons. Due to these 
large local

[[Page 1921]]

reductions, we expect the 2009 ozone levels to be lower than 2008 
levels.
    In summary, EPA has considered a number of factors. As pointed out 
by commenters, some control strategies, notably CAIR and TERP, are 
likely not going to achieve the reductions originally expected. As 
discussed above, we considered the impact of these factors to be 
relatively small. We believe that at this time, with the attainment 
date only months away, we should give considerable weight to the recent 
air quality trends and to expected further reductions that will occur 
before the 2009 core ozone season. Therefore, considering all of the 
factors discussed above with the elements we considered in the proposal 
(available modeling, evidence, analyses, and adopted control 
strategies) and the comments we received, EPA believes the DFW area 
will reach attainment of the 1997 8-hour ozone standard by its 
attainment date.

E. Comments on Discrete Emission Reduction Credits (DERCs)

    Comment: A commenter states that EPA's conditional approval of the 
DFW attainment demonstration does not provide for adequate public 
review and comment on the measures TCEQ has committed to implement. The 
commenter is concerned that the public will not have the opportunity to 
review and comment on the DERC flow control limit.
    Response: Section 110(k)(4) of the Act authorizes conditional 
approval of ``a plan revision based on a commitment of the State to 
adopt specific enforceable measures by a date certain, but not later 
than 1 year after the date of approval of the plan revision.'' 
Conditional approval is authorized when a SIP contains substantive, but 
not fully satisfactory, provisions, and the State commits to submit 
specific enforceable measures to cure the deficiencies. We have 
proposed to conditionally approve the DFW attainment demonstration 
conditioned on the TCEQ submitting a complete SIP revision by March 1, 
2009, that includes an enforceable mechanism providing a 3.2 tpd 
restriction on the amount of DERCs available for use in the DFW area 
starting March 1, 2009. If the State wishes to use more than 3.2 tpd of 
DERCs in the DFW area after 2009, there must be an enforceable 
mechanism that provides for increases above 3.2 tpd beginning January 
1, 2010 as long as this increase is consistent with attainment and 
maintenance of the standard.
    Section 110(a)(2) of the Act and 40 CFR Part 51 require the State 
to conduct a 30-day public comment period and hold a public hearing on 
a proposed SIP revision submittal. Further, the State must include in 
the adopted SIP revision submittal a response to all the received 
comments. The TCEQ has proceeded with a proposed rulemaking and held a 
public comment period, pursuant to the requirements of the Act and 40 
CFR Part 51, from August 6 through September 12, 2008, on the proposed 
DERC SIP revision to meet the condition. Additionally, the State 
published the proposal in the Texas Register and held public hearings 
on September 9, 2008, in Dallas, Texas and on September 10, 2008, in 
Arlington, Texas. EPA and others provided comments.
    Upon receipt from the TCEQ of a complete DERC SIP revision, EPA 
will review it and propose action in the Federal Register. In this 
notice, we will provide, as required by the Act, an opportunity for a 
30-day public comment period.
    The public is provided with three separate opportunities to review 
and comment on the DERC SIP revision--during (1) the comment period for 
EPA's proposed conditional approval of the DFW attainment 
demonstration; (2) the comment period for the State's proposed 
rulemaking; and (3) the comment period for EPA's proposed action on the 
DERC SIP revision. Thus, EPA finds that there are ample opportunities 
for public review and comment on the DERC SIP revision.
    Comment: A commenter states that EPA's conditional approval of the 
DFW attainment demonstration relies upon the DERC rule; yet EPA has 
only conditionally approved the DERC rule into the Texas SIP. The 
commenter states that emission credits subject to the DERC rule should 
not be relied upon as part of the attainment demonstration SIP until 
EPA fully approves the DERC rule.
    Response: As noted in the previous response, the Act authorizes 
conditional approval based on a State's commitment to adopt specific 
enforceable measures by a date certain. If the State fulfills its 
commitment with respect to the DERC flow control limit and EPA approves 
the submission, we believe the attainment demonstration will include 
all enforceable measures necessary to attain by the attainment date. 
The attainment demonstration cannot be fully approved until the State 
submits and EPA approves the revision to the DERC rule providing for 
the 3.2 TPD flow control limit. In the interim, as provided in the Act, 
the plan may be conditionally approved with a commitment to submit the 
necessary DERC rule revision.
    As the commenter notes, the DERC rule is already conditionally 
approved (see 71 FR 52703, September 6, 2006). In our final conditional 
approval of the DERC rule, we stated that a conditional approval is 
treated as a full approval until such time that EPA takes action to 
disapprove the rule. Therefore, it is acceptable for TCEQ to continue 
allowing DERCs to be used within the DFW nonattainment area.
    Further, the terms of the 2006 DERC conditional approval do not 
directly impact the DFW attainment demonstration and its DERC flow 
control condition. TCEQ committed to making the following revisions to 
the DERC rule in their September 8, 2005, commitment letter and to 
comply with these commitments during the 2006 DERCs conditional 
approval period:
    1. Revise Title 30 Texas Administrative Code (30 TAC) Sec.  101.373 
to prohibit the future generation of DERCs from permanent shutdowns and 
to allow DERCs generated and banked from permanent shutdowns prior to 
September 30, 2002, to remain available for use for no more than five 
years from the date of this letter.
    2. The TCEQ will perform a credit audit to remove from the 
emissions bank all DERCs generated from permanent shutdowns after 
September 30, 2002. Even if the shutdown itself occurred before 
September 30, 2002, no DERCs can be generated from that event after 
September 30, 2002.
    3. Revise 30 TAC Sec. Sec.  101.302(f), 101.372(f)(7) and 
101.372(f)(8) to clarify that EPA approval is required for individual 
transactions involving emission reductions generated in another state 
or nation, as well as those transactions from one nonattainment area to 
another, or from attainment counties into nonattainment areas. The TCEQ 
further understands that the EPA would require a SIP revision prior to 
approving a transaction between another state or nation, as well as 
those transactions between counties not located within the same 
nonattainment area.
    4. The TCEQ will revise Form DEC-1, Notice of Generation and 
Generator Certification of Discrete Emission Credits; Form MDEC-1, 
Notice of Generation and Generator Certification of Mobile Discrete 
Emission Credits; and Form DEC-2, Notice of Intent to Use Discrete 
Emission Credits, to include a waiver to the federal statute of 
limitations defense for generators, and users of DERCs and mobile 
discrete emission reduction credits (MDERCs). Please be reminded that 
there is currently no applicable state statute of limitations in the 
State of Texas. In addition, the TCEQ will maintain its current policy 
of preserving all records relating to DERC and MDERC generation

[[Page 1922]]

and use for a minimum of five years after the use strategy has ended.
    5. Revise 30 TAC Sec. Sec.  101.302 and 101.372 to clarify that a 
proposed quantification protocol may not be used if the TCEQ Executive 
Director receives a letter from the EPA objecting to the use of the 
protocol during the 45-day adequacy review period or if the EPA 
proposes disapproval of the protocol in the Federal Register.
    6. Revise 30 TAC Sec.  101.306 to specify that Emission Reduction 
Credits may be used within the highly reactive volatile organic 
compounds Emissions Cap and Trade program as an annual allocation of 
allowances as provided under 30 TAC Sec.  101.399.
    TCEQ submitted revisions to the DERC program on October 24, 2006 to 
address the 2006 condition. EPA is currently reviewing this SIP 
revision submittal and will take action at a later date and in a 
separate rulemaking on whether TCEQ's revisions to the DERC program 
adequately satisfied the terms of the 2006 DERC conditional approval. 
In the meantime, the DERC program can continue to be used in Texas, 
including the DFW area. Conditions 1 and 2 pertain to DERCs generated 
through permanent shutdowns and provide that any shutdown DERCs 
generated prior to September 30, 2002, in the DFW area would be 
available for use until September 8, 2010. Projected uses of these pre-
September 30, 2002 shutdown DERCs were appropriately modeled and 
accounted for by TCEQ as part of the overall DERC usage projections in 
DFW. Emission reductions subject to condition 3 do not impact the DFW 
attainment demonstration since EPA has not been contacted about using 
discrete emission reductions in the DFW area that have been generated 
in another state, nation, nonattainment area, or surrounding attainment 
counties. Conditions 4 and 5 modify the DERC rule to align the DERC 
generation and use procedures with EPA's Economic Incentive Program 
Guidance. These conditions do not negatively impact the projected uses 
of DERCs that were accounted for in the DFW attainment demonstration. 
Condition 6 only applies to DERCs used in the Houston/Galveston/
Brazoria ozone nonattainment area and is therefore not applicable to 
the DFW attainment demonstration.
    As discussed previously, TCEQ submitted revisions to the DERC 
program on October 24, 2006 to meet the 2006 DERC condition. EPA is 
currently reviewing these revisions to the Texas SIP and will take 
action in a separate rulemaking. These revisions, as noted above, have 
no impact upon the DFW area's attainment demonstration SIP and its 
reliance upon DERCs.
    Comment: Commenters believe that the DERC usage limitation should 
be required every year rather than allowing a different approach after 
2009. Commenters also believe that the enforceable flow control 
mechanism lacks specificity, may be backsliding (contrary to the Act's 
requirements) and may not demonstrate continued attainment of the 1997 
ozone standard in the DFW area.
    Response: Commenters will be able to address the substance of the 
DERC flow control SIP revision and its effect on the attainment 
demonstration once it is submitted to EPA. Until the State adopts and 
submits this revision to the DERC rule, it is premature to speculate 
about what the State might choose to do. However, we note that so long 
as the State demonstrates that the adopted rule will not interfere with 
attainment by June 2010 and maintenance of the NAAQS in the following 
years, EPA cannot mandate that the State apply the same approach in 
subsequent years that it chooses to apply in 2009.
    In our proposed conditional approval of the DFW attainment 
demonstration, we described the requirements of the 2009 DERC flow 
control condition and the enforceable mechanism that must relate it to 
the DFW attainment demonstration. We specifically recognized that the 
DERC usage limitation did not need to be required every year after 
2009. For all years after 2009, the TCEQ will have the option to retain 
the 3.2 tpd DERCs usage restriction or choose to increase the amount of 
tpd of DERCs usage, as long as there is an enforceable and replicable 
mechanism in place to ensure the increase in tpd of DERCs usage as 
offset by other measures, continues to ensure attainment in the area by 
having the same impact as if the 3.2 tpd DERCs usage restriction 
remained in effect. This includes the quantity and spatial allocation 
impacts of increased tpd of DERCs usage on the ozone levels. Therefore 
there would be no backsliding, even if the amount of tpd of DERC usage 
increased.
    In our proposal, we described a specific enforceable mechanism that 
would be acceptable concerning the substitution of other measures 
beginning January 1, 2010, allowing more than 3.2 tpd of DERCs usage in 
a year. As discussed in our DERC response to comments number 1, the 
public will receive three opportunities to review and comment on the 
merits and nature of the 2009 DERCs limit and the after-2009 
enforceable mechanism in the DFW area--during (1) the comment period 
for EPA's proposed conditional approval of the DFW attainment 
demonstration, (2) the comment period for the State's proposed 
rulemaking, and (3) the comment period for EPA's proposed action on 
whether the condition has been met.
    EPA believes that with the public review and comment opportunities 
provided, as well as the specifications outlined in our proposed 
conditional approval rulemaking, there will be sufficient opportunities 
to ensure that EPA has received relevant comments and information to 
allow EPA to make an informed decision on the acceptability and 
enforceability of the TCEQ's DERCs SIP revision submittal.
    Comment: Commenter states that the DERC emission reductions relied 
on in the DFW attainment demonstration are inadequate.
    Response: While EPA appreciates the effort and time of the 
commenter, the commenter has not provided any substantive description 
of why the DERC emission reductions relied on are inadequate for 
attainment.

F. Comments on Reasonably Available Control Measures (RACM)

    Comment: Numerous commenters note that the cement plants in the DFW 
area are the largest source of industrial NOX emissions in 
the DFW area. They claim there is available technology that would 
reduce NOX emissions by 90% and the companies should be 
required to install Selective Catalytic Reduction (SCR) as 
NOX RACM. They also note that the cement kilns are a large 
source of VOC emissions in the area but only one of ten kilns in 
Midlothian uses modern controls to reduce VOC emissions by 90%. 
Further, they claim that all Midlothian kilns should be required to 
install this technology, i.e., Regenerative Thermal Oxidizers (RTOs), 
as VOC RACM. Moreover, EPA needs to conduct an independent RACM 
analysis.
    Response: EPA interprets the Act's RACM requirement to mean that a 
measure is not RACM if it would not advance the attainment date (57 FR 
13498, 13560).\12\ This interpretation has been upheld. See Sierra Club 
v. EPA, 294 F.3d 155 (DC Cir. 2002) and Sierra Club v. United States 
EPA, 314 F.3d 735 (5th Cir. 2002). A state must consider all 
potentially available measures to determine whether they are reasonably 
available for implementation in the area,

[[Page 1923]]

and whether they would advance the area's attainment date. The state 
may reject measures as not meeting RACM, however, if they would not 
advance the attainment date, would cause substantial widespread and 
long-term adverse impacts, or would be economically or technologically 
infeasible. Additionally, potential measures requiring intensive and 
costly implementation efforts are not RACM. Sierra Club v. EPA at 162-
163 (DC Cir. 2002); Sierra Club v. EPA, 314 F.3d 735 (5th Cir. 2002); 
BCCA Appeal Group v. EPA, 355 F.3d 817 (5th Cir. 2003). To demonstrate 
measures that advance attainment of the ozone standard, the emission 
reductions from the measures must occur no later than the start of the 
2008 ozone season--i.e., by March 1, 2008, in order to advance 
attainment. Because there are no measures that could have been adopted 
and implemented by a date that has now passed, we believe it is 
appropriate to conclude that additional measures are not RACM.
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    \12\ See also EPA's ``Guidance on the Reasonably Available 
Control Measures (RACM) Requirement and Attainment Demonstration 
Submissions for Ozone Nonattainment Areas,'' John S. Seitz, 
Director, Office of Air Quality Planning and Standards, November 30, 
1999.
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    EPA expects States to prepare a reasoned justification for 
rejection of any available control measure. The resulting available 
control measures should then be evaluated for reasonableness 
considering their technological and economical feasibility, and whether 
they will advance attainment. In the case of the DFW SIP, TCEQ 
performed an analysis to determine whether all RACM were included in 
the SIP.
    To evaluate RACM for VOC measures, the State looked to all 
available RACM analyses and guidance for all the types of source 
categories in the DFW area and their potential controls. The State's 
analysis included evaluation of the potential RACM RTO control 
technology for cement kilns in the DFW area as VOC RACM. The State's 
photochemical modeling, however, indicated that the implementation of 
RTO technology on cement kilns in the DFW area would not advance 
attainment. The State's analyses indicated that it would take extremely 
large reductions of VOC emissions, over 100 tpd, to reduce the ozone 
level at the Denton monitor \13\ in the DFW area by 1 ppb. Thus only 
measures that will provide approximately 100 tpd of VOC emissions 
reductions will timely advance attainment. We were unable to identify 
any potential RACM measures in the State's submittal that would provide 
100 tpd or more of VOC reductions; this review also examined the use of 
RTO in cement kilns.
---------------------------------------------------------------------------

    \13\ To determine whether a measure would be reasonable to 
require for implementation, we calculated the magnitude of emissions 
reductions that would advance the attainment date at the monitors 
with the highest future design values (DVs), which are the Denton 
and Frisco monitors. Of these two monitors, the Denton monitor has 
the higher DV (2005-2007) of 94 ppb, although it should be noted 
that the DV for the DFW area for 2005-2007 is 95 ppb. However, 
considering the Denton monitor, if implementation of a particular 
measure would result in a decrease of 1 ppb at the Denton monitor in 
2008, we would consider such a measure as having the potential to 
advance the attainment date in the DFW area.
---------------------------------------------------------------------------

    In addition to reviewing the State's submittal, EPA reviewed the 
State's 2005 and 2007 Emissions Inventories for Point Sources. This 
review showed that the cement kilns do not emit sufficient amounts of 
VOCs to achieve 100 tpd in emissions reductions. See the Supplemental 
TSD for more details. Consequently, EPA agrees with the State that 
there are no additional RACM for stationary source VOC emissions in the 
DFW area. Based upon this review, EPA concludes that the use of RTO on 
cement kilns would not advance timely attainment.
    While we agree that one of the sources in the cement kiln source 
category uses the RTO technology--TXI 5 (Kiln 5), we do not 
extrapolate from this that use of the RTO technology on the other 
cement kilns in the DFW area will advance attainment of the 1997 ozone 
standard. See our previous comments and the Supplemental TSD for 
additional information.
    To evaluate RACM for NOX measures, the TCEQ looked to 
all available RACM analyses and guidance for all the types of source 
categories in the DFW area and their potential controls. The State's 
analysis also included evaluation of Low Temperature Oxidation 
Technology (LoTOx), SCR and Selective Non-Catalytic Reduction (SNCR) as 
potential NOX RACM for cement kilns. The State's modeling 
analyses indicate that reducing on-road mobile and area/non-road 
sources of NOX is most effective in reducing ozone levels at 
the Denton and Frisco monitors. Our evaluation of the State's analyses 
found that reductions of NOX emissions of at least 40 tpd 
would have the potential to advance the attainment date. See pages 2-29 
to 2-30 of the TCEQ SIP Narrative. Thus, only measures that will 
provide approximately 40 tpd of NOX emissions reductions 
will timely advance attainment. Neither the State nor EPA was able to 
identify any potential RACM measures that would provide 40 tpd or more 
in NOX emissions reductions. TCEQ had additional sensitivity 
modeling performed for cement kilns, which showed that the most 
stringent controls on the kilns would not advance the attainment date. 
See the Supplemental TSD for more detail.
    The Fifth Circuit in Sierra Club v. EPA, 314 F.3d 735, 745 (5th 
Cir. 2002) impressed upon EPA the duty to (1) demonstrate that it has 
examined relevant data, and (2) provide a satisfactory explanation for 
its rejection of a proposed RACM and why the proposed RACM, 
individually and in combination, would not advance the area's 
attainment date. See Ober, 243 F.3d at 1195 (quoting American Lung 
Ass'n v. EPA, 134 F.3d 388, 392-93 (DC Cir. 1998)). We reviewed the 
State's analysis and discussed our evaluation of it in the July 2008 
TSD and the December 2008 Supplemental TSD for this rulemaking; both 
TSDs are in the docket for this rulemaking. EPA evaluated the State's 
analysis and explained in the TSDs why we agree with the State that no 
additional measures are RACM for the DFW area and therefore the RACM 
requirement of the Act is met. We performed an independent analysis by 
reviewing all available data to determine whether RTO and 
NOX controls achieving 80-90% reduction are RACM for cement 
kilns in the DFW area; we agree with the State that additional control 
measures would not advance the attainment date.

G. Comments on the Failure-To-Attain Contingency Measures Plan

    Comment: Some commenters merely state that the contingency measures 
are insufficient without providing any support. Others comment that the 
four failure-to-attain contingency measures are insufficient because 
they will not result in demonstrative, verifiable, and enforceable 
emission reductions.
    Response: Some of the comments simply allege that the contingency 
measures are insufficient and the commenters provide no support, 
rationale or data for their claim. EPA explained why we believe the 
contingency measures are sufficient in the proposed rule and the 
commenters have not substantively questioned EPA's rationale. 
Therefore, no further response is necessary.
    Other commenters claim that the contingency measures will not 
result in demonstrative, verifiable and enforceable emission 
reductions. EPA interpreted sections 172 and 182 of the Act in the 
General Preamble (57 FR 13498, 13510) 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. The state must specify the

[[Page 1924]]

type of contingency measures and the quantity of emissions reductions.
    Quantifiable contingency measures are ones that are demonstrative 
and verifiable. An EPA-approved methodology can be used to calculate 
projected emissions reductions. The three VOC control measures in the 
contingency plan (Offset Lithographic Printing; Degassing or Cleaning 
of Stationary, Marine, and Transport Vessels; and Petroleum Dry 
Cleaning) rely upon long-established methodologies for calculation of 
their projected emissions reductions. See EPA's ``Introduction to Area 
Source Emission Inventory Development'' (Emission Inventory Improvement 
Program (EIIP), Volume III, January 2001). The EIIP was developed to 
estimate the effect of controls and acknowledges that regulatory 
programs are less than 100 percent effective for most source categories 
in most areas of the country. Specifically, Chapter 4 of the EIIP 
document describes the methodology for calculating an emission estimate 
for an area source with regulations in place that affect any of the 
individual sources within the source category using three factors: 
control efficiency, rule effectiveness, and rule penetration. These 
factors are used to develop more accurate emissions estimates and are 
defined as follows:
    (a) Control efficiency (CE) is the emission reduction efficiency, 
and is a percentage value representing the amount of a source 
category's emissions that are controlled. These numbers are often 
obtained from EPA's Control Technique Guidance documents.
    (b) Rule effectiveness (RE) is an adjustment to account for 
failures and uncertainties that affect the actual performance of the 
control. A default value of 0.80 is recommended unless better 
information is available for a particular source category.
    (c) Rule penetration (RP) is the percentage of the area source 
category that is covered by the applicable regulation or is expected to 
be complying with the regulation. The RP is calculated by taking the 
uncontrolled emissions covered by regulation and dividing by the total 
uncontrolled emissions. Default values are not feasible for RP because 
it is highly category- and location-dependent.
    These three factors are multiplied together to estimate the 
Controlled Area source Emissions (CAE).\14\
---------------------------------------------------------------------------

    \14\ If an area source is controlled, emissions are calculated 
by the following equation: CAE = UAE [1 - (CE) (RP) (RE)], where UAE 
= Uncontrolled Area Emissions estimate, and each of the other terms 
is defined above.
---------------------------------------------------------------------------

    For the DFW contingency measures plan, Texas estimated emissions 
for each source category using EPA's EIIP methodology. For Offset 
Lithographic Printing, the contingency measures plan applies to those 
sources with emissions below 50 tpy; for Degassing or Cleaning of 
Stationary, Marine, and Transport Vessels, the plan covers sources 
which are currently exempt from the State's VOC rules for degassing, 
including tanks smaller than 1 million gallons; and for Petroleum Dry 
Cleaning, the plan applies to sources using less than 2,000 gallons of 
solvent per year. These three contingency measures address sources that 
have emissions lower than the exemptions in the State's existing VOC 
RACT rules approved today as meeting RACT for both the standards.
    The fourth measure relied on is fleet turnover. Fleet turnover 
occurs each year--the model year composition of the local motor vehicle 
fleet changes as new vehicles are purchased and enter the fleet and old 
vehicles are scrapped. This results in a decrease in fleet average 
NOX and VOC emissions each year as older model year 
vehicles, certified to less stringent emission standards, leave the 
fleet and are replaced by newer vehicles certified to more stringent 
standards. The emission impacts of fleet turnover are calculated using 
EPA's MOBILE6.2 emission factor model. MOBILE6.2 calculates emission 
factors based on the standards that were in effect in each of the model 
years in the fleet and the relative fraction of each model year 
expected in the fleet in a specific calendar year. The relative 
fraction of each model year in the fleet is based on the local age 
distribution of the vehicle fleet, which is a specific input in 
MOBILE6.2 supplied by the state or local agency running the model, 
which in this SIP revision is the NCTCOG.
    EPA requires that states use MOBILE6.2 to estimate motor vehicle 
emissions in a SIP or conformity determination. EPA also specifies in 
guidance what types of local inputs are appropriate for use in a SIP. 
For example, EPA does not allow a state or local agency to project that 
the motor vehicle fleet will be newer in the future than it currently 
is. In SIPs, EPA accepts projections of future emissions, including the 
benefits of fleet turnover, calculated using MOBILE6.2 using inputs 
that conform to our guidance. The NCTCOG used the State vehicle 
registration database from July 2005; this conforms to EPA's guidance, 
is the latest available information and provides a more accurate 
estimation of future emissions levels.
    The three VOC measures have been approved into the SIP and 
therefore are enforceable by the EPA, the State and the public. The 
fleet turnover measure is a Federal rule and as such is enforceable by 
the EPA, the State and the public. Today's action makes the fleet 
turnover measure's projected SIP credits enforceable by the EPA and the 
public. The measures are surplus because they are not substitutes for 
mandatory, required emissions reductions and they are not being counted 
in any other control strategy.\15\ Finally, the measures are considered 
permanent because they continue for as long as the period in which they 
are used in the failure-to-attain contingency measures plan.
---------------------------------------------------------------------------

    \15\ EPA approved these three Chapter 115 measures into the DFW 
1-hour ozone SIP as part of the failure-to-attain contingency 
measures plan. EPA never triggered them to be implemented upon a 
finding of failure to attain the 1-hour standard. They remain in the 
DFW SIP and now the State is relying upon them as part of the 8-hour 
ozone failure-to-attain contingency measures plan. They are not 
required to meet the VOC RACT requirement for either standard.
---------------------------------------------------------------------------

    Comment: A commenter states that EPA may not approve contingency 
measures into the SIP that are already scheduled for implementation and 
are mandatory federal measures. Moreover, the attainment demonstration 
SIP relies upon these projected emissions reductions from fleet 
turnover. The emissions factors models used for projecting the future 
year's controlled emissions inventory include the improved tailpipe 
emission. The emissions reductions will occur passively and are not 
available ``to be undertaken'' in the likely event of a failure to 
attain. Accepting these as contingency measures violates the letter of 
the Act and the intended function of contingency measures--to step in 
when the SIP's primary control strategy fails. Texas may not rely on 
tailpipe emissions reductions as a contingency measure.
    Response: EPA's position is that the Act allows mandatory federal 
measures that are already scheduled for implementation to be used as 
contingency measures, as long as their emission reductions are beyond 
those needed for attainment or to meet reasonable further progress. The 
following are some of EPA's actions on the 1-hour ozone SIPs, approving 
the use of mandatory federal measures as part of the contingency 
measures plan: 62 FR 15844, (April 3, 1997); 62 FR 66279, (December 18, 
1997); 66 FR 30811 (June 8, 2001); 66 FR 586 and 66 FR 634, (January 3, 
2001). In the preambles for the proposed and final Phase 2 Rule, we 
state that Federal

[[Page 1925]]

measures that result in additional emission reductions beyond those 
needed for attainment or ROP in an area could serve as contingency 
measures for a failure to attain or meet the ROP requirements. (See 
Phase 2 Rule, proposed in 68 FR 32802 at 32837 (June 2, 2003), and 
final in 70 FR 71612 at 71651 (November 29, 2005)). Therefore, the 
State's inclusion of the Federal Motor Vehicle Control programs (FMVCP) 
occurring after the 2009 ozone season, is acceptable.
    The Federal measure in the failure-to-attain contingency measures 
plan is the projected emissions reductions from the 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). Only the emissions 
reductions projected to occur after 2009 from the FMVCP are relied upon 
to meet the 3% of the emissions in the adjusted 1999 base year 
emissions inventory.
    The modeling relies upon emissions reductions from the FMVCP that 
will become effective during the modeling period from 1999 to 2009. EPA 
disagrees that the attainment demonstration SIP relies upon the 
projected emissions reductions from fleet turnover occurring after 
2009. Said another way, we disagree that the reductions from fleet 
turnover used as contingency measures were relied upon in the 
demonstration that the area would attain by 2009.

H. Comments on the Attainment Motor Vehicle Emission Budgets (MVEBs)

    Comment: Commenters state that the MVEBs are flawed and are flawed 
for multiple reasons. In addition, in the absence of a competent 
attainment demonstration, the MVEBs are not approvable or adequate.
    Response: EPA disagrees with the commenters that the MVEBs are 
flawed. The Commenters provided no data or rationale for their 
comments. This statement, without any further explanation does not give 
EPA any guidance on the alleged inadequacy nor how the commenter would 
have EPA improve upon it. EPA, however, refers the Commenters to our 
detailed response, below.
    As discussed elsewhere, we believe that the plan provides for 
attainment of the ozone standard. For further explanation of how the 
attainment demonstration SIP provides for attainment, please see our 
responses in Section V-D above. Furthermore, we believe the budgets in 
the plan are consistent with the attainment plan and therefore should 
be approved.
    Further, the budgets in the SIP were established consistent with 
the process in 40 CFR 93.118(e). Under 40 CFR 93.118, budgets cannot be 
used for conformity until EPA has either found the budgets ``adequate'' 
or approved the SIP in which they are contained. On June 28, 2007, the 
availability of the budgets was posted on EPA's Web site for public 
comment. The comment period closed on July 30, 2007, and we received no 
comments. On March 21, 2008, we published a Notice of Adequacy 
Determination for the attainment MVEBs (73 FR 15152) where we announced 
that we found the 2009 attainment MVEBs ``adequate.'' In that notice we 
stated that the attainment MVEBs must be used in future DFW 
transportation conformity determinations.

I. Voluntary Mobile Source Emission Reduction Programs (VMEP)

    Comment: Commenters state that the Transportation Emission 
Reduction Measure (TERM) projects are inadequate.
    Response: The comment letter provides no support, rationale or data 
for its claim that the TERM projects are inadequate. EPA explained its 
rationale for proposing approval of the VMEP program in the proposed 
rule and the commenter fails to identify any defect in EPA's analysis. 
Therefore, no further response is required.
    Comment: A commenter states that EPA proposes to accept a series of 
capacity-increasing traffic projects as substitute control measures in 
the event that the VMEP NOX emissions are not achieved. The 
commenter states that the proposed TERMs involve roadway and highway 
capacity expansion to allow higher vehicle speeds in congested areas. 
The commenter further states that higher vehicle speeds result in 
increased NOX emissions and are counter productive to the 
stated purpose of supplying emissions reductions when VMEP reductions 
fail, and EPA should reject the TERM control measures' inclusion into 
the SIP.
    Response: EPA finds that the State, through the North Central Texas 
Council of Governments (NCTCOG), has committed to and is responsible 
for emissions reductions measures that are permanent, quantifiable, 
surplus, adequately supported, consistent, enforceable and in 
accordance with the Act and EPA guidance. The state, through the 
NCTCOG, also commits to monitor, assess, report, and, in the event that 
the NOX reductions are not achieved, remedy any shortfall in 
emissions reductions.
    It should be noted that EPA is not approving any TERMs, which would 
serve as the remedy to a shortfall of the VMEP at this time. The types 
of TERMs the state may use in the case of a shortfall are traffic 
signal improvements, Intelligent Transportation Systems (ITS), and/or 
freeway and/or arterial bottleneck removal. Because the State did not 
specifically identify or commit to using these additional measures, we 
did not review them for approvability. In the event of a shortfall, EPA 
will review the additional measures provided by the State for inclusion 
into the SIP. If EPA finds, at that time, that the measures would cause 
an increase in NOX emissions, we would not find them 
suitable for use to make up for an emissions reduction shortfall.
    Finally, the State must account for any such shortfall either by 
modifying implementation of the existing program to address the 
shortfall, adopting new measures, or revising the VMEP's emissions 
credits to reflect actual emissions reductions achieved, provided 
overall SIP commitments are met.\16\ Additions to the VMEP and changes 
to the VMEP credit in an effort to remedy any shortfall would be made 
in the form of a SIP revision. If TCMs are used to remedy the 
shortfall, a SIP revision may not be necessary.\17\
---------------------------------------------------------------------------

    \16\ See Richard D. Wilson, Acting Assistant Administrator for 
Air and Radiation, dated October 24, 1997, entitled ``Guidance on 
Incorporating Voluntary Mobile Source Emission Reduction Programs in 
State Implementation Plans (SIPs).''
    \17\ The state may submit TCMs to EPA under CAA 176(c)(8). The 
provision states that TCMs that are specified in an approved 
implementation plan may be replaced in the plan with alternate TCMs 
if the substitute measures achieve equivalent or greater emissions 
reductions than the TCM to be replaced. The provision also allows 
new TCMs to be added to an approved SIP. In order to substitute TCMs 
the CAA requires that the substitute TCM provide equivalent 
emissions reductions as the TCM that is being replaced in the 
approved SIP. The CAA also requires that, if the time for 
implementing the substitute TCM has not passed, the substitute 
measures must be implemented in accordance with a schedule that is 
consistent with the schedule that provided for the control measures 
in the implementation plan. Substitute and additional TCMs must be 
accompanied by evidence of adequate personnel and funding and 
authority under state/local law to implement, monitor and enforce 
the control measure; the measures must be developed in a 
collaborative process that includes participation by representatives 
of all affected jurisdictions, state agency and state/local 
transportation agencies and consultation with the EPA; there must be 
reasonable public notice and opportunity to comment; and the 
metropolitan planning organization, State air pollution control 
agency and the EPA concur with the equivalency of the substitute 
TCMs and on the additional TCM. Concurrence by the above agencies is 
required by the CAA and once the substitute is adopted, the TCM 
becomes, by operation of law, a part of the SIP and federally 
enforceable. It should be noted that consultation with the EPA 
regional offices serves to fulfill the requirement for consultation 
with the EPA Administrator and concurrence on both TCM substitutions 
and additions has been delegated to the EPA Regional Administrators. 
(Delegation of Authority 7-158: Transportation Control Measure 
Substitutions and Additions).

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[[Page 1926]]

VI. Final Action

    EPA is conditionally approving the DFW 1997 8-hour ozone attainment 
demonstration SIP and its 2009 attainment MVEBs, RACM determination, 
and failure-to-attain contingency measures plan, submitted by the State 
of Texas on May 30, 2007 and November 7, 2008, as supplemented on April 
23, 2008. EPA is fully approving two local control measures relied upon 
in the attainment demonstration, the VMEP and TCMs. We are also fully 
approving the DFW area SIP as meeting the RACT requirement for VOCs for 
the 1-hour ozone standard and the 1997 8-hour ozone standard. These 
revisions meet the requirements of the Act and EPA's regulations, and 
are consistent with EPA's guidance and policy. We are taking this 
action pursuant to section 110 and part D of the Act and EPA's 
regulations.

VII. 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 approves 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.
    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this action and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2).
    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by March 16, 2009. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this action for the purposes of 
judicial review nor does it extend the time within which a petition for 
judicial review may be filed, and shall not postpone the effectiveness 
of such rule or action. This action may not be challenged later in 
proceedings to enforce its requirements. (See section 307(b)(2).)

List of Subjects 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: December 17, 2008.
Richard E. Greene,
Regional Administrator, Region 6.

0
40 CFR part 52 is amended as follows:

PART 52--[AMENDED]

0
1. The authority citation for part 52 continues to read as follows:

Subpart SS--Texas

0
2. In Section 52.2270, the second table in paragraph (e) entitled ``EPA 
Approved Nonregulatory Provisions and Quasi-Regulatory Measures in the 
Texas SIP'' is amended by adding four new entries at the end.
    The revisions and additions read as follows:

Sec.  52.2270  Identification of plan.

* * * * *
    (e) * * *
* * * * *

[[Page 1927]]

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

                                                  * * * * * * *
Dallas-Fort Worth 1997 8-hour     Collin, Dallas,     May 23, 2007,       January 14, 2009    Conditional
 ozone Attainment Demonstration    Denton, Ellis,      November 7, 2008.   [Insert FR page     Approval.
 SIP and its 2009 attainment       Johnson, Kaufman,                       number where
 MVEBs, RACM demonstration, and    Parker, Rockwall                        document begins].
 Failure-to-Attain Contingency     and Tarrant
 Measures Plan.                    Counties, TX.
Transportation Control Measures.  Collin, Dallas,     May 23, 2007......  January 14, 2009
                                   Denton, Ellis,                          [Insert FR page
                                   Johnson, Kaufman,                       number where
                                   Parker, Rockwall                        document begins].
                                   and Tarrant
                                   Counties, TX.
VMEP............................  Collin, Dallas,     May 23, 2007......  January 14, 2009
                                   Denton, Ellis,                          [Insert FR page
                                   Johnson, Kaufman,                       number where
                                   Parker, Rockwall                        document begins].
                                   and Tarrant
                                   Counties, TX.
VOC RACT finding for the 1-hour   Collin, Dallas,     May 23, 2007......  January 14, 2009
 ozone NAAQS and the 1997 8-hour   Denton, Ellis,                          [Insert FR page
 ozone NAAQS.                      Johnson, Kaufman,                       number where
                                   Parker, Rockwall                        document begins].
                                   and Tarrant
                                   Counties, TX.
----------------------------------------------------------------------------------------------------------------

 [FR Doc. E9-118 Filed 1-13-09; 8:45 am]

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