
[Federal Register Volume 81, Number 2 (Tuesday, January 5, 2016)]
[Rules and Regulations]
[Pages 295-352]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2015-31904]



[[Page 295]]

Vol. 81

Tuesday,

No. 2

January 5, 2016

Part II





Environmental Protection Agency





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40 CFR Part 52





Approval and Promulgation of Implementation Plans; Texas and Oklahoma; 
Regional Haze State Implementation Plans; Interstate Visibility 
Transport State Implementation Plan To Address Pollution Affecting 
Visibility and Regional Haze; Federal Implementation Plan for Regional 
Haze; Final Rule

  Federal Register / Vol. 81 , No. 2 / Tuesday, January 5, 2016 / Rules 
and Regulations  

[[Page 296]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2014-0754; FRL-9940-21-Region 6]


Approval and Promulgation of Implementation Plans; Texas and 
Oklahoma; Regional Haze State Implementation Plans; Interstate 
Visibility Transport State Implementation Plan to Address Pollution 
Affecting Visibility and Regional Haze; Federal Implementation Plan for 
Regional Haze

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is partially 
approving and partially disapproving a revision to the Texas State 
Implementation Plan (SIP) submitted on March 31, 2009, to address the 
regional haze requirements of the Clean Air Act (CAA). The EPA is 
partially approving this SIP revision as meeting certain requirements 
of the regional haze program, including the Best Available Retrofit 
Technology (BART) requirements for facilities other than Electric 
Generating Units (EGUs). The EPA is partially disapproving the Texas 
SIP revision for not adequately addressing other requirements of the 
regional haze program related to reasonable progress, the long-term 
strategy, and the calculation of natural visibility conditions. The EPA 
is promulgating a Federal Implementation Plan (FIP), which includes 
sulfur dioxide (SO2) emission limits for fifteen EGUs 
located at eight coal-fired power plants, to address these 
deficiencies.
    In a previous rulemaking, the EPA had issued a limited disapproval 
of the Texas regional haze SIP with regard to Texas' reliance on the 
Clean Air Interstate Rule (CAIR), without promulgating a FIP. The EPA 
is not taking final action to address this deficiency at this time. The 
EPA is also disapproving portions of several separate infrastructure 
SIP revisions submitted by Texas for the purpose of addressing the 
requirements of the CAA regarding interference with other states' 
programs for visibility protection (interstate visibility transport) 
triggered by the issuance of the 1997 fine particulate matter 
(PM2.5) National Ambient Air Quality Standards (NAAQS), the 
1997 ozone NAAQS, the 2006 PM2.5 NAAQS, the 2008 ozone 
NAAQS, the 2010 Nitrogen Dioxide (NO2) NAAQS, and the 2010 
SO2 NAAQS. The EPA is deferring action at this time on 
promulgating a FIP to address these deficiencies.
    Finally, the EPA is finalizing its proposed partial disapproval of 
a revision to the Oklahoma SIP submitted on February 19, 2010, to 
address the regional haze requirements of the CAA. Specifically, the 
EPA is disapproving portions of the Oklahoma SIP related to reasonable 
progress and the establishment of reasonable progress goals for the 
Class I area located within the state. The EPA is promulgating a FIP to 
address these deficiencies.
    The EPA takes seriously its disapproval of SIPs, or portions 
thereof, and stands ready to work with the States to develop SIPs that 
would replace the Federal plans the EPA is promulgating today.

DATES: This final rule is effective on February 4, 2016.

ADDRESSES: The EPA has established a docket for this action under 
Docket ID No. EPA-EPA-R06-OAR-2014-0754. All documents in the docket 
are listed on the http://www.regulations.gov Web site. Although listed 
in the index, some information is not publicly available, e.g., 
Confidential Business Information (CBI) or other information whose 
disclosure is restricted by statute therefore is not posted to 
regulations.gov. Certain other material, such as copyrighted material, 
is not placed on the Internet and will be publicly available only in 
hard copy. Publicly available docket materials are available either 
electronically through http://www.regulations.gov or in hard copy at 
EPA Region 6, 1445 Ross Avenue, Suite 700, Dallas, Texas 75202-2733.

FOR FURTHER INFORMATION CONTACT: Joe Kordzi at 214-665-7186; or 
Kordzi.joe@epa.gov.

SUPPLEMENTARY INFORMATION: Throughout this document wherever ``we,'' 
``us,'' or ``our'' is used, we mean the EPA. Also throughout this 
document, when we refer to the Oklahoma Department of Environmental 
Quality (ODEQ), or the Texas Commission on Environmental Quality 
(TCEQ), we mean Oklahoma and Texas, respectively.

Table of Contents

I. Introduction
    A. Our Proposed Action
    B. Summary of Our Final Decision
    1. Texas
    2. Oklahoma Reasonable Progress Goals
    3. Federal Implementation Plan
II. Summary and Analysis of Major Issues Raised by Commenters
    A. General Comments
    B. State and Federal Roles in the Regional Haze Program
    C. Our Clarified Interpretation of the Reasonable Progress and 
Long-Term Strategy Requirements
    D. Consideration of Visibility in the Reasonable Progress 
Analysis
    E. Consultation Between Oklahoma and Texas
    F. Source Category and Individual Source Modeling
    G. Constitutional Law
    H. Stay of Effective Date, Consolidated Appropriations Act, and 
Executive Orders 13405 and 13211
    I. Controls in Addition to CAIR/CSAPR, and CSAPR Better Than 
BART
    J. Installation of Controls Beyond the First Planning Period
    K. Cost
    L. Cost versus Visibility Benefit
    M. Natural Conditions
    N. Consistency With Our Other Regional Haze Actions
    O. Modeling
    P. Interstate Visibility Transport
    Q. Disapproval of the Oklahoma and Texas Reasonable Progress 
Goals
    R. International Emissions
    S. Grid Reliability
    T. Determination of Nationwide Scope and Effect
III. Final Action
    A. Texas Regional Haze
    B. Oklahoma Regional Haze
    C. Interstate Visibility Transport
    D. Federal Implementation Plan
IV. Incorporation by Reference
V. Statutory and Executive Order Reviews
VI. Judicial Review

I. Introduction

    The purpose of Federal and state regional haze plans is to achieve 
a national goal, declared by Congress, of restoring and protecting 
visibility at 156 Federal Class I areas across the United States, most 
of which are national parks and wilderness areas with scenic vistas 
enjoyed by the American public. The national goal, as described in CAA 
Section 169A, is ``the prevention of any future, and the remedying of 
any existing, impairment of visibility in mandatory Class I Federal 
areas which impairment results from man-made air pollution.'' States 
are required to submit SIPs that ensure reasonable progress toward the 
national goal of remedying anthropogenic visibility impairment in 
Federal Class I areas, such as Big Bend National Park in Texas and the 
Wichita Mountains National Wildlife Refuge in Oklahoma.
    In today's action, we are partially approving and partially 
disapproving portions of a SIP revision submitted by Texas to address 
the requirements of the regional haze program. Texas' regional haze SIP 
submittal included long-term strategies for making reasonable progress 
towards improving visibility at all Class I areas impacted by emissions 
from Texas sources and set reasonable progress goals for the two Class 
I areas

[[Page 297]]

located within the state, the Big Bend and the Guadalupe Mountains 
National Parks. Texas addressed a key element of the regional haze 
program, the BART requirements, in part through reliance on CAIR. 
Specifically, for its EGUs, Texas relied on CAIR, which was issued in 
2005, to meet the BART requirements for emissions of SO2 and 
oxides of nitrogen (NOX). For particulate matter (PM) from 
its EGUs and for other categories of sources subject to the BART 
requirements, Texas concluded that no other BART controls were 
appropriate. Texas also considered whether additional measures beyond 
BART would be appropriate to ensure reasonable progress at its Class I 
areas and in Class I areas in nearby states, but concluded that no 
additional measures were needed to ensure reasonable progress. In its 
SIP submittal, Texas anticipated emissions reductions from CAIR, 
Federal mobile source standards, and other anticipated air pollution 
control requirements would adequately ensure reasonable progress toward 
improving visibility by 2018, the end of the first planning period.
    We took partial action in 2012 on Texas' regional haze SIP 
submittal. In our 2012 action, we issued a limited disapproval of the 
SIP revision because of Texas' reliance on CAIR to satisfy 
SO2 and NOX BART and to meet the long-term 
strategy requirements for its EGUs.\1\ As explained in that action, our 
limited disapproval of Texas' regional haze SIP (and the SIPs of 
thirteen other states addressed in the 2012 action) was the result of a 
decision by the D.C. Circuit remanding CAIR to the EPA.\2\ We concluded 
that because CAIR had been remanded and would remain in place only 
temporarily, we could not fully approve regional haze SIP revisions 
that relied on temporary reductions from CAIR. By issuing a limited 
disapproval rather than a full disapproval, however, we allowed Texas 
and these states to rely on CAIR for so long as CAIR was in place.\3\ 
We addressed the resulting deficiencies in the regional haze SIPs of a 
number of the fourteen states through FIPs that relied on CAIR's 
successor, the Cross State Air Pollution Rule (CSAPR), to achieve 
improvements in visibility. However, we did not finalize a FIP for 
Texas in that action.\4\ As a result, the deficiencies in Texas' 
regional haze SIP associated with its reliance on CAIR have not been 
addressed.
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    \1\ 77 FR 33642 (June 7, 2012).
    \2\ See North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008) 
(modified by 550 F.3d 1176).
    \3\ 77 FR at 33647.
    \4\ 77 FR at 33654 (explaining that the EPA was not finalizing a 
FIP for Texas in order to allow more time for the EPA to assess the 
SIP submittal from Texas addressing regional haze and noting that 
extra time was needed given ``the variety and number of BART 
eligible sources and the complexity of the SIP'').
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    We are also disapproving several SIP revisions submitted by Texas 
to address the requirements of CAA Section 110(a)(2)(D)(i)(II) with 
respect to visibility. This provision of the CAA requires that each 
state's SIP have adequate provisions to prohibit in-state emissions 
from interfering with measures required to protect visibility in any 
other state. To address this requirement, the SIP must address the 
potential for interference with visibility protection caused by the 
pollutant (including precursors) to which the new or revised NAAQS 
applies. In its SIP submittals addressing these requirements, Texas 
indicated that its regional haze SIP fulfilled its obligation for 
addressing emissions that would interfere with measures required to be 
included in the SIP for any other state to protect visibility.
    Finally, we are taking action on an element of the Oklahoma 
regional haze SIP submitted in February 2010. We previously issued a 
partial approval, and partial disapproval of the Oklahoma SIP in 2011, 
and promulgated a FIP to address the deficiencies that we had 
identified in our partial disapproval.\5\ Our FIP required the 
installation of scrubber retrofits at six units, located at three 
facilities in Oklahoma in order to meet BART requirements.\6\ Due to 
the special interrelationship of the visibility impairing transport of 
pollution between Texas and Oklahoma, we delayed action on the 
reasonable progress goals for the Wichita Mountains until we could 
review and evaluate Texas' SIP submittal. In today's action, we address 
the reasonable progress goals established by Oklahoma for this Class I 
area.
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    \5\ 76 FR 81728.
    \6\ 76 FR 81728.
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A. Our Proposed Action

    When we reviewed the Oklahoma regional haze SIP, we noted that 
sources in Texas had significant impacts on visibility in the Wichita 
Mountains. Given the magnitude of these interstate impacts, we 
determined that the Oklahoma and Texas regional haze SIPs were 
interconnected, especially considering the relationship between upwind 
and downwind states in the reasonable progress and long-term strategy 
provisions of the Regional Haze Rule. Although we were able to act on 
the majority of Oklahoma's SIP at that time, we deferred action on 
Oklahoma's reasonable progress goals for the Wichita Mountains until we 
could first assess whether Texas had reasonably considered the 
potential for controls on those of its sources that were impacting 
visibility at the Wichita Mountains.\7\ Having now reviewed the Texas 
regional haze SIP, it is clear that both Texas and Oklahoma 
acknowledged in their SIP submittals that sources in Texas have a large 
impact on visibility at the Wichita Mountains; indeed, the visibility 
impacts at this Class I area from Texas point sources are several times 
greater than the impacts from Oklahoma's own point sources.
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    \7\ 76 FR 16177 (``[W]e believe that to properly assess whether 
Oklahoma has satisfied the reasonable progress requirements of 
Section 51.308(d)(1), we must review and evaluate Texas' submittal. 
We will do this in the course of processing the Texas [regional 
haze] SIP.'')
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    During the interstate consultation required by the Regional Haze 
Rule, Oklahoma and Texas discussed the significant contribution of 
sources in Texas to visibility impairment at the Wichita Mountains, but 
Texas concluded that no additional controls were warranted for its 
sources during the first planning period to ensure reasonable progress 
at the Wichita Mountains, or at its own Class I areas, the Big Bend and 
the Guadalupe Mountains National Parks. In reaching this conclusion, 
Texas relied on an analysis that obscured the benefits of potentially 
cost-effective controls on those sources or groups of sources with the 
largest visibility impacts in these Class I areas by inclusion of those 
controls with little visibility benefit, but which served to increase 
the total cost figures. This flawed analysis deprived Oklahoma of the 
information it needed to properly assess the reasonableness of controls 
on Texas sources during the consultation process and prevented Texas 
from properly assessing the reasonableness of controls to remedy 
visibility at Big Bend and the Guadalupe Mountains. As a result, 
Oklahoma established reasonable progress goals for the Wichita 
Mountains that did not reflect any emission reductions from Texas 
beyond those that will be achieved by compliance with other 
requirements of the CAA. Texas established reasonable progress goals 
for its own Class I areas based on a similar assessment.
    Our proposed action on the Texas regional haze and interstate 
visibility transport SIP submittals and the Oklahoma regional haze SIP 
is discussed in detail in our notice of proposed rulemaking promulgated 
on

[[Page 298]]

December 16, 2014.\8\ In brief, we proposed to partially approve 
portions of the Texas regional haze SIP, including the determination by 
Texas that none of its non-EGU BART-eligible sources are subject to 
BART. We proposed to find, however, that Texas did not satisfy a number 
of requirements related to establishment of its reasonable progress 
goals and long-term strategy. We therefore proposed to disapprove 
Texas' reasonable progress goals. We proposed to disapprove Texas' 
calculation of natural visibility conditions and the uniform rates of 
progress for its two Class I areas. We proposed to disapprove the 
portions of SIP revisions separately submitted by Texas to meet the 
interstate visibility transport requirements for the 1997 
PM2.5 and ozone NAAQS, the 2006 PM2.5 NAAQS, the 
2008 ozone NAAQS, the 2010 NO2 NAAQS, and the 2010 
SO2 NAAQS. These submittals relied on the Texas regional 
haze SIP which, in turn, relied on CAIR to achieve the necessary 
emissions reductions. We proposed to find that as CAIR had been 
replaced by CSAPR, and CSAPR was scheduled to go into effect in 2015, 
Texas could not rely on its regional haze SIP to ensure that emissions 
from Texas do not interfere with the measures to protect visibility in 
nearby states. In addition, we proposed disapproval of these SIP 
submittals based on our proposed conclusion that additional control of 
SO2 emissions in Texas is needed to prevent interference 
with measures required to be included in the Oklahoma SIP to protect 
visibility.
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    \8\ 79 FR 74818.
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    Finally, we also proposed to disapprove Oklahoma's reasonable 
progress goals for the Wichita Mountains because Oklahoma did not 
satisfy several of the requirements related to setting those goals. In 
assessing the measures necessary to achieve the uniform rate of 
progress, Oklahoma demonstrated that eliminating all emissions from 
Oklahoma sources would not be sufficient to meet the uniform rate of 
progress in 2018. Oklahoma realized that the efforts to meet natural 
visibility conditions would require emission reductions from other 
states. The work done by the Central Regional Air Planning Association 
(CENRAP) showed that SO2 point sources in Texas were a 
significant contributor to haze at the Wichita Mountains. However, 
Oklahoma did not pursue this information in its consultations with 
Texas. As explained more fully in our proposed rule, we believe that 
the lack of development of critical information regarding reasonable 
reductions from Texas sources prevented Oklahoma from having adequate 
information to establish its reasonable progress goals for the Wichita 
Mountains. Oklahoma should have requested that Texas further 
investigate its sources, or requested additional reductions from Texas 
sources to ensure that all reasonable measures to improve visibility 
were included in Texas' long-term strategy and incorporated into the 
reasonable progress goals for the Wichita Mountains. We proposed to 
find that due to these flawed consultations, Oklahoma did not consider 
the emission reduction measures necessary to achieve the uniform rate 
of progress for the Wichita Mountains and did not adequately 
demonstrate that its reasonable progress goals were reasonable.
    We proposed FIPs for Texas and Oklahoma to remedy these 
deficiencies. Our proposed Texas FIP included SO2 emission 
limits on fifteen EGUs located at eight Texas facilities in order to 
make reasonable progress at the three Class I areas in Texas and 
Oklahoma. We estimate that our FIP will reduce the emissions of 
SO2 from Texas sources by approximately 230,000 tons per 
year. We proposed that compliance with these emission limits be based 
on 30-Boiler-Operating-Day (BOD) averages.\9\ The SO2 
emission limits were based on seven scrubber retrofits, seven scrubber 
upgrades, and the continued operation of an existing upgraded scrubber 
at the San Miguel power plant. We proposed that compliance with these 
limits be achieved within five years of the effective date of our final 
rule for the control assessments based on scrubber retrofits, and 
within three years of the effective date of our final rule for the 
control assessments based on scrubber upgrades. We proposed that 
compliance be achieved within one year for San Miguel.
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    \9\ We explained in our proposed rule that the BART Guidelines 
describe a boiler-operating-day ``to be any 24-hour period between 
12:00 midnight and the following midnight during which any fuel is 
combusted at any time at the steam generating unit.'' See 70 FR 
39172 (July 6, 2005). To calculate a 30 day rolling average based on 
the boiler-operating-day, the average of the last 30 ``boiler-
operating-days'' is used.
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    We proposed new reasonable progress goals for 2018 for Big Bend and 
the Guadalupe Mountains in Texas and for the Wichita Mountains in 
Oklahoma that take into account the additional emission reductions 
required in our proposed FIP for Texas. We proposed new estimates of 
natural conditions for the two Class I areas in Texas and proposed new 
uniform rates of progress for these areas. We proposed to rely on CSAPR 
to satisfy the SO2 and NOX BART requirements for 
EGUs in Texas. Finally, we proposed to rely on CSAPR and the 
SO2 emission limits in our proposed FIP to address the 
deficiencies identified in Texas' infrastructure SIP revisions. Our 
proposed FIP for Oklahoma did not include any additional requirements 
on emission sources within Oklahoma.
    Our electronic docket at www.regulations.gov contains Technical 
Support Documents (TSDs) and other materials that supported our 
proposal. Some information is protected as CBI and thus is not 
available to the public or posted electronically. Due to several 
requests from the public and due to the complex nature of our proposal, 
we provided for an extended public comment period, which closed on 
April 20, 2015.

B. Summary of Our Final Decision

    Below we present a summary of the major points of our final 
decision regarding the Texas regional haze SIP, the portions of Texas 
SIP submittals addressing interstate visibility transport, and those 
parts of the Oklahoma regional haze SIP that we have not previously 
acted upon. We summarize which parts of the Texas and Oklahoma regional 
haze SIPs and the interstate visibility transport portions of Texas' 
SIP submittals we are disapproving, which parts are cured by our FIP, 
and which parts we are deferring action upon.
1. Texas
    In this action, we are partially approving and partially 
disapproving portions of the SIP revision submitted by Texas to address 
the requirements of the regional haze program. We are also disapproving 
portions of several SIP revisions addressing the requirements of the 
CAA that prohibit air pollutant emissions from interfering with 
measures required to protect visibility in any other state, as 
described below.
a. Reasonable Progress Goals
    We are finalizing our disapproval of Texas' reasonable progress 
goals for Big Bend and the Guadalupe Mountains. We have determined that 
Texas has not demonstrated that its reasonable progress goals provide 
for reasonable progress towards meeting the national visibility goal. 
Specifically, we find that Texas did not satisfy several of the 
requirements of the regional haze rule at 40 CFR 51.308(d)(1) 
(hereinafter referred to as Sec.  51.308(d)) with regard to setting 
reasonable progress goals, most notably the requirement to reasonably 
consider

[[Page 299]]

the four statutory reasonable progress factors under Sec.  51.308 
(d)(1)(i)(A) and the requirement to adequately justify reasonable 
progress goals that are less stringent than the uniform rate of 
progress under Sec.  51.308 (d)(1)(ii).
    At the outset and as we discussed in detail in our proposal, we 
find the set of potential controls identified by Texas and how it 
analyzed and weighed the four reasonable progress factors under Sec.  
51.308(d)(1)(i)(A) was inappropriate.\10\ We are finalizing our 
determination that Texas' analysis was deficient and not approvable 
because the large control set it selected was not appropriately 
refined, targeted, or focused on those sources having the most 
significant and potentially cost-effective visibility benefits. We 
conclude this control set included controls on sources that would 
increase total cost figures, but would achieve very little visibility 
benefit. As discussed in our proposal, because Texas only estimated the 
visibility benefit of all the controls together, it was not able to 
assess the potential benefit of controlling those sources with the 
greatest visibility impacts, and potentially cost-effective controls. 
Therefore, the effects of those controls with the greatest visibility 
benefits were obscured by the inclusion of those controls with little 
visibility benefit. This only served to increase the total cost figure, 
making Texas' potential control set seem less attractive.\11\ We 
therefore finalize our disapproval of the portions of the Texas 
regional haze SIP addressing the requirements of Sec.  51.308 
(d)(1)(i)(A), regarding Texas' reasonable progress four-factor 
analysis.\12\
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    \10\ 79 FR 74838.
    \11\ 79 FR 74838. Additionally, the analysis of potential 
controls in the Texas SIP did not include any consideration of the 
reasonableness of control upgrades or increased utilization of 
existing controls to reduce emissions at sources with large 
visibility impacts at nearby Class I areas. These controls were 
validated as especially cost-effective by the technical record for 
this FIP. At costs ranging from $368/ton to $910/ton, over 100,000 
tpy of SO2 emission reductions can be achieved from a 
small number of scrubber upgrades, resulting in very cost-effective 
visibility benefits at Texas Class I areas and Class I areas in 
other states.
    \12\ The ``four-factor analyses'' or the ``four factors'' refers 
to the requirement in Sec.  51.308(d)(1)(i)(A) that in establishing 
a reasonable progress goal a state must consider the costs of 
compliance, the time necessary for compliance, the energy and non-
air quality environmental impacts of compliance, and the remaining 
useful life of any potentially affected sources, and include a 
demonstration showing how these factors were taken into 
consideration in selecting the goal.
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    We are also finalizing our disapproval of Texas' assessment of the 
emission reduction measures needed to achieve the uniform rate of 
progress for the period covered by the SIP, under Sec.  
51.308(d)(1)(i)(B). Although Texas correctly followed the procedures 
for analyzing and determining the rate of progress needed to attain 
natural visibility conditions by the year 2064, we find that Texas 
calculated this rate of progress on the basis of, and compared baseline 
visibility conditions to, a flawed estimation of natural visibility 
conditions for Big Bend and the Guadalupe Mountains.\13\ As discussed 
in the section below, we are finalizing our disapproval of Texas' 
calculation of natural visibility conditions for Big Bend and the 
Guadalupe Mountains in this action.
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    \13\ 79 FR 74833.
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    We also find that Texas failed to adequately justify reasonable 
progress goals that are less stringent than the uniform rate of 
progress under Sec.  51.308(d)(1)(ii).\14\ Although we agree with Texas 
that a rate of improvement necessary to attain natural visibility 
conditions by 2064 is not reasonable, we do not find that the rate of 
improvement that Texas has selected is reasonable, because we have 
determined that Texas' four-factor analysis and the analysis of 
emission measures needed to meet the uniform rate of progress does not 
meet the requirements of the Regional Haze Rule. We therefore finalize 
our disapproval of the reasonable progress goals for Big Bend and the 
Guadalupe Mountains under Sec.  51.308(d)(1)(ii). In so doing, we rely 
on the specific directive in Sec.  51.308(d)(1)(iii) that in 
determining whether the State's goal for visibility improvement 
provides for reasonable progress towards natural visibility conditions, 
the Administrator will evaluate the demonstrations developed by the 
State pursuant to paragraphs (d)(1)(i) and (ii).
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    \14\ 79 FR 74843.
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    With regard to the requirement under Sec.  51.308(d)(1)(iv) to 
consult with other states which may reasonably be anticipated to cause 
or contribute to visibility impairment at its Class I areas, we find 
that Texas appropriately identified those states with the largest 
impacts on Texas Class I areas and invited them for consultation. Based 
on our review of the CENRAP's source apportionment modeling and given 
the small modeled contributions from individual nearby states, 
especially when only considering anthropogenic sources that can be 
easily controlled in comparison with the size of impacts from Texas 
sources and international sources, we find that it was reasonable for 
Texas to have focused the analysis of additional controls on sources 
within Texas. We agree with Texas' determination that it was not 
reasonable to request additional controls from other states at this 
time. Therefore, we are finalizing our determination that Texas has 
satisfied the requirement under Sec.  51.308(d)(1)(iv).
    Under Sec.  51.308(d)(1)(vi), Texas may not adopt a reasonable 
progress goal that represents less visibility improvement than is 
expected to result from implementation of other requirements of the CAA 
during the applicable planning period. As discussed in our proposal, we 
find that Texas' reasonable progress goals for 2018, based on the 
CENRAP model projections, represent at least as much visibility 
improvement as was expected to result from implementation of other 
requirements of the CAA (i.e., requirements other than regional haze) 
during the applicable planning period.\15\ In this action we are 
finalizing our approval of the portion of the Texas regional haze SIP 
addressing the requirement under Sec.  51.308(d)(1)(vi).
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    \15\ 79 FR 74833.
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b. Calculations of Baseline and Natural Visibility Conditions
    As required by Sec.  51.308(d)(2)(i) of the Regional Haze Rule, 
Texas calculated baseline/current conditions for its two Class I areas, 
Big Bend and the Guadalupe Mountains, on the most impaired and least 
impaired days. Texas calculated baseline visibility conditions for Big 
Bend and the Guadalupe Mountains using available monitoring data over 
the 2000-2004 period and the new IMPROVE equation, as discussed in our 
proposal.\16\ We are finalizing our approval that Texas has satisfied 
the baseline visibility requirements of Sec.  51.308(d)(2)(i).
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    \16\ 79 FR 74832.
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    Under Sec.  51.308(d)(2)(iii), Texas must determine natural 
visibility conditions for the most impaired and least impaired days for 
the Class I areas in the state. Our guidance \17\ provides default 
natural conditions for the 20% worst and 20% best days for each Class I 
area based on the original IMPROVE equation. As documented in our 
guidance, states are allowed to use a ``refined'' approach or 
alternative approaches to the guidance defaults to estimate the values 
that characterize the natural visibility conditions of their Class I 
areas.\18\ The default natural

[[Page 300]]

conditions in our 2003 guidance were updated by the Natural Haze Levels 
II Committee utilizing the new IMPROVE equation and included some 
refinements to the estimates for the PM components.\19\ These estimates 
are referred to as the ``NC II'' default natural visibility conditions. 
Texas chose to derive a ``refined'' estimate of natural visibility 
conditions rather than using the default NC II values. Texas started 
with this refined version of default natural visibility conditions, but 
further altered some of its parameters concerning the contributions of 
coarse mass and fine soil by assuming that 100% of the fine soil and 
coarse mass concentrations in the baseline period should be attributed 
to natural causes and that the corresponding estimates in the NC II 
values should be replaced. We are finalizing our determination that 
Texas has not adequately demonstrated that all coarse mass and fine 
soil measured in the baseline period can be attributed to 100% natural 
sources and we are therefore disapproving Texas' calculated natural 
visibility conditions under Sec.  51.308(d)(2)(iii). We are also 
finalizing our disapproval of the portion of the Texas SIP that 
addresses the requirement to calculate the number of deciviews by which 
baseline conditions exceed natural conditions for the best and worst 
visibility days at the Texas Class I areas, under Sec.  
51.308(d)(2)(iv)(A). Because the calculation relies on the 
determination of natural visibility conditions, which we are 
disapproving, we must also disapprove Texas' calculation of the level 
of visibility impairment above natural conditions.
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    \17\ Guidance for Estimating Natural Visibility Conditions Under 
the Regional Haze Rule, EPA-454/B-03-005, September 2003.
    \18\ States are ``free to develop alternative approaches that 
will provide natural visibility conditions estimates that are 
technically and scientifically supportable. Any refined approach 
should be based on accurate, complete, and unbiased information and 
should be developed using a high degree of scientific rigor.'' 
Guidance for Estimating Natural Visibility Conditions Under the 
Regional Haze Rule, EPA- 454/B-03-005, September 2003, p 1-11
    \19\ The second version of the natural haze level II estimates 
based on the work of the Natural Haze Levels II Committee is 
available at: http://vista.cira.colostate.edu/Docs/IMPROVE/Aerosol/NaturalConditions/NaturalConditionsII_Format2_v2.xls.
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c. Long-Term Strategy
    Section 51.308(d)(3)(i) requires that where Texas has emissions 
that are reasonably anticipated to contribute to visibility impairment 
in any mandatory Class I area located in another state, it must consult 
with that state in order to develop coordinated emission management 
strategies. Texas also must consult with any other state having 
emissions that are reasonably anticipated to contribute to visibility 
impairment in any mandatory Class I area within it (we have discussed 
this consultation requirement above). Texas and Oklahoma agreed that 
visibility impairment at the Wichita Mountains due to emissions from 
sources in Texas is significant and that the impacts from point sources 
in Texas are several times greater than the impact from Oklahoma point 
sources. Furthermore, the ODEQ asserted in its consultations with the 
TCEQ, and elsewhere in its regional haze SIP, that it would not be able 
to reach natural visibility by 2064 without additional reductions from 
Texas sources. Oklahoma and Texas discussed the significant 
contribution of sources in Texas to visibility impairment at the 
Wichita Mountains during the interstate consultation process required 
by the Regional Haze Rule. The results of the CENRAP analysis 
demonstrated that Texas point sources, and in particular EGUs in 
northeast Texas, have large visibility impacts at the Wichita Mountains 
and that cost-effective controls were potentially available for some of 
these sources. Ultimately, Texas unreasonably determined that no 
additional controls were warranted for its sources during the first 
planning period to help achieve reasonable progress at the Wichita 
Mountains. In analyzing whether additional controls should be required 
for some of its sources under the long-term strategy provisions of the 
Regional Haze Rule, Texas relied on the same flawed analysis discussed 
above that it relied on to evaluate additional controls under the 
reasonable progress provisions to address visibility impairment at 
Texas' own Class I areas. Texas' analytical approach obscured the 
contributions of individual sources that Texas' own analysis indicated 
could be cost-effectively controlled. This deprived Oklahoma of the 
information it needed to properly assess whether there were reasonable 
controls for Texas sources and to properly establish reasonable 
progress goals for the Wichita Mountains that included the resulting 
emission reductions. We are therefore finalizing our disapproval of the 
portion of the Texas regional haze SIP addressing the requirement in 
Sec.  51.308(d)(3)(i) to ``consult with the other State(s) in order to 
develop coordinated emission management strategies.''
    Section 51.308(d)(3)(ii) requires that if Texas emissions cause or 
contribute to impairment in another state's Class I area, it must 
demonstrate that it has included in its regional haze SIP all measures 
necessary to obtain its share of the emission reductions needed to meet 
the progress goal for that Class I area. Section 51.308(d)(3)(ii) also 
requires that since Texas participated in a regional planning process, 
it must ensure it has included all measures needed to achieve its 
apportionment of emission reduction obligations agreed upon through 
that process. As discussed in our proposal, we find that the technical 
analysis developed by CENRAP and supplemented by Texas did not provide 
the information needed to evaluate the reasonableness of controls on 
those sources with the greatest potential to impact visibility at the 
Wichita Mountains.\20\ Texas' ``share of the emission reductions needed 
to meet the progress goal'' for the Wichita Mountains was not properly 
established because of the inadequacies in its technical analyses, 
which compromised its consultations with Oklahoma. We are finalizing 
our determination that Texas did not develop an adequate technical 
basis to inform consultations with Oklahoma in order to develop 
coordinated management strategies and to identify reasonable reductions 
from its sources. As a result, we find that Texas did not incorporate 
those reasonable reductions into its long-term strategy. For these 
reasons we are finalizing our determination that Texas did not 
adequately meet the requirement in Sec.  51.308(d)(3)(ii).
---------------------------------------------------------------------------

    \20\ 79 FR 74857.
---------------------------------------------------------------------------

    Section 51.308(d)(3)(iv) requires that Texas identify all 
anthropogenic sources of visibility impairment considered by it in 
developing its long-term strategy. We proposed to find that Texas' 2002 
and 2018 emission inventories are acceptable and that it satisfies 
Sec.  51.308(d)(3)(iv) and today, we take final action to approve that 
finding. However, under Sec.  51.308(d)(3)(iii), Texas must document 
the technical basis, including modeling, monitoring, and emissions 
information, on which it is relying to determine its apportionment of 
emission reduction obligations necessary for achieving reasonable 
progress in each mandatory Class I area it affects. Texas addressed 
this requirement mainly by relying on technical analyses developed by 
CENRAP and approved by all state participants, but it also performed an 
additional analysis building upon the work of CENRAP in order to 
evaluate additional controls under the reasonable progress and long-
term strategy provisions of the Regional Haze Rule. As discussed in our 
proposal, we find that this additional analysis was inadequate because 
the large control set Texas selected was not appropriately refined, 
targeted, or focused on those sources having significant and 
potentially cost-effective visibility benefits and did not provide the 
information necessary to determine the reasonableness of controls at 
those

[[Page 301]]

sources in Texas that have the greatest visibility impacts at the 
Wichita Mountains.\21\ Therefore, we are finalizing our disapproval of 
the portion of the Texas regional haze SIP that addresses the 
requirement in Sec.  51.308(d)(3)(iii) to document the technical basis 
on which the state is relying to determine its apportionment of 
emission reduction obligations necessary for achieving reasonable 
progress at the Wichita Mountains.
---------------------------------------------------------------------------

    \21\ 79 FR 74833.
---------------------------------------------------------------------------

    In developing its long-term strategy, the state must consider a 
number of factors identified in Sec.  51.308(d)(3)(v)(A)-(G). In this 
action, for the reasons discussed in our proposal,\22\ we are approving 
several portions of the Texas regional haze SIP as adequately 
addressing the following provisions of Sec.  51.308(d)(3)(v): (A) 
Emission reductions due to ongoing air pollution control programs, 
including measures to address RAVI (Reasonably Attributable Visibility 
Impairment); (B) measures to mitigate the impacts of construction 
activities; (D) source retirement and replacement schedules; (E) smoke 
management techniques for agricultural and forestry management purposes 
including plans as currently exist within the state for these purposes; 
(F) enforceability of emissions limitations and control measures; and 
(G) the anticipated net effect on visibility due to projected changes 
in point, area, and mobile source emissions over the period addressed 
by the long-term strategy. However, we are disapproving the portion of 
the Texas regional haze SIP addressing paragraph (C) of Sec.  
51.308(d)(3)(v), the requirement to consider emissions limitations and 
schedules for compliance to achieve the reasonable progress goals. As 
discussed in depth elsewhere in this document and in our separate 
Response to Comment (RTC) document, we have determined that Texas' 
analysis is inadequate because it does not provide the information 
necessary to determine the reasonableness of controls at those sources 
in Texas that significantly impact visibility at the Wichita Mountains 
in Oklahoma, or the Texas Class I areas. Therefore, we find that Texas 
did not properly consider the emissions limitations and schedules for 
compliance necessary to achieve reasonable progress at its Class I 
areas or the Wichita Mountains Class I area in Oklahoma.
---------------------------------------------------------------------------

    \22\ 79 FR 74862.
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d. Monitoring Strategy and Other Requirements
    Section 51.308(d)(4) requires that the Texas regional haze SIP 
contain a monitoring strategy for measuring, characterizing, and 
reporting of regional haze visibility impairment that is representative 
of all mandatory Class I areas within the state. This monitoring 
strategy must be coordinated with the monitoring strategy required in 
40 CFR 51.305 for RAVI. Compliance with this requirement may be met 
through participation in the IMPROVE network. Since the monitors used 
for the Guadalupe Mountains and Big Bend are IMPROVE monitors, we have 
determined that Texas has satisfied this requirement.\23\ Section 
51.308(d)(4)(i) requires the establishment of any additional monitoring 
sites or equipment needed to assess whether reasonable progress goals 
to address regional haze for all mandatory Class I areas within the 
state are being achieved. We approve of Texas' determination under this 
section that the IMPROVE network monitors that are already in place are 
adequate to assess Texas' reasonable progress goals.
---------------------------------------------------------------------------

    \23\ 79 FR 74863.
---------------------------------------------------------------------------

    Section 51.308(d)(4)(ii) requires that Texas establish procedures 
by which monitoring data and other information are used in determining 
the contribution of emissions from within Texas to regional haze 
visibility impairment at mandatory Class I areas both within and 
outside the state. The monitors at Big Bend and the Guadalupe Mountains 
are operated through the IMPROVE monitoring program, which is national 
in scope, and other states have similar monitoring and data reporting 
procedures, ensuring a consistent and robust monitoring data collection 
system. Section 51.308(d)(4)(iv) requires that the SIP must provide for 
the reporting of all visibility monitoring data to the Administrator at 
least annually for each mandatory Class I area in the state. Section 
51.308(d)(4)(vi) also requires that Texas provide for other elements, 
including reporting, recordkeeping, and other measures, necessary to 
assess and report on visibility. We are finalizing our determination 
that Texas has met these requirements through participation in the 
IMPROVE program.
    Section 51.308(d)(4)(v) requires that Texas maintain a statewide 
inventory of emissions of pollutants that are reasonably anticipated to 
cause or contribute to visibility impairment in any mandatory Class I 
area. The inventory must include emissions for a baseline year, 
emissions for the most recent year for which data are available, and 
estimates of future projected emissions. Texas must also include a 
commitment to update the inventory periodically. As discussed in the 
proposal, Texas has provided in the SIP a baseline emission inventory, 
estimates of future emissions, and emissions for the most recent year 
for which data was available at the time the SIP was developed.\24\ We 
approve the portion of the Texas regional haze SIP that addresses this 
requirement.
---------------------------------------------------------------------------

    \24\ 79 FR 74863.
---------------------------------------------------------------------------

    We also approve Texas' coordination with the Federal Land Managers 
(FLMs) under 40 CFR 51.308(i). As detailed in our proposal, Texas has 
satisfied these requirements through communications with the FLMs, 
providing for review of the draft Texas regional haze SIP by the FLMs, 
and describing how all FLM comments were addressed in the SIP. Texas 
also provided procedures for continuing consultations.\25\
---------------------------------------------------------------------------

    \25\ 79 FR 74864.
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e. Best Available Retrofit Technology
    We approve Texas' BART determinations for non-EGUs under 40 CFR 
51.308(e). We are approving Texas' determination of which non-EGU 
sources in the state are BART-eligible and the determination that none 
of the state's BART-eligible non-EGU sources are subject to BART 
because they are not reasonably anticipated to cause or contribute to 
visibility impairment at any Class I areas. We reviewed the various 
modeling techniques utilized by the TCEQ in evaluating and screening 
out the BART-eligible non-EGU sources and we concur with the results of 
analysis.\26\ We are approving the provisions in Texas' BART rules at 
30 Tex. Admin. Code (TAC) 116.1500-116.1540, with the exception of 30 
TAC 116.1510(d), which contains regulatory language addressing EGUs' 
reliance on CAIR to meet the BART requirements.
---------------------------------------------------------------------------

    \26\ 79 FR 74844.
---------------------------------------------------------------------------

    However, we are not finalizing our proposed actions with regard to 
the state's BART-eligible EGU sources. As described above, we issued a 
limited disapproval of the Texas regional haze SIP in 2012 because of 
Texas' reliance on CAIR to meet certain requirements of the regional 
haze program. To address the deficiencies in Texas' plan arising from 
its reliance on CAIR to meet the SO2 and NOX BART 
requirements for its EGUs, we proposed to substitute reliance on CSAPR. 
We previously determined that CSAPR would provide for greater 
reasonable progress than BART and established regulations that

[[Page 302]]

allow certain states to rely on CSAPR to meet the SO2 and 
NOX BART requirements for EGUs.\27\ CSAPR has been subject 
to extensive litigation, however, and on July 28, 2015, the D.C. 
Circuit Court issued a decision upholding CSAPR but remanding without 
vacating the CSAPR emissions budgets for a number of states.\28\ 
Specifically, the court invalidated a number of the Phase 2 ozone-
season NOX budgets and found that the SO2 budgets 
for four states resulted in over-control for purposes of CAA section 
110(a)(2)(D)(i)(I)(i). Texas' ozone-season NOX budget and 
SO2 budget are both involved with this remand, and we are 
currently in the process of determining the appropriate response to the 
remand. Given the uncertainty arising from the remand of Texas' CSAPR 
budgets, we have concluded that it would not be appropriate to finalize 
our proposed determination to rely on CSAPR as an alternative to 
SO2 and NOX BART for EGUs in Texas at this time. 
We note that some of the sources for which we are finalizing 
SO2 controls in this action are also potentially subject to 
the BART requirements. Should we determine in the future that it is 
necessary to perform source-specific BART determinations for these 
sources instead of relying on CSAPR, we anticipate that the 
SO2 controls we are finalizing today, which are currently 
the most stringent available, will also be sufficient to satisfy the 
SO2 BART requirement.
---------------------------------------------------------------------------

    \27\ 77 FR 33642.
    \28\ EME Homer City Generation v. EPA, 79 F.3d 118 (D.C. Cir.).
---------------------------------------------------------------------------

    In addition, we note that we proposed to approve Texas' 
determination that for its EGUs no PM BART controls were appropriate, 
based on a screening analysis of the visibility impacts from just PM 
emissions and the premise in our proposal that EGU SO2 and 
NOX were covered separately by participation in CSAPR 
allowing consideration of PM emissions in isolation. Because of the 
CASPR remand and resulting uncertainty regarding SO2 and 
NOX BART for EGUs, we have also decided not to finalize our 
proposed approval of Texas' PM BART determination. We will address PM 
BART for EGUs in Texas in a future rulemaking as well.
f. Interstate Visibility Transport
    The EPA is also disapproving portions of several separate 
infrastructure SIP revisions submitted by Texas for the purpose of 
addressing the requirements of the CAA regarding interference with 
other states' programs for visibility protection (interstate visibility 
transport). Section 110(a) of the CAA directs states to submit a SIP 
that provides for the implementation, maintenance, and enforcement of 
each NAAQS, which is commonly referred to as an infrastructure SIP. 
Among other things, CAA 110(a)(2)(D)(i)(II) requires that SIPs contain 
adequate provisions to prohibit interference with measures required to 
protect visibility in other states. We have concluded that to meet the 
requirements of CAA section 110(a)(2)(D)(i)(II): (1) Texas may not rely 
on its regional haze SIP, which relied heavily upon CAIR, to ensure 
that emissions from Texas do not interfere with measures to protect 
visibility in nearby states and (2) additional control of 
SO2 emissions in Texas is needed to prevent interference 
with measures required to be included in the Oklahoma SIP to protect 
visibility. Because the Texas regional haze SIP does not ensure that 
Texas emissions would not interfere with measures required to be 
included in the SIP for any other state to protect visibility, as 
required by section 110(a)(2)(D)(i)(II) of the Act, we are taking final 
action to disapprove portions of the Texas SIP submittals that address 
CAA provisions for prohibiting air pollutant emissions from interfering 
with measures required to protect visibility in any other state for the 
1997 PM2.5, 2006 PM2.5, 1997 ozone, 2008 ozone, 
2010 NO2, and 2010 SO2 NAAQS. Specifically, we 
are disapproving portions of the following SIP submittals made by Texas 
for new or revised NAAQS:

 April 4, 2008: 1997 8-hour Ozone, 1997 PM2.5 (24-
hour and annual)
 May 1, 2008: 1997 8-hour Ozone, 1997 PM2.5 (24-hour 
and annual)
 November 23, 2009: 2006 24-hour PM2.5
 December 7, 2012: 2010 NO2
 December 13, 2012: 2008 8-hour Ozone
 May 6, 2013: 2010 1-hour SO2

    We proposed to rely on CSAPR and the emission reductions required 
by our FIP for Texas to address these deficiencies in Texas' SIP 
submittals, but we have determined that it is not appropriate to 
finalize this determination at this time. Again, given the uncertainty 
following the D.C. Circuit Court's partial remand of the CSAPR budgets, 
we do not consider it appropriate to rely on CSAPR at this time to 
address the deficiencies on the Texas SIP, included those associated 
with interstate visibility transport obligation with respect to 
visibility. Therefore, this action does not finalize the portion of our 
proposed FIP addressing Texas' visibility transport obligations, as 
that portion of the FIP would have partially relied on CSAPR. We will 
address the visibility transport requirements for Texas in a future 
rulemaking, once the issues surrounding the partial remand are 
resolved.
2. Oklahoma Reasonable Progress Goals
    We are taking final action to disapprove the reasonable progress 
goals established by Oklahoma, and we are approving one portion and 
disapproving the other portions of the Oklahoma regional haze SIP that 
address the requirements of Sec.  51.308(d)(1). We find that Oklahoma's 
flawed consultation with Texas denied it the knowledge it needed--the 
extent to which cost-effective controls were available for those 
sources or groups of sources in Texas with the greatest potential to 
impact visibility at the Wichita Mountains--in order to properly 
construct its reasonable progress goal for the Wichita Mountains. 
Oklahoma and Texas discussed the significant contribution of sources in 
Texas to visibility impairment at the Wichita Mountains during the 
interstate consultation process required by the Regional Haze Rule. The 
results of the CENRAP analysis demonstrated that Texas point sources, 
and in particular EGUs in northeast Texas, have significant visibility 
impacts on the Wichita Mountains and that cost-effective controls were 
potentially available for some of these sources. However, Oklahoma did 
not pursue the point in its consultations with Texas under Sec.  
51.308(d)(1)(iv). Oklahoma did not have adequate information to 
establish its reasonable progress goal for the Wichita Mountains, and 
should have requested that the TCEQ further investigate these sources 
or requested additional reductions from Texas sources to ensure that 
all reasonable measures to improve visibility were included in Texas' 
long term strategy and incorporated into Oklahoma's reasonable progress 
goals for the Wichita Mountains. Furthermore, because of the flawed 
consultations with Texas, Oklahoma did not consider the emission 
reduction measures necessary to achieve the uniform rate of progress 
for the Wichita Mountains and did not adequately demonstrate that the 
reasonable progress goals it established were reasonable based on the 
four statutory factors under Sec.  51.308(d)(1)(ii).\29\ We therefore 
take final action to disapprove the reasonable progress goals as 
established by Oklahoma, and the portion of the Oklahoma regional haze 
SIP that addresses the requirements of

[[Page 303]]

Sec.  51.308(d)(1)(i) through (v) with respect to Oklahoma's 
establishment of its reasonable progress goals for the Wichita 
Mountains.
---------------------------------------------------------------------------

    \29\ 79 FR 74871, 74872.
---------------------------------------------------------------------------

    Under Sec.  51.308(d)(1)(vi), Oklahoma may not adopt a reasonable 
progress goal that represents less visibility improvement than is 
expected to result from implementation of other requirements of the CAA 
during the applicable planning period. As discussed in our proposal, we 
find that Oklahoma's reasonable progress goals for 2018, based on the 
CENRAP model projections, represent at least as much visibility 
improvement as was expected to result from implementation of other 
requirements of the CAA (i.e., requirements other than regional haze) 
during the applicable planning period.\30\ In this action we are 
approving the portion of the Oklahoma regional haze SIP that addresses 
the requirement under Sec.  51.308(d)(1)(vi).
---------------------------------------------------------------------------

    \30\ 79 FR 74870.
---------------------------------------------------------------------------

3. Federal Implementation Plan
    As explained above, we have identified a number of deficiencies in 
the SIP revisions submitted by Texas and Oklahoma to address the CAA's 
regional haze requirements and are finalizing partial disapproval of 
those plans. Accordingly, in this action we are also finalizing a FIP 
to address the deficiencies identified by our partial Texas SIP 
disapproval, except for those identified in our prior disapproval of 
the provisions in the Texas SIP addressing the EGU BART requirements. 
In this rulemaking, we are also disapproving those portions of the 
Texas SIP addressing the interstate visibility transport provisions of 
section 110(a)(2)(D)(i)(II), and are also not finalizing a FIP to 
address these deficiencies.
a. Four-Factor Analysis
    During our review of the reasonable progress and long-term strategy 
provisions of the Texas regional haze SIP, we realized that a more in-
depth analysis of Texas sources was needed to determine whether 
additional measures should be required to ensure reasonable progress. 
Although our technical approach is more fully described in our proposal 
\31\ and in our TSDs,\32\ it can be summarized as follows:
---------------------------------------------------------------------------

    \31\ 79 FR 74873.
    \32\ See Cost TSD and FIP TSD for detailed discussion of our 
technical approach.
---------------------------------------------------------------------------

     We used an analysis known as Q/d (i.e., annual emissions 
divided by the distance between the source and Class I area) as an 
initial screening test on over 1,600 facilities in Texas to determine 
which of these sources have the greatest potential to impact visibility 
at Class I areas. We identified 38 facilities (many facilities had 
multiple units) that were potentially the largest contributors to 
visibility impairment at downwind Class I areas.
     We realized that, due to the particular challenges 
presented by the geographic distribution and number of sources in Texas 
and the ability of a full photochemical model to assess visibility 
impacts on the 20% worst days, CAMx photochemical modeling \33\ was 
better technically suited to our needs than the more widely used 
CALPUFF model.\34\ We therefore contracted to have CAMx source 
apportionment modeling performed to determine which, if any, of these 
facilities had significant impacts.
---------------------------------------------------------------------------

    \33\ CAMx is a photochemical grid model (Comprehensive Air 
Quality Model with Extensions). CAMx model code and user's guide can 
be found at http://www.camx.com/download/default.aspx. Model code 
used in our analysis is available with the modeling files.
    \34\ Note that our reference to CALPUFF encompasses the entire 
CALPUFF modeling system, which includes the CALMET, CALPUFF, and 
CALPOST models and other pre and post processors. The different 
versions of CALPUFF have corresponding versions of CALMET, CALPOST, 
etc. which may not be compatible with previous versions (e.g., the 
output from a newer version of CALMET may not be compatible with an 
older version of CALPUFF). The different versions of the CALPUFF 
modeling system are available from the model developer at http://www.src.com/verio/download/download.htm.
---------------------------------------------------------------------------

     The CAMx modeling revealed that a relative handful of the 
point sources in Texas (less than 1%) were responsible for a large 
percentage of the visibility impairment at impacted Class I areas.
     Based on our consideration of these modeled visibility 
impacts, we determined that nine facilities (with 21 units) merited 
further modeling to assess what the visibility benefits might be from 
requiring emission reductions at these units. We modeled high and low 
emissions scenarios that spanned the available control scenarios for 
each unit.
    After identifying the sources with the largest visibility impacts 
at the three Class I areas of interest, and modeling the estimated 
visibility benefits corresponding to a robust range of potential 
controls, we considered whether controls on these sources would be 
necessary to ensure reasonable progress. As required by the CAA and the 
Regional Haze Rule, we took into account the following factors: \35\ 
(1) Time necessary for compliance, (2) energy and non-air quality 
environmental impacts of compliance, (3) remaining useful life, and (4) 
the costs of compliance. This analysis is commonly referred to as a 
``four factor analysis.'' Our Reasonable Progress Guidance \36\ notes 
the similarity between some of the reasonable progress factors and the 
BART factors and suggests that the BART Guidelines be consulted 
regarding the consideration of costs, energy and non-air quality 
environmental impacts, and remaining useful life. We therefore relied 
upon our BART Guidelines for assistance in assessing the reasonable 
progress factors, as applicable.
---------------------------------------------------------------------------

    \35\ CAA Section 169A(g), Section 51.308(d)(1)(i)(A).
    \36\ Guidance for Setting Reasonable Progress Goals Under the 
Regional Haze Program, U.S. Environmental Protection Agency, Office 
of Air Quality Planning and Standards, Air Quality Policy Division, 
Geographic Strategies Group, Research Triangle Park, NC. See section 
5.0.
---------------------------------------------------------------------------

    We noted that, with one exception,\37\ the issues relating to three 
of these factors--compliance time, energy and non-air quality 
environmental impacts, and remaining useful life--were common to all of 
the units we analyzed. Specifically, with the exception of the two 
units at the Tolk facility, these three factors did not present any 
issues that would impact the selection of the controls we analyzed. As 
a result, we proceeded to analyze the remaining factor, the costs of 
compliance.
---------------------------------------------------------------------------

    \37\ Our initial analysis of the Tolk facility indicated a 
potential shortage of water, meriting a special consideration of the 
energy and non-air quality environmental impacts of compliance.
---------------------------------------------------------------------------

    A number of the sources with the largest visibility impacts had 
units with no current SO2 controls. For each of these units, 
we analyzed Dry Sorbent Injection (DSI) at both a 50% control level and 
at either a 80% or 90% control level (depending on the type of 
particulate controls employed at the unit), thus bracketing our 
analyses between moderate and maximum levels of control. We also 
analyzed Flue Gas Desulfurization (FGD or ``scrubbers'') at these 
units. For both Spray Dryer Absorption (SDA--a type of dry scrubber), 
and wet FGD scrubbers, we analyzed control levels slightly below the 
maximum level of control these technologies have been demonstrated as 
capable of achieving at other EGUs.\38\ We then adapted our Integrated 
Planning Model (IPM) \39\ cost algorithms that had been developed for 
DSI, SDA, and wet FGD and performed our cost analyses for potential 
controls on these units.
---------------------------------------------------------------------------

    \38\ We analyzed SDA at 95% control with a floor of 0.06 lbs/
MMBtu, and wet FGD at 98% control with a floor of 0.04 lbs/MMBtu.
    \39\ Documentation regarding our IPM Model can be found here: 
http://www2.epa.gov/airmarkets/power-sector-modeling.

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[[Page 304]]

    Some of the units we analyzed were already fitted with 
underperforming \40\ wet FGDs. For each of these units, we conducted 
control cost analyses for upgrading those scrubbers, using site-
specific information obtained from the facilities under the authority 
provided by CAA section 114. Because the information we obtained was 
claimed as CBI, and our subsequent analyses that relied on it are also 
protected, we cannot share them with the public. However, our analyses 
were available for review by the affected facilities. Similarly, our 
responses to comments that incorporate information subject to CBI 
claims are in a separate document available to the CBI claimants that 
is part of the administrative record of this action but is not 
available for public review.
---------------------------------------------------------------------------

    \40\ By ``underperforming,'' we mean scrubber systems that are 
meeting their permit limits, but are capable of achieving greater 
levels of control through increased utilization and optimization.
---------------------------------------------------------------------------

    We also considered projected visibility benefits in our analysis. 
As we previously stated in proposing to take action on an Arizona 
regional haze SIP: \41\
---------------------------------------------------------------------------

    \41\ See 79 FR 9353 n.137. We also used the same reasoning in 
our final action on the Arizona regional haze SIP. See 79 FR 52420.

While visibility is not an explicitly listed factor to consider when 
determining whether additional controls are reasonable, the purpose 
of the four-factor analysis is to determine what degree of progress 
toward natural visibility conditions is reasonable. Therefore, it is 
appropriate to consider the projected visibility benefit of the 
controls when determining if the controls are needed to make 
---------------------------------------------------------------------------
reasonable progress.

    Having identified the sources that have the greatest visibility 
impacts on the three Class I areas of interest, the visibility benefits 
that could be obtained by controlling those sources, and the costs of 
potential controls, we developed a strategy to determine which sources, 
if any, should be controlled under the reasonable progress and long-
term strategy provisions of the CAA and Regional Haze Rule. To make 
this determination, we took into account the cost-effectiveness ($/ton 
of emissions removed) of the potential controls along with their 
projected visibility benefits. The ample precedent of other SIPs and 
FIPs has established a range of cost-effectiveness values within which 
controls have generally been required to meet provisions of the 
Regional Haze Rule. All of the new DSI, SDA, and wet FGD controls and 
upgraded scrubber controls we costed easily fell within this range. In 
fact, the highest cost-effectiveness value for the controls we analyzed 
was $3,221/ton for the Tolk Unit 172B SDA, a value that is less than 
the cost threshold adopted by Texas, after adjusting for the escalation 
of costs over time.\42\ For sources other than Tolk, all of the 
controls we are requiring are more cost-effective than Texas' $2,700/
ton threshold, even without an adjustment.
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    \42\ Texas used a $2,700/ton cost-effectiveness threshold, 
without regard to visibility benefit. While we found flaws in the 
way Texas established and used this threshold, it is illustrative of 
the cost-effectiveness of the controls required in this rulemaking. 
Conservatively escalating the $2,700/ton value from when it was 
first developed for the CAIR rule, which was finalized on March 10, 
2005, to the time of our analysis, which was conducted in 2014, 
results in a value of $3,322/ton (i.e., the Chemical Engineering 
Plant Cost Index for 2005 = 468.2, and that for 2014 = 576.1; $2,700 
x 576.1/468.2 = $3,322).
---------------------------------------------------------------------------

    As explained above, due to the challenges presented by the 
geographic distribution and number of sources in Texas and the ability 
of a full photochemical model to assess visibility impacts on the 20% 
worst days, we determined that the CAMx photochemical model was best 
suited to our needs. While CALPUFF modeling was often used for 
assessing visibility benefits in other regional haze SIP actions, the 
large transport distances in Texas and our concerns about the technical 
capabilities of CALPUFF made the use of CALPUFF impractical.\43\ As we 
have discussed in our FIP TSD and our separate RTC document, the 
results of our CAMx modeling cannot be directly compared to the results 
of CALPUFF modeling, which was used in the vast majority of other BART 
determinations and some reasonable progress determinations, because of 
differences between the models, model inputs, and metrics used.\44\ 
Many of these differences result in CAMx modeled visibility impacts and 
benefits that are much lower than the CALPUFF modeled visibility 
impacts and benefits relied on in other actions. For a more thorough 
explanation of this complex issue, please refer to our FIP TSD and 
discussion in the RTC document. As a result, we were unable to rely on 
prior visibility analyses based on the use of CALPUFF in other actions 
as precedent for assessing the results of our CAMx visibility analysis 
in this action.\45\
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    \43\ The TCEQ conducted BART screening modeling with CAMx for 
the majority of the BART-eligible sources in Texas. The TCEQ 
requested to use CAMx instead of CALPUFF because of the advantages 
of CAMx to evaluate many sources individually in one or two modeling 
runs and the technical advantages of CAMx over CALPUFF when large 
distances are involved. As discussed in a response to comment in the 
modeling section of this document, we approved the TCEQ's approach 
of using CAMx for BART screening in 2007.
    \44\ See the Modeling section of the RTC document and our FIP 
TSD, beginning on page A-35, in which we explain why key differences 
in CALPUFF for BART and CAMx modeling for RP preclude the comparison 
of their respective results. Some of the major differences are: (1) 
CALPUFF uses maximum 24-hour emission rates, while CAMx uses annual 
average emission rates; (2) CALPUFF focuses on the day with the 98th 
percentile highest visibility impact from the source being 
evaluated, whereas CAMx focuses on the average visibility impacts 
across the 20% worst days regardless of whether the impacts from a 
specific facility are large or small; and (3) CAMx models all 
sources of emissions in the modeling domain, which includes all of 
the continental U.S., whereas CALPUFF only models the impact of 
emissions from one facility without explicit chemical interaction 
with other sources' emissions.
    \45\ Many commenters alleging inconsistency with our previous 
actions failed to appreciate this point and attempt to compare 
directly CALPUFF results to CAMx modeled results.
---------------------------------------------------------------------------

    To evaluate the projected visibility benefits of controls in our 
cost evaluation, we considered a number of metrics, such as change in 
deciviews under 2018 projected levels of air pollution at the three 
Class I areas and under estimated natural visibility conditions, change 
in light extinction, and change in the percentage of total light 
extinction.\46\ We also considered the visibility benefit of emission 
reductions from recent actual emission levels versus CENRAP 2018 
projected emission levels at these sources. As we discuss further in 
our FIP TSD and in responses in our RTC document, to provide context 
regarding the significance of individual source impacts, we compared 
the individual source impacts with CENRAP source apportionment modeling 
results for impacts from all emission sources within a state and 
impacts from all emission sources within a state within a specific 
source type. We also compared these individual source impacts to the 
impact levels used by the states for triggering consultation with 
another state about its overall impacts, and the estimated range of 
anticipated visibility benefits resulting from required controls in 
other actions.\47\ Ultimately, after considering all four factors, we 
identified a set of reasonable controls for the first planning period 
for those sources with the largest visibility impacts that would 
provide for meaningful visibility improvements towards the goal of 
natural visibility conditions.
---------------------------------------------------------------------------

    \46\ For a full discussion on our review of all the modeling 
results, and factors that we considered in evaluating and weighing 
all the results, precedents, and other policy concerns please see 
Appendix A of our FIP TSD.
    \47\ See our FIP TSD at A-75.
---------------------------------------------------------------------------

    After extending our public comment period from the original date of 
February 17, 2015, to an extended date of April 20, 2015, we considered 
and responded to thousands of comments both for and against our 
proposal, the

[[Page 305]]

most significant of which we summarize in section II below. While these 
comments resulted in some adjustments to our cost-effectiveness 
estimates for our proposed scrubber upgrades, ultimately these changes 
were not so significant as to change our proposed control decision. 
After careful consideration of all of the comments and the information 
provided, we find that the units and the control levels should be 
finalized as proposed.
b. Final SO2 Emission Limits
    As discussed further in our FIP TSD,\48\ our emission limits are 
based on the installation of scrubber retrofits, scrubber upgrades, and 
in the case of San Miguel, the continued operation of its already 
performed scrubber upgrade. Consistent with our proposal, the final FIP 
requires that the SO2 emission limits contained in Table 1 
below be met on a 30 BOD period basis.
---------------------------------------------------------------------------

    \48\ See our FIP TSD, Section 4.4 and 4.5. Our Cost TSD develops 
the bases for the costs and emission limits.

       Table 1--Final 30-Boiler-Operating-Day SO2 Emission Limits
------------------------------------------------------------------------
                                                             Final SO2
                          Unit                            emission limit
                                                            (lbs/MMBtu)
------------------------------------------------------------------------
Scrubber Upgrades:
  Sandow 4..............................................            0.20
  Martin Lake 1.........................................            0.12
  Martin Lake 2.........................................            0.12
  Martin Lake 3.........................................            0.11
  Monticello 3..........................................            0.06
  Limestone 2...........................................            0.08
  Limestone 1...........................................            0.08
  San Miguel *..........................................            0.60
Scrubber Retrofits:
  Big Brown 1...........................................            0.04
  Big Brown 2...........................................            0.04
  Monticello 1..........................................            0.04
  Monticello 2..........................................            0.04
  Coleto Creek 1........................................            0.04
  Tolk 172B.............................................            0.06
  Tolk 171B.............................................            0.06
------------------------------------------------------------------------
* As we noted in our proposal, we do not anticipate that San Miguel will
  have to install any additional control in order to comply with this
  emission limit.

    As we discuss in our proposal,\49\ we find that five years is an 
adequate amount of time to allow for the installation of scrubber 
retrofits, and three years is an adequate amount of time to allow for 
the installation of scrubber upgrades. We also find that one year is an 
adequate amount of time for compliance for San Miguel, for which we do 
not anticipate the need for the installation of any additional 
equipment. We are therefore finalizing our requirements as proposed 
providing that compliance with the limits in Table 1 be achieved 
within:
---------------------------------------------------------------------------

    \49\ 79 FR 74823.
---------------------------------------------------------------------------

     Five years of the effective date of our final rule for Big 
Brown Units 1 and 2, Monticello Units 1 and 2, Coleto Creek Unit 1, and 
Tolk Units 171B and 172B.
     Three years of the effective date of our final rule for 
Sandow 4; Martin Lake Units 1, 2, and 3; Monticello Unit 3; and 
Limestone Units 1 and 2.
     One year of the effective date of our final rule for San 
Miguel.
c. Treatment of Potential Error in Scrubber Upgrade Efficiency 
Calculations
    In the Cost TSD that accompanied our proposal, we discussed how we 
calculated the SO2 removal efficiency of the units we 
analyzed for scrubber upgrades.\50\ We noted that, due to a number of 
factors that we were unable to accurately quantify, our calculations of 
current removal efficiencies could contain some error. Based on the 
results of our scrubber upgrade cost analysis, however, we did not 
believe that any such errors, if present, would affect our proposed 
decision to require the scrubber upgrades because they were all cost-
effective (low $/ton of emissions removed). In other words, were we to 
make reasonable adjustments in the additional tons removed under the 
FIP limits to account for any potential error in our calculation of 
current scrubber removal efficiencies, we would still propose to 
upgrade these SO2 scrubbers. After considering comments and 
other information submitted by the facility owners in response to our 
proposal, and as discussed more fully in our responses to comments on 
cost in the RTC document and section III below, we continue to conclude 
that upgrading an underperforming SO2 scrubber is one of the 
most cost-effective pollution control measures a coal-fired power plant 
can implement to improve visibility at Class I areas.
---------------------------------------------------------------------------

    \50\ See Section 6 of our Cost TSD.
---------------------------------------------------------------------------

    We also proposed that the units required to conduct scrubber 
upgrades must meet SO2 emission limits based on 95% removal 
in all cases. This removal efficiency is below the upper end of what an 
upgraded wet SO2 scrubber can achieve, which is 98-99%, as 
we noted in our Cost TSD. We also noted that a 95% removal efficiency 
assumption provides an adequate margin of error, such that all of the 
units should be able to comfortably attain the emission limits we 
proposed. However, for the operator of any unit that disagreed with us 
on this point, our proposal included a pathway for such operators to 
seek and for us to consider revised emission limits in this final 
action by submitting specific comments on the issue and taking other 
specific steps.\51\ We did not receive any comments from an owner or 
operator that was interested in using this pathway to potentially 
obtain a modified SO2 emission limit. While we remain open 
to discussions concerning this procedure, we are finalizing the 
emission limits and compliance schedule for the affected units as 
proposed.
---------------------------------------------------------------------------

    \51\ 79 FR 74885.
---------------------------------------------------------------------------

    Similarly, to ensure that San Miguel can meet our final FIP 
emission limitation, we are finalizing the following compliance option 
for the owner and operator of San Miguel as an alternative to the final 
emission limit of 0.60 lbs/MMBtu based on a 30 day BOD average:
     Install a CEMS at the inlet of the scrubber system. The 30 
BOD SO2 average from the existing outlet CEMS must read at 
or below 6.0% (94% control) of a 30 BOD SO2 average from the 
inlet CEMS.

By no later than its compliance date, San Miguel must inform us in 
writing of its decision to select this option for compliance. The FIP 
provides automatically for this compliance option and therefore if San 
Miguel chooses it, no SIP revision submittal is required from Texas.
d. Natural Conditions for the Texas Class I Areas
    Consistent with our proposal and as discussed further in our FIP 
TSD,\52\ we are finalizing the natural conditions for the Guadalupe 
Mountains and Big Bend as follows:
---------------------------------------------------------------------------

    \52\ See discussion beginning on 79 FR 74885, and section 10 of 
our FIP TSD.

 Table 2--Natural Conditions (NC II) for the Guadalupe Mountains and Big
                                  Bend
------------------------------------------------------------------------
                                                  20% Best    20% Worst
                 Class 1 Area                    days (dv)    days (dv)
------------------------------------------------------------------------
Guadalupe Mountains...........................         0.99         6.65
Big Bend......................................         1.62         7.16
------------------------------------------------------------------------

    We recommend that the State of Texas re-evaluate the natural 
conditions for its Class I areas in its next regional haze SIP in 
consultation with us and the FLMs.

[[Page 306]]

e. Calculation of Visibility Impairment for the Texas Class I Areas
    Consistent with our proposal and as discussed further in our FIP 
TSD,\53\ our final recalculated natural visibility conditions, and our 
calculation of visibility impairment for the Guadalupe Mountains and 
Big Bend are found in the table below. We recalculated the number of 
deciviews by which baseline visibility conditions exceed natural 
visibility conditions for these Class I areas pursuant to Sec.  
51.308(d)(2)(iv)(A). Specifically, in our calculations, we replaced 
Texas' calculations of natural visibility conditions for its Class I 
areas with the adjusted default values (NC II), as discussed in our 
proposal. We then determined the amount the baseline visibility values 
exceeded the natural visibility conditions to calculate visibility 
impairment for each area. We are finalizing the following estimates of 
visibility impairment for the Guadalupe Mountains and Big Bend:
---------------------------------------------------------------------------

    \53\ See discussion beginning on 79 FR 74886, and section 11 of 
our FIP TSD.

                       Table 3--Revised Visibility Metrics for the Class I Areas in Texas
----------------------------------------------------------------------------------------------------------------
 
----------------------------------------------------------------------------------------------------------------
                         Class I Area                              Most Impaired (dv)      Least Impaired (dv)
                                                               -------------------------------------------------
                                                                    Baseline Visibility Conditions, 2000-2004
----------------------------------------------------------------------------------------------------------------
Big Bend......................................................                    17.30                     5.78
Guadalupe Mountains...........................................                    17.19                     5.95
                                                               -------------------------------------------------
                                                                          Natural Visibility Conditions
                                                               -------------------------------------------------
Big Bend......................................................                     7.16                     1.62
Guadalupe Mountains...........................................                     6.65                     0.99
                                                               -------------------------------------------------
                                                                   Extent Baseline Exceeds Natural Visibility
                                                                                   Conditions
                                                               -------------------------------------------------
Big Bend......................................................                    10.14                     4.16
Guadalupe Mountains...........................................                    10.54                     4.96
----------------------------------------------------------------------------------------------------------------

f. Consideration of the Uniform Rates of Progress
    Consistent with our proposal and as discussed further in our FIP 
TSD,\54\ we are finalizing the uniform rates of progress for the 20% 
worst days for the Guadalupe Mountains and Big Bend contained in Table 
4 below. Specifically, in our calculations, we replaced Texas' 
calculations of natural visibility conditions for its Class I areas 
with the adjusted default values (NC II), as discussed in our proposal, 
and we recalculated the uniform rates of progress as follows:
---------------------------------------------------------------------------

    \54\ See discussion beginning on 79 FR 74886, and section 12 of 
our FIP TSD.

                                 Table 4--Class I Area Uniform Rates of Progress
----------------------------------------------------------------------------------------------------------------
                                                      Annual
                                     Baseline       improvement    Visibility at    Improvement       Natural
          Class I Area              conditions    needed to meet       2018       needed by 2018  conditions  at
                                                        URP                                            2064
                                            (dv)            (dv)            (dv)            (dv)            (dv)
----------------------------------------------------------------------------------------------------------------
Big Bend........................           17.30            0.17           14.93            2.37            7.16
Guadalupe Mountains.............           17.19            0.18           14.73            2.46            6.65
----------------------------------------------------------------------------------------------------------------

g. Revised Reasonable Progress Goals for the Guadalupe Mountains and 
Big Bend
    We are finalizing our technical analysis that was lacking in Texas' 
development of its reasonable progress goals for the Guadalupe 
Mountains and Big Bend. As discussed in our proposal and FIP TSD,\55\ 
we are establishing new reasonable progress goals based on our 
technical analysis. The new reasonable progress goals are as follows:
---------------------------------------------------------------------------

    \55\ See discussion beginning on 79 FR 74886, and section 13 of 
our FIP TSD.

 Table 5--Reasonable Progress Goals for 2018 for the Guadalupe Mountains
                              and Big Bend
------------------------------------------------------------------------
                                                20% Best      20% Worst
                Class I area                   days  (dv)    days  (dv)
------------------------------------------------------------------------
Guadalupe Mountains.........................          5.70         16.26
Big Bend....................................          5.59         16.57
------------------------------------------------------------------------


[[Page 307]]

    Our new reasonable progress goals for 2018 reflect only the 
additional estimated visibility benefit from the required controls 
anticipated to be in place by 2018, which are the scrubber upgrades. 
While the required scrubber retrofits will provide for additional 
visibility improvement at the Class I areas \56\ that we consider 
necessary for reasonable progress towards natural visibility 
conditions, we do not anticipate these controls to be implemented until 
after 2018. As we note above, these estimates of future visibility 
conditions presume that CSAPR continues to be implemented and is a 
viable alternative to source-specific BART. As discussed above, given 
the uncertainty arising from the remand of some of the state CSAPR 
budgets, we have determined it would not be appropriate to finalize the 
portion of our FIP relying on CSAPR as an alternative to SO2 
and NOX BART for EGUs in Texas. Should additional BART 
controls be required for any of the BART-eligible EGUs and should those 
controls in combination with other requirements on EGUs achieve 
emission reductions as of 2018 that are materially different than the 
emission reductions considered in quantifying the reasonable progress 
goals in this action, these reasonable progress goals would have to be 
revised at the same time any additional BART controls are proposed.
---------------------------------------------------------------------------

    \56\ Table 44 of our proposal (79 FR 74887) shows the additional 
visibility benefit anticipated from the scrubber retrofits. For 
Guadalupe Mountains, we estimate an additional 0.12 dv benefit on 
the 20% worst days based on 2018 projected background conditions 
resulting in a visibility goal of 16.14 dv if all required controls 
were in place by 2018. For Big Bend, we estimate an additional 0.09 
dv benefit on the 20% worst days based on 2018 projected background 
conditions resulting in a visibility goal of 16.48 dv if all 
required controls were in place by 2018. We note that Table 45 
provides the same visibility benefit estimates based on reducing 
recent actual emissions rather than 2018 CENRAP projected emission 
levels.
---------------------------------------------------------------------------

h. Revised Reasonable Progress Goals for the Wichita Mountains
    We are finalizing our technical analysis that was lacking in 
Oklahoma's development of reasonable progress goals for the Wichita 
Mountains, including appropriate consideration of emission reduction 
measures in Texas that Oklahoma should have asked Texas explicitly to 
obtain during its consultations with Texas. We are establishing new 
reasonable progress goals, as discussed in more detail in our proposal 
and FIP TSD,\57\ based on our technical analysis and accounting for the 
emission reductions required in Texas that we anticipate being in place 
by 2018. Consistent with our action regarding the Texas reasonable 
progress goals discussed in the previous section, our recalculated 
reasonable progress goals for 2018 in the table below reflect only the 
additional estimated visibility benefits from the required controls 
anticipated to be in place by 2018, which are the scrubber upgrades. 
While the required scrubber retrofits will provide for additional 
visibility improvement at the Class I areas,\58\ we do not anticipate 
these controls to be implemented until after 2018. As we note above, 
these estimates of future visibility conditions presume that CSAPR is a 
viable alternative to source-specific BART. As discussed earlier in 
this document, given the uncertainty arising from the remand of some of 
the state CSAPR budgets, we have determined it would not be appropriate 
to finalize the portion of our FIP relying on CSAPR as an alternative 
to source-specific SO2 and NOX BART for EGUs in 
Texas. Should additional BART controls in Texas ultimately be required 
for any of the BART-eligible EGUs and should those controls in 
combination with other requirements on EGUs achieve emission reductions 
as of 2018 that are materially different than the emission reductions 
considered in quantifying the reasonable progress goals for Oklahoma in 
this action, the reasonable progress goals would have to be revised at 
the same time any additional BART controls are proposed.
---------------------------------------------------------------------------

    \57\ See discussion beginning on 79 FR 74886, and section 13 of 
our FIP TSD.
    \58\ Table 44 of our proposal (79 FR 74887) shows the additional 
visibility benefit anticipated from the scrubber retrofits. For 
Wichita Mountains, we estimate an additional 0.30 dv benefit on the 
20% worst days based on 2018 projected background conditions 
resulting in a visibility goal of 21.03 dv if all required controls 
were in place by 2018. We note that Table 45 provides the same 
visibility benefit estimates based on reducing recent actual 
emissions rather than 2018 CENRAP projected emission levels.

  Table 6--Reasonable Progress Goals for 2018 for the Wichita Mountains
------------------------------------------------------------------------
                                                20% Best      20% Worst
                Class I Area                   days  (dv)    days  (dv)
------------------------------------------------------------------------
Wichita Mountains...........................          9.22         21.33
------------------------------------------------------------------------

II. Summary and Analysis of Major Issues Raised by Commenters

    We received both written and oral comments at the public hearings 
we held in Austin and Oklahoma City. We also received comments by the 
Internet and the mail. The full text of comments received from these 
commenters, except what was claimed as CBI, is included in the publicly 
posted docket associated with this action at www.regulations.gov. The 
CBI cannot be posted to www.regulations.gov, but is part of the record 
of this action. Our RTC document, which is also included in the docket 
associated with this action, provides detailed responses to all 
significant comments received, with the exception of those responses 
that rely on CBI and is a part of the administrative record for this 
action. The responses that rely upon CBI are in a separate document 
that is part of the record of this action but is not available for 
public review. In total, we received approximately 2,500 pages of 
significant comments. Below we provide a summary of the more 
significant comments received and a summary of our responses to them. 
Our RTC document is organized similarly to the structure present in 
this section (e.g., Cost, Modeling, etc.). Therefore, if additional 
information is desired concerning how we addressed a particular 
comment, the reader should refer to the appropriate section in the RTC 
document.

A. General Comments

    Comment: We received 4,500 comments in support of our rulemaking, 
specifically regarding the requirements that Texas coal-fired EGUs 
reduce SO2 emissions. These comments were from members 
representing various organizations, members of Congress, officials of 
government agencies, and members of the general public. At the public 
hearings in Austin, Texas, and Oklahoma City, Oklahoma, over 100 people 
expressed general support for the plan. The speakers at the public 
hearings included members of various organizations and members of the 
general public. Representatives of three Federal Land Management 
agencies also wrote comments in support of our action. Many of these 
same commenters also asked us to consider the impacts of NOX 
pollution and to consider additional coal-fired EGUs for control.
    Response: We thank the commenters for participating in the 
rulemaking and acknowledge their support of this action. We address 
NOX emissions in our modeling section below. We address the 
inclusion of additional coal-fired EGUs in our cost and modeling 
sections below.
    Comment: We received five comment letters and emails from citizens 
and a representative from one organization that stated general 
opposition.
    Response: These comments were too general to give us a basis for a 
specific response. Please see our detailed responses in this action and 
additional

[[Page 308]]

detail in our RTC document, in which we provide substantial 
explanations and reasons for disapproving elements of the Texas and 
Oklahoma SIPs and finalizing our FIP.
    Comment: As a general matter, a number of commenters took issue 
with our usages of the terms ``reasonable'' and ``significant'' as used 
in our proposal and TSDs and contended they were inappropriate or 
extra-statutory terms.
    Response: We consider the general use of ``reasonable'' and 
``significant'' in this action to be appropriate. The word 
``reasonable'' is not extra-statutory in this action because it is part 
of the statutory term ``reasonable progress,'' see CAA ection 169A(g). 
In turn, ``significant'' may be used according to its ordinary meaning 
(as in our reference above to ``significant comments''). This word is 
elsewhere employed consistent with our guidance and previous actions. 
See, e.g., our Reasonable Progress Guidance at 3-2. These terms are 
generally used in rulemaking actions, including use by Texas and 
Oklahoma in their regional haze actions.\59\ We use these terms 
appropriately throughout this rulemaking action, for example, when 
explaining it was ``reasonable'' to expect great variation in the 
effectiveness of emission reductions between two sources given the 
difference in distances between these two facilities and the Class I 
areas, or when describing CENRAP visibility modeling as demonstrating 
that a ``significant'' portion of the visibility impacts to Class I 
areas in a number of states on the worst 20% days for both 2002 and 
2018 were attributable to Texas sources.\60\
---------------------------------------------------------------------------

    \59\ See, e.g., our proposal at 79 FR 74844 (noting our 
agreement with ``Texas' determination that was not reasonable to 
request additional controls from other states at this time'') and 
74823 (describing how Oklahoma's response to public comments on its 
regional haze SIP ``acknowledged that sources in Texas had 
significant impacts on visibility in Wichita Mountains, but 
maintained that it did not have the regulatory authority to require 
emission reductions in other states'').
    \60\ 79 FR 74841 and 74854.
---------------------------------------------------------------------------

B. State and Federal Roles in the Regional Haze Program

    Some commenters argued that our proposal to disapprove Texas' and 
Oklahoma's regional haze SIPs disregarded the primary role of the 
states under the CAA, the Regional Haze Rule, and relevant case law. We 
do not agree. Congress designed the CAA to provide for states to take 
the lead in developing SIPs but also required EPA to review SIPs for 
compliance with statutory and regulatory requirements. We recognize 
that states have the primary responsibility of drafting a SIP to 
address the requirements of the regional haze program. We also 
recognize that we have the responsibility of ensuring that the state 
plans, including regional haze SIPs, conform to the CAA requirements. 
We have determined that the Texas and Oklahoma SIPs do not meet certain 
elements of these Federal requirements and are accordingly partially 
disapproving these SIPs.
    Additionally, our review of SIPs is not limited to a ministerial 
review and approval of a state's decisions. Some commenters argued that 
the principles of cooperative Federalism in the CAA require EPA to 
defer to states in their development of SIPs, so long as necessary 
statutory requirements are met. Commenters stated that our proposal 
ignores such limits and would impose FIPs that ignore the primary 
implementation role given to Texas and Oklahoma. We disagree with the 
commenters' arguments regarding cooperative Federalism. Under this 
framework, the CAA directs us to act if a state fails to submit a SIP, 
submits an incomplete SIP, or submits a SIP that does not meet the 
statutory requirements. Thus, the CAA provides us with a critical 
oversight role in ensuring that SIPs meet the CAA's requirements.
    Commenters stated that Texas' plan was complete by operation of 
law, met all requirements, and that we had no authority to impose a 
FIP. We disagree. The commenters confuse the action of merely 
submitting a SIP and having it deemed complete with the action of 
submitting a SIP that complies with the applicable Federal 
requirements. We agree that the CAA gives each state flexibility in 
developing a SIP, but in doing so, it must ensure the SIP meets Federal 
requirements. We must review the state's SIP and determine whether it 
meets such Federal requirements. If it does not, we must disapprove it 
(or portions thereof), and adopt a FIP to address the disapproved 
parts. In undertaking such a review, we do not ``usurp'' the state's 
authority arbitrarily, as some commenters stated, but rather we ensure 
that such authority is reasonably exercised. In this instance, portions 
of the states' SIPs were not approvable for reasons discussed elsewhere 
in this document, the responses to comments, and the proposed 
rulemaking.
    Some commenters argued that the appropriate remedy for a 
substantially inadequate plan under our Regional Haze Rule is periodic 
updates, as opposed to a FIP. We disagree. The Regional Haze Rule's 
requirements for comprehensive periodic revisions (see 40 CFR 
51.308(f)) and periodic progress reports (see 40 CFR 51.308(g)) are 
very different from the authority to impose a FIP when there is a 
determination that a SIP is not approvable. As we have stated 
elsewhere, we have the authority and obligation to impose a FIP to fill 
in such gaps. The provisions of the Regional Haze Rule regarding 
states' ongoing responsibility to periodically revise their regional 
haze SIPs do not override this responsibility.

C. Our Clarified Interpretation of the Reasonable Progress and Long-
Term Strategy Requirements

    Several commenters criticized the aspect of our proposal that 
provided potential commenters and states with clarification regarding 
our interpretation of the reasonable progress and long-term strategy 
provisions found at 40 CFR 51.308(d)(1) and (3). Some of these 
commenters alleged that our proposal did not clarify an existing 
interpretation, but rather outlined a new one that was being applied to 
Texas and Oklahoma after the fact. They argued that the provisions in 
question require upwind states to include in their long-term strategy 
only those measures necessary to achieve the reasonable progress goals 
set by downwind states, regardless of whether the goals were based on 
sound analyses and adequate interstate consultation or reflect all 
reasonable control measures. Some commenters argued that upwind states 
have no obligation to conduct four-factor analyses with respect to 
downwind Class I areas at all. In essence, these commenters asserted 
that the only obligation that the CAA and Regional Haze Rule impose 
upon upwind states is a requirement to consult with their neighbors and 
make good on any commitments made during the consultation process. They 
further argued that their preferred interpretation is mandated by the 
plain language of the Regional Haze Rule, such that the interpretation 
laid out in our proposal is plainly erroneous and not entitled to 
judicial deference. Other commenters asserted the opposite. They agreed 
with our clarifications and argued that our interpretation of the 
provisions found at 40 CFR 51.308(d)(1) and (3) is not only reasonable, 
but mandated by the CAA and the plain language of the provisions 
themselves.
    After carefully considering these comments, we stand by our 
clarified interpretation as outlined in the proposal. The alternative 
interpretations offered by some of the commenters are not in accord 
with the plain language of CAA sections 169A(b)(2) and (g)(1),

[[Page 309]]

which require both upwind and downwind states to include in their SIPs 
``emission limits, schedules of compliance and other measures as may be 
necessary to make reasonable progress toward the national goal'' and to 
determine what controls are necessary to make reasonable progress by 
considering the four statutory factors. The commenters' view that 
upwind states are not required to conduct four-factor analyses for 
downwind Class I areas is inconsistent with Texas' own view of the 
requirements of the CAA and the Regional Haze Rule. Texas itself 
conducted a four-factor analysis for downwind Class I areas (albeit a 
flawed one) and stated in its own response-to-comments document that it 
was required to do so.\61\ Indeed, the commenters' alternative 
interpretations are premised largely on a fundamental misunderstanding 
of the regional haze planning process. The commenters seem to suggest 
that states set their reasonable progress goals first and then 
determine what controls are necessary to achieve them. In their view, 
if a downwind state sets a reasonable progress goal that does not 
assume emission reductions from an upwind state, then the upwind state 
has no obligation to include control measures in its long-term 
strategy. Such an interpretation is not consistent with the CAA, our 
regulations and guidance, or how such analyses are conducted in 
reality. To set their reasonable progress goals, states consider the 
anticipated visibility conditions at a Class I area in a future year. 
In order to do so, they must first determine the level of emission 
reductions that will result once the control measures necessary to make 
reasonable progress are installed and estimate the visibility benefit 
anticipated from those reductions. In determining the control measures 
necessary to make reasonable progress, states must conduct four-factor 
analyses, considering costs and other factors. If an upwind state were 
not required to participate or if emission reductions from upwind 
sources were not considered in this process, there would be no way for 
downwind states to set reasonable progress goals that account for all 
reasonable control measures.
---------------------------------------------------------------------------

    \61\ See, e.g., Appendix 2-2 to the Texas Regional Haze SIP at 
24 (``Further, a four-factor analysis is necessary for the set of 
sources in the respective areas of influence that impact each of the 
Class I areas that Texas' emissions impact.'') (emphases added) 
(``The TCEQ has used the four-factor analysis, as required, for the 
set of Texas sources impacting Class I areas, to determine whether 
all reasonable reductions have been required.'') (emphasis added).
---------------------------------------------------------------------------

D. Consideration of Visibility in the Reasonable Progress Analysis

    Comment: Many commenters maintained that, unlike with BART, 
visibility is not one of the statutory or regulatory factors that 
states must consider in determining reasonable progress and setting 
reasonable progress goals. As a result, some commenters argued that EPA 
is not permitted to disapprove a state's four-factor analysis based on 
the manner in which a state considered visibility impacts or visibility 
benefits in determining reasonable progress. They argued that EPA's 
statutory role does not extend to dictating ``how'' a state considers 
the four factors, especially considering the flexibility states have 
when determining reasonable progress. Other commenters asserted that 
EPA placed too much weight on visibility, a non-statutory factor, in 
analyzing Texas' SIP and in promulgating a FIP. Some commenters alleged 
that states and EPA were barred from considering visibility in a 
reasonable progress analysis altogether. Several commenters suggested 
that, had we not considered visibility benefits when promulgating a FIP 
for Texas, we would not have required any SO2 controls. One 
commenter cited to WildEarth Guardians v. EPA \62\ to support its 
contention that neither the CAA nor the Regional Haze Rule requires 
source-specific analysis in the determination of reasonable progress. 
Other commenters cited to American Corn Growers Ass'n v. EPA \63\ to 
support their assertion that we impermissibly isolated visibility as a 
factor and in so doing constrained authority Congress conferred on the 
states.
---------------------------------------------------------------------------

    \62\ WildEarth Guardians v. EPA, 770 F.3d 919 (10th Cir. 2014).
    \63\ Am. Corn Growers Ass'n v. EPA, 291 F.3d 1 (D.C. Cir. 2002).
---------------------------------------------------------------------------

    Response: We disagree with these comments. The commenters appear to 
be stating that states (or EPA when promulgating a FIP) either cannot 
or need not consider visibility in any way in determining reasonable 
progress and that we therefore must approve a state's reasonable 
progress goals and long-term strategy as long as all four mandatory 
reasonable progress factors are analyzed to some degree. This view is 
at odds with the overarching purpose of the CAA's visibility 
provisions. Congress declared as a national goal in CAA section 
169A(a)(1) the ``prevention of any future, and the remedying of any 
existing, impairment of visibility in mandatory Class I Federal areas 
which impairment results from manmade air pollution.'' CAA section 
169A(b)(2) required the Administrator to promulgate regulations to 
assure ``reasonable progress toward meeting the national goal.'' Thus, 
the entire purpose of the reasonable progress mandate is to achieve the 
national goal of natural visibility conditions at each Class I area.
    CAA section 169A(g)(1) goes on to state that, in determining 
``reasonable progress,'' states must consider four factors: ``the costs 
of compliance, the time necessary for compliance, and the energy and 
nonair quality environmental impacts of compliance, and the remaining 
useful life of any existing source subject to such requirements.'' This 
consideration is commonly referred to as the ``four-factor analysis.'' 
\64\ The crux of the commenter's argument seems to be that, because 
this list of factors does not include visibility, states can ignore 
visibility altogether or, if they choose, consider it in any fashion 
they want.
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    \64\ Correspondingly, under Sec.  51.308(d)(1) of the Regional 
Haze Rule, promulgated in response to this mandate, states must 
``establish goals (expressed in deciviews) that provide for 
reasonable progress towards achieving natural visibility 
conditions'' for each Class I area within a state. Reasonable 
progress goals are interim goals that represent measurable, 
incremental visibility improvement over time toward the goal of 
natural visibility conditions. Section 51.308(d)(1)(i)(A) requires 
states to consider the four statutory factors when establishing 
their reasonable progress goals.
---------------------------------------------------------------------------

    While we agree that visibility is not one of the four mandatory 
factors explicitly listed for consideration in CAA section 169A(g)(1) 
or 40 CFR 51.308(d)(1)(i)(A), the term ``reasonable progress'' itself 
means reasonable progress towards the national goal of natural 
visibility conditions. The Supreme Court has stated that, ``[i]n 
determining whether Congress has specifically addressed the question at 
issue, a reviewing court should not confine itself to examining a 
particular statutory provision in isolation. The meaning--or 
ambiguity--of certain words or phrases may only become evident when 
placed in context. It is a `fundamental canon of statutory construction 
that the words of a statute must be read in their context and with a 
view to their place in the overall statutory scheme.' A court must 
therefore interpret the statute `as a symmetrical and coherent 
regulatory scheme' and `fit, if possible, all parts into an harmonious 
whole.' '' \65\
---------------------------------------------------------------------------

    \65\ FDA v. Brown & Williamson Tobacco Corp., 529 U.S. 120, 132-
33 (2000) (quoting Davis v. Michigan Dept. of Treasury, 489 U.S. 
803, 809 (1989), Gustafson v. Alloyd Co., 513 U.S. 561, 569 (1995), 
and FTC v. Mandel Brothers, Inc., 359 U.S. 385, 389 (1959)).
---------------------------------------------------------------------------

    To ensure a coherent regulatory scheme, we believe that states (or 
EPA when promulgating a FIP) can consider

[[Page 310]]

visibility when determining reasonable progress in at least two ways. 
First, states can consider the visibility impacts of sources when 
determining what sources to analyze under the four-factor framework. 
CAA section 169A(b)(2) does not provide any direction regarding which 
sources or source categories a state should analyze when determining 
reasonable progress. Similarly, CAA section 169A(g)(1) refers to ``any 
existing source subject to such requirements,'' but unlike the BART 
provisions, does not identify which existing sources or source 
categories should be subject to reasonable progress requirements. Given 
this statutory ambiguity, we believe that allowing states to consider 
visibility impacts when determining the scope of the reasonable 
progress analysis is a reasonable interpretation of the statute ``as a 
harmonious whole.'' Accordingly, states can develop screening metrics 
that target those sources with the greatest visibility impacts for 
further analysis. Our 2007 guidance advocated this approach, and nearly 
all states, including Texas, used metrics like Q/d to consider the 
potential visibility impacts of their sources and screen out those 
sources with low visibility impacts.\66\ We followed this same approach 
in our FIP by using both Q/d and a second metric based on a source's 
modeled percent contribution to total visibility impairment at impacted 
Class I areas. If states or we could not consider visibility impacts as 
a way of identifying which sources should be considered for additional 
controls, then states would have no rational way to differentiate 
between hundreds of sources that vary in distance from Class I areas, 
emit different visibility impairing pollutants in varying amounts, and 
are subject to diverse meteorological conditions that affect the 
transport of visibility-impairing pollutants. The result would be a 
cumbersome analysis encompassing hundreds of sources (or in the case of 
Texas, well over a thousand), many of which may have little if any 
impact on visibility in Class I areas. Congress could not have intended 
such an incongruous result.
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    \66\ For example, in VISTAS states, to select the specific point 
sources that would be considered for each Class I area, VISTAS first 
identified the geographic area that was most likely to influence 
visibility in each Class I area and then identified the major 
SO2 point sources in that geographic area. The distance-
weighted point source SO2 emissions (Q/d) were combined 
with the gridded extinction-weighted back-trajectory residence 
times. The distance-weighted (Q/d) gridded point source 
SO2 emissions were then multiplied by the total 
extinction-weighted back-trajectory residence times on a cell-by-
cell basis and then normalized. VISTAS Area of Influence Analyses, 
2007, is available in the docket for this action.
---------------------------------------------------------------------------

    Second, once a universe of sources has been identified for 
analysis, we believe that states can consider the visibility 
improvement that will result from potential control options when 
weighing the four statutory factors. Allowing consideration of 
visibility improvement is appropriate for several reasons. Most 
importantly, it aligns with Congress' national goal, which is to remedy 
existing impairment of visibility in Class I areas. While section 
169A(g)(1) of the CAA contains a list of factors states must consider 
when determining reasonable progress, we do not believe that list is 
exclusive. As the Eighth Circuit Court acknowledged in North Dakota v. 
EPA, states can take visibility improvement into account when 
evaluating reasonable progress controls so long as they do so in a 
reasonable way.\67\ We have iterated this position in previous regional 
haze actions. For example, in our final rule on the Montana regional 
haze SIP, we stated, ``We agree that visibility improvement is not one 
of the four factors required by CAA section 169A(g)(1) and 40 CFR 
51.308(d)(1)(i)(A), however, it (along with other relevant factors) can 
be considered when determining controls that should be required for 
reasonable progress.'' \68\ Similarly, in our final rule on the Arizona 
regional haze SIP, we concluded that, ``while visibility is not an 
explicitly listed factor to consider when determining whether 
additional controls are reasonable, the purpose of the four-factor 
analysis is to determine what degree of progress toward natural 
visibility conditions is reasonable. Therefore it is appropriate to 
consider the projected visibility benefit of the controls when 
determining if the controls are needed to make reasonable progress.'' 
\69\
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    \67\ North Dakota v. EPA, 730 F.3d 750, 766 (8th Cir. 2013).
    \68\ 77 FR 57864, 57899, 57901; see also Montana Proposed Rule, 
77 FR 23988, 24062.
    \69\ 79 FR 9318 n.137 (finalized based on this same reasoning at 
79 FR 52420); TX TSD at 7 n.6; FIP TSD at 12; 79 FR 74874.
---------------------------------------------------------------------------

    Further, allowing states to consider visibility improvement 
alongside the four statutory factors ensures that only those cost-
effective controls that will achieve reasonable visibility benefits are 
required during each phase towards the national goal. If states were 
not permitted to consider visibility improvement when conducting their 
control determinations, then states arguably would have to require all 
cost-effective controls during the first planning period (assuming no 
limiting energy or non-air quality environmental impacts) regardless of 
whether some of those controls would be far more beneficial than 
others.\70\ Oddly, some of the commenters appear to be suggesting that, 
if we had not considered visibility benefits in our analysis, we would 
not have controlled certain sources. On the contrary, we decided not to 
require certain cost-effective controls in this planning period because 
they would not achieve as much benefit as other controls. If these 
commenters are correct and the consideration of visibility benefits is 
impermissible in a four-factor analysis, then we would have required 
all cost-effective controls, including those at the Parish and Welsh 
facilities.
---------------------------------------------------------------------------

    \70\ We also note that practical implementation concerns could 
arise if a state as large and source-numerous as Texas required all 
cost-effective controls at once.
---------------------------------------------------------------------------

    We also note that Congress did not provide any direction as to how 
states should consider ``the costs of compliance'' when determining 
reasonable progress. One permissible way a state could ``consider'' 
costs is to compare them to prospective benefits. In other words, we 
believe the first statutory factor is capacious enough to allow for a 
comparison of cost-effectiveness to visibility improvement. Finally, we 
note that our 2007 guidance explicitly permits states to consider other 
relevant factors when conducting a four-factor analysis,\71\ and many 
states, including Texas, did so. In conclusion, we believe that states 
are permitted, but not required, to consider visibility improvement 
alongside the four statutory factors when making their reasonable 
progress determinations, with the important caveat that they must do so 
in a reasonable fashion.
---------------------------------------------------------------------------

    \71\ ``In determining reasonable progress, CAA Section 
169A(g)(1) requires States to take into consideration a number of 
factors. However, you have flexibility in how to take into 
consideration these statutory factors and any other factors that you 
have determined to be relevant.'' 2007 Guidance at 2-3, 4-2, and 5-
1.
---------------------------------------------------------------------------

    Some commenters alluded that visibility improvement is irrelevant 
to a four-factor analysis because Congress did not include it as one of 
the four factors, but did include it as a factor to be considered in 
determining BART. We do not find this reasoning to be persuasive. The 
sources that Congress subjected to the BART requirement (i.e., sources 
grandfathered from the PSD requirement) were not necessarily sources 
that would have an impact on visibility impairment. As such, Congress 
included specific language in CAA sections 169A(b)(2)(A) and 169A(g)(2) 
to ensure that only those grandfathered sources that cause or 
contribute to visibility impairment and that would

[[Page 311]]

result in visibility improvement if controlled would be required to 
install BART. On the other hand, the national goal of achieving natural 
visibility conditions is central to the notion of reasonable progress, 
so Congress had no need to include language regarding visibility 
improvement in CAA section 169A(g)(1).
    We also disagree with the commenters that we cannot disapprove a 
state's SIP where the state has considered visibility improvement in an 
unreasonable fashion. As the Eighth Circuit explained in North Dakota, 
``[a]lthough the state was free to employ its own visibility model and 
to consider visibility improvement in its reasonable progress 
determinations, it was not free to do so in a manner that was 
inconsistent with the CAA.'' \72\ Like the State of North Dakota, Texas 
chose to evaluate visibility improvement alongside the four statutory 
reasonable progress factors, but did so in an unreasonable way. We 
discuss several ways that Texas' consideration of visibility 
improvement in its reasonable progress determinations was unreasonable 
elsewhere in this document, in our proposal, and in our Texas TSD.\73\ 
One point worth mentioning here, however, is that Texas estimated the 
visibility improvement of potential controls by making comparisons to 
degraded background conditions instead of to natural background 
conditions, which is precisely the same mistake that North Dakota 
made.\74\ The end result of this and other errors in Texas' analysis 
was that Texas unreasonably concluded that the total cost of additional 
controls was not worth the visibility benefits of those controls and 
that no additional controls were reasonable for this planning 
period.\75\ We are appropriately disapproving this portion of Texas' 
SIP. The fact that Texas' decision to evaluate visibility improvement 
was ``discretionary'' does not mean that Texas was free to exercise 
that discretion in an unreasonable manner.
---------------------------------------------------------------------------

    \72\ North Dakota, 730 F.3d at 766.
    \73\ See Section B.2 of the Texas TSD and Section V.C.3 of our 
proposal (79 FR 74818).
    \74\ In contrast, Texas conducted a proper visibility analysis 
using natural background conditions elsewhere in its SIP when the 
state assessed the visibility impacts of its BART sources. See Texas 
Regional Haze SIP, Appendix 9-5 at 2-11 (``The source's HI [haze 
index] is compared to natural conditions to assess the significance 
of the source's visibility impact. EPA guidance lists natural 
conditions (bnatural) by Class I area in terms of Mm-\1\ 
(EPA, 2003b) and assumes clean conditions with no anthropogenic or 
weather interference. The visibility significance metric for 
evaluating BART sources is the change in deciview (del-dv) from the 
source's and natural conditions haze indices.'').
    \75\ Texas concluded, ``At a total estimated cost exceeding $300 
million and no perceptible visibility benefit, Texas has determined 
that it is not reasonable to implement additional controls at this 
time.'' Texas regional haze SIP at 10-7.
---------------------------------------------------------------------------

    We note that the Tenth Circuit's decision in WildEarth Guardians v. 
EPA does not address the issues present in this case. There, the Tenth 
Circuit Court merely held that the CAA does not require a state to 
conduct a source-specific reasonable progress analysis. The Court did 
not hold that a state is free to conduct any type of analysis 
irrespective of whether or not the analysis is reasonable. Nor did the 
Court hold that the CAA prevents states or the EPA from conducting a 
source-specific analysis if that approach is determined to be 
appropriate.
    Finally, we disagree with the commenter that we elevated visibility 
improvement to a place of primary importance, either in disapproving 
Texas' SIP or in promulgating our FIP. The flaws with Texas' 
consideration of visibility benefits were only one aspect of our 
disapproval. Moreover, we stated on multiple occasions in our proposal 
that we considered all four statutory factors in our analysis. Our 
analysis does not give greater weight to one factor over another; 
rather, we considered all four factors fully, revealing that the cost 
factor, which included visibility improvement consideration, was the 
most determinative in our decisions. The American Corn Growers Ass'n v. 
EPA case is inapposite. There, the D.C. Circuit Court faulted how EPA 
assessed the statutory fifth factor of visibility improvement in a BART 
determination (not a reasonable progress determination) by using a 
regional, multi-source, group approach to assessing the visibility 
improvement factor, while assessing the other four statutory BART 
factors on a source-specific basis. Here, not only is the analysis at 
issue not being performed under BART, but we did not give greater 
weight to our consideration of visibility improvement within the cost 
factor, or consider the cost factor in a different fashion from the 
other three reasonable progress factors.
    Comment: Some commenters stated that regional haze is the 
contribution of numerous emission sources to visibility impairment and 
that, while the contribution from any single source may be 
``insignificant,'' the aggregate impact from all sources is 
significant. These commenters argued that, by using the Q/d screening 
metric, the EPA already took potential visibility impacts (and benefits 
of control) into account. They argued that the EPA cannot use 
visibility again during the four-factor analysis as an ``off-ramp'' to 
not control a source. Furthermore, the EPA should not break a facility 
down into its constituent parts because doing so can diminish each 
individual impact to the point where it becomes relatively 
insignificant. Such a ``divide and exempt'' approach is contrary to 
Congress' goal that Class I areas eventually return to natural 
visibility conditions. One commenter stated that the EPA should have 
conducted four-factor analyses for all 38 facilities identified in the 
Q/d analysis.
    Response: We agree that regional haze is, by definition, visibility 
impairment caused by numerous emission sources. We also agree that, 
while some sources may have very small visibility impacts, aggregate 
impacts can be significant. However, while there are undoubtedly 
thousands of sources within Texas that individually have small 
contributions to regional haze, there are also many sources that, even 
in isolation, have relatively large visibility impacts. In this first 
planning period, we identified the most significant sources that impact 
visibility, determined whether cost-effective controls were available 
for these sources, and balanced the costs of those controls against 
their visibility benefits. As we discussed in more detail above, if we 
had adopted the commenters' suggestion and controlled all large sources 
where cost-effective controls were available, we likely would have 
controlled many additional sources. Given the iterative nature of the 
regional haze program, we think that it was a reasonable approach to 
require only those cost-effective controls with the largest benefits 
this planning period. We expect that Texas will control additional 
sources, which by then will be the largest contributors to impairment, 
during future planning periods.
    As we explain further in supporting documents, we also disagree 
with the commenter's suggestion that we should have screened only by 
using the Q/d metric. A Q/d analysis compares a source's emissions and 
distance to nearby Class I areas to provide an initial estimate of the 
potential visibility impacts of those sources. After conducting our Q/d 
analysis, we then used photochemical modeling to estimate the 
visibility impacts of this set of sources in a much more refined manner 
that accounts for chemistry, meteorological conditions, and stack 
parameters in addition to emissions and location. The results of our 
modeling indicated that a subset of 38 facilities were the primary 
contributors to visibility impairment at each Class I area. We then 
used the modeling results to narrow the group of sources further 
because it was reasonable to conduct a

[[Page 312]]

full four-factor analysis only for the subset of sources with the 
largest facility-and unit-level visibility impacts, as described in 
detail in our supporting documents.

E. Consultation Between Oklahoma and Texas

    Comment: The regulations require that Texas' long-term strategy 
reflect the emission reductions requested and agreed to by the CENRAP 
states. EPA points to no flaws in the CENRAP regional planning process 
in which Texas and Oklahoma participated together. The EPA asserts that 
the TCEQ should have provided information necessary to identify 
reasonable reductions, which the Regional Haze Rule does not require. 
Oklahoma did not request additional controls on Texas sources or 
disagree with Texas' determination that no additional controls were 
warranted during the first planning period.
    Nonetheless, the EPA arbitrarily disapproved the Texas consultation 
process with Oklahoma without reference to its rules, guidance, and 
prior SIP approvals. The proposal never details what information 
Oklahoma lacked in establishing its reasonable progress goals, and EPA 
must provide a more adequate explanation of how additional information 
would have changed Oklahoma's ultimate determination that additional 
controls on Texas sources would not move the Wichita Mountains 
perceptibly closer to its regional haze goals.
    Response: We disagree that participation alone in a Regional 
Planning Organization (RPO) process (here CENRAP) will always be enough 
to meet the requirements for consultation under the Regional Haze Rule. 
The rule does not negate the requirement that a state have a complete 
and technically adequate analysis so that consultations are well 
informed. The RPOs, such as CENRAP, provided technical analyses, 
including emission inventory development and air quality modeling to 
project future visibility conditions and additional information on 
sources of visibility impairment to facilitate consultations and 
support the development of the states' regional haze SIPs.
    Although Texas participated in CENRAP, it retained the duty to do 
whatever additional analysis was necessary to fully address the 
requirements of the Regional Haze Rule for addressing its long-term 
strategy and setting its reasonable progress goals. While the long-term 
strategy requirements allow a state to rely on the RPO technical 
analysis, that is true only to the extent it provides the necessary 
information. A state must address any gaps in that analysis. For Texas, 
inadequate information existed not only for the reasonable progress 
analysis for its own Class I areas, but also for the long-term strategy 
development for addressing significant impacts at the Wichita 
Mountains. CENRAP was not required, nor did it provide state-specific 
analyses and information on the cost-effectiveness and visibility 
benefits of potential control strategies under consideration by each 
state to address the specific sources or groups of sources within that 
state that have the largest visibility impacts. Rather, CENRAP provided 
more general information on overall projected visibility conditions, 
potential controls and associated costs for some sources and the 
potential benefit of regional emission reductions to inform the 
development of potential control strategies that may require additional 
analysis.\76\ For example, while the CENRAP analysis identified that 
impacts from EGUs in Texas were significant, it did not provide a 
refined analysis to fully assess the cost-effectiveness and visibility 
benefits of controlling those sources, including not providing 
information on the cost-effectiveness of scrubber upgrades for those 
sources with existing, underperforming scrubbers. As Texas states in 
its regional haze SIP, ``While Texas participates in CENRAP and 
benefits from the technical work coordinated by the RPO, Texas has sole 
responsibility and authority for the development and content of its 
Regional Haze SIP.'' \77\
---------------------------------------------------------------------------

    \76\ CENRAP conducted a control sensitivity analysis to evaluate 
the impact of point source emission reductions across all CENRAP 
states given a maximum dollar per control level of $5,000/ton; 
however, the results ``were intended to be a starting point for 
control discussions that would require much greater refinement.'' 
Technical Support Document for CENRAP Emissions and Air Quality 
Modeling to Support Regional Haze State Implementation Plans, 
September 12, 2007 at 2-37).
    \77\ 2009 Texas Regional Haze SIP at 3-1.
---------------------------------------------------------------------------

    Recognizing that the information made available by CENRAP indicated 
the significant impact of Texas emissions and potential for cost-
effective controls, Texas used the CENRAP analysis as a starting point, 
and performed supplemental analysis for both its reasonable progress 
and long-term strategy demonstrations. However, that additional 
technical analysis performed by Texas was flawed and therefore did not 
provide the type of information necessary to fully evaluate the 
reasonableness of controls at Texas sources with the largest potential 
to impact visibility at its own Class I areas and the Wichita 
Mountains. Allowing this lack of adequate information to continue was a 
critical misstep for ODEQ in setting its reasonable progress goals, and 
a critical misstep for Texas when determining its fair share of 
emissions reductions under the long-term strategy requirement. The 
plain language of the CAA requires that states consider the four 
factors used in determining reasonable progress in developing the 
technical basis for the reasonable progress goals both in their own 
Class I areas and downwind Class I areas. Such documentation is 
necessary so that interstate consultations can proceed on an informed 
basis, and so that downwind states can properly assess whether any 
additional upwind emissions reductions are necessary to achieve 
reasonable progress at their Class I areas. Therefore, Texas had an 
obligation to provide appropriate information to Oklahoma so it could 
establish a proper progress goal for the Wichita Mountains. Further, 
Texas had an obligation to conduct an appropriate technical analysis, 
and demonstrate through that analysis (required under paragraph 
(d)(3)(ii)), that it provided its fair share of emissions reductions to 
Oklahoma. In summary, Texas was required through the consultation 
process to provide Oklahoma the information it needed to establish its 
reasonable progress goals for the Wichita Mountains, and it failed to 
do so.
    Comment: Oklahoma possessed more than adequate information about 
impacts and potential controls but correctly decided it was not 
reasonable to request any further reductions from Texas sources during 
the first planning period. Oklahoma was in agreement with Texas on the 
goal and measures for the Wichita Mountains. EPA may disagree with that 
choice in hindsight and may wish Oklahoma's and Texas' agreement was 
different, but that is an unlawful basis for disapproving Oklahoma's 
reasonable progress consultation with Texas and disapproving Oklahoma's 
reasonable progress goals.
    Response: While we agree that Oklahoma possessed more than adequate 
information from the CENRAP analyses about impacts from Texas sources 
at a certain level of aggregation, and some knowledge concerning 
potential controls for some of these sources, we do not agree that it 
was reasonable for Oklahoma to stop at this point. Despite the 
information it did have, Oklahoma never explicitly asked Texas for 
reductions even though there was clear evidence from the CENRAP 
analyses that Texas sources, particularly EGUs in northeast Texas, were

[[Page 313]]

significantly impacting the Wichita Mountains and that cost-effective 
controls were likely available on some of these sources.
    The Regional Haze Rule required that Oklahoma use the consultation 
process under 40 CFR 51.308(d)(1)(iv) in the development of reasonable 
progress goals in tandem with Texas. Nevertheless, throughout the 
consultations, Oklahoma failed to explicitly request that Texas further 
investigate whether reasonable controls were available or that Texas 
reduce emissions from these significantly impacting sources to ensure 
that all reasonable measures to improve visibility were included in 
Texas' long-term strategy and incorporated into Oklahoma's reasonable 
progress goals for the Wichita Mountains. This failure resulted in the 
development of improper reasonable progress goals for the Wichita 
Mountains.
    Comment: Even if EPA's disapproval of Oklahoma's reasonable 
progress goals were authorized and supported, that disapproval does not 
allow EPA to disapprove Texas' long-term strategy. Regardless of EPA's 
view of Oklahoma's reasonable progress goals for the Wichita Mountains, 
it is undisputed that Texas' SIP includes the measures necessary to 
secure Texas' agreed-to apportionment of emission reductions to meet 
the reasonable progress goals for the Wichita Mountains established by 
Oklahoma, and thus EPA must approve Texas' SIP.
    Response: We disagree that disapproval of Oklahoma's reasonable 
progress goals for the Wichita Mountains does not allow us to 
disapprove Texas' long-term strategy. We are disapproving the Texas 
long-term strategy because the analysis underlying it is technically 
flawed. Because of these flaws, Texas' SIP submittal does not include 
all the measures necessary to secure its apportionment of the emission 
reductions needed to meet the progress goal that should account for all 
reasonable control measures for the Wichita Mountains, or its own Class 
I areas. We are disapproving the Oklahoma reasonable progress goals for 
the Wichita Mountains not because of the technically flawed Texas long-
term strategy, but because Oklahoma's consultations with Texas were 
flawed, which prevented it from adequately developing its reasonable 
progress goals for the Wichita Mountains. Also, because Oklahoma's 
consultations with Texas were flawed, Oklahoma did not adequately 
consider the emission reduction measures necessary to achieve the 
uniform rate of progress for the Wichita Mountains and did not 
adequately demonstrate that the reasonable progress goals it 
established were reasonable based on the four statutory factors. See 
our previous responses concerning the comments on Texas allegedly 
meeting the ``agreed-to apportionment.''
    Comment: EPA never raised any of the concerns it asserts and it 
never second-guessed the process or the data that the states were 
developing--as it does now, years after that process has been completed 
and on the eve of the next planning period. In truth, Texas and 
Oklahoma did exactly what EPA encouraged them to do.
    Response: Our task under the CAA is to review a SIP once it is 
formally submitted by the state and determine if it meets the CAA and 
our rules. There is no requirement in the CAA that we must review, 
evaluate, and comment on a state's proposed SIP revision before it is 
formally submitted to us. Nevertheless, we note that we sent comment 
letters to Texas and Oklahoma during their public comment periods, 
raising many of the issues presented herein. We stated that Texas 
should specifically demonstrate that it included all measures necessary 
to obtain its share of the emission reductions necessary for achieving 
reasonable progress in the Wichita Mountains and document its technical 
basis. Furthermore, we stated that the Texas reasonable progress/long-
term strategy technical analysis raised concerns about whether it 
appropriately evaluated whether there were additional reasonable 
controls available to help reduce its impact on the Wichita Mountains. 
For Oklahoma, we stated it did not appear that ODEQ actually requested 
reductions from Texas and we urged Oklahoma to ensure Texas was aware 
of its sources' impact and encourage reductions as necessary. In both 
letters, we stated that additional concerns would surface during the 
review of the final SIP submittals.
    Comment: EPA's consultation disapprovals of Oklahoma and Texas are 
the first time EPA has disapproved a state regional haze consultation. 
This new approach of second-guessing regional agreements--years after 
they are reached and implemented--would undermine and chill the 
regional planning process, and discourage states from participating.
    Response: We disagree that this is a new approach on the 
consultation requirements and we also disagree that our position 
undermines or chills the regional planning process. While our 
regulations allow states to work together in RPOs, like CENRAP, this is 
not a stopping point for states to fall back on as a rationale not to 
meet the CAA and Regional Haze Rule. We have not disapproved other 
states' reasonable progress/long-term strategy consultation processes 
because the particular facts of the situation for Texas and Oklahoma 
did not arise. We believe our clarification that upwind states have an 
obligation to reasonably assess potential control measures to address 
impacts in Class I areas in downwind states will encourage states to 
work together to address regional haze.

F. Source Category and Individual Source Modeling

    Comment: EPA proposed to disapprove Texas' regional haze SIP 
because EPA determined that Texas was required to conduct a source-
specific analysis of certain facilities to meet the reasonable progress 
requirements. EPA guidance and judicial precedent have stated that a 
source-specific analysis or source-by-source demonstration is not 
required to determine reasonable progress.
    Response: We disagree with these comments as our proposal to 
disapprove the SIP was decidedly not based on the supposed use of a 
source category-based analysis by Texas. Therefore, these comments have 
not accurately described the proposed basis of disapproval. We 
understand many of these comments arose because our proposal included a 
statement that ``individual sources were not considered by the TCEQ.'' 
This statement was not offered to propose a basis for disapproval, but 
we understand it is susceptible to being taken out of context 
(particularly in consideration of the comments received). It is perhaps 
more plain to state that individual sources were not effectively 
considered by the TCEQ. As our proposal and the Texas SIP itself make 
clear, Texas did, in fact, partially evaluate controls for certain 
individual sources. In evaluating these controls, Texas employed a 
large, superficially refined control set consisting of a mix of large 
and small sources from a number of different source categories located 
within varying distances of Class I areas. It did assess individual 
source data for some factors such that we do not necessarily agree with 
commenters who brand it a ``source category analysis.''
    Whatever its label, we proposed to disapprove Texas' reasonable 
progress analysis because it was flawed in several specific ways. A 
primary flaw was that the control set was over-inclusive. It included 
controls on sources that served to increase the total cost with little 
visibility benefit. As was

[[Page 314]]

noted in our proposal,\78\ Texas adopted this approach despite evidence 
in the record of identified source-specific, cost-effective controls 
that would have resulted in large emission reductions on certain EGUs, 
and despite source apportionment modeling that identified large impacts 
from EGU sources in northeast Texas. Our proposal explained that this 
approach obscured benefits that might be obtained from individual 
sources and only considered aggregated costs. As we also explained, the 
submitted analysis failed to study or consider scrubber upgrade 
candidates. It was accordingly under-inclusive of large, highly cost-
effective emissions reductions that would lead to significant 
improvements in visibility. These points are validated by the technical 
record for this FIP.
---------------------------------------------------------------------------

    \78\ 79 FR 74838 (``[W]e believe that individual benefits were 
masked by the inclusion of those controls with little visibility 
benefit that only served to increase the total cost figures.'')
---------------------------------------------------------------------------

    Therefore, whether the state's analysis is labelled a source 
category analysis, an analysis of multiple individual sources, or some 
hybrid, we conclude that it contained serious deficiencies that would 
materially affect the outcome of the state's SIP process. As a result, 
we conclude this component of the SIP requires disapproval.
    Finally, it bears noting that the approach we have taken in our FIP 
to identifying appropriate controls does not dictate the approach that 
Texas or any other state must take to assess controls. Given Texas' 
size and the range of distances from point sources to Class I areas, 
the mix of controls at EGUs and other large point sources in the state, 
and the overall significance of the impacts from these point sources, 
we considered it appropriate to undertake a source specific analysis to 
avoid the potential for over-controlling sources.\79\ In some 
circumstances, depending on the types of sources at issue, the impacts 
from these sources relative to other causes of visibility impairment, 
the types of controls under consideration, and other such factors, a 
source category approach can be appropriate. Ultimately, however, while 
there is flexibility in available analytical approaches, states cannot 
adopt an approach to reasonable progress, which by its nature overlooks 
cost-effective controls that would otherwise be viewed as being 
beneficial.
---------------------------------------------------------------------------

    \79\ On this point, it also bears noting that Texas' EGUs 
operate within a state that is at least three times larger than 38 
of the states and a full 60% larger than California, the next 
largest of the contiguous states.
---------------------------------------------------------------------------

    Comment: Because of guidance and precedent that ``source category'' 
analyses can be appropriate, individual sources or point sources cannot 
be subject to source-specific controls to meet reasonable progress. 
Individual sources can be subject to control for purposes of addressing 
BART or RAVI requirements but additional, source-specific controls may 
not lawfully be imposed.
    Response: We disagree with the argument that, because a source 
category analysis may be appropriate in some circumstances, sources 
cannot be subject to source-specific controls to ensure reasonable 
progress toward improving visibility. It is unclear how a state would 
develop a SIP containing ``emission limits, schedules of compliance, 
and other measures may be necessary to make reasonable progress,'' as 
required by CAA section 169(A)(b)(2), without the option of source-
specific controls going forward. There is nothing in the visibility 
provisions of the CAA or the Regional Haze Rule suggesting otherwise.
    Comment: Information on FGD scrubber upgrades cannot be used to 
disapprove the SIP because that information was acquired through EPA's 
authority to obtain information under CAA section 114, but the state 
has no equivalent corresponding authority. EPA comment letters and 
communications in past years had not informed the state of the 
importance of analyzing scrubber upgrades.
    Response: Neither of these observations would justify our approving 
a flawed component of a SIP revision--in this case an analysis within 
that SIP revision--that, among other things, had unreasonably 
overlooked the option of FGD upgrades. Our 2005 BART rule discussed the 
state evaluation of scrubber upgrades in several places.\80\ The 
technical information in our proposal validates FGD upgrades as an 
option that should have been considered, and we consider this technical 
record to have been reinforced and further validated with additional 
information and comments provided in support of the proposal. Even as 
we acknowledge that the TCEQ does not have authority (or any present 
delegation of authority) to request information under CAA section 114, 
this is not any kind of determinative limitation on the state's 
technical and regulatory capacities and tools for producing and 
developing information on an air pollution control measure such as FGD 
upgrades. Texas has engaged in air quality control planning and air 
pollution prevention under the CAA for decades, and the Texas agency or 
agencies responsible for SIP adoption and implementation are required 
to possess the necessary legal authority under state law to adopt and 
implement all SIP measures.\81\ Consequently, in this case, the TCEQ 
bore the responsibility of developing or requesting information needed 
to properly assess scrubber upgrades. Lastly, as we state above, any 
past EPA comment letters would be intended to be helpful to the 
improvement of any SIP revision that is under development, but they do 
not constitute agency action on that SIP revision or constitute any 
assurance of positive action on that revision upon submission and 
review. Instead and as always, EPA has to formally discharge its 
responsibilities to review any SIP submittal under the provisions of 
CAA section 110(k). Accordingly, the issue of TCEQ's knowledge, notice, 
or lack thereof on FGD scrubber upgrades cannot be resolved in any way 
that would shield the SIP revision from this basis for disapproval.
---------------------------------------------------------------------------

    \80\ See for instance 70 FR 39171: ``You should evaluate 
scrubber upgrade options based on the 5 step BART analysis 
process.''
    \81\ CAA section 110(a)(2)(E); 42 U.S.C. 7410(a)(2)(E) 
(requiring assurances of ``. . . adequate, personnel, funding, and 
authority under State . . . law to carry out'' SIP requirements); 
Section 2.1(c) of appendix V to 40 CFR part 51.
---------------------------------------------------------------------------

G. Constitutional Law

    One commenter cited to the Commerce Clause, Fifth Amendment and 
Constitutional non-delegation principles in support of its contention 
that EPA should not be able to regulate sources under our regional haze 
program. We disagree with these comments. First, under the Commerce 
Clause, the commenter argues that we cannot regulate regional haze on 
the theory that regulated conduct--such as ``carbon emissions'' from 
coal-fired power plants--will have some effect on interstate commerce. 
We disagree with the comment because owners and operators of the Texas 
sources subject to this regional haze FIP are engaged in economic 
activities (the operation of coal-fired power plants) that cause haze-
forming air pollution to travel into other states and substantially 
affect interstate commerce. Each of the Federal Class I areas receives 
substantial numbers of visitors, including those from out-of-state, 
each year. Our regulation of these sources of visibility impairing 
pollution pursuant to the CAA is squarely within the Federal 
government's Commerce Clause authority. Our regulation of emissions 
from coal-fired power plants, which cause and contribute to regional 
haze in multiple states, to fill a gap left by disapproval of a SIP 
seeks to fulfill

[[Page 315]]

the regional haze provisions of the CAA, which in turn are 
constitutional exercises of Congress's power under the Commerce Clause 
of the U.S. Constitution.
    Second, the commenter contends that our Regional Haze Rule suffers 
from a non-delegation problem. We disagree. The CAA's visibility 
provisions provide extensive intelligible principles that guide our 
exercise of discretion. CAA section 169A, as well as other provisions, 
required us to promulgate regulations directing the states to revise 
their SIPs to include emission limits and other measures as necessary 
to make ``reasonable progress.'' \82\ Congress defined reasonable 
progress to be the consideration of four statutory factors, including 
cost and energy impacts.\83\ Congress also directed our regulations to 
require BART for a specific universe of older sources, and again 
provided a set of statutory factors states must consider when 
determining what control technology constitutes BART.\84\ These two 
sets of statutory factors, among several other provisions and 
definitions in CAA section 169A that provide specific instructions to 
EPA and states, clearly constitute intelligible principles under the 
framework set forth in the case cited by the commenter. The Regional 
Haze Rule, which we promulgated pursuant to the statutory mandate in 
CAA section 169A, reflects these same intelligible principles and has 
been upheld by the D.C. Circuit Court.
---------------------------------------------------------------------------

    \82\ 42 U.S.C. 7491(b)(2).
    \83\ Id. at 7491(g)(1).
    \84\ Id. at 7491(b)(2)(A) & (g)(2).
---------------------------------------------------------------------------

    Third, a commenter claims that the EPA has commandeered the states 
in violation of the Fifth Amendment of the Constitution. We disagree 
with this comment. The U.S. Supreme Court has held that, ``the Federal 
Government may not compel the states to implement Federal regulatory 
programs.'' \85\ The CAA in no way compels a state to implement Federal 
regulatory programs. The CAA, instead, authorizes the EPA to promulgate 
and administer a FIP if a state fails to submit an adequate SIP.\86\ 
The EPA will implement the FIP, with no actions required by any part of 
the government of Texas.
---------------------------------------------------------------------------

    \85\ Printz v. United States, 521 U.S. 898, 925 (1997).
    \86\ 42 U.S.C. 7410(c)(1)(A).
---------------------------------------------------------------------------

H. Stay of Effective Date, Consolidated Appropriations Act, and 
Executive Orders 13405 and 13211

    Comment: Any final action should stay the effectiveness and 
effective date of the action or establish a delayed effective date to 
allow for ``judicial vetting'' of EPA's determinations.
    Response: We have reviewed these requests and do not agree that 
taking these measures with our final rule would be appropriate. Our 
final rule initiates the effectiveness of the action to ensure the 
requirements of the CAA are carried into effect. This result is 
consistent with the CAA and with the regulatory rulemaking process more 
generally. We note that CAA section 307(d)(7)(B) allows, in limited 
fashion, for a stay of effectiveness of a rule during any proceeding 
for reconsideration, but this authority presupposes the rule's 
finalization, the rule's effectiveness, and the filing of an 
administrative petition for reconsideration. Making the rule effective 
also ensures the finality of the action ``for purposes of judicial 
review.'' See CAA section 307(b). Nothing in our response here limits 
or inhibits the filing of a petition for judicial review or the powers 
of a reviewing court.
    Comment: EPA should update both its atmospheric modeling platforms 
as part of the upcoming Appendix W rewrite and the cost manual in order 
to support reasonable future assessments of visibility impacts and 
appropriate control strategies consistent with the Committee Report 
associated with the Consolidated Appropriations Act of 2014.
    Response: As a general matter, wherever possible, we intend to 
follow the committee report instructions associated with the 
Consolidated Appropriations Act of 2014, even where not specifically 
incorporated by reference into the CAA itself. We are currently working 
to update our ``Guideline on Air Quality Models'' in appendix W to part 
51 of title 40, Code of Federal Regulations, and we proposed updates on 
July 29, 2015. Also, as of the date of responding to this comment, we 
have proposed updates to chapters within our Control Cost Manual.
    Comment: One commenter stated that if we change the final rule to 
not include SO2 reductions at one of the affected 
facilities, we must conduct an analysis under Executive Order 13045--
Protection of Children from Environmental Health Risks and Safety 
Risks. Another commenter suggested that polluters need to reconsider a 
business model that burdens low income communities, especially those 
with minority populations, with the effects of air pollution, and urged 
that EPA is accountable to low income, underserved, and vulnerable 
communities in Texas that are constantly being ignored.
    Response: As explained more fully in a later section of this 
document and in our RTC document, Executive Order 13045 does not apply. 
To the extent our final rule limits emissions of SO2, this 
will also increase the level of environmental protection and beneficial 
effect on human health for all affected populations without having any 
disproportionately high and adverse human health or environmental 
effects on any population, including any minority or low-income 
population.
    Comment: EPA has improperly avoided analyzing and evaluating 
potential energy-related impacts of the proposed rule on reliability 
and prices of electricity in Texas and the ERCOT region, despite 
Executive Order 13211 requiring such evaluation. The EPA is using a 
loophole in Executive Order 12866, despite meeting the cost and effect 
criteria and the order's purpose, to avoid evaluating the potential 
energy impacts of the proposed action as required by Executive Order 
13211. Moreover, the proposed rule is inconsistent in claiming the rule 
is both of national scope and effect and not of general applicability. 
Additionally, CAA section 169A(g) requires that the state and the 
Administrator consider the energy and non-air quality environmental 
impacts of compliance when determining BART. Finally, citing ERCOT's 
recent report, the proposed FIP affects a significant portion of Texas' 
base load power generation fleet and the potential for adverse effects 
from the EPA's proposed rule is actually increased, not lessened, 
because the costs and impacts of the rule are focused within a smaller 
region. Therefore, regardless of Executive Order 13211 applicability, 
EPA should evaluate and consider the impacts of the proposed FIP on the 
reliability and price of electricity in Texas.
    Response: As explained more fully in a later section of this 
document and our RTC document, Executive Order 13211 does not apply as 
this action is not a rule of general applicability under Executive 
Order 12866. Our determination regarding this is not inconsistent with 
our determination that the rule is of national scope and effect, as 
these are different determinations that we fully evaluated under their 
respective standards, and are not directly comparable. Additionally, we 
did consider the commenter's concerns regarding grid reliability and 
price of electricity, as discussed more fully in the Grid Reliability 
section of this document, so we did not ``utilize a loophole'' in the 
applicability provisions of Executive Order 12866 to

[[Page 316]]

avoid consideration of the concerns raised in this comment.

I. Controls in Addition to CAIR/CSAPR, and CSAPR Better Than BART

    Comment: Texas is the only state included in CSAPR for which EPA is 
issuing a FIP for reasonable progress. EPA proposed to issue a FIP that 
would replace Texas' reliance on CAIR to satisfy the BART requirement 
for EGUs with reliance on CSAPR. But EPA's proposal otherwise 
disregarded CSAPR's more stringent SO2 and NOX 
emission budgets for Texas, as compared to CAIR, as well as the 
additional trading restrictions imposed by CSAPR. For all other states 
that have relied on either CAIR or CSAPR, EPA found such participation 
to satisfy the states' reasonable progress obligation for the first 
planning period for those sources. EPA should not require controls 
beyond BART for BART sources because it is reasonable to conclude that 
no additional emissions controls are necessary for BART sources in the 
first planning period.
    Response: As discussed elsewhere in this document, although we 
proposed to rely on CSAPR to address the BART requirements for EGUs in 
Texas, we are not finalizing that proposed action. On July 28, 2015, 
the D.C. Circuit Court issued its decision in EME Homer City \87\ 
upholding CSAPR but remanding without vacating a number of the Rule's 
state emissions budgets, including Texas' budgets. We are currently in 
the process of determining the appropriate response to the remand, and 
the extent to which the SO2 and NOX CSAPR budgets 
for Texas will change is currently unknown. The uncertainties regarding 
the CSAPR SO2 budgets are particularly relevant given our 
rule's focus on this pollutant.\88\ Even assuming, however, that EME 
Homer City had not invalidated the CSAPR NOX and 
SO2 budgets for Texas and that we were taking final action 
to address the BART requirements through reliance on CSAPR, we do not 
agree that we are prohibited from requiring controls beyond CSAPR for 
purposes of reasonable progress. We noted in 2005 that the 
determination that CAIR provided for greater reasonable progress than 
BART did not answer the question of whether more than CAIR would be 
required in a regional haze SIP.\89\
---------------------------------------------------------------------------

    \87\ EME Homer City Generation v. EPA, 795 F.3d 118 (D.C. Cir. 
2015).
    \88\ ``In short, EPA's 2014 SO2 emissions budgets for 
Texas, Alabama, Georgia, and South Carolina require each of those 
States to reduce emissions by more than the amount necessary to 
achieve attainment in every downwind State to which it is linked. 
The reductions on those four States are unnecessary to downwind 
attainment anywhere. Those emissions budgets are therefore 
invalid.'' EME Homer City, at 129 (citing EME Homer, 134 S. Ct. 
1584, 1608-9 (2014)) (internal quotations omitted).
    \89\ 70 FR 39104, 39143.
---------------------------------------------------------------------------

    Furthermore, such a simplistic comparison ignores the meaningful 
differences between Texas and the other states cited by commenters in 
which no controls on NOX and SO2 from EGUs beyond 
CSAPR were required. As explained in our proposed rulemaking, allowing 
Texas to rely on CSAPR to meet its reasonable progress obligations is 
not appropriate, considering the large impact of Texas sources on 
visibility at Big Bend, the Guadalupe Mountains, and the Wichita 
Mountains and the availability of cost-effective controls even after 
considering CAIR/CSAPR's previously projected reductions.
    Comment: EPA should disapprove Texas' determination to exclude all 
BART-eligible sources from being subject to BART and EPA should do 
source by source BART for NOX. Further, if EPA does not 
finalize the proposed controls for reasonable progress, then EPA should 
do source by source BART for SO2. EPA's proposal to rely on 
CSAPR as an alternative to BART is unlawful for three reasons. First, 
EPA's proposal exempts sources from BART requirements without complying 
with the statutory prerequisites for such an exemption. Second, even if 
EPA could relieve the sources of the obligation to install BART 
controls, the ``Better than BART'' rule upon which EPA relies is 
flawed. Third, the ``Better than BART rule'' is no longer valid given 
the substantial changes in CSAPR allocations and compliance deadlines.
    Response: As discussed above, we are not finalizing our proposed 
action to rely on CSAPR to address BART due to the partial remand of 
CSAPR in EME Homer City. We will address the question of appropriate 
SO2 and NOX BART limits for EGUs in Texas in a 
future rulemaking. Comments concerning the appropriateness of CSAPR as 
an alternative for BART in Texas are not relevant to this action. 
Additionally, we are finalizing the proposed controls for reasonable 
progress. Therefore, the comment that we should do source-by-source 
BART for SO2 if the reasonable progress controls are not 
finalized is moot.

J. Installation of Controls Beyond the First Planning Period

    Several comments assert that our FIP authority is limited to 
``filling the gaps'' in a state's SIP submission. These commenters 
further contend that our FIP authority is limited by the scope of the 
SIP submission. Because the required reasonable progress goals should 
be met at the conclusion of the first planning period, the commenters' 
argument continues, our FIP authority is likewise limited to those 
controls that can be implemented by 2018. We disagree. Our authority to 
use a FIP to address a ``gap'' or ``inadequacy'' in a SIP refers to a 
``gap'' in the plan's coverage of requirements contained in the statute 
and regulations, and is not limited to the specific ``gap'' left by the 
disapproved portions of the scope of action covered in the state's SIP 
submission, as commenters suggest.\90\
---------------------------------------------------------------------------

    \90\ See CAA Sections 110(c) and 303(y).
---------------------------------------------------------------------------

    In this action, we are determining whether Texas has addressed the 
regional haze requirements set forth in the CAA and our implementing 
regulations. Our FIP determines that under a proper assessment of 
reasonable progress factors, additional controls for some sources in 
Texas are warranted for the first planning period. Regulatory delays 
created by a complex Texas submission and EPA actions regarding the 
state's regional haze requirements, including the time needed for EPA 
to assess the complex 2009 submission and the thousands of comments 
received on our proposed action, cannot provide an exemption from the 
CAA requirement to address regional haze. Nor can regulatory delays 
make additional delays excusable when the requisite CAA analysis 
concludes the controls are warranted at the earliest opportunity to 
make reasonable progress. Additionally, there is nothing in the CAA or 
the regional haze rules that constrains our FIP authority to only those 
controls that can be installed in the first planning period. While 
reasonable progress goals reflect that degree of visibility improvement 
attainable during the first planning period (which extends to 2018), as 
was indicated in our proposal, the long-term strategy requirements of 
the program by their very nature look beyond these interim goals to the 
state's ``long term'' approach to addressing regional haze and may 
include control measures and accompanying visibility improvements that 
extend beyond the first planning period.\91\ The commenter's concerns 
center upon controls that are not accounted for in the numerical 
reasonable progress goals, but rather as we acknowledge, are part of 
the long-

[[Page 317]]

term strategy and needed for reasonable progress.
---------------------------------------------------------------------------

    \91\ 79 FR 74874, citing Guidance for Setting Reasonable 
Progress Goals Under the Regional Haze Program, Section 5.2. By 
statute, the long-term strategy for making reasonable progress may 
extend ``ten to fifteen years.'' CAA Section 169A(b)(2)(B); 42 
U.S.C. 7491(b)(2)(B).
---------------------------------------------------------------------------

    Comments also asserted that our proposed FIP disregards the ``time 
necessary for compliance'' factor of the reasonable progress analysis. 
As we discuss in detail in the RTC document, we are required by 
regulation to ``consider'' time necessary for compliance when 
establishing reasonable progress goals, and we satisfied this 
requirement by proposing reasonable progress goals that account only 
for those controls that can be fully installed within the first 
planning period, as is consistent with our Reasonable Progress 
Guidance.\92\ For the scrubber retrofits that may require up to five 
years to fully install, we exercised our authority to propose a long-
term strategy including emission limits that require controls that may 
not be operational during the planning period and therefore are not 
included in the reasonable progress goals. We also note that we expect 
that design and construction of the scrubber retrofits will begin 
within the planning period, in order to meet the five-year compliance 
date. This approach is consistent with other FIPs issued by EPA and 
takes into account the time engagement required to promulgate a FIP 
within a planning period and the significance of the CAA's contemplated 
ten to fifteen year long-term strategy.
---------------------------------------------------------------------------

    \92\ See our Reasonable Progress Guidance, page 5-2: ``It may be 
appropriate for you to use this factor to adjust the RPG to reflect 
the degree of improvement in visibility achievable within the period 
of the first SIP if the time needed for full implementation of a 
control measure (or measures) will extend beyond 2018.''
---------------------------------------------------------------------------

    Other comments asserted that our requirement for controls outside 
of the planning period is inconsistent with previous FIPs. We disagree 
with this comment. First, we have proposed or promulgated FIPs 
requiring controls with compliance dates beyond the first planning 
period, including FIPs for Arkansas and Wyoming. The Oklahoma FIP 
includes requirements beyond the first planning period as the result of 
a stay during litigation. Further, we have applied the requirements of 
the regional haze program to ensure consistency in the requirements 
upon the sources subject to regulation. If we were to follow the 
commenters' arguments and fail to require application of necessary 
controls on Texas sources past the first planning period, those sources 
would be treated inconsistently with sources in other states that were 
required to apply the controls necessary to meet the CAA's requirement 
to address regional haze. We cannot agree to inconsistent application 
of necessary controls at Texas sources due to delays in promulgating a 
FIP or time-intensive installation schedules, but rather, we address 
these program requirements through the long-term strategy, which, as 
discussed above, allows for control strategies that can begin design 
and construction but cannot be completed within the planning period.
    Several comments assert that our regulatory delays preclude EPA 
from imposing certain emission limitations that may not be achieved 
within the first planning period. Despite any delays in finalizing our 
action on the Texas SIP or in promulgating the FIP, we have a duty to 
act on the SIP and a duty to fulfill the regional haze requirements of 
the Act, including the authority to promulgate a FIP that imposes the 
controls required by the CAA where a SIP submission fails to do so. 
This duty and authority is not forfeited or constrained by delays, 
whatever their cause. We likewise disagree with commenters who consider 
it inappropriate for controls to be required after the planning period 
because corresponding visibility benefits may not be realized during 
the planning period. The fact that benefits of such controls may not be 
realized within the first planning period does not affect our 
determination that the controls are necessary nor deprive us of our 
authority to impose the requirements.
    A commenter asserted that all of the controls required under the 
proposed FIP can be installed within the first planning period. We 
agree that in some cases scrubber retrofits can and have been installed 
in less than five years; however, we do not have the information 
necessary to make that determination for each specific facility 
included under the proposed FIP. Thus, we proposed an installation 
timeframe consistent with past successful BART-related scrubber 
retrofits that, while conservative, ensures the necessary time to 
install the controls.

K. Cost

    We received numerous comments related to the cost analyses we 
performed to support the seven scrubber retrofits and the seven 
scrubber upgrades we proposed. These comments were received from both 
industry and environmental groups, and covered all aspects of our cost 
analyses.
    Some of the comments we received from industry concerning our 
proposed scrubber retrofits were objections to our use of the IPM cost 
algorithms that were developed by Sargent and Lundy (S&L) under 
contract to us. As we discuss in our Cost TSD, we programmed the DSI, 
SDA, and wet FGD cost. algorithms, as employed in version 5.13 of our 
IPM model, into spreadsheets.\93\ Industry stated these cost algorithms 
were not accurate enough to warrant their use in individual unit-by-
unit cost analyses and that our use of them violated our Control Cost 
Manual. Others stated the IPM cost algorithms do not consider site-
specific costs, or in the case of wet FGD, do not adequately consider 
wastewater treatment.
---------------------------------------------------------------------------

    \93\ See discussion beginning on page 3 of our Cost TSD for more 
information concerning our use of the IPM cost algorithms.
---------------------------------------------------------------------------

    In summary, we disagree with these commenters and conclude that the 
IPM cost algorithms provide reliable, study-level, unit-specific costs 
for regulatory cost analysis such as required for BACT, BART, and 
reasonable progress.\94\ We received other comments relating to our 
scrubber retrofit cost analyses, but none of them caused us to revise 
our scrubber retrofit cost-effectiveness basis. We also received a 
number of comments that our proposed emission limits were too 
stringent. We disagree with these comments and present several lines of 
evidence, including real-world data demonstrating that our proposed 
emission limits are not only achievable, but are in fact conservative 
in many cases.
---------------------------------------------------------------------------

    \94\ We believe that the IPM cost algorithms provide study level 
accuracy. See pdf page 17 of our Control Cost Manual: ``[a]``study'' 
level estimate [has] a nominal accuracy of  30% percent. 
According to Perry's Chemical Engineer's Handbook, a study estimate 
is `. . . used to estimate the economic feasibility of a project 
before expending significant funds for piloting, marketing, land 
surveys, and acquisition . . . [However] it can be prepared at 
relatively low cost with minimum data.' ''
---------------------------------------------------------------------------

    As we discuss in our proposal,\95\ our scrubber upgrade analyses 
were based on information we received in response to our requests under 
CAA section 114(c). This information was claimed as CBI under 40 CFR 
2.203(b). As a consequence, we are obligated to protect the 
confidentiality of that information while it is subject to such claims, 
which precludes us from publicly posting this in our docket at 
regulations.gov. CBI information, while a part of our rulemaking 
docket, is protected from public disclosure under our CBI requirements. 
Although we received some public domain comments on our proposed 
scrubber upgrades, most were claimed as CBI. We analyzed that 
information, and as we discuss below in our comment response summary, 
we have modified certain aspects of our analyses. Like our proposed 
scrubber upgrade cost analyses, our revised scrubber upgrade cost 
analyses are similarly treated as CBI but are available

[[Page 318]]

for review by the respective facilities. This prevents us from being 
able to publicly disclose the details of our analyses. Our revised 
scrubber upgrade analyses changed our proposed cost-effectiveness basis 
from where all scrubber upgrades were less than $600/ton, to where all 
scrubber upgrades ranged from between $368/ton to $910/ton. This is 
well within a range that we believe is cost-effective, given the 
visibility benefits that will result from the installation of those 
controls.
---------------------------------------------------------------------------

    \95\ See discussion beginning on 79 FR 74876, and section 4.5 of 
our FIP TSD.
---------------------------------------------------------------------------

    Below we present a summary of our responses to the more significant 
comments we received that relate to our proposed cost analyses.
    Comment: We received information from Luminant and NRG claimed as 
CBI concerning our proposed scrubber upgrades. These companies hired 
S&L who alleged that we made various errors in our cost analyses and 
that our proposed SO2 emission rates were too low. In 
related comments, Luminant stated that it hired S&L to review our 
scrubber upgrade cost analyses and, in so doing, it found multiple 
flaws. S&L states that many of our assumptions are not valid, 
especially those regarding the accuracy and scope of the CBI estimates 
we relied upon, our calculation of SO2 baseline emissions, 
achievable efficiency, and our calculations of the operating costs. We 
also received comments from the TCEQ that we should have provided more 
detail about how we developed the costs for these scrubber upgrades. 
Earthjustice \96\ submitted information concerning previous scrubber 
upgrades that supports the reasonableness of our assumed control level 
of 95%.
---------------------------------------------------------------------------

    \96\ When we refer to Earthjustice, we also mean the National 
Parks Conservation Association and the Sierra Club as these groups 
collectively submitted comments. These groups also contracted with 
independent technical experts including Ms. Victoria Stamper, Dr. H. 
Andrew Gray, and Dr. George D. Thurston.
---------------------------------------------------------------------------

    Response: As explained above, because Luminant and NRG claimed the 
above information as CBI, we were required to separate out such CBI and 
respond to it in a separate CBI protected document (organized by 
claimants). Although this information is a part of our record to this 
action, we cannot post it to our electronically posted public docket at 
www.regulations.gov. We disagree with the TCEQ that we should have 
provided more information concerning the cost of the scrubber upgrades 
we analyzed. Our scrubber upgrade cost information was based on 
information supplied under CBI claims by the affected facilities in 
response to requests for information under CAA section 114(a). 
Accordingly, although this information is still in our docket, and is 
being used to support our decision making, it cannot be included in our 
publicly posted docket at www.regulations.gov and can only be disclosed 
by us to the extent permitted by CAA section 114(c) and our regulations 
governing treatment of CBI as set out at 40 CFR part 2, subpart B.
    We generally disagree that our analysis was flawed. We specifically 
used information provided by Luminant's and NRG's own independent 
contractors (e.g. S&L) whom they hired to assist in providing 
information responsive to our CAA section 114 requests. We have 
reviewed the scrubber upgrade cost analyses performed by S&L that were 
provided with separate comments from NRG and Luminant and adopted S&L's 
methodology, which mainly concerned operational costs. However, we 
noted many errors and undocumented cost figures in S&L's analyses. We 
corrected these errors and rejected some of S&L's undocumented 
assertions and/or costs. Nevertheless, in order to produce a 
conservative scrubber upgrade cost analysis and set many of the issues 
that Luminant raises aside, we incorporated many of Luminant's cost 
items. The resulting costs for Luminant's scrubber upgrades increased 
slightly, resulting in a range of $368/ton to $910/ton for all of the 
scrubber upgrades, but remained well within a range that we believe is 
cost-effective, given the visibility benefits that will result from the 
installation of those controls.
    Comment: San Miguel stated that it should not be included in our 
FIP, but if it was included, its SO2 emission limit should 
be increased and its emission averaging period should be changed from a 
monthly basis to an annual basis.
    Response: We have reanalyzed the monthly emission data for San 
Miguel, including calculating the 30 BOD average for it since it 
completed its scrubber upgrades. We reaffirm our proposed conclusion 
that based on the coal that San Miguel has historically burned over the 
last several years, and its demonstrated ability to remove 94% of the 
sulfur from that coal, that it should be able to meet our proposed 
emission limit of 0.60 lbs/MMBtu based on a 30 BOD average. We also 
believe additional spare capacity exists in San Miguel's scrubber 
system. However, similar to what we discussed in our proposal,\97\ and 
in section I.B.3.b, of this action, we offer San Miguel the opportunity 
to install a Continuous Emissions Monitoring System (CEMS) at its 
scrubber inlet and demonstrate that it maintain at least 94% control 
based on a 30 BOD average. Our RTC document has more details on these 
options.
---------------------------------------------------------------------------

    \97\ See discussion beginning on 79 FR 74885.
---------------------------------------------------------------------------

    Comment: The TCEQ summarized its approach to analyzing controls for 
reasonable progress and stated that its approach was adequate. In 
particular, the TCEQ defended its use of a $2,700/ton threshold for 
control, which it stated was used in CAIR, and its decision that the 
cost of the controls was not worth the improvement in visibility.
    Response: As we note in our proposal,\98\ we disagree with the TCEQ 
that its approach to reasonable progress was adequate. We note that to 
the extent that TCEQ's cost threshold was reasonable, our estimate of 
the costs of the controls required by our FIP fall below the $2,700/ton 
threshold used by Texas, with one exception. For the one source with 
estimated costs exceeding $2,700/ton, the costs of controls is less 
than the $2,700 threshold selected by Texas, after adjusting for the 
escalation of costs over time.\99\ The TCEQ's potential control set 
consisted of a mix of large and small sources, located at various 
distances from Class I areas, with a large geographical distribution. 
Some controls would likely result in significant visibility benefits, 
but some would result in little to almost no visibility benefits. 
Because it only estimated the visibility benefit of all the controls 
together and weighed those benefits against the total cost of 
controlling the mix of sources under consideration, the TCEQ was not 
able to assess the benefit of controlling individual sources or the 
subset of sources with significant, and potentially cost-effective, 
visibility benefits. Larger individual benefits were obscured by the 
inclusion of those controls with little visibility benefit that only 
served to increase the total cost figures. As a result, despite its own 
conclusions that controls below $2,700/ton were available for a number 
of sources,\100\ and CENRAP's modeling results that Texas point sources 
impact the visibility at the Wichita Mountains several times more than 
the impacts from Oklahoma's own point sources, Texas ultimately decided 
to not control these sources.

[[Page 319]]

Furthermore, Texas' analysis did not include consideration of scrubber 
upgrades on key sources with large visibility impacts and potentially 
very cost-effective controls. Texas' flawed analysis prevented it from 
properly considering whether reasonable controls were available on the 
subset of sources or group of sources with the largest visibility 
impacts. Although our Regional Haze Rule and our Reasonable Progress 
Guidance provide states with latitude in approaching reasonable 
progress, states must still meet the requirements of the CAA and 
Federal requirements. We conclude that Texas' approach was flawed and 
this fundamental critical flaw in Texas' analyses cannot be approved.
---------------------------------------------------------------------------

    \98\ 79 FR 74838.
    \99\ Conservatively escalating the $2,700/ton value from when it 
was first developed for the CAIR rule, which was finalized on March 
10, 2005, to the time of our analysis, which was conducted in 2014, 
results in a value of $3,322/ton (i.e., the Chemical Engineering 
Plant Cost Index for 2005 = 468.2, and that for 2014 = 576.1; $2,700 
x 576.1/468.2 = $3,322).
    \100\ See Appendix 10-1 of the Texas Regional Haze SIP. For 
example, the costs of scrubbers for Big Brown (Acct No F10020W) 
Units 1 and 2 were determined to be $1,573 and $1,540, respectively.
---------------------------------------------------------------------------

    Comment: Earthjustice agreed with our conclusion that Texas' 
approach to reasonable progress obscured potentially cost-effective 
controls. Earthjustice also generally supported our reasonable 
progress/long-term strategy analysis, concluded that in comparison with 
other actions our costs were conservative (high) but reasonable, but 
stated that additional units should have been proposed for control. 
Earthjustice criticized our emission baseline methodology of 
eliminating the high and low values from the 2009-2013 emission data 
and averaging the resulting three years of data. It reanalyzed our 
scrubber retrofit cost-effectiveness calculations for Big Brown, 
Monticello, Coleto Creek, Welsh Units, W. A. Parish, and Tolk Units 1 
and 2, using a straight 5-year average of the 2009-2013 emissions, and 
concluded our costs were too high. Earthjustice generally stated our 
assumed DSI SO2 removal efficiency was too high. 
Earthjustice believed we should have considered coal blending with low 
sulfur coal and lignite drying. Earthjustice also provided an analysis 
for Novel Integrated Desulfurization (NID). Earthjustice concluded that 
our calculated cost-effectiveness values were too high, and that NID 
was also a viable alternative to SDA and wet FGD and offered some 
advantages.
    Response: We confirm that one of our intentions in performing our 
cost analyses was to conservatively estimate many of the individual 
cost parameters (tending toward a higher cost estimate) and demonstrate 
that even doing this, our proposed scrubber upgrade and scrubber 
retrofit cost analyses were cost-effective. We believe we have met that 
goal. We disagree with Earthjustice that we should have proposed 
additional units for control and respond to this comment in the 
Modeling section of this document and the RTC document. We continue to 
believe our five-year emission baseline methodology, with the 
elimination of the highest and lowest emission years, is appropriate. 
The BART Guidelines, which we drew upon for some of our reasonable 
progress/long-term strategy analyses, state that the emission baseline, 
``should represent a realistic depiction of anticipated annual 
emissions for the source. In general, for the existing sources subject 
to BART, you will estimate the anticipated annual emissions based upon 
actual emissions from a baseline period.''[hairsp]\101\ We eliminated 
the high low values from the 2009-2013 emission to better address 
issues such as variations in coal sulfur content, capacity usage, 
operations, etc., and make the baseline more representative of typical, 
recent plant operations. The difference between our baseline 
calculations and a straight 2009-2013 average is small and would not 
change our conclusion that the scrubber upgrades we proposed are very 
cost-effective. We also believe our DSI analysis strategy was 
appropriate. We analyzed DSI at both a 50% control level that is likely 
achievable for all the units, and the highest level of control the 
units were potentially capable of achieving, with design factors and 
costs adjusted accordingly, thus bracketing the problem.
---------------------------------------------------------------------------

    \101\ 70 FR 39167.
---------------------------------------------------------------------------

    We do not believe there is enough information concerning NID 
installations at this time to warrant an intensive analysis of that 
technology. Given the vendor advertised control efficiency of NID, the 
selection of NID technology rather than wet FGD would not change our 
proposed SO2 limits. With the exception of Tolk, the non-air 
quality environmental impacts of a NID and wet FGD are similar and do 
not warrant eliminating either technology. We proposed that the units 
in question meet certain SO2 emission limits, but we did not 
mandate a specific control technology in doing so. Consequently, any 
unit, including the ones discussed herein, may elect to use a NID to 
achieve our required SO2 emission limits.
    With respect to the comment that we should have considered blending 
the coal used at the units with low sulfur coal, we note that most of 
the units in question either burn lower sulfur Powder River Basin (PRB) 
coal or they blend it with lignite. We do not believe we have the 
necessary technical information (e.g., fuel sulfur content, 
availability, cost, contractual information, etc.) to properly consider 
fuel blending or fuel switching. Nevertheless, the emission reductions 
achieved by switching to cleaner coal are much less than the emission 
reductions anticipated due to the implementation of the required 
controls. We agree that in some circumstances coal drying can be a 
viable technology for improving boiler efficiency and, in the process, 
reduce emissions because less coal is burned to achieve the same heat 
input to the boiler. However, we are not required to consider every 
potential technology under the reasonable progress and long-term 
strategy provisions of the Regional Haze Rule, which applies to the 
analysis in question. We considered both SDA and wet FGD, and the next 
most promising SO2 removal control, DSI. Were we to have 
considered coal drying, it would have ranked below DSI in its ability 
to remove SO2.
    Comment: Luminant provided general objections to our cost analyses 
and stated our analysis relies entirely on a cost-per-ton metric but 
ignores what it considers the more meaningful cost-per-deciview metric.
    Response: Luminant's general cost comments are addressed with 
specificity in the cost section of our RTC document. We reject 
Luminant's contention that we should have used the $/dv metric, a 
contention we also rejected and addressed in our Oklahoma FIP.\102\ We 
note that to use the $/dv metric as the main determining factor would 
most likely require the development of thresholds of acceptable costs 
per deciview of improvement for both single and multiple Class I 
analyses. In Oklahoma v. EPA, the Tenth Circuit Court recognized our 
authority to use a different metric when promulgating a FIP.\103\
---------------------------------------------------------------------------

    \102\ Response to Technical Comments for Sections E. through H. 
of the Federal Register Notice for the Oklahoma Regional Haze and 
Visibility Transport Federal Implementation Plan, Docket No. EPA-
R06-OAR-2010-0190, 12/13/2011, pdf 116.
    \103\ ``When promulgating its own implementation plan, [EPA] did 
not need to use the same metric as Oklahoma. The guidelines merely 
permit the BART-determining authority to use dollar per deciview as 
an optional method of evaluating cost effectiveness.'' Oklahoma v. 
EPA, 723 F.3d 1201, 1221 (10th Cir. 2013).
---------------------------------------------------------------------------

    Comment: S&L cited to capital costs at Monticello 3 and Sandow 4, 
including spray headers and mist eliminators, that we mistakenly 
removed from our scrubber upgrade cost analyses.
    Response: S&L is correct that we did in fact remove these capital 
costs from our scrubber upgrade cost analyses because we noted these 
costs were included in a 2013 Use Determination Application to the 
TCEQ, which identified that new replacement tower spray nozzles and 
mist eliminators had been installed. We wrongly assumed

[[Page 320]]

that after having identified that its scrubber system could be upgraded 
cost-effectively, and having performed some of those modifications, 
Luminant had installed new upgraded spray headers and nozzles rather 
than replacing its worn out spray header and nozzles with the less 
efficient original design. However, based on the comment received on 
this, we added these costs back into our updated scrubber upgrade cost 
analyses and the result was a very minor increase in the cost-
effectiveness value (higher $/ton). This did not affect our conclusion 
that upgrading the scrubbers for these units is very cost-effective.
    Comment: S&L states that in escalating costs, we should have 
assumed its 2006 reports were in 2005 dollars and we should have 
escalated our costs out to 2015. S&L also objected to our use of a 10% 
increase to our escalation to account for escalation outside of the 
customary five-year window, our deletion of Allowance for Funds During 
Construction (AFUDC), and our deletion of owner's costs. S&L, GLCC, and 
CCP allege our use of a 30-year life for our scrubber retrofit and 
scrubber upgrades analyses is inconsistent with our Control Cost 
Manual. Earthjustice supported our 30-year assumed life.
    Response: We agree with S&L that we should have assumed its 2006 
reports were in 2005 dollars, and we have made the appropriate 
correction to our escalation calculations. We disagree that we should 
have carried our escalation costs forward to 2015, because we used the 
most recent emission data that was available, for both the cost 
analyses and modeling, which was 2013 data. As we explain in more 
detail in the Cost section of the RTC document, based on consideration 
of the CEPCI cost indices over the 2005-2013 period, we conclude that 
our approach of adding an additional 10% to our escalated cost is 
reasonable and likely conservative. As we have noted in a number of 
previous actions, AFUDC and owner's costs are not allowable under the 
Control Cost Manual overnight approach.\104\ We refer S&L to our 
response to the scrubber life issue in our Oklahoma FIP in which we 
supported a 30-year life.\105\ Because none of the facilities involved 
have entered into (or offered to enter into) enforceable commitments to 
shut down the applicable units earlier, we have continued to use a 30-
year equipment life for scrubber upgrades, as we believe that is 
proper.
---------------------------------------------------------------------------

    \104\ See for instance our ``Response to Technical Comments for 
Sections E. through H. of the Federal Register Notice for the 
Oklahoma RH and Visibility Transport Federal Implementation Plan,'' 
Docket No. EPA-R06-OAR-2010-0190, 12/13/2011.
    \105\ Response to Technical Comments for Sections E. through H. 
of the Federal Register Notice for the Oklahoma RH and Visibility 
Transport Federal Implementation Plan, Docket No. EPA-R06-OAR-2010-
0190, 12/13/2011. See discussion beginning on page 36.
---------------------------------------------------------------------------

    Comment: Xcel notes that in performing our dry scrubber cost 
analysis for Tolk, we failed to consider that there is a general water 
scarcity in the area with no surface water availability, and that to 
obtain the additional amount of water necessary to support the 
operation of dry scrubbers, Xcel would have to attempt to purchase 
water rights from existing farmers along with a gathering system or 
look at other costly alternatives. Based on the historical cost of 
water rights in the area, this is an additional capital cost of 
approximately $40 million that was not included in EPA's cost 
estimates. Earthjustice encouraged us to investigate Xcel's water 
rights, and estimated the cost to purchase additional water rights 
based on assumptions we used to assess this issue for the Gerald 
Gentleman facility in Nebraska.
    Response: We have conducted an extensive investigation of the issue 
raised in Xcel's comments, including additional communication with Xcel 
and the High Plains Water District, in order to clarify some of Xcel's 
assertions.\106\ We conclude that Xcel's asserted water requirements 
for dry scrubbing are much higher than other similar dry scrubbing 
installations, and the basis for the disparity is unsupported. As 
confirmed by our communications with the High Plains Water District and 
Xcel, we also conclude that Xcel has multiple lines of access to 
adequate supplies of water sufficient to supply the proposed dry 
scrubbers (SDA) without the need to buy additional water rights. First, 
we calculate that water already available at Tolk is almost enough to 
satisfy the additional water demand of our proposed dry scrubbers. 
Second, we note that Xcel receives blowdown water from nearby Plant X 
\107\ and that Xcel offered testimony to the Public Utility Commission 
of Texas that two units in Plant X will retire in 2019 and 2020, which 
will free up additional water that could be used to satisfy the 
additional water demand of our proposed dry scrubbers. Third, we 
believe that Xcel has access to additional unexploited water rights 
that are more than adequate to supply our proposed dry scrubbers. 
Lastly, we acknowledge that Tolk's ultimate sources of water, the 
Ogallala Aquifer, continues to be depleted. However, considering the 
water needed by our proposed dry scrubbers is by Xcel's own account 
only approximately 9 to 12% of the total plant's needs, the aquifer's 
depletion will be a limiting factor on the operation of the plant 
itself, not on the operation of the scrubbers.
---------------------------------------------------------------------------

    \106\ Please see our docket for inclusion of this communication, 
which are in the form of emails transmitting letters and other 
information.
    \107\ ``Plant X'' is the actual name of a nearby EGU also owned 
by Xcel.
---------------------------------------------------------------------------

    Comment: Xcel alleged that in our cost analysis we failed to 
consider that our proposed dry scrubbers would (1) end Tolk's sales of 
its fly ash or require the installation of additional baghouse 
capacity, and (2) require additional landfill capacity. Xcel also 
alleged that we did not adequately consider DSI and non-air 
environmental impacts, and that our assumption of a 30-year operating 
life is wrong.
    Response: We disagree with these comments. Our cost analysis did 
include an additional baghouse that could be installed upstream of the 
dry scrubber which can preserve Tolk's existing fly ash sales. Also, 
our cost analysis included landfill costs, which based on Xcel's own 
information, are adequate to cover the additional disposal costs. We 
also believe our DSI cost methodology, in which we bounded the range of 
expected DSI performance, was adequate and demonstrated that DSI was 
not cost-effective when compared to the dry scrubber we costed for 
Tolk. Lastly, as we discuss in our responses to other comments, we 
believe our assumption of a 30-year life is proper, and we note that in 
testimony to the Public Utility Commission of Texas (PUCT), Tolk 
assumed similar equipment lives.
    Comment: S&L states we overestimated SO2 reductions (and 
thus our cost-effectiveness calculation was too low) for scrubber 
upgrades due to our SO2 baseline methodology in which we 
eliminated the high and low annual average values from 2009-2013 and 
averaged the remaining three yearly values. Earthjustice stated we 
overestimated our cost-effectiveness calculations for our scrubber 
retrofits in part due to our SO2 baseline methodology. 
Earthjustice stated it would have been more appropriate to use a five-
year annual average emissions baseline, five-year annual average 
SO2 rate in lb/MMBtu, and five-year average gross heat rate 
and MW-hrs generated, based on data from 2009 to 2013.
    Response: We disagree with the commenters. As we note in our 
proposal, we used the BART Guidelines for some aspects of our analysis 
and believe our methodology is in agreement

[[Page 321]]

with the relevant language in that regard.\108\ We calculated our 
baseline SO2 emissions by first acquiring the 2009 to 2013 
emissions as reported to us by the facilities in question. This is 
reflective of the actual emissions from the underperforming scrubber 
systems installed at the units in question. We then calculated the 
uncontrolled SO2 emissions by acquiring U.S. Energy 
Information Agency coal usage data. We used these two figures to 
calculate the level of control for each year. In so doing, we 
eliminated the highest and lowest annual emission values from 2009-2013 
to better address the issues S&L raises in its other comments 
(variations in coal sulfur content, capacity usage, operations, etc.) 
and to make the baseline more representative of typical, recent plant 
operations. The difference between our baseline calculations and a 
straight 2009-2013 average is small and does not change our proposed 
conclusion that the scrubber upgrades we proposed are very cost-
effective.
---------------------------------------------------------------------------

    \108\ 70 FR 39167. ``The baseline emissions rate should 
represent a realistic depiction of anticipated annual emissions for 
the source.'' See also 79 FR 74874.
---------------------------------------------------------------------------

    Comment: S&L stated that our assumption that wet FGD retrofits can 
achieve 98% reduction or a controlled SO2 emission rate of 
0.04 lb/MMBtu is unrealistic and cannot be sustained on a continuous, 
long-term basis. Earthjustice stated that our assumed scrubber retrofit 
emission rates were not stringent enough.
    Response: We disagree with S&L. First, we note that vendors 
routinely guarantee SO2 emission limits at least as 
stringent as, or more stringent than, what we have proposed. We have 
also conducted extensive analysis of a number of SO2 
scrubber retrofits in which we have plotted their 30 BOD SO2 
emission limits.\109\ Of the units we analyzed, 13 retrofit units have 
guaranteed control efficiencies of 95% to 99%, with eight of them 
guaranteed at 98% to 99%. With one exception, these eight units are 
achieving 98% to 99% SO2 control, when calculated using a 
very conservative method we have adopted. We also demonstrate that 
units similar to the ones in question are able to continuously sustain 
SO2 limits lower than what we have proposed for at least one 
year, and in some cases much longer. For instance, three of the units 
have achieved a maximum 30-day BOD equal to or less than our proposed 
SO2 emission limit for scrubber retrofits of 0.04 lb/MMBtu:

    \109\ See our RTC document for much more detail on our analysis, 
and the file, ``Selected scrubber retrofit efficiencies.xlsx,'' 
which is in our docket and contains the plots discussed. The 
performance of each scrubber in our data set is summarized in the 
file, ``Selected scrubber retrofit efficiencies.xlsx.''
---------------------------------------------------------------------------

 Scherer Unit 2: 0.01 lb/MMBtu based on 485 data points \110\
---------------------------------------------------------------------------

    \110\ Where ``data point'' represents a valid daily 
SO2 monitored value.
---------------------------------------------------------------------------

 Iatan Unit 1: 0.02 lb/MMBtu based on 2,004 data points
 Boswell Energy Center: 0.03 lb/MMBtu based on 1,881 data 
points

Our technical conclusions are also consistent with past judicial 
findings regarding achievable removal efficiencies and control rates, 
including conclusions in the already five years past case of United 
States v. Cinergy Corp., 618 F. Supp. 2d 942, 947 and 961-962 (S.D. 
Ind. 2009).\111\ Thus, we disagree with S&L that our proposed scrubber 
retrofit SO2 emission limits are not realistic or 
maintainable on a long-term basis. We agree with Earthjustice that it 
may be possible that many of the scrubber retrofit units can achieve 
greater control efficiencies than we proposed. Greater control 
efficiencies would result in a more favorable cost-effectiveness (lower 
$/ton) and more visibility improvement. This is another area in which 
we strove to be conservative in our analyses in order to demonstrate 
that even with many conservative cost assumptions the scrubber 
retrofits we proposed are cost-effective.
---------------------------------------------------------------------------

    \111\ While the underlying expert report submitted by the 
Department of Justice in that case is protected from release under 
Court order, the testimony of the government expert witness that 
substantially accords with it, as well as our conclusions in 
responding to this comment, has been added to our docket.
---------------------------------------------------------------------------

    Comment: S&L stated that our use of the IPM cost algorithms was not 
in keeping with our Control Cost Manual and because of the limited 
number of site-specific inputs, the IPM cost algorithms provide order-
of-magnitude control system cost estimates, but do not provide case-by-
case project-specific cost estimates meeting the requirements of the 
BART Guidelines, nor do the IPM equations incorporate the cost 
estimating methodology described in the Control Cost Manual.
    Response: We disagree with S&L. As we stated in our Cost TSD, we 
relied on the methods and principles contained within the Control Cost 
Manual, namely the use of the overnight costing method. In fact, the 
Control Cost Manual does not include any method for estimating the 
costs of any of the SO2 control methods evaluated in this 
action. We note our strategy of relying on a publicly available control 
cost tool is similar to the strategy the states themselves employed in 
the development of their own SIPs. For instance, as explained in the 
Texas SIP, the TCEQ used the control strategy analysis completed by the 
CENRAP, which depended on the EPA AirControlNET tool \112\ to develop 
cost per ton estimates. We have used IPM cost models to estimate BART 
costs in other similar rulemakings including our Arizona regional haze 
FIPs,\113\ the Wyoming regional haze FIP,\114\ and to supplement our 
analysis in the Oklahoma FIP.\115\ S&L used real world cost data to 
construct its cost algorithms and confirm their validity. These cost 
models have been updated and maintained since their introduction in 
2010 and have been continuously used by us since that time. These 
control costs are based on databases of actual control project costs 
and account for project specifics such as unit size, coal type, gross 
heat rate, and retrofit factor, and they require unit specific inputs 
such as reagent cost, waste disposal cost, auxiliary power cost, labor 
cost, gross load, and emission information. We believe that the IPM 
cost models provide reliable study-level, unit-specific costs for 
regulatory cost analysis such as required for BACT, BART, and 
reasonable progress. Lastly, we are confident in the basic methodology 
behind the S&L cost algorithms such that in our recent proposal for 
updating the SCR chapter of the Control Cost Manual,\116\ we presented 
an example costing methodology that is based on the IPM S&L SCR 
algorithms, which were developed using a similar methodology to the wet 
FGD, SDA, and DSI cost algorithms discussed herein.
---------------------------------------------------------------------------

    \112\ Our AirControlNET tool is out of date and no longer 
supported.
    \113\ 77 FR 42852 (July 20, 2012).
    \114\ Memorandum from Jim Staudt to Doug Grano, EPA, ``Review of 
Estimated Compliance Costs for Wyoming Electricity Generating Units 
(EGUs)--revision of previous memo'', February 7, 2013, EPA-R08-OAR-
2012-0026-0086.
    \115\ 76 FR 81728 (December 28, 2011).
    \116\ 80 FR 33515.
---------------------------------------------------------------------------

    Comment: S&L stated that the IPM cost algorithms do not adequately 
consider site specific information and it cites to a number of 
possibilities including demolition and relocation of equipment, 
modifications that may be required to the existing ash handling 
systems, replacement of the existing induced draft fans or booster fan 
modifications, modifications/upgrades to the existing auxiliary power 
system, and labor productivity. S&L criticized our use of a retrofit 
factor of 1.0 for all units, and stated that the inlet temperature of 
Big Brown and Monticello units was 360-370 F, which

[[Page 322]]

is above the 300 F assumed value in the IPM algorithms, and would 
result in a flue gas volume increase of 10%, requiring additional 
costs.
    Response: We note that the IPM cost algorithms, which are derived 
from real world costs, already have retrofit issues built into them. 
Our assumption of a retrofit factor of 1.0, which represents an average 
retrofit difficulty, likely overestimates the costs of some facilities 
(e.g., Tolk) that have no retrofit issues. We solicited comments on all 
aspects of our scrubber retrofit cost analyses, but received little of 
the site-specific information to which S&L cites. Also, S&L provides no 
documentation for those it does cite. Regardless, these types of issues 
result in small increases in costs that are well within the required +/
-30% accuracy \117\ and do not affect cost-effectiveness conclusions 
due to the conservative nature of our estimates, as demonstrated 
elsewhere in these responses.
---------------------------------------------------------------------------

    \117\ Control Cost Manual, p. 2-3.
---------------------------------------------------------------------------

    S&L does not provide any documentation to support its contention 
that the IPM wet FGD cost algorithms are based on a generic scrubber 
inlet temperature of 300 F. We have researched all available references 
on this issue and cannot find anything to support this conclusion. 
Rather, we conclude that the IPM cost algorithms estimate costs from 
regression equations based on actual completed projects. There are a 
number of factors other than temperature that affect the volume of gas 
flow that passes through a scrubber system. These include the amount of 
in-leakage in the system (which often increases due to inefficient or 
worn seals in the air preheater) and the type and characteristics of 
the coal that is being burned. This is made clear by examination of two 
of the scrubber retrofit reports for Big Brown (one of the units S&L 
cites), which were issued by S&L in 2004 and 2007, we received in 
response to our CAA Section 114 requests.\118\ The 2004 report 
indicated that the design flue gas flow rate at the scrubber inlet was 
approximately 19.7% less than that in the 2007 report. However, both 
reports indicated that the reference temperature at the inlet was 370 
[deg]F--the same temperature S&L references in its comment--and both 
were at the same pressure. It is clear there are many variables that 
impact flow beyond temperature. We therefore conclude that S&L has not 
documented its temperature assertion, available information does not 
support it, and its temperature inference is too simple to properly 
characterize the situation. In any case, even assuming a 10% increase 
in gas flow rate, would not result in a significant enough increase in 
cost to impact our decision regarding these facilities.
---------------------------------------------------------------------------

    \118\ LUMINANT_000277496.pdf and LUMINANT_REGHAZ_1-000001183 to 
-000001257.pdf.
---------------------------------------------------------------------------

    Comment: S&L states the IPM cost module includes costs only for 
minor physical and chemical wastewater treatment. However, wastewater 
treatment standards proposed by EPA, and anticipated to be published as 
a final rule in 2015, will likely require significantly more advanced 
treatment of FGD wastewaters. S&L states this could add $30-$40 million 
to the cost of a retrofit wet FGD control system and we should have 
included these costs in our estimates.
    Response: Because our wastewater treatment rules have not been 
finalized, and therefore we do not know with certainty whether any 
additional costs may be incurred, it is not appropriate for us to 
include those costs in our cost-effectiveness calculations. Even if 
those costs prove to be substantial, other options are available, 
including zero liquid discharge systems and the selection of a 
SO2 control technology that achieves the emission limit 
without generating a wastewater stream, such as NID scrubbers, which we 
believe are capable of achieving our emission limits, and have been 
selected in some recent installations.\119\ In addition, we believe 
that at least one of the studies that produced actual costs that were 
used to construct the IPM cost algorithms included wastewater treatment 
costs. Lastly, we did not receive any documentation from any facility 
to substantiate any wastewater treatment costs, including the figures 
that S&L cites.
---------------------------------------------------------------------------

    \119\ We recently proposed approval of NID as BART for the Flint 
Creek Unit 1 in Arkansas (80 FR 18944). Other recent installations 
include the Homer City Units 1 and 2, Boswell Unit 4, Brayton Point 
Unit 3, and Indian River Unit 4.
---------------------------------------------------------------------------

    Comment: Luminant and others allege we did not properly balance 
costs and visibility benefit and stated we should have used the dollar 
per deciview ($/dv) metric.
    Response: We disagree that the $/dv metric is more meaningful than 
our use of the $/ton metric in conjunction with our consideration of 
the visibility benefit from the installation of controls. As we noted 
in our Oklahoma FIP,\120\ use of the $/dv metric would most likely 
require the development of thresholds of acceptable costs per deciview 
of improvement for BART determinations for both single and multiple 
Class I analyses, and we have not developed such thresholds. This 
decision by EPA not to use this metric in a FIP was reviewed and upheld 
in Oklahoma v. EPA by the Tenth Circuit Court.\121\ We see no reason to 
deviate from our view of the dollar per deciview metric in the 
reasonable progress context that applies here. We also note that the 
use of the dollar per deciview metric is further complicated in the 
present case due to our use of CAMx modeling. As we discuss in our 
proposal and elsewhere in the Modeling section of this document and in 
Modeling Sections of our RTC document, there is no way to directly 
compare the CAMx modeling we used in our proposed Texas/Oklahoma FIPs 
with previous CALPUFF modeling results because of differences in the 
models, model inputs, and metrics used.\122\
---------------------------------------------------------------------------

    \120\ Response to Technical Comments for Sections E. through H. 
of the Federal Register Notice for the Oklahoma Regional Haze and 
Visibility Transport Federal Implementation Plan, Docket No. EPA-
R06-OAR-2010-0190, 12/13/2011, pdf 116.
    \121\ Oklahoma v. EPA, 723 F.3d 1201, 1221 (10th Cir. 2013).
    \122\ See our FIP TSD, page A-35 and modeling section of the RTC 
document.
---------------------------------------------------------------------------

L. Cost Versus Visibility Benefit

    Comment: Our proposed controls would not result in perceptible 
visibility improvements and thus should not be finalized. Commenters 
also stated that the required controls result in miniscule or 
insignificant visibility improvements.
    Response: We disagree that the Regional Haze Rule requires that 
controls on a source or group of sources result in perceptible 
visibility improvement.\123\ As we noted in our TSDs, we derived much 
of our approach to the analysis of control costs and visibility impacts 
from the BART Guidelines.\124\ In a situation where the installation of 
BART may not result in a perceptible improvement in visibility, the 
visibility benefit may still be significant, as explained by the 
Regional Haze Rule: \125\
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    \123\ It is generally recognized that a change in visibility of 
1.0 deciview is humanly perceptible.
    \124\ See the discussion in our FIP TSD, beginning on page 6.
    \125\ 70 FR 39129.

    Even though the visibility improvement from an individual source 
may not be perceptible, it should still be considered in setting 
BART because the contribution to haze may be significant relative to 
---------------------------------------------------------------------------
other source contributions in the Class I area.

We accordingly disagree that selection of control measures should be 
contingent upon perceptible visibility improvement. As we stated in our 
previous rulemaking addressing the BART determinations in Oklahoma: 
\126\
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    \126\ 76 FR 81739.


[[Page 323]]


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    Given that sources are subject to BART based on a contribution 
threshold of no greater than 0.5 deciviews, it would be inconsistent 
to automatically rule out additional controls where the improvement 
in visibility may be less than 1.0 deciview or even 0.5 deciviews. A 
perceptible visibility improvement is not a requirement of the BART 
determination because visibility improvements that are not 
perceptible may still be determined to be significant.
    Thus, in our visibility improvement analysis, we have not 
considered perceptibility as a threshold criterion for considering 
improvements in visibility to be meaningful. Rather, we have considered 
visibility improvement in a holistic manner, taking into account all 
reasonably anticipated improvements in visibility and the fact that, in 
the aggregate, improvements from controls on multiple sources will 
contribute to progress towards the goal of natural visibility 
conditions. Visibility impacts below the thresholds of perceptibility 
cannot be ignored because regional haze is produced by a multitude of 
sources and activities which are located across a broad geographic 
area. In this action, as discussed below, we found that the required 
cost-effective controls reduce visibility impairment from those sources 
with the largest visibility impacts and result in meaningful visibility 
benefits towards the goal of natural visibility conditions.
    As we have noted and discussed in a separate response to comment, 
the results of the CAMx modeling we have utilized in our proposal 
cannot be directly compared to the results of CALPUFF modeling, which 
has been utilized in the vast majority of other BART and reasonable 
progress/long-term strategy actions, because of differences in the 
models, model inputs, and metrics used.\127\ Many of these differences 
result in CAMx modeled visibility impacts and benefits that are much 
lower than the CALPUFF modeled visibility impacts and benefits relied 
on in other actions. We disagree with commenters that the visibility 
benefits from the controls in our FIP are miniscule when the 
differences in modeling analyses are considered. We observe that 
several comments that are critical of the extent of the visibility 
benefits have cited only to benefits from the scrubber upgrades, 
omitting the total anticipated visibility benefit from all required 
controls. As we discuss in the FIP TSD and in separate responses to 
comments, we believe it is necessary to consider visibility benefits 
based on ``clean'' natural background conditions to assess the full 
potential for visibility benefits from controls. For example, we 
estimated that the required controls provide for over 3 dv improvement 
on 20% worst days at the Wichita Mountains when estimated using a 
``clean'' background and result in improving projected visibility 
conditions by 0.45 dv over the visibility conditions projected by 
CENRAP and Texas for 2018 and an estimated 0.62 dv improvement in the 
visibility conditions in 2018 when considering recent actual emissions 
(values are for 20% worst days). The required controls result in a 
greater than 5% improvement in overall visibility conditions at the 
Wichita Mountains on the 20% worst days. We also estimate that the 
required controls significantly reduce the projected delay in meeting 
natural visibility, helping to achieve that goal 25 to 30-years earlier 
at Big Bend and the Guadalupe Mountain by our projections.
---------------------------------------------------------------------------

    \127\ FIP TSD at A-35.
---------------------------------------------------------------------------

    The CENRAP modeling showed that Texas sources have significant 
visibility impacts at the Wichita Mountains and the Texas Class I 
areas. Our analysis identified those point sources with the greatest 
contributions to visibility impairment at these Class I areas, and the 
required controls reduce visibility impairment from those sources with 
the largest impacts where controls were determined to be available and 
reasonable for this first planning period. For example, the Monticello 
and Big Brown facilities are projected to contribute approximately 1.3 
Mm-\1\ and 1.2 Mm-\1\, respectively, to 
visibility impairment on the 20% worst days at the Wichita Mountains in 
2018 based on the CENRAP 2018 projected emissions for these 
facilities.\128\ This is 1.7% and 1.5% of the total visibility 
impairment at the Wichita Mountains.\129\ In our FIP TSD we noted that 
Texas used an impact extinction level threshold of 0.5 
Mm-\1\ (a level less than half of the estimated impact from 
the Monticello or Big Brown facilities) from all sources in a state as 
a threshold for inviting another state to consult. Oklahoma selected a 
threshold of 1.0 Mm-\1\ to determine which states should 
consult in analyzing visibility impairment at the Wichita 
Mountains.\130\ We also noted that the largest projected contribution 
from all point sources within a state at the Wichita Mountains after 
Texas (14%) is Oklahoma at 3.9%. In other words, elimination of all 
point sources in Oklahoma would result in less visibility benefit 
(3.9%) than the required controls (greater than 5%). As these facts 
demonstrate, the identified facilities have significant impacts on 
visibility conditions. Our technical record makes it equally plain that 
the required controls reduce impacts from these sources and result in 
meaningful visibility benefits towards the goal of natural visibility 
conditions.
---------------------------------------------------------------------------

    \128\ Light extinction, in units of inverse megameters 
(Mm-\1\), is the amount of light lost as it travels over 
one million meters. The haze index, in units of deciviews (dv), is 
calculated directly from the total light extinction, bext, as 
follows: HI = 10 ln(bext/10).
    \129\ We note that the impacts from Big Brown and other 
facilities are even larger when considering recent actual emissions 
rather than the CENRAP 2018 projected emissions.
    \130\ See Texas Regional Haze SIP Appendix 4-1: Summary of 
Consultation Calls and Section X.A. of the Oklahoma Regional Haze 
SIP.
---------------------------------------------------------------------------

    Comment: Texas' choice of 0.5 deciview as a benchmark for total 
visibility improvement (from all sources) to use in its four-factor 
analysis was reasonable and consistent with EPA guidelines. Under the 
BART Guidelines, a source ``contributes to any visibility impairment,'' 
and thus becomes subject to BART, if it has an impact greater than 0.5 
deciview at any Class I area. It is thus logical that a level of 
visibility improvement at a single Class I area that is less than the 
threshold at which a source becomes subject to BART in the first place 
would be deemed insignificant for all sources. Indeed, in other 
regional haze actions, EPA has ``defer[red]'' to states' consideration 
of the 0.5 deciview threshold. And given Congress's special emphasis on 
BART sources, Texas' reference to the BART 0.5 deciview threshold to 
evaluate reasonable progress for the first planning period was 
conservative, and Texas could reasonably determine that total 
visibility benefits below the BART threshold for an individual source 
should be deferred until a later planning period for reasonable 
progress.
    Response: We disagree that Texas' choice of a 0.5 dv visibility 
threshold, including the manner in which it was applied, was proper in 
its analysis. First, the quote from our BART Guidelines was based on 
CALPUFF modeling and not CAMx modeling. Texas extrapolated results from 
CAMx modeling to estimate the visibility improvement due to all the 
identified controls in their analysis and then compared it to a 
threshold developed for CALPUFF modeling. As we state in the FIP TSD 
and discuss in detail in our response to comments, ``[a] common metric 
used in BART visibility modeling using CALPUFF is the BART screening 
level of 0.5 del-dv used by most states for screening out facilities 
from further BART consideration. However, there are a number of factors 
that make the two analyses different and not comparable, invalidating 
the use of the BART screening metric, or other such comparisons with 
modeled visibility impacts for reasonable progress with

[[Page 324]]

CAMx or CMAQ.'' \131\ In the FIP TSD and in separate responses to 
comments we discuss the differences in the models, model inputs, and 
metrics used. Many of these differences contribute to CAMx modeled 
visibility impacts and benefits for reasonable progress being much 
lower than the CALPUFF modeled visibility impacts and benefits for BART 
relied on in other actions. As detailed in the FIP TSD, these 
differences include the emission rates modeled, the metrics used and 
whether the deciview impacts are calculated based on ``clean'' natural 
background conditions or a ``dirty'' background based on degraded 
visibility conditions projected for 2018. The CALPUFF emissions modeled 
for BART are representative of maximum emission rates and are therefore 
usually significantly larger (often in the range of double) than 
average emission rates used in CAMx modeling for a reasonable progress 
analysis. One of the main metric differences is that the CALPUFF 
analysis for BART utilizes a clean background and compares the 8th 
highest daily maximum impact from the specific source modeled to 
compare against a 0.5 dv threshold to indicate significant impacts 
while the visibility benefit that was estimated by Texas to assess the 
benefit of additional controls for reasonable progress was based on a 
``dirty'' or degraded background and average benefits over the 20% 
worst days observed by the monitor at the Class I area which may or may 
not be inclusive of the highest impact days from the specific source 
modeled with CALPUFF for BART. As we discuss in detail in the FIP TSD, 
because the deciview metric is a logarithmic function of extinction, 
visibility impacts and improvement calculated based on ``dirty'' 
conditions are substantially lower than those calculated based on 
natural ``clean'' conditions.\132\ These differences were not 
considered in Texas' visibility analysis and selection of threshold. We 
note that Texas did calculate visibility impacts compared to natural 
visibility conditions and focused on the maximum impact from the 
modeled sources in their BART visibility analysis, which also relied on 
CAMx photochemical modeling, to determine the significance of 
visibility impacts from BART sources for BART screening purposes. 
However, in assessing the benefit of additional controls for reasonable 
progress, Texas only considered visibility benefits averaged over the 
20% worst days based on a ``dirty'' or degraded background.
---------------------------------------------------------------------------

    \131\ FIP TSD at A-35 and modeling section of the RTC document.
    \132\ FIP TSD at A-38. ``For example, see Figure A.3-5 which 
shows the del-dv change due to a 10 (1/Mm) change at both the 2018 
projected extinction level [``dirty background''] and the 2064 
natural visibility conditions [``clean background''] extinction 
level for the Wichita Mountains. In the `dirty background' case the 
10 (1/Mm) yields a 1.26 del-dv, whereas in the `clean background' 
case the same 10 (1/Mm) yields a 3.86 del-dv improvement. In this 
example, the `clean background' situation yields a del-dv 
improvement 3 times greater than the `dirty background' for the same 
level of extinction improvement.
---------------------------------------------------------------------------

    The difference between comparing visibility improvement on a 
``clean'' and ``dirty'' background is analogous to comparing the change 
in sound volume that would occur if one person stopped singing loudly 
in an empty room (clean background) to the change that would occur if 
one person stops singing loudly in a room crowded with a 100 people 
singing loudly (dirty background). In both cases, to return the room to 
natural background sound level, the individual singers must be 
addressed, but there will be little or no perceptible difference in 
volume when one singer in the crowded room stops singing. To carry the 
analogy further, our analysis was designed to identify the Texas 
sources with the greatest visibility impact (the loudest singers) and 
address them in this first planning period.
    Second, the 0.5 dv threshold in the context of BART is used to 
assess the maximum total visibility impact from all BART units at a 
facility. If the impact from all the BART sources at a facility is 
above the threshold, then each BART unit must be evaluated for 
controls, and therefore the visibility improvement anticipated from 
controls would be less than 0.5 dv on a facility basis, and much less 
than 0.5 dv on a unit specific basis for BART sources with multiple 
BART units. For these reasons, the BART threshold of 0.5 dv has no 
relation to the analysis Texas performed and is inappropriate. We also 
note that we discuss in the preamble to the final Regional Haze Rule 
and Guidelines for BART Determinations that a threshold less than 0.5 
dv may be appropriate.\133\
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    \133\ ``. . ., if there were 100 sources each changing 
visibility by 0.1 deciviews, the total impact would be a 10-deciview 
change in visibility. In this hypothetical example, all 100 sources 
would be contributing, in equal amounts, to substantial visibility 
impairment . . . .'' 70 FR 39121.
---------------------------------------------------------------------------

    Even setting aside Texas' approach of aggregating sources with 
varying impacts on visibility, the use of a 0.5 dv threshold as applied 
by Texas for determining the significance of visibility benefits of all 
controls combined would have ensured that little visibility improvement 
would occur during this planning period. Texas and Oklahoma 
acknowledged in their SIP submittals that sources in Texas have a large 
impact on visibility at the Wichita Mountains; indeed, the visibility 
impacts at this Class I area from Texas point sources are several times 
greater than the impacts from Oklahoma's own point sources. Based on 
CENRAP 2018 modeling, all point sources in Texas combined have a 
visibility impact in terms of light extinction of 10.58 
Mm-\1\ at the Wichita Mountains, which based on ``dirty'' 
2018 CENRAP projected background conditions equals a 1.34 dv impact for 
the 20% worst days. Therefore, adopting the 0.5 dv threshold, using 
Texas' approach to assessing reasonable progress measures, would 
require the identification of a control set large enough (and with a 
correspondingly large total cost) to address over one-third of the 
total impacts from all Texas point sources, before the visibility 
benefit would be considered significant. To put this into context, 
achieving the national goal at the Texas Class I areas will require 
just over ten deciviews of improvement (approximately a reduction in 
light extinction of 35 Mm-\1\), a task that EPA has 
estimated could reasonably take until 2064. Given that the Regional 
Haze Rule recognizes that improving visibility is an iterative process 
that will take many years, declining to establish any additional 
measures to ensure reasonable progress until Texas could identify a 
combined set of cost-effective and affordable controls that could 
achieve 0.5 dv or more improvement is unreasonable, especially when 
there are cost-effective and affordable controls that result in 
meaningful visibility improvements towards the goal of natural 
conditions. We also note that delaying even incremental action during 
this first planning period pushes out the likely date of achieving 
natural conditions well past 2064.
    Comment: Earthjustice stated that based on its analysis,\134\ our 
proposed FIP would result in billions of dollars in public health 
benefits. According to Earthjustice, the same pollutants that cause 
visibility impairment also cause significant public health impacts. 
Nitrogen oxides are precursors to ground level ozone, which is 
associated with respiratory diseases, asthma attacks, and decreased 
lung function. Similarly, sulfur dioxide increases asthma symptoms, 
leads to increased hospital visits, and can form particulates that 
aggravate respiratory

[[Page 325]]

and heart diseases and cause premature death. We received many 
additional comments from groups, private citizens, and a member of 
Congress that expressed similar public health, welfare, and economic 
benefits, including ecosystem and tourism benefits.
---------------------------------------------------------------------------

    \134\ Written Report of George D. Thurston Regarding the Public 
Health Benefits of EPA's Proposed Rulemaking Regarding Texas And 
Oklahoma Regional Haze, April 18, 2015. Visibility And Health 
Modeling Technical Support Document to Comments Of Conservation 
Organizations, prepared by Dr. H. Andrew Gray, April 20, 2015.
---------------------------------------------------------------------------

    Response: We appreciate the commenters' concerns regarding the 
potential health benefits of air pollution controls to improve air 
quality In Class I areas. We generally agree that the same emissions 
that cause visibility impairment can also cause health related 
problems, such as respiratory ones. We agree that although our action 
addresses visibility impairment, our FIP requires emissions reductions 
that will result in co-benefits for public health, welfare, and 
economic benefits. However, for purposes of this action, we are not 
authorized to specifically consider these types of benefits under the 
regional haze program.

M. Natural Conditions

    Comment: We received comments from the TCEQ and a number of 
facilities and trade organizations that we should have approved Texas' 
natural conditions calculations for Big Bend and the Guadalupe 
Mountains. These commenters state that Texas rightly discarded our 
default values in favor of its refined estimates in accordance with our 
guidance. In doing so, these commenters state Texas rightly assumed all 
the visibility impairment due to coarse mass and fine soil was due to 
natural causes. Earthjustice stated that Texas did not properly support 
its calculations. Earthjustice stated that because Carlsbad Caverns in 
New Mexico (approximately 40 miles from the Guadalupe Mountains) uses 
the same monitor and we previously approved New Mexico's use of our 
default natural conditions estimate, allowing Texas to use a different 
value is inconsistent.
    Response: We agree with the commenters that the Regional Haze Rule 
and our guidance \135\ do allow states to develop an alternate approach 
to estimate natural visibility conditions. However, in adopting an 
alternate approach, that approach must be fully supported and 
documented. The TCEQ's analysis and our own observations do support a 
conclusion that much of the contribution of coarse mass and fine soil 
to the visibility impairment at the Guadalupe Mountains and Big Bend is 
due to natural sources. They do not demonstrate that 100% of this 
contribution is due to natural sources. Like us, the FLMs did not agree 
with the assumption that 100% of the coarse mass and soil was natural, 
and pointed to human activity in the region. The FLMs ``suggested that 
the commission could judiciously use 80 percent as the natural source 
of coarse and fine dust and 20 percent of coarse and fine dust due to 
human activity.'' \136\ Although the TCEQ presented the FLM's 
suggestion in its SIP, it ultimately adopted its own estimate, based on 
its unproven 100% coarse mass and soil assumption. Another option that 
we noted in our proposal that was open to the states, and the one we 
used in proposing the natural conditions for the Texas Class I areas in 
our FIP, was the ``new IMPROVE equation'' that was adopted for use by 
the IMPROVE Steering Committee in December 2005.\137\ This refined 
version of the IMPROVE equation provided more accurate estimates of 
some of the factors that affect the calculation of light extinction. 
The TCEQ started with this refined version of the IMPROVE equation, but 
further altered some of its parameters concerning the contributions of 
coarse mass and fine soil, without adequate documentation. We found 
that the TCEQ's documentation was flawed, but we are under no 
obligation to follow in the TCEQ's footsteps and make whole its 
methodology, when we had already provided guidance with default natural 
visibility conditions, which were further refined by the 2005 IMPROVE 
Steering Committee. We agree with Earthjustice that it is reasonable to 
expect that both Carlsbad Caverns and the Guadalupe Mountains should 
have the same or nearly the same natural conditions. We urge Texas and 
New Mexico to work together to resolve this issue in the next planning 
period. Even as we are disapproving Texas' natural conditions 
estimates, we conclude that our determinations for emissions 
limitations for EGUs in the FIP for the first planning period would be 
justified on the basis of natural conditions estimates at either levels 
in the SIP or the levels in the FIP, given the level of visibility 
impairment at each Class I area above the different estimates for 
natural conditions and the availability of cost-effective controls at 
those sources with the largest visibility impacts that result in 
meaningful progress towards the natural visibility goal. Furthermore, 
as we noted in our proposal, based on both our recalculated natural 
conditions and the Texas natural condition estimates that we are 
disapproving, Texas' Class I areas are not projected to meet the 
uniform rate of progress in 2018 according to the CENRAP modeling and 
are not projected to meet the goal of natural visibility conditions by 
2064.\138\
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    \135\ Guidance for estimating natural visibility conditions 
under the Regional Haze Rule, EPA, September 2003, p 1-11.
    \136\ Appendix 2-2 of the Texas Regional Haze SIP.
    \137\ The IMPROVE program is a cooperative measurement effort 
governed by a steering committee composed of representatives from 
Federal agencies (including representatives from EPA and the Federal 
Land Managers) and regional planning organizations. See our proposal 
for additional information on the IMPROVE program and the new 
IMPROVE equation.
    \138\ 79 FR 74832
---------------------------------------------------------------------------

    Comment: Luminant's contractor AECOM noted that in developing its 
SIP, Texas found that some of the haziest days at its two Class I areas 
are the result of uncontrollable natural conditions such as windblown 
dust and wildfire emissions. AECOM developed a daily threshold 
percentage of total aerosol extinction \139\ caused by CM, OMC, and 
soil species for each Texas Class I area. This threshold was developed 
by constructing histograms of the 20% worst days for a ``noticeable 
step-up in frequency'' of higher contributions of CM, OMC, and soil. 
AECOM then added this additional extinction to our default natural 
conditions extinctions, resulting in alternate natural conditions 
estimates that it suggests we adopt. AECOM states that with these new 
natural conditions, the uniform rates of progress will be met for Big 
Bend and the Guadalupe Mountains.
---------------------------------------------------------------------------

    \139\ Note that although natural conditions are ultimately 
expressed in deciviews (dv), the IMPROVE equation first calculates 
aerosol extinctions by contributions to extinction by all relevant 
species, of which coarse mass and fine soil are two. Total 
extinction is then converted to deciviews.
---------------------------------------------------------------------------

    Response: Although AECOM restricts its assumption to specific days, 
it nevertheless assumes that all coarse mass, organic mass carbon and 
soil visibility impacts at Big Bend and the Guadalupe Mountains are 
100% due to natural causes. AECOM provides no documentation to support 
this conclusion. Although we agree that much of those species 
contributions are due to natural sources, we do not believe that all of 
these contributions are due to natural sources. Fires, windblown CM and 
soil do have both anthropogenic and natural origins. As an initial 
matter, we believe that AECOM erred in assembling its histograms. We 
reconstructed these histograms and note they differ significantly from 
those AECOM presented. In fact, we believe the ``noticeable step-up in 
frequency of higher contributions of CM, OMC, and soil (i.e., from 
right to left)'' that AECOM points to is more muted for

[[Page 326]]

both Class I Areas when the histograms are assembled correctly, to the 
point it is essentially absent for the Guadalupe Mountains. We noted 
other problems that cause us to conclude that AECOM's methodology 
should not be used. Moreover, under the Regional Haze Rule, even if it 
were concluded that the uniform rate of progress will be met for Big 
Bend and the Guadalupe Mountains, this does not change the requirement 
that the reasonable progress goals be selected based on proper 
consideration of the four factors. As discussed in the proposal and the 
RTC document, the uniform rate of progress is not a ``safe harbor'' 
under the Regional Haze Rule.

N. Consistency With Our Other Regional Haze Actions

    We received a number of comments alleging specific instances of 
inconsistency with our previous SIPs and FIPs, as well as with our 
regional consistency rules at 40 CFR 56.5(a)(1) and (2). We have 
extracted all of these alleged instances of inconsistency, and we 
address them in detail in a separate consistency section within our RTC 
document. We recognize that we have a duty to ensure our regional haze 
actions are carried out in accordance with the CAA, Federal 
regulations, and our policies, and are as consistent as reasonably 
possible with other regional haze actions as required under our 
regional consistency rules (40 CFR 56.5(a)(2)), recognizing the fact-
specific nature of individual regional haze plans and determinations. 
As we discuss below, we believe that in this action, which is one of 
the last remaining regional haze SIP reviews of the first planning 
period, we have been as consistent with our previous actions as is 
reasonably possible. We disagree that our action is inconsistent with 
the reasonable progress requirements or our prior SIP actions. While 
our regional consistency regulations and policies require us to carry 
out our actions pursuant to the CAA in a consistent manner across EPA 
regions as reasonably as possible, they do not require uniformity 
between those actions in all circumstances and instead, ``allow for 
some variation'' in actions taken in different regions.\140\ As 
explained in detail in the separate consistency section of our RTC 
document, we believe that we have acted consistently with the CAA and 
our regional haze regulations in taking these specific actions for 
Texas, and in accordance with 40 CFR 56.5, our final action is ``as 
consistent as reasonably possible'' \141\ with other actions given the 
specific facts presented in Texas and Oklahoma. We thus disagree with 
these comments. We note that staff from Region 6 have worked closely 
with EPA headquarters throughout the proposed and final actions 
regarding the Texas and Oklahoma regional haze requirements, including 
in the analysis and conclusions contained in the SIP and FIP 
determinations included in this final rule. As explained fully in our 
RTC document, we note that commenters' citation to the National 
Environmental Development Association's Clean Air Project v. EPA (NEDA 
CAP) case is distinguishable from our action here.\142\
---------------------------------------------------------------------------

    \140\ 80 FR 50258.
    \141\ 40 CFR 56.5(a)(2).
    \142\ National Environmental Development Association's Clean Air 
Project v. EPA (NEDA CAP), No. 13-1035 (D.C. Cir., May 30, 2014).
---------------------------------------------------------------------------

    Developing solutions to the complex problem of regional haze 
requires effective consultation among states. During the first planning 
period, the states worked together through RPOs to help develop their 
regional haze SIPs. To assist in this effort, we provided tens of 
millions of dollars to the RPOs following the issuance of the 1999 
Regional Haze Rule to fund the development of the technical tools and 
analyses necessary to address regional haze and to facilitate 
consultation among the states. The states set up five RPOs to address 
visibility impairment from a regional perspective. The technical 
analyses done by the RPOs for the first round of regional haze SIPs 
greatly increased the understanding of the problem of visibility 
impairment at the Federal Class I areas, including that of the specific 
contribution of different species of pollutants.
    Given the regional differences in the degree of visibility 
impairment, the pollutants of concern, and the impacts of fire and 
international emissions, we did not prescribe a one size fits all 
approach to reasonable progress. The RPOs accordingly adopted somewhat 
different approaches to recommending potential measures to ensure 
reasonable progress. However, the RPOs and the states all agreed that 
large stationary sources of SO2 are the typically the 
primary cause or one of the primary causes of anthropogenic visibility 
impairment at this time. In addition, in some regions of the country, 
the RPOs and the states also recognized NOX as a similarly 
important cause of visibility impairment.
    In our review of the regional haze SIPs, we have attempted to take 
into account the differences among states in assessing the 
reasonableness of each state's SIP submittal. By its nature, each 
regional haze decision is a very fact specific determination requiring 
the consideration of multiple factors. After examining all instances of 
perceived inconsistency with other actions, we believe that when all of 
the factors are considered in their full context, the situation for 
Texas and Oklahoma differs sufficiently from these other actions cited 
as being inconsistent with this action to warrant the approach that we 
have taken. Furthermore, we found that in many instances some 
commenters reproduced incomplete quotes from our previous actions, or 
otherwise took those quotes out of their proper context, leading to an 
inaccurate characterization of the facts in some cases.\143\ Often a 
sentence immediately preceding or following the reproduced quote in 
fact provided that context. In other cases, commenters called out a 
particular difference between some aspect of our technical analysis in 
comparison to what was used in a previous SIP or FIP, without providing 
the reasoning for those differences. In many other cases, the 
commenters simply misunderstood or otherwise misinterpreted the 
facts.\144\
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    \143\ See for example: (1) Our response to Luminant's comment 
concerning the ``contribution of coal combustion sources'' in the 
Alaska SIP, (2) Our response to CCP's comment concerning the 
consideration of visibility in the North Dakota SIP, or (3) Our 
response to CCP's comment concerning Texas' use of a $2,700/ton cost 
threshold.
    \144\ See for example: (1) The TCEQ's comment letter at page 14 
concerning the Arkansas-Missouri consultations, (2) the AECT's 
comment letter at page 9 that we did not allow Texas to consider 
emissions from natural sources, such as wildfires and dust storms, 
in establishing natural visibility conditions, (3) The CCP's comment 
letter at page 8 concerning Texas' use of a $2,700/ton cost 
threshold.
---------------------------------------------------------------------------

    Many commenters compared our CAMx modeled visibility impairments or 
improvements with those in other actions modeled using CALPUFF and 
concluded that our proposed visibility improvements were not enough to 
merit controls when compared to those other actions. These commenters 
universally failed to account for the differences between these two 
modeling platforms, the model inputs, and the metrics used.\145\ Many 
of these differences result in CAMx modeled visibility impacts and 
benefits that are much lower than the CALPUFF modeled visibility 
impacts and benefits relied on in other actions. As we have noted and 
discussed in separate responses to comments and the FIP TSD, the 
results

[[Page 327]]

of the CAMx modeling we have utilized in our analysis cannot be 
directly compared to the results of CALPUFF modeling, which has been 
utilized in the vast majority of BART and other reasonable progress/
long-term strategy actions.
---------------------------------------------------------------------------

    \145\ See our FIP TSD, beginning on page A-35, in which we 
explain why key differences in CALPUFF and CAMx preclude the 
comparison of their respective results and why CAMx results for RP 
are generally much less than CALPUFF results for BART for the same 
facility/emissions due to the model inputs and metrics used.
---------------------------------------------------------------------------

    Some commenters criticized us for disapproving the reasonable 
progress and long-term strategy consultations between Oklahoma and 
Texas, when other state-to-state consultations similarly failed to 
result in additional controls. Often these comparisons were made 
without regard to the specific facts, such as the magnitude of the 
visibility impacts that Texas sources have on the Wichita Mountains in 
Oklahoma in relation to the relative impact of the sources in those 
other actions, or the overlooked cost-effective controls that were 
available to Texas sources to address those impacts. Other commenters' 
comparisons simply focused on the result without regard to the 
substance: They noted instances where two other states consulted and 
neither required additional controls, and concluded that Texas was 
being treated unfairly.
    Commenters also argued that our proposed disapproval of Texas' 
reasonable progress analysis was based on Texas' decision not to 
undertake a source-by-source analysis of emission controls. The 
commenters pointed to a number of other regional haze SIPs approved by 
EPA where states had relied on analyses of the reasonableness of 
controls for various source categories. The commenters claimed that 
these examples demonstrate that we accepted analyses of source 
categories in other states and that we should not, therefore, 
disapprove Texas' reasonable progress analysis on the grounds that it 
failed to look at controls on a source-by-source basis. These 
commenters ignore the fact that Texas' reasonable progress analysis 
was, in part, based on a source-by-source analysis. However, Texas set 
that analysis aside in favor of comparing the combined costs of all 
controls-- not those for specific source categories-- against its 
calculation of the total visibility benefit. More importantly, however, 
as we have explained elsewhere in this action, our objection to Texas' 
approach to evaluating potential reasonable progress controls was not 
grounded in whether it used a category or source-by-source analysis. 
Rather, our disapproval of Texas' reasonable progress analysis is based 
on the fact that its flawed methodology ignored cost-effective controls 
that, as we demonstrated in our proposal, would result in significant 
visibility benefits.
    Commenters also raise questions concerning our approval of regional 
haze SIPs where states relied on implementation of CAIR or CSAPR to 
satisfy BART. The commenters argue we repeatedly found that 
participation in these trading programs also satisfied reasonable 
progress obligations for these states. One commenter claimed it would 
be illogical to find that CAIR or CSAPR was an appropriate substitute 
for BART but to then require controls for reasonable progress. We noted 
in 2005 that the determination that CAIR provided for greater 
reasonable progress than BART did not answer the question of whether 
more than CAIR would be required in a regional haze SIP.\146\ As we 
have explained, we are not finalizing our proposal to rely on CSAPR to 
satisfy the BART requirements for EGUs in Texas, and at this point it 
is not certain what Texas' CSAPR budgets will be in the future. 
However, the remand of the CSAPR budgets for Texas aside, we do not 
agree that we have been inconsistent in our treatment of Texas. These 
commenters ignore the meaningful differences between Texas and the 
states cited. These include the significant impacts that point sources 
in Texas have on the visibility at the Wichita Mountains in Oklahoma, 
even after the projected reductions from CAIR/CSAPR, the availability 
of cost-effective controls that would address the largest visibility-
impacting sources, the flaws in Texas' technical evaluation of the 
reasonable progress and long-term strategy provisions, and the flawed 
consultations between Texas and Oklahoma. We also note that Texas 
itself did not rely on its participation in CAIR to satisfy the 
reasonable progress requirements without further consideration of 
controls on its EGUs. Rather, Texas considered controls on a 
combination of EGUs and non-EGUs, but ultimately rejected them based on 
a flawed analysis of the reasonableness of such controls.
---------------------------------------------------------------------------

    \146\ 70 FR 39104, 39143.
---------------------------------------------------------------------------

O. Modeling

    Comment: We received comments that we should have prepared a 
modeling protocol and made it available for public/stakeholder review 
and comment. The commenters state that a modeling protocol is required 
by EPA modeling guidance.
    Response: EPA is not required to develop a modeling protocol and 
take public comment on it. Our guidance and 40 CFR part 51 Appendix W 
do not require us to develop a modeling protocol for our technical work 
conducted to support review or rulemaking. We developed a workplan and 
consulted with national experts at EPA HQ as needed to develop the 
proposal that included modeling files, documentation of how the 
modeling was conducted and results. We included all this information in 
the materials for the proposal and took comment on all aspects of our 
analyses and techniques.
    Comment: We received comments that our selection of the CAMx model 
rather than CALPUFF is inappropriate and unjustified. The commenters 
stated that we did not justify the use of CAMx to model visibility 
impacts from individual sources and at large distances, and our use of 
CAMx here is outside of the model's capabilities. Furthermore, these 
commenters assert that our concerns regarding using CALPUFF are not 
clear, and they have concerns that overprediction of impacts are also 
present in CAMx and therefore do not justify the use of CAMx. These 
commenters also state that we failed to consider and discuss bias and 
uncertainty in the modeling results and instead relied on the model 
predictions as definitive results.
    Response: We did include a number of reasons in our proposal and 
Modeling TSD for our selection of the photochemical grid model CAMx 
over CALPUFF. One of the primary reasons is we evaluated the Texas SIP 
for reasonable progress and not BART, and the differences in the 
purposes of these analyses supports the use of different models when 
the resources are available to utilize a photochemical model. 
Reasonable progress requires the evaluation of changes in emissions 
from one or more facilities on visibility impairment at downwind Class 
I areas, in order to properly account for chemical transformations of 
those emissions, the model used must also include the other pollutants 
in the airshed, for which CALPUFF is not as well suited. Reasonable 
progress analyses typically look at the changes in visibility on the 
20% worst days, and this evaluation was done by most states, including 
Texas and Oklahoma, by utilizing a photochemical grid model (PGM) such 
as CAMx or CMAQ and not CALPUFF. Therefore, our use of CAMx for 
evaluation of additional potential controls is consistent with the 
state's SIP submission.
    We also discussed our selection of CAMx vs. CALPUFF and included in 
the Modeling TSD a number of references to performance analysis 
comparisons between the two models. There are also many comparisons 
available in journal articles and online that support using a 
photochemical grid model (most of these comparison

[[Page 328]]

studies are found in the Modeling TSD and the rest are in the docket). 
Some of the references we provided in the proposal raised concern that 
the use of CALPUFF could result in model over-prediction and other 
model performance issues at the distances at which we were evaluating 
most of the sources in our proposal. CALPUFF model results are used 
directly, whereas photochemical grid model results such as those 
achieved through use of CAMx are evaluated with Relative Response 
Factors (RRFs) to help remove potential bias concerns. While no model 
is free from bias issues, previous evaluations of the CENRAP databases 
we used for our analyses have been evaluated and the CENRAP CAMx model 
performance was considered adequate because the modeled outputs 
compared well to past measured conditions. As discussed in the 
following response, the only changes to the CENRAP basecase CAMx 
modeling we made were to update both the CAMx model version used and 
the chemical mechanism in order to use the best science and while 
ensuring model performance was still acceptable.\147\
---------------------------------------------------------------------------

    \147\ Additional information is also included in the Environ 
Memorandums for the 2002 and 2018 modeling, (TX166-010-08 
Memo_TXHAZE_2002CAMx_ENV_29July2013, TX166-010-09 
Memo_TXHAZE_2018CAMx 16Sept13), the FIP TSD, and in the modeling 
section of our RTC document.
---------------------------------------------------------------------------

    In sum, there are many reasons for the selection of CAMx over 
CALPUFF for the purposes of this rule making. CAMx is better suited for 
evaluating the reasonable progress metric of improvement on the 20% 
worst days. It is also better suited for evaluating multiple sources in 
a complex airshed. In addition many references point to CALPUFF's 
potential overprediction at the distances at issue here. Any bias 
issues in CAMx are ameliorated by tethering the model to real 
monitoring data, through the use of relative response factors generated 
by modeling of base and future cases to predict future monitored 
values.
    Comments: We received comments that we failed to perform a full 
model performance evaluation and instead compared model results to the 
CENRAP modeling results despite deviations from CENRAP's modeling 
protocol. These commenters also assert that we failed to update the 
modeled emission inventories or consider more recent emissions data, 
such as the 2011 NEI and EPA's recent projected 2018 emission inventory 
showing large reductions from the Mercury Air Toxics Standards Rule 
(MATS). They state that recent monitor data are representative and 
indicate that our modeling is not representative of anticipated future 
conditions and was not considered during model performance evaluation.
    Response: We did not do a detailed model performance of the 2002 
basecase because that had already been done by CENRAP. The only changes 
we made in the 2002 basecase was to use a newer version of the CAMx 
model and an updated chemical mechanism to utilize improvements in the 
science for our analysis and decisions. As we discussed in our proposal 
materials, these changes were not large and did not warrant a full 
model performance evaluation. We did compare model results with 
previous results and determined that model results were very similar 
and deemed acceptable. It is not uncommon in the modeling community to 
do some small updates such as we did and not perform a full updated 
model performance analysis.
    With regard to comments that we should have performed a more 
complete update of the inventory, a full emission inventory update for 
all emission categories such as biogenic, mobile, non-road, area, and 
point sources for 2002 and 2018 was well beyond the scope of our review 
of the SIP submittal. Such an update was not necessary to evaluate 
whether the modeling and analyses submitted with the original SIP could 
have led to a conclusion that additional reasonable progress controls 
are appropriate. Once our evaluation concluded that it could be 
appropriate for some sources to be better controlled for reasonable 
progress, we did do minor updates to evaluate the most recent emission 
levels of EGUs in Texas for the ones being further evaluated for 
potential controls in our 2018 emissions. Because of the additional 
focus on these particular sources it was appropriate to use more up to 
date emissions. We also used the most recent CAMx model version and 
updated chemical mechanism that included improvements to the source 
apportionment of single point sources and plume in grid algorithms to 
use the most recent science for our evaluations.
    We evaluated the existing CENRAP 2002 and 2018 emission inventories 
and whether to update parts of these emission inventories in 2018. 
After our initial modeling analyses, we did update emissions for the 
EGUs evaluated for potential controls to use recent actuals in the 2018 
modeling, which were thought to better represent emissions from EGUs in 
Texas based on comments from Texas and EGU owners.\148\ We also updated 
the 2018 emissions for two other sources based on permitting and 
additional controls. We considered updating the EGU inventory with the 
emissions inventory from the modeling performed for the MATS 
rulemaking. At the time of proposal, the best information available was 
that no other major controls were planned to be installed on EGUs in 
Texas for SO2 emissions in response to MATS, therefore using 
the recent actuals that we used for 2018 emission rates (prior to any 
potential reasonable progress controls) was the most reasonable 
emission inventory to use in our further modeling.
---------------------------------------------------------------------------

    \148\ Texas comments on Draft IPM modeling conducted by EPA for 
potential national rule making platform provided on June 26, 2014. 
In this docket's materials as ``TCEQ comment letter to EPA on draft 
modeling platform dated June 24, 2014 2018 EMP signed.pdf''
---------------------------------------------------------------------------

    Lastly, we disagree with the commenter that the SIP modeling and 
our further evaluation of 2018 expected levels are not representative. 
In fact, the recent ambient monitoring data at the IMPROVE sites in the 
three Class I areas (2011-2013) are influenced by meteorology that has 
lower than normal transport of pollution from sources in Texas when 
compared to the base period on which projections are based (2000-2004) 
and to the 30-year meteorology analysis of transport to the three Class 
I areas (1984-2013). Thus, examining the 2011-2013 time period 
overstates the progress that can be expected over long term. In 
response to comments and information provided we conducted further 
analysis to appropriately evaluate whether the base period was suited 
for projections to 2018 and also an analysis of how the meteorology 
accompanying the more recent monitoring data for 2011-2013 compared to 
normal meteorology conditions. We further note that 2014 also was not 
quite a normal year \149\ and likely similarly biased low for 
visibility impacts at the Class I areas, but even so monitoring data in 
2014 did increase compared to the 2011-13 data. Overall, we conclude 
that our evaluation of 2002 and 2018 levels and the controls needed for 
reasonable progress are based on representative periods and that recent 
monitoring trends are not as representative and not expected to 
continue if meteorology is more in line with 30-year climatological and 
transport norms.
---------------------------------------------------------------------------

    \149\ Some preliminary analyses of meteorology and pollution 
levels in 2014 indicated a higher frequency of cold fronts during 
the summer of 2014 that led to cleaner air from the arctic mixing 
with the air in the region and resulted in lower pollution build-up 
and transport of pollution to Class I areas in Oklahoma and Texas.
---------------------------------------------------------------------------

    Comment: We received comments that CAMx is not the approved model 
in 40 CFR part 51, appendix W for

[[Page 329]]

modeling long-range transport for visibility.
    Response: Neither the regional haze regulations nor appendix W 
requires the use of a specific preferred model for photochemical grid 
modeling for visibility (regional haze), but we have approved the use 
of regional scale photochemical grid models such as REMSAD and 
CMAQ.\150\ CAMx is another regional scale photochemical grid model that 
was utilized by the RPOs and states and approved by EPA. CENRAP 
conducted its final CAMx source apportionment modeling for the regional 
haze analysis to be utilized in consultations of its nine state members 
in development of their SIPs. We approved most of these SIPs that 
included modeling analyses using CAMx and CAMx is clearly acceptable 
for evaluating long range transport for visibility. Texas also used 
CAMx in its reasonable progress analysis. Furthermore, Texas used CAMx 
to screen small groups of sources and individual sources as part of its 
BART screening and we approved that approach in 2006/7,\151\ based on 
modeling enhancements that Texas contracted to be developed to assist 
in assessing single point source visibility impacts on visibility at 
Class I areas. The visibility impact analysis we performed with CAMx is 
commensurate with the work originally done by Texas in 2006/7 for its 
BART screening. Overall, Appendix W gives us discretionary authority in 
the selection of what models to use for visibility assessments with 
modeling systems, and models such as CALPUFF, CMAQ, REMSAD, and CAMx 
that have all been used for that purpose. In this specific situation we 
determined that CAMx had the best scientific modeling approaches and 
tolls and was best suited for the complex analysis that we needed to 
perform.
---------------------------------------------------------------------------

    \150\ 40 CFR part 51, appendix W, Section 6.2.1 (e&f).
    \151\ EPA, TCEQ, and FLM representatives verbally approved the 
approach in 2006 and in email exchange with TCEQ representatives in 
February 2007 (see email from Erik Snyder (EPA) to Greg Nudd of TCEQ 
Feb. 13, 2007 and response email from Greg Nudd to Erik Snyder Feb. 
15, 2007).
---------------------------------------------------------------------------

    Comment: We received comments that our CAMx modeling significantly 
overstates visibility impacts and improvements on which we based our 
proposal. Commenters describe the ETEX and CAPTEX tracer studies and 
conclude that the results of these studies prove that CAMx 
overestimates visibility impacts by a factor of 3. These commenters 
also claim that these results also show an overestimate in CALPUFF 
results by a factor of 6 (ETEX) or a factor of 3 to 4 (CAPTEX). When 
this factor of 3 over-prediction is taken into consideration, 
commenters state, using the over-prediction amount to scale down 
modeled visibility improvement from controls results in small 
improvements and controls should not be required.
    Response: We disagree with the commenters' conclusion about the 
ETEX and CAPTEX tracer studies and the relevance of these tracer study 
analyses. The analysis provided allegedly indicating that CAMx 
overestimates visibility impacts by a factor of 3 is an incorrect 
interpretation and has flaws in the evaluation and conclusions. Details 
on our technical evaluation and conclusions on why the commenters' 
analysis is flawed is in the RTC document. We do not condone the 
calibration of model results to try to adjust for potential 
biases.\152\ Furthermore, the bias amount indicated by the commenter is 
flawed and is based on limited sampling of model performance 
evaluations that exist. As stated in a response above, our CAMx 
modeling analysis utilized a technique called RRF that limits the 
potential impacts of modeling performance issues since the modeling 
results are used in a relative sense and absolute modeling values are 
not directly used. Due to this and other reasons, we do not think that 
the CAMx modeling overstates the impacts. In fact, several pieces of 
information indicate the impacts may be underestimated (see modeling 
section of the RTC document for full discussion and references). Some 
information indicates that using Plume-In Grid may result in 
underestimation of a source's impacts. As discussed previously, in 
particular in the Cost versus Visibility Benefit and Modeling sections, 
we also disagree that the impacts are small, and we do think the 
impacts are large enough and the benefits of lowering emissions to meet 
the FIP emission limits are great enough to require these reductions. 
As discussed in a separate response to comment in this section, the 
CALPUFF modeling submitted by the commenter had flaws and is not 
appropriate even before they did their inappropriate scaling of 
results.
---------------------------------------------------------------------------

    \152\ App. W, Section 7.2.9(a) ``. . . Therefore, model 
calibration is unacceptable.''
---------------------------------------------------------------------------

    Comment: Commenters provided back trajectory data (72 hours, 500m) 
using HYSPLIT \153\ and monitored data for 2002 and 2011-2013 for the 
20% worst days for Big Bend, the Guadalupe Mountains, and the Wichita 
Mountains. They conclude that these data show that only a small number 
of back trajectories \154\ come from regions with sources being 
analyzed and considered for controls. For Big Bend, the back-
trajectories submitted by the commenters show the majority of back-
trajectories coming from Mexico. For the Guadalupe Mountains, back-
trajectories also primarily came from Mexico and visibility impairment 
is mostly due to natural sources. Back-trajectories for the Wichita 
Mountains rarely come from sources that we are proposing to control.
---------------------------------------------------------------------------

    \153\ HYSPLIT is a model developed by NOAA to utilize national 
meteorological modeling files to assess potential air transport.
    \154\ The HYSPLIT model is designed to utilize archived 
meteorological fields to generate back trajectories. The model user 
will pick a certain receptor (in this case one of the Class I Areas) 
and a specific time (in this case an hour on the day when monitoring 
indicated there was high visibility impairment) and then the model 
will assess the meteorological fields and use the wind speed and 
direction for previous hours to indicate a centerline trajectory of 
where the air that was monitored was in the hours before the day and 
time selected. In essence the product is usually a jagged curved 
line with hourly wind vectors that traces back a centerline for a 
number of hours (example 72 hours). The back trajectory is a 
centerline of the wind and the model user has to keep in mind that 
dispersion and mixing occur so there are areas on either side that 
can contribute as well and the further back in time the back 
trajectory is processed the wider the areas on either side of the 
centerline that could have contributed becomes.
---------------------------------------------------------------------------

    Response: The commenters' back trajectory analysis for the base 
period and 2011-2013 is flawed and did not follow the NOAA draft 
guidance they cited and appropriate HYSPLIT modeling techniques.\155\ 
In addition, our evaluation, discussed in the modeling section of the 
RTC document, shows that the 2011-13 time period is not representative 
of climatological norms regarding the transport wind flows to the three 
Class I areas. We also find that the base time period 2000-2004 was 
more representative of climatological norms.
---------------------------------------------------------------------------

    \155\ NOAA is National Oceanic and Atmospheric Administration. 
NOAA is the developer of HYSPLIT and has previously provided draft 
guidance on the use of the HYSPLIT model.
---------------------------------------------------------------------------

    We reached these conclusions by performing our own HYSPLIT modeling 
of a 30-year period (1984-2013) and concluded that in years with wind 
flow patterns consistent with the climatological norms over that period 
a significant number of days have back trajectories that did include 
areas where the sources proposed for additional controls are located. 
Furthermore our analysis of the 2011-13 period which was less 
representative of normal pollution transport patterns also showed a 
number of back trajectories went through or near the areas with the 
sources being considered for controls. Therefore these back 
trajectories do indicate the sources being considered

[[Page 330]]

for control would be expected to reduce visibility impacts at the three 
Class I areas.
    Our analysis of 30-years of back trajectories to assess whether the 
2011-13 and 2000-2004 periods were within the climatological norm also 
indicated that the base period (2000-2004) was more similar to the 
climatological norm than the 2011-2013 period, so we conclude that 
using the base period is more representative for projecting 2018 
levels.
    In sum, the number of trajectories that go near the sources in 
Texas is large enough to not rule them out from consideration for 
potential control. In general, we have treated back trajectories as a 
tool to potentially screen an area out if no trajectories go through an 
area but if some trajectories go through an area then the area may be 
evaluated further or, as in this case, the full analysis may rely on 
more sophisticated tools such as CAMx.
    The commenter indicated that a number of back trajectories went 
through Mexico but failed to mention that many of these also went 
through Texas. Therefore, sources in Mexico and Texas could contribute 
emissions to the visibility impairment at the Class I Areas. We have 
concluded that the back trajectory data provided by the commenter do 
not support their assertions that transport from the regions with those 
sources we are controlling is rare. The data they have provided are 
inconsistent with the guidance and general practices and are for years 
that are not representative of normal climatological patterns with 
respect to transport wind flow to the Class I areas. Furthermore, the 
back trajectories submitted by the commenter do in fact show transport 
from regions of Texas for some days. Our additional analysis identified 
the normal wind patterns over a 30-year period and determined that 
based on normal conditions, transport does occur from the regions in 
Texas with those sources we are controlling.
    HYSPLIT is a meteorological transport model but does not assess the 
dispersion of and impacts from pollutants from differing sources and 
does not have chemistry to correctly assess the potential impacts of 
secondary particulate matter. We used the CAMx model, which does 
account for pollutants and utilizes atmospheric chemistry mechanisms to 
calculate changes in visibility impacts from the proposed emission 
reductions at specific sources. As discussed in a response to comment 
above in this section, photochemical grid models such as CAMx are best 
suited for this analysis and determination of the benefit of potential 
emission reductions.
    Comment: Commenters submitted CALPUFF modeling for Coleto Creek 
Unit 1 for 2004-2006. Results indicate that visibility impacts from the 
facility are below the 0.5 dv subject to BART threshold. The commenter 
states that tracer studies suggest CALPUFF overestimates visibility 
impacts by a factor of 4.5 (on average) and adjusts the CALPUFF model 
results down by this factor. The commenter concludes that Coleto 
Creek's calibrated impacts are very small and any visibility benefit 
from controls would be even smaller.
    Response: We have reviewed the CALPUFF modeling provided for Coleto 
Creek Unit 1 and do not concur with the conclusions that Coleto Creek's 
impacts are small. We have a number of concerns with the CALPUFF 
modeling provided: (1) It utilizes the wrong years for modeling; (2) 
the modeling does not comply with the original BART CALPUFF modeling 
protocol that Texas and EPA approved; and (3) it uses some 
inappropriate assumptions, including the calibrating of modeling 
results based on limited analyses using other databases and locations 
that are not directly comparable to assessing impacts from Coleto 
Creek's units. The 0.5 dv threshold was utilized as a BART threshold, 
but our action is for reasonable progress and the 0.5 dv threshold was 
not set as an applicable threshold in the Regional Haze Rules for 
reasonable progress (see response in the Cost versus Visibility Benefit 
section of this document). We used a photochemical grid model which is 
more scientifically robust than the CALPUFF modeling system and is more 
appropriate for longer transport distances, such as the distances 
between Coleto Creek and the Class I areas in Texas and Oklahoma. We 
performed a multi-tiered analysis in order to identify the Texas 
facilities with the largest impacts on visibility at Class I areas (in 
Texas and Oklahoma) and Coleto Creek's facility did rank as one of the 
largest impacting sources of the more than 1,600 sources considered in 
Texas. As discussed in another response in this section, we do not 
condone calibrating CALPUFF model output values. We discuss the 
commenters' use of the tracer studies in the RTC document but their 
analysis and conclusions are flawed and not representative of the 
larger collection of information available that also is discussed in 
more detail in the RTC document. In conclusion, based on our analysis 
with CAMx, we think both the visibility impacts of the sources and the 
benefits from the proposed emission reductions are large enough to be 
beneficial for reasonable progress.
    Comment: Focusing on visibility impacts on the 20% worst days 
ignores larger impacts from these sources and other sources on other 
days. This approach is also inconsistent with CALPUFF modeling for BART 
of the maximum impact from a source for comparison with a 0.5 dv 
threshold. Consideration of impacts on other days will identify sources 
for control analysis that will result in visibility improvement on 
other days and make progress towards the goal of natural visibility 
conditions.
    Response: Under the reasonable progress and long-term strategy 
requirements of the Regional Haze Rule, the state or EPA in 
promulgating a FIP must establish reasonable progress goals that 
provide for improvement on the most impaired days, demonstrate that the 
established goals are reasonable and develop coordinated emission 
management strategies to achieve those goals. The most impaired days 
are defined as the average visibility impairment for the 20% of 
monitored days in a calendar year with the highest amount of visibility 
impairment.\156\ Because the rule focuses on improving visibility on 
the most impacted days, we believe it is reasonable and appropriate to 
focus our analysis on sources that significantly impact visibility on 
those 20% worst days. While we generally agree with the commenter that 
this may ignore visibility impacts from sources that impact visibility 
on days other than the most impaired days, visibility impairment on the 
current 20% worst days will be reduced as a result of controls 
implemented to address visibility impairment for this first planning 
period, and we believe that in the future the most impaired days may 
shift and be impacted by different sources. Analysis and development of 
future regional haze SIPs for future planning periods can aim to 
address those sources that impact any new set of most impaired days. 
Furthermore, targeted reductions at those sources that significantly 
impact the most impaired days will also result in improved visibility 
on days outside of the most impaired days.
---------------------------------------------------------------------------

    \156\ This is the definition in the Regional Haze Rule, but it 
contains an obvious typographical error. It should be interpreted to 
mean that visibility on the most impaired days is defined as stated.
---------------------------------------------------------------------------

    CALPUFF modeling is used to provide estimates of the maximum 
visibility impacts from a source based on maximum emissions and 
simplified chemistry, irrespective of the relationship to the 20% worst 
days. It is

[[Page 331]]

possible that CALPUFF modeling of some of the subset of the 38 sources 
identified based on Q/d that were not analyzed for additional controls 
could show significant impacts on the maximum or 98th percentile day, 
but our CAMx photochemical modeling (which includes all emissions 
sources and has a realistic representation of formation, transport, and 
removal processes of particulate matter that causes visibility 
degradation) provides additional information that allows for the 
identification of the sources with the greatest impacts on the 20% 
worst days.
    Comment: EPA should have required additional controls on sources 
beyond what we proposed in our FIP to assure even greater reasonable 
progress. Certain controls are reasonable and consistent with the 
proposed controls when impacts at Class I areas other than the Texas 
Class I areas and the Wichita Mountains are considered. Some specific 
facilities, such as Oklaunion and H.W. Pirkey, fall above the 0.3% 
impact threshold for impacts at the Class I areas of interest and 
should have been evaluated for controls. EPA evaluated controls for 
Parish and Welsh but did not require controls despite significant 
visibility benefit and reasonable costs.
    Response: We focused our control analysis on the Texas Class I 
areas and the Wichita Mountains. As discussed in more detail elsewhere 
in this action, we are disapproving portions of the Texas and Oklahoma 
regional haze SIPs, including the Texas long-term strategy 
consultation, the Oklahoma reasonable progress consultation, the 
Oklahoma established reasonable progress goal for Wichita Mountains and 
the Texas reasonable progress/long-term strategy analysis and 
consideration of reasonable controls at Texas sources necessary to 
establish the Texas and Oklahoma reasonable progress goals. In 
developing a FIP to address the deficiencies in the Oklahoma and Texas 
SIPs, we had to analyze the visibility impacts and the availability of 
reasonable progress controls at Texas sources that impact visibility at 
the two Texas Class I areas and the Wichita Mountains and establish 
reasonable progress goals including consideration of an appropriate 
reasonable progress control analysis for these areas. We expect New 
Mexico, Arkansas, Louisiana, and Missouri to consider remaining impacts 
from Texas sources on their Class I areas including the information on 
visibility impacts from specific sources provided by our analysis, as 
well as incorporate corrections and updates to emission reductions in 
consultations and development of their regional haze SIPs for the next 
planning period.
    We disagree with commenters and we note, as further detailed in our 
RTC document, that when recent actual emissions and unit-level 
visibility impacts are considered, the units at the facilities 
identified by the commenters, such as Oklaunion and Pirkey, fall below 
the percent of visibility impairment threshold we established to 
identify units for additional control analysis. This threshold was 
established to identify a reasonable set of units that had the greatest 
visibility impacts for additional control analysis for this planning 
period. We note that any increases in actual emissions at these 
facilities in the future should be considered during development of the 
regional haze SIP for future planning periods. In future planning 
periods, as the facilities with the greatest impacts are controlled, 
the percent of total visibility impairment due to these lower impact 
facilities will increase and they in turn should be considered for 
additional control.
    Considering the visibility benefits and costs, we disagree that we 
should have required controls on units at Parish and Welsh. In 
evaluating the cost of controls, we also weighed how effective the 
reductions were in achieving visibility benefits. We considered the 
anticipated visibility benefit in deciviews (for both a ``dirty 
background'' and a ``clean background'') as well as the reduction in 
extinction and the percentage of visibility impairment addressed by the 
controls. Based on our evaluation of these visibility metrics within 
the cost factor of the four-factor reasonable progress analysis, we 
determined that additional controls on Parish and Welsh were not 
required for reasonable progress for the first planning period. In the 
FIP TSD and the proposed FIP, we note lesser visibility improvement 
benefits at the three Class I areas for the W. A. Parish and Welsh 
units compared to the benefits at other facilities that mainly impact 
the Wichita Mountains. We also note that when considering the costs of 
controls and the relative visibility benefit, the Parish scrubber 
retrofits would be slightly more expensive with respect to $/ton but 
would be much less effective in improving visibility at the Wichita 
Mountains, when compared to the required controls at the Monticello or 
Coleto Creek units. For the Welsh scrubber retrofits, the costs ($/ton) 
would be approximately 50% greater than the cost of scrubber retrofits 
at Monticello or Coleto Creek and would result in approximately 50% 
less visibility improvement at the Wichita Mountains. We also 
considered comments on cumulative visibility benefits of these controls 
and determined that the cumulative visibility benefits of each new 
scrubber at the Parish and Welsh units would be less than those at each 
of the units where we proposed scrubber retrofits and less than that at 
each of the units with proposed scrubber upgrades with the exception of 
Limestone, at a cost significantly higher than the estimated cost of 
scrubber upgrades. Similarly, the total cumulative visibility benefit 
of controlling the three units at Welsh and the four units at Parish 
would be less than half the benefit from all the required scrubber 
retrofits or all the required scrubber upgrades, and at a greater 
average $/ton cost.\157\ While controlling the Welsh and Parish units 
would result in some additional cumulative visibility improvement, 
based on our evaluation and weighing of the cost and consideration of 
the visibility benefits of these controls at the Wichita Mountains, we 
determined their individual projected visibility improvements do not 
merit the installation of scrubbers at this time. We encourage the 
State of Texas to re-evaluate this determination as part of its next 
regional haze SIP submittal and we note that as the required controls 
are implemented the significance of impacts and potential benefits from 
the Parish and Welsh units will increase in terms of percentage of 
extinction. As discussed in the modeling section of the RTC document, 
we disagree with comments that this determination is inconsistent with 
the determination to require controls at Tolk Station or with the 
determination of required controls in other states for the purpose of 
reasonable progress.
---------------------------------------------------------------------------

    \157\ See TX-116-007-_33_Vis_modeling_summary.xlsx in the docket 
to this action for visibility benefits of controls.
---------------------------------------------------------------------------

    We agree with the commenter that on a $/ton basis, scrubber 
upgrades on Parish unit 8 are very cost-effective. However, the 
visibility benefit and reduction in emissions from this control would 
be very low when compared to all the other evaluated scrubber upgrades. 
The estimated visibility benefit from upgrading the scrubber would be 
an order of magnitude less than all the other evaluated scrubber 
upgrades and not large enough to require as reasonable progress for 
this planning period.
    Comment: EPA should have analyzed oil and gas sources and 
NOX controls for certain point sources in Texas.
    Response: With regards to comments on additional controls for 
NOX, as

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discussed in the proposed FIP, we agree with Texas that the predominant 
anthropogenic emissions impacting visibility are nitrate and sulfate 
emissions, primarily from point sources.\158\ As described in more 
detail in the FIP TSD, in our initial analysis we focused on point 
sources and we identified facilities with the greatest potential to 
impact visibility based on a Q/d analysis considering both 
SO2 and NOX emissions. We then used photochemical 
modeling to estimate the visibility impacts due to the emissions from 
these facilities, considering SO2, NOX, and all 
other emitted pollutants. Based on the results of that visibility 
modeling, we identified a subset of facilities for additional control 
analysis and determined that the visibility impacts due to these 
facilities was almost entirely due to their sulfate emissions. 
Therefore, we determined that to address the visibility impacts on the 
20% worst days from these sources, it was only necessary to evaluate 
sulfate controls for this planning period. Our analysis identified 
those sources that had the greatest visibility impacts, which we then 
further analyzed for controls. This analysis did not identify any 
individual point sources (with the exception of the PPG Glass Works 
facility) with significant visibility impacts due to NOX 
emissions among the group of sources with the greatest visibility 
impacts. We address our evaluation of NOX controls for the 
PPG Glass Works in our RTC document.
---------------------------------------------------------------------------

    \158\ 79 FR 74838.
---------------------------------------------------------------------------

    Oil and gas emissions are the largest component of area source 
emissions but are only part of the total NOX area source 
emissions. Oil and gas sources that fall within the point source 
category were considered in our initial Q/d analysis and photochemical 
modeling used to identify sources for additional control analysis. 
Similarly with regard to comments on controlling oil and gas sources, 
visibility impacts from NOX emissions from area sources are 
relatively small compared to impacts from point sources of 
SO2 and NOX at the Class I areas impacted by 
Texas emissions. Focusing on point source emissions of NOX 
and SO2 captured those sources with the greatest impacts on 
visibility and was a reasonable approach for this planning period.
    Comment: Visibility impairment from the ``Other 29'' sources not 
analyzed for controls are still significant and additional controls 
should be required. Furthermore, some of the ``1,600 +'' sources not 
further analyzed collectively contribute to total visibility 
impairment.\159\
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    \159\ ``Other 29'' refers to the facilities identified as having 
the greatest potential to impact visibility based on the Q/d 
analysis but were then eliminated from further analysis based on 
photochemical modeling results. ``1,600 +'' refers to all point 
sources in Texas from the TCEQ's 2009 point source inventory.
---------------------------------------------------------------------------

    Response: Our Reasonable Progress Guidance discusses the steps to 
follow in identifying reasonable controls and establishing reasonable 
progress goals. The key pollutants contributing to visibility 
impairment at each Class I area should be determined. ``Once the key 
pollutants contributing to visibility impairment at each Class I area 
have been identified, the sources or source categories responsible for 
emitting these pollutants or pollutant precursors can also be 
determined. There are several tools and techniques being employed by 
the RPOs to do so, including analysis of emission inventories, source 
apportionment, trajectory analysis, and atmospheric modeling'' (page 3-
1). As discussed in more detail in our proposal and in a separate 
response to comment in the modeling section of the RTC document, we 
determined that it was reasonable to focus our analysis on point 
sources of SO2 and NOX.\160\ This was based on 
review of emissions and source apportionment results indicating that 
these sources were most responsible for anthropogenic contributions to 
visibility impairment. We then used a Q/d analysis to identify those 
sources with the greatest potential to impact visibility based on 
emissions and distance. Additional analysis using photochemical grid 
modeling was then completed to estimate the visibility impact from 
those sources. Based on consideration of facility level and estimated 
contributions to visibility from units at the modeled facilities, we 
identified those sources that had the greatest visibility impacts to 
analyze for additional controls. We agree with the commenter that 
collectively the ``Other 29'' sources and ``1,600+'' sources contribute 
a sizeable percentage of the total visibility impairment. However, on 
an individual basis, these point sources have lower contributions and 
smaller potential for visibility improvements relative to the nine 
facilities evaluated for additional controls. For example, the proposed 
controls on only 7 facilities address 5.8% of the total visibility 
impairment at the Wichita Mountains, while controls on all of the 
``Other 29'' sources would address 4.4% of the total visibility 
impairment. Consistent with our guidance, we identified those key 
pollutants and sources with the greatest impact on visibility 
impairment for this first planning period. We also note that the 
``Other 29'' includes impacts from San Miguel and the PPG Glass Works 
facility that were considered for additional controls, and the JT Deely 
units that are scheduled to shutdown in 2018.
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    \160\ 79 FR 74838.
---------------------------------------------------------------------------

    The Regional Haze Rule requires the identification of reasonable 
progress controls and the development of coordinated emission control 
strategies in order to make reasonable progress towards the goal of 
natural visibility conditions. Faced with a very large and unwieldy 
universe of sources, we followed our guidance and chose an approach 
that focused on the portion of the universe of Texas sources that 
contributed the greatest impact to visibility impairment, by 
establishing a threshold of 0.3% contribution to total visibility 
impairment on a unit basis for this planning period, thereby 
identifying a reasonable set of units at nine facilities to analyze for 
additional controls.\161\ Our four-factor analysis concluded that 
controls on units at seven of the nine facilities analyzed for 
additional controls were required. As these controls are implemented, 
the percentage impact from those facilities not controlled will become 
larger (on a percentage basis) and will be analyzed in future planning 
periods. In other words, some of the ``Other 29'' will be identified as 
the greatest impacting sources and should in turn be analyzed for 
additional reasonable progress controls in a future planning period. 
This methodology can be used as a consistent procedure to identify 
facilities for additional control analysis in this and future planning 
periods and would ensure continuing progress towards the goal of 
natural visibility conditions. The USDA Forest Service commented that 
``the methodology and metrics that EPA used are the most comprehensive 
seen to date for any SIP/FIP in the country that we have reviewed, and 
should serve as a model for future efforts to consider the contribution 
and/or potential benefits of individual sources to visibility.''
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    \161\ As discussed elsewhere, San Miguel has already upgraded 
its scrubber and therefore it was not included in our modeling 
analysis of additional controls and not included among the nine 
facilities discussed here. In our FIP, we are finalizing our 
determination that San Miguel maintains an emission rate consistent 
with recent monitoring data.
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    Comment: We received comments on the methodology used to identify 
sources for analysis. Commenters stated that our analysis, beginning 
with a Q/d analysis and the use of a 0.3% of total impairment threshold 
for identifying

[[Page 333]]

sources for additional analysis was arbitrary, capricious, or improper. 
In addition, commenters contend that the Q/d analysis selects the wrong 
sources because it does not consider stack parameters or meteorology. 
Other commenters suggested that all 38 facilities identified as having 
the greatest potential to impact visibility by the Q/d analysis should 
have undergone a four-factor analysis. We also received comments that a 
lower threshold should have been used, that the threshold was applied 
inconsistently, and that the 0.3% threshold screened out sources that 
have a significant visibility impact and should have been evaluated for 
controls.
    Response: We disagree with the commenters' assertion that our 
analysis, beginning with a Q/d analysis, was arbitrary, capricious, or 
improper. As explained below and elsewhere in this document, our 
complete analysis identified those sources with the greatest visibility 
impacts at the Wichita Mountains and the Texas Class I areas based on 
consideration of a source's emissions, location, and modeled visibility 
impairment. Once identified, we performed additional control analysis 
on these sources to determine through the four-factor analysis if 
controls were available and cost-effective.
    As we discuss at length in the FIP TSD and in our RTC document, we, 
states (including Texas) and RPOs (including CENRAP) have used a Q/d 
analysis to identify those facilities that have the most potential to 
impact visibility at a Class I area based on their emissions and 
distance to the Class I area. These identified facilities could then be 
considered for further evaluation to estimate visibility impacts, and 
then undergo the reasonable progress analysis for determination of 
reasonable progress controls. The BART guidelines \162\ discuss 
identifying sources with the potential to impact visibility based on a 
Q/d approach consistent with the method followed in this action. 
Furthermore, this approach has also been recommended by the FLMs' Air 
Quality Related Values Work Group (FLAG) \163\ as an initial screening 
test to determine if an analysis is required to evaluate the potential 
impact of a new or modified source on air quality related values (AQRV) 
at a Class I area. In the Texas regional haze SIP, the TCEQ relied on a 
Q/d approach as one of the initial steps to identify sources for 
additional analysis.\164\ We used a similar Q/d approach to identify 38 
sources, from the more than 1,600 point sources in Texas that had the 
most potential to impact visibility due to their location and size. In 
other words, we started by looking at every point source in Texas \165\ 
and narrowed the field to a much smaller subset of sources with the 
most potential to impact visibility based on their emissions and 
location. This approach is a widely used method as an initial step to 
evaluate a facility's potential to impact air quality and identify 
those sources with large enough emissions close enough to a receptor to 
need additional analysis. Using this methodology, we considered every 
point source in Texas and narrowed the list to a much smaller list of 
facilities with the greatest potential visibility impacts based on just 
emissions and distance.
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    \162\ See 40 CFR part 51, appendix Y, section III (How to 
Identify Sources ``Subject to BART'')
    \163\ Federal Land Managers' Air Quality Related Values Work 
Group (FLAG), Phase I Report--Revised (2010) Natural Resource Report 
NPS/NRPC/NRR--2010/232, October 2010. Available at http://www.nature.nps.gov/air/Pubs/pdf/flag/FLAG_2010.pdf.
    \164\ TX RH SIP Appendix 10-1. ``The group of sources was 
further reduced to eliminate sources that are so distant from any of 
the ten Class I areas that any reduction in emissions would be 
unlikely to have a perceptible impact on visibility. The list was 
restricted to those sources with a ratio of estimated projected 2018 
base annual emissions (tons) to distance (kilometers) greater than 
five to any Class I area.''
    \165\ The Texas point sources are defined as industrial, 
commercial, or institutional sites that meet the reporting 
requirements of 30 Texas Administrative Code (TAC) Sec.  101.10. 
Permitted point sources in Texas are required to submit annual 
emissions inventories. The data are drawn from TCEQ's computer-based 
State of Texas Air Retrieval System (STARS). Annual emission data 
from 2009 were utilized to calculate the Q/D value for all point 
sources with reported emissions in Texas. 2009 emissions data 
available in the docket as ``2009statesum.xlsx''
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    Following the Q/d analysis, we took the additional step of using 
photochemical modeling, utilizing CAMx with Plume-In-Grid (PiG) and 
Particulate Source Apportionment Tagging (PSAT). As the commenter 
states, the Q/d analysis does not take into account stack parameters, 
meteorological conditions, or chemistry. Given the large geographic 
distribution of sources and distances to the Class I areas, we 
recognized that it was highly likely that only a subset of these 38 
facilities would have the greatest visibility impacts on downwind Class 
I areas once meteorology and transport conditions, atmospheric 
dispersion, chemistry, and stack parameters were taken into 
consideration, as CAMx with PiG and PSAT can do. We determined it was 
appropriate to use photochemical modeling to assess the visibility 
impact from those sources identified by our Q/d analysis. In the same 
way that Q/d is used as an estimate of the potential visibility impact 
due to emissions and distance, the photochemical modeling aims to 
estimate the visibility impacts albeit in a much more refined manner 
that accounts for chemistry and meteorological conditions. We also note 
that some RPOs and states used a combination of back trajectory 
analysis, source apportionment modeling results, and Q/d as a more 
refined approach to identify sources for additional control analysis 
for reasonable progress.\166\ Our modeling results indicated that a 
subset of the 38 facilities were the primary contributors to visibility 
impairment at each Class I area. The results of this modeling were used 
to verify our initial identification of sources and further eliminate 
sources from a full four-factor analysis based on facility-level 
impacts and consideration of estimated unit level impacts, as described 
in detail in the FIP TSD.
---------------------------------------------------------------------------

    \166\ To select the specific point sources that would be 
considered for each Class I area, VISTAS first identified the 
geographic area that was most likely to influence visibility in each 
Class I area and then identified the major SO2 point 
sources in that geographic area. The distance-weighted point source 
SO2 emissions (Q/d) were combined with the gridded 
extinction-weighted back-trajectory residence times. The distance 
weighted (Q/d) gridded point source SO2 emissions are 
multiplied by the total extinction-weighted back-trajectory 
residence times (Q/d * Bext-weighted RT) on a grid cell by grid cell 
basis and then normalized. See VISTAS Area of Influence Analyses, 
2007 available in the docket for this action.
---------------------------------------------------------------------------

    There are a number of different approaches used by states in 
identification of sources for reasonable progress evaluation but these 
approaches usually centered around the general premise of evaluating 
the biggest sources and the biggest impacts on visibility. As we 
explain in the FIP TSD, we considered the visibility modeling results 
in a number of ways to determine a reasonable approach to identify 
those sources with the largest impacts for additional analysis for 
controls for this planning period. We examined the model results for 
extinction and percent extinction of the modeled facilities as well as 
estimated impacts based on more recent actual emissions. We considered 
both facility level and unit level impacts. We concluded that any unit 
with an estimated impact greater than 0.3% would be further evaluated. 
We believe that using a percent impacts approach is appropriate because 
of its linkage to the reasonable progress concept. For example, a 
source that has a smaller absolute impact on a relatively cleaner area 
but a higher percentage impact might be considered for control so that 
the cleaner area can potentially make progress. We used the 0.3% 
threshold only as a way to identify a reasonable

[[Page 334]]

set of sources to evaluate further. At this point, the resulting 
reasonably broad set of sources served as a starting place from which 
to further analyze individual source impacts in the second round of 
modeling, and balance them against any cost-effective controls that 
could be identified.
    In summary, our analysis properly identified the sources in Texas 
with the greatest individual visibility impacts for additional control 
analysis. Commenters are incorrect in their assertion that the 
visibility impacts from the identified sources are miniscule, or that 
we started our analysis with the wrong sources. Starting from the 
entire universe of Texas point sources, we systematically eliminated 
those facilities that had less potential to impact visibility based on 
careful consideration of emissions, location, and finally modeled 
visibility impacts. After identifying those facilities with the 
greatest visibility impacts, we performed the four-factor analysis to 
evaluate whether reasonable progress controls were available and cost-
effective.
    Comment: We received comments that EPA established the deciview as 
the required metric for establishing and tracking progress towards the 
reasonable progress goal. EPA's use of extinction or percent extinction 
and establishment of thresholds is arbitrary, capricious, illegal and 
without precedent.
    Response: We disagree with the commenters that our use of metrics 
other than deciviews for certain purposes is contrary to regulations. 
The commenters fail to distinguish between the metrics used to describe 
overall visibility conditions at a Class I area and the metrics that 
can be used to describe the visibility impairment due to an individual 
source, group of sources, a state's sources, or some other portion of 
the visibility impairment at a Class I area. In describing the overall 
visibility conditions at a Class I area, we established the deciview as 
the principle metric. This applies to the calculation of current, 
baseline, and natural visibility conditions at a Class I area, as well 
as the reasonable progress goals established as the visibility 
condition goal for the Class I area at the end of the current planning 
period. We agree with the commenters that the use of the deciview 
metric is required in a number of places within the rule that discuss 
overall visibility conditions and assessing progress towards meeting 
the desired visibility conditions. Specifically, the state must (1) 
establish reasonable progress goals expressed in deciviews (40 CFR 51. 
308(d)(1)); (2) determine the uniform rate of progress in deciviews (40 
CFR 51.308(d)(1)(i)(B)); and (3) determine the baseline and natural 
visibility conditions expressed in deciviews and the number of 
deciviews by which baseline conditions exceed the natural conditions 
(40 CFR 51.308(d)(2)). Consistent with these requirements, we 
calculated the baseline and natural visibility conditions, the uniform 
rate of progress, and the number of deciviews by which baseline 
conditions exceed the natural conditions in deciviews for Big Bend and 
the Guadalupe Mountains, as well as established reasonable progress 
goals for the Wichita Mountains and the Texas Class I areas in 
deciviews.
    The deciview metric provides a scale that relates to visibility 
perception and therefore is useful in assessing the overall visibility 
conditions that are being or will be perceived at the Class I area. The 
commenters cite to several actions and the Regional Haze Rule where the 
benefits of using the deciview metric are discussed, however this is 
only discussed in the context of overall visibility conditions, such as 
determining current or natural visibility conditions. This is very 
different from the fraction of visibility impairment attributable to a 
source or group of sources. We note that in the final Regional Haze 
Rule, we do in fact mention the use of light extinction as another 
metric that states may choose to use.
    There is no requirement to use the deciview metric in describing 
the visibility impairment due to a source or group of sources as part 
of the analysis required for identifying reasonable controls under 
reasonable progress. In describing how to identify sources or source 
categories responsible for visibility impairment, our guidance \167\ 
provides states with considerable flexibility to utilize various tools 
and techniques that would necessarily involve the use of various 
metrics other than deciviews. Many states and RPOs, including Texas and 
CENRAP, relied on a Q/d analysis, described and discussed in depth in 
separate responses to comments and in our proposed FIP, to identify 
sources for additional control analysis. The Q/d analysis relies on an 
annual emissions divided by distance metric, not deciviews. The VISTAS 
RPO relied on a metric derived from Q/d and residence-time, not 
deciviews.\168\ Some states relied on a simple analysis of emissions to 
determine which sources should be analyzed.
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    \167\ Guidance for Setting Reasonable Progress Goals Under the 
Regional Haze Program, U.S. EPA, OAQPS, June 1, 2007, page 3-1
    \168\ VISTAS Area of Influence Analyses, 2007, available in the 
docket for this action.
---------------------------------------------------------------------------

    When assessing the various contributions to visibility impairment 
due to either source categories or pollutant species from other states 
and international sources, Texas routinely relied on light extinction 
and percent of total visibility impairment metrics. For example, 
Chapter 11 of the Texas regional haze SIP describes the contributions 
due to sulfate, nitrate, and other pollutants on the 20% worst and 20% 
best days at the Guadalupe Mountains and Big Bend in terms of light 
extinction (inverse megameters, Mm-\1\). Similarly, the 
extinction metric is used by Texas (see section 11.2.3 of the Texas 
regional haze SIP) to assess the level of impact on other Class I areas 
from Texas sources. Texas also used the extinction metric to determine 
which states significantly impact the Texas Class I areas, applying an 
impact extinction level threshold of 0.5 Mm-\1\ from all 
sources in a state as a threshold for inviting a state to consult.\169\ 
Source apportionment modeling performed by the RPOs was utilized by 
every state to assess the various contributions to visibility 
impairment at their Class I areas in terms of light extinction and 
percent contribution to total light extinction. The CENRAP PM source 
apportionment tool (CENRAP PSAT tool) utilized by all CENRAP states, 
including Texas and Oklahoma, to review the results of the source 
apportionment modeling provides results in two ways: Light extinction 
(inverse megameters) and percentage of total extinction. In our action, 
we also utilized the methodology and metrics used by the RPOs to 
evaluate the source apportionment results, the only difference being 
that our source apportionment modeling provided information on 
visibility impacts from individual sources instead of source 
categories, or regions/states. In the FIP TSD, we provide information 
on visibility impacts from the individual sources in terms of 
extinction, percentage of total extinction, and in deciviews.
---------------------------------------------------------------------------

    \169\ See Texas Regional Haze SIP Appendix 4-1: Summary of 
Consultation Calls
---------------------------------------------------------------------------

    We evaluated the information in terms of light extinction and 
percentage of total impact to identify a reasonable subset of sources 
with the largest visibility impacts to analyze for additional controls. 
Because the overall visibility conditions at different Class I areas 
can vary greatly, particularly Class I areas in the Eastern U.S. 
compared to Class I areas in the Western U.S., we determined that it is 
not enough to consider just the magnitude of extinction from a 
facility; we must also

[[Page 335]]

consider the percentage of total impairment metric at each Class I 
area. As we state in the FIP TSD, ``We believe that using a percent 
impacts approach is appropriate because of its linkage to the RP 
concept. For example, a source that has a smaller absolute impact [in 
terms of extinction] on a relatively cleaner area but a higher 
percentage impact might be considered for control so that the cleaner 
area can potentially make progress.'' Using the percentage of total 
visibility impairment metric allows us to somewhat normalize the 
extinction differences between Class I areas so that we can utilize the 
same approach at each Class I area and identify a reasonable set of 
sources to analyze that if controlled would result in meaningful 
visibility benefits towards meeting the goal of natural visibility at 
every Class I area. For every Class I area to have the opportunity to 
reach the natural visibility goals, it is necessary to identify the 
sources or source categories that significantly impact visibility, 
identify available controls and analyze whether those controls are 
reasonable. Had we established a strict threshold based on extinction, 
we would have had to establish a different threshold for each Class I 
area. Using a percentage approach, such as the 0.3% of total visibility 
impairment on a unit basis we used in this action, results in 
identification of a subset of sources that includes those sources with 
the greatest visibility impacts at each Class I area. As stated by the 
USDA Forest Service in its supportive comments, the use of this 
methodology and metrics, including the use of a small percentage 
threshold on the 20% worst days is linked to the concept of reasonable 
progress. We believe it could serve as the model for future efforts to 
consider the contribution and potential benefits of individual sources 
to visibility. After identifying which sources to analyze for 
additional controls based on the percentage impact on a unit basis, we 
determined which controls were reasonable based on consideration of the 
four factors, including comparison of cost to the anticipated 
visibility benefit (deciview improvement, extinction, percentage of 
total extinction, and the percentage of the total impact from Texas 
point sources addressed by the control).
    Comment: We received comments on the method we used to adjust CAMx 
results. Commenters stated that we developed a linear relationship 
between emissions and extinction and then adjusted CAMx modeled 
extinction linearly with emissions to match proposed controlled 
emission levels. The commenters stated that the relationship between 
emissions and light extinction is not linear and that interactions 
between nitrate and sulfate create a complicated relationship. The 
commenters cited to the CAMx user guide which they claim supports that 
the relationship is non-linear. In contrast, Earthjustice said that our 
approach was reasonable.
    Response: We disagree with the comments that the methodology used 
to estimate visibility benefits from control level emissions was 
unjustified or unreasonable, and agree with Earthjustice that our 
approach was reasonable. The linear relationship we developed to 
extrapolate extinction due to controlled emission rates was a 
reasonable approach in our technical analysis.
    We agree with the commenters that, in general, the relationship 
between downwind concentrations and emissions can be complicated and 
non-linear due to complex chemistry, including the fact that reductions 
in sulfur emissions can result in an increase in ammonium nitrate. Each 
modeled emission scenario took this complex chemistry into account in 
estimating the visibility impacts for that scenario. We estimated 
control efficiencies for a high and low control case scenario that 
would span the range and give a reasonable approximation of emission 
reductions of potential controls and maximize the number of data points 
available to estimate the visibility benefit due to a reduction in 
emissions.\170\ Using the unit level High and Low modeled visibility 
impacts and the 2018 facility level modeling described in the FIP TSD, 
we examined the relationship between the various levels of emissions 
from a modeled site and the modeled visibility impact at each Class I 
area. For each facility and Class I area, the available modeled data 
were linear with high correlation and the modeled emission levels were 
relatively close to the estimated control levels examined. Therefore we 
used the linear fit to extrapolate the anticipated visibility impact/
benefit from a given level of emission/control.\171\ We agree that 
small perturbations relative to the model inputs can be approximated as 
linear. However, as discussed in more detail in our response to this 
comment in the RTC document, we disagree with the commenters that we 
extended the linear treatment to large variations, and we note errors 
in the commenters' assessment of the differences between modeled and 
required control levels. The variations between the modeled High 
control levels and the control levels required in the FIP are 
relatively small. This is a small perturbation from the modeled levels, 
a small difference in estimated extinction benefit from the modeled and 
required control level, and does not impact our overall decisions on 
the significance of visibility benefits from the required controls. We 
agree with Earthjustice that the small level of uncertainty in the 
visibility benefit from these controls introduced by the linear 
extrapolation does not impact the overall conclusions. In every case, 
the required control level emissions are the same or less than the high 
control level modeled, and the visibility benefits from controls at the 
required control level will be the same or more than those modeled at 
the high control level. Therefore, the high level modeled visibility 
benefits can be seen as a lower bound and even these support our 
decision.
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    \170\ See FIP TSD at A-54 for a more detailed description
    \171\ See the file, ``Vis modeling summary.xlsx'' in the docket 
for this action for our calculations and estimates of visibility 
benefits from the examined levels of controls.
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    Comment: We also received comments on the calculation of a deciview 
impact or improvement based on natural ``clean'' background conditions 
and the estimated visibility impacts/improvement based on recent actual 
emissions rather than projected 2018 emissions. The commenters contend 
that the use of natural background overstates the estimated visibility 
benefit from the proposed controls and that these adjustments based on 
recent actual emissions and natural background artificially increase 
projected visibility improvement from the proposed controls. The 
commenter states that the use of ``natural conditions'' is contrary to 
the regulations, inconsistent with agency precedent, and arbitrary and 
capricious and that the analysis does not address the relevant legal 
issue and is not rationally connected to the final decision (i.e. what 
is a reasonable progress goal for 2018).
    Response: We disagree with the commenter that the use of ``natural 
conditions'' is contrary to the regulations, inconsistent with agency 
precedent, and arbitrary and capricious. We disagree with the commenter 
that the analysis does not address the relevant legal issue and is not 
rationally connected to the final decision (i.e., as defined by the 
commenter as what is a reasonable progress goal for 2018). The Regional 
Haze Rule requires that we identify reasonable controls based on 
consideration of the four statutory factors and establish a reasonable 
progress goal that reflects the

[[Page 336]]

anticipated amount of visibility improvement from implementation of 
those controls in additional to all other ``on the books'' controls. 
Specifically, Sec.  51.308(d)(1)(i)(A) requires consideration of the 
four factors and a demonstration of how these factors were taken into 
consideration in selecting the visibility goal. We analyzed the time 
necessary for compliance, energy and non-air environmental impacts, the 
remaining useful life, and the costs of compliance including 
consideration of the anticipated visibility benefits of specific 
controls on individual units. As discussed in depth below, in 
considering the anticipated visibility benefits from individual 
controls, it was appropriate to consider estimated benefits on a 
``clean'' or ``natural'' background.
    In the FIP TSD, we discuss the need to estimate visibility benefits 
using both a ``clean'' and ``dirty'' background: \172\
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    \172\ See our FIP TSD, page A-39.

The deciview improvement based on the 2018 background conditions 
provides an estimate of the amount of benefit that can be 
anticipated in 2018 and the impact a control/emission reduction may 
have on the established RPG [reasonable progress goal] for 2018. 
However, this estimate based on degraded or ``dirty'' background 
conditions underestimates the visibility improvement that would be 
realized for the control options under consideration. Because of the 
non-linear nature of the deciview metric, as a Class I area becomes 
more polluted the visibility impairment from an individual source in 
terms of deciviews becomes geometrically less. Results based solely 
on a degraded background will rarely if ever demonstrate an 
appreciable effect on incremental visibility improvement in a given 
area. Rather than providing for incremental improvements towards the 
goal of natural visibility, degraded background results will serve 
to instead maintain those current degraded conditions. Therefore, 
the visibility benefit estimated based on natural or ``clean'' 
conditions is needed to assess the full benefit from potential 
---------------------------------------------------------------------------
controls.

    In considering the visibility benefits of potential controls, we 
considered deciview improvements as well as the reduction in extinction 
and percent extinction. By definition, the ``clean'' background 
analysis using natural conditions eliminates the impact from all other 
anthropogenic sources, domestic and international. This approach is 
aimed at assessing the full potential visibility benefit of controls. 
It is not reasonable to only assess the visibility benefit of controls, 
the value of installing a control in the immediate future that will 
permanently reduce visibility impacts from a source, in such a manner 
that is dependent on the current level of emissions or impact from 
other sources or other countries. For example, in considering only the 
estimated visibility benefit from controlling Big Brown using a 
``dirty'' background, an increase in visibility impacts from Mexico 
emissions or emissions from another Texas point source would result in 
a decrease in the visibility benefit in deciviews from installing 
controls on Big Brown, making controls appear less beneficial. By using 
a metric that is independent of all other emission sources (``clean''), 
we avoid this paradox that the dirtier the existing air, the less 
likely it would be that any control is required. This was also 
explained in the preamble to the final Regional Haze Rule and 
Guidelines for BART Determinations.\173\ The use of ``clean'' 
background is necessary to assess the full potential benefit from 
controls and does not overstate the visibility benefit.
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    \173\ Using existing conditions as the baseline for single 
source visibility impact determinations would create the following 
paradox: The dirtier the existing air, the less likely it would be 
that any control is required. This is true because of the nonlinear 
nature of visibility impairment. In other words, as a Class I area 
becomes more polluted, any individual source's contribution to 
changes in impairment becomes geometrically less. Therefore the more 
polluted the Class I area would become, the less control would seem 
to be needed from an individual source. We agree that this kind of 
calculation would essentially raise the ``cause or contribute'' 
applicability threshold to a level that would never allow enough 
emission control to significantly improve visibility. Such a reading 
would render the visibility provisions meaningless, as EPA and the 
States would be prevented from assuring ``reasonable progress'' and 
fulfilling the statutorily-defined goals of the visibility program. 
Conversely, measuring improvement against clean conditions would 
ensure reasonable progress toward those clean conditions. 70 FR 
39124.
---------------------------------------------------------------------------

    Our use of ``clean'' background is also consistent with the 
methodology used by Texas for BART visibility analysis, which also 
relied on CAMx photochemical modeling with source apportionment. The 
TCEQ utilized this approach in assessing the visibility impacts from 
individual sources and groups of sources to determine their 
significance for BART screening. As detailed in the screening analysis 
protocol developed by TCEQ and reviewed by us, ``The source's HI [haze 
index] is compared to natural conditions to assess the significance of 
the source's visibility impact. EPA guidance lists natural conditions 
(bnatural) by Class I area in terms of Mm-\1\ 
(EPA, 2003b) and assumes clean conditions with no anthropogenic or 
weather interference. The visibility significance metric for evaluating 
BART sources is the change in deciview (del-dv) from the source's and 
natural conditions haze indices.'' \174\
---------------------------------------------------------------------------

    \174\ Texas Regional Haze SIP, Appendix 9-5, ``Screening 
Analysis of Potential BART-Eligible Sources in Texas'' at 2-11, 
emphasis added.
---------------------------------------------------------------------------

    We disagree with the commenter that our use of the ``natural 
background'' metric is contrary to regulations. As we discuss in a 
separate response to comment concerning the legality of the extinction 
and percent extinction metrics, the commenter fails to distinguish 
between the required metric used to describe overall visibility 
conditions at a Class I area at a given point in time and the range of 
metrics that can be used to describe the visibility impairment due to 
an individual source, group of sources, a state's sources, or some 
other portion of the visibility impairment at a Class I area. As 
explained above, it is necessary to consider the visibility benefit of 
controls on a ``clean'' background basis to assess the full benefit 
from potential controls.
    The use of natural background is also supported by our previous 
action on North Dakota's regional haze SIP and the associated Eighth 
Circuit Court decision. The full text of our determination in North 
Dakota is: \175\
---------------------------------------------------------------------------

    \175\ 76 FR 58627.

    In addition to evaluating the four statutory factors, North 
Dakota also considered the visibility impacts associated with the 
control options for each RP source. However, in modeling visibility 
impacts, North Dakota used a hybrid cumulative modeling approach 
that is inappropriate for determining the visibility impact for 
individual sources. As with the modeling North Dakota conducted for 
its NOX BART analysis for MRYS [Milton R. Young Station] 
Units 1 and 2 and LOS [Leland Olds Station] Unit 2, the approach 
fails to compare single- source impacts to natural background. While 
there is no requirement that States, when performing RP analyses, 
follow the modeling procedures set out in the BART guidelines, or 
that they consider visibility impacts at all, we find that North 
Dakota's visibility modeling significantly understates the 
visibility improvement that would be realized for the control 
options under consideration. Accordingly, we are disregarding the 
modeling analysis that North Dakota has used to support its RP 
---------------------------------------------------------------------------
determinations for individual sources.

    The Eighth Circuit Court's decision affirmed our position that the 
use of degraded, or dirty background, was not consistent with the CAA. 
The relevant section of the 8th Circuit Court's decision on this point 
reads: \176\
---------------------------------------------------------------------------

    \176\ North Dakota v. EPA, 730 F.3d 750, 766 (8th Cir. 2013).

Although the State was free to employ its own visibility model and 
to consider visibility improvement in its RP

[[Page 337]]

determinations, it was not free to do so in a manner that was 
inconsistent with the CAA. Because the goal of section 169A is to 
attain natural visibility conditions in mandatory Class I Federal 
areas, see 42 U.S.C. 7491(a)(1), and EPA has demonstrated that the 
visibility model used by the State would serve instead to maintain 
current degraded conditions, we cannot say that EPA acted in a 
manner that was arbitrary, capricious, or an abuse of discretion by 
disapproving the State's RP determination based upon its cumulative 
---------------------------------------------------------------------------
source visibility modeling.

    The use of natural background conditions to assess visibility 
benefits of individual controls, as we have done here in this action, 
is consistent with the goals of the CAA. As to the comment that we 
adjusted the modeled results by updating the baseline uncontrolled 
emissions for each unit based on SO2 emissions data for 
2009-2013, this was a necessary step to assess the visibility benefit 
of controls relative to the visibility impairment due to future 
anticipated emission levels at these units without the required 
controls. Comparison of 2018 CENRAP projected emissions to recent 
actual emissions showed that a number of facilities have actual 
emissions that are much higher than CENRAP 2018 modeled emissions.\177\ 
For instance, Big Brown, Sandow, and Martin Lake actual emissions were 
all significantly higher than 2018 CENRAP modeled rates, with Martin 
Lake having over 90% more SO2 emissions than projected by 
CENRAP for 2018. Both Pirkey and Oklaunion had much smaller actual 
SO2 emissions than projected. As we discuss in the FIP TSD, 
we believe that recent actual emissions are more representative of 
anticipated future emissions at the sources evaluated than the CAIR 
projections developed in 2006 and adopted by CENRAP. The CENRAP 
modeling was based on an IPM (Integrated Planning Model) that estimated 
EGU future emissions in 2018 including reductions for CAIR across the 
eastern half of the United States. This analysis was conducted in 2006 
and projected that Texas would be a purchaser of SO2 
credits, and that not much high level control would be placed on Texas 
EGU sources. Given the length of time between 2006 when the IPM 
analysis was conducted, and 2013 when we were conducting this analysis, 
we had some concern that these projections could be off for the EGUs in 
Texas. Information available also indicates that SO2 credits 
are much cheaper than originally projected, therefore more credits may 
have been used in lieu of emission reductions. We also weighed the 
technique that Texas has used in estimating emissions from EGUs for 
future years (including 2018) in ozone attainment demonstration SIPs in 
DFW and HGB. For these photochemical modeling analyses with CAMx, Texas 
has relied upon the recent CEM data that is also included in CAMD's 
databases in conjunction with information on recently permitted EGUs 
for estimating the emissions to model for EGUs in Texas in 2018 as 
these overall EGU emission levels are already near levels projected 
under CAIR Phase II control such that further emission reductions are 
doubtful in the absence of some new requirements.
---------------------------------------------------------------------------

    \177\ See Table A.4-2 of the FIP TSD for a comparison of recent 
actual emissions to CENRAP 2018 projected emission levels.
---------------------------------------------------------------------------

    The actual SO2 allowances for Texas under CSAPR are not 
much different than the CAIR Cap for Texas, so large additional 
reductions over current emission levels were not expected. However, 
because we had earlier projected with IPM that controls for MATS may 
generate the installation of additional scrubbers in Texas that could 
potentially result in further SO2 reductions, we again 
investigated this possibility. Texas recently submitted comments to us 
on a more recent IPM projection that was at the time intended by EPA to 
be part of a new modeling platform for national rule making.\178\ In 
these comments and comments from several EGU owners in Texas, the 
assertion was that no significant amount of additional SO2 
controls are expected due to compliance with MATS. The comments also 
pointed out that, as some of our cursory research had also indicated, 
no large SO2 control projects were planned at most of the 
sources we were evaluating. Therefore, based on Texas' recent comments 
and other information, we concluded considerable uncertainty exists as 
to whether any further reductions of SO2 will occur beyond 
current emission levels as a result of compliance with MATS or CSAPR. 
Overall this information supports looking at recent actual emissions to 
represent future emission levels in 2018.
---------------------------------------------------------------------------

    \178\ TCEQ comment letter to EPA on draft modeling platform 
dated June 24, 2014. `2018 EMP signed.pdf'.
---------------------------------------------------------------------------

    In summary, this adjustment from CENRAP 2018 to the baseline 
calculated from recent actual emissions was not an ``artificial 
adjustment'' and was necessary to account for the large difference 
between specific unit-level emissions in the 2018 CENRAP emissions and 
a baseline more representative of anticipated future emission levels in 
2018. We estimated and presented the estimated visibility benefit of 
controls based on both the CENRAP 2018 projected emission levels and 
emission levels consistent with recent actual emissions data. The 
results considering the 2018 CENRAP emissions baseline were also needed 
to provide a comparison with the Texas regional haze SIP and an 
estimate of the change from the 2018 CENRAP modeled reasonable progress 
goal to a new reasonable progress goal including the controls required 
in the FIP. The visibility benefit of individual controls calculated 
based on the CENRAP 2018 emissions baseline represents the additional 
level of visibility benefit from controlling individual units, 
consistent with the assumptions/emission projections in the Texas 
regional haze SIP.
    Comment: EPA's methodology to estimate revised reasonable progress 
goals for Big Bend, the Guadalupe Mountains, and the Wichita Mountains 
is without precedent and is not supported by the record. The commenters 
also state that the revised reasonable progress goals are incorrect 
because they do not account for reductions in Oklahoma emissions.
    Response: We disagree with the comment and believe we took a 
reasonable approach to estimate the change in overall visibility 
impairment anticipated due to the required controls and provided all 
calculations for review. We also disagree with the commenter's 
description of how the states estimated the reasonable progress goals. 
While our guidance suggests that reasonable progress goals should be 
established by modeling all existing and reasonable controls, in 
practice all RPOs including CENRAP completed the modeling early in the 
process. The 2018 CENRAP modeling was completed before any states had 
completed their BART and reasonable progress determinations. In many 
cases, the 2018 projection included an assumption of BART level 
controls and ``on the book'' controls. Once final BART determinations 
and reasonable progress determinations were completed, the RPO did not 
go back and remodel to reassess the reasonable progress goals. In our 
proposed action in Arkansas,\179\ as well as our actions in Arizona 
\180\ and Hawaii,\181\ the modeled reasonable progress goals were 
adjusted based on a methodology of scaling of visibility extinction 
components in proportion to emission changes. We noted that although we 
recognize that this method is not refined, it allows us to translate

[[Page 338]]

the emission reductions achieved through the FIP into quantitative 
reasonable progress goals, based on modeling previously performed by 
the RPOs. However, in this case, our analysis using CAMx modeling and 
source apportionment, provided a somewhat more refined means to 
estimate the visibility benefit from specific individual controls on 
the 20% worst days in 2018. While there is limited precedent for 
adjusting the RPO calculated reasonable progress goals to account for 
emission reductions achieved in a FIP or revised SIP, we took a 
reasonable approach based on the information available. We adjusted 
each reasonable progress goal established by Texas or Oklahoma for 2018 
by the amount of visibility benefit anticipated from all scrubber 
upgrades estimated by our modeling analysis based on CAMx source 
apportionment modeling.\182\ In estimating the deciview visibility 
benefit in 2018 compared to the CENRAP modeled 2018 reasonable progress 
goals, we considered reductions from 2018 CENRAP emissions levels and 
2018 ``dirty'' background conditions. We believe that this is a 
reliable estimate of the amount of visibility benefit anticipated from 
controls (e.g., 0.14 dv for the Wichita Mountains) beyond the projected 
2018 CENRAP reasonable progress goals. We then simply adjusted the 
reasonable progress goals established by the state by the amount of 
visibility benefit anticipated from the additional controls.
---------------------------------------------------------------------------

    \179\ 80 FR 18944, 18997.
    \180\ 79 FR 52420, 52468.
    \181\ 77 FR 31692, 31708.
    \182\ As discussed elsewhere in this document, while the 
required scrubber retrofits will provide for additional visibility 
improvement at the Class I areas that we consider necessary for 
reasonable progress towards natural visibility conditions, we do not 
anticipate these controls to be implemented until after 2018.
---------------------------------------------------------------------------

    As discussed above, we adjusted the CENRAP modeled reasonable 
progress goals to translate the emission reductions required in this 
FIP for Texas sources into quantitative reasonable progress goals. We 
note that the CENRAP modeling included an assumption for anticipated 
BART reductions for Oklahoma sources. We considered the comment 
concerning consideration of the reductions required by the BART FIP in 
Oklahoma in setting the 2018 reasonable progress goals and we believe 
these assumptions are a reasonable approximation of the anticipated 
BART reductions in Oklahoma at this time, considering the uncertainty 
of the timing of the reductions for some of the sources and the 
uncertainty in the final control scenario chosen by the operator to 
meet the requirements. The required enforceable emission limits in the 
Oklahoma and Texas FIPs remedy the deficiencies in the SIPs and our 
finalized reasonable progress goals properly consider the visibility 
benefits anticipated by those required emission reductions.
    Unlike the emission limits that apply to specific reasonable 
progress sources, the reasonable progress goals are not directly 
enforceable. Rather, the reasonable progress goals are an analytical 
tool used by EPA and the states to estimate future visibility 
conditions and track progress towards the goal of natural visibility 
conditions.
    Comment: EPA's proposal provides no basis for disapproving Texas' 
and Oklahoma's reasonable progress goals for the 20% best days and 
fails to provides analysis of the part of the reasonable progress goals 
addressing the ``best'' days.
    Response: We disagree with the comment. Our basis for disapproving 
the relevant reasonable progress goals for the 20% best days arises, as 
was noted in our proposal, from our determination that the analysis 
developed by Texas to evaluate reasonable progress controls was flawed 
and additional controls are necessary for the first planning period. 
Finalizing requirements for additional controls, as we now accomplish 
with our final rule, makes ``visibility on these days better than Texas 
projects,'' as we noted in our proposal.183 184 The 
submitted reasonable progress goals for the 20% best days did not 
consider reductions from the reasonable controls, so they cannot be 
approved. We understand the comment to request a quantitative 
assessment of the projected visibility conditions for the 20% best 
days. These calculations have been completed and add to our position 
that visibility will be better than Texas projects. These numbers, 
following the same methodology that we employed with the 20% worst 
days, are summarized in the table provided in the introduction section 
of the document.
---------------------------------------------------------------------------

    \183\ 79 FR 74843.
    \184\ ``No degradation,'' as distinctly needed for the 20% best 
days, is ensured because added controls do not significantly impact 
the 20% best days and would serve only to improve visibility on 
these days. Even so, what we provide as the 20% best day reasonable 
progress goals for 2018 (i.e., the ``least impaired days'') for Big 
Bend, Guadalupe Mountains and Wichita Mountains numerically differ 
from the numbers that Texas had submitted by very small amounts. By 
the design of 40 CFR 51.308(d)(1), improvements for the most 
impaired days provide a more vital benchmark for progress that may 
be made.
---------------------------------------------------------------------------

P. Interstate Visibility Transport

    We received comments opposing our proposed disapproval of the 
visibility protection portion of the interstate transport requirements 
in Texas infrastructure SIP submittals for the ozone, PM2.5, 
NO2, and SO2 NAAQS (CAA 110(a)(2)(D)(i)(II)). 
Among the adverse comments were the following: The requirements for 
infrastructure SIPs in CAA section 110(a)(2)(D)(i)(II) only contain 
structural, rather than substantive, requirements. Disapproving Texas' 
infrastructure SIPs conflicts with the differing deadlines for NAAQS 
SIP submittals and regional haze SIP submittals. Texas submitted 
separate SIPs to address the visibility prong of interstate transport 
for the 1997 ozone, the 2006 PM2.5, the 2008 ozone, the 2010 
SO2, and the 2010 NO2 standards and EPA failed to 
evaluate these submittals in its proposed disapproval. CAA section 
110(a)(2)(D)(i)(II) is pollutant specific, and, because EPA finds that 
Texas' SIP is inadequate to protect visibility only because it does not 
contain certain limitations on SO2 emissions, EPA should not 
disapprove for the other NAAQS at issue. The CAA's visibility 
protection requirement is narrower than the requirement for reasonable 
progress and requires only provisions necessary to prevent interference 
with control measures included in another state's plan to achieve a 
visibility standard. The CAA limits EPA's authority to require one 
state to adopt binding emission limits for the benefit of another 
state, citing EME Homer City.
    We disagree with the comments for several reasons. Section 
110(a)(2) specifies the substantive elements that infrastructure SIP 
submissions need to address, as appropriate, for EPA approval.\185\ EPA 
has disapproved portions of such SIPs for failure to comply with the 
interstate visibility transport requirements section 
110(a)(2)(D)(i)(II) for various other states. See 78 FR 46142, July 30, 
2013 (Arizona); 77 FR 14604, March 12, 2012 (Arkansas); 76 FR 52388, 
August 22, 2011 (New Mexico); 76 FR 81728, December 28, 2011 
(Oklahoma). By contrast, in many other SIP actions across the country, 
we have allowed states to rely on their approved regional haze plan to 
meet the substantive requirements of the visibility component of 
section 110(a)(2)(D)(i)(II) because the regional haze plan achieved at 
least as much emissions reductions as projected by the RPO modeling. 
See 76

[[Page 339]]

FR 34608, June 14, 2011 (California); 79 FR 60985, October 9, 2014 (New 
Mexico); 76 FR 36329, June 22, 2011 (Idaho); and 76 FR 38997, July 5, 
2011 (Oregon). We gave limited disapproval to the Texas regional haze 
SIP based on its reliance on CAIR. CAIR provided limits on emissions of 
SO2 and NOX. SO2 is a precursor for 
PM2.5. NOX is a precursor for ozone and for 
PM2.5. NO2 is a component of NOX. With 
CAIR no longer in effect, Texas may not rely on its regional haze SIP 
to ensure that emissions from Texas do not interfere with measures to 
protect visibility in nearby states. We recognize that CAA section 
110(a)(2)(D)(i)(II) is pollutant specific; nevertheless, ozone, 
PM2.5, NO2, and SO2 or their 
precursors could interfere with visibility protection. Because Texas 
has not demonstrated that its SIP submittals ensure that Texas 
emissions would not interfere with measures required to be included in 
the SIP for any other state to protect visibility, we are disapproving 
these SIP submittals.
---------------------------------------------------------------------------

    \185\ See September 13, 2013 EPA guidance memo ``Guidance on 
Infrastructure State Implementation Plan (SIP) Elements under Clean 
Air Act Sections 110(a)(1) and 110(a)(2)'', http://www3.epa.gov/airquality/urbanair/sipstatus/docs/Guidance_on_Infrastructure_SIP_Elements_Multipollutant_FINAL_Sept_2013.pdf.
---------------------------------------------------------------------------

    As discussed in this action, the D.C. Circuit Court in EME Homer 
City recently issued a decision upholding CSAPR but remanding without 
vacating a number of the Rule's state emissions budgets, including 
those for Texas. The CSAPR remand did not affect our reasons for 
proposing to disapprove portions of Texas' SIP submittals that address 
CAA provisions for prohibiting air pollutant emissions from interfering 
with measures required to protect visibility in any other state for the 
1997 PM2.5, 2006 PM2.5, 1997 ozone, 2008 ozone, 
2010 NO2, and 2010 SO2 NAAQS. However, the remand 
did affect our proposal to rely on CSAPR to help address our FIP 
obligation for interstate transport of air pollution and visibility 
protection. Therefore, today's action does not finalize the portion of 
our proposed FIP that would have relied on CSAPR to satisfy Texas' 
visibility transport obligations with respect to the aforementioned 
NAAQS. We will address the visibility transport requirements for Texas 
in a future rulemaking once the issues surrounding the partial remand 
are resolved.

Q. Disapproval of the Oklahoma and Texas Reasonable Progress Goals

    We received numerous comments on our proposed disapproval of the 
reasonable progress goals selected by Texas and Oklahoma for their 
respective Class I areas and the recalculated reasonable progress goals 
we proposed. Some comments were in support of our proposed disapproval 
of the state's reasonable progress goals and our proposed recalculated 
reasonable progress goals. However, a majority of the comments raised 
objections to our proposed action on the reasonable progress goals. 
These commenters raised numerous issues in support of their objections 
to our proposal, including that recent monitoring data from IMPROVE 
monitors indicates the Class I areas are already meeting the new 
reasonable progress goals we proposed without the need for the 
additional controls we proposed, that there have been significant 
SO2 and NOX emissions reductions in Texas since 
the baseline period, that our proposed disapproval of the state's 
reasonable progress goals had no technical or legal basis, and that we 
inappropriately recalculated the new reasonable progress goals we 
proposed.
    Below we present a summary of our responses to the more significant 
comments we received that relate to our proposed action on the 
reasonable progress goals for Texas and Oklahoma Class I areas. See our 
RTC document for a more in-depth presentation of the comments we 
received and our responses to them.
    Comment: Our proposed disapproval of Oklahoma's reasonable progress 
goals for the Wichita Mountains is proper and required by the CAA, as 
the record is clear that control measures satisfying the four 
reasonable progress factors are available for some of the largest 
sources of visibility impairment at the Wichita Mountains. Our proposed 
finding that Oklahoma and Texas did not adequately consult with each 
other regarding the impact of Texas sources on Oklahoma's Class I area 
is also proper because in order to engage in meaningful consultation, 
an upwind state such as Texas must provide impacted states with 
sufficient technical information detailing the visibility impacts of 
individual sources and the feasibility and cost-effectiveness of 
control measures on those sources. A downwind state such as Oklahoma 
should request the adequate information when it is not provided by the 
upwind state and must take a hard look at this information and request 
that upwind states require the control measures that satisfy the four 
factors laid out in the statute for making reasonable progress. We 
support the EPA's conclusions as to what constitutes a proper and 
meaningful consultation under the regional haze program and support the 
EPA's proposed disapproval of Oklahoma's reasonable progress goals and 
finding that the consultations between Oklahoma and Texas were 
inadequate.
    Response: We appreciate the commenter's support of our 
interpretation of what constitutes an adequate consultation that 
satisfies the Regional Haze Rule requirements. We also appreciate the 
commenter's support of our proposed disapproval of Oklahoma's 
reasonable progress goals for the Wichita Mountains and our finding 
that the consultations between Oklahoma and Texas to address the 
impacts of Texas sources on the Wichita Mountains were not adequate and 
did not meet the regional haze requirements. We are finalizing as 
proposed our disapproval of several of the requirements with regard to 
Oklahoma's establishing of reasonable progress goals for the Wichita 
Mountains, including our finding that the consultations between Texas 
and Oklahoma to address Texas' impacts on the Wichita Mountains were 
not adequate and did not meet the Regional Haze Rule requirements.
    Comment: EPA should withdraw its proposed FIP and instead fully 
approve the regional haze SIPs submitted by Texas and Oklahoma because 
the SIP submitted by Texas fully complies with the statute and all 
regulatory standards and therefore there is no legal or technical basis 
for EPA's proposed FIP. On every level, EPA's proposal exceeds the 
agency's authority under the CAA and EPA's regional haze regulations.
    Response: We disagree with the commenter that there is no legal or 
technical basis for our proposed FIP, that the proposed FIP exceeds our 
authority under the CAA and the regional haze regulations, and that the 
SIP submitted by Texas fully complies with the statute and regulatory 
requirements. The CAA and Sec.  51.308(d)(1) provide how to determine 
what constitutes reasonable progress for each planning period and 
specify the requirements related to establishment of the reasonable 
progress goals for each Class I area. In particular, both the CAA and 
the Regional Haze Rule require states to consider four factors when 
setting reasonable progress goals: The costs of compliance, time 
necessary for compliance, energy and non-air quality environmental 
impacts, and the remaining useful life of potentially affected 
sources.\186\ The Regional Haze Rule also requires that in establishing 
the reasonable progress goals, states must consider the uniform rate of 
progress and the emission reduction measures needed to achieve it for 
the period covered by the implementation plan. In addition, because the 
reasonable progress goals selected by Texas and Oklahoma provide for a 
rate of improvement slower than the

[[Page 340]]

uniform rate of progress, the Regional Haze Rule requires the states to 
demonstrate why their reasonable progress goals are reasonable and why 
a rate of progress leading to natural visibility conditions by 2064 is 
not reasonable.\187\ As discussed in more detail in our proposal and in 
the RTC document associated with this final action, Texas did not 
satisfy several of the requirements at Sec.  51.308(d)(1) with regard 
to setting reasonable progress goals for its own Class I areas, most 
notably the requirement to reasonably consider the four statutory 
reasonable progress factors and the requirement to adequately consider 
the emission reduction measures needed to meet the uniform rate of 
progress. Texas also did not satisfy the consultation requirements at 
Sec.  51.308(d)(3)(i) to address its impacts on the Wichita Mountains. 
Oklahoma also did not satisfy certain requirements under Sec.  
51.308(d)(1) with regard to setting reasonable progress goals for the 
Wichita Mountains, including the requirement to adequately consult with 
other states that may reasonably be anticipated to cause or contribute 
to visibility impairment at the Wichita Mountains and the requirement 
to adequately consider the emission reduction measures needed to meet 
the uniform rate of progress. Therefore, we disagree that the Texas and 
Oklahoma SIPs fully comply with the statutory and regulatory 
requirements and that our FIP exceeds our authority under the CAA. We 
are finalizing our proposed disapproval of Texas' and Oklahoma's 
reasonable progress goals and the controls we proposed under reasonable 
progress for sources in Texas.
---------------------------------------------------------------------------

    \186\ CAA Section 169A(g)(1), 42 U.S.C. 7491(g)(1). 40 CFR 
51.308(d)(1)(i)(A).
    \187\ 40 CFR 51.308(d)(1)(ii).
---------------------------------------------------------------------------

    Comment: EPA does not take issue with Oklahoma's four-factor 
analysis, but nevertheless proposes to reset Oklahoma's reasonable 
progress goals based on its reasonable progress analysis for Texas 
sources. EPA also finds it necessary to disapprove Oklahoma's 
reasonable progress goals because they did not include the emission 
reductions from the Oklahoma SO2 BART FIP and the revised 
BART SIP for the AEP units that were subsequently promulgated. However, 
EPA's proposed SIP does not correct this error either.
    Response: The comment that we disapproved the reasonable progress 
goals for the Wichita Mountains because they do not include the 
emission reductions from the SO2 BART FIP and the revised 
BART SIP for the AEP units that have subsequently been promulgated is 
taken out of context and does not fully capture the rationale for our 
disapproval. We are disapproving the reasonable progress goals for the 
Wichita Mountains because they do not account for emission reductions 
from reasonable measures at Texas sources. We stated in the proposal 
that the reasonable progress goals selected by Oklahoma for the Wichita 
Mountains do not include the level of reductions necessary to meet the 
requirements under 40 CFR 51.308(e) for BART. We further explain that 
``BART is a component of developing the reasonable progress goals, and 
the reasonable progress goals are inadequate because BART controls were 
not adequately considered. We note this deficiency is addressed by our 
Oklahoma BART FIP and the revised Oklahoma BART SIP.'' \188\ The 
visibility modeling developed for CENRAP and used by Oklahoma in 
support of its SIP revision submittal assumed SO2 reductions 
from the six BART sources that Oklahoma subsequently did not secure 
when making its BART determinations for these sources. We believe that 
the BART limits in our Oklahoma BART FIP \189\ have adequately 
addressed the deficiency. We also provide in our proposal additional 
reasons for disapproving the reasonable progress goals, stating 
``Oklahoma's consultations with Texas were flawed, which prevented 
Oklahoma from adequately developing its reasonable progress goals for 
the Wichita Mountains,'' and, because Oklahoma's consultations with 
Texas were flawed, Oklahoma did not adequately demonstrate that the 
reasonable progress goals it established were reasonable based on the 
four statutory factors under Sec.  51.308(d)(1)(ii).\190\ Comments 
regarding how we calculated the reasonable progress goals for the 
Wichita Mountains, Big Bend, or the Guadalupe Mountains, and our 
consideration of emission reductions from BART requirements in Oklahoma 
are addressed in a separate response to comment.
---------------------------------------------------------------------------

    \188\ 79 FR 74871, 74872.
    \189\ 76 FR 81728.
    \190\ 79 FR 74872.
---------------------------------------------------------------------------

    Comment: EPA's proposed disapproval of Texas' reasonable progress 
goals and its substitution with new reasonable progress goals in the 
proposed FIP is based on EPA's flawed interpretation of what the CAA 
requires for ``reasonable progress goals.'' This action is based on the 
EPA's conclusion that ``reasonable progress'' must be determined based 
on source-specific cost of controls even though such a requirement did 
not exist in the statute, the Regional Haze Rule, or the guidance 
available in 2009. The Texas 2009 regional haze SIP established 
reasonable progress goals for both Big Bend and the Guadalupe Mountains 
that provide for visibility improvement for the most impaired days over 
the period of the SIP and ensure no degradation in visibility for the 
least impaired days over the same period. The EPA agrees the SIP meets 
these requirements and also agrees that the TCEQ considered the four 
statutory factors in establishing the reasonable progress goals for its 
Class I areas in accordance with the Regional Haze Rule. Furthermore, 
the four statutory factors in and of themselves do not determine the 
reasonableness of the goals for the planning period. The Regional Haze 
Rule, in 40 CFR 51.308(d)(1)(iii), requires the EPA to evaluate whether 
the state's goal for visibility improvement provides for reasonable 
progress based on a demonstration of which the four statutory factors 
are only one element. Therefore, EPA's proposed disapproval of Texas' 
reasonable progress goals and its proposed new reasonable progress 
goals is flawed.
    Response: We disagree that our proposed disapproval of Texas' 
reasonable progress goals is based on a flawed interpretation of what 
the CAA requires for reasonable progress goals. As we discuss in our 
responses to other similar comments, we believe that our evaluation of 
cost, including visibility benefits, on a source-specific basis was an 
appropriate and reasonable interpretation of the analysis required in 
this instance, in order to determine what, if any, level of control for 
Texas sources constituted reasonable progress for this planning period.
    We agree that Sec.  51.308(d)(1) requires more than just the 
consideration of the four factors in the establishment of the 
reasonable progress goals. Also, although we agree Texas conducted an 
evaluation of the four reasonable progress factors, we determined that 
that evaluation was flawed. Texas did not fully satisfy the 
requirements under Sec.  51.308(d)(1) related to the evaluation of the 
four reasonable progress factors and establishment of the reasonable 
progress goals for the two Texas Class I areas. We note that Sec.  
51.308(d)(1)(iii) provides that in determining whether the State's goal 
for visibility improvement provides for reasonable progress towards 
natural visibility conditions, the Administrator will evaluate the 
demonstrations developed by the State pursuant to paragraphs (d)(1)(i) 
and (ii). Thus, we are specifically directed to judge the quality of a 
state's submission of these key parts

[[Page 341]]

of its reasonable progress goals development, which we found to be 
flawed. In particular, as we discussed in detail in our proposal, we 
disagree with the set of potential controls identified by Texas and how 
it analyzed and weighed the four reasonable progress factors under 
Sec.  51.308(d)(1)(i)(A) \191\ and we further proposed to disapprove 
Texas' reasonable progress goals under Sec.  51.308(d)(1)(ii).\192\ For 
the reasons given in the proposal and affirmed in this final action, we 
cannot approve Texas' reasonable progress goals. In this action, we are 
finalizing our disapproval of Texas' reasonable progress goals for Big 
Bend and the Guadalupe Mountains and we are establishing new reasonable 
progress goals for these Class I areas, as discussed in our proposal.
---------------------------------------------------------------------------

    \191\ 79 FR 74838.
    \192\ 79 FR 74843.
---------------------------------------------------------------------------

    Comment: EPA fails to take into consideration the TCEQ's 2014 Five-
Year Regional Haze SIP Revision or the effects of early action or 
emission reduction accomplished or to be accomplished by other EPA 
programs before imposing additional requirements beyond the state 
submitted SIPs. Considering that the visibility improvements of these 
programs have not yet been quantified, and the gradual progress 
anticipated in establishing such a long-term goal, EPA should be 
patient and not take such aggressive action in overriding reasonable 
state SIPs and imposing additional controls.
    Response: We stated in our proposal that the TCEQ submitted the 
first five-year report in March 2014, but we are not including our 
analysis of that SIP revision within this action.\193\ The five-year 
progress report is a requirement that is separate from the regional 
haze SIP required for the first planning period, and it has separate 
content and criteria for us to review. We therefore believe we are not 
obligated to consider or take action on the five-year progress report 
at the same time we take action on the regional haze SIP for the first 
planning period. Even so, we acknowledge that recent monitoring data 
from IMPROVE monitors indicate that the more recent five-year average 
measurements of visibility extinction at Texas and Oklahoma Class I 
areas on the 20% worst days contained in the progress report are lower 
(i.e., indicate better visibility conditions) than the numerical 
reasonable progress goals we are establishing for these Class I areas. 
This issue is addressed in detail elsewhere in this final action and in 
the RTC document.
---------------------------------------------------------------------------

    \193\ 79 FR 74864.
---------------------------------------------------------------------------

    We disagree with the commenter's contention that we should not 
impose additional controls on Texas sources and instead approve the 
Texas regional haze SIP and the remaining portion of the Oklahoma 
regional haze SIP because there may be potential visibility 
improvements that have not yet been quantified, resulting from early 
actions and emission reductions accomplished or expected to be 
accomplished through other EPA programs. If it is determined based on 
the demonstrations developed pursuant to Sec.  51.308(d)(1)(i) and (ii) 
that there are reasonable and cost-effective controls available that 
would provide for reasonable progress, the statute and regional haze 
regulations do not allow for a delay in requiring these controls to 
allow time for the quantification and consideration of possible future 
visibility improvements. Therefore, we are finalizing our proposed 
disapproval of Texas' and Oklahoma's reasonable progress goals and are 
finalizing the control requirements we proposed for Texas sources under 
the reasonable progress and long-term strategy reasonable progress 
requirements.
    Comment: The regional haze program tasks states with determining 
what is reasonable progress toward elimination of man-made visibility 
impairment, along with specific progress milestones (10-year planning 
and SIP revisions, with program reviews in the middle of the 10-year 
planning periods). The regional haze program contemplates gradual 
visibility improvements along a ``glide path'' that considers the 2064 
goal, and does not require immediate reductions that exceed 
``reasonable progress'' as determined by the state based on the four 
statutory factors. Thus, it neither requires nor authorizes the 
frontloading of extensive control requirements.
    Response: The commenter's contention concerning reasonable progress 
is premised on the assumption that the emissions reductions that are 
part of the state's long-term strategy and upon which its reasonable 
progress goals are based do in fact constitute reasonable progress. The 
determination of what constitutes reasonable progress must be made 
pursuant to Sec.  51.308(d)(1). Based on its analyses under Sec.  
51.308(d)(1), a state (or EPA in the context of a FIP) may determine 
that a greater or lesser amount of visibility improvement than what is 
needed to get on the glide path is what constitutes reasonable 
progress.\194\ As discussed in our proposal and within this action, we 
disagree with the set of potential controls identified by the TCEQ as 
having the greatest impact on visibility on the three Class I areas and 
how it analyzed and weighed the four reasonable progress factors in a 
number of key areas.\195\ Therefore, we proposed to disapprove Texas' 
reasonable progress goals for its Class I areas and conducted our own 
analysis of the four reasonable progress factors to fill in the 
regulatory gap that would be created by our disapproval action. We are 
replacing Texas' flawed reasonable progress analysis with our own and 
are finalizing the cost-effective reasonable progress controls we 
proposed on the small number of Texas point sources that have the 
greatest visibility impacts on the Class I areas of interest.
---------------------------------------------------------------------------

    \194\ 64 FR 35732.
    \195\ 79 FR 74838.
---------------------------------------------------------------------------

    Comment: Texas' four-factor analysis and its reasonable progress 
goals were reasonable and within the state's broad discretion, and are 
supported by recent monitoring data showing the reasonable progress 
goals will be met for Oklahoma and Texas Class I areas without the 
additional controls EPA proposed for Texas sources. The most recent 
five-year (2009-2013) averages of visibility monitoring data from 
IMPROVE monitors indicates that visibility impairment at the Guadalupe 
Mountains, Big Bend, and the Wichita Mountains, are lower than both the 
2018 reasonable progress goals proposed by the states and the more 
stringent 2018 reasonable progress goals proposed by EPA. The Texas 
five-year regional haze progress report issued in 2014 includes a 
projection of further reductions of haze-forming SO2 and 
NOX emissions from point sources through 2018. Therefore, 
the commenter concludes that it is expected that visibility 
improvements observed through 2013 for Big Bend, the Guadalupe 
Mountains, and the Wichita Mountains will continue and that the 2018 
reasonable progress goals that EPA proposes will be met without the 
further emission controls EPA proposes. These current data also show 
that Wichita Mountains is projected to meet the EPA approved uniform 
rate of progress for Oklahoma, and the Guadalupe Mountains is projected 
to meet the EPA-proposed uniform rate of progress by 2018, without the 
emission controls that EPA is proposing. Yet EPA ignores these actual 
conditions in developing its reasonable progress goals and in 
concluding that its reasonable progress goals are more reasonable. EPA 
has no authority to require further controls from Texas sources and 
should

[[Page 342]]

withdraw its FIP and approve the Texas SIP.
    Response: These comments are predicated on two false tests: (1) If 
a Class I area meets its uniform rate of progress, or (2) if subsequent 
monitoring shows a Class I area meets its reasonable progress goals, it 
is automatically relieved of any obligation to address the reasonable 
progress and long-term strategy requirements in Sec.  51.308(d)(1) and 
(3).
    We discuss elsewhere in this final action that, while we agree that 
the Regional Haze Rule requires states to consider the uniform rate of 
improvement in visibility when formulating reasonable progress goals, 
we disagree that a state's consideration of the uniform rate of 
progress and establishment of reasonable progress goals that provide 
for a slightly greater rate of improvement in visibility than would be 
needed to attain the uniform rate of progress is all that is needed to 
satisfy the reasonable progress goal requirements in the Regional Haze 
Rule. We also disagree that the Regional Haze Rule requires additional 
analysis only when a state establishes reasonable progress goals that 
provide for a slower rate of improvement than the uniform rate of 
progress. Even when recent data from IMPROVE monitors indicate that 
visibility conditions in the Class I area are better than the 
established reasonable progress goals and/or that the area may be 
projected to meet the uniform rate of progress by 2018, the state must 
still address the requirements under Sec.  51.308(d)(1) and (d)(3)(i) 
in evaluating controls for additional sources and in establishing 
reasonable progress goals for its Class I areas.
    With regard to the assertion that Texas' five-year regional haze 
progress report projects SO2 and NOX emissions 
from point sources to continue to decline through 2018 (with 
corresponding visibility improvement trends at the three Class I 
areas), Texas' five-year regional haze progress report is pending 
evaluation as a SIP revision, and we intend to take action on it in a 
future rulemaking. We note that the portion of the Texas' five-year 
regional haze progress report referred to by the commenters \196\ 
compares actual annual emissions from 2002 through 2011 against a 
linear change between 2002 actual emissions and the 2018 CENRAP modeled 
emissions and concludes that emissions from 2002 to 2011 have trended 
downward better than or as predicted in the CENRAP modeling 
projections. However, we noted in our proposal that the CENRAP 
projected visibility impacts in 2018 from Texas point sources, and EGUs 
in particular, are significant. As noted in our proposed rulemaking, 
based on information provided by the TCEQ in materials other than the 
progress report, we do not expect large additional emission reductions 
of SO2 in Texas between 2013 and 2018 under Federal programs 
and the SIP as submitted.\197\ We have not seen evidence in support of 
something different. Furthermore, emissions from some of the Texas EGUs 
that we are requiring controls for and that impact visibility at the 
three Class I areas the most, are still above the emission level 
projected in the 2018 CENRAP modeling. We are not aware of any upcoming 
controls or changes in operation to suggest that future actual 
emissions at these specific sources will decrease to those predicted 
levels.
---------------------------------------------------------------------------

    \196\ 2014 Texas Five-Year Reasonable Progress Report, p 4-10, 
figure 4-2.
    \197\ TCEQ comment letter to EPA on draft modeling platform 
dated June 24, 2014.
---------------------------------------------------------------------------

    We also remind the commenters that even with the controls we are 
requiring for Texas EGUs under our FIP, additional reductions would be 
needed for visibility conditions to meet or exceed every uniform rate 
of progress goal in 2018 as calculated by us in our proposal. For 
example, current conditions at the Wichita Mountains (based on 2009-
2013) is 21.2 dv. Additional reductions would be needed for the area to 
meet the uniform rate of progress goal of 20.01 dv in 2018.
    Comment: The SO2 emissions from Luminant's units, for 
which EPA proposed controls, have steadily trended downward over the 
first planning period, further underscoring the effectiveness of the 
measures relied on in Texas' SIP and the unreasonableness of EPA's 
proposed FIP. From 2009 to 2014, SO2 emissions from 
Luminant's Big Brown, Martin Lake, Monticello, and Sandow Unit 4 were 
reduced by 27%. The SO2 emissions for the first quarter of 
2015 are sharply lower--approximately 57% lower than the first quarter 
of 2009 and about 44% lower than the first quarter of 2014. The data 
unequivocally show that SO2 emissions at Luminant's units 
are trending down, and thus there is no basis for EPA's proposal.
    Response: The annual and quarterly SO2 emissions data 
for Luminant's facilities for 2009-2015 demonstrate that, although 
there has been an overall downward trend in annual SO2 
emissions during this time period, there has not been a downward trend 
in SO2 emissions during Quarter 3 for the six-year period 
for which full data are available. Except for the years 2011 and 2012, 
when total SO2 emissions for Quarter 3 were either sizably 
higher or lower compared to the other years during the 2009-2014 time 
period, emissions for Quarter 3 remained relatively unchanged during 
this six year period. This is significant because Quarter 3 corresponds 
to the summer months and many of the 20% worst days, which is what the 
reasonable progress goals are based on, typically occur during the 
summer months. Emissions reductions during the fall and/or winter 
months reduce annual emissions, but will not lead to improved 
visibility during the 20% worst days. The majority of the decline in 
total annual SO2 emissions from the Luminant sources is 
driven by seasonal operation of Monticello units 1 and 2.\198\ 
Furthermore, as we discuss in more detail elsewhere, we do not 
anticipate any significant reductions at these sources in the near 
future, and information provided by Texas indicates it agrees.\199\ We 
also note, as discussed above, NOX emissions for many of 
these units were updated in our modeling to better reflect the recent 
actual emissions. Therefore, we disagree that the observed trend in 
SO2 emissions at Luminant's units in recent years 
demonstrates that there is no basis for EPA's proposal.
---------------------------------------------------------------------------

    \198\ See Luminant CAMD emissions.xlsx in the docket for this 
action.
    \199\ See TCEQ comment letter to EPA on draft modeling platform 
dated June 24, 2014 available in the docket for this action.
---------------------------------------------------------------------------

    Comment: To the extent Texas and industry are arguing that the 
current visibility conditions meet the reasonable progress goals EPA is 
proposing, that is largely a result of the fact that EPA has not 
updated the majority of the 2018 projections that CENRAP and Texas 
relied on. Goals based on the controls EPA has proposed and also on 
more updated projections would likely be lower than the reasonable 
progress goals EPA is proposing. The recent improvement is due to a 
variety of factors, which EPA discusses in the proposed rule, 79 FR 
74843, most of which are not enforceable limitations or are beyond the 
state's control and, therefore, may be temporary. The argument made by 
Texas and industry does not show that the proposed controls themselves 
are unnecessary or unreasonable. Further, the argument by Texas and 
industry reflects a misunderstanding of how reasonable progress goals 
are set. Reasonable progress goals are set to reflect controls that are 
reasonable; controls are not required in order to meet pre-set 
reasonable progress goals. Congress

[[Page 343]]

defined reasonable progress as the amount of progress that could be 
made after consideration of four factors. 42 U.S.C. 7491(g)(1). After 
the four-factor analysis defines reasonable progress, each haze SIP 
must include the enforceable measures necessary to make reasonable 
progress. Id. section 7491(b)(2). The reasonable progress goal for 2018 
is calculated as the baseline visibility condition minus the amount of 
reasonable progress (which is established based on consideration of the 
four statutory factors).
    Response: We generally agree with the commenter and agree that 
these comments provide support of our FIP.
    Comment: EPA fails to even consider the four statutory factors with 
respect to non-BART sources in Oklahoma that are impacting visibility 
at the Wichita Mountains and to determine whether all existing and 
reasonable controls on Oklahoma sources, including BART, are sufficient 
to attain a reasonable rate of progress for the Wichita Mountains for 
the first planning period. EPA does not explain why it failed to 
conduct the modeling and perform the statutory analysis that it would 
expect a state to conduct in determining a reasonable progress goal.
    EPA failed to consider the visibility benefit from imposing the 
same levels of control on these sources as it is proposing to impose on 
the targeted Texas sources. EPA is applying a different standard to 
Texas sources than it is to sources in other states. EPA's ``reset'' 
reasonable progress goal is unlawful; and EPA has no basis for 
disapproving Oklahoma's reasonable progress goal, no basis for issuing 
a FIP with a substitute reasonable progress goal for the Wichita 
Mountains, no basis for disapproving Texas' long-term strategy, and no 
basis for imposing additional SO2 limits on Texas sources.
    Response: We disapproved Texas' long-term strategy because it was 
technically flawed and we were under a statutory obligation to evaluate 
Texas sources and propose a FIP for those facilities where we 
determined that reasonable emission controls could be installed for 
improved visibility benefit.
    Oklahoma's lack of adequate information from Texas prevented it 
from properly developing its reasonable progress goals for the Wichita 
Mountains, and we disagree that we are applying a different standard to 
Texas sources than we are sources in other states. We note that we were 
not required to do a four-factor analysis for Oklahoma's non-BART 
sources because, as discussed in our proposal \200\ and OK TSD, we 
reviewed Oklahoma's four-factor analysis for Oklahoma's non-BART 
sources, and agree with Oklahoma that it has demonstrated that it is 
not reasonable to require additional emission reductions for those 
sources for this planning period. We agree with Oklahoma's reasonable 
progress analysis for sources within Oklahoma and its assessment that 
the Wichita Mountains would not meet the uniform rate of progress 
without significant reductions from Texas sources. Because the 
reasonable progress goals Oklahoma established for the Wichita 
Mountains does not include appropriate consideration of reductions at 
Texas sources, we were required by the Regional Haze Rule to disapprove 
Oklahoma's reasonable progress goals. We recalculate new reasonable 
progress goals for 2018 for the Wichita Mountains based on the results 
of our technical analysis that additional controls at Texas sources 
were reasonable to meet the reasonable progress/long-term strategy 
requirement for reasonable progress and accounting for the visibility 
benefit of the required controls anticipated to be in place by 2018.
---------------------------------------------------------------------------

    \200\ 79 FR 74871.
---------------------------------------------------------------------------

R. International Emissions

    Comment: EPA acknowledged it failed to account for international 
sources of emissions, which Texas cannot control. This renders its 
proposal ineffective in improving visibility to meet the uniform rate 
of progress and 2064 goal. EPA's action would require over-control of 
Texas sources to compensate for international emissions. If the TCEQ 
cannot meet the glide path without ``large emission reductions from 
international sources,'' it is unreasonable for EPA to require 
additional controls from Texas without making any effort to seek 
emissions reductions from international sources.
    Response: We agree with the commenters that international emissions 
significantly impact visibility conditions at Big Bend and the 
Guadalupe Mountains. However, as we discussed in the preamble to the 
Regional Haze Rule, ``the States should not consider the presence of 
emissions from foreign sources as a reason not to strive to ensure 
reasonable progress in reducing any visibility impairment caused by 
sources located within their jurisdiction.'' While the goal of the 
regional haze program is to restore natural visibility conditions at 
Class I areas by 2064, the rule requires only that reasonable progress 
be made towards the goal during each planning period, and in cases 
where it is not reasonable to meet the rate of progress needed to 
attain the goal in 2064, that the state demonstrate that it is not 
reasonable and that the selected rate of progress is reasonable for 
that planning period. We recognize that it may not be possible to 
attain the goal by 2064, or at all, because of impacts from new or 
persistent international emissions sources or impacts from sources 
where reasonable controls are not available. However, states are still 
required to demonstrate that they are establishing a reasonable rate of 
progress that includes implementation of reasonable measures within the 
state to address visibility impairment in an effort to make progress 
towards the natural visibility goal during each planning period. 
Nothing in the Regional Haze Rule or our FIP is calculated to hold 
Texas accountable for emissions from Mexico. We agree those 
international emissions should be addressed to achieve natural 
visibility, but our agreement on this point does not in any way relieve 
Texas of the obligation to make reasonable progress, including through 
controls on its own sources, and particularly through the emissions 
addressed with controls through our FIP.
    Comment: EPA is not doing enough to seek emission reductions from 
international sources. Commenters noted that we committed to address 
international emissions in our 1999 Regional Haze Rule when we stated, 
``EPA will work with the governments of Canada and Mexico to seek 
cooperative solutions on transboundary pollution problems (64 FR 35714, 
35736),'' but have thus far done little.
    Response: We acknowledge that Texas requested in its SIP that we 
initiate and pursue Federal efforts to reduce impacts from 
international transport. There are efforts underway to address public 
health problems related to air emissions along the United States-Mexico 
border. Given that emissions contributing to health effects and those 
contributing to visibility impairment are generally the same, the 
border studies and continuing emissions inventory development will aid 
in identifying solutions that we would expect to also address 
visibility impairment. The Border 2020 program aims to, among other 
things, reduce air pollution to help meet the NAAQS and reduce emission 
through the use of energy efficiency and/or alternative/renewable 
energy projects. We expect that recent commitments from Mexico to 
reduce its carbon dioxide and black carbon emissions will have 
ancillary benefits to improve visibility at Class I areas in the 
future.
    Comment: It is not possible for Texas to achieve the uniform rate 
of progress because of the contribution from

[[Page 344]]

Mexico. An analysis shows that if every point source in Texas were shut 
down, it would have only a marginal impact on visibility in the 
Guadalupe Mountains. Further, the exclusion of all of Texas and other 
United States elevated point sources resulted in a modeled haze index 
value of 14.88 dv, meaning that Mexican sources and natural 
contributions are projected to account for 92%, or all but 1.48 
deciviews, of visibility impairment in the Guadalupe Mountains.
    Response: The commenter erroneously overstates the size of the 
visibility impacts from Mexico relative to Texas. As we stated in our 
proposal, efforts to meet the goal of natural visibility by 2064 
``would require further emissions reductions not only within Texas, but 
also large emission reductions from international sources'' (emphasis 
added).\201\ The commenter's analysis fails to account for impacts from 
mobile and area sources within Texas and other states, and fails to 
differentiate Mexican sources from other international sources. The 
analysis also fails to consider that deciviews are a logarithmic 
function of extinction, resulting in the underestimation of the percent 
contribution from Texas and U.S. point sources. Overall impacts from 
all sources in Texas are larger than all sources in Mexico and the 
boundary conditions (which represent external sources) combined. As we 
discuss in our proposal and elsewhere in our response to comments, 
Texas and we agreed that it was reasonable to focus on impacts from 
point sources for this planning period. The visibility impairment from 
Texas point sources is significant, and as our analysis shows, a 
significant portion of this impairment can be addressed by controlling 
a small number of sources. Controls on just four units at Tolk and Big 
Brown are estimated to reduce visibility impairment due to all Texas 
point sources at the Guadalupe Mountains by approximately 13%. All 
required controls combined are estimated to reduce visibility 
impairment at the Guadalupe Mountains from all Texas point sources by 
approximately 22%.
---------------------------------------------------------------------------

    \201\ 79 FR 74843.
---------------------------------------------------------------------------

    Comment: CCP (through its contractor, AECOM) stated that back 
trajectories for 2011-2013 indicate that approximately 77% of the 20% 
worst day trajectories at the Guadalupe Mountains passed through 
Mexico. For Big Bend, this percentage increases to about 96%. Mexican 
point sources, particularly Carbon I and Carbon II, are only about 230 
km away from Big Bend, while the nearest Texas facility with a proposed 
new emission limit is about 500 km away. Emissions from these large 
power plants are noteworthy--Carbon II emitted 162,329 tons of 
SO2 in 2008, according to the draft EPA 2011 modeling 
platform, which is an increase from 1997 (129,341 tons at Carbon II). 
In addition to international point sources, smoke plumes from 
agricultural fires in Central America travel northward into the U.S. 
and contribute to haze. Modeling shows that the sources that cause haze 
in Big Bend and the Guadalupe Mountains are rarely in the area where 
most of the emission sources targeted by EPA are located. The effect of 
controlling emissions at a plant like Big Brown would be dwarfed by the 
massive impact of the international emissions. CCP reasons that since 
the emissions from its facility, Coleto Creek, are even lower than Big 
Brown's emissions, it would have a smaller impact. This component of 
haze must be accounted for in regional haze SIPs in the development of 
reasonable progress goals and/or natural conditions because these 
emissions from agricultural burns, power plants, or wildfires from 
international sources are beyond the jurisdiction of state agencies.
    Response: We have reviewed the back trajectories provided and have 
noted several flaws in the analysis and conclusions. In general, back 
trajectories are tools that may be used for analyzing potential upwind 
contribution areas to a monitored value of concern. In this case we 
generally agree that many back trajectories do pass through upwind 
areas in Mexico for the 20% worst monitored days at Big Bend and the 
Guadalupe Mountains. What the commenter fails to point out or conclude 
is that a very large percentage of the trajectories that the commenter 
attributes to Mexico also cross over or near areas of Texas, thus 
indicating that Texas is also a potential contributor to the high 
monitored values at Big Bend and the Guadalupe Mountains. We do agree 
that impacts from Mexico are significant and must be addressed to 
achieve natural visibility, but our agreement on this point does not in 
any way relieve Texas of the obligation to make reasonable progress, 
including through controls on its own sources, and particularly through 
the emissions addressed with controls through our FIP. Past analyses 
have indicated that impacts from Texas on Big Bend and the Guadalupe 
Mountains are as large as impacts from Mexico and that reducing impacts 
from sources in Texas is also necessary to achieve natural 
visibility.\202\ We disagree that impacts from Coleto Creek would be 
smaller than impacts from Big Brown because it has fewer emissions. The 
comment failed to consider the location of the source and the 
meteorology/transport conditions. Coleto Creek is closer to Big Bend 
and our source apportionment modeling shows that the one unit at Coleto 
Creek has a larger impact on the 20% worst days at Big Bend than the 
impact from the two units at Big Brown.
---------------------------------------------------------------------------

    \202\ See FIP TSD pages A-30-32 and A-65-66 and Conclusions of 
BRAVO study source apportionment techniques (TX166.017 
BravoFactSheet20040915.pdf and BRAVOFinalReportCIRA.pdf).
---------------------------------------------------------------------------

    The comment presents a comparison between the visibility impact 
from one facility to the visibility impact from all sources around the 
world that lie outside of the modeling domain, including long range 
transport from fires, windblown dust, and significant anthropogenic 
emissions. The commenter states that annual average visibility 
impairment from Big Brown is approximately 10% of the annual average 
contribution from those sources captured by the boundary conditions. 
This is a significant fraction of the total visibility impairment that 
can be addressed through the installation of controls on merely two 
emission units. We also note that visibility impairment on the 20% 
worst days at each Class I area from Big Brown is larger; and as can be 
seen by the data submitted by the commenter, on some days, the 
visibility impairment due to Big Brown's emissions approaches or 
exceeds that from all emissions sources captured by the boundary 
conditions. For the Wichita Mountains, controls on just Big Brown 
address almost 12% of the total visibility impairment due to Texas 
point sources and 1.63% of the total visibility impairment from all 
sources. In summary, the visibility impairment from the individual 
sources analyzed is significant, and controls on these sources provide 
for meaningful progress towards the goal of natural visibility 
conditions at one or more Class I areas. This is not inconsistent with 
the understanding that significant impacts from international emissions 
and other sources exist and should also be addressed.
    Lastly, we agree with CCP that the sources it cites, Carbon I and 
Carbon II, are responsible for significant levels of pollution. Carbon 
I is a 1,200 MW power plant and Carbon II is a 1,400 MW coal-fired 
power plant. These two power plants, less than 1.5 miles apart, are 
less than 20 miles from the U.S.-Mexico border. Together, these power 
plants comprise one of the largest

[[Page 345]]

uncontrolled sources of SO2 and NOX in North 
America.\203\ It has been demonstrated for some time that they are 
significant contributors to visibility impairment at Big Bend.\204\ 
However, addressing international emissions can be complex. For 
instance, Texas has recently issued water discharge and mining permits 
to a coal mine in Maverick County, near the Texas border town of Eagle 
Pass, to allow the Mexican company Dos Republicas to begin mining coal 
that will reportedly be sent to these facilities.\205\ Prior to our 
delegation of the National Discharge Elimination System (NPDES) 
permitting authority to Texas, we issued a NPDES permit for the 
operation of this mine, and in the process issued an Environmental 
Impact Statement (EIS).\206\ In our EIS, we stated that ``. . . EPA 
does not have the authority to prohibit export of U.S. resources which 
will cause the country environmental harm . . . EPA believes that the 
U.S. policy should be to take actions which will generate the 
investment capital needed to directly solve the Carbon I/II problem'' 
\207\ Subsequent to that, we attempted to work with the government of 
Mexico specifically on the problem of installing controls on these 
sources through a technical work group composed of EPA and SEMARNAP 
(now SEMARNAT, the Mexican Environment and Natural Resources 
Secretariat) staff. Unfortunately, these discussions did not result in 
any control of Carbon I and II. However, EPA is committed to explore 
opportunities for further discussions with Mexico concerning this 
subject.
---------------------------------------------------------------------------

    \203\ Commission for Environmental Cooperation of North America, 
``North American Power Plant Air Emissions,'' http://www.cec.org/storage/56/4876_powerplant_airemission_en.pdf. TCEQ may keep this in 
consideration in future studies on the impacts of sources from 
Mexico on Class I areas or otherwise.
    \204\ Big Bend Regional Aerosol and Visibility Observational 
Study (BRAVO), Final Report, September 2004.
    \205\ http://www.epbusinessjournal.com/2015/11/dos-republicas-coal-partnership-coal-mine-expanded-water-discharge-permit-application-to-be-heard-november-16th/.
    \206\ Authorization to Discharge Under the National Pollutant 
Discharge Elimination System. Permit No. TX0109011.
    \207\ Final Environmental Impact Statement on Dos Republicas 
Resource Company, Inc.'s Proposed Eagle Pass Mine in Maverick 
County, Texas, December 30, 1994. Page C-51.
---------------------------------------------------------------------------

S. Grid Reliability

    Comment: The TCEQ recommended that we withdraw the proposed FIP; 
however, if we do finalize the FIP, it believed we should include an 
electric reliability safety valve provision in the final rule. The TCEQ 
stated that we have not evaluated any potential impacts of our proposed 
FIP to reliability and prices of electricity in Texas. It included a 
2014 ERCOT study of the impacts that environmental regulations have in 
the ERCOT Region. While the ERCOT report included a number of other 
environmental regulations, such as the MATS rule, Clean Power Plan, and 
CSAPR, ERCOT also included our proposed regional haze FIP for Texas in 
its analysis. The TCEQ incorporated the ERCOT report into its comments 
and encouraged us to consider its findings.
    Response: First, we note that controls achieving the level of 
control that we are requiring are highly cost-effective, are in wide 
use in the industry, and thus should not require a source to shut down 
to comply. In response to the TCEQ's comments, however, we contracted 
with Synapse Energy Economics, Inc., a nationally recognized firm with 
particular expertise in the subject area. (Synapse).\208\ Synapse 
assessed the information in the ERCOT report and we reproduce its 
findings below:
---------------------------------------------------------------------------

    \208\ Synapse's report, 
``ERCOT_Report_Review_Memo_20150908.pdf'' is in our docket to this 
rulemaking action.

    1. ERCOT's perspective of market operations is 
short[hyphen]sighted. ERCOT raises concerns that reliability could 
be impacted if numerous coal units choose to retire simultaneously 
with little notice to either ERCOT or other market participants. 
Unlike other competitive market regions, ERCOT's rules do not 
require meaningful notice. ERCOT's charge as a reliability 
coordinator may obligate it to implement rules requiring reasonable 
notice for economic retirements.
    2. ERCOT's assumptions about new gas turbine capacity are not 
realistic. While the FIP, along with other environmental regulations 
ERCOT included in its study, will strain the economic viability of 
coal plants and likely lead to less coal capacity, ERCOT has not 
considered new resources that will be available to help address 
potential reliability challenges. Specifically, ERCOT does not 
include approximately 4,500 MW of additional gas[hyphen]fired 
capacity coming online in Texas in the upcoming years. This 
represents 7.5 percent of current gas capacity, and would double the 
modeled baseline gas capacity additions through 2029.
    3. The set of regulatory scenarios modeled is both incomplete 
and (now) outdated. Despite an overall thorough analysis ERCOT 
excluded a critical scenario that would have modeled the impact of 
the Regional Haze Program FIP by itself. This limits inferences we 
can make about impacts. Additionally, since ERCOT finalized its 
study, EPA finalized the Clean Power Plan. The final rule includes 
substantive changes that are likely to affect all of the 
CO2 limit and price-inclusive scenario modeling results.
    4. Electric Generating Unit owners' compliance ``burdens'' with 
the regional haze FIP may be over[hyphen]stated. Of the 15 
coal[hyphen]fired units subject to regional haze compliance 
requirements, eight require upgrades to their existing scrubbers 
rather than new scrubbers. ERCOT assumed that all of the scrubbers 
would be priced at the cost of a new retrofit, thereby substantially 
increasing the cost of the regulation.

    We reviewed and accept our contractor's finding and adopt its 
conclusion that ERCOT's report contained significant flaws. In sum, 
ERCOT's report cannot support a determination that there is likely to 
be any significant, adverse effect on the supply, distribution, or use 
of energy. During our comment period, we received no non-speculative 
information to validate claims that sources would retire rather than 
install demonstrably cost-effective controls. Commenters who have 
alleged grid reliability concerns in response to our proposed controls 
have not provided adequate documentation for their assertions.

T. Determination of Nationwide Scope and Effect

    Several commenters disagreed with our proposed determination of 
``nationwide scope and effect,'' which would require all petitions for 
judicial review to be filed in the U.S. Court of Appeals for the 
District of Columbia Circuit Court. These commenters argued that our 
proposed action did not have nationwide scope and effect because it 
applied only to two states. They further argued that the control 
requirements in the FIP applied only to sources in Texas. The 
commenters acknowledged that the proposed action involved our 
interpretation of our regulations, but asserted that the same is true 
for many SIP actions. The commenters went on to cite several regional 
haze SIP actions where we did not make a finding of nationwide scope 
and effect as evidence that our proposal to do so in this instance was 
unlawful. Ultimately, these commenters concluded that our proposed 
action was ``locally or regionally applicable'' and that any future 
petitions for review must be filed in the appropriate regional circuit. 
Some commenters suggested that judicial review would only be 
appropriate in the Fifth Circuit.
    We disagree with these comments. The commenters are conflating two 
distinct portions of the CAA's judicial review provision. Under CAA 
section 307(b)(1), ``[a] petition for review of . . . nationally 
applicable regulations promulgated, or final agency action taken, by 
the Administrator . . . may be filed only in the United States Court of 
Appeals for the District of Columbia.'' Contrary to the commenter's 
assertions, we did not assert at proposal, nor do we

[[Page 346]]

assert now, that our FIP for Texas and Oklahoma is a ``nationally 
applicable'' regulation. CAA section 307(b)(1) next provides that ``[a] 
petition for review of the Administrator's action in approving or 
promulgating any implementation plan under section 7410 . . . or any 
other final action of the Administrator . . . which is locally or 
regionally applicable may be filed only in the United States Court of 
Appeals for the appropriate circuit.'' The commenters cite this 
sentence, but ignore the following sentence, which states 
``[n]otwithstanding the preceding sentence a petition for review of any 
action referred to in such sentence may be filed only in the United 
States Court of Appeals for the District of Columbia if such action is 
based on a determination of nationwide scope or effect and if in taking 
such action the Administrator finds and publishes that such action is 
based on such determination.''
    In other words, a final agency action that is locally or regionally 
applicable, such as a FIP, is appealable only in the D.C. Circuit Court 
if two conditions are met: (1) The action is based on a determination 
of nationwide scope or effect, and (2) we find and publish our 
determination. Both conditions are met here. First, we proposed to find 
and have confirmed our finding in this final rule that our action on 
the Texas and Oklahoma regional haze SIPs, which includes the 
promulgation of a partial FIP for each state, is based on a 
determination of nationwide scope and effect. Second, we have published 
that finding in the Federal Register.
    While the CAA does not provide any guidance regarding the phrase 
``nationwide scope and effect,'' the legislative history indicates that 
a determination of nationwide scope and effect is appropriate if a 
local or regional action encompasses two or more judicial circuits. The 
commenters made no effort to explain why this legislative history 
should not be taken into account. Instead, the commenters cited to 
other EPA actions on regional haze SIPs where we did not make a 
determination of nationwide scope and effect. However, the commenters 
failed to mention that all of these actions involved a single state and 
thus did not implicate multiple judicial circuits. We have routinely 
made determinations of nationwide scope and effect when more than one 
circuit is involved. Last year, for instance, we made a determination 
of nationwide scope and effect in a SIP approval action that involved 
the States of Florida and North Carolina, which reside in separate 
judicial circuits.\209\ We have made many other such determinations 
over the years.
---------------------------------------------------------------------------

    \209\ See 79 FR 29362.
---------------------------------------------------------------------------

    We also determined that this action has nationwide scope and effect 
because at the core of this rulemaking is our interpretation of the 
requirements of sections 110(a)(2)(D)(i)(II) and 169A(b)(2) of the CAA 
and multiple complex provisions of the Regional Haze Rule. Many 
commenters disagreed with our interpretation of these provisions, with 
some providing alternative interpretations that would substantially 
eviscerate the Regional Haze Rule. Congress intended for such issues of 
national importance to be decided by the D.C. Circuit.

III. Final Action

    For the reasons discussed more fully in section II, above and 
detailed in our proposal and its accompanying TSDs, in this action, we 
are partially approving and partially disapproving a revision to the 
Texas SIP received from the State of Texas on March 31, 2009, that 
intended to address regional haze for the first planning period from 
2008 through 2018. We also are disapproving the interstate visibility 
transport portions of the Texas SIP that address CAA provisions for 
prohibiting air pollutant emissions from interfering with measures 
required to protect visibility in any other state. We also are 
partially disapproving a revision to the Oklahoma SIP submitted in 
February 19, 2010, that addresses regional haze for the first planning 
period. We are finalizing a FIP to remedy certain of the deficiencies 
and not acting on others. Below is a list of the specific actions we 
are finalizing in this rulemaking.

A. Texas Regional Haze

    We are approving the portions of the Texas regional haze SIP 
submitted on March 31, 2009, except for the following Regional Haze 
Rule requirements contained in 40 CFR part 51:
     Section 51.308(d)(1)(i)(A), regarding Texas' reasonable 
progress four-factor analysis for the Guadalupe Mountains and Big Bend.
     Section 51.308(d)(1)(i)(B), regarding Texas' calculation 
of the emission reductions needed to achieve the uniform rates of 
progress for the Guadalupe Mountains and Big Bend.
     Section 51.308(d)(1)(ii), regarding Texas' reasonable 
progress goals for the Guadalupe Mountains and Big Bend.
     Section 51.308(d)(2)(iii), regarding Texas' calculation of 
natural visibility conditions.
     Section 51.308(d)(2)(iv)(A), regarding Texas' calculation 
of the number of deciviews by which baseline conditions exceed natural 
visibility conditions.
     Section 51.308(d)(3)(i), regarding Texas' long-term 
strategy consultations with Oklahoma.
     Section 51.308(d)(3)(ii), regarding Texas securing its 
share of reductions necessary to achieve the reasonable progress goals 
at Big Bend, the Guadalupe Mountains, and the Wichita Mountains.
     Section 51.308(d)(3)(iii), regarding Texas' technical 
basis for its long-term strategy for Big Bend, the Guadalupe Mountains 
the Wichita Mountains.
     Section 51.308(d)(3)(v)(C), regarding Texas' emission 
limitations and schedules for compliance to achieve the reasonable 
progress goals for Big Bend and the Guadalupe Mountains and Wichita 
Mountains.
    We are also approving the Texas' BART Rules, 30 TAC 116.1500-
116.1540, except for the 30 TAC 116.1510(d) which relies on CAIR and is 
disapproved.
    We are not taking action on 40 CFR 51.308(e) concerning Texas EGU 
BART.

B. Oklahoma Regional Haze

    We are disapproving the portion of the Oklahoma regional haze SIP 
that addresses the requirements of 40 CFR 51.308(d)(1) with respect to 
reasonable progress goals, with the exception of Sec.  
51.308(d)(1)(vi), which we are approving.

C. Interstate Visibility Transport

    We are disapproving portions of Texas SIP submittals that address 
CAA provisions for prohibiting air pollutant emissions from interfering 
with measures required to protect visibility in any other state for the 
1997 PM2.5, 2006 PM2.5, 1997 ozone, 2008 ozone, 
2010 NO2, and 2010 SO2 NAAQS. Our final FIP does 
not cure these defects as that portion of the FIP would have partially 
relied on CSAPR. We will address the visibility transport requirements 
for Texas in a future rulemaking, once the issues surrounding the CSAPR 
partial remand are resolved.

D. Federal Implementation Plan

    Our final FIP requires the following SO2 emission limits 
for specific emission units in Texas:

[[Page 347]]



       Table 7--Final 30-Boiler-Operating-Day SO2 Emission Limits
------------------------------------------------------------------------
                                                           SO2 Emission
                          Unit                             limit  (lbs/
                                                              MMBtu)
------------------------------------------------------------------------
Sandow 4................................................            0.20
Martin Lake 1...........................................            0.12
Martin Lake 2...........................................            0.12
Martin Lake 3...........................................            0.11
Monticello 3............................................            0.06
Limestone 2.............................................            0.08
Limestone 1.............................................            0.08
Big Brown 1.............................................            0.04
Big Brown 2.............................................            0.04
Monticello 1............................................            0.04
Monticello 2............................................            0.04
Coleto Creek 1..........................................            0.04
Tolk 172B...............................................            0.06
Tolk 171B...............................................            0.06
San Miguel..............................................            0.60
------------------------------------------------------------------------

    Compliance with these emission limits is based on a 30 BOD period. 
We are finalizing requirements providing that compliance with these 
limits be achieved within:
     Five years of the effective date of our final rule for Big 
Brown Units 1 and 2, Monticello Units 1 and 2, Coleto Creek Unit 1, and 
Tolk Units 171B and 172B.
     Three years of the effective date of our final rule for 
Sandow 4; Martin Lake Units 1, 2, and 3; Monticello Unit 3; and 
Limestone Units 1 and 2.
     One year of the effective date of our final rule for San 
Miguel. San Miguel may elect an alternative compliance method by doing 
the following:
     Install a CEMS at the inlet of the scrubber system. The 30 
BOD SO2 average from the existing outlet CEMS must read at 
or below 6.0% (94% control) of a 30 BOD SO2 average from the 
inlet CEMS. San Miguel must inform us in writing of its decision to 
select this option for compliance by no later than their compliance 
date.

Based on our technical analysis, we have calculated the following in 
Tables 8 and 9 for Texas and Oklahoma:

   Table 8--Natural Visibility Conditions, Number of Deciviews by Which Baseline Conditions Exceed Natural Visibility Conditions, and Uniform Rate of
                                                                   Progress for Texas
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             Natural visibility conditions              Number of deciviews by which baseline
                                   ------------------------------------------------     conditions  exceed natural visibility
           Class I area                                                                               conditions                      Uniform rates of
                                           20% Worst               20% Best        -----------------------------------------------    progress at 2018
                                                                                           20% Worst               20% Best
--------------------------------------------------------------------------------------------------------------------------------------------------------
Guadalupe Mountains...............  6.65 dv...............  0.99 dv...............  10.54 dv..............  4.96 dv..............  14.73 dv.
Big Bend..........................  7.16 dv...............  1.62 dv...............  10.14 dv..............  4.16 dv..............  14.93 dv.
--------------------------------------------------------------------------------------------------------------------------------------------------------


        Table 9--Reasonable Progress Goals for Texas and Oklahoma
------------------------------------------------------------------------
                                        Reasonable progress goals
          Class I area          ----------------------------------------
                                      20% Worst            20% Best
------------------------------------------------------------------------
Guadalupe Mountains............  16.26 dv...........  5.70 dv.
Big Bend.......................  16.57 dv...........  5.59 dv.
Wichita Mountains..............  21.33 dv...........  9.22 dv.
------------------------------------------------------------------------

IV. Incorporation by Reference

    In this rule, we are finalizing regulatory text that includes 
incorporation by reference. In accordance with the requirements of 1 
CFR 51.5, we are finalizing the incorporation by reference of the 
revisions to the Texas regulations as described in the Final Action 
section above and the amendments to 40 CFR part 52 set forth below. We 
have made, and will continue to make, these documents generally 
available electronically through http://www.regulations.gov and/or in 
hard copy at the EPA Region 6 office.

V. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive 
Order 13563: Improving Regulation and Regulatory Review

    This action is exempt from review by the Office of Management and 
Budget (OMB) because it is not a rule of general applicability. This 
action finalizes a source-specific FIP for that applies to eight coal-
fired power plants in Texas (Big Brown; Monticello; Coleto Creek; Tolk; 
Sandow; Martin Lake; Limestone; and San Miguel).

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under 
the provisions of the PRA, 44 U.S.C. 3501 et seq. Under the PRA, a 
``collection of information'' is defined as a requirement for ``answers 
to . . . identical reporting or recordkeeping requirements imposed on 
ten or more persons . . . '' 44 U.S.C. 3502(3)(A). Because the FIP 
applies to only eight facilities, the Paperwork Reduction Act does not 
apply. See 5 CFR 1320.3(c).

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic 
impact on a substantial number of small entities under the RFA. This 
action will not impose any requirements on small entities. This FIP 
will apply to eight facilities, none of which are small entities. The 
final partial approval of the SIP merely approves state law as meeting 
Federal requirements and does not impose additional requirements.

D. Unfunded Mandates Reform Act (UMRA)

    Title II of the UMRA, 2 U.S.C. 1531-1538, establishes requirements 
for Federal agencies to assess the effects of their regulatory actions 
on state, local,

[[Page 348]]

and Tribal governments and the private sector. Under section 202 of the 
UMRA, EPA generally must prepare a written statement, including a cost-
benefit analysis, for proposed and final rules with ``Federal 
mandates'' that may result in expenditures to state, local, and Tribal 
governments, in the aggregate, or to the private sector, of $100 
million or more (adjusted for inflation) in any one year. Before 
promulgating an EPA rule for which a written statement is needed, 
section 205 of the UMRA generally requires EPA to identify and consider 
a reasonable number of regulatory alternatives and adopt the least 
costly, most cost-effective, or least burdensome alternative that 
achieves the objectives of the rule. The provisions of section 205 of 
UMRA do not apply when they are inconsistent with applicable law. 
Moreover, section 205 of the UMRA allows EPA to adopt an alternative 
other than the least costly, most cost-effective, or least burdensome 
alternative if the Administrator publishes with the final rule an 
explanation why that alternative was not adopted. Before EPA 
establishes any regulatory requirements that may significantly or 
uniquely affect small governments, including Tribal governments, it 
must have developed under section 203 of the UMRA a small government 
agency plan. The plan must provide for notifying potentially affected 
small governments, enabling officials of affected small governments to 
have meaningful and timely input in the development of EPA regulatory 
proposals with significant Federal intergovernmental mandates, and 
informing, educating, and advising small governments on compliance with 
the regulatory requirements.
    EPA has determined that Title II of the UMRA does not apply to this 
rule. In 2 U.S.C. 1502(1) all terms in Title II of UMRA have the 
meanings set forth in 2 U.S.C. 658, which further provides that the 
terms ``regulation'' and ``rule'' have the meanings set forth in 5 
U.S.C. 601(2). Under 5 U.S.C. 601(2), ``the term `rule' does not 
include a rule of particular applicability relating to . . . 
facilities.'' Because this rule is a rule of particular applicability 
relating to eight named facilities, EPA has determined that it is not a 
``rule'' for the purposes of Title II of the UMRA.

E. Executive Order 13132: Federalism

    This action does not have Federalism implications. It will not have 
substantial direct effects on the states, on the relationship between 
the national government and the states, or on the distribution of power 
and responsibilities among the various levels of government. The final 
rule does not impose significant economic costs on state or local 
governments. Thus, Executive Order 13132 does not apply to the final 
rule.

F. Executive Order 13175: Coordination With Indian Tribal Governments

    This action does not have tribal implications as specified in 
Executive Order 13175. This action applies to eight facilities in Texas 
and to Federal Class I areas in Oklahoma and Texas. This action does 
not apply on any Indian reservation land, any other area where EPA or 
an Indian tribe has demonstrated that a tribe has jurisdiction, or non-
reservation areas of Indian country. Thus, Executive Order 13175 does 
not apply to this action.

G. Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks

    Executive Order 13045: Protection of Children From Environmental 
Health Risks and Safety Risks applies to any rule that: (1) Is 
determined to be economically significant as defined under Executive 
Order 12866; and (2) concerns an environmental health or safety risk 
that we have reason to believe may have a disproportionate effect on 
children. This action is not subject to Executive Order 13045 because 
the EPA does not believe the environmental health or safety risks 
addressed by this action present a disproportionate risk to children. 
Moreover, ``regulation'' or ``rule,'' is defined in Executive Order 
12866 as ``an agency statement of general applicability and future 
effect.'' E.O. 12866 does not define ``statement of general 
applicability,'' but this term commonly refers to statements that apply 
to groups or classes, as opposed to statements, which apply only to 
named entities. The FIP therefore is not a rule of general 
applicability because its requirements apply and are tailored to only 
eight individually identified facilities. Thus, it is not a ``rule'' or 
``regulation'' within the meaning of E.O. 12866. However, as this 
action will limit emissions of SO2, it will have a 
beneficial effect on children's health by reducing air pollution.

H. Executive Order 13211: Actions That Significantly Affect Energy 
Supply, Distribution or Use

    This action is not subject to Executive Order 13211 because it is 
not a significant regulatory action under Executive Order 12866.

I. National Technology Transfer and Advancement Act

    This action involves technical standards. Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (``NTTAA''), 
Public Law 104-113, 12(d) (15 U.S.C. 272 note) directs EPA to use 
voluntary consensus standards in its regulatory activities unless to do 
so would be inconsistent with applicable law or otherwise impractical. 
Voluntary consensus standards are technical standards (e.g., materials 
specifications, test methods, sampling procedures, and business 
practices) that are developed or adopted by voluntary consensus 
standards bodies. NTTAA directs EPA to provide Congress, through OMB, 
explanations when the Agency decides not to use available and 
applicable voluntary consensus standards. This rule would require the 
eight affected facilities to meet the applicable monitoring 
requirements of 40 CFR part 75. Part 75 already incorporates a number 
of voluntary consensus standards. Consistent with the Agency's 
Performance Based Measurement System (PBMS), part 75 sets forth 
performance criteria that allow the use of alternative methods to the 
ones set forth in part 75. The PBMS approach is intended to be more 
flexible and cost-effective for the regulated community; it is also 
intended to encourage innovation in analytical technology and improved 
data quality. At this time, EPA is not recommending any revisions to 
part 75; however, EPA periodically revises the test procedures set 
forth in part 75. When EPA revises the test procedures set forth in 
part 75 in the future, EPA will address the use of any new voluntary 
consensus standards that are equivalent. Currently, even if a test 
procedure is not set forth in part 75, EPA is not precluding the use of 
any method, whether it constitutes a voluntary consensus standard or 
not, as long as it meets the performance criteria specified; however, 
any alternative methods must be approved through the petition process 
under 40 CFR 75.66 before they are used.

J. Executive Order 12898: Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations

    The EPA believes the human health or environmental risk addressed 
by this action will not have potential disproportionately high and 
adverse human health or environmental effects on minority, low-income, 
or indigenous populations because it increases the level of 
environmental protection for all

[[Page 349]]

affected populations without having any disproportionately high and 
adverse human health or environmental effects on any population, 
including any minority or low-income population. This FIP limits 
emissions of SO2 from eight facilities in Texas.

K. Congressional Review Act

    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). This rule will be effective on February 4, 2016.

VI. Judicial Review

    The scope and effect of this rulemaking extend to Texas and 
Oklahoma, which are located in two judicial circuits. In addition, 
EPA's clarified interpretation of its regulations as set forth in this 
final action, including the accompanying RTC and TSD documents, is 
applicable to regional haze actions in all states, not just the 
specific actions we are taking here with regard to the regional haze 
obligations for Texas and Oklahoma. Accordingly, the Administrator 
determines that this is a rulemaking of nationwide scope or effect and 
any petitions for review must be filed in the U.S. Court of Appeals for 
the District of Columbia Circuit in accordance with CAA section 
307(b)(1). Petitions for judicial review of this action must be filed 
in the U.S. Court of Appeals for the District of Columbia Circuit by 
March 7, 2016.
    In addition, pursuant to CAA section 307(d)(1)(B), this action is 
subject to the requirements of CAA section 307(d) because it 
promulgates a FIP under CAA section 110(c). 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, extend 
the time within which a petition for judicial review may be filed, or 
postpone the effectiveness of the rule. Per CAA section 307(b)(2), this 
action may not be challenged later in proceedings to enforce its 
requirements.

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by 
reference, Intergovernmental relations, Nitrogen dioxide, Ozone, 
Particulate matter, Reporting and recordkeeping requirements, Sulfur 
dioxides, Visibility, Interstate transport of pollution, Regional haze, 
Best available control technology.

    Dated: December 9, 2015.
Gina McCarthy,
Administrator.
    Title 40, chapter I, of the Code of Federal Regulations is amended 
as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart LL--Oklahoma

0
2. Section 52.1920(e) is amended by revising the entry for ``Regional 
haze SIP'' in the table titled ``EPA-Approved Nonregulatory Provisions 
and Quasi-Regulatory Measures in the Oklahoma SIP'' to read as follows:


Sec.  52.1920  Identification of plan.

* * * * *
    (e) * * *

             EPA-Approved Nonregulatory Provisions and Quasi-Regulatory Measures in the Oklahoma SIP
----------------------------------------------------------------------------------------------------------------
                                        Applicable
      Name of SIP provision        geographic or  non-       State       EPA approval date       Explanation
                                     attainment  area   submittal date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Regional haze SIP:...............  Statewide..........       2/17/2010  3/7/2014, 79 FR      Core requirements
(a) Determination of baseline and                                        12953.               of 40 CFR 51.308.
 natural visibility conditions.                                                               Initial approval
(b) Coordinating regional haze                                                                12/28/2011, 76 FR
 and reasonably attributable                                                                  81728. Approval
 visibility impairment.                                                                       for Sec.
(c) Monitoring strategy and other                                                             51.308(d)(1)(vi) 1/
 implementation requirements.                                                                 5/2016 [Insert
(d) Coordination with States and                                                              Federal Register
 Federal Land Managers.                                                                       citation].
(e) BART determinations except
 for the following SO2 BART
 determinations: Units 4 and 5 of
 the Oklahoma Gas and Electric
 (OG&E) Muskogee plant; and Units
 1 and 2 of the OG&E Sooner plant.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *

0
3. Section 52.1928 is amended by revising paragraphs (a)(3) and (4) and 
adding paragraph (a)(5) to read as follows:


Sec.  52.1928  Visibility protection.

    (a) * * *
    (3) ``Greater RP Alternative Determination'' (Section VI.E);
    (4) Separate executed agreements between ODEQ and OG&E, and ODEQ 
and AEP/PSO entitled ``OG&E RH Agreement, Case No. 10-024, and ``PSO RH 
Agreement, Case No. 10-025,'' housed within Appendix 6-5 of the RH SIP; 
and

[[Page 350]]

    (5) The reasonable progress goals for the first planning period and 
the reasonable progress consultation with Texas for the Wichita 
Mountains Class I area.
* * * * *

Subpart SS--Texas

0
4. Section 52.2270 is amended by:
0
a. In paragraph (c), adding center heading ``Subchapter M: Best 
Available Retrofit Technology (BART)'' and the sections 116.1500, 
116.1510, 116.1520, 116.1530 and 116.1540 under ``Chapter 116 (Reg 6)--
Control of Air Pollution by Permits for New Construction or 
Modification''; and
0
b. In paragraph (e), adding an entry for ``Texas Regional Haze SIP'' at 
the end of the table titled ``EPA Approved Nonregulatory Provisions and 
Quasi-Regulatory Measures in the Texas SIP''.
    The additions read as follows:


Sec.  52.2270  Identification of plan.

* * * * *
    (c) * * *

                                    EPA Approved Regulations in the Texas SIP
----------------------------------------------------------------------------------------------------------------
                                                          State
                                                        approval/
         State citation              Title/subject      submittal    EPA approval date         Explanation
                                                           date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
          Chapter 116 (Reg 6)--Control of Air Pollution by Permits for New Construction or Modification
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                             Subchapter M: Best Available Retrofit Technology (BART)
----------------------------------------------------------------------------------------------------------------
Section 116.1500................  Definitions........    2/25/2009  1/5/2016 [Insert     .......................
                                                                     Federal Register
                                                                     citation].
Section 116.1510................  Applicability and      2/25/2009  1/5/2016 [Insert     116.1510(d) is NOT part
                                   Exemption                         Federal Register     of the approved SIP.
                                   Requirements.                     citation].
Section 116.1520................  Best Available         2/25/2009  1/5/2016 [Insert     .......................
                                   Retrofit                          Federal Register
                                   Technology (BART)                 citation].
                                   Analysis.
Section 116.1530................  Best Available         2/25/2009  1/5/2016 [Insert     .......................
                                   Retrofit                          Federal Register
                                   Technology (BART)                 citation].
                                   Control
                                   Implementation.
Section 116.1540................  Exemption from Best    2/25/2009  1/5/2016 [Insert     .......................
                                   Available Retrofit                Federal Register
                                   Technology (BART)                 citation].
                                   Control
                                   Implementation.
 
                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

* * * * *
    (e) * * *

[[Page 351]]



              EPA Approved Nonregulatory Provisions and Quasi-Regulatory Measures in the Texas SIP
----------------------------------------------------------------------------------------------------------------
                                                           State
                                       Applicable        submittal
      Name of SIP provision        geographic or non-      date/      EPA approval date          Comments
                                    attainment area      effective
                                                           date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Texas Regional Haze SIP.........  Statewide..........    3/19/2009   1/5/2016 [Insert    The following sections
                                                                      Federal Register    are not approved as
                                                                      citation].          part of the SIP: The
                                                                                          reasonable progress
                                                                                          four-factor analysis,
                                                                                          reasonable progress
                                                                                          goals and the
                                                                                          calculation of the
                                                                                          emission reductions
                                                                                          needed to achieve the
                                                                                          uniform rates of
                                                                                          progress for the
                                                                                          Guadalupe Mountains
                                                                                          and Big Bend;
                                                                                          calculation of natural
                                                                                          visibility conditions;
                                                                                          calculation of the
                                                                                          number of deciviews by
                                                                                          which baseline
                                                                                          conditions exceed
                                                                                          natural visibility
                                                                                          conditions; long-term
                                                                                          strategy consultations
                                                                                          with Oklahoma; Texas
                                                                                          securing its share of
                                                                                          reductions necessary
                                                                                          to achieve the
                                                                                          reasonable progress
                                                                                          goals at Big Bend, the
                                                                                          Guadalupe Mountains,
                                                                                          and the Wichita
                                                                                          Mountains; technical
                                                                                          basis for its long-
                                                                                          term strategy and
                                                                                          emission limitations
                                                                                          and schedules for
                                                                                          compliance to achieve
                                                                                          the RPGs for Big Bend,
                                                                                          the Guadalupe
                                                                                          Mountains and Wichita
                                                                                          Mountains.
----------------------------------------------------------------------------------------------------------------


0
6. Section 52.2302 is added to read as follows:


Sec.  52.2302  Federal implementation plan for regional haze.

    (a) Requirements for Martin Lake Units 1, 2, and 3; Monticello 
Units 1, 2, and 3, Limestone Units 1 and 2; Sandow Unit 4; Big Brown 
Units 1 and 2; Coleto Creek Unit 1; Tolk Units 1 and 2; and San Miguel 
affecting visibility.
    (1) Applicability. The provisions of this section shall apply to 
each owner or operator, or successive owners or operators, of the coal 
burning equipment designated as: Martin Lake Units 1, 2, and 3; 
Monticello Units 1, 2, and 3, Limestone Units 1 and 2; Sandow Unit 4; 
Big Brown Units 1 and 2; Coleto Creek Unit 1; Tolk Units 1 and 2; and 
San Miguel.
    (2) Compliance dates. Compliance with the requirements of this 
section is required by February 4, 2019 for Martin Lake Units 1, 2, and 
3; Monticello Unit 3, Limestone Units 1 and 2; and Sandow Unit 4. 
Compliance with the requirements of this section is required by 
February 4, 2021 for Big Brown Units 1 and 2; Monticello Units 1 and 2; 
Coleto Creek Unit 1; and Tolk Units 1 and 2. Compliance with the 
requirements of this section is required by February 4, 2017 for San 
Miguel. These compliance dates apply unless otherwise indicated by 
compliance dates contained in specific provisions.
    (3) Definitions. All terms used in this part but not defined herein 
shall have the meaning given them in the Clean Air Act (CAA) and in 40 
CFR parts 51 and 60. For the purposes of this section:
    24-hour period means the period of time between 12:01 a.m. and 12 
midnight.
    Air pollution control equipment includes selective catalytic 
control units, baghouses, particulate or gaseous scrubbers, and any 
other apparatus utilized to control emissions of regulated air 
contaminants which would be emitted to the atmosphere.
    Boiler-operating-day means any 24-hour period between 12:00 
midnight and the following midnight during which any fuel is combusted 
at any time at the steam generating unit.
    Daily average means the arithmetic average of the hourly values 
measured in a 24-hour period.
    Heat input means heat derived from combustion of fuel in a unit and 
does not include the heat input from preheated combustion air, 
recirculated flue gases, or exhaust gases from other sources. Heat 
input shall be calculated in accordance with 40 CFR part 75.
    Owner or Operator means any person who owns, leases, operates, 
controls, or supervises any of the coal burning equipment designated in 
paragraph (a) of this section.
    Regional Administrator means the Regional Administrator of EPA 
Region 6 or his/her authorized representative.
    Unit means one of the coal fired boilers covered under paragraph 
(a) of this section.
    (4) Emissions limitations--SO2 emission limit. The 
individual sulfur dioxide emission limit for a unit shall be as listed 
in the table in this paragraph (a)(4) in pounds per million British 
thermal units (lb/MMBtu) as averaged over a rolling 30-boiler-
operating-day period.

------------------------------------------------------------------------
                                                           SO2 Emission
                          Unit                             limit  (lbs/
                                                              MMBtu)
------------------------------------------------------------------------
Sandow 4................................................            0.20
Martin Lake 1...........................................            0.12
Martin Lake 2...........................................            0.12
Martin Lake 3...........................................            0.11
Monticello 3............................................            0.06
Limestone 2.............................................            0.08
Limestone 1.............................................            0.08
Big Brown 1.............................................            0.04
Big Brown 2.............................................            0.04
Monticello 1............................................            0.04
Monticello 2............................................            0.04
Coleto Creek 1..........................................            0.04
Tolk 172B...............................................            0.06
Tolk 171B...............................................            0.06
San Miguel..............................................            0.60
------------------------------------------------------------------------

    (i) For each unit, SO2 emissions for each calendar day 
shall be determined by summing the hourly emissions measured in pounds 
of SO2. For each unit, heat input for each boiler-operating-
day shall be determined by adding together all hourly heat inputs, in 
millions of BTU. Each boiler-operating-day of the thirty-day rolling 
average for a unit shall be determined by adding together the pounds of 
SO2 from that day and the preceding 29-boiler-operating-days 
and dividing the total pounds of SO2 by the sum of the heat 
input during the same 30-boiler-operating-day period. The result shall 
be the 30-boiler-operating-day rolling

[[Page 352]]

average in terms of lb/MMBtu emissions of SO2. If a valid 
SO2 pounds per hour or heat input is not available for any 
hour for a unit, that heat input and SO2 pounds per hour 
shall not be used in the calculation of the 30-boiler-operating-day 
rolling average for SO2.
    (ii) In lieu of paragraph (a)(4)(i) of this section, and if San 
Miguel meets paragraph (a)(5)(i) of this section, it may install a CEMS 
at the inlet of the scrubber system. The 30 BOD SO2 average 
from the existing outlet CEMS must read at or below 6.0% (94% control) 
of a 30 BOD SO2 average from the inlet CEMS.
    (5) Testing and monitoring. (i) No later than the compliance date 
as set out in paragraph (a)(2) of this section, the owner or operator 
shall install, calibrate, maintain and operate Continuous Emissions 
Monitoring Systems (CEMS) for SO2 on the units listed in 
paragraph (a)(1) of this section in accordance with 40 CFR 60.8 and 
60.13(e), (f), and (h), and appendix B of part 60 of this chapter. No 
later than the compliance date as set out in paragraph (a)(2), San 
Miguel must submit a letter to the Regional Administrator that informs 
the EPA which compliance option it elects, as specified in paragraph 
(a)(4) of this section. San Miguel must then adhere to the compliance 
method set forth in that letter to the Regional Administrator. All 
owners or operators shall comply with the quality assurance procedures 
for CEMS found in 40 CFR part 75. Compliance with the emission limits 
for SO2 shall be determined by using data from a CEMS.
    (ii) Continuous emissions monitoring shall apply during all periods 
of operation of the coal burning equipment, including periods of 
startup, shutdown, and malfunction, except for CEMS breakdowns, 
repairs, calibration checks, and zero and span adjustments. Continuous 
monitoring systems for measuring SO2 and diluent gas shall 
complete a minimum of one cycle of operation (sampling, analyzing, and 
data recording) for each successive 15-minute period. Hourly averages 
shall be computed using at least one data point in each fifteen minute 
quadrant of an hour. Notwithstanding this requirement, an hourly 
average may be computed from at least two data points separated by a 
minimum of 15 minutes (where the unit operates for more than one 
quadrant in an hour) if data are unavailable as a result of performance 
of calibration, quality assurance, preventive maintenance activities, 
or backups of data from data acquisition and handling system, and 
recertification events. When valid SO2 pounds per hour, or 
SO2 pounds per million Btu emission data are not obtained 
because of continuous monitoring system breakdowns, repairs, 
calibration checks, or zero and span adjustments, emission data must be 
obtained by using other monitoring systems approved by the EPA to 
provide emission data for a minimum of 18 hours in each 24 hour period 
and at least 22 out of 30 successive boiler-operating-days.
    (6) Reporting and recordkeeping requirements. Unless otherwise 
stated all requests, reports, submittals, notifications, and other 
communications to the Regional Administrator required by this section 
shall be submitted, unless instructed otherwise, to the Director, 
Multimedia Planning and Permitting Division, U.S. Environmental 
Protection Agency, Region 6, to the attention of Mail Code: 6PD, at 
1445 Ross Avenue, Suite 1200, Dallas, Texas 75202-2733. For each unit 
subject to the emissions limitation in this section and upon completion 
of the installation of CEMS as required in this section, the owner or 
operator shall comply with the following requirements:
    (i) For each emissions limit in this section, comply with the 
notification, reporting, and recordkeeping requirements for CEMS 
compliance monitoring in 40 CFR 60.7(c) and (d).
    (ii) For each day, provide the total SO2 emitted that 
day by each emission unit. For any hours on any unit where data for 
hourly pounds or heat input is missing, identify the unit number and 
monitoring device that did not produce valid data that caused the 
missing hour.
    (7) Equipment operations. At all times, including periods of 
startup, shutdown, and malfunction, the owner or operator shall, to the 
extent practicable, maintain and operate the unit including associated 
air pollution control equipment in a manner consistent with good air 
pollution control practices for minimizing emissions. Determination of 
whether acceptable operating and maintenance procedures are being used 
will be based on information available to the Regional Administrator 
which may include, but is not limited to, monitoring results, review of 
operating and maintenance procedures, and inspection of the unit.
    (8) Enforcement. (i) Notwithstanding any other provision in this 
implementation plan, any credible evidence or information relevant as 
to whether the unit would have been in compliance with applicable 
requirements if the appropriate performance or compliance test had been 
performed, can be used to establish whether or not the owner or 
operator has violated or is in violation of any standard or applicable 
emission limit in the plan.
    (ii) Emissions in excess of the level of the applicable emission 
limit or requirement that occur due to a malfunction shall constitute a 
violation of the applicable emission limit.
    (b) [Reserved]

0
7. Section 52.2304 is amended by adding paragraphs (d) and (e) to read 
as follows:


Sec.  52.2304  Visibility protection.

* * * * *
    (d) Portions of SIPs addressing noninterference with measures 
required to protect visibility in any other state are disapproved for 
the 1997 PM2.5, 2006 PM2.5, 1997 ozone, 2008 
ozone, 2010 NO2 and 2010 SO2 NAAQS.
    (e) The following portions of the Texas regional haze SIP submitted 
March 19, 2009 are disapproved: The reasonable progress four-factor 
analysis, reasonable progress goals and the calculation of the emission 
reductions needed to achieve the uniform rates of progress for the 
Guadalupe Mountains and Big Bend; calculation of natural visibility 
conditions; calculation of the number of deciviews by which baseline 
conditions exceed natural visibility conditions; long-term strategy 
consultations with Oklahoma; Texas securing its share of reductions 
necessary to achieve the reasonable progress goals at Big Bend, the 
Guadalupe Mountains, and the Wichita Mountains; technical basis for its 
long-term strategy and emission limitations and schedules for 
compliance to achieve the reasonable progress goals for Big Bend, the 
Guadalupe Mountains and Wichita Mountains.

[FR Doc. 2015-31904 Filed 1-4-16; 8:45 am]
 BILLING CODE 6560-50-P


