[Federal Register Volume 81, Number 2 (Tuesday, January 5, 2016)]
[Rules and Regulations]
[Pages 295-352]
[FR Doc No: 2015-31904]

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

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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<PHONE_NUMBER>; or
<EMAIL_ADDRESS>
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

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

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

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

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).
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    \20\ 79 FR 74857.
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    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

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.
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    \21\ 79 FR 74833.
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    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.
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    \23\ 79 FR 74863.
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    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.
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    \24\ 79 FR 74863.
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    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\
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    \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.
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    \26\ 79 FR 74844.
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    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

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.
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    \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

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

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

    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\
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    \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

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.

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

    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

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),

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

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.
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    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.
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    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.
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    \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.
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    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.
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    \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.
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    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

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.
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    \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.
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    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