on Big Brown. In Texas's estimation of visibility benefits, emission
reductions at Celanese were only included in the estimation of
visibility benefits at Salt Creek (Q/d = 5.3) and Wichita Mountains (Q/
d = 8.8). The Q/d values for all other Class I areas were so low (less
than 5) that Texas assumed that no visibility benefit would result at
these Class I areas from reductions at the Celanese Chemical
Manufacturing Plant. Despite this evidence in the record of identified
cost-effective controls that result in large emission reductions and
large potential visibility benefits at multiple Class I areas, in
addition to source apportionment modeling identifying large impacts
from EGU sources, and in particular EGUs in northeast Texas, the
unreasonable manner in which the State grouped sources in weighing the
four factors resulted in controls at sources such as Big Brown, an EGU
in northeast Texas, being dismissed.
---------------------------------------------------------------------------

    \101\ The Big Brown units have a Q/d of 67.6 for Unit 1 and 69
for Unit 2 at Caney Creek in Arkansas and a Q/d of 56.9 for Unit 1
and 58.1 for Unit 2 at Wichita Mountains in Oklahoma.
---------------------------------------------------------------------------

    Additionally, the total annualized aggregate cost of $324,300,000
includes $53,500,000 associated with the cost of NOX
controls. However, visibility improvement due to reductions in nitrate
extinction are much less than the sulfate reductions at each Class I
area as shown in Table 3.

            Table 3--Texas Estimated Reduction in Extinction
------------------------------------------------------------------------
                                                     Estimated reduction
                                                     in extinction  (Mm-
                   Class I area                              1)
                                                   ---------------------
                                                     Sulfate    Nitrate
------------------------------------------------------------------------
Big Bend..........................................      0.847      0.032
Breton............................................      0.465      0.005
Caney Creek.......................................      3.232      0.054
Carlsbad Caverns..................................      1.014      0.023
Guadalupe Mountains...............................      1.014      0.023
Salt Creek........................................      1.069     -0.081
Upper Buffalo.....................................      1.583      0.016
Wheeler Peak......................................      0.121      0.000
White Mountain....................................      0.850      0.014
Wichita Mountains.................................      2.722      0.408
------------------------------------------------------------------------

    The reduction in nitrate extinction is less than 4 percent of the
sulfate reduction at each Class I area with the exception of Wichita
Mountains (15 percent). Despite this very small incremental reduction
in light extinction, Texas included costs of NOX emission
reductions, $53,500,000, in the aggregate costs for controls of which
represents more than 16 percent of the total aggregated cost of
controls. Thus, the inclusion of the costs associated with
NOX controls serves to increase the total aggregate cost but
does not result in significant visibility benefits compared to the
benefits that result for the SO2 controls.
c. Texas's Evaluation of Potential Visibility Improvements
    In considering whether compliance costs for sources were
reasonable, Texas weighed the total aggregated annual costs to the
emission reductions and estimated visibility improvement those sources
would achieve. 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,
the EPA has interpreted the CAA and the RHR as allowing States to
consider visibility alongside the four statutory factors when
determining the emission reduction measures that are necessary to make
reasonable progress. However, while it is reasonable for a State to
consider visibility benefits, it is not free to do so in a manner that
is unreasonable or inconsistent with the requirements of the CAA. For
the reasons explained in the following paragraphs, we find that Texas's
consideration of visibility improvements was unreasonable and
inconsistent with the requirements of the CAA.
i. Texas's Use of Visibility Thresholds
    The visibility thresholds selected by Texas to dismiss otherwise
meaningful visibility improvement provided for by the sources it
analyzed are inconsistent with the CAA. In evaluating and dismissing
the estimated visibility benefit from the entire control set it
identified, Texas states that the estimated benefit is not perceptible
(less than 1 dv) and that it is less than 0.5 dv, the screening
threshold used under BART requirements used to determine if a facility
contributes to visibility impairment. However, this 0.5 dv is not an
appropriate visibility threshold to use for the reasonable progress
analysis, given that the modeling inputs and metrics for determining
the visibility benefits for reasonable progress differ significantly
from modeling conducted for purposes of BART. For example, modeling
conducted for purposes of BART focused on the maximum anticipated
visibility impact from the source on a single day due to the short-term
maximum actual baseline emissions from a single facility, compared to
clean background conditions. On the other hand, the reasonable progress
analysis presented by Texas contemplates the visibility benefit to
degraded background conditions anticipated for an average tpy emission
reduction (as opposed to the impact from the total short-term maximum
emissions from the sources) averaged across the 20 percent worst days
at the Class I area(s) (which may not be the same days that are most
impacted by any particular source). By looking at average impacts over
an averaged number of days, the visibility benefits projected for a
reasonable progress analysis would be anticipated to be significantly
lower compared to maximum day impact metrics. Thus, using a 0.5 dv
threshold developed for evaluating the maximum impacts under BART as a
basis for dismissing potential controls in a reasonable progress
analysis is unreasonable. The FIP TSD associated with the 2014 Proposed
Rule provides a detailed discussion of the different metrics and
modeling typically used for BART and reasonable progress analyses.\102\
Furthermore, even in the context of BART we have stated that even
though the installation of BART may not result in a perceptible
improvement in visibility, the visibility benefit may still be
significant, as explained by the Regional Haze Rule:
---------------------------------------------------------------------------

    \102\ See Texas-Oklahoma Regional Haze FIP TSD, Appendix A,
pages A-35-A-39, A-75.

    Even though the visibility improvement from an individual source
may not be perceptible, it should still be considered in setting
BART because the contribution to haze may be significant relative to
other source contributions in the Class I area. Thus, we disagree
that the degree of improvement should be contingent upon
perceptibility.\103\
---------------------------------------------------------------------------

    \103\ 70 FR 39104, 39130 (July 6, 2005).

    As we stated in our final rule partially approving and partially
disapproving a portion of the Oklahoma Regional Haze SIP and
---------------------------------------------------------------------------
promulgating an SO2 BART FIP for Oklahoma sources:

    Given that sources are subject to BART based on a contribution
threshold of no greater than 0.5 deciviews, it would be inconsistent
to automatically rule out additional controls where the improvement
in visibility may be less than 1.0 deciview or even 0.5 deciviews. A
perceptible visibility improvement is not a requirement of the BART
determination because visibility improvements that are not
perceptible may still be determined to be significant.\104\
---------------------------------------------------------------------------

    \104\ 76 FR 81728, 81739 (Dec. 28, 2011).

    Thus, Texas's use of both perceptibility and the 0.5 dv threshold
developed for use in evaluating BART, as a basis for dismissing
potential

controls in a reasonable progress analysis is unreasonable.
ii. Visibility Benefits of Texas's Estimated Control Set
    Texas's conclusions regarding the visibility benefits of their
control set at Big Bend and Guadalupe Mountains, and its determination
that those benefits were not significant enough to justify the cost of
controls, were unreasonable.
    Texas estimated that their control set would result in 0.16 dv
visibility improvement at Big Bend. In estimating these deciview
improvements, Texas estimated that the evaluated control set would
result in a reduction in sulfate and nitrate extinction of 0.85 Mm-1
and 0.03 Mm-1, respectively.\105\ Texas only evaluated potential
controls to reduce NOX and SO2 emissions from
point sources in their four-factor analysis and Texas determined that
point sources make up over 90 percent of the projected 2018 statewide
SO2 emissions. Given the large reduction in extinction of
sulfate compared to nitrate, we focus our analysis on the projected
visibility benefits of SO2 controls. All U.S. point sources
combined were projected by CenRAP to contribute 7.19 Mm-1 in sulfate
extinction at Big Bend. Of this 7.19 Mm-1 in extinction, CenRAP
projected that Texas point sources alone would be responsible for 3.24
Mm-1, or 45 percent of the U.S. point source sulfate extinction in
2018. The next largest contribution from a State to sulfate extinction
at Big Bend is 1.10 Mm-1 from all Louisiana point sources. Thus, the
estimated visibility benefits for the Texas control set represent a 26
percent reduction in visibility impairment from sulfate due to all
Texas point sources, and a 12 percent reduction in sulfate due to all
U.S. point sources. This is a significant reduction in visibility
impairment and represents significant progress towards the national
goal of eliminating manmade visibility impairment. As we discuss
elsewhere, these potential visibility benefits of controls are impacted
by the emission baseline assumption, control efficiency assumptions,
and other factors that lead to an underestimation in the visibility
benefits due to the applied controls.
---------------------------------------------------------------------------

    \105\ Texas RH SIP Appendix 10-4b, see ``Means'' tab.
---------------------------------------------------------------------------

    For Guadalupe Mountains, Texas estimated that the evaluated control
set would result in 0.22 dv visibility improvement by securing a
reduction in sulfate and nitrate extinction of 1.01 Mm-1 and 0.02 Mm-1,
respectively. All U.S. point sources combined were projected by CenRAP
to contribute 6.78 Mm-1 in sulfate extinction at Guadalupe Mountains.
Of this 6.78 Mm-1 in extinction, CenRAP projected that Texas point
sources alone would be responsible for 3.08 Mm-1, or 45 percent of the
U.S. point source sulfate extinction in 2018. The next largest
contribution from a State to sulfate extinction at GUMO is 0.47 Mm-1
from all Louisiana point sources. The estimated visibility benefits for
the Texas control set represent a 33 percent reduction in visibility
impairment from sulfate due to all Texas point sources, and a 15
percent reduction in sulfate due to all U.S. point sources.
    Evaluating potential visibility benefits in Class I areas in nearby
States, Texas estimated that the evaluated control set would result in
0.36 dv visibility improvement at Wichita Mountains in Oklahoma. Texas
estimated that the evaluated control set would result in a reduction in
sulfate and nitrate extinction of 2.72 Mm-1 and 0.41 Mm-1, respectively
at Wichita Mountains. All U.S. point sources combined were projected by
CenRAP to contribute 21.74 Mm-1 in sulfate extinction, including 7.83
Mm-1 from Texas point sources, or 36 percent of the U.S. point source
sulfate extinction in 2018. The next largest contribution from a State
to sulfate extinction at WIMO is 2.16 Mm-1 from all Louisiana point
sources. The estimated visibility benefits for the Texas control set
represent a 35 percent reduction in visibility impairment from sulfate
due to all Texas point sources, and a 12.5 percent reduction in sulfate
due to all U.S. point sources. Similarly, the estimated visibility
benefits for the Texas control set represent a 19 percent reduction in
visibility impairment from nitrate due to all Texas point sources, and
a 7 percent reduction in nitrate due to all U.S. point sources.
    Texas failed to provide a reasonable justification for why it did
not require the control measures other than to point to the aggregate
annual cost of controls and state that the visibility benefit would not
be perceptible. However, as discussed in the previous section, Texas's
consideration of the costs was also flawed. Based on the large
percentage of contribution from Texas point sources and the amount of
visibility impairment that would be addressed under Texas's proposed
control strategy, Texas failed to adequately demonstrate that it is not
reasonable to impose control measures on those sources.
iii. Texas's Use of Degraded Background Conditions
    Texas estimated the visibility improvement of potential controls by
making comparisons to degraded background conditions instead of to
natural background conditions. However, this approach is not
reasonable, and the EPA has previously disapproved a regional haze SIP
submission for utilizing the same flawed approach. For example, North
Dakota's SIP used degraded, rather than natural background results in
what we determined to be a flawed analysis because it greatly
underestimates the visibility benefits of potential control options. As
we explained in the North Dakota SIP disapproval, this is true because
of the nonlinear nature of visibility impairment. In other words, as a
Class I area becomes more polluted, a source's contribution to changes
in impairment becomes geometrically less.\106\ In challenges to the SIP
disapproval, the 8th Circuit upheld EPA's decision to disapprove the
SIP because the SIP made comparisons to degraded background conditions
to assess visibility benefits. Specifically, the Court noted that ``the
goal of Sec.  169A is to attain natural visibility conditions in
mandatory Class I Federal areas, see 42 U.S.C. 7491(a)(1), and EPA has
demonstrated that the visibility model used by the State would serve
instead to maintain current degraded conditions.'' \107\ Because the
analysis Texas relied upon to evaluate visibility improvement uses
degraded background conditions, we propose to find Texas's
consideration and use of visibility improvement unreasonable and
inconsistent with the requirements of the CAA.
---------------------------------------------------------------------------

    \106\ 77 FR 20894, 20912 (quoting 70 FR 39124).
    \107\ North Dakota v. EPA, 730 F.3d 750, 765-66 (8th Cir. 2013).
---------------------------------------------------------------------------

d. Texas's ``Order of Magnitude Estimate'' for Visibility Improvement
    Texas produced an ``order of magnitude estimate'' of the visibility
improvements resulting from the level of aggregate emission reductions
that would result from its point source control strategy using
Particulate Matter Source Apportionment Technology (PSAT) results and
effectiveness ratios.\108\ Texas did not model the potential emission
reductions to estimate visibility benefits, but rather estimated the
benefits based on the results on the 2018 basecase CenRAP modeling and
a sensitivity run developed by CenRAP that included a large set of
emission reductions on sources throughout the CenRAP

states.\109\ This methodology assumes that all emission reductions
within a PSAT region and source category (EGU or non-EGU) have the same
effectiveness in reducing visibility impairment.\110\ For example,
emission reductions at non-EGU sources in the West Texas PSAT region
would be estimated to have the same effect on visibility, regardless of
location, like the Big Spring facility (330 km to Guadalupe Mountains)
and the Borger facility (524 km to Guadalupe Mountains). The estimated
effectiveness factor applied equally to all emission reductions at EGUs
located in the East Texas source region, including Sommers Deely Spruce
(440 km from Big Bend and 680 km from Guadalupe Mountains) and
Monticello (850 km from Big Bend and 920 km from Guadalupe Mountains).
Given the large difference in distances between these two facilities
and the Class I areas, it is reasonable to expect that the
effectiveness of emission reductions could vary greatly between the
two. We propose to find that given the variability in the distances
between sources and Class I areas, it was unreasonable for Texas not to
consider how its assumptions could result in underestimation of the
visibility benefit of controlling the sources it selected for
consideration in its four-factor analysis.
---------------------------------------------------------------------------

    \108\ The Comprehensive Air Quality Model with extensions (CAMx)
with PSAT is a tool used to provide source apportionment of
particulate matter species from primary sources to defined receptor
locations by geographic region and major source category.
    \109\ See Texas RH SIP Appendix 10-2 and 10-4.
    \110\ For PSAT modeling and control analysis, Texas was divided
into 3 regions (East Texas, West Texas, and Texas Gulf Coast). See
Figure 5-8 of Technical Support Document for CenRAP Emissions and
Air Quality Modeling to Support Regional Haze State Implementation
Plans (CenRAP TSD), available in the docket for this action under
Document ID EPA-R06-OAR-2014-0754-0014.
---------------------------------------------------------------------------

C. Clarification of Our Basis for Disapproval of Texas's Calculation of
Natural Visibility Conditions

    We are proposing to disapprove Texas's calculation of natural
visibility conditions. Section 51.308(d)(2)(iii) requires States to
calculate the natural visibility conditions for each Class I area
located within the State by estimating the degree of visibility
impairment existing under natural conditions for the most impaired and
least impaired days, based on available monitoring information and
appropriate data analysis techniques.
    We explained the basis for our disapproval of Texas's calculation
of the natural visibility conditions for the Guadalupe Mountains and
Big Bend in the preamble of our 2014 Proposed Rule and in the preamble
of our 2016 Final Rule.\111\ While not specifically addressed in the
2016 stay opinion, statements made by the Fifth Circuit motions panel
appear to indicate disagreement with the EPA's disapproval of Texas's
calculation of natural visibility conditions at the Guadalupe Mountains
and Big Bend. Specifically, the court's opinion stated that the RHR
grants States considerable flexibility when they estimate natural
conditions and that EPA's natural visibility guidance expressly permits
States to use refined approaches for the calculation of natural
visibility and to identify other approaches that are more appropriate
for their own situations. We agree that our guidance and the RHR allow
states to develop an alternative approach to estimate natural
visibility conditions.\112\ The fact that States have the option of
calculating their own natural visibility conditions instead of using
the default natural conditions provided in the guidance is not at
issue. However, any such alternative approach must be supported and
documented. As we state in our guidance, 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.'' \113\ Texas did not provide a technically and scientifically
supportable approach, specifically by not adequately supporting the
assumptions used in calculating ``refined'' estimates of natural
visibility conditions.
---------------------------------------------------------------------------

    \111\ 79 FR at 74830-74832 (2014 Proposed Rule) and 81 FR at
299-300, 325-326 (2016 Final Rule).
    \112\ Guidance for Estimating Natural Visibility Conditions
Under the Regional Haze Rule, EPA-454/B-03-005, September 2003. See
also 51.308(d)(2)(iii).
    \113\ Guidance for Estimating Natural Visibility Conditions
Under the Regional Haze Rule, EPA, September 2003, at 1-11.
---------------------------------------------------------------------------

    One alternative approach available to States is to develop and
justify the use of alternative estimates of natural concentrations of
fine particle components. Another option available to States is to use
the ``new IMPROVE equation'' that was adopted for use by the IMPROVE
Steering Committee in December 2005.\114\ This refined version of the
IMPROVE equation provided more accurate estimates (as compared to the
``old IMPROVE equation'') of some of the factors that affect the
calculation of light extinction. The default natural conditions in our
guidance \115\ 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.116 117 These estimates are
referred to as the ``NCII'' default natural visibility conditions.
---------------------------------------------------------------------------

    \114\ The IMPROVE program is a cooperative measurement effort
governed by a steering committee composed of representatives from
Federal agencies (including representatives from EPA and the federal
land managers) and regional planning organizations. The IMPROVE
monitoring program was established in 1985 to aid the creation of
Federal and State implementation plans for the protection of
visibility in Class I areas. One of the objectives of IMPROVE is to
identify chemical species and emission sources responsible for
existing anthropogenic visibility impairment. The IMPROVE program
has also been a key participant in visibility-related research,
including the advancement of monitoring instrumentation, analysis
techniques, visibility modeling, policy formulation and source
attribution field studies.
    \115\ Guidance for Estimating Natural Visibility Conditions
Under the Regional Haze Rule, EPA-454/B-03-005, September 2003.
    \116\ Pitchford, Marc, 2006, Natural Haze Levels II: Application
of the New IMPROVE Algorithm to Natural Species Concentrations
Estimates. Final Report of the Natural Haze Levels II Committee to
the RPO Monitoring/Data Analysis Workgroup. September 2006,
available at: https://vista.cira.colostate.edu/improve/Publications/GrayLit/029_NaturalCondII/naturalhazelevelsIIreport.ppt.
    \117\ The second version of the natural haze level II estimates
based on the work of the Natural Haze Levels II Committee is
available at: https://vista.cira.colostate.edu/Docs/IMPROVE/Aerosol/NaturalConditions/NaturalConditionsII_Format2_v2.xls.
---------------------------------------------------------------------------

    Texas chose to derive a ``refined'' estimate of natural visibility
conditions rather than using the default NCII values.\118\ In
calculating natural visibility conditions, Texas used the new IMPROVE
equation and PM concentration estimates (i.e., the NCII values) for
most components, but assumed that 100 percent of the fine soil and
coarse mass concentrations in the baseline period is attributed to
natural causes and that the corresponding estimates in the NCII values
should be replaced. Texas did so without adequately demonstrating that
all fine soil and coarse mass measured in the baseline period can be
attributed to 100 percent natural sources. Anthropogenic sources of
coarse mass and fine soil in the baseline period could have included
emissions associated with paved and unpaved roads, agricultural
activity, and construction activities as well. We also note that the
impact from dust at Big Bend is less certain than at the Guadalupe
Mountains and a different assumption may be appropriate in estimating
natural conditions there. Furthermore, Texas itself concluded that it
cannot verify its own assumption that all fine soil and coarse mass
measured in the baseline period can be attributed to 100 percent
natural sources. Texas acknowledged that the information it cites to in
the Texas Regional Haze SIP does not quantify the percentage of
anthropogenic or natural

contributions to total coarse mass and fine dust, and that some portion
must be from human activity.\119\ We are proposing to disapprove
Texas's calculation of natural visibility conditions for the Guadalupe
Mountains and Big Bend because those calculations are based on the
technically indefensible assumption that there is 0 percent dust (CM
and soil) from human activity when Texas rightly concedes that some
impairment ``must be from some human activity.'' \120\
---------------------------------------------------------------------------

    \118\ See Chapter 5 and Appendix 5-2 of the Texas Regional Haze
SIP.
    \119\ Appendix 5-2 of the Texas Regional Haze SIP at page 4
Texas states in its SIP that ``while some dust (CM and Soil) at both
of Texas' Class I areas must be from some human activity, the times
when human caused dust is likely to be more important at these sites
are on days with less visibility impairment than on the worst dust
impaired days.'' Texas goes on to conclude that ``for the sake of
the most and least impaired natural visibility estimates, to treat
100 percent of the CM and Soil concentrations measured at each of
its Class I areas as natural.'' See id.
    \120\ See Appendix 5-2 of the Texas Regional Haze SIP at page 4.
---------------------------------------------------------------------------

D. Clarification of Our Basis for Disapproval of Consultation Between
Texas and Oklahoma

    In finalizing the RHR, we stated that ``successful implementation
of the regional haze program will involve long term regional
coordination among States,'' and that ``States will need to develop
strategies in coordination with one another, taking into account the
effect of emissions from one jurisdiction to air quality in another.''
\121\ We also noted that RPGs and long-term strategies are intricately
linked.\122\ The regulations bear this out. Section 51.308(d)(3)(i)
requires that States (in this case Texas) consult with other States if
its emissions are reasonably anticipated to contribute to visibility
impairment at that State's Class I area(s), and that Texas consult with
other States if those States' emissions are reasonably anticipated to
contribute to visibility impairment at the Guadalupe Mountains and Big
Bend. We commonly refer to this as the long-term strategy consultation.
Similarly, in developing the RPGs for its Class I area(s), Section
51.308(d)(1)(iv) requires that States (in this case Oklahoma) consult
with those States which may reasonably be anticipated to cause or
contribute to visibility impairment at their Class I area(s) (in this
case Wichita Mountains). We commonly refer to this as the reasonable
progress consultation. Section 51.308(d)(3)(ii) requires that if a
State's emissions (in this case Texas's 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)(iii) requires that
States (in this case Texas) 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. This documentation is necessary so that the interstate
consultation process can proceed on an informed basis, and so that
downwind states can properly assess whether any additional upwind
emission reductions are necessary to achieve reasonable progress at
their Class I area(s).
---------------------------------------------------------------------------

    \121\ 64 FR 35714, 35728 (July 1, 1999).
    \122\ 64 FR at 35735 (July 1, 1999).
---------------------------------------------------------------------------

    We explained the basis for our disapproval of Texas's consultation
with Oklahoma to address visibility impairment in the Wichita
Mountains, as required under section 51.308(d)(3)(i), in the preamble
of our 2014 Proposed Rule and in the preamble of our 2016 Final
Rule.\123\ We also explained the basis for our disapproval of
Oklahoma's consultation with Texas to address visibility impairment in
the Wichita Mountains, as required under section 51.308(d)(1)(iv), in
the preamble of our 2014 Proposed Rule and in the preamble of our 2016
Final Rule.\124\ As to EPA's disapproval of the consultation between
Texas and Oklahoma, the Fifth Circuit motions panel in the 2016 stay
opinion stated that ``EPA's disapproval seems to stem in large part
from its assertion that Texas had to conduct a source-specific analysis
and provide Oklahoma with that source-specific analysis.'' \125\ This
is incorrect. The basis for our disapproval of Texas's long-term
strategy consultation with Oklahoma was not, and is not, tied to
whether Texas conducted a source-specific analysis and provided
Oklahoma with that source-specific analysis. Rather, we are proposing
to disapprove Texas's long-term strategy consultation with Oklahoma
because it relied on and was informed by a flawed four-factor analysis
in which Texas analyzed and weighed the four reasonable progress
factors in a manner that is unreasonable and inconsistent with the
requirements of the CAA and the RHR. Similarly, we are proposing to
disapprove Oklahoma's reasonable progress consultation with Texas and
the RPG Oklahoma established for the Wichita Mountains. Oklahoma
unreasonably relied on and was informed by Texas's flawed four-factor
analysis that concluded no additional control measures were necessary
even though both States acknowledged Wichita Mountains suffers from
``significant anthropogenic impacts from Texas'' \126\ and cost-
effective controls were available. Given that impacts from Texas point
sources were several times greater than the impact from Oklahoma's own
point sources, Oklahoma and Texas did not adequately justify why
additional reductions from Texas sources were not necessary to address
impacts at the Wichita Mountains as part of the consultation process
required under the RHR.
---------------------------------------------------------------------------

    \123\ 79 FR at 74854-74856 (2014 Proposed Rule) and 81 FR at
300-301, 312-313 (2016 Final Rule).
    \124\ 79 FR 74818, 74864-74872 (2014 Proposed Rule) and 81 FR
302-303, 312-313, 338, 339-343 (2016 Final Rule).
    \125\ Texas, 829 F. 3d at 428.
    \126\ See August 3, 2007 letter from ODEQ Executive Director
Steven Thompson to TCEQ Executive Director Glenn Shankle included in
Appendix 4-2 of Texas Regional Haze SIP.
---------------------------------------------------------------------------

    In determining its long-term strategy under section
51.308(d)(3)(iii), we believe that Texas had an obligation to conduct
an appropriate technical analysis and demonstrate through that
technical analysis (required under section 51.308(d)(3)(ii)), that it
provided its fair share of emission reductions to Oklahoma. Texas used
its flawed four-factor analysis to determine its ``share of the
emission reductions needed to meet the progress goal'' for the Wichita
Mountains and to inform its decision not to control any additional
sources, including those that impact visibility at the Wichita
Mountains. To the extent that Texas relied on its flawed four-factor
analysis to address the requirements of section 51.308(d)(3)(ii) and
51.308(d)(3)(iii), it did not develop and provide the information
necessary to determine the reasonableness of controls at those sources
in Texas that impact visibility at the Wichita Mountains or other Class
I areas. For the same reasons discussed in this section regarding the
bases for our disapproval of Texas's four-factor analysis, we are
proposing to find that Texas's demonstration failed to satisfy the
requirements under section 51.308(d)(3)(ii) and section
51.308(d)(3)(iii).
    CenRAP source apportionment modeling results indicated that Texas
is a significant contributor to visibility impairment at the Wichita
Mountains.\127\ Point sources are the most significant contributors to
haze at the Wichita Mountains, and the largest contributing point
sources are Texas

EGUs. Texas SO2 emissions were projected in 2018 to have the
largest visibility impacts, in terms of both absolute contribution to
extinction and percent contribution to total extinction, at the Wichita
Mountains in Oklahoma. Table 4 summarizes the percent of visibility
impairment at the Wichita Mountains from Oklahoma and nearby states
projected in 2018 based on the CenRAP modeling results.\128\
---------------------------------------------------------------------------

    \127\ See Appendix E of the Technical Support Document for
CENRAP Emissions and Air Quality Modeling to Support Regional Haze
SIP, included as Appendix 8-1 of the Texas Regional Haze SIP.
    \128\ These model results include estimated reductions due to
the implementation of CAIR, other on-the-book federal and State
rules, and some assumptions for BART reductions in Oklahoma and
other states.

                                Table 4--Percent Contribution to Total Visibility Impairment at Wichita Mountains in 2018
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                Eastern  U.S.
                                            Texas  (%)     Oklahoma  (%)  Louisiana  (%)    Kansas  (%)    Arkansas  (%)   Missouri  (%)        (%)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Percent Total Contribution, All                     27.5            16.3             4.8             3.8             2.3             2.8             4.2
 Pollutants.............................
Percent Point Source Contribution, All              14.0             3.9             3.4             1.4             1.3             1.7             3.2
 Pollutants.............................
--------------------------------------------------------------------------------------------------------------------------------------------------------

    Texas (all sources and pollutants) is projected to contribute 27.5
percent of the visibility impairment at the Wichita Mountains, compared
to 16.3 percent for Oklahoma sources, 4.8 percent from Louisiana
sources and 4.2 percent from sources in the Eastern U.S. Point sources
in Texas are projected to account for 14 percent of all visibility
impairment projected in 2018 at Wichita Mountains, compared to 3.9
percent from Oklahoma point sources, 3.4 percent from Louisiana point
sources and 3.2 percent from point sources in the Eastern U.S.
    Oklahoma and Texas mutually acknowledged that Texas sources
significantly impact visibility at the Wichita Mountains in Oklahoma,
and that the impacts from point sources in Texas are several times
greater than the impact from Oklahoma point sources.\129\ Furthermore,
Oklahoma asserted in its consultations with Texas, and elsewhere in the
Oklahoma Regional Haze SIP, that the Wichita Mountains would remain
above the URP without additional reductions from Texas sources. During
consultation calls with Texas and other states, Oklahoma specifically
requested additional information on feasibility and cost of controls
for those facilities identified through the CenRAP process as having
available controls estimated to cost less than $5,000/ton and with the
potential to result in visibility improvements in the Wichita Mountains
due to their location and emissions.\130\ The cost-effectiveness of all
the Texas point sources identified by Oklahoma except one was below
$3,000/ton. Texas relied on the cost estimates developed by CenRAP and
shared with Oklahoma with respect to feasibility and costs of potential
controls for which Oklahoma specifically requested information. Texas
also identified that there is uncertainty in the size and distribution
in emissions in the future projections and that no EGUs made an
enforceable commitment to any particular pollution control strategy and
preferred to retain the flexibility offered by the CAIR program.\131\
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    \129\ See e.g., March 25, 2008 letter from TCEQ Air Quality
Division Director Susana M. Hildebrand, P.E., to ODEQ Air Quality
Division Director Eddie Terrill included in Appendix 4-2 of Texas
Regional Haze SIP.
    \130\ See document entitled, ODEQ Wichita Mountains consultation
(Aug. 16, 2007), available in the docket for this action under
Document ID EPA-R06-OAR-2014-0754-0030.
    \131\ See Texas Regional Haze SIP at section 10.5.
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    In addition, Texas provided Oklahoma with information that other
sources with existing controls still have a large potential to impact
visibility and should be analyzed for control upgrades. Specifically,
Texas provided Oklahoma a letter on March 25, 2008, which included a
table that listed sources of ``particular interest to Wichita Mountains
due to their emissions and their positions within the area of
influence.'' \132\ However, Texas did not analyze the costs of controls
or corresponding visibility benefits of several of these sources even
though they identified them as a source of interest. Some of these
sources include EGUs at Martin Lake and Pirkey. In the case of Martin
Lake, the three units combined were projected to emit over 35,000 tpy
of SO2. SO2 emissions from the Pirkey facility
were projected to be over 19,000 tpy. Given Texas's identification of
these sources, it was unreasonable for Texas not to provide any further
analysis and Texas and Oklahoma did not adequately justify why
additional reductions from these sources were not necessary to address
impacts at the Wichita Mountains as part of the consultation process
required under the RHR.
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    \132\ March 25, 2008 letter from TCEQ Air Quality Division
Director Susana M. Hildebrand, P.E., to ODEQ Air Quality Division
Director Eddie Terrill included in Appendix 4-2 of Texas Regional
Haze SIP.
---------------------------------------------------------------------------

    Ultimately, Texas determined that no additional controls at its
sources were warranted during the first planning period to help achieve
reasonable progress at the Wichita Mountains, and Oklahoma did not
specifically request any additional reductions from Texas sources. As a
result, Oklahoma established RPGs for the Wichita Mountains that do not
reflect any reasonable emission reductions from Texas beyond those that
will be achieved by compliance with other requirements of the CAA. We
are proposing to disapprove Texas's long-term strategy consultation
with Oklahoma required under Section 51.308(d)(3)(i) because it relied
on and was informed by Texas's flawed four-factor analysis, as
discussed in Section V.B. Similarly, Oklahoma's reasonable progress
consultation with Texas required under Section 51.308(d)(1)(iv) and the
RPG Oklahoma established for the Wichita Mountains relied on Texas's
flawed four-factor analysis. We are proposing to disapprove those
portions of Oklahoma's Regional Haze SIP because they relied on and
were informed by Texas's flawed four-factor analysis, as discussed in
Section V.B. For the same reasons, we are proposing to find that
Texas's demonstration failed to satisfy the requirements under section
51.308(d)(3)(ii) and section 51.308(d)(3)(iii).

VI. Amending the FIP on Remand

    We are proposing to amend the 2016 FIP by proposing to find that no
further federal action is needed to remedy the disapprovals of portions
of the Texas and Oklahoma Regional Haze SIPs. We are proposing to not
make changes to our recalculation in the 2016 FIP of the natural
visibility conditions on the 20 percent best and worst days for the
Guadalupe Mountains and Big Bend. We are also proposing to not make

changes to our recalculation in the 2016 FIP of the following metrics
that are dependent on the calculation of the natural visibility
conditions: the number of deciviews by which baseline visibility
conditions exceed natural visibility conditions for the Guadalupe
Mountains and Big Bend (i.e., our calculation of visibility impairment)
pursuant to section 51.308(d)(2)(iv)(A) and our recalculation of the
URPs for the 20 percent worst days for these Class I areas.
    We are proposing to rescind the SO2 emission limits
established in the 2016 FIP. Our 2016 FIP required SO2
emission limits for 15 coal-fired EGUs at eight power plants that
affect visibility at the Wichita Mountains Wilderness, Big Bend
National Park, and Guadalupe Mountains National Park. We required
emission limits consistent with scrubber upgrades and a compliance date
three years from the effective date of the 2016 Final Rule on the
following units: (1) Monticello 3; (2) Sandow 4; (3) Martin Lake Units
1, 2, and 3; and (4) Limestone Units 1 and 2. We further required
emission limits consistent with scrubber retrofits and a compliance
date five years from the effective date of the 2016 Final Rule on the
following units: (1) Big Brown Units 1 and 2; (2) Monticello Units 1
and 2; (3) Coleto Creek Unit 1; and (4) Tolk Units 171B and 172B.
Finally, we required an SO2 emission limit for the San
Miguel unit based on the continued operation of scrubber upgrades it
had already installed, which the facility needed to comply with within
one year from the effective date of the 2016 Final Rule.
    On remand, we revisited whether, in light of the Fifth Circuit's
2016 stay opinion, as well as several changes in circumstances, the FIP
should remain or be amended. In the interim period between the 2016
Final Rule and this proposal, several units for which we promulgated
emission limits in the 2016 Final Rule have shut down. These units are:
Sandow 4; \133\ Monticello Units 1, 2, and 3; \134\ and Big Brown Units
1 and 2.\135\ These shutdowns are permanent and enforceable because the
CAA permits for these units have been voided. These units may not
return to operation without going through CAA new source review
permitting and Title V operating permitting requirements. Therefore,
the EPA is proposing to rescind the SO2 emission limits for
these units.
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    \133\ See letter dated February 14, 2018, from Kim Mireles of
Luminant to the TCEQ requesting to cancel certain air permits and
registrations for Sandow Steam Electric Station available in the
docket for this action.
    \134\ See letter dated February 8, 2018, from Kim Mireles of
Luminant to the TCEQ requesting to cancel certain air permits and
registrations for Monticello available in the docket for this
action.
    \135\ See letter dated March 27, 2018, from Kim Mireles of
Luminant to the TCEQ requesting to cancel certain air permits and
registrations for Big Brown available in the docket for this action.
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    Furthermore, several units, including Martin Lake Units 1, 2, and
3, and Coleto Creek Unit 1 may be subject to emission limits under our
proposed BART FIP for Texas EGUs.\136\ If finalized, these emission
limits will provide for similar emission reductions and visibility
improvement that would have been achieved by the emission limits for
these units in the 2016 FIP. Therefore, we propose to find that no
further controls beyond BART should be required for Martin Lake Units
1, 2, and 3, and Coleto Creek Unit 1, and we propose to rescind the
SO2 emission limits for these units.
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    \136\ See 88 FR 28918, 28977 (May 4, 2023). In addition to the
units listed at Martin Lake and Coleto Creek, the 2023 Texas BART
action proposed emission limits for three units at the W.A. Parish
facility, two units at the Harrington facility, two units at the
Fayette facility, and one unit at the Welsh facility. We anticipate
finalizing the proposed 2023 Texas BART action before finalizing
this proposed Reasonable Progress action.
---------------------------------------------------------------------------

    After taking into account the Texas EGUs that have permanently shut
down in the intervening period and those that are subject to proposed
controls under our recently proposed Texas BART FIP, the remaining
units for which we required SO2 limits in the 2016 FIP are
Limestone Units 1 and 2; Tolk Units 171B and 172B; and San Miguel Unit
1. With respect to these units, the EPA is proposing to rescind the
SO2 emission limits. As explained above, several units in
Texas have shut down and the EPA recently proposed BART emission limits
for 12 units in Texas. Additionally, we took a voluntary remand on the
2016 Final Rule, in part, due to the motion panel's finding in its stay
opinion of the petitioners' likelihood of success on the merits. As to
the SO2 emission limits imposed by the FIP portion of the
2016 Final Rule, the panel found that the EPA likely did not have the
authority to impose controls that could not be installed until after
the end of the planning period (in this case, beyond the end of the
first planning period, or 2018). We strongly disagree with the panel's
view that the RHR somehow constrains States or the EPA from imposing
controls that cannot be installed until after the end of the planning
period. Nevertheless, in response to the panel's opinion, we revised
the Regional Haze Rule in 2017 to clarify that for the second and
subsequent planning periods, states or the EPA can require controls
even if they cannot be installed until after the end of the planning
period.\137\ In addition, we previously found that San Miguel upgraded
its SO2 scrubber system in 2010, 2011, 2012, and 2014 to
perform at the reasonably highest level that can be expected
(approximately 94 percent SO2 removal efficiency) based on
the extremely high sulfur content of the coal being burned and the
technology available.\138\ In the 2016 FIP, we finalized an
SO2 emission limit based on the continued operation of the
scrubber upgrades the facility had already performed and consistent
with recent monitoring data.\139\ As a result, we did not anticipate
that San Miguel would have to install any additional controls in order
to comply with the SO2 emission limit we finalized.\140\ The
scrubber upgrades at San Miguel remain in place, and we do not
anticipate any increase in visibility impacts from the unit.
---------------------------------------------------------------------------

    \137\ See 40 CFR 51.308(f)(2)(i).
    \138\ See ``Technical Support Document for the Cost of Controls
Calculations for the Texas Regional Haze Federal Implementation Plan
(Cost TSD)'' dated November 2014, pages 56-61. This is the Cost TSD
for the 2016 Texas-Oklahoma RP FIP and is available in the docket
for this action under Document ID EPA-R06-OAR-2014-0754-0008.
    \139\ 79 FR at 74823 (footnote 26) and 81 FR at 332 (footnote
161).
    \140\ 81 FR at 305.
---------------------------------------------------------------------------

    We propose to find that for these reasons, no additional emission
limits are necessary to make reasonable progress for the first planning
period. The EPA will also have an opportunity to evaluate Texas's
analyses and determinations for the Texas second planning period
SIP,\141\ including with respect to Limestone, Tolk, and San Miguel.
Because we are proposing to rescind the emission limits promulgated in
the 2016 FIP for the reasons explained in the preceding paragraphs, we
are proposing that it is not necessary to revise our four-factor
analysis.
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    \141\ On July 20, 2021, Texas submitted its second planning
period Regional Haze SIP to the EPA. See ``2021 Regional Haze SIP
Revision'' at https://www.tceq.texas.gov/airquality/sip/bart/haze_sip.html.
---------------------------------------------------------------------------

    While we are proposing to rescind the SO2 emission
limits established in the 2016 FIP, we are proposing that it is not
necessary to revise the 2018 RPGs we calculated in the 2016 FIP.
Section 169B(e)(1) of the CAA directed EPA to promulgate regulations
that ``include[e] criteria for measuring `reasonable progress' toward
the national goal.'' Consequently, the regional haze regulations for
the first planning period direct states to develop RPGs for the most
and least impaired days to ``measure'' the progress that will be
achieved by the control measures in the

state's long-term strategy ``over the period of the implementation
plan.'' \142\ The RPGs represent the best estimate of the degree of
visibility improvement that is anticipated to result in the Class I
area at the end of the planning period taking into account the measures
included in the long-term strategy over the period of the SIP for that
planning period. For the first planning period, the RPGs allow for
comparisons between the progress that will be achieved by the state's
long-term strategy and the URP,\143\ and provide a benchmark for
assessing the adequacy of a state's SIP in 5-year periodic
reports.\144\ In the 2016 FIP, we calculated new 2018 RPGs for the 20
percent worst days and the 20 percent best days for the Guadalupe
Mountains, Big Bend, and the Wichita Mountains based on our technical
analysis in that FIP.\145\ However, it is now five years past the end
of the first planning period. Given the timing of this action, revising
the RPGs for 2018 would not further the purpose or intent behind
establishing the RPGs for the first planning period. Furthermore, as we
discussed in the preceding paragraphs, in a separate proposed rule
recently published in the Federal Register,\146\ we proposed
SO2 emission limits for 12 Texas EGUs under the BART
requirements, some of which are the same EGUs for which we promulgated
SO2 emission limits in the 2016 FIP. Additionally, several
Texas EGUs have shut down including some of the same units addressed in
the 2016 FIP. In evaluating the Texas and Oklahoma Regional Haze SIPs
for the second planning period,\147\ we will have an opportunity to
evaluate these States' four-factor analyses for the second planning
period, including the 2028 RPGs adopted by the States. For these
reasons, we are proposing to find that it is not necessary or practical
at this point in time for the EPA to make further changes to the 2018
RPGs.
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    \142\ 40 CFR 51.308(d)(1).
    \143\ 40 CFR 51.308(d)(1)(ii).
    \144\ 40 CFR 51.308(g)-(h).
    \145\ 81 FR at 347, see Table 9.
    \146\ See 88 FR 28918 (May 4, 2023).
    \147\ Texas submitted its Regional Haze SIP for the second
planning period to EPA on July 20, 2021, and Oklahoma submitted its
Regional Haze SIP for the second planning on August 9, 2022.
---------------------------------------------------------------------------

    As described in further detail below, we find that the EPA's
proposed revision to the FIP would not result in interference with any
applicable CAA requirements and would be consistent with CAA section
110(l). We note that, on the face of this action, the rescission of the
emission limits could lead to increases in emissions of SO2
over what was anticipated in the 2016 Final Rule. The 2016 FIP imposed
emission limits on 15 EGUs located at eight different facilities.
However, since that action was promulgated, six of the EGUs covered by
the 2016 FIP have permanently shut down and retired. Due to these
shutdowns, there are no longer emissions from these six EGUs. As a
result, the proposed rescission of these SO2 emission limits
will have no effect, and the emissions from these sources will be lower
than anticipated in the 2016 FIP. In addition, the EPA recently
proposed source-specific BART limits for four of these EGUs that, if
finalized, would impose similar limitations on SO2
emissions.
    For the remaining five EGUs (two EGUs located at the Limestone
facility, two EGUs located at the Tolk facility, and one EGU located at
San Miguel facility),\148\ the proposed rescission of the emission
limits, which were judicially stayed from taking effect, is not
anticipated to interfere with any applicable requirements under the
CAA. First, the geographic areas where the five EGUs are located are
not part of a nonattainment area for any National Ambient Air Quality
Standards (NAAQS).\149\ The Limestone facility is located in a county
adjacent to the Freestone/Anderson SO2 nonattainment area.
However, at the time the EPA designated this area as nonattainment, we
used dispersion modeling to identify nearby areas that contributed to
the violation of the NAAQS.\150\ Based on this evaluation, we found
that emissions from the Limestone facility did not contribute to the
violation of the SO2 NAAQS. Additionally, since that time,
the Big Brown facility, which was the primary source causing the NAAQS
violations in the Freestone/Anderson SO2 nonattainment area,
has shut down, and the EPA made a Clean Data Determination in 2021
finding that the area is currently attaining the 1-hour SO2
NAAQS.\151\
---------------------------------------------------------------------------

    \148\ The SO2 emission limit we are proposing to
rescind for the San Miguel facility is based on SO2
scrubber system upgrades that the facility had already installed
prior to the promulgation of the 2016 FIP. The SO2
emission limit we required for San Miguel was based on the emission
rate the facility was already meeting and thus we do not expect that
our proposed rescission of this emission limit would result in an
increase in SO2 emissions from this facility.
    \149\ The Limestone facility is located in Limestone County, the
Tolk facility is located in Lamb County, and the San Miguel facility
is located in Atascosa County. None of these counties are part of a
nonattainment area for any NAAQS.
    \150\ See Technical Support Document for the Designation
Recommendations for the 2010 Sulfur Dioxide National Ambient Air
Quality Standards (NAAQS)--Supplement for Four Areas in Texas Not
Addressed in June 30, 2016, Version, Docket No EPA-HQ-OAR-2014-0464,
at pg. 15-16 (Nov. 29, 2016), available in the docket for this
action.
    \151\ 86 FR 26401 (May 14, 2021).
---------------------------------------------------------------------------

    Second, there are no approved attainment demonstrations in other
areas of the State or outside of the state that rely on the
SO2 emission limits for these five EGUs to achieve
attainment of any of the NAAQS. At this time, the areas that may be
potentially impacted by our rescission of the SO2 emission
limits for Limestone, Tolk, and San Miguel are all attaining the 2010
1-hour SO2 NAAQS, 2006 PM2.5 NAAQS, and 2012
PM2.5 NAAQS.152 153 Additionally, rescinding the
emission limits will not alter how these sources have been operating
and thus the EPA does not anticipate that emission levels from these
sources will increase such that we would expect exceedances of, or
interference with, the SO2 and PM2.5 NAAQS to
occur in the future in the areas where these sources are located.
---------------------------------------------------------------------------

    \152\ Since SO2 is a precursor pollutant for fine
particulate matter (PM2.5), we also address whether
withdrawal of the FIP emission limits would interfere with
attainment of the PM2.5 NAAQS.
    \153\ As we noted in the final rule promulgating the 2010 1-hour
SO2 NAAQS, a significant fact for ambient SO2
concentrations is that stationary sources are the predominant
emission sources of SO2 and the peak, maximum
SO2 concentrations that may occur are most likely to
occur nearer the parent stationary source. 75 FR 35520, 35557 (June
22, 2010).
---------------------------------------------------------------------------

    Finally, the proposed rescission of the FIP provisions would not
interfere with the ``applicable requirements'' of the regional haze
program. This section explains how the proposed FIP revision will
comply with applicable regional haze requirements and general
implementation plan requirements. As such, our rescission of these FIP
provisions will not interfere with the CAA requirements for regional
haze, including the reasonable progress and long-term strategy
provisions of the regional haze program.

VII. Proposed Action

    We are proposing disapproval of the portions of the Texas Regional
Haze SIP and Oklahoma Regional Haze SIP we previously disapproved in
our 2016 Final Rule.
    With respect to the Texas Regional Haze SIP, we are proposing
disapproval of the portions of the Texas Regional Haze SIP addressing
the following Regional Haze Rule requirements contained in 40 CFR part
51: \154\
---------------------------------------------------------------------------

    \154\ We are also proposing disapproval of 30 TAC 116.1510(d).
---------------------------------------------------------------------------

     Section 51.308(d)(1) regarding the RPGs for the Guadalupe
Mountains and Big Bend;
     Section 51.308(d)(1)(i)(A) regarding the four-factor
analysis;

     Section 51.308(d)(1)(i)(B) regarding the requirement to
calculate the emission reduction measures needed to achieve the URP for
the Guadalupe Mountains and Big Bend for the period covered by the SIP;
     Section 51.308(d)(1)(ii) regarding the requirement to
demonstrate, based on the factors in Section 51.308(d)(1)(i)(A), that
the progress goal adopted by Texas is reasonable;
     Section 51.308(d)(2)(iii) regarding the calculation of
natural visibility conditions for the Guadalupe Mountains and Big Bend
for the most impaired and least impaired days;
     Section 51.308(d)(2)(iv)(A) regarding the calculation of
the number of deciviews by which baseline conditions exceed natural
visibility conditions for the Guadalupe Mountains and Big Bend for the
most impaired and least impaired days;
     Section 51.308(d)(3)(i) regarding Texas's long-term
strategy consultations with Oklahoma in order to develop coordinated
emission management strategies to address visibility impacts at the
Wichita Mountains;
     Section 51.308(d)(3)(ii) regarding the requirement for
Texas to secure its share of reductions necessary to achieve the RPGs
for the Guadalupe Mountains, Big Bend, and the Wichita Mountains;
     Section 51.308(d)(3)(iii) regarding the requirement for
Texas to document the technical basis for its long-term strategy for
the Guadalupe Mountains, Big Bend, and the Wichita Mountains;
     Section 51.308(d)(3)(v)(C) regarding Texas's emission
limitations and schedules for compliance to achieve the RPGs for the
Guadalupe Mountains, Big Bend, and the Wichita Mountains.
    We are also proposing disapproval of the portions of the Oklahoma
Regional Haze SIP addressing the following Regional Haze Rule
requirements contained in 40 CFR part 51:
     Section 51.308(d)(1) regarding the RPGs for the Wichita
Mountains;
     Section 51.308(d)(1)(i)(A) regarding the four-factor
analysis;
     Section 51.308(d)(1)(i)(B) regarding the requirement to
consider the URP for the Wichita Mountains and the emission reduction
measures needed to achieve it for the period covered by the SIP;
     Section 51.308(d)(1)(ii) regarding the requirement to
demonstrate, based on the factors in Section 51.308(d)(1)(i)(A), that
the rate of progress for the SIP to attain natural conditions by 2064
is not reasonable and that the progress goal adopted by Oklahoma is
reasonable;
     Section 51.308(d)(1)(iv) regarding the requirement for
Oklahoma to consult with Texas with respect to the visibility impact of
Texas sources at the Wichita Mountains.
    We are proposing to find that no further federal action is needed
to remedy the proposed disapprovals of these portions of the Texas and
Oklahoma Regional Haze SIPs. We are proposing to rescind the
SO2 emission limitations and the associated monitoring,
reporting, and recordkeeping requirements we established in the 2016
FIP for Texas EGUs. We are also proposing that it is not necessary to
revise the four-factor analysis or the numeric 2018 RPGs we established
in the 2016 FIP for the Guadalupe Mountains, Big Bend, and the Wichita
Mountains. Finally, we are proposing to find that our amendments to the
2016 FIP are consistent with CAA section 110(l) because they will not
interfere with any applicable requirement concerning attainment or
reasonable further progress (as defined in section 7501 of this title),
or any other applicable requirements of the CAA.

VIII. Environmental Justice Considerations

    The EPA defines environmental justice (EJ) as ``the fair treatment
and meaningful involvement of all people regardless of race, color,
national origin, or income with respect to the development,
implementation, and enforcement of environmental laws, regulations, and
policies.'' \155\ The EPA further defines the term ``fair treatment''
to mean that ``no group of people should bear a disproportionate burden
of environmental harms and risks, including those resulting from the
negative environmental consequences of industrial, governmental, and
commercial operations or programs and policies.'' \156\ Recognizing the
importance of these considerations to local communities, the EPA
conducted an environmental justice screening analysis around the
location of the facilities associated with this action to identify
potential environmental stressors on these communities and the
potential impacts of this action. However, the EPA is providing the
information associated with this analysis for informational purposes
only. The information provided herein is not a basis of the proposed
action.
---------------------------------------------------------------------------

    \155\ See https://www.epa.gov/environmentaljustice/learn-about-environmental-justice.
    \156\ Id.
---------------------------------------------------------------------------

    The EPA conducted the screening analyses using EJScreen, an EJ
mapping and screening tool that provides the EPA with a nationally
consistent dataset and approach for combining various environmental and
demographic indicators.\157\ The EJScreen tool presents these
indicators at a Census block group (CBG) level or a larger user-
specified ``buffer'' area that covers multiple CBGs.\158\ An individual
CBG is a cluster of contiguous blocks within the same census tract and
generally contains between 600 and 3,000 people. EJScreen is not a tool
for performing in-depth risk analysis, but is instead a screening tool
that provides an initial representation of indicators related to EJ and
is subject to uncertainty in some underlying data (e.g., some
environmental indicators are based on monitoring data which are not
uniformly available; others are based on self-reported data).\159\ For
informational purposes, we have summarized EJScreen data within larger
``buffer'' areas covering multiple block groups and representing the
average resident within the buffer areas surrounding the eight
facilities for which we are proposing to rescind emission limits.
EJScreen environmental indicators help screen for locations where
residents may experience a higher overall pollution burden than would
be expected for a block group with the same total population in the
U.S. These indicators of overall pollution burden include estimates of
ambient particulate matter (PM2.5) and ozone concentration,
a score for traffic proximity and volume, percentage of pre-1960
housing units (lead paint indicator), and scores for proximity to
Superfund sites, risk management plan (RMP) sites, and hazardous waste
facilities.\160\ EJScreen also provides information on demographic
indicators, including percent low-income, communities of color,
linguistic isolation, and less than high school education.
---------------------------------------------------------------------------

    \157\ The EJSCREEN tool is available at https://www.epa.gov/ejscreen.
    \158\ See https://www.census.gov/programs-surveys/geography/about/glossary.html.
    \159\ In addition, EJSCREEN relies on the five-year block group
estimates from the U.S. Census American Community Survey. The
advantage of using five-year over single-year estimates is increased
statistical reliability of the data (i.e., lower sampling error),
particularly for small geographic areas and population groups. For
more information, see https://www.census.gov/content/dam/Census/library/publications/2020/acs/acs_general_handbook_2020.pdf.
    \160\ For additional information on environmental indicators and
proximity scores in EJSCREEN, see ``EJSCREEN Environmental Justice
Mapping and Screening Tool: EJSCREEN Technical Documentation,''
Chapter 3 and Appendix C (September 2019) at https://www.epa.gov/sites/default/files/2021-04/documents/ejscreen_technical_document.pdf.
---------------------------------------------------------------------------

    The EPA prepared EJScreen reports covering buffer areas of
approximately 6-mile radii around the 8 facilities

covered by the 2016 Final Rule. From those reports, two facilities,
Tolk and Monticello, showed EJ indices greater than the 80th national
percentiles.\161\ For Tolk, the EJ indices greater than the 80th
national percentiles were for ozone and lead paint, which are not
affected by this proposed action. For Monticello, the EJ indices
greater than the 80th national percentiles were for PM2.5,
air toxics cancer risk, air toxics respiratory hazard index, RMP
facility proximity, and wastewater discharge. However, the Monticello
facility permanently shut down in 2018.\162\ No currently operating
facility for which we are proposing to rescind emission limits showed
an EJ index greater than the 80th national percentile for
PM2.5, diesel particulate matter, air toxics cancer risk,
air toxics respiratory hazard index, traffic proximity, Superfund site
proximity, RMP facility proximity, hazardous waste site proximity,
underground storage tanks, or wastewater discharge. The full, detailed
EJScreen reports are provided in the docket for this rulemaking.
---------------------------------------------------------------------------

    \161\ For a place at the 80th percentile nationwide, that means
20 percent of the U.S. population has a higher value. EPA identified
the 80th percentile filter as an initial starting point for
interpreting EJScreen results. The use of an initial filter promotes
consistency for EPA programs and regions when interpreting screening
results.
    \162\ See letter dated February 8, 2018, from Kim Mireles of
Luminant to the TCEQ requesting to cancel certain air permits and
registrations for Monticello available in the docket for this
action.
---------------------------------------------------------------------------

    This action proposes to again disapprove portions of the Texas and
Oklahoma Regional Haze SIPs for the first planning period but proposes
to make the determination that no further federal action is necessary
to address the proposed SIP disapprovals. As a result, this action also
proposes to rescind SO2 emission limitations for 8
facilities in Texas. Exposure to SO2 is associated with
significant public health effects. Short-term exposures to
SO2 can harm the human respiratory system and make breathing
difficult. People with asthma, particularly children, are sensitive to
these effects of SO2.\163\ However, the 2016 Final Rule was
stayed by the Fifth Circuit on July 15, 2016, and the emission
limitations have not gone into effect and therefore have never been
implemented. Therefore, we expect that this action will not change
potential impacts to communities. There is nothing in the record that
indicates that this proposed action, if finalized, would have
disproportionately high or adverse human health or environmental
effects on communities with environmental justice concerns.
---------------------------------------------------------------------------

    \163\ See https://www.epa.gov/so2-pollution/sulfur-dioxide-basics#effects.
---------------------------------------------------------------------------

IX. Impact on Areas of Indian Country

    Following the U.S. Supreme Court decision in McGirt v. Oklahoma,
140 S. Ct. 2452 (2020), the Governor of the State of Oklahoma requested
approval under section 10211(a) of the Safe, Accountable, Flexible,
Efficient Transportation Equity Act of 2005: A Legacy for Users, Public
Law 109-59, 119 Stat. 1144, 1937 (August 10, 2005) (``SAFETEA''), to
administer in certain areas of Indian country (as defined at 18 U.S.C.
1151) the State's environmental regulatory programs that were
previously approved by the EPA for areas outside of Indian country. The
State's request excluded certain areas of Indian country further
described below. In addition, the State only sought approval to the
extent that such approval is necessary for the State to administer a
program in light of Oklahoma Dept. of Environmental Quality v. EPA, 740
F.3d 185 (D.C. Cir. 2014).\164\
---------------------------------------------------------------------------

    \164\ In ODEQ v. EPA, the D.C. Circuit held that under the CAA,
a state has the authority to implement a SIP in non-reservation
areas of Indian country in the state, where there has been no
demonstration of tribal jurisdiction. Under the D.C. Circuit's
decision, the CAA does not provide authority to states to implement
SIPs in Indian reservations. ODEQ did not, however, substantively
address the separate authority in Indian country provided
specifically to Oklahoma under SAFETEA. That separate authority was
not invoked until the State submitted its request under SAFETEA, and
was not approved until EPA's decision, described in this section, on
October 1, 2020.
---------------------------------------------------------------------------

    On October 1, 2020, the EPA approved Oklahoma's SAFETEA request to
administer all the State's EPA-approved environmental regulatory
programs, including the Oklahoma SIP, in the requested areas of Indian
country. As requested by Oklahoma, the EPA's approval under SAFETEA
does not include Indian country lands, including rights-of-way running
through the same, that: (1) qualify as Indian allotments, the Indian
titles to which have not been extinguished, under 18 U.S.C. 1151(c);
(2) are held in trust by the United States on behalf of an individual
Indian or Tribe; or (3) are owned in fee by a Tribe, if the Tribe (a)
acquired that fee title to such land, or an area that included such
land, in accordance with a treaty with the United States to which such
Tribe was a party, and (b) never allotted the land to a member or
citizen of the Tribe (collectively ``excluded Indian country lands'').
    EPA's approval under SAFETEA expressly provided that to the extent
EPA's prior approvals of Oklahoma's environmental programs excluded
Indian country, any such exclusions are superseded for the geographic
areas of Indian country covered by the EPA's approval of Oklahoma's
SAFETEA request.\165\ The approval also provided that future revisions
or amendments to Oklahoma's approved environmental regulatory programs
would extend to the covered areas of Indian country (without any
further need for additional requests under SAFETEA).\166\
---------------------------------------------------------------------------

    \165\ The EPA's prior actions relating to Oklahoma's SIP
frequently noted that the SIP was not approved to apply in areas of
Indian country (consistent with the D.C. Circuit's decision in ODEQ
v. EPA) located in the state. See, e.g., 76 FR 81728, 81756 (Dec.
28, 2011); 81 FR 296, 348 (Jan. 5, 2016). Such prior expressed
limitations are superseded by the EPA's approval of Oklahoma's
SAFETEA request.
    \166\ On December 22, 2021, EPA proposed to withdraw and
reconsider the October 1, 2020 SAFETEA approval. See https://www.epa.gov/ok/proposed-withdrawal-and-reconsideration-and-supporting-information. EPA expects to have further discussions with
tribal governments and State of Oklahoma as part of this
reconsideration. EPA also notes that the October 1, 2020 approval is
the subject of a pending challenge in federal court. Pawnee Nation
of Oklahoma v. Regan, No. 20-9635 (10th Cir.). EPA may make further
changes to the approval of Oklahoma's program to reflect the outcome
of the proposed withdrawal and reconsideration of the October 1,
2020 SAFETEA approval. To the extent any change occurs in the scope
of Oklahoma's SIP authority in Indian country before the
finalization of this proposed rule, such a change may affect the
scope of the EPA's final action on the proposed rule.
---------------------------------------------------------------------------

    As explained earlier in this action, the EPA is proposing to again
address regional haze obligations for the first planning period in
Texas and Oklahoma. More specifically, we are proposing again to
disapprove portions of the Oklahoma Regional Haze SIP and Texas
Regional Haze SIP submissions that relate to reasonable progress for
the first planning period from 2008-2018. Consistent with the D.C.
Circuit's decision in ODEQ v. EPA and with EPA's October 1, 2020,
SAFETEA approval, if this disapproval is finalized as proposed, this
disapproval will apply to all Indian country within Oklahoma, other
than the excluded Indian country lands, as described earlier. Because--
per the State's request under SAFETEA--EPA's October 1, 2020, SAFETEA
approval does not displace any SIP authority previously exercised by
the State under the CAA as interpreted in ODEQ v. EPA, the SIP
disapproval will also apply to any Indian allotments or dependent
Indian communities located outside of an Indian reservation over which
there has been no demonstration of tribal authority.

X. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Overview and
Executive Order 14094: Modernizing Regulatory Review

    This action is exempt from review by the Office of Management and
Budget (OMB) under Executive Order 12866, as amended by Executive Order
14094, because the proposed FIP, if finalized, would constitute a rule
of particular applicability, as it proposes to rescind source specific
requirements for electric generating units at eight different
facilities located only in Texas.

B. Paperwork Reduction Act

    This action does not impose any new information collection burden
under the PRA. Because the proposed rescission of source specific
emission limits applies to only eight different facilities, the
Paperwork Reduction Act does not apply. See 5 CFR 1320.3(c).

C. Regulatory Flexibility Act

    I certify that this action will not have a significant impact on a
substantial number of small entities under the RFA. This action will
not impose any requirements on small entities. The proposed action, if
finalized, will rescind source specific requirements for electric
generating units s at eight different facilities, none of which are
small entities as defined by the RFA.

D. Unfunded Mandates Reform Act

    The EPA has determined that Title II of UMRA does not apply to this
proposed rule. In 2 U.S.C. 1502(1) all terms in Title II of UMRA have
the meanings set forth in 2 U.S.C. 658, which further provides that the
terms ``regulation'' and ``rule'' have the meanings set forth in 5
U.S.C. 601(2). Under 5 U.S.C. 601(2), ``the term `rule' does not
include a rule of particular applicability relating to . . .
facilities.'' Because this proposed rule is a rule of particular
applicability relating to specific EGUs located at eight named
facilities, the EPA has determined that it is not a ``rule'' for the
purposes of Title II of UMRA.

E. Executive Order 13132: Federalism

    This proposed action does not have federalism implications. It will
not have substantial direct effects on the states, on the relationship
between the national government and the states, or on the distribution
of power and responsibilities among the various levels of government.

F. Executive Order 13175: Consultation and Coordination With Indian
Tribal Governments

    This proposed disapproval of a portion of the Oklahoma Regional
Haze SIP submission that relates to reasonable progress for the first
planning period (2008-2018) will apply, if finalized as proposed, to
certain areas in Oklahoma with a nexus to Indian country as discussed
in the preamble, and therefore has tribal implications as specified in
E.O. 13175 (65 FR 67249, November 9, 2000). However, this action will
neither impose substantial direct compliance costs on federally
recognized tribal governments, nor preempt tribal law. This action will
not impose substantial direct compliance costs on federally recognized
tribal governments because no actions will be required of tribal
governments. This action will also not preempt tribal law as no
Oklahoma tribe implements a regulatory program under the CAA, and thus
does not have applicable or related tribal laws. The EPA will offer
consultation with tribal officials to allow them to provide meaningful
input on this action.

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

    EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that EPA has reason to believe may disproportionately affect children,
per the definition of ``covered regulatory action'' in section 2-202 of
the Executive Order. Therefore, this action is not subject to Executive
Order 13045 because it does not concern an environmental health risk or
safety risk. Since this action does not concern human health, EPA's
Policy on Children's Health also does not apply.

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

    This proposed action is not subject to Executive Order 13211 (66 FR
28355 (May 22, 2001)), because it is not a significant regulatory
action under Executive Order 12866.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

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

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs
federal agencies, to the greatest extent practicable and permitted by
law, to make environmental justice part of their mission by identifying
and addressing, as appropriate, disproportionately high and adverse
human health or environmental effects of their programs, policies, and
activities on communities with environmental justice concerns.
    The EPA believes that the human health or environmental conditions
that exist prior to this action have the potential to result in
disproportionate and adverse human health or environmental effects on
communities with environmental concerns. As explained further in
section VIII, the EPA's screening analysis provides an assessment of
indicators related to environmental justice and overall pollution
burden around the location of the facilities associated with this
action and demonstrates the potential for disproportionate and adverse
effects on the areas located near at least two of the facilities
subject to this action; however, one of these facilities permanently
shut down in 2018. The other facility demonstrated EJ indices greater
than the 80th national percentiles for ozone and lead paint, which are
potential health and environmental stressors not affected by this
proposed action.
    The EPA believes that this action, if finalized, is not likely to
change the human health or environmental conditions that exist prior to
this action and that have the potential to result in disproportionate
and adverse human health or environmental effects on communities with
environmental concerns. This action is not expected to change potential
community impacts associated with these indexes or add disproportional
human health or environmental burden to these communities with the
recission of SO2 emission limits that have never gone into
effect. The analyses and proposed requirements included in this
proposed rulemaking are consistent with and commensurate with the
Regional Haze Rule and how that rule functions. Additionally, the EPA
conducted these analyses for informational purposes only, and in a
manner consistent with both the CAA and E.O. 12898.
    The EPA intends to promote fair treatment and provide meaningful
involvement in developing the final action through the public notice
and comment process. This will include a

virtual public hearing and public comment period, as well as additional
outreach to promote public engagement. Information related to this
action will be available on the EPA's website as well as in the docket
for this action.
    The information supporting this Executive Order review is contained
in section VIII of this Preamble as well as throughout the Preamble,
and all supporting documents have been placed in the public docket for
this action.

K. Determinations Under CAA Section 307(d)

    This proposed action is subject to the provisions of section
307(d). CAA section 307(d)(1)(B) provides that section 307(d) applies
to, among other things, ``the promulgation or revision of an
implementation plan by the Administrator under [CAA section 110(c)].''
42 U.S.C. 7407(d)(1)(B). If finalized, this proposed action would,
among other things, revise a federal implementation plan pursuant to
the authority of section 110(c). To the extent any portion of this
proposed action is not expressly identified under section 307(d)(1)(B),
the Administrator determines that the provisions of section 307(d)
apply to this proposed action. See CAA section 307(d)(1)(V) (the
provisions of section 307(d) apply to ``such other actions as the
Administrator may determine'').

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Regional haze, Reporting and
recordkeeping requirements, Sulfur dioxides, Visibility.

Michael S. Regan,
Administrator.

    For the reasons stated in the preamble, the EPA proposes to amend
40 CFR part 52 as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart LL--Oklahoma

0
2. Section 52.1928 is amended by revising paragraph (a)(5) to read as
follows:

Sec.  52.1928  Visibility protection.

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

Subpart SS--Texas

0
3. Section 52.2270 is amended by revising in paragraph (e) the ``Texas
Regional Haze SIP'' entry under the table titled ``EPA Approved
Nonregulatory Provisions and Quasi-Regulatory Measures in the Texas
SIP'' to read as follows:

Sec.  52.2270   Identification of plan.

* * * * *
    (e) * * *

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

                                                  * * * * * * *
Texas Regional Haze SIP........  Statewide.........       3/19/2009  1/5/2016, 81 FR     The following sections
                                                                      350.                are not approved as
                                                                                part of the SIP: The
                                                                                reasonable progress
                                                                                goals, the reasonable
                                                                                progress four-factor
                                                                                analysis; and the
                                                                                calculation of the
                                                                                emission reductions
                                                                                needed to achieve the
                                                                                uniform rates of
                                                                                progress for the
                                                                                Guadalupe Mountains
                                                                                and Big Bend; the
                                                                                demonstration that the
                                                                                rate of progress for
                                                                                the implementation
                                                                                plan to attain natural
                                                                                conditions by 2064 is
                                                                                not reasonable and
                                                                                that the progress goal
                                                                                adopted by the State
                                                                                is reasonable;
                                                                                calculation of natural
                                                                                visibility conditions;
                                                                                calculation of the
                                                                                number of deciviews by
                                                                                which baseline
                                                                                conditions exceed
                                                                                natural visibility
                                                                                conditions; long-term
                                                                                strategy consultations
                                                                                with Oklahoma; Texas
                                                                                securing its share of
                                                                                reductions necessary
                                                                                to achieve the
                                                                                reasonable progress
                                                                                goals at Big Bend, the
                                                                                Guadalupe Mountains,
                                                                                and the Wichita
                                                                                Mountains; technical
                                                                                basis for its long-
                                                                                term strategy and
                                                                                emission limitations
                                                                                and schedules for
                                                                                compliance to achieve
                                                                                the RPGs for Big Bend,
                                                                                the Guadalupe
                                                                                Mountains and Wichita
                                                                                Mountains.

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------

Sec.  52.2302   [Removed and Reserved]

0
4. Remove and reserve Sec.  52.2302.
0
5. Section 52.2304 is amended by revising paragraph (e) to read as
follows:

Sec.  52.2304   Visibility protection.

* * * * *
    (e) The following portions of the Texas Regional Haze SIP submitted
March 19, 2009 are disapproved: The reasonable progress goals, the
reasonable progress four-factor analysis; and the calculation of the
emission reductions needed to achieve the uniform rates of progress for
the Guadalupe Mountains and Big Bend; the demonstration that the rate
of progress

for the implementation plan to attain natural conditions by 2064 is not
reasonable and that the progress goal adopted by the State is
reasonable; calculation of natural visibility conditions; calculation
of the number of deciviews by which baseline conditions exceed natural
visibility conditions; long-term strategy consultations with Oklahoma;
Texas securing its share of reductions necessary to achieve the
reasonable progress goals at Big Bend, the Guadalupe Mountains, and the
Wichita Mountains; technical basis for its long-term strategy and
emission limitations and schedules for compliance to achieve the
reasonable progress goals for Big Bend, the Guadalupe Mountains and
Wichita Mountains.
* * * * *
[FR Doc. 2023-15338 Filed 7-25-23; 8:45 am]
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