[Federal Register Volume 84, Number 188 (Friday, September 27, 2019)]
[Rules and Regulations]
[Pages 51033-51054]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-19497]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2015-0189; FRL-9998-66-Region 6]


Approval and Promulgation of Implementation Plans; Arkansas; 
Approval of Regional Haze State Implementation Plan Revision for 
Electric Generating Units in Arkansas

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: Pursuant to the Federal Clean Air Act (CAA or the Act), the 
Environmental Protection Agency (EPA) is finalizing an approval of a 
portion of a revision to the Arkansas State Implementation Plan (SIP) 
submitted by the State of Arkansas through the Arkansas Department of 
Environmental Quality (ADEQ) that addresses certain requirements of the 
CAA and the EPA's regional haze rules for the protection of visibility 
in mandatory Class I Federal areas (Class I areas) for the first 
implementation period. The EPA is taking final action to approve, among 
other things, the state's sulfur dioxide (SO2) and 
particulate matter (PM) best available retrofit technology (BART) 
determinations for electric generating units (EGUs) in Arkansas and the 
determination that no additional SO2 and PM controls at any 
Arkansas sources are necessary under reasonable progress. In 
conjunction with this final approval of a portion of the SIP revision, 
we are finalizing in a separate rulemaking, published elsewhere in this 
issue of the Federal Register, our withdrawal of the corresponding 
Federal implementation plan (FIP) provisions established in a prior 
action to address regional haze requirements for Arkansas.

DATES: This rule is effective on October 28, 2019.

ADDRESSES: The EPA has established a docket for this action under 
Docket No. EPA-R06-OAR-2015-0189. All documents in the dockets are 
listed on the http://www.regulations.gov website. Although listed in 
the index, some information is not publicly available, e.g., 
Confidential Business Information or other information whose disclosure 
is restricted by statute. Certain other material, such as copyrighted 
material, is not placed on the internet and will be publicly available 
only in hard copy form. Publicly available docket materials are 
available either electronically through http://www.regulations.gov or 
in hard copy at the EPA Region 6, 1201 Elm Street, Suite 500, Dallas, 
Texas 75270-2102.

FOR FURTHER INFORMATION CONTACT: Dayana Medina, 214-665-7241, 
medina.dayana@epa.gov, EPA Region 6, 1201 Elm Street, Suite 500, 
Dallas, Texas 75270-2102.

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

Table of Contents

I. Background
    A. The Regional Haze Program
    B. Our Previous Actions
II. Summary of Final Action
III. Response to Comments
    A. White Bluff SO2 BART for White Bluff
    B. Reasonable Progress
    C. Clean Air Act Section 110(l)
    D. Modeling
    E. Legal
    F. General
III. Final Action
IV. Incorporation by Reference
V. Statutory and Executive Order Reviews

I. Background

A. The Regional Haze Program

    Regional haze is visibility impairment that is produced by a 
multitude of sources and activities that are located across a broad 
geographic area and emit fine particulates (PM2.5) (e.g., 
sulfates, nitrates, organic carbon (OC), elemental carbon (EC), and 
soil dust), and their precursors (e.g., SO2, nitrogen oxides 
(NOX), and in some cases, ammonia (NH3) and 
volatile organic compounds (VOCs)). Fine particle precursors react in 
the atmosphere to form PM2.5, which impairs visibility by 
scattering and absorbing light. Visibility impairment reduces the 
clarity, color, and visible distance that can be seen. PM2.5 
can also cause serious adverse health effects and mortality in humans; 
it also contributes to environmental effects such as acid deposition 
and eutrophication.
    Data from the existing visibility monitoring network, the 
``Interagency Monitoring of Protected Visual Environments'' (IMPROVE), 
shows that visibility impairment caused by air pollution occurs 
virtually all of the time at most national parks and wilderness areas. 
In 1999, the average visual range \1\ in many Class I areas (i.e., 
national parks and memorial parks, wilderness areas, and international 
parks meeting certain size criteria) in the western United States was 
100-150 kilometers, or about one-half to two-thirds of the visual range 
that would exist under

[[Page 51034]]

estimated natural conditions.\2\ In most of the eastern Class I areas 
of the United States, the average visual range was less than 30 
kilometers, or about one-fifth of the visual range that would exist 
under estimated natural conditions. CAA programs have reduced emissions 
of some haze-causing pollution, lessening some visibility impairment 
and resulting in partially improved average visual ranges.\3\
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    \1\ Visual range is the greatest distance, in kilometers or 
miles, at which a dark object can be viewed against the sky.
    \2\ 64 FR 35715 (July 1, 1999).
    \3\ An interactive ``story map'' depicting efforts and recent 
progress by EPA and states to improve visibility at national parks 
and wilderness areas may be visited at: http://arcg.is/29tAbS3.
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    In Section 169A of the 1977 Amendments to the CAA, Congress created 
a program for protecting visibility in the nation's national parks and 
wilderness areas. This section of the CAA establishes as a national 
goal the prevention of any future, and the remedying of any existing, 
man-made impairment of visibility in 156 national parks and wilderness 
areas designated as mandatory Class I Federal areas.\4\ Congress added 
section 169B to the CAA in 1990 to address regional haze issues, and 
the EPA promulgated regulations addressing regional haze in 1999. The 
Regional Haze Rule \5\ revised the existing visibility regulations to 
add provisions addressing regional haze impairment and established a 
comprehensive visibility protection program for Class I areas. The 
requirements for regional haze, found at 40 CFR 51.308 and 51.309, are 
included in our visibility protection regulations at 40 CFR 51.300-309. 
The requirement to submit a regional haze SIP applies to all 50 states, 
the District of Columbia, and the Virgin Islands. States were required 
to submit the first implementation plan addressing regional haze 
visibility impairment no later than December 17, 2007.\6\
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    \4\ Areas designated as mandatory Class I Federal areas consist 
of National Parks exceeding 6,000 acres, wilderness areas and 
national memorial parks exceeding 5,000 acres, and all international 
parks that were in existence on August 7, 1977. 42 U.S.C. 7472(a). 
In accordance with section 169A of the CAA, EPA, in consultation 
with the Department of Interior, promulgated a list of 156 areas 
where visibility is identified as an important value. 44 FR 69122 
(November 30, 1979). The extent of a mandatory Class I area includes 
subsequent changes in boundaries, such as park expansions. 42 U.S.C. 
7472(a). Although states and tribes may designate as Class I 
additional areas which they consider to have visibility as an 
important value, the requirements of the visibility program set 
forth in section 169A of the CAA apply only to ``mandatory Class I 
Federal areas.'' Each mandatory Class I Federal area is the 
responsibility of a ``Federal Land Manager.'' 42 U.S.C. 7602(i). 
When we use the term ``Class I area'' in this action, we mean a 
``mandatory Class I Federal area.''
    \5\ Here and elsewhere in this document, the term ``Regional 
Haze Rule,'' refers to the 1999 final rule (64 FR 35714), as amended 
in 2005 (70 FR 39156, July 6, 2005), 2006 (71 FR 60631, October 13, 
2006), 2012 (77 FR 33656, June 7, 2012), and January 10, 2017 (82 FR 
3078).
    \6\ See 40 CFR 51.308(b). EPA's regional haze regulations 
require subsequent updates to the regional haze SIPs. 40 CFR 
51.308(g)-(i).
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    Section 169A of the CAA directs states to evaluate the use of 
retrofit controls at certain larger, often under-controlled, older 
stationary sources in order to address visibility impacts from these 
sources. Specifically, section 169A(b)(2)(A) of the CAA requires states 
to revise their SIPs to contain such measures as may be necessary to 
make reasonable progress toward the natural visibility goal, including 
a requirement that certain categories of existing major stationary 
sources \7\ built between 1962 and 1977 procure, install and operate 
BART controls. Larger ``fossil-fuel fired steam electric plants'' are 
one of these source categories. Under the Regional Haze Rule, states 
are directed to conduct BART determinations for ``BART-eligible'' 
sources that may be anticipated to cause or contribute to any 
visibility impairment in a Class I area. The evaluation of BART for 
electric generating units (EGUs) that are located at fossil-fuel fired 
power plants having a generating capacity in excess of 750 megawatts 
must follow the ``Guidelines for BART Determinations Under the Regional 
Haze Rule'' at appendix Y to 40 CFR part 51 (hereinafter referred to as 
the ``BART Guidelines''). Rather than requiring source-specific BART 
controls, states also have the flexibility to adopt an emissions 
trading program or other alternative program as long as the alternative 
provides for greater progress towards improving visibility than BART.
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    \7\ See 42 U.S.C. 7491(g)(7) (listing the set of ``major 
stationary sources'' potentially subject-to-BART).
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B. Our Previous Actions

    Arkansas submitted a SIP revision on September 9, 2008, to address 
the requirements of the first regional haze implementation period. On 
August 3, 2010, Arkansas submitted a SIP revision with mostly non-
substantive revisions to Arkansas Pollution Control and Ecology 
Commission (APCEC) Regulation 19, Chapter 15.\8\ On September 27, 2011, 
the State submitted supplemental information to address the regional 
haze requirements. We are hereafter referring to these regional haze 
submittals collectively as the ``2008 Arkansas Regional Haze SIP.'' On 
March 12, 2012, we partially approved and partially disapproved the 
2008 Arkansas Regional Haze SIP.\9\ On September 27, 2016, we 
promulgated a FIP (the Arkansas Regional Haze FIP) addressing the 
disapproved portions of the 2008 Arkansas Regional Haze SIP.\10\ Among 
other things, the FIP established SO2, NOX, and 
PM emission limits under the BART requirements for nine units at six 
facilities: Arkansas Electric Cooperative Corporation (AECC) Bailey 
Plant Unit 1; AECC McClellan Plant Unit 1; the American Electric Power/
Southwestern Electric Power Company (AEP/SWEPCO) Flint Creek Plant 
Boiler No. 1; Entergy Arkansas, Inc. (Entergy) Lake Catherine Plant 
Unit 4; Entergy White Bluff Plant Units 1 and 2; Entergy White Bluff 
Auxiliary Boiler; and the Domtar Ashdown Mill Power Boilers No. 1 and 
2. The FIP also established SO2 and NOX emission 
limits under the reasonable progress requirements for Entergy 
Independence Units 1 and 2.
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    \8\ The September 9, 2008 SIP submittal included APCEC 
Regulation 19, Chapter 15, which is the state regulation that 
identified the BART-eligible and subject-to-BART sources in Arkansas 
and established BART emission limits for subject-to-BART sources. 
The August 3, 2010 SIP revision did not revise Arkansas' list of 
BART-eligible and subject-to-BART sources or revise any of the BART 
requirements for affected sources. Instead, it included mostly non-
substantive revisions to the state regulation.
    \9\ 77 FR 14604.
    \10\ 81 FR 66332; see also 81 FR 68319 (October 4, 2016) 
(correction).
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    Following the issuance of the Arkansas Regional Haze FIP, the State 
of Arkansas and several industry parties filed petitions for 
reconsideration and an administrative stay of the final rule.\11\ On 
April 14, 2017, we announced our decision to reconsider several 
elements of the FIP, as follows: Appropriate compliance dates for the 
NOX emission limits for Flint Creek Boiler No. 1, White 
Bluff Units 1 and 2, and Independence Units 1 and 2; the low-load 
NOX emission limits applicable to White Bluff Units 1 and 2 
and Independence Units 1 and 2 during periods of operation at less than 
50 percent of the units' maximum heat input rating; the SO2 
emission limits for White Bluff Units 1 and 2; and the compliance dates 
for the SO2 emission limits for Independence Units 1 and 
2.\12\
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    \11\ See the docket associated with this rulemaking for a copy 
of the petitions for reconsideration and administrative stay 
submitted by the State of Arkansas; Entergy Arkansas Inc., Entergy 
Mississippi Inc., and Entergy Power LLC (collectively ``Entergy''); 
AECC; and the Energy and Environmental Alliance of Arkansas (EEAA).
    \12\ Letter from E. Scott Pruitt, Administrator, EPA, to 
Nicholas Jacob Bronni and Jamie Leigh Ewing, Arkansas Attorney 
General's Office (April 14, 2017). A copy of this letter is included 
in the docket, https://www.regulations.gov/document?D=EPA-R06-OAR-2015-0189-0240.
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    EPA also published a document in the Federal Register on April 25, 
2017, administratively staying the effectiveness of the NOX 
compliance dates in the FIP for the Flint Creek,

[[Page 51035]]

White Bluff, and Independence units, as well as the compliance dates 
for the SO2 emission limits for the White Bluff and 
Independence units for a period of 90 days.\13\ On July 13, 2017, the 
EPA published a proposed rule to extend the NOX compliance 
dates for Flint Creek Boiler No. 1, White Bluff Units 1 and 2, and 
Independence Units 1 and 2, by 21 months to January 27, 2020.\14\ 
However, EPA did not take final action on the July 13, 2017 proposed 
rule because on July 12, 2017, Arkansas submitted a proposed SIP 
revision with a request for parallel processing, addressing the 
NOX BART requirements for Bailey Unit 1, McClellan Unit 1, 
Flint Creek Boiler No. 1, Lake Catherine Unit 4, White Bluff Units 1 
and 2, and White Bluff Auxiliary Boiler, as well as the reasonable 
progress requirements with respect to NOX (Arkansas Regional 
Haze NOX SIP revision or Arkansas Phase I SIP revision). We 
proposed to approve the State's proposed SIP revision in parallel with 
the state's SIP process. Our proposed approval of the Arkansas Regional 
Haze NOX SIP revision and withdrawal of the corresponding 
parts of the Arkansas Regional Haze FIP was published in the Federal 
Register on September 11, 2017.\15\ On October 31, 2017, we received 
ADEQ's final Regional Haze NOX SIP revision addressing 
NOX BART for EGUs and the reasonable progress requirements 
with respect to NOX for the first implementation period. On 
February 12, 2018, we finalized our approval of the Arkansas Regional 
Haze NOX SIP revision and our withdrawal of the 
corresponding parts of the FIP.\16\
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    \13\ 82 FR 18994.
    \14\ 82 FR 32284.
    \15\ 82 FR 42627.
    \16\ 83 FR 5927 and 83 FR 5915 (February 12, 2018).
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    On August 8, 2018, Arkansas submitted a SIP revision (Arkansas 
Regional Haze SO2 and PM SIP revision or Arkansas Regional 
Haze Phase II SIP revision) addressing all remaining disapproved parts 
of the 2008 Regional Haze SIP, with the exception of the BART and 
associated long-term strategy requirements for the Domtar Ashdown Mill 
Power Boilers No. 1 and 2. The Phase II SIP revision also included a 
discussion on Arkansas' interstate visibility transport requirements. 
In a proposed rule published in the Federal Register on November 30, 
2018, we proposed approval of a portion of the SIP revision and we also 
proposed to withdraw the parts of the FIP corresponding to our proposed 
approvals.\17\ We stated in our proposed rule that we intend to propose 
action on the portion of the SIP revision discussing the interstate 
visibility transport requirements in a future proposed rulemaking. 
Since we proposed to withdraw certain portions of the FIP, we also 
proposed to redesignate the FIP by revising the numbering of certain 
paragraphs under 40 CFR 52.173 to reflect the removal of language 
applicable to EGUs and the retention of language applicable to the 
Domtar Ashdown Mill, the only remaining facility subject to the 
provisions of the FIP.
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    \17\ 83 FR 62204 (November 30, 2018).
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II. Summary of Final Action

    This action finalizes our proposed approval of a portion of the 
Arkansas Regional Haze SO2 and PM SIP revision. We are 
finalizing our approval of ADEQ's revised identification of the 6A 
Boiler at the Georgia-Pacific Crossett Mill as BART-eligible and the 
determination based on the additional information and technical 
analysis presented in the SIP revision that the Georgia-Pacific 
Crossett Mill 6A and 9A Boilers are not subject to BART. We are 
finalizing our approval of the state's BART determinations as follows: 
SO2 and PM BART for the AECC Bailey Plant Unit 1; 
SO2 and PM BART for the AECC McClellan Plant Unit 1; 
SO2 BART for the AEP/SWEPCO Flint Creek Plant Boiler No. 1; 
SO2 BART for Entergy White Bluff Units 1 and 2; 
SO2, NOX, and PM BART for the Entergy White Bluff 
Auxiliary Boiler; and the prohibition on burning of fuel oil at Entergy 
Lake Catherine Unit 4 until SO2 and PM BART determinations 
for the fuel oil firing scenario are approved into the SIP by EPA. 
These BART requirements have been made enforceable by the state through 
Administrative Orders and submitted as part of the SIP revision. We are 
finalizing our approval of these BART Administrative Orders as part of 
the SIP.
    We are finalizing our withdrawal of our prior approval of Arkansas' 
reliance on participation in the Cross-State Air Pollution Rule (CSAPR) 
for ozone season NOX to satisfy the NOX BART 
requirement for the White Bluff Auxiliary Boiler. The Arkansas Regional 
Haze NOX SIP revision erroneously stated that the Auxiliary 
Boiler participates in CSAPR for ozone season NOX and that 
the state was electing to rely on participation in that trading program 
to satisfy the Auxiliary Boiler's NOX BART requirements, and 
we erroneously approved this determination in a final action published 
in the Federal Register on February 12, 2018.\18\ We are finalizing our 
withdrawal of our approval of that determination for the Auxiliary 
Boiler and are replacing it with our final approval of a source-
specific NOX BART emission limit contained in the Arkansas 
Regional Haze SO2 and PM SIP Revision before us. The 
NOX BART requirement has been made enforceable by the state 
through an Administrative Order and submitted as part of the SIP 
revision. We are finalizing our approval of the Administrative Order 
that contains the NOX BART requirement as part of the SIP.
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    \18\ 83 FR 5927.
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    We are also finalizing our approval of Arkansas' reasonable 
progress determinations for Independence Units 1 and 2 and 
determination that no additional controls are necessary for 
SO2 or PM under the reasonable progress requirements for the 
first implementation period and are also agreeing with the state's 
calculation of revised RPGs for its Class I areas. We are finalizing 
our determination that, based on the state's currently approved SIP and 
the analyses and determinations we are approving in this final action, 
the state's reasonable progress obligations for the first 
implementation period have been satisfied. At this time, the majority 
of the BART requirements for the Domtar Ashdown Mill are satisfied by a 
FIP.\19\ The SIP revision explains that, based upon the BART 
determinations and analysis in that FIP, nothing further is currently 
needed for reasonable progress at the Domtar Ashdown Mill. EPA agrees 
with this determination. We do note that ADEQ recently submitted a SIP 
revision to address the BART requirements for Domtar Power Boilers No. 
1 and No. 2 that are currently satisfied by the FIP, and we intend to 
take action on that SIP revision addressing Domtar in a future 
rulemaking. At that time, we will evaluate any conclusions ADEQ draws 
in that SIP submittal about the adequacy of such SIP-based measures for 
reasonable progress. We will also evaluate any changes in the measures 
for the Domtar Ashdown Mill in that SIP revision relative to those 
currently in the FIP to determine whether the calculation of the 
reasonable progress goals for the first implementation period continues 
to be sufficient.
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    \19\ We note that the only exception to this is the PM 
determination for Domtar Ashdown Mill Power Boiler No. 1 contained 
in the 2008 Arkansas Regional Haze SIP. That BART determination was 
approved in our 2012 rulemaking. 77 FR 14604, March 12, 2012.
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    We are finalizing our approval of the components of the long-term 
strategy addressed by the Arkansas Regional

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Haze Phase II SIP revision and are finding that Arkansas' long-term 
strategy for reasonable progress with respect to all sources other than 
Domtar is approved. We are finalizing our approval of the 0.60 lb/MMBtu 
SO2 emission limitations for Independence Units 1 and 2, and 
these measures are now integrated into the State's long-term strategy. 
The long-term strategy is the compilation of all control measures a 
state relies on to make reasonable progress towards the goal of natural 
visibility conditions, including emission limitations corresponding to 
BART determinations. Because the Arkansas Regional Haze Phase II SIP 
revision does not address the BART requirements for Domtar, those 
components of the long-term strategy will remain satisfied by the FIP 
unless and until EPA has received and approved a SIP revision 
containing the required analyses and determinations for this 
facility.\20\
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    \20\ As noted above, ADEQ recently submitted a SIP revision to 
address the BART requirements for Domtar Power Boilers No. 1 and No. 
2 that are currently satisfied by the FIP. We intend to evaluate 
that SIP revision and to take action on it in a future rulemaking.
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    We are also finalizing our determination that Arkansas has 
satisfied the requirement under 40 CFR 51.308(i) to consult and 
coordinate with the federal land managers (FLMs).\21\ Additionally, we 
are finalizing our determination that Arkansas has satisfied the 
requirement under 40 CFR 51.308(d)(3)(i) to coordinate and consult with 
Missouri, which has Class I areas affected by Arkansas sources.\22\
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    \21\ 83 FR 62234.
    \22\ 83 FR 62234.
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    As we discussed in our proposal, the SIP revision also includes a 
discussion on interstate visibility transport. We are aware that 
Arkansas is working on a SIP revision to address the interstate 
visibility transport requirements for several national ambient air 
quality standards (NAAQS), and we therefore deferred evaluating and 
proposing action on the interstate visibility transport portion of the 
Arkansas Regional Haze Phase II SIP revision until a future proposed 
rulemaking.
    We are finalizing our approval of a portion of the Arkansas 
Regional Haze Phase II SIP revision as we have found it to meet the 
applicable provisions of the Act and EPA regulations and is consistent 
with EPA guidance. We received comments from several commenters on our 
proposed approval. Our responses to the substantive comments we 
received are summarized in Section III. We have fully considered all 
significant comments on our proposed action on the SIP revision 
submittal and have concluded that no changes to our final 
determinations are warranted.
    We are approving a portion of the Arkansas Regional Haze Phase II 
SIP revision submitted by ADEQ on August 8, 2018, as we have determined 
that it meets the regional haze SIP requirements, including the BART 
requirements in Sec.  51.308(e); the reasonable progress requirements 
in Sec.  51.308(d); and the long-term strategy requirements in Sec.  
51.308(d)(3). In conjunction with this final approval, we are 
finalizing in a separate rulemaking, published elsewhere in this issue 
of the Federal Register, our withdrawal of FIP provisions corresponding 
to the portions of the SIP revision we are taking final action to 
approve in this rulemaking.

III. Response to Comments

    The public comments received on our proposed rule are included in 
the publicly posted docket associated with this action at 
www.regulations.gov.\23\ We reviewed all public comments that we 
received on the proposed action. Below, we provide a summary of 
substantive comments and our responses. Summaries of all comments and 
our full responses thereto are contained in a separate document titled 
the Arkansas Regional Haze Phase II SIP Revision Response to Comments, 
which can be found in the docket associated with this final rulemaking.
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    \23\ Docket No. EPA-R06-OAR-2015-0189.
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A. White Bluff SO2 BART Requirements

    Comment: EPA proposed to approve ADEQ's determination that low 
sulfur coal with an emission rate of 0.60 lb/MMBtu on a 30-day rolling 
average is SO2 BART for White Bluff Units 1 and 2. However, 
the cost-effectiveness figures for dry scrubbers at White Bluff Units 1 
and 2 are well within the range of what has been found to be cost 
effective in other regional haze actions. EPA should reverse its 
position, disapprove ADEQ's White Bluff SO2 BART 
determination, and finalize its previous rule that SO2 
emission limits corresponding to dry scrubbers constitute 
SO2 BART at White Bluff.
    Response: We remind the commenter that each BART determination is 
dependent on the specific situation of the source and involves the 
consideration of a number of factors that usually vary on a case by 
case basis. This includes consideration of the five statutory factors 
required under the Regional Haze Rule at Sec.  51.308(e)(1)(ii)(A) and 
CAA section 169A(g)(2). BART determinations are source specific--what 
is a reasonable determination for one source may not be appropriate 
given the facts and circumstances applicable to another source. The 
states also have wide discretion in the evaluation of the five 
statutory factors and in formulating SIPs, so long as they satisfy the 
applicable requirements and provide a reasoned and rational basis for 
their decisions.
    While it is true that some SO2 BART controls required 
under other regional haze actions have similar cost-effectiveness 
figures as those for dry scrubbers for White Bluff, we find that ADEQ 
satisfied the requirements of the CAA and the Regional Haze Rule by 
fully considering the five statutory factors in the SO2 BART 
analysis for White Bluff Units 1 and 2. Taking into account the 
remaining useful life of White Bluff Units 1 and 2 (based on Entergy's 
enforceable Administrative Order to cease coal combustion by December 
31, 2028), and the resulting cost-effectiveness of controls, as well as 
the anticipated visibility improvement of the SO2 control 
options and the other BART factors, ADEQ determined that SO2 
BART for White Bluff Units 1 and 2 is an emission limit of 0.60 lb/
MMBtu based on the use of low sulfur coal beginning no later than three 
years from the effective date of the Administrative Order (August 7, 
2021) through the end of 2028.
    As we explained in our proposal, ADEQ's cost analysis was based on 
a dry scrubber system assuming an inlet coal sulfur content of 1.2 lb/
MMBtu, which is based on Entergy's current coal contract sulfur 
limit.\24\ However, the White Bluff units have historically burned coal 
with a lower sulfur content. Therefore, we relied on our FIP's cost 
analysis for dry scrubbers for White Bluff, which was based on a 
scrubber system designed to burn coal having a sulfur content 
consistent with what the units have historically burned, and we 
adjusted for a 7-year as opposed to a 30-year capital cost recovery 
period to reflect that the units will cease coal combustion by the end 
of 2028.\25\ Based on our revised cost estimates, dry scrubbers are 
estimated to cost approximately $4,376/ton for Unit 1 and $4,129/ton 
for Unit 2. The visibility benefit of dry scrubbers at White Bluff 
Units 1 and 2 is anticipated to be 0.603 dv at Caney Creek and 0.642 dv 
at Upper Buffalo for Unit 1 and 0.574 dv at Caney Creek and 0.632 dv at 
Upper Buffalo for Unit 2; Caney Creek and Upper Buffalo are the two 
Class I areas

[[Page 51037]]

where White Bluff Units 1 and 2 have the greatest modeled baseline 
visibility impacts.\26\
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    \24\ 83 FR 62222.
    \25\ 83 FR 62222.
    \26\ See 83 FR 62221-62222.
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    In this instance, we believe Arkansas is within its discretion to 
evaluate the BART factors as it has done, and we find that the state 
has presented a reasoned basis for its BART determination and has met 
all CAA and Regional Haze Rule requirements in making the BART 
determination for White Bluff. Considering all the above, we are 
finalizing our approval of ADEQ's determination that SO2 
BART for White Bluff Units 1 and 2 is an emission limit of 0.60 lb/
MMBtu based on the use of low sulfur coal, with an enforceable 
Administrative Order requiring Entergy to cease coal combustion at 
White Bluff Units 1 and 2 by December 31, 2028.
    Comment: EPA's proposed approval of ADEQ's determination that low 
sulfur coal with an emission rate of 0.60 lb/MMBtu on a 30-day rolling 
average is SO2 BART for White Bluff Units 1 and 2 and 
rejection of dry scrubbers is arbitrary when compared to the Flint 
Creek SO2 BART determination. The SO2 BART 
determination for Flint Creek Boiler No. 1 was based on very similar 
cost-effectiveness figures for dry scrubbers, but in that case, EPA 
required a scrubber as BART. EPA should reverse its position and 
disapprove ADEQ's SO2 BART determination for White Bluff 
Units 1 and 2.
    Response: We disagree with the commenter that our proposed approval 
of ADEQ's SO2 BART determination for White Bluff Units 1 and 
2 is arbitrary when compared to our proposed approval of the Flint 
Creek SO2 BART determination. In particular, the commenter 
contends that it is arbitrary and capricious for EPA to find that White 
Bluff SO2 BART is an emission limit based on low-sulfur 
coal, while also finding that SO2 BART for Flint Creek is an 
emission limits based on a dry scrubber. EPA did not make these 
findings in the context of a FIP, but rather proposed to approve ADEQ's 
determinations based on our finding that the State reasonably 
determined that SO2 BART for White Bluff Units 1 and 2 is an 
emission limit of 0.60 lb/MMBtu based on the use of low sulfur coal and 
that SO2 BART for Flint Creek Boiler No. 1 is an emission 
limit of 0.06 lb/MMBtu based on the use of a dry scrubber. The states 
have wide discretion in the evaluation of the five statutory factors 
and in formulating SIPs, so long as they satisfy the applicable 
requirements and provide a reasoned and rational basis for their 
decisions. Furthermore, BART determinations are source specific--what 
is a reasonable determination for one source may not be appropriate 
given the facts and circumstances applicable to another source. In this 
instance, we believe Arkansas is within its discretion to evaluate the 
BART factors as it has done, and we find that the state has presented a 
reasoned basis for its BART determinations and has met all CAA and 
Regional Haze Rule requirements in making the SO2 BART 
determinations for White Bluff and Flint Creek.
    We note that the cost-effectiveness figures for dry scrubbers for 
White Bluff are in fact higher than that for a Novel Integrated 
Deacidification (NID) system, a type of dry scrubbing technology, for 
Flint Creek. In our proposed rule, we estimated the cost effectiveness 
of dry scrubbers for White Bluff Units 1 and 2 to be $4,376/ton for 
Unit 1 and $4,129/ton for Unit 2. The visibility benefit of dry 
scrubbers at White Bluff is anticipated to be 0.603 dv at Caney Creek 
and 0.642 dv at Upper Buffalo for Unit 1 and 0.574 dv at Caney Creek 
and 0.632 dv at Upper Buffalo for Unit 2; Caney Creek and Upper Buffalo 
are the two Class I areas where White Bluff Units 1 and 2 have the 
greatest modeled baseline visibility impacts.\27\ The cost-
effectiveness of a NID system for Flint Creek is $3,845/ton. We 
consider the cost of a dry scrubber at Flint Creek to be generally cost 
effective when also taking into account the level of visibility benefit 
of the control and the other BART factors. The visibility benefit of a 
NID system at Flint Creek Boiler No. 1 is anticipated to be 0.615 dv at 
Caney Creek and 0.464 dv at Upper Buffalo, the two Class I areas where 
Flint Creek Boiler No. 1 has the greatest modeled baseline visibility 
impacts.\28\ The anticipated level of visibility benefit at Caney Creek 
and Upper Buffalo due to dry scrubbers at White Bluff Units 1 and 2 is 
comparable to the anticipated visibility benefit due to NID at Flint 
Creek Boiler No. 1, but the cost-effectiveness figures for dry 
scrubbers at White Bluff are higher than that for Flint Creek, and 
start to go into the higher end of what has been found to be cost 
effective in other regional haze actions when also taking into account 
the level of visibility benefit of the controls and other factors.\29\ 
Additionally, the NID system was already installed and operating at 
Flint Creek Boiler No. 1 at the time that ADEQ finalized and submitted 
the Reginal Haze SO2 and PM SIP revision. Thus, we believe 
it would have been unreasonable for ADEQ to find that SO2 
BART for Flint Creek Boiler No. 1 is not a NID system when those 
controls are already installed and operational at the facility. In 
contrast, there is no planned installation of this control equipment at 
White Bluff Units 1 and 2, which have a shortened remaining useful life 
based on an enforceable Administrative Order that is part of this SIP 
revision. Furthermore, since Flint Creek Boiler No. 1 is currently 
assumed to continue operating for at least another 30 years while White 
Bluff Units 1 and 2 are required to cease coal combustion by the end of 
December 2028 based on the enforceable Administrative Order that is 
part of this SIP revision, we find that it is reasonable for ADEQ to 
have determined that SO2 BART for Flint Creek Boiler No. 1 
is an emission limit based on the use of dry scrubbers while 
SO2 BART for White Bluff Units 1 and 2 is an emission limit 
based on the use of low sulfur coal. We are taking final action to 
approve the state's SO2 BART determinations for these units.
---------------------------------------------------------------------------

    \27\ See 83 FR 62221-62222.
    \28\ See 83 FR 62218.
    \29\ 83 FR 62222.
---------------------------------------------------------------------------

    Comment: Although EPA's estimated dry scrubber costs demonstrate 
that this control technology is not cost-effective for White Bluff 
Units 1 and 2, the costs of dry scrubbers are actually underestimated 
by EPA. EPA's cost assessment assumes that White Bluff will combust 
coal with a sulfur content of 0.68 lb/MMBtu, which was the maximum 
monthly emission rate from 2009-2013, and its calculation of the 
equipment costs reflects scrubbers sized to accommodate this sulfur 
content. However, EPA is incorrect to assume that the sulfur content of 
coal that will be combusted at the plant in the future will not exceed 
the maximum monthly average sulfur content from 2009-2013. EPA ignores 
the fact that the plant can receive coal with a sulfur content up to 
1.2 lb/MMBtu pursuant to its coal contracts, and that White Bluff in 
fact had a maximum 3-hour average emission rate of 1.1 lb/MMBtu from 
2014-2016. A dry scrubber must be designed to handle the highest sulfur 
content that may be combusted at the unit, as an inappropriately 
designed scrubber would be incapable of addressing SO2 
emissions exceeding the design limit. If the scrubber system at White 
Bluff were designed to treat flue gas with a SO2 emission 
rate of 0.68 lb/MMBtu, the system would be inadequately sized to add 
sufficient reagent when sulfur levels increase beyond that level, which 
would result in emissions above the proposed emission rate for that 
period of operation. The cost analysis in the SIP

[[Page 51038]]

revision appropriately reflected the installation of scrubbers designed 
to handle the maximum coal sulfur content at the plant. If EPA retains 
its cost estimate based on the installation of scrubbers that can 
accommodate only lower sulfur coal, then EPA must account for the fact 
that Entergy would need to ensure that only lower sulfur coal is 
purchased in the future. The resulting increase in fuel costs must be 
accounted for in the scrubber cost analysis. Failure to do so renders 
EPA's estimates inaccurate and does not allow for a proper evaluation 
of the costs of dry scrubbers at White Bluff.
    Response: We disagree with the commenter's approach for estimating 
the cost-effectiveness of dry scrubbers for White Bluff Units 1 and 2. 
The commenter argues that a mismatch between the cost of the scrubber 
systems and the SO2 emission baseline against which the 
cost-effectiveness will be measured can be legitimately introduced. 
Specifically, the commenter argues that the units could in the future 
burn coal containing a higher sulfur content than what has been burned 
in the past, emphasizing that the plant can receive coal with a sulfur 
content up to 1.2 lb/MMBtu pursuant to its coal contracts. Therefore, 
the commenter insists on costing the dry scrubbers for White Bluff 
Units 1 and 2 assuming the units will burn coal with a sulfur content 
of 1.2 lb/MMBtu, while at the same time basing the calculation of the 
SO2 tons reduced in the cost-effectiveness calculations on a 
lower emissions level of 0.68 lb/MMBtu based on the same 2009-2013 
SO2 baseline period that the commenter objects to for 
purposes of costing the scrubbers.\30\ This cherry-picking of emission 
rates has ramifications for the scrubber cost effectiveness 
calculation, in which the annualized cost of the controls are compared 
to the SO2 tons reduced from the SO2 baseline. A 
scrubber capable of treating a higher sulfur coal is more expensive. 
While Entergy is free to design a scrubber capable of burning a coal 
with a higher sulfur content (assuming all regulatory requirements are 
otherwise met), this expense must be balanced against the greater 
SO2 removal capabilities of such a scrubber. Otherwise, the 
cost effectiveness calculation is unreasonably skewed. In other words, 
if the Entergy cost analysis on which the SIP revision relies had also 
based the calculation of the SO2 tons reduced on an assumed 
baseline emission rate of 1.2 lb/MMBtu, this would have reflected 
greater tons of SO2 removed, which would in turn result in 
cost estimates more cost-effective than reflected in Entergy's 
estimates.
---------------------------------------------------------------------------

    \30\ See the Arkansas Regional Haze SO2 and PM SIP 
Revision, p. 4-4.
---------------------------------------------------------------------------

    Instead of relying on the SIP's cost estimates, which are based on 
Entergy's estimates for a dry scrubber designed to treat coal with a 
sulfur content of 1.2 lb/MMBtu, we presented revised cost estimates for 
dry scrubbers for White Bluff in our proposal. After considering our 
lower revised cost numbers, we still agree with ADEQ's SO2 
BART determination for White Bluff Units 1 and 2 in the SIP revision. 
Our revised cost estimates rely on our FIP's cost analysis, which was 
based on a scrubber system designed to burn coal having a sulfur 
content of 0.68 lb/MMBtu, which is the units' maximum monthly emission 
rate from 2009-2013.\31\ Assuming a coal sulfur content that reflects 
the sulfur levels of the coal historically burned at the units is the 
appropriate basis for our cost estimate, consistent with the BART 
Guidelines: \32\
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    \31\ 83 FR 62222.
    \32\ 70 FR 39167.

    The baseline emissions rate should represent a realistic 
depiction of anticipated annual emissions for the source. In 
general, for the existing sources subject to BART, you will estimate 
the anticipated annual emissions based upon actual emissions from a 
baseline period. When you project that future operating parameters 
(e.g., limited hours of operation or capacity utilization, type of 
fuel, raw materials or product mix or type) will differ from past 
practice, and if this projection has a deciding effect in the BART 
determination, then you must make these parameters or assumptions 
into enforceable limitations. In the absence of enforceable 
limitations, you calculate baseline emissions based upon 
---------------------------------------------------------------------------
continuation of past practice.

    Based on the BART Guidelines, the presumption is that the baseline 
emissions should be based on historical emissions. If future operations 
are expected to differ from past practices, and this impacts the BART 
analysis, an enforceable mechanism must be in place. The example in the 
above reference to the BART Guidelines anticipates that future 
operations will cause the baseline to be lower, resulting in a 
correspondingly lower denominator in the $/ton cost effectiveness 
calculation, thus resulting in the cost effectiveness seeming less 
attractive (higher) and triggering the need for an enforceable 
mechanism to ensure the integrity of the cost-effectiveness calculation 
into the future. The same principle applies to Entergy's situation, in 
that using a higher scrubber cost for scrubbing a higher sulfur coal, 
in conjunction with using an unrepresentative (lower) baseline, both 
act to make the $/ton cost effectiveness of the scrubber seem less 
attractive (higher). In this instance, we would not require an 
enforceable mechanism to ensure Entergy burns a higher sulfur coal, but 
the need to ensure the future integrity of the cost-effectiveness 
calculation nevertheless remains.
    There are two obvious ways to ensure the cost effectiveness 
calculation accurately reflects the costs and emission reductions of 
scrubbers for White Bluff: Either (1) the higher cost of a scrubber 
designed to handle a higher sulfur coal must be balanced against its 
greater SO2 reduction potential, or (2) the scrubber 
system's capability and cost must match the facility's historical 
emissions. We took the latter approach in estimating the cost of dry 
scrubbers in our proposal. However, the commenter disagrees with either 
approach, arguing instead that the higher scrubber cost for scrubbing a 
higher sulfur coal (which it claims could be representative of future 
emission rates) should be paired with a historical (lower) baseline.
    We also note that the commenter does not appear to argue that 
basing the cost analysis on a scrubber system designed to burn coal 
having a sulfur content of 0.68 lb/MMBtu is inconsistent with its 
historical maximum monthly emission rate, but only suggests that in the 
future the White Bluff units may be burning coal containing a higher 
sulfur content. The commenter also points to the units' maximum 3-hour 
average emission rate of 1.1 lb/MMBtu from 2014-2016 in arguing that 
the cost analysis must reflect a dry scrubber that is designed to 
handle the highest sulfur content that may be combusted at the unit. 
However, we note that this is a maximum 3-hour average, while our cost 
estimates were based on a scrubber system designed to burn coal having 
a sulfur content of 0.68 lb/MMBtu, which is the units' maximum monthly 
emission rate from 2009-2013. This is significant because variations in 
emissions due to changes in coal quality, reagent quality, or scrubber 
performance are normally accommodated in permitting by specifying a 
sufficiently long averaging time, such as a 30-day averaging period, 
which is specifically designed to average out short term fluctuations. 
In general, averaging smooths out fluctuations in data.\33\ 
Furthermore, the emission limit evaluated by ADEQ and Entergy in the 
BART analysis for scrubbers, if selected as BART, would have been on a 
rolling 30 boiler-

[[Page 51039]]

operating-day averaging period; therefore, the cost analysis should 
reflect the design of a scrubber that would meet the same averaging 
period. In this context, the maximum 3-hour emission rate does not hold 
much significance. Therefore, we do not agree with the commenter's 
argument that since White Bluff had a maximum 3-hour average emission 
rate of 1.1 lb/MMBtu, it is necessary to install a scrubber designed to 
treat flue gas with a SO2 emission rate of 1.2 lb/MMBtu.
---------------------------------------------------------------------------

    \33\ Thad Godish, Air Quality, Lewis Publishers, 2nd Ed., 1991, 
p. 216, Figure 7.1; Richard W. Boubel, Donald L. Fox, Bruce Turner, 
and Arthur C. Stern, Fundamentals of Air Pollution, Academic Press, 
3rd Ed., 1994, pp. 41--43.
---------------------------------------------------------------------------

    Considering the above, we disagree with the commenter that we 
underestimated the cost of dry scrubbers for White Bluff by basing our 
cost assessment on the assumption that White Bluff will combust coal 
with a sulfur content of 0.68 lb/MMBtu. Nevertheless, our disagreement 
with the commenter on the above issues does not ultimately impact our 
final action given that even after considering our lower cost 
estimates, we find that ADEQ reasonably exercised its discretion in 
concluding that the costs of dry scrubbers are not warranted after also 
taking into account the level of anticipated visibility benefit at the 
affected Class I areas due to these controls and the other BART 
factors, including consideration that an Administrative Order that is 
part of the SIP revision requires the White Bluff units to cease coal 
combustion by December 31, 2028. We are finalizing our proposed 
approval of ADEQ's determination that SO2 BART for White 
Bluff Units 1 and 2 is an emission limit of 0.60 lb/MMBtu based on the 
use of low sulfur coal.
    Comment: The commenter supports EPA's proposed approval of rolling 
30-day average BART SO2 emission limits of 0.60 lb/MMBtu for 
White Bluff Units 1 and 2 based on combustion of low sulfur coal. While 
EPA underestimates the costs of dry scrubbers at White Bluff, even its 
undervalued costs support a determination that add-on SO2 
control technology is not BART for White Bluff. EPA's cost estimates 
fail to include certain cost items that EPA claims are disallowed 
pursuant to the Control Cost Manual. These ``disallowed'' costs should 
be included in the cost analyses, as they reflect the actual costs of 
planning, installing, and operating controls. Accounting for the 
disallowed costs makes the control technologies even less cost-
effective. However, even EPA's flawed cost estimates demonstrate that 
dry sorbent injection (DSI), enhanced DSI and dry scrubbers are not 
cost-effective for White Bluff.
    Response: We appreciate the commenter's support of our proposed 
approval of ADEQ's determination that SO2 BART for White 
Bluff Units 1 and 2 are emission limits of 0.60 lb/MMBtu based on 
combustion of low sulfur coal. However, we disagree with the commenter 
that we have underestimated the costs of dry scrubbers at White Bluff. 
In particular, the commenter states that EPA's cost estimates fail to 
include certain cost items that EPA claims are disallowed pursuant to 
the Control Cost Manual and that Entergy continues to believe that 
these ``disallowed'' costs should be included in the cost analyses. The 
commenter claims these disallowed costs reflect the actual costs of 
planning, installing, and operating controls. We disagree with the 
commenter that the disallowed line items should be included in the cost 
analyses. As we discussed in our proposal, ADEQ's evaluation of 
controls in the SIP revision is based on Entergy's set of cost numbers 
that excludes the line items disallowed under the EPA Control Cost 
Manual,\34\ which the BART Guidelines specify should be the basis of 
cost estimates, where possible.\35\ We stated in our proposal that we 
agree that Allowance for Funds Used During Construction (AFUDC) and 
certain other cost items are not allowed to be considered in estimating 
the cost-effectiveness of controls for regional haze purposes under the 
EPA Control Cost Manual.\36\ We explained in our proposal that we, 
therefore, agree with ADEQ's decision to base its evaluation of 
controls on Entergy's set of cost numbers that did not include the 
disallowed line items instead of relying on the set of cost numbers 
that did include the disallowed line items.\37\ However, as we 
discussed in a previous response, we ultimately presented revised cost 
estimates for dry scrubbers for White Bluff in our proposal instead of 
relying on ADEQ's cost estimates from the SIP revision because ADEQ's 
cost estimates were based on Entergy's estimates for a dry scrubber 
that was inappropriately designed to treat coal with a sulfur content 
of 1.2 lb/MMBtu.
---------------------------------------------------------------------------

    \34\ 83 FR 62220.
    \35\ 40 CFR part 51, appendix Y, IV.D.4.a.
    \36\ 83 FR 62222.
    \37\ 83 FR 62222.
---------------------------------------------------------------------------

    As we have noted in a number of other regional haze actions, 
certain line items such as AFUDC, owner's costs, and escalation during 
construction are not valid costs under our Control Cost Manual 
methodology. We incorporate our responses to similar comments we have 
received in those actions here.\38\ The exclusion of these disallowed 
line items in estimating the cost-effectiveness of controls for BART 
purposes is consistent with the ``overnight'' methodology outlined in 
our Control Cost Manual. We note that the Ninth and Tenth Circuits have 
upheld our use of the overnight cost methodology and our long-standing 
position in the regional haze program that certain line items such as 
AFUDC are not allowed under the Control Cost Manual approach of cost 
estimating.\39\
---------------------------------------------------------------------------

    \38\ See for instance, our ``Response to Technical Comments for 
Sections E through H of the Federal Register Notice for the Oklahoma 
Regional Haze and Visibility Transport Federal Implementation 
Plan,'' Docket No. EPA-R06-OAR-2010-0190, 12/13/2011. See pages 7-
10, 12-21, 33-34, 46-47, 63-64, 68, 70-71, 80, 85-86, and 88. This 
document can also be found in the docket for our final action on the 
Arkansas Regional Haze Phase II SIP Revision (Docket No. EPA-R06-
OAR-2015-0189).
    \39\ See Ariz. ex rel. Darwin v. EPA, 815 F.3d 519 (9th Cir. 
2016), page 39: ``This argument restates Petitioners' objections to 
EPA's reliance on the overnight costing methodology when it 
partially disapproved Arizona's SIP. See supra note 14. EPA's use of 
such a methodology in its own FIP's cost analysis is, without doubt, 
reasonable.'' See also Oklahoma v. EPA, 723 F.3d 1201 (July 19, 
2013), cert. denied (U.S. May 27, 2014) where EPA disapproved 
certain BART determinations that did not rely on the overnight cost 
methodology as well as relied on certain cost items such AFUDC which 
are not allowed per the EPA Control Cost Manual.
---------------------------------------------------------------------------

    Despite our disagreement with the commenter on the above issues, we 
note that our position on these issues does not ultimately impact our 
final action given that even after considering the set of cost-
effectiveness figures that exclude the disallowed line items, we find 
that ADEQ reasonably determined that the costs of DSI, enhanced DSI, 
and dry scrubbers are not warranted after also taking into account the 
level of anticipated visibility benefit at the affected Class I areas 
due to these controls and the other BART factors, including 
consideration that an Administrative Order that is part of the SIP 
revision requires the White Bluff units to cease coal combustion by 
December 31, 2028. We are therefore finalizing our proposed approval of 
ADEQ's determination that SO2 BART for White Bluff Units 1 
and 2 is an emission limit of 0.60 lb/MMBtu based on the use of low 
sulfur coal.
    Comment: ADEQ's SO2 BART determination for White Bluff 
Units 1 and 2 is based on a voluntary decision made by Entergy to cease 
coal combustion at the units by December 31, 2028. White Bluff Units 1 
and 2 are co-owned by Entergy, AECC, and several Arkansas 
municipalities. Entergy and AECC are public utilities subject to the 
jurisdiction of the Arkansas Public Service Commission (APSC). Since 
the Administrative Order requires Entergy to comply with applicable 
law, EPA should acknowledge that Entergy is required to

[[Page 51040]]

seek APSC approval for the cessation of coal combustion at White Bluff 
prior to the end of its effective useful life.
    Response: The relevant consideration for BART determinations is 
whether any commitment to change future operations, when such changes 
impact the outcome of the BART analysis, is enforceable for purposes of 
the SIP.\40\ Under a BART analysis, the remaining useful life of a 
scrubber is assumed to be 30 years unless a facility has an enforceable 
agreement in place to shut down or cease coal combustion earlier in 
order for EPA or the state to rely on it in calculating the remaining 
useful life as part of the BART determination analysis. Here, Entergy 
entered into an Administrative Order with ADEQ, which is an enforceable 
document that ADEQ has incorporated into its SIP revision, to cease 
coal combustion at Units 1 and 2 at White Bluff by December 31, 2028. 
It was therefore appropriate for ADEQ to rely on this cease to combust 
coal date for White Bluff Units 1 and 2 in the calculation of the 
units' remaining useful life, which is used to determine the cost 
effectiveness of controls in the BART analysis.
---------------------------------------------------------------------------

    \40\ See 40 CFR part 51, appendix Y, IV.D.4.d, k.
---------------------------------------------------------------------------

    To the extent the commenter is contending that the Administrative 
Order itself requires Entergy to obtain APSC approval in order to be 
able to make the changes in operations necessary to comply with the 
requirements of that Administrative Order (AO), we note that Provision 
No. 12 provides that ``Nothing contained in this AO shall relieve 
Entergy Arkansas of any obligations imposed by any other applicable 
local, state, or federal laws, nor, except as specifically provided 
herein, shall this AO be deemed in any way to relieve Entergy Arkansas 
of responsibilities contained in the permit.'' \41\ EPA cannot comment 
on what other local or state laws are applicable including whether 
Entergy and some of the White Bluff co-owners are public utilities 
subject to the jurisdiction of the APSC. With regard to the commenter's 
statement that Entergy will be required to obtain approval from the 
APSC with respect to the provisions in the Administrative Order, we 
note that such matter falls under the jurisdiction of Arkansas state 
law and is outside of the scope of our proposal.
---------------------------------------------------------------------------

    \41\ The Administrative Order for Entergy can be found in the 
Arkansas Regional Haze SO2 and PM BART SIP Revision. See 
Paragraph 12 of the Order and Agreement Section. https://www.adeq.state.ar.us/air/planning/sip/pdfs/regional-haze/entergy-ao-executed-8-7-2018.pdf.
---------------------------------------------------------------------------

    To the extent that the commenter is suggesting that EPA should 
acknowledge that approval will be required from the APSC because the 
lack of such approval would prevent Entergy from complying with the 
voluntary cessation of coal combustion, we note that Entergy has 
entered into an enforceable Administrative Order, which requires the 
cessation of coal combustion at White Bluff Units 1 and 2 by December 
31, 2028. In this final action, we are approving the Administrative 
Order as part of the SIP, and it is now therefore federally enforceable 
as a source-specific requirement. If Entergy does not comply with the 
terms of the Administrative Order, such as not ceasing coal combustion 
by December 31, 2028, Entergy will be in violation of the SIP, which is 
a federal requirement. Under Section 113 of the CAA (42 U.S.C. 7413), 
which addresses, among other things, federal enforcement of SIPs, EPA 
has the authority to enforce the terms of the Entergy Administrative 
Order, such as ceasing coal combustion by December 31, 2028, that are 
being incorporated into Arkansas' SIP here. In addition, under Section 
304 of the CAA (42 U.S.C. 7604), citizens and/or citizens groups have 
the authority to enforce emission limitations in orders, such as the 
provisions within the Entergy Administrative Order, or require EPA to 
do so, through the notice of the CAA citizens' suit process.
    Comment: Entergy's five factor analysis for White Bluff does not 
take into account any electric reliability or energy supply impacts 
arising from Entergy's voluntary decision to prematurely close White 
Bluff, which ultimately will require the replacement of White Bluff's 
firm electric generating capacity, not only for Entergy but also for 
the other White Bluff co-owners. This factor should have been 
considered in the five-factor analysis for White Bluff.
    Response: The commenter is correct that Entergy's BART analysis for 
White Bluff, which is part of the SIP revision, and on which ADEQ based 
its BART determination for White Bluff, did not identify any electric 
reliability or energy supply impacts arising from Entergy's voluntary 
decision to cease coal combustion at White Bluff. We note that the 
energy and nonair quality environmental impacts of compliance is one of 
the factors that the CAA and the Regional Haze rule require to be 
considered in the BART analysis.\42\ However, neither Entergy in its 
BART analysis nor ADEQ in the SIP revision identify any adverse energy 
and nonair quality environmental impacts associated with Entergy's 
enforceable measure to cease coal combustion at White Bluff prior to 
the end of the effective useful life of the facility, or with any other 
BART control option evaluated. EPA is also not aware of any such 
adverse impacts, and we therefore defer to ADEQ's determination that 
there are no significant energy impacts to consider in the five-factor 
BART analysis for White Bluff.
---------------------------------------------------------------------------

    \42\ See Sec.  51.308(e)(1)(ii)(A) and CAA section 169A(g)(2).
---------------------------------------------------------------------------

B. Reasonable Progress

    Comment: EPA's proposed approval of ADEQ's reasonable progress 
analysis and conclusions for the Independence facility are arbitrary, 
capricious, and contrary to law. Dry scrubbers at Independence are 
highly cost-effective when considering other regional haze actions in 
Arkansas and elsewhere, and thus EPA's and ADEQ's consideration of cost 
is arbitrary and unlawful. EPA should revise its proposed rule to find 
that dry scrubbers at Independence are cost-effective and should be 
required under reasonable progress.
    Response: We disagree with the commenter that our proposed approval 
of ADEQ's reasonable progress analysis and conclusions for the 
Independence facility for the first implementation period are 
arbitrary, capricious, or contrary to law. We do not contest that the 
cost effectiveness of dry scrubbers at Independence on a dollar per ton 
reduced ($/ton) basis is within the range of what other states and EPA 
have found reasonable for reasonable progress controls. However, in 
this action we evaluated ADEQ's reasonable progress analysis and 
conclusions and determined that it was not unreasonable for the State 
to conclude that dry scrubbers for Independence are not necessary to 
make reasonable progress.
    We noted in our proposal that Arkansas considered the capital costs 
of dry scrubbers and wet scrubbers to be high even though the costs in 
terms of $/ton of SO2 emissions reduced for both dry and wet 
scrubbers at the Independence facility (assuming a 30-year remaining 
useful life) are within a range that has been found to be cost-
effective in other regional haze actions.\43\ However, Arkansas' 
reasonable progress determination was not just based on the 
consideration of the cost-effectiveness of controls. Arkansas' 
reasonable progress determination with respect to the Independence 
facility was appropriately based on its consideration and weighing of 
the costs of compliance along with the other reasonable progress 
factors, as

[[Page 51041]]

well as visibility, which the state deemed to be a relevant factor for 
consideration in its analysis. Arkansas discussed its concerns 
regarding the cost of scrubber controls,\44\ noted that the evaluation 
of the $/dv metric demonstrated a greater difference in cost between 
dry FGD and low sulfur coal compared to the $/ton metric, and 
ultimately concluded that all the controls it evaluated would cost 
millions of dollars for what it considers to be little visibility 
benefit. We explained in our proposal that we believe that Arkansas' 
weighing of the four statutory factors and other factors it deemed 
relevant in its reasonable progress analysis for the Independence 
facility was reasonable and within the state's discretion.\45\ 
Furthermore, we note that our 2007 Reasonable Progress Guidance allows 
for the deferral of emission reductions to later planning periods, 
which ADEQ cites in its SIP,\46\ in deciding what amount of emissions 
reduction is appropriate in setting the RPGs considering that the long-
term goal of no manmade impairment encompasses several planning 
periods.\47\ We are finding here that considering all the above, 
including the state's concerns about the cost of controls \48\ and 
given that the state is requiring Independence Units 1 and 2 to switch 
to low sulfur coal within 3 years under the long-term strategy, which 
is expected to reduce SO2 emissions and result in visibility 
improvements at Arkansas' Class I areas, it is not unreasonable for 
Arkansas to weigh the factors in the way that it did and conclude that 
no SO2 controls under the reasonable progress requirements 
are necessary for the Independence facility in the first implementation 
period. We are finalizing our approval of Arkansas' reasonable progress 
determination with respect to the Independence facility and all other 
Arkansas sources.
---------------------------------------------------------------------------

    \43\ See 83 FR 62230.
    \44\ As discussed in our proposal, in light of Entergy's 
anticipated cessation of coal combustion at the Independence 
facility, although it is not state- or federally-enforceable, 
Arkansas considered it important to take into account the capital 
cost of controls along with the cost-effectiveness in terms of 
dollars per ton of emissions reduced. In its consideration of the 
cost of compliance, Arkansas also took into account that these costs 
would be passed on to Arkansas ratepayers. See 83 FR 62230.
    \45\ 83 FR 62233.
    \46\ See pages 28-53 of Arkansas Final Regional Haze Phase II 
SIP. https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20070601_wehrum_reasonable_progress_goals_reghaze.pdf.
    \47\ See Section 1.2 of EPA's ``Guidance for Setting Reasonable 
Progress Goals under the Regional Haze Program'' (June 1, 2007). 
https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20070601_wehrum_reasonable_progress_goals_reghaze.pdf.
    \48\ EPA is revising its assessment of ADEQ's consideration of 
capital costs in the state's reasonable progress determination for 
Independence. We are clarifying that our evaluation and conclusion 
in this final action that Arkansas' reasonable progress 
determination is reasonable does not rely on Arkansas' consideration 
of capital costs because Arkansas' decision to consider the capital 
costs of scrubber controls in its analysis was based on Entergy's 
anticipated early cessation of coal combustion at the Independence 
facility, which is not state- or federally-enforceable. However, EPA 
continues to find that ADEQ's determination is reasonable based on 
the totality of the circumstances.
---------------------------------------------------------------------------

    Comment: The proposed reasonable progress determination with 
respect to the Independence facility is arbitrary, capricious, and 
contrary to law because EPA's and ADEQ's reliance on the visibility 
``glidepath'' is an excuse for avoiding pollution reductions and is 
unlawful. ADEQ unlawfully concluded that no additional controls are 
required at Independence largely because the state is on the 
``glidepath'' toward natural visibility in distant decades. However, 
the glidepath is not an independently enforceable requirement and being 
``on the glidepath'' does not relieve the state of conducting a 
reasoned analysis. EPA should revise its proposed rule to make clear 
that ADEQ's reliance on the ``glidepath'' as an excuse to allow 
unabated air pollution from the Independence facility is unlawful and 
unreasonable.
    Response: We disagree with the commenter that ADEQ concluded that 
no additional controls are required at Independence because the state's 
Class I areas are on the glidepath. Instead, ADEQ's determination on 
reasonable progress with respect to the Independence facility was based 
on its consideration and weighing of the four reasonable progress 
factors, as well as consideration of potential visibility benefit of 
controls, which the state deemed to be a relevant factor for 
consideration in its analysis. We noted in our proposal that the 
statutory factor that appears to have been the most significant in 
Arkansas' reasonable progress determination with respect to the 
Independence facility is the cost of compliance, along with 
consideration of visibility benefits.\49\ As such, we disagree that 
ADEQ's determination was based solely or primarily on the fact that the 
state's Class I areas are on the glidepath toward natural visibility. 
Regardless of any consideration Arkansas might have placed on the fact 
that the state's Class I areas are on the glidepath in making its 
reasonable progress determination, our proposed and final approval is 
not based on the Class I areas' position with respect to the glidepath. 
We explained in our proposal that considering the state's concerns 
about the cost of the evaluated controls \50\ and given that the state 
is requiring Independence Units 1 and 2 to switch to low sulfur coal 
within 3 years under the long-term strategy, which is expected to 
reduce SO2 emissions and result in visibility improvements 
at Arkansas' Class I areas, we found that it is not unreasonable for 
Arkansas to conclude that SO2 controls under the reasonable 
progress requirements are not necessary for the Independence facility 
in the first implementation period.\51\ Our proposal further stated 
that one of the components forming the basis of our proposed approval 
is ``the state's evaluation and reasonable weighing of the four 
statutory factors along with consideration of the visibility benefits 
of controls for the Independence facility.'' \52\ As is evident from 
our discussion of ``degree of improvement in visibility'' in the 
proposal, ADEQ considered the potential visibility benefits of controls 
in its analysis of controls for Independence, as opposed to visibility 
conditions in relation to the glidepath.\53\ We did not point to the 
glidepath as a basis for our approval of the state's reasonable 
progress analysis and determination. Therefore, the commenter is 
incorrect in contending that EPA is relying on the visibility glidepath 
as a reason for not requiring pollution reductions at the Independence 
facility.
---------------------------------------------------------------------------

    \49\ 83 FR 62232.
    \50\ As explained elsewhere in this section of the notice, EPA 
is revising its assessment of ADEQ's consideration of capital costs 
in the state's reasonable progress determination for Independence. 
However, EPA continues to find that ADEQ's determination is 
reasonable based on the totality of the circumstances.
    \51\ 83 FR 62233.
    \52\ 83 FR 62233.
    \53\ 83 FR 62229.
---------------------------------------------------------------------------

    Comment: ADEQ cites the high capital costs of new scrubbers as a 
basis for declining to require them for the Independence facility. This 
is inappropriate because the capital costs are already assessed in the 
calculation of cost-effectiveness and the rejection of a control on the 
basis of capital costs neglects consideration of the benefits of that 
control, which could justify that cost.
    Response: While the commenter is correct that Arkansas considered 
capital costs in its four-factor analysis and that its reasonable 
progress determination was based in part on the capital cost of 
controls, this was not the only factor Arkansas considered and based 
its decision on. Arkansas considered the cost of controls in the form 
of cost-effectiveness ($/ton) and capital costs, in addition to also 
considering the remaining reasonable progress factors

[[Page 51042]]

and the anticipated visibility improvement of controls, as it deemed 
consideration of visibility to be a relevant factor in its reasonable 
progress analysis. Arkansas noted that the evaluation of the $/dv 
metric demonstrated a greater difference in cost between dry FGD and 
low sulfur coal compared to the $/ton metric, and ultimately concluded 
that the controls it evaluated would cost millions of dollars for what 
it considers to be little visibility benefit. Thus, Arkansas' 
reasonable progress determination with respect to the Independence 
facility was based on its consideration and weighing of the costs of 
compliance and the other reasonable progress factors, as well as 
visibility.
    We do note that based on comments we received and having given the 
matter further consideration, we realize that Arkansas' consideration 
of capital costs in the four-factor analysis for the Independence 
facility is not appropriate because the state's decision to consider 
capital costs was rooted in Entergy's anticipated early cessation of 
coal combustion at the Independence facility, which is not state- or 
federally-enforceable. Considering the capital costs of controls in 
this context would be equivalent to inappropriately assuming a shorter 
remaining useful life for Independence in the cost-effectiveness 
calculation based on an unenforceable measure to change future 
operations. Therefore, we are clarifying that our evaluation and 
conclusion in this final action that Arkansas' reasonable progress 
determination is reasonable does not rely on Arkansas' consideration of 
capital costs. EPA's long-standing position in other regional haze 
actions is that consideration of certain cost metrics such as capital 
costs and $/dv are not appropriate bases for rejecting controls that 
would have otherwise been determined to be reasonable. However, given 
the totality of the circumstances in this case, including the SIP's 
requirement for Independence Units 1 and 2 to switch to low sulfur coal 
within 3-years under the long-term strategy, the anticipated emissions 
reductions due to the implementation of BART controls required by the 
SIP revision,\54\ and the anticipated cessation of coal combustion at 
Independence by the end of 2030, we continue to find that Arkansas 
reasonably exercised its discretion in determining that no 
SO2 controls are necessary under reasonable progress for the 
Independence facility in the first implementation period. We do note 
that we are merely clarifying the basis for our approval of Arkansas' 
reasonable progress determination, but the outcome of our evaluation 
and our decision to approve the state's reasonable progress 
determination remain unchanged from proposal.
---------------------------------------------------------------------------

    \54\ See ``Arkansas Regional Haze SO2 and PM SIP 
Revision,'' section V.E, page 53.
---------------------------------------------------------------------------

    Comment: EPA should disapprove Arkansas' method of identifying 
sources for further analysis under reasonable progress because Arkansas 
failed to appropriately evaluate area sources, in particular 
concentrated animal feeding operations (CAFO's). This is despite clear 
evidence in the record that area sources, such as CAFO's, are a 
significant part of the haze problem in Arkansas. CAFO's, which are a 
source of ammonia emissions, are likely a significant contributor to 
haze in Arkansas and ADEQ should have evaluated the cost-effectiveness 
of controlling emissions from these sources.
    Response: We disagree with the commenter that Arkansas' reasonable 
progress analysis was inappropriate with respect to its treatment of 
area sources, which includes CAFO's. EPA's Guidance for Setting 
Reasonable Progress Goals Under the Regional Haze Program (EPA's 
Reasonable Progress Guidance) provides that the reasonable progress 
analysis involves identification of key pollutants and source 
categories that contribute to visibility impairment at the Class I 
area.\55\ The guidance provides that once the key pollutants 
contributing to visibility impairment at each Class I area have been 
identified, the sources or source categories responsible for emitting 
these pollutants or pollutant precursors can also be determined.\56\ 
The reasonable progress factors are then to be applied to the key 
pollutants and sources or source categories contributing to visibility 
impairment at each affected Class I area.
---------------------------------------------------------------------------

    \55\ See EPA's ``Guidance for Setting Reasonable Progress Goals 
under the Regional Haze Program'' (June 1, 2007), page 3-1. The 
guidance document can be found at the following link: https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20070601_wehrum_reasonable_progress_goals_reghaze.pdf.
    \56\ See EPA's ``Guidance for Setting Reasonable Progress Goals 
under the Regional Haze Program'' (June 1, 2007), page 3-1.
---------------------------------------------------------------------------

    The approach taken by Arkansas in its reasonable progress analysis 
involved an assessment of both region-wide Particulate Source 
Apportionment Technology (PSAT) data and PSAT data for Arkansas 
sources.\57\ Based on this assessment, Arkansas identified sulfate 
(SO4) as the key species contributing to light extinction at 
Caney Creek and Upper Buffalo. Arkansas further determined that the 
primary driver of SO4 formation is emissions of 
SO2 from point sources both region-wide and in Arkansas. As 
such, Arkansas decided to focus on point sources emitting at least 250 
tpy of SO2 to determine whether their emissions and 
proximity to Arkansas Class I areas warranted further analysis using 
the four statutory factors. Arkansas did assert that when all source 
categories within Arkansas are considered, light extinction due to 
Arkansas area sources is greater compared to the light extinction due 
to Arkansas point sources at both Caney Creek and Upper Buffalo on the 
20% worst days in 2002. However, Arkansas explained that the cost of 
controlling many individual small area sources may be difficult to 
quantify. CAFO's fall under the category of small area sources and it 
is therefore likely that Arkansas would find it difficult to quantify 
the cost of controlling emissions from CAFO's. While we acknowledge the 
commenter's concerns regarding the visibility impact of ammonia 
emissions from CAFO's, we note the BART Guidelines provide that states 
should use their best judgment in deciding whether ammonia emissions 
from a source are likely to have an impact on visibility in an area, as 
controlling ammonia emissions in some areas may not have a significant 
impact on visibility.\58\ The BART Guidelines further provide that 
given that air quality modeling may not be feasible for individual 
sources of ammonia, states should also exercise their judgement in 
assessing the degree of visibility impacts due to emissions of ammonia 
or ammonia compounds.\59\ Since our 2007 Reasonable Progress Guidance 
does not itself provide recommendations on how sources of ammonia 
should be addressed in the reasonable progress analysis, we believe it 
would be reasonable for states to rely on the BART Guidelines in this 
instance for addressing ammonia emissions under the reasonable progress 
analysis. Therefore, we find that Arkansas' decision not to evaluate 
sources of ammonia emissions in its reasonable progress analysis to be 
reasonable. We find that Arkansas has provided a reasoned basis for the 
approach it took

[[Page 51043]]

to identify sources for further consideration in the reasonable 
progress analysis and we find that it is reasonable for Arkansas to 
arrive at the decision not to further examine area sources in its 
reasonable progress analysis for the first implementation period. We 
also note that states may prioritize their planning in the manner that 
best suits their circumstances, so long as they demonstrate that their 
prioritization is reasonable given the statutory requirement to make 
reasonable progress. Our 2007 Reasonable Progress Guidance provides 
that states may wish to defer emission reductions to later planning 
periods, which ADEQ cites in its SIP,\60\ since the long-term goal of 
no manmade impairment encompasses several planning periods.\61\ We find 
that ADEQ has appropriately decided to focus on the point source 
category for evaluation of SO2 emissions reductions in the 
reasonable progress analysis for the first planning period. In future 
planning periods, it may be appropriate for Arkansas to reevaluate the 
benefit of addressing emissions from area sources, which will likely 
become more important as emissions from other source categories are 
reduced.
---------------------------------------------------------------------------

    \57\ As part of its reasonable progress analysis, ADEQ provided 
a discussion of the results of air quality modeling performed by the 
Central Regional Air Planning Association (CENRAP) in support of SIP 
development in the central states region. The CENRAP modeling 
included Particulate Source Apportionment Technology Tool (PSAT) 
with CAMx version 4.4, which was used to provide source 
apportionment by geographic regions and major source categories for 
pollutants that contribute to visibility impairment at each of the 
Class I areas in the central states region.
    \58\ 40 CFR part 51, appendix Y, II(A)(3).
    \59\ 40 CFR part 51, appendix Y, II(A)(3).
    \60\ See pages 28-53 of Arkansas Final Regional Haze Phase II 
SIP. https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20070601_wehrum_reasonable_progress_goals_reghaze.pdf.
    \61\ See Section 1.2 of EPA's ``Guidance for Setting Reasonable 
Progress Goals under the Regional Haze Program'' (June 1, 2007). 
https://www3.epa.gov/ttn/naaqs/aqmguide/collection/cp2/20070601_wehrum_reasonable_progress_goals_reghaze.pdf.
---------------------------------------------------------------------------

    Comment: Although the commenter supports EPA's proposal to approve 
ADEQ's reasonable progress determination, which requires no additional 
controls on sources in Arkansas for the first planning period, the 
commenter believes that a four-factor analysis was not required because 
controls are not necessary to ensure reasonable progress for the first 
planning period. The threshold issue when addressing reasonable 
progress is whether further actions are necessary to ensure that 
visibility improvement is continuing toward background levels (i.e., on 
or below the uniform rate of progress (URP)). Since Arkansas' Class I 
areas are below the URP and are already meeting the RPGs Arkansas 
established in the SIP revision, a reasonable progress analysis was not 
required.
    Response: While we appreciate the commenter's support of our 
proposed approval of Arkansas' reasonable progress determination, we 
disagree with the commenter that it was not necessary for Arkansas to 
conduct a reasonable progress analysis for the first implementation 
period. The Clean Air Act requires that states' SIPs contain a long-
term strategy for making reasonable progress, and that in determining 
reasonable progress states must consider the very four-factor analysis 
which the commenter purports is not needed. The Regional Haze Rule 
implements the statutory requirements and provides that states must 
determine whether controls are necessary to ensure reasonable progress 
based on four statutory factors. The preamble to the 1999 Regional Haze 
Rule states that ``. . . EPA is not specifying in this final rule what 
specific control measures a State must implement in its initial SIP for 
regional haze. That determination can only be made by a State once it 
has conducted the necessary technical analyses of emissions, air 
quality, and the other factors that go into determining reasonable 
progress.'' \62\ The Regional Haze Rule clearly states that the 
technical analysis of the four factors that determines what is 
necessary for reasonable progress occurs prior to a reasonable progress 
determination, including in cases where the reasonable progress 
determination is that no further controls are required under reasonable 
progress.\63\
---------------------------------------------------------------------------

    \62\ 64 FR 35721.
    \63\ See 64 FR 35714 at 35721 and 35731-35735 and 35734 (July 1, 
1999).
---------------------------------------------------------------------------

    CAA section 169A(g)(1) provides that reasonable progress is 
determined by consideration of (1) the costs of compliance, (2) the 
time necessary for compliance, (3) the energy and nonair quality 
environmental impacts of compliance, and (4) the remaining useful life 
of any existing source subject to such requirements. The Regional Haze 
regulations under Sec.  51.308(d)(1)(i)(A) also require consideration 
of these four statutory factors when establishing the RPGs for a Class 
I area, along with a demonstration showing how these factors were taken 
into consideration in selecting the goal.
    The statute and regulations are both clear that the states have the 
authority and obligation to evaluate the four reasonable progress 
factors and that the decision regarding the controls required to make 
reasonable progress and the subsequent establishment of the RPGs must 
be based on these factors identified in CAA section 169A(g)(1) and the 
Regional Haze regulations under Sec.  51.308(d)(1)(i)(A). The URP 
framework is not based on the four statutory factors, but is instead an 
analytical tool created by extrapolating emission reductions from the 
mid-1990s through approximately 2005 into the future.\64\ While Sec.  
51.308(d)(1)(i)(B) of the Regional Haze regulations requires that a 
state also consider the URP glidepath in establishing the RPGs, this 
does not mean that no further analysis or controls are required as long 
as a state's Class I areas are below the URP, as the commenter 
contends. In fact, the preamble to the 1999 Regional Haze Rule 
reinforces that the amount of progress that is reasonable is defined 
based on the statutory factors, notwithstanding the URP.\65\ Clearly, a 
state's obligation to evaluate the four statutory factors and set RPGs 
based on CAA section 169A(g)(1) and Sec.  51.308(d)(1) applies in all 
cases, without regard to the Class I area's position relative to the 
URP. There is nothing in the CAA or Regional Haze regulations that 
suggests that a state's obligation to ensure reasonable progress can be 
met by just meeting the URP.\66\
---------------------------------------------------------------------------

    \64\ See 64 FR 35731-35733.
    \65\ 64 FR 35732.
    \66\ See 77 FR 14604, at 14629.
---------------------------------------------------------------------------

    We note that our conclusion here is consistent with our final 
action on the 2008 Arkansas Regional Haze SIP, where we disapproved 
Arkansas' RPGs and found that Arkansas had not met its reasonable 
progress obligations precisely because the state established its RPGs 
without conducting an evaluation of the four statutory factors and did 
so based on the fact that its Class I areas were below the URP 
glidepath. In the preamble to our final action on the 2008 Arkansas 
Regional Haze SIP, we were clear that an evaluation of the four 
statutory factors is required regardless of the Class I area's position 
relative to the URP glidepath:

    [B]eing on the ``glidepath'' does not mean a state is allowed to 
forego an evaluation of the four statutory factors when establishing 
its RPGs. Based on an evaluation of the four statutory factors, 
states may determine that RPGs that provide for a greater rate of 
visibility improvement than would be achieved with the URP for the 
first implementation period are reasonable.\67\
---------------------------------------------------------------------------

    \67\ 77 FR 14629.

    Our final action on the Arkansas Regional Haze SIP was published in 
the Federal Register on March 12, 2012, and became effective on April 
11, 2012. Our final action disapproving Arkansas' reasonable progress 
determination and RPGs and our position with regard to the URP was not 
challenged. We reiterate in this final action that the CAA and Regional 
Haze regulations require an analysis of the four reasonable progress 
factors regardless of a Class I area's position relative to the URP and 
that being below the glide path

[[Page 51044]]

does not automatically mean that no controls are necessary under 
reasonable progress.
    With regard to the commenter's argument that it was not necessary 
for Arkansas to conduct a four-factor analysis given that Arkansas 
Class I areas are already meeting the RPGs established in the SIP 
revision, we note first that this is a circular argument. The numeric 
RPGs are calculated by taking into account the visibility improvement 
anticipated from enforceable emission limitations and other control 
measures (including BART, reasonable progress, and other ``on the 
books'' controls). Thus, the RPGs for the first planning period 
represent the best estimate of the degree of visibility improvement 
that will result in 2018 from changes in emissions inventories, changes 
driven by the particular set of control measures the state has adopted 
in its regional haze SIP to address visibility, as well as all other 
enforceable measures expected to reduce emissions over the period of 
the SIP from 2002 to 2018.\68\ To argue that a four-factor analysis is 
not needed because the RPGs, which are based in part on the outcome of 
that very four-factor analysis, are at a certain level is circular. 
Furthermore, the Regional Haze Rule provides that the emission 
limitations and control measures established under BART and under the 
reasonable progress determinations are what is enforceable, not the 
RPGs themselves.\69\ EPA cannot enforce an RPG in the sense of seeking 
to apply penalties on a state for failing to meet the RPG or obtaining 
injunctive relief to require a state to achieve its RPG. However, the 
long-term strategy can and must contain emission limits and other 
control measures that apply to specific sources, and that are 
themselves enforceable. Meeting or being projected to meet the RPG does 
not automatically demonstrate that a state has satisfied its 
requirements under BART and reasonable progress.
---------------------------------------------------------------------------

    \68\ 64 FR 35733.
    \69\ 64 FR 35733.
---------------------------------------------------------------------------

    Comment: The commenter supports EPA's proposal to approve ADEQ's 
reasonable progress determination, which requires no additional 
controls on sources in Arkansas for the first planning period. However, 
Arkansas' reasonable progress analysis ``broadly applicable'' to 
Arkansas sources was sufficient to satisfy the reasonable progress 
requirements and Arkansas surpassed the CAA requirements when it 
nonetheless undertook an analysis that applied the four reasonable 
progress factors to the Independence facility. EPA inappropriately 
proposed to conclude that the broad analysis was merely ``informative'' 
and ``not a determinative component of the state's reasonable progress 
analysis.'' Even if a four-factor analysis were necessary in this case, 
ADEQ's broad analysis was sufficient to satisfy its reasonable progress 
obligations, making a site-specific four-factor analysis for 
Independence unnecessary. ADEQ's broad approach was appropriate, as 
there is no requirement that a reasonable progress analysis be 
performed on a source-specific basis. EPA should conclude that this 
broad analysis was sufficient and rendered further analysis, including 
any source-specific four-factor analysis, unnecessary.
    Response: While we appreciate the commenter's support of our 
proposed approval of ADEQ's reasonable progress determination, we 
disagree with the commenter that the broad analysis included in ADEQ's 
SIP revision satisfies this reasonable progress obligation and note 
that it is not a basis for our approval of ADEQ's reasonable progress 
analysis. While it may not be necessary to conduct a source-specific 
analysis of the four factors in all instances to satisfy the reasonable 
progress obligations,\70\ we do not agree that the broad analysis 
provided in ADEQ's SIP revision complies with the applicable statutory 
and regulatory requirements. As discussed further below, the broad 
analysis of a group of sources provided by ADEQ in the SIP revision 
does not clearly identify any sources or controls that were evaluated 
in the state's weighing of the costs and other statutory factors nor 
did it estimate in specific numeric form the cost of controls, making 
it clear that the dispositive consideration in the broad analysis was 
visibility conditions with respect to the URP.\71\ Therefore, we find 
that the broad analysis presented in the SIP revision does not satisfy 
Arkansas' reasonable progress obligations. ADEQ's broad analysis does 
not discuss pollutants or identify possible specific controls for these 
pollutants or for source categories for these pollutants. Instead, in 
evaluating the costs of compliance, the broad analysis discusses in a 
very generic manner the anticipated impact of additional costs of 
compliance on the health and vitality of industries within the state 
and on Arkansas ratepayers, without ever even identifying the potential 
controls or discussing actual cost estimates.
---------------------------------------------------------------------------

    \70\ On the contrary, we discussed in our proposal that we agree 
that an approach that involves a broad analysis of groups of sources 
or source categories may be appropriate in certain cases, as 
provided by EPA's Reasonable Progress Guidance. 83 FR 62232.
    \71\ 83 FR 62232.
---------------------------------------------------------------------------

    Moreover, ADEQ itself deemed the application of the four factors to 
the Independence facility necessary, stating in the SIP revision that 
``due to the circumstances of the 2016 AR RH FIP, which applied the 
factors to a single facility, Independence, ADEQ has determined that 
application of the four factors to the specific source analyzed by EPA 
is also ``relevant.'' \72\ The SIP revision further explains that for 
this reason, ``ADEQ has performed both a broader analysis using the 
four factors as well as a more narrow analysis specific to Independence 
before determining whether any controls are necessary.'' \73\ ADEQ did 
not reach a final determination regarding reasonable progress until 
after evaluating large point sources individually to identify sources 
for potential further evaluation under the four reasonable progress 
factors and conducting a more narrow and focused analysis on those 
sources. In this case, one source was identified for further evaluation 
under the four reasonable progress factors, specifically, the 
Independence facility. Therefore, we are concluding that the state's 
broad analysis of a group of sources was not a determinative component 
of the state's reasonable progress analysis. We appreciate the 
thoroughness of the state's reasonable progress analysis but reiterate 
and clarify, as necessary, here that the broad analysis is not a 
component of our finding that the state has satisfied the reasonable 
progress requirements.\74\
---------------------------------------------------------------------------

    \72\ See ``Arkansas Regional Haze SO2 and PM SIP 
Revision,'' section V, page 30.
    \73\ See ``Arkansas Regional Haze SO2 and PM SIP 
Revision,'' section V, page 30.
    \74\ See 83 FR 62233 (laying out the four components of ADEQ's 
reasonable progress analysis on which EPA based its proposed 
approval).
---------------------------------------------------------------------------

    Although we disagree with the commenter that the broad analysis 
included in ADEQ's SIP revision satisfies Arkansas' reasonable progress 
obligations, we are finalizing our proposed approval of ADEQ's 
reasonable progress determination based on the following: (1) The 
state's discussion of the key pollutants and source categories that 
contribute to visibility impairment in Arkansas' Class I areas per the 
CENRAP's source apportionment modeling; (2) the state's identification 
of a group of large SO2 point sources in Arkansas for 
potential evaluation of controls under reasonable progress; (3) the 
state's rationale for narrowing down its list of potential sources to 
evaluate under the reasonable progress requirements; and (4) the 
state's evaluation and reasonable

[[Page 51045]]

weighing of the four statutory factors along with consideration of the 
visibility benefits of controls for the Independence facility.
    Comment: No additional controls can be considered for reasonable 
progress at sources in Arkansas since no controls could be implemented 
before the end of the first planning period in 2018. EPA's regulations 
require SIPs to consider ``the emission reduction measures needed to 
achieve [reasonable progress goals] for the period covered by the 
implementation plan.'' 40 CFR 51.308(d)(1)(i)(B). In staying the 
effectiveness of EPA's Regional Haze FIP for the state of Texas, the 
U.S. Court of Appeals for the Fifth Circuit explained that ``[t]he 
emissions controls included in a state implementation plan . . . must 
be those designed to achieve the reasonable progress goal for the 
period covered by the plan,'' and that the parties challenging the FIP 
``persuasively argue that [EPA's requirement that power plants meet 
Reasonable Progress goals by installing scrubbers in 2019 and 2021] 
exceeds the power granted by the Regional Haze Rule.'' Texas v. EPA, 
829 F.3d 405, 429 (5th Cir. 2016) (internal citations omitted). It is 
therefore inappropriate to require reasonable progress controls in a 
SIP for the first planning period when the controls cannot be installed 
or result in visibility benefits in that planning period.
    Response: The Fifth Circuit stay decision cited by the commenter 
suggested that it was likely that the EPA had exceeded its statutory 
authority by imposing emission controls that go into effect after the 
end of the implementation period in the Texas Regional Haze FIP. This 
assessment is incorrect. First, we note that the decision, by a Fifth 
Circuit motions panel, did not cite to a provision of the CAA to 
support the proposition that the EPA exceeded its statutory authority, 
as the CAA contains no such constraint. Subsequent to the Fifth Circuit 
decision to grant a stay of the EPA's Texas FIP, EPA finalized its 
revisions to the Regional Haze Rule, and, in the process, clarified its 
long-standing interpretation of the relationship between long-term 
strategies and RPGs. As stated in the final rule, ``portions of the 
stay decision indicate a fundamental misunderstanding of aspects of the 
visibility program and the EPA's action on the Oklahoma and Texas 
regional haze SIPs.'' 82 FR 3078, 3087 (January 10, 2017). CAA section 
169A(b)(2)(B) requires that SIPs include ``a long-term (ten to fifteen 
years) strategy for making reasonable progress toward meeting the 
national goal.'' In our rulemaking, we noted that ``ten to fifteen 
years'' was ambiguous and could either mean that the long-term strategy 
must be updated every ten to fifteen years or that it must be fully 
implemented within ten to fifteen years. To impose the latter 
interpretation would restrict states' or the EPA's ability to require 
controls that could not be fully implemented before the end of the 
implementation period and would incentivize states to delay the 
submission of a regional haze SIP since they could essentially ``run 
out the clock.'' Further, EPA's 2007 reasonable progress guidance 
specifically recognized that the time needed for full implementation of 
a control measure might extend beyond the end of the implementation 
period.\75\ Additionally, EPA does not lose its authority to regulate 
after a deadline, even a mandatory deadline, has passed; rather, the 
appropriate remedy is a court order compelling the agency to fulfill 
the regulatory obligation. For a more in-depth discussion on this 
issue, please see our final rule at 82 FR 3078, 3087-3089.
---------------------------------------------------------------------------

    \75\ See Guidance for Setting Reasonable Progress Goals under 
the Regional Haze Program, June 1, 2007.
---------------------------------------------------------------------------

    Comment: Although EPA should finalize its approval of ADEQ's 
reasonable progress determination, EPA's analysis of the application of 
DSI and enhanced DSI at the Independence facility should not be part of 
EPA's final action. ADEQ did not assess these two control technologies 
in its four-factor analysis for Independence, nor was it required to. 
Therefore, EPA's DSI and enhanced DSI analyses are inappropriate and 
extraneous and should not be included in the final action, as EPA has 
no authority under the CAA to substitute its judgment for that of the 
state's. Nevertheless, the commenter does agree that DSI and enhanced 
DSI are not required under reasonable progress.
    Response: We appreciate the commenter's support of our proposal to 
approve ADEQ's reasonable progress determination. While ADEQ's decision 
to not evaluate DSI or enhanced DSI at the Independence facility does 
not change the result of the state's determination and we are therefore 
approving that determination here, we disagree that our analysis of DSI 
and enhanced DSI at Independence should not be part of our final 
action. As we explained in our proposal, since the White Bluff and 
Independence facilities are sister facilities with nearly identical 
units and comparable levels of annual SO2 emissions, and 
since both DSI and enhanced DSI were evaluated in the BART analysis for 
White Bluff Units 1 and 2, we find it appropriate to consider these 
controls in the four-factor analysis for the Independence facility as 
well.\76\ However, neither the SIP revision nor Entergy's four factor 
analysis for controls on the Independence facility considered DSI or 
enhanced DSI as control options. Therefore, we provided this 
information in our proposal to demonstrate that even if ADEQ had 
considered DSI and enhanced DSI in its reasonable progress analysis for 
the Independence facility, it likely would not have changed the state's 
final determination on reasonable progress.\77\ We note that we 
estimated the cost-effectiveness of DSI and enhanced DSI at the 
Independence facility by relying on Entergy's estimates of the capital 
costs and annual operation and maintenance costs of these controls for 
White Bluff. Thus, based on the results of our analysis of DSI and 
enhanced DSI, we do not consider the omission of consideration of DSI 
and enhanced DSI as control options for SO2 at the 
Independence facility to be an impediment to approving ADEQ's 
reasonable progress analysis. Without the results of our analysis of 
DSI and enhanced DSI for the Independence facility, we would not be 
able to arrive at the conclusion that ADEQ's omission did not impact 
our ultimate conclusion regarding the state's reasonable progress 
analysis. Therefore, we disagree with the commenter that our analysis 
of DSI and enhanced DSI for the Independence facility is unnecessary in 
our review and approval of ADEQ's reasonable progress analysis.
---------------------------------------------------------------------------

    \76\ 83 FR 62232.
    \77\ 83 FR 62232.
---------------------------------------------------------------------------

    Comment: The commenter agrees that Independence is not subject to 
BART, that no additional controls beyond use of low-sulfur coal at 
Independence are necessary to achieve reasonable progress and agrees 
with the adoption of low-sulfur coal as the long-term strategy for 
Independence.
    Response: We appreciate the commenter's support of our proposal 
with respect to the Independence facility and the long-term strategy.

C. Clean Air Act Section 110(l)

    Comment: EPA's proposed rule as a whole violates the Clean Air 
Act's ``anti-backsliding'' requirement, 42 U.S.C. 7410(l). Compared to 
the existing FIP, the State's plan would result in greater air 
pollution and greater visibility impairment at affected Class I areas. 
In the 2016 Arkansas FIP, EPA required Independence Units 1 and 2 to 
meet SO2 emission limits based on the use of new

[[Page 51046]]

scrubbers under the reasonable progress provisions. Now, EPA has 
proposed to approve a SIP revision that would replace those 
SO2 emission limits with much higher limits based on the use 
of low-sulfur coal. In addition, whereas the existing FIP requires 
White Bluff Units 1 and 2 to meet SO2 emission limits based 
on the use of new scrubbers, the proposed SIP revision would replace 
that requirement with a much higher emission limit based on the use of 
low sulfur coal. The SIP revision includes no reductions beyond those 
in the FIP that would compensate for allowing higher SO2 
emissions from both Independence and White Bluff. As a result, EPA's 
proposed rule would authorize significantly more SO2 
emissions and produce worse air quality than the existing FIP. Section 
110(l) of the Clean Air Act prohibits a plan revision that would weaken 
the existing FIP requirements in this manner. This increase in 
SO2 emissions under the SIP relative to the FIP violates the 
Clean Air Act's anti-backsliding provision, which prohibits plan 
revisions that would interfere with attainment of the NAAQS or other 
``applicable requirements'' of the Act and prohibits plan revisions 
that would interfere with an existing requirement to make reasonable 
further progress.
    Response: We disagree that our rulemaking violates the CAA's 
requirements under section 110(l). The commenter mischaracterizes CAA 
section 110(l)'s requirements. Section 110(l) states that, ``[t]he 
Administrator shall not approve a revision of a plan if the revision 
would interfere with an applicable requirement concerning attainment 
and reasonable further progress or any other applicable requirement of 
this chapter.'' First, the SIP revision will not interfere with the 
``applicable requirements'' of the regional haze program. The CAA 
requires that the SIP ``contain such emission limits, schedules of 
compliance and other measures as may be necessary to make reasonable 
progress toward meeting the national goal.'' The corresponding federal 
regulations found at 40 CFR 51.308 and appendix Y to part 51 detail the 
required process for determining the appropriate emission limits for 
the regional haze program. The State followed the prescribed process 
for determining the levels of control that are required for BART and 
reasonable progress. Our approval of the SIP revision is supported by 
our evaluation of the state's conclusions and our determination that 
the BART and reasonable progress requirements under the CAA are met. 
The rationale supporting that determination was presented in the notice 
of proposed rulemaking for this action.\78\ For these reasons, our 
final approval of the SIP revision and concurrent withdrawal of the 
corresponding parts of the FIP will not interfere with the CAA 
requirements for BART or reasonable progress.
---------------------------------------------------------------------------

    \78\ 83 FR 62204.
---------------------------------------------------------------------------

    Second, the SIP revision will not interfere with any applicable 
requirement concerning attainment and reasonable further progress. EPA 
interprets CAA section 110(l) as applying to all NAAQS that are in 
effect, including those that have been promulgated but for which EPA 
has not yet made designations. EPA has concluded that 110(l) can be 
satisfied by demonstrating that substitute measures ensure that status 
quo air quality is preserved. However, 110(l) can also be satisfied by 
an air quality analysis demonstrating that any change in emissions will 
not interfere with any applicable requirement concerning attainment and 
reasonable further progress, or any other applicable CAA requirement. 
Noninterference with attainment of the NAAQS may be demonstrated by an 
air quality analysis showing that any emission changes associated with 
the revision will not interfere with attainment of the NAAQS. This 
option requires a showing that the area (as well as interstate and 
intrastate areas downwind) can attain the NAAQS even with the plan in 
its revised form. See, e.g. Kentucky Resources Council, Inc. v. EPA, 
467 F.3d 986 (6th Cir. 2006).
    Though the commenter is correct in noting that the higher 
SO2 emission limits for White Bluff Units 1 and 2 contained 
in the SIP are replacing the more stringent SO2 emission 
limits contained in the FIP, the commenter fails to consider that the 
SIP revision contains an Administrative Order making enforceable 
Entergy's voluntary plans to cease coal combustion at White Bluff Units 
1 and 2 by December 31, 2028. Because the cessation of coal combustion 
will lead to emission reductions greater than the SO2 
emission reductions required for White Bluff under the FIP, the SIP 
revision with respect to the SO2 limits for White Bluff will 
clearly not interfere with attainment and reasonable further progress 
in the long term (i.e., after December 31, 2028).
    While it is true that the FIP included more stringent 
SO2 emission limits for Independence Units 1 and 2 than the 
SIP revision,\79\ there is no evidence that withdrawal of the 
SO2 limits in the FIP for White Bluff and Independence and 
the approval of the SO2 emission limits in the SIP revision 
will interfere with attainment of the SO2 NAAQS. At this 
time, and notwithstanding the fact that the FIP provisions have not 
gone into effect, the areas that would be potentially impacted by the 
increase in SO2 emissions allowed under the SIP revision as 
compared to the FIP are attaining the 1-hour SO2 NAAQS. 
Based on an assessment of current air quality in the areas most 
affected by this SIP revision, which we discuss in the paragraphs that 
follow, we are concluding that the near term less stringent 
SO2 emissions limits in the SIP will not interfere with 
attainment of the NAAQS. Jefferson County, where the White Bluff 
facility is located, was designated by EPA as ``attainment/
unclassifiable,'' for the 2010 1-hour SO2 NAAQS in a 
rulemaking signed on June 30, 2016.\80\ This area was able to attain 
the 2010 1-hour SO2 NAAQS without the emissions limits that 
were promulgated in the FIP being implemented. In the same June 30, 
2016 rulemaking, EPA designated Independence County, where the 
Independence facility is located, as ``unclassifiable'' for the 2010 1-
hour SO2 NAAQS.\81\ In a subsequent rulemaking signed on 
March 7, 2019, EPA approved the State of Arkansas' request to 
redesignate Independence County from unclassifiable to attainment/
unclassifiable based on a new modeling analysis provided by the 
State.\82\ In a rulemaking signed on December 21,

[[Page 51047]]

2017, EPA designated all remaining areas in Arkansas as attainment/
unclassifiable.\83\ On March 18, 2019, EPA finalized a rule which 
retained the 2010 1-hour SO2 standard. At the time that 
Independence County, Jefferson County, and all other areas in Arkansas 
were designated or redesignated as attainment/unclassifiable under the 
2010 1-hour SO2 NAAQS in June 2016, December 2017, and March 
2019, Independence Units 1 and 2 and White Bluff Units 1 and 2 were 
emitting SO2 at levels not restricted by SIP or FIP limits. 
So the establishment of the SIP limits based on low sulfur coal will 
not interfere with attainment of the SO2 NAAQS in the near 
term. In the long term, the cessation of coal combustion at White Bluff 
will result in more reductions in SO2 emissions than the FIP 
and will result in further improvement in air quality.
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    \79\ Entergy plans to cease coal combustion at Independence 
Units 1 and 2 by December 31, 2030, which we expect would result in 
comparable or greater SO2 emissions reductions than 
required for the Independence facility under the FIP. However, this 
planned cessation of coal combustion at the Independence units by 
the end of 2030 is not required under the SIP revision.
    \80\ The EPA's attainment/unclassifiable designation for 
Jefferson County was based on, among other things, our evaluation of 
the State's modeling that showed attainment, and which we concluded 
generally followed EPA guidance. See 81 FR 45039 (July 12, 2016).
    \81\ The EPA's unclassifiable designation for Independence 
County was based on, among other things, our evaluation of the 
State's air dispersion modeling analysis, as well as the additional 
modeling analysis submitted by environmental groups for the area 
surrounding the Independence Steam Electric Station. Based on our 
evaluation of these analyses and our consideration of all available 
data and information, the EPA determined that the area cannot be 
classified as meeting or not meeting the NAAQS based on information 
available at the time. See 81 FR 45039 (July 12, 2016).
    \82\ EPA determined that the modeling analysis submitted by the 
State appropriately characterized the air quality in Independence 
County, Arkansas, and predicted that ambient SO2 
concentrations are below the 1-hour SO2 NAAQS. See 84 FR 
8986 (March 13, 2019).
    \83\ The EPA's designations for remaining areas in the state 
were based on an assessment and characterization of air quality 
through ambient air quality data, air dispersion modeling, other 
evidence and supporting information, or a combination of the above. 
See 83 FR 1098 (January 9, 2018).
---------------------------------------------------------------------------

    Since sulfate is a precursor to particulate matter, there is also a 
need to address whether withdrawal of the FIP and approval of the SIP 
revision will interfere with attainment of the PM NAAQS. There is no 
evidence that withdrawal of the SO2 limits in the FIP and 
the approval of the SO2 emission limits in the SIP revision 
will interfere with attainment of the PM NAAQS. At this time, and 
notwithstanding the fact that the FIP provisions have not gone into 
effect, the areas that would be potentially impacted by the increase in 
SO2 emissions are attaining the 2012 annual PM2.5 
NAAQS. In a Federal Register document signed on January 15, 2015, EPA 
designated all areas in Arkansas as unclassifiable/attainment under the 
2012 annual PM2.5 NAAQS.\84\ All areas in Arkansas were able 
to attain the 2012 annual PM2.5 NAAQS before the 
SO2 and PM emissions limits from the FIP were promulgated.
---------------------------------------------------------------------------

    \84\ 80 FR 2206.
---------------------------------------------------------------------------

    While the FIP provisions might have produced better air quality 
than the provisions we are approving into the SIP, CAA section 110(l) 
does not require that each SIP revision include greater emissions 
reductions than the plan being revised or replaced. Instead, section 
110(l) requires a showing that approval of the SIP revision will not 
interfere with attainment and reasonable further progress or any other 
applicable CAA provision. In this case, the relevant areas are 
attaining the SO2 and PM NAAQS even though the units at 
White Bluff and Independence are emitting SO2 at levels not 
restricted by SIP or FIP limits. Thus, by approving the State's 0.60 
lb/MMBtu SO2 emission limits for White Bluff Units 1 and 2 
and Independence Units 1 and 2, the EPA is approving limits that will 
further reduce emissions from the levels that were already sufficient 
to designate the potentially impacted areas as attainment/
unclassifiable for both the 1-hour SO2 NAAQS and the 2012 
annual PM2.5 NAAQS. Thus, there is no evidence to suggest 
that areas will not continue to attain the NAAQS following our approval 
of the SIP and concurrent withdrawal of the FIP.\85\ Therefore, we find 
that EPA approval of the 0.60 lb/MMBtu SO2 BART emission 
limits for White Bluff Units 1 and 2 and the 0.60 lb/MMBtu 
SO2 emission limits for Independence Units 1 and 2 under the 
long-term strategy will not interfere with attainment of the 2010 1-
hour SO2 NAAQS or the 2012 annual PM2.5 NAAQS 
under CAA section 110(l).
---------------------------------------------------------------------------

    \85\ We also note that for any area where modeling of actual 
SO2 emissions served as the basis for designating such 
area as attainment of the 2010 1-hour SO2 NAAQS, the 
SO2 Data Requirements Rule under 40 CFR 51.1205 requires 
the submission of an annual report that documents the annual 
SO2 emissions of each applicable source in each such area 
and provides an assessment of the cause of any emissions increase 
from the previous year. That report must also include a 
recommendation regarding whether additional modeling is needed to 
characterize air quality in any area to determine whether the area 
continues to meet the 2010 1-hour SO2 NAAQS. Since 
modeling of actual SO2 emissions served as the basis for 
EPA's designation of Jefferson County, where the White Bluff 
facility is located, and redesignation of Independence County, where 
the Independence facility is located, this annual reporting 
requirement applies to ADEQ. The data and other information provided 
by ADEQ in this annual report will help EPA assess whether actual 
annual SO2 emissions from White Bluff, Independence, and 
other sources in Arkansas have increased to such an extent that 
there is uncertainty as to whether the areas where these sources are 
located continue to meet the 2010 1-hour SO2 NAAQS. At 
this time, no reports have been submitted by ADEQ that indicate that 
revised modeling of SO2 emissions from sources in 
Jefferson and Independence Counties is warranted.
---------------------------------------------------------------------------

    Additionally, since there are no areas in Arkansas designated 
nonattainment under the 2010 1-hour SO2 NAAQS or the 2012 
annual PM2.5 NAAQS, the increase in SO2 emissions 
would not impact any such nonattainment areas in the state. We are also 
not aware of any nonattainment areas in downwind states that are likely 
to be impacted by these emissions.
    While the comment appears to focus on SO2 controls for 
the White Bluff and Independence facilities, to the extent that the 
commenter is contending that the SO2 emission limits we are 
taking final action to approve for other facilities would also violate 
the CAA's requirements under section 110(l), we note that this claim is 
incorrect. As explained above, one way of demonstrating noninterference 
is by showing that the status quo air quality will be preserved. In 
this case, the SO2 controls for all other sources in the 
Phase II SIP revision (i.e., AECC Bailey Unit 1, AECC McClellan Unit 1, 
AEP/SWEPCO Flint Creek Plant Boiler No. 1, Entergy Lake Catherine Unit 
4, and the Entergy White Bluff Auxiliary Boiler), which we are taking 
final action to approve, are identical to those contained in the 
Arkansas FIP. All the PM BART controls in the Phase II SIP revision, 
which we are taking final action to approve, are also identical to 
those contained in the Arkansas FIP.
    Comment: EPA's approval of ADEQ's SIP revisions is appropriate even 
though the SIP revision is not based on installation of the same 
control technology that was used to set the limits for White Bluff and 
Independence in the currently stayed FIP. While EPA has interpreted the 
CAA's anti-backsliding provision as allowing the Agency ``to approve a 
SIP revision unless the agency finds it will make the air quality 
worse,'' that standard is inapplicable here where the existing 
requirements have not yet gone into effect and are the subject of 
administrative and judicial challenges. Specifically, the 
SO2 requirements for White Bluff and Independence were 
judicially stayed and cannot be deemed to represent the existing 
limitations applicable to the units. Thus, nothing in the SIP revision 
``weakens or removes any pollution controls.'' To the contrary, the SIP 
revision would impose emission limitations that are better than the 
status quo.
    Response: We agree with the commenter's assertion that, in this 
particular case, our approval of the SIP is appropriate even though the 
SIP revision is not based on installation of the same control 
technology that was used to set the limits for White Bluff and 
Independence in the FIP. However, we disagree with the commenter's 
characterization of the requirements of CAA 110(l) and the commenter's 
characterization of EPA's interpretation of those requirements. Under 
section 110(l) of the CAA, the EPA cannot approve a plan revision if 
the revision would interfere with any applicable requirements 
concerning attainment and reasonable further progress of the NAAQS, or 
any other applicable requirement of the Act. Section 110(l) applies to 
all requirements of the CAA and to all areas of the country regardless 
of their attainment status. To evaluate whether a plan revision would 
interfere with any requirements, air pollutants

[[Page 51048]]

whose emissions and/or ambient concentrations may change as a result of 
the revision must be identified. Noninterference with attainment of the 
NAAQS may be demonstrated by an air quality analysis showing that any 
emission changes associated with the revision will not interfere with 
attainment of the NAAQS. This option requires a showing that the area 
(as well as interstate and intrastate areas downwind) can attain the 
NAAQS even with the plan in its revised form. Noninterference may also 
be demonstrated by showing that the status quo air quality is preserved 
by the use of substitute measures to compensate for any emissions 
increases associated with the revision. See Kentucky Resources Council 
v. EPA, 467 F.3d 986 (6th Cir. 2006). A revision that maintains the 
status quo would not interfere with attainment of the NAAQS. See 
Wildearth Guardians v. EPA, 759 F.3d 1064 (9th Cir. 2014). In general, 
the level of rigor needed for any 110(l) demonstration will vary 
depending on the nature of the revision, its potential impact on air 
quality and the air quality in the affected area.

D. Modeling

    Comment: We received comments arguing that the CALPUFF model is 
unreliable and should not be used in making BART determinations. A 
commenter stated that although CALPUFF may have had some limited 
utility in the BART screening process, it should not be used in making 
an SO2 BART determination for White Bluff due to its 
purported limitations in accuracy and precision given the distances to 
Class I areas and the atmospheric conditions involved, as well as 
limited chemistry mechanism and blanket background ammonia values. One 
commenter presumed that CAMx modeling for White Bluff would likely show 
negligible visibility improvements from each of the SO2 
controls evaluated and contended that SO2 BART is therefore 
the use of low sulfur coal even without Entergy's voluntary decision to 
cease coal combustion at White Bluff. Commenters also argued that 
CALPUFF is no longer an EPA preferred model, and that EPA should 
instead rely on the Comprehensive Air Quality Model with Extensions 
(CAMx), which the commenter claims is more reliable in characterizing 
visibility impairment.
    Response: As we discuss in the Response to Comments (RTC) Document 
associated wih this rulemaking \86\ and the RTC Document associated 
with the Arkansas Regional Haze FIP,\87\ the use of CALPUFF in the 
context of the Regional Haze rule provides results that can be used to 
evaluate the level of visibility benefits anticipated for each level of 
control and is one of several factors considered in the overall BART 
determination. In the rulemaking for the BART Guidelines, we responded 
to comments concerning the limitations and appropriateness of using 
CALPUFF, and we further addressed similar comments in the RTC document 
associated with the Arkansas Regional Haze FIP. We stated in the BART 
Guidelines that the visibility results from CALPUFF could be used as 
one of the five factors in a BART evaluation and the impacts could be 
utilized because CALPUFF was the best modeling method available to 
calculate potential impacts for a BART evaluation.\88\ The regulatory 
status of CALPUFF was changed in the recent revisions to the Guideline 
on Air Quality Models (GAQM) \89\ as far as the classification of 
CALPUFF as a preferred model for transport of pollutants for primary 
impacts, not impacts based on chemistry. The GAQM changes indicated 
that the change in model preferred status had no impact on the use of 
CALPUFF to determine the applicability of BART or the BART 
determination itself.\90\ CALPUFF is an appropriate tool for BART 
evaluations and remains the recommended model for BART.
---------------------------------------------------------------------------

    \86\ See ``Arkansas Regional Haze Phase II SIP Revision Response 
to Comments,'' which can be found in the docket associated with this 
final rulemaking.
    \87\ See ``Response to Comments for the Federal Register Notice 
for the State of Arkansas; Regional Haze and Interstate Visibility 
Transport Federal Implementation Plan,'' dated 8/31/2016. See Docket 
ID. EPA-R06-OAR-2015-0189, Document ID. AR020.0187.
    \88\ 70 FR 39123, 39124. ``We understand the concerns of 
commenters that the chemistry modules of the CALPUFF model are less 
advanced than some of the more recent atmospheric chemistry 
simulations. To date, no other modeling applications with updated 
chemistry have been approved by EPA to estimate single source 
pollutant concentrations from long range transport.'' and in 
discussion of using other models with more advanced chemistry it 
continues, ``A discussion of the use of alternative models is given 
in the Guideline on Air Quality in appendix W, section 3.2.''
    \89\ 82 FR 5182, 5196 (Jan. 17, 2017).
    \90\ 82 FR 5182, 5196 (Jan. 17, 2017). ``As detailed in the 
preamble of the proposed rule, it is important to note that the 
EPA's final action to remove CALPUFF as a preferred appendix A model 
in this Guideline does not affect its use under the FLM's guidance 
regarding AQRV assessments (FLAG 2010) nor any previous use of this 
model as part of regulatory modeling applications required under the 
CAA. Similarly, this final action does not affect the EPA's 
recommendation [See 70 FR 39104, 39122-23 (July 6, 2005)] that 
states use CALPUFF to determine the applicability and level of best 
available retrofit technology in regional haze implementation 
plans.''
---------------------------------------------------------------------------

    The commenter contends that CALPUFF may have had some limited 
utility in the BART screening process (i.e., making ``subject-to-BART'' 
determinations), but that its use for making a BART determination for 
White Bluff is not appropriate. We disagree with this contention. The 
BART Guidelines provide that states should establish a threshold that 
should be no higher than 0.5 deciviews for determining whether sources 
contribute to visibility and are therefore subject to BART \91\ and 
recommend the use of CALPUFF \92\ to predict the visibility impacts 
from a single source at a Class I area to compare against this 
threshold as well as to help inform the BART determination.\93\ The 
CALPUFF modeling ADEQ relied on in its SO2 BART 
determination for White Bluff is consistent with the BART Guidelines 
and Appendix W. Nearly every BART determination made since the 
promulgation of the Regional Haze Rule and the BART Guidelines has 
utilized the CALPUFF modeling method in analyzing impacts. Absent any 
additional information that would justify not using the CALPUFF model 
in this particular case, it is appropriate for the state to rely on 
CALPUFF modeling as it has done to support the White Bluff BART 
determination, consistent with the modeling for nearly every other BART 
determination EPA has reviewed and acted upon. EPA also concluded from 
the evaluation of the Interagency Workgroup on Air Quality Modeling 
(IWAQM) Phase 2 Report case studies that the CALPUFF dispersion model 
performs in a reasonable manner and has no apparent bias toward over or 
under prediction, so long as the transport distance is limited to less 
than 300 km.94 95 We note that since the BART Guidelines 
were finalized in 2005

[[Page 51049]]

there has been more modeling with CALPUFF for BART and PSD primary 
impact purposes and the general community has utilized CALPUFF in the 
300-450 km range many times. EPA has indicated historically that use of 
CALPUFF was generally acceptable at 300 km and for larger emissions 
sources with elevated stacks EPA and FLM representatives have also 
allowed or supported the use of CALPUFF results beyond 400 km in some 
cases.\96\ EPA and FLM representatives have weighed the additional 
potential uncertainties with the magnitude of the modeled impacts in 
comparison to screening/impact thresholds on a case-by-case basis in 
approving the use of CALPUFF results at these extended ranges. 
Furthermore, we note that White Bluff is located within 200 km of Caney 
Creek and Upper Buffalo. Therefore, we find that ADEQ appropriately 
considered CALPUFF modeling for White Bluff in the SIP revision. We 
invite the reader to examine our detailed responses to comments arguing 
against the use of CALPUFF modeling in making BART determinations in 
the RTC Document associated wih this rulemaking \97\ as well as the RTC 
Document associated with the Arkansas Regional Haze FIP.\98\ We find 
that Arkansas' reliance on CALPUFF modeling in the SIP revision is 
reasonable and appropriate since it meets the requirements of the CAA 
and the Regional Haze Rule and is consistent with the BART Guidelines 
and Appendix W. Therefore, we find no reason to disapprove the SIP's 
reliance on CALPUFF modeling.
---------------------------------------------------------------------------

    \91\ 40 CFR 51 Appendix Y, III(A)(1): ``As a general matter, any 
threshold that you use for determining whether a source 
``contributes'' to visibility impairment should not be higher than 
0.5 deciviews.''
    \92\ 40 CFR 51 Appendix Y, III(A)(3): ``CALPUFF is the best 
regulatory modeling application currently available for predicting a 
single source's contribution to visibility impairment''.
    \93\ 70 FR 39123: ``. . . we also recommend that the States use 
CALPUFF as a screening application in estimating the degree of 
visibility improvement that may reasonably be expected from 
controlling a single source in order to inform the BART 
determination.''
    \94\ Interagency Workgroup on Air Quality Modeling (IWAQM) Phase 
2 Summary Report and Recommendations for Modeling Long-Range 
Transport Impacts. Publication No. EPA-454/R-98-019. Office of Air 
Quality Planning & Standards, Research Triangle Park, NC. 1998.
    \95\ See also 68 FR 18458, 2003 Revisions to Appendix W, 
Guideline on Air Quality Models.
    \96\ For example, South Dakota used CALPUFF for Big Stone's BART 
determination, including its impact on multiple Class I areas 
further than 400 km away, including Isle Royale, which is more than 
600 km away. See 76 FR 76656. Nebraska relied on CALPUFF modeling to 
evaluate whether numerous power plants were subject to BART where 
the ``Class I areas [were] located at distances of 300 to 600 
kilometers or more from'' the sources. See Best Available Retrofit 
Technology Dispersion Modeling Protocol for Selected Nebraska 
Utilities, p. 3. EPA Docket ID No. EPA-R07-OAR-2012-0158-0008. Texas 
relied on CALPUFF to screen BART-eligible non-EGU sources at 
distances of 400 to 614 km for some sources. See 79 FR 74818 (Dec. 
16, 2014), 81 FR 296 (Jan. 5, 2016).
    \97\ See ``Arkansas Regional Haze Phase II SIP Revision Response 
to Comments,'' which can be found in the docket associated with this 
final rulemaking.
    \98\ See ``Response to Comments for the Federal Register Notice 
for the State of Arkansas; Regional Haze and Interstate Visibility 
Transport Federal Implementation Plan,'' dated 8/31/2016. See Docket 
ID. EPA-R06-OAR-2015-0189, Document ID. AR020.0187.
---------------------------------------------------------------------------

    With regard to the comment that CAMx modeling would show that 
visibility improvements from each of the SO2 controls 
evaluated are negligible and that SO2 BART should therefore 
be the use of low sulfur coal even without Entergy's voluntary decision 
to cease coal combustion at White Bluff, we emphasize that the issue of 
what would constitute BART in the absence of Entergy's enforceable 
measure to cease burning coal in 2028 is not before the agency in this 
action. We also note that the CALPUFF results are not an apples to 
apples comparison to the CAMx model results referred to by the 
commenter due to differences in metrics, models and model inputs.\99\ 
We discuss this issue and our assessment of CAMx modeling in detail in 
the RTC Document associated with this rulemaking.\100\ In sum, the 
visibility modeling provided in the SIP revision demonstrates that 
scrubber controls are anticipated to result in significant visibility 
benefits.
---------------------------------------------------------------------------

    \99\ Some of the major differences are: (1) CALPUFF modeling 
used maximum 24-hour emission rates, while the CAMx modeling used 
annual average emission rates; (2) CALPUFF focuses on the day with 
the 98th percentile highest visibility impact from the source being 
evaluated, whereas the CAMx modeling analysis was focused 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.
    \100\ See ``Arkansas Regional Haze Phase II SIP Revision 
Response to Comments,'' which can be found in the docket associated 
with this final rulemaking.
---------------------------------------------------------------------------

E. Legal

    Comment: EPA cannot approve Arkansas's SIP submission because ADEQ 
failed to comply with Arkansas's statutory legislative review process 
for rulemaking by not submitting the Regional Haze SIP for legislative 
review; the SIP is therefore invalid and unenforceable until ADEQ 
complies with the law.
    Response: It is EPA's position that Arkansas' SIP revision has met 
applicable requirements for an enforceable SIP, including enforceable 
emission limitations and other control measures, means, or techniques 
as well as schedules and timetables for compliance as required under 
section 110(a)(2)(A). The SIP also includes a program to provide for 
enforcement of the measures described above, as required by section 
110(a)(2)(C). Furthermore, the ADEQ has shown the SIP meets Section 
110(a)(2)(F)(i) through (iii) (monitoring and recordkeeping for 
sources) and section 110(a)(2)(K) (modeling). Section 169A(b)(2) 
requires a regional haze SIP to contain such emission limits, schedules 
of compliance and other measures as may be necessary to make reasonable 
progress, including a long-term strategy and certain defined major 
stationary sources to meet BART. ADEQ's SIP revision included 
Administrative Orders entered between ADEQ and the companies that own 
the facilities that are required to comply with emission limits and 
schedules in compliance with the BART and long-term strategy 
requirements. Based upon all of the above, it is appropriate for EPA to 
approve Arkansas SIP revision in accordance with section 110(k)(3).
    As part of the state's notice and comment period for the SIP, ADEQ 
received a comment that ADEQ lacked the authority to implement the SIP 
revision under state law since the SIP (including the Administrative 
Orders) did not undergo legislative review. The comment further alleged 
that EPA cannot approve the SIP until the Arkansas legislature has 
reviewed the SIP revision. ADEQ responded that the SIP did not need to 
undergo legislative review per Arkansas state law because, among other 
things, it does not fit within the state's statutory definition of a 
``rule'', rather state law defines SIPs as a plan, the statutory 
construction of provisions pertaining to plans, and in particular SIPs, 
exhibits an intent on the part of the Arkansas legislature to create a 
separate and distinct set of requirements for SIPs, and the SIP is 
issued by the Director and such action is subject to an appeals process 
differently from that of a rule. Furthermore, ADEQ has the authority 
under state law to enter into Administrative Orders to include as part 
of its SIP revision. These all establish that legislative review is not 
required for this SIP revision, thereby the state's SIP process met the 
state's statutory requirements and when the Director issued the SIP, it 
became an enforceable document under state law. See Response 33 of 
Arkansas' ``Responsive Summary for State Implementation Plan Revision: 
Revisions to Arkansas SIP: Regional Haze SIP Revision for 2008-2018 
Planning Period.'' \101\ This is a matter of Arkansas interpreting its 
state law. EPA finds it is a reasonable interpretation and defers to 
ADEQ's interpretation regarding the resulting requirements for the 
process for state rulemaking for enforceable SIP revisions.
---------------------------------------------------------------------------

    \101\ https://www.adeq.state.ar.us/air/planning/sip/pdfs/regional-haze/public-notice-and-comments-aggregated.pdf.
---------------------------------------------------------------------------

    Based on ADEQ's response to comments explaining the state authority 
to issue an enforceable SIP revision without the need to undergo state 
legislative review, we find it reasonable

[[Page 51050]]

for the state to conclude that ADEQ followed state law in developing 
and finalizing its SIP revision. Thus, the state's SIP revision is 
enforceable as a matter of state law and ADEQ has met the requirements 
of section 110(a)(2)(A), 110(a)(2)(C), and 110(a)(2)(E) since its SIP 
includes ``necessary assurances'' that the state agency responsible for 
implementing the SIP has adequate ``authority'' under state law ``to 
carry out such implementation plan'' and ``responsibility for ensuring 
adequate implementation'' of the plan. It also includes ``enforceable 
limitations and other control measures'' as necessary to meet ``the 
applicable requirements of the CAA and includes ``a program for 
enforcement'' of the required emission limitations and control 
measures. Thus, it is appropriate for EPA to finalize approval of 
ADEQ's plan since it meets all applicable requirements of the Clean Air 
Act. We believe it is reasonable to rely on ADEQ's explanation and 
interpretation. Moreover, an Administrative Law Judge and the APCEC 
have also upheld the state's interpretation of the state law with 
regards to the issuance of SIPs not being a ``rule'' including SIPs 
containing administrative orders and there being no statutory 
requirement for them to undergo state legislative review. However, we 
also acknowledge that an appeal process of the state rulemaking 
procedures for the SIP revision is still ongoing. When a rulemaking is 
being challenged, the EPA relies on the current legal interpretation of 
state law. If circumstances change where Arkansas is no longer found to 
have followed the state process for issuing the SIP and the 
Administrative Orders and needs to undergo another round of state 
rulemaking because the SIP revision is unenforceable, section 110(k)(5) 
of the CAA allows for EPA to call for plan revisions and sets out 
timetables for a SIP or FIP revision. This is commonly known as a ``SIP 
call.''
    Comment: In its attempt to avoid Arkansas' statutory legislative-
review requirement, ADEQ has repeatedly represented to an Arkansas 
tribunal that the SIP itself is not actually enforceable. Thus, 
according to ADEQ, the SIP itself is not enforceable under state law, 
but only enforceable through separate Administrative Orders. Because 
ADEQ admits that the SIP revision is not, by itself, enforceable, the 
SIP is not approvable under the Clean Air Act. 42 U.S.C. 7410(a)(2)(A). 
EPA cannot approve the SIP revision unless ADEQ corrects the state law 
deficiencies or provides the necessary assurances that the state plan 
is, in fact, an enforceable implementation plan.
    Response: While we agree with the commenter's statement that a 
state must demonstrate that it has the necessary legal authority under 
state law to adopt and implement an enforceable SIP, we disagree with 
the commenter's assertion that Arkansas has failed to demonstrate that 
it has such authority. According to appendix V to 40 CFR part 51, 
states are required to submit evidence that they have this authority at 
the time they submit a SIP revision. Arkansas submitted such evidence. 
See AR020.0267-003 State Legal Authority to Adopt and Implement SIP. 
The requirements that need to be met in order for a state to adopt and 
implement provisions intended to meet CAA requirements vary from state 
to state and are governed by state law. The requirements that govern 
SIP submissions for Arkansas are found in Ark. Code Ann. 8-4-317, and, 
as explained by the State, there is no legislative review required for 
a SIP. See pg. 5 of Ex. A. This position does not make the SIP 
unenforceable. The Director issues the decision and an appeal is 
processed as a permit appeal. ADEQ is not arguing that the SIP is not 
an enforceable decision; rather, it is arguing issuance of the SIP does 
not fall within the state statutory definition of a ``rule'' requiring 
legislative review. As explained above, the State has already provided 
evidence that EPA deemed adequate to meet the requirements in Appendix 
V. We are aware that the commenter requested an adjudicatory hearing at 
the state level, as is appropriate, and the administrative law judge 
ruled in the State's favor. If it is eventually found by a judge or 
hearing officer during the appropriate state judicial or administrative 
process that the Commenter is correct in their assertion that the State 
did not submit an enforceable SIP to EPA, EPA can issue a SIP call 
under CAA 110(k)(5) to require the State to correct this deficiency.
    In addition, the commenter states that ADEQ's position is that the 
SIP revision as a package is not enforceable, only the individual, 
component Administrative Orders. According to the commenter, since the 
SIP package as a whole is not enforceable, it does not meet the 
requirements of CAA section 110(a)(2). We reject that the ADEQ's 
position is that the SIP package as a whole is not enforceable, as 
discussed previously. As explained above, an Administrative Law Judge 
and the Commission have determined that the issuance of the SIP 
revision by the Director did not need legislative review in order for 
the SIP to be adopted and implemented as a matter of state law, thereby 
making it enforceable.

F. General

    Comment: Although public utility plant owners and operators will be 
responsible initially for installing the pollution controls or taking 
other actions required under the Arkansas Regional Haze SO2 
and PM SIP Revision, under Arkansas law, such owners and operators are 
permitted to directly pass through and recover the costs and expenses 
of installing, operating, and maintaining pollution controls from 
electric utility customers and ratepayers through electricity rates and 
tariffs filed with the APSC. In addition, utility plant owners and 
operators are permitted to recover from electric utility customers and 
ratepayers the cost of replacement power or capacity needed to replace 
the premature retirement of electric generating units, or the costs of 
switching fuel at such facilities. These ratepayers, some of which are 
providers of goods and services, would be harmed financially if any of 
these plants were to curtail or modify operations or prematurely close 
pursuant to the Arkansas Regional Haze SO2 and PM SIP 
Revision.
    Response: We appreciate the commenter's concerns. We note that the 
SIP revision submitted by ADEQ did not contain an analysis of the 
impact the requirement of these controls would have on electricity 
ratepayers. Neither has the commenter provided such an analysis. There 
are many factors that could serve to increase or decrease electric 
rates and absent such an analysis, it is not possible to say what 
overall effect the SIP's requirements will have on electric rates. 
ADEQ, in its drafting of the SIP revision, ensured that the 
requirements of the CAA and the Regional Haze Rule were met, including 
cost considerations for BART determinations for each of the affected 
facilities. While we assure the commenter that we are very sensitive to 
the ramifications of our actions in the regional haze program, we note 
that we are approving a majority of the Arkansas Regional Haze 
SO2 and PM SIP Revision as it meets the requirements of the 
CAA and the Regional Haze Rule. Our proposal and our final action 
associated with this document explain the rationale for our approval. 
We cannot disapprove a SIP revision and/or substitute our judgment for 
that of the state when we find that the SIP revision meets all 
requirements of the CAA and applicable federal regulations.

[[Page 51051]]

    Comment: Various commenters expressed support for one or more 
portions of our proposal, including our proposed approval of ADEQ's 
SO2 BART determination for White Bluff Units 1 and 2; 
SO2 BART determination for Flint Creek No. 1 Boiler; 
SO2, NOX, and PM BART determinations for the 
White Bluff Auxiliary Boiler; and ADEQ's reasonable progress 
determination.
    Response: We appreciate support of our proposed approval of ADEQ's 
SIP revision. After careful consideration of all the comments we 
received, we are finalizing our approval of the majority of the SIP 
revision without changes from proposal. We identify the portions of the 
SIP revision we are approving elsewhere in this final action.

IV. Final Action

    We are approving a portion of the Arkansas SIP revision submitted 
on August 8, 2018, as meeting the regional haze requirements for the 
first implementation period. This action includes the finding that the 
submittal meets the applicable regional haze requirements as set forth 
in sections 169A and 169B of the CAA and 40 CFR 51.300-308. The EPA is 
approving the SIP revision submittal as meeting the following regional 
haze requirements for the first implementation period: The core 
requirements for regional haze SIPs found in 40 CFR 51.308(d), 
including the reasonable progress requirements as well as the long-term 
strategy requirements with respect to all sources other than the Domtar 
Ashdown Mill; the SO2, PM, and particular NOX 
BART requirements for regional haze visibility impairment with respect 
to emissions of visibility impairing pollutants from EGUs in 40 CFR 
51.308(e); the requirement for coordination with state and FLMs in 40 
CFR 51.308(i); and the requirement for coordination and consultation 
with states with Class I areas affected by Arkansas sources in 40 CFR 
51.308(d)(3)(i).
    Specifically, the EPA is finalizing approval of the following 
revisions to the Arkansas Regional Haze SIP submitted to EPA on August 
8, 2018: The SO2 and PM BART requirements for the AECC 
Bailey Plant Unit 1; the SO2 and PM BART requirements for 
the AECC McClellan Plant Unit 1; the SO2 BART requirements 
for Flint Creek Plant Boiler No. 1; the SO2 BART 
requirements for the White Bluff Plant Units 1 and 2; the 
SO2, NOX, and PM BART requirements for the White 
Bluff Auxiliary Boiler; and the prohibition on burning of fuel oil at 
Lake Catherine Unit 4 until SO2 and PM BART determinations 
for the fuel oil firing scenario are approved into the SIP by EPA. We 
are also finalizing our approval of the compliance dates and reporting 
and recordkeeping requirements associated with these BART 
determinations. These BART requirements have been made enforceable by 
the state through Administrative Orders that have been adopted and 
incorporated in the SIP revision. We are finalizing our approval of 
these BART Administrative Orders as part of the SIP. The BART 
requirements and associated Administrative Orders are listed under 
Table 1 below. We are finalizing our withdrawal of our February 12, 
2018,\102\ approval of Arkansas' reliance on participation in the CSAPR 
ozone season NOX trading program to satisfy the 
NOX BART requirement for the White Bluff Auxiliary Boiler 
given that Arkansas erroneously identified the Auxiliary Boiler as 
participating in CSAPR for ozone season NOX. We are taking 
final action to replace our prior approval of Arkansas' determination 
for the White Bluff Auxiliary Boiler with our final approval of the 
source-specific NOX BART emission limit contained in the 
Arkansas Regional Haze Phase II SIP revision. The NOX BART 
requirement has been made enforceable by the state through an 
Administrative Order that has been adopted and incorporated in the SIP 
revision. We are finalizing our approval of the Administrative Order 
that contains the NOX BART requirement as part of the SIP. 
The NOX BART requirement and associated Administrative Order 
is listed under Table 1 below. We are finalizing our approval of ADEQ's 
revised identification of the 6A Boiler at the Georgia-Pacific Crossett 
Mill as BART-eligible and the determination based on additional 
information and technical analysis presented in the SIP revision that 
the Georgia-Pacific Crossett Mill 6A and 9A Boilers are not subject to 
BART.
---------------------------------------------------------------------------

    \102\ 83 FR 5927.
---------------------------------------------------------------------------

    We are also finalizing our determination that the reasonable 
progress requirements under Sec.  51.308(d)(1) have been fully 
addressed for the first implementation period. The Arkansas Regional 
Haze Phase I SIP revision, which we approved on February 12, 2018,\103\ 
addressed the reasonable progress requirements with respect to 
NOX emissions and the SIP revision before us addresses the 
reasonable progress requirements with respect to SO2 and PM 
emissions. Specifically, we are finalizing our approval of the state's 
focused reasonable progress analysis and the reasonable progress 
determination that no additional SO2 controls at 
Independence Units 1 and 2 or any other Arkansas sources are necessary 
under reasonable progress for the first implementation period. We are 
also in agreement with the state's calculation of revised RPGs for 
Arkansas' Class I areas. We are basing our final approval of the 
reasonable progress provisions and agreement with the state's 
calculation of the revised RPGs on the following: The state's 
discussion of the key pollutants and source categories that contribute 
to visibility impairment in Arkansas' Class I areas per the CENRAP's 
source apportionment modeling; the state's identification of a group of 
large SO2 point sources in Arkansas for potential evaluation 
of controls under reasonable progress; the state's rationale for 
narrowing down its list of potential sources to evaluate under the 
reasonable progress requirements; and the state's evaluation and 
reasonable weighing of the four statutory factors along with 
consideration of the visibility benefits of controls for the 
Independence facility.
---------------------------------------------------------------------------

    \103\ 83 FR 5927.
---------------------------------------------------------------------------

    The Arkansas Regional Haze Phase II SIP revision does not address 
BART and associated long-term strategy requirements for the Domtar 
Ashdown Mill Power Boilers No. 1 and 2, and the FIP's BART emission 
limits for the facility continue to remain in place at this time. 
However, ADEQ recently submitted a SIP revision to address the regional 
haze requirements for Domtar Power Boilers No. 1 and No. 2, and we will 
evaluate any conclusions ADEQ has drawn in that submission with respect 
to the need to conduct a reasonable progress analysis for Domtar. As 
long as the BART requirements for Domtar continue to be addressed by 
the measures in the FIP, however, we propose to agree with ADEQ's 
conclusion that nothing further is needed to satisfy the reasonable 
progress requirements for the first implementation period. With respect 
to the RPGs for Arkansas' Class I areas, we will assess the SIP 
revision ADEQ recently submitted addressing Domtar to determine if 
changes are needed based on any differences between the SIP-based 
measures and the measures currently contained in the FIP. We intend to 
take action on the SIP revision addressing Domtar in a future 
rulemaking.
    We are finalizing our approval of the components of the long-term 
strategy under Sec.  51.308(d)(3) addressed by the Arkansas Regional 
Haze Phase II SIP revision, including the BART measures contained in 
the SIP revision and the SO2 emission limit of 0.60 lb/MMBtu 
under the long-term strategy provisions

[[Page 51052]]

for Independence Units 1 and 2 based on the use of low sulfur coal. We 
are also finalizing our approval of the compliance date and reporting 
and recordkeeping requirements associated with the SO2 
emission limit for the Independence facility under the long term 
strategy provisions. These requirements for Independence Units 1 and 2 
have been made enforceable by the state through an Administrative Order 
that has been adopted and incorporated in the SIP revision. We are 
finalizing our approval of this BART Administrative Order as part of 
the SIP. The SO2 emission limit and associated 
Administrative Order for the Independence facility are listed under 
Table 2 below. We are making a final determination that Arkansas' long-
term strategy is approved with respect to sources other than the Domtar 
Ashdown Mill. We are also finalizing our determination that Arkansas 
has appropriately provided an opportunity for consultation to the FLMs 
and to Missouri on the SIP revision, as required under Sec.  
51.308(d)(3)(i) and (i)(2).
    The BART emission limits we are approving as source-specific 
requirements that are part of the SIP are presented in Table 1; the 
SO2 emission limits under the long-term strategy and 
associated Administrative Order we are approving for the Independence 
facility are presented in Table 2; and Arkansas' revised 2018 RPGs are 
presented in Table 3.

                       Table 1--SIP Revision BART Emission Limits and Administrative Orders EPA Is Approving in This Final Action
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                        SIP revision PM BART    SIP revision NOX
      Subject-to-BART source              SIP revision SO2 BART emission limits            emission limits    BART emission limits  Administrative order
--------------------------------------------------------------------------------------------------------------------------------------------------------
AECC Bailey Unit 1...............  0.5% limit on sulfur content of fuel combusted *...  0.5% limit on sulfur  Already SIP-approved  Administrative Order
                                                                                         content of fuel                             LIS No. 18-071.
                                                                                         combusted *.
AECC McClellan Unit 1............  0.5% limit on sulfur content of fuel combusted *...  0.5% limit on sulfur  Already SIP-approved  Administrative Order
                                                                                         content of fuel                             LIS No. 18-071.
                                                                                         combusted *.
AEP Flint Creek Boiler No. 1.....  0.06 lb/MMBtu *....................................  Already SIP-approved  Already SIP-approved  Administrative Order
                                                                                                                                     LIS No. 18-072.
Entergy Lake Catherine Unit 4      Unit is allowed to burn only natural gas *.........  Unit is allowed to    Already SIP-approved  Administrative Order
(fuel oil firing scenario).......                                                        burn only natural                           LIS No. 18-073.
                                                                                         gas *.
Entergy White Bluff Unit 1.......  0.60 lb/MMBtu (Interim emission limit with a 3-year  Already SIP-approved  Already SIP-approved  Administrative Order
                                    compliance date and cessation of coal combustion                                                 LIS No. 18-073.
                                    by end of 2028).
Entergy White Bluff Unit 2.......  0.60 lb/MMBtu (Interim emission limit with a 3-year  Already SIP-approved  Already SIP-approved  Administrative Order
                                    compliance date and cessation of coal combustion                                                 LIS No. 18-073.
                                    by end of 2028).
Entergy White Bluff Auxiliary      105.2 lb/hr *......................................  4.5 lb/hr *.........  32.2 lb/hr *........  Administrative Order
 Boiler.                                                                                                                             LIS No. 18-073.
--------------------------------------------------------------------------------------------------------------------------------------------------------
* This BART emission limit required by the SIP revision is the same as what was required under the Arkansas Regional Haze FIP.


   Table 2--SIP Revision Emission Limits Under Reasonable Progress and
               Administrative Orders Proposed for Approval
------------------------------------------------------------------------
                                  SIP revision
                                  SO2 emission
             Source                limits (lb/     Administrative order
                                     MMBtu)
 
------------------------------------------------------------------------
Entergy Independence Unit 1....            0.60  Administrative Order
                                                  LIS No. 18-073.
Entergy Independence Unit 2....            0.60  Administrative Order
                                                  LIS No. 18-073.
------------------------------------------------------------------------


                  Table 3--Arkansas' Revised 2018 RPGs
------------------------------------------------------------------------
                                                          2018 RPG 20%
                     Class I area                       worst days  (dv)
------------------------------------------------------------------------
Caney Creek..........................................              22.47
Upper Buffalo........................................              22.51
------------------------------------------------------------------------

    Concurrent with our final approval of the Arkansas Regional Haze 
Phase II SIP revision, we are finalizing in a separate rulemaking our 
final action to withdraw those portions of the Arkansas Regional Haze 
FIP at 40 CFR 52.173 that impose SO2 and PM BART emission 
limits for Bailey Unit 1; SO2 and PM BART emission limits 
for McClellan Unit 1; the SO2 BART emission limit for Flint 
Creek Boiler No. 1; the SO2 BART emission limits for White 
Bluff Units 1 and 2; the SO2 and PM BART emission limits for 
the White Bluff Auxiliary Boiler; the prohibition on burning fuel oil 
at Lake Catherine Unit 4; and the SO2 emission limits for 
Independence Units 1 and 2 under the reasonable progress 
provisions.\104\
---------------------------------------------------------------------------

    \104\ Our final action withdrawing part of the Arkansas Regional 
Haze FIP is published elsewhere in this issue of the Federal 
Register.

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

[[Page 51053]]

    We find that an approval of the SIP revision meets the Clean Air 
Act's 110(1) provisions. Approval of the Arkansas Regional Haze 
SO2 and PM SIP revision will not interfere with continued 
attainment of all the NAAQS within the state of Arkansas, nor will it 
interfere with any other applicable requirements of the CAA.

V. Incorporation by Reference

    In this final action, we are including regulatory text that 
includes incorporation by reference. In accordance with the 
requirements of 1 CFR 51.5, we are incorporating by reference revisions 
to the Arkansas source-specific requirements as described in the Final 
Action section above. We have made, and will continue to make, these 
documents generally available electronically through 
www.regulations.gov and in hard copy at the EPA Region 6 office (please 
contact the person listed in FOR FURTHER INFORMATION CONTACT for more 
information). Therefore, these materials have been approved by EPA for 
inclusion in the SIP, have been incorporated by reference by EPA into 
that plan, are fully federally enforceable under sections 110 and 113 
of the CAA as of the effective date of the final rulemaking of EPA's 
approval, and will be incorporated in the next update to the SIP 
compilation.

VI. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable Federal regulations. 42 U.S.C. 7410(k)(3); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, the EPA's role is to approve state 
choices, provided that they meet the criteria of the Clean Air Act. 
Accordingly, this action merely approves state law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
     Is not an Executive Order 13771 (82 FR 9339, February 2, 
2017) regulatory action because SIP approvals are exempted under 
Executive Order 12866;
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, described in the Unfunded Mandates 
Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA; and
     Does not provide EPA with the discretionary authority to 
address, as appropriate, disproportionate human health or environmental 
effects, using practicable and legally permissible methods, under 
Executive Order 12898 (59 FR 7629, February 16, 1994).
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where EPA or an Indian tribe has 
demonstrated that a tribe has jurisdiction. In those areas of Indian 
country, the rule does not have tribal implications and will not impose 
substantial direct costs on tribal governments or preempt tribal law as 
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
    The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the 
Small Business Regulatory Enforcement Fairness Act of 1996, generally 
provides that before a rule may take effect, the agency promulgating 
the rule must submit a rule report, which includes a copy of the rule, 
to each House of the Congress and to the Comptroller General of the 
United States. EPA will submit a report containing this action and 
other required information to the U.S. Senate, the U.S. House of 
Representatives, and the Comptroller General of the United States prior 
to publication of the rule in the Federal Register. A major rule cannot 
take effect until 60 days after it is published in the Federal 
Register. This action is not a ``major rule'' as defined by 5 U.S.C. 
804(2).
    Under section 307(b)(1) of the Clean Air Act, petitions for 
judicial review of this action must be filed in the United States Court 
of Appeals for the appropriate circuit by November 26, 2019. Filing a 
petition for reconsideration by the Administrator of this final rule 
does not affect the finality of this action for the purposes of 
judicial review nor does it extend the time within which a petition for 
judicial review may be filed, and shall not postpone the effectiveness 
of such rule or action. This action may not be challenged later in 
proceedings to enforce its requirements. (See section 307(b)(2).)

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Best available 
retrofit technology, Incorporation by reference, Intergovernmental 
relations, Ozone, Particulate Matter, Regional haze, Reporting and 
recordkeeping requirements, Sulfur Dioxide, Visibility.

    Dated: August 28, 2019.
Kenley McQueen,
Regional Administrator, Region 6.

    Title 40, chapter I, of the Code of Federal Regulations is amended 
as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart E--Arkansas

0
2. In Sec.  52.170:
0
a. The table in paragraph (d), entitled ``EPA-Approved Arkansas Source-
Specific Requirements'' is revised; and
0
b. The third table in paragraph (e), entitled ``EPA-Approved Non-
Regulatory Provisions and Quasi-Regulatory Measures in the Arkansas 
SIP,'' is amended by adding and entry for ``Arkansas Regional Haze 
Phase II SIP Revision'' at the end of the table.
    The revision and addition read as follows:


Sec.  52.170  Identification of plan.

* * * * *

[[Page 51054]]

    (d) * * *

                               EPA-Approved Arkansas Source-Specific Requirements
----------------------------------------------------------------------------------------------------------------
                                                          State
                                   Permit or Order      approval/
         Name of source                  No.            effective       EPA approval date          Comments
                                                          date
----------------------------------------------------------------------------------------------------------------
Arkansas Electric Cooperative    Administrative            8/7/2018  9/27/2019 [[Insert       Unit 1.
 Corporation Carl E. Bailey       Order LIS No. 18-                   Federal Register
 Generating Station.              071.                                citation of the final
                                                                      rule].
Arkansas Electric Cooperative    Administrative            8/7/2018  9/27/2019 [[Insert       Unit 1.
 Corporation John L. McClellan    Order LIS No. 18-                   Federal Register
 Generating Station.              071.                                citation of the final
                                                                      rule].
Southwestern Electric Power      Administrative            8/7/2018  9/27/2019 [[Insert       Unit 1.
 Company Flint Creek Power        Order LIS No..                      Federal Register
 Plant.                          18-072............                   citation of the final
                                                                      rule].
Entergy Arkansas, Inc. Lake      Administrative            8/7/2018  9/27/2019 [[Insert       Unit 4.
 Catherine Plant.                 Order LIS No. 18-                   Federal Register
                                  073.                                citation of the final
                                                                      rule].
Entergy Arkansas, Inc. White     Administrative            8/7/2018  9/27/2019 [[Insert       Units 1, 2, and
 Bluff Plant.                     Order LIS No. 18-                   Federal Register         Auxiliary Boiler.
                                  073.                                citation of the final
                                                                      rule].
Entergy Arkansas, Inc.           Administrative            8/7/2018  [[Insert Date of         Units 1 and 2.
 Independence Plant.              Order LIS No. 18-                   publication of the
                                  073.                                final rule in the
                                                                      Federal Register]
                                                                      [[Insert Federal
                                                                      Register citation of
                                                                      the final rule].
----------------------------------------------------------------------------------------------------------------

    (e) * * *
* * * * *

                                EPA-Approved Non-Regulatory Provisions and Quasi-Regulatory Measures in the Arkansas SIP
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                       Applicable geographic     State submittal/
        Name of SIP provision          or nonattainment area      effective date           EPA approval date                    Explanation
--------------------------------------------------------------------------------------------------------------------------------------------------------
 
                                                                      * * * * * * *
Arkansas Regional Haze Phase II SIP   Statewide.............  August 8, 2018          9/27/2019 [[Insert Federal   Regional Haze SIP revision addressing
 Revision.                                                                             Register citation of the     SO2 and PM BART requirements for
                                                                                       final rule].                 Arkansas EGUs, NOX BART requirement
                                                                                                                    for the White Bluff Auxiliary
                                                                                                                    Boiler, reasonable progress
                                                                                                                    requirements for SO2 and PM for the
                                                                                                                    first implementation period, and the
                                                                                                                    long-term strategy requirements. We
                                                                                                                    are approving a portion of this SIP
                                                                                                                    revision. There are two aspects of
                                                                                                                    this SIP revision we are not taking
                                                                                                                    action on at this time: (1) The
                                                                                                                    interstate visibility transport
                                                                                                                    requirements under section
                                                                                                                    110(a)(2)(D)(i)(II); and (2) the
                                                                                                                    long-term strategy is approved with
                                                                                                                    respect to sources other than the
                                                                                                                    Domtar Ashdown Mill.
--------------------------------------------------------------------------------------------------------------------------------------------------------


0
3. In Sec.  52.173, add paragraph (g) to read as follows:


Sec.  52.173  Visibility protection.

* * * * *
    (g) Regional Haze Phase II SIP Revision. A portion of the Regional 
Haze Phase II SIP Revision submitted on August 8, 2018, is approved as 
follows:
    (1) Identification of the 6A Boiler at the Georgia-Pacific Crossett 
Mill as BART-eligible and the determination based on the additional 
information and technical analysis presented in the SIP revision that 
the Georgia-Pacific Crossett Mill 6A and 9A Boilers are not subject to 
BART. (2) SO2 and PM BART for the AECC Bailey Plant Unit 1; 
SO2 and PM BART for the AECC McClellan Plant Unit 1; 
SO2 BART for the AEP/SWEPCO Flint Creek Plant Boiler No. 1; 
SO2 BART for Entergy White Bluff Units 1 and 2; 
SO2, NOX, and PM BART for the Entergy White Bluff 
Auxiliary Boiler; and the prohibition on burning of fuel oil at Entergy 
Lake Catherine Unit 4 until SO2 and PM BART determinations 
for the fuel oil firing scenario are approved into the SIP by EPA.
    (3) The focused reasonable progress analysis and the reasonable 
progress determination that no additional SO2 and PM 
controls are necessary under the reasonable progress requirements for 
the first implementation period.
    (4) The long-term strategy is approved with respect to sources 
other than the Domtar Ashdown Mill. This includes the BART emission 
limits contained in the SIP revision and the SO2 emission 
limit of 0.60 lb/MMBtu under the long-term strategy provisions for 
Independence Units 1 and 2 based on the use of low sulfur coal.
    (5) Consultation and coordination in the development of the SIP 
revision with the FLMs and with other states with Class I areas 
affected by emissions from Arkansas sources.

[FR Doc. 2019-19497 Filed 9-26-19; 8:45 am]
 BILLING CODE 6560-50-P


