Document ID: EPA-R06-OAR-2015-0189-0257
Agency: epa
Document Type: Rule
Title: AR020.0257 Approval and Promulgation of Implementation Plans; Arkansas; Approval of Regional Haze State Implementation Plan Revision for NOx for Electric Generating Units in Arkansas, Final rule, 14 pages.
Posted Date: 2018-02-12T05:00Z

[Federal Register Volume 83, Number 29 (Monday, February 12, 2018)]
[Rules and Regulations]
[Pages 5927-5940]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2018-02147]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R06-OAR-2015-0189; FRL-9973-30-Region 6]

Approval and Promulgation of Implementation Plans; Arkansas; 
Approval of Regional Haze State Implementation Plan Revision for NOX 
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 
revision to the Arkansas State Implementation Plan (SIP) submitted by 
the State of Arkansas through the Arkansas Department of Environmental 
Quality (ADEQ) that addresses regional haze for the first planning 
period. ADEQ submitted this revision to address certain requirements of 
the Clean Air Act (CAA) and the EPA's regional haze rules for the 
protection of visibility. The EPA is taking final action to approve the 
State's SIP revision, which addresses nitrogen oxide (NOX) 
best available retrofit technology (BART) requirements for the 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 and the Auxiliary Boiler. The SIP 
revision also addresses reasonable progress requirements for 
NOX for the Entergy Independence Plant Units 1 and 2. In 
conjunction with this final approval, we are finalizing in a separate 
rulemaking, which is also being published in this Federal Register, our 
withdrawal of federal implementation plan (FIP) emission limits for 
NOX that would otherwise apply to these nine units.

DATES: This rule is effective on March 14, 2018.

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,

[[Page 5928]]

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, 1445 Ross Avenue, Suite 700, Dallas, Texas 
75202-2733.

FOR FURTHER INFORMATION CONTACT: Dayana Medina, 214-665-7241.

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
    C. CSAPR as an Alternative to Source-Specific NOX 
BART
II. Summary of Final Action
III. Response to Comments
    A. Reliance on CSAPR-Better-Than BART Rule
    B. Reasonable Progress
    C. Clean Air Act Section 110(l)
    D. Legal
    E. General
IV. Final Action
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., sulfur dioxide 
(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, ``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 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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    CAA requirements to address the problem of visibility impairment 
continue to be implemented. 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 51.300-51.309. 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 non-substantive 
revisions to the Arkansas Pollution Control and Ecology Commission 
(APCEC) Regulation 19, Chapter 15; this Chapter identified the BART-
eligible and subject-to-BART sources in Arkansas and established BART 
emission limits for subject-to-BART sources. On September 27, 2011, the 
State submitted supplemental information to address the regional haze

[[Page 5929]]

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.\8\ On September 27, 2016, we published 
a FIP addressing the disapproved portions of the 2008 Arkansas Regional 
Haze SIP (the Arkansas Regional Haze FIP).\9\ Among other things, the 
FIP established NOX emission limits under the BART 
requirements for Bailey Unit 1; McClellan Unit 1; Flint Creek Boiler 
No. 1; Lake Catherine Unit 4; and White Bluff Units 1 and 2 and the 
Auxiliary Boiler. The FIP also established NOX emission 
limits under the reasonable progress requirements for Independence 
Units 1 and 2.
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    \8\ 77 FR 14604.
    \9\ 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.\10\ We 
announced in April 2017 our decision to convene a proceeding to 
reconsider several elements of the FIP, including the appropriate 
compliance dates for the NOX emission limits for Flint Creek 
Unit 1, White Bluff Units 1 and 2, and Independence Units 1 and 2.\11\ 
EPA also published a document in the Federal Register on April 25, 
2017, administratively staying the effectiveness of the 18-month 
NOX compliance dates in the FIP for these units for a period 
of 90 days.\12\ On July 13, 2017, the EPA published a proposed rule to 
extend the NOX compliance dates for Flint Creek Unit 1, 
White Bluff Units 1 and 2, and Independence Units 1 and 2, by 21 months 
to January 27, 2020.\13\ \14\
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    \10\ See the docket associated with this proposed 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).
    \11\ 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.
    \12\ 82 FR 18994.
    \13\ 82 FR 32284.
    \14\ EPA has not taken final action on the July 13, 2017 
proposed rule. This final action approving the Arkansas Regional 
Haze NOX SIP revision together with the separate final 
action that EPA is taking to withdraw the source-specific 
NOX emission limits for the nine EGUs in the Arkansas 
Regional Haze FIP, make it unnecessary to finalize our July 13, 2017 
proposed rule to revise the NOX compliance dates in the 
Arkansas Regional Haze FIP.
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    On July 12, 2017, Arkansas submitted a proposed SIP revision with a 
request for parallel processing, addressing the NOX 
requirements for Bailey Unit 1, McClellan Unit 1, Flint Creek Boiler 
No. 1, Lake Catherine Unit 4, White Bluff Units 1 and 2 and the 
Auxiliary Boiler, and Independence Units 1 and 2 (Arkansas Regional 
Haze NOX SIP revision or Arkansas NOX SIP 
revision). In our March 12, 2012 final action on the 2008 Arkansas 
Regional Haze SIP, we disapproved the State's source-specific 
NOX BART determinations for Bailey Unit 1; McClellan Unit 1; 
Flint Creek Boiler No. 1; Lake Catherine Unit 4; White Bluff Units 1 
and 2 and its auxiliary boiler.\15\ In that same action, we also made 
the determination that the State did not satisfy the statutory and 
regulatory requirements for the reasonable progress analysis. We 
promulgated a FIP on September 27, 2016, that established source-
specific NOX BART emission limits for these seven EGUs and 
NOX emission limits under reasonable progress for 
Independence Units 1 and 2 to address the disapproved portions of the 
2008 Arkansas Regional Haze SIP submittal.
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    \15\ 77 FR 14604.
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    Arkansas' proposed July 2017 Regional Haze NOX SIP 
revision addressed the NOX BART requirements for Arkansas' 
EGUs by relying on participation in the Cross State Air Pollution Rule 
(CSAPR) ozone season NOX trading program as an alternative 
to BART. The July 2017 Regional Haze NOX SIP revision 
proposal also made the determination that no additional NOX 
emission controls for Arkansas sources, beyond participation in CSAPR's 
ozone season NOX trading program, are required for ensuring 
reasonable progress in Arkansas. As noted above, the July 2017 Regional 
Haze SIP revision addresses NOX requirements for the same 
EGUs for which we established source-specific NOX emission 
limits in our September 27, 2016 FIP. In a document published in the 
Federal Register on September 11, 2017, we proposed to approve the 
Arkansas Regional Haze NOX SIP revision.\16\ On October 31, 
2017, we received ADEQ's final NOX SIP revision addressing 
BART and reasonable progress requirements for NOX for EGUs 
in Arkansas for the first implementation period. The final Arkansas 
Regional Haze NOX SIP revision we received on October 31, 
2017, did not contain significant changes from the state's proposed SIP 
revision. Therefore, it is appropriate for us to take final action, as 
proposed, on the final SIP revision.
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    \16\ 82 FR 42627.
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C. CSAPR as an Alternative to Source-Specific NOX BART

    In 2005, the EPA published the Clean Air Interstate Rule (CAIR), 
which required 27 states and the District of Columbia to reduce 
emissions of SO2 and NOX from affected electric 
generating units (EGUs) that significantly contribute to or interfere 
with maintenance of the 1997 national ambient air quality standards 
(NAAQS) for fine particulates and/or 8-hour ozone in any downwind 
state.\17\ EPA demonstrated that CAIR would achieve greater reasonable 
progress toward the national visibility goal than would BART; 
therefore, states could rely on CAIR as an alternative to BART for 
SO2 and NOX at EGUs.\18\ Although Arkansas was 
subject to certain NOX requirements of CAIR, including the 
state-wide ozone season NOX budget but not the annual 
NOX budget, and although this would have been sufficient for 
Arkansas to rely on CAIR to satisfy NOX BART, it elected not 
to rely on CAIR in its 2008 Regional Haze SIP to satisfy the 
NOX BART requirement for its EGUs.
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    \17\ 70 FR 25161 (May 12, 2005).
    \18\ 70 FR 39104, 39139 (July 6, 2005).
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    On July 11, 2008, the D.C. Circuit found CAIR was fatally flawed 
and on December 23, 2008, the Court remanded CAIR to EPA without 
vacatur to ``preserve the environmental benefits provided by CAIR.'' 
\19\ In 2011, acting on the D.C. Circuit's remand, we promulgated the 
Cross-State Air Pollution Rule (CSAPR) to replace CAIR and issued FIPs 
to implement the rule in CSAPR-subject states.\20\ Arkansas EGUs are 
covered under CSAPR for ozone season NOX.\21\
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    \19\ North Carolina v. EPA, 531 F.3d 896, 901 (D.C. Cir. 2008), 
modified, 550 F.3d 1176, 1178 (D.C. Cir. 2008).
    \20\ 76 FR 48207 (August 8, 2011).
    \21\ 76 FR 82219 (December 30, 2011).
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    In 2012, we issued a limited disapproval of several states' 
regional haze SIPs because of reliance on CAIR as an alternative to EGU 
BART for SO2 and/or NOX.\22\ We also determined 
that CSAPR would provide for greater reasonable progress than BART and 
amended the Regional Haze Rule to allow for CSAPR participation as an 
alternative to source-specific SO2 and/or NOX 
BART for EGUs, on a pollutant-specific basis.\23\ As Arkansas did not

[[Page 5930]]

rely on CAIR to satisfy the NOX BART requirements in the 
2008 Regional Haze SIP, Arkansas was not included in the EPA's limited 
disapproval of regional haze SIPs that relied on CAIR to satisfy 
certain regional haze requirements.\24\ As noted above, in the 2012 
rulemaking in which we promulgated those limited disapprovals, the EPA 
also promulgated FIPs to replace reliance on CAIR with reliance on 
CSAPR in many of those regional haze SIPs; however, Arkansas was 
likewise not included in that FIP action.
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    \22\ The limited disapproval triggered the EPA's obligation to 
issue a FIP or approve a SIP revision to correct the relevant 
deficiencies within 2 years of the final limited disapproval action. 
CAA section 110(c)(1); 77 FR 33642, at 33654 (June 7, 2012).
    \23\ See 40 CFR 51.308(e)(4).
    \24\ See 77 FR 33642, at 33654.
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    CSAPR has been subject to extensive litigation, and on July 28, 
2015, the DC Circuit issued a decision generally upholding CSAPR but 
remanding without vacating the CSAPR emissions budgets for a number of 
states.\25\ On October 26, 2016, we finalized an update to CSAPR that 
addresses the 1997 ozone NAAQS portion of the remand as well as the CAA 
requirements addressing interstate transport for the 2008 ozone 
NAAQS.\26\ Additionally, three states, Alabama, Georgia, and South 
Carolina, have adopted or committed to adopt SIPs to continue their 
participation in the CSAPR program, including adoption on a voluntary 
basis of state SO2 emission budgets equal to those state's 
remanded SO2 emission budgets. On November 10, 2016, we 
proposed a rule intended to address the remainder of the court's remand 
as it relates to Texas.\27\ This separate proposed rule included an 
assessment of the impacts of the set of actions that the EPA had taken 
or expected to take in response to the D.C. Circuit's remand on our 
2012 demonstration that participation in CSAPR provides for greater 
reasonable progress than BART. Based on that assessment, the EPA 
proposed that states may continue to rely on CSAPR as an alternative to 
BART on a pollutant-specific basis. On September 29, 2017, we finalized 
our proposed finding that the EPA's 2012 analytical demonstration 
remains valid and that participation in CSAPR, as it now exists, meets 
the Regional Haze Rule's criteria for an alternative to BART.\28\ In 
the October 2017 Arkansas Regional Haze NOX SIP revision, 
the state relies on CSAPR as an alternative to BART for control of 
NOX from EGUs.
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    \25\ Arkansas' ozone season NOX budgets were not 
included in the remand. EME Homer City Generation v. EPA, 795 F.3d 
118, 138 (D.C. Cir. 2015).
    \26\ 81 FR74504 (October 26, 2016).
    \27\ 81 FR 78954 (November 10, 2016).
    \28\ 82 FR 45481 (September 29, 2017).
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II. Summary of Final Action

    This action finalizes our proposed approval of the Arkansas 
Regional Haze NOX SIP revision, which relies on EPA's 
determination that CSAPR provides for greater reasonable progress than 
BART to address the NOX BART requirements for Arkansas EGUs. 
Consistent with 40 CFR 51.308(e)(4), Arkansas makes the determination 
that since the Arkansas EGUs are currently subject to the CSAPR 
requirements for ozone-season NOX, the State need not have 
source specific requirements for subject-to-BART EGUs to install, 
operate, and maintain BART for NOX. We find that it is 
appropriate for Arkansas to rely on participation in the CSAPR ozone 
season NOX trading program to satisfy the NOX 
BART requirements for Arkansas EGUs. EPA's 2012 determination and our 
September 29, 2017 final rulemaking make the finding that the EPA's 
2012 analytical demonstration remains valid and that participation in 
CSAPR, as it now exists, meets the Regional Haze Rule's criteria for an 
alternative to BART.\29\ Arkansas' reliance on CSAPR addresses 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 the Auxiliary Boiler.
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    \29\ 82 FR 45481 (September 29, 2017).
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    We also find that Arkansas reasonably determined that additional 
NOX control measures are not needed to ensure reasonable 
progress for the first implementation period. Given the level of 
visibility impairment due to NOX emissions from Arkansas 
point sources at the state's two Class I areas, Caney Creek and Upper 
Buffalo, on the 20% worst days, additional NOX controls for 
Arkansas point sources are not anticipated to yield meaningful 
visibility improvements at Arkansas Class I areas on the 20% worst 
days.\30\ In light of this, and considering that Arkansas EGUs are 
participating in CSAPR for ozone season NOX, we are 
finalizing our determination that Arkansas' decision to screen out 
Arkansas point sources from further evaluation of additional 
NOX controls is reasonable and we are finalizing our 
approval of Arkansas' determination that no additional NOX 
controls, beyond Arkansas EGU participation in CSAPR for ozone season 
NOX, are necessary to satisfy the reasonable progress 
requirements for NOX in Arkansas for the first 
implementation period.
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    \30\ Arkansas also recognized that sources in Arkansas impact 
the two Class I areas in Missouri: Hercules Glade Wilderness Area 
and Mingo Wilderness Area. Arkansas provided the Missouri Department 
of Natural Resources with an opportunity for consultation on the 
proposed Arkansas NOX SIP revision, including an 
opportunity to discuss Missouri's assessment of the impact of the 
proposed SIP revision on reasonable progress at Missouri Class I 
areas. The Missouri Department of Natural Resources did not have 
comments on the proposed SIP revision and did not pursue 
consultation. Additionally, Arkansas looked at the most recent five-
year rolling average of observed visibility impairment on the 20% 
haziest days for Missouri's Class I areas and concluded that the 
visibility progress observed at the IMPROVE monitors indicates that 
sources in Arkansas are not interfering with the achievement of 
Missouri's 2018 RPGs for Hercules Glades and Mingo. Taking these 
things into consideration, Arkansas made the determination that no 
additional NOX reductions from Arkansas sources are 
required to improve visibility in Missouri Class I areas for the 
first implementation period.
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    We are finalizing our approval of the Arkansas Regional Haze 
NOX SIP revision as we have found it to meet the applicable 
provisions of the Act and EPA regulations and it is consistent with EPA 
guidance. We received comments from three commenters on our proposed 
approval. Our response 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 determination are warranted.
    We are approving the October 2017 Arkansas Regional Haze 
NOX SIP revision submitted by ADEQ as we have determined 
that it meets the regional haze SIP requirements, including the 
reasonable progress requirements in Sec.  51.308(d) and the BART 
requirements in Sec.  51.308(e). In conjunction with this final 
approval, we are finalizing in a separate rulemaking, which is also 
being published in this Federal Register, our withdrawal of FIP 
emission limits for NOX that would otherwise apply to the 
nine affected units.

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. We reviewed all public comments that we received 
on the proposed action. Below, we provide a summary of certain comments 
and our responses. The comments and our responses thereto are contained 
in a separate document titled the Arkansas Regional Haze NOX 
SIP Revision Response to Comments.

A. Reliance on CSAPR-Better-Than-BART Rule

    Comment: ADEQ proposes to rely on ozone-season NOX 
reductions under the updated CSAPR in lieu of the source-specific BART 
emission limits that EPA finalized as part of its 2016 regional

[[Page 5931]]

haze FIP. ADEQ relies on a ``back-of-the-envelope'' calculation of 
anticipated emission reductions, and asserts that EPA's updated 2018 
Arkansas ozone season NOX emission budgets under the CSAPR 
update achieve a greater reduction in NOX emissions than do 
implementation of NOX BART controls included in the Arkansas 
Regional Haze FIP. Without any further analysis, ADEQ suggests that 
compliance with the 2018 CSAPR ozone season allocations for Arkansas 
EGUs satisfies the BART requirements of the Regional Haze Rule.
    Response: This comment is in relation to ADEQ's comparison of 
anticipated NOX emissions reductions based on the CSAPR 
emission budgets versus the anticipated NOX emissions 
reductions from the Arkansas Regional Haze FIP. We did not base our 
proposed approval of the Arkansas NOX SIP revision on the 
state's comparison of the anticipated NOX reductions in 
Arkansas from CSAPR against those anticipated from the FIP. 
Furthermore, in response to comments that the state received during its 
state rulemaking process, ADEQ proceeded to remove from its final SIP 
revision the comparison of anticipated NOX emissions 
reductions under the FIP versus CSAPR because such information is not 
necessary for EPA approval of the SIP.\31\ With regard to the comment 
that ADEQ did not adequately support its determination that compliance 
with the 2018 CSAPR ozone season allocations for Arkansas EGUs 
satisfies the BART requirements, we disagree that ADEQ was required to 
undertake a state-specific analysis of whether reliance on CSAPR 
provides for greater reasonable progress than BART; as allowed under 40 
CFR 51.308(e)(4), Arkansas is relying on EPA's determination that CSAPR 
provides for greater reasonable progress than BART to address the 
NOX BART requirements for its EGUs. Arkansas' EGUs are 
currently subject to the CSAPR requirements for ozone-season 
NOX, the State need not require subject-to-BART EGUs to 
install, operate, and maintain BART for NOX. As explained 
above, although the D.C. Circuit remanded the CSAPR emissions budgets 
of certain states in 2015, we recently reaffirmed our determination 
that participation in CSAPR, as it now exists, continues to meet the 
Regional Haze Rule's criteria for an alternative to BART.\32\
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    \31\ See final Arkansas NOX SIP revision, Tab E 
(Public Comment Period Documentation, Responsive Summary for State 
Implementation Plan Revision, p. 20).
    \32\ 82 FR 45481 (September 29, 2017).
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    Comment: Arkansas' proposal unlawfully exempts sources from 
installing BART controls without going through the exemption process 
Congress prescribed. The visibility protection provisions of the Clean 
Air Act include a ``requirement'' that certain sources ``install, and 
operate'' BART controls. Congress specified the standard by which 
sources could be exempted from the BART requirements, which is that the 
source is not ``reasonably anticipated to cause or contribute to a 
significant impairment of visibility'' in any Class I area. Appropriate 
federal land managers must concur with any proposed exemption. Neither 
EPA nor Arkansas has demonstrated that the Arkansas EGUs subject to 
BART meet the standards for an exemption. Nor has EPA or the state 
obtained the concurrence of federal land managers. Therefore, Arkansas 
must require source-specific BART for each power plant subject to BART.
    Response: To the extent the comment is directed to prior final 
agency actions allowing states to rely on alternatives to BART 
generally or on CSAPR specifically to meet the BART requirements, this 
comment falls outside of the scope of our action here. Objections that 
the use of BART alternatives does not comply with 42 U.S.C. 
7491(b)(2)(A) do not properly pertain to this action, but instead to 
our past regulatory actions that provided for BART alternatives.\33\ We 
do note that the Arkansas SIP does not exempt the EGUs from BART but 
rather relies on EPA's determination that states may rely on CSAPR as 
an alternative means of meeting the BART requirements.
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    \33\ See the June 7, 2012 final rulemaking where we made the 
determination that CSAPR provides for greater reasonable progress 
than BART (77 FR 33642). See also our September 29, 2017 final 
rulemaking where we made the finding that the EPA's 2012 analytical 
demonstration remains valid and that participation in CSAPR, as it 
now exists, meets the Regional Haze Rule's criteria for an 
alternative to BART (82 FR 45481).
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    Comment: Even if Arkansas could meet a BART statutory exemption 
test, the state cannot rely on CSAPR because of flaws in the rule that 
purport to show that CSAPR makes more reasonable progress than BART 
(the ``Better than BART'' rule). EPA's regulations purport to allow the 
use of an alternative program in lieu of source-specific BART only if 
the alternative makes ``greater reasonable progress'' than would BART. 
To demonstrate greater reasonable progress, a state or EPA must show 
that the alternative program does not cause visibility to decline in 
any Class I area and results in an overall improvement in visibility 
relative to BART at all affected Class I areas. Here, EPA claims that 
its 2012 ``Better than BART'' rule demonstrated that CSAPR achieves 
greater reasonable progress than BART.
    EPA compared CSAPR to BART in the Better than BART rule by using 
CSAPR allocations that are more stringent than now required as well as 
by using presumptive BART limits that are less stringent than required 
under the statute. These assumptions tilted the scales in favor of 
CSAPR. It would be arbitrary and capricious for EPA to rely on such an 
inaccurate, faulty comparison to conclude that CSAPR will achieve 
greater reasonable progress than will BART. Even under EPA's skewed 
comparison, CSAPR achieves barely more visibility improvement than BART 
at the Breton and Caney Creek National Wilderness Areas. If EPA had 
modeled accurate BART limits and up-to-date CSAPR allocations, then EPA 
would likely find that CSAPR would lead to less visibility improvement 
than BART.
    EPA cannot lawfully rely on the Better than BART rule because the 
rule is based on a version of CSAPR that no longer exists. Accordingly, 
any conclusion that EPA made in the 2012 Better than BART rule 
regarding whether CSAPR achieves greater reasonable progress than BART 
is no longer valid. Since 2012, EPA has significantly changed the 
allocations and the compliance deadlines for CSAPR. Of particular 
relevance here, after 2012, EPA increased the total ozone season CSAPR 
allocations for every covered EGU in Arkansas. EPA also extended the 
compliance deadlines by three years, such that the phase 1 emissions 
budgets take effect in 2015-2016 and the phase 2 emissions budgets take 
effect in 2017 and beyond.
    In addition to EPA's increased emissions budgets and extended 
compliance timeline, the D.C. Circuit's decision in EME Homer City 
Generation v. EPA, 795 F.3d 118, 130-32 (D.C. Cir. 2015), which 
invalidated the SO2 or NOX emission budgets for 
thirteen states, has fundamentally undermined the rationale underlying 
EPA's Better than BART rule. Specifically, the Court invalidated the 
2014 SO2 emission budgets for Alabama, Georgia, South 
Carolina, and Texas, and the 2014 NOX emission budgets for 
Florida, Maryland, New Jersey, New York, North Carolina, Ohio, 
Pennsylvania, South Carolina, Texas, Virginia, and West Virginia. As 
explained in our initial brief in the still-pending challenge to the 
CSAPR Better than BART rule, the effect of Homer City is to pull the 
rug out from under EPA's BART exemption rule. EPA's finding that CSAPR 
would produce better

[[Page 5932]]

visibility improvement than BART was premised on the existence of all 
the state-specific emission budgets adopted in the Transport Rule. 
Because the D.C. Circuit has now invalidated many of those budgets, the 
BART exemption rule is left without the factual basis on which it 
relied.
    Response: As we had proposed, our finalized determination that 
CSAPR participation will resolve the NOX BART requirements 
for Arkansas EGUs is based on a separately proposed and recently 
finalized action that affirms that participation in CSAPR, as it now 
exists, continues to meet the Regional Haze Rule's criteria for an 
alternative to BART.\34\ This comment is directed to the separately 
proposed action that was finalized on September 29, 2017, and 
therefore, falls outside of the scope of our action here.
---------------------------------------------------------------------------

    \34\ 82 FR 45481 (September 29, 2017).
---------------------------------------------------------------------------

    Comment: Arkansas's reliance on CSAPR as an alternative to BART is 
unlawful because the emissions reductions achieved by CSAPR in Arkansas 
are limited to five months of the year--the ozone season. Under the 
Regional Haze Rule, BART represents a year-round limit on emissions. 
Given that CSAPR does not limit annual NOX emissions from 
Arkansas sources, but instead only applies to Arkansas sources for five 
months out of the year, CSAPR cannot satisfy the Regional Haze Rule's 
requirement that sources meet the ``best system of continuous emission 
reduction'' for NOX. In fact, as noted in EPA's Technical 
Support Document for the proposed disapproval of Arkansas's 2008 SIP, 
the adverse impacts of Arkansas NOX emissions on visibility 
``tend to be a large component of visibility impairment during the 
winter months''--i.e., outside of the ozone season. Thus, 
NOX emissions reductions that are effective only during the 
ozone season will not address the visibility impact due to wintertime 
ammonium nitrate at Breton Island or other Class I areas in neighboring 
states.
    Even within the five-month ozone season, CSAPR allows for temporal 
variability such that a facility could emit at high levels within a 
shorter time period, creating higher than anticipated visibility 
impacts. Because of the high degree of variability and flexibility, 
power plants may exercise options that would lead to little or no 
emission reductions. For example, a facility in Arkansas might purchase 
emission credits from a source beyond the air shed of the Class I area 
the Arkansas source impairs. Because CSAPR requirements only pertain to 
the Arkansas source for a fraction of the year, that source may be even 
more incentivized to purchase emission credits from elsewhere than a 
source in a fully covered CSAPR state. Thus, without knowing which 
Arkansas EGUs will reduce pollutants by what amounts under CSAPR, or 
when they will do so, and because these emissions reductions are 
applicable for less than half the year, Arkansas simply cannot know the 
impact of CSAPR upon Breton and other affected Class I areas.
    For these reasons, reliance on CSAPR to satisfy the NOX 
BART requirements is unlawful. EPA should disapprove Arkansas' reliance 
on CSAPR to satisfy the NOX requirements.
    Response: These comments fall outside the scope of this rulemaking. 
In 2012, when we finalized our determination that CSAPR provides for 
greater reasonable progress than BART, we considered comments that the 
imposition of BART would require year-round operation of NOX 
controls but that under CSAPR there would be no assurance that controls 
would operate outside of the ozone season. The basis for our decision 
to allow Arkansas and other states covered by CSAPR for ozone season 
only to rely on participation in that program to satisfy NOX 
BART is explained in that rulemaking.\35\
---------------------------------------------------------------------------

    \35\ 77 FR at 33650.
---------------------------------------------------------------------------

    Comment: Arkansas purports to satisfy the regulatory requirements 
for a BART alternative by relying on ozone-season budgets for 
NOX that no longer exist. To rely on CSAPR as an alternative 
to BART, Arkansas must demonstrate that the version of CSAPR that is 
now in effect, and will be in effect at the time of the final rule, 
makes greater reasonable progress than BART. Having failed to make that 
demonstration, Arkansas has not met its burden to show that CSAPR will 
achieve greater reasonable progress than source-specific BART. More 
troubling, Arkansas' reliance on the CSAPR ``Better than BART'' rule 
fails to account for, or even mention, the possibility that CSAPR or 
the ``Better than BART'' rule will not exist in any form when the SIP 
is finalized.
    Response: As we had proposed, our finalized determination that 
CSAPR participation will resolve NOX BART requirements for 
Arkansas EGUs is based on a separately proposed and finalized action 
taken in 2012. On September 29, 2017, we affirmed our proposed finding 
that the EPA's 2012 analytical demonstration remains valid and that 
participation in CSAPR, as it now exists, meets the Regional Haze 
Rule's criteria for an alternative to BART.\36\ This comment falls 
outside of the scope of our action here.
---------------------------------------------------------------------------

    \36\ 82 FR 45481 (September 29, 2017).
---------------------------------------------------------------------------

    Comment: When evaluating a state's BART determination, the EPA 
looks at existing requirements and cannot rely on potential future 
actions in its decision to approve or disapprove a state SIP. As EPA 
recognizes in the proposed approval, the agency cannot finalize 
Arkansas' proposed SIP until EPA finalizes its finding that CSAPR 
continues to be better than BART as an alternative to source-specific 
EGU BART for NOX. Although EPA, on September 29, 2017, 
finalized a rule purporting to conclude that ozone-season 
NOX limitations under CSAPR continue to be ``better than 
BART'' for eligible EGUs in Arkansas, EPA failed to include any of the 
documentation or analyses supporting that finding in this docket. As 
such, EPA cannot approve Arkansas's SIP proposal unless and until those 
analyses are included in the docket and the public has a meaningful 
opportunity to comment on those materials.
    Response: We included the notice of proposed rulemaking addressing 
whether CSAPR continues to be better than BART following changes to the 
budgets of certain states in our docket for this action because of its 
relevance to Arkansas' proposed SIP revision.\37\ As explained in our 
proposed approval of Arkansas' SIP revision, EPA would be able to 
approve regional haze SIP submissions that rely on participation in 
CSAPR as an alternative to BART only if it were to finalize its 
proposed rule or to otherwise determine that participation in CSPAR 
remains a viable BART alternative.\38\ We accordingly made clear that a 
final determination that CSAPR participation will resolve the 
NOX BART requirements for Arkansas' EGUs is based on a 
separately proposed and finalized action. The supporting materials and 
analyses underlying that action are contained in the docket for that 
action, and the public has had a meaningful opportunity to comment on 
that determination.
---------------------------------------------------------------------------

    \37\ See the document in the docket titled ``AR020.0250 CSAPR 
Better than BART Proposed Rulemaking, dated November 10, 2016.''
    \38\ 82 FR at 42629.
---------------------------------------------------------------------------

    Comment: EPA should approve the Arkansas Regional Haze 
NOX SIP revision because it satisfies the criteria of the 
Regional Haze program. The states, not EPA, play the lead role in 
designing and implementing [the] regional haze programs. EPA may 
disapprove a SIP only if it does not satisfy the minimum criteria of 
Section

[[Page 5933]]

110 of the Clean Air Act. Accordingly, EPA has no authority to question 
the wisdom of a State's choices of emission limitations if they are 
part of a plan which satisfies the standards of Section 110(a)(2), and 
has no authority to disapprove of a SIP ``simply on a preference for a 
particular control measure. The SIP revision meets the requirements of 
the Regional Haze Program and must be approved. ADEQ's determination 
that compliance with the CSAPR ozone season NOX trading 
program requirements satisfies NOX BART and any reasonable 
progress obligations for the state's EGUs is consistent with the 
Regional Haze Rule, is appropriate considering the minimal role that 
NOX emissions play in visibility impairment in Arkansas' 
Class I areas, and would eliminate the unnecessary and duplicative 
requirements currently imposed by the Arkansas Regional Haze FIP.
    Response: We appreciate the commenter's support of our proposed 
approval of the Arkansas Regional Haze NOX SIP revision. As 
we had proposed, we are finalizing our approval of the Arkansas 
Regional Haze NOX SIP revision.

B. Reasonable Progress

    Comment: The State attempts to justify the elimination of 
reasonable progress controls on Independence by claiming that the CSAPR 
allocations for NOX will result in greater reductions in 
NOX emissions than the FIP would. The State's rationale has 
no basis in law or in fact. To begin, there is no statutory or 
regulatory provision which allows states to rely on CSAPR in lieu of 
conducting a four-factor analysis of reasonable progress. While EPA has 
issued a rule that purports to allow states to rely on CSAPR in lieu of 
imposing source-specific controls on BART sources, EPA has not issued a 
comparable rule for reasonable progress.
    Moreover, the State's comparison of NOX reductions under 
CSAPR versus the FIP is flawed. The State compares CSAPR allocations to 
binding reductions which must occur under the FIP, based on legally 
enforceable emissions limits. This compares apples to oranges. As the 
name suggest, CSAPR allocations are not emissions limits, they are 
initial entitlements to emit certain amounts of pollution. Sources can 
emit more than their initial allocations, because CSAPR allows both 
intra- and inter-state trading of allowances. Thus, it is highly 
misleading to treat CSAPR allocations as binding emission limits which 
can be compared directly to the emission limits and reductions under 
the Arkansas Regional Haze FIP.
    ADEQ further claims in its SIP that it ``anticipates that some EGUs 
will choose to install combustion controls to comply with CSAPR that 
would reduce emissions year-round, not just in the ozone season.'' ADEQ 
provides no evidence for this assumption. More importantly, ADEQ 
wrongly conflates installation of controls with operation and optimized 
operation of controls. Even if it were true that some EGUs will install 
controls to comply with CSAPR, ADEQ provides no reason to assume that 
EGUs will operate those controls when they are not legally required to 
do so. ADEQ has advanced no basis for assuming that Arkansas EGUs will 
spend additional money to run NOX controls or optimize them 
to reduce NOX when they are not required to do so, i.e., 
outside of the CSAPR ozone season. Thus, there is no record basis for 
assuming that CSAPR will reduce NOX emissions in Arkansas 
outside of the ozone season.
    Response: We disagree with the commenter that Arkansas is relying 
on CSAPR in lieu of conducting an appropriate reasonable progress 
analysis. In assessing the need for additional NOX controls 
to address reasonable progress, Arkansas focused its reasonable 
progress assessment on the Central Regional Air Planning (CENRAP) \39\ 
Comprehensive Air Quality Model with extensions (CAMx) source 
apportionment modeling,\40\ and observed that a small portion of total 
light extinction is due to nitrate (NO3) from Arkansas 
sources and that this portion is driven by on-road sources and not 
point sources. Arkansas notes that the source apportionment data show 
that NO3 from Arkansas point sources contributes less than 
0.5% of the total light extinction at Caney Creek and Upper Buffalo on 
the 20% worst days in 2002, and that, for the first implementation 
period, NOX is not a key pollutant contributing to 
visibility impairment at Arkansas' Class I areas on those days. Based 
on the above observations, Arkansas reached the conclusion that, for 
the first implementation period, additional NOX controls for 
Arkansas point sources are not anticipated to yield meaningful 
visibility improvements at Arkansas Class I areas on the 20% worst days 
in view of the amount of visibility impairment attributed to these 
sources. Given the level of visibility impairment due to NOX 
from Arkansas point sources at Caney Creek and Upper Buffalo on the 20% 
worst days and considering that Arkansas EGUs are participating in 
CSAPR for ozone season NOX, Arkansas decided to screen out 
Arkansas point sources from further evaluation of additional 
NOX controls, thereby not evaluating the four reasonable 
progress factors for point sources with respect to NOX in 
the first implementation period.
---------------------------------------------------------------------------

    \39\ In developing their Regional Haze SIP and RPGs, Arkansas 
and potentially impacted States collaborated through CENRAP. Each 
State developed its Regional Haze Plans and RPGs based on the CENRAP 
modeling. The CENRAP modeling was based in part on the emissions 
reductions each state intended to achieve by 2018.
    \40\ CENRAP utilized CAMx with its Particulate Source 
Apportionment Technology (PSAT) tool to provide estimated 
contributions to visibility impairment at Class I areas by source 
region (e.g., states) and major source category for both the 
baseline and future case (i.e., 2018) visibility modeling.
---------------------------------------------------------------------------

    With regard to the comment that ``the State's comparison of 
NOX reductions under CSAPR versus the FIP is flawed,'' we 
note that we did not base our proposed approval of the Arkansas 
NOX SIP revision on the state's comparison of these 
NOX reductions. In its draft SIP revision, ADEQ compared 
anticipated NOX emission reductions under CSAPR as compared 
to the source-specific BART determinations required by EPA's FIP in 
assessing the need for additional reductions in NOX to 
ensure reasonable progress. However, in its final SIP, ADEQ did not 
include this information as part of its rationale. We note that our 
proposed approval of Arkansas' SIP revision did not rely on this 
comparison of emissions. As a result, the adequacy of ADEQ's assessment 
is irrelevant to their final action or to our review of the final SIP. 
The commenter's statements questioning ADEQ's assumptions that Arkansas 
EGUs will install and operate NOX combustion controls to 
comply with CSAPR for ozone-season NOX and operate those 
controls year-round appear to be in the context of the commenter's 
contention that ADEQ's comparison of NOX reductions under 
CSARP versus the Arkansas FIP is flawed. As noted above, the adequacy 
of ADEQ's comparison of NOX emissions reductions in the 
proposed SIP revision is irrelevant to their final action or to our 
review of the final SIP.
    Comment: The State failed to consider any of the four statutory 
factors for reasonable progress and the reasonable progress analysis is 
therefore unlawful and not approvable. Arkansas recognizes that ``the 
RHR requires states to consider four factors: (1) Cost of compliance, 
(2) the time necessary for compliance, (3) the energy and non-air 
quality environmental impacts of compliance, and (4) the remaining 
useful life of potentially affected sources,'' but then the State 
proceeds to ignore all four reasonable progress

[[Page 5934]]

factors for point sources in its reasonable progress analysis for 
NOX. The Clean Air Act provides that in determining 
reasonable progress there shall be taken into consideration the costs 
of compliance, the time necessary for compliance, and the energy and 
nonair quality environmental impacts of compliance, and the remaining 
useful life of any existing source subject to such requirements. The 
Act contains no exception to this requirement. The SIP fails to 
consider these four statutory factors, and therefore violates the Clean 
Air Act. In particular, for NOX emissions, the SIP contains 
no analysis of the four factors. For emissions of other pollutants, the 
SIP contains only a single sentence claiming that the cost 
effectiveness for control of POA and CM species from many individual 
small sources is difficult to quantify.
    The SIP's failure to consider any of the four factors for 
NOX controls is particularly egregious given that the State 
acknowledges that EPA has already issued a final rule containing a 
four-factor analysis for the Independence plant, which resulted in a 
requirement that Independence install and operate low-NOX 
burners. The State has produced no evidence that EPA's four-factor 
analysis was incorrect in any way, because the State does not analyze 
any of the four factors which EPA considered.
    Response: We agree that the CAA and the Regional Haze Rule provide 
that in determining reasonable progress, states ``shall take into 
consideration the costs of compliance, the time necessary for 
compliance, the energy and non-air quality environmental impacts of 
compliance, and the remaining useful life of any existing source 
subject to such requirements.'' \41\ However, in cases where it has 
been demonstrated that a particular pollutant or source category does 
not contribute significantly to visibility impairment at affected Class 
I areas, it may be appropriate to end the analysis at that point, 
without the need to evaluate the four statutory factors for potential 
controls to address that pollutant and/or source category. For example, 
EPA's ``Guidance for Setting Reasonable Progress Goals Under the 
Regional Haze Program'' provides that the reasonable progress analysis 
involves identification of key pollutants and source categories that 
contribute to visibility impairment at the Class I area; 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.\42\ 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. As we discussed on our proposed action on 
the Arkansas Regional Haze NOX SIP revision, taking into 
consideration that states have significant discretion in determining 
what sources to analyze for controls under reasonable progress, we 
proposed to agree with the state that it is reasonable for Arkansas to 
reach the conclusion that, for the first implementation period, 
additional NOX controls for Arkansas point sources are not 
anticipated to yield meaningful visibility improvements at Arkansas 
Class I areas in view of the amount of visibility impairment attributed 
to these sources.\43\ Given the level of visibility impairment due to 
NOX from Arkansas point sources at Caney Creek and Upper 
Buffalo on the 20% worst days and considering that Arkansas EGUs are 
participating in CSAPR for ozone season NOX, we find that it 
is reasonable for Arkansas to screen out Arkansas point sources from 
further evaluation of additional NOX controls and therefore 
not have to evaluate the four reasonable progress factors for point 
sources with respect to NOX in the first implementation 
period.
---------------------------------------------------------------------------

    \41\ 42 U.S.C. 7491(g)(1). See also 40 CFR 51.308(d)(1)(i)(A).
    \42\ EPA's ``Guidance for Setting Reasonable Progress Goals 
Under the Regional Haze Program,'' p. 3-1 (June 1, 2007).
    \43\ 82 FR 42633.
---------------------------------------------------------------------------

    Arkansas' conclusions with regard to the percentage contribution to 
light extinction from NO3 on the 20% worst days is generally 
consistent with the findings we made in the Arkansas Regional Haze 
FIP.\44\ In the FIP, we made the finding that NO3 due to 
NOX emissions from point sources is not considered a driver 
of regional haze at Caney Creek and Upper Buffalo on the 20% worst 
days, contributing only approximately 3% of the total light extinction, 
as projected by CENRAP's CAMx source apportionment modeling.\45\ We 
also stated in the FIP proposal that because of the small contribution 
of NO3 from point sources to the total light extinction at 
Caney Creek and Upper Buffalo on the 20% worst days, we did not expect 
that NOX controls under the reasonable progress requirements 
would offer as much improvement on these days compared to 
SO2 controls.\46\ However, in the FIP, we decided to look at 
2011 National Emissions Inventory (NEI) data for NOX for 
Arkansas point sources to determine if there are any large point 
sources that are reasonable candidates for evaluation under the four 
reasonable progress factors. Based on this assessment, we proceeded 
with an analysis of the four reasonable progress factors for 
NOX controls for the Independence facility as we reasoned 
that it is the second largest point source of NOX emissions 
in the state and potentially one of the largest single contributors to 
visibility impairment at Class I areas in Arkansas.\47\ We also 
conducted CALPUFF modeling to determine the maximum 98th percentile 
visibility impacts from the Independence facility and the predicted 
visibility improvement due to NOX controls at the facility. 
That analysis revealed that low NOX burner controls would be 
cost-effective and would result in an improvement of the 98th 
percentile visibility impacts from the Independence facility at Caney 
Creek and Upper Buffalo, and we finalized NOX controls for 
the Independence facility under the reasonable progress 
requirements.\48\ In the Arkansas NOX SIP revision, the 
state takes a different approach in arriving at its decision that no 
additional NOX controls for Arkansas point sources are 
necessary under reasonable progress for the first implementation 
period. In its evaluation, Arkansas places greater emphasis on its 
assessment of the relative contributions to light extinction of sources 
within the State than it does on its assessment of the relative 
contributions of all sources (i.e., sources both in and outside 
Arkansas). Arkansas focused its assessment on the CENRAP's CAMx source 
apportionment modeling and reaches the conclusion that, for the first 
implementation period, additional NOX controls for Arkansas 
point sources are not anticipated to yield meaningful visibility 
improvements at Arkansas Class I areas on the 20% worst days in view of 
the amount of visibility impairment attributed to these sources. 
Therefore, Arkansas determined that no additional NOX 
controls beyond EGU participation in CSAPR for ozone season 
NOX are necessary to satisfy the reasonable progress 
requirements for Arkansas sources in the first planning period. In 
future planning periods, Arkansas will have to reevaluate the benefit 
of NOX reductions, which will likely become more important 
as other pollutants are reduced. We believe Arkansas is within its 
discretion to take

[[Page 5935]]

a different approach than we did in the Arkansas FIP, and that the 
approach Arkansas has taken to determine whether additional 
NOX controls are necessary under reasonable progress is 
reasonable and therefore, approvable. The Clean Air Act gave EPA the 
power to identify pollutants and set air quality standards. Congress 
gave states ``the primary responsibility for implementing those 
standards.'' Luminant Generation Co. v. EPA, 675 F.3d 917, 921 (5th 
Cir. 2012). (internal quotation marks omitted); see 42 U.S.C. 7407(a) 
(``Each State shall have the primary responsibility for assuring air 
quality within [its] entire geographic area.''); id. section 7401(a)(3) 
(``[A]ir pollution prevention . . . is the primary responsibility of 
States and local governments.''). The states have ``wide discretion'' 
in formulating SIPs. Union Elec. Co. v. EPA, 427 U.S. 246, 250 (1976).
---------------------------------------------------------------------------

    \44\ 81 FR 66332; see also 81 FR 68319 (October 4, 2016) 
(correction).
    \45\ 80 FR 18996.
    \46\ 80 FR 18996.
    \47\ 80 FR 18995.
    \48\ 81 FR 66332.
---------------------------------------------------------------------------

    We are finalizing our approval of Arkansas' determination that 
Arkansas EGU participation in CSAPR for ozone season NOX is 
sufficient to satisfy the reasonable progress requirements for 
NOX in Arkansas for the first implementation period.
    Comment: The State's reasonable progress analysis unlawfully fails 
to consider whether measures are needed to make reasonable progress at 
Class I areas outside Arkansas. The State's analysis is unlawful, 
regardless of whether the old or new version of the Regional Haze rule 
applies here. The prior version of the Regional Haze rule required each 
state to make an independent determination of the measures needed to 
make reasonable progress at out-of-state Class I areas. After noting 
the statutory goal to eliminate all human-caused visibility impairment, 
EPA observed that ``it would be impossible to achieve this goal if 
upwind states did not have the same responsibility to address their 
visibility impairing emissions and achieve reasonable progress in 
downwind Class I areas as the downwind states themselves.''
    The current version of the regional haze rule clarifies, but does 
not alter, this obligation. As EPA noted in the 2017 revisions to the 
regional haze rule, states have an ``independent obligation to include 
in their SIPs enforceable emission limits and other measures that are 
necessary to make reasonable progress at all affected Class I areas, as 
determined by considering the four factors.'' Despite the requirement 
to consider whether measures are needed to make reasonable progress at 
out of state Class I areas, the State's analysis focuses exclusively on 
the two Class I areas within Arkansas. Yet the State acknowledges that 
emissions from Arkansas sources impact visibility at Class I areas in 
Missouri. EPA's analysis of the SIP revision commits the same mistake 
as the SIP revision itself. EPA fails to analyze whether the State has 
complied with Clean Air Act requirements to determine whether measures 
are needed to make reasonable progress at out-of-state Class I areas. 
By failing to consider whether measures are necessary to make 
reasonable progress at Missouri Class I areas, the draft SIP violates 
the Regional Haze Rule, and is unapprovable.
    Response: We disagree with the commenter that Arkansas failed to 
consider whether additional controls are necessary to make reasonable 
progress in Class I areas outside the state. The Arkansas 
NOX SIP revision recognizes that sources in Arkansas impact 
the two Class I areas in Missouri: Hercules Glade Wilderness Area and 
Mingo Wilderness Area. Arkansas also explains that ``[t]he most recent 
five-year rolling average of observed visibility impairment on the 
twenty percent haziest days at Hercules Glades Wilderness Area beat 
Missouri's 2018 RPG for that Class I area and the most recent five 
year-rolling average of observed visibility impairment on the twenty 
percent haziest days at Mingo Wilderness Area is on track to beat 
Missouri's RPG for that Class I area.'' \49\ Arkansas concludes that 
the visibility progress observed at the IMPROVE monitors indicates that 
sources in Arkansas are not interfering with the achievement of 
Missouri's 2018 RPGs for Hercules Glades and Mingo Wilderness Areas, 
and that no additional controls are therefore needed on Arkansas 
sources to ensure reasonable progress at Missouri's Class I areas.\50\ 
Furthermore, Arkansas provided Missouri with an opportunity for 
consultation on the Arkansas NOX SIP revision.\51\ Arkansas 
sent a letter dated June 14, 2017, to the Missouri Department of 
Natural Resources (DNR) providing notification and electronic access to 
the proposed SIP revision, and providing an opportunity to discuss 
Missouri's assessment of the impact of the proposed SIP revision on 
reasonable progress at Missouri Class I areas.\52\ Missouri DNR did not 
have comments on Arkansas' proposed SIP revision.
---------------------------------------------------------------------------

    \49\ See final Arkansas NOX SIP revision, Section 
IV.C, p. 23.
    \50\ See final Arkansas NOX SIP revision, Section 
IV.C, p. 23.
    \51\ See final Arkansas NOX SIP revision, Section 
V.C, p. 25.
    \52\ See final Arkansas NOX SIP revision, Tab E.
---------------------------------------------------------------------------

    Comment: The Arkansas Regional Haze NOX SIP revision 
determines that controls for reasonable progress are not necessary for 
the first planning period. The Clean Air Act requires that regional 
haze implementation plans contain measures ``necessary to make 
reasonable progress toward meeting the national goal'' of no manmade 
visibility impairment. In its regulations implementing the Regional 
Haze program, EPA established that, in setting a reasonable progress 
goal, the State must consider the uniform rate of improvement in 
visibility and the emission reduction measures needed to achieve it for 
the period covered by the implementation plan. EPA has further 
explained in its guidance for setting reasonable progress goals that 
states should take into account the fact that the long-term goal of no 
manmade impairment encompasses several planning periods and that it is 
reasonable for the state to defer reductions to later planning periods 
in order to maintain a consistent glidepath toward the long-term goal. 
Mandating emissions controls that are not necessary to make reasonable 
progress during the planning period contradicts this statutory and 
regulatory scheme.
    Reasonable progress controls during the first planning period 
clearly are not necessary for Arkansas sources. Interagency Monitoring 
of Protected Visual Environments (IMPROVE) monitoring data show that 
the haze index has been consistently below the glidepath in Arkansas' 
Class I areas--Caney Creek and Upper Buffalo--and Entergy's analysis 
demonstrates that it is projected to remain so through the end of the 
second planning period.
    Even if controls were required for reasonable progress during the 
first planning period, NOX controls on Arkansas EGUs are not 
necessary, as they will provide minimal visibility improvement in 
Arkansas' Class I areas. As EPA's own analysis indicates, the 
contribution of Arkansas point sources' nitrate emissions to visibility 
impairment in Arkansas' Class I areas is insignificant. According to 
EPA's analysis, nitrate from all point sources included in the regional 
modeling is projected to account for only 3% of the total light 
extinction at the Caney Creek and Upper Buffalo Class I areas, with 
nitrate from Arkansas point sources being responsible for only 0.27% of 
the total light extinction at Caney Creek and 0.14% at Upper Buffalo. 
As a result, NOX controls on Arkansas EGUs during the first 
planning period are not necessary to make reasonable progress towards 
natural visibility conditions.

[[Page 5936]]

    Response: We appreciate the commenter's support of our proposed 
approval of Arkansas' reasonable progress determination for 
NOX. As we had proposed, given the level of visibility 
impairment due to NOX from Arkansas point sources at Caney 
Creek and Upper Buffalo on the 20% worst days and considering that 
Arkansas EGUs are participating in CSAPR for ozone season 
NOX, we are finalizing our determination that Arkansas' 
decision to screen out Arkansas point sources from further evaluation 
of additional NOX controls is reasonable and we are 
finalizing our approval of Arkansas' determination that Arkansas EGU 
participation in CSAPR for ozone season NOX is sufficient to 
satisfy the reasonable progress requirements for NOX in 
Arkansas for the first implementation period.

C. Clean Air Act Section 110(l)

    Comment: EPA asserts that in the SIP revision, Arkansas takes a 
different, but nonetheless equally reasonable, approach to determine 
whether additional controls are necessary under reasonable progress. 
But EPA ignores that the State's ``different'' approach would result in 
more air pollution and worse air quality relative to the existing FIP. 
As a result, the State's reasonable progress determination violates the 
Clean Air Act's ``anti-backsliding'' requirement under 42 U.S.C. 
7410(l), and is therefore unapprovable.
    In the 2016 FIP, EPA determined that reasonable progress requires 
that Independence Units 1 and 2 meet NOX emission limits 
based on the use of low-NOX burners and separated over-fire 
air controls. Now, the State proposes a SIP that would replace those 
NOX emission limits with nothing. Eliminating the 
requirement that a source meet an emission limit necessarily would 
result in greater air pollution and worse visibility impairment at 
affected Class I areas. Section 110(l) of the Clean Air Act prevents a 
plan revision that would weaken the existing FIP requirements in this 
manner.
    Section 110(l) states that the Administrator shall not approve a 
revision of a plan if the revision would interfere with any applicable 
requirement concerning attainment and reasonable further progress or 
any other applicable requirement of this chapter. Section 110(l) is the 
Act's ``anti-backsliding'' provision. The anti-backsliding provision 
prohibits plan revisions that would interfere with attainment of the 
NAAQS or other ``applicable requirements'' of the Act. Section 110(l) 
prohibits plan revisions that would interfere with an existing 
requirement to make reasonable further progress, including a BART 
determination, as the Act's ``applicable requirement[s]'' include the 
regional haze program's BART requirements. When determining whether a 
plan revision interferes with NAAQS attainment, EPA has interpreted 
section 110(l) as preventing plan revisions that would increase overall 
air pollution or worsen air quality. For example, the Eleventh Circuit 
has upheld EPA's section 110(l) interpretation as prohibiting plan 
revisions that would increase emissions or worsen air quality. In 
Kentucky Resources Council, Inc. v. EPA, 467 F.3d 986 (6th Cir. 2006), 
EPA interpreted section 110(l) as allowing the agency to approve a plan 
revision that weakened some existing control measures while 
strengthening others, but only ``[a]s long as actual emissions in the 
air are not increased.'' The court upheld EPA's interpretation, which 
``allow[ed] the agency to approve a [state implementation plan] SIP 
revision unless the agency finds it will make the air quality worse.'' 
The Seventh Circuit has also upheld EPA's interpretation in Indiana v. 
EPA, 796 F.3d 803, 812 (7th Cir. 2015). Moreover, in a short discussion 
regarding a challenge to the Nevada regional haze plan in WildEarth 
Guardians v. EPA, 759 F.3d 1064, 1074 (9th Cir. 2014), the Ninth 
Circuit suggested that a haze plan that ``weakens or removes any 
pollution controls'' would violate section 110(l).
    The existing reasonable progress determination in the FIP requires 
Independence Units 1 and 2 to meet emission limits based on the use of 
low-NOX burners and separated over-fire air. These pollution 
reductions must occur by April 27, 2018. EPA has proposed to extend the 
compliance deadline for this requirement, but has not proposed to alter 
the emission limits themselves. Even if the deadline extension is 
finalized, the final FIP for Arkansas requires Independence Units 1 and 
2 to reduce NOX emissions. The draft SIP would eliminate the 
FIP requirements for Independence without imposing any other 
requirement that would achieve equal or greater reductions in 
NOX emissions from Independence.
    Response: We disagree that the Arkansas NOX SIP revision 
violates the CAA's requirements under section 110(l). As discussed in 
our proposed approval of the Arkansas NOX SIP revision, we 
believe an approval of the SIP revision and concurrent withdrawal of 
the corresponding parts of the FIP, as proposed, will meet the Clean 
Air Act's 110(1) provisions. Generally, a SIP revision may be approved 
under section 110(l) if EPA finds that it will at least preserve status 
quo air quality, particularly where the pollutants at issue are those 
for which an area has not been designated nonattainment.\53\ Approval 
of the Arkansas NOX SIP revision is not expected to 
interfere with attainment and maintenance of any of the NAAQS within 
the state of Arkansas. No areas in Arkansas are currently designated 
nonattainment for any NAAQS pollutants. The SIP revision we are 
approving would allow Arkansas to rely on compliance with CSAPR for 
ozone-season NOX to satisfy the NOX BART 
requirement for Arkansas EGUs and makes the determination that no 
additional NOX controls beyond EGU participation in CSAPR 
for ozone season NOX are necessary to satisfy the reasonable 
progress requirements for NOX for Arkansas sources. While 
the commenter is correct that the Arkansas NOX SIP revision 
we are approving does not require source-specific NOX 
controls under reasonable progress for Independence Units 1 and 2, as 
was required by the FIP, we note that those units are subject to CSAPR 
for ozone season NOX and their NOX emissions will 
thus be addressed through participation in the CSAPR ozone season 
NOX program. Further, the CSAPR 2018 NOX ozone 
season allocations for Arkansas sources are more stringent than the 
2017 allocations. As all areas in Arkansas are attaining all the NAAQS 
even with current emissions levels, compliance with the CSAPR 2018 
NOX ozone season more stringent allocations will not 
interfere with any applicable requirement concerning attainment or 
reasonable further progress toward attainment of the NAAQS. We are not 
aware of any basis for concluding or demonstrating that the Arkansas 
NOX SIP revision, when implemented, would interfere with the 
continued attainment of all the NAAQS in Arkansas.
---------------------------------------------------------------------------

    \53\ 78 FR 51686 at 51694 (August 21, 2013).
---------------------------------------------------------------------------

    We also do not find that our approval of the Arkansas 
NOX SIP revision, as proposed, will interfere with the 
applicable CAA regional haze requirements for BART or reasonable 
progress because our action is supported by an evaluation that those 
CAA regional haze requirements for BART and reasonable progress are 
met. Specifically, EPA has made the determination that Arkansas EGU 
participation in CSAPR for ozone-season NOX satisfies the 
NOX BART requirements for Arkansas EGUs, consistent with 40 
CFR 51.308(e)(4). On September 29, 2017, we affirmed our proposed 
finding that the EPA's 2012

[[Page 5937]]

analytical demonstration remains valid and that participation in CSAPR, 
as it now exists, meets the Regional Haze Rule's criteria for an 
alternative to BART. With regard to reasonable progress for regional 
haze, the Arkansas NOX SIP revision includes an assessment 
of anthropogenic sources of visibility impairment and arrives at the 
determination that given the level of contribution to light extinction 
from NOX due to Arkansas point sources, Arkansas EGU 
participation in CSAPR for ozone season NOX is sufficient to 
satisfy the reasonable progress requirements for NOX in 
Arkansas for the first implementation period. The Independence 
facility, on which the FIP imposed source specific NOX 
controls under the reasonable progress requirements, is subject to 
CSAPR for ozone season NOX. Even though we are approving the 
Arkansas NOX SIP revision and concurrently withdrawing the 
source-specific NOX controls in the FIP for the Independence 
facility, the NOX emissions from the Independence facility 
will still be addressed under the regional haze reasonable progress 
requirements through participation in the CSAPR ozone season 
NOX emissions trading program. In addition, all Arkansas 
EGUs with a nameplate capacity of 25 megawatts or greater participate 
in the CSAPR ozone season NOX emissions trading program. 
This means that many EGUs that were not subject to control requirements 
under the FIP are required under the CSAPR trading program to comply 
with specific NOX emissions allocations during the ozone 
season.

D. Legal

    Comment: To be approvable, any SIP must include enforceable 
emissions limitations, compliance schedules, and other measures as 
necessary to achieve the reasonable progress goals. The agency 
recognized in disapproving Arkansas's 2011 SIP package, that when 
evaluating a state's BART determination, the EPA looks at existing 
requirements and cannot rely on potential future actions in its 
decision to approve or disapprove a state SIP. Here, EPA's proposed 
approval is impermissibly based on future contingencies that have not 
occurred. Indeed, the agency recognized in the proposal that it cannot 
take a final action until the state completes its rulemaking process, 
adopts its final regulations, and submits these final adopted 
regulations as a revision to the Arkansas SIP. Because EPA's proposed 
action relies on potential future state actions, it cannot be approved.
    Response: We disagree with comments that we are relying on 
potential future state actions in taking final action. CSAPR is an 
existing program that the state of Arkansas is participating in for 
NOX. The Arkansas SIP revision relies on participation in 
CSAPR to meet the requirements of NOX BART, as well as the 
fact that NOX is not the driver of visibility impairment on 
the 20% worst days, in their determination under reasonable progress, 
that no other NOX controls are needed. Future decisions on 
trading as part of its current participation in CSAPR are not 
considered future state actions. Current participation in CSAPR is the 
state action that EPA's proposed action is based upon.
    Further, our proposed approval was based on a proposed SIP revision 
submitted by ADEQ on July 12, 2017, with a request for parallel 
processing. As we explained in our September 11, 2017 proposal, we 
proposed action on the SIP revision at the same time that ADEQ was 
completing the corresponding public comment and rulemaking process at 
the state level.\54\ We explained that the July 2017 SIP revision 
request would not be complete and would not meet all the SIP 
approvability criteria until the state completes the public process and 
submits the final, adopted SIP revision with a letter from the Governor 
or Governor's designee to EPA.\55\ In our September 11, 2017 proposal, 
we proposed to approve the SIP revision request after completion of the 
state public process and final submittal of the SIP revision. On 
October 31, 2017, we received ADEQ's final SIP revision addressing BART 
and reasonable progress requirements for NOX for EGUs in 
Arkansas for the first implementation period. The final Arkansas 
Regional Haze NOX SIP revision we received on October 31, 
2017 did not contain significant changes from the state's proposed SIP 
revision. Therefore, it is appropriate for us to take final action, as 
proposed, on the final SIP revision.
---------------------------------------------------------------------------

    \54\ 82 FR at 42629.
    \55\ Id.
---------------------------------------------------------------------------

E. General

    Comment: The proposed rule contains certain calculation errors, 
which, although sufficiently minor that they do not affect EPA's 
conclusions, should be corrected. EPA states that total light 
extinction on the 20% worst days in 2002 was 115.87 Mm-1 for 
Caney Creek and 115 Mm-1 for Upper Buffalo. These values are 
inconsistent with CENRAP PSAT results, which are 133.93 Mm-1 
and 131.79 Mm-1, respectively. EPA's values appear to 
exclude certain source categories, namely Initial Conditions, Boundary 
Conditions, Secondary Organic Aerosols--Anthropogenic, and Secondary 
Organic Aerosols--Biogenic. EPA does not explain why these categories 
are or should be excluded when calculating light extinction on the 20% 
worst days in 2002. Further, EPA does include these categories in its 
calculation of other values, such as the 87.05 Mm-1 value 
for the SO4 contribution at Caney Creek, which accounts for 
3.32 Mm-1 from the Boundary Conditions source category. 
Because the total light extinction values form the basis for many other 
values in EPA's analysis, errors in the total light extinction values 
carry over into the derivative values.
    The proposed rule also contains a number of miscalculations 
unrelated to the total light extinction error. These miscalculations 
relate to EPA's characterization of the CENRAP PSAT results. While 
sufficiently minor that they do not affect the outcome of EPA's 
determination, Entergy lists these errors here in the interest of 
correcting the record:
     EPA states that the remaining source categories each 
contribute between 2% and 6% of total light extinction at Arkansas' 
Class I areas. The high-end rounded value should be changed from 6% to 
7%, as the true range is 1.83% to 6.72%, pursuant to the CENRAP PSAT 
results.
     EPA states that the PSAT results show that natural, on-
road, and non-road sources are projected to continue to contribute a 
very small portion of total light extinction at Arkansas' Class I areas 
on the 20% worst days in 2018. According to the CENRAP PSAT results, 
the contribution of natural, on-road, and non-road sources is 8.5% to 
9.4% of the total light extinction. This amount should not be 
characterized as ``a very small portion.''
     EPA states that the other species (i.e., NO3, 
POA, EC, soil, and CM) are also projected to have reductions in their 
contribution to total light extinction at Caney Creek and Upper Buffalo 
in 2018. This statement is true for all the species except soil, which 
actually increases in 2018 for both Class I areas according to the 
CENRAP PSAT results.
     EPA states that the other source categories in Arkansas 
each contribute between 7% and 14% to light extinction attributed to 
Arkansas sources at Caney Creek and Upper Buffalo. According to the 
CENRAP PSAT results, the correct range is 7% to 8%.
     EPA states that CM from Arkansas sources, primarily area 
sources,

[[Page 5938]]

contribute approximately 1 and 2% of total light extinction at Caney 
Creek and Upper Buffalo, respectively. According to the CENRAP PSAT 
results, the value for Upper Buffalo is 2.68% (which would round to 
3%).
    Response: We appreciate the commenter pointing out errors and other 
mischaracterizations of light extinction values presented in our 
proposed action. We acknowledge these errors. As pointed out by the 
commenter, these errors are minor in nature and do not affect our 
proposed and final determinations on the Arkansas Regional Haze 
NOX SIP revision.
     The commenter is correct that our proposed action stated 
that total light extinction on the 20% worst days in 2002 was 115.87 Mm 
-1 for Caney Creek and 115 Mm -1 for Upper 
Buffalo.\56\ However, as pointed out by the commenter, these cited 
values did not include initial conditions, boundary conditions, and 
secondary organic matter. As we noted in our proposed action on the 
2008 Arkansas Regional Haze SIP,\57\ the correct total visibility 
extinction on the 20% worst days in 2002, including contributions from 
initial conditions, boundary conditions, and secondary organic matter, 
is 133.93 Mm -1 at Caney Creek \58\ and 131.79 Mm 
-1 at Upper Buffalo.\59\
---------------------------------------------------------------------------

    \56\ 82 FR at 42630.
    \57\ 76 FR at 64186 (October 17, 2011).
    \58\ 76 FR at 64214.
    \59\ 76 FR at 64215.
---------------------------------------------------------------------------

     The commenter pointed out that we stated in our proposal 
that the PSAT results show that natural, on-road, and non-road sources 
are projected to contribute a very small portion of total light 
extinction at Arkansas' Class I areas on the 20% worst days in 
2018.\60\ The commenter further points out that the combined 
contribution of these three source categories is 8.5% and 9.4% at Caney 
Creek and Upper Buffalo, which the commenter says should not be 
characterized as ``a very small portion.'' While we agree with the 
commenter that the combined contribution of the three source categories 
is not ``very small,'' we would like to clarify that the statement made 
in our proposal referred to the contribution of each individual source 
category at each Class I area. For example, the natural source category 
contributes approximately 2.47% of the total light extinction at Caney 
Creek and 2.6% at Upper Buffalo on the 20% worst days in 2018; the on-
road source category contributes approximately 1.68% of the total light 
extinction at Caney Creek and 1.82% at Upper Buffalo; and the on-road 
source category contributes approximately 4.38% of the total light 
extinction at Caney Creek and 4.93% at Upper Buffalo.
---------------------------------------------------------------------------

    \60\ 82 FR 42631.
---------------------------------------------------------------------------

     The commenter pointed out that our statement that the 
light extinction due to species other than SO4 is projected 
to decrease in 2018 on the 20% worst days at Caney Creek and Upper 
Buffalo is correct for all species except soil. The commenter is 
correct, as the light extinction due to soil is projected to increase 
slightly in 2018 on the 20% worst days at both Class I areas.\61\ The 
commenter points out that according to the CENRAP PSAT results, CM from 
Arkansas sources contribute approximately 2.68% of the total light 
extinction at Upper Buffalo, not 2%, as stated in our proposal.\62\ The 
commenter is correct. The CM contribution from all Arkansas source 
categories is 3.53 Mm -1, out of a total light extinction of 
131.79 Mm -1, which is a contribution of approximately 
2.68%.
---------------------------------------------------------------------------

    \61\ 76 FR at 64214-64215; see Tables 8 and 10.
    \62\ 82 FR at 42631.
---------------------------------------------------------------------------

IV. Final Action

    We are approving a revision to the Arkansas SIP submitted on 
October 31, 2017, 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 51.300-51.308. The EPA 
is approving the SIP revision submittal as meeting the following: the 
core requirements for regional haze SIPs found in 40 CFR 51.308(d) such 
as the reasonable progress requirement for NOX; the 
NOX BART requirements for regional haze visibility 
impairment with respect to emissions of visibility impairing pollutants 
from EGUs in 40 CFR 51.308(e); and the requirement for coordination 
with state and Federal Land Managers in Sec.  51.308(i). We are 
approving ADEQ's reliance on CSAPR participation for ozone season 
NOX to meet the NOX BART requirement for EGUs. 
Arkansas' reliance on CSAPR addresses 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 the 
Auxiliary Boiler.
    We also agree that Arkansas' conclusion that given the relatively 
small level of visibility impairment due to NOX from 
Arkansas point sources at Caney Creek and Upper Buffalo on the 20% 
worst days, for the first implementation period, additional 
NOX controls for Arkansas point sources are not anticipated 
to yield meaningful visibility improvements at Arkansas Class I areas 
on the 20% worst days is reasonable. In light of the level of 
visibility impairment due to NOX from Arkansas point sources 
at Caney Creek and Upper Buffalo and considering that Arkansas EGUs are 
participating in CSAPR for ozone season NOX, we are 
finalizing our determination that Arkansas' decision to screen out 
Arkansas point sources from further evaluation of additional 
NOX controls is reasonable and we are finalizing our 
approval of Arkansas' determination that no additional NOX 
controls, beyond Arkansas EGU participation in CSAPR for ozone season 
NOX, are necessary to satisfy the reasonable progress 
requirements for NOX in Arkansas for the first 
implementation period.
    Concurrent with our final approval of the Arkansas Regional Haze 
NOX 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 NOX requirements on 
Bailey Unit 1; McClellan Unit 1; Flint Creek Boiler No. 1; Lake 
Catherine Unit 4; White Bluff Units 1 and 2 and the Auxiliary Boiler; 
and Independence Units 1 and 2.\63\
---------------------------------------------------------------------------

    \63\ Our final action withdrawing part of the Arkansas Regional 
Haze FIP is also being published in this Federal Register.
---------------------------------------------------------------------------

    We find that an approval of the SIP revision meets the Clean Air 
Act's 110(1) provisions. No areas in Arkansas are currently designated 
nonattainment for any NAAQS pollutants. Approval of the Arkansas 
NOX SIP revision will not interfere with continued 
attainment of all the NAAQS within the state of Arkansas. The SIP 
revision we are approving would allow Arkansas to rely on compliance 
with CSAPR for ozone-season NOX to satisfy the 
NOX BART requirement for Arkansas EGUs and makes the 
determination that no additional NOX controls beyond EGU 
participation in CSAPR for ozone season NOX are necessary to 
satisfy the reasonable progress requirements for NOX for 
Arkansas sources. We also find that our approval of the Arkansas 
NOX SIP revision will not interfere with the applicable CAA 
regional haze requirements for BART because our action is supported by 
an evaluation EPA made in a separate rulemaking \64\ that the CAA 
requirement for BART can be satisfied through participation in

[[Page 5939]]

CSAPR. We also find that our approval of the Arkansas NOX 
SIP revision will not interfere with the applicable CAA regional haze 
requirements for reasonable progress because the Arkansas 
NOX SIP revision includes an assessment of anthropogenic 
sources of visibility impairment and arrives at the determination that 
given the level of contribution to light extinction from NOX 
due to Arkansas point sources, Arkansas EGU participation in CSAPR for 
ozone season NOX is sufficient to satisfy the reasonable 
progress requirements for NOX in Arkansas for the first 
implementation period. The Independence facility, on which the FIP 
imposed source specific NOX controls under the reasonable 
progress requirements, is subject to CSAPR for ozone season 
NOX. Even though we are approving the Arkansas 
NOX SIP revision and concurrently withdrawing the source-
specific NOX controls in the FIP for the Independence 
facility, the NOX emissions from the Independence facility 
will still be addressed under the regional haze reasonable progress 
requirements through participation in the CSAPR ozone season 
NOX emissions trading program.
---------------------------------------------------------------------------

    \64\ On September 29, 2017, we finalized our proposed finding 
that the EPA's 2012 analytical demonstration remains valid and that 
participation in CSAPR, as it now exists, meets the Regional Haze 
Rule's criteria for an alternative to BART.
---------------------------------------------------------------------------

V. Statutory and Executive Order Reviews

    Under the Clean Air Act, the Administrator is required to approve a 
SIP submission that complies with the provisions of the Act and 
applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). 
Thus, in reviewing SIP submissions, 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 April 13, 2018. 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

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

    Dated: January 24, 2018.
Anne Idsal,
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, paragraph (e) is amended by adding the entry 
``Arkansas Regional Haze NOX SIP Revision'' at the end of 
the third table titled ``EPA-Approved Non-Regulatory Provisions and 
Quasi-Regulatory Measures in the Arkansas SIP'' to read as follows:

Sec.  52.170  Identification of plan.

* * * * *
    (e) * * *

[[Page 5940]]

            EPA-Approved Non-Regulatory Provisions and Quasi-Regulatory Measures in the Arkansas SIP
----------------------------------------------------------------------------------------------------------------
                                                                 State
     Name of SIP provision        Applicable geographic or    submittal/    EPA approval date     Explanation
                                     nonattainment area     effective date
----------------------------------------------------------------------------------------------------------------
 
                                                  * * * * * * *
Arkansas Regional Haze NOX SIP   Statewide................      10/31/2017  2/12/2018,         Regional Haze SIP
 Revision.                                                                   [Insert Federal    submittal
                                                                             Register           addressing NOX
                                                                             citation].         BART
                                                                                                requirements for
                                                                                                Arkansas EGUs
                                                                                                and reasonable
                                                                                                progress
                                                                                                requirements for
                                                                                                NOX for the
                                                                                                first
                                                                                                implementation
                                                                                                period.
----------------------------------------------------------------------------------------------------------------

0
3. In Sec.  52.173, paragraphs (e) and (f) are added to read as 
follows:

Sec.  52.173  Visibility protection.

* * * * *
    (e) Measures addressing best available retrofit technology (BART) 
for electric generating unit (EGU) emissions of nitrogen oxides (NOX). 
The BART requirements for EGU NOX emissions are satisfied by 
Sec.  52.184 and the Arkansas Regional Haze NOX SIP Revision 
approved February 12, 2018, [Insert Federal Register citation].
    (f) Other measures addressing reasonable progress. The reasonable 
progress requirements for NOX emissions are satisfied by the 
Arkansas Regional Haze NOX SIP Revision approved February 
12, 2018, [Insert Federal Register citation].

[FR Doc. 2018-02147 Filed 2-9-18; 8:45 am]
 BILLING CODE 6560-50-P