[Federal Register Volume 82, Number 194 (Tuesday, October 10, 2017)]
[Rules and Regulations]
[Pages 46903-46915]
[FR Doc No: 2017-21604]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2017-0092, FRL-9968-97-Region 9]

Approval and Promulgation of Air Quality Implementation Plans;
Arizona; Regional Haze State and Federal Implementation Plans

AGENCY: Environmental Protection Agency (EPA).

ACTION: Final rule.

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SUMMARY: The Environmental Protection Agency (EPA) is approving a
source-specific revision to the Arizona state implementation plan (SIP)
that provides an alternative to Best Available Retrofit Technology
(BART) for the Coronado Generating Station (``Coronado''), owned and
operated by the Salt River Project Agricultural Improvement and Power
District (SRP). The EPA has determined that the BART alternative for
Coronado would provide greater reasonable progress toward natural
visibility conditions than BART, based on the criteria established in
the EPA's Regional Haze Rule. In conjunction with this approval, we are
withdrawing those portions of the federal implementation plan (FIP)
that address BART for Coronado. We are also codifying the removal of
those portions of the Arizona SIP that have either been superseded by
this approval of the SIP revision for Coronado or by previously-
approved revisions to the Arizona SIP.

DATES: This rule is effective November 9, 2017.

ADDRESSES: The EPA has established Docket ID No. EPA-R09-OAR-2017-0092
for this action. All documents in the docket are listed on the http://www.regulations.gov Web site. Although listed in the index, some
information is not publicly available, e.g., Confidential Business
Information (CBI) or other information whose disclosure is restricted
by statute. Certain other material, such as copyrighted material, is
not placed on the Internet and will be publicly available only in hard
copy form. Publicly available docket materials are available through
http://www.regulations.gov, or please contact the person identified in
the FOR FURTHER INFORMATION CONTACT section for additional availability
information.

FOR FURTHER INFORMATION CONTACT: Krishna Viswanathan, EPA, Region IX,
Air Division, Air Planning Office,<PHONE_NUMBER> or
<EMAIL_ADDRESS>
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' refer to the EPA.

Table of Contents

I. General Information
II. Proposed Action
III. Public Comments and EPA Responses
IV. Final Action
V. Environmental Justice Considerations
VI. Incorporation by Reference
VII. Statutory and Executive Order Reviews

I. General Information

Definitions

    For the purpose of this document, we are giving meaning to certain
words or initials as follows:
     The initials ADEQ mean or refer to the Arizona Department
of Environmental Quality.
     The words Arizona and State mean the State of Arizona.
     The word Coronado refers to the Coronado Generating
Station.
     The initials BART mean or refer to Best Available Retrofit
Technology.
     The initials BOD mean or refer to boiler operating day.
     The term Class I area refers to a mandatory Class I
Federal area.\1\
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    \1\ 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. When we use the term ``Class I area'' in this action,
we mean a ``mandatory Class I Federal area.''
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     The initials CAA mean or refer to the Clean Air Act.
     The words EPA, we, us, or our mean or refer to the United
States Environmental Protection Agency.
     The initials FIP mean or refer to federal implementation
plan.
     The initials lb/MMBtu mean or refer to pounds per million
British thermal units.
     The initials NAAQS mean or refer to National Ambient Air
Quality Standards.

     The initials NOX mean or refer to nitrogen oxides.
     The initials PM mean or refer to particulate matter, which
is inclusive of PM10 (particulate matter less than or equal
to 10 micrometers) and PM2.5 (particulate matter less than
or equal to 2.5 micrometers).
     The initials SCR mean or refer to selective catalytic
reduction.
     The initials SIP mean or refer to state implementation
plan.
     The initials SO2 mean or refer to sulfur dioxide.
     The initials SRP mean or refer to the Salt River Project
Agricultural Improvement and Power District.
     The initials tpy mean or refer to tons per year.

II. Proposed Action

    On April 27, 2017, the EPA proposed to approve a revision to the
Arizona Regional Haze SIP for Coronado (``Coronado SIP Revision'') \2\
that provides an alternative to BART for Coronado (``Coronado BART
Alternative'').\3\ The Coronado SIP Revision and BART Alternative
consist of an interim operating strategy (``Interim Strategy'') that
will take effect on December 5, 2017, and a final operating strategy
(``Final Strategy'') that will take effect no later than December 31,
2025. The Coronado BART Alternative was submitted pursuant to
provisions of the Regional Haze Rule that allows states to adopt
alternative measures in lieu of source-specific BART controls if they
can demonstrate that the alternative measures provide greater
reasonable progress towards natural visibility conditions than BART.\4\
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    \2\ As noted in our proposal, the Coronado SIP Revision includes
both the original version of the revision (dated July 19, 2016) that
was proposed by the Arizona Department of Environmental Quality
(ADEQ) for public comment, and an addendum (``Addendum'' dated
November 10, 2016), in addition to various supporting materials. The
Addendum documents changes to the Coronado BART Alternative since
ADEQ's July 19, 2016 proposal. Unless otherwise specified,
references in this document to the Coronado SIP Revision include
both of these documents, as well as the other materials included in
ADEQ's submittal.
    \3\ 82 FR 19333. Please refer to the notice of proposed
rulemaking for background information concerning the CAA, the
Regional Haze Rule, and the Arizona Regional Haze SIP and FIP, and a
detailed analysis of the Coronado BART Alternative.
    \4\ 40 CFR 51.308(e)(2) and (3).
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    The Interim Strategy includes three different operating options,
each of which requires a period of seasonal curtailment (i.e.,
temporary closure) for Unit 1. Each year, SRP must select and implement
one of the three options based on the nitrogen oxides (NOX)
emissions performance of Unit 1 and the sulfur dioxide (SO2)
emissions performance of Units 1 and 2 in that year. In addition, under
each option, the facility must comply with an annual SO2
emissions cap of 1,970 tons per year (tpy) from Unit 1 and Unit 2
effective beginning in 2018. The Final Strategy in the Coronado SIP
Revision requires the installation of selective catalytic reduction
(SCR) on Unit 1 (``SCR Option'') or the permanent cessation of
operation of Unit 1 (``Shutdown Option'') no later than December 31,
2025. SRP is required to notify ADEQ and the EPA of its selection of
either the SCR Option or the Shutdown Option by December 31, 2022. The
Final Strategy includes two additional features: An SO2
emission limit of 0.060 lb/MMBtu, calculated on a 30-boiler operating
day (BOD) rolling average, which applies to Unit 2 (as well as Unit 1
if it continues operating), and an annual SO2 emissions cap
of either 1,970 tpy from Unit 1 and Unit 2, if both units continue
operating, or 1,080 tpy if Unit 1 shuts down. ADEQ incorporated the
revised emission limits, as well as associated compliance deadlines and
monitoring, recordkeeping, and reporting requirements, as a permit
revision to Coronado's existing Operating Permit, which was submitted
as part of the Coronado SIP Revision (``Coronado Permit Revision'').\5\
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    \5\ Coronado SIP Revision, Appendix B, Permit No. 64169 as
amended by Significant Revision to operating permit No. 63088
(December 14, 2016). The provisions implementing the Coronado BART
Alternative are incorporated in Attachment E to the permit.
Attachment E will become effective under State law on the date of
the EPA's final action to approve Attachment E into the Arizona SIP
and rescind the provisions of the Arizona Regional Haze FIP that
apply to Coronado. Id. Attachment E, section I.A.
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    We proposed to approve the Coronado SIP Revision because in our
assessment it complied with the relevant requirements of the CAA and
the Regional Haze Rule. In particular, we proposed to find that the
Coronado BART Alternative would achieve greater reasonable progress
towards natural visibility conditions than would be achieved through
the installation and operation of BART at Coronado.\6\ Because this
approval would fill the gap in the Arizona Regional Haze SIP left by
the EPA's prior partial disapproval with respect to Coronado, we also
proposed to withdraw the provisions of the Arizona Regional Haze FIP
that apply to Coronado. Finally, we proposed revisions to 40 CFR part
52 to codify the removal of those portions of the Arizona Regional Haze
SIP that have either been superseded by previously-approved revisions
to the Arizona SIP or would be superseded by final approval of the
Coronado SIP Revision.
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    \6\ For purposes of our evaluation, we consider BART for
Coronado to consist of a combination of (1) ADEQ's BART
determinations for PM10 and SO2, which were
approved into the applicable SIP, and (2) the EPA's BART
determination for NOX in the 2016 BART Reconsideration
(collectively the ``Coronado BART Control Strategy''). See 82 FR
19337.
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III. Public Comments and EPA Responses

    The EPA's proposed action provided a 45-day public comment period.
During this period, we received comment letters from Earthjustice (on
behalf of the Sierra Club and the National Parks Conservation
Association),\7\ Environmental Defense Fund (EDF),\8\ SRP,\9\ and two
anonymous commenters. Summaries of significant comments and our
responses are provided below.
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    \7\ Letter from Michael Hiatt, Earthjustice, to Krishna
Viswanathan, EPA (June 12, 2017) (``Earthjustice comment letter'').
    \8\ Letter from Bruce Polkowsky and Graham McCahan, EDF, to
Krishna Viswanathan, EPA (June 12, 2017) (``EDF comment letter'').
    \9\ Letter from Kelly Barr, SRP, to Krishna Viswanathan, EPA
(June 12, 2017) (``SRP comment letter'').
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Comments From Non-Governmental Organizations

    Comment: Earthjustice argued that the EPA should not approve the
Coronado BART Alternative because ADEQ and SRP's rationale for
replacing the original BART determination with the BART Alternative is
now invalid. Citing several administrative law cases, the commenter
stated that the EPA must provide a valid rationale for issuing any
regulation, including an approval or disapproval of a SIP, given that
standard Administrative Procedure Act (APA) requirements apply to such
actions. The commenter noted that both ADEQ and SRP had indicated that
the purpose of the Coronado BART Alternative was to delay Unit 1's BART
obligations until SRP knew whether it would choose to retire Coronado
to comply with the Clean Power Plan (CPP). In particular, the commenter
cited statements in the Coronado SIP Revision that referred to
regulatory uncertainty related to the CPP. The commenter noted that the
``EPA and the new administration have taken multiple actions to
indefinitely suspend and review the [CPP]'' and asserted that these
actions undercut ADEQ's rationale for replacing the original BART
determination with the Coronado BART Alternative.
    Earthjustice acknowledged that the EPA did not discuss the CPP in
our proposal. However, citing Arizona v. EPA, 815 F.3d 519, 531 (9th
Cir. 2016),

in which the Ninth Circuit upheld the EPA's disapproval of ADEQ's
original NOX BART determination for Coronado, the commenter
asserted that, ``if ADEQ's plan is based on an invalid rationale it is
unreasonable, and EPA's approval of the plan would also necessarily be
unreasonable and arbitrary.'' The commenter argued that the ``EPA
cannot cure this fatal flaw with the BART alternative by attempting to
come up with other rationales for the alternative in response to these
comments.''
    Earthjustice further asserted that ADEQ should ``propose a new BART
revision that is based on a valid rationale.'' The commenter also noted
that SRP could comply with the existing BART determination by shutting
down Unit 1 and asserted that ``this result would be consistent with
other recent decisions across Arizona to shut down coal plants or
switch them to gas.''
    Response: We agree with the commenter that APA requirements
generally apply to the EPA's approval or disapproval of a SIP revision
and that we must provide a reasoned justification for such actions.\10\
We also agree with the commenter that both ADEQ and SRP previously
indicated that the Coronado BART Alternative was developed to align
SRP's compliance obligations under the CPP and the Regional Haze Rule.
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    \10\ We note that the EPA is issuing this final rule under
section 307(d) of the CAA, which provides that that: ``[t]he
provisions of section 553 through 557 . . . of [the APA] shall not,
except as expressly provided in this section, apply to actions to
which [CAA section 307(d)] applies.'' 42 U.S.C. 7607(d)(1).
Nonetheless, pursuant to CAA section 307(d)(9)(A), the same
arbitrary-and-capricious standard of review applies to an action
under 307(d) as to an action subject to the APA.
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    In reviewing a SIP submittal, however, the EPA's role is to
evaluate whether the submittal meets the applicable requirements of the
CAA and the EPA's regulations. If these requirements are met, the EPA
must approve the submittal.\11\ As noted by the commenter, ``the EPA
does not usurp a state's authority but ensures that such authority is
reasonably exercised.'' \12\ However, the state's underlying motivation
in submitting the SIP revision, which the commenter refers to as the
state's ``rationale'' is not one of the elements that the EPA is
required to evaluate under the CAA. Therefore, in acting on the
Coronado SIP Revision, we have not considered the state's motivation in
developing the SIP revision. Rather, as described in our proposal and
elsewhere in this document, we have evaluated the Coronado SIP Revision
in relation to the relevant requirements of the CAA and the EPA's
regulations, and we have determined that it meets all of these
requirements. In particular, the Coronado SIP Revision includes
detailed and technically sound analyses supporting the State's
determination that the Coronado BART Alternative would provide greater
reasonable progress toward natural visibility conditions than BART. In
contrast to the flawed analyses underlying ADEQ's original
NOX BART determination for Coronado, which we disapproved,
the analyses supporting the Coronado BART Alternative were both
``reasoned [and] moored to the [Act]'s provisions,'' \13\ for the
reasons explained in our proposal and elsewhere in this document.
Therefore, the commenter's reliance on the decision of the Ninth
Circuit in Arizona v. EPA, which upheld that prior disapproval, is
misplaced.
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    \11\ See CAA section 110(k)(3), 42 U.S.C. 7410(k)(3) (``[T]he)
Administrator shall approve such submittal as a whole if it meets
all of the applicable requirements of [the CAA].'' (emphasis
added)).
    \12\ 82 FR 15139, 15142 (March 27, 2017).
    \13\ Arizona v. EPA, 815 F.3d 519, 531 (9th Cir. 2016) (quoting
North Dakota v. EPA, 730 F.3d 750, 761 (8th Cir. 2013)).
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    Furthermore, the State's analyses supporting its determination of
greater reasonable progress do not rely on the requirements of the CPP
or any uncertainty related to those requirements. While the State
included a discussion of the CPP in its proposed SIP revision to
explain the proposed compliance schedule for the Coronado BART
Alternative,\14\ the Addendum, which reflects the final requirements of
the Coronado SIP Revision, includes a different compliance schedule and
no mention of the CPP.
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    \14\ See Coronado SIP Revision (July 19, 2016), at 2-3.
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    Finally, while the commenter is correct that SRP could choose to
comply with the existing BART determination for Coronado Unit 1 by
simply shutting down that unit, this fact has no bearing on the
approvability of the Coronado SIP Revision. Likewise, the fact that the
owners of units of other coal plants in Arizona have chosen to shut
down units or switch them to natural gas is not pertinent to the
current action.\15\
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    \15\ We also note that, contrary to the commenters' suggestion,
none of the cited examples involve a shutdown or switch to gas to
comply with the original BART determination for the facility. The
switch to natural gas at Apache Generating Station Unit 2 is part of
a BART alternative that replaced the original BART determinations
for that facility. See 80 FR 19220 (April 10, 2017). The closure of
Cholla Generating Station Unit 2 and cessation of coal burning at
Units 3 and 4 are part of a BART reassessment that replaced the
original BART determinations for that facility. See 82 FR 15139
(March 27, 2017). Finally, as noted by the commenter, the possible
closure of Navajo Generating Station is due to economic factors.
See, e.g., Ryan Randazzo, Utilities vote to close Navajo coal plant
at end of 2019, Arizona Republic (February 13, 2017).
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    Comment: EDF and Earthjustice both objected to the EPA's and ADEQ's
reliance on the two-prong modeling test under 40 CFR 51.308(e)(3) to
demonstrate that the Interim Strategy would achieve greater reasonable
progress than the Coronado BART Alternative. The commenters noted that
40 CFR 51.308(e)(3) outlines two different tests for evaluating whether
a BART alternative achieves greater reasonable progress than BART. In
particular, 40 CFR 51.308(e)(3) provides that:

    If the distribution of emissions is not substantially different
than under BART, and the alternative measure results in greater
emission reductions, then the alternative measure may be deemed to
achieve greater reasonable progress. If the distribution of
emissions is significantly different, the State must conduct
dispersion modeling to determine differences in visibility between
BART and the trading program for each impacted Class I area, for the
worst and best 20 percent of days. The modeling would demonstrate
``greater reasonable progress'' if both of the following two
criteria are met:
    (i) Visibility does not decline in any Class I area, and
    (ii) There is an overall improvement in visibility, determined
by comparing the average differences between BART and the
alternative over all affected Class I areas.\16\
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    \16\ 40 CFR 51.308(e)(3).

    The commenters noted that the EPA has consistently interpreted the
term ``distribution'' under the first test in 40 CFR 51.308(e)(3) (the
``emissions-reduction test'') to refer to geographic distribution.
Citing to prior EPA rulemaking actions, EDF stated that the ``EPA has
traditionally applied the modeling test only in cases where `the
distribution of emissions is significantly different' between BART and
the BART alternative.'' Earthjustice further asserted that, ``[w]hen
deciding which `Better than BART' test applies, the determinative
factor is whether the distribution of emissions between the alternative
and BART is substantially different.'' The commenters also noted that,
in our proposal to approve the Coronado BART Alternative, we again
interpreted ``distribution'' to refer to geographic distribution when
we proposed to determine that the Final Strategy would not result in a
substantially different distribution of emissions from BART. However,
the commenters suggested that, by proposing to approve ADEQ's use of
the two-prong modeling test, rather than the emissions-reduction test,
to evaluate the Interim Strategy, the EPA was

improperly applying a different interpretation of ``distribution'' to
the Interim Strategy.
    Earthjustice further asserted that the Coronado BART Alternative
``fails'' the emissions-reduction test, which it characterized as the
``correct'' test to apply in this instance. Citing the difference in
total NOX, SO2, and PM10 emissions for
each of the Interim Strategy scenarios compared with BART, Earthjustice
stated that each of the Interim Strategy options ``will result in
greater overall air pollution than BART for eight years after the
December 2017 BART compliance deadline.'' For this reason, the
commenter concluded that the Coronado BART Alternative is not ``Better
than BART'' and that the EPA should disapprove it.
    Response: We agree with the commenters that the EPA's long-standing
interpretation of 40 CFR 51.308(e)(3) is that, if the geographic
distribution of emissions is the same under the BART alternative and
BART, then the emissions distribution is not substantially
different.\17\ However, as explained further below, we do not agree
with the commenters that the distribution of emissions is a
determinative factor, such that if the distribution of emissions under
the BART alternative is not substantially different than under BART,
then the alternative must be evaluated using the emissions-reduction
test. We also do not agree that the EPA has previously interpreted 40
CFR 51.308(e)(3) to include such a requirement. Accordingly, contrary
to the commenters' assertions, we have not departed from our long-
standing interpretation in evaluating the Coronado SIP Revision.
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    \17\ As noted by the conservation organizations, the Ninth
Circuit recently upheld this interpretation as reasonable. Yazzie v.
EPA, 851 F.3d 960, 973 (9th Cir. 2017).
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    As an initial matter, we note that under 40 CFR 51.308(e)(2)(i)(E),
a SIP revision establishing a BART alternative must include a
determination under 40 CFR 51.308(e)(3) or otherwise based on the clear
weight of evidence that the alternative achieves greater reasonable
progress than BART. Thus, a state (or the EPA in promulgating a FIP)
always has the option to make a ``clear weight of evidence''
demonstration rather than choosing either of the two options under 40
CFR 51.308(e)(3).\18\
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    \18\ See WildEarth Guardians v. EPA, 770 F.3d 919, 935-37 (10th
Cir. 2014) (recognizing that a state may choose to make a
demonstration under 40 CFR 51.308(e)(3) or under a weight-of-
evidence approach).
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    If a state does elect to make a demonstration under 40 CFR
51.308(e)(3), the first test (the emissions-reductions test) provides
the option to make a demonstration without the need for dispersion
modeling when two conditions are satisfied: (1) ``the distribution of
emissions is not substantially different than under BART'' and (2)
``the alternative measure results in greater emission reductions.''
\19\ If the first condition is not satisfied (and the state has opted
to make a demonstration under 40 CFR 51.308(e)(3) rather than a weight-
of-evidence demonstration), then 40 CFR 51.308(e)(3) provides that the
state must make a demonstration under the two-prong modeling test.\20\
By contrast, 40 CFR 51.308(e)(3) does not indicate that a state must
apply the emissions-reduction test whenever the first condition of the
emissions-reduction test is satisfied. Thus, a state may choose to
apply the two-prong modeling test even if it determines that the first
condition of the emissions-reductions test is satisfied.
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    \19\ 40 CFR 51.308(e)(3).
    \20\ Id. (``If the distribution of emissions is significantly
different, the State must conduct dispersion modeling'' (emphasis
added)).
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    None of the examples of prior EPA actions cited by the commenters
indicate that the EPA has previously interpreted 40 CFR 51.308(e)(3) to
require use of the emissions-reduction test whenever the first
condition of that test is satisfied. Rather, the examples demonstrate
that states and the EPA have generally applied the emissions-reduction
test where both conditions of that test were clearly satisfied.\21\
However, in other instances, states and the EPA have made a weight-of-
evidence demonstration when the first condition of the emissions-
reduction test was satisfied, but it was not clear whether the second
condition was satisfied. For example, in 2015 we approved a weight-of-
evidence demonstration submitted by ADEQ for a BART alternative at the
Apache Generating Station (``Apache BART Alternative'').\22\ In that
case, all of the emissions were from a single facility, so the first
condition of the emissions-reduction test was satisfied. However, as
with the Coronado BART Alternative, the Apache BART Alternative was
expected to result in greater NOX emissions but lower
emissions of SO2 and PM10 compared with BART.\23\
We found that, ``[i]n this situation, where BART and the BART
Alternative result in reduced emissions of one pollutant but increased
emissions of another, it is not appropriate to use the `greater
emissions reductions' test under 40 CFR 51.308(e)(3).'' \24\ Similarly,
when evaluating a BART alternative for the Tesoro Refinery in
Anacortes, Washington, we determined that, even though all of the
emissions were from a single facility, modeling was needed ``to assess
whether the visibility improvement from the BART Alternative's
SO2 emission reductions would be greater than the visibility
improvement from the BART NOX reductions.'' \25\ Likewise,
when evaluating a proposed BART alternative for the Four Corners Power
Plant, the EPA considered the weight of evidence, including visibility
modeling, even though all emissions were from a single facility.\26\
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    \21\ This general trend is unsurprising, given that the
emissions-reduction test demands less time and effort as it does not
require modeling.
    \22\ 80 FR 19220 (April 10, 2015).
    \23\ Id. at 19221.
    \24\ 80 FR 19221.
    \25\ 78 FR 79344, 79355 (December 30, 2013).
    \26\ See 76 FR 10530, 10534 (February 25, 2011) (``EPA is
proposing to find, based on the weight of evidence, that [the
proposed alternative] will result in greater reasonable progress
towards the national visibility goal under section 169A(b)(2) than
EPA's October 19, 2010 BART proposal'' and 10537 (discussing
modeling results, even though the alternative could be deemed to
result in greater reasonable progress based on the emissions-
reduction test).
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    In evaluating the Coronado BART Alternative, we have followed our
long-standing interpretation of 40 CFR 51.308(e)(3) that, if the
geographic distribution of emissions is the same under the BART
alternative and BART, then the emissions distribution is not
substantially different. With regard to the Final Strategy, we found
that the distribution of emissions would not be substantially different
than under BART because all emissions under both scenarios were from
Coronado. Furthermore, under the Final Strategy, emissions of each
pollutant would be lower than or equal to BART, and the collective
emissions from the facility would be lower than BART.\27\ This allowed
us to use the emissions-reduction test to confirm that the Final
Strategy would ensure greater reasonable progress than BART.
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    \27\ As explained in our proposal, while the Final Strategy by
itself would not meet the requirements for a BART alternative, we
considered whether the Final Strategy would provide for ongoing
visibility improvement, as compared with BART, by evaluating whether
the Final Strategy meets both conditions of the emissions-reduction
test under 40 CFR 51.308(e)(3). 82 FR 19342.
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    In our proposal, we did not evaluate the Interim Strategy under the
emissions-reduction test because ADEQ did not make a demonstration
under this test. Therefore, we had no cause to consider whether the two
conditions of that test were satisfied. Nonetheless, in response to the
commenters' concerns,

we wish to clarify that the same interpretation of ``distribution of
emissions'' would apply to the Interim Strategy. Because all of the
emissions under the Interim Strategy and BART are from Coronado, the
distribution of emissions would not be substantially different under
the two scenarios, so the first condition of the test is satisfied.
Regarding the second condition of the emissions-reduction test, ADEQ
found that the Interim Strategy would result in greater NOX
emissions, but lower emissions of SO2 and PM10
compared with BART.\28\ Contrary to Earthjustice's suggestion, ADEQ did
not determine that the Interim Strategy ``fails'' the emissions-
reduction test. Rather, ADEQ found that the Interim Strategy would not
necessarily achieve greater emissions reductions than BART.\29\
Furthermore, while the commenters point to the difference in total
NOX, SO2, and PM10 emissions for each
of the Interim Strategy scenarios compared with BART, we do not
consider this comparison to be useful. As we explained in evaluating a
proposed BART alternative submitted by Utah:
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    \28\ 82 FR 19338.
    \29\ Coronado SIP Revision, Addendum page 4.

    We have not considered a total emissions profile that combines
emissions of multiple pollutants to determine whether BART or the
alternative is ``better,'' except where every visibility impairing
pollutant is reduced by a greater amount under the BART alternative.
A comparison of mass emissions from multiple pollutants (such as
NOX and SO2) is not generally informative,
particularly in assessing whether the alternative approach provides
for greater reasonable progress towards improving visibility.
Instead, when emissions of one or more pollutants increases under an
alternative, EPA has given the most weight to the visibility impacts
based on air quality modeling and used modeling to determine whether
or not a BART Alternative measure that relies on interpollutant
trading results in greater reasonable progress.\30\
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    \30\ 81 FR 2004, 2028 (January 14, 2016) (internal citations and
quotations omitted).

    Accordingly, we do not agree with the commenters that the Coronado
BART Alternative ``fails'' the emissions-reduction test. Rather, we
find that the emissions-reduction test is not the appropriate test to
evaluate the Interim Strategy of the Coronado BART Alternative, and it
was appropriate and reasonable for the State to apply the two-prong
modeling test to evaluate the Interim Strategy.
    Comment: Earthjustice argued that the Coronado BART Alternative
violates CAA section 110(l)'s anti-backsliding requirement because it
weakens the existing BART determination for Coronado. Quoting CAA
section 110(l) and citing several court cases interpreting that
provision, the commenter stated that section 110(l) ``prohibits plan
revisions that would interfere with an existing BART determination''
and that the ``EPA's common sense interpretation of section 110(l) is
that it prevents plan revisions that backslide or weaken an existing
Clean Air Act requirement by increasing overall air pollution or
causing worse air quality.'' The commenter asserted that the Coronado
BART Alternative weakens the existing BART determination for Coronado
because it would result in increased air pollution and cause worse
visibility impairment at multiple Class I areas in the years 2018
through 2025 and therefore violates section 110(l).
    The commenter further argued that the EPA improperly based our
110(l) analysis on our determination that the Coronado BART Alternative
would result in greater reasonable progress than BART. The commenter
re-asserted its claim that the Coronado BART Alternative is not
``Better than BART'' because it ``fails'' the emissions-reduction test.
Earthjustice also argued that, ``[b]ecause the purposes of a BART
alternative and section 110(l) are distinct and a BART alternative may
perform worse than BART in some respects, it is unreasonable to use the
`Better than BART' test as the sole criterion for whether an
alternative complies with section 110(l).''
    Earthjustice further noted that ADEQ was not choosing between BART
and a BART alternative for Coronado in the first instance, but was
instead replacing an existing BART determination that had been fully
litigated and in place for four and a half years. They argued that,
under these circumstances, section 110(l) requires the EPA to
independently determine whether the alternative weakens the existing
BART determination, and the EPA cannot rely on the ``Better than BART''
test as the sole criterion for whether an alternative complies with
section 110(l).
    Finally, the commenter made several points related to the EPA's
approval of a SIP revision that established a new BART determination
for Cholla Generating Station (``Cholla BART Reassessment''). Noting
certain similarities between the Coronado BART Alternative and the
Cholla BART Reassessment, the commenter argued that the EPA had
improperly ``applied a completely different rationale and analysis when
determining whether the two BART revisions complied with section 110(l)
for regional haze purposes.'' The commenter also criticized the EPA's
responses to comments on section 110(l) issues related to the Cholla
BART Reassessment and asserted that the EPA ``should not attempt to
justify the Coronado BART alternative on similar grounds.'' In
particular, the commenter asserted that the EPA had (1) conflated its
section 110(l) analysis regarding NAAQS attainment with its section
110(l) analysis regarding Cholla's existing regional haze requirements,
(2) unreasonably dismissed the relevant section 110(l) case law, and
(3) incorrectly relied, in part, on post-2025 emissions reductions from
Cholla to justify why the plan complied with section 110(l).
    Response: We do not agree that the Coronado SIP Revision violates
CAA section 110(l). As explained further below, the commenter has
mischaracterized the requirements of section 110(l) and the EPA's
interpretation of those requirements. Neither the statutory language
nor the case law cited by the commenter support the commenter's
interpretation that a SIP revision that allows for additional air
emissions or less stringent requirements than the existing plan per se
constitutes a violation of CAA section 110(l).
    Section 110(l) prohibits the EPA from approving a SIP revision ``if
the revision would interfere with any applicable requirement concerning
attainment and reasonable further progress (as defined in [CAA section
171]), or any other applicable requirement of [the CAA].'' \31\ This
language does not prohibit the EPA from approving any SIP revision that
weakens the existing plan's requirements or allows for an increase in
emissions of a particular pollutant, nor has the EPA interpreted
section 110(l) in this manner. The EPA's evaluation of whether a
noninterference determination can be made under section 110(l) is a
case-by-case assessment based on the specific facts and circumstances
at issue. The commenter has selectively quoted from the EPA's prior
actions and court cases concerning those actions in order to support
their position. In particular, the commenter asserts that, ``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.' '' However, the context for the quote makes
clear that the EPA was not referring to a blanket prohibition on
increases in emissions. Rather, we were

describing our interpretation of section 110(l) as applied to a SIP
revision that substituted emissions reductions to make up for increased
emissions resulting from moving an existing control measure to a
contingency measure. We determined that we could approve this change
without requiring an attainment demonstration, explaining that:
---------------------------------------------------------------------------

    \31\ 42 U.S.C. 7410(l).

    Prior to the time when the control strategy SIP revisions are
due, to demonstrate no [interference] with any applicable NAAQS or
requirement of the Clean Air Act under section 110(l), EPA has
interpreted this section such that States can substitute equivalent
(or greater) emissions reductions to compensate for the control
measure being moved from the regulatory portion to the contingency
provisions. As long as actual emissions in the air are not
increased, EPA believes that equivalent (or greater) emissions
reductions will be acceptable to demonstrate non-interference.\32\
---------------------------------------------------------------------------

    \32\ 70 FR 28429, 28430 (May 18, 2005) (emphasis added).

    Thus, in the circumstances presented in that case, we found that,
rather than submit a new attainment demonstration, the state could
instead substitute one measure for another with equivalent or greater
emissions reductions/air quality benefit in order to demonstrate
noninterference with attainment, maintenance, and reasonable further
progress (RFP) requirements. However, the EPA has never indicated that
such a substitution approach is required in all cases. In some cases,
states can provide an air quality analysis, typically based on
modeling, showing that removing a particular control measure will not
interfere with attainment, maintenance, or RFP requirements.\33\
Additionally, a modeling-based demonstration of non-interference with
these requirements may be possible where increases in one pollutant are
offset by decreases in another pollutant and the modeling analysis
shows that the decreases will provide at least equivalent air quality
benefits for each affected NAAQS.\34\
---------------------------------------------------------------------------

    \33\ See ``Demonstrating Noninterference Under Section 110(l) of
the Clean Air Act When Revising a State Implementation Plan,'' 6,
10-11 (June 8, 2005) (Draft Guidance).
    \34\ Id. at 8.
---------------------------------------------------------------------------

    The cases cited by the commenter also fail to support the
commenter's interpretation. In Kentucky Resources Council, the court
upheld the EPA's decision that a new attainment demonstration was not
required in order to show that the SIP revision would not interfere
pursuant to section 110(l).\35\ Thus, the examination of whether the
SIP revision would ``worsen air quality'' was based on whether the
area, which was designated as a nonattainment area for the relevant
NAAQS, would have more difficulty in attaining and maintaining the
NAAQS with the SIP revision--not, as the commenter argues here, whether
the SIP revision would simply result in increased emissions. Similarly,
the Ala. Envtl. Council v. EPA \36\ and Indiana v. EPA \37\ courts
upheld the EPA's interpretation that section 110(l) allows for a
substitution approach to demonstrate non-interference with the Act's
requirements, but did not hold that an increase in emissions per se
constituted a violation of section 110(l).
---------------------------------------------------------------------------

    \35\ 467 F.3d 986, 996 (6th Cir. 2006).
    \36\ 711 F.3d 1277, 1293 (11th Cir. 2013).
    \37\ 796 F.3d 803, 812 (7th Cir. 2015).
---------------------------------------------------------------------------

    A fourth case cited by the commenter, Hall v. EPA,\38\ concerned
the EPA's analysis of non-interference with attainment requirements in
a nonattainment area and did not address the Act's other requirements
(including visibility protection requirements) or how those
requirements apply in attainment areas.\39\ Thus, the case is not
relevant to the commenters' objections, which specifically concern
visibility protection requirements.\40\
---------------------------------------------------------------------------

    \38\ 273 F.3d 1146 (9th Cir. 2001).
    \39\ Id. at 1160, n.11 (``Our assessment of the EPA's reasoning
does not apply to review of rules governing areas that are in
attainment.'').
    \40\ See Earthjustice comment letter at 22 (``[T]he Conservation
Organizations take no issue with EPA's finding that the alternative
does not interfere with attainment of the applicable NAAQS.'').
---------------------------------------------------------------------------

    Two additional cases cited by the commenter concerned regional haze
SIP actions, but do not support the commenter's contention that ``after
EPA approves a BART determination (or other regional haze requirement),
the agency cannot later modify the BART determination in a manner that
weakens it.'' \41\ WildEarth Guardians v. EPA \42\ involved a challenge
to a regional haze plan under section 110(l)'s requirements concerning
noninterference with attainment and maintenance, which the commenter
acknowledges are not of concern in relation to the Coronado SIP
Revision.\43\ In that case, the court found that the petitioner had
identified nothing in the SIP revision at issue ``that weakens or
removes any pollution controls.'' \44\ Contrary to the commenter's
assertion, the court did not suggest that, if the petitioner had
identified such a provision, it would necessarily have constituted a
violation of section 110(l). In fact, the court declined to decide if
section 110(l) even applied to the plan in question, stating only in
dicta that, ``even if the SIP merely maintained the status quo, that
would not interfere with the attainment or maintenance of the NAAQS.''
\45\
---------------------------------------------------------------------------

    \41\ Id. at 20.
    \42\ 759 F.3d 1064 (9th Cir. 2014).
    \43\ See Earthjustice comment letter at 22 (``[T]he Conservation
Organizations take no issue with EPA's finding that the alternative
does not interfere with attainment of the applicable NAAQS.'').
    \44\ WildEarth Guardians, 759 F.3d at 1074.
    \45\ Id.
---------------------------------------------------------------------------

    Oklahoma v. EPA \46\ affirmed the EPA's authority to review state
BART determinations, based on, among other things, section 110(l).
However, contrary to the commenter's suggestion, the Oklahoma court did
not indicate that individual BART determinations themselves are
``applicable requirements'' for purposes of section 110(l). Rather, the
court found that the underlying statutory requirements concerning
visibility protection constitute ``applicable requirements.'' \47\
Accordingly, it is these generally applicable statutory requirements
for which a demonstration of non-interference is required.
---------------------------------------------------------------------------

    \46\ 723 F.3d 1201, 1204, 1207 (10th Cir. 2013).
    \47\ The court specifically noted that the visibility protection
provisions of CAA section 169A and 169B are ``applicable
requirements'' for purposes of CAA section 110(a)(2)(J). We agree
with the commenter that these requirements are also ``applicable
requirements'' for purposes of section 110(l).
---------------------------------------------------------------------------

    In this instance, the critical statutory requirement is that the
applicable implementation plan ``contain such emission limits,
schedules of compliance and other measures as may be necessary to make
reasonable progress toward meeting the national goal'' of preventing
any future and remedying any existing visibility impairment in Class I
areas due to manmade air pollution.\48\ While measures for achieving
``reasonable progress'' generally include requirements for source-
specific BART determinations,\49\ the EPA has long interpreted CAA
section 169A(b)(2) to allow for the adoption of ``implementation plan
provisions other than those provided by BART analyses in situations
where the agency reasonably concludes that more `reasonable progress'
will thereby be attained'' because `` `reasonable progress' is the
overarching requirement that implementation plan revisions under 42
U.S.C. 7491(b)(2) must address.'' \50\ This interpretation has been
upheld by both the Ninth Circuit \51\ and the D.C. Circuit \52\ and is
reflected in the

``Better than BART'' provisions of the Regional Haze Rule that apply to
the Coronado SIP Revision.\53\ Accordingly, in evaluating the Coronado
SIP Revision under section 110(l) with respect to the Act's visibility
protection requirements, the relevant question is not whether it would
interfere with the BART determination in our FIP, but whether it would
interfere with the overall statutory requirement for reasonable
progress, as implemented through the ``Better than BART'' provisions of
the Regional Haze Rule. For the reasons explained in our proposal and
elsewhere in this document, we have determined that the Coronado SIP
Revision satisfies the ``Better than BART'' requirements of the
Regional Haze Rule, meaning that it will result in greater reasonable
progress than the existing BART requirements for Coronado. Therefore,
the Coronado SIP Revision complies with the Act's reasonable progress
requirements. As such, we do not agree with the commenter that we must
apply some separate criterion to determine whether the Coronado SIP
Revision would interfere with those same requirements.
---------------------------------------------------------------------------

    \48\ CAA section 169A(b)(2), 42 U.S.C. 7491(b)(2).
    \49\ CAA section 169A(b)(2)(A), 42 U.S.C. 7491(b)(2)(A).
    \50\ Central Arizona Water Conservation District v. EPA, 990
F.2d 1531, 1543 (9th Cir. 1993).
    \51\ Id.
    \52\ Center for Energy and Economic Development v. EPA, 398 F.3d
653, 660 (D.C. Cir. 2005); Utility Air Regulatory Group v. EPA, 471
F.3d 1333, 1340-41 (D.C. Cir. 2006).
    \53\ 40 CFR 51.308(e)(2)-(6). See also Central Arizona Water
Conservation District, 990 F.2d at 1543; Center for Energy and
Economic Development, 398 F.3d at 660; Utility Air Regulatory Group,
471 F.3d at 1340-41 (upholding the ``better-than-BART'' provisions).
---------------------------------------------------------------------------

    Furthermore, even if such a separate evaluation were necessary, we
believe that the modeling performed to support ADEQ's demonstration of
greater reasonable progress for the Interim Strategy is adequate to
demonstrate non-interference with the Act's visibility protection
provisions.\54\ As noted above, we interpret section 110(l) to allow
for a modeling-based demonstration of non-interference with attainment,
maintenance, and RFP requirements where increases in one pollutant are
offset by decreases in another pollutant and the modeling analysis
shows that the decreases will provide at least equivalent air quality
benefits for each affected NAAQS.\55\ Similarly, such a modeling
demonstration is appropriate to demonstrate non-interference with
visibility protection requirements when reductions of one or more
pollutants (in the case of the Interim Strategy, SO2 and PM)
are being substituted for reductions of another pollutant (in the case
of the Interim Strategy, NOX). As described in our proposal
and elsewhere in this document, the modeling submitted with the
Coronado SIP Revision demonstrates that the Interim Strategy will
result in improved visibility at all affected Class I areas compared
with 2014 Baseline Emissions (prong 1) and will result in improved
visibility, on average, across all Class I areas, compared with BART on
both the 20% best and worst days (prong 2).\56\ As the commenter noted,
the modeling indicates that visibility improvement at certain Class I
areas will be slightly less under the Interim Strategy as compared with
BART between 2018 and 2025. However, we do not believe that a temporary
decrease in the rate of improvement at these areas constitutes
``interference'' with the Act's visibility protection requirements,
given that it is accompanied by a greater improvement at other Class I
areas. As the D.C. Circuit has explained, ``nothing in [CAA] Sec.
169A(b)'s `reasonable progress' language requires at least as much
improvement at each and every individual area as BART itself would
achieve (much less improvement at each area at every instant) . . . .''
\57\ Furthermore, once the Final Strategy is implemented by 2026, we
anticipated that there will be greater improvement across all Class I
areas compared to BART.\58\ Therefore, we conclude that the Coronado
SIP Revision will not interfere with the CAA's visibility protection
requirements.
---------------------------------------------------------------------------

    \54\ The commenter does not appear to object to our
determination that implementation of the Final Strategy would
clearly satisfy section 110(l) because it would result in overall
greater emissions reductions compared to the BART Control Strategy.
    \55\ Draft Guidance at 8.
    \56\ See 82 FR 19338-19341.
    \57\ Utility Air Regulatory Group, 471 F.3d at 1340-41.
    \58\ We do not agree with the commenter that it is inappropriate
to consider post-2025 emissions reductions under section 110(l),
given that such reductions will help to ensure continued compliance
with the Act's reasonable progress requirements.
---------------------------------------------------------------------------

    The commenters' statements regarding the Cholla BART Reassessment
are out of the scope of today's action. That action was a separate
analysis based on the facts and circumstances of that SIP revision,
which we finalized on March 17, 2017. We also do not agree with the
commenter that we improperly applied a different rationale and analysis
when determining whether the Coronado BART Alternative and the Cholla
BART Reassessment complied with section 110(l). In both cases, we
considered whether the relevant SIP revision would interfere with the
applicable statutory requirements.\59\ However, despite some
similarities between the two SIP revisions, they are not subject to all
the same statutory requirements, so the respective section 110(l)
analyses necessarily differ in some respects. In particular, because
the Cholla BART Reassessment was a BART determination, we considered
whether it met the CAA's BART requirements, as well as whether it was
consistent with the CAA's long-term national goal of restoring natural
visibility conditions at Class I areas.\60\ Because the CAA's BART
requirements do not apply to a BART alternative,\61\ we did not
consider them in reviewing the Coronado SIP Revision under section
110(l). Rather, as explained above, we have considered whether the
Coronado SIP Revision is consistent with the CAA requirement for
reasonable progress toward the long-term national goal.
---------------------------------------------------------------------------

    \59\ 81 FR 46862; 82 FR 15150.
    \60\ Id.
    \61\ See, e.g., Yazzie, 851 F.3d at 969 (affirming that
statutory deadline for BART does not apply to a BART alternative).
---------------------------------------------------------------------------

    Finally, while we do not agree that our responses to comments
concerning the Cholla BART Reassessment were mistaken, those responses
are not at issue in this action. To the extent that the commenter's
concerns are relevant to the Coronado SIP Revision, we have addressed
them above.
    Comment: Earthjustice and EDF both raised concerns with the CAMx
modeling relied upon by ADEQ and the EPA to determine that the Interim
Strategy would result in greater reasonable progress than BART. They
noted that, although ADEQ had performed additional analyses to
determine if the modeled visibility changes could be attributed to
emissions changes rather than model ``noise,'' the results were ``still
applicable to only one year's meteorological transport pattern.'' They
asserted that the EPA should require a demonstration that the emissions
curtailments would result in better visibility conditions across varied
air transport conditions.
    EDF acknowledged that the EPA's modeling guidance allows the use of
a single year of meteorological data for modeling of regional scale
pollutants using CAMx. However, the commenters noted that the CAMx
modeling for the Coronado BART Alternative focused on a single source's
impacts on very specific geographic locations that ``would have large
variations due to yearly meteorological changes in wind transport
patterns.'' Earthjustice stated that most BART determinations and all
BART alternatives that it was aware of relied on CALPUFF modeling. EDF
and Earthjustice also noted that, where the EPA had previously used
CAMx modeling for BART determinations, it was in conjunction with
CALPUFF modeling, which typically uses at least a three-year
meteorological database.

They asserted that, in light of the small changes in visibility between
the modeled emissions scenarios, ``the difference in impacts that
delineate one alternative curtailment period from another are within
the margin of error for the model output.'' They also stated that, if
the difference were consistent from year to year, ``it would provide
more confidence in the resulting implementation of multiple curtailment
periods.'' Earthjustice added that ``the demonstration provided by ADEQ
only gives information about the relative performance of BART versus
the alternative if the 2008 meteorological conditions are duplicated in
every future year.''
    Response: We acknowledge the commenters' concern about the
robustness of a modeling analysis based on a single year of
meteorology, given the year-to-year variability of meteorological
conditions and their possible effect on visibility impacts. However,
the Regional Haze Rule does not require modeling of a longer period to
make a demonstration under the two-prong test, and EPA guidance also
does not recommend a longer period. Rather, to address a range of
meteorological conditions, the EPA's photochemical modeling guidance
recommends modeling a full year. Our current guidance states that ``the
preferred approach for regional haze-related model applications is to
simulate an entire, representative year.'' \62\ More recent draft
guidance states:
---------------------------------------------------------------------------

    \62\ Guidance on the Use of Models and Other Analyses for
Demonstrating Attainment of Air Quality Goals for Ozone,
PM2.5, and Regional Haze, EPA-454/B-07-002 (April 2007)
p. 149.

    Regional Haze--Choose time periods which reflect the variety of
meteorological conditions which represent visibility impairment on
the 20% best and 20% worst days in the Class I areas being modeled
(high and low concentrations necessary). This is best accomplished
by modeling a full year.\63\
---------------------------------------------------------------------------

    \63\ Modeling Guidance for Demonstrating Attainment of Air
Quality Goals for Ozone, PM2.5, and Regional Haze, 17
(December 2014) (draft).

    Thus, modeling a full year with a photochemical model to represent
visibility impairment on the 20% best and worst days is consistent with
EPA guidance.
    We also note that states and the EPA rarely, if ever, model more
than a single year with a photochemical model even for NAAQS attainment
demonstrations covering large urban areas with thousands of sources
possibly subject to emission controls. A key reason for the practice
and recommendation of modeling just a single year is the time and
expense involved in running the computationally-intensive computer
model and in preparing meteorological and emissions inputs. The
emission inventory requires economic variables and population estimates
for the whole area covered in the model domain, as well as the
emissions calculations for the many sources of pollution in the domain.
Meteorological and other model input parameters typically must be
adjusted in an iterative process to ensure the model performs
adequately. The model's performance must then be evaluated. All of
these tasks must be done separately for each year. Thus, while modeling
longer periods may improve the robustness of the modeling results, it
also requires significant additional time and resources. Therefore, it
is prudent to assess whether the benefits of the modeling justify the
additional effort for each individual application. Given that the
modeling for the Coronado SIP Revision affects only a single source for
a limited period of time (i.e., the period of the Interim Strategy), we
do not think it is reasonable to require more than a single year of
photochemical modeling.
    We note that the situation was different for the CALPUFF modeling
that states and the EPA conducted for BART determinations, for which
the EPA recommended that at least three years of meteorological data be
used.\64\ Under the BART Guidelines, CALPUFF could be used for
assessing the visibility impacts of a single source without the process
of input adjustment and performance evaluation described above for
photochemical models.\65\ Furthermore, the emission inventory for BART
modeling was a single source, rather than the thousands of sources
needed in a photochemical model such as CAMx. The meteorological inputs
to CALPUFF are also simpler than for a photochemical model, and they
were developed by multistate Regional Planning Organizations, such as
the Western Regional Air Partnership (WRAP), for use in BART
determinations for numerous different facilities. In summary, while the
CALPUFF modeling used for BART determinations employed multiple years
of meteorology, the cost and effort involved was lower than for CAMx,
and it was spread over multiple states and sources. By contrast, the
Interim Strategy in the Coronado SIP Revision affects only a single
source for a limited period of time. Accordingly, we find that modeling
multiple years with CAMx for the two-prong test applied to the Interim
Strategy would constitute a disproportionately high level of effort
relative to the modest benefit of such an approach.
---------------------------------------------------------------------------

    \64\ See 70 FR 39107-39108 (``For assessing the fifth factor,
the degree of improvement in visibility from various BART control
options, the States may run CALPUFF or another appropriate
dispersion model to predict visibility impacts . . . The maximum 24-
hour emission rates would be modeled for a period of three or five
years of meteorological data.'').
    \65\ See, e.g., BART Guidelines, 40 CFR part 51, appendix Y,
section IV.D.5. (``Use CALPUFF or other appropriate dispersion model
to determine the visibility improvement expected at a Class I area
from the potential BART control technology applied to the source'');
70 FR 39123 (``For the specific purposes of the regional haze rule's
BART provisions . . . we have concluded that CALPUFF is sufficiently
reliable to inform the decision-making process.'').
---------------------------------------------------------------------------

    Regarding the specific year chosen for modeling the Interim
Strategy, as discussed in connection with SRP's comments and the
analysis submitted by Ramboll Environ,\66\ we find that the 2008
meteorology year was adequately representative for the two-prong test.
In addition, as explained further below, that analysis presented
evidence that 2008 was a conservative year, in that the Interim
Strategy would be expected to show a greater benefit compared to the
baseline and BART in other years.
---------------------------------------------------------------------------

    \66\ ``Additional Documentation on the Coronado Generating
Station Better-than-BART Modeling Analysis to Address EPA's October
2016 Request'', Memorandum from Lynsey Parker and Ralph Morris,
Ramboll Environ to Bill McClellan, Salt River Project (April 6,
2017).
---------------------------------------------------------------------------

    Comment: Earthjustice and EDF expressed concern about the use of a
projected 2020 inventory rather than clean conditions or the inventory
of a ``known year'' for the CAMx modeling. Earthjustice asserted that,
``[t]o the extent EPA considers 2020 to be more representative of
future or cleaner air quality conditions, CAMx should instead have been
run with only single source emissions plus nonanthropogenic emissions
to simulate reaction chemistry under natural conditions.'' They argued
that the EPA must include CALPUFF modeling to help support the
conclusion that the Coronado BART Alternative is in fact better than
BART ``when looking at source impacts compared with natural
conditions.''
    Response: We do not agree that ADEQ should have used natural
conditions or the inventory of a ``known'' (i.e., past) year to
evaluate the Interim Strategy. The Regional Haze Rule does not identify
which background conditions states must use for evaluating greater
reasonable progress under the two-prong test in 40 CFR 51.308(e)(3).
However, in the preamble to the final rule promulgating the two-prong
test, we explained that:

    The underlying purpose of both prongs of the test is to assess
whether visibility conditions at Class I areas would be better

with the alternative program in place than they would without it. .
. . In both cases, the logical reference point is visibility
conditions as they are expected to be at the time of program
implementation but in the absence of the program.'' \67\
---------------------------------------------------------------------------

    \67\ 70 FR 39104, 39138 (July 6, 2005).

    In other words, the projected conditions at the time the BART
alternative will be implemented, including emissions from all other
sources, but assuming that no emission reductions from BART or the BART
alternative have yet occurred, are an appropriate background for
modeling under the two-prong test. Here, the Interim Strategy will be
implemented between 2018 and 2025, so ADEQ's decision to use the 2020
emissions inventory as the background conditions for comparing the
Interim Strategy to BART was reasonable.
    We also do not believe that it is necessary to conduct CALPUFF
modeling to support the conclusion that the Coronado BART Alternative
would result in greater reasonable progress than BART. While ADEQ could
have elected to conduct CALPUFF modeling to make a demonstration of
greater reasonable progress, it instead chose to use CAMx modeling to
make this demonstration. As explained in our proposal:

    CAMx has a scientifically current treatment of chemistry to
simulate the transformation of emissions into visibility-impairing
particles of species such as ammonium nitrate and ammonium sulfate,
and is often employed in large-scale modeling when many sources of
pollution and/or long transport distances are involved.
Photochemical grid models like CAMx include all emissions sources
and have realistic representations of formation, transport, and
removal processes of the particulate matter that causes visibility
degradation.\68\
---------------------------------------------------------------------------

    \68\ 82 FR 19338-19339.

    Because it incorporates the many emissions sources that create the
background conditions at the time the BART alternative will be
implemented, CAMx is well suited for modeling under the two-prong
test.\69\ Furthermore, as a result of recent developments in modeling
techniques,\70\ the EPA and states have begun to use photochemical
models such as CAMx to assess the visibility impacts from individual
sources such as Coronado.\71\ Thus, ADEQ appropriately relied on CAMx
modeling to assess the Coronado BART Alternative under the two-prong
modeling test.
---------------------------------------------------------------------------

    \69\ As explained in response to comments above, it was
appropriate and reasonable for the State to apply the two-prong
modeling test to the Coronado BART Alternative.
    \70\ See, e.g., 82 FR 5182, 5196 (``Source sensitivity and
apportionment techniques implemented in photochemical grid models
have evolved sufficiently and provide the opportunity for estimating
potential visibility and deposition impacts from one or a small
group of emission sources using a full science photochemical grid
model.'').
    \71\ See, e.g., 81 FR 296, 327-28 (January 5, 2016) (describing
the use of CAMx for evaluating visibility impacts of sources in a
Texas Regional Haze FIP).
---------------------------------------------------------------------------

    Comment: Earthjustice and EDF objected to the fact that the CAMx
modeling used to assess the Coronado BART Alternative was limited to a
range of 300 kilometers (km), given that the EPA has previously used
CAMx to assess impacts beyond the 300 km range. EDF stated that the EPA
should explain why the 300 km limit was appropriate. Earthjustice
argued that the EPA should include modeling results for Class I areas
outside of 300 km.
    Response: We agree with the commenters that there is no a priori
reason to limit the modeling under the two-prong test to Class I areas
within 300 km.\72\ We nevertheless find that the set of Class I areas
evaluated in the CAMx modeling is adequately representative in this
instance. The 300 km radius used in the modeling covers a large region,
a range of geographic settings, and a full range of compass directions
from Coronado. In addition, the visibility impacts of Coronado's
emissions generally decline with distance.\73\ Because of that, when
comparing projected visibility conditions under the BART Alternative
scenario to projected visibility conditions under the baseline
scenario, the differences between the two scenarios generally decline
with distance. The same is true when comparing the BART Alternative to
BART. As a result, while including more distant areas would have a
small effect on the numerical values used in the two-prong test, doing
so would be unlikely to change the outcome of the test.
---------------------------------------------------------------------------

    \72\ Neither the Regional Haze Rule nor EPA guidance define
``affected'' Class I areas for purposes of the two-prong test.
    \73\ This is illustrated in the graphic ``Coronado CAMx Baseline
Impacts--Baseline delta DV Impact vs. km distance,'' in the file
titled ``Coronado_baseline_CAMx_ddv_vs_distance.pdf,'' available in
the docket for this action.
---------------------------------------------------------------------------

    Comment: SRP commented that it strongly supports the EPA's:
     Proposed approval of ADEQ's demonstration under 40 CFR
51.308(e)(3) that the Coronado BART Alternative Interim Strategy will
achieve greater reasonable progress than BART at Coronado;
     proposed approval of the CAMx modeling used by ADEQ;
     determination that the Coronado BART Alternative Final
Strategy will result in greater emission reductions than BART for
Coronado; and
     determination that the Final Strategy and its associated
emission reductions are not necessary to demonstrate that the Coronado
BART Alternative will achieve greater reasonable progress than BART
during the period of the first long-term strategy.
    Response: We acknowledge the comments.
    Comment: SRP urged the EPA to note the assessment that ADEQ
conducted that shows the importance of SO2 (and resulting
sulfate) reductions in improving visibility in Class I areas
potentially affected by Coronado. In particular, SRP asserted that:

    ADEQ demonstrated that SO2 emission reductions, such
as those that would occur under the [Coronado] BART Alternative, are
very significant in light of the facts that ``the SO2-
attributed visibility extinction is generally more than three times
the NOX-attributed visibility extinction'' and that, in
particular, ``the ratios of SO2-attributed visibility
extinction to NOX-attributed visibility extinction
averaged over all Class I areas are 3.7, 4.2 and 4.2 for the 20%
best days, the 20% worst days, and all days, respectively.''

    Response: As noted in footnote 31 of our proposal,\74\ ADEQ's
``Supplemental Analysis of IMPROVE Monitoring Data'' is not directly
relevant to the State's demonstration of greater reasonable progress
under the two-prong test in 40 CFR 51.308(e)(3), so we did not consider
it in evaluating the State's demonstration. The results of the CAMx
modeling establish that, through a combination of controls, emission
reductions, atmospheric chemistry, and meteorology, the Coronado BART
Alternative will result in greater reasonable progress than BART, as
required under 40 CFR 51.308(e)(3).
---------------------------------------------------------------------------

    \74\ See 82 FR 19338, dated April, 27, 2017; footnote 31.
---------------------------------------------------------------------------

    Comment: SRP stated that, while the Coronado BART Alternative was
proposed to be approved under 40 CFR 51.308(e)(3), it is also
approvable under 40 CFR 51.308(e)(2)(i)(E) under the weight-of-evidence
test. SRP further noted that ``[t]he clear weight of evidence test
allows states to take into consideration a wide range of factors,
visibility metrics, or other relevant considerations in making a
better-than-BART determination.''
    Response: The EPA acknowledges the comment.
    Comment: SRP noted that the EPA described the Interim Strategy as
``in effect from December 5, 2017 to

December 31, 2025,'' and indicated that the Final Strategy ``would take
effect on January 1, 2026.'' The commenter stated that, ``the December
31, 2025, date represents a deadline for SRP to install and operate an
SCR on Unit 1 or close Unit 1, rather than the conclusion of the
effective period for the Interim Strategy'' and requested that the EPA
clarify that the installation and operation of the SCR on Unit 1 or
closure of Unit 1 will occur no later than December 31, 2025, and that
the Interim Strategy will be in effect until the installation of SCR on
Unit 1 or closure of Unit 1.
    Response: We agree with the commenter that the installation and
operation of the SCR on Unit 1 or closure of Unit 1 must occur no later
than December 31, 2025, and that the Interim Strategy will be in effect
until the installation of SCR on Unit 1 or closure of Unit 1. We have
made this clarification in this final notice.
    Comment: SRP noted that the EPA described the SO2
emission cap as ``plant-wide'' and ``facility-wide.'' The commenter
recommended that the EPA ``clarify that the 1,970 tpy SO2
emission cap applies to the aggregate annual emissions from Unit 1 and
Unit 2 only and does not apply to any emissions from any other sources
at the site.'' The commenter also noted that, ``[i]n the event that
Unit 1 shuts down, the SO2-emission tonnage limit applicable
after the shutdown of that unit is 1,080 tons per calendar year.''
    Response: We agree with the commenter that the 1,970 tpy
SO2 emission cap applies to the aggregate emissions from
Unit 1 and Unit 2, and that, if Unit 1 shuts down, an SO2
emission cap of 1,080 tpy would apply to Unit 2. We have made this
clarification in this final notice.
    Comment: SRP asserted that the EPA incorrectly stated that ``the
Coronado SIP Revision will require equivalent or lower emissions of
NOX, PM and SO2 for all future years, compared to
the emission levels currently allowed under the applicable
implementation plan (including both the Arizona Regional Haze SIP and
the Arizona Regional Haze FIP).'' The commenter noted that the Interim
Strategy requires fewer NOX reductions than the Arizona
Regional Haze FIP.
    Response: We agree with SRP that the Interim Strategy requires
fewer NOX reductions than the Arizona Regional Haze FIP
between December 5, 2017, and December 31, 2025. However, the statement
from our proposal quoted by the commenter refers to ``the emission
levels currently allowed under the applicable implementation plan.''
\75\ Because the compliance date for the NOX emission limits
in the Arizona Regional Haze FIP is December 5, 2017, the applicable
implementation plan does not currently limit NOX emissions
from Coronado. Thus, as correctly noted in our proposal, the Coronado
SIP Revision will require lower emissions of NOX, PM and
SO2 for all future years, compared to the emission levels
currently allowed under the applicable implementation plan.
---------------------------------------------------------------------------

    \75\ 82 FR 19344 (emphasis added).
---------------------------------------------------------------------------

    Comment: SRP included as an attachment to its comments a technical
memorandum from Ramboll Environ that evaluated whether the CAMx
modeling results for the two-prong test were influenced by numerical
noise, based on a spatial and numerical analysis of CAMx model outputs
for visibility and its sulfate and nitrate components.\76\ The
components reflect the differences in SO2 and
NOX, respectively, between BART and the Interim Strategy.
The differences showed a spatial pattern consistent with realistic
gradual variation in the atmosphere, rather than random variation as
would be expected from numerical noise. Therefore, the memorandum
concluded that the modeled numerical differences represent real
visibility improvements and are not just numerical artifacts.
---------------------------------------------------------------------------

    \76\ Memorandum from Lynsey Parker and Ralph Morris, Ramboll
Environ (September 22, 2016).
---------------------------------------------------------------------------

    Response: This same analysis was included in the Coronado SIP
Revision and evaluated for our proposal. We reaffirm our finding that
the analysis supports the conclusion that the two-prong test results
indicate actual visibility improvement under the Interim Strategy
compared to BART and no degradation relative to the baseline.\77\
---------------------------------------------------------------------------

    \77\ 82 FR 19341.
---------------------------------------------------------------------------

    Comment: SRP included as an attachment to its comments a second
memorandum from Ramboll Environ analyzing (1) whether the meteorology
from the year that was used for modeling (2008) was adequately
representative of other years and (2) whether, extending the length of
the curtailment periods under the Interim Strategy would give
additional visibility benefits.
    The first of three Ramboll Environ analyses of the
representativeness of 2008 was a comparison of 2008 temperatures and
precipitation to typical conditions based on more than 100 years of
meteorological data. The memorandum noted that temperature affects the
oxidizing potential of the atmosphere, which in turn affects the
conversion of SO2 and NOX emissions into
visibility-impairing sulfates and nitrates. Ramboll Environ found that
2008 was somewhat warmer than the average, but that generally the
temperature was well within the normal range of variation. The
memorandum also noted that precipitation can remove visibility-
impairing pollutants from the atmosphere and found that 2008
precipitation was classified as ``Near Normal.'' Accordingly, Ramboll
Environ concluded that 2008 was reasonably representative for purposes
of the visibility modeling.
    In a second analysis, Ramboll Environ examined visibility-impairing
ammonium sulfate and ammonium nitrate concentrations during 2000-2012
as measured at four Class I areas in different compass directions from
Coronado. These are shown as time series bar or line graphs for the
various pollutants and areas. Ramboll Environ found that the annual
averages for 2008 were near the middle of the averages for the
individual years from 2000-2012. Monthly averages for 2008 were also
consistent with the overall range seen from 2000-2012. Compared to
other years, monthly sulfate averages for 2008 tended to be on the high
side during March, April, and September, and on the low side in mid-
summer and in December through February, but nevertheless consistent
with the overall range seen for 2000-2012. Ramboll Environ concluded
that, because the curtailment periods for Interim Strategy options IS3
and IS4 \78\ are from November 21 through January 21, overlapping the
period for which 2008 tended to have lower sulfate, the modeled
visibility improvement for these options would also tend to be lower
than would be expected for other years. That is, the actual visibility
benefits of these options would generally be expected to be larger than
the modeling results indicate. The same conclusion applies to nitrate,
for which 2008 monthly averages tend to be on the low side, compared to
the averages for 2000-2012 years during the months that include the
curtailment periods (November, December, and January).
---------------------------------------------------------------------------

    \78\ The memorandum refers to IS3 and IS4 as BtB3 and BtB4,
respectively.
---------------------------------------------------------------------------

    In its third analysis, Ramboll Environ examined the monthly
distribution of the 20% worst visibility days to see how many fell
within the November 21-January 20 curtailment period for 2008 in
comparison to 2000-2012. This analysis showed that 2008 had a lower
than average number of 20% worst visibility days within this period.
Ramboll Environ concluded that,

because more of the 20% worst visibility days would fall within the
curtailment period in a typical year, the actual visibility benefits of
the Interim Strategy would generally be larger than the modeling
results indicate.
    Ramboll Environ's analysis of the approximately 60-day curtailment
period used in Interim Strategy options IS3 and IS4 relied on post-
processing of modeling results to assess extending the period by 20,
40, 60, and 80 days. Ramboll Environ presented bar graphs showing the
amount by which extending the curtailment period impacted the strengths
of the directional results of the two-prong test. For prong 1, the
visibility benefit of the Interim Strategy increased very little as the
curtailment period was extended. For prong 2, Ramboll Environ stated
that even doubling the curtailment period would yield only a 0.002
deciview improvement over the proposed period, which Ramboll Environ
viewed as small. Therefore, SRP concluded that extending the
curtailment period would have only a small visibility benefit.
    Response: We acknowledge the additional analysis provided by SRP,
which supports the conclusion that 2008 is a representative year for
modeling and that modeling results for this single year are adequate
for evaluating the Interim Strategy under the two-prong test. Although
the Ramboll Environ analysis primarily addressed IS3 and IS4, the
curtailment period for IS2 (October 21-January 31) also includes the
months of November through January, so the same conclusion also applies
to IS2.
    We acknowledge the analysis of extending the curtailment period,
but we note that this analysis is not necessary to demonstrate that the
Interim Strategy would result in greater reasonable progress than BART.
It is sufficient that the modeling demonstrates that each of the
Interim Strategy options passes the two-prong test.

IV. Final Action

    For the reasons explained in our proposal and in our responses to
comments in this document, we have determined that the Coronado SIP
Revision will provide for greater reasonable progress toward natural
visibility conditions than BART. We have also determined that the
Coronado SIP Revision meets all other requirements of the CAA and the
EPA's implementing regulations. Therefore, we are approving the
Coronado SIP Revision into the Arizona SIP. Because this approval fills
the gap in the Arizona Regional Haze SIP left by the EPA's prior
partial disapproval with respect to Coronado, we are withdrawing those
portions of the Arizona Regional Haze FIP that address BART for
Coronado. Additionally, we are taking final action to remove those
portions of the Arizona SIP that have either been superseded by
previously-approved revisions to the Arizona SIP or are being
superseded by this final approval of the Coronado SIP revision.

V. Environmental Justice Considerations

    As explained above, the Coronado SIP Revision will result in
reduced emissions of both SO2 and PM10 compared
to the existing Arizona Regional Haze SIP and FIP requirements. While
the Coronado SIP Revision will result in fewer NOX
reductions than the Arizona Regional Haze FIP would have required
between 2018 and 2025, it will ensure that NOX emissions
remain at or below current levels until 2025, after which it will
require NOX emissions reductions equivalent to or greater
than would have been required under the Arizona Regional Haze FIP.
Furthermore, Coronado is located in an area that is designated
attainment, unclassifiable/attainment, or unclassifiable, or has not
yet been designated for each of the current NAAQS. Therefore, the EPA
believes that this action will not have potential disproportionately
high and adverse human health or environmental effects on minority,
low-income, or indigenous populations.

VI. Incorporation by Reference

    In this rule, the EPA is finalizing regulatory text that includes
incorporation by reference. In accordance with requirements of 1 CFR
51.5, the EPA is finalizing the incorporation by reference of the state
permit provisions described in the amendments to 40 CFR part 52 set
forth below. The EPA has made, and will continue to make, these
documents available through www.regulations.gov and at the EPA Region
IX Office (please contact the person identified in the FOR FURTHER
INFORMATION CONTACT section of this preamble for more information).
    Therefore, these materials have been approved by EPA for inclusion
in the SIP, have been incorporated by reference by EPA into that plan,
are fully federally enforceable under sections 110 and 113 of the CAA
as of the effective date of the final rulemaking of the EPA's approval,
and will be incorporated by reference by the Director of the Federal
Register in the next update to the SIP compilation.\79\
---------------------------------------------------------------------------

    \79\ 62 FR 27968 (May 22, 1997).
---------------------------------------------------------------------------

VII. Statutory and Executive Order Reviews

    Additional information about these statutes and Executive Orders
can be found at http://www2.epa.gov/laws-regulations/laws-and-executive-orders.

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

    This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review. This rule applies to only a single facility and is
therefore not a rule of general applicability.

B. Executive Order 13771: Reducing Regulations and Controlling
Regulatory Costs

    This action is not an Executive Order 13771 regulatory action
because this action approving revisions to a State Implementation Plan
and removing the applicable Federal Implementation Plan for Regional
Haze applies to only a single facility and is therefore is a Rule of
Particular Applicability that is exempted under Executive Order 12866.

C. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under
the PRA. This rule applies to only a single facility. Therefore, its
recordkeeping and reporting provisions do not constitute a ``collection
of information'' as defined under 44 U.S.C. 3502(3) and 5 CFR
1320.3(c).

D. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities. Firms
primarily engaged in the generation, transmission, and/or distribution
of electric energy for sale are small if, including affiliates, the
total electric output for the preceding fiscal year did not exceed 4
million megawatt hours. The owner of facility affected by this rule,
SRP, exceeds this threshold.

E. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or
more as described in UMRA, 2 U.S.C. 1531-1538, and does not
significantly or uniquely affect small governments.

F. Executive Order 13132: Federalism

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

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

    This action does not have tribal implications, as specified in
Executive Order 13175. It will not have substantial direct effects on
any Indian tribes, on the relationship between the federal government
and Indian tribes, or on the distribution of power and responsibilities
between the federal government and Indian tribes. Thus, Executive Order
13175 does not apply to this action.

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

    The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern health or safety risks that the EPA has
reason to believe may disproportionately affect children, per the
definition of ``covered regulatory action'' in section 2-202 of the
Executive Order. This action is not subject to Executive Order 13045
because it does not concern an environmental health risk or safety
risk.

I. Executive Order 13211: Actions Concerning Regulations That
Significantly Affect Energy Supply, Distribution, or Use

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

J. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards. The EPA is
not revising any technical standards or imposing any new technical
standards in this action.

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

    The EPA believes that this action does not have disproportionately
high and adverse human health or environmental effects on minority
populations, low-income populations, and/or indigenous peoples, as
specified in Executive Order 12898 (59 FR 7629, February 16, 1994). The
documentation for this decision is contained in section V above.

L. Determination Under Section 307(d)

    Pursuant to CAA section 307(d)(1)(B), the EPA has determined that
this action is subject to the provisions of section 307(d). Section
307(d) establishes procedural requirements specific to certain
rulemaking actions under the CAA. Pursuant to CAA section 307(d)(1)(B),
the withdrawal of the provisions of the Arizona Regional Haze FIP that
apply to Coronado is subject to the requirements of CAA section 307(d),
as it constitutes a revision to a FIP under CAA section 110(c).
Furthermore, CAA section 307(d)(1)(V) provides that the provisions of
section 307(d) apply to ``such other actions as the Administrator may
determine.'' The EPA determines that the provisions of 307(d) apply to
the EPA's action on the Coronado SIP Revision.

M. Congressional Review Act (CRA)

    This rule is exempt from the CRA because it is a rule of particular
applicability. The EPA is not required to submit a rule report
regarding this action under section 801 because this is a rule of
particular applicability that only applies to a single named facility.

N. Petitions for Judicial Review

    Under CAA section 307(b)(1), petitions for judicial review of this
action must be filed in the United States Court of Appeals for the
appropriate circuit by December 11, 2017. Filing a petition for
reconsideration by the Administrator of this final rule does not affect
the finality of this rule for the purposes of judicial review nor does
it extend the time within which a petition for judicial review may be
filed, and shall not postpone the effectiveness of such rule or action.
This action may not be challenged later in proceedings to enforce its
requirements (see section 307(b)(2)).

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Carbon monoxide,
Incorporation by reference, Intergovernmental relations, Lead, Nitrogen
dioxide, Ozone, Particulate matter, Reporting and recordkeeping
requirements, Sulfur dioxide, Visibility.

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

    Dated: September 28, 2017.
E. Scott Pruitt,
Administrator, EPA.

    For the reasons set forth in the preamble, the EPA amends 40 CFR
part 52 as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart D--Arizona

0
2. Section 52.120 is amended:
0
a. In paragraph (d), under the table heading ``EPA-Approved Source-
Specific Requirements'' by adding an entry for ``Coronado Generating
Station'' after the entry for ``Cholla Power Plant;''
0
b. In paragraph (e), under the table heading ``Table 1--EPA-Approved
Non-Regulatory and Quasi-Regulatory Measures'' by adding an entry for
``Coronado Generating Station'' after the entry for ``Cholla SIP
Revision.''

Sec.  52.120  Identification of plan.

* * * * *
    (d) * * *

                                                        EPA-Approved Source Specific Requirements
--------------------------------------------------------------------------------------------------------------------------------------------------------
         Name of source               Order/permit No.               Effective date                   EPA approval date                Explanation
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                       Arizona Department of Environmental Quality
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                      * * * * * * *
Coronado Generating Station.....  Permit #64169 (as         November 9, 2017................  October 10, 2017, [INSERT         Permit issued by Arizona
                                   amended by Significant                                      Federal Register CITATION].       Department of
                                   Revision #63088) Cover                                                                        Environmental Quality.
                                   Page and Attachment                                                                           Submitted on December
                                   ``E'': BART                                                                                15, 2016.
                                   Alternatives.

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

* * * * *
    (e) * * *
* * * * *

                                           Table 1--EPA-Approved Non-Regulatory and Quasi-Regulatory Measures
                           [Excluding certain resolutions and statutes, which are listed in tables 2 and 3, respectively] \1\
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                      Applicable  geographic or
      Name of SIP provision         nonattainment  area or title/         State submittal date              EPA approval date             Explanation
                                               subject
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                             The State of Arizona Air Pollution Control Implementation Plan
--------------------------------------------------------------------------------------------------------------------------------------------------------
                        Clean Air Act Section 110(a)(2) State Implementation Plan Elements (Excluding Part D Elements and Plans)
--------------------------------------------------------------------------------------------------------------------------------------------------------

                                                                      * * * * * * *
Arizona State Implementation      Source-Specific.................  December 15, 2016..............  October 10, 2017, [INSERT        BART Alternative
 Plan Revision to the Arizona                                                                         Federal Register CITATION].      for Coronado
 Regional Haze Plan for the Salt                                                                                Generating
 River Project Coronado                                                                                Station adopted
 Generating Station, excluding                                                                                December 14,
 Appendix B.                                                                                2016.

                                                                      * * * * * * *
--------------------------------------------------------------------------------------------------------------------------------------------------------
\1\ Table 1 is divided into three parts: Clean Air Act Section 110(a)(2) State Implementation Plan Elements (excluding Part D Elements and Plans), Part
  D Elements and Plans (other than for the Metropolitan Phoenix or Tucson Areas), and Part D Elements and Plans for the Metropolitan Phoenix and Tucson
  Areas.

* * * * *

0
3. Section 52.145 is amended by:
0
a. Removing and reserving paragraph (e)(1).
0
b. Removing paragraphs (e)(2)(iii)-(vi).
0
c. Removing and reserving paragraph (f).

[FR Doc. 2017-21604 Filed 10-6-17; 8:45 am]
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