obligated to approve a SIP that meets all of the applicable
requirements of the CAA. See 42 U.S.C. 7410(k)(3) (``In the case of any
submittal on which the Administrator is required to act under paragraph
(2), the Administrator shall approve such submittal as a whole if it
meets all of the applicable requirements of this chapter.''). The
Section 308 regulation grants states full discretion as to whether to
adopt the BART Alternative. In the current proposed rule, EPA also
acknowledges a state's discretion in approving alternative measures:
Finally, in . . . responding to concerns regarding ``impermissibly
vague'' language in Sec.  51.308(e)(3) that would allow a State to
``approve alternative measure that are less protective than BART,'' we
explained that ``[t]he State's discretion in this area is subject to
the condition that it must be reasonably exercised and that its
decision be supported by adequate documentation of its analyses.'' 81
FR 2004, 2012 (quoting 71 FR 60612, 60621 (Oct. 13, 2006)). Therefore,
the alternative measure is within the state's discretion, as long as it
is adequately supported.
    Response: We agree that states have discretion to adopt BART
alternatives; however, as the commenter explains, the state's
discretion is subject to a number of requirements, including that it be
reasonably exercised and adequately supported and that the state's
Alternative clearly provides greater reasonable progress than BART. The
CAA requires that states submit SIPs that contain such measures as may
be necessary to make reasonable progress toward achieving natural
visibility conditions, including the BART requirements. As EPA
explained when promulgating the regional haze regulations, ``[t]he
overarching requirement of the visibility protection provisions of
section 169A is to make reasonable progress toward the national goal of
eliminating visibility impairment. If greater reasonable progress can
be made through an approach that does not require source specific
application of BART, EPA believes that approach would comport with this
statutory goal.'' \81\ States have the opportunity to adopt alternative
measures in lieu of BART where the agency reasonably concludes that
more reasonable progress will thereby be attained toward the national
visibility goal.\82\ We explained these requirements in our co-proposal
as follows: ``[a]s described in our 2006 revisions to the RHR,
concerning BART alternatives, `[t]he State's discretion in this area is
subject to the condition that it must be reasonably exercised and that
its decisions be supported by adequate documentation of its analyses.'
''\83\
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    \81\ 64 FR 35714, 35739 (July 1, 1999).
    \82\ Id. (emphasis added).
    \83\ 81 FR 2004, 2006 (Jan. 6, 2016) (citing 71 FR 60612, 60621
(Oct. 13, 2006)).
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    While states have discretion to decide whether to adopt a BART
alternative in a SIP, such discretion does not extend to the authority
to adopt SIPs that will not ensure reasonable progress toward the
national visibility goal of preventing any future and remedying of any
existing visibility impairment in Class I areas. Such an interpretation
is also inconsistent with the legislative history, which stresses the
importance of the ``national goal'' \84\ of clear air quality in Class
I areas and ``preventing impairment of visibility,'' noting that ``the
millions of Americans who travel thousands of miles each year to visit
Yosemite or the Grand Canyon or the North Cascades will find little
enjoyment if . . . upon reaching the Grand Canyon it is difficult if
not impossible to see across the great chasm.'' \85\
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    \84\ 42 U.S.C. 7491(a)(1).
    \85\ H.R. Rep. No. 95-294, at 137 (1977).
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    Thus, we do not agree that Congress assigned states full discretion
in developing SIPs, because it is not clear how EPA's limited role
under such a scenario would assure attainment of the national goal or
imposition of the [better than] BART requirements where a state's BART
alternative demonstration does not demonstrate that the alternative
achieves greater reasonable progress. In view of the statutory
requirements, it is logical that EPA would evaluate the reasonableness
of the State's BART Alternative analysis in light of the purpose of the
regional haze program.
    As detailed in the sections in our co-proposal and based on our
evaluation and findings as detailed in Section I.B.1 of this document
and in our RTC document, we determined that, on balance, the evidence
does not show that the Alternative clearly achieves greater visibility
benefits than BART. Because the State's BART Alternative is not
approvable, we are obligated to disapprove it, develop BART analyses,
and then arrive at our own BART determinations for the four EGUs that
are subject-to-BART.
    Furthermore, this is a SIP review action, and we believe that EPA
is not only authorized, but required to exercise independent technical
judgment in evaluating the adequacy of the State's regional haze SIP,
including its BART Alternative analyses, just as EPA must exercise such
judgment in evaluating other SIPs. In evaluating other SIPs, EPA is
constantly exercising judgment about SIP adequacy, not just to meet and
maintain the NAAQS, but also to meet other requirements that do not
have a numeric value. In this case, Congress did not establish a
specific numeric value by which to measure visibility improvement;
instead, it established a reasonable progress standard and required
that EPA assure that such progress be achieved via implementation,
inter alia, of the Act's BART requirement. Here, we are exercising
judgment within the parameters laid out in the CAA and our regulations.
    Our evaluation of the State's BART Alternative is presented in
section I.B.1 and in our RTC document.
    Comment: The State commented that EPA mistakenly imposes additional
inapplicable requirements in its evaluation of Utah's regional haze
SIP. Greater reasonable progress under Section 308(e)(2) can be
demonstrated using either one of two methods: (1) Greater emission
reductions than under BART (Section 308(e)(3)); or (2) the weight-of-
evidence test, consisting of a number of requirements that the state
weighs to conclude which option achieves greater reasonable progress
(section 308(e)(2)). See 40 CFR 51.308(e)(2) and (3). The state has
discretion to choose one method over the other. See WildEarth Guardians
v. E.P.A., 770 F.3d 919, 935-37 (10th Cir.

2014). The Tenth Circuit characterized the former approach as
``quantitative'' and the latter as ``qualitative,'' ultimately ruling
that EPA can properly rely on qualitative factors in applying the
``weight-of-evidence test.'' See id. at 934-35 (EPA's choice of
qualitative standard was ``permissible under the EPA's interpretation
of its regulations.'').
    Utah submitted its BART Alternative under Section 308(e)(2),
purposefully electing to make its determination that the alternative
program achieves greater reasonable progress under the ``weight-of-
evidence'' test. EPA analyzed Utah's BART Alternative in both co-
proposals under the section 308(e)(3) ``greater emissions reductions
test'' in addition to the ``weight-of-evidence'' analysis. See 81 FR
2004, 2021, 2028. EPA proposed that Utah's BART Alternative does not
result in greater emission reductions because ``the total
NOX emissions are greater under the BART Alternative than
the BART Benchmark,'' even though ``in the aggregate there are fewer
SO2 and PM10 emissions for the BART Alternative .
. . .'' Id. at 2028. EPA erroneously imposed Section 308(e)(3)
requirements on Utah's BART Alternative in addition to the Section
308(e)(2) weight-of-evidence test. EPA must withdraw its analysis of
Utah's BART Alternative under the greater emissions reductions test
because, as Utah clearly explained, the State never intended its data
to satisfy this test.
    Response: We agree in part and disagree in part with this comment.
In developing a BART Alternative SIP, we agree that a state has the
discretion to choose between the ``greater emission reduction'' test
(section 308(e)(3)) and the ``weight-of-evidence'' test (section
308(e)(2)). Utah's comments clarify that they elected the weight-of-
evidence test, and so we clarify and modify our evaluation of the
State's SIP submittal. We therefore clarify that we are not
disapproving the SIP under the elements of the section 308(e)(3) test
as we had proposed.\86\
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    \86\ 81 FR 2004, 2028 (``Therefore, we propose to disapprove
Section XX.D.6.c. of the Utah SIP under the test in 40 CFR
51.308(e)(3).'').
---------------------------------------------------------------------------

    The State's submittal, however, asserted that the BART Alternative
is better than BART based in part on the metric that compared annual
emissions of the three visibility impairing pollutants in the
aggregate. There is no requirement in section 308(e)(2) for the State
to compare annual emissions of visibility pollutants in the aggregate.
Rather, as we explained in our proposal, we have addressed this issue
under section 308(e)(3); our interpretation under that provision also
applies under section 308(e)(2). Specifically, if under section
308(e)(2) a state compares annual emissions of visibility in the
aggregate to determine whether a BART alternative ``results in greater
emission reductions,'' we examine whether each of the visibility
causing pollutants is less under the alternative. For the reasons
explained in our proposal and in section I.B.1.c.i of this document, we
have not approved a BART alternative where one or more of the specific
pollutants under the BART alternative is greater than it would be under
the BART benchmark.\87\
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    \87\ EPA's interpretation of the requirement under 40 CFR
51.308(e)(3) that the alternative measure ``results in greater
emission reductions'' has been that the emission reduction
comparisons are pollutant specific. We have applied this
interpretation in evaluating BART alternatives and we have not
looked at a total emissions profile that combines emissions of
multiple pollutants to determine whether a BART benchmark or a BART
alternative is ``better,'' except where every visibility impairing
pollutant is reduced by a greater amount under the BART alternative.
See 79 FR 9318, 9335 (Feb. 18, 2014) (proposed approval of Arizona
BART Alternative for Sundt Unit 4); 79 FR 52420 (Sept. 3, 2014)
(final approval of Arizona BART Alternative for Sundt Unit 4); 77 FR
18052, 18073-75 (Mar. 26, 2012) (proposed approval of Colorado BART
Alternative, no modeling required where the 40 CFR 51.308(e)(3) test
was met); 77 FR 76871 (Dec. 31, 2012) (final approval of Colorado
BART Alternative). EPA has not relied on a total emissions profile
that combines emissions of multiple pollutants together to determine
that either BART or a BART alternative is ``better,'' because
visibility modeling is the most appropriate method to assess the
overall improvements in visibility impacts from control scenarios
where reductions of multiple pollutants are considered, except where
every visibility impairing pollutant is reduced by a greater amount
under the alternative. As we have explained, ``[e]ach of the five
pollutants which cause or contribute to visibility impairment has a
different impact on light extinction for a given particle mass,
making it therefore extremely difficult to judge the equivalence of
interpollutant trades in a manner that would be technically
credible, yet convenient to implement in the timeframe needed for
transactions to be efficient. This analysis is further complicated
by the fact that the visibility impact that each pollutant can have
varies with humidity, so that control of different pollutants can
have markedly different effects on visibility in different
geographic areas and at different times of the year.'' See 64 FR
35714, 35743(July 1, 1999). As other Agency actions on BART
alternatives have explained, modeling assesses ``both pollutants'
chemical aerosol formation mechanisms and impacts on visibility,''
(see 78 FR 79344, 79355; Dec. 30, 2013) which allows evaluation of
the ``relative visibility impacts from the atmospheric formation of
visibility impairing aerosols of sulfate and nitrate.'' See 79 FR
33438, 33440 (June 11, 2014).
---------------------------------------------------------------------------

    Therefore, as we did in our proposal, it is reasonable to apply our
interpretation of the section 308(e)(3) ``greater emission reductions''
element under section 308(e)(2) as well, because the same concerns
regarding the relationship between reductions of multiple pollutants
and visibility improvements are also relevant in the weight-of-evidence
context.
    Comment: PacifiCorp asserted that EPA is not empowered under the
CAA to require compliance with both the SIP proposal and the FIP
proposal. As a practical matter, that is precisely what EPA proposes to
do to the extent it approves the FIP proposal. This is because
PacifiCorp already has implemented the SIP proposal as required by Utah
law. If EPA were to select the FIP proposal, it would do so knowing
\88\ that PacifiCorp would be required to implement both the SIP
proposal and the FIP proposal. Nothing in CAA or regional haze rules
allows EPA to require such a result when the proposed action itself
states that EPA ``intends to finalize only one proposal.'' See 81 FR
2004, 2006.
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    \88\ EPA is well aware that the Utah SIP, as it has been
implemented over time, became binding state law in regard to the
Utah BART Units and ultimately the other units covered by the BART
Alternative. This makes it particularly egregious that, even though
EPA knew that PacifiCorp was required to expend hundreds of millions
of dollars to fully implement the BART Alternative under state law,
EPA said nothing about its intention to issue a competing co-
proposal until after PacifiCorp had completed all of the emission
reductions required under the Utah SIP. See Letter from Carl Daly to
Bryce Bird, Re. EPA Region 8 Comments on Utah's February 2015 Draft
Regional Haze SIP Revision, at 1 (May 1, 2015) (commenting on the
then-proposed Utah SIP including the BART Alternative). This
secretive approach by EPA also caught the Utah Division of Air
Quality off guard as explained in their oral comments during the
January 26, 2016 hearing: ``Throughout the SIP development process,
we worked as regulatory partners, closely and extensively with EPA
staff to ensure that Utah's Alternative to BART SIP revision met all
the requirements of the Clean Air Act and was approvable by EPA. The
EPA should approve the option that Utah developed while in close
consultation with EPA and not the option that Utah was not even
aware was being prepared or under consideration until it was
proposed in the Federal Register.''
---------------------------------------------------------------------------

    For all of the reasons stated earlier, EPA should approve the Utah
SIP as stated in the SIP proposal, and should reject the FIP proposal.
What EPA cannot do, and indeed is not empowered under the CAA to
require, is compliance with both the SIP proposal and the FIP proposal.
    Response: We disagree with this comment. As explained elsewhere,
the CAA requires that states submit SIPs that contain such measures as
may be necessary to make reasonable progress toward achieving natural
visibility conditions, including the BART requirements. EPA is acting
under its authority pursuant to the CAA in disapproving portions of the
SIP submittal and promulgating the FIP. We have the duty to ensure that
regional haze SIP submittals meet the requirements of the Act and the
RHR.\89\ While states have the opportunity to adopt alternative
measures in lieu of

BART, their discretion in this area is subject to the condition that it
must be reasonably exercised and that their decisions be supported by
adequate documentation of its analyses.
---------------------------------------------------------------------------

    \89\ See CAA sections 169A and 110(k)(3).
---------------------------------------------------------------------------

    Therefore, we do not agree that we are prohibited from identifying
deficiencies in the Utah SIP submittal after the State rulemaking
process is complete, and the commenter cites nothing in the Act to the
contrary. While a state may adopt regulations that are effective as a
matter of state law before EPA goes through its rulemaking process to
evaluate the proposed SIP elements, those state rules are not federally
enforceable because any SIP submittal ``shall not be treated as meeting
the requirements of this chapter until the Administrator approves the
entire plan revision as complying with the applicable requirements.''
42 U.S.C. 7410(k)(3). The State's and EPA's roles in this process were
understood in PacifiCorp statements. For example, in response to a
question provided during rebuttal testimony that asked whether the
regional haze rules are final, the Company explained that the 2011 Utah
and Wyoming SIP submittals ``are final insofar as state action is
considered'' and recognized that ``these submittals have not yet been
approved by the Environmental Protection Agency.'' \90\
---------------------------------------------------------------------------

    \90\ Rebuttal Testimony of Cathy S. Woolums, at 26. (June 30,
2011). (Available in the docket at https://www.regulations.gov/#!documentDetail;D=EPA-R08-OAR-2015-0463-0167).
---------------------------------------------------------------------------

    The commenter suggests that measures in Utah's SIP submittal became
``binding state law in regard to the Utah BART Units'' and ``the other
units covered by the BART Alternative'' prior to EPA's final action.
The commenter merely suggests there are state law provisions but does
not provide citations to any state law specific provisions.\91\ It
appears, however, that the commenter may be referring to measures
established pursuant to the State's permit process. If this is, indeed,
what the commenter is referring to, both the CAA and our regulations
require that emission limits be established pursuant to a BART or BART
alternative determination, and be contained in an EPA-approved SIP.\92\
The fact that Utah chose to use its permit process to establish
emission limits for its BART sources before EPA completed its review of
the State's SIP submittal has no bearing on EPA's authority and
obligation to conduct this review and to approve or, if necessary,
disapprove the State's submittal.
---------------------------------------------------------------------------

    \91\ Utah's Effective rule explains that ``[w]hile Utah has
chosen to meet the NOX BART requirement through
alternative measures . . . the enforceable emission limits for both
NOX and SO2 established in the approval orders
and in the SIP for the four EGUs also met the presumptive emission
rates for both NOX and SO2 established in
Appendix Y independently of the alternative program.'' Effective
Rule at page E-12, Section XX, p. 168 (adopted by the Board on June
3, 2015), available in the docket at https://www.regulations.gov/#!documentDetail;D=EPA-R08-OAR-2015-0463-0002. The presumptive
emission limits in the BART Guidelines are rebuttable. The
presumptive emission limits apply to power plants with a total
generating capacity of 750 MW or greater insofar as these sources
are required to adopt emission limits at least as stringent as the
presumptive limits, unless after considering the five statutory
factors, the State determines that the presumptive emission limits
are not appropriate.
    \92\ Congress required EPA to promulgate regulations to assure
``reasonable progress'' toward meeting the national goal and
compliance with section 169A. The regulations require the submission
of regional haze SIPs for states with Class I areas within their
borders and states whose emissions ``may reasonably be anticipated
to cause or contribute to any impairment of visibility'' in a Class
I area outside their borders. 42 U.S.C. 7491(b)(2), 7491(e)(2). All
SIPs must include ``enforceable emission limitations and other
control measures, means, or techniques . . . as well as schedules
and timetables for compliance, as may be necessary or appropriate to
meet the applicable requirements of [the Act].'' CAA section
110(a)(2)(A). Regional haze SIPs must include emission limits,
compliance schedules, and other measures ``as may be necessary to
make reasonable progress toward meeting the national goal.'' 42
U.S.C. 7491(b)(2).
---------------------------------------------------------------------------

    Finally, EPA's comment letter on the State's proposed SIP clearly
explained that ``we will only come to a final conclusion regarding the
regional haze program for Utah when we take action on the program
through our own public notice-and-comment rulemaking.'' \93\ Our letter
further explained to the State that, ``we are working towards meeting
our legal obligations that have resulted from our January 2013 partial
disapproval action for Utah's May 2011 regional haze SIP.'' EPA comment
letters are intended to help improve any SIP revision that is under
development, but they do not constitute agency action on that SIP
revision or constitute any assurance of positive action on that
revision upon submission and review. Instead and always, EPA has to
formally discharge its responsibilities to review any SIP submittal.
Moreover, the CAA does not require EPA to participate in state
proceedings related to a state's SIP submission, nor does it preclude
EPA from carrying out its statutory duty to disapprove an inadequate
SIP if EPA does not voice concerns during state proceedings. The CAA
requires EPA to issue a FIP when states have not met their obligations
under the CAA. Therefore, EPA is promulgating this FIP to fill the
regulatory gap created by the partial disapproval of Utah's SIP
submittals. Despite the existence of a FIP, the State retains its
authority to submit future regional haze SIPs consistent with CAA and
RHR requirements; we do not discount the possibility of a future,
approvable SIP submission that results in the modification or
withdrawal of the FIP.
---------------------------------------------------------------------------

    \93\ Letter from Carl Daly to Bryce Bird, Re. EPA Region 8
Comments on Utah's February 2015 Draft Regional Haze SIP Revision,
at 1 (May 1, 2015). (Available in the docket at https://www.regulations.gov/#!documentDetail;D=EPA-R08-OAR-2015-0463-0160).
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C. Reasonableness Standard

    Comment: One commenter asserted that EPA arbitrarily and
capriciously applies two inappropriate standards to the Utah SIP
proposal. The commenter stated that, in an attempt to replace Utah's
determination with its own, EPA imposes a ``Reasonableness Standard''
without concluding the Utah SIP contains data or methodological flaws--
the limited circumstances under which courts have upheld use of this
standard--and also imposes a ``Complexity of Evaluation'' standard
which finds no support in the CAA or applicable regulations.
    The commenter also asserted that EPA is prohibited from imposing
additional requirements upon its approval/disapproval of a SIP that do
not qualify as ``applicable requirements.'' EPA is not correct in its
attempt in the proposed action to impose additional requirements on its
evaluation of the BART Alternative and Utah SIP that are different than
the applicable BART alternative requirements.
    1. Reasonableness Standard -EPA asserts that Utah ``has several
options for making the greater reasonable progress determination [and
it] elected to use two separate approaches.'' \94\ See 81 FR at 2006.
EPA further states that it will evaluate both of those approaches in
deciding whether to approve the Utah SIP. EPA then makes the blanket
assertion that ``the State's discretion in this area is subject to the
condition that it must be reasonably exercised and that its decisions
be supported by adequate documentation of its analysis.''
(``Reasonableness Standard.'') See 81 FR at 2006. Although the use of
words like ``reasonable'' and ``adequate'' have common sense appeal in
the abstract, EPA may not apply this standard in a way that allows EPA
to discard the state's discretion and instead impose EPA's own will.
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    \94\ As explained below [referring to PacifiCorp's comment
document], EPA is simply wrong in concluding that Utah used two
separate approaches to demonstrate greater reasonable progress.
Therefore, EPA's stated basis for imposing the Reasonableness
Standard does not support EPA's effort to do so.
---------------------------------------------------------------------------

    In addition, the present circumstances regarding the SIP proposal
are far different than those circumstances in

which courts have upheld EPA's use of a similar Reasonableness Standard
in other regional haze settings. For example, in North Dakota v. EPA,
730 F.3d 750, 760 (8th Cir. 2013), the court allowed EPA's use of the
Reasonableness Standard under those circumstances where the state's
BART determination contained ``data flaws that led to an overestimated
costs of compliance.'' Also, Oklahoma v. EPA, 723 F. 3d 1201, 1212
(10th Cir. 2013) reached a similar conclusion based on ``methodological
flaws.''
    In the case of the SIP proposal, however, EPA proposes to approve
the BART Alternative based on compliance with the applicable BART
alternative requirements \95\ and without also concluding that the BART
Alternative contains ``data flaws'' or ``methodological flaws.''
Therefore, the factual bases for allowing EPA to apply a Reasonableness
Standard do not exist in regard to the BART Alternative and EPA should
not attempt to apply such a standard here--particularly as a basis for
rejecting the BART Alternative.\96\
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    \95\ See generally 81 FR 2004, 2021-26.
    \96\ This is not to say that EPA lacks any role in reviewing and
approving the Utah SIP. Indeed, the latest court to weigh in on
EPA's review authority makes clear that ``Congress intended that
EPA, not the states alone, ultimately ensure that state
determinations as to regional haze comply with the [Clean Air] Act.
. ..'' Arizona ex rel. Darwin v. EPA, Nos. 13-70366, 13-70410, 2016
U.S. App. LEXIS 3196, at *19-20 (9th Cir. Feb. 24, 2016). Although
PacifiCorp agrees that EPA has a role to play in making sure the
Utah SIP complies with the CAA and applicable requirements, it also
notes that EPA must do so in a way that does not undermine the role
of states like Utah to which ``Section 169A [of the CAA] gives. .
.substantial responsibility in determining appropriate BART [and
BART Alternative] controls.'' The court goes on to make clear that
``EPA may not disapprove reasonable state determinations that comply
with the relevant statutory and regulatory requirements.'' Id. at
*22. Such is the case with the Utah SIP.
---------------------------------------------------------------------------

    2. Complexity of Evaluation Standard--EPA also is wrong in its
attempt to count among applicable requirements the unsupported
conclusion that the ``complexity of our evaluation'' somehow
necessitates EPA soliciting comments not only on the SIP proposal, but
also on the competing FIP proposal. See 81 FR 2006.\97\ Even taking at
face value the assertion that analyzing the Utah SIP is
``complicated,'' that alone does not require EPA to evaluate the Utah
SIP differently than any other regional haze SIP, nor does it justify
EPA in presenting dueling co-proposals.\98\ In other words, EPA has
simply conjured up this new ``complexity'' requirement \99\ out of thin
air in an attempt to support its offering of the competing FIP
proposal. EPA is acting arbitrarily and without legal authority by
seeking comment on the FIP proposal based on what EPA calls the
``complexity of our evaluation'' and for this reason EPA should
withdraw the FIP proposal and approve the SIP proposal as proposed.
---------------------------------------------------------------------------

    \97\ EPA attempts to further support this contrived
``complexity'' requirement by repeatedly stating that such a
requirement exists, as if repetition alone somehow can bring an
imaginary requirement into existence (i.e., ``In light of the
variety of metrics Utah used, this is a complicated analysis. . .
;'' ``The complexity of our evaluation leads us to propose and
solicit comments on two conclusions and two courses of action . . .
;'' ``Given the complexities in evaluating these co-proposals, EPA
wants to ensure that our final decision is based on the best and
most currently available data and information, and is taken with the
fullest possible consideration of public input.'') See 81 FR 2004,
2006.
    \98\ The Tenth Circuit Court of Appeals, which considered
whether EPA's approval of a BART Alternative for SO2
emissions was appropriate, did not conclude that EPA's analysis of
the alternative program was, by its nature, more complicated than a
BART analysis. See generally WildEarth Guardians v. EPA, 770 F.3d
919 (10th Cir. 2014).
    \99\ EPA further attempts to justify its rationale for
considering the FIP proposal by asserting, as explained in footnote
3, the need to ``ensure that our final decision is based on the best
and most currently available data and information, and is taken with
the fullest possible consideration of public input.'' EPA already is
charged with ensuring that any final decision is based on the best
current data and information available. See 71 FR 60612, 60622 (Oct.
13, 2006) (final rule on revisions to provisions governing
alternative source-specific BART determinations); see also 5 U.S.C.
706(2). EPA already is required to make a decision based on the
fullest possible consideration of public input. See 5 U.S.C. 553(c).
Re-stating these fundamental principles does not allow EPA to
bootstrap itself into also considering a competing coproposal (the
FIP proposal) when the SIP proposal already meets all Applicable
BART Alternative Requirements as EPA itself has proposed to
conclude. Arizona ex rel. Darwin at *22 (stating that ``EPA may not
second-guess reasoned, legally compliant state decisions'')
(internal citations and quotations omitted).
---------------------------------------------------------------------------

    Response: We disagree with most of these comments. First, we
disagree that we have used a ``reasonableness standard'' in a manner
that is inconsistent with our prior actions or as a way to limit the
State's discretion. As discussed elsewhere, EPA has a duty to review
Utah's regional haze SIP, including its BART Alternative, for
compliance with the applicable requirements of the CAA and the RHR.
Based on our review of the SIP, we proposed to determine that certain
elements of Utah's regional haze SIP met the applicable requirements,
and we proposed to approve those elements. However, for the reasons
explained in detail in our proposed action and elsewhere in this
document, we have concluded that, with regard to other elements, the
State did not exercise its discretion in a reasonable manner, i.e., in
a manner consistent with the requirements and goals of the CAA and RHR.
Based on these findings, we are required to partially disapprove Utah's
regional haze SIP submittal.
    As discussed in detail elsewhere, the CAA provides EPA with the
authority to review and reject an inadequate regional haze SIP
submittal. Oklahoma v. EPA, 723 F.3d 1201, 1207-08 (10th Cir. 2013)
(EPA may not approve a submittal that does not adhere to applicable
statutory and regulatory requirements). Contrary to the commenter's
assertions, our analysis and decision here is entirely consistent with
the North Dakota and Oklahoma decisions. The RHR requires a state to
demonstrate that its BART alternative achieves greater reasonable
progress than BART, 40 CFR 51.308(e)(2), and Utah chose to make this
demonstration using a weight-of-evidence analysis. In our review, EPA
found a number of flaws in this analysis. Based on this evaluation and
findings as detailed in Section I.B.1 of this document and in our RTC
document, we determined that, on balance, the evidence does not show
that the Alternative clearly achieves greater visibility benefits than
BART.
    Second, we disagree with the assertions regarding creation of a new
complexity standard. The commenter misunderstands and misconstrues our
proposed action. We did not create a new complexity standard, rather we
explained that we were considering complex information and that it was
a close call for EPA to decide whether the evidence presented by the
State clearly demonstrated that the BART Alternative would achieve
greater reasonable progress than BART (the complexity of our evaluation
leads us to propose and solicit comment on two conclusions and courses
of action because several of the metrics appear to support the State's
analyses, while others do not appear to support the Alternative).\100\
Contrary to the commenter's assertions, we merely explained that the
information in the State's SIP submittal was complex; we did not create
a new standard by which to evaluate SIP submittals. Our proposed action
clearly explained that some metrics appeared to support approval, while
others metrics appeared to support a disapproval.
---------------------------------------------------------------------------

    \100\ 81 FR 2004, 2006 (Jan. 14, 2016) (emphasis added).
---------------------------------------------------------------------------

    Therefore, given that EPA's evaluation of the information before us
presented a close call, and in order to provide a fair and meaningful
process for all members of the public, we used the co-proposal
approach. This approach provided an opportunity for the public to
comment on both potential courses of action, i.e., approval or
disapproval of the State's BART Alternative. Recognizing the

information before the Agency was possibly susceptible to both
interpretations, our two proposed conclusions and courses of action
were as follows: ``(1) The State's submittal meets the test above and
we approve the BART Alternative; or (2) the State's submittal falls
short of meeting this test and we disapprove the BART Alternative and
promulgate a FIP for NOX BART.''
    We exercised our rulemaking discretion and structured the action
using the co-proposal approach so that our action would enable all
interested parties to have the opportunity to provide meaningful and
timely comment on either or both approaches. In structuring the action
in this way, the interested public had notice of the proposals under
consideration and whether they had interests at stake. This balanced
approach was fair in that it provided all interested parties with the
options EPA contemplated in taking final action, as well as providing
an opportunity to comment on the full range of potential actions. The
commenter cites to no CAA provision that restricts EPA's authority to
present co-proposals. EPA often provides alternative approaches for
final Agency action in our SIP rulemaking proposals, as we did here.
Additionally, even assuming that EPA's proposed action on the Utah
regional haze SIPs articulated new ``complexity'' grounds for
evaluating a regional haze SIP, the proposed action provided the public
with the opportunity to comment. As evidenced by the commenter's
submission, the commenter had the opportunity to provide input on this
purported new standard to evaluating the Utah regional haze SIP and to
identify any concerns associated with the statements at issue.
Therefore, even if we had created a new complexity standard, which we
did not, it would have been properly proposed and applied in this
instance.
    As explained above, the EPA proposal identified several weaknesses
and flaws in the State's SIP submittal in the proposed rulemaking,\101\
and as explained in this final action, other commenters have made us
aware of additional weaknesses and uncertainties in the SIP
submittal.\102\ Therefore, EPA is finalizing our co-proposal to
disapprove the BART Alternative and promulgate a FIP for NOX
BART, which this commenter recognizes EPA has a role and authority to
do.
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    \101\ Our proposal evaluated the State's use of the information
from the metrics and identified weaknesses and flaws, for example:
(1) The State's characterization of the 98th percentile modeling
results that did not support its BART Alternative, was inconsistent
with EPA's interpretation of and reliance on that metric; (2) the
comparison of the results from the total annual emissions reductions
was inconsistent with how we have interpreted our regulations; (3)
the results from the modeling for the number of days the Alternative
provided significant visibility impairment showed mixed results,
with some results favoring the Alternative, while other results did
not support the Alternative; (4) the annual average metric only
marginally supported the Alternative, and showed less or equal
visibility at four of nine Class I areas; and (5) the energy and
non-air quality and cost metrics do not have a direct bearing on
whether the Alternative achieves greater reasonable progress.
    \102\ Our RTC document provides details on the additional
weaknesses and uncertainties that commenters brought to our
attention.
---------------------------------------------------------------------------

    Furthermore, as explained elsewhere, we appreciate and clarify in
this final action that the State did not intend to have its BART
Alternative evaluated under both the 40 CFR 51.308(e)(2) and section
308(e)(3) tests. We, therefore, based our final action on our
evaluation of the State's submittal under Sec.  51.308(e)(2)'s weight-
of-evidence test.
    Finally, regarding the commenter's cross-reference to comments
dated August 26, 2013, we explained in our final action in the Wyoming
regional haze rulemaking that we disagreed with the comments in that
context and we continue to disagree here.\103\
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    \103\ ``As explained in our proposed rulemaking for section
51.309(d)(4)(viii), we explained that the provision `is intended to
clarify that if EPA determines that the SO2 emission
reductions milestones and backstop trading program submitted in the
section 51.309 SIP makes greater reasonable progress than BART for
SO2, this will not constitute a determination that BART
for PM or NOX is satisfied for any sources which would
otherwise be subject to BART for those pollutants' (emphasis added).
70 FR 44169 (Aug. 1, 2005). EPA does not interpret this rule to mean
that there are different BART requirements for section 308 and 309
regional haze SIPs. EPA's rulemaking made no finding that BART
determinations conducted for a state submitting a SIP under section
51.309 should be conducted any differently than a state submitting a
FIP under only section 308. The use of the word `necessary' in
section 51.309(d)(4)(viii) was to explain that some states may have
BART NOX emission limitations, while others may not. As
already explained elsewhere in proposal and our response to other
comments, Wyoming did not conduct a proper evaluation of the five
statutory factors, as required by 40 CFR 51.308(e)(1)(ii)(A) and
section 169A(g) of the CAA.
    EPA also disagrees with the commenter's assertion that a BART
submission is discretionary. 40 CFR 51.309(d)(4)(viii) is clear in
that the implementation plan `must' contain BART requirements. The
proposed rulemaking explained that the provision that provides that
`[a]ny such BART provisions may be submitted pursuant to either
Section 51.308(e)(1) or 51.308(e)(2),' was included to `allow States
the flexibility to address these BART provisions either on a source-
by-source basis under Section 51.308(e)(1), or through an
alternative strategy under Section 51.308(e)(2).' 70 FR 44169 (Aug.
1, 2005).
    Moreover, EPA's proposal made clear that `[i]n limited
circumstances, it may be possible for a State to demonstrate that an
alternative program which controls only emissions from
SO2 could achieve greater visibility improvement than
application of source-specific BART controls on emissions of
SO2, NOX and/or PM. We nevertheless believe
that such a showing will be quite difficult to make in most
geographic areas, given that controls on SO2 emissions
alone in most cases will result in increased formation of ammonium
nitrate particles.' 70 FR 44169 (Aug. 1, 2005). Wyoming's RH SIP
does not include a demonstration that the backstop SO[2] trading
program under Section 51.309 achieves greater visibility improvement
than application of source-specific PM BART controls. Therefore,
Wyoming's Section 51.309 SIP does not provide the adequate level of
visibility improvement to meet the BART requirements
    With respect to the relationship of BART and requirements for
reasonable progress under 40 CFR 51.308, EPA interprets the
reasonable progress requirements to apply to BART sources. As
explained in our guidance, due to the similarity of the BART and
reasonable progress factors, states may reasonably rely on their
BART determinations to show reasonable progress for those sources
for the first planning period. However, BART is an independent
requirement of the statute and the RHR. We have disapproved certain
BART determinations by Wyoming not due to a failure to make
reasonable progress, but due to a failure to consider the BART
factors appropriately.'' 79 FR 5032, 5098, 5099 (Jan. 30, 2014).
---------------------------------------------------------------------------

D. Compliance With 40 CFR 51.308

    Comment: Two commenters noted that EPA's FIP proposal is
unnecessary because EPA already found Utah is making the required
``reasonable progress.'' The goal of the RH program is to make
``reasonable progress'' towards the statute's national visibility goal.
Accordingly, EPA promulgated regulations ``to assure . . . reasonable
progress toward meeting'' the national visibility goal, section
7491(b)(2), and mandated that EPA's regulations contain ``such emission
limits, schedules of compliance and other measures as may be
necessary'' to assure such progress towards meeting that goal,
``including'' a requirement that states make BART determinations. Id.
As EPA has stated, ``BART is one component of long term strategies to
make reasonable progress.'' Regional Haze Regulations and Guidelines,
70 FR 39137.
    Because BART's purpose is to make reasonable progress, EPA adopted
regulations exempting states from making BART determinations if they
can show that other measures for large stationary sources will achieve
greater reasonable progress. 40 CFR 51.308(e)(2) (2012). EPA defended
those regulations in court by arguing that BART is one of a number of
``emission limits, schedules of compliance and other measures'' that
``must'' be included in a SIP ```as may be necessary to make reasonable
progress toward national visibility goals.' '' Ctr. for Energy and
Econ. Dev. v. EPA, 398 F.3d 653, 659-60 (D.C. Cir. 2005) (confirming
BART is but one measure for achieving ``reasonable progress''); Cent.
Arizona Water Conservation Dist. v. EPA, 990 F.2d 1531, 1534 (9th Cir.
1993) (same). If an alternative can better achieve those

goals, EPA has stated that BART would not be ``necessary to make
reasonable progress.'' Id. The court agreed with EPA's analysis,
although it overturned EPA on other grounds. Id. As the court said,
``the focus of the Clean Air Act was to achieve `actual progress and
improvement in visibility,' 42 U.S.C. 7492(b), not to anoint BART the
mandatory vehicle of choice.'' Id. at 660.
    As EPA recognizes, in some circumstances no BART controls may be
necessary to make reasonable progress. It follows that in other
circumstances, depending on a state's reasonable- progress goals and
expected non-BART emission reductions, BART controls of varying
stringency may be necessary. Consistent with this goal, EPA has
approved Utah's ``reasonable progress'' determination for its RH SIP in
its entirety. See ``Approval, Disapproval and Promulgation of State
Implementation Plans; State of Utah; Regional Haze Rule Requirements
for Mandatory Class I Areas Under 40 CFR 51.309,'' published at 77 FR
74355, 74367-68 (Dec. 14, 2012). EPA found that ``the State met all
reasonable progress requirements for the Class I areas,'' including by
implication any required NOX BART limits. In fact, EPA
stated that Utah's 2008 RH SIP, including BART controls identified in
that 2008 RH SIP, would result in ``a significant decrease in
stationary source NOX and SO2 emissions.'' Id.
EPA further found that the NOX BART controls adopted by Utah
for the Hunter and Huntington EGUs at issue would decrease
NOX emissions by ``6,200 tons [annually] between 2002 and
2018.'' Id. Therefore, EPA acknowledged that Utah's NOX BART
limits and controls are all that are required to achieve ``reasonable
progress,'' and no further NOX BART requirements should be
imposed by EPA through its FIP proposal.
    Thus, EPA cannot validly judge a state's BART determination outside
of its reasonable progress context. Owasso Indep. Sch. Dist. No. I-011
v. Falvo, 534 U.S. 426, 434 (2002) (``the words of a statute must be
read in their context and with a view to their place in the overall
statutory scheme.'').
    Response: EPA disagrees with these comments. The commenters appear
to be asserting that, since EPA approved Utah's 2011 SIP submission as
meeting the reasonable progress requirements of 40 CFR 51.309 with
regard to SO2, no further controls are necessary to meet the
RHR's requirements for NOX and PM. However, this assertion
ignores our statements in the BART Alternatives rulemaking that an EPA
determination that a backstop trading program satisfies a state's
reasonable progress obligations for SO2 under 40 CFR 51.309
does not satisfy that state's obligation to address NOX and
PM requirements under 40 CFR 51.308(e)(1) or (2). In this rulemaking,
EPA proposed amendments to the stationary source NOX and PM
provisions within Sec.  51.309 precisely in order to ``clarify that if
EPA determines that the SO2 emission reductions milestones
and backstop trading program in the Sec.  51.309 SIPs makes greater
reasonable progress than BART for SO2, this will not
constitute a determination that BART for PM or NOX is
satisfied for any sources which would otherwise be subject to BART for
those pollutants.'' \104\ The final rulemaking reinforced that a
reasonable progress determination for SO2 under Sec.
51.309's backstop trading program does not satisfy the emission
reductions requirements for non-SO2 pollutants.\105\
---------------------------------------------------------------------------

    \104\ 70 FR 44154, 44169 (Aug. 1, 2005) (emphasis added).
    \105\ 71 FR 60612, 60626 (Oct. 13, 2006).
---------------------------------------------------------------------------

    We also took this position in another recent regional haze action,
in which we found that the state's approved SO2 alternative
under Sec.  51.309 did ``not provide the adequate level of visibility
improvement to meet the [non-SO2] BART requirements.'' \106\
We then reiterated that ``BART is an independent requirement of the
statute and the RHR.'' \107\ Our statements in both the national and
regional contexts make it clear that a reasonable progress
determination for an SO2 backstop trading program under
Sec.  51.309 does not relieve a state of its obligation to satisfy
NOX and PM BART. EPA thus can judge a state's BART
determination outside the reasonable progress context, as they are
independent requirements.
---------------------------------------------------------------------------

    \106\ 79 FR 5032, 5099 (Jan. 30, 2014) (final partial approval/
partial disapproval of Wyoming regional haze SIP submission).
    \107\ Id.
---------------------------------------------------------------------------

    The commenters' claim that EPA's approval of Utah's Sec.  51.309
program in our December 2012 final action means that the State met its
reasonable progress requirements ``in its entirety'' is thus clearly
incorrect. In that action we determined that the State met the
requirements of Sec.  51.309 and therefore satisfied its reasonable
progress obligation with regard to the particular pollutants covered in
the State's alternative, i.e., SO2. This determination has
no bearing on the State's independent NOX and PM
obligations. To comply with the RHR, the state must still address any
BART obligations for pollutants not included in the BART alternative
analysis and therefore not covered by the ``better than BART''
determination.
    EPA similarly disagrees that it acknowledged that the
NOX controls in Utah's 2011 SIP submission are all that are
required to achieve reasonable progress and that EPA should therefore
not require further NOX BART requirements. As explained
earlier, EPA's determination that Utah's 2011 submission satisfied
reasonable progress requirements does not constitute implicit
evaluation and action on Utah's NOX and PM SIP submittal as
meeting the BART requirements. Furthermore, the commenter overlooks
EPA's explicit disapproval of Utah's NOX and PM BART
determinations in our December 2012 partial approval/disapproval.\108\
EPA's disapproval of Utah's NOX and PM control
determinations necessarily precludes finding that these same controls
are all that are required to satisfy the RHR's requirements. EPA is
thus required to promulgate a NOX BART FIP, which we are now
doing. Commenters also take EPA's statements regarding the quantity of
anticipated NOX reductions from Utah's rejected BART
determination out of context. These statements were offered as reasons
why Utah satisfied the RHR's requirement to address impacts on Class I
areas in other states by achieving previously agreed upon emission
reductions, which is a separate consideration from whether the State
has satisfied its independent NOX and PM BART obligations.
---------------------------------------------------------------------------

    \108\ 77 FR 74355, 74357 (Dec. 14, 2012).
---------------------------------------------------------------------------

    EPA also disagrees that the statements in the cited cases have any
bearing on this action. In Center for Energy and Economic Development
v. EPA (CEED),\109\ the issue was whether EPA's BART alternative
provisions in Sec.  51.309 were consistent with CAA section 169A(b)(2)
given that they used a methodology for establishing the BART benchmark
that the D.C. Circuit had previously vacated in American Corn Growers
Ass'n v. EPA.\110\ As part of its challenge to EPA's BART alternative
provisions, CEED argued that section 169A(b)(2) requires all states'
SIPs to include BART, meaning EPA could not allow BART alternatives in
place of source-specific BART. EPA argued that section 169A(b)(2)
allows either BART or an alternative to BART submitted pursuant to
Sec.  51.309 if that alternative would achieve greater reasonable
progress than BART, i.e., if the alternative is ``better than BART.''
The statements the commenter cites express EPA's view on the narrow
issue of whether and when we may allow states to substitute an
SO2 trading program for

source-specific BART under Sec.  51.309. Because these statements
address only the relationship between BART and BART alternatives for
SO2 under Sec.  51.309; they have no bearing on whether we
believe a state's submission of an SO2 trading program
satisfies its independent obligation to address NOX and PM,
as these obligations were not at issue in this case.
---------------------------------------------------------------------------

    \109\ 398 F.3d 653 (D.C. Cir. 2005).
    \110\ 291 F.3d 1 (D.C. Cir. 2002).
---------------------------------------------------------------------------

    In our December 14, 2012 action we approved Utah's BART Alternative
for SO2 under 40 CFR 51.309, finding that it achieved
greater reasonable progress than SO2 BART. As explained
earlier, this determination has no bearing on Utah's outstanding
NOX and PM BART obligations. We, therefore, disagree that
today's action to address these obligations is unnecessary.
    Comment: Several commenters asserted that Utah's BART Alternative
does not achieve greater reasonable progress based on the ``clear
weight-of-evidence.'' Utah's Regional Haze SIP also must be rejected
under 40 CFR 51.308(e)(2)(i)(E) because it does not achieve ``greater
reasonable progress'' based on the ``clear weight-of-evidence.'' \111\
---------------------------------------------------------------------------

    \111\ 40 CFR 51.308(e)(2)(i)(E).
---------------------------------------------------------------------------

    At the outset, Utah's proposed reliance on the ``clear weight-of-
evidence'' test is improper. In promulgating regulations allowing for
the test, 40 CFR 51.308(e)(2)(i)(E), offered the following example of
when the test might be appropriate: ``(1) The alternative program
achieves emissions reductions that are within the range believed
achievable from source-by-source BART at affected sources, (2) the
program imposes a firm cap on emissions that represents meaningful
reductions from current levels and, in contrast to BART, would prevent
emissions growth from new sources, and (3) the State is unable to
perform a sufficiently robust assessment of the programs using the two
pronged visibility test due to technical or data limitations.'' \112\
None of those conditions are met here. Most importantly, Utah's BART
Alternative does not drive any meaningful reductions from ``current
levels'' and does not prevent emissions growth from new sources, and
Utah is not hindered by any technical or data limitations preventing a
sufficiently robust visibility assessment. EPA further noted that ``a
weight-of-evidence comparison may be warranted'' ``when there is
confidence that the difference in visibility impacts between BART and
the alternative scenarios are expected to be large enough.'' \113\
Here, as EPA correctly observed, even Utah's flawed modeling
demonstrated the superiority of BART using the most relevant visibility
metric and only minimal benefits of the BART Alternative compared with
BART using other metrics.
---------------------------------------------------------------------------

    \112\ 71 FR 60612, 60621 (Oct. 13, 2006).
    \113\ Id. at 60622.
---------------------------------------------------------------------------

    Several commenters also raised concerns regarding emission shifting
from the power plants covered by the SIP to existing sources that are
not included in this SIP. They suggested that due to the nature of the
electrical generation market, with the adjustments to the overall
system to add capacity elsewhere to accommodate the Carbon power plant
shutdown (and perhaps also to accommodate the emission limit reductions
at the Hunter and Huntington power plants), those shifts in capacity
could result in increases in emissions at power plants outside the BART
Alternative. The commenters further suggested that if those emission
increases had been considered in the State's weight-of-evidence
analysis, the BART Alternative may not provide greater reasonable
progress than BART if the emission reductions assessment under the
Alternative are not permanent and were to shift to other power plants.
As an example, one of the commenters provided an analysis for a Utah
power plant (not covered by the BART Alternative) that based on its
proximity to the nine Class I areas analyzed under the BART
Alternative, if emission increases were to occur at that plant the
increases could impact visibility impairment at the Class I areas.
Other commenters expressed concern that the lost capacity from the BART
Alternative sources could shift to new sources, and explained that the
emissions from new sources are not evaluated in the State's weight-of-
evidence analysis. One commenter suggested that this Alternative
appears to be more like a ``trading'' program and that other
regulations apply. One commenter expressed concern that a non-BART
source is included in the BART Alternative, and further, that not all
the sources in the State that are part of this source category are
included.
    Response: We agree in part and disagree in part with these
comments. First, as explained elsewhere, we agree with the commenter
that the State's analysis for the BART Alternative does not show that
the Alternative clearly achieves greater visibility benefits than BART.
Second, the four examples cited by the commenter from our RHR preamble
were examples, rather than an exclusive list of circumstances under
which a state may use a weight-of-evidence analysis. Therefore, the
State was not required to fall into one of these categories in order to
select the weight-of-evidence approach to support its BART Alternative.
Third, we disagree that emission reductions must occur from current
levels, because, consistent with the RHR, the baseline date for
regional haze SIPs is 2002.\114\
---------------------------------------------------------------------------

    \114\ See Memorandum from Lydia Wegman and Peter Tsirigotis,
2002 Base Year Emission Inventory SIP Planning: 8-hr Ozone,
PM2.5, and Regional Haze Programs (November 18, 2002).
---------------------------------------------------------------------------

    Next we respond to the commenters' concerns about potential
shifting of production and emissions from the sources in the BART
Alternative to sources outside the BART Alternative. We acknowledge
that the State's BART Alternative has the following characteristics:
(1) It includes all the BART sources in the State; (2) it accounts for
emission reductions from a non-BART source; and (3) it includes some,
but not all, sources in the source category within the State. The RHR
provides that BART alternative programs may include non-BART
sources.\115\ We disagree with commenters that suggested the RHR
trading requirements apply to the Utah BART Alternative.\116\ The RHR
trading provisions apply to SIPs that establish a cap on total
emissions from sources that are subject to the BART program, and
further require the owners and operators of the sources to hold
allowances to purchase, sell, and transfer allowances. Utah's SIP
contains rate-based emission limits on the sources that are subject to
the BART Alternative and therefore does not include a cap on emissions
or trading provisions. Therefore, the Utah SIP does not contain the
elements of a trading program as described in the RHR, which include
provisions to prevent significant emission shifting.\117\
---------------------------------------------------------------------------

    \115\ The preamble to the RHR provides for inclusion of BART and
non-BART sources in a BART alternative. 64 FR 35714, 35743 (July 1,
1999).
    \116\ 40 CFR 51.308(e)(2)(E)(v) (containing requirements for a
state to demonstrate that a trading program prevent any significant,
potential shifting within the state of production and emissions from
the sources in the program to sources outside the program).
    \117\ Id.
---------------------------------------------------------------------------

    Although the State's SIP explained that the Carbon power plant had
already closed and electricity generated from the Carbon power plant
has been replaced (and the associated costs already have been absorbed
by Utah rate payers and those in other states served by
PacifiCorp),\118\ the SIP submittal neither identified what electrical
generating facilities increased capacity

to accommodate the Carbon shut down, nor did it provide an analysis of
whether the capacity replacement resulted in increases in visibility
impairing pollutants. Furthermore, in addition to seeking and receiving
authorization to recover costs associated with retirement of the Carbon
plant, the Company also received authorization from state utility
commissions to recover additional costs, including ``installation of
equipment necessary to ensure voltage stability, along with various
communications upgrades and protection and control equipment.'' \119\
It is unclear whether the activities associated with these additional
costs resulted in capacity and emissions shifting and increased
visibility impairment at the affected Class I areas. Therefore, while
the record before us indicates that capacity has shifted, it is unclear
how the shift was accommodated, and whether there are any emission
increases and associated visibility impairment.\120\
---------------------------------------------------------------------------

    \118\ Utah Staff Review Report at 27.
    \119\ The Application of Rocky Mountain Power for Approval of a
General Rate Increase, No. 20000-446-ER-14, Wyoming Public Service
Commission, (Jan. 23, 2015) (Findings of Fact, Conclusions of Law,
Decision and Order Nunc Pro Tunc) (Available in docket at https://www.regulations.gov/#!documentDetail;D=EPA-R08-OAR-2015-0463-0167).
An order from the Idaho Public Commission also discussed the impacts
from Carbon's retirement on the transmission system and noted that
``[t]he Company states that retiring Carbon may pose a complication
with potential transmission system impacts.'' See The Application of
PacifiCorp DBD DBA Rocky Mountain Power, Case No. PAC-E-12-08, Order
No. 32701, at 1, Idaho Public Utilities Commission (Dec. 27, 2012)
(Available in the docket at https://www.regulations.gov/#!documentDetail;D=EPA-R08-OAR-2015-0463-0167).
    \120\ Utah's BART Alternative has the characteristics of an
``open market'' program where some, but not all, sources in a source
category are covered by the SIP measure. EPA Guidance, ``Improving
Air Quality with Economic Incentive Programs,'' at 48, 96, 112-118,
EPA-452/R-01-001 (Jan. 2001), available at https://www3.epa.gov/ttn/caaa/t1/memoranda/eipfin.pdf); 77 FR 11928 (Feb. 28, 2012); 77 FR
46952 (Aug. 7, 2012).
---------------------------------------------------------------------------

    It is therefore unclear whether the shift in capacity as a result
of the Carbon plant retirement results in increased emissions and
visibility impairment at the affected Class I areas. Because the record
lacks information on these questions, we agree with the commenters that
there is additional uncertainty as to whether the BART Alternative is
better than BART.

E. Overarching Comments on BART Alternative Demonstration

    Comment: The State of Utah commented that EPA should approve the
option that Utah developed in close consultation with EPA and not the
option that Utah was not even aware was being prepared or under
consideration until it was signed by the Regional Administrator. Utah
worked closely and in good faith with the EPA and the FLMs to evaluate
and implement the appropriate controls for improving visibility. Up to
the point of the current proposal, the EPA has indicated to Utah that
the alternative to BART approach and analysis were acceptable. During
the RH SIP development process, Utah and EPA worked as regulatory
partners--Utah working closely and extensively with EPA's staff to
ensure that Utah's BART Alternative was approvable. EPA's concurrence
with Utah's RH SIP proposal is also supported by EPA's comments
submitted during the state rulemaking public comment period on the
current revision of the Utah's RH SIP. EPA did not point to any
substantive flaws in Utah's RH SIP, but only requested minor
clarifications and revisions in its 3-page comment letter.
    Response: While we agree that EPA worked in close consultation with
Utah on the BART Alternative within the limitations of what the State
and PacifiCorp were willing to offer in the plan, EPA is not required
to approve the option developed by Utah. As stated elsewhere in this
document, EPA's comment letter on the State's proposed SIP explicitly
explained the following: ``[p]lease note that we will only come to a
final conclusion regarding the regional haze program for Utah when we
take action on the program through our own public notice-and-comment
rulemaking.'' \121\ Our May 1, 2015 letter further explained to the
State that, ``[i]n addition, we wish to inform you that we are working
towards meeting our legal obligations that have resulted from our
January 2013 partial disapproval action for Utah's May 2011 regional
haze SIP.'' \122\ EPA's assistance to states and our comment letters
are intended to be helpful to the improvement of any SIP revision that
is under development, but they do not constitute agency action on that
SIP revision or constitute any assurance of positive action on that
revision upon submission and review.
---------------------------------------------------------------------------

    \121\ Letter from Carl Daly to Bryce Bird, Re. EPA Region 8
Comments on Utah's February 2015 Draft Regional Haze SIP Revision,
at 1 (May 1, 2015). (Available in the docket at https://www.regulations.gov/#!documentDetail;D=EPA-R08-OAR-2015-0463-0160).
    \122\ Id.
---------------------------------------------------------------------------

    Additionally, the State's efforts to involve the FLMs did not
adequately meet the requirements for FLM consultation in developing
plan revisions. The State could have satisfied the consultation
requirements by providing more time for FLM review so that the FLMs
would have received the full number of 60 days for their review.
However, in developing the co-proposals, consulting with the FLMs, and
by taking this final action, EPA has considered the FLMs' concerns.
    Comment: Several commenters asserted that both Utah and EPA imply
that nitrate formation in non-winter months is not significant,\123\ or
that NOX reductions will not meaningfully reduce nitrates in
non-winter months.\124\ Both are untrue. Based on IMPROVE data, light
extinction attributable to ammonium nitrate in non-winter months is
roughly 20% of that attributable to ammonium sulfate. Despite the
preferential formation of ammonium sulfate year round and higher
ammonium nitrate formation in winter months, it is clear that
significant levels of ammonium nitrate also form in non-winter months,
and that these are likely to be lowered by reductions in NOX
emissions. Furthermore, while EPA notes that wintertime conditions
favor nitrate formation (versus non-winter),\125\ this is accounted for
in modeling and cannot be used to discount those results.
---------------------------------------------------------------------------

    \123\ Utah Staff Review Report at 17, Exhibit 15. Winter months
in this context are December, January, and February.
    \124\ 81 FR 2004, 2023 (EPA says that based on a computational
model, ``We propose to find that visibility benefits associated with
NOX reductions are much more likely to occur in the
winter months because this is when aerosol thermodynamics favors
nitrate formation'').
    \125\ Id.
---------------------------------------------------------------------------

    Response: We partially agree with the comment. While EPA did not
suggest that nitrate in non-winter months is not significant, IMPROVE
monitoring data do show that nitrate light extinction is highest in
winter and substantially smaller in the other seasons. For example, in
2014, the most recent year of IMPROVE data available at the Canyonlands
monitor, nitrate contributed an average of 31% of total light
extinction in December to February compared to an average of 5% of
total light extinction from March to November. In 2013, nitrate
contributed an average of 45% of total light extinction in December to
February compared to an average of 7.5% of total light extinction from
March to November. By contrast, sulfate light extinction is relatively
constant across the four seasons.\126\
---------------------------------------------------------------------------

    \126\ See EPA spreadsheet entitled, Canyonlands IMPROVE
Monitoring Data for 2013 and 2014 (Available in the in the docket).
---------------------------------------------------------------------------

    Nonetheless, overall nitrate extinction at the affected areas is
significant, particularly on the 20% worst days. For example, at
Canyonlands on the 20% worst days, nitrate contributed 33% and 17% of
total extinction in 2013 and

2014, respectively. Given the focus of the reasonable progress
provisions of the RHR on the 20% worst days, we consider the monitoring
data for these days to be more informative than seasonal trends in
monitoring data.
    We also agree with the commenter that the modeling performed by
Utah and EPA accounts for the fact that wintertime conditions favor
nitrate formation (versus non-winter). In particular, the CALPUFF
modeling performed by Utah and EPA both show that, while there will be
some benefits from NOX controls outside of the winter
season, the largest benefits in nitrate reductions occur in winter
months.\127\ We have taken the strength of the modeling results for
winter months into consideration; however, contrary to suggestions that
visibility improvements during seasons of peak Class I area visitation
should carry more weight, we have evaluated the visibility impacts
throughout the entire year, regardless of the season and have given the
most weight to those times when the sources in question have the
largest impacts. In particular, as explained elsewhere in this document
and our RTC document, we have given greater weight to the 98th
percentile CALPUFF metric, which captures these highest impact days.
---------------------------------------------------------------------------

    \127\ Both Utah and EPA CALPUFF modeling results can be viewed
in or obtained from the EPA Region 8 offices by contacting the
individual listed in the FOR FURTHER INFORMATION CONTACT section of
this document.
---------------------------------------------------------------------------

F. Cost of Controls

    Comment: Several commenters submitted comments regarding the costs
to install SCR at the Hunter and Huntington BART EGUs. PacifiCorp
submitted a technical report developed by its consultant, Sargent &
Lundy, which criticized numerous aspects of EPA's cost analysis
developed by our contractor, Andover Technology Partners (ATP),
including catalyst volume, SCR design, project and process contingency
costs, and others. The conservation organizations' consultant reviewed
PacifiCorp's cost analyses from 2012 and 2014 and provided comments
about the validity of PacifiCorp's analyses. The National Park Service
supported EPA's cost estimates in the proposed rule and indicated the
estimates show that both the combined cost of LNB and SOFA plus SCR
(SCR + LNB/SOFA) and the incremental cost of adding SCR to LNB/SOFA are
cost-effective and represent BART. The conservation organizations also
supported EPA's cost estimates in the proposed rule.
    Response: EPA has provided a revised cost analysis to support our
final rulemaking. We again used Andover Technology Partners (ATP) for
conducting the analysis. We have carefully reviewed the analysis and
determined that it appropriately estimates the costs to install SCR at
Hunter and Huntington. Of particular note is that in our revised cost
analysis, EPA has accepted both the catalyst volume and SCR design
suggested by Sargent & Lundy. However, we continue to reject process
and project contingency costs and other costs that are double counted,
not permissible under the CCM, or are otherwise not justified. The
final Andover report and spreadsheet provide further details regarding
how each of these costs was addressed in the revised analysis
supporting this rulemaking.\128\ Also, in our RTC document, we have
addressed the specific comments concerning the capital costs that
Sargent & Lundy alleges that Andover incorrectly excluded from its
analysis, as well as all other comments regarding our cost estimates.
---------------------------------------------------------------------------

    \128\ Andover Technology Partners, Cost of NOX BART Controls on
Utah EGUs to: EC/R Inc. (May 13, 2016). Andover Technology Partners
is a subcontractor to EC/R Incorporated.
---------------------------------------------------------------------------

    We concur with the National Park Service's and conservation
organizations' supportive comments regarding the cost effectiveness of
SNCR and SCR. In addition, the revised cost effectiveness estimates
that we prepared to support this final rule, when considered along with
the other five BART factors, continue to support selection of SCR +
LNB/SOFA as BART.
    The conservation organizations' comments pertain to the costs that
PacifiCorp submitted to the Utah Department of Air Quality, and which
Utah included in its SIP submittal to EPA. However, EPA developed
separate costs to support our FIP, and has updated those costs in
support of our final action. Our RTC document contains additional
detail concerning our consideration of these comments.

G. Comparison With Other Regional Haze Actions

    Comment: Two commenters agreed with the comparisons we provided in
our proposed rule to other BART determinations that EPA used to support
our proposed FIP. One commenter disagreed with the comparisons. These
comparisons included Cholla,\129\ Hayden,\130\ and Laramie River
Station.\131\ The commenter who disagreed asserted that different
methodologies were involved in all three cases and that EPA failed to
provide comparisons to other actions that did not support the FIP. The
commenter provided additional examples from EPA actions in Florida,
Montana, and Nebraska that they asserted do not support EPA's Utah FIP
decision.
---------------------------------------------------------------------------

    \129\ 77 FR 42834 (July 20, 2012) (proposal); 77 FR 72512,
72514-15 (Dec. 5, 2012) (final).
    \130\ 77 FR 18069 (Mar. 26, 2012) (proposal); 77 FR 76871 (Dec.
31, 2012) (final).
    \131\ 79 FR 5032, 5099 (Jan. 30, 2014) (final partial approval/
partial disapproval of Wyoming regional haze SIP submission).
---------------------------------------------------------------------------

    Response: We continue to find that the Cholla, Hayden and Laramie
River Station comparisons are among the best to use considering the
specifics of our Utah action. The commenter who disagreed with these
comparisons did not show that it would make a significant difference to
use precisely the same methodology in each of the determinations that
EPA chose to rely on. Furthermore, we disagree that the methodology
involved in the BART analyses necessarily must be precisely the same
for each BART determination in order to use the determinations for
comparison purposes. For example, a state may choose to use a slightly
different methodology to analyze the BART factors and select BART,
which is acceptable so long as the methodology is reasonable and
consistent with the statute, RHR, and BART Guidelines. For details,
please see the RTC document.
    We also disagree that the cited BART determinations in Montana,
Florida, and Nebraska are useful comparisons or show that our BART
determination here is unreasonable. First, with respect to the Florida
action, the cited NOX BART determination at FPL's Manatee
Plant involved two 800 MW oil and natural-gas fired steam turbines. 77
FR 73369, 73377 (Dec. 10, 2012) (proposal). As the two units were
equipped with FGR, overfire air systems, staged combustion, LNB, and
reburn, SCR was the only available additional control option
identified. The total annualized cost of SCR at the two units would be
$31 million, from which the state computed a dollar-per-deciview cost
of $66 million/dv. Id. at 73377. Using these figures, the total (i.e.
source wide) visibility improvements at the most impacted Class I area,
Chassahowitzka NWA, would be 0.47 dv, which is considerably below the
source-wide visibility improvement for SCR + LNB/SOFA at Hunter and
Huntington of 2.948 dv and 3.848 dv, respectively.\132\

In addition, the Manatee Plant impacted only one other Class I area,
Everglades NP, at nearly twice the distance of Chassahowitzka NWA. In
comparison, Hunter and Huntington significantly impact nine Class I
areas. Furthermore, the Manatee Plant received a permit to increase
natural gas utilization from 5,670 MMBtu/hr to 8,650 MMBtu/hr, which
would displace the use of oil and provide additional NOX
reductions. All of these must be considered when examining the state's
conclusion that SCR would not be cost-effective for these units, which
was primarily based on the dollar-per-deciview cost of $66 million/dv
and not on the raw cost-effectiveness number of $3,776/ton. While we
are not basing our BART determinations on the dollar-per-deciview
metric, for purposes of comparison to Manatee, the dollar-per-deciview
cost for Hunter and Huntington would be considerably less than at
Manatee, about $23.7 million/dv and $15.8 million/dv, respectively, at
the most impacted Class I area, and as mentioned earlier Hunter and
Huntington impact many more Class I areas than Manatee.
---------------------------------------------------------------------------

    \132\ See also our response to comments on existing controls and
the baseline, in which we look at the cost and visibility benefits
at Hunter and Huntington of SCR apart from the LNB/SOFA, to show
that even if we agreed with this commenter that the baseline should
reflect the installation of LNB/SOFA--which we do not--the selection
of SCR as BART would still be reasonable. The numbers used there
also compare favorably with Manatee.
---------------------------------------------------------------------------

    With respect to the Montana action, EPA stated for PPL Colstrip
Units 1 and 2, ``we estimated the incremental cost effectiveness of SCR
+ SOFA (over SNCR + SOFA) to [be] $5,770/ton and $5,887/ton,
respectively. Given these costs, we continue to find that SCR + SOFA is
not justified by the visibility improvement that would be provided.''
77 FR 57864, 57889 (Sept. 18, 2012) (emphasis added). The commenter
omits the emphasized language. The visibility improvements for the
various NOX control options for Colstrip Units 1 and 2 can
be seen in our proposal action and in general are much lower than those
for Hunter and Huntington. See 77 FR 23988, 24026-27, 24034-35 (Apr.
20, 2012). In particular, at Colstrip Unit 1, the visibility
improvements from SCR + SOFA at the five impacted Class I areas (which
is less than the nine impacted by Hunter and Huntington) ranged from
0.081 to 0.404 dv. At Colstrip Unit 2, the visibility improvements from
SCR + SOFA at the same class I areas ranged from 0.091 dv to 0.423 dv.
These values are all much less than for the Hunter and Huntington BART
units. In any case, our NOX BART determinations for Colstrip
Units 1 and 2 were vacated by the Ninth Circuit Court of Appeals. Nat'l
Parks Conserv. Ass'n v. U.S. EPA, 788 F.3d 1134 (9th Cir. 2014).\133\
Finally, commenter's citation to the Nebraska proposal is fully
addressed by our response to a similar comment on our Wyoming regional
haze action. 79 FR 5032, 5178 (Jan. 30, 2014). Please refer to our RTC
document for additional discussion of our comparisons to other BART
determinations.
---------------------------------------------------------------------------

    \133\ The same commenter notes that the Wyoming and Arizona BART
determinations we used for comparison purposes are currently under
litigation; however the commenter fails to note that the Montana
BART determination they propose for comparison was actually
litigated and vacated. With respect to the pending litigation over
the Wyoming and Arizona BART determinations, there are other BART
determinations such as Colorado's Hayden Station that are
comparable, support our selection of SCR + LNB/SOFA, and are not
under litigation.
---------------------------------------------------------------------------

H. CALPUFF Modeling

    Comment: We received many comments related to both EPA's modeling
for the FIP and Utah's modeling for the BART Alternative. In
particular, PacifiCorp and its consultant asserted that EPA failed to
account for the margin of error in the CALPUFF model and other material
limitations of CALPUFF. PacifiCorp also asserted that we should have
used CALPUFF version 6.42 in our FIP analysis instead of version 5.8.4.
We partially respond to these comments here. Our full responses are
contained in our RTC document.
    Response: We do not agree with the commenter's criticism of the use
of CALPUFF. In promulgating the 2005 BART Guidelines, we responded to
comments concerning the limitations and appropriateness of using
CALPUFF. In 2005 we explained that CALPUFF is the only EPA-approved
model for use in estimating single source pollutant concentrations
resulting from the long range transport of primary pollutants. In
addition, it can also be used for other purposes such as visibility
assessments to account for the chemical transformations of
SO2 and NOX. As explained earlier, simulating the
effect of precursor pollutant emissions on PM2.5
concentrations requires air quality modeling that not only addresses
transport and diffusion, but also chemical transformations. CALPUFF
incorporates algorithms for predicting both. At a minimum, CALPUFF can
be used to estimate the relative impacts of BART-eligible sources. We
are confident that CALPUFF distinguishes, comparatively, the relative
contributions from sources such that the differences in source
configurations, sizes, emission rates, and visibility impacts are well-
reflected in the model results.\134\
---------------------------------------------------------------------------

    \134\ 70 FR 39122 (Jul. 6, 2005) (emphasis added).
---------------------------------------------------------------------------

    EPA also recognized the uncertainty in the CALPUFF modeling results
when EPA made the decision (in the final BART Guidelines) to recommend
that states use the 98th percentile visibility impairment rather than
the highest daily impact value. We made the decision to consider the
98th percentile primarily because the chemistry modules in the CALPUFF
model are simplified and likely to provide conservative (higher)
results for peak impacts. Since CALPUFF's simplified chemistry could
lead to model over predictions, EPA recommended the use of the 98th
percentile to avoid giving undue weight to the extreme tail of the
distribution.\135\ Therefore, in recognizing some of the limitations of
the CALPUFF model, we determined that use of the maximum modeled impact
may be overly conservative and recommended the use of the 98th
percentile value. While recognizing the limitations of the CALPUFF
model in the BART Guidelines preamble, EPA concluded that, for the
specific purposes of the RHR's BART provisions, CALPUFF is sufficiently
reliable to inform the decision making process.\136\
---------------------------------------------------------------------------

    \135\ ``Most important, the simplified chemistry in the model
tends to magnify the actual visibility effects of that source.
Because of these features and the uncertainties associated with the
model, we believe it is appropriate to use the 98th percentile--a
more robust approach that does not give undue weight to the extreme
tail of the distribution.'' 70 FR 39104, 39121 (Jul. 6, 2005).
    \136\ 70 FR 39123 (Jul. 6, 2005).
---------------------------------------------------------------------------

    It is further worth noting that the CALPUFF model can both predict
higher and lower visibility impacts compared to a photochemical grid
model. For example, the 2012 ENVIRON report on Comparison of Single-
Source Air Quality Assessment Techniques for Ozone, PM2.5, other
criteria pollutants and AQRVs found that CALPUFF's predictions of the
highest 24-hr nitrate and sulfate concentrations were lower than those
predicted by the CAMx photochemical grid model in some areas within the
modeling domain.\137\ Thus, while there is some uncertainty in the
absolute visibility impacts and benefits due to the model and some of
the simplifications and assumptions used in the BART Guidelines
modeling approach, the relative level of impact has been a reliable
assessment of the degree of visibility impacts and benefit from
controls. Any uncertainties in meteorological conditions that govern
the transport and diffusion of pollutants are less important in
comparing impacts between two control scenarios, since the

same effects will be included in both the base and the control scenario
model simulations.
---------------------------------------------------------------------------

    \137\ Comparison of Single-Source Air Quality Assessment
Techniques for Ozone, PM2.5, other Criteria Pollutants
and AQRVs, ENVIRON, September 2012.
---------------------------------------------------------------------------

    We also do not agree with the commenter's calculation of a ``margin
of error'' for CALPUFF. The notion of a calculated ``margin of error''
is not part of any modeling guidance and has no legal or regulatory
basis or applicability here. In addition, the commenter's suggestion
that a 2012 report titled ``Documentation of the Evaluation of CALPUFF
and Other Long Range Transport Models Using Tracer Field Experiment
Data'', EPA-454/R-12-003 (ENVIRON Report) establishes a standard
``margin of error'' for CALPUFF is unfounded. The ENVIRON Report
illustrated how well various types of modeling systems are able to
capture regional transport. It does not provide any information about
the accuracy of any models for predicting secondary PM2.5 or
visibility, nor does it indicate that the quantitative performance
results provided are a presumptive globally applicable ``margin of
error.'' Rather, these results are simply a way to compare various
modeling systems in terms of performance for skill in long range
transport. Thus, we do not agree that the ENVIRON Report provides a
presumptive margin of error that can be applied to the modeling results
in Utah's SIP or EPA's FIP.
    With regard to Utah's use of CALPUFF in its SIP revision
specifically, we note that the State was not required to use CALPUFF
for purposes of its BART Alternative Demonstration under 40 CFR
51.308(e)(2)(i). Utah or PacifiCorp could have used other EPA-approved
models with more advanced chemistry and dispersion techniques to
support the BART Alternative demonstration but chose not to do so.
    With regard to our use of CALPUFF for purposes of the FIP modeling,
as explained in more detail in our RTC document, the legal deadline for
challenging EPA's recommendation to use CALPUFF in BART analyses has
passed. Furthermore, although the EPA proposed revisions to 40 CFR part
51, appendix W, Guideline on Air Quality Models (``Guideline'') in
2015, these proposed changes to the Guideline do not affect our
recommendation in the 2005 BART Guidelines to use CALPUFF in the BART
determination process.\138\ Rather, as explained in the preamble to the
proposed Guideline revisions, we consider it appropriate to continue
using CALPUFF for BART determinations, given that the vast majority of
BART determinations have been made using CALPUFF.\139\
---------------------------------------------------------------------------

    \138\ 80 FR 45340, 45350 (July 29, 2015).
    \139\ Id.
---------------------------------------------------------------------------

    In particular, for our FIP modeling, we used the current EPA-
approved version of CALPUFF (Version 5.8.4, Level 130731). We disagree
with the commenters that a new CALPUFF version should be used for the
BART determinations. We relied on version 5.8 of CALPUFF because it is
the version approved by EPA through a public notice-and-comment
rulemaking, in accordance with the Guidelines (40 CFR part 51, appendix
W, section 6.2.1.e). Later versions of CALPUFF are not approved by EPA
for regulatory purposes, and we do not agree that the changes made to
this most recent version of CALPUFF were simple model updates to
address bugs. A full evaluation of a new model such as CALPUFF version
6.4 is needed before it should be used for regulatory purposes as
errors that are not immediately apparent can be introduced along with
new model features.
    In response to comments, EPA performed additional modeling analysis
to assess the combined benefit of SCR when applied to each of the two
BART units at the Hunter facility. We did the same for the Huntington
facility. These modeling results are shown in Tables 6 and 7 earlier in
this document. Otherwise, we did not receive any comments that
convinced us to alter our CALPUFF modeling analysis, and the comments
we received do not justify a change in our BART determinations or our
evaluation of the State's BART Alternative. We discuss these and other
modeling comments in detail in our RTC document.

I. Consideration of Existing Controls

    Comment: Several commenters asserted that EPA did not properly take
into account the existing pollution control technology in use at the
Hunter and Huntington BART units, as required by CAA section 169A(g)(2)
and the BART Guidelines. Two of these commenters alleged that EPA was
required to consider updated combustion controls, which were installed
to comply with Utah's regional haze SIP. The commenters said EPA
improperly used 2001-2003 emissions data to establish the baseline
emissions for the Utah BART Units and that this is neither realistic
nor provides the anticipated emissions as required by the BART
Guidelines. The commenters asserted that had EPA relied on more recent
emissions data, which reflect the NOX reductions achieved by
some of these newly installed controls, the cost-effectiveness values
for SCR would have been higher, while the visibility improvement
associated with SCR would have been lower.
    Commenters pointed to an 8th Circuit court decision on EPA's final
action on the North Dakota regional haze SIP where the Court found that
EPA had failed to properly consider the existing pollution control
technology at the Coal Creek Station. Commenters also asserted that in
other EPA regional haze actions, EPA had adjusted baseline emissions to
account for recently installed controls, such as EPA's final actions on
the Arizona and Colorado regional haze SIPs, and settlement agreement
with EPA Region 8 for the Deseret Bonanza plant. This commenter argued
that because EPA had adjusted baseline emissions for some Arizona and
Colorado EGUs to account for controls recently installed to satisfy
consent decrees obligations or CAA requirements unrelated to regional
haze, EPA was required to do so for Utah's EGUs as well.
    Two final commenters submitted supportive comments regarding the
need for using a standard baseline period to provide for greater
national consistency. One of these commenters noted examples where EPA
has evaluated NOX BART based on a baseline period from
before the installation of the pollution controls, for the Navajo
regional haze plan and the Wyoming regional haze plan.
    Response: We disagree with comments that EPA failed to consider or
unreasonably considered the existing pollution control technology at
the Hunter and Huntington BART units. One of the statutory factors EPA
is to consider for BART is ``any existing pollution control technology
in use at the source.'' 42 U.S.C. 7491(g)(2). The CAA and the BART
Guidelines do not specify how states or EPA must ``take into
consideration'' this factor. Nor did the Eighth Circuit Court of
Appeals specify how existing controls must be taken into account;
instead it only examined the meaning of the word ``any,'' holding that
EPA misinterpreted the term. North Dakota v. U.S. EPA, 730 F.3d 750,
762-64 (8th Cir. 2013). The Court did not examine the meaning of the
phrase ``take into consideration.'' See id. As the statute is silent on
how to take into consideration existing controls, under Chevron U.S.A.
v. NRDC, 467 U.S. 837, 843-44 (1984), this silence creates a gap for
EPA to fill. As next summarized and detailed in our RTC document, we
are reasonably considering existing controls in several ways.

    First, the BART Guidelines state that existing pollution control
technology in use at the source affects the availability of control
options and their impacts. 40 CFR part 51, appendix Y, at IV.A. The
Guidelines go on to explain that ``[f]or emission units subject to a
BART review, there will often be control measures or devices already in
place. For such emission units, it is important to include control
options that involve improvements to existing controls and not to limit
the control options only to those measures that involve a complete
replacement of control devices.'' 40 CFR part 51, appendix Y, at
IV.D.1.6. We have followed this recommendation. We find that the
existing combustion controls, LNB/SOFA, cannot be reasonably upgraded,
and we are not considering a control option that involves their
complete replacement. The post-combustion control options, SNCR and
SCR, by their nature can operate independently of combustion controls
and without changes to the combustion controls, another way in which we
considered the existing controls when evaluating SNCR and SCR.
    Consistent with the Guidelines' statement that existing pollution
control equipment in use at the source affects the impacts of the
control options, we used the sources' current NOX emission
rates when we evaluated the size, design, and reagent/catalyst cost of
SNCR and SCR. For example, in the case of Hunter Unit 1, we did not use
the baseline emission rate of 0.40 lb/MMBtu, but rather the current
emission rate of 0.21 lb/MMBtu that appropriately reflects the
installation of LNB/SOFA. Due to the lower NOX emission
rate, the size of the SNCR and SCR systems and the amount of reagent/
catalyst necessary to operate them are lower than if we had simply
assumed the baseline emission rate. This is a reasonable way in which
to consider existing pollution control technology.
    As discussed in our Wyoming action and in additional detail in our
RTC document for this action, baseline emissions should be ``a
realistic depiction of anticipated annual emissions'' before the
installation of BART. 40 CFR part 51, appendix Y, at IV.D.4.d. Because
the LNB/OFA were installed pursuant to Utah's proposed BART
determination, we used the period 2001-2003, prior to the installation
of LNB/OFA at the Hunter and Huntington BART units, for baseline
emissions, which in turn we used to evaluate the cost-effectiveness and
visibility of control options. As a result, the existing LNB/OFA were
not included in the baseline. According to the commenter, this skewed
EPA's analysis.
    We disagree. Because we have also considered the existing controls
in our final BART determination by examining the cost-effectiveness and
visibility benefit of SNCR and SCR relative to the existing LNB/SOFA as
well as in tandem with LNB/SOFA, we have avoided any possibility that
exclusion of the LNB/OFA from the baseline could result in an
unreasonable BART selection. The cost-effectiveness values of SCR and
SNCR relative to the existing LNB/SOFA are presented in the per-unit
tables for Hunter and Huntington (Tables 2-5) under ``Incremental cost-
effectiveness.'' In other words, the cost-effectiveness value for SCR
alone (assuming the existing LNB/SOFA) is essentially the same as the
incremental cost-effectiveness of SCR + LNB/SOFA as compared to LNB/
SOFA that is presented in the tables. As can be seen, the incremental
cost-effectiveness values of SCR + LNB/SOFA relative to LNB/SOFA are,
for all four units, somewhat lower than the incremental cost-
effectiveness of SCR relative to SNCR. As explained in the section
giving the rationale for our final action, we find the incremental
cost-effectiveness of SCR to be reasonable relative to SNCR; therefore
it is also reasonable relative to the existing LNB/SOFA.
    Another way to make the same point is to, for the sake of argument,
accept (which we do not) commenter's position that the baseline should
reflect the LNB/SOFA. In that case, the values in the tables for the
incremental cost-effectiveness of SCR + LNB/SOFA relative to LNB/SOFA
can serve as a proxy for the average cost-effectiveness of SCR
(assuming LNB/SOFA in the baseline). As shown by our comparisons, the
incremental cost-effectiveness of SCR + LNB/SOFA is generally
reasonable given the visibility benefits. This in turn shows that, even
accepting for the sake of argument that LNB/SOFA should be reflected in
the baseline, the average cost-effectiveness of SCR remains reasonable.
Similar considerations apply to the incremental visibility benefits of
SCR + LNB/SOFA relative to LNB/SOFA, which can be used as a proxy for
the visibility benefits of SCR alone assuming that LNB/SOFA are
reflected in the baseline. As shown by our comparisons, the incremental
visibility benefits of SCR + LNB/SOFA relative to SNCR + LNB/SOFA are
substantial and justify the costs of SCR. Since the incremental
visibility benefits of SCR + LNB/SOFA relative to LNB/SOFA are
necessarily larger than the incremental benefits relative to SNCR +
LNB/SOFA, the incremental visibility benefits of SCR + LNB/SOFA
relative to LNB/SOFA will also justify the costs of SCR. This in turn
shows that even if we accepted the commenter's position--which we do
not--the visibility benefits of SCR would justify its selection. For
our detailed responses, please see our RTC document.
    Finally, we acknowledge the supportive comments from two commenters
on this issue and agree with many of the points that were made, for
reasons explained elsewhere in this document and in our RTC document.

J. PM10 BART

    Comment: We received several minor comments on Utah's
PM10 BART determinations. One commenter in particular
asserted that Utah underestimated the control effectiveness of
baghouses, which should be able to achieve a limit of 0.010 lb/MMBtu or
even lower.
    Response: EPA agrees that baghouses have very high PM control
efficiency capabilities. However, due to the low contribution of direct
PM emissions from point sources such as Hunter Units 1 and 2 and
Huntington Units 1 and 2 \140\ to visibility impairment and,
consequently, the low anticipated visibility benefits from small PM
reductions, lowering the emission limit to 0.010 is unlikely to result
in any meaningful visibility improvement. We agree with Utah that the
existing PM10 emission limit adopted for these sources in
Section IX, Part H.22 of Utah's SIP satisfies BART for these units. We
are finalizing our approval of Utah's PM10 BART
determination at Hunter Units 1 and 2 and Huntington Units 1 and 2. We
find that an emission limit of 0.015 lb/MMBtu represents what can be
continuously achieved with a properly operated baghouse on these units.
The fabric filters (i.e., baghouses) at Hunter and Huntington are all
new since they were installed after 2008. Recent PSD BACT limits for
coal-fired EGUs with new baghouses have typically ranged from 0.01 to
0.015 lb/MMBtu using Method 5.
---------------------------------------------------------------------------

    \140\ See Western Regional Air Partnership Regional Haze Rule
Reasonable Progress Summary Report, Air Resource Specialist, Inc.,
State and Class I Area Summaries, Appendix p. 6-29, Table 6.13-19
(June 28, 2013). Available in the docket and at http://www.wrapair2.org/RHRPR.aspx.
---------------------------------------------------------------------------

    In addition, we note that the latest revision to the EGU New Source
Performance Standards (NSPS) requires modified units to meet a PM limit
of 0.015 lb/MMBtu.\141\ Also, the EGU MATS rule set a PM emissions
standard

of 0.03 lb/MMBtu as MACT for existing EGUs, and the BART Guidelines
provide that, ``unless there are new technologies subsequent to the
MACT standards which would lead to cost-effective increases in the
level of control, you may rely on the MACT standards for purposes of
BART.'' \142\ Therefore, we are finalizing our proposed approval of
Utah's BART determination for PM10 at Hunter Units 1 and 2
and Huntington Units 1 and 2.
---------------------------------------------------------------------------

    \141\ 77 FR 9450 (Feb. 16, 2012) (codified at 40 CFR 60.42Da).
    \142\ 40 CFR part 51, appendix Y, section IV.C. While the
Supreme Court reversed the D.C. Circuit's judgment on the MATS rule,
the Supreme Court did so based on EPA's approach to the
``appropriate and necessary'' finding, not EPA's determination of
MACT for EGUs. Michigan v. EPA, 135 S. Ct. 2699 (2015).
---------------------------------------------------------------------------

K. Environmental Justice

    Comment: One commenter requested that EPA's FIP address any
disproportionately high and adverse human health, economic, and
environmental impacts on minority and low-income communities in Utah
due to the regional haze plan. The commenter noted that this may be
accomplished consistent with federal Executive Order 12898, which
establishes environmental justice policy. The commenter also noted that
societal costs such as general public health costs associated with poor
air quality should be considered in the environmental justice analysis.
    Response: In making a final determination in this case, EPA
considered Executive Order 12898, which establishes federal executive
policy on environmental justice. This Executive Order directs federal
agencies, to the greatest extent practicable and permitted by law, to
make environmental justice part of their mission by identifying and
addressing, as appropriate, disproportionately high and adverse human
health or environmental effects of their programs, policies, and
activities on minority populations and low-income populations in the
United States. EPA has determined that this final rule will not have
disproportionately high and adverse human health or environmental
effects on minority or low-income populations. The installation of SCR
at the two facilities will ensure greater emissions reductions of
NOX resulting in overall increases in the level of
environmental protection for all affected populations.
    EPA disagrees with the comment that societal costs such as general
public health costs associated with poor air quality should be
considered in the environmental justice analysis for this action. As
addressed elsewhere in our RTC document, neither section 169A of the
CAA, nor the BART Guidelines, require the BART analysis to include or
quantify benefits to health, as health impacts are appropriately
addressed under other CAA programs. Moreover, an analysis of societal
costs is unlikely to alter the impact relating to environmental justice
concerns because the final rule will result in greater protection for
all affected populations as a result of the installation of the most
stringent control technology available for NOX.

III. Final Action

    For the reasons discussed more fully in sections I and II and
detailed in our proposal and its accompanying supporting materials, in
this action, we are partially approving and partially disapproving
revisions to the Utah SIP submitted by the State of Utah on June 4,
2015. We are taking no action on the Utah SIP submittal of October 20,
2015.
    Section 110(k)(3) of the Act addresses the situation in which an
entire submittal, or a separable portion of a submittal, meets all
applicable requirements of the Act. In the case where a separable
portion of the submittal meets all the applicable requirements, partial
approval may be used to approve that part of the submittal and
disapprove the remainder. Since the portions of the regional haze SIP
submittal we are approving are separable from the portions we are
disapproving as explained earlier, each approved PM10 BART
determination for a particular pollutant for a given source will have
an enforceable date of five years from the date of EPA's approval.
    Under section 110(k)(4) of the Act, EPA may approve a submittal
based on a commitment of the State to adopt specific enforceable
measures no later than one year after the date of approval of the
submittal. We are conditionally approving the State's recordkeeping
requirements for the PM BART emission limitations based on Utah's
commitment to adopt and submit certain measures to address the
deficiencies in the recordkeeping requirements. If the State fails to
adopt and submit these measures within one year of this action, our
conditional approval will be treated as a disapproval.
    Under section 110(c)(1)(B) of the Act, within two years of
disapproving a required submittal in whole or in part, EPA must
promulgate a FIP to address the deficiencies, unless the State corrects
the deficiencies through a submittal and EPA approves the submittal
before we promulgate a FIP. As a result of our prior disapproval of
Utah's PM and NOX BART submittals in 2012, there was a
pending obligation for EPA to promulgate a FIP for PM and
NOX BART. In this action, we are promulgating a FIP for
NOX BART. Because we are approving Utah's revised PM BART
submittal, which corrects the previous deficiencies in the original PM
BART submittal, there is no longer an obligation for EPA to promulgate
a FIP for PM BART. Thus, EPA has discharged its FIP obligations with
respect to PM and NOX BART for the State of Utah.

A. Final Partial Approval

    1. We are approving these elements of the State's SIP submittals,
which rely on elements from prior approvals: \143\
---------------------------------------------------------------------------

    \143\ As necessary for our approval, we are filling gaps in the
2015 Utah regional haze RH SIP submittals with the following
already-approved sections from the 2011 Utah RH SIP: Section XX.B.8,
Figures 1 and 2, Affected Class I Areas, pp. 8-9; Section XX.D.6.b,
Table 3, BART-Eligible Sources in Utah, p. 21; Section. XX.D.6.c,
Sources Subject to BART, pp. 21-23.
---------------------------------------------------------------------------

     BART determinations and emission limits for
PM10 at Hunter Units 1 and 2 and Huntington Units 1 and 2.
     Monitoring, recordkeeping, and reporting requirements for
units subject to the PM10 emission limits, including
conditional approval of the recordkeeping requirements for the
PM10 emission limits.

B. Final Partial Disapproval and Federal Implementation Plan

    1. We are disapproving these aspects of the State's June 4, 2015
SIP submittal:
     NOX BART Alternative that includes
NOX, and SO2 emission reductions from Hunter
Units 1 through 3, Huntington 1 and 2, and Carbon Units 1 and 2, and
PM10 emission reductions from Carbon Units 1 and 2.
     Monitoring, recordkeeping and reporting requirements for
units subject to the BART Alternative.
    2. We are promulgating a FIP to address the deficiencies in the
Utah regional haze SIP. The FIP includes the following elements:
     NOX BART determinations and limits for Hunter
Units 1 and 2, Huntington Units 1 and 2.
     Monitoring, recordkeeping, and reporting requirements
applicable to Hunter Units 1 and 2, and Huntington Units 1 and 2.

C. No Action

    1. We are taking no action on the State's October 20, 2015 SIP
submittal which includes the following:
     The enforceable commitments to revise, at a minimum, SIP
Section XX.D.3.c and State rule R307-150 by March 2018.

IV. 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 Utah
Administrative Code discussed in section III, Final Action of this
preamble. The EPA has made, and will continue to make, these documents
generally available electronically through www.regulations.gov and/or
in hard copy at the appropriate EPA office (see the ADDRESSES section
of this preamble for more information).

V. Statutory and Executive Order Reviews

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

    This action is exempt from review by the Office of Management and
Budget (OMB) because this final rule applies to only two facilities
containing four BART units. It is therefore not a rule of general
applicability.

B. Paperwork Reduction Act

    This action does not impose an information collection burden under
the provisions of the Paperwork Reduction Act (PRA).\144\ Because this
final rule applies to just two facilities, the PRA does not apply.
---------------------------------------------------------------------------

    \144\ 44 U.S.C. 3501 et seq.
---------------------------------------------------------------------------

C. Regulatory Flexibility Act

    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.
    EPA is partially disapproving the State's SIP submittal and
promulgating a FIP that consists of imposing federal controls to meet
the BART requirement for emissions on four specific BART units at two
facilities in Utah. The net result of this action is that EPA is
requiring direct emission controls on selected units at only two
sources, and those sources are large electric generating plants that
are not owned by small entities, and therefore the owners are not a
small entities under the RFA.

D. 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.
    EPA has determined that Title II of the UMRA does not apply to this
rule. In 2 U.S.C. 1502(1) all terms in Title II of UMRA have the
meanings set forth in 2 U.S.C. 658, which further provides that the
terms ``regulation'' and ``rule'' have the meanings set forth in 5
U.S.C. 601(2). Under 5 U.S.C. 601(2), ``the term `rule' does not
include a rule of particular applicability relating to . . .
facilities.'' Because this rule is a rule of particular applicability
relating to all four BART units at the Hunter and Huntington plants,
EPA has determined that it is not a ``rule'' for the purposes of Title
II of the UMRA. The private sector expenditures that result from
promulgating a FIP include BART controls for all four units at the
Hunter and Huntington plants are $58.6 million \145\ per year.
Additionally, we do not foresee significant costs (if any) for state
and local governments. Thus, because the annual expenditures associated
with promulgating a FIP are less than the threshold of $100 million in
any one year, this final rule is not subject to the requirements of
sections 202 or 205 of UMRA. This final rule is also not subject to the
requirements of section 203 of UMRA because it contains no regulatory
requirements that might significantly or uniquely affect small
governments.
---------------------------------------------------------------------------

    \145\ Andover Technology Partners, Cost of NOX BART Controls on
Utah EGUs, to EC/R, Inc. (May 13, 2016). Andover Technology Partners
is a subcontractor to EC/R Incorporated.
---------------------------------------------------------------------------

E. 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.

F. 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
tribal governments. Thus, Executive Order 13175 does not apply to this
action.

G. 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 environmental 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 the EPA does not believe the
environmental health or safety risks addressed by this action present a
disproportionate risk to children. Moreover, ``regulation'' or
``rule,'' is defined in Executive Order 12866 as ``an agency statement
of general applicability and future effect.'' E.O. 12866 does not
define ``statement of general applicability,'' but this term commonly
refers to statements that apply to groups or classes, as opposed to
statements, which apply only to named entities. The FIP therefore is
not a rule of general applicability because its requirements apply and
are tailored to only the Hunter and Huntington plants, which are
individually identified facilities. Thus, it is not a ``rule'' or
``regulation'' within the meaning of E.O. 12866. However, as this
action will limit emissions of NOX, it will have a
beneficial effect on children's health by reducing air pollution.

H. 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.

I. National Technology Transfer and Advancement Act

    This rulemaking does not involve technical standards.

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

    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 within the docket
in a document entitled ``Environmental Justice Analysis, November
2015.'' This final rule will result in overall emission reductions for
NOX, and PM10 and therefore an increase in the
level of environmental protection for all affected populations.

K. Congressional Review Act

    This action is not subject to the CRA because this is a rule of
particular applicability. Additionally, this action

is not a ``major rule'' as defined by 5 U.S.C. 804(2).

L. Judicial Review

    Under section 307(b)(1) of the CAA, petitions for judicial review
of this action must be filed in the United States Court of Appeals for
the appropriate circuit by September 6, 2016. Pursuant to CAA section
307(d)(1)(B), this action is subject to the requirements of CAA section
307(d) as it promulgates a FIP under CAA section 110(c). Filing a
petition for reconsideration by the Administrator of this final rule
does not affect the finality of this action for the purposes of
judicial review nor does it extend the time within which a petition for
judicial review may be filed, and shall not postpone the effectiveness
of such rule or action. This action may not be challenged later in
proceedings to enforce its requirements. See CAA section 307(b)(2).

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

List of Subjects in 40 CFR Part 52

    Environmental protection, Air pollution control, Incorporation by
reference, Intergovernmental relations, Nitrogen dioxide, Particulate
matter, Sulfur oxides.

    Dated: June 1, 2016.
Gina McCarthy,
Administrator.
    40 CFR part 52 is amended as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

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

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

Subpart TT--Utah

0
2. Section 52.2320 is amended by:
0
a. In the table in paragraph (c), under the heading ``R307-110. General
Requirements: State Implementation Plan'' revising the entry ``R307-
110-17.''
0
b. In the table in paragraph (e), under the heading ``XVII. Visibility
Protection'' adding in numerical order the entry ``Section XX.D.6. Best
Available Retrofit Technology (BART) Assessment for NOX and
PM''.
    The revision and addition read as follows:

Sec.  52.2320  Identification of plan.

* * * * *
    (c) * * *

----------------------------------------------------------------------------------------------------------------
                                                             State           Final rule
             Rule No.                   Rule title      effective date     citation, date          Comments
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
                            R307-110. General Requirements: State Implementation Plan
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
R307-110-17......................  Section IX. Control        6/4/2015  [Insert Federal      Except for Section
                                    Measures for Area                    Register citation]   IX.H.21.e. which
                                    and Point Sources,                   7/5/2016.            is conditionally
                                    Part H, Emissions                                         approved through
                                    Limits.                                                   one year from
                                                                                [Insert date of
                                                                                publication in the
                                                                                Federal Register],
                                                                                IX.H.21.g.,
                                                                                Sections of
                                                                                IX.H.21 that
                                                                                reference and
                                                                                apply to the
                                                                                source specific
                                                                                emission
                                                                                limitations
                                                                                disapproved in
                                                                                Section IX.H.22,
                                                                                and Sections
                                                                                IX.H.22.a.ii-iii,
                                                                                IX.H.22.b.ii, and
                                                                                IX.H.22.c.
----------------------------------------------------------------------------------------------------------------

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

* * * * *
    (e) * * *

----------------------------------------------------------------------------------------------------------------
                                               State
               Rule title                 effective date   Final rule citation, date           Comments
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
XVII. Visibility Protection
----------------------------------------------------------------------------------------------------------------

                                                  * * * * * * *
----------------------------------------------------------------------------------------------------------------
Section XX.D.6. Best Available Retrofit         6/4/2015  [Insert Federal Register    Except for XX.D.6.a the
 Technology (BART) Assessment for NOX                      citation] 7/5/2016.         phrase ``and BART for NOX
 and PM.                                                                               through alternative
                                                                                measures under 40 CFR
                                                                                51.308(e)(2)''; XX.D.6.c;
                                                                                XX.D.6.d the phrase ``NOX
                                                                                and'' in the first
                                                                                sentence, the entire last
                                                                                sentence in the
                                                                                introductory paragraph,
                                                                                all SO2 and NOX
                                                                                provisions and the word
                                                                                ``Permitted'' in the
                                                                                ``Utah Permitted Limits''
                                                                                column in Table 5,
                                                                                ``Hunter 3'' and the
                                                                                Hunter limits, and all
                                                                                provisions in the
                                                                                ``Presumptive BART
                                                                                Rates'' column in Table
                                                                                5; XX.D.6.e the phrase
                                                                                ``, and pursuant to
                                                                                51.308(e)(2)(E)(3) all
                                                                                alternative measures must
                                                                                take place within the
                                                                                first planning period'',
                                                                                the rows beginning with
                                                                                ``Hunter 3'', ``Carbon
                                                                                1'' and ``Carbon 2'' in
                                                                                Table 6, and the entire
                                                                                paragraph immediately
                                                                                following Table 6.
----------------------------------------------------------------------------------------------------------------

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

0
3. Section 52.2336 is added to read as follows:

Sec.  52.2336  Federal implementation plan for regional haze.

    (a) Applicability. (1) This section applies to each owner and
operator of the following emissions units in the State of Utah:
    (i) PacifiCorp Hunter Plant Units 1 and 2; and
    (ii) PacifiCorp Huntington Plant Units 1 and 2.
    (2) [Reserved]
    (b) Definitions. Terms not defined in this paragraph (b) shall have
the meaning given them in the Clean Air Act or EPA's regulations