 United States Court of Appeals
         FOR THE DISTRICT OF COLUMBIA CIRCUIT



Argued November 16, 2017              Decided March 20, 2018

                        No. 12-1342

             UTILITY AIR REGULATORY GROUP,
                       PETITIONER

                              v.

           ENVIRONMENTAL PROTECTION AGENCY,
                     RESPONDENT

   NATIONAL PARKS CONSERVATION ASSOCIATION, ET AL.,
                    INTERVENORS


   Consolidated with 12-1343, 12-1344, 12-1425, 12-1480,
   13-1003, 13-1045, 13-1129, 13-1178, 13-1179, 13-1180


       On Petitions for Review of Final Action of the
       United States Environmental Protection Agency


    Charles McPhedran argued the cause for Conservation
Group petitioners. With him on the briefs were David S. Baron
and Timothy D. Ballo. Thomas Cmar and Abigail M. Dillen
entered appearances.

    Norman W. Fichthorn, Aaron M. Flynn, Ken Paxton,
Attorney General, Office of the Attorney General for the State
of Texas, Priscilla M. Hubenak, Assistant Attorney General,
                               2

Herman Robinson, Donald Trahan, Dwana King, Jackie
Marve, Spencer Bowman, P. Stephen Gidiere, III, Thomas L.
Casey, III, David W. Mitchell, C. Frederick Beckner, III,
Stephanie Z. Moore, and Daniel J. Kelly were on the joint briefs
for State and Industry petitioners.      Courtney Burdette,
Charlotte Goudeau, Peter D. Keisler, Elliott B. Vega, Mark L.
Walters, Timothy K. Webster, and Kathy M. Wright entered
appearances.

    Norman L. Rave, Jr., Attorney, U.S. Department of Justice,
argued the cause and filed the brief for respondent. David A.
Carson, Senior Counsel, Jessica O’Donnell and Martin F.
McDermott, Attorneys, entered appearances.

    Charles McPhedran argued the cause for Conservation
Group intervenor-respondents. With him on the briefs were
David S. Baron and Timothy D. Ballo. Thomas Cmar and
Abigail M. Dillen entered appearances.

     Norman W. Fichthorn, Aaron M. Flynn, Curtis T. Hill, Jr.,
Attorney General, Office of the Attorney General for the State
of Indiana, Thomas M. Fisher, Solicitor General, Margaret
Claiborne Campbell, Hahnah Williams, Renee Cipriano, J.
Michael Showalter, David M. Flannery, Kathy G. Beckett,
Edward L. Kropp, P. Stephen Gidiere, III, Thomas L. Casey,
III, David W. Mitchell, C. Frederick Beckner, III, Stephanie Z.
Moore, and Daniel J. Kelly were on the brief for State and
Industry intervenor-respondents. Peter D. Keisler, Byron W.
Kirkpatrick, and Timothy K. Webster entered appearances.

   Before: GRIFFITH and PILLARD, Circuit Judges, and
WILLIAMS, Senior Circuit Judge.

   Opinion for the Court filed by Senior Circuit Judge
WILLIAMS.
                               3

     WILLIAMS, Senior Circuit Judge: On June 7, 2012 the
Environmental Protection Agency issued another rule in a long
succession of actions implementing Congress’s effort to restore
air quality and visibility in certain national parks and
wilderness areas (“Class I areas”) to what they would be under
natural conditions. Regional Haze: Revisions to Provisions
Governing Alternatives to Source-Specific Best Available
Retrofit Technology (BART) Determinations, Limited SIP
Disapprovals, and Federal Implementation Plans, 77 Fed. Reg.
33,642 (June 7, 2012) (“Final Rule”). In the rule, EPA took a
step in the implementation of its Cross-State Air Pollution
Rule, 76 Fed. Reg. 48,208 (Aug. 8, 2011) (“CSAPR”)
(pronounced by counsel as if the S and the A were reversed,
making it approximately “CASPER”). Specifically it amended
its Regional Haze Regulations and Guidelines for Best
Available Retrofit Technology (BART) Determinations, 70
Fed. Reg. 39,104 (July 6, 2005) (“Regional Haze Rule”), to
specify that CSAPR’s requirements were stringent and
effective enough for it to serve as a better-than-BART
alternative for states participating in CSAPR, thus excusing
states from compliance with BART itself.              40 C.F.R.
§ 51.308(e)(2), (e)(4). In the Final Rule EPA also disapproved
portions of certain State Implementation Plans (“SIPs”)
designed to achieve reasonable progress under the Regional
Haze Rule because those plans relied on a soon-to-be-defunct
predecessor of CSAPR, the Clean Air Interstate Rule, 70 Fed.
Reg. 25,162 (May 12, 2005) (“CAIR”). Instead, EPA
promulgated Federal Implementation Plans to address haze
levels in the disapproved states until those states could submit
approvable SIPs that relied on CSAPR (if those states were
among those eligible to rely on CSAPR) or otherwise
demonstrated a local alternative better than BART. 77 Fed.
Reg. at 33,653–54.

     The National Parks Conservation Association and the
Sierra Club (“conservation petitioners”) challenge the portion
                                 4

of the Final Rule allowing states to treat CSAPR compliance as
a better-than-BART alternative. Multiple power companies
and the Utility Air Regulatory Group, as well as the State of
Texas and the Louisiana Department of Environmental Quality
(“state and industry petitioners”) challenge EPA’s disapproval
of SIPs relying on CAIR as a better-than-BART alternative.
Except to the extent that the challenges are moot, we affirm
EPA’s actions.

                              * * *

     The Regional Haze Rule requires states to impose best
available retrofit technology (“BART”) on certain stationary
pollution sources—usually electric generation plants—
installed before August 1977.            40 C.F.R. §§ 51.301,
51.308(e)(1)(ii). The Rule allows states to pursue alternative
approaches, including EPA-approved regional approaches to
capping and trading emissions, to reduce haze if those
approaches meet EPA’s regulatory definition of being “better-
than-BART.” 40 C.F.R. § 51.308(e)(2); see Center for Energy
and Economic Development v. EPA, 398 F.3d 653, 660 (D.C.
Cir. 2005) (“CEED”) (affirming EPA’s discretion to approve
regional alternatives to BART so long as the discretion is
“rationally exercise[d]”). In Utility Air Regulatory Group v.
EPA, 471 F.3d 1333, 1335 (D.C. Cir. 2006) (“UARG I”), we
affirmed EPA’s finding that states could rely on CAIR as a
better-than-BART alternative against certain challenges raised
by industry and environmental petitioners. But in response to
a set of separate petitions by several states and electric utilities
we later found “more than several fatal flaws” in CAIR itself,
and because EPA had “adopted the rule as one, integral action,”
we vacated and remanded the rule in its entirety. North
Carolina v. EPA, 531 F.3d 896, 901 (D.C. Cir. 2008) (“North
Carolina I”). On rehearing, we remanded CAIR to EPA
without vacatur, convinced that, “notwithstanding the relative
flaws of CAIR, allowing CAIR to remain in effect until it is
                              5

replaced by a rule consistent with our opinion would at least
temporarily preserve the environmental values covered by
CAIR.” North Carolina v. EPA, 550 F.3d 1176, 1178 (D.C.
Cir. 2008) (“North Carolina II”). To replace CAIR, EPA
crafted and promulgated CSAPR, a revised regional sulfur
dioxide and nitrogen oxide emissions cap and trading program.
76 Fed. Reg. at 48,208. In a later rulemaking, EPA determined,
as it had for CAIR, that CSAPR is an adequate better-than-
BART alternative for participating states. Final Rule, 77 Fed.
Reg. at 33,642.

     We review EPA’s action to determine if it was “arbitrary,
capricious, an abuse of discretion, or otherwise not in
accordance with law,” or “in excess of statutory jurisdiction,
authority, or limitations, or short of statutory right.” The
standard we apply is the same under the judicial review
provision of the Clean Air Act, 42 U.S.C. § 7607(d)(9), as
under the Administrative Procedure Act, 5 U.S.C. § 706(2).
Motor Vehicle Manufacturers Ass’n v. EPA, 768 F.2d 385, 389
n.6 (D.C. Cir. 1985).

                            * * *

     We take the conservation petitioners’ arguments first. The
parties now agree that their first main challenge—that our
remand invalidating certain state emissions budges in EME
Homer City Generation, L.P. v. EPA, 795 F.3d 118 (D.C. Cir.
2015), undercut the factual basis for EPA’s finding that CSAPR
is better than BART—is moot. EPA has conducted a fresh
analysis of the better-than-BART issue in light of EME Homer
City and concluded that its changes to CSAPR in response to
the remand do not affect its determination that CSAPR is a
better-than-BART regional alternative. See 82 Fed. Reg.
45,481, 45,490–94 (Sept. 29, 2017). Although the petitioners
may challenge that finding in the future, they do not challenge
it here, and we do not consider it further.
                                6

    The petitioners argue next that EPA should not have relied
on a “generic” “presumptive BART” for modeling its
comparison to CSAPR but should have determined BART for
each individual source, using the five-factor analysis that states
must use when they make BART determinations for a source
once it has been determined to be “BART-eligible” (the term
used in this field for sources subject to BART). See UARG I,
471 F.3d at 1335–36 (quoting 40 C.F.R. § 51.308(e)(1)(ii)).

     A BART benchmark for purposes of calculating better-
than-BART is usually based on “a determination of BART for
each source subject to BART and covered by the [BART]
alternative program.” 40 C.F.R. § 51.308(e)(2)(i)(C). But
when the alternative “has been designed to meet a requirement
other than BART”—such as CSAPR’s sulfur dioxide and
nitrogen oxide emissions cap and trading program—then EPA
or a state “may determine the [BART benchmark] based on
both source-specific and category-wide information, as
appropriate.” Id. (emphasis added). EPA’s presumptive BART
is one type of category-wide information. In the rulemaking
under review here EPA stated that it had adhered to the view
that presumptive BART is “reasonable and appropriate for use
in assessing regional emissions reductions from the BART
scenario . . . since 2005,” when the category-wide information
rule was first promulgated. Final Rule, 77 Fed. Reg. 33,649–
50 (citing 71 Fed. Reg. 60,612, 60,619 (Oct. 13, 2006)).

     We think the attack on EPA’s use of presumptive BART,
authorized by 40 C.F.R. § 51.308(e)(2)(i)(C), is jurisdictionally
foreclosed by the 60-day filing window provided by the Clean
Air Act, 42 U.S.C. § 7607(b)(1). The conservation petitioners
resist that view, arguing that EPA did not invoke that
regulation, but as we have seen, it did just that in its cross-
reference to 71 Fed. Reg. at 60,619, which uses the same
language. Compare § 51.308(e)(2)(i)(C) (authorizing reliance
on category-wide information where the alternative measure
                               7

“has been designed to meet a requirement other than BART”)
with 71 Fed. Reg. at 60,919 (excepting process from normal
rule where “the alternative program is designed to meet
requirements other than BART”). See also WildEarth
Guardians v. EPA, 770 F.3d 919, 929–30 (10th Cir. 2014)
(relying on expiration of 42 U.S.C. § 7607(b)(1)’s time bar to
reject attacks on use of presumptive BART).

     In a cavalcade of attacks on alleged modelling errors, the
conservation petitioners fix on a comment that EPA failed to
address in its response to comments, specifically an assertion
that EPA’s model does not take into account the remaining
“useful life” of specific BART-eligible sources. Conservation
Petitioners’ Br. 28. As a plant nears the end of its useful life,
the state and EPA may tolerate less stringent emissions
standards in the short run (because the cost of compliance
exceeds emissions benefits in the “best” retrofit technology
scenario) in exchange for zero emissions in the long run after
the plant shuts down. See, e.g., 78 Fed. Reg. 51,686, 51,690
(Aug. 21, 2013) (shutdown of one unit in 2016 and a second in
2026 justified less stringent interim BART controls); 76 Fed.
Reg. 12,651, 12,660–61 (Mar. 8, 2011) (similar).

     EPA does not contest that it overlooked these comments.
It argues now—reasonably, in our view—that the effects of a
plant’s useful life are too speculative to model, and not
significant enough to make any modeling a useful enterprise.
We see no need to remand on this point for EPA to move this
bit of post-hoc rationalization into a rulemaking record. Each
petitioner mentioned useful life only within a few sentences of
their combined 100 pages of comments, in both instances
referring to hypothetical alternatives possibly altering the
estimates of stringency in different directions. Joint Appendix
147, 179. The Administrative Procedure Act does not
“require[] separate, specific rulings on each exception to a
decision. The pertinent regulation speaks of ‘significant’
                               8

objections. . . . The agency need only state the main reasons
for its decision and indicate that it has considered the most
important objections.” Simpson v. Young, 854 F.2d 1429, 1434
(D.C. Cir. 1988). “Indeed, the agency need not respond at all
to comments that are purely speculative. . . .” Public Citizen,
Inc. v. FAA, 988 F.2d 186, 197 (D.C. Cir. 1993) (internal
quotation marks and citation omitted).

     The rest of the conservation petitioners’ arguments fail
because they either repeat or assume premises that this Court
has already rejected in CEED and UARG I. The petitioners note
that Sierra Club was not a party to UARG I, so that issue
preclusion is not a bar to its claim. Conservation Petitioners’
Br. 37 n.2. But the precedential value of those cases still
applies. “We are of course bound by our prior panel decision,”
New York–New York, LLC v. NLRB, 676 F.3d 193, 194–95
(D.C. Cir. 2012), and “it is not only the result but also those
portions of the opinion necessary to that result by which we are
bound,” Seminole Tribe of Florida v. Florida, 517 U.S. 44, 67
(1996).

     The conservation petitioners urge us to require EPA to
apply a more stringent better-than-BART test than the one we
approved in UARG I. They say that in assessing CSAPR as an
alternative to BART, EPA should not have compared CSAPR
on its own and BART on its own (in the relevant regions), but
rather should have estimated the difference between CSAPR on
its own and CSAPR and BART together. Their reasoning is
that CSAPR is implemented under a separate provision of the
Clean Air Act unrelated to BART and will thus go into effect
regardless of BART. See 42 U.S.C. § 7410(a)(2)(D)(i)(I); 76
Fed. Reg. 48,216–17. That is, the status quo for a better-than-
BART alternative to improve must be a world that already
includes CSAPR in operation.
                               9

     This is the same argument that we rejected in UARG I,
where we held that an emissions control program in place to
satisfy an unrelated statutory provision is not disqualified from
serving as a better-than-BART alternative. We thus affirmed
EPA’s comparison between BART-without-CAIR and CAIR-
without-BART to determine the adequacy of CAIR as a BART
alternative. 471 F.3d at 1341; see also 70 Fed. Reg. at 39,139.
In so doing we applied our understanding (and EPA’s) of the
pertinent regulation, 40 C.F.R. § 51.308(e)(3). That provision
requires that, where the distribution of emissions is
significantly different (as between BART and the alternative),
the state

    must conduct dispersion modelling to determine
    differences in visibility between BART and the
    trading program for each impacted Class I area, for
    the worst and best 20 percent of days. The
    modelling would demonstrate “greater reasonable
    progress” [than BART, as required by 40 C.F.R.
    § 51.308(e) as a condition for a state’s using a
    better-than-BART alternative] if both of the
    following two criteria are met:

         (i) Visibility does not decline in any Class I
             area, and

        (ii) There is an overall improvement in
             visibility, determined by comparing the
             average differences between BART and
             the alternative over all affected Class I
             areas.

40 C.F.R. § 51.308(e)(3). This regulation was adopted in 2005.
70 Fed. Reg. at 39,104, 39,156. To the extent that the present
challenge is to the validity of the rule, it is now barred by the
Clean Air Act’s 60-day provision.
                               10

     But that bar is no obstacle to a claim that EPA’s
interpretation of its regulation fails to satisfy Auer’s
requirement of reasonableness. Auer v. Robbins, 519 U.S. 452,
461 (1997). Apart from any attack on 40 C.F.R. § 51.308(e)(3),
the conservation petitioners propose that § 51.308(e)(3) can be
read as requiring a state to show that “the [non-BART]
alternative yields greater improvements in visibility in Class I
areas,” or, formulated slightly differently, that “a BART
alternative . . . assure[s] greater visibility improvement in each
and every Class I area.” Conservation Petitioners’ Br. 37;
Conservation Petitioners’ Reply Br. 23.

     The difficulty with this reading is that it appears to render
clause (ii) pure surplusage. If clause (i) requires modelling to
show that visibility in every Class I area will be as good or
better under CSAPR than under BART, then there would be no
need to inquire whether there was an improvement measured
by “the average differences between BART and the alternative
over all affected Class I areas.” If every member of a set is
superior to every member of some alternative set, the average
of the first set is necessarily superior to the average of the
second set. Because the petitioners’ proposed interpretation of
40       C.F.R. § 51.308(e)(3) falls outside any logical
interpretation, petitioners’ argument is in our view a claim that
that regulation is invalid, and therefore beyond our jurisdiction
in light of the Clean Air Act’s 60-day limit on challenges to the
permissibility of regulations, 42 U.S.C. § 7607(b)(1).

     We should recall that the “greater reasonable progress”
that § 51.308(e) requires for any state invoking a better-than-
BART alternative is quite different from the statutorily required
mandate of “reasonable progress” for any SIP under the
regional haze statute itself, Clean Air Act § 169A(b)(2), 42
U.S.C. § 7491(b)(2). As we noted in UARG I, EPA has read
the latter requirement to encompass a showing (excusable
under limited circumstances) that complying with the BART
                                11

alternative, as well as implementing other emission controls,
will be “sufficient to attain natural visibility conditions at every
single Class I area by 2064.” UARG I, 471 F.3d at 1340 (citing
40 C.F.R. § 51.308(d)(1)(ii)). Thus, a state meeting 40 C.F.R.
§ 51.308(e)’s “greater reasonable progress” criterion does not
necessarily satisfy § 169A’s requirement of “reasonable
progress” at each Class I area. Id.

     Finally, the conservation petitioners argue that, in
comparing CSAPR and BART, EPA compared the wrong
averages. Recall that clause (ii) of EPA’s better-than-BART
standard is “determined by comparing the average differences
between BART and the alternative over all affected Class I
areas.” 40 C.F.R. § 51.308(e)(3)(ii). In this case, EPA
considered both the average visibility improvement for all
Class I areas in the modeling region subject to CSAPR, as well
as the average improvement for all Class I areas nationwide.
The conservation petitioners identify fourteen Class I areas
nationwide where BART is modeled to outperform CSAPR on
the best and worst 20 percent of days. They argue that EPA
should somehow subdivide or segment its averages, thereby
revealing that CSAPR is not better than BART in all places and
circumstances. Again, we think this dispute is foreclosed by
UARG I, where we both upheld EPA’s regulatory standard and
made clear that “nothing in [the Clean Air Act’s] ‘reasonable
progress’ language requires at least as much improvement at
each and every individual area as BART itself would achieve.”
471 F.3d at 1340 (emphasis added). It is in the nature of
averages that some particular sites may underperform while
others overperform. EPA’s rule requires aggregate average
improvement, and its comparison of the CSAPR-region Class I
areas as well as all Class I areas nationwide was reasonable.
                              12

                            * * *

     The state and industry petitioners challenge two related
aspects of EPA’s action: EPA’s rescission of its former rule
finding participation in CAIR an adequate BART alternative
and its concomitant disapproval of SIPs that relied on CAIR to
meet their obligations under BART. In essence, the petitioners
argue that if compliance with CAIR had for years allowed them
to achieve greater reasonable progress than BART would have,
their continued enforcement of emissions standards in line with
the now-defunct CAIR must necessarily be found an adequate
alternative to BART.

     But, of course, without CAIR—which all parties agree is
dead and beyond revival—there is no legal basis for a
requirement that states control their sources at CAIR levels;
indeed, for states that are not part of CSAPR, there is no legal
basis for requiring states to participate in any haze-related
interstate trading program. We cannot order EPA to consider
CAIR an alternative to BART without resurrecting CAIR itself,
a rule that we have already stricken and ordered to be vacated.
North Carolina I, 531 F.3d at 901, remanded staying vacatur
after reh’g, 550 F.3d at 1178. For this reason, EPA argues that
the state and industry petitioners’ challenge is moot; there is
apparently no relief we can give them. See Anderson v. Carter,
802 F.3d 4, 10 (D.C. Cir. 2015).

     The petitioners save themselves from mootness only by
couching their request for relief as “a contingency.” Argument
Tr. 28. They argue that “if the CSAPR-for-BART rule—which
NPCA and Sierra Club are challenging here—were to be
vacated or rescinded, approval of the CAIR-for-BART SIPs
would protect State and Industry Petitioners from the adverse
effects of EPA’s June 2012 actions.” State & Industry
Petitioners’ Reply Br. 3. The petitioners seem to have in mind
                                  13

CSAPR’s litigation history. When CSAPR was first challenged
in this Court, we stayed implementation pending a decision on
the merits and ordered EPA to continue to implement CAIR.
EME Homer City Generation, L.P. v. EPA, No. 11-1302, Order
(D.C. Cir. Dec. 30, 2011). After argument on the merits, we
vacated CSAPR and again ordered EPA to keep implementing
CAIR. EME Homer City Generation, L.P. v. EPA, 696 F.3d 7,
37–38 (D.C. Cir. 2012).

     But the logic of that analogy does not follow here. In North
Carolina II we recognized that CAIR offered some
environmental benefit, so that EPA’s flawed CAIR rule was
better than nothing. 550 F.3d at 1178. For that same reason we
left CAIR in place while remanding CSAPR in EME Homer
City. See 696 F.3d at 37–38. But here, CSAPR itself is not
challenged, only EPA’s finding that CSAPR is a better-than-
BART alternative. Even if we were to grant the conservation
petitioners’ request, vacating CSAPR-for-BART would not
restore CAIR-for-BART; it would leave BART in place alone,
and CAIR-based SIPs would not become any less problematic.
At any rate, because we do not grant the conservation
petitioners’ request, and the state and industry petitioners have
hitched their wagon to that star, their contingency theory fails.

    The petitioners finally argue that EPA could nevertheless
approve their CAIR-based SIPs, despite CAIR’s demise; EPA
has in fact done so in one instance, so it must be feasible.
Indeed, EPA approved Connecticut’s SIP application on April
26, 2013, 79 Fed. Reg. 39,322, 39,328 (July 10, 2014),1 even
1
 Although EPA signed off on Connecticut’s SIP on April 26, 2013,
publication in the Federal Register did not follow until July 10, 2014.
See 79 Fed. Reg. at 39,329. But the Federal Register notice includes
an “editor’s note” stating that it did not receive the document until
July 3, 2014. See id. At oral argument EPA explained the lapse as
                               14

after it had disapproved the petitioners’ CAIR-reliant SIPs. Of
course it is true that “inconsistent treatment is the hallmark of
arbitrary agency action.” Catawba County v. EPA, 571 F.3d
20, 51 (D.C. Cir. 2009). But in this case the rapidly changing
legal context explains the superficially inconsistent decisions.

     EPA disapproved the state petitioners’ SIPs on June 7,
2012 in the final action that is challenged here. Final Rule, 77
Fed. Reg. at 33,653. At that time, North Carolina I’s reversal
of CAIR had been on the books nearly four years, and North
Carolina II had made abundantly clear that CAIR was suffered
to continue only until EPA promulgated a revised cap and
trading rule, at which time CAIR would be vacated. See 550
F.3d at 1178. EPA promulgated its final CSAPR rule on
August 8, 2011. 76 Fed. Reg. at 48,208. By June 2012, we had
stayed implementation of CSAPR while we reviewed the rule
on its merits. But, apparently expecting that CSAPR would
shortly be affirmed and take effect, EPA disapproved pending
CAIR-based SIP applications and instructed states to submit
SIPs based either on CSAPR or other non-CAIR alternatives to
BART. See Final Rule, 77 Fed. Reg. 33,647–48. EPA may
have been over-optimistic in its sense of timing, but its
expectation that CSAPR would be approved and take effect was
not unreasonable, and indeed was largely justified by the
Supreme Court’s affirmance of CSAPR, EPA v. EME Homer
City Generation, L.P., 134 S. Ct. 1584 (2014), subject to “as-
applied” challenges to EPA’s state emissions budgets alleged
to constitute “over-control,” id. at 1608–10; see also EME
Homer City, 795 F.3d at 118 (granting some of petitioners’ as-
applied challenges).


the result of “a long dispute between the Agency and the Office of
the Federal Register over something,” presumably something
unrelated to the SIP at issue. Argument Tr. 32.
                              15

     But that Supreme Court ruling did not come until 2014. In
the interim, in August 2012, we ordered EPA to continue
implementing CAIR, see EME Homer City, 696 F.3d at 38, and
on November 19, 2012, EPA issued a memo announcing that it
would approve CAIR-based SIPs pending a final resolution of
the CSAPR challenge. Memorandum from Gina McCarthy,
Assistant Administrator, EPA, to Air Division Directors,
Regions 1–10, Nov. 19, 2012, at 1–3. Connecticut’s partially
CAIR-based SIP was submitted in August 2012 and approved
by EPA the following April. See 79 Fed. Reg. at 39,329. In
sum, the difference in timing comes down to this: In June of
2012, EPA could have approved CAIR-based SIPs such as
petitioners’ but chose not to, given its not unreasonable
expectation that CAIR was shortly approaching its end; in April
of 2013 (and for the indefinite future while CSAPR’s litigation
fate remained uncertain), our direction in EME Homer City
effectively barred EPA from rejecting Connecticut’s CAIR-
based SIP on the ground of CAIR’s well-known legal infirmity.
EPA suggests a variety of other factors that made its approval
of Connecticut’s SIP reasonable, including Connecticut’s
comparatively low emissions and its only partial reliance on
CAIR. We need not address those factors, however. EPA’s
different treatments of the petitioning states and Connecticut
were not unreasonable at the relevant times, and the difference
certainly provides no basis for us to declare the petitioning
states subject to a rule that no longer exists.

                            * * *

     Because we find no merit in the conservation petitioners’
arguments and can afford no relief to the state and industry
petitioners, the petitions are

                                                       Denied.
