2. Comments that the EPA must make specific factual findings to
meet the

requirements of section 110(a)(2)(H)(ii) to have authority to issue a
SIP call.
    Comment: A number of commenters argued that even if section
110(k)(5) does not require the EPA to provide a technical analysis to
support a finding of substantial inadequacy, section 110(a)(2)(H)(ii)
does impose this obligation. The commenters noted that section
110(a)(2)(H)(ii) requires states to revise their SIPs ``whenever the
Administrator finds on the basis of information available to the
Administrator that the plan is substantially inadequate.'' The
commenters claimed that this statutory language imposes a requirement
for the EPA to ``find'' the SIP inadequate and ``clearly indicates that
a SIP Call must be justified by factual findings supported by record
evidence.''
    One commenter argued that the use of the word ``finds'' should be
read in light of the dictionary definition of ``find''--``to discover
by study or experiment.'' The commenter noted that courts commonly hold
that agencies must draw a link between the facts and a challenged
agency decision. To support this basic principle of administrative law,
the commenter cited a litany of cases including: Motor Vehicle Mfrs
Ass'n v. State Farm Mut. Auto Ins. Co., 463 U.S. 29, 43 (1983);
Appalachian Power Co. v. EPA, 251 F.3d 1026, 1034 (D.C. Cir. 2001); Tex
Tin Corp. v. EPA, 992 F.2d 353, 356 (D.C. Cir. 1993); Nat'l Gypsum v.
EPA, 968 F.2d 40, 43-44 (D.C. Cir. 1992); Michigan v. EPA, 213 F.3d
663, 681 (D.C. Cir. 2000). Thus, the commenter suggested that the
statutory language of section 110(a)(2)(H)(ii) requires a specific
factual or technical demonstration concerning the ambient air impacts
of an inadequate SIP provision, even if the language of section
110(k)(5) does not.
    Another commenter argued that the phrase ``on the basis of
information available to the Administrator'' in section
110(a)(2)(H)(ii) means that the EPA must not only consider the specific
terms of the SIP provisions relative to the legal requirements of the
statute but must also consider other information that is ``available,''
including how the provisions have been affecting air quality or
enforcement since approval. In support of this proposition, the
commenter cited 1970 legislative history for section 110(a)(2)(H):

    Whenever the Secretary or his representative finds from new
information developed after the plan is approved that the plan is
not or will not be adequate to achieve promulgated ambient air
quality standards he must notify the appropriate States and give
them an opportunity to respond to the new information.\320\
---------------------------------------------------------------------------

    \320\ See S. Rep No. 91-1196 at 55-56 (1970).

    Thus, the commenter concluded that the EPA must not only find that
the SIP is facially inconsistent with the legal requirements of the CAA
but also find it ``substantially inadequate'' to achieve the goals of
the requirements as a factual matter before issuing a SIP call. The
implication of the commenter's argument is that section
110(a)(2)(H)(ii) imposes additional limitations upon the EPA's
authority to issue a SIP call.
    Response: The EPA disagrees that it has not made the findings
necessary to support the present SIP call action. The thrust of the
commenters' argument is that the facts that the EPA ``finds'' or the
``information'' upon which the EPA bases such a finding can only be
technical or scientific facts proving that a given SIP provision
resulted in emissions that caused a specific violation of the NAAQS. As
with section 110(k)(5), however, nothing in section 110(a)(2)(H)(ii)
compels such a narrow reading. The plain language of section
110(a)(2)(H)(ii) does not support the commenters' arguments. To the
extent that section 110(a)(2)(H)(ii) is ambiguous, however, the EPA
does not interpret it to require the types of technical findings
claimed by the commenters in the case of SIP provisions that do not
meet legal requirements of the CAA. To the contrary, the EPA interprets
the statutory language to leave to the Agency's discretion what facts
or information are necessary to find that a given SIP provision is
substantially inadequate. In short, the EPA's ``finding'' may be a
finding that a SIP provision does not meet applicable legal
requirements without definitive proof that this legal deficiency caused
a specific outcome, such as a specific impact on the NAAQS or a
specific enforcement action.
    First, section 110(a)(2)(H)(ii) does not on its face directly
address the scope of the EPA's authority, unlike section 110(k)(5).
Section 110(a)(2)(H)(ii) appears in section 110(a)(2), which contains a
listing of specific structural or program requirements that each
state's SIP must include. In the case of section 110(a)(2)(H)(ii), the
CAA requires each state to have provisions in its SIP that ``provide
for revision of such plan'' in the event that the EPA issues a SIP
call. Given that section 110(k)(5) is the provision that directly
addresses the EPA's authority to issue a SIP call, section
110(a)(2)(H)(ii) should not be interpreted in a way that contradicts or
curtails the broad authority provided in section 110(k)(5). The EPA
does not interpret section 110(k)(5) to require proof that a given SIP
provision caused a specific environmental harm or undermined a specific
enforcement action in order to find the provision substantially
inadequate. If the provision fails to meet fundamental legal
requirements of the CAA for SIP provisions, that alone is sufficient.
    Second, even if read in isolation, section 110(a)(2)(H)(ii) does
not specify what type of finding the EPA is required to make or specify
the way in which the Agency should make such a finding. The EPA agrees
that this section of the CAA describes findings that the EPA makes ``on
the basis of information available to the Administrator that the plan
is substantially inadequate to attain'' the NAAQS. This section does
not, however, expressly state that the ``information'' in question must
be a particular form of information, nor does it expressly require any
specified form of technical analysis such as modeling that demonstrates
that a particular SIP deficiency caused a violation of the NAAQS.
Because the term ``information'' is not limited in this way, the EPA
interprets it to mean whatever form of information is relevant to the
finding in question. For certain types of deficiencies, the EPA may
determine that such a technical analysis is appropriate, but that does
not mean that it is required as a basis for all findings of substantial
inadequacy.\321\
---------------------------------------------------------------------------

    \321\ See, e.g., ``Finding of Significant Contribution and
Rulemaking for Certain States in the Ozone Transport Assessment
Group Region for Purposes of Reducing Regional Transport of Ozone;
Final rule,'' 63 FR 57355 (October 27, 1998) (EPA found that the
SIPs of multiple states did not adequately control emissions that
resulted in significant contribution to nonattainment in other
states); ``Action To Ensure Authority To Issue Permits Under the
Prevention of Significant Deterioration Program to Sources of
Greenhouse Gas Emissions: Finding of Substantial Inadequacy and SIP
Call; Final rule,'' 75 FR 77697 (December 13, 2010) (EPA found that
the SIPs of multiple states did not meet the legal requirements for
PSD permitting for GHG emissions).
---------------------------------------------------------------------------

    Third, section 110(a)(2)(H)(ii), like section 110(k)(5), is not
limited to findings related exclusively to attainment of the NAAQS.
Section 110(a)(2)(H)(ii) also expressly refers to findings by the EPA
that a SIP is substantially inadequate ``to otherwise comply with any
additional requirements established under'' the CAA. The EPA interprets
this explicit reference to ``any additional requirements'' to include
any legal requirements applicable to SIP provisions, such as the
requirement that emission limitations must apply continuously. The
commenters misconstrue section 110(a)(2)(H)(ii) to

refer exclusively to provisions that are literally found to cause a
specific violation of the NAAQS. The EPA acknowledges that the
legislative history quoted by the commenters discusses findings related
to a failure of a SIP to attain the NAAQS, but the passage quoted does
not explain the meaning of ``new information'' any more specifically
than the statute, nor does the passage explain why the actual statutory
text of section 110(a)(2)(H)(ii) now refers to findings related to
failures to meet ``any additional requirements'' of the CAA.\322\
Moreover, the commenters did not address the changes to the CAA in 1977
that added to the statutory language to refer to other requirements,
nor did they address the changes to the CAA in 1990 that added section
110(k)(5), which refers to all other requirements of the CAA. The EPA
believes that the more recent changes to the statute in fact support
its view that section 110(a)(2)(H)(ii) entails compliance with the
legal requirements of the CAA, not the narrow reading advocated by the
commenters.
---------------------------------------------------------------------------

    \322\ The EPA notes that the significance of this 1970
legislative history was raised in US Magnesium, LLC v. EPA, 690 F.3d
1157, 1166 (10th Cir. 2012). That court found the legislative
history ``inapposite'' simply because it did not pertain to section
110(k)(5) which Congress added to the CAA in 1990. This legislative
history passage is of limited significance in this action as well.
---------------------------------------------------------------------------

    Fourth, the EPA disagrees with the commenters' arguments that it
did not make factual ``findings'' to support this SIP call. To the
contrary, the EPA has made numerous factual determinations with regard
to the specific SIP provisions at issue. For example, for those SIP
provisions that include automatic exemptions for emissions during SSM
events, the EPA has found that the provisions are inconsistent with the
definition of ``emission limitation'' in section 302(k) and that SIP
provisions that allow sources to exceed otherwise applicable emission
limitations during SSM events may interfere with attainment and
maintenance of the NAAQS. The EPA has also made the factual
determination that other SIP provisions that authorize director's
discretion exemptions during SSM events are inconsistent with the
statutory provisions applicable to the approval and revision of SIP
provisions. The EPA has found that overbroad enforcement discretion
provisions are inconsistent with the enforcement structure of the CAA
in that they could be interpreted to allow the state to make the final
decision whether such emissions are violations, thus impeding the
ability of the EPA and citizens to enforce the emission limitations of
the SIP. Similarly, the EPA has found, consistent with the court's
decision in NRDC v. EPA, that affirmative defenses in SIP provisions
are inconsistent with CAA requirements because they operate to alter or
eliminate the jurisdiction of the courts to determine liability and
impose penalties. In short, the EPA has made the factual findings that
specific provisions are substantially inadequate to meet requirements
of the CAA, as contemplated in both section 110(a)(2)(H)(ii) and
section 110(k)(5).
    Finally, the EPA notes that the cases cited by the commenters to
support their contentions concerning the factual basis for agency
decisions are not relevant to the specific question at hand. The
correct question is whether section 110(a)(2)(H)(ii) requires the type
of factual or technical analysis that they claim. None of the cases
they cited address this specific issue. By contrast, the decision of
the Tenth Circuit in US Magnesium, LLC v. EPA is much more relevant. In
that decision, the court concluded that the EPA's authority under
section 110(k)(5) is not restricted to situations where a deficient SIP
provision caused a specific violation of the NAAQS and the exercise of
that authority does not require specific factual findings that the
provision caused such impacts.\323\
---------------------------------------------------------------------------

    \323\ Id., 690 F.3d 1157, 1166.
---------------------------------------------------------------------------

    3. Comments that the EPA lacks authority to issue a SIP call
because it is interpreting the term ``substantial inadequacy''
incorrectly.
    Comment: Some commenters claimed that although the term
``substantially inadequate'' is not defined in the statute, the EPA
made no effort to interpret the term. Citing Qwest Corp. v. FCC, 258
F.3d 1191, 1201-02 (10th Cir. 2001), the commenters argued that the EPA
is not entitled to any deference to its interpretation of the term
``substantial inadequacy.''
    Other commenters acknowledged that the EPA took the position that
the term ``substantially inadequate'' is not defined in the CAA and
that the Agency can establish an interpretation of that provision under
Chevron step 2. However, these commenters disagreed that the EPA's
interpretation of the term in the February 2013 proposal was
reasonable. In particular, the commenters disagreed with the EPA's view
that once a SIP provision is found to be ``facially inconsistent'' with
a specific legal requirement of the CAA, nothing more is required to
find the provision ``substantially inadequate'' to ``comply with'' that
requirement. Commenters claimed that the EPA's interpretation conflicts
with the statute because it ignores the statutory requirement that a
SIP call be based on inadequacies that are ``substantial'' and that the
interpretation does not meet the ``high bar'' Congress established
before states could be required to undertake the difficult task of
revising a SIP.
    State commenters claimed that the requirement that the EPA must
determine that the SIP is ``substantially'' inadequate establishes a
heavy burden for the EPA. The commenters relied on a dictionary
definition of ``substantially'' as meaning ``considerable in
importance, value, degree, amount, or extent.'' The commenters argued
that when modifying the word ``inadequate,'' the use of the modifier
``substantially'' in section 110(k)(5) enhances the degree of proof
required. Thus, the commenters argued that the EPA cannot just assume
that the provisions may prevent attainment of the NAAQS.
    Other industry commenters disagreed that the term ``substantially
inadequate'' is ambiguous but claimed that even if it were, the EPA's
own interpretation is vague and ambiguous. The commenters asserted that
the EPA's statement that it must evaluate the adequacy of specific SIP
provision ``in light of the specific purposes for which the SIP
provision at issue is required'' and with respect to whether the
provision meets ``fundamental legal requirements applicable to such a
provision'' is not a reasonable interpretation of the statutory
language. Furthermore, the commenters argued, the EPA's interpretation
of section 110(k)(5) to authorize a SIP call in the absence of any
causal evidence that the SIP provision at issue causes a particular
environmental impact reads out of the statute ``the explicit
requirement that a SIP call related to NAAQS be made only where the
state plan is substantially inadequate to attain or maintain the
relevant standard.''
    Response: The EPA disagrees with commenters who claimed that the
Agency did not explain its interpretation of section 110(k)(5) in
general, or the term ``substantially inadequate'' in particular, in the
February 2013 proposal. To the contrary, the EPA provided an
explanation of why it considers section 110(k)(5) to be ambiguous and
provided a detailed explanation of how the Agency is interpreting and
applying that statutory language to the specific SIP provisions at
issue in this action.\324\ Moreover, the EPA explained why it believes
that the four major types of

provisions at issue are inconsistent with applicable legal requirements
of the CAA and thus substantially inadequate. In the SNPR, the EPA
reiterated its interpretation of section 110(k)(5) with respect to
affirmative defense provisions in SIPs but updated that interpretation
in response to the logic of the more recent court decision in NRDC v.
EPA. Thus, the commenters' reliance on the Qwest decision is not
appropriate, because the EPA did explain its interpretation of the
statute and it is not one that is contrary to the statute. A more
appropriate precedent is the decision in US Magnesium, LLC v. EPA, in
which the same court upheld the EPA's interpretation of its authority
under section 110(k)(5). In short, the EPA believes that section
110(k)(5) provides the EPA with discretion to determine what
constitutes a substantial inadequacy and to determine the appropriate
basis for such a finding in light of the relevant CAA requirements at
issue. Thus, the commenters are in error that the EPA did not
articulate its interpretation of section 110(k)(5).
---------------------------------------------------------------------------

    \324\ See February 2013 proposal, 78 FR 12459 at 12483-88.
---------------------------------------------------------------------------

    The EPA also disagrees with those commenters who argued that the
Agency has ignored or misinterpreted the term ``substantial'' in this
action. As many commenters acknowledged, this term is not defined in
the statute. Their reliance on a dictionary definition, however, is
based on the incorrect premise that a failure to comply with the legal
requirements of the CAA for SIP provisions is not ``considerable in
importance, value, degree, amount, or extent.''
    First, the commenters' argument ignores the full statutory language
of section 110(k)(5) in which the EPA is authorized to issue a SIP call
whenever it determines that a given SIP provision is inadequate, not
only because of impacts on attainment of the NAAQS but also upon a
failure to meet ``any other requirement'' of the CAA. As explained in
the February 2013 proposal and in the SNPR, the EPA interprets its
authority under section 110(k)(5) to encompass any type of deficiency,
including failure to meet specific legal requirements of the CAA for
SIP provisions. Failure to comply with these legal requirements can
have the effect of interfering with attainment and maintenance of the
NAAQS (e.g., by allowing unlimited emissions from sources during SSM
events), but the failure to comply with the legal requirements is in
and of itself a basis for a SIP call.
    Second, the commenters' argument implies that failure of a SIP
provision to meet a legal requirement of the CAA is not a
``substantial'' inadequacy. The EPA strongly disagrees with the view
that complying with applicable legal requirements is not an important
consideration in general, and not important with respect to the
specific legal defects at issue here. For example, the EPA considers a
SIP provision that does not apply continuously because it contains SSM
exemptions to be substantially inadequate because it fails to meet
legal requirements of sections 110(a)(2)(A), 110(a)(2)(C) and 302(k).
In particular, failure to meet the legal requirements for an emission
limitation as contemplated in section 302(k) is a ``substantial''
inadequacy. The EPA is not alone in this view; the D.C. Circuit in the
Sierra Club v. Johnson case held that emission limitations must be
continuous and cannot contain SSM exemptions. If inclusion of SSM
exemptions in emission limitations were not a ``substantial''
deficiency from the court's perspective, presumably the court would
have ruled differently. As another example, the EPA considers the
inclusion of affirmative defenses in SIP provisions that operate to
alter the jurisdiction of the courts to be a substantial inadequacy.
Again, the EPA's view that SIP provisions cannot interfere with the
enforcement structure of the CAA set forth in section 113 and section
304 is not unreasonable. The court's decision in NRDC v. EPA held that
EPA regulations cannot alter or eliminate the jurisdiction of courts to
determine liability and impose remedies in judicial enforcement cases
and this same logic extends to the states in SIP provisions. Contrary
to the arguments of the commenters, the EPA reasonably interprets the
term ``substantial'' in section 110(k)(5) to include compliance with
the legal requirements of the CAA applicable to SIP provisions.
    Third, the EPA notes that its reading of section 110(k)(5) does not
``read out of the statute'' the statutory language that SIP provisions
can be substantially inadequate ``to attain or maintain the relevant
NAAQS'' as claimed by the commenters. The EPA agrees that SIP
provisions can be found substantially inadequate for this specific
reason, but it is the commenters who read words out of section
110(k)(5) by disregarding the portion of the statute that also
authorizes a SIP call whenever a SIP provision does not ``comply with
any requirement of'' the CAA. Indeed, the EPA believes that SIP
provisions that fail to meet the specific legal requirements of the CAA
are very likely to have these impacts as well; e.g., the unlimited
emissions authorized by SSM exemptions can interfere with attainment
and maintenance of the NAAQS. The EPA believes that Congress
consciously included these fundamental legal requirements in order to
assure that SIP provisions will achieve the objectives of the CAA, such
as attainment and maintenance of the NAAQS. For example, legislative
history for section 302(k) indicates that Congress intentionally
required that emission limitations apply continuously in order to
assure that they would achieve these goals as well as be consistent
with the enforcement structure of the CAA.\325\
---------------------------------------------------------------------------

    \325\ See, e.g., H.R. 95-294, at 92 (1977) (referring to
emission limitations as a fundamental tool for assuring attainment
and maintenance of the NAAQS and stating that unless they are
``complied with at all times, there can be no assurance that ambient
standards will be attainment and maintained.''
---------------------------------------------------------------------------

    4. Comments that the EPA lacks authority to issue a SIP call
because it is required to ``quantify'' the magnitude of any alleged SIP
deficiency in order to establish that it is substantial.
    Comment: A number of commenters argued that, in addition to failing
to provide a required technical analysis to support a SIP call, the EPA
was also failing to quantify in advance the degree of inadequacy that
is necessary for a given SIP provision to be substantially inadequate.
The commenters asserted that the EPA has a burden to define in advance
what amount of inadequacy is ``substantial,'' before the Agency can
require states to comply with a SIP call. Some commenters made this
argument based upon their experience with prior SIP call rulemakings,
such as the NOX SIP call in which the Agency performed such
an analysis. Other commenters, however, evidently based this argument
upon their reading of the D.C. Circuit's decision in EME Homer City
Generation, L.P. v. EPA.\326\ Some commenters also argued that ``all''
past EPA SIP calls have been based upon a specific technical analysis
concerning the sufficiency of a SIP to provide for attainment and
maintenance of a NAAQS and that this establishes that such an analysis
is always required.
---------------------------------------------------------------------------

    \326\ 696 F.3d 7, 29 (D.C. Cir. 2012) rev'd, 134 S. Ct. 1584
(2014).
---------------------------------------------------------------------------

    Response: The EPA disagrees that section 110(k)(5) requires the
Agency to ``quantify'' the degree of inadequacy in a given SIP
provision before issuing a SIP call. As explained in detail in the
February 2013 proposal and this document, the EPA interprets section
110(k)(5) to authorize the Agency to determine the nature of the
analysis necessary to make a finding that a SIP provision is
substantially inadequate. The EPA agrees that for certain SIP call
actions, such as the NOX SIP call, the

specific nature of the SIP call in question for section 110(a)(2)(D)(i)
did warrant a technical evaluation of whether the emissions from
sources in particular states were significantly contributing to
violations of a NAAQS in other states. Thus, the EPA elected to perform
a specific form of analysis to determine whether emissions from sources
in certain states significantly contributed to violations of the NAAQS
in other states, and if so, what degree of reductions were necessary to
remedy that interstate transport.
    The nature of the SIP deficiencies at issue in this action does not
require that type of technical analysis and does not require a
``quantification'' of the extent of the deficiency. In this action, the
EPA is promulgating a SIP call action that directs the affected states
to revise existing SIP provisions with specific legal deficiencies that
make the provisions inconsistent with fundamental legal requirements of
the CAA for SIPs, e.g., automatic exemptions for emissions during SSM
events or affirmative defense provisions that limit or eliminate the
jurisdiction of courts to determine liability and impose remedies for
violations. Accordingly, the EPA has determined that it is not
necessary to establish that these deficiencies literally caused a
specific violation of the NAAQS on a particular day or undermined a
specific enforcement case. It is sufficient that the provisions fail to
meet a legal requirement of the CAA and thus are substantially
inadequate as provided in section 110(k)(5).
    5. Comments that the EPA's interpretation of substantial inadequacy
would override state discretion in development of SIP provisions.
    Comment: Some state and industry commenters argued that the EPA's
interpretation of its authority under section 110(k)(5) is wrong
because it is inconsistent with the principle of cooperative
federalism. These commenters asserted that the EPA's interpretation of
the term ``substantially inadequate,'' as explained in the February
2013 proposal, would allow the Agency to dictate that states revise
their SIPs without any consideration of whether the states' preferred
control measures affect attainment of the NAAQS, thereby expanding the
EPA's role in CAA implementation. Consequently, these commenters
concluded, the EPA's interpretation of section 110(k)(5) is neither
``reasonable'' nor ``a permissible construction of the statute'' under
the principles of Chevron deference.\327\
---------------------------------------------------------------------------

    \327\ Chevron, U.S.A., Inc. v. Natural Res. Def. Council, Inc.,
467 U.S. 837, 843-44 (1984).
---------------------------------------------------------------------------

    Response: The EPA disagrees with the commenters' view of the
cooperative-federalism relationship established in the CAA, as
explained in detail in section V.D.2 of this document. Because the
commenters are misconstruing the respective responsibility and
authorities of the states and the EPA under cooperative federalism, the
Agency does not agree that its interpretation of section 110(k)(5) is
``unreasonable'' for this reason under the principles of Chevron. As
explained in detail in the February 2013 proposal, the EPA interprets
its authority under section 110(k)(5) to include the ability to require
states to revise their SIP provisions to correct the types of
deficiencies at issue in this action.
    Section 110(k)(5) explicitly authorizes the EPA to issue a SIP call
for a broad range of reasons, including to address any SIP provisions
that relate to attainment and maintenance of the NAAQS, to interstate
transport, or to any other requirement of the CAA.\328\ The EPA's
authority and responsibility to review SIP submissions in the first
instance is to assure that they meet all applicable procedural and
substantive requirements of the CAA, in accordance with the
requirements of sections 110(k)(3), 110(l) and 193. The EPA's authority
and responsibility under the CAA includes assuring that SIP provisions
comply with specific statutory requirements, such as the requirement
that emission limitations apply to sources continuously. The CAA
imposes these statutory requirements in order to assure that the larger
objectives of SIPs are achieved, such as the attainment and maintenance
of the NAAQS, protection of PSD increments, improvement of visibility
and providing for effective enforcement. The CAA imposes this authority
and responsibility upon the EPA when it first evaluates a SIP
submission for approval. Likewise, after the initial approval, section
110(k)(5) authorizes the EPA to require states to revise their SIPs
whenever the Agency later determines that to be necessary to meet CAA
requirements. This does not in any way allow the EPA to interfere in
the states' selection of the control measures they elect to impose to
satisfy CAA requirements relating to NAAQS attainment and maintenance,
provided that those selected measures comply with all CAA requirements
such as the need for continuous emissions limitations. Accordingly, the
EPA believes that its interpretation of section 110(k)(5) is fully
consistent with the letter and the purpose of the principles of
cooperative federalism.
---------------------------------------------------------------------------

    \328\ See, e.g., US Magnesium, LLC v. EPA, 690 F.3d 1157, 1168
(10th Cir. 2012) (citing 42 U.S.C. 7410(k)(5)) (holding that the EPA
may issue a SIP call not only based on NAAQS violations, but also
whenever ``EPA determines that a SIP is no longer consistent with
the EPA's understanding of the CAA''); id. at 1170 (upholding the
EPA's authority ``to call a SIP in order to clarify language in the
SIP that could be read to violate the CAA,'' even absent a pertinent
judicial finding).
---------------------------------------------------------------------------

    6. Comments that the EPA cannot issue a SIP call for an existing
SIP provision unless the provision was deficient at the time the state
originally developed and submitted the provision for EPA approval.
    Comment: Commenters argued that the EPA is using the SIP call to
require states to change SIP provisions that were acceptable at the
time they were originally approved and argued that section 110(k)(5)
cannot be used for that purpose. Specifically, one commenter asserted
that section 110(k)(5) provides that findings of substantial inadequacy
shall ``subject the State to the requirements of this chapter to which
the State was subject when it developed and submitted the plan for
which such finding was made.'' (Emphasis added by commenter.) The
implication of the commenters' argument is that a SIP provision only
needs to meet the requirements of the CAA that were applicable at the
time the state originally developed and submitted the provision for EPA
approval. Because the EPA has no authority to issue a SIP call under
their preferred reading of section 110(k)(5), the commenters claimed,
the EPA would have to use its authority under section 110(k)(6) and
would have to establish that the original approval of each of the
provisions at issue in this action was in error.
    Response: The EPA disagrees with this reading of section 110(k)(5).
As an initial matter, the commenter takes the quoted excerpt of the
statute out of context. The quoted language follows ``to the extent the
Administrator deems appropriate.'' Thus, it is clear when the statutory
provision is read in full that the EPA has discretion in specifying the
requirements to which the state is subject and is not limited to
specifying only those requirements that applied at the time the SIP was
originally ``developed and submitted.'' Moreover, this cramped reading
of section 110(k)(5) is not a reasonable interpretation of the statute
because by this logic, the EPA could never require states to update
grossly out-of-date SIP provisions so long as the provisions originally
met CAA requirements. Given that the CAA creates a process by which

the EPA is required to establish and to update the NAAQS on a
continuing basis, and states are required to update and revise their
SIPs on a continuing basis, the Agency believes that Congress would not
have intended that SIP provisions remain static for all time simply
because they were adequate when first developed and approved. Such an
interpretation would mean that subsequent legally significant events
such as amendments of the CAA, court decisions interpreting the CAA and
new or revised EPA regulations are not relevant to the continuing
adequacy of existing SIP provisions. Similarly, such an interpretation
would mean that facts arising later could never provide a basis for a
SIP call, e.g., to address interstate transport that was not evident at
the time of the original development and approval of the SIP provisions
or that needs to be addressed further because of a revised NAAQS.
    The commenters also argued that if a state's SIP provision was
flawed at the time the EPA approved it, then the Agency's only
alternative for addressing the deficient provision is through the error
correction authority of section 110(k)(6). The EPA disagrees. The CAA
provides a number of tools to address flawed SIPs and the EPA does not
interpret these provisions to be mutually exclusive. While the EPA
could potentially have relied on section 110(k)(6) to remove the
deficient provisions at issue in this action, the Agency believes that
section 110(k)(5) authority also provides a means to address flawed SIP
provisions. As explained in the February 2013 proposal, the EPA
specifically considered the relative merits of reliance on section
110(k)(5) and section 110(k)(6) and determined that the former was a
better approach for this action.\329\ In the present circumstances, the
EPA is not addressing a single targeted flaw, i.e., a specific SIP
revision that was flawed. Moreover, the EPA is not only dealing with a
multitude of states in this action, but also in many cases with
numerous SIP provisions developed over the years by a specific state.
The provisions at issue often are included in several different places
in a complex SIP and can affect multiple emission limitations in the
SIP that apply to sources for purposes of multiple NAAQS.
---------------------------------------------------------------------------

    \329\ See February 2013 proposal, 78 FR 12459 at 12483, n.72.
---------------------------------------------------------------------------

    Comparing the SIP call and error correction approaches, the EPA
concluded that the SIP call authority under section 110(k)(5) provides
the better approach for this action, in that it allows the states to
evaluate the overall structure of their existing SIPs and determine how
best to modify the affected SIP provisions in order to address the
identified deficiencies. By contrast, use of the error correction
authority under section 110(k)(6) would result in immediate disapproval
and removal of existing SIP provisions from the SIP, which could cause
confusion in terms of what requirements apply to sources. Moreover, the
EPA's disapproval of a SIP submission through an error correction that
reverses a prior SIP approval of a required SIP provision starts a
``sanctions clock,'' and sanctions would apply if the state has not
submitted a revised SIP within 18 months. Similarly, the EPA would be
required to promulgate a FIP if the Agency has not approved a revised
SIP submission from the state within 24 months. In comparison, the
sanctions and federal plan ``clocks'' would not start under the SIP
call approach unless and until the state fails to submit a SIP revision
in response to this SIP call, or unless and until the EPA disapproves
that SIP submission. As explained in the February 2013 proposal, the
EPA determined that the SIP call process was a better procedure through
which to address the deficient SIP provisions at issue in this action.
    7. Comments that the EPA failed to consider how excess emissions
resulting from SSM exemptions would affect compliance with specific
NAAQS, including NAAQS with different averaging periods or different
statistical forms.
    Comment: In addition to general claims that the EPA failed to
provide required technical analysis to support the proposed SIP call to
states for automatic and discretionary SSM exemptions, commenters
specifically argued that the EPA is required to establish that these
exemptions have caused violations in light of the considerations such
as the averaging time or statistical form of specific NAAQS. The
implication of the commenters' argument is that in order to demonstrate
that a given SIP provision with an SSM exemption is substantially
inadequate under section 110(k)(5), the EPA has to establish
definitively that the emissions during SSM events would cause a
violation of a particular NAAQS. This would potentially include an
evaluation of the impacts of the exempted emissions on NAAQS with
different averaging periods, e.g., impacts on an annual NAAQS, a 24-
hour NAAQS, or a 1-hour NAAQS, and impacts on NAAQS with different
statistical forms, e.g., a NAAQS that measures attainment by an annual
arithmetical mean versus one that is measured by a 98th-percentile
value. Moreover, commenters alluded to the difficulty of ascertaining
definitively how emissions of specific precursor pollutants during a
given exempted SSM event would affect attainment of one or more NAAQS.
    To support the argument that the validity of SSM exemptions must be
evaluated with respect to specific NAAQS, the commenters relied upon
recent modeling guidance for the 1-hour NO2 NAAQS in which,
the commenters claimed, the EPA directed states to disregard emissions
during SSM events for purposes of demonstrating compliance with that
NAAQS. The commenters claimed that the cited EPA guidance supports
their argument that emissions from a source during any specific SSM
event are unlikely to cause a violation of the 1-hour NO2
NAAQS. Accordingly, the commenters argued that the EPA has no authority
to interpret the CAA to preclude exemptions for emissions during SSM
events without first demonstrating that the exempt emissions cause
NAAQS violations.
    Response: As explained in the February 2013 proposal, and in
response to other comments in this action, the EPA does not interpret
section 110(k)(5) to require a specific technical analysis to support a
SIP call related to legal deficiencies in SIP provisions. In section
110(k)(5), Congress left it to the Agency's discretion to determine
what type and level of analysis is necessary to establish that a SIP
provision is substantially inadequate. As explained in the February
2013 proposal, the EPA does not need to define the precise contours of
its authority under section 110(k)(5) for all potential types of SIP
deficiencies in this action. For purposes of this action, it is
sufficient that the SIP provisions at issue are inconsistent with
applicable requirements. While an ambient air quality impact analysis
may be appropriate to support a SIP call with respect to certain
requirements of the CAA, e.g., a SIP call for failure to have SIP
provisions to prevent significant contribution to nonattainment in
another state in accordance with section 110(a)(2)(D)(i)(I), the EPA
does not interpret the CAA to require such an analysis in all
instances. In particular, where the substantial inadequacy is related
to a failure to meet a fundamental legal requirement for SIP
provisions, such as the requirement in section 302(k) that emission
limitations apply continuously, the EPA does not believe that such a
technical analysis is required.

    For example, section 302(k) does not differentiate between the
legal requirements applicable to SIP emission limitations for an annual
NAAQS versus for a 1-hour NAAQS, nor between any NAAQS based upon the
statistical form of the respective standards. In addition to being
supported by the text of section 302(k), the EPA's interpretation of
the requirement for sources to be subject to continuous emission
limitations is also the most logical given the consequences of the
commenters' theory. The commenters' argument provides additional
practical reasons to support the EPA's interpretation of the CAA to
preclude exemptions for emissions during SSM events from SIP emission
limitations as a basic legal requirement for all emission limitations.
    The EPA agrees that to ascertain the specific ambient impacts of
emissions during a given SSM event can sometimes be difficult. This
difficulty can be exacerbated by factors such as exemptions in SIP
provisions that not only excuse compliance with emission limitations
but also affect reporting or recordkeeping related to emissions during
SSM events. Determining specific impacts of emissions during SSM events
can be further complicated by the fact that the limited monitoring
network for the NAAQS in many states may make it more difficult to
establish that a given SSM event at a given source caused a specific
violation of the NAAQS. Even if a NAAQS violation is monitored, it may
be the result of emissions from multiple sources, including multiple
sources having an SSM event simultaneously. The different averaging
periods and statistical forms of the NAAQS may make it yet more
difficult to determine the impacts of specific SSM events at specific
sources, perhaps until years after the event occurred. By the
commenters' own logic, there could be situations in which it is
functionally impossible to demonstrate definitively that emissions
during a given SSM event at a single source caused a specific violation
of a specific NAAQS.
    The commenters' argument, taken to its logical extension, could
result in situations where a SIP emission limitation is only required
to be continuous for purposes of one NAAQS but not for another, based
on considerations such as averaging time or statistical form of the
NAAQS. Such situations could include illogical outcomes such as the
same emission limitation applicable to the same source simultaneously
being allowed to contain exemptions for emissions during SSM events for
one NAAQS but not for another. For example, purely hypothetically under
the commenters' premise, a given source could simultaneously be
required to comply with a rate-based NOX emission limitation
continuously for purposes of a 1-hour NO2 NAAQS but not be
required to do so for purposes of an annual NO2 NAAQS, or
the source could be required to comply continuously with the same NOx
limitation for purposes of the 8-hour ozone NAAQS and the 24-hour
PM2.5 NAAQS but not be required to do so for purposes of the
annual PM2.5 NAAQS. Add to this the further complication
that the source may be located in an area that is designated
nonattainment for some NAAQS and attainment for other NAAQS, and thus
subject to emission limitations for attainment and maintenance
requirements simultaneously.
    Under the commenters' premise, the same SIP emission limitation,
subject to the same statutory definition in section 302(k), could
validly include SSM exemptions for purposes of some NAAQS but not
others. Such a system of regulation would make it unnecessarily hard
for regulated entities, regulators and other parties to determine
whether a source is in compliance. The EPA does not believe that this
is a reasonable interpretation of the requirements of the CAA, nor of
its authority under section 110(k)(5). This unnecessary confusion is
easily resolved simply by interpreting the CAA to require that a source
subject to a SIP emission limitation for NOX must meet the
emission limitation continuously, in accordance with the express
requirement of section 302(k), thus making SSM exemptions
impermissible. The EPA does not agree that the term ``emission
limitation'' can reasonably be interpreted to allow noncontinuous
emission limitations for some NAAQS and not others. The D.C. Circuit
has already made clear that the term ``emission limitation'' means
limits that apply to sources continuously, without exemptions for SSM
events.
    Finally, the EPA disagrees with the specific arguments raised by
commenters concerning the modeling guidance for the 1-hour
NO2 NAAQS.\330\ As relevant here, that guidance provides
recommendations about specific issues that arise in modeling that is
used in the PSD program for purposes of demonstrating that proposed
construction will not cause or contribute to a violation of the 1-hour
NO2 NAAQS. Thus, as an initial matter, the EPA notes that
the context of that guidance relates to determining the extent of
emission reductions that a source needs to achieve in order to obtain a
permit under the PSD program, which is distinct from the question of
whether an emission limitation in a permit must assure continuous
emission reductions.
---------------------------------------------------------------------------

    \330\ See Memorandum, ``Additional Clarification Regarding
Application of Appendix W Modeling Guidance for the 1-hour
NO2 National Ambient Air Quality Standard,'' from T. Fox,
EPA/OAQPS, to Regional Air Division Directors, March 1, 2011.
---------------------------------------------------------------------------

    The commenters argued that this EPA guidance ``allows sources to
completely exclude all emissions during startup and shutdown
scenarios.'' This characterization is inaccurate for a number of
reasons. First, the guidance in question is only intended to address
certain modeling issues related to predictive modeling to demonstrate
that proposed construction will not cause or contribute to violation of
the 1-hour NO2 NAAQS, for purposes of determining whether a
PSD permit may be issued and whether the emission limitations in the
permit will require sufficient emission reductions to avoid a violation
of this standard.
    Second, to the extent that the guidance indicates that air quality
considerations might in certain circumstances and for certain purposes
be relevant to determining what emission limitations should apply to a
source, that does not mean a source may legally have an exemption from
compliance with existing emissions limitations during SSM events. In
the guidance cited by the commenter, the EPA did recommend that under
certain circumstances, it may be appropriate to model the projected
impact of the source on the NAAQS without taking into account
``intermittent'' emissions from sources such as emergency generators or
emissions from particular kinds of ``startup/shutdown''
operations.\331\ However, the EPA did not intend this to suggest that
emissions from sources during SSM events may validly be treated as
exempt in SIP emission limitations. Within the same guidance document,
the EPA stated unequivocally that the guidance ``has no effect on or
relevance to existing policies and guidance regarding excess emissions
that may occur during startup and shutdown.'' The EPA explained further
that ``all emissions from a new or modified source are subject to the
applicable permitted emission limits and may be subject to enforcement
concerning such excess emissions, regardless of whether a portion of
those emissions are not included in the modeling demonstration based on
the

guidance provided here.'' \332\ In other words, even if a state elects
not to include intermittent emissions from some types of startup and
shutdown events in certain modeling exercises, this does not mean that
sources can be excused from compliance with the emission limitation
during startup and shutdown, via an exemption for such emissions.
---------------------------------------------------------------------------

    \331\ Id. at 2.
    \332\ Id. at 11.
---------------------------------------------------------------------------

    Third, the guidance does not say that all SSM emissions may be
considered intermittent and excluded from the modeling demonstration.
The guidance explicitly recommends that the modeling be based on
``emission scenarios that can logically be assumed to be relatively
continuous or which occur frequently enough to contribute significantly
to the annual distribution of daily maximum 1-hour concentrations'' and
gives the example that it may be appropriate to include startup and
shutdown emissions from a peaking unit at a power plant in the modeling
demonstration because those units go through frequent startup/shutdown
cycles.\333\ Thus, the guidance does not support commenters' premise
that the EPA must evaluate the air quality impacts from SSM events in
SIP actions to determine that SSM exemptions in SIP provisions are
substantially inadequate to meet fundamental requirements of the CAA.
---------------------------------------------------------------------------

    \333\ Id. at 9.
---------------------------------------------------------------------------

    8. Comments that this SIP call action is inconsistent with 1976 EPA
guidance for such actions.
    Comment: One commenter argued that the EPA misinterpreted the term
``substantially inadequate'' in the February 2013 proposal because the
Agency is reading this term differently than in the past. In support of
this contention, the commenter pointed to a 1976 guidance document from
the EPA concerning the question of when a SIP may be substantially
inadequate. The commenter argued that the EPA is wrong to interpret
that term to mean anything other than a demonstrated failure to provide
for factual attainment of the NAAQS. According to the commenter, the
content of the 1976 guidance indicates that the EPA is obligated to
conduct a specific analysis to determine the air quality impact of an
alleged inadequacy in a SIP provision and to establish and document the
specific air quality impacts of the inadequacy.
    Response: The EPA disagrees with the commenter for multiple
reasons. First, the 1976 document referred to by the commenter was the
EPA's guidance on the requirements of the CAA as it was embodied in
1970, not as Congress substantially amended it in 1990. The 1976
guidance pertained not to the current SIP call provision at section
110(k)(5) but rather to the requirements of section 110(a)(2)(H). This
is particularly significant because the 1990 CAA Amendments added
section 110(k)(5) to the statute. Although section 110(a)(2)(H) remains
in the statute, it is primarily a requirement applicable to state
``infrastructure'' SIP obligations through which states are required to
have state law authority to meet the structural SIP elements required
in section 110(a)(2).\334\ In reviewing SIPs for compliance with
section 110(a)(2)(H), the EPA verifies that state SIPs include the
legal authority to respond to any SIP call. By contrast, the EPA's
authority to issue a SIP call under section 110(k)(5) is worded
broadly, explicitly including the authority to make a finding of
substantial inadequacy not only for failure to attain or maintain the
NAAQS but also for failures related to interstate transport or
``otherwise to comply with any requirement of'' the CAA.
---------------------------------------------------------------------------

    \334\ See Memorandum, ``Guidance on Infrastructure State
Implementation Plan (SIP) Elements under Clean Air Act Section
110(a)(1) and 110(a)(2),'' from Stephen D. Page, Director, OAQPS, to
Regional Air Directors, Regions 1-10, September 13, 2013, at page 51
(explaining that a state meets section 110(a)(2)(H) by having
authority to revise its SIP in response to a SIP call).
---------------------------------------------------------------------------

    Second, even setting aside that the guidance is not relevant to the
EPA's authority under section 110(k)(5), the 1976 guidance on its face
did not purport to define the full contours of the term ``substantially
inadequate'' in section 110(a)(2)(H). The 1976 guidance stated
explicitly that ``it is difficult to develop comprehensive guidelines
for all cases'' and only listed ``[s]ome factors that could be
considered'' in evaluating whether a state's SIP is substantially
inadequate.\335\ While the EPA acknowledges that these factors were
primarily focused upon ambient air considerations as suggested by the
commenter, they were not limited to that topic. Moreover, the EPA
stated that factors ``other than air quality and emission data must be
considered'' and provided several examples, including potential
amendments to the CAA under consideration at that point in time that
might change state SIP obligations and thus create the need for a SIP
call. More significantly, nothing in the 1976 guidance indicated that
the EPA should or would ignore legal deficiencies in existing SIP
provisions or that legal deficiencies are not relevant to the question
of whether a SIP would provide for attainment of the NAAQS.
---------------------------------------------------------------------------

    \335\ Id. at 10-11.
---------------------------------------------------------------------------

    Third, the EPA notes that the commenter did not advocate that the
Agency follow the 1976 guidance with respect to other issues, e.g.,
that the EPA would initiate the obligations of states to revise their
SIPs simply by making an announcement of substantial inadequacy
``without proposal''; that states would be required to make the
necessary SIP revision within 12 months; or that states should make
those revisions by no later than July 1, 1977.
    The EPA has fully articulated its interpretation of the term
``substantial inadequacy'' in section 110(k)(5) in the February 2013
proposal. As explained in the proposal, the EPA interprets its current
authority to include the issuance of a SIP call for the types of legal
deficiencies identified in this action. In order to establish that
these legal deficiencies are substantial inadequacies, the EPA does not
interpret section 110(k)(5) to require the Agency to document precisely
how each deficiency factually undermines the objectives of the CAA,
such as attainment and maintenance of the NAAQS in a particular
location on a particular date. It is sufficient that these provisions
are inconsistent with the legal requirements for SIP provisions set
forth in the CAA that are intended to assure that SIPs in fact do
achieve the intended objectives.
    10. Comments that because the EPA has misinterpreted the statutory
terms ``emission limitation'' and ``continuous,'' the EPA has not
established a substantial inadequacy.
    Comment: Many state and industry commenters disagreed with the
EPA's interpretation of the CAA to prohibit SSM exemptions in SIP
provisions. These arguments took many tacks, based on the
interpretation of various statutory provisions, the applicability of
the court decision in Sierra Club v. Johnson, alleged inconsistencies
related to this requirement in the EPA's own NSPS and NESHAP
regulations and a variety of other arguments. In particular, many
commenters argued that the EPA was misinterpreting the statutory terms
``emission limitation'' and ``continuous'' in section 302(k) to
preclude automatic or discretionary exemptions for emissions during SSM
events in SIP provisions. As an extension of these arguments,
commenters also argued that the EPA lacks authority under section
110(k)(5) to issue a SIP call when it has incorrectly interpreted a
relevant statutory term as the basis for finding a SIP provision to be
substantially inadequate.

    Response: The EPA disagrees that it lacks authority to issue this
SIP call on the grounds claimed by the commenters. As explained in
detail in the February 2013 proposal and in this final action, the EPA
has long interpreted the CAA to preclude SSM exemptions in SIP
provisions. This interpretation has been stated by the EPA since at
least 1982, reiterated in subsequent SSM Policy guidance documents,
applied in a number of notice and comment rulemakings and upheld by
courts.
    With respect to the arguments that the EPA has incorrectly
interpreted the terms ``emission limitation'' and ``continuous'' in
this action, the EPA has responded in detail in section VII.A.3 of this
document and need not repeat those responses here. In short, the EPA is
interpreting those terms consistent with the relevant statutory
language and consistent with the decision of the court in Sierra Club
v. Johnson. Because the specific SIP provisions identified in this
action with automatic or discretionary exemptions for emissions during
SSM events do not limit emissions from the affected sources
continuously, the EPA has found these provisions substantially
inadequate to meet CAA requirements in accordance with section
110(k)(5).
    11. Comments that section 110(k)(5) imposes a ``higher burden of
proof'' upon the EPA than section 110(l) and that section 110(l)
requires the EPA to conduct a specific technical analysis of the
impacts of a SIP revision.
    Comment: Commenters argued that the EPA is misinterpreting section
110(k)(5) to authorize a SIP call using a lower ``standard'' than the
section 110(l) ``standard'' that requires disapproval of a new SIP
provision in the first instance. The commenters stated that section
110(k)(5) requires a determination by the EPA that a SIP provision is
``substantially inadequate'' to meet CAA requirements in order to
authorize a SIP call, whereas section 110(l) provides that the EPA must
disapprove a SIP revision provision only if it ``would interfere with''
CAA requirements. Thus, the commenters asserted that ``the SIP call
standard is higher than the SIP revision standard.'' The commenters
further argued that it would be ``illogical and contrary to the CAA to
interpret section 110 to establish a lower standard for calling a
previously approved SIP and demanding revisions to it than for
disapproving that SIP in the first place.'' For purposes of section
110(l), the commenters claimed, the EPA ``is required'' to rely on
specific ``data and evidence'' that a given SIP revision would
interfere with CAA requirements and this requirement is thus imposed by
section 110(k)(5) as well. In support of this reasoning, the commenters
relied on prior court decisions pertaining to the requirements of
section 110(l).
    Response: The EPA disagrees with the commenters' interpretations of
the relative ``standards'' of section 110(k)(5) and section 110(l) and
with the commenters' views on the court decisions pertaining to section
110(l). In addition, the EPA notes that the commenters did not fully
address the related requirements of section 110(k)(3) concerning
approval and disapproval of SIP provisions, of section 302(k)
concerning requirements for emission limitations or of any other
sections of the CAA that are substantively germane to specific SIP
provisions and to enforcement of SIP provisions in general.\336\
---------------------------------------------------------------------------

    \336\ CAA section 110(k)(5) states that ``[w]henever the [EPA]
finds that the applicable implementation plan for any area is
substantially inadequate to attain or maintain the relevant [NAAQS],
to mitigate adequately [ ] interstate pollutant transport . . ., or
to otherwise comply with any requirement of [the CAA], the [EPA]
shall require the State to revise the plan as necessary to correct
such inadequacies.'' Section 110(l) states that, in the event a
state submits a SIP revision, the EPA ``shall not approve a revision
of a plan if the revision would interfere with any applicable
requirement concerning attainment and reasonable further progress .
. . or any other applicable requirement of [the CAA].'' Section
110(k)(3) states that the EPA ``shall approve such submittal . . .
if it meets all the requirements of [the CAA].''
---------------------------------------------------------------------------

    The commenters argued that, by the ``plain language'' of the CAA
and because of ``common sense,'' Congress intended the section
110(k)(5) SIP call standard to be ``higher'' than the section 110(l)
SIP revision. The EPA disagrees that this is a question resolved by the
``plain language.'' To the contrary, the three most relevant statutory
provisions, section 110(k)(3), section 110(l), and section 110(k)(5),
are each to some degree ambiguous and are likewise ambiguous with
respect to how they operate together to apply to newly submitted SIP
provisions versus existing SIP provisions. Section 110(k)(3) requires
the EPA to approve a newly submitted SIP provision ``if it meets all of
the applicable requirements of [the CAA].'' Implicitly, the EPA is
required to disapprove a SIP provision if it does not meet all
applicable CAA requirements. Section 110(l) provides that the EPA may
not approve any SIP revision that ``would interfere with . . . any
other applicable requirement of [the CAA].'' Section 110(k)(5) provides
that the EPA shall issue a SIP call ``whenever'' the Agency finds an
existing SIP provision ``substantially inadequate . . . to otherwise
comply with [the CAA].'' None of the core terms in each of the three
provisions is defined in the CAA. Thus, whether the ``would interfere
with'' standard of section 110(l) is per se a ``lower'' standard than
the ``substantially inadequate'' standard of section 110(k)(5) as
advocated by the commenters is not clear on the face of the statute,
and thus the EPA considers these terms ambiguous.
    As explained in detail in the February 2013 proposal, the EPA
interprets its authority under section 110(k)(5) broadly to include
authority to require a state to revise an existing SIP provision that
fails to meet fundamental legal requirements of the CAA.\337\ The
commenters raise a valid point that section 110(l) and section
110(k)(5), as well as section 110(k)(3), facially appear to impose
somewhat different standards. However, the EPA does not agree that the
proper comparison is necessarily between section 110(k)(5) and section
110(l) but instead would compare section 110(k)(5) and section
110(k)(3). Section 110(l) is primarily an ``anti-backsliding''
provision, meant to assure that if a state seeks to revise its SIP to
change existing SIP provisions that the EPA has previously determined
did meet CAA requirements, then there must be a showing that the
revision of the existing SIP provisions (e.g., a relaxation of an
emission limitation) would not interfere with attainment of the NAAQS,
reasonable further progress or any other requirement of the CAA. By
contrast, section 110(k)(3) is a more appropriate point of comparison
because it directs the EPA to approve a SIP provision ``that meets all
applicable requirements'' of the CAA and section 110(k)(5) authorizes
the EPA to issue a SIP call for previously approved SIP provisions that
it later determines do not ``comply with any requirement'' of the CAA.
---------------------------------------------------------------------------

    \337\ See February 2013 proposal, 78 FR 12459 at 12483-88.
---------------------------------------------------------------------------

    Notwithstanding that each of these three statutory provisions
applies to different stages of the SIP process, all three of them
explicitly make compliance with the legal requirements of the CAA a
part of the analysis. At a minimum, the EPA believes that Congress
intended these three sections, working together, to ensure that SIP
provisions must meet all applicable legal CAA requirements when they
are initially approved and to ensure that SIP provisions continue to
meet CAA requirements over time, allowing for potential amendments to
the CAA, changes in interpretation of the CAA by the EPA or courts or
simply changed facts. With respect to compliance with the applicable
legal requirements of the

CAA, the EPA does not interpret section 110(k)(5) as setting a per se
``higher'' standard. Under section 110(l), the EPA is likewise directed
not to approve a SIP revision that is not consistent with legal
requirements imposed by the CAA, including those relevant to SIP
provisions such as section 302(k). Pursuant to section 110(l), the EPA
would not be authorized to approve a SIP revision that contradicts
requirements of the CAA; pursuant to section 110(k)(5) the EPA is
authorized to direct states to correct a SIP provision that it later
determines does not meet the requirements of the CAA.
    The EPA also disagrees with the commenters' characterization of the
requirements of section 110(l) and their arguments based on court
decisions concerning section 110(l). Commenters rely on the decision in
Ky. Res Council v. EPA to support their argument that section 110(l)
requires the EPA to disapprove a SIP revision only if it ``would
interfere'' with a requirement of the CAA, not if it ``could
interfere'' with such requirements.\338\ From this decision, the
commenters argue that the EPA is required to conduct a specific
technical analysis under section 110(l) to determine the specific
impacts of the revision on attainment and maintenance of the NAAQS and
argue that by inference this must therefore also be required by section
110(k)(5). To the extent that court decisions concerning section 110(l)
are relevant, these court decisions do not support the commenters'
position.
---------------------------------------------------------------------------

    \338\ See 467 F.3d 986 (6th Cir. 2006).
---------------------------------------------------------------------------

    First, the EPA notes that the commenters mischaracterize section
110(l) as requiring a particular form or method of analysis to support
approval or disapproval of a SIP revision. Section 110(l) does not
contain any such explicit requirement or specifications. The EPA
interprets section 110(l) only to require an analysis that is
appropriate for the particular SIP revision at issue, and that analysis
can take different forms or different levels of complexity depending on
the facts and circumstances relevant to the SIP revision. Like section
110(l), the EPA believes that section 110(k)(5) does not specify a
particular form of analysis necessary to find a SIP provision
substantially inadequate.
    Second, the commenters mischaracterize the primary decision that
they rely upon. The court in Ky. Res Council v. EPA expressly discussed
the fact that section 110(l) does not specify precisely how any such
analysis should be conducted and deferred to the EPA's reasonable
interpretation of what form of analysis is appropriate for a given SIP
revision.\339\ Indeed, the decision stands for the proposition that the
EPA does not necessarily have to develop an attainment demonstration in
order to evaluate the impacts of a SIP revision, i.e. ``prove'' whether
the revision will interfere with attainment, maintenance, reasonable
further progress or any other requirements of the CAA. Thus, the
commenters' argument that section 110(k)(5) has to require a specific
technical analysis of impacts on attainment and maintenance because
section 110(l) does so is simply in error.
---------------------------------------------------------------------------

    \339\ See 467 F.3d at 995 (rejecting claim that section 110(l)
required a modeled attainment demonstration to prove that the SIP
revision would meet applicable CAA requirements).
---------------------------------------------------------------------------

    Third, the section 110(1) cases cited by the commenters did not
involve SIP revisions in which states sought to change existing SIP
provisions so that they would fail to meet the specific CAA
requirements at issue in this action. For example, none of the cases
involved the EPA's approval of a new automatic exemption for emissions
during SSM events. Had the state submitted a SIP revision that failed
to meet applicable requirements of the CAA for SIP provisions, such as
changing existing SIP emission limitations so that they would
thereafter include SSM exemptions, then the EPA would have had to
disapprove them.\340\ The challenged rulemaking actions at issue in the
cases relied upon by the commenters involved SIP revision changes
unrelated to the specific legal requirements at issue in this action.
Accordingly, the EPA's evaluation of those SIP revisions focused upon
other issues, such as whether the revision would factually result in
emissions that would interfere with attainment and maintenance of the
NAAQS, that were relevant to the particular provisions at issue in
those cases.
---------------------------------------------------------------------------

    \340\ The EPA notes that the one exception to this, of course,
is the Agency's recent approval of new SIP provisions in Texas that
created an affirmative defense for malfunctions. As discussed
elsewhere in this document, however, the EPA has determined that
such provisions do not meet CAA requirements and is thus issuing a
SIP call for those provisions.
---------------------------------------------------------------------------

    12. Comments that the EPA is misinterpreting US Magnesium and that
the decision provides no precedent for this action.
    Comment: A number of industry commenters argued that the EPA's
reliance on the decision of the Tenth Circuit in US Magnesium, LLP v.
EPA is misplaced.\341\ According to the commenters, the EPA did not
correctly interpret the decision and is misapplying it in acting upon
the Petition. The commenters asserted that the decision provides no
precedent for this action because it was decided upon issues different
from those at issue here. Commenters also argued that the court did not
reach an important issue because the petitioner had failed to comment
on it, i.e., the argument that the EPA had not defined the term
``substantially inadequate'' in the rulemaking.\342\
---------------------------------------------------------------------------

    \341\ See 690 F.3d 1157 (10th Cir. 2012).
    \342\ Id., 690 F.3d 1167, n.3.
---------------------------------------------------------------------------

    Response: The EPA disagrees with the commenters on this point. The
EPA of course acknowledges that the court in US Magnesium did not
address the full range of issues related to the correct treatment of
emissions during SSM events in SIP provisions that were raised in the
Petition, e.g., the court did not need to address the legal basis for
affirmative defense provisions in SIPs because of the nature of the SIP
provisions at issue in that case. However, the US Magnesium court
evaluated many of the same key questions raised in this rulemaking and
reached decisions that are very relevant to this action.
    First, the US Magnesium court specifically upheld the EPA's SIP
call action requiring the state to remove or revise a SIP provision
that included an automatic exemption for emissions from sources during
``upsets,'' i.e., malfunctions. In doing so, the court was fully aware
of the reasons why the EPA interprets the CAA to prohibit such
exemptions, because they violate statutory requirements including
section 302(k), section 110(a)(2)(A) and (C), and other requirements
related to attainment and maintenance of the NAAQS. The court explained
at length the EPA's reasoning about why the SIP provisions were
inconsistent with CAA requirements for SIP provisions.\343\
---------------------------------------------------------------------------

    \343\ Id., 690 F.3d at 1159-63.
---------------------------------------------------------------------------

    Second, the court specifically upheld the EPA's SIP call action
requiring the state to revise its SIP to remove or revise another SIP
provision that could be interpreted to give state personnel the
authority to determine unilaterally whether excess emissions from
sources are a violation of the applicable emission limitation and
thereby preclude any enforcement action by the EPA or citizens.
    Third, the court also upheld the EPA's authority to issue a SIP
call requiring a state ``to clarify language in the SIP that could be
read to violate the CAA, when a court has not yet interpreted the
language in that way.'' Indeed, the court opined that ``in light of the
potential conflicts'' between competing interpretations of the SIP
provision,

``seeking revision of the SIP was prudent, not arbitrary or
capricious.'' \344\
---------------------------------------------------------------------------

    \344\ Id., 690 F.3d at 1170.
---------------------------------------------------------------------------

    Fourth, the court explicitly upheld the EPA's reasonable
interpretation of section 110(k)(5) to authorize a SIP call when a
state's SIP provision is substantially inadequate to meet applicable
legal requirements, without making ``specific factual findings'' that
the deficient provision resulted in a NAAQS violation. The EPA
interpreted the CAA to allow a SIP call if the Agency ``determined that
aspects of the SIP undermine the fundamental integrity of the CAA's SIP
process and structure, regardless of whether or not the EPA could point
to specific instances where the SIP allowed violations of the NAAQS.''
The US Magnesium court explicitly agreed that section 110(k)(5)
authorizes issuance of a SIP call ``where the EPA determines that a SIP
is no longer consistent with the EPA's understanding of the CAA.''
\345\
---------------------------------------------------------------------------

    \345\ Id., 690 F.3d at 1168.
---------------------------------------------------------------------------

    Fifth, the court rejected claims that the EPA was requiring states
to comply with the SSM Policy guidance rather than the CAA
requirements, and the court noted that the Agency had undertaken
notice-and-comment rulemaking to evaluate whether the SIP provisions at
issue were consistent with CAA requirements.\346\
---------------------------------------------------------------------------

    \346\ Id., 690 F.3d at 1168.
---------------------------------------------------------------------------

    Sixth, the court rejected the claim that the EPA was interpreting
the requirements of the CAA incorrectly because the EPA is in the
process of bringing its own NSPS and NESHAP regulations into line with
CAA requirements for emission limitations, in accordance with the
Sierra Club v. Johnson decision.\347\ The court noted that the EPA is
now correcting SSM exemptions in its own regulations, and thus its
prior interpretation of the CAA, rejected by the court in Sierra Club
v. Johnson, did not make the SIP call to Utah arbitrary and
capricious.\348\
---------------------------------------------------------------------------

    \347\ Id., 690 F.3d at 1169.
    \348\ Id., 690 F.3d at 1170.
---------------------------------------------------------------------------

    On these and many other issues, the EPA believes that the court's
decision in US Magnesium provides an important and correct precedent
for the Agency's interpretation of the CAA in this action. The
commenters' apparent disagreement with the court does not mean that the
decision is not relevant to this action. The commenters specifically
argued that the US Magnesium court did not reach the issue of whether
the EPA had ``defined'' the term ``substantial inadequacy'' in the
challenged rulemaking because the petitioner had not raised this point
in comments. The EPA does not necessarily agree that ``defining'' the
full contours of the term is a necessary step for a SIP call, but
regardless of that fact the Agency did explain its interpretation of
the term ``substantial inadequacy'' with respect to the SIP provisions
at issue in the February 2013 proposal, the SNPR and this final action.
    13. Comments that EPA has to evaluate a SIP ``as a whole'' to have
the authority to issue a SIP call.
    Comment: Many state and industry commenters argued that the EPA
cannot evaluate individual SIP provisions in isolation and that the
Agency is required to evaluate the entire SIP and any related permit
requirements in order to determine if a specific SIP provision is
substantially inadequate. In particular, some commenters argued that
the EPA was wrong to focus upon the exemptions in SIP emission
limitations for emissions during SSM events without considering whether
some other requirement of the SIP or of a permit might operate to
override or otherwise modify the exemptions. Many of the commenters
asserted that other ``general duty'' clause requirements, elsewhere in
other SIP provisions or in permits for individual sources, make the SSM
exemptions in SIP emission limitations valid under the CAA.\349\ These
other requirements were often general duty-type standards that require
sources to minimize emissions, to exercise good engineering judgment or
not to cause a violation of the NAAQS. The implication of the
commenters' arguments is that such general-duty requirements legitimize
an SSM exemption in a SIP emission limitation--even if they are not
explicitly a component of the SIP provision, if they are not
incorporated by reference in the SIP provision and if they are not
adequate to meet the applicable substantive requirements for that type
of SIP provision.
---------------------------------------------------------------------------

    \349\ The EPA notes that other commenters on the February 2013
proposal made similar arguments with respect to affirmative defense
provisions in their SIPs, asserting that other SIP provisions or
terms in permits provided additional criteria that would have made
the affirmative defense provisions at issue consistent with the
EPA's interpretation of the CAA in the 1999 SSM Guidance. See, e.g.,
Comment from Virginia Department of Environmental Quality at 1-2, in
the rulemaking docket at EPA-HQ-OAR-2012-0322-0613. Because the EPA
no longer interprets the CAA to allow any affirmative defense
provisions, these comments are not germane.
---------------------------------------------------------------------------

    Response: The EPA disagrees with the basic premise of the
commenters that the EPA cannot issue a SIP call directing a state to
correct a facially deficient SIP provision without first determining
whether an unrelated and not cross-referenced provision of the SIP or
of a permit might potentially apply in such a way as to correct the
deficiency. As explained in section VII.A.3 of this document, the EPA
believes that all SIP provisions must meet applicable requirements of
the CAA, including the requirement that they apply continuously to
affected sources. In reviewing the specific SIP provisions identified
in the Petition, the EPA determined that many of the provisions include
explicit automatic or discretionary exemptions for emissions during SSM
events, whether as a component of an emission limitation or as a
provision that operates to override the otherwise applicable emission
limitation. Based on the EPA's review of these provisions, neither did
they apply ``continuously'' as required by section 302(k) nor did they
include cross-references to any other limitations that applied during
such exempt periods to potentially provide continuous limitations. To
the extent that the SIP of a state contained any other requirements
that applied during such periods, that fact was not plain on the face
of the SIP provision. If the EPA was unable to ascertain what, if
anything, applied during these explicitly exempt periods, then the
Agency concludes that regulated entities, members of and the public,
and the courts will have the same problem. The EPA has authority under
section 110(k)(5) to issue a SIP call requiring a state to clarify a
SIP provision that is ambiguous or unclear such that the provision can
lead to misunderstanding and thereby interfere with effective
enforcement.\350\
---------------------------------------------------------------------------

    \350\ See US Magnesium, LLC v. EPA, 690 F.3d 1157, 1169 (10th
Cir. 2012).
---------------------------------------------------------------------------

    To the extent that an affected state believes that the EPA has
overlooked another valid provision of the SIP that would cure the
substantial inadequacy that the Agency has identified in this action,
the state may seek to correct the deficient SIP provision by properly
revising it to remove the impermissible exemption or affirmative
defense and replacing it with the requirements of the other SIP
provision or by including a clear cross-reference that clarifies the
applicability of such provision as a component of the specific emission
limitation at issue. The state should make this revision in such a way
that the SIP emission limitation is clear on its face as to what the
affected sources are required to do during all modes of operation. The
emission limitation should apply continuously, and what is required by
the emission limitation under any mode of operation should be

readily ascertainable by the regulated entities, the regulators and the
public. The EPA emphasizes, however, that each revised SIP emission
limitation must meet the substantive requirements applicable to that
type of provision (e.g., impose RACM/RACT-level controls on sources
located in nonattainment areas) and must be legally and practically
enforceable (e.g., have sufficient recordkeeping, reporting and
monitoring requirements). The revised SIP emission limitation must be
consistent with all applicable CAA requirements.
    14. Comments that the EPA inappropriately is ``using guidance'' as
a basis for the SIP call action.
    Comment: State and industry commenters asserted that the EPA is
relying on guidance as the basis for issuing this SIP call action and
argued that the EPA cannot issue a SIP call based on guidance. The
commenters argued that the EPA guidance provided in the SSM Policy is
not binding and that states thus have the flexibility to develop SIP
provisions that are not in conformance with EPA guidance. Some
commenters claimed that if the EPA wishes to make the interpretations
of the CAA in its SSM Policy binding upon states, then it must do so
through a notice-and-comment rulemaking and must codify those
requirements in binding regulations in the CFR. The commenters argued
that states should not be subject to a SIP call for existing provisions
in their SIPs on the basis that they do not conform to guidance in the
SSM Policy. Some commenters acknowledged that the EPA is providing
notice and comment on its SSM Policy through this action, but still
they contended that the EPA's interpretation of the CAA is not binding
upon states unless the Agency codifies its updated SSM Policy in
regulations in the CFR.
    Response: The EPA disagrees with arguments that the Agency has
acted inappropriately by relying on its interpretations of the CAA set
forth in the SSM Policy in issuing this SIP call. As explained in the
February 2013 proposal, the SSM Policy is merely guidance. It is
correct that guidance documents are nonbinding. However, the guidance
provides the EPA's recommendations concerning how best to interpret the
statutory requirements of the CAA that are binding. Moreover, the EPA's
interpretation of the CAA in the SSM Policy can become binding once the
Agency adopts and applies that interpretation through notice-and-
comment rulemaking. The EPA is issuing this SIP call action through
notice-and-comment rulemaking and has specifically taken comment on its
interpretations of the CAA as they apply to the specific SIP provisions
at issue in this action. Thus, the EPA is requiring the affected states
to comply with the requirements of the CAA, not with the SSM Policy
guidance itself.\351\
---------------------------------------------------------------------------

    \351\ The EPA's reliance on interpretations of the CAA in the
SSM Policy through notice-and-comment rulemakings has previously
been upheld by several courts. See, e.g., US Magnesium, LLC v. EPA,
690 F.3d 1157, 1168 (10th Cir. 2012) (upholding the EPA's SIP call
to Utah for existing SIP provisions); Mich. Dep't of Envtl. Quality
v. Browner, 230 F.3d 181 (6th Cir. 2000) (upholding the EPA's
disapproval of a SIP submission).
---------------------------------------------------------------------------

    The EPA also disagrees with commenters that in order to rely on its
interpretation of the CAA in the SSM Policy, the EPA must first issue
regulatory provisions applicable to SIP provisions. There is no such
general obligation for the EPA to codify its interpretations of the CAA
in regulatory text. Unless Congress has specifically directed the EPA
to promulgate regulations for a particular purpose, the EPA has
authority and discretion to promulgate such regulations as it deems
necessary or helpful in accordance with its authority under section
301. With respect to issues concerning proper treatment of excess
emissions during SSM events in SIP provisions, the EPA has historically
proceeded by issuance of guidance documents. In this action, the EPA is
undergoing notice-and-comment rulemaking to update and revise its
guidance and to apply that guidance to specific existing SIP
provisions. Thus, the EPA is not required to promulgate specific
implementing regulations as a precondition to making a finding of
substantial inadequacy to address existing deficient SIP provisions.
    15. Comments that the EPA's redesignation and approval of a
maintenance plan for an area in a state with a SIP that has provisions
at issue in the SIP call establishes that all provisions in the SIP
meet CAA requirements.
    Comment: Commenters argued that the ``EPA's allegations that SSM
provisions could threaten the NAAQS is contradicted by'' the fact that
the ``EPA has consistently approved re-designation requests and
attainment and maintenance plans, notwithstanding SSM provisions.''
According to these commenters, ``[t]he fact that EPA has already
approved numerous re-designation requests . . . indicates that EPA has
already (and in many cases, very recently) admitted that the [State
SIPs are] fully approved, sufficient to achieve the NAAQS, and fully
enforceable.'' The commenters argued that the appropriate time for the
EPA to have addressed any issues concerning deficient SIP provisions
applicable to emissions during SSM events was ``in the context of its
review and approval of [maintenance] plans.'' Because the EPA has been
approving maintenance plans for areas in states subject to this SIP
call action, the commenters believed, this ``is evidence that the
Agency has not viewed SSM-related emissions as a threat to attainment
or maintenance of the NAAQS.'' In essence, these commenters argued that
the EPA's redesignation of any area in any of the states at issue in
this rulemaking indicates that the SIPs of these states fully meet all
CAA requirements and that there are no deficiencies whatsoever in the
SIPs of these states.
    Response: The EPA disagrees with the commenters' premise that the
Agency's approval of redesignation requests and maintenance plans for
certain nonattainment areas, notwithstanding the presence of
impermissible provisions related to emissions during SSM events that
may have been present in the SIP for those areas, is evidence that the
EPA does not view SSM-related emissions as a threat to attainment or
maintenance of the NAAQS. Contrary to the theory of the commenters, the
EPA's redesignation of an area to attainment does not mean that the SIP
for the state in question fully meets each and every requirement of the
CAA.
    The CAA sets forth the general criteria for redesignation of an
area from nonattainment to attainment in section 107(d)(3)(E). These
criteria include a determination by the EPA that the area has attained
the relevant standard (section 107(d)(3)(E)(i)) and that the EPA has
fully approved the applicable implementation plan for the area for
purposes of redesignation (section 107(d)(3)(E)(ii) and (v)). The EPA
must also determine that the improvement in air quality in the area is
due to reductions that are permanent and enforceable (section
107(d)(3)(E)(iii)) and that the EPA has fully approved a maintenance
plan for the area under section 175A (section 107(d)(3)(E)(iv)).
    For purposes of redesignation, the EPA has long held that SIP
requirements that are not linked with a particular nonattainment area's
designation and classification, including certain section 110
requirements, are not ``applicable'' for purposes of evaluating
compliance with the specific redesignation criteria in CAA sections
107(d)(3)(E)(ii) and (v).\352\ The EPA maintains this

interpretation because these requirements remain applicable after an
area is redesignated to attainment. For at least the past 15 years, the
EPA has applied this interpretation with respect to requirements to
which a state will continue to be subject after the area is
redesignated.\353\ Courts reviewing the EPA's interpretation of the
term ``applicable'' in section 107(d)(3) in the context of requirements
applicable for redesignation have generally agreed with the
Agency.\354\
---------------------------------------------------------------------------

    \352\ See, e.g., ``Approval and Promulgation of Implementation
Plans and Designation of Areas for Air Quality Planning Purposes;
State of Arizona; Redesignation of the Phoenix-Mesa Nonattainment
Area to Attainment for the 1997 8-Hour Ozone Standard; Proposed
rule,'' 79 FR 16734 at 16739 n.22 (March 26, 2014).
    \353\ See, e.g., 73 FR 22307 at 22312-13 (April 25, 2008)
(proposed redesignation of San Joaquin Valley; the EPA concluded
that section 110(a)(2)(D) transport requirements are not applicable
under section 110(d)(3)(E)(v) because they ``continue to apply to a
state regardless of the designation of any one particular area in
the state''); 62 FR 24826 at 24829-30 (May 7, 1997) (redesignation
of Reading, Pennsylvania, Area; the EPA concluded that the
additional controls required by section 184 were not ``applicable''
for purposes of section 107(d)(3)(E) because ``they remain in force
regardless of the area's redesignation status'').
    \354\ See Sierra Club v. EPA, 375 F.3d 537 (7th Cir. 2004); Wall
v. EPA, 265 F.3d 426, 438 (6th Cir. 2001). But see Sierra Club v.
EPA, Nos. 12-3169, 12-3182, 12-3420 (6th Cir. Mar. 18, 2015),
petition for reh'g en banc filed.
---------------------------------------------------------------------------

    The EPA therefore approves redesignation requests in many instances
without passing judgment on every part of a state's existing SIP, if it
finds those parts of the SIP are not ``applicable'' for purposes of
section 107(d)(3). For example, the EPA recently approved Arizona's
request to redesignate the Phoenix-Mesa 1997 8-hour ozone nonattainment
area and its accompanying maintenance plan, while recognizing that
Arizona's SIP may contain affirmative defense provisions that are not
consistent with CAA requirements.\355\ In that case, the EPA explicitly
noted that approval of the redesignation of the Phoenix-Mesa
nonattainment area did not relieve Arizona or Maricopa County of its
obligation to remove the affirmative defense provisions from the SIP,
if the EPA was to take later action to require correction of the
Arizona SIP with respect to those provisions.\356\
---------------------------------------------------------------------------

    \355\ 79 FR 55645 (September 17, 2014).
    \356\ Id. at 55648. The EPA notes that it has included the
deficient SIP provisions that include the affirmative defenses in
this action, thereby illustrating that it can take action to address
a SIP deficiency separately from the redesignation action, where
appropriate.
---------------------------------------------------------------------------

    The EPA also disagrees with commenters to the extent they suggest
that the Agency must use the redesignation process to evaluate whether
any existing SIP provisions are legally deficient. The EPA has other
statutory mechanisms through which to address existing deficiencies in
a state's SIP, and courts have agreed that the EPA retains the
authority to issue a SIP call to a state pursuant to CAA section
110(k)(5) even after redesignation of a nonattainment area in that
state.\357\ The EPA recently addressed this issue in the context of
redesignating the Ohio portion of the Huntington-Ashland (OH-WV-KY)
nonattainment area to attainment for the PM2.5 NAAQS.\358\
In response to comments challenging the proposed redesignation due to
the presence of certain SSM provisions in the Ohio SIP, the EPA
concluded that the provisions at issue did not provide a basis for
disapproving the redesignation request.\359\ In so concluding, the EPA
noted that the SSM provisions and related SIP limitations at issue in
that state were already approved into the SIP and thus ``permanent and
enforceable'' for the purposes of meeting section 107(d)(3)(E)(iii) and
that the Agency has other statutory mechanisms for addressing any
problems associated with the SSM provisions.\360\ The EPA emphasizes
that the redesignation of areas to attainment does not relieve states
of the responsibility to remove legally deficient SIP provisions either
independently or pursuant to a SIP call. To the contrary, the EPA
maintains that it may determine that deficient provisions such as
exemptions or affirmative defense provisions applicable to SSM events
are contrary to CAA requirements and take action to require correction
of those provisions even after an area is redesignated to attainment
for a specific NAAQS. This interpretation is consistent with prior
redesignation actions.
---------------------------------------------------------------------------

    \357\ See Southwestern Pennsylvania Growth Alliance v. EPA, 114
F.3d 984 (6th Cir. 1998) (Redesignation of Cleveland-Akron-Lorain
area determined valid even though the Agency subsequently proposed a
SIP call to require Ohio and other states to revise their SIPs to
mitigate ozone transport to other states).
    \358\ See 77 FR 76883 (December 31, 2012).
    \359\ Id. at 76891-92.
    \360\ The EPA notes that the provisions at issue in the
redesignation action are included in this SIP call, thus
illustrating that the Agency can address these deficient provisions
in a context other than a redesignation request.
---------------------------------------------------------------------------

    In some cases, the EPA has stated that the presence of illegal SSM
provisions does constitute grounds for denying a redesignation request.
For example, the EPA issued a proposed disapproval of Utah's
redesignation requests for Salt Lake County, Utah County and Ogden City
PM10 nonattainment areas.\361\ However, the specific basis
for the proposed disapproval in that action, which was one of many SIP
deficiencies identified by EPA, was the state's inclusion in the
submission of new provisions not previously in the SIP that would have
provided blanket exemptions from compliance with emission standards
during SSM events. Those SSM exemptions were not in the previously
approved SIP, and the EPA declined to approve them in connection with
the redesignation request because such provisions are inconsistent with
CAA requirements. In most redesignation actions, states have not sought
to create new SIP provisions that are inconsistent with CAA
requirements as part of their redesignation requests or maintenance
plans.
---------------------------------------------------------------------------

    \361\ 74 FR 62717 (December 1, 2009).
---------------------------------------------------------------------------

    Finally, the EPA disagrees with commenters that approval of a
maintenance plan for any area has the result of precluding the Agency
from later finding that certain SIP provisions are substantially
inadequate under the CAA on the basis that those provisions may
interfere with attainment or maintenance of the NAAQS or fail to meet
any other legal requirement of the CAA. The approval of a state's
redesignation request and maintenance plan for a particular NAAQS is
not the conclusion of the state's and the EPA's responsibilities under
the CAA but rather is one step in the process Congress established for
identifying and addressing the nation's air quality problems on a
continuing basis. The redesignation process allows states with
nonattainment areas that have attained the relevant NAAQS to provide
the EPA with a demonstration of the control measures that will keep the
area in attainment for 10 years, with the caveat that the suite of
measures may be revisited if necessary and must be revisited with a
second maintenance plan for the 10 years following the initial 10-year
maintenance period.
    Moreover, it is clear from the structure of section 175A
maintenance plans that Congress understood that the EPA's approval of a
maintenance plan is not a guarantee of future attainment air quality in
a nonattainment area. Rather, Congress foresaw that violations of the
NAAQS could occur following a redesignation of an area to attainment
and therefore required section 175A maintenance plans to include
contingency measures that a state could implement quickly in response
to a violation of a standard. The notion that the EPA's approval of a
maintenance plan must be the last word with regard to the contents of a
state's SIP simply does not comport with the framework Congress
established in the CAA for redesignations. The EPA has continuing
authority and responsibility to assure that a state's SIP meets CAA

requirements, even after approving a redesignation request for a
particular NAAQS.
    In conclusion, the EPA is not required to reevaluate the validity
of all previously approved SIP provisions as part of a redesignation.
The existence of provisions such as impermissible exemptions and
affirmative defenses applicable during SSM events in an approved SIP
does not preclude the EPA's determination that emission reductions that
have provided for attainment and that will provide for maintenance of a
NAAQS in a nonattainment area are ``permanent and enforceable,'' as
those terms are meant in section 107(d)(3), or that the state has met
all applicable requirements under section 110 and part D relevant for
the purposes of redesignation. Finally, if the EPA separately
determines that the state's SIP is deficient after the redesignation of
the area to attainment, the Agency can issue a SIP call requiring a
corrective SIP revision. Redesignation of areas to attainment in no way
relieves states of their continuing responsibilities to remove
deficient SIP provisions from their SIPs in the event of a SIP call.
    16. Comments that in issuing a SIP call the EPA is ``dictating'' to
states how to regulate their sources and taking away their discretion
to adopt appropriate control measures of their own choosing in
developing a SIP.
    Comment: Several commenters claimed that the EPA's SIP call action
removes discretion that states would otherwise have under the CAA.
Commenters claimed that the action has the effect of unlawfully
directing states to impose a particular control measure by requiring
the state to regulate all periods of operation for any source it
chooses to regulate. Because the alternative emission limitations and
work practice standards that the EPA asserts are necessary under the
statutory definition of ``emissions limitation'' are not real options
in some cases, the commenters claimed, the EPA's proposal is the type
of mandate that the court in the Virginia decision found to have
violated the CAA.\362\ Other commenters also cited to the Virginia
decision, as well as citing to the U.S. Supreme Court's decision in
Train v. NRDC, in which the Court held that ``so long as the ultimate
effect of a State's choice of emissions limitations is compliance with
the national standards, the State is at liberty to adopt whatever mix
of emissions limitations it deems best suited to its particular
situation.\363\ The commenters concluded that the EPA cannot prescribe
the specific terms of SIP provisions applicable to SSM events absent
evidence that the provisions undermine the NAAQS or are otherwise
inconsistent with the Act.
---------------------------------------------------------------------------

    \362\ 108 F.3d at 1410.
    \363\ 421 U.S. 60, 79 (1975).
---------------------------------------------------------------------------

    Commenters claimed that states are provided substantial discretion
under the Act in how to develop SIPs and that the EPA's SIP call action
is inconsistent with this long-recognized discretion because it limits
the states to one option: ``Eliminate any consideration of unavoidable
emissions during planned startups and shutdowns and adopt only an
extremely limited affirmative defense for unavoidable emissions during
a malfunction.'' The commenters claimed that other options available to
states include ``justifying existing provisions, adopting alternative
numeric emission limitations, work practice standards, additional
operational limitations, or revising existing numeric emission
limitations and/or their associated averaging times to create a
sufficient compliance margin for unavoidable SSM emissions.''
    The commenters further asserted that the EPA's February 2013
proposal contained inconsistent statements about how the Agency expects
states to respond to the SIP call. For example, according to one
commenter, the EPA states in one place that startup and shutdown
emissions above otherwise applicable limits must be considered a
violation yet elsewhere discusses the fact that states can adopt
alternative emission limitations for startup and shutdown. The
commenter also asserted that the EPA recommended that states could
elect to adopt the an approach to emissions during startup and shutdown
like that of the EPA's recent MATS rule but that the EPA then failed to
explain that the MATS rule contains ``exemptions'' for emissions during
startup and shutdown that apply so long as the source meets the general
work practice standards in the rule. This commenter claimed that the
EPA's own approach is inconsistent with statements in the February 2013
proposal that states should treat all startups and shutdowns as
``normal operations.''
    Response: The EPA disagrees with the commenter's claims that the
SIP call violates the structure of ``cooperative federalism'' that
Congress enacted for the SIP program in the CAA. Under this structure,
the EPA establishes NAAQS and reviews state plans to ensure that they
meet the requirements of the CAA. States take primary responsibility
for developing plans to attain and maintain the NAAQS, but the EPA is
required to step in if states fail to adopt plans that meet the
statutory requirements. As the court in Virginia recognized, Congress
gave states discretion in choosing the ``mix of controls'' necessary to
attain and maintain the NAAQS. See also Train v. NRDC, 421 U.S. 60, 79,
95 (1975). The U.S. Supreme Court first recognized this program of
cooperative federalism in Train, and the Court stated:

    The Act gives the Agency no authority to question the wisdom of
a State's choices of emissions limitations if they are part of a
plan which satisfies the standards of Sec.  110(a)(2) . . . [S]o
long as the ultimate effect of a State's choice of emissions
limitations is compliance with the national standards, the State is
at liberty to adopt whatever mix of emissions limitations it deems
best suited to its particular situation.

The issue in that case concerned whether changes to requirements that
would occur before the area was required to attain the NAAQS were
variances that should be addressed pursuant to the provision governing
SIP revisions or were ``postponements'' that must be addressed under
section 110(f) of the CAA of 1970, which contained prescriptive
criteria. The court concluded that the EPA reasonably interpreted
section 110(f) not to restrict a state's choice of the mix of control
measures needed to attain the NAAQS and that revisions to SIPs that
would not impact attainment of the NAAQS by the attainment date were
not subject to the limits of section 110(f). While the court recognized
that states had discretion in determining the appropriate emissions
limitations, it also recognized that the SIP must meet the standards of
section 110(a)(2). In Virginia, the issue was whether at the request of
the Ozone Transport Commission the EPA could mandate that states adopt
specific motor vehicle emission standards more stringent than those
mandated by CAA sections 177 and 202 for regulating emissions from
motor vehicles.
    As the EPA has consistently explained in its SSM Policy, the Agency
does not believe that exemptions from compliance with any applicable
SIP emission limitation requirements during periods of SSM are
consistent with the obligation of states in SIPs, including the
requirements to demonstrate that plans will attain and maintain the
NAAQS, protect PSD increments and improve visibility. If a source is
free from any obligation during periods of SSM, there is nothing
restraining those emissions and such emissions could cause or
contribute to an exceedance or violation of the NAAQS. Moreover,
neither the state nor citizens would have authority to take enforcement

action regarding such emissions. Also, even if historically such excess
emissions have not caused or contributed to an exceedance or violation,
this would not mean that they could not do so at some time in the
future. Finally, given that there are many locations where air quality
is not monitored such that a NAAQS exceedance or violation could be
observed, the inability to demonstrate that such excess emissions have
not caused or contributed to an exceedance or violation would not be
proof that they have not. Thus, the EPA has long held that exemptions
from emission limitations for emissions during SSM events are not
consistent with CAA requirements, including the obligation to attain
and maintain the NAAQS and the requirement to ensure adequate
enforcement authority.
    Despite claims by the commenter to the contrary, the EPA has not
mandated the specific means by which states should regulate emissions
from sources during startup and shutdown events. Requiring states to
ensure that periods of startup and shutdown are regulated consistent
with CAA requirements is not tantamount to prescribing the specific
means of control that the state must adopt. By the SIP call, the EPA
has simply explained the statutory boundaries to the states for SIP
provisions, and the next step is for the states to revise their SIPs
consistent with those boundaries. States remain free to choose the
``mix of controls,'' so long as the resulting SIP revisions meet CAA
requirements. The EPA agrees with the commenter who notes several
options available to the states in responding to the SIP call. The
commenter stated that there are various options available to states,
such as ``adopting alternative numeric emission limitations, work
practice standards, additional operational limitations, or revising
existing numeric emission limitations and/or their associated averaging
times to create a sufficient compliance margin for unavoidable SSM
emissions.'' However, the state must demonstrate how that mix of
controls for all periods of operation will ensure attainment and
maintenance of the NAAQS or meet other required goals of the CAA
relevant to the SIP provision, such as visibility protection. For
example, if a state chooses to modify averaging times in an emission
limitation to account for higher emissions during startup and shutdown,
the state would need to consider and demonstrate to the EPA how the
variability of emissions over that averaging period might affect
attainment and maintenance of a NAAQS with a short averaging period
(e.g., how a 30-day averaging period for emissions can ensure
attainment of an 8-hour NAAQS). One option noted by the commenter,
``justifying existing provisions,'' does not seem promising, based on
the evaluation that the EPA has performed as a basis for this SIP call
action. If by justification, the commenter simply means that the state
may seek to justify continuing to have an exemption for emissions
during SSM events, the EPA has already determined that this is
impermissible under CAA requirements.
    The EPA regrets any confusion that may have resulted from its
discussion in the preamble to the February 2013 proposal. The EPA's
statement that startup and shutdown emissions above otherwise
applicable limitations must be considered a violation is simply another
way of stating that states cannot exempt sources from complying with
emissions standards during periods of startup and shutdown. This is not
inconsistent with the EPA's statement that states can develop
alternative requirements for periods of startup and shutdown where
emission limitations that apply during steady-state operations could
not be feasibly met. In such a case, startup and shutdown emissions
would not be exempt from compliance but rather would be subject to a
different, but enforceable, standard. Then, only emissions that exceed
such alternative emission limitations would constitute violations.
    17. Comments that because areas are in attainment of the NAAQS, SIP
provisions such as automatic exemptions for excess emissions during SSM
events are rendered valid under the CAA.
    Comment: Commenters argued that SSM exemptions should be
permissible in SIP provisions applicable to areas designated attainment
because, they asserted, there is evidence that the exemptions do not
result in emissions that cause violations of the NAAQS. To support this
contention, the commenters observed that a number of states with SSM
exemptions in SIP provisions at issue in this SIP call are currently
designated attainment in all areas for one or all NAAQS and also that
some of these states had areas that previously were designated
nonattainment for a NAAQS but subsequently have come into attainment.
Thus, the commenters asserted, the SIP provisions that the EPA
identified as deficient due to SSM exemptions must instead be
consistent with CAA requirements because these states are in
attainment. The commenters claimed that because these areas have shown
they are able to attain and maintain the NAAQS or to achieve emission
reductions, despite SSM exemptions in their SIP provisions, the EPA's
concerns with respect to SSM exemptions are unsupported and
unwarranted. Based on the premise that SSM exemptions are not
inconsistent with CAA requirements applicable to areas that are
attaining the NAAQS, the commenters claimed that such provisions cannot
be substantially inadequate to meet CAA requirements.
    Response: The EPA disagrees with the commenters' view that, so long
as the provisions apply in areas designated attainment, the CAA allows
SIP provisions with exemptions for emissions during SSM events. The
commenters based their argument on the incorrect premise that SIP
provisions applicable to sources located in attainment areas do not
also have to meet fundamental CAA requirements such as sections
110(a)(2)(A), 110(a)(2)(C) and 302(k). Evidently, the commenters were
only thinking narrowly of the statutory requirements applicable to SIP
provisions in SIPs for purposes of part D attainment plans, which are
by design intended to address emissions from sources located in
nonattainment areas and to achieve attainment of the NAAQS in such
areas. The EPA does not interpret the fundamental statutory
requirements applicable to SIP provisions (e.g., that they impose
continuous emission limitations) to apply exclusively in nonattainment
areas; these requirements are relevant to SIP provisions in general.
    The statutory requirements applicable to SIPs are not limited to
areas designated nonattainment. To the contrary, section 107(a) imposes
the responsibility on each state to attain and maintain the NAAQS
``within the entire geographic areas comprising such State.'' The
requirement to maintain the NAAQS in section 107(a) clearly applies to
areas that are designated attainment, including those that may
previously have been designated nonattainment. Similarly, section
110(a)(1) explicitly requires states to have SIPs with provisions that
provide for the implementation, maintenance and enforcement of the
NAAQS. By inclusion of ``maintenance,'' section 110(a)(1) clearly
encompasses areas designated attainment as well as nonattainment. The
SIPs that states develop must also meet a number of more specific
requirements set forth in section 110(a)(2) and other sections of the
CAA relevant to particular air quality issues (e.g., the requirements
for attainment plans for the different NAAQS set out in more detail in
part D). Among those basic requirements that

states must meet in SIPS are section 110(a)(2)(C), requiring a
permitting program applicable to sources in areas designated
attainment, and section 110(a)(2)(D)(i)(II), requiring SIP provisions
to prevent interference with protection of air quality in areas
designated attainment in other states. Part C, in turn, imposes
additional requirements on states with respect to prevention of
significant deterioration of air quality in areas designated
attainment. Although the EPA agrees that the CAA distinguishes between,
and imposes different requirements upon, areas designated attainment
versus nonattainment, there is no indication that the statute
distinguishes between the basic requirements for emission limitations
in these areas, including that they be continuous.
    Section 110(a)(2)(A) requires states to include ``emission
limitations'' in their SIPs ``as may be necessary or appropriate to
meet applicable requirements of'' the CAA. The EPA notes that the
commenters have raised other arguments concerning the precise meeting
of ``necessary or appropriate'' (see section VII.A.3 of this document),
but in this context the Agency believes that because states are
required to have SIPs that provide for ``maintenance'' of the NAAQS it
is clear that the general requirements for emission limitations in SIPs
are not limited to areas designated nonattainment. Section 110(a)(2)(A)
contains no language distinguishing between emission limitations
applicable in attainment areas and emission limitations applicable in
nonattainment areas. Significantly, the definition of the term
``emission limitation'' in section 302(k) likewise makes no distinction
between requirements applicable to sources in attainment areas versus
nonattainment areas. The EPA sees no basis for interpreting the term
``emission limitation'' differently for attainment areas and
nonattainment areas, with respect to whether such emission limitations
must impose continuous controls on the affected sources. Most
importantly, section 110(a)(2)(A) does explicitly require that any such
emission limitations must ``meet the applicable requirements'' of the
CAA, and the EPA interprets this to include the requirement that
emission limitations apply continuously, i.e., contain no exemptions
for emissions during SSM events. This requirement applies equally in
all areas, including attainment and nonattainment areas.
    The EPA's interpretation of the CAA in the SSM Policy has long
extended to SIP provisions applicable to attainment areas as well as to
nonattainment areas. Since at least 1982, the SSM Policy has stated
that SIP provisions with SSM exemptions are inconsistent with
requirements of the CAA to provide both for attainment and maintenance
of the NAAQS, i.e., inconsistent with requirements applicable to both
nonattainment and attainment areas.\364\ Since at least 1999, the EPA's
SSM Policy has clearly stated that SIP provisions with SSM exemptions
are inconsistent with protection of PSD increments in attainment
areas.\365\ The EPA provided its full statutory analysis with respect
to SSM exemptions and CAA requirements applicable to areas designated
attainment in the background memorandum accompanying the February 2013
proposal.\366\
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    \364\ See 1982 SSM Guidance, Attachment at 1.
    \365\ See 1999 SSM Guidance at 2.
    \366\ See Memorandum, ``Statutory, Regulatory, and Policy
Context for this Rulemaking,'' February 4, 2013, in the rulemaking
docket at EPA-HQ-OAR-2012-0322-0029.
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    Finally, the EPA disagrees with the commenters' theory that, absent
proof that the SIP deficiency has caused or will cause a specific
violation of the NAAQS, the Agency lacks authority to issue a SIP call
for SIP provisions that apply only in areas attaining the NAAQS. This
argument is inconsistent with the plain language of section 110(k)(5).
Section 110(k)(5) authorizes the EPA to issue a SIP call whenever the
SIP is substantially inadequate to attain or maintain the NAAQS, to
mitigate interstate transport or to comply with any other CAA
requirement. The explicit reference to a SIP's being inadequate to
maintain the NAAQS clearly indicates that the EPA has authority to make
a finding of substantial inadequacy for a SIP provision applicable to
attainment areas, not only for a SIP provision applicable to
nonattainment areas. In addition, section 110(k)(5) explicitly
authorizes the EPA to issue a SIP call not only in instances related to
a specific violation of the NAAQS but rather whenever the Agency
determines that a SIP provision is inadequate to meet requirements
related to attainment and maintenance of the NAAQS or any other
applicable requirement of the Act, including when the provision is
inadequate to meet the fundamental legal requirements applicable to SIP
provisions. Were the EPA's authority limited to issuing a SIP call only
in the event an area was violating the NAAQS, section 110(k)(5) would
not explicitly include requirements related to ``maintenance'' and
would not explicitly include the statement ``otherwise comply with any
requirement of [the CAA].''
    18. Comments that the EPA's initial approval of these deficient
provisions, or subsequent indirect approval of them through action on
other SIP submissions, establishes that these provisions meet CAA
requirements.
    Comment: A number of commenters argued that because the EPA
initially approved the SIP provisions at issue in this rulemaking, this
establishes that these provisions meet CAA requirements. Other
commenters argued that subsequent actions on other SIP submissions in
effect override the fact that the SIP provisions at issue are legally
deficient. For example, an industry commenter asserted that there have
been ``dozens of instances where EPA has reviewed Alabama SIP revision
submittals'' and the EPA has never indicated ``that it believed these
rules to be inconsistent with the CAA.'' Other state commenters made
similar arguments suggesting that the EPA's original approval of these
provisions, and the fact that the EPA has not previously taken action
to require states to revise them, indicates that they are not
deficient.
    Response: The EPA disagrees with these commenters. The fact that
the EPA once approved a SIP provision does not mean that the SIP
provision is per se consistent with the CAA, or consistent with the CAA
notwithstanding any later legal or factual developments. This is
demonstrated by the very existence of the SIP call provision in section
110(k)(5), whereby the EPA may find that an ``applicable implementation
plan for any area is substantially inadequate to attain or maintain the
relevant [NAAQS] . . . or to otherwise comply with any requirement of''
the CAA. This SIP call authority expressly authorizes the EPA to direct
a state to revise its SIP to remedy any substantial inadequacy,
including failures to comply with legal requirements of the CAA. By
definition, when the EPA promulgates a SIP call, this means that the
Agency has previously approved the provision into the SIP, rightly or
wrongly. The SIP call provision would be meaningless if a SIP provision
were considered perpetually consistent with CAA requirements after it
was originally approved, and merely because of that prior approval as
commenters suggest. In the February 2013 proposal, the EPA acknowledged
its own responsibility in approving provisions that were inconsistent
with CAA requirements.
    The EPA also disagrees with the argument that the Agency's action
on other intervening SIP submissions from a state over the years since
the approval

of the original deficient SIP provision in some way negates the
original deficiency. The industry commenter pointed to ``dozens of
instances where EPA reviewed Alabama SIP revision submittals'' as times
when the EPA should have addressed any SSM-related deficient SIP
provisions. However, the EPA's approval of other SIP revisions does not
necessarily entail reexamination and reapproval of every provision in
the SIP. The EPA often only examines the specific provision the state
seeks to revise in the SIP submission without reexamining all other
provisions in the SIP. The EPA sometimes broadens its review if
commenters bring other concerns to the Agency's attention during the
rulemaking process that are relevant to the SIP submission under
evaluation.
    19. Comments that exemptions for excess emissions during exempt SSM
events would not distort emissions inventories, SIP control measure
development or modeling, because the EPA's regulations and guidance
concerning ``rule effectiveness'' adequately account for these
emissions, and therefore the proposed SIP calls are not needed or
justified.
    Comment: One commenter argued that provisions allowing exemptions
or affirmative defenses for excess emissions during startup and
shutdown are consistent with a state's authority under CAA section 110
and that this is evidenced by the fact that the EPA has issued guidance
on ``rule effectiveness'' that plainly takes into account a
``discount'' factor in a state's demonstration of attainment when it
chooses to adopt startup/shutdown provisions. This commenter cited the
EPA's definition of ``rule effectiveness'' at 40 CFR 51.50 and EPA
guidance on demonstrating attainment of PM2.5 and regional
haze air quality goals.\367\
---------------------------------------------------------------------------

    \367\ The commenter appears to have been meaning to cite to the
draft EPA guidance document ``Draft Guidance for Demonstrating
Attainment of Air Quality Goals for PM2.5 and Regional
Haze,'' January 2, 2001. This draft guidance on PM2.5 and
Regional Haze was combined with similar guidance on ozone in the
final guidance document ``Guidance on the Use of Models and Other
Analyses for Demonstrating Attainment of Air Quality Goals for
Ozone, PM2.5, and Regional Haze,'' April 2007, EPA-454/B-
07-002.
---------------------------------------------------------------------------

    Response: The EPA disagrees with the characterization in this
comment of past EPA guidance and with the conclusion that the fact of
the existence of EPA guidance on ``rule effectiveness'' would support
the claim that the CAA provides authority for exemptions or affirmative
defenses for excess emissions during startup and shutdown. The EPA's
definition of ``rule effectiveness'' at 40 CFR 51.50 does not refer to
startup and shutdown; it refers only to ``downtime, upsets, decreases
in control efficiencies, and other deficiencies in emission
estimates,'' and once defined the term ``rule effectiveness'' is not
subsequently used within 40 CFR part 51 in any way that would indicate
that it is meant to capture the effect of exemptions during startup and
shutdown. The EPA guidance on demonstrating attainment of
PM2.5 and regional haze goals cited by the commenter also
does not address rule effectiveness or excess emissions during startup
and shutdown. The terms ``startup'' and ``shutdown'' do not appear in
the attainment demonstration guidance. The EPA did issue a different
guidance document in 1992 on rule effectiveness,\368\ but that document
focused only on the preparation of emissions inventories for 1990, not
on demonstrating attainment of NAAQS or regional haze goals. Moreover,
the 1992 guidance document addressed ways of estimating actual 1990
emissions in light of the likelihood of a degree of source
noncompliance with applicable emission limitations, not on the
emissions that would be permissible in light of the absence of a
continuous emission limitation applicable during startup and shutdown.
The terms ``startup'' and ``shutdown'' do not appear in the 1992
guidance. In 2005, the EPA replaced the 1992 guidance document on rule
effectiveness as part of providing guidance for the implementation of
the 1997 ozone and PM2.5 NAAQS.\369\ Like the 1992 guidance,
the 2005 guidance associated ``rule effectiveness'' with the issue of
noncompliance and did not provide any specific advice on quantifying
emissions that could be legally emitted because of SSM exemptions in
SIPs. To avoid misunderstanding, the 2005 guidance included a question
and answer on startup and shutdown emissions to the effect that
emissions during startup and shutdown should be included in ``actual
emissions.'' This question and answer included the statement, ``[L]ess
preferably, [emissions during startup, shutdown, upsets and
malfunctions] can be accounted for using the rule effectiveness
adjustment procedures outlined in this guidance.'' However, other than
in this question and answer, the 2005 guidance does not mention
emissions during startup and shutdown events; it focuses on issues of
noncompliance with applicable emission limitations. The fact that the
1992 guidance document did not intend for ``rule effectiveness'' to
encompass SIP-exempted emissions during startup and shutdown, and that