in a standard of performance that is no less stringent than necessary
to address the fundamental differences and that meet the applicable
requirements. When a state invokes RULOF and applies a less-stringent
standard, it must demonstrate that the standard is no less stringent
than necessary to address the fundamental difference identified by the
state. Absent such a demonstration, the EPA cannot ascertain that a
less-stringent standard meets the requirements of CAA section 111; that
is, it cannot determine that a less-stringent standard is
``satisfactory.''
    The requirements proposed at 40 CFR 60.24a(j) were intended to
explicitly clarify states' responsibilities when invoking RULOF and to
assist them in developing standards in a manner that enables the Agency
to determine whether such standards are ``satisfactory.'' The proposed
requirements provided that states would carry the burden of making any
demonstrations in support of less-stringent standards pursuant to the
RULOF provisions. States would carry the primary responsibility to
develop plans that meet the requirements of CAA section 111(d) and
therefore have the obligation to justify any accounting for RULOF in
support of standards less stringent than those provided by the EG.
While the EPA has discretion to supplement a state's demonstration, the
Agency may also find that a state plan's failure to include a
sufficient RULOF demonstration is a basis for concluding the plan is
not ``satisfactory'' and therefore disapprove the plan. The EPA further
proposed that for the required demonstrations, states must use
information that is applicable to and appropriate for the specific
designated facility, and must show how information is applicable and
appropriate. As RULOF is a source-specific determination, it is
appropriate to require that the information used to justify a less
stringent standard for a particular designated facility be applicable
to and appropriate for that source. Finally, the EPA proposed to
require that the information used for states' demonstrations under the
new RULOF provisions must come from reliable and adequately documented
sources, such as EPA sources and publications, permits, environmental
consultants, control technology vendors, and inspection reports.
    Comments received on the proposed requirements regarding states'
burden of demonstration and the use of site-specific information were
generally supportive while also requesting further clarification of and
flexibility in the types of information that the EPA would consider
acceptable. One commenter suggested that the EPA allow states to use
historical data even if not published or documented by third parties,
as this constitutes site-specific information, while another suggested
allowing verified industry information, even if it is not site-
specific.
    Despite the generally supportive commenters received, the EPA is
not finalizing the requirements proposed at 40 CFR 60.24a(j). While the
EPA continues to find that states carry the burden of making any
demonstrations in support of less-stringent standards pursuant to RULOF
in developing their plans, we have determined that it is not necessary
to promulgate this expectation as a standalone regulatory requirement.
States always bear the responsibility of reasonably documenting and
justifying the standards of performance in their plans.\141\ If the EPA
cannot ascertain, based on the information and analysis included in a
state plan submission, whether a standard of performance meets the
statutory requirements, it cannot find that standard satisfactory.
Additionally, it is de facto necessary to use information that is
applicable to and appropriate for the designated facility when
analyzing systems of emission reduction for that particular facility.
For example, for a designated facility invoking RULOF based on its
unique design features, the state plan must provide information
corroborating the uniqueness of those features and analysis
demonstrating how they result in the facility being unable to
reasonably achieve the degree of emission limitation determined by the
EPA. It would not be reasonable in this instance for a state to use
generic industry data, whether verified or not, as the basis of
demonstrations pursuant to 40 CFR 60.24a(e) and (f).
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    \141\ Where a state has relied on information or analyses the
EPA provided in an applicable EG as part of its source specific BSER
determination, a state would explain why such reliance is reasonable
and cite or otherwise incorporate that information or analyses in
its state plan submission.
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    While the proposed requirements would have simply codified
generally applicable tenets of reasoned decision making, the EPA
recognizes that the specific types and provenances of information
needed to justify a less-stringent standard can vary significantly
between not only source categories, but between individual designated
facilities within a source category. As a result, the proposed
provisions had the potential to be both over- and underinclusive. While
we are not finalizing these provisions as generally applicable
requirements for state plans, they and the accompanying discussion in
the notice of proposed rulemaking \142\ remain important guidance for
plan development. The EPA may also choose to promulgate requirements
for RULOF demonstrations in individual EGs.
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    \142\ See 87 FR 79176, 79202-03 (Dec. 23, 2022).
---------------------------------------------------------------------------

f. Consideration of Impacted Communities
    While the consideration of RULOF can be warranted to apply a less
stringent standard of performance to a particular facility, such
standards have the potential to result in disparate health and
environmental impacts to communities most affected by and vulnerable to
those impacts from the designated facilities being addressed by the
state plan. These communities could be put in the position of bearing
the brunt of the greater health or environmental impacts resulting from
that source implementing less stringent emission controls than would
otherwise have been required pursuant to the EG. The EPA considers that
a lack of attention to such potential outcomes would be antithetical to
the public health and welfare goals of CAA section 111(d) and the CAA
generally. Because of CAA section 111(d)(2)'s requirement that the EPA
determine whether a state plan is ``satisfactory'' applies to such
plan's consideration of RULOF in applying a standard of performance to
a particular facility, the EPA must determine whether a plan's
consideration of RULOF is consistent with CAA section 111(d)'s overall
health and welfare objectives.
    In order to address the potential exacerbation of health and
environmental impacts to these communities as a result of applying a
less stringent standard, the EPA proposed to require states to consider
such impacts when applying the RULOF provision to establish those
standards. Under the proposed provisions at 40 CFR 60.24a(k), to the
extent a designated facility would qualify for a less stringent
standard through

consideration of RULOF, the state, in calculating such standard, would
have been required to demonstrate consideration of the potential health
and environmental impacts and potential benefits of control to
communities most affected by and vulnerable to the impacts from the
designated facility considered in a state plan for RULOF provisions.
These communities will be identified by the state as pertinent
stakeholders under the finalized meaningful engagement completeness
requirements described in section III.C. of this preamble.
    The notice of proposed rulemaking further explained that state plan
submissions seeking to invoke RULOF for a source would be required to
identify where and how a less stringent standard impacts these
communities. In evaluating a RULOF option for a facility, states should
describe the health and environmental impacts anticipated from the
application of RULOF for such communities, along with any feedback the
state received during meaningful engagement regarding its draft state
plan submission, including on any standards of performance that
consider RULOF. Additionally, to the extent there is a range of options
for reasonably controlling a source based on RULOF, the EPA proposed
that in determining the appropriate standard of performance, states
should consider the health and environmental impacts to the communities
most affected by and vulnerable to the impacts from the designated
facility considered in a state plan for RULOF provisions and provide in
the state plan submission a summary of the results that depicts
potential impacts for those communities for that range of reasonable
control options.
    The EPA received a wide range of comments on the proposed
requirements for state plans to consider the potential pollution
impacts and benefits of control to communities most affected by and
vulnerable to emissions from a designated facility that is invoking
RULOF. Several commenters supported the proposal and agreed that, given
that the purpose of regulating stationary source pollution under CAA
section 111 is to address emissions that endanger public health and
welfare, requiring states that are applying less-stringent standards to
take into account how air pollution above the level reflected by
application of the BSER may impact the health and welfare of local
communities furthers the statutory design. Other commenters agreed that
the EPA has authority to require states to consider the impacts of
less-stringent standards of performance on vulnerable communities but
expressed concern that the lack of specificity of and guidance for
implementing the proposed requirements would cause uncertainty among
state regulators and impacted communities and lead to unequal
application across states. Similarly, one commenter noted the
differences between community impacts when considering localized
pollutants versus regional or global pollutants and that impacts of the
latter are more diffuse and difficult to assess. Some commenters,
however, disagreed that the EPA has authority to require states to
consider potential health and environmental impacts of less-stringent
standards on vulnerable communities. These commenters generally
asserted that the state-focused language of the RULOF provision in CAA
section 111(d)(1) does not mandate an analysis of vulnerable
communities and does not give the EPA power to force states to consider
``other factors'' that it deems relevant.
    The EPA is not finalizing the proposed provisions at 40 CFR
60.24a(k) as requirements under the general implementing regulations.
We agree with commenters that additional specificity and guidance with
regard to how states should consider the potential pollution impacts
and benefits of control to communities most affected by and vulnerable
to emissions from a designated facility invoking RULOF would be key to
ensuring meaningful implementation of this provision. However, given
the diversity of source categories, designated facilities, and
designated pollutants that are regulated and could be regulated in CAA
section 111(d), as well as the wide range of potential impacts on
vulnerable communities that may result from less-stringent standards of
performance under any given EG,\143\ the EPA does not believe it is
either feasible or appropriate to prescribe a universally applicable
approach or standard for approvability for this consideration. Instead,
to protect all communities, including the most vulnerable ones, the EPA
is finalizing a provision that will ensure that any less stringent
standards of performance applied by states are no less stringent than
necessary. Moreover, because consideration of health and environmental
impacts is inherent in consideration of both the nonair quality health
and environmental impacts and amount of emission reduction factors the
EPA considers under CAA section 111(a)(1), when a state considers the
systems of emission reduction identified in the applicable emission
guideline using the factors and evaluation metrics the EPA considered
in assessing those systems pursuant to RULOF, the state will
necessarily consider the potential impacts and benefits of control to
communities affected by a designated facility that is receiving a less-
stringent standard of performance.
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    \143\ In the notice of proposed rulemaking, the EPA
``recognize[d] that the consideration of communities in the standard
setting process, such as what constitutes a benefit to a vulnerable
community and what is a reasonable level of control, is highly
dependent on the designated pollutant and source category subject to
an EG.'' 87 FR 79203.
---------------------------------------------------------------------------

    Thus, while the EPA is not promulgating a regulatory requirement in
subpart Ba for states to consider the impacts of applying a less-
stringent standard of performance on the communities most affected by
and vulnerable to emissions from a designated facility invoking RULOF,
the EPA anticipates that states will consider these impacts. To this
end, states may look to the EPA's emission guideline and its
consideration of nonair quality health and environmental impacts and
the amount of emission reductions available in determining the degree
of emission limitation for guidance on considering the health and
environmental impacts on communities affected by a designated facility
for which RULOF has been invoked. Additionally, the procedural
requirements under subpart Ba for meaningful engagement with pertinent
stakeholders on state plan development that the EPA is finalizing will
play an important role in RULOF. Meaningful engagement, which the EPA
is defining as ``timely engagement with pertinent stakeholder
representation in the plan development or plan revision process,''
\144\ and providing that ``[s]uch engagement should not be
disproportionate in favor of certain stakeholders and should be
informed by available best practices,'' should address, inter alia, the
application of any less-stringent standards of performance pursuant to
RULOF. Thus, the EPA intends for communities most affected by and
vulnerable to the health and environmental impacts of pollution from a
designated facility invoking RULOF to have an opportunity to
participate in the process of determining how that facility is
addressed in the relevant state plan. The EPA may also consider whether
to promulgate requirements pertaining to consideration of impacts on
vulnerable communities as part of an individual EG in the future, at
which point it would

provide guidance on how to do so specific to the designated facilities
and designated pollutant at issue.
---------------------------------------------------------------------------

    \144\ The EPA is also finalizing the proposed definition of
``pertinent stakeholders'' to include those who are most affected by
and vulnerable to the health or environmental impacts of pollution
from the designated facilities addressed by the plan or plan
revision.
---------------------------------------------------------------------------

g. Authority To Apply More Stringent Standards as Part of the State
Plan
    The EPA, in the notice of proposed rulemaking, addressed two
different sources of authority that would allow the Agency to approve
state plans that include standards of performance that are more
stringent than the degree of emission limitation determined by the EPA
in the applicable EG. First, the EPA explained that allowing states to
apply a more stringent standard of performance as part of their CAA
section 111(d) plans is consistent with CAA section 116, which
generally authorizes states to include more stringent standards of
performance or requirements regarding control or abatement of air
pollution in their plans. Second, the EPA proposed to interpretation
the RULOF provision in CAA section 111(d)(1), and specifically the
``other factors'' consideration, as allowing states to adopt more
stringent standards of performance.\145\ As explained below, the EPA is
not finalizing its proposed interpretation that states can use the
RULOF provision in CAA section 111(d)(1) to adopt, and have the EPA
approve, more stringent standards of performance in their state plans
because, inter alia, states already have the authority and ability to
do so under CAA section 116.
---------------------------------------------------------------------------

    \145\ 87 FR 79204-06.
---------------------------------------------------------------------------

    As explained in the notice of proposed rulemaking, the anti-
preemption requirements of CAA section 116 provide that nothing in the
statute shall preclude or deny the right of states to adopt or enforce
``any standard or limitation respecting emissions of air pollutants.''
While CAA section 116 clearly extends to a state adopting or enforcing
a standard of performance more stringent than required under CAA
section 111(d), the subpart Ba implementing regulations did not
explicitly speak to whether the EPA can approve a state plan that
includes such standard of performance. However, the EPA proposed to
find that CAA section 116, as interpreted through the Supreme Court in
Union Electric Co. v. EPA,\146\ requires the EPA to approve a state
plan that includes more stringent standards of performance under CAA
section 111(d). The EPA therefore proposed to modify the existing 40
CFR 60.24a(f),\147\ clarifying that to the extent a state chooses to
submit a plan that includes standards of performance that are more
stringent or compliance schedules that are more rapid than the
requirements of an EG, states have the authority to do so under this
provision and CAA section 116. Further, the EPA proposed to clarify
that it has the obligation, and therefore the authority, to review and
approve such plans and render the more stringent requirements federally
enforceable if all applicable requirements are met.
---------------------------------------------------------------------------

    \146\ 427 U.S. 246, 263-64 (1976).
    \147\ The existing provision at 40 CFR 60.24a(f) provides that
``[n]othing in this subpart shall be construed to preclude any State
or political subdivision thereof from adopting or enforcing,'' (1)
standards of performance more stringent than an EG, or (2)
compliance schedules requiring final compliance at earlier times
than specified in an EG. In the proposed rulemaking, the EPA added
several proposed provisions to 40 CFR 60.24a, which resulted in
Sec.  60.24a(f), in addition to being amended, being renumbered as
Sec.  60.24a(n). However, the EPA is not finalizing all the new
provisions it proposed; as a result, erstwhile Sec.  60.24a(f) is
now being finalized, with amendments, at Sec.  60.24a(i).
---------------------------------------------------------------------------

    The EPA is finalizing the proposed changes to the provision
currently at 40 CFR 60.24a(f) which, as renumbered pursuant to this
final rule, is now 40 CFR 60.24a(i). The Agency acknowledges that it
previously took the position in the ACE Rule that Union Electric does
not control the question of whether CAA section 111(d) state plans may
be more stringent than Federal requirements. The EPA took this position
in the ACE Rule on the basis that Union Electric on its face applies
only to CAA section 110, and that it is ``potentially salient'' that
CAA section 111(d) is predicated on specific technologies whereas CAA
section 110 gives states broad latitude in the measures used for
attaining the NAAQS.\148\ The EPA no longer takes this position. Upon
further evaluation, the EPA finds that, because of the structural
similarities between CAA sections 110 and 111(d), CAA section 116 as
interpreted by Union Electric requires the EPA to approve CAA section
111(d) state plans that are more stringent than required by the EG.
---------------------------------------------------------------------------

    \148\ 84 FR 32559-61.
---------------------------------------------------------------------------

    The Court in Union Electric rejected a construction of CAA sections
110 and 116 that measures more stringent than those required to attain
the NAAQS cannot be approved into a federally enforceable SIP but can
be adopted and enforced only as a matter of state law. The Court found
that such an interpretation of CAA section 116 ``would not only require
the Administrator to expend considerable time and energy determining
whether a state plan was precisely tailored to meet the Federal
standards but would simultaneously require States desiring stricter
standards to enact and enforce two sets of emission standards, one
federally approved plan and one stricter state plan.'' 427 U.S. at 263-
64. The Court concluded there was no basis ``for visiting such wasteful
burdens upon the States and the Administrator.'' Id. CAA sections
111(d) and 110 are structurally similar in that both require the EPA to
establish targets to meet the objectives of the respective sections
(i.e., the degree of emission limitation set by an EG under CAA section
111(d), and attainment and maintenance of the NAAQS under CAA section
110), and states must adopt and submit to the EPA plans which include
requirements to meet these targets. Specifically, the EPA establishes a
presumptive standard of performance corresponding to the degree of
emission limitation it has determined in an EG, and state plans under
CAA section 111(d) must establish standards of performance that
generally reflect this degree of emission limitation. Because CAA
section 116 applies to ``any standard or limitation,'' this provision
clearly applies to standards of performance adopted under CAA section
111(d). Therefore, the Court's rationale in Union Electric as it
pertains to the application of CAA section 116 in the context of the
cooperative federalism structure of CAA section 110 also applies to CAA
section 111(d). That is, the assessment of CAA section 116 in the
context of requirements that states develop and submit to the EPA for
evaluation against nationally applicable standards or criteria applies
equally to CAA sections 110 and 111(d). On that basis, the EPA is
finding that the Court's holding applies and controls the outcome here,
as well. Requiring states to enact and enforce two sets of standards of
performance, one that is exactly equal to the EPA's presumptive
standard of performance that is federally approved as part of the CAA
section 111(d) plan and one that is stricter and is only adopted and
enforced as a matter state requirements, runs directly afoul of Union
Electric's holding that there is no basis for interpreting CAA section
116 in such manner.
    Moreover, there is nothing in CAA section 111(d) that precludes
states from adopting, and EPA from approving, more stringent standards
of performance.\149\ In fact, permitting

states to adopt more stringent standards of performance and include
such standards in their state plans is entirely consistent with the
purpose and structure of CAA section 111(d). States bear the obligation
pursuant to CAA section 111(d)(1) to establish standards of
performance. Nothing in CAA section 111(d) suggests that Congress
intended to preclude states from determining that it is appropriate to
regulate certain sources within their jurisdiction more strictly than
otherwise required by Federal requirements. For the EPA to do so would
be arbitrary and capricious in light of the overarching purpose of CAA
section 111(d), which is to require emission reductions from existing
sources for certain pollutants that endanger public health or welfare.
It is inconsistent with the purpose of CAA section 111(d) and the role
it confers upon states for the EPA to constrain them from further
reducing emissions that harm their citizens, and the EPA does not see a
reasonable basis for doing so.
---------------------------------------------------------------------------

    \149\ In the 1975 CAA section 111(d) implementing regulations
the Agency explained that EPA's emission guidelines will reflect its
judgment of the degree of control that can be attained by various
classes of existing source without unreasonable costs. Particular
sources within a class may be able to achieve greater control
without unreasonable costs. Moreover, States that believe additional
control is necessary or desirable will be free under section 116 of
the Act to require more expensive controls, which might have the
effect of closing otherwise marginal facilities, or to ban
particular categories of sources outright. 40 FR 53343. Congress did
nothing to disturb the understanding that states can use CAA section
116 to adopt more stringent standards of performance when it enacted
the 1977 CAA Amendments shortly thereafter.
---------------------------------------------------------------------------

    The EPA also included a second rationale for permitting more
stringent standards of performance in the notice of proposed
rulemaking. The Agency explained that CAA section 111(d)(1) provides
that states are permitted to consider remaining useful life and other
factors ``in applying a standard of performance to any particular
source under a plan,'' but does not specify that the source-specific
standard must be a less stringent standard of performance. Aside from
the explicit reference to remaining useful life, the statute is silent
as to what the ``other factors'' are that states may consider in
applying a standard of performance and whether such factors can be used
only to weaken the stringency of a standard of performance for a
particular designated facility. Therefore, in addition to proposing
that states may include, and the EPA must approve, more stringent
standards of performance in state plans pursuant to CAA sections 111(d)
and 116, the EPA also proposed to interpret CAA section 111(d)(1) as
allowing states to consider ``other factors'' in exercising their
discretion to apply a more stringent standard to a particular source.
The Agency acknowledged that it had previously, in promulgating subpart
Ba in 2019, taken the position that the statutory RULOF provision
authorizes only standards of performance that are less stringent than
the presumptive level of stringency required by a particular EG,\150\
and explained why it was proposing to change course. To codify its
revised interpretation of the RULOF provision, the EPA proposed
explicit regulatory text that would have allowed states to use RULOF,
and specifically, ``other factors,'' to apply a more stringent standard
of performance. The new provision at 40 CFR 60.24a(m) would have also
required that state plans include an adequate demonstration that the
standard of performance is more stringent than required by an
application EG and meet all other applicable requirements.
---------------------------------------------------------------------------

    \150\ See EPA's Responses to Public Comments on the EPA's
Proposed Revisions to Emission Guideline Implementing Regulations at
56 (Docket ID No. EPA-HQ-OAR-2017-0355-26740) (July 8, 2019).
---------------------------------------------------------------------------

    The EPA received comments both in support of and opposed to its
proposed interpretation that states may apply more stringent standards
of performance and that EPA has an obligation to approve such standards
in state plans. Several commenters stated the Agency has appropriately
interpreted CAA section 116 and 111(d), as well as Union Electric Co.
v. EPA, as allowing states to submit, and the EPA to approve, more
stringent standards. One commenter also agreed that the statutory
phrase ``remaining useful life and other factors'' does not foreclose a
state plan from applying a more stringent standard of performance to a
particular source; while ``remaining useful life'' implies a less
stringent standard, ``other factors'' does not. Another commenter
asserted that the EPA need not rely on ``other factors'' to permit
states to apply more stringent standards because states already have
the ability to do so in light of the Supreme Court's ruling in Union
Electric. Commenters that disagreed with the EPA's proposed
interpretation generally recognized that states can adopt more
stringent rules than those required by the EPA but asserted that the
CAA does not authorize the EPA to approve them into state plans and
thus make them federally enforceable. One commenter argued that the
EPA's BSER determination defines the extent of both EPA and state
authority under CAA section 111 and that the RULOF provision does not
authorize states to select a different, more stringent BSER under the
guise of RULOF. Another commenter stated that the EPA's position that
RULOF is a variance provision for sources that cannot meet the BSER due
to limited remaining useful life or other factors is in tension with
its interpretation that the same provision provides a broad grant of
authority for states to impose more stringent standards on sources. The
same commenter pointed out the difference in proposed requirements for
states invoking RULOF to apply a less stringent standard and those for
applying a more stringent standard.
    The EPA agrees with commenters that it need not rely on ``other
factors'' for authority to permit states to submit, and the EPA to
approve, more stringent standards of performance in state plans. As
explained above, CAA sections 116 and 111(d), and the Court's
interpretation in Union Electric of section 116 as it relates to CAA
section 110's analogous statutory framework, provide a sufficient basis
this position. Moreover, upon further consideration of the history of
the RULOF provision and the EPA's interpretation of that provision as a
variance for states to use when a source cannot reasonably achieve the
degree of emission limitation determined by the EPA, the Agency is not
finalizing its proposed interpretation that the RULOF provision allows
states to adopt more stringent standards of performance in their plans.
The EPA is therefore not finalizing the provision it proposed at 40 CFR
60.24a(m) that would have explicitly allowed a state to ``account for
other factors in applying a standard of performance that is more
stringent than required by an applicable emission guideline, or the
proposed provision that ``[t]he plan must include an adequate
demonstration that the standard of performance is more stringent than
required by an applicable emission guideline, and must meet all other
applicable requirements, such as those that provide for the
implementation and enforceable of the more stringent standard of
performance.'' As a general matter, states already bear the burden of
demonstrating that their standards of performance are no less stringent
than the corresponding EG. See 40 CFR 60.24a(c).
    The EPA disagrees with comments suggesting that the EPA's BSER
determination is the ceiling--that the EPA is constrained from
approving more stringent standards of performance into state plans. As
explained above, there is no support for this position in the statutory
language or structure of CAA section 111(d). It is also inconsistent
with CAA section 116 and would run counter to the purpose of section
111--reducing emissions of dangerous air pollutants from designated
facilities.

    The EPA anticipates that, in many cases, more stringent standards
of performance would entail marginal differences in stringency between
the degree of emission limitation in the applicable EG and the state
plan requirement. For example, the EPA may determine that, for the
source category in general, a control technology can reasonably achieve
an 80% reduction in emissions, while a state finds that at a particular
designated facility, that same control technology can reasonably
achieve a 90% reduction. Or a state may decide that a particular
designated facility can install a control technology that has already
been demonstrated to reasonably achieve greater emission reductions
than the BSER the EPA determined for the source category generally. The
EPA also notes that approving more stringent standards of performance
in state plans is not a new practice under subpart Ba; for example, in
2020 the EPA approved more stringent standards of performance that
California submitted as part of its CAA section 111(d) state plan to
implement the emission guidelines for landfill gas emissions from
municipal solid waste landfills. These more stringent standards of
performance were incorporated into the Code of Federal Regulations and
thus became federally enforceable.\151\
---------------------------------------------------------------------------

    \151\ 40 CFR 62.1100(b)(7); 85 FR 1121 (Jan. 9, 2020); see also
``Appendix E: Comparison of the Major Provisions of the Emission
Guidelines and California's Landfill Methane Regulation,'' EPA-R09-
OAR-2019-0393-0008 (technical support document for EPA action on
California's CAA section 111(d) state plan to implement the EG for
landfill gas from municipal solid waste landfills).
---------------------------------------------------------------------------

    In summary, the EPA is finalizing, at 40 CFR 60.24a(i), the
proposed revisions to the existing provision (currently at 40 CFR
60.24a(f)) stating that nothing in subpart Ba shall be construed to
preclude any state from adopting or enforcing, as part of a state plan,
(1) standards of performance more stringent that the applicable EG, or
(2) compliance schedules requiring final compliance at earlier times
than specified in the applicable EG. The EPA is not finalizing the
regulatory text provision proposed at 40 CFR 60.24a(m) stating that a
state may account for other factors in applying a more stringent
standard of performance.

F. Provision for Electronic Submission of State Plans

    The EPA proposed to revise subpart Ba to require electronic
submission of state plans instead of paper copies.\152\ As explained in
the notice of proposed rulemaking, the regulations promulgated in 2019
require state plan submissions to be made in accordance with 40 CFR
60.4. Pursuant to 40 CFR 60.4(a), all requests, reports, applications,
submittals, and other communications to the Administrator pursuant to
40 CFR part 60 shall be submitted in duplicate to the appropriate
regional office of the EPA. The provision in 40 CFR 60.4(a) then
proceeds to list the corresponding addresses for each regional office.
The EPA proposed that, rather than requiring paper copies of state plan
submissions to be sent to the appropriate regional office, states would
submit their state plans electronically via the use of its State
Planning Electronic Collaboration System (SPeCS).
---------------------------------------------------------------------------

    \152\ 87 FR 79206.
---------------------------------------------------------------------------

    As previously described, CAA section 111(d) requires the EPA to
promulgate a ``procedure'' similar to that of CAA section 110 under
which states submit plans. The statute does not prescribe a specific
platform for plan submissions, and the EPA reasonably interprets the
procedure it must promulgate under the statute as allowing it to
require electronic submission. Requiring electronic submission is
reasonable for the following reasons. Providing for electronic
submittal of CAA section 111(d) state plans in subpart Ba in place of
paper submittals aligns with current trends in electronic data
management and as implemented in the individual EGs will result in less
burden on the states. It is the EPA's experience that the electronic
submittal of information increases the ease and efficiency of data
submittal and data accessibility. The EPA's experience with the
electronic submittal process for SIPs under CAA section 110 has been
successful as all the states are now using the SPeCS, which is a user-
friendly, web-based system that enables state air agencies to
officially submit SIPs and associated information electronically for
review and approval to meet their CAA obligations related to attaining
and maintaining the NAAQS. SPeCS for SIPs is the EPA's preferred method
for receiving such SIPs submissions. The EPA has worked extensively
with state air agency representatives and partnered with E-Enterprise
for the Environment and the Environmental Council of the States to
develop this integrated electronic submission, review, and tracking
system for SIPs. SPeCS can be accessed by the states through the EPA's
Central Data Exchange (CDX) (https://cdx.epa.gov/). The CDX is the
Agency's electronic reporting site and performs functions for receiving
acceptable data in various formats. The CDX registration site supports
the requirements and procedures set forth under the EPA's Cross-Media
Electronic Reporting Regulation, 40 CFR part 3.
    Most of the commenters were supportive of the proposed amendments
for electronically submitting state plans. However, a few commenters
expressed that EPA should provide an option to submit state plans in
paper format. The EPA has determined that submitting state plans
electronically is more efficient and less burdensome than paper
submittals. States already submit state implementation plans
electronically via SPeCS so there should be little to no additional
burden associated with using it for state plans. Additionally, having
some states submit state plans via SPeCS and other states mail hard-
copy plans to regional offices would undermine many of the efficiencies
provided to the EPA through the use of electronic submission and could
result in confusion. One commenter recommended adding language to
clarify that a Negative Declaration letter submitted in accordance with
40 CFR 60.23a(b) can also be submitted via SPeCS. The EPA agrees with
the need to add the electronic submittal language to 40 CFR 60.23a(b)
identified by the commenter and has added the language in the final
rule so that the states submit the Negative Declaration letter using
the SPeCS, or through an analogous electronic reporting tool provided
by the EPA for the submission of any plan required by this subpart.
    The EPA is therefore finalizing the requirements for electronic
submittal of state plans in 40 CFR 60.23a(a)(1) and (3). As finalized,
40 CFR 60.23a(a)(1) provides: ``The submission of such plan shall be
made in electronic format according with Sec.  60.23a(a)(3) or as
specified in an applicable emission guideline.'' The regulation at 40
CFR 60.23a(a)(3) in turn contains the general requirements associated
with the electronic submittal of a state plan in subpart Ba via the use
of SPeCS or through an analogous electronic reporting tool provided by
the EPA for the submission of any plan required by subpart Ba. The EPA
is also including at 40 CFR 60.23a(a)(3) language to specify that
states are not to transmit confidential business information (CBI)
through SPeCS. Even though state plans submitted to the EPA for review
and approval pursuant to CAA section 111(d) through SPeCS are not to
contain CBI, the language at 40 CFR 60.23a(a)(3) also addresses the
submittal of CBI in the event there is a need for such information to
be submitted to the EPA.

    Any other specific requirements associated with the electronic
submittal of a particular state plan will be provided within the
corresponding EG. The requirements for electronic submission of CAA
section 111(d) state plans in EGs will ensure that these Federal
records are created, retained, and maintained in electronic format.
Electronic submittal will also improve the Agency's efficiency and
effectiveness in the receipt and review of state plans. The electronic
submittal of state plans may also provide continuity in the event of a
disaster like the one our nation experienced with COVID-19.

G. Other Proposed Modifications and Clarifications

1. Standard of Performance and Compliance Flexibility
a. Definition of Standard of Performance
    The EPA proposed amendments to 40 CFR 60.21a(f) and 60.24a(b) to
clarify that the definition of ``standard of performance'' allows for
state plans to include standards in the form of an allowable mass limit
of emissions. As explained in the notice of proposed rulemaking,\153\
the amendments were intended to harmonize these regulatory definitions
with the definitions of ``emission limitation'' and ``emission
standard'' in CAA section 302(k), which is ``a requirement established
by the State or the Administrator which limits the quantity, rate, or
concentration of emissions of air pollutants on a continuous basis,
including any requirement relating to the operation or maintenance of a
source to assure continuous emission reduction, and any design,
equipment, work practice, or operational standard promulgated under
this chapter.'' While the EPA had intended the phrase ``allowable rate
or limit of emissions'' in the existing regulatory definitions to
encompass the full range of forms included in the statute, to eliminate
any potential confusion the Agency proposed to make this explicit.
---------------------------------------------------------------------------

    \153\ 87 FR 79176, 79206-07 (Dec. 23, 2022).
---------------------------------------------------------------------------

    Most comments received on the proposed revision to the definition
of ``standard of performance'' were in support of these amendments.
Some commenters pointed out that the revision would be consistent with
the statutory definition in CAA section 302(k) and many expressed
approval that the revised definition would clearly allow for standards
of performance to take the form of mass-based emission limits. Several
commenters stressed that, while they supported the proposed definition
of standard of performance for subpart Ba, the appropriate form of the
standard of performance in any particular EG must be determined in the
context of that EG. Some commenters expressed concern that the proposed
revision would allow the EPA to define the BSER as a trading program
for any source sector, or for states and the EPA to impose emissions
averaging and trading programs in CAA section 111(d) plans.
    The EPA is finalizing amendments to 40 CFR 60.21a(f) and 60.24a(b)
as proposed. The Agency's interpretation of CAA section 111 with regard
to emissions trading or averaging is a separate matter that is
discussed in section III.G.1.b. of this preamble; it is reiterated that
the revisions to the definition of standard of performance are being
made to align it with the statutory definition of emission limitation
and emission standard in CAA section 302(k) for the purpose of these
general implementing regulations. The EPA agrees with commenters that
the appropriate form of the standard of performance in any particular
EG must be determined in the context of that EG, and the EPA may choose
to prescribe the acceptable form or forms of the standard of
performance in an individual EG. In addition to finalizing the proposed
amendments to 40 CFR 60.21a(f) to clarify that the term ``an allowable
rate or limit of emissions'' means ``an allowable rate, quantity, or
concentration of emissions'' of air pollutants, the EPA is also
finalizing its proposed removal of the phrase ``but not limited to''
from 40 CFR 60.21a(f) as unnecessary and potentially confusing verbiage
that is redundant of the word ``including,'' particularly where the
definition already identifies a wide breadth of potential standards
that may be included in a state plan. Moreover, the EPA is finalizing
amendments to the definition of standard of performance under 40 CFR
60.24a(b) to read ``. . . in the form of an allowable rate, quantity,
or concentration of emissions'' rather than ``. . . either be based on
allowable rate or limit of emission.''
b. Compliance Flexibilities, Including Trading or Averaging
    The EPA is finalizing its proposal that CAA section 111(a) and (d)
cannot be interpreted, by their terms, to limit the types of controls
that states, in their state plans, may authorize their sources to adopt
to at-the-source, and thereby preclude states from authorizing their
sources flexibilities such as trading or averaging. Under the
provisions of CAA section 111(a) and (d), and consistent with the
federalism principles that underlie the CAA, states have broad
authority to determine the types of control measures for their sources,
including trading or averaging, although the EPA may establish
constraints to protect the integrity of particular EGs. The EPA is also
finalizing its proposal that CAA section 111 cannot be interpreted, by
its terms, to limit the ``best system of emission reduction . . .
adequately demonstrated'' (BSER) to at-the-source measures. As the EPA
explains, many control measures that the EPA has determined to be the
BSER in prior rules have outside-the-source components. The EPA is
finalizing its repeal of the ACE Rule's contrary interpretations of CAA
section 111.
    In the proposal, the EPA provided a brief summary of the applicable
CAA provisions, the ACE Rule, the D.C. Circuit's decision reversing the
ACE Rule, and the U.S. Supreme Court's decision vacating the D.C.
Circuit's vacatur of the ACE Rule.\154\ For convenience, parts of that
summary are reproduced here.
---------------------------------------------------------------------------

    \154\ 87 FR 79176, 79207-08 (Dec. 23, 2022).
---------------------------------------------------------------------------

    i. CAA section 111. Under CAA section 111(d)(1), each state is
required to submit to the EPA ``a plan which . . . establishes
standards of performance for any existing source'' that emits certain
types of air pollutants, and which ``provides for the implementation
and enforcement of such standards of performance.'' Under CAA section
111(a)(1), a ``standard of performance'' is defined as ``a standard for
emissions of air pollutants which reflects the degree of emission
limitation achievable through the application of the best system of
emission reduction . . . adequately demonstrated.''
    ii. Rulemaking and caselaw. In the Clean Power Plan (CPP), the EPA
interpreted the term ``system'' in CAA section 111(a)(1) to be broad
and therefore to authorize the EPA to consider a wide range of measures
from which to select the BSER.\155\ Similarly, the CPP took the
position that states had broad flexibility in choosing compliance
measures for their state plans.\156\ The CPP went on to determine that
generation shifting qualified as the BSER,\157\ and that states could
include trading or averaging programs in their state plans for
compliance.\158\
---------------------------------------------------------------------------

    \155\ 80 FR 64662, 64720 (October 23, 2015).
    \156\ See, e.g., id. at 64887.
    \157\ Id. at 64707.
    \158\ Id. at 64840.
---------------------------------------------------------------------------

    The ACE Rule included the repeal of the CPP. It interpreted CAA
section 111 so that the type of ``system'' that the EPA may select as
the BSER is limited to a control measure that could be

applied at each source (that is, inside the fenceline of each source)
to reduce emissions at each source.\159\ The ACE Rule also concluded
that the compliance measures the states include in their plans must
``correspond with the approach used to set the standard in the first
place,'' \160\ and therefore must also be limited to inside-the-
fenceline measures that reduce the emissions of each source. For these
reasons, the ACE Rule invalidated the CPP's generation-shifting system
as the BSER, on grounds that it was an outside the source measure, and
precluded states from allowing their sources to trade or average to
demonstrate compliance with their emission standards.\161\
---------------------------------------------------------------------------

    \159\ 84 FR 32520, 32523-24 (July 8, 2019).
    \160\ Id. at 32556.
    \161\ Id. at 32556-57.
---------------------------------------------------------------------------

    In 2021, the D.C. Circuit vacated the ACE Rule.\162\ The court
held, among other things, that CAA section 111(d) does not limit the
EPA, in determining the BSER, to at-the- source measures.\163\ The
court further held that the ACE Rule's premise for viewing compliance
measures as limited to at the source measures, which is that BSER
measures are so limited, was invalid for the same reason. The court
indicated that while requiring symmetry between the nature of the BSER
and compliance measures ``would be reasonable'' where necessary to
preserve the environmental outcomes a particular BSER was designed to
achieve, a universal restriction on compliance measures could not be
sustained by policy concerns that were not similarly universal.\164\
---------------------------------------------------------------------------

    \162\ American Lung Ass'n v. EPA, 985 F.3d 914 (D.C. Cir. 2021).
    \163\ Id. at 944-51
    \164\ Id. at 957-58.
---------------------------------------------------------------------------

    In 2022, the U.S. Supreme Court reversed the D.C. Circuit's vacatur
of the ACE Rule's embedded repeal of the Clean Power Plan.\165\ The
Supreme Court made clear that CAA section 111 authorizes the EPA to
determine the BSER and the amount of emission limitation that state
plans must achieve.\166\ However, the Supreme Court invalidated the
CPP's generation-shifting BSER under the major question doctrine,
explaining that the term ``system'' does not provide the ``clear
congressional authorization'' needed to support a BSER ``of such
magnitude and consequence.'' \167\ The Court declined to address the
D.C. Circuit's decision that the text of CAA section 111 did not limit
the type of ``system'' the EPA could consider as the BSER to at-the-
source measures.\168\ Nor did the Court rule on the scope of the
states' compliance flexibilities.
---------------------------------------------------------------------------

    \165\ West Virginia v. EPA, 142 S. Ct. 2587 (2022).
    \166\ Id. at 2601-02.
    \167\ Id. at 2614-16 (internal quotation marks omitted).
    \168\ See id. at 2615 (``We have no occasion to decide whether
the statutory phrase `system of emission reduction' refers
exclusively to measures that improve the pollution performance of
individual sources, such that all other actions are ineligible to
qualify as the BSER.'' (emphasis omitted)).
---------------------------------------------------------------------------

    iii. Proposal. In the proposal, the EPA stated that it has
reconsidered the ACE Rule's interpretation of the compliance
flexibilities available to states under CAA section 111 and that it was
proposing to disagree with the rule's view that trading or averaging
are universally precluded \169\ and that state plan compliance measures
must always correspond with the approach the EPA uses to set the BSER.
The EPA added, however, that the flexibility that CAA section 111(d)
grants to states in adopting measures for their state plans is not
unfettered; rather, CAA section 111(d)(2) requires the EPA to review
state plans to ensure that they are ``satisfactory,'' and the EPA may
conclude in particular emission guidelines that limiting the types of
control measures states may authorize their sources to adopt, including
precluding trading or averaging, are necessary to protect the
environmental outcomes of the emission guidelines.\170\
---------------------------------------------------------------------------

    \169\ With respect to averaging, the ACE Rule noted that the
D.C. Circuit has recognized that the EPA may have statutory
authority under CAA section 111 to allow plant-wide emissions
averaging, See U.S. Sugar v. EPA, 830 F.3d 579, 627 n.18 (D.C. Cir.
2016) (pointing to the definition of ``stationary source''), but
stated that the Agency's determination that individual EGUs are
subject to regulation under ACE precludes the Agency from attempting
to change the basic unit from an EGU to a combination of EGUs for
purposes of ACE implementation.
    \170\ 87 FR 79208.
---------------------------------------------------------------------------

    In addition, the EPA also proposed to reject the ACE Rule's
interpretation that various provisions in CAA section 111 limit the
type of ``system'' that may qualify as the BSER to at-the-source
measures.\171\ The EPA explained that it proposed to agree with the
part of the D.C. Circuit's decision in American Lung Ass'n,\172\ that
rejected the ACE Rule's at-the-source statutory interpretation. The EPA
added that it recognized that the Supreme Court, in West Virginia, did
impose limits, through the application of the major question doctrine,
on the type of ``system'' that may qualify as the BSER.\173\ The EPA
made clear that it was not proposing to address the scope of the limits
that may result from application of the major question doctrine, and
thus was not proposing to address whether it could include trading or
averaging as part of the BSER, or to identify any particular control
mechanism that could or could not be part of a specific BSER, in light
of those limits. Instead, the EPA stated that it may address further
those limits, and their implications for the legality of particular
systems of emission reduction and state compliance measures, in future
emission guidelines.\174\
---------------------------------------------------------------------------

    \171\ 84 FR 32556.
    \172\ 985 F.3d at 944-51.
    \173\ 142 S. Ct. at 2615-16.
    \174\ 87 FR 79208.
---------------------------------------------------------------------------

    iv. The EPA's finalized interpretation of state authority to grant
compliance flexibilities. The EPA is finalizing its proposal that,
contrary to the position of the ACE Rule, CAA section 111 does not
preclude states from including compliance flexibilities such as trading
or averaging for their sources in their state plans, although in
particular emission guidelines the EPA may limit those flexibilities if
necessary to protect the environmental outcomes of the guidelines. The
EPA is also rescinding the related ACE Rule interpretation that CAA
section 111 requires that state plan measures be symmetrical to the
types of measures the EPA included in the BSER.
    Most commenters agreed with the proposal that CAA section 111 does
not preclude states from including compliance flexibilities in their
state plans. However, several commenters disagreed and submitted
adverse comments. Some commenters stated that West Virginia is clear
that the EPA cannot include generation-shifting as the BSER, and then
argued that the EPA cannot include trading as part of the BSER because
trading entails generation shifting, and then further argued that for
emission guidelines applicable to electric generating units, the EPA
cannot authorize trading as a compliance mechanism because trading
incentivizes generation shifting to occur and only works if generation
shifting does occur. As explained further below, the EPA does not
believe that these adverse comments cast doubt on the rationale that it
gave in the proposal for why states have the authority to allow
compliance flexibilities such as trading or averaging.\175\ The EPA
continues to agree with the reasoning in American Lung Ass'n,\176\ in
rejecting the ACE Rule's limitations on those measures.
---------------------------------------------------------------------------

    \175\ Id.
    \176\ 985 F.3d at 957-58.
---------------------------------------------------------------------------

    To review the reasons that the ACE Rule gave for asserting that
trading or averaging across designated facilities is inconsistent with
CAA section 111: The ACE Rule stated that those options would not
necessarily require any emission reductions from designated

facilities and may not actually reflect application of the BSER. The
ACE Rule explained that ``state plans must establish standards of
performance--which by definition `reflects . . . the application of the
best system of emission reduction,' '' \177\ and then asserted that
implementation and enforcement of such standards should be based on
improving the emissions performance of sources to which a standard of
performance applies. The ACE Rule added that trading or averaging would
effectively allow a state to establish standards of performance that do
not reflect application of the BSER, and gave, as an example, the
possibility that under a trading program, a single source could
potentially shut down or reduce utilization to such an extent that its
reduced or eliminated operation generates sufficient allowances for a
state's remaining sources to meet their standards of performance
without themselves making any emission reductions from any other
source. The ACE Rule asserted that this compliance strategy would
undermine the EPA's determination of the BSER.\178\
---------------------------------------------------------------------------

    \177\ This paraphrasing by the ACE Rule of the CAA section
111(a)(1) definition of ``standard of performance'' is incomplete--a
``standard of performance'' ``reflects the degree of emission
limitation achievable through the application of the best system of
emission reduction.''
    \178\ 84 FR 32557.
---------------------------------------------------------------------------

    This interpretation of CAA section 111 is unduly strained and the
EPA rejects it. The provisions of CAA section 111(d) by their terms do
not affirmatively bar states from considering trading or averaging as a
compliance measure where appropriate for a particular emission
guideline. Under CAA section 111(d)(1), each state must ``establish[
],'' ``implement[ ],'' and ``enforce[ ]'' ``standards of performance
for any existing source.'' A state plan may ``establish[ ]'' a standard
of performance for each source that constitutes an emissions standard
that reflects the amount of emission reduction that the source could
achieve by applying the BSER, but the state may also allow measures
like trading or averaging as potential means of compliance. Nothing in
the text of CAA section 111 precludes states from considering a
source's acquisition of allowances as part of a trading program in
``implement[ing]'' and ``enforce[ing]'' a standard of performance for
that particular source, so long as the state plan achieves the required
overall level of emission reductions.\179\ CAA section 111(d)(1)
requires only that each source comply with its standard, not that each
source do so through applying the BSER. By the same token, contrary to
the ACE Rule,\180\ CAA section 111(d)(1) does not limit the states to
compliance measures that are symmetrical to what the EPA determined to
be the BSER unless necessary to preserve the environmental outcomes a
particular system was designed to achieve.
---------------------------------------------------------------------------

    \179\ This overall level of emissions reduction is the level
that would be achieved if each source were to apply the BSER.
    \180\ 84 FR 32556 (ACE Rule states that one reason why CAA
section 111 precludes states from authorizing trading or averaging
is that ``[a]pplying an implementation approach that differs from
standard-setting would result in asymmetrical regulation'').
---------------------------------------------------------------------------

    For further support for the interpretation that CAA section 111
does not preclude states from authorizing compliance flexibilities such
as trading or averaging, the EPA notes that CAA section 111(d)(1)
requires a ``procedure similar to that provided by [CAA section 110].''
\181\ Consideration of the CAA section 110 framework reinforces the
absence of any mandate that states consider only compliance measures
that apply at and to an individual source. ``States have `wide
discretion' in formulating their plans'' under section 110.\182\ The
EPA has authorized trading programs in CAA section 110 SIPs for
decades. See Economic Incentive guidance.\183\
---------------------------------------------------------------------------

    \181\ See CAA section 111(d)(2)(A) (referring to CAA section
110(c)), 111(d)(2)(B) (referring to enforcement of state
implementation plans (SIPs)).
    \182\ Alaska Dep't of Envtl. Conservation v. EPA, 540 U.S. 461,
470 (2004) (citation omitted); see Union Elec. Co. v. EPA, 427 U.S.
246, 269 (1976) (``Congress plainly left with the States, so long as
the national standards were met, the power to determine which
sources would be burdened by regulation and to what extent.'');
Train v. Natural Res. Def. Council, Inc., 421 U.S. 60, 79 (1975)
(``[S]o long as the ultimate effect of a State's choice of emission
limitations is compliance with the national standards for ambient
air, the State is at liberty to adopt whatever mix of emission
limitations it deems best suited to its particular situation.'').
    \183\ The ACE Rule stated that the reference in CAA section
111(d)(1) to CAA section 110 was limited to the procedure under
which states shall submit plans to the EPA, and asserted that it
does not imply anything about implementation mechanisms available
under CAA section 111(d). 84 FR 32557. The EPA believes that the
several references to CAA section 110 in CAA section 111(d)(1) and
(2), as noted in the accompanying text, support the view that
Congress intended that state plans under CAA section 111(d) would be
similar to state plans under CAA section 110, including retaining
the authority to grant sources compliance flexibility in appropriate
circumstances.
---------------------------------------------------------------------------

    Such flexibility is consistent with the framework of cooperative
federalism that CAA section 111(d) establishes, which vests states with
substantial discretion in establishing control requirements for their
sources. As the U.S. Supreme Court has explained, CAA section 111(d)
``envisions extensive cooperation between Federal and state
authorities, generally permitting each State to take the first cut at
determining how best to achieve EPA emissions standards within its
domain.'' \184\
---------------------------------------------------------------------------

    \184\ American Elec. Power Co. v. Connecticut, 564 U.S. 410, 428
(2011) (citations omitted).
---------------------------------------------------------------------------

    This interpretation is also consistent with the EPA's consistent
views prior to the ACE Rule. The EPA authorized trading or averaging as
compliance methods in the 2005 Clean Air Mercury Rule for coal-fired
EGUs,\185\ and the 2015 Clean Power Plan (CPP).\186\
---------------------------------------------------------------------------

    \185\ 70 FR 28606, 28617 (May 18, 2005), vacated on other
grounds, New Jersey v. EPA, 517 F.3d 574 (D.C. Cir. 2008), see 40
CFR 60.24(b)(1) (2005) (providing that a state's ``[e]mission
standards [may] be based on an allowance system), repealed in the
ACE Rule.
    \186\ 80 FR 64662, 64840 (October 23, 2015), repealed by the ACE
Rule. 87 FR 79208.
---------------------------------------------------------------------------

    It must be emphasized that the EPA retains an important role in
reviewing state plans for adequacy. Under CAA section 111(d)(2)(A), the
EPA must determine that the state plan is ``satisfactory'' and, if the
state plan is not satisfactory or if the state does not submit a state
plan, the EPA must promulgate a plan that establishes Federal standards
of performance for the State's existing sources. Thus, the flexibility
that CAA section 111(d)(1) grants to states in adopting measures for
their state plans is not unfettered. As the Supreme Court stated in
West Virginia, ``The Agency, not the States, decides the amount of
pollution reduction that must ultimately be achieved.'' \187\ The Court
further stated that state plans must contain ``emissions restrictions
that they intend to adopt and enforce in order not to exceed the
permissible level of pollution established by EPA.'' \188\ Thus, the
EPA retains the authority to ensure that the permissible level of
pollution is not exceeded by any state plan. If the EPA considers that
compliance flexibility measures would compromise the ability of the
state plan to achieve the environmental outcomes the best system could
achieve, the EPA may, in the emission guidelines, preclude such
measures or otherwise conclude that the state plan is not satisfactory.
---------------------------------------------------------------------------

    \187\ 142 S. Ct. at 2602.
    \188\ Id.
---------------------------------------------------------------------------

    In West Virginia v. EPA, the Supreme Court did not directly address
the state's authority to determine their sources' control measures.
Although the Court did hold that constraints apply to the EPA's
authority in determining the BSER, the Court's discussion of CAA
section 111 is consistent with the EPA's interpretation that the
provision does not preclude states from granting sources compliance
flexibility.
    At the outset of the decision, the Court made clear CAA section 111

provides different roles for the EPA and the States:

    Although the States set the actual rules governing existing
power plants, EPA itself still retains the primary regulatory role
in Section 111(d). The Agency, not the States, decides the amount of
pollution reduction that must ultimately be achieved. It does so by
again determining, as when setting the new source rules, ``the
[BSER]. . . . The States then submit plans containing the emissions
restrictions that they intend to adopt and enforce in order not to
exceed the permissible level of pollution established by EPA.\189\
---------------------------------------------------------------------------

    \189\ West Virginia v. EPA, 142 S.Ct. at 2601-02 (citations
omitted).

    The Court was clear that the focus of the case was exclusively on
the EPA's role, that is, whether the EPA acted within the scope of its
authority in establishing the BSER.\190\ The Court applied the major
question doctrine to hold that the generation-shifting BSER that the
EPA promulgated in the CPP exceeded the constraints of the CAA section
111 BSER provisions, in light of ``separation of powers principles and
a practical understanding of legislative intent.'' \191\ The Court did
not identify any constraints on the states in establishing standards of
performance to their sources, and its holding and reasoning cannot be
extended to apply such constraints. In fact, the Supreme Court at least
implicitly recognized that CAA section 111(d) does not preclude states
from authorizing sources compliance flexibility when the Court observed
that a new or modified source ``may achieve [the EPA-determined]
emissions [standard] any way it chooses.'' \192\ There is no reason why
existing sources should have less flexibility.
---------------------------------------------------------------------------

    \190\ Id. at 2600 (``The question before us is whether this
broad[ ] conception of EPA's authority [to determine the BSER] is
within the power granted to it by the Clean Air Act.'').
    \191\ Id. at 2609.
    \192\ Id. at 2601.
---------------------------------------------------------------------------

    It should also be noted that the adverse commenters described above
are incorrect in their view that trading necessarily results in
generation shifting and that the logic of the West Virginia decision
precludes any such generation shifting. As just noted, the reasons why
the Court held that the CPP's generation-shifting BSER violated the
major question doctrine and thus was invalid have no application to
states in developing state plans. In addition, the Court was clear that
a BSER that has the incidental effect of resulting in generation
shifting would not, on those grounds, violate the major question
doctrine. The Court emphasized that ``there is an obvious difference
between (1) issuing a rule that may end up causing an incidental loss
of coal's market share, and (2) simply announcing what the market share
of coal, natural gas, wind, and solar must be, and then requiring
plants to reduce operations or subsidize their competitors to get
there.'' \193\ The second option is what the Court viewed the CPP's
generation-shifting BSER as attempting to do, which thereby triggers
the major question doctrine. But, as a coalition of companies that
operate electricity generation as well as transmission and distribution
systems commented, the Court ``evinced no general concern about option
1, which is an inevitable consequence of regulation within the power
sector, in which all sources of emissions are interconnected and
increase or decrease their generation based upon demand for electricity
and other sources' availability.'' \194\ If the Court in West Virginia
had little concern with the EPA determining a BSER that has the
incidental effect of shifting generation, there is no basis for reading
the case to preclude a state from adopting trading measures in its
state plan on grounds that those measures may have the incidental
effect of shifting generation. In any event, in many instances, trading
simply apportions the cost of controls between the sources engaged in
the transaction, and does not result in generation shifting. To
illustrate, assume that the EPA promulgates an emissions guideline that
determines as the BSER the installation by a source of control
equipment that captures 40 percent of its emissions of a pollutant.
Assume further that a state allows two of its designated facilities of
comparable size and emissions to engage in an emission trade, so that
one source installs control equipment that captures 80 percent of its
emissions, and the other one does not put on control equipment but
purchases allowances from the first one that fund half the costs of the
first one's control equipment. This type of emissions trade would not
necessarily give rise to generation shifting.
---------------------------------------------------------------------------

    \193\ Id. at 2613 n.4.
    \194\ Comment Letter from Energy Strategy Coalition on
``Adoption and Submittal of State Plans for Designated Facilities:
Implementing Regulations Under Clean Air Act Section 111(d), EPA-HQ-
OAR-2021-0527-0088 at 6.
---------------------------------------------------------------------------

    For the reasons noted above, the EPA is rescinding the ACE Rule's
interpretation that state plans may not include trading or averaging or
other compliance flexibilities.
    v. The EPA's finalized interpretation of BSER. The EPA is also
finalizing its proposal to rescind the ACE Rule's interpretation that
CAA section 111, by its plain meaning, limits the BSER to at-the-source
measures. The ACE Rule's interpretation is incorrect. In addition, as a
practical matter, it could call into question many of the EPA's
determinations in prior CAA section 111 rules that well-established
control measures, including clean fuels and add-on control technology,
qualified as the BSER. This is because many of these traditional
measures are not entirely at-the-source controls, but also include
outside-the-source components. West Virginia does not preclude the EPA
from rescinding the ACE Rule interpretation because although the
Supreme Court held that the CPP's generation-shifting BSER violated the
major question doctrine, Court declined to address the ACE Rule's
interpretation of CAA section 111.\195\
---------------------------------------------------------------------------

    \195\ 142 S.Ct. at 2615-16.
---------------------------------------------------------------------------

    To repeat for convenience the key requirements for determining the
BSER under CAA section 111: each state must establish ``standards of
performance for any existing source'' of certain types of air
pollutants, under CAA section 111(d)(1); a ``standard of performance''
is defined as ``a standard for emissions of air pollutants which
reflects the degree of emission limitation achievable through the
application of the best system of emission reduction . . . adequately
demonstrated, under CAA section 111(a)(1);'' and ``existing source'' is
defined as a ``stationary source,'' which, in turn, is defined, in
relevant part, as ``any building, structure, facility or
installation,'' under CAA section 111(a)(6) and (a)(3).
    The ACE Rule interpreted CAA section 111 to limit, by its plain
language, the type of ``system'' that the EPA may select as the BSER to
control measures that can be applied at each source to reduce that
source's emissions.\196\ Specifically, the ACE Rule argued that the
requirements in CAA section 111(d)(1), (a)(3), and (a)(6) that each
state establish a standard of performance ``for'' ``any existing
source'' (in the singular), defined, in general, as any ``building . .
. [or] facility,'' and the requirements in CAA section 111(a)(1) that
the standard of performance reflect a degree of emission limitation
that is ``achievable'' through the ``application'' of the BSER, by
their terms, impose this limitation.\197\
---------------------------------------------------------------------------

    \196\ 84 FR 32523-24.
    \197\ Id. at 32556-57.
---------------------------------------------------------------------------

    Upon reconsideration, the EPA concludes that, contrary to the ACE
Rule, CAA section 111(d) does not limit the EPA to at-the-source
measures in determining the BSER. The CAA section

111 requirement that each state establish a standard of performance
``for'' any existing ``building . . . [or] facility,''' means simply
that the state must establish standards applicable to each regulated
stationary source; and the requirement that the standard reflect a
degree of emission limitation ``achievable'' through the
``application'' of the BSER means that the source must be able to apply
the system to meet the standard. None of these requirements by their
plain language mandate that the BSER is limited to some measure that
each source can apply to its own facility to reduce its own emissions
in a specified amount. That the standards must be ``for'' a source does
not mean that the control measures that form the basis for the standard
are limited to measures that apply at the source or that all emission
reductions from the control measures must occur at the source.
    The ACE Rule also argued that as a matter of grammar, the term
``application,'' which is derived from the verb, ``to apply,'' requires
an indirect object, and, further, that the phrase ``application of the
best system of emission reduction'' has, as the unstated indirect
object, an existing source. From this premise, the ACE Rule concluded
that the phrase must be read to refer to the application of the best
system of emission reduction at or to the existing source itself.\198\
But this premise is incorrect. As the D.C. Circuit explained in
American Lung Ass'n, ``application'' is a noun, and ``the phrase
`application of the best system of emission reduction' is what is
called a nominalization, a `result of forming a noun or noun phrase
from a clause or a verb.' '' \199\ The court further explained that
``[g]rammar assigns direct or indirect objects only to verbs--not
nouns. No objects are needed to grammatically complete the actual
statutory phrase.'' \200\ In any event, the fact that any such indirect
object is unstated itself contradicts the ACE Rule's conclusion that
CAA section 111 by its plain language mandates that the BSER must be
limited to at-the-source measures.\201\
---------------------------------------------------------------------------

    \198\ Id. at 32524.
    \199\ 985 F.3d at 948 (citations omitted).
    \200\ Id.
    \201\ The ACE Rule stated that the CAA provisions concerning the
``best available control technology'' (BACT) provide a CAA
structural argument that supports its interpretation that CAA
section 111 limits BSER to at-the-source measures. CAA section
165(a)(4) provides that construction and modification of major
stationary sources of a pollutant are subject to BACT, as defined
under CAA section 169(3), for each pollutant subject to regulation
under the CAA. The definition of BACT provides, ``In no event shall
application of [BACT] result in emissions of any pollutants which
will exceed the emissions allowed by any applicable standard
established pursuant to [CAA] section [111] or [112].'' The ACE Rule
pointed to the EPA's reading of this sentence to mean that section
111 standards of performance ``operate as a floor to BACT.'' The ACE
Rule asserted that, under the definition of BACT, control measures
are limited to at-the-source measures. The ACE Rule reasoned that
section 111 standards of performance must, by operation of the
structure of the CAA, also be interpreted to be limited to at-the-
source measures. 84 FR 32525. Upon further review, the EPA rejects
this argument. The EPA considers whether CAA section 169(3) should
be interpreted to limit BACT to at-the-source measures to be an open
question, and is not addressing it at this time. Even if BACT were
so limited, the ACE Rule did not demonstrate that any BACT
requirement that a particular source would be subject to would be
incompatible with any standard of performance that source would also
be subject to. Section 169(3) by its plain language provides that
the application of BACT may not result in exceedances of any
applicable standard of performance.
    The ACE Rule also focused on statements in the CPP that it
asserted conflated the terms ``application'' and implementation, as
well as ``source'' and owner/operator; and that defined ``system''
broadly. The rule asserted that the CPP strained the interpretation
of CAA section 111 in those ways to justify determining generation-
shifting as the BSER. 84 FR 32526-29. Regardless of whether those
arguments have merit with respect to the generation-shifting, they
are not relevant to the position that the EPA is taking in the
present action that the ACE Rule erred in interpreting CAA section
111 by its terms to limit the BSER to at-the-source measures. It
should also be noted that the CPP's recognition that as a practical
matter, it is the owner/operator who takes actions to apply control
measures and assure that the source's emissions meet the standard is
a matter of common sense and applies as well to all control
measures, whether at the source or outside the source. The ACE Rule
itself referred to the ``owner or operator'' as the entity that
``must be able to achieve an applicable standard by applying the
BSER . . . .'' 84 FR 32524.
---------------------------------------------------------------------------

    It should also be noted that CAA section 111(a)(1) provides that
when the EPA determines the BSER, it must ``tak[e] into account''
``cost'' and ``any nonair quality health and environmental impact and
energy requirements.'' As the ACE Rule itself recognized, the EPA may
consider the application of these requirements on a ``sector-wide,
region-wide or nationwide basis.'' \202\ As discussed below, the
reference to ``nonair quality health and environmental impact'' may
encompass to offsite impacts of control measures. Thus, these
provisions contradict the ACE Rule's argument that CAA section
111(d)(1) and (a), by its plain language, limits the BSER to at-the-
source measures. By the same token, the term ``achievable'' refers to
the ``degree of emission limitation'' that must be ``reflect[ed]'' in
the standards of performance ``through the application of the [BSER].''
This term does not, by its plain language, limit the BSER to at-the-
source measures.
---------------------------------------------------------------------------

    \202\ 84 FR 32534 n.152 (referring to application of ``energy
requirements'').
---------------------------------------------------------------------------

    Importantly, it should be emphasized that the ACE Rule's
interpretation that the provisions of CAA section 111(d)(1) and (a) by
their plain language require that the EPA identify as the BSER control
measures that apply at-the-source would also impose the same limit on
the state, that is, limit the state to authorizing its sources to
comply with their standards only through at-the-source measures. As a
result, this interpretation would preclude the state from allowing its
sources compliance flexibilities such as trading or averaging. In fact,
the ACE Rule argued that states were limited in that manner. For the
reasons noted above, limiting the states in that manner is contrary to
the provisions of CAA section 111(d) and the framework of cooperative
federalism that CAA section 111(d) establishes.
    The ACE Rule also argued that the legislative history of the 1970
CAA Amendments confirms the rule's at-the-source interpretation for
BSER.\203\ The rule read the legislative history to indicate that the
House and Senate bills that led to the adoption of CAA section 111
``contemplated only control measures that would lead to better design,
construction, operation, and maintenance of an individual source. . .
.'' \204\ The EPA disagrees with this interpretation of the legislative
history. The ACE Rule itself acknowledged that the 1970 CAA Amendments
legislative history also included broader language in describing the
types of measures that were to provide the basis for the standards of
performance.\205\ In addition, the ACE Rule went on to narrow its
argument about legislative history to saying that the 1990 CAA
Amendments made clear only that generation-shifting was precluded.\206\
Id. at 32526 n.62. Thus, the EPA finds that the legislative history
cannot be read to confirm the interpretation that section 111(d) and
(a)(1), by their plain language, limit the BSER to at-the-source
measures.
---------------------------------------------------------------------------

    \203\ 84 FR 32525-26.
    \204\ Id. at 32526.
    \205\ Id. at 32526 n.61. The ACE Rule argued that the canon of
ejusdem generis required that those broader terms be interpreted to
denote at-the-source measures but ejusdem generis is an aid in
statutory construction and should not be used to narrow the meaning
of a statute beyond its intention. Karl N. Llwellyn, Remarks on the
Theory of Appellate Decision and the Rules or Canons about how
Statutes are to be Construed, 3 Vanderbilt L. Rev. 395, 405 & n.46
(1950).
    \206\ Id. at 32526 n.61.
---------------------------------------------------------------------------

    There is another reason why the ACE Rule's interpretation is
incorrect: it appears to be inconsistent with many EPA determinations
in previous CAA section 111 rulemakings that certain control measures
qualified as the BSER. This is because although those measures apply at
the source and reduce

emissions at the source, they also have components that are outside the
source. In West Virginia, the Supreme Court recognized that the EPA
had, in prior rules, identified as the BSER these ```more traditional
air pollution control measures.' ''\207\ The Court made this point as
part of its reasoning that the CPP's generation-shifting BSER--which
the Court stated differed from these traditional measures--raised a
major question. The Court quoted the CPP as describing these
traditional measures as ```efficiency improvements, fuel-switching,''
and `add-on controls.' '' \208\ The Court noted that these types of
controls have several characteristics: they ``reduce pollution by
causing the regulated source to operate more cleanly.'' \209\ They ``
`allow[ ] regulated entities to produce as much of a particular good as
they desire provided that they do so through an appropriately clean (or
low-emitting) process.' '' '\210\ They are ``technology-based . . .
[and] focuse[d] on improving the emissions performance of individual
sources.'' \211\
---------------------------------------------------------------------------

    \207\ 142 S.Ct.at 2611 (citing 80 FR 64662, 64784 (Oct. 23,
2015)).
    \208\ Id. (citing 80 FR 64784).
    \209\ 142 S.Ct. at 2610.
    \210\ Id. (quoting 80 FR 64738).
    \211\ Id. at 2611.
---------------------------------------------------------------------------

    However, many of these traditional controls also have components
that are outside the source. One example includes what the Court,
quoting the CPP, identified as ``fuel-switching.'' \212\ Fuel-switching
entails the use of lower-emitting fuels. These include fuels that have
been cleaned, or processed, to reduce their level of pollutants,\213\
such as coal or oil that has been desulfurized. Desulfurization reduces
the amount of sulfur in the fuel, which means that the fuel can be
combusted with fewer SO2 emissions. Importantly, the process
of desulfurization typically occurs off-site and is undertaken by third
parties. Congress itself recognized this in the 1977 CAA Amendments.
Specifically, Congress revised CAA section 111(a)(1) to identify the
basis for standards of performance for new fossil fuel-fired stationary
sources as a ``technological system of continuous emission reduction,''
including ``precombustion cleaning or treatment of fuels.'' \214\ The
1977 House Committee report stated that fuel cleaning includes ``oil
desulfurization at the refinery.'' \215\ The report added that fuel
cleaning includes ``various coal-cleaning technologies,'' which
generally are also conducted off-site by third parties.\216\ As noted
above, in the 1990 CAA Amendments, Congress eliminated many of the
restrictions and other provisions added in the 1977 CAA Amendments by
largely reinstating the 1970 CAA Amendments' definition of ``standard
of performance.'' Nevertheless, there is no indication that in doing
so, Congress intended to preclude the EPA from considering fuel
cleaning off-site by third parties. In fact, the EPA's regulations
promulgated after the 1990 CAA Amendments continue to impose standards
of performance that are based on coal cleaning off-site by third
parties.\217\
---------------------------------------------------------------------------

    \212\ Id.
    \213\ EPA considered fuel cleaning to be within the scope of the
best system of emission reduction beginning immediately after the
adoption of the 1970 CAA Amendments. See U.S. EPA, Background
Information for Proposed New-Source Performance Standards: Steam
Generators, Incinerators, Portland Cement Plants, Nitric Acid
Plants, Sulfuric Acid Plants, Office of Air Programs Tech. Rep. No.
APTD-0711, p. 7 (Aug. 1971) (indicating the ``desirability of
setting sulfur dioxide standards that would allow the use of low-
sulfur fuels as well as fuel cleaning, stack-gas cleaning, and
equipment modifications'' (emphasis added)).
    \214\ 1977 CAA Amendments, section 109, 91 Stat. 700; see also
CAA section 111(a)(7).
    \215\ H.R. Rep. No. 95-294 (May 12, 1977), 1977 CAA Legis. Hist.
at 2655 (emphasis added).
    \216\ Id. EPA recognized in a regulatory analysis of new source
performance standards for industrial-commercial-institutional steam
generating units that the technology ``requires too much space and
is too expensive to be employed at individual industrial-commercial-
institutional steam generating units.'' U.S. EPA, Summary of
Regulatory Analysis for New Source Performance Standards:
Industrial-Commercial-lnstitutional Steam Generating Units of
Greater than 100 Million Btu/hrHeat Input, EPA-450/3-86-005, p. 4-4
(June 1986).
    \217\ 40 CFR 60.49b(n)(4); see also Amendments to New Source
Performance Standards (NSPS) for Electric Utility Steam Generating
Units and Industrial-Commercial-Institutional Steam Generating
Units; Final Rule, 72 FR 32742 (June 13, 2007).
---------------------------------------------------------------------------

    A second example includes what the Court, again quoting the CPP,
identified as ``add-on controls.'' \218\ These controls include air
pollution control devices that are installed at the unit. They
routinely operate by removing air pollutants from a unit's emission
stream and capturing them as a liquid or solid. For example, a baghouse
is an add-on control device that captures particulate matter by
trapping particles as a dust, which must then be disposed of.\219\
Another add-on control device, flue-gas desulfurization, ``scrubs''
acid gases like sulfur dioxide from emissions using a chemical sorbent
that reacts with the pollutant to generate a liquid slurry (wet
scrubbing) or solid residue (dry scrubbing). These captured pollutants
must then be disposed as solid wastes, discharged as wastewater, or
otherwise managed or reused.\220\ The same is true for carbon capture
and sequestration (CCS): the carbon capture control device scrubs
CO2 from the flue gas stream using a solvent; and the
CO2 must then be stored underground.\221\ Downstream
management of captured pollutants is thus a commonplace feature of CAA
section 111 standards.\222\ Downstream management of captured
pollutants is thus a commonplace feature of CAA section 111
standards.\223\
---------------------------------------------------------------------------

    \218\ 142 S.Ct. at 2611.
    \219\ See Sierra Club v. Costle, 657 F.2d 298, 375 (D.C. Cir.
1981).
    \220\ See id. at 323-24 n.69; see also 80 FR 21303, 21340 (April
17, 2015) (governing off-site disposal of solid wastes captured by
air pollution controls at steam units).
    \221\ 80 FR 64549, 64555 (describing CCS and comparing CCS
pollutant disposition to particulate or wet scrubber pollutant
disposition).
    \222\ See, e.g., 80 FR 64582-90 (requiring that an EGU that
captures CO2 assure that it is transferred to an entity
that will dispose of it appropriately; generally describing
oversight of CO2 storage; detailing Department of
Transportation pipeline regulations; detailing requirements for
monitoring, reporting, and verification plans; detailing injection
well requirements under the Safe Drinking Water Act; and detailing
how existing regulations prevent, monitor, and address potential
leakage); 75 FR 54970, 55022-23 (Sept. 9, 2010) (disposal of
wastewater and solid waste from CAA section 111 standard for
Portland cement plants); 54 FR 34008, 34015 (Aug. 17, 1989) (waste
disposal impacts of standard of performance for sulfur oxide
emissions for fluid catalytic cracking unit regenerators).
    \223\ See 80 FR 64549, 64555 (describing CCS and comparing CCS
pollutant disposition to particulate or wet scrubber pollutant
disposition).
---------------------------------------------------------------------------

    Indeed, CAA section 111(a)(1) by its terms recognizes that
``system[s] of emission reduction'' may entail off-site disposition of
pollutants. The provision states that the EPA must consider ``nonair
quality health and environmental impact'' when determining the BSER.
Congress adopted this phrase in the 1977 CAA Amendments.\224\ As the
legislative history stated, Congress added this phrase so that
``environmental impacts would be required to be considered in
determining best technology which has been adequately demonstrated.''
\225\ In making this addition, Congress codified the D.C. Circuit's
holding in Essex Chem. Corp. v. Ruckelshaus, 486 F.2d 427, 438-39 (D.C.
Cir. 1973), cert. denied, 416 U.S. 969 (1974).\226\ In Essex Chem.
Corp., the D.C. Circuit required that EPA ``take into account counter-
productive environmental effects'' when determining whether a control
measure qualifies as the BSER, including ``disposal problems'' related
to the control measure's captured pollutants. The Court remanded the
NSPS at issue because there was no evidence that the EPA had considered
``the significant land or water pollution potential

resulting from disposal of the [scrubber system's] liquid purge
byproduct.'' \227\ That the ACE Rule's interpretation that CAA section
111 limits the BSER to at-the-source measures may be inconsistent with
the EPA's prior determinations that traditional control measures like
clean fuels and add-on controls qualified as the BSER provides another
reason to reject that interpretation.
---------------------------------------------------------------------------

    \224\ Pub. L. 95-95, section 109(c)(1)(A) (Aug. 7, 1977), 91
Stat. 699-700.
    \225\ H.R. Rep. No. 95-294 at 190 (May 12, 1977).
    \226\ Id.
    \227\ Id. See Portland Cement Ass'n v. Ruckelshaus, 486 F.2d
375, 385 n.42 (D.C. Cir. 1973) (``The standard of the ``best
system'' is comprehensive, and we cannot imagine that Congress
intended that `best' could apply to a system which did more damage
to water than it prevented to air.'').
---------------------------------------------------------------------------

    It should be noted that many of the reasons noted above are
comparable to the reasoning by the D.C. Circuit to support its decision
in ALA that the ACE Rule was incorrect in interpreting CAA section 111
to restrict the BSER to at-the-source measures.\228\ The EPA agrees
with the D.C. Circuit's reasoning.
---------------------------------------------------------------------------

    \228\ 985 F.3d 914, 955-41 (D.C. Cir. 2021).
---------------------------------------------------------------------------

    In West Virginia, the Supreme Court held that the CPP's generation-
shifting BSER violated the major question doctrine, and the Court
vacated ALA on the basis of that holding.\229\ However, the Court
declined to address the ACE Rule's interpretation of CAA section
111.\230\ Thus, its opinion does not cast doubt on the EPA's reasons
for rejecting the ACE Rule's interpretation, as noted above and in ALA.
Several commenters argued that West Virginia indicates that control
measures that the commenters considered comparable to the generation-
shifting BSER of the CPP, including trading programs and other measures
that controlled designated facilities in the aggregate, were also
precluded from inclusion as the BSER under the major question
doctrine.\231\ Other commenters disagreed, arguing that West Virginia
identifies distinctions among those programs, so that the major
question doctrine would not necessarily apply.\232\ However, as noted
in the proposal, in this action, the EPA is not addressing what types
of controls, in addition to the generation-shifting BSER of the CPP,
would be precluded under CAA section 111 by the major question
doctrine. Instead, the EPA will evaluate particular controls against
the doctrine, as appropriate, when the EPA considers those controls in
future rulemakings under CAA section 111.
---------------------------------------------------------------------------

    \229\ 142 S.Ct. at 2610, 2614, 2615-16.
    \230\ Id. at 2615-16.
    \231\ API Comment Letter on ``Adoption and Submittal of State
Plans for Designated Facilities; Implementing Regulations Under
Clean Air Act Section 111(d)'' (``Subpart Ba''), EPA-HQ-OAR-2021-
0527-0074 at 8; Lignite Energy Council Comment Letter on Subpart Ba,
EPA-HQ-OAR-2021-0527-0100 at 8-9.
    \232\ Energy Strategy Coalition Comment Letter on Subpart Ba,
EPA-HQ-OAR-2021-0527-0088 at 6 (noting that West Virginia
distinguished the trading program in the Clean Air Mercury Rule,
which was based on technological controls, from the trading program
in the CPP).
---------------------------------------------------------------------------

2. Minor Amendments or Clarifications
    The EPA proposed to amend the regulatory text in subpart Ba to
address several editorial and other minor clarifications and is
finalizing the amendments as described below. Except as noted
specifically below, commenters supported these revisions to the
regulatory text.
    a. The EPA is finalizing amendments to the applicability provision
for subpart Ba under 40 CFR 60.20a, with slight revision from as
proposed. As discussed in section II.B. of this preamble, the revised
applicability provision clarifies that the provisions of subpart Ba are
applicable to an EG published after July 8, 2019. The EPA is finalizing
the proposed removal of text that included ``if implementation of such
final guideline is ongoing'' because there are no EGs the
implementation of which is ongoing; \233\ thus, leaving this language
in the regulation would be needlessly confusing. Emission guidelines
issued on and prior to July 8, 2019, and pursuant to CAA section 129
are subject to the provisions of subpart B. Also, in response to
comment that the term ``final emission guideline'' is unclear, the EPA
is adding the term ``in the Federal Register'' to 40 CFR 60.20a(a) to
clarify the publication in the Federal Register determines the
applicability date. Further clarification of the term ``final emission
guideline'' is available in 40 CFR 60.22a(a). A commenter also noted
that the proposed rule text deleted all references to ``subpart C of
this part'' and removing this language means that it would apply to all
EGs in 40 CFR part 60 (that are published after July 8, 2019),
including those for incinerators addressed by CAA section 129. This was
not the EPA's intent. Therefore, as noted in section III.G.2.b. of this
preamble, the EPA is amending the definition of EG within subpart Ba to
clarify that subpart Ba does not apply to EGs promulgated under CAA
section 129.
---------------------------------------------------------------------------

    \233\ The Municipal Solid Waste Landfills EG, which is currently
being implemented, has its own applicability provisions and is
subject to subpart B.
---------------------------------------------------------------------------

    b. The EPA is finalizing revisions to 40 CFR 60.21a(e), 60.22a(c),
and 60.24a(c) and (f)(1) and (2), largely as proposed, at 40 CFR
60.21a(e), 60.22a(c), and 60.24a(c) and (i)(1) and (2) respectively
(differences in numbering are due to provisions changing location in
the final regulations relative to proposal). These revisions delete
``subpart C'' from these provisions because EGs can be codified in
other subparts of this part and not only in subpart C of this part. In
response to a comment requesting clarification, 40 CFR 60.21a(e) is
also amended clarify that the definition of emission guidelines for
purposes of subpart Ba excludes guidelines promulgated pursuant to CAA
section 129. As discussed above, EGs under CAA section 129 are subject
to the provisions of subpart B.
    c. The EPA is finalizing as proposed an editorial amendment to 40
CFR part 60, subpart A, at Sec.  60.1(a) to add a reference to subpart
Ba. The applicability provision in 40 CFR 60.1(a) states that
``[e]xcept as provided in subparts B and C, the provisions of this part
apply to the owner or operator of any stationary source which contains
an affected facility, the construction or modification of which is
commenced after the date of publication in this part of any standard
(or, if earlier, the date of publication of any proposed standard)
applicable to that facility.'' We are amending this provision to
include reference to subpart Ba in addition to subparts B and C.
    d. A minor editorial correction at 40 CFR 60.22a(b)(3) amends the
term ``nonair quality health environmental effects'' to ``nonair
quality health and environmental effects''.
3. Submission of Emissions Data and Related Information
    The EPA is finalizing as proposed amendments to 40 CFR 60.25a(a)
that delete reference to 40 CFR part 60, appendix D, because the system
specified for information submittal by the appendix is no longer in use
and clarify that the applicable EG will specify the system for
submission of the inventory of designated facilities, including
emission data for the designated pollutants and any additional required
information related to emissions. The EPA also proposed to delete the
term ``related to emissions'' in 40 CFR 60.25a(a). A commenter noted as
proposed this deletion caused the provision to be too vague. The EPA
agrees that the term ``related to emissions'' should be retained to
maintain the original and proper context of this provision. The term is
retained by this final action.
4. State Permit and Enforcement Authority
    Questions have previously arisen as to whether states may establish
standards of performance and other plan requirements as part of state
permits

and administrative orders. The EPA is confirming with this final action
that subpart Ba allows for standards of performance and other state
plan requirements to be established as part of state permits and
administrative orders, which then must be incorporated into the state
plan. See 40 CFR 60.27a(g)(2)(ii).
    However, the EPA notes that the permit or administrative order
alone may not be sufficient to meet the requirements of an EG or the
implementing regulations, including the completeness criteria under 40
CFR 60.27a(g). For instance, a plan submittal must include supporting
material demonstrating the state's legal authority to implement and
enforce each component of its plan, including the standards of
performance, 40 CFR 60.27a(g)(2)(iii), as well as a demonstration that
each emission standard is quantifiable, non-duplicative, permanent,
verifiable, and enforceable. Id. at Sec.  60.27a(a)(2)(vi). In
addition, the specific EGs may also require demonstrations that may not
be satisfied by terms of a permit or administrative order. To the
extent that these and other requirements are not met by the terms of
the incorporated permits and administrative orders, states will need to
include materials in a state plan submission demonstrating how the plan
meets those requirements. If a state does choose to use permits or
administrative orders to establish standards of performance, it needs
to demonstrate that it has the legal authority to do so. These
implementing regulations do not themselves provide any independent or
additional authority to issue permits and administrative orders under
states' EPA approved title I and title V permitting programs.

IV. Summary of Cost, Environmental, and Economic Impacts

    In amending general implementing regulations, this final action
does not independently impose any requirements and therefore does not
directly incur any costs or benefits. However, the amendments finalized
in this action can impact the costs and benefits of future EGs subject
to subpart Ba. The potential impacts of these amendments as reflected
in an EG will vary greatly depending on the source category, number and
location of designated facilities, and the designated pollutant and
potential controls addressed by the EG. Of note, the EPA may propose to
supersede these general provisions in an EG as needed and with
appropriate justification. Individual EGs are subject to notice and
comment rulemaking, providing the opportunity for stakeholders,
including the public, to consider the impacts of implementing or
superseding these general implementing regulations in the course of
those rulemaking actions.
    As described in detail in section III.A. of this preamble, the EPA
is finalizing amendments to subpart Ba to replace timelines vacated by
the D.C. Circuit in ALA \234\ and to improve and update other
provisions within subpart Ba. This section considers general impacts
that could result from the amendments finalized in this action as
adopted by an EG.
---------------------------------------------------------------------------

    \234\ Am. Lung Ass'n v. EPA, 985 F.3d 914, 991 (D.C. Cir. 2021).
---------------------------------------------------------------------------

    As discussed in section III.A. of this preamble, the EPA does not
interpret the D.C. Circuit's direction to require the Agency to
quantitatively evaluate the impacts of potential subpart Ba framework
timelines, but rather to consider the balance between the public health
and welfare benefits resulting from appropriate and reasonable
deadlines for the implementation of EGs and the time needed for the
technical, administrative, and legislative actions needed to develop
and adopt approvable state or Federal plans. The EPA expects that the
amendments to subpart Ba finalized in this action will improve the
implementation of EGs under CAA section 111(d). In particular, the EPA
expects that the timelines finalized both appropriately accommodate
state and EPA processes to develop and evaluate plans to effectuate an
EG and are consistent with the objective of CAA section 111(d) to
ensure that designated facilities expeditiously control emissions of
pollutants that the EPA has determined may be reasonably anticipated to
endanger public health or welfare.
    While the EPA initially proposed a 15-month deadline for state plan
submissions following the promulgation of an EG (87 FR 79176, Dec. 23,
2022), most commenters, including states and state organizations,
indicated that 15 months could not accommodate the technical,
administrative, and legal steps necessary to develop and adopt an
approvable state plan. Based on the comments and additional information
received, the EPA is finalizing 18 months for state plan submissions
after promulgation of a final EG, and finds that the additional time,
compared with the 9 months provided in subpart B, will better
accommodate states' processes to develop and adopt approvable plans and
will most efficiently effectuate the applicable EG. Under an 18-month
state plan submission timeframe, the costs of developing a state plan
under an applicable EG subject to subpart Ba, compared with the 9
months provided by subpart B, may be spread over 9 additional months.
With this state plan submittal timeline, the EPA is providing states
sufficient time to develop approvable implementation plans for their
designated facilities that adequately address public health and
environmental objectives. A timeline that is insufficient for states to
conduct, inter alia, the appropriate technical analysis and public
engagement may preclude them from timely adopting and submitting
approvable state plans, which could ultimately delay the implementation
of emission reductions. In addition, a successful submittal of
approvable state plans will avoid an attendant expenditure of Federal
resources associated with the development of a Federal plan.
    After receiving a state plan, the EPA first must determine if the
plan is complete. The EPA is finalizing amendments to its determination
of completeness so the timeframe for such determination is streamlined
from six months to 60 days from receipt of the state plan submission
(see section III.A.2. of this preamble). If the EPA determines a state
plan submission is complete, it then evaluates the plan to determine
whether it satisfies the applicable requirements. The Agency proposes
an action (e.g., plan approval or plan disapproval) and then finalizes
its action pursuant to a notice-and-comment rulemaking process. As
described in detail in sections III.A.3. and III.A.4. of this preamble,
the EPA is finalizing a 12-month period for the EPA to take final
action on a state plan after a submission is found to be complete. The
EPA is also finalizing a 12-month timeline for the EPA to promulgate a
Federal plan, which runs from either the state plan deadline if a state
has failed to submit a state plan, 60 days following the state plan
deadline if a state has submitted a plan by the deadline and the EPA
determines it is incomplete, or from the date the EPA finalizes
disapproval of a state plan submission. As described in detail in
section III. of this preamble, because these timeframes provide for the
minimum time reasonably necessary for the EPA to accomplish propose and
finalize a Federal plan, the EPA expects these timeframes will minimize
the impacts on public health and welfare to the extent possible while
ensuring that an EG is expeditiously implemented.
    As described in detail in section III.A.5. of this preamble, the
EPA is finalizing a requirement that state plans include IoPs if the
plan requires final

compliance with standards of performance later than 20 months after the
plan submission deadline. The compliance schedule, as defined in
subpart Ba (40 CFR 60.21a(g)) is a legally enforceable schedule
specifying a date or dates by which a source or category of sources
must comply with specific standards of performance contained in a plan.
If final compliance for a source to meet their standards of performance
is more than 20 months after the state plan submittal deadline, the
plan must include IoPs, which are defined steps to achieve compliance
(e.g., submittal of a control plan, awarding of contracts for emission
control systems or process modification, etc.). This 20 month timeline
is the trigger for when IoPs must be included in a state plan. An EG
will specify what the IoPs are and associated compliance schedules. The
EPA considers this slightly longer timeline than is required under
subpart B reasonable given that the EPA is also, in this action,
extending the timelines for state plan submission under subpart Ba. The
EPA notes that IoPs do not, on their own, govern how expeditiously
emission reductions are achieved: this is dictated by the final
compliance date, which is established in an individual EG.
Additionally, any specific requirements associated with IoPs, including
extended or truncated timelines, would be included in the EG, as these
are dependent on the source type, pollutant, and control strategy
addressed.
    The EPA is also finalizing amending subpart Ba to enhance
requirements for reasonable notice and opportunity for public
participation. In particular, the EPA is requiring that states, as part
of the state plan development or revision process, provide
documentation that they have conducted meaningful engagement with a
broad range of pertinent stakeholders and/or their representatives.
Pertinent stakeholders include communities most affected by and
vulnerable to the impacts of the plan or plan revision (see section
III.C. of this preamble).
    Overall, the EPA expects the amendments being finalized in this
action will benefit the states in the development of approvable state
plans. The EPA expects that the amendments associated with meaningful
engagement with pertinent stakeholders will potentially increase the
amount of information the states can use in designing state plans,
which may increase both the level of resources states will need to
employ in the development of an approvable plan, as well as the
resulting health and welfare benefits of the plan. In addition to
health and welfare benefits, there are also administrative benefits of
engaging with stakeholders and receiving pertinent information as a
state plan is being developed. Such engagement may improve the record
for the state's plan and reduce the amount of comments received when
the state plan is proposed to the public, which would reduce the amount
of effort employed after proposal to address issues raised by the
public and stakeholders.
    There is variation and uncertainty in determining the magnitude of
impacts, both to states and the public, resulting from amendments
associated with meaningful engagement. First, the EPA notes that the
meaningful engagement provisions being finalized in this action are
largely procedural in nature and do not prescribe any particular set of
actions or activities that states must undertake. The potential costs
and benefits will therefore be determined in significant part by
choices that are within states' discretion. Second, the impacts of
conducting meaningful engagement will be highly dependent on the number
and location of designated facilities addressed by an EG, as well as on
the type of health or environmental impacts of the associated
emissions. If stakeholder and public involvement pursuant to the
meaningful engagement provisions does not generate a large number of
specific and unique comments, data, or other considerations, then the
level of effort states will employ to review them will be lower in
comparison to when meaningful engagement comments are voluminous. It
might also be expected that less input and fewer comments might, in
certain cases, have an adverse impact on the ability of a state plan to
fulfill its health and welfare objectives.
    To the extent that states already conduct significant engagement
with pertinent stakeholders, the meaningful engagement amendments will
most likely not result in additional costs. Conversely, states that do
not have engagement procedures already in place may be required to
increase their level of effort to engage with pertinent stakeholders.
The burden and benefits of meaningful engagement for the pertinent
stakeholders will also be highly dependent on the EG and associated
variables such as, but not limited to, the geographical distribution of
the facilities and communities impacted, available modes of
participation for those areas, the pollutants addressed, and the range
of options available to the state and facilities for meeting the EG
standards. The burden and benefits to pertinent stakeholders may be
difficult to quantify, but overall their engagement will be voluntary
and is anticipated to result in feedback that may improve the resulting
health and welfare benefits of the state plan as perceived and
experienced, particularly by those in communities most affected by and
vulnerable to the impacts of the plan.
    The EPA is also finalizing revisions to the RULOF provisions in
subpart Ba. The amendments included in this final action are intended
to provide clarity for states to ensure that less-stringent standards
of performance for particular designated facilities are consistent with
the statutory requirements, as well as a consistent framework for EPA
to evaluate such standards across EGs and states (see section III.E. of
this preamble).
    The magnitude of impacts, both to states and the public, resulting
from the final RULOF amendments will vary depending on the particular
EG to which the final provisions would apply. As explained in section
III.E.2. of this preamble, the EPA believes Congress intended RULOF as
a mechanism for states to apply a less-stringent standard of
performance in the unusual circumstances in which the degree of
emission limitation determined by the EPA is not reasonable for a
particular designated facility. Additionally, states are not required
to invoke the RULOF provision in any particular instance and may choose
not to do so, even if a particular designated facility's circumstances
meet the threshold specified in the regulations. If a state does not
invoke RULOF in their state plan, then the amendments will not result
in any additional costs. If a state does invoke RULOF in their state
plan, then the amendments could, in certain circumstances, result in an
increased level of effort to develop standards of performance for
certain sources. As such, the RULOF amendments could potentially
increase the level of resources states will need to employ in the
development of an approvable plan. However, because the amendments
clarify is required in order for a less-stringent standard pursuant to
RULOF to satisfy the statutory requirements, the amendments reduce the
uncertainty of states and designated facilities in the development of
such standards. This in turn could result in a decrease in the amount
of time that a state that wished to invoke RULOF would need, relative
to a situation where the requirements were less defined, by avoiding
significant back and forth with the EPA and the sources in the state
during state plan development. Overall, the EPA expects the RULOF
amendments will benefit the states in the development of

approvable state plans and therefore result in benefits to public
health and welfare.
    Finally, the EPA expects that the requirements for electronic
submittal and that the availability of the optional regulatory
mechanisms being finalized in this action will improve flexibility and
efficiency in the call for and submission, review, approval, and
implementation of state plans, and thus will overall result in benefits
to the states, the EPA, designated facilities, and public health and
welfare. In addition, the EPA expects the requirements for electronic
submittal will increase the ease and efficiency of data submittal and
data accessibility and benefit the states and the EPA. Electronic
submittal will also improve the Agency's efficiency and effectiveness
in the receipt and review of state plans.
    The EPA expects that the overall impacts of the implementation of
the amendments to subpart Ba finalized in this action will improve the
implementation of EGs under CAA section 111(d).

V. Statutory and Executive Order Reviews

    Additional information about these Statutory and Executive orders
can be found at https://www.epa.gov/laws-regulations/laws-and-executive-orders.

A. Executive Order 12866: Regulatory Planning and Review; Executive
Order 13563: Improving Regulation and Regulatory Review; and Executive
Order 14094: Modernizing Regulatory Review

    This action is a ``significant regulatory action'' as defined in
Executive Order 12866, as amended by Executive Order 14094.
Accordingly, the EPA submitted this action to the Office of Management
and Budget (OMB) for Executive Order 12866 review. Documentation of any
changes made in response to the Executive Order 12866 review is
available in the docket.

B. Paperwork Reduction Act (PRA)

    This action does not impose an information collection burden under
the Paperwork Reduction Act. The requirements in subpart Ba do not
themselves require any reporting and recordkeeping activities, and no
Information Collection Request (ICR) was submitted in connection with
the original promulgation of subpart Ba or the amendments we are
finalizing at this time. Any recordkeeping and reporting requirements
are imposed only through the incorporation of specific elements of
subpart Ba in the individual emission guidelines, which have their own
ICRs.

C. Regulatory Flexibility Act (RFA)

    I certify that this action will not have a significant economic
impact on a substantial number of small entities. This final rule will
not impose any requirements on small entities. Specifically, this
action addresses processes related to state plans for implementation of
EGs established under CAA section 111(d).

D. Unfunded Mandates Reform Act (UMRA)

    This action does not contain an unfunded mandate of $100 million or
more as described in UMRA, 2 U.S.C. 1531-1538, and does not
significantly or uniquely affect small governments. This final action
does not contain a Federal mandate that may result in expenditures of
$100 million or more for state, local, and Tribal governments, in the
aggregate or the private sector in any 1 year.
    This final action is also not subject to the requirements of
section 203 of UMRA because, as described in 2 U.S.C. 1531-38, it
contains no regulatory requirements that might significantly or
uniquely affect small governments. This action imposes no enforceable
duty on any local, or Tribal governments or the private sector.
However, this action imposes enforceable duties on states. This action
does not meaningfully require additional mandates on states beyond what
is already required of them and will not impose a burden in excess of
$100 million.

E. Executive Order 13132: Federalism

    This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the National Government and the states, or on the distribution of power
and responsibilities among the various levels of government. The EPA
believes, however, that this action may be of significant interest to
state governments.
    Subpart Ba requirements apply to states in the development and
submittal of state plans pursuant to emission guidelines promulgated
under CAA section 111(d) after July 8, 2019, to the extent that an EG
does not supersede the requirements of subpart Ba. This action
finalizes amendments to certain requirements for development,
submission, and approval processes of state plans under CAA section
111(d). In particular, the amendments associated with state plan
submission deadlines, RULOF provisions, meaningful engagement, and
regulatory mechanisms may be of significant interest to state
governments. In section IV of this preamble, the EPA summarizes the
potential cost, environmental, and economic impacts of the
implementation (through individual emission guidelines) of the
amendments to subpart Ba being finalized in this action. Overall, the
EPA expects these amendments will benefit the states in the development
of approvable state plans.
    The EPA notes that notice and comment procedures required for the
promulgation of individual EGs will provide opportunity for states to
address issues related to federalism based on specific application of
subpart Ba requirements to that particular EG.

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

    This action does not have Tribal implications as specified in
Executive Order 13175. It would not impose substantial direct
compliance costs on Tribal governments that have designated facilities
located in their area of Indian country. Tribes are not required to
develop plans to implement the guidelines under CAA section 111(d) for
designated facilities. A tribe with an approved TAS under TAR for CAA
111(d) is not required to resubmit TAS approval to implement an EG
subject to subpart Ba. This action also will not have substantial
direct costs or impacts on the relationship between the Federal
Government and Indian tribes or on the distribution of power and
responsibilities between the Federal Government and Indian tribes, as
specified in Executive Order 13175. Thus, Executive Order 13175 does
not apply to the action.

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

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

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

    This action is not a ``significant energy action'' because it will
not have a significant adverse effect on the supply, distribution or
use of energy. Specifically, this action addresses the

submission and adoption of state plans for implementation of EGs
established under CAA section 111(d).

I. National Technology Transfer and Advancement Act (NTTAA)

    This rulemaking does not involve technical standards.

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

    Executive Order 12898 (59 FR 7629, February 16, 1994) directs
Federal agencies, to the greatest extent practicable and permitted by
law, to make environmental justice part of their mission by identifying
and addressing, as appropriate, disproportionately high and adverse
human health or environmental effects of their programs, policies, and
activities on minority populations (people of color and/or indigenous
peoples) and low-income populations.
    The EPA believes that it is not practicable to assess whether the
human health or environmental conditions that exist prior to this
action result in disproportionate and adverse effects on people of
color, low-income populations and/or indigenous peoples. The 40 CFR
part 60, subpart Ba, provisions are the implementing regulations for
states to plan in response to individual EGs, and these individual EGs
are applicable to specific pollutants from specified categories of
existing sources. It is not possible to identify or assess human health
and environmental conditions that will be impacted by this rule because
this rule does not address a particular set of sources or a particular
pollutant. This action is revising the implementing regulations and
does not directly impact environmental justice communities or result in
new disproportionate and adverse effects.
    The EPA identified and addressed environmental justice concerns by
specifying new requirements for meaningful engagement with pertinent
stakeholders, which includes communities most affected by and/or
vulnerable to the impacts of a state plan.
    The information supporting this Executive order review is contained
in section III.C. and section III.E.3.f. of this action.

K. Congressional Review Act (CRA)

    This action is subject to the CRA, and the EPA will submit a rule
report to each House of the Congress and to the Comptroller General of
the United States. This action is not a ``major rule'' as defined by 5
U.S.C. 804(2).

List of Subjects in 40 CFR Part 60

    Environmental protection, Administrative practice and procedures,
Air pollution control, Intergovernmental relations, Reporting and
recordkeeping requirements.

Michael S. Regan,
Administrator.
    For the reasons set out in the preamble, title 40, chapter I of the
Code of Federal Regulations is amended as follows:

PART 60--STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES

0
1. The authority citation for part 60 continues to read as follows:

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

0
2. Amend Sec.  60.1 by revising paragraph (a) to read as follows:

Sec.  60.1  Applicability.

    (a) Except as provided in subparts B, Ba, and C of this part, the