Proposed Rule2024-14612
Air Plan Partial Approval and Partial Disapproval; Missouri; Regional Haze
Primary source
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Published
July 3, 2024
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to partially approve and partially disapprove a revision to Missouri's State Implementation Plan (SIP) submitted on August 26, 2022, to satisfy applicable requirements under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second planning period. As required by section 169A of the Clean Air Act, the Federal Regional Haze Rule calls for state and Federal agencies to work together to improve visibility, including Regional Haze, in 156 national parks and wilderness areas. The rule requires the states, in coordination with the EPA, the National Parks Service (NPS), the U.S. Fish and Wildlife Service (FWS), the U.S. Forest Service (FS), and other interested parties, to develop and implement air quality protection plans in which states revise their long-term strategies (LTS) for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility in these mandatory Class I Federal areas. Disapproval does not start a mandatory sanctions clock.
Full Text
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<title>Federal Register, Volume 89 Issue 128 (Wednesday, July 3, 2024)</title>
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[Federal Register Volume 89, Number 128 (Wednesday, July 3, 2024)]
[Proposed Rules]
[Pages 55140-55168]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-14612]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R07-OAR-2024-0286; FRL-12046-01-R7]
Air Plan Partial Approval and Partial Disapproval; Missouri;
Regional Haze
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
partially approve and partially disapprove a revision to Missouri's
State Implementation Plan (SIP) submitted on August 26, 2022, to
satisfy applicable requirements under the Clean Air Act (CAA) and the
EPA's Regional Haze Rule (RHR) for the program's second planning
period. As required by section 169A of the Clean Air Act, the Federal
Regional Haze Rule calls for state and Federal agencies to work
together to improve visibility, including Regional Haze, in 156
national parks and wilderness areas. The rule requires the states, in
coordination with the EPA, the National Parks Service (NPS), the U.S.
Fish and Wildlife Service (FWS), the U.S. Forest Service (FS), and
other interested parties, to develop and implement air quality
protection plans in which states revise their long-term strategies
(LTS) for making reasonable progress towards the national goal of
preventing any future, and remedying any existing, anthropogenic
impairment of visibility in these mandatory Class I Federal areas.
Disapproval does not start a mandatory sanctions clock.
DATES: Comments must be received on or before August 2, 2024.
ADDRESSES: You may send comments, identified by Docket ID No. EPA-R07-
OAR-2024-0286 to <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online
instructions for submitting comments.
Instructions: All submissions received must include the Docket ID
No. for this rulemaking. Comments received will be posted without
change to <a href="https://www.regulations.gov/">https://www.regulations.gov/</a>, including any personal
information provided. For detailed instructions on sending comments and
additional information on the rulemaking process, see the ``Written
Comments'' heading of the SUPPLEMENTARY INFORMATION section of this
preamble.
FOR FURTHER INFORMATION CONTACT: Ashley Keas, Environmental Protection
Agency, Region 7 Office, Air and Radiation Division, 11201 Renner
Boulevard, Lenexa, Kansas 66219; telephone number: (913) 551-7629;
email address: <a href="/cdn-cgi/l/email-protection#f9929c988ad7988a91959c80b99c8998d79e968f"><span class="__cf_email__" data-cfemail="ff949a9e8cd19e8c97939a86bf9a8f9ed1989089">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION: Throughout this document ``we,'' ``us,'' and
``our'' refer to the EPA.
Table of Contents
I. Written Comments
II. What is being addressed in this document?
III. Background and Requirements for Regional Haze Plans
A. Regional Haze Background
B. Roles of Agencies in Addressing Regional Haze
IV. Requirements for Regional Haze Plans for the Second
Implementation Period
A. Identification of Class I Areas
B. Calculation of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
C. Long-Term Strategy for Regional Haze
D. Reasonable Progress Goals
E. Monitoring Strategy and Other State Implementation Plan
Requirements
F. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
G. Requirements for State and Federal Land Manager Coordination
V. The EPA's Evaluation of Missouri's Regional Haze Submission for
the Second Implementation Period
A. Background on Missouri's First Implementation Period SIP
Submission
B. Missouri's Second Implementation Period SIP Submission and
the EPA's Evaluation
C. Identification of Class I Areas
D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
E. Long-Term Strategy for Regional Haze
1. Source Selection
2. Four-Factor Analysis
3. Additional Long-Term Strategy Requirements
F. Reasonable Progress Goals
G. Monitoring Strategy and Other Implementation Plan
Requirements
H. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
I. Requirements for State and Federal Land Manager Coordination
VI. What action is the EPA proposing to take?
VII. Environmental Justice Considerations
VIII. Statutory and Executive Order Reviews
I. Written Comments
Submit your comments, identified by Docket ID No. EPA-R07-OAR-2024-
0286, at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Once submitted, comments cannot
be edited or removed from <a href="http://Regulations.gov">Regulations.gov</a>. The EPA may publish any
comment received to its public docket. Do not submit electronically any
information you consider to be Confidential Business Information (CBI)
or other information whose disclosure is restricted by statute.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points you wish to make. The EPA
will generally not consider comments or comment contents located
outside of the primary submission (i.e., on the web, cloud, or other
file sharing system). For additional submission methods, the full EPA
public comment policy, information about CBI or multimedia submissions,
and general guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
II. What is being addressed in this document?
On August 26, 2022, the Missouri Department of Natural Resources
(MoDNR) submitted a plan to the EPA to satisfy the regional haze
program requirements pursuant to CAA sections 169A and 40 CFR 51.308.
The EPA is proposing to partially approve and partially disapprove
Missouri's Regional Haze plan for the second planning period.
Consistent with section 110(k)(3) of the CAA, the EPA may partially
approve portions of a submittal
[[Page 55141]]
if those elements meet all applicable requirements and may disapprove
the remainder so long as the elements are fully separable.\1\ As
required by section 169A of the CAA, the Federal RHR calls for state
and Federal agencies to work together to improve visibility in 156
national parks and wilderness areas. The rule requires the states, in
coordination with the EPA, NPS, FWS, FS, and other interested parties,
to develop and implement air quality protection plans to reduce the
pollution that causes visibility impairment. Visibility impairing
pollutants include fine and coarse particulate matter (PM) (e.g.,
sulfates, nitrates, organic carbon, elemental carbon, and soil dust)
and their precursors (e.g., sulfur dioxide (SO<INF>2</INF>), nitrogen
oxides (NO<INF>X</INF>), and, in some cases, volatile organic compounds
(VOC) and ammonia (NH<INF>3</INF>)). As discussed in further detail
below, the EPA is proposing to find that Missouri has submitted a
Regional Haze plan that does not meet all the Regional Haze
requirements for the second planning period. For the reasons described
in this document, the EPA is proposing to approve the elements of
Missouri's plan related to requirements contained in 40 CFR
51.308(f)(1), (f)(5), (f)(6), and (g)(1) through (g)(5). The EPA is
proposing to disapprove the elements of Missouri's plan related to
requirements contained in 40 CFR 51.308(f)(2), (f)(3), and (i). The
State's submission can be found in the docket for this action.
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\1\ See CAA section 110(k)(3) and July 1992 EPA memorandum
titled ``Processing of State Implementation Plan (SIP) Submittals''
from John Calcagni, at <a href="https://www.epa.gov/sites/default/files/2015-07/documents/procsip.pdf">https://www.epa.gov/sites/default/files/2015-07/documents/procsip.pdf</a>.
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III. Background and Requirements for Regional Haze Plans
A. Regional Haze Background
In the 1977 CAA Amendments, Congress created a program for
protecting visibility in the nation's mandatory Class I Federal areas,
which include certain national parks and wilderness areas.\2\ CAA
section 169A. The CAA establishes as a national goal the ``prevention
of any future, and the remedying of any existing, impairment of
visibility in mandatory class I Federal areas which impairment results
from manmade air pollution.'' CAA section 169A(a)(1). The CAA further
directs the EPA to promulgate regulations to assure reasonable progress
toward meeting this national goal. CAA section 169A(a)(4). On December
2, 1980, the EPA promulgated regulations to address visibility
impairment in mandatory Class I Federal Areas (hereinafter referred to
as ``Class I Areas'') that is ``reasonably attributable'' to a single
source or small group of sources. (45 FR 80084, December 2, 1980).
These regulations, codified at 40 CFR 51.300 through 51.307,
represented the first phase of the EPA's efforts to address visibility
impairment. In 1990, Congress added section 169B to the CAA to further
address visibility impairment, specifically, impairment from Regional
Haze. CAA section 169B. The EPA promulgated the RHR, codified at 40 CFR
51.308,\3\ on July 1, 1999. (64 FR 35714, July 1, 1999). These Regional
Haze regulations are a central component of the EPA's comprehensive
visibility protection program for Class I Areas.
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\2\ Areas statutorily designated as mandatory Class I Federal
areas consist of national parks exceeding 6,000 acres, wilderness
areas and national memorial parks exceeding 5,000 acres, and all
international parks that were in existence on August 7, 1977. CAA
section 162(a). There are 156 mandatory Class I areas. The list of
areas to which the requirements of the visibility protection program
apply is in 40 CFR part 81, subpart D.
\3\ In addition to the generally applicable regional haze
provisions at 40 CFR 51.308, the EPA also promulgated regulations
specific to addressing regional haze visibility impairment in Class
I areas on the Colorado Plateau at 40 CFR 51.309. The latter
regulations are applicable only for specific jurisdictions' regional
haze plans submitted no later than December 17, 2007, and thus are
not relevant here.
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Regional Haze is visibility impairment that is produced by a
multitude of anthropogenic sources and activities which are located
across a broad geographic area and that emit pollutants that impair
visibility. Visibility impairing pollutants include fine and coarse PM
(e.g., sulfates, nitrates, organic carbon, elemental carbon, and soil
dust) and their precursors (e.g., SO<INF>2</INF>, NO<INF>X</INF>, and,
in some cases, VOC and NH<INF>3</INF>). Fine particle precursors react
in the atmosphere to form fine particulate matter (PM<INF>2.5</INF>),
which impairs visibility by scattering and absorbing light. Visibility
impairment reduces the perception of clarity and color, as well as
visible distance.\4\
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\4\ There are several ways to measure the amount of visibility
impairment, i.e., haze. One such measurement is the deciview, which
is the principal metric used by the RHR. Under many circumstances, a
change in one deciview will be perceived by the human eye to be the
same on both clear and hazy days. The deciview is unitless. It is
proportional to the logarithm of the atmospheric extinction of
light, which is the perceived dimming of light due to its being
scattered and absorbed as it passes through the atmosphere.
Atmospheric light extinction (b\ext\) is a metric used to for
expressing visibility and is measured in inverse megameters (Mm-1).
The EPA's Guidance on Regional Haze State Implementation Plans for
the Second Implementation Period (``2019 Guidance'') offers the
flexibility for the use of light extinction in certain cases. Light
extinction can be simpler to use in calculations than deciviews,
since it is not a logarithmic function. See, e.g., 2019 Guidance at
16, 19, <a href="https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period">https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period</a>, The EPA Office of
Air Quality Planning and Standards, Research Triangle Park (August
20, 2019). The formula for the deciview is 10 ln (b\ext\)/10 Mm-1).
40 CFR 51.301.
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To address Regional Haze visibility impairment, the 1999 RHR
established an iterative planning process that requires both states in
which Class I areas are located and states ``the emissions from which
may reasonably be anticipated to cause or contribute to any impairment
of visibility'' in a Class I Area to periodically submit SIP revisions
to address such impairment. CAA section 169A(b)(2); \5\ see also 40 CFR
51.308(b), (f) (establishing submission dates for iterative Regional
Haze SIP revisions); (64 FR 35714 at 35768, July 1, 1999). Under the
CAA, each SIP submission must contain ``a long-term (ten to fifteen
years) strategy for making reasonable progress toward meeting the
national goal,'' CAA section 169A(b)(2)(B); the initial round of SIP
submissions also had to address the statutory requirement that certain
older, larger sources of visibility impairing pollutants install and
operate the best available retrofit technology (BART). CAA section
169A(b)(2)(A); 40 CFR 51.308(d), (e). States' first Regional Haze SIPs
were due by December 17, 2007, 40 CFR 51.308(b), with subsequent SIP
submissions containing updated long-term strategies originally due July
31, 2018, and every ten years thereafter. (64 FR 35714 at 35768, July
1, 1999). The EPA established in the 1999 RHR that all states either
have Class I Areas within their borders or ``contain sources whose
emissions are reasonably anticipated to contribute to Regional Haze in
a Class I Area''; therefore, all states must submit Regional Haze
SIPs.\6\ Id. at 35721.
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\5\ The RHR expresses the statutory requirement for states to
submit plans addressing out-of-state class I areas by providing that
states must address visibility impairment ``in each mandatory Class
I Federal area located outside the State that may be affected by
emissions from within the State.'' 40 CFR 51.308(d), (f).
\6\ In addition to each of the fifty states, the EPA also
concluded that the Virgin Islands and District of Columbia must also
submit regional haze SIPs because they either contain a Class I area
or contain sources whose emissions are reasonably anticipated to
contribute regional haze in a Class I area. See 40 CFR 51.300(b),
(d)(3).
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Much of the focus in the first implementation period of the
Regional Haze program, which ran from 2007 through 2018, was on
satisfying states' BART obligations. First implementation period SIPs
were additionally required to contain long-term strategies for making
reasonable progress toward the national visibility goal, of which BART
is one component. The core required elements for the first
implementation
[[Page 55142]]
period SIPs (other than BART) are laid out in 40 CFR 51.308(d). Those
provisions required that states containing Class I Areas establish
reasonable progress goals (RPGs) that are measured in deciviews and
reflect the anticipated visibility conditions at the end of the
implementation period including from implementation of states' long-
term strategies. The first planning period RPGs were required to
provide for an improvement in visibility for the most impaired days
over the period of the implementation plan and ensure no degradation in
visibility for the least impaired days over the same period. In
establishing the RPGs for any Class I Area in a state, the state was
required to consider four statutory factors: the costs of compliance,
the time necessary for compliance, the energy and non-air quality
environmental impacts of compliance, and the remaining useful life of
any potentially affected sources. CAA section 169A(g)(1); 40 CFR
51.308(d)(1).
States were also required to calculate baseline (using the five
year period of 2000-2004) and natural visibility conditions (i.e.,
visibility conditions without anthropogenic visibility impairment) for
each Class I Area, and to calculate the linear rate of progress needed
to attain natural visibility conditions, assuming a starting point of
baseline visibility conditions in 2004 and ending with natural
conditions in 2064. This linear interpolation is known as the uniform
rate of progress (URP) and is used as a tracking metric to help states
assess the amount of progress they are making towards the national
visibility goal over time in each Class I Area.\7\ 40 CFR
51.308(d)(1)(i)(B), (d)(2). The 1999 RHR also provided that States'
long-term strategies must include the ``enforceable emissions
limitations, compliance, schedules, and other measures as necessary to
achieve the reasonable progress goals.'' 40 CFR 51.308(d)(3). In
establishing their long-term strategies, states are required to consult
with other states that also contribute to visibility impairment in a
given Class I Area and include all measures necessary to obtain their
shares of the emission reductions needed to meet the RPGs. 40 CFR
51.308(d)(3)(i) and (ii). Section 51.308(d) also contains seven
additional factors states must consider in formulating their long-term
strategies, 40 CFR 51.308(d)(3)(v), as well as provisions governing
monitoring and other implementation plan requirements. 40 CFR
51.308(d)(4). Finally, the 1999 RHR required states to submit periodic
progress reports--SIP revisions due every five years that contain
information on states' implementation of their Regional Haze plans and
an assessment of whether anything additional is needed to make
reasonable progress, see 40 CFR 51.308(g), (h)--and to consult with the
Federal Land Manager(s) \8\ (FLMs) responsible for each Class I area
according to the requirements in CAA section 169A(d) and 40 CFR
51.308(i).
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\7\ The EPA established the URP framework in the 1999 RHR to
provide ``an equitable analytical approach'' to assessing the rate
of visibility improvement at Class I areas across the country. The
start point for the URP analysis is 2004 and the endpoint was
calculated based on the amount of visibility improvement that was
anticipated to result from implementation of existing CAA programs
over the period from the mid-1990s to approximately 2005. Assuming
this rate of progress would continue into the future, the EPA
determined that natural visibility conditions would be reached in 60
years, or 2064 (60 years from the baseline starting point of 2004).
However, the EPA did not establish 2064 as the year by which the
national goal must be reached. 64 FR at 35731-32. That is, the URP
and the 2064 date are not enforceable targets, but are rather tools
that ``allow for analytical comparisons between the rate of progress
that would be achieved by the state's chosen set of control measures
and the URP.'' (82 FR 3078, 3084, January 10, 2017).
\8\ The EPA's regulations define ``Federal Land Manager'' as
``the Secretary of the department with authority over the Federal
Class I area (or the Secretary's designee) or, with respect to
Roosevelt-Campobello International Park, the Chairman of the
Roosevelt-Campobello International Park Commission.'' 40 CFR 51.301.
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On January 10, 2017, the EPA promulgated revisions to the RHR, (82
FR 3078, January 10, 2017), that apply for the second and subsequent
implementation periods. The 2017 rulemaking made several changes to the
requirements for Regional Haze SIPs to clarify States' obligations and
streamline certain Regional Haze requirements. The revisions to the
Regional Haze program for the second and subsequent implementation
periods focused on the requirement that States' SIPs contain long-term
strategies for making reasonable progress towards the national
visibility goal. The reasonable progress requirements as revised in the
2017 rulemaking (referred to here as the 2017 RHR Revisions) are
codified at 40 CFR 51.308(f). Among other changes, the 2017 RHR
Revisions adjusted the deadline for States to submit their second
implementation period SIPs from July 31, 2018, to July 31, 2021,
clarified the order of analysis and the relationship between RPGs and
the long-term strategy, and focused on making visibility improvements
on the days with the most anthropogenic visibility impairment, as
opposed to the days with the most visibility impairment overall. The
EPA also revised requirements of the visibility protection program
related to periodic progress reports and FLM consultation. The specific
requirements applicable to second implementation period Regional Haze
SIP submissions are addressed in detail below.
The EPA provided guidance to the states for their second
implementation period SIP submissions in the preamble to the 2017 RHR
Revisions as well as in subsequent, stand-alone guidance documents. In
August 2019, the EPA issued ``Guidance on Regional Haze State
Implementation Plans for the Second Implementation Period'' (``2019
Guidance'').\9\ On July 8, 2021, the EPA issued a memorandum containing
``Clarifications Regarding Regional Haze State Implementation Plans for
the Second Implementation Period'' (``2021 Clarifications Memo'').\10\
Additionally, the EPA further clarified the recommended procedures for
processing ambient visibility data and optionally adjusting the URP to
account for international anthropogenic and prescribed fire impacts in
two technical guidance documents: the December 2018 ``Technical
Guidance on Tracking Visibility Progress for the Second Implementation
Period of the Regional Haze Program'' (``2018 Visibility Tracking
Guidance''),\11\ and the June 2020 ``Recommendation for the Use of
Patched and Substituted Data and Clarification of Data Completeness for
Tracking Visibility Progress for the Second Implementation Period of
the Regional Haze Program'' and associated Technical Addendum (``2020
Data Completeness Memo'').\12\
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\9\ Guidance on Regional Haze State Implementation Plans for the
Second Implementation Period. <a href="https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period">https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period</a> The EPA Office of Air Quality Planning and
Standards, Research Triangle Park (August 20, 2019).
\10\ Clarifications Regarding Regional Haze State Implementation
Plans for the Second Implementation Period. <a href="https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf">https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf</a>. The EPA Office of Air Quality Planning and Standards,
Research Triangle Park (July 8, 2021).
\11\ Technical Guidance on Tracking Visibility Progress for the
Second Implementation Period of the Regional Haze Program. <a href="https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional">https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional</a> The EPA Office of Air
Quality Planning and Standards, Research Triangle Park. (December
20, 2018).
\12\ Recommendation for the Use of Patched and Substituted Data
and Clarification of Data Completeness for Tracking Visibility
Progress for the Second Implementation Period of the Regional Haze
Program. <a href="https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program">https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program</a> The EPA
Office of Air Quality Planning and Standards, Research Triangle Park
(June 3, 2020).
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[[Page 55143]]
As previously explained in the 2021 Clarifications Memo, the EPA
intends the second implementation period of the Regional Haze program
to secure meaningful reductions in visibility impairing pollutants that
build on the significant progress states have achieved to date. The
Agency also recognizes that analyses regarding reasonable progress are
state-specific and that, based on states' and sources' individual
circumstances, what constitutes reasonable reductions in visibility
impairing pollutants will vary from state-to-state. While there exist
many opportunities for states to leverage both ongoing and upcoming
emission reductions under other CAA programs, the Agency expects states
to undertake rigorous reasonable progress analyses that identify
further opportunities to advance the national visibility goal
consistent with the statutory and regulatory requirements. See
generally 2021 Clarifications Memo. This is consistent with Congress's
determination that a visibility protection program is needed in
addition to the CAA's National Ambient Air Quality Standards (NAAQS)
and Prevention of Significant Deterioration (PSD) programs, as further
emission reductions may be necessary to adequately protect visibility
in Class I areas throughout the country.\13\
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\13\ See, e.g., H.R. Rep No. 95-294 at 205 (``In determining how
to best remedy the growing visibility problem in these areas of
great scenic importance, the committee realizes that as a matter of
equity, the national ambient air quality standards cannot be revised
to adequately protect visibility in all areas of the country.''),
(``the mandatory class I increments of [the PSD program] do not
adequately protect visibility in class I areas'').
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B. Roles of Agencies in Addressing Regional Haze
Because the air pollutants and pollution affecting visibility in
Class I Areas can be transported over long distances, successful
implementation of the Regional Haze program requires long-term,
regional coordination among multiple jurisdictions and agencies that
have responsibility for Class I Areas and the emissions that impact
visibility in those Areas. In order to address Regional Haze, states
need to develop strategies in coordination with one another,
considering the effect of emissions from one jurisdiction on the air
quality in another. Five regional planning organizations (RPOs),\14\
which include representation from state and tribal governments, the
EPA, and FLMs, were developed in the lead-up to the first
implementation period to address Regional Haze. RPOs evaluate technical
information to better understand how emissions from State and Tribal
land impact Class I Areas across the country, pursue the development of
regional strategies to reduce emissions of PM and other pollutants
leading to Regional Haze, and help states meet the consultation
requirements of the RHR.
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\14\ RPOs are sometimes also referred to as ``multi-
jurisdictional organizations,'' or MJOs. For the purposes of this
document, the terms RPO and MJO are synonymous.
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The Central Regional Air Planning association (CenRAP), one of the
five RPOs mentioned above, that Missouri was a member of during the
first planning period, was a collaborative effort of state governments,
tribal governments, and Federal agencies established to initiate and
coordinate activities associated with the management of Regional Haze,
visibility, and other air quality issues in parts of the Great Plains,
Midwest, Southwest, and South Regions of the United States.
After the first planning period SIPs were submitted, the CenRAP was
disbanded, and the relevant regulatory entities reorganized as the
Central States Air Resources Agencies (CenSARA). CenSARA is a
collaborative effort of state governments established to initiate and
coordinate activities associated with the management of Regional Haze
and other air quality issues in parts of the Great Plains, Midwest,
Southwest, and South Regions of the United States. Member states
include: Arkansas, Iowa, Missouri, Louisiana, Kansas, Missouri,
Nebraska, Oklahoma, and Texas. Unlike CenRAP, CenSARA's voting members
are only comprised of state agency representatives. However, CenSARA
continues to include interested Tribal and Federal partners on
communications and regular meetings. The Federal partners of CenSARA
are the EPA, NPS, FWS, and FS.
IV. Requirements for Regional Haze Plans for the Second Implementation
Period
Under the CAA and the EPA's regulations, all 50 states, the
District of Columbia, and the U.S. Virgin Islands are required to
submit Regional Haze SIPs satisfying the applicable requirements for
the second implementation period of the Regional Haze program by July
31, 2021. Each state's SIP must contain a long-term strategy for making
reasonable progress toward meeting the national goal of remedying any
existing and preventing any future anthropogenic visibility impairment
in Class I areas. CAA section 169A(b)(2)(B). To this end, Sec.
51.308(f) lays out the process by which states determine what
constitutes their long-term strategies, with the order of the
requirements in Sec. 51.308(f)(1) through (f)(3) generally mirroring
the order of the steps in the reasonable progress analysis \15\ and
paragraphs (f)(4) through (f)(6) containing additional, related
requirements. Broadly speaking, a state first must identify the Class I
areas within the state and determine the Class I areas outside the
state in which visibility may be affected by emissions from the state.
These are the Class I areas that must be addressed in the state's long-
term strategy. See 40 CFR 51.308(f) and (f)(2). For each Class I area
within its borders, a state must then calculate the baseline, current,
and natural visibility conditions for that area, as well as the
visibility improvement made to date and the URP. See 40 CFR
51.308(f)(1). Each state having a Class I area and/or emissions that
may affect visibility in a Class I area must then develop a long-term
strategy that includes the enforceable emission limitations, compliance
schedules, and other measures that are necessary to make reasonable
progress in such areas. A reasonable progress determination is based on
applying the four factors in CAA section 169A(g)(1) to sources of
visibility-impairing pollutants that the state has selected to assess
for controls for the second implementation period. Additionally, as
further explained below, the RHR at 40 CFR 51.3108(f)(2)(iv) separately
provides five ``additional factors'' \16\ that states must consider in
developing their long-term strategies. See 40 CFR 51.308(f)(2). A state
evaluates potential emission reduction measures for those selected
sources and determines which are necessary to make reasonable progress
using the four statutory factors. Those measures are then incorporated
into the state's long-term strategy. After a state has developed its
long-term strategy, it then establishes RPGs for each Class I area
within its borders by modeling the visibility impacts of all reasonable
progress controls at the end of the second implementation period, i.e.,
in 2028, as well as the impacts of other requirements of the CAA. The
RPGs include reasonable progress controls not only for sources in the
state in which the Class I area is located, but also for sources in
other states that contribute to
[[Page 55144]]
visibility impairment in that area. The RPGs are then compared to the
baseline visibility conditions and the URP to ensure that progress is
being made towards the statutory goal of preventing any future and
remedying any existing anthropogenic visibility impairment in Class I
areas. 40 CFR 51.308(f)(2)-(3).
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\15\ The EPA explained in the 2017 RHR Revisions that we were
adopting new regulatory language in 40 CFR 51.308(f) that, unlike
the structure in 40 CFR 51.308(d), ``tracked the actual planning
sequence.'' (82 FR 3078 at 3091, January 10, 2017).
\16\ The five ``additional factors'' for consideration in
section 51.308(f)(2)(iv) are distinct from the four factors listed
in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states
must consider and apply to sources in determining reasonable
progress.
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In addition to satisfying the requirements at 40 CFR 51.308(f)
related to reasonable progress, the Regional Haze SIP revisions for the
second implementation period must address the requirements in Sec.
51.308(g)(1) through (5) pertaining to periodic reports describing
progress towards the RPGs, 40 CFR 51.308(f)(5), as well as requirements
for FLM consultation that apply to all visibility protection SIPs and
SIP revisions. 40 CFR 51.308(i).
A state must submit its Regional Haze SIP and subsequent SIP
revisions to the EPA according to the requirements applicable to all
SIP revisions under the CAA and the EPA's regulations. See CAA section
169(b)(2); CAA section 110(a). Upon EPA approval, a SIP is enforceable
by the Agency and the public under the CAA. If the EPA finds that a
state fails to make a required SIP revision, or if the EPA finds that a
state's SIP is incomplete or if disapproves the SIP, the Agency must
promulgate a Federal Implementation Plan (FIP) that satisfies the
applicable requirements. CAA section 110(c)(1).
A. Identification of Class I Areas
The first step in developing a Regional Haze SIP is for a state to
determine which Class I areas, in addition to those within its borders,
``may be affected'' by emissions from within the state. In the 1999
RHR, the EPA determined that all states contribute to visibility
impairment in at least one Class I area, 64 FR 35714 at 35720 through
35722, and explained that the statute and regulations lay out an
``extremely low triggering threshold'' for determining ``whether States
should be required to engage in air quality planning and analysis as a
prerequisite to determining the need for control of emissions from
sources within their State.'' Id. at 35721.
A state must determine which Class I areas must be addressed by its
SIP by evaluating the total emissions of visibility impairing
pollutants from all sources within the state. While the RHR does not
require this evaluation to be conducted in any particular manner, the
EPA's 2019 Guidance provides recommendations for how such an assessment
might be accomplished, including by, where appropriate, using the
determinations previously made for the first implementation period.
2019 Guidance at 8-9. In addition, the determination of which Class I
areas may be affected by a state's emissions is subject to the
requirement in 40 CFR 51.308(f)(2)(iii) to ``document the technical
basis, including modeling, monitoring, cost, engineering, and emissions
information, on which the State is relying to determine the emission
reduction measures that are necessary to make reasonable progress in
each mandatory Class I Federal area it affects.''
B. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
As part of assessing whether a SIP submission for the second
implementation period is providing for reasonable progress towards the
national visibility goal, the RHR contains requirements in Sec.
51.308(f)(1) related to tracking visibility improvement over time. The
requirements of this subsection apply only to states having Class I
areas within their borders; the required calculations must be made for
each such Class I area. The EPA's 2018 Visibility Tracking Guidance
\17\ provides recommendations to assist states in satisfying their
obligations under Sec. 51.308(f)(1); specifically, in developing
information on baseline, current, and natural visibility conditions,
and in making optional adjustments to the URP to account for the
impacts of international anthropogenic emissions and prescribed fires.
See 82 FR 3078 at 3103 through 3105, January 10, 2017.
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\17\ The 2018 Visibility Tracking Guidance references and relies
on parts of the 2003 Tracking Guidance: ``Guidance for Tracking
Progress Under the RHR,'' which can be found at <a href="https://www3.epa.gov/ttnamti1/files/ambient/visible/tracking.pdf">https://www3.epa.gov/ttnamti1/files/ambient/visible/tracking.pdf</a>.
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The RHR requires tracking of visibility conditions on two sets of
days: the clearest and the most impaired days. Visibility conditions
for both sets of days are expressed as the average deciview index for
the relevant five-year period (the period representing baseline or
current visibility conditions). The RHR provides that the relevant sets
of days for visibility tracking purposes are the 20% clearest (the 20%
of monitored days in a calendar year with the lowest values of the
deciview index) and 20% most impaired days (the 20% of monitored days
in a calendar year with the highest amounts of anthropogenic visibility
impairment).\18\ 40 CFR 51.301. A state must calculate visibility
conditions for both the 20% clearest and 20% most impaired days for the
baseline period of 2000-2004 and the most recent five-year period for
which visibility monitoring data are available (representing current
visibility conditions). 40 CFR 51.308(f)(1)(i) and (iii). States must
also calculate natural visibility conditions for the clearest and most
impaired days,\19\ by estimating the conditions that would exist on
those two sets of days absent anthropogenic visibility impairment. 40
CFR 51.308(f)(1)(ii). Using all these data, states must then calculate,
for each Class I area, the amount of progress made since the baseline
period (2000-2004) and how much improvement is left to achieve in order
to reach natural visibility conditions.
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\18\ This publication also refers to the 20% clearest and 20%
most anthropogenically impaired days as the ``clearest'' and ``most
impaired'' or ``most anthropogenically impaired'' days,
respectively.
\19\ The RHR at 40 CFR 51.308(f)(1)(ii) contains an error
related to the requirement for calculating two sets of natural
conditions values. The rule says ``most impaired days or the
clearest days'' where it should say ``most impaired days and
clearest days.'' This is an error that was intended to be corrected
in the 2017 RHR Revisions but did not get corrected in the final
rule language. This is supported by the preamble text at 82 FR 3078
at 3098, January 10, 2017: ``In the final version of 40 CFR
51.308(f)(1)(ii), an occurrence of ``or'' has been corrected to
``and'' to indicate that natural visibility conditions for both the
most impaired days and the clearest days must be based on available
monitoring information.''
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Using the data for the set of most impaired days only, states must
plot a line between visibility conditions in the baseline period and
natural visibility conditions for each Class I area to determine the
URP--the amount of visibility improvement, measured in deciviews, that
would need to be achieved during each implementation period in order to
achieve natural visibility conditions by the end of 2064. The URP is
used in later steps of the reasonable progress analysis for
informational purposes and to provide a non-enforceable benchmark
against which to assess a Class I area's rate of visibility
improvement.\20\ Additionally, in the 2017 RHR Revisions, the EPA
provided states the option of proposing to adjust the endpoint of the
URP to account for impacts of anthropogenic sources outside the United
States and/or impacts of certain types of wildland prescribed fires.
These adjustments, which must be approved by the EPA, are intended to
avoid any perception that states should compensate for impacts from
international anthropogenic sources and to give states the flexibility
to determine that limiting the use of wildland-prescribed fire is
[[Page 55145]]
not necessary for reasonable progress. 82 FR 3078 at 3107 footnote 116,
January 10, 2017.
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\20\ Being on or below the URP is not a ``safe harbor''; i.e.,
achieving the URP does not mean that a Class I area is making
``reasonable progress'' and does not relieve a state from using the
four statutory factors to determine what level of control is needed
to achieve such progress. See, e.g., 82 FR 3078 at 3093, January 10,
2017.
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The EPA's 2018 Visibility Tracking Guidance can be used to help
satisfy the 40 CFR 51.308(f)(1) requirements, including in developing
information on baseline, current, and natural visibility conditions,
and in making optional adjustments to the URP. In addition, the 2020
Data Completeness Memo provides recommendations on the data
completeness language referenced in Sec. 51.308(f)(1)(i) and provides
updated natural conditions estimates for each Class I area.
C. Long-Term Strategy for Regional Haze
The core component of a Regional Haze SIP submission is a long-term
strategy that addresses Regional Haze in each Class I area within a
state's borders and each Class I area that may be affected by emissions
from the state. The long-term strategy ``must include the enforceable
emissions limitations, compliance schedules, and other measures that
are necessary to make reasonable progress, as determined pursuant to
paragraphs (f)(2)(i) through (iv).'' 40 CFR 51.308(f)(2). The amount of
progress that is ``reasonable progress'' is based on applying the four
statutory factors in CAA section 169A(g)(1) in an evaluation of
potential control options for sources of visibility impairing
pollutants, which is referred to as a ``four-factor'' analysis. The
outcome of that analysis is the emission reduction measures that a
particular source or group of sources needs to implement in order to
make reasonable progress towards the national visibility goal. See 40
CFR 51.308(f)(2)(i). Emission reduction measures that are necessary to
make reasonable progress may be either new, additional control measures
for a source, or they may be the existing emission reduction measures
that a source is already implementing. See 2019 Guidance at 43; 2021
Clarifications Memo at 8-10. Such measures must be represented by
``enforceable emissions limitations, compliance schedules, and other
measures'' (i.e., any additional compliance tools) in a state's long-
term strategy in its SIP. 40 CFR 51.308(f)(2).
Section 51.308(f)(2)(i) provides the requirements for the four-
factor analysis. The first step of this analysis entails selecting the
sources to be evaluated for emission reduction measures; to this end,
the RHR requires states to consider ``major and minor stationary
sources or groups of sources, mobile sources, and area sources'' of
visibility impairing pollutants for potential four-factor control
analysis. 40 CFR 51.308(f)(2)(i). A threshold question at this step is
which visibility impairing pollutants will be analyzed. As the EPA
previously explained, consistent with the first implementation period,
the EPA generally expects that each state will analyze at least
SO<INF>2</INF> and NO<INF>X</INF> in selecting sources and determining
control measures. See 2019 Guidance at 12, 2021 Clarifications Memo at
4. A state that chooses not to consider at least these two pollutants
should demonstrate why such consideration would be unreasonable. 2021
Clarifications Memo at 4.
While states have the option to analyze all sources, the 2019
Guidance explains that ``an analysis of control measures is not
required for every source in each implementation period,'' and that
``[s]electing a set of sources for analysis of control measures in each
implementation period is . . . consistent with the RHR, which sets up
an iterative planning process and anticipates that a state may not need
to analyze control measures for all its sources in a given SIP
revision.'' 2019 Guidance at 9. However, given that source selection is
the basis of all subsequent control determinations, a reasonable source
selection process ``should be designed and conducted to ensure that
source selection results in a set of pollutants and sources the
evaluation of which has the potential to meaningfully reduce their
contributions to visibility impairment.'' 2021 Clarifications Memo at
3.
The EPA explained in the 2021 Clarifications Memo that each state
has an obligation to submit a long-term strategy that addresses the
Regional Haze visibility impairment that results from emissions from
within that state. Thus, source selection should focus on the in-state
contribution to visibility impairment and be designed to capture a
meaningful portion of the state's total contribution to visibility
impairment in Class I areas. A state should not decline to select its
largest in-state sources on the basis that there are even larger out-
of-state contributors. 2021 Clarifications Memo at 4.\21\
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\21\ Similarly, in responding to comments on the 2017 RHR
Revisions, the EPA explained that ``[a] state should not fail to
address its many relatively low-impact sources merely because it
only has such sources and another state has even more low-impact
sources and/or some high impact sources.'' Responses to Comments on
Protection of Visibility: Amendments to Requirements for State
Plans; Proposed Rule. Docket Document ID: EPA-HQ-OAR-2015-0531-0635
at pages 87-88.
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Thus, while states have discretion to choose any source selection
methodology that is reasonable, whatever choices they make should be
reasonably explained. To this end, 40 CFR 51.308(f)(2)(i) requires that
a state's SIP submission include ``a description of the criteria it
used to determine which sources or groups of sources it evaluated.''
The technical basis for source selection, which may include methods for
quantifying potential visibility impacts such as emissions divided by
distance metrics, trajectory analyses, residence time analyses, and/or
photochemical modeling, must also be appropriately documented, as
required by 40 CFR 51.308(f)(2)(iii).
Once a state has selected the set of sources, the next step is to
determine the emissions reduction measures for those sources that are
necessary to make reasonable progress for the second implementation
period.\22\ This is accomplished by considering the Four Factors--``the
costs of compliance, the time necessary for compliance, and the energy
and nonair quality environmental impacts of compliance, and the
remaining useful life of any existing source subject to such
requirements.'' CAA section 169A(g)(1). The EPA has explained that the
four-factor analysis is an assessment of potential emission reduction
measures (i.e., control options) for sources; ``use of the terms
`compliance' and `subject to such requirements' in section 169A(g)(1)
strongly indicates that Congress intended the relevant determination to
be the requirements with which sources would have to comply in order to
satisfy the CAA's reasonable progress mandate.'' 82 FR 3078 at 3091,
January 10, 2017. Thus, for each source it has selected for four-factor
analysis,\23\ a state
[[Page 55146]]
must consider a ``meaningful set'' of technically feasible control
options for reducing emissions of visibility impairing pollutants. Id.
at 3088. The 2019 Guidance provides that ``[a] state must reasonably
pick and justify the measures that it will consider, recognizing that
there is no statutory or regulatory requirement to consider all
technically feasible measures or any particular measures. A range of
technically feasible measures available to reduce emissions would be
one way to justify a reasonable set.'' 2019 Guidance at 29.
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\22\ The CAA provides that, ``[i]n determining reasonable
progress there shall be taken into consideration'' the four
statutory factors. CAA section 169A(g)(1). However, in addition to
four-factor analyses for selected sources, groups of sources, or
source categories, a state may also consider additional emission
reduction measures for inclusion in its long-term strategy, e.g.,
from other newly adopted, on-the-books, or on-the-way rules and
measures for sources not selected for four-factor analysis for the
second planning period.
\23\ ``Each source'' or ``particular source'' is used here as
shorthand. While a source-specific analysis is one way of applying
the Four Factors, neither the statute nor the RHR requires states to
evaluate individual sources. Rather, states have ``the flexibility
to conduct four-factor analyses for specific sources, groups of
sources or even entire source categories, depending on state policy
preferences and the specific circumstances of each state.'' 82 FR
3078 at 3088, January 10, 2017. However, not all approaches to
grouping sources for four-factor analysis are necessarily
reasonable; the reasonableness of grouping sources in any particular
instance will depend on the circumstances and the manner in which
grouping is conducted. If it is feasible to establish and enforce
different requirements for sources or subgroups of sources, and if
relevant factors can be quantified for those sources or subgroups,
then states should make a separate reasonable progress determination
for each source or subgroup. 2021 Clarifications Memo at 7-8.
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The EPA's 2021 Clarifications Memo provides further guidance on
what constitutes a reasonable set of control options for consideration:
``A reasonable four-factor analysis will consider the full range of
potentially reasonable options for reducing emissions.'' 2021
Clarifications Memo at 7. In addition to add-on controls and other
retrofits (i.e., new emission reduction measures for sources), the EPA
explained that states should generally analyze efficiency improvements
for sources' existing measures as control options in their four-factor
analyses, as in many cases such improvements are reasonable given that
they typically involve only additional operation and maintenance costs.
Additionally, the 2021 Clarifications Memo provides that states that
have assumed a higher emission rate than a source has achieved or could
potentially achieve using its existing measures should also consider
lower emission rates as potential control options. That is, a state
should consider a source's recent actual and projected emission rates
to determine if it could reasonably attain lower emission rates with
its existing measures. If so, the state should analyze the lower
emission rate as a control option for reducing emissions. 2021
Clarifications Memo at 7. The EPA's recommendations to analyze
potential efficiency improvements and achievable lower emission rates
apply to both sources that have been selected for four-factor analysis
and those that have forgone a four-factor analysis on the basis of
existing ``effective controls.'' See 2021 Clarifications Memo at 5, 10.
After identifying a reasonable set of potential control options for
the sources it has selected, a state then collects information on the
Four Factors with regard to each option identified. The EPA has also
explained that, in addition to the four statutory factors, states have
flexibility under the CAA and RHR to reasonably consider visibility
benefits as an additional factor alongside the four statutory
factors.\24\ The 2019 Guidance provides recommendations for the types
of information that can be used to characterize the Four Factors (with
or without visibility), as well as ways in which states might
reasonably consider and balance that information to determine which of
the potential control options is necessary to make reasonable progress.
See 2019 Guidance at 30-36. The 2021 Clarifications Memo contains
further guidance on how states can reasonably consider modeled
visibility impacts or benefits in the context of a four-factor
analysis. 2021 Clarifications Memo at 12-13, 14-15. Specifically, the
EPA explained that while visibility can reasonably be used when
comparing and choosing between multiple reasonable control options, it
should not be used to summarily reject controls that are reasonable
given the four statutory factors. 2021 Clarifications Memo at 13.
Ultimately, while states have discretion to reasonably weigh the
factors and to determine what level of control is needed, Sec.
51.308(f)(2)(i) provides that a state ``must include in its
implementation plan a description of . . . how the Four Factors were
taken into consideration in selecting the measure for inclusion in its
long-term strategy.''
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\24\ See, e.g., Responses to Comments on Protection of
Visibility: Amendments to Requirements for State Plans; Proposed
Rule (81 FR 26942, May 4, 2016), Docket Number EPA-HQ-OAR-2015-0531,
U.S. Environmental Protection Agency at 186; 2019 Guidance at 36-37.
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As explained above, Sec. 51.308(f)(2)(i) requires states to
determine the emission reduction measures for sources that are
necessary to make reasonable progress by considering the Four Factors.
Pursuant to Sec. 51.308(f)(2), measures that are necessary to make
reasonable progress towards the national visibility goal must be
included in a state's long-term strategy and in its SIP.\25\ If the
outcome of a four-factor analysis is a new, additional emission
reduction measure for a source, that new measure is necessary to make
reasonable progress towards remedying existing anthropogenic visibility
impairment and must be included in the SIP. If the outcome of a four-
factor analysis is that no new measures are reasonable for a source,
continued implementation of the source's existing measures is generally
necessary to prevent future emission increases and thus to make
reasonable progress towards the second part of the national visibility
goal: preventing future anthropogenic visibility impairment. See CAA
section 169A(a)(1). That is, when the result of a four-factor analysis
is that no new measures are necessary to make reasonable progress, the
source's existing measures are generally necessary to make reasonable
progress and must be included in the SIP. However, there may be
circumstances in which a state can demonstrate that a source's existing
measures are not necessary to make reasonable progress. Specifically,
if a state can demonstrate that a source will continue to implement its
existing measures and will not increase its emission rate, it may not
be necessary to have those measures in the long-term strategy in order
to prevent future emission increases and future visibility impairment.
The EPA's 2021 Clarifications Memo provides further explanation and
guidance on how states may demonstrate that a source's existing
measures are not necessary to make reasonable progress. See 2021
Clarifications Memo at 8-10. If the state can make such a
demonstration, it need not include a source's existing measures in the
long-term strategy or its SIP.
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\25\ States may choose to, but are not required to, include
measures in their long-term strategies beyond just the emission
reduction measures that are necessary for reasonable progress. See
2021 Clarifications Memo at 16. For example, states with smoke
management programs may choose to submit their smoke management
plans to the EPA for inclusion in their SIPs but are not required to
do so. See, e.g., 82 FR 3078 at 3108 and 3109, January 10, 2017
(requirement to consider smoke management practices and smoke
management programs under 40 CFR 51.308(f)(2)(iv) does not require
states to adopt such practices or programs into their SIPs, although
they may elect to do so).
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As with source selection, the characterization of information on
each of the factors is also subject to the documentation requirement in
Sec. 51.308(f)(2)(iii). The reasonable progress analysis, including
source selection, information gathering, characterization of the four
statutory factors (and potentially visibility), balancing of the Four
Factors, and selection of the emission reduction measures that
represent reasonable progress, is a technically complex exercise, but
also a flexible one that provides states with bounded discretion to
design and implement approaches appropriate to their circumstances.
Given this flexibility, Sec. 51.308(f)(2)(iii) plays an important
function in requiring a state to document the technical basis for its
decision making so that the public and the EPA can comprehend and
evaluate the information and analysis the state relied upon to
determine what emission reduction measures must be in place to make
reasonable progress. The technical documentation must include the
modeling, monitoring, cost, engineering,
[[Page 55147]]
and emissions information on which the state relied to determine the
measures necessary to make reasonable progress. This documentation
requirement can be met through the provision of and reliance on
technical analyses developed through a regional planning process, so
long as that process and its output has been approved by all state
participants. In addition to the explicit regulatory requirement to
document the technical basis of their reasonable progress
determinations, states are also subject to the general principle that
those determinations must be reasonably moored to the statute.\26\ That
is, a state's decisions about the emission reduction measures that are
necessary to make reasonable progress must be consistent with the
statutory goal of remedying existing and preventing future visibility
impairment.
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\26\ See Arizona ex rel. Darwin v. U.S. EPA, 815 F.3d 519, 531
(9th Cir. 2016); Nebraska v. U.S. EPA, 812 F.3d 662, 668 (8th Cir.
2016); North Dakota v. EPA, 730 F.3d 750, 761 (8th Cir. 2013);
Oklahoma v. EPA, 723 F.3d 1201, 1206, 1208-10 (10th Cir. 2013); cf.
also Nat'l Parks Conservation Ass'n v. EPA, 803 F.3d 151, 165 (3d
Cir. 2015); Alaska Dep't of Envtl. Conservation v. EPA, 540 U.S.
461, 485, 490 (2004).
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The four statutory factors (and potentially visibility) are used to
determine what emission reduction measures for selected sources must be
included in a state's long-term strategy for making reasonable
progress. Additionally, the RHR at 40 CFR 51.3108(f)(2)(iv) separately
provides five ``additional factors'' \27\ that states must consider in
developing their long-term strategies: (1) emission reductions due to
ongoing air pollution control programs, including measures to address
reasonably attributable visibility impairment; (2) measures to reduce
the impacts of construction activities; (3) source retirement and
replacement schedules; (4) basic smoke management practices for
prescribed fire used for agricultural and wildland vegetation
management purposes and smoke management programs; and (5) the
anticipated net effect on visibility due to projected changes in point,
area, and mobile source emissions over the period addressed by the
long-term strategy. The 2019 Guidance provides that a state may satisfy
this requirement by considering these additional factors in the process
of selecting sources for four-factor analysis, when performing that
analysis, or both, and that not every one of the additional factors
needs to be considered at the same stage of the process. See 2019
Guidance at 21. The EPA provided further guidance on the five
additional factors in the 2021 Clarifications Memo, explaining that a
state should generally not reject cost-effective and otherwise
reasonable controls merely because there have been emission reductions
since the first planning period owing to other ongoing air pollution
control programs or merely because visibility is otherwise projected to
improve at Class I areas. Additionally, states generally should not
rely on these additional factors to summarily assert that the state has
already made sufficient progress and, therefore, no sources need to be
selected or no new controls are needed regardless of the outcome of
four-factor analyses. 2021 Clarifications Memo at 13.
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\27\ The five ``additional factors'' for consideration in
section 51.308(f)(2)(iv) are distinct from the Four Factors listed
in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states
must consider and apply to sources in determining reasonable
progress.
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Because the air pollution that causes Regional Haze crosses state
boundaries, Sec. 51.308(f)(2)(ii) requires a state to consult with
other states that also have emissions that are reasonably anticipated
to contribute to visibility impairment in a given Class I area.
Consultation allows for each state that impacts visibility in an area
to share whatever technical information, analyses, and control
determinations may be necessary to develop coordinated emission
management strategies. This coordination may be managed through inter-
and intra-RPO consultation and the development of regional emissions
strategies; additional consultations between states outside of RPO
processes may also occur. If a state, pursuant to consultation, agrees
that certain measures (e.g., a certain emission limitation) are
necessary to make reasonable progress at a Class I area, it must
include those measures in its SIP. 40 CFR 51.308(f)(2)(ii)(A).
Additionally, the RHR requires that states that contribute to
visibility impairment at the same Class I area consider the emission
reduction measures the other contributing states have identified as
being necessary to make reasonable progress for their own sources. 40
CFR 51.308(f)(2)(ii)(B). If a state has been asked to consider or adopt
certain emission reduction measures, but ultimately determines those
measures are not necessary to make reasonable progress, that state must
document in its SIP the actions taken to resolve the disagreement. 40
CFR 51.308(f)(2)(ii)(C). The EPA will consider the technical
information and explanations presented by the submitting state and the
state with which it disagrees when considering whether to approve the
state's SIP. See id.; 2019 Guidance at 53. Under all circumstances, a
state must document in its SIP submission all substantive consultations
with other contributing states. 40 CFR 51.308(f)(2)(ii)(C).
D. Reasonable Progress Goals
Reasonable progress goals ``measure the progress that is projected
to be achieved by the control measures states have determined are
necessary to make reasonable progress based on a four-factor
analysis.'' 82 FR 3078 at 3091, January 10, 2017. Their primary purpose
is to assist the public and the EPA in assessing the reasonableness of
states' long-term strategies for making reasonable progress towards the
national visibility goal. See 40 CFR 51.308(f)(3)(iii) and (iv). States
in which Class I areas are located must establish two RPGs, both in
deciviews--one representing visibility conditions on the clearest days
and one representing visibility on the most anthropogenically impaired
days--for each area within their borders. 40 CFR 51.308(f)(3)(i). The
two RPGs are intended to reflect the projected impacts, on the two sets
of days, of the emission reduction measures the state with the Class I
area, as well as all other contributing states, have included in their
long-term strategies for the second implementation period.\28\ The RPGs
also account for the projected impacts of implementing other CAA
requirements, including non-SIP based requirements. Because RPGs are
the modeled result of the measures in states' long-term strategies (as
well as other measures required under the CAA), they cannot be
determined before states have conducted their four-factor analyses and
determined the control measures that are necessary to make reasonable
progress. See 2021 Clarifications Memo at 6.
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\28\ RPGs are intended to reflect the projected impacts of the
measures all contributing states include in their long-term
strategies. However, due to the timing of analyses and of control
determinations by other states, other on-going emissions changes, a
particular state's RPGs may not reflect all control measures and
emissions reductions that are expected to occur by the end of the
implementation period. The 2019 Guidance provides recommendations
for addressing the timing of RPG calculations when states are
developing their long-term strategies on disparate schedules, as
well as for adjusting RPGs using a post-modeling approach. 2019
Guidance at 47-48.
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For the second implementation period, the RPGs are set for 2028.
Reasonable progress goals are not enforceable targets, 40 CFR
51.308(f)(3)(iii); rather, they ``provide a way for the states to check
the projected outcome of the [long-term strategy] against the goals for
visibility improvement.'' 2019 Guidance at 46.
[[Page 55148]]
While states are not legally obligated to achieve the visibility
conditions described in their RPGs, Sec. 51.308(f)(3)(i) requires that
``[t]he long-term strategy and the reasonable progress goals must
provide for an improvement in visibility for the most impaired days
since the baseline period and ensure no degradation in visibility for
the clearest days since the baseline period.'' Thus, states are
required to have emission reduction measures in their long-term
strategies that are projected to achieve visibility conditions on the
most impaired days that are better than the baseline period and shows
no degradation on the clearest days compared to the clearest days from
the baseline period. The baseline period for the purpose of this
comparison is the baseline visibility condition--the annual average
visibility condition for the period 2000 through 2004. See 40 CFR
51.308(f)(1)(i), 82 FR 3078 at 3097 and 3098, January 10, 2017.
So that RPGs may also serve as a metric for assessing the amount of
progress a state is making towards the national visibility goal, the
RHR requires states with Class I areas to compare the 2028 RPG for the
most impaired days to the corresponding point on the URP line
(representing visibility conditions in 2028 if visibility were to
improve at a linear rate from conditions in the baseline period of
2000-2004 to natural visibility conditions in 2064). If the most
impaired days RPG in 2028 is above the URP (i.e., if visibility
conditions are improving more slowly than the rate described by the
URP), each state that contributes to visibility impairment in the Class
I area must demonstrate, based on the four-factor analysis required
under 40 CFR 51.308(f)(2)(i), that no additional emission reduction
measures would be reasonable to include in its long-term strategy. 40
CFR 51.308(f)(3)(ii). To this end, 40 CFR 51.308(f)(3)(ii) requires
that each state contributing to visibility impairment in a Class I area
that is projected to improve more slowly than the URP provide ``a
robust demonstration, including documenting the criteria used to
determine which sources or groups [of] sources were evaluated and how
the Four Factors required by paragraph (f)(2)(i) were taken into
consideration in selecting the measures for inclusion in its long-term
strategy.'' The 2019 Guidance provides suggestions about how such a
``robust demonstration'' might be conducted. See 2019 Guidance at 50-
51.
The 2017 RHR, 2019 Guidance, and 2021 Clarifications Memo also
explain that projecting an RPG that is on or below the URP based on
only on-the-books and/or on-the-way control measures (i.e., control
measures already required or anticipated before the four-factor
analysis is conducted) is not a ``safe harbor'' from the CAA's and
RHR's requirement that all states must conduct a four-factor analysis
to determine what emission reduction measures constitute reasonable
progress. The URP is a planning metric used to gauge the amount of
progress made thus far and the amount left before reaching natural
visibility conditions. However, the URP is not based on consideration
of the four statutory factors and therefore cannot answer the question
of whether the amount of progress being made in any particular
implementation period is ``reasonable progress.'' See 82 FR 3078 at
3093, 3099 and 3100, January 10, 2017; 2019 Guidance at 22; 2021
Clarifications Memo at 15-16.
E. Monitoring Strategy and Other State Implementation Plan Requirements
Section 51.308(f)(6) requires states to have certain strategies and
elements in place for assessing and reporting on visibility. Individual
requirements under this subsection apply either to states with Class I
areas within their borders, states with no Class I areas but that are
reasonably anticipated to cause or contribute to visibility impairment
in any Class I area, or both. A state with Class I areas within its
borders must submit with its SIP revision a monitoring strategy for
measuring, characterizing, and reporting Regional Haze visibility
impairment that is representative of all Class I areas within the
state. SIP revisions for such states must also provide for the
establishment of any additional monitoring sites or equipment needed to
assess visibility conditions in Class I areas, as well as reporting of
all visibility monitoring data to the EPA at least annually. Compliance
with the monitoring strategy requirement may be met through a state's
participation in the Interagency Monitoring of Protected Visual
Environments (IMPROVE) monitoring network, which is used to measure
visibility impairment caused by air pollution at the 156 Class I areas
covered by the visibility program. 40 CFR 51.308(f)(6), (f)(6)(i), and
(f)(6)(iv). The IMPROVE monitoring data is used to determine the 20%
most anthropogenically impaired and 20% clearest sets of days every
year at each Class I area and tracks visibility impairment over time.
All states' SIPs must provide for procedures by which monitoring
data and other information are used to determine the contribution of
emissions from within the state to Regional Haze visibility impairment
in affected Class I areas. 40 CFR 51.308(f)(6)(ii) and (iii). Section
51.308(f)(6)(v) further requires that all states' SIPs provide for a
statewide inventory of emissions of pollutants that are reasonably
anticipated to cause or contribute to visibility impairment in any
Class I area; the inventory must include emissions for the most recent
year for which data are available and estimates of future projected
emissions. States must also include commitments to update their
inventories periodically. The inventories themselves do not need to be
included as elements in the SIP and are not subject to EPA review as
part of the Agency's evaluation of a SIP revision.\29\ All states' SIPs
must also provide for any other elements, including reporting,
recordkeeping, and other measures, that are necessary for states to
assess and report on visibility. 40 CFR 51.308(f)(6)(vi). Per the 2019
Guidance, a state may note in its Regional Haze SIP that its compliance
with the Air Emissions Reporting Rule (AERR) in 40 CFR part 51 subpart
A satisfies the requirement to provide for an emissions inventory for
the most recent year for which data are available. To satisfy the
requirement to provide estimates of future projected emissions, a state
may explain in its SIP how projected emissions were developed for use
in establishing RPGs for its own and nearby Class I areas.\30\
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\29\ See ``Step 8: Additional requirements for regional haze
SIPs'' in 2019 Regional Haze Guidance at 55.
\30\ Id.
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Separate from the requirements related to monitoring for Regional
Haze purposes under 40 CFR 51.308(f)(6), the RHR also contains a
requirement at Sec. 51.308(f)(4) related to any additional monitoring
that may be needed to address visibility impairment in Class I areas
from a single source or a small group of sources. This is called
``reasonably attributable visibility impairment.'' \31\ Under this
provision, if the EPA or the FLM of an affected Class I area has
advised a state that additional monitoring is needed to assess
reasonably attributable visibility impairment, the state must include
in its SIP revision for the second implementation period an appropriate
strategy for evaluating such impairment.
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\31\ The EPA's visibility protection regulations define
``reasonably attributable visibility impairment'' as ``visibility
impairment that is caused by the emission of air pollutants from
one, or a small number of sources.'' 40 CFR 51.301.
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[[Page 55149]]
F. Requirements for Periodic Reports Describing Progress Towards the
Reasonable Progress Goals
Section 51.308(f)(5) requires a state's Regional Haze SIP revision
to address the requirements of 40 CFR 51.308(g)(1) through (5) so that
the plan revision due in 2021 will serve also as a progress report
addressing the period since submission of the progress report for the
first implementation period. The Regional Haze progress report
requirement is designed to inform the public and the EPA about a
state's implementation of its existing long-term strategy and whether
such implementation is in fact resulting in the expected visibility
improvement. See 81 FR 26942, 26950 (May 4, 2016), (82 FR 3078 at 3119,
January 10, 2017). To this end, every state's SIP revision for the
second implementation period is required to describe the status of
implementation of all measures included in the state's long-term
strategy, including BART and reasonable progress emission reduction
measures from the first implementation period, and the resulting
emissions reductions. 40 CFR 51.308(g)(1) and (2).
A core component of the progress report requirements is an
assessment of changes in visibility conditions on the clearest and most
impaired days. For second implementation period progress reports, Sec.
51.308(g)(3) requires states with Class I areas within their borders to
first determine current visibility conditions for each area on the most
impaired and clearest days, 40 CFR 51.308(g)(3)(i)(B), and then to
calculate the difference between those current conditions and baseline
(2000-2004) visibility conditions in order to assess progress made to
date. See 40 CFR 51.308(g)(3)(ii)(B). States must also assess the
changes in visibility impairment for the most impaired and clearest
days since they submitted their first implementation period progress
reports. See 40 CFR 51.308 (f)(5) and (g)(3)(iii)(B). Since different
states submitted their first implementation period progress reports at
different times, the starting point for this assessment will vary state
by state.
Similarly, states must provide analyses tracking the change in
emissions of pollutants contributing to visibility impairment from all
sources and activities within the state over the period since they
submitted their first implementation period progress reports. See 40
CFR 51.308(f)(5) and (g)(4). Changes in emissions should be identified
by the type of source or activity. Section 51.308(g)(5) also addresses
changes in emissions since the period addressed by the previous
progress report and requires states' SIP revisions to include an
assessment of any significant changes in anthropogenic emissions within
or outside the state. This assessment must include an explanation of
whether these changes in emissions were anticipated and whether they
have limited or impeded progress in reducing emissions and improving
visibility relative to what the state projected based on its long-term
strategy for the first implementation period.
G. Requirements for State and Federal Land Manager Coordination
CAA section 169A(d) requires that before a state holds a public
hearing on a proposed Regional Haze SIP revision, it must consult with
the appropriate FLM or FLMs; pursuant to that consultation, the state
must include a summary of the FLMs' conclusions and recommendations in
the notice to the public. Consistent with this statutory requirement,
the RHR also requires that states ``provide the [FLM] with an
opportunity for consultation, in person and at a point early enough in
the State's policy analyses of its long-term strategy emission
reduction obligation so that information and recommendations provided
by the [FLM] can meaningfully inform the State's decisions on the long-
term strategy.'' 40 CFR 51.308(i)(2). Consultation that occurs 120 days
prior to any public hearing or public comment opportunity will be
deemed ``early enough,'' but the RHR provides that in any event the
opportunity for consultation must be provided at least 60 days before a
public hearing or comment opportunity. This consultation must include
the opportunity for the FLMs to discuss their assessment of visibility
impairment in any Class I area and their recommendations on the
development and implementation of strategies to address such
impairment. 40 CFR 51.308(i)(2). In order for the EPA to evaluate
whether FLM consultation meeting the requirements of the RHR has
occurred, the SIP submission should include documentation of the timing
and content of such consultation. The SIP revision submitted to the EPA
must also describe how the state addressed any comments provided by the
FLMs. 40 CFR 51.308(i)(3). Finally, a SIP revision must provide
procedures for continuing consultation between the state and FLMs
regarding the state's visibility protection program, including
development and review of SIP revisions, five-year progress reports,
and the implementation of other programs having the potential to
contribute to impairment of visibility in Class I areas. 40 CFR
51.308(i)(4).
V. The EPA's Evaluation of Missouri's Regional Haze Submission for the
Second Implementation Period
A. Background on Missouri's First Implementation Period SIP Submission
Missouri submitted its Regional Haze SIP for the first
implementation period to the EPA on August 5, 2009, and supplemented on
January 30, 2012. Missouri relied on the Clean Air Interstate Rule
(CAIR) to satisfy BART requirements. The EPA approved Missouri's first
implementation period Regional Haze SIP submission on June 26, 2012 (77
FR 38007, June 26, 2012).\32\ The requirements for Regional Haze SIPs
for the first implementation period are contained in 40 CFR 51.308(d)
and (e). 40 CFR 51.308(b). In July 2008, the CAIR rule was vacated by
the District of Columbia Circuit Court.\33\ In response on August 8,
2011, the EPA replaced CAIR with the Cross-State Air Pollution Rule
(CSAPR).\34\ Afterwards, the EPA promulgated the CSAPR better than BART
rule, allowing states to rely on CSAPR to satisfy BART
requirements.\35\ In that same action, the EPA issued FIPs to replace
reliance on CAIR for BART with reliance on CSAPR to satisfy BART
requirements. This action included Missouri. Pursuant to 40 CFR
51.308(g), Missouri was also required to submit a five-year progress
report as a SIP revision for the first implementation period. On August
5, 2014, Missouri submitted the required progress report to the EPA.
The EPA approved the progress report on September 29, 2015 (80 FR
58410, September 29, 2015). On July 31, 2017, Missouri submitted a SIP
revision to change their reliance on CAIR for BART to relying on CSAPR
for BART. The EPA approved this SIP revision.\36\
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\32\ The EPA's action included a limited approval as the state
relied on the EPA's Federal Implementation Plan (FIP) for the
interstate transport program to address the required best available
retrofit technology (BART) requirements for certain electric
generating units (EGUs).
\33\ North Carolina v. EPA, 531 F.3d 896 (D.C. Cir. 2008),
modified on rehearing, North Carolina v. EPA, 550 F.3d 1176, 1178
(D.C. Cir. 2008).
\34\ 76 FR 48208 August 8, 2011.
\35\ 77 FR 33642 June 7, 2012.
\36\ 81 FR 50531 September 24, 2018.
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B. Missouri's Second Implementation Period SIP Submission and the EPA's
Evaluation
In accordance with CAA sections 169A and the RHR at 40 CFR
51.308(f), (g), and (i), on August 26, 2022, Missouri submitted a
revision to Missouri's SIP to address its Regional
[[Page 55150]]
Haze obligations for the second implementation period. Missouri made
its second implementation period Regional Haze SIP submission available
for public comment from March 28, 2022, through May 5, 2022. The state
held a public hearing for the plan on April 28, 2022. Missouri received
and responded to public comments and included both the comments and
responses to those comments in their submission.
The following sections describe Missouri's SIP submission as well
as the EPA's evaluation to determine if Missouri's submission meets all
of the requirements of the CAA and RHR for the second implementation
period of the Regional Haze program.
C. Identification of Class I Areas
Section 169A(b)(2) of the CAA requires each state in which any
Class I area is located or ``the emissions from which may reasonably be
anticipated to cause or contribute to any impairment of visibility'' in
a Class I area to have a plan for making reasonable progress toward the
national visibility goal. The RHR implements this statutory requirement
at 40 CFR 51.308(f), which provides that each state's plan ``must
address Regional Haze in each mandatory Class I Federal area located
within the State and in each mandatory Class I Federal area located
outside the State that may be affected by emissions from within the
State,'' and paragraph (f)(2), which requires each state's plan to
include a long-term strategy that addresses Regional Haze in such Class
I areas.
The EPA explained in the 1999 RHR preamble that the CAA section
169A(b)(2) requirement that states submit SIPs to address visibility
impairment establishes ``an `extremely low triggering threshold' in
determining which States should submit SIPs for regional haze.'' 64 FR
35714 at 35721, July 1, 1999. In concluding that each of the contiguous
48 states and the District of Columbia meet this threshold,\37\ the EPA
relied on ``a large body of evidence demonstrat[ing] that long-range
transport of fine PM contributes to regional haze,'' id., including
modeling studies that ``preliminarily demonstrated that each State not
having a Class I area had emissions contributing to impairment in at
least one downwind Class I area.'' Id. at 35722. In addition to the
technical evidence supporting a conclusion that each state contributes
to existing visibility impairment, the EPA also explained that the
second half of the national visibility goal--preventing future
visibility impairment--requires having a framework in place to address
future growth in visibility-impairing emissions and makes it
inappropriate to ``establish criteria for excluding States or
geographic areas from consideration as potential contributors to
regional haze visibility impairment.'' Id. at 35721. Thus, the EPA
concluded that the agency's ``statutory authority and the scientific
evidence are sufficient to require all States to develop regional haze
SIPs to ensure the prevention of any future impairment of visibility,
and to conduct further analyses to determine whether additional control
measures are needed to ensure reasonable progress in remedying existing
impairment in downwind Class I areas.'' Id. at 35722. The EPA's 2017
revisions to the RHR did not disturb this conclusion. See 82 FR 3078 at
3094, January 10, 2017.
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\37\ The EPA determined that ``there is more than sufficient
evidence to support our conclusion that emissions from each of the
48 contiguous states and the District of Columba may reasonably be
anticipated to cause or contribute to visibility impairment in a
Class I area.'' 64 FR 35714 at 35721, July 1, 1999. Hawaii, Alaska,
and the U.S. Virgin Islands must also submit regional haze SIPs
because they contain Class I areas.
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Missouri contains two Class I Areas: Hercules-Glades Wilderness
Area and Mingo National Wildlife Refuge. In Missouri's Regional Haze
plan for the first planning period, submitted on August 5, 2009, and
supplemented on January 30, 2012, Missouri analyzed four Class I Areas
as potentially affected by Missouri emissions. In addition to the two
Class I Areas in Missouri, the state identified Caney Creek Wilderness
Area and Upper Buffalo Wilderness Area located in Arkansas.\38\ In
Missouri's Regional Haze plan for the second planning period, submitted
August 26, 2022, Missouri identifies nine Class I Areas: Hercules-
Glades Wilderness Area and Mingo National Wildlife Refuge in Missouri,
Upper Buffalo Wilderness Area, Arkansas, Seney National Wildlife Refuge
and Isle Royale Wilderness in Michigan, Mammoth Cave National Park,
Kentucky, Linville Gorge Wilderness Area and Shining Rock Wilderness
Area in North Carolina, and Sipsey Wilderness Area, Alabama; as
potentially affected by Missouri emissions. To make this determination,
Missouri primarily relied on the cumulative sulfate and nitrate
extinction weighted residence time (EWRT) multiplied by Q/d (emissions
divided by distance) analysis performed by a CenSARA contractor to
identify the sources with the highest estimated contributions to Class
I Areas. As further discussed in section E of this preamble, Missouri
selected sources contributing more than 1 percent to any Class I Area
for further evaluation.\39\
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\38\ ``State of Missouri Air Quality State Implementation Plan
Regional Haze, Section D, Plan Revision'' Page 47, submitted
November 9, 2009. Available in Docket: EPA-R07-OAR-2012-0153.
\39\ See Table 36, starting on page 103 of Missouri's August
2022 submittal.
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CenSARA performed technical analyses to help assess source and
state-level contributions to visibility impairment and the need for
interstate consultation. CenSARA's analyses relied on a back-trajectory
model combined with air quality measurement data and emission
inventories to identify the geographic areas and emission sources with
a high probability of contributing to anthropogenically impaired
visibility at Class I areas within CenSARA and nearby states. For the
EWRT multiplied by Q/d analysis, back trajectory residence times were
first calculated by summing the amount of time trajectories reside in a
specific geographic area (e.g., modeling grid cell). The trajectory
residence times were then weighted by sulfate and nitrate extinction
coefficients to account for the varying contributions of sulfates and
nitrates to total light extinction. To determine the potential impact
from sources of SO<INF>2</INF> and NO<INF>X</INF> emissions (precursors
of SO<INF>4</INF> and NO<INF>3</INF>, respectively), the EWRT values
for SO<INF>4</INF> and NO<INF>3</INF> were combined with emissions (Q)
from sources of SO<INF>2</INF> and NO<INF>X</INF>, respectively.
CenSARA states chose to focus on electric generating units (EGU) and
non-EGU stationary point sources since these sources comprise major
fractions of the NO<INF>X</INF> and SO<INF>2</INF> emissions inventory.
To incorporate the effects of dispersion, deposition and chemical
transformation along the path of the trajectories, emissions were
inversely weighted by the distance (d) between the centers of the grid
cell emitting the emissions and the grid cell containing the IMPROVE
site.
Missouri also included Class I Areas that were identified through
the consultation process as being affected by sources in Missouri, when
the consulting state identified specific Missouri sources that impact
the downwind Class I Area.\40\ Missouri also consulted with MANE-VU on
Class I Areas in Maine, New Jersey, New Hampshire and Vermont. Neither
MANE-VU nor Missouri specifically list which Areas in those states are
affected by Missouri sources. The EPA believes the affected Class I
areas may include:
[[Page 55151]]
Acadia, Moosehorn, and Roosevelt Campobello in Maine; Great Gulf and
Presidential Range-Dry River in New Hampshire; Brigantine Wilderness,
New Jersey; and Lye Brook, Vermont. New Jersey consulted with Missouri.
Neither MANE-VU nor New Jersey specify a source for which Missouri
should conduct a four-factor analysis for its impact on Brigantine
Wilderness. Missouri does not explicitly state why it treats the MANE-
VU Areas different than the other consulted Areas, other than to point
out MANE-VU and New Jersey did not specify a Missouri source to
evaluate. While MANE-VU and New Jersey did not specify a source for
Missouri to analyze, MANE-VU did have six ``Asks'' of other states.
Although Missouri does not include the MANE-VU Class I Areas in the
same way as the other identified Areas, Missouri did consult with MANE-
VU and New Jersey on the ``Asks.'' Despite the apparent inconsistencies
in Missouri's treatment of Class I Areas, we find the resulting
identification of Class I Areas as being impacted by Missouri sources
to be reasonable. However, the EPA finds this requirement is not
separable from the overarching requirement of 40 CFR 51.308(f)(2) to
establish a long-term strategy and as explained in section V.E. of this
preamble, the EPA is proposing to disapprove Missouri's long-term
strategy. Accordingly, the EPA proposes to disapprove this element of
Missouri's second planning period regional haze plan.
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\40\ See Table 37, starting on page 104 of Missouri's submittal.
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D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
Section 51.308(f)(1) requires states to determine the following for
``each mandatory Class I Federal area located within the State'':
baseline visibility conditions for the most impaired and clearest days,
natural visibility conditions for the most impaired and clearest days,
progress to date for the most impaired and clearest days, the
differences between current visibility conditions and natural
visibility conditions, and the URP. This section also provides the
option for states to propose adjustments to the URP line for a Class I
area to account for visibility impacts from anthropogenic sources
outside the United States and/or the impacts from wildland prescribed
fires that were conducted for certain, specified objectives. 40 CFR
51.308(f)(1)(vi)(B).
In Chapter 3 of MoDNR's submittal, Missouri determines and presents
the baseline, natural, and current visibility conditions as well as the
differences between these for both the 20 percent most
anthropogenically impaired days and the 20 percent clearest days for
the state's two Class I Areas consistent with the EPA's RHR and
guidance. Specifically, Missouri presents the latest available
visibility monitoring data as accessed on January 14, 2020, for the
most recent 5-year period (2014-2018) and the baseline period (2000-
2004) as collected at IMPROVE sites and made available on the Federal
Land Manager Environmental Database (FED). Using the EPA's revised
IMPROVE equation (Pitchford et al., 2007), Missouri also calculated the
light extinction contributions from individual particle components. The
state provides the required calculated visibility data as summarized in
Table 1 of this preamble. Missouri also presents the progress made
since the baseline period (2000-2004) as well as the difference between
current (2014-2018) and natural visibility conditions for both the most
impaired and clearest days. Missouri presents the uniform rate of
progress data for each Missouri Class I Area and additional light
extinction information for specific particle components in section
3.3.6 of the state's submittal. Missouri calculated annual URP values
of 0.27 dv/year and 0.29 dv/year needed to reach natural visibility on
the 20% most impaired days at at Hercules-Glades and Mingo,
respectively.\41\ Missouri's URP values for 2028 are shown in Table 1
of this preamble. Missouri did not choose to adjust its URP for
international anthropogenic impacts or to account for the impacts of
wildland prescribed fires as allowed in 40 CFR 51.308(f)(1)(vi)(B).
Missouri additionally compares observed and modeled visibility
conditions and extinction compositions in section 3.3.9 of the
submittal. The EPA further reviews the state's calculations and
visibility data in the technical support document (TSD) as contained in
the docket for this rulemaking. Based on the EPA's review, detailed in
the TSD, the EPA proposes to find that Missouri appropriately
determined the baseline, current and natural visibility conditions as
well as the other required calculations for the two Missouri Class I
Areas and thus meets the requirements of 40 CFR 51.308(f)(1).
Therefore, the EPA proposes to approve this element of Missouri's
submission.
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\41\ See ``Table 9. Uniform Annual Rate of Improvements Needed
to Reach 2016 Natural Visibility for the Most Impaired Days'' in the
MO Regional Haze SIP--Final August 2022.
Table 1--Missouri Class I Areas Visibility Conditions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Baseline 2000-2004 average Natural visibility (dv) Current 2014-2018 average
visibility (dv) -------------------------------- visibility (dv) 2028 Uniform
Missouri Class I area -------------------------------- -------------------------------- rate of
20% Most 20% Clearest 20% Most 20% Clearest 20% Most 20% Clearest progress (dv)
impaired days days impaired days days impaired days days
--------------------------------------------------------------------------------------------------------------------------------------------------------
Hercules Glades......................... 25.17 12.84 9.30 4.69 18.72 9.71 18.82
Mingo................................... 26.31 14.37 9.24 5.3 20.13 11.08 19.48
--------------------------------------------------------------------------------------------------------------------------------------------------------
E. Long-Term Strategy for Regional Haze
1. Source Selection
40 CFR 51.308(f)(2)(i) requires states to ``. . . consider
evaluating major and minor stationary sources or groups of sources,
mobile sources, and area sources. The State must include in its
implementation plan a description of the criteria it used to determine
which sources or groups of sources it evaluated and how the four
factors were taken into consideration in selecting the measures for
inclusion in its long-term strategy.'' As part of its reasonable
progress determinations, the state must describe the criteria used to
determine which sources or group of sources were evaluated (i.e.,
subjected to four-factor analysis) for the second implementation period
and how the Four Factors were
[[Page 55152]]
taken into consideration in selecting the emission reduction measures
for inclusion in the long-term strategy. 40 CFR 51.308(f)(2)(iii).
States may rely on technical information developed by the RPOs of
which they are members to select sources for four-factor analysis and
to conduct that analysis, as well as to satisfy the documentation
requirements under Sec. 51.308(f). Where an RPO has performed source
selection and/or four-factor analyses (or considered the five
additional factors in Sec. 51.308(f)(2)(iv)) for its member states,
those states may rely on the RPO's analyses for the purpose of
satisfying the requirements of Sec. 51.308(f)(2)(i) so long as the
states have a reasonable basis to do so and all state participants in
the RPO process have approved the technical analyses. 40 CFR
51.308(f)(3)(iii). States may also satisfy the requirement of Sec.
51.308(f)(2)(ii) to engage in interstate consultation with other states
that have emissions that are reasonably anticipated to contribute to
visibility impairment in a given Class I area under the auspices of
intra- and inter-RPO engagement.
Missouri explains various methods the state considered when
determining which sources to bring forward for further evaluation.
Ultimately, Missouri primarily relied on the cumulative sulfate and
nitrate extinction weighted residence time (EWRT) multiplied by Q/d
(emissions divided by distance) analysis performed by a CenSARA
contractor to determine the sources with the highest estimated
contributions to Class I Areas. Missouri selected sources contributing
more than 1 percent to any Class I Area for further evaluation.\42\
This resulted in the selection of nine Missouri sources and eighteen
out of state sources. Missouri also considered sources identified by
other states, RPOs or FLMs and explained whether they would be further
evaluated or not and the rationale behind that decision. Missouri
removed two sources initially selected, Buzzi Unicem and Ameren
Meramec, due to decreasing emissions trends. Specifically, Buzzi Unicem
provided the state with updated emissions information and demonstrated
that the reductions were due to an enforceable consent decree entered
in 2017. After the state reevaluated Buzzi Unicem's impacts with the
updated emissions information, the visibility contribution dropped
below the 1 percent threshold used by the state and was therefore
removed from further consideration. Regarding Ameren Meramec, Missouri
points out that the facility voluntarily switched two boilers from
burning coal to natural gas in 2016 and that the facility was expected
to retire by December 2022. Due to the expected shutdown date before
2028, Missouri removed Meramec from consideration of additional control
measures. However, the shutdown date cited by Missouri for Ameren
Meramec is not federally enforceable. The EPA independently confirmed
that emissions from the Meramec facility have indeed decreased
significantly consistent with reduced operations preparing for shutdown
and with no reported emissions or operating hours in 2023. Given these
facts, the EPA finds that removal of these two sources is consistent
with the EPA's 2019 Guidance and 2021 Clarifications Memo. However,
Missouri may also consider in future planning periods whether
evaluation of the removed sources (assuming continued operation of the
sources) would result in a more effective control technology being
found reasonable.
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\42\ See Table 36, starting on page 103 of Missouri's submittal.
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The seven sources Missouri selected for further evaluation are:
John Twitty Energy Center, Associated Electric Cooperative Incorporated
(AECI) New Madrid Power Plant, AECI Thomas Hill Power Plant, Sikeston
Power Station, Ameren Labadie Energy Center, Ameren Rush Island Energy
Center, and Mississippi Lime Company. More information on these sources
is provided here and in the TSD.
John Twitty Energy Center is located in Springfield, Missouri in
Greene County. Units 1 and 2 are dry bottom wall fired boilers. Unit 1
has a capacity of 205 megawatts (MW). Unit 2 has a capacity of 309.6
MW. Both units burn Powder River Basin low sulfur coal. Unit 1 does not
utilize SO<INF>2</INF> controls. Unit 2 has fluidized bed limestone
injection for SO<INF>2</INF> control. Both units have selective
catalytic reduction (SCR) for NO<INF>X</INF> control. Unit 2 also has
overfire air (OFA). Both units have baghouses for particulate control.
AECI New Madrid Power Plant is located near Marston, Missouri in
New Madrid County. Units 1 and 2 are cyclone boilers with capacities of
640 MW each and burn Powder River Basin low sulfur coal. The units do
not utilize SO<INF>2</INF> control. For NO<INF>X</INF> control, both
units have SCR and OFA. For particulate control, both units have
electrostatic precipitators (ESP).
AECI Thomas Hill Power Plant is located in Clifton Hill, Missouri
in Randolph County. Units 1 and 2 are cyclone boilers. Unit 3 is a dry
bottom wall fired boiler. Unit 1 has capacity of 185 MW. Unit 2 has a
capacity of 305 MW. Unit 3 has capacity of 777 MW. All units burn
Powder River Basin low sulfur coal and do not utilize SO<INF>2</INF>
control. Units 1 and 2 have OFA and SCR for NO<INF>X</INF> control.
Unit 3 has OFA, low NO<INF>X</INF> burners, and SCR for NO<INF>X</INF>
control. For particulate control, all 3 units have ESP.
Sikeston Power Station is located near Sikeston, Missouri in Scott
County. Unit 1 is a dry bottom wall fired boiler with capacity of 235
MW and burns Powder River Basin low sulfur coal. Unit 1 has a tray/
Venturi wet scrubber with control device efficiency of 76% (per state's
four factor analysis), but the scrubber is not operating and is not
easily restarted. The facility does not currently utilize any
SO<INF>2</INF> control. For NO<INF>X</INF> control, Unit 1 has low
NO<INF>X</INF> burners with OFA. For particulate control, Unit 1 has an
ESP.
Ameren Labadie Energy Center is located in Labadie, Missouri in
Franklin County. Units 1 and 2 are tangentially fired boilers with
capacities of 675 MW each and burn Powder River Basin low sulfur coal.
Units 3 and 4 are tangentially fired boilers with capacities of 690 MW
each and burn Powder River Basin low sulfur coal. None of the units
utilize control for SO<INF>2</INF>. For NO<INF>X</INF> control, all of
the units have low NO<INF>X</INF> burners, separated overfire air
(SOFA), and neural network optimization. For particulate control, all
of the units have ESP.
Ameren Rush Island Energy Center is located in Festus, Missouri in
Jefferson County. Units 1 and 2 are tangentially fired boilers with
capacities of 621 MW each and burn Powder River Basin low sulfur coal.
The units do not utilize SO<INF>2</INF> control. For NO<INF>X</INF>
control, both units have low NO<INF>X</INF> burners, SOFA, and neural
network optimization. For particulate control, both units have ESP.
Mississippi Lime Company is a lime processing plant located in Ste.
Genevieve, Missouri in Ste. Genevieve County. The following emission
units were determined to be the plant's primary sources of
NO<INF>X</INF> and SO<INF>2</INF> emissions: Peerless Rotary Kilns and
Mississippi Rotary Kilns which fire coal and coke. For SO<INF>2</INF>
control, the Mississippi Rotary Kilns are equipped with wet scrubbers.
Some kilns have lime injection. The remaining Mississippi Rotary Kiln
units do not have lime injection; however, the facility indicates that
the exhaust stream provides inherent process scrubbing of the exhaust
stream due to lime in the process. The facility indicates good
combustion and optimization of processes control of NO<INF>X</INF> on
all the units, and that the Peerless kilns also utilize a preheater.
The units do not have any add-on NO<INF>X</INF> controls.
[[Page 55153]]
Although the EPA finds Missouri's source selection methodology and
the sources selected for further analysis reasonable for the second
planning period, the EPA believes the RHR requirement at 51.308(f)(2),
to consider the four factors in establishing the long-term strategy,
encompasses the selection of sources for further analysis, and
therefore is not separable. For the reasons described in section E.2 of
this preamble, the EPA is proposing to disapprove Missouri's long-term
strategy, which encompasses source selection, in Missouri's second
implementation period regional haze plan as not meeting the
requirements of 40 CFR 51.308(f)(2).
2. Four-Factor Analysis
Each state having a Class I area within its borders or emissions
that may affect visibility in a Class I area must develop a long-term
strategy for making reasonable progress towards the national visibility
goal. CAA section 169A(b)(2)(B). As explained in the Background section
of this document, reasonable progress is achieved when all states
contributing to visibility impairment in a Class I area are
implementing the measures determined--through application of the four
statutory factors to sources of visibility impairing pollutants--to be
necessary to make reasonable progress. 40 CFR 51.308(f)(2)(i). Each
state's long-term strategy must include the enforceable emission
limitations, compliance schedules, and other measures that are
necessary to make reasonable progress. 40 CFR 51.308(f)(2). All new
(i.e., additional) measures that are the outcome of four-factor
analyses are necessary to make reasonable progress and must be in the
long-term strategy. If the outcome of a four-factor analysis and other
measures necessary to make reasonable progress is that no new measures
are reasonable for a source, that source's existing measures are
necessary to make reasonable progress, unless the state can demonstrate
that the source will continue to implement those measures and will not
increase its emission rate. Existing measures that are necessary to
make reasonable progress must also be included as permanent and
federally enforceable \43\ emissions limits in the long-term strategy.
In developing its long-term strategies, a state must also consider the
five additional factors in Sec. 51.308(f)(2)(iv).
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\43\ The EPA also interprets the requirement to be permanent and
federally enforceable as being practically enforceable, i.e., an
operational or emissions limit with the necessary reporting and
recordkeeping requirements such that the source reports compliance
with and that can practically be measured and enforced.
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In Chapter 4 of Missouri's submittal, the state explains the four-
factor analyses performed either by the state or the source for the
seven Missouri sources that were brought forward for further
evaluation. The state describes how each of the four factors is
considered. First, Missouri explains the cost of compliance is
considered by performing a cost analysis for each source and each
technically feasible control measure for both SO<INF>2</INF> and
NO<INF>X</INF>. The state also describes the process used to establish
the cost threshold that the state uses to determine whether the cost
effectiveness of each control measure is reasonable and therefore
should be included in the long-term strategy. Specifically, Missouri
refers to control cost values from the first implementation period,
compiled by the state of Arkansas, to set a cost threshold derived from
those values. Second, Missouri generally describes how the state
assumed the time necessary for compliance for each control type based
on prior EPA studies and literature. Third, Missouri describes how
energy and non-air quality environmental impacts of compliance are
considered. For example, quantifiable energy impacts for a given
control type are included in the cost estimates. Fourth, Missouri
explains the two methods used to estimate the remaining useful life of
the sources evaluated while also considering the remaining useful life
of the control types. In response to comment on this point, Missouri
included cost estimates assuming the default remaining useful life
values that the EPA recommends using for specific control devices.
Ameren Missouri and Mississippi Lime Company provided full four-
factor analyses for their respective facilities. Missouri performed the
four-factor analyses for the remaining sources. The four-factor
analyses presented in Missouri's SIP cover what Missouri determined to
be technically feasible control measures for both SO<INF>2</INF> and
NO<INF>X</INF> for each source. Specifically, the control technologies
evaluated by Missouri are displayed in Table 2 of this preamble.
Table 2--Control Technologies Evaluated by Missouri
------------------------------------------------------------------------
-------------------------------------------------------------------------
SO Control Technologies
------------------------------------------------------------------------
Flue Gas Desulfurization (FGD)--Wet, Spray Dry, Dry Scrubber (50% to 99%
control efficiency):
<bullet> Wet Lime Scrubber, typical control efficiency 90%-99%
<bullet> Wet Limestone Scrubber, typical control efficiency 90%-99%
<bullet> Dual-Alkali Scrubber, typical control efficiency 90%-95%
<bullet> Spray Dry Absorber (SDA), typical control efficiency 90%-
95%
<bullet> Dry Sorbent Injection (DSI), typical control efficiency 50%-
80%
<bullet> Circulating Dry Scrubber
<bullet> Hydrated Ash Reinjection
Limestone Injection.
Low sulfur content coal.
Fuel Switch.
------------------------------------------------------------------------
NO Control Technologies
------------------------------------------------------------------------
Selective Catalytic Reduction (SCR), typical control efficiency 90%.
Low NOX Burners (LNB), typical control efficiency 40%-60%.
Selective Non-Catalytic Reduction (SNCR), typical control efficiency 35%-
50%.
Overfire Air (OFA), typical control efficiency 20%.
Flue Gas Recirculation (FGR).
Low Excess Air (LEA).
------------------------------------------------------------------------
[[Page 55154]]
The full details for the state and source performed four-factor
analyses are included in Appendix C to the state submittal included in
the docket for this action.
Table 3--Summary of Results of Missouri's Four-Factor Analyses
--------------------------------------------------------------------------------------------------------------------------------------------------------
Emission
Annualized reduction Effective cost
Facility Unit Pollutant Control technology cost ($) (tons per ($/ton)
year)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Labadie Energy Center *............ B1.................... SO2................. DSI.................. $27,074,061 7,011 $3,862
NOX................. SNCR................. 3,261,106 450 7,247
B2.................... SO2................. DSI.................. 27,074,061 7,031 3,851
NOX................. SNCR................. 3,261,106 450 7,247
B3.................... SO2................. DSI.................. 25,419,801 6,592 3,856
NOX................. SNCR................. 3,333,575 425 7,844
B4.................... SO2................. DSI.................. 25,419,801 6,854 3,709
NOX................. SNCR................. 3,333,575 425 7,844
Rush Island Energy Center *........ B1.................... SO2................. DSI.................. 28,751,220 6,831 4,209
NOX................. SNCR................. 3,000,218 375 8,001
B2.................... SO2................. DSI.................. 28,822,931 7,337 3,928
NOX................. SNCR................. 3,000,218 375 8,001
Mississippi Lime Company *......... EP-069, EP-070, EP-071 SO2................. DSI.................. 984,041 11.61 84,800
NOX................. SNCR................. 465,644 24 19,100
EP-640, EP-645........ SO2................. DSI.................. 1,344,685 8.62 156,000
NOX................. SNCR................. 809,506 85 9,500
EP-180H, EP-186N, EP- SO2................. Wet Lime Scrubber.... 1,632,862 171.09 9,500
187N.
New Madrid Power Plant *........... B1.................... SO2................. DSI.................. 20,268,773 5,025 4,033
B2.................... SO2................. DSI.................. 22,003,761 5,561 3,957
Thomas Hill Energy Center *........ B1.................... SO2................. DSI.................. 8,255,270 1,837 4,494
B2.................... SO2................. DSI.................. 12,245,800 2,867 4,271
B3.................... SO2................. DSI.................. 29,936,230 7,698 3,889
John Twitty Energy Center *........ B1.................... SO2................. DSI.................. 6,764,511 1,794 3,771
Sikeston Power Station *........... B1.................... SO2................. DSI.................. 13,532,594 3,443 3,930
NOX................. SCR.................. 7,899,846 774 10,209
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Missouri noted these cost estimates were calculated assuming a remaining useful life consistent with the EPA's control cost manual (CCM), however,
some values still do not comport with EPA's control cost manual. Specifically, Missouri assumed a 25-year useful life for Wet FGD, SDA and DSI
controls when the EPA recommends a 30-year useful life. Missouri assumed a 30-year useful life for SCR and a 20-year useful life for SNCR, consistent
with the CCM.
The results of Missouri's four-factor analyses are shown in Table 3
of this preamble. Missouri details the cost effectiveness for each
control type and unit and categorically concludes that each control
measure is not reasonable because the cost effectiveness exceeds the
cost threshold set by Missouri, as discussed later in this section.
Consistent with the finding that new control measures are not
necessary, Missouri finds that current existing operations at each
facility are needed for reasonable progress.
For the reasons described below, the EPA proposes to find that
Missouri has not adequately supported the conclusion that existing
measures satisfy the requirement to make reasonable progress. Missouri
has not definitively shown that further reductions of visibility
impairing pollutants are not reasonable and has not adequately
explained how its approach is consistent with the CAA's requirement to
make reasonable progress. The EPA discusses each of the following lines
of evidence that support this proposed finding. First, the state
rejected otherwise reasonable control measures that would reduce tens
of thousands of tons of visibility impairing pollutants and improve
visibility at Missouri and other states' Class I areas. This decision
was based primarily on the unreasonable justification and use of the
selected cost threshold. Second, the state's cost effectiveness
calculations do not fully align with EPA guidance such as the Control
Cost Manual. When the EPA corrects the deficiencies of Missouri's cost
analysis, we find cost effective controls are available on most if not
all sources evaluated by Missouri. Third, Missouri has not included
practically enforceable emissions limits as part of its long-term
strategy to make reasonable progress. Specifically, the included source
agreements do not contain explicit enforceable emissions limits
associated with existing operations in addition to problematic
provisions included in the source agreements rendering them
unenforceable and not permanent.
Missouri's Justification and Use of the Selected Cost Threshold Is
Unreasonable
Missouri chose to establish a cost threshold based on control cost
values from the first planning period adjusted to 2021 dollars. Using a
database of first planning period control costs,\44\ Missouri selected
a cost threshold of $3,658 per ton specific to SO<INF>2</INF> for EGUs
by calculating the first planning period
[[Page 55155]]
mean cost per ton value plus one standard deviation specifically for
new control technologies (i.e., excluding upgrades to existing controls
or reliance on lower sulfur coal). Application of this threshold means
that Missouri considers all cost effectiveness values greater than
$3,658 per ton to be not cost effective and therefore rejects the
control measure. Using a similar methodology for NO<INF>X</INF>
controls, Missouri selected a cost threshold of $5,370 per ton. The EPA
commented during both the early engagement period and the formal
comment period requesting further documentation and justification for
use of such a cost threshold. In response to comments, Missouri revised
the control cost thresholds to be slightly higher than originally
proposed and provided additional documentation. The EPA also commented
on the fact that multiple sources in the underlying statistical data
(in the Appendix F spreadsheet) installed controls at costs above the
state's threshold including at sources similar to the sources selected
by Missouri. This dataset does not include any Missouri units. By
selecting the mean plus one standard deviation as a cost effectiveness
threshold, Missouri appears to ignore those costs that fall above the
threshold, costs that were found reasonable at nine units (or twenty
percent) of the previously analyzed EGUs, most of similar size to the
Missouri EGUs. EPA guidance states that ``when the cost/ton of a
possible measure is within the range of the cost/ton values that have
been incurred multiple times by sources of similar type to meet
regional haze requirements or any other [Clean Air Act] requirement,
this weighs in favor of concluding that the cost of compliance is not
an obstacle to the measure being considered necessary to make.'' \45\
Missouri states that higher cost/ton values are largely associated with
smaller capacity EGUs and therefore are not directly comparable with
cost values for their larger capacity EGUs. However, in the EPA's
review of the state's cost threshold statistical data, the EPA finds
that values presented for EGUs greater than 500 MW yield maximum costs
in the range of $5,000/ton to $6,000/ton for SO<INF>2</INF> control and
generally exceed the cost effectiveness of SO<INF>2</INF> control at
smaller (less than 500 MW) EGUs.
---------------------------------------------------------------------------
\44\ Missouri relied on a dataset compiled by the State of
Arkansas. Note that the EPA is not proposing an action with respect
to Arkansas's regional haze SIP and we are not commenting on the
approvability of Arkansas's use of the cost methodology, their cost
threshold, or their overall SIP. Missouri's cost threshold dataset
is available in Appendix F to the state submittal, in the docket for
this action.
\45\ EPA's 2019 ``Guidance on Regional Haze State Implementation
Plans for the Second Implementation Period'' <a href="https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period">https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period</a>.
---------------------------------------------------------------------------
Additionally, the EPA notes that CenRAP (predecessor organization
to CenSARA) conducted a sensitivity analysis which evaluated controls
for sources with a Q/d>5 and cost-effectiveness up to $10,000/ton
related to the first regional haze planning period. Based on that
analysis, CenRAP suggested that a range from $4,000 to $5,000/ton (in
2005 dollars) would be a reasonable threshold for controls because of
diminishing emission reductions as costs increase beyond that
range.\46\ In 2021 dollars, the CenRAP range becomes $6,060 to $7,600/
ton.\47\ As described earlier, Missouri relied on other analyses
performed by CenSARA for this planning period, as well as considered
costs from the prior planning period so the EPA finds this analysis
further undermines the reasonableness of Missouri's selected cost
threshold.
---------------------------------------------------------------------------
\46\ See ``Sensitivity Run Specifications for CenRAP
Consultation.pdf,'' available in the docket for this action. See
also ``so2_cost_ton.xls'' and ``nox_cost_ton.xls,'' also available
in the docket for this action.
\47\ Based on the Chemical Engineering Plant Cost Index (CEPCI).
For 2005 the CEPCI value is 468.2. For 2021, the CEPCI value is
708.8.
---------------------------------------------------------------------------
Similarly, the EPA recently proposed a BART FIP for Texas that
references past BART decisions, specifically that several controls were
required by either the EPA or States as BART with average cost-
effectiveness values in the $4,200 to $5,100/ton range (escalated to
2020 dollars).\48\ In 2021 dollars, this range is $5,300/ton to $6,500/
ton.
---------------------------------------------------------------------------
\48\ See 88 FR 28918, 28963. For 2020 the CEPCI value is 596.2.
---------------------------------------------------------------------------
Despite the costs from the first planning period being adjusted to
2021 dollars, the cost thresholds set by Missouri are lower than
historical values found necessary for BART and reasonable progress
determinations as evidenced by the control costs above Missouri's
threshold in the cost effectiveness spreadsheet.\49\ Missouri's cost
thresholds are based on costs found reasonable during the first
planning period and therefore do not account for control costs found
reasonable since that time. For example, other states have since found
higher control costs to be reasonable, such as Oregon \50\ selecting a
$10,000/ton threshold. Additionally, Arkansas's second planning period
regional haze SIP,\51\ which relies on the same underlying statistical
cost data to establish a threshold as used by Missouri, sets a
threshold of $5,086 per ton for EGUs for both SO<INF>2</INF> and
NO<INF>X</INF> control measures.
---------------------------------------------------------------------------
\49\ The sources listed in the cost effectiveness spreadsheet
(Appendix F to the state submittal) are accompanied by a link to the
relevant EPA action.
\50\ The EPA proposed approval of Oregon's second planning
period regional haze SIP on February 23, 2024, 89 FR 13622.
\51\ <a href="https://www.adeq.state.ar.us/air/planning/sip/regional-haze.aspx">https://www.adeq.state.ar.us/air/planning/sip/regional-haze.aspx</a>.
---------------------------------------------------------------------------
One reason for considering higher cost effectiveness thresholds for
the second planning period (compared to the first planning period) is
that most of the cheapest available cost-effective emissions reductions
were required and implemented during the first planning period. These
were typically SO<INF>2</INF> and NO<INF>X</INF> controls at the
largest uncontrolled point sources (mostly electric generating units),
which in many cases had cost-effectiveness values well under $1,000 per
ton. These relatively cheap controls lead to a low bias when using
first planning period cost database numbers to calculate mean costs
(even when adding in one standard deviation). Most remaining point
sources have smaller emissions and do not have cost effective controls
at those previously ``cheap'' levels. However, by itself, that is not a
reasonable justification to reject otherwise potentially cost-effective
controls in the second planning period and beyond. As we move forward
in time to subsequent planning periods, source emissions will get
smaller and potential controls will get more expensive on a cost per
ton basis. However, the statute still requires states to continue to
make reasonable progress towards the national goal.
Missouri's use of the selected cost threshold has the effect of
rejecting control measures that historically have been widely used to
meet the regional haze rule requirements, without requiring additional
emissions reductions or enforceable shutdowns beyond existing
operations. The EPA has not established a bright line or a recommended
cost effectiveness threshold to be used by States. However, the EPA
finds that Missouri's justification and use of the selected cost
threshold to summarily reject control measures, often with cost
effectiveness values just above the selected threshold value, is not
reasonable and does not comport with the stated goals of the CAA and
RHR. This is especially apparent when considering the magnitude of
available emissions reductions at Missouri sources and associated
visibility improvements at Missouri and other states' Class I Areas.
Missouri still has multiple power plants that are uncontrolled for
SO<INF>2</INF>. In fact, Missouri has had the second highest statewide
total SO<INF>2</INF> emissions in the country for each of the last five
years (2018-2022). Further, of the EGUs selected by Missouri, three
were among the top 15 SO<INF>2</INF> emitters in the country in 2023,
with Ameren Labadie being the
[[Page 55156]]
highest SO<INF>2</INF> emitter in 2023.\52\ As described earlier, many
states relied on transport programs to satisfy BART in the first
planning period instead of requiring source specific control
determinations, including Missouri.\53\ While trading programs are
effective at reducing emissions on a regional scale, they do not
require emission reductions or installation of controls on specific
sources. Therefore, individual sources may avoid installing controls or
reducing emissions through the purchase or trading of allowances from
other sources that did opt to install controls or reduce emissions.
Many of the sources selected by Missouri for further evaluation, such
as Ameren Labadie, have not installed post combustion control
equipment. Generally, sources that did not install or consistently
operate post combustion control equipment relied on the purchase of
allowances for trading program compliance. And as discussed further
below, the EPA proposes to find that sources in Missouri have the
potential for cost-effective control options.
---------------------------------------------------------------------------
\52\ According to 2023 reported emissions available at <a href="https://campd.epa.gov/">https://campd.epa.gov/</a>.
\53\ 77 FR 38007, June 26, 2012 and 83 FR 48242, September 24,
2018.
---------------------------------------------------------------------------
As noted previously, the EPA agrees with FLM assertions that there
is the potential for significant visibility improvement associated with
the controls evaluated by Missouri at these sources. However, MoDNR
argues in each four-factor analysis summary that additional controls
are not needed. Among the reasons cited, MoDNR states that ``All Class
I areas impacted by sources in Missouri have made steady and
significant improvement in visibility, and modeling shows they are
projected to be below, or well below, their uniform rate of progress
(URP) glidepaths in 2028.'' \54\ Although the EPA agrees there has been
improvement in the Class I areas impacted by Missouri sources, several
of these Class I areas have the highest remaining anthropogenic
visibility impairment in the country. In particular, based on the
latest available IMPROVE data averaged over the five-year period of
2018-2022, Mammoth Cave, Mingo, and Hercules-Glades are in the top 10
of Class I areas with the greatest anthropogenic visibility
impairment.\55\ Furthermore, the EPA's modeling shows that a
significant amount of visibility impairment is projected to remain in
these Class I areas in 2028.\56\ While not explicitly presented by the
state as a reason for rejecting additional controls, the EPA has
reiterated through regulation and guidance that the URP is not a safe
harbor and an area's position with respect to the URP should not be a
factor in determining whether a control measure is reasonable. See 2019
Guidance at 22, 49, and 50 and 2021 Clarifications Memo at 2, 12, 13
and 15.
---------------------------------------------------------------------------
\54\ See Appendix C-1-7 to the state's submission.
\55\ Based on ``Daily Impairment Values Including Patched
Values'' IMPROVE data spreadsheet,
sia_impairment_daily_budgets_10_23.csv, updated October 2023,
obtained from <a href="https://vista.cira">https://vista.cira</a> .colostate.edu/Improve/rhr-summary-
data/. For the 20% most impaired days from 2018-2022, Mammoth Cave
is the 5th most anthropogenically impaired Class I area with a 5-
year average anthropogenic impairment of 10.4 dv, and Mingo is 6th
on the list at 10.1 dv. Hercules-Glades is 10th on the list with a
5-year average anthropogenic impairment of 8.9 dv.
\56\ Technical Support Document for EPA's Updated 2028 Regional
Haze Modeling, Office of Air Quality Planning and Standards, United
States Environmental Protection Agency (September 2019). See Table
3-2: Base and future year deciview values on the 20% clearest and
20% most impaired days at each Class I area for the base model
period (2014-2017) and future year (2028).
---------------------------------------------------------------------------
The national goal set by Congress outlines both the remedying of
any existing visibility impairment, and also preventing any future
visibility impairment. CAA section 169A(a). Further, the EPA has stated
that in order to accomplish the national goal set by Congress,
cumulative progress must be made including relatively small reductions
and visibility benefits from many sources over a wide area over time.
To that end, visibility should not be used as the sole factor in
rejecting an otherwise reasonable control measure. See 2021
Clarifications Memo at 13.
CAA section 169A(b)(2) requires states to include in their SIPs
``emission limits, schedules of compliance and other measures as may be
necessary to make reasonable progress.'' While these emission limits
must apply to individual sources or units, CAA section 169A(g)(1) does
not explicitly require states to consider the four factors on a source-
specific basis when determining what amount of emission reductions (and
corresponding visibility improvement) constitutes ``reasonable
progress.'' The EPA has consistently interpreted the CAA to provide
states with the flexibility to conduct four-factor analyses for
specific sources, groups of sources, or even entire source categories,
depending on state policy preferences and the specific circumstances of
each state. While the CAA and the RHR provide states with flexibility
in evaluating the four reasonable progress factors, states must
exercise reasoned judgment when choosing which sources, groups of
sources, or source categories to analyze. Consistent with the state's
obligation to exercise reasoned judgment in its analysis, the EPA's
role in reviewing a SIP is not limited to accepting at face value a
state's analysis in its own SIP submission and its determination that
it has fully satisfied the requirements of the CAA. Rather, Congress
tasked the EPA with the responsibility of ensuring that a SIP
submission satisfies the requirements of the CAA. Abundant case law
reflects an understanding that the EPA must evaluate SIP submissions
under CAA section 110(k)(2) and (3).\57\ If a SIP submission is
deficient in whole or in part, the EPA must so find, and if not
corrected, implement the relevant requirements through a FIP under CAA
section 110(c). Courts have held that the EPA's ability to ensure that
a SIP submission satisfies the requirements of the CAA includes the
ability to review a state's analysis to ensure that it is ``reasonably
moored to the Act's provisions and . . . based on reasoned analysis.''
\58\ Thus, EPA's oversight role is ``more than the ministerial task of
routinely approving SIP submissions.'' \59\ If the EPA's role were
otherwise, Congress would not have expressly tasked the agency with
both reviewing SIPs for completeness (CAA section 110(k)(1)(B)) and
reviewing the substance of SIPs (CAA section 110(k)(2)-(4)).
---------------------------------------------------------------------------
\57\ See e.g., Oklahoma v. EPA, 723 F.3d 1201, 1209 (10th Cir.
2013) (upholding EPA's disapproval of ``best available retrofit
technology'' (BART) SIP, noting BART ``does not differ from other
parts of the CAA--states have the ability to create SIPs, but they
are subject to EPA review''); see also Westar Energy v. EPA, 608
Fed. App'x 1, 3 (D.C. Cir. 2015) (``EPA acted well within the bounds
of its delegated authority when it disapproved of Kansas's proposed
[good neighbor] SIP.'').
\58\ North Dakota v. EPA, 730 F.3d 750, 761 (8th Cir. 2013).
\59\ North Dakota v. EPA, 730 F.3d 750, 761 (8th Cir. 2013). See
also Alaska Department of Environmental Conservation v. EPA, 540
U.S. 461, (2004) (concluding that EPA was not limited to verifying
that a BACT determination had been made, but rather EPA could
examine the substance of the BACT determination).
---------------------------------------------------------------------------
For these reasons, the EPA finds that Missouri does not
sufficiently justify the use of the selected cost threshold to
repeatedly reject otherwise reasonable control measures that would
result in potentially meaningful visibility improvements and
significant emissions reductions. And as explained later in this
section, the EPA's revised cost analyses for many of the selected
Missouri sources result in cost effective controls. For these reasons,
the EPA finds that Missouri's rejection of new control measures is
unreasonable and inconsistent with the goals of the RHR.
Deficiencies in Missouri's Cost Analyses
The EPA thoroughly reviewed Missouri's cost analysis for each
[[Page 55157]]
selected source. During both the pre-proposal and formal public comment
period, the EPA commented on the cost analysis presented in the state's
plan. The EPA identified specific errors, over- or underestimations,
inappropriate or unexplained assumptions, and inconsistencies with the
EPA Air Pollution Control Cost Manual.\60\ In response, Missouri
addressed many of the EPA's concerns by correcting certain identified
errors or assumptions. For example, Missouri removed disallowed costs
from the cost assumptions such as owner's costs and updated cost
estimates to also include the default remaining useful life as
recommended by the EPA. However, the EPA believes that Missouri did not
correct all the deficiencies in the cost assumptions and proposes to
find certain aspects of the cost analyses are not well supported. The
EPA further explains these deficiencies in the state's cost analyses in
the technical support document (TSD), contained in the docket for this
action. For example, the EPA commented on Missouri's reliance on
Ameren's four-factor analysis which included a non-default retrofit
factor of 1.5 for wet FGD and SDA and 1.2 for SCR evaluated at the
Ameren facilities (Labadie and Rush Island). Missouri and Ameren did
provide additional documentation in response to the EPA's comment.
However, Missouri's reliance on Ameren's non-default retrofit factors
should include more detailed cost estimates related to the specific
retrofit hardships at each facility. The EPA Air Pollution Control Cost
Manual (CCM) includes a retrofit factor in the control cost
calculations to account for the relative difficulty in installing a
control device. The default value of 1 is associated with average
difficulty in retrofitting an existing unit with a control device. A
value of 0.77 is generally assumed for new units. Therefore, the
default retrofit factor of 1 already includes a 30% increase in costs
compared to new construction. A retrofit factor of 1.5 is the maximum
value allowed in the Control Cost Manual spreadsheets and has the
effect of inflating base cost estimates by 50%. The Control Cost Manual
(CCM) specifically notes that the retrofit factor should be between 0.7
and 1.3 for wet FGD systems and between 0.8 and 1.5 for dry FGD systems
\61\ and documentation of site congestion, site access, complex
ductwork construction and capacity of existing infrastructure is needed
to determine the complexity of the retrofit and associated retrofit
factor. Therefore, to support a retrofit factor above 1 a source should
provide site specific documentation detailing the inflated costs
associated with the CCM criteria (site congestion, site access,
ductwork complexity as well as capacity of existing infrastructure that
would lead to above average retrofit difficulty). The EPA commented on
Missouri's reliance on Ameren's four-factor analysis which included a
non-default retrofit factor of 1.5 for SDA and wet FGD and 1.2 for SCR
evaluated at the two Ameren facilities (Labadie and Rush Island).
Specifically, the EPA commented that the state and source needed to
provide additional documentation to support the use of this non-default
retrofit factor. In response to the EPA's comment, Missouri and Ameren
provided additional documentation in the form of aerial imagery
documenting the site congestion and site access as well as engineering
plans and schematics of potential control device location, rerouted
ductwork, and other construction projected as part of installation of
wet FGD at Labadie. However, these do not appear to be accompanied by
site-specific cost estimates for the various aspects of the retrofit
hardship. Ameren also included cost estimates based on prior source
specific studies for wet FGD and DSI at Labadie and Rush Island (See
Table 3 in Appendices C-6 and C-7 of the state submittal,
respectively). However, no specifics are provided about these prior
studies nor are the underlying cost assumptions provided for comparison
with the new CCM calculations provided. Ameren reasoned that a higher
retrofit factor was needed because the prior source-specific studies
resulted in cost estimates higher than the estimates using the CCM
assumptions. However, this assumption is not well supported. The EPA
does not have access to and therefore cannot review the necessary
underlying cost assumptions from these prior studies to determine the
reasonableness of those estimates. To support the retrofit factor of
1.2 for SCR, the state points to the documentation provided for the wet
FGD as supplied by Ameren but there is no documentation specific to the
retrofit factor for SCR. Additionally, these higher retrofit factors
are utilized in the cost calculations for both Ameren facilities
(Labadie and Rush Island) but the documentation including imagery and
schematics appear specific to Labadie. Therefore, there appears to be
no site-specific documentation provided for the non-default retrofit
factors used for Rush Island.
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\60\ EPA Air Pollution Control Cost Manual, <a href="https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution">https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution</a>.
\61\ Section 5--Chapter 1: Wet and Dry Scrubbers for Acid Gas
Control, Section 1.2.3.5. <a href="https://www.epa.gov/sites/default/files/2021-05/documents/wet_and_dry_scrubbers_section_5_chapter_1_control_cost_manual_7th_edition.pdf">https://www.epa.gov/sites/default/files/2021-05/documents/wet_and_dry_scrubbers_section_5_chapter_1_control_cost_manual_7th_edition.pdf</a>.
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Detailed, technical cost information and robust documentation is
needed to justify the inflated costs resulting from the use of the
maximum retrofit factor value for SO<INF>2</INF> controls at each
Ameren facility. Other electric generating units in the state (and
outside the state) do not rely on such a non-default retrofit factor
despite having similar limitations, such as physical space limitations,
to accommodate control device retrofits.\62\ The EPA invites comment on
the reasonableness of using a non-default retrofit factor and whether
other cases of using such a factor may be instructive to the outcome of
this specific scenario.
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\62\ See the EPA's response to comment including comment on the
range of retrofit factors for wet and dry FGD on EGUs. <a href="https://www.epa.gov/sites/default/files/2021-05/documents/rtcdocument_wet_and_dry_scrubbers_controlcostmanual_7thedition.pdf">https://www.epa.gov/sites/default/files/2021-05/documents/rtcdocument_wet_and_dry_scrubbers_controlcostmanual_7thedition.pdf</a>.
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In addition to reviewing Missouri's cost analyses, the EPA
performed independent cost calculations for certain control measures at
the selected sources to compare with Missouri's cost calculations.
These calculations are summarized below and further detailed in the TSD
included in the docket for this action. The EPA updated certain aspects
of the Missouri cost calculations to follow EPA guidance. For example,
the EPA used the default retrofit factor of 1 in our calculations for
all facilities evaluated. This change, along with the other corrections
made in the EPA's cost analyses, result in cost effectiveness values of
SO<INF>2</INF> controls near or within the cost range established by
Missouri. Further, the EPA calculated cost effectiveness numbers are
similar to maximum control costs implemented in the first planning
period for several states.
The EPA's analysis also changed the emissions baseline used in
determining the emission reduction for a given control to arrive at the
cost effectiveness (or cost per ton) value. While Missouri relied on
the average of reported annual emissions to define the reduction
estimate, the EPA recommends using the maximum annual emissions for the
analyzed time period when setting the baseline emissions to calculate
the cost effectiveness. Similarly, the time period selected for the
baseline emissions also influences the final cost effectiveness value.
For this reason, the EPA performed the cost analyses using both the
same time period used by Missouri
[[Page 55158]]
(2016-2020) for a direct comparison and the most recent time period
(2018-2022) in order to fully evaluate the range of cost effectiveness
values using all currently available data. The baseline emissions
assumption alone makes a significant difference when comparing the
EPA's cost effectiveness values with the state's values, but other
updates to the cost analysis refine and generally reduce the overall
costs. Further, when the calculations are corrected to be consistent
with EPA guidance, there are control costs near and within the cost
range as identified as reasonable by Missouri. For example, the EPA's
calculations result in SO<INF>2</INF> control costs as low as $2,688
per ton. Therefore, we propose to find there are likely cost-effective
control options at most, if not all, sources selected by Missouri. As
noted previously, there are control costs that were previously found
reasonable by states or the EPA, in the dataset used by Missouri to set
a cost threshold, that are similar to the range of costs as calculated
by Missouri and the EPA. States should provide a sufficient
justification in order to reject measures that have been required at
similarly situated facilities in a similar cost range.
The Federal land managers commented on the state's use of an
``unreasonably low threshold'' and the inappropriate assumptions
utilized in the state's cost analyses. On page 54 of Appendix G-2 to
the state's submittal, the National Park Service (NPS) references the
aspects of Missouri's cost analyses that are inconsistent with the EPA
rules or guidance and provides their own estimates of cost
effectiveness for the selected sources, often significantly lower than
the values presented by Missouri. The cost values provided by the NPS
further corroborate the EPA's revised cost analyses, as contained in
the TSD, that result in cost effective controls at most of the state's
selected sources.
In Table 21 of the TSD, the EPA identifies the cost effectiveness
in 2021 dollars for SO<INF>2</INF> control measures such as DSI, SDA
and wet FGD. For NO<INF>X</INF>, the EPA evaluates SCR and SNCR. In
Table 29 of the TSD, the EPA identifies the cost effectiveness in 2021
dollars for SCR and SNCR. The spreadsheets included in the docket
contain all the underlying data for the EPA's cost analyses including
the cost effectiveness values in 2021 dollars using both baseline time
periods as previously mentioned.\63\ For example, the EPA's estimated
cost effectiveness values for DSI range from $2,688 per ton to $4,119
per ton. The EPA's estimated cost effectiveness values for SDA range
from $3,966 per ton to $7,846 per ton. The EPA's estimated cost
effectiveness values for wet FGD range from $4,081 per ton to $9,201
per ton. The EPA's estimated cost effectiveness values for SCR range
from $795 per ton to $27,208 per ton. The lowest costs in this dataset
are associated with the units that already have SCR installed. In this
case, the control cost is entirely associated with operation of the
existing SCR with no additional capital cost of installation since they
are already installed on those units. The EPA's estimated cost
effectiveness values for SNCR range from $7,429 per ton to $16,580 per
ton. Consistent with Missouri's cost analyses, the EPA did not
calculate the cost effectiveness of SNCR on units that already have SCR
installed. Additionally, the EPA did not evaluate SNCR for Sikeston as
a prior technical infeasibility determination was made by the
source.\64\
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\63\ The following values presented as minimum and maximum cost
effectiveness values include the full range of values for both
baseline emission time periods.
\64\ In January 2009, Sikeston submitted an applicability
determination request to install SNCR. However, after initial
testing, Sikeston determined that SNCR was infeasible at the
facility due to stalactite formation, dropping and damaging the
boiler tubes. Based on that information, Missouri removed SNCR from
further consideration in Sikeston's four-factor analysis. Similarly,
the EPA did not evaluate SNCR at Sikeston. See Appendix C-5 to
Missouri's submittal for more information.
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Table 4 of this preamble below includes an abbreviated summary of
the EPA's cost analyses for certain SO<INF>2</INF> control devices. The
EPA's methodology for the cost calculations is included in the TSD
along with the full table of control cost results. In table 4 of this
preamble below, we present only the values associated with wet FGD with
an emissions limit of 0.06 lb/mmBTU. The TSD also presents costs
associated with wet FGD with an emissions limit of 0.04 lb/mmBTU. Cost
effectiveness values associated with the 0.04 lb/mmBTU emissions limit
are lower due to the greater emissions reductions. To be conservative,
this table presents only the highest cost per ton values (i.e., least
cost-effective) from the two time periods evaluated by the EPA for each
control type by unit. Values for both time periods are presented in the
TSD. Generally, the EPA's resulting cost effectiveness values are lower
(more cost effective) than the values presented by Missouri. The cost
effectiveness of wet FGD is higher than SDA. However, wet FGD delivers
significant improvements in cost effectiveness as the tonnage of
SO<INF>2</INF> removal increases due to the greater level of control.
DSI appears the most cost effective given the lower capital cost
compared with SDA and wet FGD, but also comes with lower control
efficiency. For facilities with higher cost effectiveness values for
SDA and wet FGD, DSI may be a reasonable option. The EPA notes that
there are examples nationally of each of these control types being
implemented at large electric generating units such that these types of
controls are technically and economically feasible at such sources.
Specifically, these types of SO<INF>2</INF> controls were implemented
at the sources included in the underlying data for Missouri's cost
threshold, and in some cases, with cost effectiveness values higher
than the threshold set by Missouri. As previously discussed, if
Missouri would have set the cost threshold for this planning period
nearer other states thresholds or near the maximum of costs from the
first planning period (i.e., around $6,000/ton), both the cost
effectiveness values presented by Missouri and the EPA's revised values
would be below that threshold for most SO<INF>2</INF> control types.
Table 4--Summary of the EPA's Cost Effectiveness Values for DSI, SDA and Wet FGD
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2021$ Cost
SO2 reduction (tons effectiveness ($/
Date range per year), based on ton), based on CCM
Facility Unit with highest Control CCM/RCA cost spreadsheet (for SDA/
cost per ton spreadsheet WFGD) and 2023
calculations version of RCA for
DSI
--------------------------------------------------------------------------------------------------------------------------------------------------------
John Twitty........................... 1........................ 2018-2022 DSI...................... 2392 2928
2018-2022 SDA...................... 2520 7011
2018-2022 WFGD..................... 2520 8205
[[Page 55159]]
Labadie............................... 1........................ 2016-2020 DSI...................... 8177 3609
2016-2020 SDA...................... 9008 4780
2016-2020 WFGD..................... 9008 5038
2........................ 2016-2020 DSI...................... 8308 3608
2016-2020 SDA...................... 9023 4774
2016-2020 WFGD..................... 9023 5048
3........................ 2016-2020 DSI...................... 8497 3606
2016-2020 SDA...................... 9100 4825
2016-2020 WFGD..................... 9100 5010
4........................ 2016-2020 DSI...................... 8255 3614
2016-2020 SDA...................... 8692 5019
2016-2020 WFGD..................... 8692 5212
New Madrid............................ 1........................ 2018-2022 DSI...................... 5657 3774
2016-2020 SDA...................... 6104 6444
2016-2020 WFGD..................... 6104 6730
2........................ 2018-2022 DSI...................... 5953 3739
2018-2022 SDA...................... 6518 6057
2018-2022 WFGD..................... 6518 6322
Rush Island........................... 1........................ 2018-2022 DSI...................... 7668 3629
2018-2022 SDA...................... 8264 4732
2018-2022 WFGD..................... 8264 5055
2........................ 2018-2022 DSI...................... 9159 3580
2018-2022 SDA...................... 9689 4111
2018-2022 WFGD..................... 10114 4209
Sikeston.............................. 1........................ 2018-2022 DSI...................... 5661 3711
2018-2022 SDA...................... 4809 4292
2018-2022 WFGD..................... 4809 4901
Thomas Hill........................... 1........................ 2018-2022 DSI...................... 2006 4119
2018-2022 SDA...................... 2248 7846
2018-2022 WFGD..................... 2248 9201
2........................ 2016-2020 DSI...................... 2864 3982
2016-2020 SDA...................... 3210 7559
2016-2020 WFGD..................... 3210 8520
3........................ 2016-2020 DSI...................... 8316 3658
2016-2020 SDA...................... 9371 5300
2016-2020 WFGD..................... 9371 5338
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Table 5 below includes a summary of the EPA's cost effectiveness
values for NO<INF>X</INF> controls.
Table 5--Summary of the EPA's Cost Effectiveness Values for SCR and SNCR
--------------------------------------------------------------------------------------------------------------------------------------------------------
2021$ Cost
NOX reduction (tons effectiveness ($/
Date range per year), based on ton), based on CCM
Facility Unit with highest Control CCM/RCA cost spreadsheet for SCR
cost per ton spreadsheet and 2023 version of
calculations RCA for SNCR
--------------------------------------------------------------------------------------------------------------------------------------------------------
John Twitty........................... 1........................ 2018-2022 SCR...................... 359 3,313
Labadie............................... 1........................ 2018-2022 SCR...................... 948 24,483
2018-2022 SNCR..................... 302 9,064
2........................ 2016-2020 SCR...................... 977 23,960
2018-2022 SNCR..................... 301 9,130
3........................ 2018-2022 SCR...................... 1,106 21,747
2018-2022 SNCR..................... 359 8,245
4........................ 2018-2022 SCR...................... 971 23,878
2018-2022 SNCR..................... 355 8,306
New Madrid............................ 1........................ 2016-2020 SCR...................... 10,691 798
2........................ 2018-2022 SCR...................... 9,617 832
Rush Island........................... 1........................ 2016-2020 SCR...................... 869 23,960
2018-2022 SNCR..................... 208 11,181
2........................ 2018-2022 SCR...................... 763 26,659
[[Page 55160]]
2018-2022 SNCR..................... 130 15,427
Sikeston.............................. 1........................ 2016-2020 SCR...................... 598 15,520
Thomas Hill........................... 1........................ 2016-2020 SCR...................... 3,237 872
2........................ 2016-2020 SCR...................... 4,695 876
3........................ 2016-2020 SCR...................... 4,999 1,349
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The cost effectiveness of SCR is higher than SNCR for units that do
not already have SCR installed. However, SCR delivers significant
improvements in cost effectiveness as the tonnage of NO<INF>X</INF>
removal increases due to the greater level of control of SCR over SNCR.
The cost effectiveness of operating already installed SCR is extremely
cost effective in comparison. As required in the Missouri source
agreements submitted with the SIP, the EPA agrees that existing SCR
should be required to be operated continuously on those units already
equipped with SCR at the John Twitty, Thomas Hill, and New Madrid
plants. Similar to the SO<INF>2</INF> control summary, the EPA's
revised cost effectiveness values for NO<INF>X</INF> controls are
generally lower than the values presented by Missouri. For units that
have relatively low inlet NOx values, post-combustion controls have
lower removal efficiency and accordingly high cost effectiveness
values. Similar to Missouri's assessment, the EPA finds the cost
effectiveness values for installing new post combustion NOx controls
are considerably higher than the highest cost effectiveness values
found to be reasonable in the first planning period (the dataset
underlying Missouri's cost threshold) and therefore may not be
economically feasible for the second planning period.
Importantly as part of this action, the EPA is not proposing that
any given control technology or numeric emissions limit as evaluated in
our TSD is necessary for a given unit. Rather, the EPA provided its own
cost effectiveness calculations as evidence that Missouri's control
decisions, that reject what may be otherwise reasonable control
measures based solely on the state's selected cost threshold, are
unreasonable.
Legal Deficiencies of Missouri's Consent Agreements
To formalize the finding that existing measures are sufficient to
make reasonable progress, Missouri entered into new consent agreements
with each source selected and analyzed, with the exception of
Mississippi Lime Company.\65\ The full source consent agreements are
contained in Appendix E to the state's plan, available in the docket
for this rulemaking.
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\65\ For the Mississippi Lime Company, Missouri's plan appears
to rely on current operational practices consistent with the
parameters and limits in the Mississippi Lime Air Pollution Control
Title V Permit to Operate instead of entering a new consent
agreement. The EPA notes that Title V permit requirements are not
permanent and therefore may not be relied upon for SIP requirements
unless those components of the permit are submitted for inclusion
into the SIP.
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In the new consent agreements, Missouri required that each
facility's future fuel purchase be western sub-bituminous coal derived
from the powder river basin. In addition, each facility agreed to
operate any existing control devices at all times when burning coal in
the boiler(s) except during periods of start-up, shutdown, or
malfunction pursuant to 10 CSR 10-6.050. Through these consent
agreements, the state required two facilities to run their existing
selective catalytic reduction (SCR) technology when burning coal. The
EPA reviewed the consent agreements and provided comment through the
state's public process. The EPA commented on the significant
approvability concerns related to the permanence and enforceability of
the agreements. Specifically, the EPA commented that the agreements do
not contain the necessary numerical emissions limitations associated
with the operational requirements needed to be practically enforceable
and, therefore, are not consistent with the relevant CAA and RHR
requirements. For example, CAA section 110(a)(2)(A) states that each
implementation plan submitted by a state shall ``include enforceable
emission limitations and other control measures, means, or techniques .
. . as well as schedules and timetables for compliance, as may be
necessary or appropriate to meet the applicable requirements of this
chapter.'' \66\ The EPA also commented that the sole requirement to
burn western sub-bituminous coal still allows for a wide variability in
the sulfur content of the coal and, therefore, emissions from the
source. Similarly, the requirement to operate existing SCR technology
without a particular numeric emissions limit or operating parameters
allows for a wide variability in the control efficiency and operations
of the SCR and, therefore, emissions from the source.\67\ Missouri did
not amend the agreements in response to the EPA's formal comments.
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\66\ See CAA Section 110(a)(2) and section 110(a)(2)(A); see
also Committee for a Better Arvin v. U.S. E.P.A., 786 F.3d 1169,
1175 (9th Cir. 2015)
\67\ The EPA provided variability analyses to demonstrate how
these operational requirements without a numerical emissions limit
do not practically limit emissions to an explicit level. See the
EPA's comment letters on both the pre-hearing draft (dated September
28, 2021) and the public notice draft (dated May 5, 2022) of
Missouri's second planning period regional haze SIP.
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The CAA requires that SIPs, including regional haze SIPs, contain
elements sufficient to ensure emission limitations are practically
enforceable. CAA section 110(a)(2) states that the monitoring,
recordkeeping, and reporting provisions of states' SIPs must: ``(A)
include enforceable emissions limitations and other control measures,
means, or techniques (including economic incentives such as fees,
marketable permits, and auctions of emissions rights), as well as
schedules and timetables for compliance, as may be necessary or
appropriate to meet the applicable requirements of this chapter; . . .
(C) include a program to provide for the enforcement of the measures
described in subparagraph (A), and regulation of the modification and
construction of any stationary source within the areas covered by the
plan as necessary to assure that national ambient air quality standards
are achieved, including a permit program as required in parts C and D
of this subchapter;. . . (F) require, as may be
[[Page 55161]]
prescribed by the Administrator--(i) the installation, maintenance, and
replacement of equipment, and the implementation of other necessary
steps, by owners or operators of stationary sources to monitor
emissions from such sources, (ii) periodic reports on the nature and
amounts of emissions and emissions-related data from such sources, and
(iii) correlation of such reports by the State agency with any
emissions limitations or standards established pursuant to this
chapter, which reports shall be available at reasonable times for
public inspection.'' \68\
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\68\ 42 U.S.C. 7410(a)(2)(A), (C), and (F).
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Accordingly, 40 CFR part 51, subpart K, Source Surveillance,
requires the SIP to provide for monitoring the status of compliance
with the regulations in the SIP, including ``[p]eriodic testing and
inspection of stationary sources,'' \69\ and ``legally enforceable
procedures'' for recordkeeping and reporting.\70\ Furthermore, 40 CFR
part 51, appendix V, Criteria for Determining the Completeness of Plan
Submissions, states in section 2.2 that complete SIPs contain: ``(g)
Evidence that the plan contains emission limitations, work practice
standards and recordkeeping/reporting requirements, where necessary, to
ensure emission levels''; and ``(h) Compliance/enforcement strategies,
including how compliance will be determined in practice.'' \71\
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\69\ 40 CFR 51.212.
\70\ Id. Sec. 51.214.
\71\ 40 CFR part 51, appendix V.
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As previously mentioned, emission reduction measures that are
necessary to make reasonable progress may be either new, additional
control measures, or they may be the existing emission reduction
measures that a source is already implementing. See 2019 Guidance at
43; 2021 Clarifications Memo at 8-10. Such measures must be represented
by ``enforceable emissions limitations, compliance schedules, and other
measures'' (i.e., any additional compliance tools) in a state's long-
term strategy in its SIP. 40 CFR 51.308(f)(2). The EPA proposes to find
that the source agreements, submitted by Missouri to serve as the
enforceable mechanism of the long-term strategy, do not meet the
requirements of 40 CFR 51.308(f)(2) to include enforceable emissions
limitations. Specifically, the source agreements do not contain the
necessary numeric emissions limits to constitute a practically
enforceable measure needed for reasonable progress as required by the
RHR.
The EPA also has concerns with the delayed compliance date in the
agreements. Specifically, the consent agreements state that
requirements of the agreements must be complied with ``Starting 180
days after the approval of this agreement by the EPA as an attachment
to Missouri's SIP for the second planning period of the RH program and
consistent with the exemption and termination provisions set forth in
the Consent Agreement.'' The EPA believes the agreements should include
a reasonable compliance date based on the expected time necessary to
implement controls or other operational requirements. The control
requirements under the consent agreements are premised on operating
existing installed emissions controls (for NO<INF>X</INF>) and for
continued purchase and combustion of low sulfur coal (for
SO<INF>2</INF>). The EPA has consistently found that such emissions
control strategies are capable of being implemented in a matter of
weeks, if not immediately given the nature of the requirements. E.g.,
88 FR 36654, 36720-22 (June 5, 2023); 86 FR 23054, 23088-89 (April 30,
2021); and 81 FR 74504, 74561 (October 26, 2016). Instead, the state
tied the effectiveness of these emissions reductions to an event that
is irrelevant to substantive compliance with the regional haze program,
i.e., the effective date of any final action by the EPA to approve the
Consent Agreements into Missouri's SIP. This was improper; as a result
of this provision, even at this point in time, Missouri has not imposed
the requirements of the Consent Agreements on the affected sources and,
under the plain terms of the Consent Agreements, to this day the
covered sources are under no obligation to comply with them.
The EPA further has concerns with certain other provisions
(including but not limited to termination provisions) in the
agreements. For example, the consent agreements contain provisions that
allow for the state and the affected sources to modify them without
following the statutorily-mandated process for SIP revisions and
without requisite analysis by the EPA under CAA section 110(l). See CAA
section 110(i); 110(l). While the EPA will allow for consent agreements
or permitting requirements to be incorporated by reference into a
state's SIP to meet SIP requirements, 50 CFR Pt. 51 App'x V, para.
2.1.(b), it is important that the state provides that to the extent
such provisions are approved and incorporated into the state's SIP,
such provisions, as approved, cannot be modified by later changes made
to the underlying agreements or permits outside of the SIP revision
process. Once approved by the EPA into the SIP as meeting the
applicable SIP requirements, only changes made through the statutory
SIP revision process may modify the approved requirements of the
state's SIP. In this instance, the terms of the Consent Agreements
explicitly authorize the state and the affected sources to cancel the
agreements in toto and without the EPA's approval of such a
modification, which would in effect negate the emissions limitations in
their entirety. This is antithetical to the requirement that SIP
provisions be permanent and enforceable, and not changed except
pursuant to the statutory and regulatory processes for SIP revisions.
The consent agreements should not be unilaterally terminated by
either the source or the state since the state has presented the
consent agreements as necessary to achieve reasonable progress within
the SIP revision submitted to the EPA for approval. Missouri is relying
on Consent Agreements that include termination clauses that render the
agreements and any contained requirements as not permanent and
therefore not consistent with CAA and RHR requirements. Specifically,
paragraph 12 of the consent agreements allows for termination of the
agreement upon ``mutual written agreement of'' the source and the
state. Paragraph 12 remains an unambiguous statement authorizing
termination of the Agreements upon agreement of the parties to
them.\72\ If the source and the MoDNR chose to exercise their rights in
Paragraph 12, the Consent Agreements would be terminated without review
or approval from the EPA and without input from the public, and the
source would be under no obligation to comply. Therefore, the EPA
concludes that paragraph 12 violates the CAA's prohibition on
modification of SIPs outside the authorized SIP revision process
pursuant to sections 110(i) and (l) of the CAA. SIP provisions cannot
authorize a state to make changes in the EPA-approved and federally
enforceable SIP requirements applicable to sources without going
through the statutorily required SIP-revision process. The EPA refers
to SIP provisions that purport to authorize states to make unilateral
changes to existing SIP requirements as impermissible ``director's
discretion'' provisions. See, e.g., 86 FR 15104, 15116 (March 22,
2021). However, the EPA interprets the CAA to allow two
[[Page 55162]]
types of such provisions: (1) where the provision provides director's
discretion for the state to make changes, but specifies that such
changes have no effect for purposes of Federal law or alter SIP
requirements unless and until the EPA approves the changes through a
SIP revision pursuant to CAA requirements; or (2) where the provision
provides director's discretion that is adequately bounded, such that at
the time the EPA approves the SIP provision the Agency can evaluate it
for compliance with applicable CAA requirements and evaluate the
potential impacts of the state's exercise of that discretion. The EPA
interprets CAA section 110(l) to allow SIP provisions with director's
discretion of either type. In the case of an adequately bounded
provision, the EPA considers such provisions consistent with section
110(l) because, at the time of initial approval into the SIP, the
Agency will already have evaluated the provision for compliance with
applicable requirements and evaluated the potential impacts from
exercise of the discretion. E.g., 86 FR 15116, March 22, 2021.
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\72\ The courts would also likely interpret this language
similarly to the EPA. See, e.g., New York v. U.S. EPA, 525 F.Supp.3d
340, 356 (N.D.N.Y. 2021) (```[T]the scope of a consent decree must
be discerned within its four corners . . . .''') (quoting
Firefighters Local Union No. 1784 v. Stotts, 467 U.S. 561, 574
(1984)).
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In Environ. Comm. Fl. Elec. Power v. EPA, 94 F.4th 77 (D.C. Cir.
2024), the D.C. Circuit held that the EPA impermissibly issued a SIP
call, under CAA section 110(k)(5), in its 2015 SSM SIP Action \73\ for
certain SIP provisions applicable to emissions during SSM events,
including certain director's discretion type provisions that the EPA
had previously approved. However, the Court did not foreclose that some
director's discretion provisions may be so unbounded as to interfere
with the Agency's ability to predict the impact on compliance with the
CAA's requirements. Id. At 111. Further, Enviro. Comm. Fl. Elec. Power
concerns the EPA's authority to issue a SIP call for certain provisions
that it previously approved and not the EPA's authority to approve or
disapprove a SIP submission in the first instance. Compare CAA section
110(k)(3) with (k)(5).
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\73\ See 80 FR 33840, June 12, 2015.
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Here, Paragraph 12 of the Consent Agreements in effect provides
unbounded discretion to the state to eliminate the requirements, even
though the MoDNR has submitted these Consent Agreements as necessary to
satisfy Missouri's obligation to achieve reasonable progress in the
regional haze program. Thus, Paragraph 12, which allows Missouri and
its sources to agree between themselves to terminate these emissions
control requirements at any time for any reason, is unacceptably too
unbounded to meet regional haze obligations. Likewise, the EPA finds
Paragraph 12 to be inconsistent with CAA section 110(i) and (l) because
it permits the state not merely discretion to modify some provision
within the overall operation of a broader regulatory scheme, but the
ability to terminate the Agreements completely--i.e., the entirety of
the emissions control program the state has put forward--at will. The
EPA agrees that emissions controls on these sources are necessary
(albeit not sufficient as discussed earlier in this section) for
Missouri to achieve reasonable progress and it would be inappropriate
for the EPA to approve as SIP provisions these Consent Agreements that
the state could eliminate without undertaking the necessary SIP
revision process mandated by the Act.
Here, Paragraph 12 violates the anti-backsliding provisions of
section 110(l) of the CAA, which requires that the EPA shall not
approve any revision of a plan if the revision would interfere with any
applicable requirement concerning attainment and reasonable further
progress. 42 U.S.C. 7410(l). The termination provision would allow a
unilateral amendment to the SIP, potentially removing emissions and
pollution control limits without an evaluation of whether the removal
would interfere with attainment or reasonable further progress or would
interfere with any other applicable requirement of the Act.
As mentioned above, the Consent Agreements include termination
clauses that render them unenforceable depending on the nature of the
action the EPA takes. Even if the EPA could have explored the
possibility of a limited or partial approval of the consent agreements,
it is not able to do this if doing so would render the emissions
control measures established through the consent agreements
unenforceable, by triggering the sources' ability to unilaterally
withdraw from the agreements. Nor does the EPA have discretion to
partially approve the consent agreements by not including within its
approval those provisions of the Consent Agreements such as Paragraph
13 (and others discussed in this section) that are not approvable. To
do so would be to render the SIP revision more stringent than the state
intended, which the EPA is not authorized to do. See Bethlehem Steel
Corp. v. Gorsuch, 742 F.2d 1028 (7th Cir. 1984).
Despite this, there remain multiple problematic provisions of the
Consent Agreements that render them non-permanent and unenforceable. It
is this language in the Agreements themselves, in addition to the
possibility of a future modification to them, that renders them not
approvable as a SIP revision for the purposes of ensuring reasonable
progress under the regional haze program. However, because the consent
agreements are otherwise not approvable, the EPA need not further
evaluate the SSM, force majeure, or other exemption provisions of the
agreements for compliance with the Act. Due to the identified flaws in
the consent agreements as described above, the EPA cannot approve these
consent agreements as a revision to Missouri's SIP nor as enforceable
measures of the long-term strategy under 40 CFR 51.308(f)(2).
For the reasons described in this section and in the TSD, the EPA
proposes to find that Missouri failed to submit an approvable Long-Term
Strategy because it (1) failed to reasonably ``evaluate and determine
the emission reduction measures that are necessary to make reasonable
progress by considering the costs of compliance, the time necessary for
compliance, the energy and non-air quality environmental impacts of
compliance, and the remaining useful life of any potentially affected
anthropogenic source of visibility impairment,'' as required by 40 CFR
51.308(f)(2)(i); CAA section 169A(g)(1); (2) has not adequately
supported its conclusions that existing measures satisfy the
requirement to make reasonable progress; and (3) has not shown that
further reductions of visibility impairing pollutants are not
reasonable and has not adequately explained how its approach is
consistent with the CAA's requirement to make reasonable progress. In
addition, the state rejected otherwise reasonable control measures
based primarily on the unreasonable justification and use of the
selected cost threshold and on cost effectiveness calculations that do
not fully align with EPA guidance. Further, Missouri has not included
practically enforceable emissions limits to ensure that selected
sources comply with the requirements constituting existing measures
Missouri determined as needed to make reasonable progress.
Specifically, the included source agreements do not contain explicit
enforceable emissions limits associated with existing operations and
include problematic termination or other exemption provisions,
rendering them unenforceable and not permanent. Therefore, the EPA is
proposing to disapprove Missouri's Long-Term Strategy as required by 40
CFR 51.308(f)(2).
[[Page 55163]]
3. Additional Long-Term Strategy Requirements
The consultation requirements of Sec. 51.308(f)(2)(ii) provides
that states must consult with other states that are reasonably
anticipated to contribute to visibility impairment in a Class I area to
develop coordinated emission management strategies containing the
emission reductions measures that are necessary to make reasonable
progress. Section 51.308(f)(2)(ii)(A) and (B) require states to
consider the emission reduction measures identified by other states as
necessary for reasonable progress and to include agreed upon measures
in their SIPs, respectively. Section 51.308(f)(2)(ii)(C) speaks to what
happens if states cannot agree on what measures are necessary to make
reasonable progress.
In Appendix G-3, Missouri included documentation of its
consultation with other states and responses to requests from other
states as it relates to the state's development of its long-term
strategy. However, because these elements are not separable from the
overall requirement at 40 CFR 51.308(f)(2) to develop an enforceable
long-term strategy, the EPA accordingly proposes to disapprove all
elements of Missouri's regional haze SIP submission as it relates to
the 40 CFR 51.308(f)(2) rule requirements.
The documentation requirement of Sec. 51.308(f)(2)(iii) provides
that states may meet their obligations to document the technical bases
on which they are relying to determine the emission reductions measures
that are necessary to make reasonable progress through an RPO, as long
as the process has been ``approved by all State participants.''
Section 51.308(f)(2)(iii) also requires that the emissions
information considered to determine the measures that are necessary to
make reasonable progress include information on emissions for the most
recent year for which the state has submitted triennial emissions data
to the EPA (or a more recent year), with a 12-month exemption period
for newly submitted data.
Missouri included emissions information from the most recent
national emissions inventory (NEI) reporting year in its submittal.
Section 4.1.1 of Missouri's submittal details how the state meets the
emissions inventory requirement. Missouri also includes additional
information on the inventory development in Appendix A to the state's
submittal. However, because these elements are not separable from the
overall requirement of 40 CFR 51.308(f)(2) to develop an enforceable
long-term strategy, the EPA accordingly proposes to disapprove all
elements of Missouri's regional haze SIP submission as it relates to
the 40 CFR 51.308(f)(2) rule requirements.
F. Reasonable Progress Goals
Section 51.308(f)(3) contains the requirements pertaining to RPGs
for each Class I area. Section 51.308(f)(3)(i) requires a state in
which a Class I area is located to establish RPGs--one each for the
most impaired and clearest days--reflecting the visibility conditions
that will be achieved at the end of the implementation period as a
result of the emission limitations, compliance schedules and other
measures required under paragraph (f)(2) to be in states' long-term
strategies, as well as implementation of other CAA requirements. The
long-term strategies as reflected by the RPGs must provide for an
improvement in visibility on the most impaired days relative to the
baseline period and ensure no degradation on the clearest days relative
to the baseline period. Section 51.308(f)(3)(ii) applies in
circumstances in which a Class I area's RPG for the most impaired days
represents a slower rate of visibility improvement than the uniform
rate of progress calculated under 40 CFR 51.308(f)(1)(vi). Under Sec.
51.308(f)(3)(ii)(A), if the state in which a mandatory Class I area is
located establishes an RPG for the most impaired days that provides for
a slower rate of visibility improvement than the URP, the state must
demonstrate that there are no additional emission reduction measures
for anthropogenic sources or groups of sources in the state that would
be reasonable to include in its long-term strategy. Section
51.308(f)(3)(ii)(B) requires that if a state contains sources that are
reasonably anticipated to contribute to visibility impairment in a
Class I area in another state, and the RPG for the most impaired days
in that Class I area is above the URP, the upwind state must provide
the same robust demonstration.
In Chapters 5 and 6 of Missouri's SIP submission, the state
describes the process followed to determine the RPGs for each of the
state's Class I areas. Missouri relied on the EPA's modeling of
projected 2028 visibility conditions as the basis for establishing the
RPGs.\74\ Specifically, Missouri established an RPG of 17.44 dv for
Hercules-Glades and 18.88 dv for Mingo. Each of these RPGs is slightly
below the 2028 point on the uniform rate of progress line or glidepath
(18.82 dv for Hercules-Glades and 19.48 dv for Mingo), meaning the
state did not trigger the provision to provide a robust demonstration
as just described.
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\74\ See the EPA's September 2019 memorandum titled,
``Availability of Modeling Data and Associated Technical Support
Document for the EPA's Updated 2028 Visibility Air Quality
Modeling.'' <a href="https://www.epa.gov/sites/default/files/2019-10/documents/updated_2028_regional_haze_modeling-tsd-2019_0.pdf">https://www.epa.gov/sites/default/files/2019-10/documents/updated_2028_regional_haze_modeling-tsd-2019_0.pdf</a>.
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At the time Missouri submitted its SIP, the provision triggering a
robust demonstration did not apply because the states with Class I
areas that are affected by Missouri sources did not submit any RPGs
above the URP. Because we are proposing to disapprove certain elements
of Missouri's SIP, if Missouri chooses to submit a revised SIP to the
EPA, the state should re-evaluate whether the requirement of 40 CFR
51.308(f)(3)(iii) applies to Missouri.
The RPGs should reflect the visibility conditions as a result of
the enforceable emissions limitations and other measures in the state's
long-term strategy as required under 40 CFR 51.308(f)(2). Because the
EPA is proposing to disapprove Missouri's long-term strategy under 40
CFR 51.308(f)(2) through this proposed rulemaking, the EPA is also
proposing to disapprove the RPGs under 40 CFR 51.308(f)(3). If Missouri
elects to submit a new long-term strategy, the state will also need to
provide new RPGs associated with the new long-term strategy.
G. Monitoring Strategy and Other Implementation Plan Requirements
Section 51.308(f)(6) specifies that each comprehensive revision of
a state's Regional Haze SIP must contain or provide for certain
elements, including monitoring strategies, emissions inventories, and
any reporting, recordkeeping and other measures needed to assess and
report on visibility. A main requirement of this subsection is for
states with Class I areas to submit monitoring strategies for
measuring, characterizing, and reporting on visibility impairment.
Compliance with this requirement may be met through participation in
the Interagency Monitoring of Protected Visual Environments (IMPROVE)
network. As noted in Chapter 7 of Missouri's submittal, Missouri
continues to rely on participation in the IMPROVE network for its two
Class I areas monitoring strategies.
Section 51.308(f)(6)(i) requires SIPs to provide for the
establishment of any additional monitoring sites or equipment needed to
assess whether reasonable progress goals to address regional haze for
all mandatory Class I Federal areas within the state are being
achieved. In Chapter 7 of the state plan,
[[Page 55164]]
Missouri describes how the two IMPROVE program monitors in Missouri are
sufficient for determining progress in reducing visibility in the
Missouri Class I areas due to their locations.
Section 51.308(f)(6)(ii) requires SIPs to provide for procedures by
which monitoring data and other information are used in determining the
contribution of emissions from within the state to Regional Haze
visibility impairment at mandatory Class I Federal areas both within
and outside the state. In Chapter 7 of the state plan, Missouri
explains that the assessments of visibility impairment and progress in
reducing visibility impairment at Missouri's two Class I areas, and at
Class I areas in other states that Missouri's emissions may affect, in
the future will use the revised IMPROVE algorithm (Pitchford, 2007) and
will use data as prescribed in the EPA's RHR (40 CFR part 51, subpart
P--Visibility Protection). The assessment will follow, as appropriate,
EPA guidance including Guidance on Regional Haze State Implementation
Plans for the Second Implementation Period (EPA, 2019) and Technical
Guidance on Tracking Visibility Progress for the Second Implementation
Period of the Regional Haze Program (EPA, 20
[…truncated; see source link]Indexed from Federal Register on July 3, 2024.
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