[Federal Register Volume 89, Number 169 (Friday, August 30, 2024)]
[Proposed Rules]
[Pages 71124-71151]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-19189]



[[Page 71123]]

Vol. 89

Friday,

No. 169

August 30, 2024

Part IV





 Environmental Protection Agency





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40 CFR Part 52





Air Plan Approval; Ohio; Regional Haze Plan for the Second 
Implementation Period; Proposed Rule

  Federal Register / Vol. 89 , No. 169 / Friday, August 30, 2024 / 
Proposed Rules  

[[Page 71124]]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R05-OAR-2021-0544; FRL-12175-01-R5]


Air Plan Approval; Ohio; Regional Haze Plan for the Second 
Implementation Period

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve the Ohio regional haze state implementation plan (SIP) revision 
submitted by the Ohio Environmental Protection Agency (Ohio or Ohio 
EPA) on July 30, 2021, which Ohio EPA supplemented on August 6, 2024, 
as satisfying applicable requirements under the Clean Air Act (CAA) and 
EPA's Regional Haze Rule for the program's second implementation 
period. EPA proposes to find that Ohio's SIP submission addresses the 
requirement that States must periodically revise their long-term 
strategies for making reasonable progress towards the national goal of 
preventing any future, and remedying any existing, anthropogenic 
impairment of visibility, including regional haze, in mandatory Class I 
Federal areas, and also addresses other applicable requirements for the 
second implementation period of the regional haze program. EPA is 
taking this action pursuant to sections 110 and 169A of the CAA.

DATES: Written comments must be received on or before September 30, 
2024.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2021-0544 at https://www.regulations.gov or via email to 
[email protected]. For comments submitted at Regulations.gov, 
follow the online instructions for submitting comments. Once submitted, 
comments cannot be edited or removed from the docket. EPA may publish 
any comment received to its public docket. Do not submit to EPA's 
docket at https://www.regulations.gov any information you consider to 
be confidential business information (CBI), Proprietary Business 
Information (PBI), 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. 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, please 
contact the person identified in the FOR FURTHER INFORMATION CONTACT 
section. For the full EPA public comment policy, information about CBI 
or multimedia submissions, and general guidance on making effective 
comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Alisa Liu, Air and Radiation Division 
(AR-18J), Environmental Protection Agency, Region 5, 77 West Jackson 
Boulevard, Chicago, Illinois 60604, (312) 353-3193, [email protected]. 
The EPA Region 5 office is open from 8:30 a.m. to 4:30 p.m., Monday 
through Friday.

SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,'' 
``us,'' or ``our'' is used, we mean EPA.

Table of Contents

I. What action is EPA proposing?
II. Background and Requirements for Regional Haze Plans
    A. Regional Haze Background
    B. Roles of Agencies in Addressing Regional Haze
III. Requirements for Regional Haze Plans for the Second 
Implementation Period
    A. Identification of Class I Areas
    B. Calculations 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
IV. EPA's Evaluation of Ohio's Regional Haze Submission for the 
Second Implementation Period
    A. Background on Ohio's First Implementation Period SIP 
Submission
    B. Ohio's Second Implementation Period SIP Submission and 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. Selection of Sources for Analysis
    2. Emission Measures Necessary To Make Reasonable Progress
    3. Ohio's Long-Term Strategy
    4. EPA's Evaluation of Ohio's Compliance With 40 CFR 
51.308(f)(2)(i)
    5. Consultation With States
    6. Five Additional Factors
    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
V. Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is EPA proposing?

    On July 30, 2021, Ohio EPA submitted a revision to its SIP to 
address regional haze for the second implementation period and 
supplemented it on August 6, 2024. Ohio EPA made this SIP submission to 
satisfy the requirements of the CAA's regional haze program pursuant to 
CAA sections 169A and 169B and 40 CFR 51.308. EPA proposes to find that 
the Ohio regional haze SIP submission for the second implementation 
period meets the applicable statutory and regulatory requirements and 
thus proposes to approve Ohio's submission into its SIP.

II. 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.\1\ CAA 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 169A(a)(1). The CAA further directs EPA to 
promulgate regulations to assure reasonable progress toward meeting 
this national goal. CAA 169A(a)(4). On December 2, 1980, 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 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

[[Page 71125]]

haze. CAA 169B. EPA promulgated the Regional Haze Rule (RHR), codified 
at 40 CFR 51.308,\2\ on July 1, 1999. (64 FR 35714, July 1, 1999). 
These regional haze regulations are a central component of EPA's 
comprehensive visibility protection program for Class I areas.
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    \1\ 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 
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.
    \2\ In addition to the generally applicable regional haze 
provisions at 40 CFR 51.308, 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 
particulate matter (PM) (e.g., sulfates, nitrates, organic carbon, 
elemental carbon, and soil dust) and their precursors (e.g., sulfur 
dioxide (SO2), nitrogen oxides (NOX), and, in 
some cases, volatile organic compounds (VOC) and ammonia 
(NH3)). Fine particle precursors react in the atmosphere to 
form fine particulate matter (PM2.5), which impairs 
visibility by scattering and absorbing light. Visibility impairment 
reduces the perception of clarity and color, as well as visible 
distance.\3\
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    \3\ 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). 
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 deciview, 
since it is not a logarithmic function. See, e.g., 2019 Guidance at 
16, 19, https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period, 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 169A(b)(2); \4\ 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 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 
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 at 35768, July 1, 
1999). 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.\5\ Id. at 
35721.
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    \4\ 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) and (f).
    \5\ In addition to each of the fifty States, 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) and 
(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 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 (dv) 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 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.\6\ 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. See 40 CFR 
51.308(d)(3)(i), (ii). The provisions of 40 CFR 51.308(d) also contain 
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).

[[Page 71126]]

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) \7\ (FLMs) responsible for each Class I area according to 
the requirements in CAA 169A(d) and 40 CFR 51.308(i).
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    \6\ 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, EPA determined 
that natural visibility conditions would be reached in 60 years, or 
2064 (60 years from the baseline starting point of 2004). However, 
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 at 3084, January 10, 2017).
    \7\ 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, 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. 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.
    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, 
EPA issued ``Guidance on Regional Haze State Implementation Plans for 
the Second Implementation Period'' (``2019 Guidance'').\8\ On July 8, 
2021, EPA issued a memorandum containing ``Clarifications Regarding 
Regional Haze State Implementation Plans for the Second Implementation 
Period'' (``2021 Clarifications Memo'').\9\ Additionally, 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''),\10\ 
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'').\11\
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    \8\ Guidance on Regional Haze State Implementation Plans for the 
Second Implementation Period. https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period EPA Office of Air Quality Planning and 
Standards, Research Triangle Park (August 20, 2019).
    \9\ Clarifications Regarding Regional Haze State Implementation 
Plans for the Second Implementation Period. https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf. EPA Office of Air Quality Planning and Standards, 
Research Triangle Park (July 8, 2021).
    \10\ Technical Guidance on Tracking Visibility Progress for the 
Second Implementation Period of the Regional Haze Program. https://www.epa.gov/sites/default/files/2021-03/documents/tracking.pdf EPA 
Office of Air Quality Planning and Standards, Research Triangle 
Park. (December 20, 2018).
    \11\ 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. https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program EPA Office 
of Air Quality Planning and Standards, Research Triangle Park (June 
3, 2020).
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    As explained in the 2021 Clarifications Memo, 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.\12\
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    \12\ 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. 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),\13\ which include 
representation from State and Tribal governments, 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 particulate matter and other pollutants leading to 
regional haze, and help States meet the consultation requirements of 
the RHR.
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    \13\ RPOs are sometimes also referred to as ``multi-
jurisdictional organizations,'' or MJOs. For the purposes of this 
notice, the terms RPO and MJO are synonymous.
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    The Lake Michigan Air Directors Consortium (LADCO) is an RPO that 
includes the States of Illinois, Indiana, Michigan, Minnesota, Ohio, 
and Wisconsin. LADCO's work is a

[[Page 71127]]

collaborative effort of State governments, Tribal governments, and 
various Federal agencies established to initiate and coordinate 
activities associated with the management of regional haze, visibility, 
and other air quality issues in the Midwest. Along with the six LADCO 
States, participants in LADCO's Regional Haze Technical Workgroup 
include EPA, U.S. National Parks Service (NPS), U.S. Fish and Wildlife 
Service (FWS), and U.S. Forest Service (USFS).

III. Requirements for Regional Haze Plans for the Second Implementation 
Period

    Under the CAA and EPA's regulations, all 50 States, the District of 
Columbia, and the U.S. Virgin Islands were 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 169A(b)(2)(B). To this end, 40 CFR 51.308(f) lays 
out the process by which States determine what constitutes their long-
term strategies, with the order of the requirements in 40 CFR 
51.308(f)(1) through (3) generally mirroring the order of the steps in 
the reasonable progress analysis \14\ and (f)(4) through (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), 
(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 51.308(f)(2)(iv) separately provides five ``additional 
factors'' \15\ 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. 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 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)and(3).
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    \14\ 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 51.308(d), ``tracked the actual planning 
sequence.'' (82 FR 3091, January 10, 2017).
    \15\ 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 40 CFR 
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 EPA according to the requirements applicable to all SIP 
revisions under the CAA and EPA's regulations. See CAA 169A(b)(2); CAA 
110(a). Upon EPA approval, a SIP is enforceable by the Agency and the 
public under the CAA. If EPA finds that a State fails to make a 
required SIP revision, or if EPA finds that a State's SIP is incomplete 
or disapproves the SIP, the Agency must promulgate a Federal 
implementation plan (FIP) that satisfies the applicable requirements. 
See CAA 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, EPA determined that all States contribute to visibility impairment 
in at least one Class I area 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.'' 64 FR 35714 
at 35720-22, July 1, 1999.
    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, 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. See 
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 40 CFR 
51.308(f)(1) related to tracking visibility improvement over time. The 
requirements of this section apply only to States having Class I areas 
within their borders; the required calculations must be made for each 
such Class I area. EPA's 2018 Visibility Tracking Guidance \16\ 
provides recommendations

[[Page 71128]]

to assist States in satisfying their obligations under 40 CFR 
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-
05, January 10, 2017.
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    \16\ The 2018 Visibility Tracking Guidance references and relies 
on parts of the 2003 Tracking Guidance: ``Guidance for Tracking 
Progress Under the Regional Haze Rule,'' which can be found at 
https://www.epa.gov/sites/default/files/2021-03/documents/tracking.pdf.
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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 percent clearest 
(the 20 percent of monitored days in a calendar year with the lowest 
values of the deciview index) and 20 percent most impaired days (the 20 
percent of monitored days in a calendar year with the highest amounts 
of anthropogenic visibility impairment).\17\ 40 CFR 51.301. A State 
must calculate visibility conditions for both the 20 percent clearest 
and 20 percent 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,\18\ 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 to reach natural visibility 
conditions.
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    \17\ This action also refers to the 20 percent clearest and 20 
percent most anthropogenically impaired days as the ``clearest'' and 
``most impaired'' or ``most anthropogenically impaired'' days, 
respectively.
    \18\ 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 3098: 
``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 dv, that would 
need to be achieved during each implementation period 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.\19\ 
Additionally, in the 2017 RHR Revisions, 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 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 not necessary for reasonable 
progress. See 82 FR 3078 at 3107, January 10, 2017, footnote 116.
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    \19\ 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.
---------------------------------------------------------------------------

    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 40 CFR 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 
(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 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).
    The construct of 40 CFR 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 EPA 
previously explained, consistent with the first implementation period, 
EPA generally expects that each State will analyze at least 
SO2 and NOX 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 Regional Haze Rule, 
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

[[Page 71129]]

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.
    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.\20\
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    \20\ Similarly, in responding to comments on the 2017 RHR 
Revisions, 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 (81 FR 26942 at 26987-88, May 4, 2016).
---------------------------------------------------------------------------

    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.\21\ This is accomplished by considering the four factors--``the 
costs of compliance, the time necessary for compliance, and the energy 
and non-air quality environmental impacts of compliance, and the 
remaining useful life of any existing source subject to such 
requirements.'' CAA 169A(g)(1). 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 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,\22\ a State 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.
---------------------------------------------------------------------------

    \21\ The CAA provides that, ``[i]n determining reasonable 
progress there shall be taken into consideration'' the four 
statutory factors. CAA 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.
    \22\ ``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.
---------------------------------------------------------------------------

    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 emissions reduction measures for sources), 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 emissions rate than a source has achieved or 
could potentially achieve using its existing measures should also 
consider lower emissions 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. 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. 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.\23\ 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, 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, 40 CFR 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

[[Page 71130]]

measure for inclusion in its long-term strategy.''
---------------------------------------------------------------------------

    \23\ 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.
---------------------------------------------------------------------------

    As explained above, 40 CFR 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 40 CFR 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.\24\ 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 
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 emissions rate, it may not be 
necessary to have those measures in the long-term strategy to prevent 
future emissions increases and future visibility impairment. 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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    \24\ 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 EPA for inclusion in their SIPs but are not required to do 
so. See, e.g., 82 FR 3078 at 3108-09, 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 
40 CFR 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, 40 CFR 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 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, 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.\25\ 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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    \25\ 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).
---------------------------------------------------------------------------

    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 51.308(f)(2)(iv) separately 
provides five ``additional factors'' \26\ 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. 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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    \26\ 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.
---------------------------------------------------------------------------

    Because the air pollution that causes regional haze crosses State 
boundaries, 40 CFR 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

[[Page 71131]]

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). 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 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 
dv--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.\27\ 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.
---------------------------------------------------------------------------

    \27\ 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, control 
determinations by other States, and 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.
---------------------------------------------------------------------------

    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. While States are not 
legally obligated to achieve the visibility conditions described in 
their RPGs, 40 CFR 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-
2004. See 40 CFR 51.308(f)(1)(i), 82 FR 3078 at 3097-98, 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 at 3093, 
3099-3100; 2019 Guidance at 22; 2021 Clarifications Memo at 15-16.

E. Monitoring Strategy and Other State Implementation Plan Requirements

    The provisions of 40 CFR 51.308(f)(6) require States to have 
certain strategies and elements in place for assessing and reporting on 
visibility. Individual requirements under this section 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

[[Page 71132]]

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 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), 
(f)(6)(iv). The IMPROVE monitoring data is used to determine the 20 
percent most anthropogenically impaired and 20 percent 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), (iii). The 
provisions of 40 CFR 51.308(f)(6)(v) further require 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.\28\ 
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.\29\
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    \28\ See ``Step 8: Additional requirements for regional haze 
SIPs'' in 2019 Guidance at 55.
    \29\ 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 40 CFR 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.'' \30\ Under this 
provision, if 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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    \30\ 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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F. Requirements for Periodic Reports Describing Progress Towards the 
Reasonable Progress Goals

    The provisions of 40 CFR 51.308(f)(5) require a State's regional 
haze SIP revision to address the requirements of paragraphs 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 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, 40 
CFR 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), and 
then to calculate the difference between those current conditions and 
baseline (2000-2004) visibility conditions to assess progress made to 
date. See 40 CFR 51.308(g)(3)(ii). 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(g)(3)(iii), (f)(5). 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(g)(4), (f)(5). Changes in emissions should be identified by 
the type of source or activity. The provisions of 40 CFR 51.308(g)(5) 
also address 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 explain 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

[[Page 71133]]

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). For 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 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).

IV. EPA's Evaluation of Ohio's Regional Haze Submission for the Second 
Implementation Period

A. Background on Ohio's First Implementation Period SIP Submission

    Ohio submitted its regional haze SIP for the first implementation 
period for 2007-2018 to EPA on December 31, 2008. Based on the failure 
to submit a complete SIP addressing all elements of 40 CFR 51.308, EPA 
issued a finding of failure to submit on January 9, 2009. 74 FR 2392, 
January 15, 2009.
    On March 11, 2011, Ohio submitted an updated first implementation 
period regional haze SIP, and EPA finalized a limited approval on May 
29, 2012. 77 FR 39177, July 2, 2012.
    In a separate action, EPA finalized a limited disapproval of Ohio's 
March 11, 2011, regional haze SIP because of deficiencies arising from 
the remand of the Clean Air Interstate Rule (CAIR). EPA promulgated a 
Federal Implementation Plan (FIP) to replace Ohio's reliance on CAIR 
with the Cross-State Air Pollution Rule (CSAPR). 77 FR 33642, June 7, 
2012.
    On April 14, 2014, Ohio submitted a revision to its March 11, 2011, 
regional haze SIP and supplemented it on July 27, 2015, to extend the 
compliance date for the non-EGU BART emission limits for 
SO2, which EPA approved on February 22, 2016. 81 FR 11445, 
March 4, 2016.
    On November 30, 2016, Ohio EPA submitted a second revision to 
change reliance on CAIR to reliance on the CSAPR, which EPA approved on 
April 30, 2018, converting EPA's limited approval/limited disapproval 
of Ohio's March 11, 2011, regional haze SIP to a full approval, and 
withdrawing the FIP provisions that addressed the limited disapproval. 
See 83 FR 21719, May 10, 2018. 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).
    Pursuant to 40 CFR 51.308(g), Ohio was also responsible for 
submitting a five-year progress report as a SIP revision for the first 
implementation period, which it did on March 11, 2016. EPA approved 
this five-year progress report as a revision to the Ohio SIP at 40 CFR 
52.1870(e) on December 8, 2017 (82 FR 60543, December 21, 2017).

B. Ohio's Second Implementation Period SIP Submission and EPA's 
Evaluation

    In accordance with CAA sections 169A and the RHR at 40 CFR 
51.308(f), Ohio EPA submitted a revision to the Ohio SIP on July 30, 
2021, to address its regional haze obligations for the second 
implementation period, which runs through 2028. Ohio EPA supplemented 
its SIP submittal on August 6, 2024. Ohio initiated an FLM consultation 
process and provided three public comment periods on the regional haze 
SIP for the second implementation period. The first public comment 
period on the initial SIP revision ran from May 10, 2021 through June 
28, 2021, and a public hearing was held on June 14, 2021. The second 
public comment period, limited to proposed emission limitations for 
three sources, ran from January 16, 2024 through March 18, 2024, and a 
public hearing was held on March 18, 2024. The third public comment 
period, regarding draft administrative orders effectuating the proposed 
emission limitations for the three sources, ran from June 6, 2024 
through July 8, 2024, and a public hearing was held on July 9, 2024. 
Ohio received and responded to comments from FLMs and the public. Ohio 
included the comments and responses in Appendices K1-K4, L1-L4, M1-M3, 
N1-N2, O, and P9-P12 of its July 30, 2021, submission and in Appendices 
C3, C4, C7, C8, E2, E3, F2, F3, F4, F5, and G of its August 6, 2024, 
supplement.
    The following sections describe Ohio's SIP submission, including 
Ohio's assessment of progress made since the first implementation 
period in reducing emissions of visibility impairing pollutants, and 
the visibility improvement progress at nearby Class I areas. Also 
described is Ohio's August 6, 2024 supplement, which provides 
administrative orders effectuating emission limitations for three 
sources to be incorporated into the regulatory portion of Ohio's SIP at 
40 CFR 52.1870(d). This action also contains EPA's evaluation of Ohio's 
submission against the requirements of the CAA and the RHR for the 
second implementation period of the regional haze program.

C. Identification of Class I Areas

    The provisions of section 169A(b)(2) of the CAA require 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 (f)(2), which requires each 
State's plan to include a long-term strategy that addresses regional 
haze in such Class I areas.
    Ohio has no Class I areas within its borders that are among the 156 
mandatory Class I Federal areas where EPA deemed visibility to be an 
important value. See 40 CFR part 81, subpart D. Thus, Ohio EPA only 
considered out-of-state mandatory Class I Federal areas covered under 
the RHR.
    Ohio is a member of LADCO and participated in its regional approach 
for developing a strategy for making reasonable progress towards the 
national visibility in the northern Midwest Class I areas. Ohio EPA 
reviewed technical analyses conducted by LADCO to determine what Class 
I areas outside the State are affected by Ohio emission sources. For 
the second regional haze implementation period, LADCO used the 
Comprehensive Air Quality Model with extensions Particulate Matter 
Source Apportionment Tool (PSAT). LADCO tagged States and regions as 
well as individual point sources and inventory source groups to 
apportion emissions to States and regions. LADCO assessed relative 
visibility impacts in 2028 by projecting representative emissions 
inventories and known emission controls from 2016.\31\ A group of RPOs,

[[Page 71134]]

States, and EPA established 2016 as the base year for a national air 
quality modeling platform for future ozone, PM2.5, and 
regional haze SIP development because of fairly typical ozone 
conditions and wildfire conditions.\32\ LADCO relied upon EPA's 
inventory estimates for 2016 and 2028 for most emission sectors as 
described in EPA's September 19, 2019, ``Availability of Modeling Data 
and Associated Technical Support Document for the EPA's Updated 2028 
Visibility Air Quality Modeling,'' (EPA's Updated 2028 Visibility Air 
Quality Modeling).\33\ For Electric Generating Units (EGUs), LADCO used 
forecasts from the Eastern Regional Technical Advisory Committee 
(ERTAC) based on continuous emissions monitoring data from 2016 instead 
of the Integrated Planning Model used in EPA's 2016 modeling platform. 
LADCO also incorporated State-reported changes to EGUs received through 
September 2020 to estimate 2028 EGU emissions.
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    \31\ See appendix A of Ohio EPA's SIP submittal. Details of the 
analysis and source-apportioned visibility contributions at Class I 
areas within the LADCO region for regional haze second planning 
period are documented in LADCO's modeling technical support document 
(TSD), dated June 17, 2021.
    \32\ See ``Base Year Selection Workgroup Final Report,'' 
produced by the Inventory Collaborative Base Year Selection 
Workgroup, April 5, 2017. https://www.wrapair2.org/pdf/2017-12-12_Base_Year_Selection_Report_V1.1.pdf.
    \33\ EPA, Office of Air Quality Planning and Standards, 
``Availability of Modeling Data and Associate Technical Support 
Document for EPA's Updated 2028 Visibility Air Quality Modeling,'' 
September 19, 2019. https://www.epa.gov/sites/default/files/2019-10/documents/updated_2028_regional_haze_modeling-tsd-2019_0.pdf
---------------------------------------------------------------------------

    Ohio identified affected Class I areas where progress toward 
natural visibility conditions may be impacted by emissions from sources 
in Ohio. Ohio reviewed technical analyses conducted by LADCO and other 
RPOs to determine which Class I areas outside the State are affected by 
Ohio emission sources.
    For the second implementation period, Ohio used LADCO's modeled 
emissions projections for 2028 as a framework to assess the potential 
for changes in visibility-impairing emissions. Like the metrics used in 
the first implementation period,\34\ Ohio EPA retained the 2 percent 
light extinction threshold for determining Ohio's contribution to 
visibility at Class I areas. LADCO's modeling results showed that a 2 
percent light extinction threshold, when applied to all six LADCO 
States and seven other States, would account for 92 percent or more of 
the total light extinction at the Class I areas located in the LADCO 
States on the most impaired days. When applying the 2 percent total 
light extinction threshold, Ohio identified 17 Class I areas affected 
by Ohio emission sources for the second implementation period. These 
Class I areas, along with Ohio's 2028 projected contributions to 
visibility impairment, are: Sipsey Wilderness Area in Alabama (2.3 
percent); Cohutta Wilderness Area in Georgia (2.1 percent); Mammoth 
Cave National Park in Kentucky (5.9 percent); Seney Wilderness Area in 
Michigan (2.0 percent); Great Gulf Wilderness Area (2.5 percent) and 
Presidential Range--Dry River Wilderness in New Hampshire (2.5 
percent); Brigantine Wilderness Area in New Jersey (4.3 percent); 
Linville Gorge (3.8 percent) and Shining Rock Wilderness Areas (2.8 
percent) and Swanquarter National Wildlife Refuge in North Carolina 
(3.6 percent); Great Smoky Mountains National Park (2.3 percent) and 
Joyce-Kilmer-Slickrock Wilderness Area in Tennessee (2.3 percent); Lye 
Brook Wilderness Area in Vermont (3.3 percent); James River Face 
Wilderness Area (6.5 percent) and Shenandoah National Park in Virginia 
(10.5 percent); and Dolly Sods (13.1 percent) and Otter Creek 
Wilderness Areas (13.1 percent) in West Virginia.\35\ Based on the 
adjusted URP glidepaths for each of these Class I areas provided in 
EPA's Updated 2028 Visibility Air Quality Modeling, visibility 
conditions, as depicted in Table 1 of Ohio's SIP submission, are 
projected to be below their respective glidepaths in 2028. Visibility 
conditions at Dolly Sods and Otter Creek Wilderness Areas, the Class I 
areas impacted most significantly by Ohio, are projected to be 
approximately 5 dv below their respective glidepaths in 2028.
---------------------------------------------------------------------------

    \34\ See Section III.2. and Appendix A of Ohio's SIP submission 
for LADCO's technical support document and supporting materials.
    \35\ The list of Class I areas impacted by Ohio, including the 
2028 projections for visibility on the 20 percent most impaired days 
and Ohio's contribution, is found in Table 1 of Ohio's SIP 
submission.
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D. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress

    The provisions of 40 CFR 51.308(f)(1) require 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).
    Ohio has no mandatory Class I areas within its borders to which the 
requirements of the visibility protection program apply in 40 CFR part 
81, subpart D, and therefore, 40 CFR 51.308(f)(1) and its requirements 
do not apply.

E. Long-Term Strategy for Regional Haze

    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 169A(b)(2)(B). As explained in the Background section of this 
notice, 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 in the 
long-term strategy. In developing its long-term strategies, a State 
must also consider the five additional factors in 40 CFR 
51.308(f)(2)(iv). 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 taken into consideration in selecting the emission reduction 
measures for inclusion in the long-term strategy. 40 CFR 
51.308(f)(2)(iii).

[[Page 71135]]

1. Selection of Sources for Analysis
    This section summarizes how Ohio EPA's SIP submission addressed the 
requirements of 40 CFR 51.308(f)(2)(i) of the Regional Haze Rule. 
Specifically, it describes the criteria Ohio EPA used to determine the 
selection of sources or groups of sources it evaluated for an analysis 
of potential emission control measures. 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 40 CFR 51.308(f).
    In selecting sources to determine possible additional control 
measures during the second planning period, Ohio EPA considered 
NOX, SO2, PM2.5, and NH3, 
which are direct or precursor pollutants than can impair visibility. 
Based on EPA's Updated 2028 Visibility Air Quality Modeling showing 
that the EGU and non-EGU point source sectors contribute 37 to 76 
percent of the visibility impact at Class I areas impacted by Ohio 
sources, Ohio found it reasonable to focus on point sources for the 
second implementation period.
    To assist States with their source selection, LADCO generated 
source lists based on total process-level emissions (Q) divided by 
distance (d) to the nearest Class I area, where Q/d was used as a 
surrogate quantitative metric of visibility impact. Total emissions of 
Q refer to the sum of NOX, SO2, PM2.5, 
and NH3. The National Emissions Inventory Collaborative 2016 
alpha inventory was selected by participants in the LADCO Regional Haze 
Technical Workgroup for the Q/d analysis in 2018 as the best available 
inventory at that time. LADCO identified unit level sources above Q/d 
thresholds of 1, 4, and 10, providing key information the States could 
use to select potential sources to be subject to the four-factor 
analysis. For details on the data and methods used in the Q/d analysis, 
see LADCO's October 14, 2020, technical memorandum ``Description of the 
Sources and Methods Used to Support Q/d Analysis for the 2nd Regional 
Haze Planning Period'' and section 5 of LADCO's June 17, 2021, 
Technical Support Document ``Modeling and Analysis for Demonstrating 
Reasonable Progress for the Regional Haze Rule 2018-2028 Planning 
Period,'' (LADCO's 2021 TSD) contained in appendix A and B of Ohio's 
SIP submission.
    In addition to LADCO's Q/d analysis, Ohio EPA compared point source 
inventories from the 2017 National Emissions Inventory (NEI) and the 
2018 Ohio Emissions Inventory System (EIS) \36\ with the emissions used 
in LADCO's analysis. For sources where Q was greater than 500 tons per 
year for the sum of NOX, SO2, PM2.5, 
and NH3 in either the emissions data from the 2016 alpha 
inventory, 2017 NEI, or 2018 Ohio EIS, Ohio calculated updated Q/d 
values to determine if any additional sources would be identified 
beyond those in LADCO's list. However, the process did not result in 
the identification of any additional sources. As such, Ohio EPA relied 
upon the Q/d information developed by LADCO to select emission units 
for further analysis.
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    \36\ Ohio EPA's Emission Inventory System (EIS) is a compilation 
of data describing emissions from different sources of air 
pollution. Ohio EPA's EIS data and reports are available at https://epa.ohio.gov/divisions-and-offices/air-pollution-control/reports-and-data/emision-inventory-system.
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    Ohio EPA began by using a unit Q/d greater than 5 as a threshold 
for selecting sources for further evaluation. Then on May 12, 2020, and 
October 2, 2020, Ohio received lists of sources recommended for four-
factor analyses that were prepared by NPS and USFS, respectively, and 
are included in Appendices K2, K3, and K4 in Ohio's SIP submission. The 
list from NPS identified facilities with emissions comprising 80 
percent of Ohio's total Q based on only SO2 and 
NOX that covered a mix of years from 2014 to 2017, whereas 
the list from USFS identified facilities with a Q/d greater than 8 as 
calculated by LADCO with the addition of VOC to represent 80 percent of 
Ohio's total Q at the closest Class I area to Ohio managed by USFS, the 
Dolly Sods Wilderness Area. While Ohio EPA's primary approach was to 
consider Q/d on an individual unit basis, the FLM's consideration of Q/
d on a facility-wide basis prompted Ohio to include facility-wide 
contribution as an additional consideration. As such, Ohio EPA added a 
secondary selection criterion for facility-wide Q/d and developed a 
two-tiered approach to capture significant point source emissions in 
Ohio for further analysis. Ohio EPA's first tier identified individual 
units with a Q/d greater than 5 for a potential four-factor analysis. 
For facilities with Q/d greater than 10, Ohio EPA's second tier 
selected individual units with Q/d greater than 4 for a potential four-
factor analysis. This secondary selection criteria resulted in the 
addition of two units to Ohio EPA's initial list for a total of 38 
units at 16 facilities, accounting for 73 percent of the total Q for 
all sources in Ohio with Q greater than 0.1 tons per year, including 80 
percent of SO2, 57 percent of NOX, 47 percent of 
PM2.5, and 23 percent of NH3.
    Using this two-tiered approach, Ohio EPA identified the following 
facilities and units: Avon Lake Power Plant Unit B012; Cardinal Power 
Plant Units B001, B002, B009; Carmeuse Lime, Inc.--Maple Grove 
Operations Units P003, P004; Conesville Power Plant Units B004, B007, 
B008; City of Orrville Department of Public Utilities Units B001, B004; 
Dover Municipal Light & Power Plant Unit B004; DP&L, J.M. Stuart 
Generating Station Units B001, B002, B003, B004; DP&L, Killen 
Generating Station Unit B001; FirstEnergy Generation LLC--Bay Shore 
Plant Unit B006; General James M. Gavin Power Plant Units B003, B004; 
Haverhill Coke Company LLC Unit P902; Miami Fort Power Station Units 
B015, B016; Ohio Valley Electric Corp.--Kyger Creek Station Units B001, 
B002, B003, B004, B005; P.H. Glatfelter Company--Chillicothe Facility 
Units B002, B003; W.H. Sammis Plant Units B007, B008, B009, B010, B011, 
B012, B013; and Zimmer Power Station Unit B006.
    Ohio then refined the list above by considering whether units had 
permanently shut down, accepted a commitment to permanently shut down 
by 2028, converted to natural gas only, converted to limited use, 
accepted new emission limits, or had existing effective controls such 
that, in all these cases, a full four-factor analysis would likely 
result in a conclusion that no further controls are necessary. For 
units accepting a commitment to permanently shut down by 2028 or to 
comply with new emission limits by 2025, Ohio issued Director's Final 
Findings and Orders (DFFO) and requested they be incorporated into its 
SIP to ensure that the measures become permanent and federally 
enforceable. For units that had already permanently shut down or had 
converted to natural gas or limited use, Ohio ensured measures were 
permanent and federally enforceable through Ohio's permitting process 
under its SIP approved Permit to Install (PTI) program and its title V 
program. Ohio has PTI rules under Ohio Administrative Code (OAC) 
Chapter 3745-31 that have been approved into Ohio's SIP at 40 CFR 
52.1870 as well as a federally approved title V operating permit 
program set forth at 40 CFR part 70. When an owner or operator 
certifies a permanent shutdown and notifies Ohio EPA, the unit cannot 
resume operation without being considered a new source subject to the 
Federal New Source Review (NSR) requirements. Ohio's rules at OAC 3745-
31 prevent installation or

[[Page 71136]]

modification and subsequent operation of a new source without a new 
permit.
    Of the emission units that had already permanently shut down during 
the second implementation period, 12 met Ohio's two-tier Q/d source 
selection criteria. For Conesville Power Plant, coal-fired boiler B007 
permanently shut down on May 31, 2019, and coal-fired boilers B004 and 
B008 permanently shut down on May 31, 2020. DP&L--J.M. Stuart 
Generating Station permanently shut down its coal-fired boiler B001 on 
September 30, 2017, and boilers B002, B003, and B004 on June 1, 2018. 
DP&L--Killen Generating Station also shut down its coal-fired boiler 
B001 on June 1, 2018. W.H. Sammis Plant permanently shut down its coal-
fired boilers B007, B008, B009, and B010 on May 31, 2020.\37\
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    \37\ Each of these units have been certified by the source owner 
or operator as retired under the provisions for Retired Unit 
Exemptions in the Acid Rain Program and/or CSAPR NOX and 
SO2 Trading Programs. The Retired Unit Exemption 
prohibits these units from emitting SO2, NOX, 
or both starting on the day the exemption takes effect. See 40 CFR 
72.8, 40 CFR 97.405, 40 CFR 97.505, 40 CFR 97.605, CFR 97.705, 40 
CFR 97.805. Copies of the Retired Unit Exemption forms for each of 
these units are included in the docket. Also included in the docket 
is a copy of the list of retired generators from the Pennsylvania-
New Jersey-Maryland Interconnection (PJM) Regional Transmission 
Organization (RTO), which includes each of these units as well.
---------------------------------------------------------------------------

    Of the units that met Ohio's Q/d source selection criteria but had 
not yet permanently shut down by Ohio's SIP submittal date in 2021, 3 
units accepted enforceable commitments to permanently shut down by 
2028: Miami Fort Power Station's coal-fired boilers B015 and B016 and 
Zimmer Power Station's coal-fired boiler B006. On September 29, 2020, 
the owner of Miami Fort and Zimmer Power Stations announced plans to 
permanently shut down these units. In lieu of a four-factor analysis, 
Ohio determined that these permanent shutdowns were necessary for 
reasonable progress. As such, on July 9, 2021, Ohio EPA issued DFFOs 
which established enforceable commitments for the shutdown of these 
three units by January 1, 2028, and requested that the DFFOs be 
approved into Ohio's SIP at 40 CFR 52.1870(d) for EPA approved State 
source-specific requirements.\38\
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    \38\ Appendix C of Ohio's July 30, 2021, SIP revision contains 
the DFFOs issued for the Miami Fort and Zimmer Power Stations.
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    Units that met Ohio's Q/d source selection criteria but have since 
converted from coal to natural gas or limited use include the non-EGUs 
at P.H. Glatfelter Company--Chillicothe Facility Units B002 and B003 as 
well as the EGUs at the City of Orrville Department of Public Utilities 
Units B001 and B004. P.H. Glatfelter Company, now Pixelle Specialty 
Solutions LLC, converted units B002 and B003 to natural gas on May 31, 
2016, and September 6, 2016, respectively. The conversions were part of 
a strategy to address BART requirements under the first implementation 
planning period as well as Boiler Maximum Achievable Control Technology 
(Boiler MACT) under permit PTI P0118906. Following the conversions, 
SO2 emissions from P.H. Glatfelter Company units B002 and 
B003 decreased from 2,873 tons per year (tpy) and 5,708 tpy in 2016 to 
1 tpy and 1 tpy in 2018, respectively, and NOX emissions 
decreased from 412 tpy and 691 tpy in 2016 to 134 tpy and 195 tpy in 
2018, respectively. Similarly, the City of Orrville Department of 
Public Utilities converted B004 to natural gas on December 20, 2016, 
and converted B001 to a limited use boiler beginning January 31, 2017, 
to comply with requirements of Boiler MACT and the Data Requirements 
Rule (DRR) for the SO2 NAAQS designation process under 
permit PTI P0124959 and title V Permit No. P0125633. Following the 
conversions, SO2 emissions from B001 and B004 decreased from 
3,846 tpy and 3,030 tpy in 2016 to 275 tpy and 0 tpy in 2018, 
respectively, and NOX emissions decreased from 647 tpy and 
510 tpy in 2016 to 57 tpy and 20 tpy in 2018, respectively. For both 
facilities, reversing the conversion back to coal or fulltime use would 
require approval for a modification of its federally enforceable 
permit.
    Beyond the 15 units shutting down and 4 units converting to natural 
gas or limited use as described above, Ohio EPA also evaluated 13 units 
at 5 facilities for existing effective controls. As explained in EPA's 
July 8, 2021, Clarifications Memo (section 4.1), a ``source's existing 
measures are generally needed to prevent future visibility impairment 
(i.e., to prevent future emission increases) and thus necessary to make 
reasonable progress.'' Measures that are necessary to make reasonable 
progress must be included in the SIP. However, 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 require those measures under the regional haze program in 
its long-term strategy or SIP in order to prevent future emission 
increases.
    The units that Ohio identified with existing effective controls are 
FirstEnergy Generation LLC--Bay Shore Plant Unit B006; Haverhill Coke 
Company LLC Unit P902; and W.H. Sammis Plant Units B011, B012, B013. 
Ohio provided a weight-of-evidence demonstration as each unit has 
consistently implemented their existing measures and have achieved, 
using those measures, a reasonably consistent emission rate. With 
historical data from 2016 through 2019 showing reasonably consistent 
emission rates and 2028 projections from LADCO showing rates consistent 
with 2016, Ohio demonstrated that NOX and SO2 
emission rates for these units are not expected to increase in the 
future. As such, except where expressly noted below for Cardinal Power 
Plant, Ohio Valley Electric Corp.--Kyger Creek Station, and General 
James M. Gavin Power Plant, Ohio determined the existing measures are 
not necessary to make reasonable progress or prevent future emission 
increases and, thus, do not need to be included in the regulatory 
portion of the SIP.
    FirstEnergy Generation LLC--Bay Shore Plant Unit B006 is a 
fluidized bed boiler with limestone injection and a baghouse. The 
operational nature of this process, whereby calcium sulfate is formed 
in the boiler and is captured in the baghouse, results in approximately 
94 percent removal of SO2 and a SO2 emission rate 
of 0.34 pounds per million British thermal units (lbs/MMBtu) or less. 
Unit B006 operates with low combustion temperatures along with very low 
nitrogen content petroleum coke fuel, which have resulted in 
NOX emission rates of 0.08 lbs/MMBtu and less from 2016 to 
2019. The facility's title V permit contains both SO2 and 
NOX emission limits as well as a requirement for 90 percent 
SO2 reduction. Given the reasonably consistent emission 
rates, the permitted emission limitations, and the operational nature 
of the process in which SO2 is inherently controlled and 
NOX has a low formation potential, Ohio determined that B006 
is effectively controlled and that a full four-factor analysis would 
likely result in the conclusion that no further controls are necessary 
for reasonable progress.
    Haverhill Coke Company LLC Unit P902 is a coke battery with 
SO2 controls installed in 2007 with design control 
efficiency of 92 percent. Under the terms of a Federal consent decree 
entered in 2014 and amended in 2018,\39\ portions of which were 
incorporated into the facility's title V permit, Heat Recovery Steam 
Generators were

[[Page 71137]]

installed on P902. This resulted in further SO2 emission 
reductions from 1,183 tpy in 2016 to 777 tpy in 2019. With 
SO2 controls demonstrating greater than 90 percent 
effectiveness, title V permit limits, and consent decree requirements 
resulting in decreasing emissions, Ohio EPA determined that P902 is 
effectively controlled.
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    \39\ United States of America, the State of Illinois and the 
State of Ohio v. Gateway Energy & Coke Company, LLC, Haverhill Coke 
Company, LLC and Suncoke Energy, Inc. (S.D. Illinois Case No. 3:13-
cv-00616-DH-SCW), entered on November 10, 2014, as amended on June 
5, 2015, and July 10, 2018.
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    While W.H. Sammis Plant permanently shut down coal-fired Units 
B007, B008, B009, and B010 in 2020 as noted above, there are three 
remaining coal-fired Units B011, B012, B013 operating with an 
SO2 emission limit of 0.130 lbs/MMBtu under the terms of a 
Federal consent decree,\40\ which was incorporated into the facility's 
title V permit. For NOX control, a selective non-catalytic 
reduction (SNCR) system was installed on B011 in 2006, and selective 
catalytic reduction (SCR) systems with at least 90 percent control 
efficiency were installed on B012 and B013 in 2010, all of which must 
be operated continuously under the Federal consent decree. Flue Gas 
Desulfurization (FGD) systems with 95 percent SO2 control 
efficiency were installed on each unit in 2010. With SO2 and 
NOX controls achieving greater than 90 percent control 
efficiency, title V SO2 permit limits below the 0.2 lbs/
MMBtu limit in the Mercury and Air Toxics Standards for coal-fired 
EGUs, and reasonably consistent emission rates showing no increasing 
future trends, Ohio EPA determined that B012 and B013 are effectively 
controlled as described in the 2019 Guidance. For B011 with a Q/d of 5, 
Ohio determined that although the existing SNCR does not meet the 
examples of in the 2019 Guidance, its year-round operation and an 
emission rate consistently between 0.13 and of 0.15 lbs/MMBtu with no 
future projected increase indicate that a full four-factor analysis 
would likely result in the conclusion that no further controls are 
necessary.
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    \40\ United States of America, et al. v. Ohio Edison Company, et 
al., U.S. District Court for the Southern District of Ohio, Eastern 
Division, Civil Action No. C2-99-1181, entered on March 18, 2005. 
Ohio EPA provided a link to the Consent Decree, a copy of which is 
provided in the docket.
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    Of the 13 units that Ohio initially identified with existing 
effective controls, there were 8 units for which Ohio later provided, 
in its August 6, 2024, supplement, new enforceable measures necessary 
for reasonable progress as described below: Cardinal Power Units B001, 
B002, B009; and Ohio Valley Electric Corp.--Kyger Creek Station Units 
B001, B002, B003, B004, B005.
    Cardinal Power Plant operates three coal-fired boilers: B001, B002, 
and B009. For NOX control, SCRs with approximately 90 
percent control efficiency were installed on all three boilers in 2003. 
The SCRs must be continuously operated under the terms of their PTI 
permits and a Federal consent decree.\41\ From 2016-2019, the SCRs have 
consistently achieved NOX emission rates of 0.09 lbs/MMBtu 
and lower. For SO2 control, FGD systems with approximately 
95 percent control efficiency were installed on B001 in 2008, on B002 
in 2007, and on B009 in 2011. The FGD systems must be operated 
continuously under the terms of the same Federal consent decree that 
were incorporated into their PTI permits. The permitted SO2 
emission limits were set at 1.056 lbs/MMBtu for B001 and B002 as well 
as 0.66 lbs/MMBtu for B009. From 2016-2019, the FGDs have consistently 
achieved SO2 emission rates at or below 0.24 lbs/MMBtu for 
B001, 0.27 lbs/MMBtu for B002, and 0.15 for B009. With FGD systems 
achieving at least 90 percent effectiveness that were installed since 
2007 and emission rates that were reasonably consistent from 2016 to 
2019 with no projected increase, Ohio determined that the units were 
effectively controlled as described in the 2019 Guidance.
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    \41\ United States, et al. v. American Electric Power Service 
Corp., et al., S.D. Ohio Civil Action Nos. C2-99-1250, C2-99-1182, 
C2-05-360, and C2-04-1098 entered on December 10, 2007, and 
substantively modified on July 17, 2019 (AEP Consent Decree). Ohio 
provided a link to the AEP Consent Decree and modification, which 
are included in the docket.
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    Subsequently, on August 6, 2024, Ohio EPA submitted a supplement to 
its July 30, 2021, Regional Haze SIP after going through FLM 
consultation and two public notice and comment periods. Units B001, 
B002, and B009 combined are subject to a SO2 emission limit 
of 4,858.75 lbs/hour as a rolling, thirty-day average that was derived 
as a part of the attainment demonstration for the Steubenville, OH-WV 
2010 1-hour SO2 nonattainment area. The SO2 limit 
became effective on July 5, 2019 and was approved into Ohio`s SIP, 
effective November 21, 2019.\42\ 84 FR 56385, October 22, 2019. Ohio 
EPA submitted its August 6, 2024, supplement to incorporate the 
SO2 limit through a DFFO into the SIP for Regional Haze 
purposes and to ensure reasonable progress by maintaining the existing 
measures.
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    \42\ For the technical justification and development methodology 
behind the SO2 limit, Ohio EPA provided a link to its 
June 2019 Redesignation Request and Maintenance Plan for the Ohio 
Portion of the Steubenville, OH-WV 1-hour SO2 
Nonattainment Area, a copy of which is provided in the docket.
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    Ohio Valley Electric Corp.--Kyger Creek Station operates five coal-
fired boilers: B001, B002, B003, B004, and B005. For SO2 
control, FGD systems operating year-round with 97 percent control 
efficiency were installed on B001 and B002 in 2012 and on B003, B004, 
and B005 in 2011. Under its title V permit, the facility demonstrates 
compliance with the Mercury and Air Toxics Standard through the 
SO2 emission limit of 0.2 lbs/MMBtu. For NOX 
control, SCRs with 70-90 percent efficiency were installed on B001 and 
B002 in 2002 and on B003, B004, and B005 in 2003. Together with 
overfire air systems, the SCRs achieve an average 87 percent 
NOX control efficiency. Ohio EPA recognized that the SCRs do 
not meet the 90 percent control efficiency examples of effectively 
controlled units in the 2019 Guidance and that NOX emission 
control is limited by ammonia slip and mercury oxidation that 
jeopardize compliance with the Mercury and Air Toxics Standards. Since 
Ohio submitted its SIP in 2021, Kyger Creek enhanced its preventative 
maintenance and made process improvements to increase the reliability 
of the urea injection system. This is expected to increase both 
seasonal and year-round NOX removal efficiency. To ensure 
that these recent improvements are sustained going forward, Ohio EPA 
adopted NOX emission limits of 0.4 lbs/MMBtu on a 720-
operating rolling hourly average for each stack: Common Stack 12 for 
combined emissions from B001 and B002 and Common Stack 35 for combined 
emissions from B003, B004, and B005. Both stacks are equipped with 
continuous emissions monitoring systems. The limits were developed by 
analysis of NOX emission rates from 2018 to 2023, prior to 
and following system improvements, and represent a reduction from the 
previous permitted limit of 0.84 lbs/MMBtu. As such, in the supplement 
that Ohio EPA submitted on August 6, 2024, Ohio requested to 
incorporate the new NOX emission limit of 0.4 lbs/MMBtu for 
both Common Stacks 12 and 35 into Ohio's SIP at 40 CFR 52.1870(d) 
through a DFFO for Regional Haze purposes to ensure reasonable progress 
by maintaining the recent improvements.
    After refining the list of 38 units identified by Ohio's Q/d source 
selection threshold and addressing 32 of those as described above, Ohio 
EPA provided four-factor analyses for the remaining 6 units at the 
following 4 facilities: Avon Lake Power Plant Unit B012; Carmeuse Lime, 
Inc.--Maple Grove Operations Units P003 and P004; Dover Municipal Light 
& Power Plant

[[Page 71138]]

Unit B004; and General James M. Gavin Power Plant Units B003 and B004. 
The emission units that Ohio selected for a four-factor analysis are 
described below.
    Consistent with the first regional haze implementation period, Ohio 
EPA focused on NOX and SO2 emissions in 
considering potential additional control measures at these four 
facilities. As demonstrated by the analysis in LADCO's Technical 
Support Document of the IMPROVE monitoring data, the NOX and 
SO2 emissions lead to the formation of the particulate 
species of nitrate and sulfate that currently contribute more to 
visibility impairment in the LADCO Class I Areas than PM2.5, 
NH3, and VOC. The LADCO Class I Areas consist of Boundary 
Waters Canoe Area Wilderness and Voyageurs National Park in Minnesota, 
as well as Isle Royale National Park and Seney Wilderness Area in 
Michigan. Additionally, in Table 20 of its submittal, Ohio EPA provided 
2017 NEI data for Ohio point sources, showing smaller VOC, PM, and 
NH3 emissions relative to NOX and SO2 
emissions. For this reason, Ohio EPA chose to focus on reducing 
emissions of NOX and SO2, which the 2019 Guidance 
recommended would be a reasonable approach for the second 
implementation period. See 2019 Guidance at page 12. Nevertheless, Ohio 
considered emissions from each of the regional haze precursors 
NOX, SO2, PM2.5, NH3 and 
VOC in the source selection process. As shown in Table 4 of its 
submittal, the sources meeting Ohio's primary and secondary Q/d 
selection criteria account for 38 units at 16 facilities, representing 
80 percent of SO2 emissions, 57 percent of NOX 
emissions, 47 percent of PM2.5 emissions, and 23 percent of 
NH3 emissions for all sources with a sum of SO2, 
NOX, PM2.5, and NH3 emissions from 
2016 greater than 0.1 tpy. The background on each of the 6 units 
selected for a four-factor analysis is described below.
Avon Lake Power Plant
    Avon Lake Power Plant is an EGU, and Unit B012 is a 6,040 MMBtu/
Hour pulverized coal-fired boiler that was installed in 1970. For 
NOX control, B012 is equipped with low-NOX cell 
burners and overfire air. For SO2 control, Avon Lake Power 
Plant accepted a federally enforceable SO2 emissions limit 
of 9,600 lbs/hr on a 1-hour average basis for all SO2-
emitting sources at the facility (B010, B012, B013, B015, and B016) to 
satisfy requirements under the DRR for the 2010 SO2 NAAQS 
designation process.\43\ See 83 FR 40723, August 16, 2018. The 
facility's title V permit P0085253, effective April 18, 2017, contains 
a SO2 permit limit for B012, which was reduced from the 
previous limit of 4.65 lbs/MMBtu to a new combined SO2 
permit limit on B010 and B012 of 1.59 lbs/MMBtu as a rolling, 30-day 
average. To comply with the new SO2 emissions limits, the 
facility switched to a blend of Western Bituminous and Powder River 
Basin coal in 2016, which contributed to reductions in annual 
SO2 emissions for B012 from 8,862 tpy in 2016 to 1,597 tpy 
in 2019, lowered the SO2 emission rate from 1.60 lbs/MMBtu 
in 2016 to 0.70 lbs/MMBtu in 2019, and reduced Q/d from 32 in 2016 to 7 
in 2019.
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    \43\ Ohio's January 13, 2017, submittals for the 2010 
SO2 NAAQS DRR describing the AERMOD Modeling Results for 
Avon Lake Power Plant with the derivation of the limits of 1.59 lbs/
MMBtu and 9,600 lbs/hour as the resulting critical emissions value 
is available at https://www.epa.gov/so2-pollution/so2-data-requirements-rule-january-13-2017-state-submittals-ohio.
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Carmeuse Lime, Inc.--Maple Grove Operations
    Carmeuse Lime, Inc.--Maple Grove Operations is a lime manufacturing 
plant. Unit P003 and Unit P004 both consist of a rotary kiln and cooler 
as well as a shared stack for emissions. P003 and P004 burn coal, 
petroleum coke, and/or natural gas. For PM control, both units have 
baghouses, however, there are no add-on controls for SO2 or 
NOX. Although both units were subject to a best available 
control technology analysis under the Federal PSD program in 2002-2003 
when lime manufacturing operations were restarted, no add-on control 
technologies for NOX or SO2 were found to be 
cost-effective. However, SO2 at both units is inherently 
controlled when calcium-rich lime kiln dust chemically absorbs the 
SO2 in the flue gas, which is then removed in the baghouse. 
NOX emissions at both units are controlled by good 
combustion practices.
    Limits on SO2 and NOX are included in the 
facility's title V Permit P0125171. The permit includes a maximum 
sulfur content limit for fuel of 5.50 percent for coal and 6.50 percent 
for coke by weight. P003 and P004 are subject to SO2 limits 
of 1,102 lbs/hour and 4,826.80 tons per rolling, 12-month period. P003 
and P004 are also subject to NOX limits of 1,234.90 lbs/hour 
and 5,408.90 tons per rolling 12-month period.
Dover Municipal Light & Power Plant
    Dover Municipal Light & Power Plant is a coal-fired electrical 
generating plant. Unit B004 is a 247 MMBtu/hour coal-fired stoker 
boiler that was installed in 1962 that uses natural gas as a backup 
fuel. Under title V Permit P0090810, B004 is subject to SO2 
emissions limit of 4.60 lbs/MMBtu.
General James M. Gavin Power Plant
    General James M. Gavin Power Plant is a coal-fired electrical 
generating plant. Unit B003 and Unit B004 are both 11,936 MMBtu/hr 
pulverized coal-fired, dry-bottom boilers installed in 1974. For 
SO2, wet FGD systems with 95 percent control efficiency were 
installed on B003 in 1994 and on B004 in 1995. NOX emissions 
for B003 and B004 are controlled through the use of low NOX 
burners and SCR, achieving 91 percent control efficiency. The FGDs and 
SCRs are operated continuously under the terms of the facility's title 
V Permit P0089258 and the Federal AEP Consent Decree. A federally 
enforceable SO2 emission limit of 7.41 lbs/MMBtu applies to 
both B003 and B004 under the title V permit. From 2016 to 2019, 
SO2 emission rates have ranged from 0.27 to 0.37 lbs/MMBtu 
for B003 and 0.29 to 0.39 lbs/MMBtu for B004, while NOX 
emission rates have remained between 0.10 and 0.11 for both units 
during the same time period.
2. Emission Measures Necessary To Make Reasonable Progress
    The provisions of 40 CFR 51.308(f)(2)(i) require States to evaluate 
and determine the emission reduction measures that are necessary to 
make reasonable progress by applying the four statutory factors to 
sources in a control analysis. The emission reduction measures that are 
necessary to make reasonable progress must be included in the long-term 
strategy. 40 CFR 51.308(f)(2).
    Ohio EPA's four-factor analyses are described below for each of the 
6 units identified through its Q/d source selection process. This 
includes units that had not already permanently shut down, accepted an 
enforceable commitment to permanently shut down or comply with new 
limits, converted to natural gas or limited use, or had existing 
effective controls.
Avon Lake Power Plant
    Avon Lake Power Plant Unit B012 was selected for a four-factor 
analysis based on 2016 emissions resulting in a Q/d of 32. Avon Lake 
evaluated B012 for both NOX and SO2 controls.
    Avon Lake evaluated wet FGD and a spray dryer absorber (SDA) for 
SO2 control. Capital costs were estimated at $417,000,000 
for SDA and $483,000,000 for wet FGD. Annual operating costs

[[Page 71139]]

were estimated at $44,500,000 for SDA and $51,600,000$ for wet FGD. 
Based on a remaining useful life of either 20 or 30 years and retrofit 
factors of 1.2 and 1, the cost effectiveness was estimated at $19,500/
ton and $22,600/ton for wet FGD for 2,284 tpy in potential emission 
reductions from either control option.
    For NOX control, Avon Lake evaluated SNCR and SCR with 
capital costs ranging from $13,000,000 for SNCR to $191,000,000 for 
SCR, while annual operating costs were estimated at $1,679,100 for SNCR 
and $25,600,000 for SCR. Cost effectiveness was estimated at $10,200/
ton for SNCR for 164 tpy in potential emission reductions and $26,700/
ton for SCR for 959 tpy in reductions. Installation time was estimated 
at 5 years for SO2 controls and 2 to 5 years for SNCR and 
SCR, respectively. Impacts from energy requirements, solid waste, and 
ammonia usage were also evaluated.
Carmeuse Lime, Inc.--Maple Grove Operations
    Carmeuse Lime, Inc.--Maple Grove Operations Units P003 and P004 
were selected for a four-factor analysis.
    The evaluation of SO2 controls at Units P003 and P004 
included conditioning tower slurry injection, DSI, and wet scrubbers. 
Capital costs for each unit were estimated at $14,437,783 for 
conditioning tower slurry injection, $16,960,653 for DSI, and 
$23,784,927 for wet scrubbers. Annual costs were estimated at 
$3,982,597 for conditioning tower slurry injection, $9,140,819 for DSI, 
and $6,305,184 for wet scrubber. The cost effectiveness values at Units 
P003 and P004, respectively, were estimated for conditioning tower 
slurry injection at $3,266 and $3,274/ton, DSI at $5,857 and $5,862/
ton, and wet scrubbing at $4,506 and 4,043/ton SO2. 
Potential SO2 emission reductions for each unit P003 and 
P004, respectively, were 1,221 and 1,216 tpy for conditioning tower 
slurry injection, 1,566 and 1,559 tpy for DSI, and 1,559 and 1,559 tpy 
for wet scrubbing.
    Switching fuel to solely natural gas was also evaluated and found 
to be technically infeasible due to the insufficient supply of natural 
gas in the region as well as the impact on the production process that 
would result from altering the product chemistry and capacity. The 
switch to natural gas would fundamentally change the production process 
since the flame temperature would be lower, altering product chemistry 
and quality, changing the thermal profile of the kiln, and reducing 
production capacity.
    For NOX, several control options were evaluated, 
including preheater installation, low-NOX burners, SCR, and 
SNCR. However, no options were determined to be technically feasible 
beyond current operation under good combustion practices. Despite the 
concerns about technical feasibility, Carmeuse Lime, Inc.--Maple Grove 
Operations performed a four-factor analysis on the addition of tail-end 
SCR, which would have required the installation of an SO2 
wet scrubber upstream and stack gas reheat downstream. Estimated 
capital costs for Units P003 and P004 were $16,878,012 and $16,722,674, 
respectively, while estimated annual costs were $11,596,001 and 
$11,431,638, resulting in cost effectiveness values of $10,419 and 
$11,484/ton NOX.
    Both SO2 and NOX analyses considered a 
remaining useful life of 20 or 25 years, a 4 to 5 year installation 
time, and energy and non-air quality environmental impacts. In addition 
to the consideration of candidate control options, Carmeuse Lime, 
Inc.,--Maple Grove Operations considered visibility impact and noted 
that an analysis done during the first implementation period shows that 
the facility is located outside the area of influence for the closest 
Class I area, the Dolly Sods Wilderness Area, and that it was not one 
of the four sources in Ohio identified by VISTAS in their June 22, 
2020, request as a source that strongly contributes to regional haze.
Dover Municipal Light & Power Plant
    Dover Municipal Light & Power Plant Unit B004 was selected for a 
four-factor analysis based on 2016 emissions resulting in a Q/d of 7 
and the absence of existing SO2 add-on controls. The unit is 
controlled with a baghouse for PM, activated carbon for mercury, and 
DSI for hydrogen chloride.
    The evaluation of SO2 controls considered fuel 
switching, DSI, wet FGD, and SDA. The City of Dover determined that 
switching from the current low sulfur coal to natural gas was 
infeasible, not only because it would require major changes to the 
boiler's burner design and an additional mile of natural gas pipeline, 
but also because of the insufficiency of a natural gas supply. For the 
other control options, capital costs were estimated at $2,640,000 for 
DSI, $28,110,269 for wet FGD, and $24,274,288 for SDA. Annual costs 
were estimated at $1,558,509 for DSI, $4,615,991 for wet FGD, and 
$4,030,803 for SDA. The cost effectiveness and potential reductions in 
SO2 emissions were estimated at $2,985/ton for 522 tpy with 
DSI, $5,016/ton for 920 tpy with wet FGD, and $4,402/ton for 916 tpy 
with SDA.
    The analyses considered a remaining useful life of 30 years, a 5-
year installation time, as well as energy and non-air quality 
environmental impacts. Dover Municipal Light & Power Plant also 
compared annualized compliance costs as a percentage of sales for each 
control option, which resulted in 6.2 percent for DSI and 18.5 percent 
for wet FGD. Citing to guidance for the Regulatory Flexibility Act,\44\ 
Dover Municipal Light & Power Plant observed that EPA has employed 
discretion in not proceeding with rulemakings that regulate only a 
small number of small businesses with annualized compliance costs as a 
percentage of sales greater than 3 percent. As such, Dover Municipal 
Power & Light Plant noted that as a non-profit governmental 
organization, the costs of any of the controls evaluated would threaten 
the viability of the plant, with the options of wet FGD and SDA almost 
certainly resulting in closure.
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    \44\ EPA Office of Policy, Economic and Innovation, ``Final 
Guidance for EPA Rulewriters: Regulatory Flexibility Act as Amended 
by the Small Business and Regulatory Enforcement Fairness Act,'' 
November 30, 2006.
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General James M. Gavin Power Plant
    General James M. Gavin Power Plant was selected for a four-factor 
analysis based on 2016 emissions resulting in a Q/d above Ohio's 
threshold for Units B003 and B004 as well as the relative impact of 
this source on visibility impairment.
    For NOX, Ohio EPA determined that the units were 
effectively controlled. This determination considered that the SCRs 
were installed in 2001, are operated continuously, and achieve 91 
percent control efficiency with low NOX burners. In 
addition, Ohio found that the emission rates, which ranged between 0.10 
and 0.11 lbs/MMBtu from 2016 to 2019, were reasonably consistent and 
that no increase in those rates was projected into 2028.
    SO2 was considered in the four-factor analysis since the 
current FGDs were installed in 1994-1995 before the beginning of the 
first implementation period. General James M. Gavin Power Plant 
evaluated fuel switching, retrofitting new dry FGD, retrofitting new 
wet FGD, and making operational improvements to the existing wet FGD. 
General James M. Gavin Power Plant currently burns eastern bituminous 
coal with a sulfur content of 3.9 to 4.2 percent. Switching to lower 
sulfur coal was considered technically infeasible due to operational 
issues from a higher ash content causing slagging issues and 
overburdening the electrostatic precipitator (ESP), thereby decreasing

[[Page 71140]]

its control efficiency. Switching to natural gas was precluded since 
natural gas is not currently available at the site, and the nearest 
pipeline 10 miles away does not have the capacity to supply the 
required loading to the plant.
    In terms of add-on SO2 controls, the existing DSI 
systems designed for SO3 emissions control were evaluated 
for collateral removal of SO2. However, the analysis 
determined that modifying operational parameters with higher sorbent 
injection rates required for significant SO2 emissions 
control would overburden the ESP in handling particulate emissions. 
Similarly, the analysis found that installation of a new SDA would 
require replacing the existing ESP and would offer no advantage 
compared to the existing wet FGD. In 2019, General James M. Gavin Power 
Plant made significant expenditures to upgrade and optimize the 
existing wet FGD systems which improved control efficiency to 95 
percent. With the significant recent expenditures for the upgrades and 
the lack of technically feasible options for further optimization, the 
analysis cited to the 2019 Guidance in determining that replacing the 
existing wet FGD was not a practical option and that additional 
controls were unlikely to be reasonable. See 2019 Guidance at 22-23.
    In December 2023, General James M. Gavin Power Plant provided to 
Ohio EPA a supplemental analysis with new information on $9.3 million 
in additional upgrades and improvements to their FGD systems made since 
2020, many of which occurred after Ohio EPA submitted its Regional Haze 
SIP in July 2021. Additionally, General James M. Gavin Power Plant 
evaluated whether the facility could, at a reasonable cost, achieve a 
consistently lower SO2 emission rate either through existing 
measures or potential low-cost upgrades. Although no additional 
upgrades were found to be feasible based on the custom-build nature of 
the FGD systems and the recent improvements, General James M. Gavin 
Power Plant identified the feasibility of consistently achieving a 
lower SO2 emission rate as a result of the recent upgrades 
based on 2019-2023 emissions data, load variability, coal content and 
supply. To ensure that the recent improvements are maintained going 
forward, Ohio adopted new SO2 emission limits of 0.75 lbs/
MMBtu on a rolling 30-operating day average for both B003 and B004, 
representing a reduction from the former SO2 limits of 7.41 
lbs/MMBtu. To ensure the new SO2 limits are permanent and 
federally enforceable, Ohio EPA submitted the August 6, 2024, 
supplement to incorporate the new SO2 limits through a DFFO 
into the SIP at 40 CFR 52.1870(d) for Regional Haze purposes.
Ohio's Evaluation of the Four-Factor Analyses
    In considering the four-factor analyses for each of the four 
facilities described above, Ohio determined that additional add-on 
controls are not cost-effective and thus not necessary for reasonable 
progress in the second planning period. In making its determination, 
Ohio evaluated the analyses of energy and solid waste impacts from 
increased power usage and generation of solid waste and wastewater. 
Ohio evaluated capital and operating costs, costs per ton of pollutant 
removed, and potential emission reductions, and took under 
consideration compliance costs/sales ratios. To compare the candidate 
control options at a facility, Ohio estimated the visibility benefit of 
potential emission reductions as a part of a weight-of evidence 
approach to be considered alongside, not instead of, the four statutory 
factors. In determining the maximum visibility benefit at any Class I 
area in 2028, Ohio used source apportionment modeling conducted by 
VISTAS \45\ and scaled the modeled visibility impacts to the expected 
emissions reductions from the potential controls evaluated, which 
ranged from 0.001 to 0.180 Mm-1 at Avon Lake Power Plant, 
0.192 to 0.246 Mm-1 at Carmeuse Lime, Inc.--Maple Grove, and 
0.041 to 0.072 Mm-1 at Dover Municipal Power & Light Plant. 
Ohio also pointed to the State's progress report in its regional haze 
SIP revision for the seconding planning period, showing emission trends 
with significant reductions of 90 percent SO2 and 57 percent 
NOX from 2005 to 2017. Looking forward to 2028, Ohio 
identified additional emission reductions that will be achieved in the 
second planning period through measures identified in the long-term 
strategy, which are discussed below.
---------------------------------------------------------------------------

    \45\ ``The VISTAS Regional Haze Project,'' https://metro4-sesarm.org/content/vistas-regional-haze-program; ``Task 7--PSAT 
Source Apportionment Modeling/Tagging,'' https://www.metro4-sesarm.org/content/task-7-source-apportionment-modelingtagging; 
``PSAT Source Apportionment Modeling Results Report--August 2020,'' 
https://www.metro4-sesarm.org/sites/default/files/VISTAS%20Task%207%20PSAT_20200831.pdf.
---------------------------------------------------------------------------

    Ohio concluded that on-the-books and on-the-way controls identified 
in the State's long-term strategy, including the DFFOs for permanent 
shutdowns at Miami Fort Power Plant and Zimmer Power Station as well as 
the DFFOs for SO2 and NOX limits at Cardinal 
Power Plant, General James M. Gavin Power Plant, and Ohio Valley 
Electric Corp.--Kyger Creek, are necessary to achieve reasonable 
progress at the Class I areas impacted by emissions from Ohio.
3. Ohio's Long-Term Strategy
    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). After 
considering information regarding existing effective controls, analyses 
under the four statutory factors in 40 CFR 51.308(f)(2)(i), and the 
five additional factors in 40 CFR 51.308(f)(2)(iv) in addition to other 
requirements in 40 CFR 51.308(f)(2)(ii) described below, Ohio 
determined the State's long-term strategy for the second implementation 
planning period is comprised of the following measures to make 
reasonable progress.\46\ These measures represent reductions beyond 
those planned in the first implementation planning period with numerous 
changes in emissions and emission limits since the first implementation 
planning period, as well as emission reductions due to ongoing air 
pollution control programs and permanent shutdowns. Except as noted 
below for the DFFOs and Ohio's Beneficiary Mitigation Plan for the 
Volkswagen Settlement, the following measures in Ohio's long-term 
strategy are already permanent and federally enforceable. Ohio EPA 
requested that the DFFOs be incorporated into the regulatory portion of 
Ohio's SIP at 40 CFR 52.1870(d) to ensure that they will also be 
federally enforceable and permanent for regional haze purposes.
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    \46\ The measures listed in Ohio's long-term strategy are 
described in Ohio's SIP submission in Section III.3(e)(5) and 
III.5(e).
---------------------------------------------------------------------------

    On-the-books controls for the long-term strategy in the 2nd 
implementation period include:

 Permanent shutdown of Conesville Power Plant Units B004, B007, 
and B008
 Permanent shutdown of DP&L J.M. Stuart Units B001, B002, B003, 
and B004
 Permanent shutdown of DP&L J.M. Killen Unit B001
 Permanent shutdown of W.H. Sammis Plant Units B007, B008, 
B009, and B010
 National Emission Standards for Hazardous Air Pollutants 
(NESHAP) for Reciprocating Internal Combustion Engines
 Control of Hazardous Air Pollutants from Mobile Sources (also 
known as the Federal Mobile Source Air Toxics Rules)

[[Page 71141]]

 Mercury and Air Toxics Standards (40 CFR 63, subpart UUUUU)
 Federal Oil and Natural Gas Industry Standards
 NOX Emission Standards for New Commercial Aircraft 
Engines (40 CFR 87, 40 CFR 1068)
 NESHAPs for Industrial, Commercial, and Institutional Area 
Source Boilers, Major Source Boilers (40 CFR 63)
 New Source Performance Standards (NSPS) for Commercial and 
Industrial Solid Waste Incinerators (CISWI) (40 CFR 60, subpart CCCC, 
40 CFR 60, subpart DDDD)
 NSPS for New Residential Wood Heaters (40 CFR 60, subpart AAA)
 SO2 Data Requirements Rule (40 CFR 51)
 Ohio's Beneficiary Mitigation Plan for the Volkswagen 
Settlement (84 FR 43508, August 21, 2019)

    On-the-way controls for the long-term strategy that reflect 
additional emission reductions expected by 2028 include:

 Revised CSAPR Update (40 CFR 97, subpart GGGGG)
 DFFO for Miami Fort Power Station, providing for the permanent 
shutdown of coal-fired Boilers B015 and B016, and for Zimmer Power 
Station, providing for the permanent shutdown of coal-fired Boiler B006
 DFFO for Cardinal Power Plant, providing for an SO2 
emission limit on coal-fired Boilers B001, B002, and B009
 DFFO for Ohio Valley Electric Corp.--Kyger Creek, providing 
for a new NOX emission limit on coal-fired Boilers B001, 
B002, B003, B004, and B005
 DFFO for General James M. Gavin Power Plant, providing for a 
new SO2 emission limit on coal-fired Boilers B003 and B004
4. EPA's Evaluation of Ohio's Compliance With 40 CFR 51.308(f)(2)(i)
    EPA proposes to find that Ohio has satisfied the requirements of 40 
CFR 51.308(f)(2)(i) related to evaluating sources and determining the 
emission reduction measures that are necessary to make reasonable 
progress by considering the four statutory factors. Ohio's selection of 
sources and evaluation of control measures was reasonable and 
consistent with the requirements of 40 CFR 51.308(f)(2)(i).
    For Ohio's source selection methodology, Ohio EPA targeted the 
sources with the highest potential to impair visibility at mandatory 
Class I areas. Ohio EPA included a thorough description of its source 
selection methodology. Starting with LADCO's calculations for Q/d based 
on 2016 data, Ohio EPA compared more recent point source inventories 
from the 2017 NEI and 2018 Ohio EIS to determine if updated Q/d values 
on a unit basis would identify additional sources for selection. Then, 
in response to other methods used by NPS and USFS to identify sources 
for further evaluation, Ohio EPA modified its source selection process 
by adding a secondary criterion for a facility-wide Q/d. Ohio EPA's 
two-tiered approach broadened its source selection process and 
identified individual units with a Q/d greater than 5 as well as units 
with a Q/d greater than 4 at facilities with a Q/d greater than 10. 
Using this source selection methodology, Ohio EPA selected 38 units at 
16 facilities for further analysis, accounting for 80 percent of 
SO2 and 57 percent of NOX for point sources with 
Q greater than 0.1 tpy.
    In determining which facilities to evaluate through a four-factor 
analysis, Ohio EPA refined the list of sources selected using its Q/d 
thresholds by providing adequate justification for no further analysis 
where sources had accepted an enforceable commitment for SO2 
or NOX limits, permanently shut down, accepted an 
enforceable commitment to permanently shut down by 2028, converted to 
natural gas or limited use, or had existing effective controls.
    For selected sources that had accepted an enforceable commitment 
for SO2 or NOX limits, Ohio issued DFFOs to be 
incorporated into its SIP at 40 CFR 52.1870(d) for 10 units at 3 
facilities: Cardinal Power Units B001, B002, and B009; Ohio Valley 
Electric Corp.--Kyger Creek Station Units B001, B002, B003, B004, and 
B005; and General James M. Gavin Power Plant Units B003 and B004. These 
limits in the DFFOs ensure recent improvements in emission controls are 
maintained and that the measures are permanent and federally 
enforceable for regional haze purposes.
    For selected sources that had permanently shut down or had accepted 
an enforceable commitment to permanently shut down by 2028, Ohio 
identified 15 units at 6 facilities: Conesville Power Plant Units B004, 
B007, and B008; DP&L J.M. Stuart Units B001, B002, B003, and B004; DP&L 
JM Killen Unit B001; W.H. Sammis Plant Units B007, B008, B009, and 
B010; Miami Fort Power Station Units B015 and B016; and Zimmer Power 
Station Unit B006. Based on 2016 inventories, the permanent shutdown of 
these units represents federally enforceable and permanent emission 
reductions from some of Ohio's largest sources as follows. In 2019 and 
2020, the shutdowns at Conesville Power Plant Units B004, B007, and 
B008 achieved emission reductions of 5,013 tpy SO2 and 5,981 
tpy NOX. In 2017 and 2018, the shutdowns at DP&L, J.M. 
Stuart Generating Station achieved emission reductions of 9,005 tpy 
SO2 and 5,466 tpy NOX. In 2018, the shutdown at 
DP&L, Killen Generating Station achieved emission reductions of 10,130 
tpy SO2 and 6,057 tpy NOX. In 2020, the shutdowns 
at W.H. Sammis Plant achieved reductions of 2,996 tpy SO2 
and 1,634 NOX. By 2028, under the DFFOs, the shutdowns at 
Miami Fort Power Station will achieve emission reductions of 10,214 tpy 
SO2 and 5,052 tpy NOX, while the shutdown at 
Zimmer Power Station will achieve emission reductions of 9,973 tpy 
SO2 and 5,458 tpy NOX. Together, these shutdowns 
will reduce SO2 by over 47,000 tpy and NOX by 
over 33,000 tpy and represent emission reductions of 32 percent 
SO2 and 32 percent NOX from all point sources in 
Ohio with total emissions of SO2, NOX, PM, and 
NH3 greater than 0.1 tpy based on 2016 emissions.
    For selected sources that converted to natural gas or limited use 
under enforceable permit conditions, Ohio identified conversions at 4 
units within 2 facilities, where add-on controls or more stringent 
limits would not be necessary for reasonable progress. Compared to 2016 
base-year emissions, the conversions at the City of Orrville Department 
of Public Utilities Units B001 and B004 reduced SO2 
emissions by 6,601 tpy, and the conversations at P.H. Glatfelter 
Company--Chillicothe Facility B002 and B003 reduced SO2 
emissions by 8,579 tpy. Together, in addition to the emission 
reductions from the shutdowns mentioned above, these conversions 
represent an additional 10 percent reduction in SO2 
emissions from all point sources in Ohio with total emissions of 
SO2, NOX, PM, and NH3 greater than 0.1 
tpy.
    For selected sources that had existing effective controls, Ohio 
sufficiently provided a weight-of-evidence demonstration as described 
in the 2021 Clarifications Memo for 5 units at 3 facilities: 
FirstEnergy Generation LLC--Bay Shore Plant Unit B006; Haverhill Coke 
Company LLC Unit P902; and W.H. Sammis Plant Units B011, B012, B013. 
Ohio documented that these units are effectively controlled for 
SO2 and NOX by inherent process or control 
systems installed during the first implementation period with greater 
than 90 percent control efficiency as well as federally enforceable 
limits in Federal consent decrees or limits below levels recommended in 
the 2019 Guidance as potentially existing effective controls. With 
reasonably

[[Page 71142]]

consistent trends in emission rates, Ohio also adequately demonstrated 
that the existing measures for these units are not necessary to make 
reasonable progress or prevent future emission increases and, thus, do 
not need to be included in the regulatory portion of the SIP.
    Of all the 38 emission units Ohio identified through its Q/d source 
selection process listed above, Ohio relied upon the following specific 
control measures at 25 units in its long-term strategy in addition to 
the other Federal regulations and State programs included. For 12 of 
those units, Ohio's long-term strategy relies upon permanent shutdowns 
that have already occurred during the 2nd implementation period. For 
the other 13 units, Ohio EPA provided DFFOs with enforceable 
commitments for either SO2 limits or NOX limits 
by 2025 or permanent shutdowns by 2028 to be incorporated into Ohio's 
SIP for regional haze purposes at 40 CFR 52.1870(d).
    For the remaining 13 emission units that Ohio EPA identified 
through its Q/d source selection process, Ohio did not rely on new or 
existing measures as part of the long-term strategy to make reasonable 
progress in the second planning period. At 4 of those units, Ohio EPA 
documented enforceable conversions to natural gas or limited use. At 
another 5 of those units, Ohio provided a weight of evidence 
demonstration and determined their existing measures are not necessary 
to make reasonable progress or prevent future emission increases. At 
the other 4 units, Ohio provided four-factor analyses. Each of these 
analyses considered all four statutory factors and appropriately 
followed the methods in the EPA Air Pollution Control Cost Manual.\47\ 
The lowest cost control options in the four-factor analyses outlined 
the potential for emission reductions at each unit for Avon Lake Power 
Plant of 2,284 tpy SO2 for $19,500/ton, Dover Municipal 
Power & Light Plant of 522 tpy SO2 for $2,985/ton, and at 
Carmeuse Lime, Inc.--Maple Grove Operations of 1,221 and 1,216 tpy 
SO2 for $3,226/ton and $3,274/ton, respectively. With the 
emission reductions from already implemented shutdowns and fuel 
conversions, Ohio made a reasoned determination that additional add-on 
controls are not cost effective and thus not necessary for reasonable 
progress in the second planning period.
---------------------------------------------------------------------------

    \47\ See EPA Air Pollution Control Cost Manual, available at 
https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution.
---------------------------------------------------------------------------

    The permanent shutdown of 15 units at 6 large EGUs during the 
second implementation period represents large enforceable reductions in 
SO2 and NOX from Ohio sources that had impacted 
the same Class I areas that are impacted by the 4 units evaluated in 
the four-factor analyses. With a relatively small potential for 
additional emission reductions identified in the four-factor analyses 
compared to those of the shutdowns and fuel conversions already taking 
place, Ohio EPA provided a reasoned basis for its conclusions to not 
require additional controls at those 4 units for the second 
implementation period.
    Overall, 29 out of 38 coal-fired units above Ohio's Q/d threshold 
either converted to natural gas or limited use, accepted enforceable 
limits, or have or will permanently shut down by 2028. The trends in 
NOX and SO2 emissions noted in Ohio's progress 
report discussed below demonstrate how Ohio's long-term strategy will 
continue to make significant reductions during the second 
implementation period. The shutdowns will reduce statewide 
SO2 by over 47,000 tpy and NOX by over 33,000 
tpy, and the conversions to natural gas add another 15,000 tpy of 
SO2 reductions to that total. Together, these shutdowns and 
fuel conversions represent statewide emission reductions of 43 percent 
SO2 and 32 percent NOX from point sources in Ohio 
with total emissions of SO2, NOX, PM, and 
NH3 greater than 0.1 tpy based on 2016 emissions. Ohio's 
plan shows that these measures will achieve substantial SO2 
and NOX emission reductions beyond those included in its 
first implementation period. These shutdowns, conversions, and 
committed controls contribute to Ohio's emission reductions and the 
associated visibility improvements at the affected Class I areas for 
the second implementation planning period.
    EPA proposes to find that the shutdowns and conversions noted above 
that have already taken place during the second planning period are 
already federally enforceable and permanent and do not need to be 
included in the regulatory portion of the SIP. For the upcoming 
permanent shutdowns and committed controls provided for in the DFFOs, 
EPA proposes to find that those are necessary for reasonable progress 
and must be included in the SIP and made federally enforceable and 
permanent. For the other 9 coal-fired units, Ohio EPA determined that 
no additional controls would be necessary for reasonable progress in 
the second planning period based on existing effective controls that 
have achieved reasonably consistent emission rates that are not 
expected to increase in the future.
    EPA proposes to find that Ohio has satisfied the requirements of 40 
CFR 51.308(f)(2)(i) related to evaluating sources and determining the 
emission reduction measures that are necessary to make reasonable 
progress by applying the four statutory factors to sources in a control 
analysis. Ohio EPA's SIP submission, as supplemented, reasonably 
applied the Q/d source selection process in relying on the closest 
Class I areas and the emissions of NOX, SO2, 
PM2.5, NH3 and VOC. Ohio EPA examined a 
reasonable set of sources, including sources identified by FLMs. In 
addition, Ohio EPA adequately explained its decision to focus on the 
two pollutants--SO2 and NOX--that currently drive 
visibility impairment within the LADCO region. EPA proposes to find 
that Ohio EPA adequately supported its conclusions for its top-
impacting sources in determining permanent and federally enforceable 
shutdowns, controls, and fuel conversions necessary for reasonable 
progress. EPA is basing this proposed finding on the State's 
examination of its largest operating EGU and non-EGU sources. EPA 
proposes to find the State's approach reasonable because it 
demonstrated that these sources with the greatest modeled impacts on 
visibility, as well as other sources above the State's Q/d threshold 
that might be expected to impact visibility, either have shut down, 
accepted an enforceable commitment to shut down by 2028, accepted new 
emission limits by 2025, converted to natural gas or limited use, or 
have existing effective controls.
    As part of the State's long-term strategy, Ohio EPA submitted 4 
DFFOs providing legally binding, enforceable commitments upon the 
owners or operators of the facilities, and any subsequent owner or 
operator, at the State level under Ohio Revised Code 3704.03 and 
3745.01. Since Ohio is relying on these 4 DFFOs to make reasonable 
progress as part of its long-term strategy for the second 
implementation period, Ohio EPA requested the incorporation of the 
DFFOs into the Ohio SIP to ensure that they are federally enforceable 
and permanent for regional haze purposes. The first DFFO was effective 
on July 9, 2021, and provides for the shutdown of Miami Fort Power 
Station Units B015 and B016 and Zimmer Power Station Unit B006 by no 
later than January 1, 2028. The other three DFFOs provide for

[[Page 71143]]

SO2 emission limits at Cardinal Power Plant Units B001, 
B002, and B009 and General James M. Gavin Power Plant Units B003 and 
B004 as well as a NOX emission limit Ohio Valley Electric 
Corp.--Kyger Creek Units B001, B002, B003, B004, and B005. These three 
DFFOs became effective July 26, 2024, when they were entered into the 
Ohio EPA Director's journal, and compliance begins on January 1, 2025. 
Based on the discussion herein, these 4 DFFOs provide an adequate 
technical and legal basis for source-specific measures that are 
consistent with the CAA requirements and EPA's Regional Haze Rule. As 
such, EPA proposes to approve Ohio EPA's request and incorporate by 
reference these 4 DFFOs into the SIP.
5. Consultation With States
    The consultation requirements of 40 CFR 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. The provisions of 40 CFR 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. The provisions of 40 CFR 
51.308(f)(2)(ii)(C) speak to what happens if States cannot agree on 
what measures are necessary to make reasonable progress. States may 
satisfy the requirement of 40 CFR 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.
    Although Ohio has no mandatory Class I Federal areas within its 
borders, Ohio has previously been shown to have sources with emissions 
that impact visibility at downwind mandatory Class I Federal areas. 
Ohio EPA consulted with other States to develop a coordinated emission 
management approach to its regional haze SIP and to address Ohio's 
impact on nearby Class I areas. Ohio EPA participated in the LADCO and 
inter-RPO processes, which developed the technical information needed 
for such coordinated strategies.
    Ohio participated in the LADCO Regional Haze Technical Workgroup 
meetings with other LADCO States, FLMs, and EPA Region 5. Through 
LADCO, Ohio also consulted with other States and Tribes.
    Ohio EPA received and responded to requests from MANE-VU and VISTAS 
on behalf of the States in their RPOs. On August 25, 2017, Ohio EPA 
received the ``Statement of the Mid-Atlantic/Northeast Visibility Union 
(MANE-VU) Class I Area States concerning a Course of Action in 
Contributing States Located Upwind of MANE-VU toward Assuring 
Reasonable Progress for the Second Regional Haze Implementation Period 
(2018-2028),'' (2017 MANE-VU Ask).\48\ MANE-VU is the RPO for the 
Northeastern and Mid-Atlantic States and Tribal Governments, which 
include: Connecticut, Delaware, the District of Columbia, Maine, 
Maryland, Massachusetts, New Hampshire, New Jersey, New York, 
Pennsylvania, Penobscot Indian Nation, Rhode Island, St. Regis Mohawk 
Tribe, and Vermont. For the second implementation period, MANE-VU 
performed contribution analyses to identify source and State-level 
contributions to visibility impairment and the need for interstate 
consultation. MANE-VU used the results of these analyses to determine 
emission units in various States that have a potential for visibility 
impacts of 3.0Mm-1 or greater using action 2015 emissions 
from EGUs and 2011 emissions from other sources. For Ohio, MANE-VU 
identified 8 units at the following facilities: Avon Lake Power Plant 
(Unit 12), General James M. Gavin Power Plant (Units 1 and 2), and 
Muskingum River (Units 1, 2, 3, 4, and 5). The five specific parts of 
the 2017 MANE-VU Ask requested Ohio and other upwind States to pursue 
specific emission management strategies to meet the 2028 reasonable 
progress goals for the second regional haze implementation period. On 
December 20, 2017, LADCO responded to the MANE-VU Ask, indicating that 
LADCO did not agree with MANE-VU's impact assessment results and 
recommended that MANE-VU use emissions estimates that, in the opinion 
of LADCO, better reflect the current state of knowledge.\49\ On 
December 29, 2017, Ohio EPA also responded to the 2017 MANE-VU Ask to 
address the requests and alleged inaccuracies regarding Ohio sources, 
which did not include recent permanent shutdowns or fuel conversions 
and resulted in modeling that overestimated Ohio's contribution.\50\
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    \48\ MANE-VU's ``2017 Statement of the Mid-Atlantic/Northeast 
Visibility Union (MANE-VU) Class I Area States concerning a Course 
of Action in Contributing States Located Upwind of MANE-VU toward 
Assuring Reasonable Progress for the Second Regional Haze 
Implementation Period (2018-2028)'' dated August 25, 2017, which 
includes a link to MANE-VU's contribution analyses report at http://www.otcair.org.manevu, is provided as appendix M1 to Ohio's Regional 
Haze SIP submission in the docket.
    \49\ LACDO's December 20, 2017, response to the MANE-VU Ask is 
found in appendix M2 of Ohio's Regional Haze SIP revision submittal 
in the docket.
    \50\ Ohio EPA's December 29, 2017, Technical Response Letter to 
the 2017 MANE-VU Ask is found in appendix M3 of Ohio's Regional Haze 
SIP revision in the docket.
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    MANE-VU Ask 1 requested that States ``ensure the most effective use 
of control technologies on a year-round basis to consistently minimize 
emissions of haze precursors, or obtain equivalent alternative emission 
reductions'' at EGUs ``with a nameplate capacity larger than or equal 
to 25 MW with already installed NOX and/or SO2 
controls.'' MANE-VU Ask 2 requested four-factor analyses be performed 
for any source modeled by MANE-VU that has the potential for a 
visibility impact greater than 3.0 Mm-1. In response to both 
MANE-VU Asks 1 and 2, Ohio EPA referred to its Q/d source selection 
process and four-factor analyses, where Ohio made a determination of 
existing effective controls or provided a four-factor analysis for the 
sources identified by MANE-VU: Avon Lake Power Plant and General James 
M. Power Plant, with the exception of Muskingum River Power Plant, 
which permanently shut down in 2015.
    MANE-VU Ask 3 requested States pursue, before 2028, an ultra-low 
sulfur fuel oil standard for #2 distillate oil of 0.0015 percent sulfur 
by weight or 15 ppm, for #4 residual oil of 0.25-0.5 percent sulfur by 
weight, and for #6 residual oil of 0.3-0.5 percent sulfur by weight. 
Ohio responded to MANE-VU Ask 3 by explaining that these fuel types do 
not comprise a significant portion of fuel usage in Ohio, and as such, 
would have little impact on visibility and would not warrant further 
evaluation and standard setting.
    MANE-VU Ask 4 requested States lock in lower emission rates for 
SO2, NOX, and PM at EGUs and sources with more 
than 250 MMBtu/hour heat input that have switched to lower emitting 
fuels by updating permits, enforceable agreements, and/or rules. Ohio 
responded to MANE-VU Ask 4 that, in most cases, switches to lower 
emitting fuels have already been incorporated into Ohio's federally 
enforceable permits, however, lowering emission rates for such 
facilities across the board is not required or appropriate.
    MANE-VU Ask 5 requested States include, in their Regional Haze SIP 
revision, measures to decrease energy demand by improved energy 
efficiency and to increase use of Combined Heat and Power and 
distributed generation technologies, such as fuel cells, wind,

[[Page 71144]]

and solar. Ohio responded to MANE-VU Ask 5, noting that Ohio EPA lacks 
the legislative authority to set energy policy, but encourages energy 
efficiency through efforts such as Ohio's Encouraging Environmental 
Excellence Program.\51\
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    \51\ Ohio's Encouraging Environmental Excellence Program is 
available at https://epa.ohio.gov/divisions-and-offices/environmental-financial-assistance/recognition-and-awards/e3-program.
---------------------------------------------------------------------------

    MANE-VU issued a second statement to Ohio EPA, similar to the one 
discussed above and also dated August 25, 2017, entitled, ``Statement 
of the Mid-Atlantic/Northeast Visibility Union (MANE-VU) Concerning a 
Course of Action Within MANE-VU Toward Assuring Reasonable Progress for 
the Second Implementation Period (2018-2028).'' \52\ Ohio EPA responded 
to MANE-VU's request, noting that even though Ohio's source selection 
process did not result in the selection of peaking combustion turbines 
for four-factor analysis, Ohio considered such NOX controls 
and did not find the measures necessary for Ohio sources during the 
second implementation period.
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    \52\ MANE-VU's second statement dated August 25, 2017, entitled 
``Statement of the Mid-Atlantic/Northeast Visibility Union (MANE-VU) 
Concerning a Course of Action Within MANE-VU Toward Assuring 
Reasonable Progress for the Second Implementation Period (2018-
2028)'' is included as appendix O in Ohio's Regional haze SIP 
revision included in the docket.
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    On June 22, 2020, the VISTAS RPO sent a letter to Ohio EPA on 
behalf of Alabama, Georgia, North Carolina, South Carolina, Tennessee, 
Virginia, and West Virginia.\53\ VISTAS shared with Ohio EPA the 
results of a technical analyses identifying Ohio sources to which 
VISTAS attributed significant impacts on visibility impairment at Class 
I areas within the VISTAS states. VISTAS' analyses identified sources 
with a sulfate or nitrate impact greater than 1.00 percent of the total 
sulfate plus nitrate point source visibility impairment on the 20 
percent most impaired days for each Class I area. For Ohio, VISTAS 
identified the following four sources: Ohio Valley Electric Corp.--
Kyger Creek Station, Cardinal Power, General James M. Gavin Power 
Plant, and Zimmer Power Station. VISTAS requested that Ohio conduct a 
reasonable progress analysis for each of the four sources, and, if Ohio 
determined that a four-factor analysis was not warranted, provide a 
rationale.
---------------------------------------------------------------------------

    \53\ VISTAS June 22, 2020, letter to Ohio EPA is included as 
appendix N1 in Ohio's Regional Haze SIP revision included in the 
docket.
---------------------------------------------------------------------------

    On October 29, 2020, Ohio EPA responded to VISTAS request by 
providing information for each of the four sources on emissions 
controls, control efficiencies, permitted limits, consent decree 
provisions, and trends in emission rates and annual emissions from 2016 
to 2019.\54\ Citing to examples in the 2019 Guidance of sources with 
effective emission controls, Ohio replied to VISTAS that, other than 
Zimmer Power Station, each of the other sources have existing effective 
controls with FGD or SCR with at least 90 percent effectiveness, and 
that a four-factor analysis would likely result in the conclusion that 
no further controls are necessary. For Zimmer Power Station, Ohio EPA 
confirmed that the facility announced it would permanently shut down in 
2027, and that discussions were underway to secure the upcoming 
shutdown in an enforceable commitment such that a four-factor analysis 
would not be warranted.
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    \54\ Ohio's October 29, 2020, response to VISTAS is included as 
appendix N2 to Ohio's Regional Haze SIP revision included in the 
docket.
---------------------------------------------------------------------------

    In addition to the measures identified by MANE-VU and VISTAS above, 
Ohio reviewed the Regional Haze SIPs for other States, that were 
available at the time, to ensure appropriate consideration was given to 
measures determined necessary by other States for similar types of 
sources as those selected by Ohio for four-factor analysis, which were 
EGUs and lime manufacturing plants.
    EPA proposes to find that Ohio has satisfied the consultation 
requirements of 40 CFR 51.308(f)(2)(ii). Ohio has met the 40 CFR 
51.308(f)(2)(ii)(A) and (B) requirements with its participation in the 
LADCO consultation process plus its individual consultation meetings 
with contributing States. There were no disagreements with another 
State, therefore 40 CFR 51.308(f)(2)(ii)(C) does not apply to Ohio.
    The requirements of 40 CFR 51.308(f)(2)(iii) provide that a State 
must document the technical basis for its decision making to determine 
the emission reductions measures that are necessary to make reasonable 
progress. The documentation requirement of 40 CFR 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.'' Ohio documented the technical basis, including the 
modeling, monitoring, engineering, costs, and emissions information 
that was relied on in determining the emission reduction measures that 
are necessary to make reasonable progress.
    For modeling, Ohio EPA documented the modeling done by LADCO to 
determine visibility projections and contributions to impairment at the 
Class I areas. Ohio included justification for the 2016 base year 
selection and the 2028 emission projections based on ERTAC forecasts 
and State-reported changes.
    For monitoring, Ohio described how ambient air quality monitoring 
data were analyzed to produce a conceptual understanding of the air 
quality problems contributing to haze as well as to project visibility 
conditions in 2028 through LADCO's modeling and EPA's Updated 2028 
Visibility Air Quality Modeling. Ohio noted that LADCO relied upon the 
IMPROVE monitoring data to track the chemical composition of 
PM2.5 in haze at Class I areas in the LADCO region, which 
included ammonium nitrate, ammonium sulfate, elemental carbon, organic 
carbon, sea salt, and inorganic soil. Ohio EPA also pointed to its 
statewide monitoring network of EPA-approved monitors for ozone and 
PM2.5, which Ohio continually reviews and uses to determine 
the contribution of emissions from sources within Ohio to visibility 
impairment at Class I areas in other States for SIP development.
    For emissions information, Ohio EPA provided data for 2016 through 
2019, the most recent data year available at the time, from various 
sources for each unit screened in using Ohio's Q/d source selection 
threshold. Data from 2016 for annual emissions of NOX, 
SO2, PM2.5, and NH3 that was used by 
LADCO in the Q/d analysis relied upon the 2016 inventory developed by 
the National Emissions Inventory Collaborative described above. 
Emissions data for 2016-2019 for NOX and SO2 were 
obtained from EPA's Clean Air Markets Database (CAMD) for sources that 
report emissions data to CAMD. To quantify emissions from sources that 
do not report to CAMD, data for 2017-2019 was obtained from Ohio EPA's 
EIS. Ohio also provided an emissions summary by source category and 
pollutant obtained from the 2017 NEI, the most recent triennial NEI 
available at the time. For engineering and costs, Ohio EPA provided 
site-specific four-factor analyses, which evaluated potential 
engineering designs and costs for various NOX and 
SO2 emission control systems for 4 coal-fired EGUs at 3 
different power plants (Avon Lake Power Plant, Dover Municipal Light & 
Power Plant, and General James M. Gavin Power Plant) and 2 coal-fired 
boilers at one lime manufacturing plant (Carmeuse Lime, Inc.--Maple 
Grove Operations). Additionally, Ohio EPA

[[Page 71145]]

provided information to support to the incorporation of specific 
emissions rates in the long-term strategy and the SIP at 40 CFR 
52.1870(d) at three power plants for the purposes of regional haze 
(Cardinal Power Plant, General James M. Gavin Power Plant, and Ohio 
Valley Electric Corp.--Kyger Creek Station). EPA proposes to find that 
such documentation of the technical basis of the long-term strategy 
satisfies the requirements of 40 CFR 51.308(f)(2)(iii).
    The provisions of 40 CFR 51.308(f)(2)(iii) require 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 EPA (or a more recent year), with a 12-month 
exemption period for newly submitted data. As previously mentioned 
above, Ohio EPA participated in the development of technical analyses, 
including emission inventory information, by LADCO and its member 
States, and is relying in part on those analyses to satisfy the 
emission inventory requirements. Ohio EPA explained that emissions for 
the 2016 base year and the 2028 projected year used in LADCO's modeling 
address elements of 40 CFR 51.308(f)(6)(v) of the Regional Haze Rule, 
which requires that States provide recent and future year emissions 
inventories of pollutants anticipated to contribute to visibility 
impairment in any Class I areas. Ohio EPA's regional haze SIP revision 
for the second implementation period also included 2017 NEI emission 
data, which corresponds to the year of the most recent triennial NEI at 
the time of Ohio's SIP submission, as required under 40 CFR 
51.308(f)(2)(iii) of the Regional Haze Rule. Based on Ohio EPA's 
consideration and analysis of the 2017 emission data in its SIP 
submittal, EPA proposes to find that Ohio has satisfied the emissions 
information requirement in 40 CFR 51.308(f)(2)(iii).
6. Five Additional Factors
    In addition to the four statutory factors, States must also 
consider the five additional factors listed in 40 CFR 51.308(f)(2)(iv) 
in developing their long-term strategies.
    As required by 40 CFR 51.308(f)(2)(iv)(A), Ohio EPA considered 
emission reductions due to ongoing air pollution control programs. Ohio 
EPA noted ongoing Federal and State emission control programs that have 
reduced and will continue to reduce visibility impairing pollutants 
from Ohio point and area sources as well as on-road and non-road mobile 
sources in the second implementation period. For point sources, this 
included Federal provisions for title V permitting actions; Acid Rain 
Program; Boiler MACT; VOC MACT; Combustion turbine MACT; NSPS for New 
Residential Wood Heaters; NSPS for Commercial and Industrial Solid 
Waste Incinerators; NESHAPs for Industrial, Commercial, and 
Institutional Area Source Boilers, Major Source Boilers; NESHAP for 
Reciprocating Internal Combustion Engines; Mercury and Air Toxics 
Standards for power plants; oil and natural gas industry standards; 
SO2 DRR; and Revised CSAPR Update. For area sources, 
regulations include national emission standards for aerosol coatings 
plus State regulations for Ohio's consumer product rules, Ohio's 
Architectural and Industrial Maintenance coatings rules, and Ohio's 
portable fuel container rules.
    For on-road mobile sources, Ohio EPA cited to Federal regulations 
for the Motor Vehicle Emission Control Program--low sulfur gasoline and 
ultra-low sulfur diesel fuel; Control of Hazardous Air Pollutants from 
Mobile Sources; and NOX Emission Standards for New 
Commercial Aircraft Engines. Among the controls for on-road mobile 
sources is the Ohio-administered Federal inspection and maintenance (I/
M) program known as ``E-check'' in northeast Ohio, codified at Ohio 
Administrative Code 3745-26-01(Z). For non-road mobile sources, Ohio 
EPA cited to Federal regulations for the Clean Air Non-road Diesel 
Rule, Non-road Spark-Ignition Engines and Recreational Engine 
Standards, New Non-road Spark Ignition Engines, heavy-duty diesel 
engine standard/low sulfur fuel, railroad/locomotive standards, and 
commercial marine vessel engine standards. For both on-road and non-
road mobile sources, Ohio EPA also provided information about Ohio's 
Beneficiary Mitigation Plan, which accepted and distributed funds from 
the Volkswagen settlement in 2018, resulting in benefits that compound 
over the lifetime of the equipment purchased or repowered. This 
included $40 million to on-road fleets (school bus replacements, 
transit bus replacements, and class 4-8 local freight and port drayage 
trucks and shuttle buses), $19 million to non-road equipment (tugboats, 
ferries, switcher locomotives, airport ground support, and port cargo 
handling equipment); and $11.25 million for infrastructure to support 
Zero Emissions Vehicles.
    As required by 40 CFR 51.308(f)(2)(iv)(B), Ohio's consideration of 
measures to mitigate the impacts of construction activities in its SIP 
submission focus on windblown dust resulting from earth moving 
activities as a primary source of airborne particles. For work on 
construction sites where greater than one acre of land is disturbed, 
Ohio EPA points to general permits required under the National 
Pollutant Discharge Elimination System, which require best management 
practices to control soil erosion and stormwater runoff that are also 
effective in preventing and reducing airborne soil as particulate 
matter emissions.
    Pursuant to 40 CFR 51.308(f)(2)(iv), Ohio EPA's SIP submission 
addressed schedules for source retirements, replacements, and natural 
gas conversions for 18 coal-fired units that are or will be permanent 
and federally enforceable during the second implementation period. As 
such, Ohio did not select these sources for a four-factor analysis. 
During the second implementation period, as enumerated above, 12 coal-
fired EGUs have already permanently shut down, 3 coal-fired units 
converted to natural gas, and 3 coal-fired EGUs will permanently shut 
down by 2028. These retirements and conversions contribute to Ohio's 
emission reductions and the associated visibility improvements at the 
affected Class I areas for the second implementation period.
    In considering smoke management for prescribed burns as required in 
40 CFR 51.308(f)(2)(iv)(D), Ohio EPA referred to interrelated laws and 
regulations for management of air emissions from prescribed fires. 
Among the enforcing agencies is the Ohio Department of Natural 
Resources Division of Forestry, which has the authority under Ohio 
Revised Code (ORC) 1503.18 \55\ to ban outdoor burning statewide in 
unincorporated areas during certain months and times of the year and to 
provide waivers only for individuals who are Certified Prescribed Fire 
Managers. In addition, OAC 3745-19 \56\ ``Open Burning Standards'' 
regulates prescribed fires for horticultural, silvicultural, range, or 
wildfire management practices and requires applications for permission, 
which must specify methods to reduce air emissions and certify 
adherence to the requirements of OAC 3745-19. To put Ohio's 
contribution from prescribed fires into context, Ohio EPA also provided 
emissions data from the 2017

[[Page 71146]]

NEI showing that prescribed fire activity in the State constitutes less 
than 1 percent of total U.S. prescribed fire emissions.
---------------------------------------------------------------------------

    \55\ Ohio Revised Code (ORC), title 15 Conservation of Natural 
Resources, Chapter 1503 Division of Forestry, Section 1503.18 is 
available at https://codes.ohio.gov/ohio-revised-code/section-1503.18.
    \56\ Ohio Administrative Code (OAC), Chapter 3745-19 Open 
Burning Standards is available at https://codes.ohio.gov/ohio-administrative-code/chapter-3745-19.
---------------------------------------------------------------------------

    As required by 40 CFR 51.308(f)(2)(iv), Ohio EPA considered the 
anticipated net effect on visibility improvements at the LADCO Class I 
Areas due to projected changes in emissions from point, area, and 
mobile sources during the second implementation period. For each 
potential control measure evaluated in the four-factor analyses, Ohio 
EPA projected the maximum estimated visibility benefit at any Class I 
area among the sources that were modeled, as listed in Table 18 of 
Ohio's SIP submission, to compare the relative control measures at a 
particular facility. Ohio considered cost-effectiveness along with time 
necessary to install controls, energy and non-air quality environmental 
impacts, and remaining useful life. Ohio found no potential new add-on 
controls necessary for reasonable progress.
    Ohio EPA considered other projected changes in emissions that would 
affect visibility at the LADCO Class I Areas. The visibility 
improvement expected during the second implementation period was 
estimated using LADCO's 2016 base year and 2028 future year inventory 
components to simulate 2016 and 2028 air quality. As described above, 
for EGUs, projected changes for 2028 emissions in LADCO's modeling 
platform were based on ERTAC forecasts and State-reported changes. For 
most other emission sectors, LADCO relied upon EPA's 2016 and 2028 
inventory estimates for projected changes. As Ohio EPA pointed out in 
section III.3(e)(5) of its SIP submission, these projected changes in 
EPA's 2016 and 2028 inventory estimates took into account Federal on-
the-books controls, such as those listed in Ohio's long-term strategy 
above. In addition, as noted in section III.3(e)(5) of Ohio's SIP 
submission, improvements in visibility are also anticipated by the end 
of the second implementation period due to the upcoming permanent 
shutdowns of coal-fired EGUs at Miami Fort Power Station and Zimmer 
Power Station by 2028.
    Ohio EPA also demonstrated that visibility conditions in the LADCO 
Class I Areas have shown continued improvement relative to baseline 
conditions. As depicted in LADCO's 2021 TSD, 2016 visibility impairment 
conditions at the LADCO Class I Areas on the 20 percent most impaired 
days as well as the 20 percent clearest days were below their 
respective glidepaths. By the end of the second implementation period 
in 2028, both LADCO's projections and EPA's Updated 2028 Visibility Air 
Quality Modeling show 2028 visibility conditions will be below the URP 
glidepaths for the LADCO Class I Areas.
    Ohio EPA concluded, in section V of its SIP submission, that when 
weighing the four-factor analyses and the five additional required 
factors, new add-on controls are not necessary to meet second 
implementation period regional haze SIP requirements beyond the 
measures included in Ohio's long-term strategy. Ohio's process for 
selecting sources for four-factor analyses represented 80 percent of 
the total SO2 and 57 percent of NOX for all 
sources with Q greater than 0.1 tons per year and provided an 
analytical means for refining the list based on shutdowns, conversions, 
and existing effective controls. For the add-on controls evaluated for 
the 6 units selected for four-factor analyses, Ohio considered the cost 
effectiveness, time necessary to install the controls, energy and solid 
waste impacts, the costs/sales ratio, and comparable visibility 
benefits in determining that the controls evaluated were not cost 
effective to achieve emission reductions during the second 
implementation period. Ohio EPA reflected upon the steady and 
significant improvement in visibility at each of the Class I areas 
impacted by sources in Ohio and noted that LADCO's modeling shows 
continued improvement with 2028 projections below their URP glidepaths. 
As discussed under the progress report elements below, from 2005 to 
2017, Ohio's SO2 emissions decreased by 90 percent while 
NOX emissions decreased by 47 percent. During the second 
implementation period, the decreasing trend continues with the 
shutdowns of 12 coal-fired EGUs at 4 facilities and the upcoming 
permanent shutdowns of 3 more coal-fired EGUs at 2 power stations. 
Given all these factors, Ohio concluded that the on-the-books and on-
the-way controls included in its long-term strategy, including the 
shutdowns and emission limits for NOX and SO2 in 
the DFFOs, are more than sufficient to make reasonable progress in the 
second implementation period. EPA proposes to find that Ohio reasonably 
considered and satisfied the requirements for each of the five 
additional factors in 40 CFR 51.308(f)(2)(iv) in developing its long-
term strategy.

F. Reasonable Progress Goals

    The provisions of 40 CFR 51.308(f)(3) contain the requirements 
pertaining to RPGs for each Class I area. Under 40 CFR 51.308(f)(3)(i), 
a State, in which a mandatory Class I area is located, is required 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. The provisions of 40 CFR 
51.308(f)(3)(ii) apply 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 40 CFR 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. The provisions of 40 CFR 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 
demonstration. Because Ohio has no Class I areas within its borders to 
which the requirements of the visibility protection program apply in 40 
CFR part 81, subpart D, Ohio is subject only to 40 CFR 
51.308(f)(3)(ii)(B), but not 40 CFR 51.308(f)(3)(i) or (f)(3)(ii)(A).
    Under 40 CFR 51.308(f)(3)(ii)(B), a State that contains sources 
that are reasonably anticipated to contribute to visibility impairment 
in a Class I area in another State for which a demonstration by the 
other State is required under 40 CFR 51.308(f)(3)(ii)(B) must 
demonstrate that there are no additional emission reduction measures 
that would be reasonable to include in its long-term strategy. Ohio's 
SIP submission at Table 1, section III(7)(b), and appendix A show that 
at each of the Class I areas impacted by emissions from Ohio, the 2028 
projected visibility impairment is not above the adjusted URP 
glidepaths for the 20 percent most impaired days

[[Page 71147]]

and ensures no degradation on the 20 percent clearest days. Therefore, 
EPA proposes it is reasonable to assume that the demonstration 
requirement under 40 CFR 51.308(f)(3)(ii)(B) as it pertains to these 
areas will not be triggered.
    EPA proposes to determine that Ohio has satisfied the applicable 
requirements of 40 CFR 51.308(f)(3) relating to RPGs.

G. Monitoring Strategy and Other Implementation Plan Requirements

    The requirements of 40 CFR 51.308(f)(6) specify 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 IMPROVE network.
    The provisions of 40 CFR 51.308(f)(6)(i) require 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. The provisions of 51.308(f)(6)(ii) require 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. As noted above, Ohio does not have 
any mandatory Class I Federal areas located within its borders to which 
the requirements of the visibility protection program apply in 40 CFR 
part 81, subpart D. Therefore, 40 CFR 51.308(f)(6)(i) and (ii) do not 
apply.
    The provisions of 40 CFR 51.308(f)(6)(iii) require States with no 
Class I areas to include 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 Class I 
areas in other States. States with Class I areas must establish a 
monitoring program and report data to EPA that is representative of 
visibility at the Class I Federal areas. The IMPROVE network meets this 
requirement. Ohio EPA stated that, as a participant in LADCO, it 
reviewed information about the chemical composition of baseline 
monitoring data at LADCO Class I Federal areas to understand the 
sources of haze causing pollutants. Ohio EPA does not operate any 
monitoring sites under the Federal IMPROVE program and, therefore, does 
not require approval of its monitoring network under the Regional Haze 
Rule. Ohio EPA relies upon participation in the IMPROVE network as part 
of the State's monitoring strategy for regional haze to review progress 
and trends in visibility at Class I areas that may be affected by 
emissions from Ohio, for comprehensive periodic revisions of this 
implementation plan, and for periodic reports describing progress 
towards the reasonable progress goals for those areas. Ohio also runs a 
monitoring network of EPA-approved monitors for ozone and 
PM2.5, as described in section III(8)(c) of Ohio's SIP 
submission, which Ohio EPA uses to determine the contribution of 
emissions from sources within Ohio to visibility impairment at Class I 
areas in other States for SIP development.
    The provisions of 40 CFR 51.308(f)(6)(iv) require the SIP to 
provide for the reporting of all visibility monitoring data to the 
Administrator at least annually for each Class I area in the State. As 
noted above, Ohio does not have any mandatory Class I Federal areas 
located within its borders to which the requirements of the visibility 
protection program apply in 40 CFR part 81, subpart D, and, therefore, 
40 CFR 51.308(f)(6)(iv) does not apply.
    The provisions of 40 CFR 51.308(f)(6)(v) require SIPs to provide 
for a statewide inventory of emissions of pollutants that are 
reasonably anticipated to cause or contribute to visibility impairment, 
including emissions for the most recent year for which data are 
available. Ohio EPA, as described in section III(8)(c)(ii) of its SIP 
submission, provided statewide emission inventories, including data 
from 2017 as the most recent year available at the time of the State's 
SIP submission, by complying with EPA's AERR. In 40 CFR part 51, 
subpart A, the AERR requires States to submit updated emissions 
inventories for criteria pollutants to EPA's Emissions Inventory System 
every three years. The emission inventory data is used to develop the 
NEI, which provides for, among other things, a triennial State-wide 
inventory of pollutants that are reasonably anticipated to cause or 
contribute to visibility impairment. Ohio's SIP submission, in section 
III(8)(b), includes a table of 2017 NEI data with source categories 
covering emissions from EGU point, non-EGU point, on-road, non-road, 
commercial marine vessels, dust, and other for the following 
pollutants: SO2, NOX, PM2.5, 
PM10, VOC, and NH3. To depict changes in 
emissions over time, Ohio EPA accompanied the 2017 NEI data with side-
by-side comparisons comparing 2005 emissions for the same source 
categories and pollutants. Ohio EPA also provided a summary of 
SO2, NOX, PM2.5, VOCs, and 
NH3 emissions for 2016 that LADCO used in developing Q/d 
metrics and the 2016 base year emissions inventory to project emissions 
to year 2028. Additionally, as described in further detail under the 
progress report elements in section III(8)(b) of Ohio's SIP submission, 
Ohio EPA provided more recent data through 2019 from CAMD to depict 
trends in EGU emissions, which demonstrated a 94 percent decrease in 
SO2 emissions and an 84 percent decrease in NOX 
emissions from 2005 to 2019.
    The provisions of 40 CFR 51.308(f)(6)(v) also require States to 
include estimates of future projected emissions and include a 
commitment to update the inventory periodically. For future projected 
emissions, Ohio relied on the LADCO modeling and analysis, which 
estimated 2028 projected emissions of SO2 and NOX 
for specific facilities in the LADCO States to provide an assessment of 
expected future year air quality based on 2016 emissions as well as 
ERTAC and State forecasts. In addition to Ohio's commitment to comply 
with the AERR to periodically update EPA's emission inventories for 
creating and analyzing the NEI, Ohio annually updates the State's own 
EIS for pollutants anticipated to cause or contribute to visibility 
impairment in Class I areas to support future regional haze progress 
reports and SIP revisions.
    EPA proposes to find that Ohio has met the requirements of 40 CFR 
51.308(f)(6) as described above, including through its continued 
participation in LADCO, its own statewide EIS, and its emissions 
reporting to EPA under AERR.

H. Requirements for Periodic Reports Describing Progress Towards the 
Reasonable Progress Goals

    The provisions of 40 CFR 51.308(f)(5) require that periodic 
comprehensive revisions of States' regional haze plans also address the 
progress report requirements of 40 CFR 51.308(g)(1) through (5). The 
purpose of these requirements is to evaluate progress towards the 
applicable RPGs for each Class I area within the State and each Class I 
area outside the State that may be affected by emissions from within 
that State. The provisions of 40 CFR 51.308(g)(1) and (2) apply to all 
States

[[Page 71148]]

and require a description of the status of implementation of all 
measures included in a State's first implementation period regional 
haze plan and a summary of the emission reductions achieved through 
implementation of those measures. The provisions of 40 CFR 51.308(g)(3) 
apply only to States with Class I areas within their borders and 
requires such States to assess current visibility conditions, changes 
in visibility relative to baseline (2000-2004) visibility conditions, 
and changes in visibility conditions relative to the period addressed 
in the first implementation period progress report. The provisions of 
51.308(g)(4) apply to all States and requires an analysis tracking 
changes in emissions of pollutants contributing to visibility 
impairment from all sources and sectors since the period addressed by 
the first implementation period progress report. This provision further 
specifies the year or years through which the analysis must extend 
depending on the type of source and the platform through which its 
emission information is reported. Finally, 40 CFR 51.308(g)(5), which 
also applies to all States, requires an assessment of any significant 
changes in anthropogenic emissions within or outside the State have 
occurred since the period addressed by the first implementation period 
progress report, including whether such changes were anticipated and 
whether they have limited or impeded expected progress towards reducing 
emissions and improving visibility.
    Ohio's previous progress report, which was a 5-year progress report 
submitted as a SIP revision for the first implementation period on 
March 11, 2016, included emission inventories from 2002-2014 of 
NOX and SO2 for EGUs as well as inventories from 
2005 and 2011 of NOX, SO2, PM2.5, 
PM10, VOC, and NH3 for additional source 
categories: EGUs, non-EGUs, on-road, non-road, commercial marine 
vessels, and other. Based on CAMD data for emissions from EGUs covering 
the period 2002 to 2014, Ohio's 2016 5-year progress report showed a 
decrease in NOX emissions by 76 percent and a decrease in 
SO2 emissions by 75 percent. (82 FR 60543, December 21, 
2017).
    For the second implementation period SIP submittal, the 2019 
Guidance recommends the progress report cover the first full year that 
was not incorporated into the previous progress report through a year 
that is as close as possible to the submission date of the SIP. 2019 
Guidance at 55. Ohio's 2021 progress report, contained in section 
III(8)(b) of its SIP submission, covered the measures and emissions 
reductions achieved from 2005 through 2019, including 2017 as the most 
recent NEI year available at the time for sector level emissions.
    To address the progress report elements of 51.308(g)(1), Ohio EPA 
described the status of implementation of all measures in the long-term 
strategy under its first implementation period regional haze plan. 
These measures included several Federal measures, including CAIR and 
its successor CSAPR, to which Ohio attributed the majority of 
reductions in visibility-impairing emissions from the largest point-
source sector, EGUs, during the first implementation period, along with 
the Acid Rain Program under title IV and the NOX SIP Call. 
Additional on-the-books control measures that generated further 
emission reductions addressed mobile sources, such as on-road 
provisions under the Federal Motor Vehicle Emission Control Program for 
low-sulfur gasoline and ultra-low sulfur diesel fuel as well as the 
Ohio-administered Federal I/M program, E-check. Non-road Federal 
measures for mobile sources included the Clean Air Non-road Diesel 
Rule, the evaporative Large Spark Ignition and Recreational Vehicle 
standards, heavy-duty diesel engine standard for low-sulfur diesel 
fuel, railroad/locomotive standards, and commercial marine vessel 
engine standards. Measures for area sources included Ohio's consumer 
products rules for consumer solvents, Ohio's Architectural and 
Industrial Maintenance coatings rules, Ohio's portable fuel container 
rules, and NESHAP for aerosol coatings. Among the other measures, Ohio 
also included BART and Industrial Boiler MACT, which applied to only 
one EGU in the State.
    As required by 40 CFR 51.308(g)(2), Ohio provided a summary of the 
emission reductions achieved through the measures outlined above from 
the first implementation period. As a result of these measures, NEI 
data from 2005 to 2017 from across all emission categories, discussed 
more fully below, show that Ohio's SO2 emissions decreased 
by 90 percent, NOX emissions decreased by 57 percent, VOC 
emissions decreased by 33 percent, and ammonia emissions decreased by 
26 percent. The most significant emissions reductions from Ohio's SIP 
strategies were realized mainly as a result of CAIR and CSAPR, where 
CAMD data show that the EGU sector experienced a 94 percent decrease in 
SO2 from 1,085,485 tpy in 2005 to 68,905 tpy in 2019 as well 
as an 84 percent decrease in NOX from 255,000 tpy in 2005 to 
40,493 tpy in 2019. EPA proposes to find that Ohio has met the 
requirements of 40 CFR 51.308(g)(1) and (2) because its SIP submission 
describes the measures included in the long-term strategy from the 
first implementation period, as well as the status of their 
implementation and the emission reductions achieved through such 
implementation.
    The provisions of 40 CFR 51.308(g)(3) require States to assess 
Reasonable Progress Goals, including current visibility conditions and 
changes, for any Class I areas within the State. As described above, 
Ohio has no mandatory Class I Federal areas within its borders that are 
among the 156 mandatory Class I Federal areas where EPA deemed 
visibility to be an important value. Therefore, 40 CFR 51.308(g)(3) 
does not apply.
    To address 40 CFR 51.308(g)(4), Ohio EPA provided an analysis, in 
section III.8(b)(iv) of its SIP submittal, tracking the change in 
emissions of NOX, SO2, PM2.5, 
PM10, NH3, and VOC from all sources and 
activities in the State. Table 21 of Ohio's SIP submission documents 
changes in emissions of each of these pollutants for the EGU point, 
non-EGU point, on-road, non-road, commercial marine vessels, and other 
categories based on the NEIs from 2005 through 2017, the most recent 
NEI year available at the time for category level emissions. As a 
caveat, Ohio noted that there were several changes in the methodologies 
for estimating emissions between the 2005 and 2017 NEIs, such that they 
are not readily comparable as explained in EPA's 2017 National 
Emissions Inventory: January 2021 Updated Release, Technical Support 
Document.\57\ Specifically, these inconsistencies resulted from changes 
in the reporting of the condensable portion of PM emissions, changes in 
the model used for on-road and non-road emissions, as well as 
improvements in methodologies for other sources such as paved and 
unpaved PM emissions, ammonia fertilizer and animal waste emissions, 
oil and gas production, residential wood combustion, solvents, 
industrial and commercial/institutional fuel combustion, and commercial 
marine vessel emissions. While Ohio EPA noted that the inventories are 
not directly comparable, 40 CFR 51.308(g)(4) does not require States to 
revise previous NEI year estimates to use the same methods as a more 
recent year.
---------------------------------------------------------------------------

    \57\ 2017 National Emissions Inventory: January 2017 Updated 
Release, Technical Support Document,'' EPA-454/R-21=001, February 
2021. https://www.epa.gov/sites/default/files/2021-02/documents/nei2017_tsd_full_jan2021.pdf.

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[[Page 71149]]

    Ohio EPA's analysis of Table 21 documents overall emission 
reductions in NOX and SO2 across all source 
categories from the 2005 and 2017 NEIs, with a 90 percent reduction in 
SO2 and 57 percent reduction in NOX. Based on the 
2005 and 2017 NEIs, Ohio documented decreases in NOX 
emissions of 77 percent from EGU Point, 32 percent from non-EGU point, 
49 percent from on-road, 55 percent from non-road, 38 percent from 
commercial marine vessels, and 44 percent from other categories. For 
SO2, Ohio calculated decreases from the 2005 to 2017 NEIs of 
92 percent from EGU point, 77 percent from non-EGU point, 87 percent 
from on-road, 99 percent from non-road, 92 percent from commercial 
marine vessels, and 36 percent from other categories. Overall 
reductions in VOC and NH3 emissions, which Ohio EPA notes 
are less impactful on visibility in the LADCO Class I Areas, reached 33 
percent and 26 percent, respectively, despite an apparent increase in 
EGU point source emissions in NH3, which Ohio EPA attributes 
to changes in estimation methodologies at a few select facilities that 
Ohio EPA is investigating further. Similarly, while overall 
PM2.5 and PM10 emissions appear to increase by 14 
percent and 12 percent, respectively, Ohio EPA notes that a direct 
comparison between the 2005 and 2017 NEIs would be inaccurate because 
of the inconsistencies in PM reporting and changes in the modeling of 
emissions as explained above. In addition to the NEIs, Ohio EPA 
provided data, as noted earlier, with respect to EGUs that report to 
CAMD from 2005 to 2019, the most recent year available at the time, 
tracking the change in emissions and chronicling the decrease in 
SO2 by 94 percent and the decrease in NOX by 84 
percent. EPA proposes to find that Ohio has satisfied the requirements 
of 40 CFR 51.308(g)(4) by tracking the change in emissions of 
NOX, SO2, PM2.5, VOCs, and 
NH3 identified by type of source since the first progress 
report.
    To address 40 CFR 51.308(g)(5), Ohio EPA assessed significant 
changes in anthropogenic emissions since the first implementation 
period plan, within and outside of the State, including whether they 
were anticipated and whether they limited or impeded progress in 
improving visibility. Within the State, Ohio compared the 2005 and 2017 
NEIs in Table 21 of its submittal to identify changes in anthropogenic 
emissions, finding that emissions significantly decreased across all 
categories for NOX and SO2. As previously 
mentioned, these changes were anticipated and occurred mainly as a 
result of CSAPR as it replaced CAIR. Where emissions appeared to 
increase significantly, such as for NH3 emissions from EGU-
point source category, Ohio explained the changes occurred as a result 
the inconsistencies in the reporting, modeling, and methodologies used 
for the 2005 and 2017 NEI data sets as described above, and that Ohio 
is investigating the potential for the increases to be attributed to 
errors at a few select facilities. With the significant decreases in 
anthropogenic emissions of NOX, SO2, VOC, and 
NH3 across all source categories from 2005 to 2017 NEIs, 
Ohio EPA found that no changes in anthropogenic emissions within or 
outside Ohio have occurred from 2005 to 2017 that would limit or impede 
progress in reducing pollutant emissions and improving visibility. Ohio 
noted that further improvements in visibility are anticipated with the 
emission reductions to be realized the Revised CSAPR Update along with 
the permanent shutdown of coal-fired boilers at Miami Fort Power 
Station and Zimmer Power Station. The emissions trend data in Ohio's 
SIP submission support an assessment that anthropogenic haze-causing 
pollutant emissions in Ohio have decreased during the reporting period 
and that changes in emissions have not limited or impeded progress in 
reducing pollutant emissions and improving visibility. EPA proposes to 
find that Ohio has met the requirements of 40 CFR 51.308(g)(5).
    Following up on Ohio's 2021 progress report, in section III.8(b)of 
its SIP submission, Ohio EPA committed to submit a progress report for 
the second implementation period by January 31, 2025, to evaluate 
progress towards the reasonable progress goal for each mandatory Class 
I Federal area located within and outside the State that may be 
affected by emissions from within the State as required by 40 CFR 
51.308(g).

I. Requirements for State and Federal Land Manager Coordination

    CAA section 169A(d) requires States to consult with FLMs before 
holding the public hearing on a proposed regional haze SIP and to 
include a summary of the FLMs' conclusions and recommendations in the 
notice to the public. In addition, 40 CFR 51.308(i)(2)'s FLM 
consultation provision requires a State to provide FLMs with an 
opportunity for consultation that is early enough in the State's policy 
analyses of its emission reduction obligation so that information and 
recommendations provided by the FLMs' can meaningfully inform the 
State's decisions on its long-term strategy. If the consultation has 
taken place at least 120 days before a public hearing or public comment 
period, the opportunity for consultation will be deemed early enough. 
Regardless, the opportunity for consultation must be provided at least 
60 days before a public hearing or public comment period at the State 
level. The requirements of 40 CFR 51.308(i)(2) also provide two 
substantive topics on which FLMs must be provided an opportunity to 
discuss with States: assessment of visibility impairment in any Class I 
area and recommendations on the development and implementation of 
strategies to address visibility impairment. In 40 CFR 51.308(i)(3), 
States, in developing their implementation plans, are required to 
include a description of how they addressed FLMs' comments.
    In development of its SIP submittal, Ohio participated with the 
FLMs in an early engagement process as well as a formal consultation 
process, sharing drafts of its SIP submission, reviewing information 
provided by the FLMs, and meeting to discuss the development of Ohio's 
proposed Regional Haze plan. On May 12, 2020, and October 2, 2020, Ohio 
received lists of sources recommended for four-factor analyses by NPS 
and USFS, respectively, which are included as Appendices K2 and K3 in 
Ohio's SIP submission. On October 8, 2020, Ohio EPA shared an early 
draft of its Regional Haze plan with USFS, FWS, and NPS for their 
review and comments. Following this early engagement process, Ohio 
initiated a formal consultation process with the FLMs on January 6, 
2021, providing another draft of its Regional Haze plan and offering an 
opportunity for consultation in person. Ohio EPA initiated the early 
engagement process more than 120 days before the first public comment 
period on Ohio's plan and began the formal consultation process at 
least 60 days prior to the first public comment period on Ohio's plan 
as required by 40 CFR 51.308(i)(2). On February 10, 2021, USFS shared 
their comments on the draft plan with Ohio EPA, and NPS shared their 
comments with Ohio EPA on February 17, 2021, both of which are 
contained in Appendices L1, L2, L3 of Ohio's SIP submission. Ohio EPA's 
response to the FLM's comments from February 2021 are included as 
Appendix L4 of Ohio's SIP submittal as required by 40 CFR 51.308(i)(3).

[[Page 71150]]

    On May 10, 2021, Ohio announced its initial public comment period 
and public hearing regarding the State's proposed SIP submittal for the 
second implementation period on Ohio EPA's Regional Haze website,\58\ 
in the Ohio EPA Weekly Review,\59\ and through electronic mailing lists 
to interested parties, including FLMs. The public notice included FLM's 
comments and Ohio EPA's response in the proposed SIP submission. The 
initial public comment period took place from May 10, 2021, through 
June 28, 2021, being extended beyond the original 30-day period by an 
additional two weeks, and a virtual and in-person public hearing was 
held on June 14, 2021. Following the public comment period, Ohio 
submitted its SIP revision to EPA on July 30, 2021.
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    \58\ The Ohio EPA Regional Haze website is available at https://epa.ohio.gov/divisions-and-offices/air-pollution-control/state-implementation-plans/state-implementation-plan-sip-regional-haze.
    \59\ The Ohio EPA Weekly Review is available at https://epa.ohio.gov/about/media-center/public-notices.
---------------------------------------------------------------------------

    Subsequently, in 2023 and 2024, Ohio EPA re-engaged with the FLMs 
on a proposed supplement to its July 30, 2021, SIP submission. As 
discussed above, Ohio EPA shared a proposed supplement with the FLMs 
that included an analyses and proposed emission limits for General 
James M. Gavin Power Plant, Cardinal Power Plant, and Ohio Valley 
Electric Corp.--Kyger Creek Station. For the proposed supplement, Ohio 
EPA provided a 45-day FLM consultation period from January 16, 2024, to 
March 1, 2024, that ran concurrently with an extended public comment 
period from January 16, 2024, to March 18, 2024, during which Ohio made 
the FLM comments available to the public on its website by March 5, 
2024. A virtual and in-person public hearing on Ohio EPA's proposed 
supplement was held on March 18, 2024.
    Following the second public comment period, Ohio EPA again re-
engaged with the FLMs on proposed DFFOs that would effectuate the 
emissions limitations contained within the proposed supplement. After 
Ohio EPA and the FLMs agreed on a shortened FLM consultation period 
from May 3, 2024, to May 31, 2024, Ohio provided a third public comment 
period regarding draft DFFOs effectuating the proposed emission 
limitations from June 3, 2024, through July 8, 2024, and a virtual and 
in-person public hearing was held on July 8, 2024. Ohio EPA considered 
input from FLMs and the public provided during each of the three FLM 
consultation periods and three public notice periods when finalizing 
this SIP revision.
    As required by 40 CFR 51.308(i)(4), Ohio committed to continue 
consultation with States and FLMs on the development and review of any 
future plan revisions and progress reports, as well as other programs 
having the potential to contribute to visibility impairment in the 
mandatory Class I areas, including NSR sources that might impact 
visibility in Class I areas. Given Ohio EPA's actions recounted above, 
EPA proposes to find that Ohio has satisfied the requirements of 40 CFR 
51.308(i) to consult with the FLMs on its regional haze SIP for the 
second implementation period.

V. Proposed Action

    EPA proposes to approve Ohio's July 30, 2021, SIP submission, as 
supplemented on August 6, 2024, as satisfying the regional haze 
requirements for the second implementation period contained in 40 CFR 
51.308(f).

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the CAA and applicable 
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve State choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
action merely proposes to approve State law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by State law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 14094 (88 FR 21879, April 11, 
2023);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because it approves a State program;
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001); and
     Is not subject to requirements of Section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA.
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where EPA or an Indian Tribe has 
demonstrated that a Tribe has jurisdiction. In those areas of Indian 
country, the rule does not have Tribal implications and will not impose 
substantial direct costs on Tribal governments or preempt Tribal law as 
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).
    Executive Order 12898 (Federal Actions to Address Environmental 
Justice in Minority Populations and Low-Income Populations, 59 FR 7629, 
February 16, 1994) directs Federal agencies to identify and address 
``disproportionately high and adverse human health or environmental 
effects'' of their actions on communities with environmental justice 
(EJ) concerns to the greatest extent practicable and permitted by law. 
EPA defines EJ as ``the fair treatment and meaningful involvement of 
all people regardless of race, color, national origin, or income with 
respect to the development, implementation, and enforcement of 
environmental laws, regulations, and policies.'' EPA further defines 
the term fair treatment to mean that ``no group of people should bear a 
disproportionate burden of environmental harms and risks, including 
those resulting from the negative environmental consequences of 
industrial, governmental, and commercial operations or programs and 
policies.''
    Ohio EPA did not evaluate EJ considerations as part of its SIP 
submittal; the CAA and applicable implementing regulations neither 
prohibit nor require such an evaluation. EPA did not perform an EJ 
analysis and did not consider EJ in this action. Due to the nature of 
the action being taken here, this action is expected to have a neutral 
to positive impact on the air quality of the affected area. 
Consideration of EJ is not required as part of this action, and there 
is no information in the record inconsistent with the stated goal of 
E.O. 12898 of achieving environmental justice for communities with EJ 
concerns.

[[Page 71151]]

List of Subjects in 40 CFR Part 52

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

    Dated: August 21, 2024.
Debra Shore,
Regional Administrator, Region 5.
[FR Doc. 2024-19189 Filed 8-29-24; 8:45 am]
BILLING CODE 6560-50-P