
[Federal Register Volume 88, Number 164 (Friday, August 25, 2023)]
[Proposed Rules]
[Pages 58178-58202]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2023-18278]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R03-OAR-2022-0912; FRL-11269-01-R3]


Approval and Promulgation of Air Quality Implementation Plans; 
Maryland; Regional Haze State Implementation 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 regional haze state implementation plan (SIP) revision 
submitted by the State of Maryland on February 8, 2022, as satisfying 
applicable requirements under the Clean Air Act (CAA) and EPA's 
Regional Haze Rule for the program's second implementation period. 
Maryland'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. The SIP 
submission also addresses other applicable requirements for the second 
implementation period of the regional haze program. The EPA is taking 
this action pursuant to sections 110 and 169A of the Clean Air Act.

DATES: Written comments must be received on or before September 25, 
2023.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R03-
OAR-2022-0912 at www.regulations.gov. For comments submitted at 
Regulations.gov, follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from 
Regulations.gov. For either manner of submission, the EPA may publish 
any comment received to its public docket. Do not submit electronically 
any information you consider to be confidential business information 
(CBI) or other information whose disclosure is restricted by statute. 
Multimedia submissions (audio, video, etc.) must be accompanied by a 
written comment. The written comment is considered the official comment 
and should include discussion of all points you wish to make. The EPA 
will generally not consider comments or comment contents located 
outside of the primary submission (i.e., on the web, cloud, or other 
file sharing system). For additional submission methods, 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 www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Adam Yarina, U.S. Environmental 
Protection Agency, Region 3, 1600 John F. Kennedy Boulevard, 
Philadelphia, Pennsylvania 19103-2852, at (215) 814-2108, or by email 
at [email protected].

Table of Contents

I. What action is the 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 Maryland's Regional Haze Submission for the 
Second Implementation Period
    A. Background on Maryland's First Implementation Period SIP 
Submission
    B. Maryland's Second Implementation Period SIP Submission and 
the EPA's Evaluation
    C. Identification of Class I Areas
    D. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress
    E. Long-Term Strategy for Regional Haze
    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 the EPA proposing?

    On February 8, 2022, the Maryland Department of the Environment 
(MDE) submitted a revision to its SIP to address regional haze for the 
second implementation period. MDE made this SIP submission to satisfy 
the requirements of the CAA's regional haze

[[Page 58179]]

program pursuant to CAA sections 169A and 169B and 40 CFR 51.308. The 
EPA is proposing to find that the Maryland regional haze SIP submission 
for the second implementation period meets the applicable statutory and 
regulatory requirements and thus proposes to approve Maryland'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 the EPA to 
promulgate regulations to assure reasonable progress toward meeting 
this national goal. CAA 169A(a)(4). On December 2, 1980, the EPA 
promulgated regulations to address visibility impairment in mandatory 
Class I Federal areas (hereinafter referred to as ``Class I areas'') 
that is ``reasonably attributable'' to a single source or small group 
of sources. (45 FR 80084, December 2, 1980). These regulations, 
codified at 40 CFR 51.300 through 51.307, represented the first phase 
of the EPA's efforts to address visibility impairment. In 1990, 
Congress added section 169B to the CAA to further address visibility 
impairment, specifically, impairment from regional haze. CAA 169B. The 
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 the 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, the EPA also promulgated regulations 
specific to addressing regional haze visibility impairment in Class 
I areas on the Colorado Plateau at 40 CFR 51.309. The latter 
regulations are applicable only for specific jurisdictions' regional 
haze plans submitted no later than December 17, 2007, and thus are 
not relevant here.
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    Regional haze is visibility impairment that is produced by a 
multitude of anthropogenic sources and activities which are located 
across a broad geographic area and that emit pollutants that impair 
visibility. Visibility impairing pollutants include fine and coarse 
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). 
The EPA's Guidance on Regional Haze State Implementation Plans for 
the Second Implementation Period (``2019 Guidance'') offers the 
flexibility for the use of light extinction in certain cases. Light 
extinction can be simpler to use in calculations than deciviews, 
since it is not a logarithmic function. See, e.g., 2019 Guidance at 
16, 19, https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period, The EPA Office of 
Air Quality Planning and Standards, Research Triangle Park (August 
20, 2019). The formula for the deciview is 10 ln (b\ext\)/10 Mm-1). 
40 CFR 51.301.
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    To address regional haze visibility impairment, the 1999 RHR 
established an iterative planning process that requires both states in 
which Class I areas are located and states ``the emissions from which 
may reasonably be anticipated to cause or contribute to any impairment 
of visibility'' in a Class I area to periodically submit SIP revisions 
to address such impairment. CAA 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 35714 at 35768, July 
1, 1999). The EPA established in the 1999 RHR that all states either 
have Class I areas within their borders or ``contain sources whose 
emissions are reasonably anticipated to contribute to regional haze in 
a Class I area''; therefore, all states must submit regional haze 
SIPs.\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), (f).
    \5\ In addition to each of the fifty states, the EPA also 
concluded that the Virgin Islands and District of Columbia must also 
submit regional haze SIPs because they either contain a Class I area 
or contain sources whose emissions are reasonably anticipated to 
contribute regional haze in a Class I area. See 40 CFR 51.300(b) 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 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

[[Page 58180]]

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) and (d)(2). The 1999 RHR also provided that States' 
long-term strategies must include the ``enforceable emissions 
limitations, compliance, schedules, and other measures as necessary to 
achieve the reasonable progress goals.'' 40 CFR 51.308(d)(3). In 
establishing their long-term strategies, states are required to consult 
with other states that also contribute to visibility impairment in a 
given Class I area and include all measures necessary to obtain their 
shares of the emission reductions needed to meet the RPGs. 40 CFR 
51.308(d)(3)(i) and (ii). Section 51.308(d) also contains seven 
additional factors states must consider in formulating their long-term 
strategies, 40 CFR 51.308(d)(3)(v), as well as provisions governing 
monitoring and other implementation plan requirements. 40 CFR 
51.308(d)(4). Finally, the 1999 RHR required states to submit periodic 
progress reports--SIP revisions due every five years that contain 
information on states' implementation of their regional haze plans and 
an assessment of whether anything additional is needed to make 
reasonable progress, see 40 CFR 51.308(g) and (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 35714 at 35731-32, July 1, 1999. That is, the 
URP and the 2064 date are not enforceable targets, but are rather 
tools that ``allow for analytical comparisons between the rate of 
progress that would be achieved by the state's chosen set of control 
measures and the URP.'' (82 FR 3078, 3084, January 10, 2017).
    \7\ The EPA's regulations define ``Federal Land Manager'' as 
``the Secretary of the department with authority over the Federal 
Class I area (or the Secretary's designee) or, with respect to 
Roosevelt-Campobello International Park, the Chairman of the 
Roosevelt-Campobello International Park Commission.'' 40 CFR 51.301.
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    On January 10, 2017, the EPA promulgated revisions to the RHR, (82 
FR 3078, January 10, 2017), that apply for the second and subsequent 
implementation periods. The 2017 rulemaking made several changes to the 
requirements for regional haze SIPs to clarify States' obligations and 
streamline certain regional haze requirements. The revisions to the 
regional haze program for the second and subsequent implementation 
periods focused on the requirement that States' SIPs contain long-term 
strategies for making reasonable progress towards the national 
visibility goal. The reasonable progress requirements as revised in the 
2017 rulemaking (referred to here as the 2017 RHR Revisions) are 
codified at 40 CFR 51.308(f). Among other changes, the 2017 RHR 
Revisions adjusted the deadline for States to submit their second 
implementation period SIPs from July 31, 2018, to July 31, 2021, 
clarified the order of analysis and the relationship between RPGs and 
the long-term strategy, and focused on making visibility improvements 
on the days with the most anthropogenic visibility impairment, as 
opposed to the days with the most visibility impairment overall. The 
EPA also revised requirements of the visibility protection program 
related to periodic progress reports and FLM consultation. The specific 
requirements applicable to second implementation period regional haze 
SIP submissions are addressed in detail below.
    The EPA provided guidance to the states for their second 
implementation period SIP submissions in the preamble to the 2017 RHR 
Revisions as well as in subsequent, stand-alone guidance documents. In 
August 2019, the EPA issued ``Guidance on Regional Haze State 
Implementation Plans for the Second Implementation Period'' (``2019 
Guidance'').\8\ On July 8, 2021, the EPA issued a memorandum containing 
``Clarifications Regarding Regional Haze State Implementation Plans for 
the Second Implementation Period'' (``2021 Clarifications Memo'').\9\ 
Additionally, the EPA further clarified the recommended procedures for 
processing ambient visibility data and optionally adjusting the URP to 
account for international anthropogenic and prescribed fire impacts in 
two technical guidance documents: the December 2018 ``Technical 
Guidance on Tracking Visibility Progress for the Second Implementation 
Period of the Regional Haze Program'' (``2018 Visibility Tracking 
Guidance''),\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. www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period. The 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. www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf. 
The 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. 
www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional. The 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. www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program. The EPA Office of 
Air Quality Planning and Standards, Research Triangle Park (June 3, 
2020).
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    As previously 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 and 
Prevention of Significant Deterioration programs, as

[[Page 58181]]

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. In order to address regional haze, states 
need to develop strategies in coordination with one another, 
considering the effect of emissions from one jurisdiction on the air 
quality in another. Five regional planning organizations (RPOs),\13\ 
which include representation from state and tribal governments, the 
EPA, and FLMs, were developed in the lead-up to the first 
implementation period to address regional haze. RPOs evaluate technical 
information to better understand how emissions from State and Tribal 
land impact Class I areas across the country, pursue the development of 
regional strategies to reduce emissions of 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 
document, the terms RPO and MJO are synonymous.
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    The Mid-Atlantic/Northeast Visibility Union (MANE-VU), one of the 
five RPOs described above, is a 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 Mid-Atlantic and Northeast corridor of the United States. Member 
states and tribal governments (listed alphabetically) 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. The Federal partner members of MANE-VU are 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 are required to submit regional 
haze SIPs satisfying the applicable requirements for the second 
implementation period of the regional haze program by July 31, 2021. 
Each state's SIP must contain a long-term strategy for making 
reasonable progress toward meeting the national goal of remedying any 
existing and preventing any future anthropogenic visibility impairment 
in Class I areas. CAA 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 40 CFR 51.308(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) and (f)(2). For each Class I area within its borders, a state 
must then calculate the baseline, current, and natural visibility 
conditions for that area, as well as the visibility improvement made to 
date and the URP. See 40 CFR 51.308(f)(1). Each state having a Class I 
area and/or emissions that may affect visibility in a Class I area must 
then develop a long-term strategy that includes the enforceable 
emission limitations, compliance schedules, and other measures that are 
necessary to make reasonable progress in such areas. A reasonable 
progress determination is based on applying the four factors in CAA 
section 169A(g)(1) to sources of visibility-impairing pollutants that 
the state has selected to assess for controls for the second 
implementation period. Additionally, as further explained below, the 
RHR at 40 CFR 51.3108(f)(2)(iv) separately provides five ``additional 
factors'' \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 submissions 
revisions due by July 31, 2021, 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 the EPA according to the requirements applicable to all 
SIP revisions under the CAA and EPA's regulations. See CAA 169(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 the EPA finds that a state's SIP is 
incomplete or if disapproves the SIP, the Agency must promulgate a 
federal implementation plan (FIP) that satisfies the applicable 
requirements. CAA 110(c)(1).

A. Identification of Class I Areas

    The first step in developing a regional haze SIP is for a state to 
determine which Class I areas, in addition to those within its borders, 
``may be affected'' by emissions from within the state. In the 1999 
RHR, the EPA determined that all

[[Page 58182]]

states contribute to visibility impairment in at least one Class I 
area, 64 FR 35720-22, July 1, 1999, and explained that the statute and 
regulations lay out an ``extremely low triggering threshold'' for 
determining ``whether States should be required to engage in air 
quality planning and analysis as a prerequisite to determining the need 
for control of emissions from sources within their State.'' Id. at 
35721.
    A state must determine which Class I areas must be addressed by its 
SIP by evaluating the total emissions of visibility impairing 
pollutants from all sources within the state. While the RHR does not 
require this evaluation to be conducted in any particular manner, EPA's 
2019 Guidance provides recommendations for how such an assessment might 
be accomplished, including by, where appropriate, using the 
determinations previously made for the first implementation period. 
2019 Guidance at 8-9. In addition, the determination of which Class I 
areas may be affected by a state's emissions is subject to the 
requirement in 40 CFR 51.308(f)(2)(iii) to ``document the technical 
basis, including modeling, monitoring, cost, engineering, and emissions 
information, on which the State is relying to determine the emission 
reduction measures that are necessary to make reasonable progress in 
each mandatory Class I Federal area it affects.''

B. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress

    As part of assessing whether a SIP submission for the second 
implementation period is providing for reasonable progress towards the 
national visibility goal, the RHR contains requirements in 40 CFR 
51.308(f)(1) related to tracking visibility improvement over time. The 
requirements of this subsection apply only to states having Class I 
areas within their borders; the required calculations must be made for 
each such Class I area. EPA's 2018 Visibility Tracking Guidance \16\ 
provides recommendations 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://www3.epa.gov/ttnamti1/files/ambient/visible/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% clearest (the 20% 
of monitored days in a calendar year with the lowest values of the 
deciview index) and 20% most impaired days (the 20% of monitored days 
in a calendar year with the highest amounts of anthropogenic visibility 
impairment).\17\ 40 CFR 51.301. A state must calculate visibility 
conditions for both the 20% clearest and 20% most impaired days for the 
baseline period of 2000-2004 and the most recent five-year period for 
which visibility monitoring data are available (representing current 
visibility conditions). 40 CFR 51.308(f)(1)(i) and (iii). States must 
also calculate natural visibility conditions for the clearest and most 
impaired days,\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 in order 
to reach natural visibility conditions.
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    \17\ This document also refers to the 20% clearest and 20% 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, 
January 10, 2017: ``In the final version of 40 CFR 51.308(f)(1)(ii), 
an occurrence of ``or'' has been corrected to ``and'' to indicate 
that natural visibility conditions for both the most impaired days 
and the clearest days must be based on available monitoring 
information.''
---------------------------------------------------------------------------

    Using the data for the set of most impaired days only, states must 
plot a line between visibility conditions in the baseline period and 
natural visibility conditions for each Class I area to determine the 
URP--the amount of visibility improvement, measured in deciviews, that 
would need to be achieved during each implementation period in order to 
achieve natural visibility conditions by the end of 2064. The URP is 
used in later steps of the reasonable progress analysis for 
informational purposes and to provide a non-enforceable benchmark 
against which to assess a Class I area's rate of visibility 
improvement.\19\ Additionally, in the 2017 RHR Revisions, the EPA 
provided states the option of proposing to adjust the endpoint of the 
URP to account for impacts of anthropogenic sources outside the United 
States and/or impacts of certain types of wildland prescribed fires. 
These adjustments, which must be approved by the EPA, are intended to 
avoid any perception that states should compensate for impacts from 
international anthropogenic sources and to give states the flexibility 
to determine that limiting the use of wildland-prescribed fire is not 
necessary for reasonable progress. 82 FR 3078 at 3107 footnote 116, 
January 10, 2017.
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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 in order to make reasonable progress

[[Page 58183]]

towards the national visibility goal. See 40 CFR 51.308(f)(2)(i). 
Emission reduction measures that are necessary to make reasonable 
progress may be either new, additional control measures for a source, 
or they may be the existing emission reduction measures that a source 
is already implementing. See 2019 Guidance at 43; 2021 Clarifications 
Memo at 8-10. Such measures must be represented by ``enforceable 
emissions limitations, compliance schedules, and other measures'' 
(i.e., any additional compliance tools) in a state's long-term strategy 
in its SIP. 40 CFR 51.308(f)(2).
    Section 51.308(f)(2)(i) provides the requirements for the four-
factor analysis. The first step of this analysis entails selecting the 
sources to be evaluated for emission reduction measures; to this end, 
the RHR requires states to consider ``major and minor stationary 
sources or groups of sources, mobile sources, and area sources'' of 
visibility impairing pollutants for potential four-factor control 
analysis. 40 CFR 51.308(f)(2)(i). A threshold question at this step is 
which visibility impairing pollutants will be analyzed. As 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 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\
---------------------------------------------------------------------------

    \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, May 4, 2016) at 87-88.
---------------------------------------------------------------------------

    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 nonair quality environmental impacts of compliance, and the 
remaining useful life of any existing source subject to such 
requirements.'' CAA 169A(g)(1). The EPA has explained that the four-
factor analysis is an assessment of potential emission reduction 
measures (i.e., control options) for sources; ``use of the terms 
`compliance' and `subject to such requirements' in section 169A(g)(1) 
strongly indicates that Congress intended the relevant determination to 
be the requirements with which sources would have to comply in order to 
satisfy the CAA's reasonable progress mandate.'' 82 FR 3078 at 3091, 
January 10, 2017. Thus, for each source it has selected for four-factor 
analysis,\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 emission 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 emission rate than a source has achieved or could 
potentially achieve using its existing measures should also consider 
lower emission rates as potential control options. That is, a state 
should consider a source's recent actual and projected emission rates 
to determine if it could

[[Page 58184]]

reasonably attain lower emission rates with its existing measures. If 
so, the state should analyze the lower emission rate as a control 
option for reducing emissions. 2021 Clarifications Memo at 7. The EPA's 
recommendations to analyze potential efficiency improvements and 
achievable lower emission rates apply to both sources that have been 
selected for four-factor analysis and those that have forgone a four-
factor analysis on the basis of existing ``effective controls.'' See 
2021 Clarifications Memo at 5, 10.
    After identifying a reasonable set of potential control options for 
the sources it has selected, a state then collects information on the 
four factors with regard to each option identified. The EPA has also 
explained that, in addition to the four statutory factors, states have 
flexibility under the CAA and RHR to reasonably consider visibility 
benefits as an additional factor alongside the four statutory 
factors.\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 
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 emission rate, it may not be 
necessary to have those measures in the long-term strategy in order to 
prevent future emission increases and future visibility impairment. 
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.
---------------------------------------------------------------------------

    \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).
---------------------------------------------------------------------------

    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 the EPA can comprehend and 
evaluate the information and analysis the state relied upon to 
determine what emission reduction measures must be in place to make 
reasonable progress. The technical documentation must include the 
modeling, monitoring, cost, engineering, 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.
---------------------------------------------------------------------------

    \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 51.3108(f)(2)(iv) separately 
provides five ``additional factors'' \26\ that states must consider in 
developing their long-term

[[Page 58185]]

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 regional emissions 
strategies; additional consultations between states outside of RPO 
processes may also occur. If a state, pursuant to consultation, agrees 
that certain measures (e.g., a certain emission limitation) are 
necessary to make reasonable progress at a Class I area, it must 
include those measures in its SIP. 40 CFR 51.308(f)(2)(ii)(A). 
Additionally, the RHR requires that states that contribute to 
visibility impairment at the same Class I area consider the emission 
reduction measures the other contributing states have identified as 
being necessary to make reasonable progress for their own sources. 40 
CFR 51.308(f)(2)(ii)(B). If a state has been asked to consider or adopt 
certain emission reduction measures, but ultimately determines those 
measures are not necessary to make reasonable progress, that state must 
document in its SIP the actions taken to resolve the disagreement. 40 
CFR 51.308(f)(2)(ii)(C). The EPA will consider the technical 
information and explanations presented by the submitting state and the 
state with which it disagrees when considering whether to approve the 
state's SIP. See id.; 2019 Guidance at 53. Under all circumstances, a 
state must document in its SIP submission all substantive consultations 
with other contributing states. 40 CFR 51.308(f)(2)(ii)(C).

D. Reasonable Progress Goals

    Reasonable progress goals ``measure the progress that is projected 
to be achieved by the control measures states have determined are 
necessary to make reasonable progress based on a four-factor 
analysis.'' 82 FR 3078 at 3091, January 10, 2017. Their primary purpose 
is to assist the public and the EPA in assessing the reasonableness of 
states' long-term strategies for making reasonable progress towards the 
national visibility goal. See 40 CFR 51.308(f)(3)(iii) and (iv). States 
in which Class I areas are located must establish two RPGs, both in 
deciviews--one representing visibility conditions on the clearest days 
and one representing visibility on the most anthropogenically impaired 
days--for each area within their borders. 40 CFR 51.308(f)(3)(i). The 
two RPGs are intended to reflect the projected impacts, on the two sets 
of days, of the emission reduction measures the state with the Class I 
area, as well as all other contributing states, have included in their 
long-term strategies for the second implementation period.\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 and of control 
determinations by other states, other on-going emissions changes, a 
particular state's RPGs may not reflect all control measures and 
emissions reductions that are expected to occur by the end of the 
implementation period. The 2019 Guidance provides recommendations 
for addressing the timing of RPG calculations when states are 
developing their long-term strategies on disparate schedules, as 
well as for adjusting RPGs using a post-modeling approach. 2019 
Guidance at 47-48.
---------------------------------------------------------------------------

    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

[[Page 58186]]

under 40 CFR 51.308(f)(2)(i), that no additional emission reduction 
measures would be reasonable to include in its long-term strategy. 40 
CFR 51.308(f)(3)(ii). To this end, 40 CFR 51.308(f)(3)(ii) requires 
that each state contributing to visibility impairment in a Class I area 
that is projected to improve more slowly than the URP provide ``a 
robust demonstration, including documenting the criteria used to 
determine which sources or groups [of] sources were evaluated and how 
the four factors required by paragraph (f)(2)(i) were taken into 
consideration in selecting the measures for inclusion in its long-term 
strategy.'' The 2019 Guidance provides suggestions about how such a 
``robust demonstration'' might be conducted. See 2019 Guidance at 50-
51.
    The 2017 RHR, 2019 Guidance, and 2021 Clarifications Memo also 
explain that projecting an RPG that is on or below the URP based on 
only on-the-books and/or on-the-way control measures (i.e., control 
measures already required or anticipated before the four-factor 
analysis is conducted) is not a ``safe harbor'' from the CAA's and 
RHR's requirement that all states must conduct a four-factor analysis 
to determine what emission reduction measures constitute reasonable 
progress. The URP is a planning metric used to gauge the amount of 
progress made thus far and the amount left before reaching natural 
visibility conditions. However, the URP is not based on consideration 
of the four statutory factors and therefore cannot answer the question 
of whether the amount of progress being made in any particular 
implementation period is ``reasonable progress.'' See 82 FR 3078 at 
3093, 3099-3100, January 10, 2017; 2019 Guidance at 22; 2021 
Clarifications Memo at 15-16.

E. Monitoring Strategy and Other State Implementation Plan Requirements

    Section 51.308(f)(6) requires states to have certain strategies and 
elements in place for assessing and reporting on visibility. Individual 
requirements under this subsection apply either to states with Class I 
areas within their borders, states with no Class I areas but that are 
reasonably anticipated to cause or contribute to visibility impairment 
in any Class I area, or both. A state with Class I areas within its 
borders must submit with its SIP revision a monitoring strategy for 
measuring, characterizing, and reporting regional haze visibility 
impairment that is representative of all Class I areas within the 
state. SIP revisions for such states must also provide for the 
establishment of any additional monitoring sites or equipment needed to 
assess visibility conditions in Class I areas, as well as reporting of 
all visibility monitoring data to the EPA at least annually. Compliance 
with the monitoring strategy requirement may be met through a state's 
participation in the Interagency Monitoring of Protected Visual 
Environments (IMPROVE) monitoring network, which is used to measure 
visibility impairment caused by air pollution at the 156 Class I areas 
covered by the visibility program. 40 CFR 51.308(f)(6), (f)(6)(i) and 
(iv). The IMPROVE monitoring data is used to determine the 20% most 
anthropogenically impaired and 20% clearest sets of days every year at 
each Class I area and tracks visibility impairment over time.
    All states' SIPs must provide for procedures by which monitoring 
data and other information are used to determine the contribution of 
emissions from within the state to regional haze visibility impairment 
in affected Class I areas. 40 CFR 51.308(f)(6)(ii) and (iii). Section 
51.308(f)(6)(v) further requires that all states' SIPs provide for a 
statewide inventory of emissions of pollutants that are reasonably 
anticipated to cause or contribute to visibility impairment in any 
Class I area; the inventory must include emissions for the most recent 
year for which data are available and estimates of future projected 
emissions. States must also include commitments to update their 
inventories periodically. The inventories themselves do not need to be 
included as elements in the SIP and are not subject to EPA review as 
part of the Agency's evaluation of a SIP revision.\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\
---------------------------------------------------------------------------

    \28\ See ``Step 8: Additional requirements for regional haze 
SIPs'' in 2019 Regional Haze Guidance at 55.
    \29\ Id.
---------------------------------------------------------------------------

    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 the EPA or the FLM of an affected Class I area has 
advised a state that additional monitoring is needed to assess 
reasonably attributable visibility impairment, the state must include 
in its SIP revision for the second implementation period an appropriate 
strategy for evaluating such impairment.
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    \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.
---------------------------------------------------------------------------

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

    Section 51.308(f)(5) requires a state's regional haze SIP revision 
to address the requirements of 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 the EPA about a 
state's implementation of its existing long-term strategy and whether 
such implementation is in fact resulting in the expected visibility 
improvement. See 81 FR 26942, 26950 (May 4, 2016), (82 FR 3078 at 3119, 
January 10, 2017). To this end, every state's SIP revision for the 
second implementation period is required to describe the status of 
implementation of all measures included in the state's long-term 
strategy, including BART and reasonable progress emission reduction 
measures from the first implementation period, and the resulting 
emissions reductions. 40 CFR 51.308(g)(1) and (2).
    A core component of the progress report requirements is an 
assessment of changes in visibility conditions on the clearest and most 
impaired days. For second implementation period progress reports, 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)(B), and 
then to calculate the difference between those current conditions and 
baseline (2000-2004) visibility conditions in order to assess progress 
made to date. See 40 CFR 51.308(g)(3)(ii)(B). States must also

[[Page 58187]]

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)(B) and (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) and (f)(5). Changes in emissions should be identified 
by the type of source or activity. Section 51.308(g)(5) also addresses 
changes in emissions since the period addressed by the previous 
progress report and requires states' SIP revisions to include an 
assessment of any significant changes in anthropogenic emissions within 
or outside the state. This assessment must include an explanation of 
whether these changes in emissions were anticipated and whether they 
have limited or impeded progress in reducing emissions and improving 
visibility relative to what the state projected based on its long-term 
strategy for the first implementation period.

G. Requirements for State and Federal Land Manager Coordination

    Clean Air Act section 169A(d) requires that before a state holds a 
public hearing on a proposed regional haze SIP revision, it must 
consult with the appropriate FLM or FLMs; pursuant to that 
consultation, the state must include a summary of the FLMs' conclusions 
and recommendations in the notice to the public. Consistent with this 
statutory requirement, the RHR also requires that states ``provide the 
[FLM] with an opportunity for consultation, in person and at a point 
early enough in the State's policy analyses of its long-term strategy 
emission reduction obligation so that information and recommendations 
provided by the [FLM] can meaningfully inform the State's decisions on 
the long-term strategy.'' 40 CFR 51.308(i)(2). Consultation that occurs 
120 days prior to any public hearing or public comment opportunity will 
be deemed ``early enough,'' but the RHR provides that in any event the 
opportunity for consultation must be provided at least 60 days before a 
public hearing or comment opportunity. This consultation must include 
the opportunity for the FLMs to discuss their assessment of visibility 
impairment in any Class I area and their recommendations on the 
development and implementation of strategies to address such 
impairment. 40 CFR 51.308(i)(2). In order for the EPA to evaluate 
whether FLM consultation meeting the requirements of the RHR has 
occurred, the SIP submission should include documentation of the timing 
and content of such consultation. The SIP revision submitted to the EPA 
must also describe how the state addressed any comments provided by the 
FLMs. 40 CFR 51.308(i)(3). Finally, a SIP revision must provide 
procedures for continuing consultation between the state and FLMs 
regarding the state's visibility protection program, including 
development and review of SIP revisions, five-year progress reports, 
and the implementation of other programs having the potential to 
contribute to impairment of visibility in Class I areas. 40 CFR 
51.308(i)(4).

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

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

    MDE submitted its regional haze SIP for the first implementation 
period to the EPA on February 13, 2012. The EPA approved Maryland's 
first implementation period regional haze SIP submission on July 6, 
2012 (77 FR 39938, July 6, 2012), effective August 6, 2012. EPA's 
approval included the portions of the plan that addressed the 
reasonable progress requirements and Maryland's implementation of Best 
Available Retrofit Technologies (BART) on eligible sources. 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), Maryland was also responsible for submitting a 
five-year progress report as a SIP revision for the first 
implementation period, which it did on August 9, 2017. The EPA approved 
the progress report on November 26, 2018 (83 FR 60363, November 26, 
2018), effective December 26, 2018.

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

    In accordance with CAA sections 169A and the RHR at 40 CFR 
51.308(f), on February 8, 2022, MDE submitted a revision to the 
Maryland SIP to address its regional haze obligations for the second 
implementation period, which runs through 2028. Maryland made its 2020 
Regional Haze SIP submission available for public comment on December 
1, 2021 through January 4, 2022. MDE received and responded to public 
comments and included the comments and responses to those comments in 
their submission.
    The following sections describe Maryland's SIP submission, 
including analyses conducted by MANE-VU and Maryland's determinations 
based on those analyses, Maryland'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. This document also contains EPA's evaluation of 
Maryland's submission against the requirements of the CAA and RHR for 
the second implementation period of the regional haze program.

C. Identification of Class I Areas

    Section 169A(b)(2) of the CAA requires each state in which any 
Class I area is located or ``the emissions from which may reasonably be 
anticipated to cause or contribute to any impairment of visibility'' in 
a Class I area to have a plan for making reasonable progress toward the 
national visibility goal. The RHR implements this statutory requirement 
at 40 CFR 51.308(f), which provides that each state's plan ``must 
address regional haze in each mandatory Class I Federal area located 
within the State and in each mandatory Class I Federal area located 
outside the State that may be affected by emissions from within the 
State,'' and 40 CFR 51.308(f)(2), which requires each state's plan to 
include a long-term strategy that addresses regional haze in such Class 
I areas.
    The EPA explained in the 1999 RHR preamble that the CAA section 
169A(b)(2) requirement that states submit SIPs to address visibility 
impairment establishes ``an `extremely low triggering threshold' in 
determining which States should submit SIPs for regional haze.'' 64 FR 
35714 at 35721, July 1, 1999. In concluding that each of the contiguous 
48 states and the District of Columbia meet this threshold,\31\ the EPA 
relied on ``a large body of evidence demonstrat[ing] that long-range 
transport of fine PM contributes to regional haze,'' id., including 
modeling studies that ``preliminarily

[[Page 58188]]

demonstrated that each State not having a Class I area had emissions 
contributing to impairment in at least one downwind Class I area.'' Id. 
at 35722. In addition to the technical evidence supporting a conclusion 
that each state contributes to existing visibility impairment, the EPA 
also explained that the second half of the national visibility goal--
preventing future visibility impairment--requires having a framework in 
place to address future growth in visibility-impairing emissions and 
makes it inappropriate to ``establish criteria for excluding States or 
geographic areas from consideration as potential contributors to 
regional haze visibility impairment.'' Id. at 35721. Thus, the EPA 
concluded that the agency's ``statutory authority and the scientific 
evidence are sufficient to require all States to develop regional haze 
SIPs to ensure the prevention of any future impairment of visibility, 
and to conduct further analyses to determine whether additional control 
measures are needed to ensure reasonable progress in remedying existing 
impairment in downwind Class I areas.'' Id. at 35722. EPA's 2017 
revisions to the RHR did not disturb this conclusion. See 82 FR 3078 at 
3094, January 10, 2017.
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    \31\ EPA determined that ``there is more than sufficient 
evidence to support our conclusion that emissions from each of the 
48 contiguous states and the District of Columba may reasonably be 
anticipated to cause or contribute to visibility impairment in a 
Class I area.'' 64 FR 35714 at 35721, July 1, 1999. Hawaii, Alaska, 
and the U.S. Virgin Islands must also submit regional haze SIPs 
because they contain Class I areas.
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    Maryland has no mandatory Class I Federal area within its borders, 
but has previously been shown to have sources with emissions that 
impact visibility at downwind mandatory Class I Federal areas. For the 
second implementation period, MANE-VU performed technical analyses \32\ 
to help assess source and state-level contributions to visibility 
impairment and the need for interstate consultation. MANE-VU used the 
results of these analyses to determine which states' emissions ``have a 
high likelihood of affecting visibility in MANE-VU's Class I areas.'' 
\33\ Similar to metrics used in the first implementation period,\34\ 
MANE-VU used a greater than 2 percent of sulfate plus nitrate emissions 
contribution criteria to determine whether emissions from individual 
jurisdictions within the region affected visibility in any Class I 
areas. The MANE-VU analyses for the second implementation period used a 
combination of data analysis techniques, including emissions data, 
distance from Class I areas, wind trajectories, and CALPUFF dispersion 
modeling. Although many of the analyses focused only on SO2 
emissions and resultant particulate sulfate contributions to visibility 
impairment, some also incorporated NOX emissions to estimate 
particulate nitrate contributions.
---------------------------------------------------------------------------

    \32\ The contribution assessment methodologies for MANE-VU Class 
I areas are summarized in Appendix 1 of Maryland's SIP submittal, 
which can be found in the docket, ``Selection of States for MANE-VU 
Regional Haze Consultation (2018).''
    \33\ Id.
    \34\ See docket EPA-R03-OAR-2022-0912 for MANE-VU supporting 
materials.
---------------------------------------------------------------------------

    One MANE-VU analysis used for contribution assessment was CALPUFF 
air dispersion modeling. The CALPUFF model was used to estimate sulfate 
and nitrate formation and transport in MANE-VU and nearby regions 
originating from large electric generating unit (EGU) point sources and 
other large industrial and institutional sources in the eastern and 
central United States. Information from an initial round of CALPUFF 
modeling was collated for the 444 EGUs that were determined to warrant 
further scrutiny based on their emissions of SO2 and 
NOX. The list of EGUs was based on an enhanced ``Q/d'' 
analysis \35\ that considered recent SO2 emissions in the 
eastern United States and an analysis that adjusted previous 2002 MANE-
VU CALPUFF modeling by applying a ratio of 2011 to 2002 SO2 
emissions. This list of sources was then enhanced by including the top 
five SO2 and NOX emission sources for 2011 for 
each state included in the modeling domain. A total of 311 EGU stacks 
(as opposed to individual units) were included in the CALPUFF modeling 
analysis. Initial information was also collected on the 50 industrial 
and institutional sources that, according to 2011 Q/d analysis, 
contributed the most to visibility impact in each Class I area. The 
ultimate CALPUFF modeling run included a total of 311 EGU stacks and 82 
industrial facilities. The summary report for the CALPUFF modeling 
included the top 10 most impacting EGUs and the top 5 most impacting 
industrial/institutional sources for each Class I area and compiled 
those results into a ranked list of the most impacting EGUs and 
industrial sources at MANE-VU Class I areas.\36\
---------------------------------------------------------------------------

    \35\ ``Q/d'' is emissions (Q) in tons per year, typically of one 
or a combination of visibility-impairing pollutants, divided by 
distance to a class I area (d) in kilometers. The resulting ratio is 
commonly used as a metric to assess a source's potential visibility 
impacts on a particular class I area.
    \36\ See docket document, ``2016 MANE VU Source Contribution 
Modeling Report (CALPUFF Modeling of Large EGUs and Industrial 
Sources) (April 4, 2017)''.
---------------------------------------------------------------------------

    Maryland had ten EGU sources \37\ and six industrial/institutional 
sources \38\ that were included in the MANE-VU CALPUFF modeling 
analysis.\39\ The EGU facilities Brandon Shores, Chalk Point, Herbert 
Wagner, and Morgantown were identified as among the Top 25 most 
impactful EGU facilities for Shenandoah National Park Class I area, and 
EGU facility CP Crane was also identified as among the Top 25 most 
impactful EGU facilities for Dolly Sods Wilderness Class I area. EGU 
facilities Brandon Shores, Chalk Point, CP Crane, Herbert Wagner, and 
Morgantown were also among the EGU facilities identified as having the 
Top Impacting EGU stacks. The Luke Paper Company and Sparrows Point 
industrial facilities were identified as among the Top 25 visibility 
impacting industrial/institutional sources for Acadia National Park, 
Brigantine National Wilderness Area, Great Gulf Wilderness, Lye Brook 
Wilderness, Dolly Sods Wilderness, and Shenandoah National Park Class I 
areas. The Indian Head Naval Support Facility was also identified as 
among the Top 25 visibility impacting industrial/institutional sources 
for Dolly Sods Wilderness and Shenandoah National Park.
---------------------------------------------------------------------------

    \37\ Brandon Shores (Unit 1 & Unit 2), CP Crane (Unit 1 & Unit 
2), Chalk Point (Units 1 & 2), Dickerson (Units 1-3), Herbert Wager 
(Unit 3 & Units 1, 2, and 4), and Morgantown (Unit 1 and Unit 2).
    \38\ Luke Paper Company (Unit 0018, Unit 0019, and Unit 0235), 
Naval Support Facility Indian Head, and Sparrows Point, LLC (Unit 
0939 and Unit 0941).
    \39\ See docket document, ``2016 MANE VU Source Contribution 
Modeling Report (CALPUFF Modeling of Large EGUs and Industrial 
Sources) (April 4, 2017)''.
---------------------------------------------------------------------------

    In its submittal, Maryland indicates that Brandon Shores Generating 
Station has agreed via legal consent agreement to cease coal combustion 
at the site by 2026.\40\ Maryland indicates that Chalk Point Generation 
Station ceased coal operations in 2021 and closed, and that Maryland 
subsequently filed a Retired Unit Exemption form with EPA, specifying 
that the Chalk Point units identified are permanently shut down and 
cannot be restarted, and that a new owner would be required to obtain 
all new permits.\41\ Maryland also indicates that Herbert Wagner 
Generating Station has agreed to cease coal combustion by 2026; MDE and 
Herbert Wagner owner/operator Raven Power, Fort Smallwood LLC, entered 
into a legal consent order requiring Raven Power to cease coal 
combustion at Herbert Wager no later than January 1, 2026.\42\ Maryland

[[Page 58189]]

included the consent order as part of its SIP submittal. Maryland also 
indicates that CP Crane Generating Station has disabled its coal 
boilers and agreed via legal consent agreement to never again stockpile 
or burn coal at the facility.\43\ Maryland further indicates that the 
Luke Paper Company industrial facility has ceased operations, closed 
and relinquished their air permits as of May 29, 2020; \44\ that the 
Sparrows Point industrial facility was retired as of December 31, 2012; 
\45\ and that the primary emissions units at the Indian Head Naval 
Support Facility, which consisted of three coal- and No. 6 fuel oil-
fired boilers at the Goddard Steam Plant, were permanently shut down in 
2014.\46\
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    \40\ See Section 2.4 of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022), and docket 
documents ``MDE SO2 2010 NAAQS SIP for Baltimore and Anne 
Arundel NA (January 31, 2020)'', and ``MDE SO2 2010 NAAQS 
SIP for Baltimore and Anne Arundel NA (January 31, 2020)--Appendix 
B--Consent Orders, Permits, and Plan Approvals''.
    \41\ See docket document, ``MDE EPA Chalk Point Units 1&2 
Retired Unit Exemption Forms 6-4-21 (June 4, 2021)''.
    \42\ See Appendix 19, ``Herbert A. Wagner Generating Station 
Consent Order''.
    \43\ See Section 2.6.1 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022), and 
docket documents ``MDE SO2 2010 NAAQS SIP for Baltimore 
and Anne Arundel NA (January 31, 2020)'', and ``MDE SO2 
2010 NAAQS SIP for Baltimore and Anne Arundel NA (January 31, 
2020)--Appendix B--Consent Orders, Permits, and Plan Approvals''.
    \44\ See docket documents, ``Verso Luke Paper--Luke MD Title V 
Permit Termination (May 7, 2020)'' and ``Verso Luke Paper--Verso 
Luke Close Out Letter (May 8, 2020)''.
    \45\ See docket document, ``MDE Sparrows Point Administrative 
Consent Order (September 12, 2014)''.
    \46\ See docket document, ``MDE EPA Indian Head Boiler 
Decommision letter (January 29, 2016)''.
---------------------------------------------------------------------------

    The second MANE-VU contribution analysis used a meteorologically 
weighted Q/d calculation to assess states' contributions to visibility 
impairment at MANE-VU Class I areas.\47\ This analysis focused 
predominantly on SO2 emissions and used cumulative 
SO2 emissions from a source and a state for the variable 
``Q,'' and the distance of the source or state to the IMPROVE monitor 
receptor at a Class I area as ``d.'' The result is then multiplied by a 
constant (Ci), which is determined based on the prevailing 
wind patterns. MANE-VU selected a meteorologically weighted Q/d 
analysis as an inexpensive initial screening tool that could easily be 
repeated to determine which states, sectors, or sources have a larger 
relative impact and warrant further analysis. MANE-VU updated its 
analysis in 2016 using 2011 emissions and 2018 projected emissions, 
which Maryland included as part of its submittal. MANE-VU's analysis 
estimated Maryland's 2018 sulfate contribution at 3.77% at Acadia 
National Park, 8.89% at Brigantine Wilderness, 3.36% at Great Gulf 
3.80% at Lye Brook, and 3.35% at Moosehorn Class I areas based on 
maximum daily impact.\48\ Although MANE-VU did not originally estimate 
nitrate impacts, the MANE-VU Q/d analysis was subsequently extended to 
account for nitrate contributions from NOX emissions and to 
approximate the nitrate impacts from area and mobile sources. MANE-VU 
therefore developed a ratio of nitrate to sulfate impacts based on the 
previously described CALPUFF modeling and applied those to the sulfate 
Q/d results in order to derive nitrate contribution estimates. Several 
states did not have CALPUFF nitrate to sulfate ratio results, however, 
because there were no point sources modeled with CALPUFF.
---------------------------------------------------------------------------

    \47\ See docket document, ``MANE-VU Contributions to Regional 
Haze in the Northeast and Mid-Atlantic United States (August 
2006)''.
    \48\ See ``Table 2-2: Q/d results using 2011 and 2018 inventory 
data for 32 states'', of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    In order to develop a final set of contribution estimates, MANE-VU 
weighted the results from both the Q/d and CALPUFF analyses. The MANE-
VU mass-weighted sulfate and nitrate contribution results were reported 
for the MANE-VU Class I areas (the Q/d summary report included results 
for several non-MANE-VU areas as well). If a state's contribution to 
sulfate and nitrate concentrations at a particular Class I area was 2 
percent or greater, MANE-VU regarded that state as contributing to 
visibility impairment in that area. According to MANE-VU's analyses, 
sources in Maryland were found to contribute to visibility impairment 
at all seven downwind MANE-VU Class I areas,\49\ as well as VISTA Class 
I areas including James River Face and Shenandoah National Park in 
Virginia and Dolly Sods Wilderness and Otter Creek Wilderness in West 
Virginia.\50\ MANE-VU determined that modeled emissions sources that 
have the potential for 3.0 Mm-1 or greater visibility 
impacts at any MANE-VU Class I area should perform a four-factor 
analysis for reasonable installation or upgrade to emissions controls. 
Maryland indicated in its submittal that it agrees with MANE-VU's 
approach and assessment.
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    \49\ Acadia National Park, Moosehorn National Wildlife Refuge, 
and Roosevelt Campobello International Park in Maine; Brigantine 
Wilderness in New Jersey; Great Gulf Wilderness and Presidential 
Range-Dry River Wilderness in New Hampshire; and Lye Brook 
Wilderness in Vermont.
    \50\ See docket document, ``2016 MANE-VU Source Contribution 
Modeling Report (April 4, 2017),'' Tables 1 through 33.
---------------------------------------------------------------------------

    As explained above, the EPA concluded in the 1999 RHR that ``all 
[s]tates contain sources whose emissions are reasonably anticipated to 
contribute to regional haze in a Class I area,'' 64 FR 35714 at 35721, 
July 1, 1999, and this determination was not changed in the 2017 RHR. 
Critically, the statute and regulation both require that the cause-or-
contribute assessment consider all emissions of visibility-impairing 
pollutants from a state, as opposed to emissions of a particular 
pollutant or emissions from a certain set of sources. Consistent with 
these requirements, the 2019 Guidance makes it clear that ``all types 
of anthropogenic sources are to be included in the determination'' of 
whether a state's emissions are reasonably anticipated to result in any 
visibility impairment. 2019 Guidance at 8.
    First, the screening analyses on which MANE-VU relied are useful 
for certain purposes. MANE-VU used information from its technical 
analysis to rank the largest contributing states to sulfate and nitrate 
impairment in five Class I areas within MANE-VU states and three 
additional, nearby Class I areas.\51\ The rankings were used to 
determine upwind states that were deemed important to include in state-
to-state consultation (based on an identified impact screening 
threshold). Additionally, large individual source impacts were used to 
target MANE-VU control analysis ``Asks'' \52\ of states and sources 
both within and upwind of MANE-VU.\53\ The EPA finds the nature of the 
analyses generally appropriate to support decisions on states with 
which to consult. However, we have cautioned that source selection 
methodologies that target the largest regional contributors to 
visibility impairment across multiple states may not be reasonable for 
a particular state if it results in few or no sources being selected 
for subsequent analysis. 2021 Clarifications Memo at 3.
---------------------------------------------------------------------------

    \51\ The Class I areas analyzed were Acadia National Park in 
Maine, Brigantine Wilderness in New Jersey, Great Gulf Wilderness in 
New Hampshire, Lye Brook Wilderness in Vermont, Moosehorn Wilderness 
in Maine, Shenandoah National Park in Virginia, James River Face 
Wilderness in Virginia, and Dolly Sods/Otter Creek Wildernesses in 
West Virginia.
    \52\ As explained more fully in Section IV.E.1 of this document, 
MANE-VU refers to each of the components of its overall strategy as 
an ``Ask ``of its member states.
    \53\ The MANE-VU Consultation Report (Appendix 7) explains that 
``[t]he objective of this technical work was to identify states and 
sources from which MANE-VU will pursue further analysis. This 
screening was intended to identify which states to invite to 
consultation, not a definitive list of which states are 
contributing.''
---------------------------------------------------------------------------

    With regard to the analysis and determinations regarding Maryland's 
contribution to visibility impairment at out-of-state Class I areas, 
the MANE-VU technical work focuses on the magnitude of visibility 
impacts from certain Maryland emissions on downwind Class I areas. 
However, the analyses did not account for all

[[Page 58190]]

emissions and all components of visibility impairment (e.g., primary PM 
emissions, and impairment from fine PM, elemental carbon, and organic 
carbon). In addition, Q/d analyses with a relatively simplistic 
accounting for wind trajectories and CALPUFF applied to a very limited 
set of EGUs and major industrial sources of SO2 and 
NOX are not scientifically rigorous tools capable of 
evaluating contribution to visibility impairment from all emissions in 
a state. While Maryland noted that contributions from other states are 
larger than its own, we again clarify that each state is obligated 
under the CAA and RHR to address regional haze visibility impairment 
resulting from emissions from within the state, irrespective of whether 
another state's contribution is greater. See 2021 Clarifications Memo 
at 3. Additionally, we note that the 2 percent or greater sulfate-plus-
nitrate threshold used to determine whether Maryland emissions 
contribute to visibility impairment at a particular Class I area may be 
higher than what EPA believes is an ``extremely low triggering 
threshold'' intended by the statute and regulations. In sum, based on 
the information provided, it is clear that emissions from Maryland 
contribute to visibility impairment at out-of-state Class I areas.
    Regardless, we note that Maryland did determine that sources and 
emissions within the state contribute to visibility impairment at out-
of-state Class I areas. Furthermore, the state took part in the 
emission control strategy consultation process as a member of MANE-VU. 
As part of that process, MANE-VU developed a set of emissions reduction 
measures identified as being necessary to make reasonable progress in 
the five MANE-VU Class I areas. This strategy consists of six Asks for 
states within MANE-VU and five Asks for states outside the region that 
were found to impact visibility at Class I areas within MANE-VU.\54\ 
Maryland's submittal discusses each of the Asks and explains why or why 
not each is applicable and how it has complied with the relevant 
components of the emissions control strategy MANE-VU has laid out for 
its states. Maryland worked with MANE-VU to determine potential 
reasonable measures that could be implemented by 2028, considering the 
cost of compliance, the time necessary for compliance, the energy and 
non-air quality environmental impacts, and the remaining useful life of 
any potentially affected sources. As discussed in further detail below, 
the EPA is proposing to find that Maryland has submitted a regional 
haze plan that meets the requirements of 40 CFR 51.308(f)(2) related to 
the development of a long-term strategy. Although we have concerns 
regarding some aspects of MANE-VU's technical analyses supporting 
states' contribution determinations, we propose to find that Maryland 
has satisfied the applicable requirements for making reasonable 
progress towards natural visibility conditions in Class I areas that 
may be affected be emissions from the state.
---------------------------------------------------------------------------

    \54\ See docket documents, ``MANE-VU Intra-Regional Ask Final 8-
25-2017 (August 25, 2017)'' and ``MANE-VU Inter-Regional Ask Final 
8-25-2017 (August 25, 2017).
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D. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress

    Section 51.308(f)(1) requires states to determine the following for 
``each mandatory Class I Federal area located within the State'': 
baseline visibility conditions for the most impaired and clearest days, 
natural visibility conditions for the most impaired and clearest days, 
progress to date for the most impaired and clearest days, the 
differences between current visibility conditions and natural 
visibility conditions, and the URP. This section also provides the 
option for states to propose adjustments to the URP line for a Class I 
area to account for visibility impacts from anthropogenic sources 
outside the United States and/or the impacts from wildland prescribed 
fires that were conducted for certain, specified objectives. 40 CFR 
51.308(f)(1)(vi)(B).
    Maryland does not have any mandatory Class I areas within its 
borders; therefore, Section 51.308(f)(1) and its requirements do not 
apply.

E. Long-Term Strategy for Regional Haze

1. Maryland's Response to the Six MANE-VU Asks
    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 
document, reasonable progress is achieved when all states contributing 
to visibility impairment in a Class I area are implementing the 
measures determined--through application of the four statutory factors 
to sources of visibility impairing pollutants--to be necessary to make 
reasonable progress. 40 CFR 51.308(f)(2)(i). Each state's long-term 
strategy must include the enforceable emission limitations, compliance 
schedules, and other measures that are necessary to make reasonable 
progress. 40 CFR 51.308(f)(2). All new (i.e., additional) measures that 
are the outcome of four-factor analyses are necessary to make 
reasonable progress and must be in the long-term strategy. If the 
outcome of a four-factor analysis and other measures necessary to make 
reasonable progress is that no new measures are reasonable for a 
source, that source's existing measures are necessary to make 
reasonable progress, unless the state can demonstrate that the source 
will continue to implement those measures and will not increase its 
emission rate. Existing measures that are necessary to make reasonable 
progress must also be 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).
    The following section summarizes how Maryland's SIP submission 
addressed the requirements of 40 CFR 51.308(f)(2)(i); specifically, it 
describes MANE-VU's development of the six Asks and how Maryland 
addressed each. The EPA's evaluation of Maryland's SIP revision with 
regard to the same is contained in the following Section IV.E.2 of this 
document. Maryland's SIP submission describes how it plans to meet the 
long-term strategy requirements defined by the state and MANE-VU and 
provides that ``[t]hese long-term strategies are referred to as the 
`Asks'.'' \55\
---------------------------------------------------------------------------

    \55\ See MD Regional Haze SIP submission Section 2.3 (Page 8).
---------------------------------------------------------------------------

    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). Where an RPO has performed source 
selection and/or four-factor analyses (or considered the five 
additional factors in 40 CFR 51.308(f)(2)(iv)) for its member states, 
those states may rely on the RPO's analyses for the purpose of 
satisfying the requirements of 40 CFR 51.308(f)(2)(i) so long as the 
states have

[[Page 58191]]

a reasonable basis to do so and all state participants in the RPO 
process have approved the technical analyses. 40 CFR 51.308(f)(3)(iii). 
States may also satisfy the requirement of 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.
    Maryland is a member of the MANE-VU RPO and participated in the 
RPO's regional approach to developing a strategy for making reasonable 
progress towards the national visibility goal in the MANE-VU Class I 
areas. MANE-VU's strategy includes a combination of: (1) measures for 
certain source sectors and groups of sectors that the RPO determined 
were reasonable for states to pursue, and (2) a request for member 
states to conduct four-factor analyses for individual sources that it 
identified as contributing to visibility impairment. MANE-VU refers to 
each of the components of its overall strategy as an Ask of its member 
states. On August 25, 2017, the Executive Director of MANE-VU, on 
behalf of the MANE-VU states and tribal nations, signed a statement 
that identifies six emission reduction measures that comprise the Asks 
for the second implementation period.\56\ The Asks were ``designed to 
identify reasonable emission reduction strategies that must be 
addressed by the states and tribal nations of MANE-VU through their 
regional haze SIP updates.'' \57\ The statement explains that ``[i]f 
any State cannot agree with or complete a Class I State's Asks, the 
State must describe the actions taken to resolve the disagreement in 
the Regional Haze SIP.'' \58\
---------------------------------------------------------------------------

    \56\ See Appendix 8, ``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 Regional 
Haze Implementation Period (2018-2028), (August 2017); and Appendix 
7 ``MANE-VU Regional Haze Consultation Report'' (July 27, 2018).''
    \57\ Id.
    \58\ Id.
---------------------------------------------------------------------------

    MANE-VU's recommendations as to the appropriate control measures 
were based on technical analyses documented in the RPO's reports and 
included as appendices to or referenced in Maryland's regional haze SIP 
submission. One of the initial steps of MANE-VU's technical analysis 
was to determine which visibility-impairing pollutants should be the 
focus of its efforts for the second implementation period. In the first 
implementation period, MANE-VU determined that sulfates were the most 
significant visibility impairing pollutant at the region's Class I 
areas. To determine the impact of certain pollutants on visibility at 
Class I areas for the purpose of second implementation period planning, 
MANE-VU conducted an analysis comparing the pollutant contribution on 
the clearest and most impaired days in the baseline period (2000-2004) 
to the most recent period (2012-2016) \59\ at MANE-VU and nearby Class 
I areas. MANE-VU found that while SO2 emissions were 
decreasing and visibility was improving, sulfates still made up the 
most significant contribution to visibility impairment at MANE-VU and 
nearby Class I areas. According to the analysis, NOX 
emissions have begun to play a more significant role in visibility 
impacts in recent years. The technical analyses used by Maryland are 
included or referenced in their submission, and are as follows:
---------------------------------------------------------------------------

    \59\ The period of 2012-2016 was the most recent period for 
which data was available at the time of analysis.
---------------------------------------------------------------------------

     Selection of States for MANE-VU Regional Haze Consultation 
(2018) (MANE-VU, September 2017) (Appendix 1);
     Contributions to Regional Haze in the Northeast and Mid-
Atlantic United States: Preliminary Update through 2007 (NESCAUM, March 
2012); \60\
---------------------------------------------------------------------------

    \60\ See docket document, NESCAUM--Contributions to Regional 
Haze Preliminary Update Through 2007 (March 21, 2012)
---------------------------------------------------------------------------

     MANE-VU Updated Q/d*C Contribution Assessment (MANE-VU, 
April 2016) (Appendix 3);
     2016 MANE-VU Source Contribution Modeling Report--CALPUFF 
Modeling of Large Electrical Generating Units and Industrial Sources 
(MANE-VU, May 2006) (Appendix 4);
     Assessment of Reasonable Progress for Regional Haze in 
MANE-VU Class I areas (referred to as the MACTEC Report) MACTEC (July 
2007); \61\
---------------------------------------------------------------------------

    \61\ See docket document, ``Assessment of Reasonable Progress 
for Regional Haze In MANE-VU Class I Areas (July 2007) (MACTEC 
Reasonable Progress Report)''
---------------------------------------------------------------------------

     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 Regional Haze Implementation Period 
(2018-2028) (August 2017); \62\
---------------------------------------------------------------------------

    \62\ See docket document, ``MANE-VU Intra-Regional Ask Final 
(August 25, 2017)''.
---------------------------------------------------------------------------

     Statement of the Mid-Atlantic/Northeast Visibility Union 
(MANE-VU) 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) (Appendix 8);
     Technical Support Document for the 2011 Northeastern U.S. 
Gamma Emission Inventory (January 2018) (Appendix 10);
     Ozone Transport Commission/Mid-Atlantic Northeastern 
Visibility Union 2011 Based Modeling Platform Support Document--October 
2018 Update (October 2018) (Appendix 11);
     The Nature of Fine Particle and Regional Haze Air Quality 
Problems in the MANE-VU Region: A Conceptual Description (NESCAUM, 
November 2006, Revised August 2010) (Appendix 12);
     Mid-Atlantic/Northeast U.S. Visibility Data 2004-2017 (2nd 
RH SIP Metrics) (MANE-VU, December 2018) (Appendix 13);
     Additional MANE-VU documentation for establishing 3.0 
Mm-1 Threshold (Appendix 17);
     20% Most Impaired Days Based on Deciviews, as Detailed in 
Recommendation on Approaches to Selecting the 20% Most Impaired Days 
(March 2, 2017) (Appendix 18);
     Technical Support Document on Measures to Mitigate the 
Visibility Impacts of Construction Activities in the MANE-VU Region 
(MANE-VU, September 2006); \63\
---------------------------------------------------------------------------

    \63\ See docket document, ``MANE-VU TSD on Measures to Mitigate 
the Visibility Impacts of Construction Activities in the MANE-VU 
Region (September 2006).''
---------------------------------------------------------------------------

     Baseline and Natural Background Visibility Conditions 
(NESCAUM, December 2006); \64\
---------------------------------------------------------------------------

    \64\ See docket document ``NESCAUM--Baseline and Natural 
Background Visibility Conditions (December 2006).''
---------------------------------------------------------------------------

     2016 Updates to the Assessment of Reasonable Progress for 
Regional Haze in MANE-VU Class I Areas, January 31, 2016 (MARAMA, 
January 31, 2016); \65\
---------------------------------------------------------------------------

    \65\ See docket document, ``2016 Updates to the Assessment of 
Reasonable Progress for Regional Haze in MANE-VU Class I Areas 
(January 31, 2016).''
---------------------------------------------------------------------------

    To support development of the Asks, MANE-VU gathered information on 
the four statutory factors for six source sectors it determined, based 
on an examination of annual emission inventories, ``had emissions that 
were reasonabl[y] anticipated to contribute to visibility degradation 
in MANE-VU:'' electric generating units (EGUs), industrial/commercial/
institutional boilers (ICI boilers), cement kilns, heating oil, 
residential wood combustion, and outdoor wood combustion.\66\ MANE-VU 
also collected data on individual sources within the EGU, ICI boiler, 
and cement kiln

[[Page 58192]]

sectors.\67\ Information for the six sectors included explanations of 
technically feasible control options for SO2 or 
NOX, illustrative cost-effectiveness estimates for a range 
of model units and control options, sector-wide cost considerations, 
potential time frames for compliance with control options, potential 
energy and non-air-quality environmental impacts of certain control 
options, and how the remaining useful lives of sources might be 
considered in a control analysis.\68\ Source-specific data included 
SO2 emissions \69\ and existing controls \70\ for certain 
existing EGUs, ICI boilers, and cement kilns. MANE-VU considered this 
information on the four factors as well as the analyses developed by 
the RPO's Technical Support Committee when it determined specific 
emission reduction measures that were found to be reasonable for 
certain sources within two of the sectors it had examined--EGUs and ICI 
boilers. The Asks were based on this analysis and looked to either 
optimize the use of existing controls, have states conduct further 
analysis on EGU or ICI boilers with considerable visibility impacts, 
implement low sulfur fuel standards, or lock-in lower emission rates.
---------------------------------------------------------------------------

    \66\ See docket document ``MANE-VU Four Factor Data Collection 
Memo (March 30, 2017)'' at 1.
    \67\ See docket document, ``2016 Updates to the Assessment of 
Reasonable Progress for Regional Haze in MANE-VU Class I Areas 
(January 31, 2016).''
    \68\ Id.
    \69\ See docket document ``MANE-VU Four Factor Data Collection 
Memo (March 30, 2017).''
    \70\ See docket document ``MANE-VU Status of the Top 167 Stacks 
from the 2008 MANE-VU Ask (July 2016).''
---------------------------------------------------------------------------

    MANE-VU Ask 1 requests 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''.\71\ In its submission, Maryland stated that COMAR 
21.11.27--Emission Limitations for Power Plants (Maryland Healthy Air 
Act) ``caps NOX emissions on an ozone season and annual 
basis for each coal-fired EGU in Maryland.'' In addition, Maryland also 
stated that COMAR 26.11.40--NOX Ozone Season Emission Caps for Non-
trading Large NOX Units ``assures optimization of post-combustion 
(Selective Catalytic Reduction (SCR) and Selective Non-Catalytic 
Reduction (SNCR)) NOX controls on coal-fired EGUs and sets 
NOX Indicator Rates for each unit to assure optimization.'' 
\72\ Maryland credited these regulations with ``reducing annual 
NOX mass emissions by almost 95% compared to 2002 levels.'' 
\73\ Regarding SO2 emission controls, Maryland stated that 
COMAR 21.11.27--Emission Limitations for Power Plans (Maryland Healthy 
Air Act) ``caps SO2 emissions limits on an annual basis for 
each coal-fired EGU in Maryland. All non-fluidized bed base load coal-
fired units are equipped with Flue Gas Desulfurization (FGD) except 
one. H.A. Wagner Unit 3 is the only coal-fired EGU not equipped with an 
FGD. H.A. Wagner Unit 3 is named as a unit requiring a four-factor 
analysis and is analyzed further in Section 2.5.2.'' Maryland also 
stated that permit limits associated with a federally enforceable 
consent order for the Anne Arundel and Baltimore County SO2 
nonattainment area include SO2 emission limits. Taken 
together, Maryland credited these requirements with ``reducing the 
annual SO2 mass emissions by over 95% compared to 2002 
levels''.\74\ Maryland therefore concluded it is meeting Ask 1.
---------------------------------------------------------------------------

    \71\ See Appendix 7, ``MANE-VU Regional Haze Consultation Report 
(July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
    \72\ See Section 2.5.1 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
    \73\ See Table 2-8, Figure 2-3, and Figure 2-4 of the MD 
Regional Haze SIP for the Second Implementation Period 2018-2028 
(February 8, 2022).
    \74\ See Table 2-7 and Figure 2-3 of the MD Regional Haze SIP 
for the Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    MANE-VU Ask 2 requests that states ``perform a four-factor analysis 
for reasonable installation or upgrade to emissions controls'' at 
``emission sources modeled by MANE-VU that have the potential for 3.0 
Mm-1 or greater visibility impacts at any MANE-VU Class I 
area, as identified by MANE-VU contribution analyses''. MANE-VU 
developed its Ask 2 list of sources for analysis by performing modeling 
and identifying facilities with the potential for 3.0 inverse 
megameters (Mm-1) or greater impacts on visibility at any 
Class I area in the MANE-VU region. MANE-VU identified emission sources 
at the Herbert A. Wagner Generating Facility in Anne Arundel County, 
Maryland and at the Verso Luke Paper Company facility in Allegany 
County, Maryland as having the potential for 3.0 Mm-1 or 
greater visibility impacts at any MANE-VU Class I area; \75\ 
specifically, Unit 3 at Herbert A. Wagner Generating Facility and Units 
001-0011-3-0018 and 001-0011-3-0019 at Verso Luke Paper Company. 
Maryland stated that ``Luke Paper Company ceased operations, closed, 
and relinquished their air permits'', and that this information was 
shared in a transmittal letter to EPA dated May 29, 2020 and included 
in an attainment designation request letter.\76\ In addition, Maryland 
also stated that, after requesting a four-factor analysis for Herbert 
A. Wagner Unit 3 from the facility's owner/operator, ``the parent 
company to the H.A. Wagner Generating Station publicly announced a 
strategic repositioning of the facility that would eliminate the use of 
coal. The owners of the H.A. Wagner Generating Station have agreed and 
signed a legal consent order with [MDE] to cease the combustion of coal 
by 2026 . . . Therefore, according to the statutory factor of remaining 
useful life for this facility, further control is not reasonable . . . 
A four-factor analysis of H.A. Wagner Unit 3 similarly concludes that 
no additional controls would effectively control SO2 and 
NOX emissions at this facility since the remaining useful 
life of the coal-fired unit is approximately 4\1/2\ years''.\77\ Given 
the remaining useful life of this source, and the closure of Luke Paper 
Company, Maryland concluded that no further action is necessary to 
satisfy Ask 2.\78\
---------------------------------------------------------------------------

    \75\ See Appendix 4, ``2016 MANE VU Source Contribution Modeling 
Report: CALPUFF Modeling of Large Electrical Generating Units and 
Industrial Sources (April 4, 2017)''.
    \76\ See docket documents, ``Verso Luke Paper--Luke MD Title V 
Permit Termination (May 7, 2020)'' and ``Verso Luke Paper--Verso 
Luke Close Out Letter (May 8, 2020)''.
    \77\ See Appendix 19, Herbert A. Wagner Generating Station 
Consent Order.
    \78\ See Section 2.5.2 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    MANE-VU Ask 3 requests that, for ``each MANE-VU state that has not 
yet fully adopted an ultra-low fuel oil standard as requested by MANE-
VU in 2007'', to ``pursue this standard as expeditiously as possible 
and before 2028, depending on supply availability''. The Ask includes 
percent by weight standards for #2 distillate oil (0.0015% sulfur by 
weight or 15 ppm), #4 residual oil (0.25-0.5% sulfur by weight), and #6 
residual oil (0.3-0.5% sulfur by weight). On October 3, 2014, Maryland 
adopted a rule \79\ to modify the sulfur-in-fuel limits in accordance 
with the MANE-VU Ask. This rule lowered the sulfur content of all 
distillate fuel oils (#2 fuel oil and lighter) to 500 ppm (0.05% by 
mass) on and after July 1, 2016; this rule was subsequently amended 
\80\ to lower the required sulfur content of all distillate fuel oils 
(#2 fuel oil and lighter) to 15

[[Page 58193]]

ppm (0.0015% by mass) on and after July 1, 2019. Maryland therefore 
concluded that it is meeting Ask 3.
---------------------------------------------------------------------------

    \79\ 41:20 Md. R. 1111 (Maryland Register, Volume 41, Issue 20, 
dated October 3, 2014), effective October 13, 2014.
    \80\ 45:24 Md. R. 1162 (Maryland Register, Volume 45, Issue 24, 
dated November 26, 2018), effective December 6, 2018.
---------------------------------------------------------------------------

    MANE-VU Ask 4 requests that states ``pursue updating permits, 
enforceable agreements, and/or rules to lock-in lower emission rates 
for SO2, NOX, and PM'' at ``EGUs and other large 
point emission sources larger than 250 MMBTU per hour heat input that 
have switched to lower emitting fuels''. Ask 4 also states that ``the 
permit, enforceable agreement, and/or rule can allow for suspension of 
the lower emission rate during natural gas curtailment''. Maryland's 
SIP submittal states that ``EGUs and other large point emission sources 
that have switched operations to lower emitting fuels are already 
locked into the lower emission rates for NOX, 
SO2, and PM by permits, enforceable agreements, and/or 
rules. These units are required to amend their permits through the New 
Source Review (NSR) process if they plan to switch back to coal or 
another fuel that will increase emissions. A change in fuel, unless 
already allowed in the permit, would be a modification.'' \81\ 
Maryland's submittal also states that ``COMAR 26.11.02.02 requires that 
a permit to construct and an approval from MDE is required before 
construction or modification of a source.'' Maryland therefore 
concluded it is meeting Ask 4.
---------------------------------------------------------------------------

    \81\ See COMAR 26.11.01.01, defining ``Modify'' or 
``Modification'' to mean ``any physical change in, or change in the 
operation of, a source or installation which causes a change in the 
quantity, nature or characteristics of emissions from the source or 
installation. However, this term excludes routine maintenance and 
routine repair, and increases in the hours of operation or in the 
production rate, unless these increases would be prohibited under 
any permit or approval conditions adopted by the Department.''
---------------------------------------------------------------------------

    MANE-VU Ask 5 requests that MANE-VU states, ``where emission rules 
have not been adopted, control NOX emissions for peaking 
combustion turbines that have the potential to operate on high electric 
demand days'' by either: ``(a) Striving to meet NOX 
emissions standards of no greater than 22 ppm at 15% O2 for natural gas 
and 42 ppm at 15% O2 for fuel oil but at a minimum meet NOX 
emission standards of no greater than 42 ppm at 15% O2 for natural gas 
and 96 ppm at 15% O2 for fuel oil'', or ``(b) Performing a four-factor 
analysis for reasonable installation of or upgrade to emission 
controls'', or ``(c) Obtaining equivalent emission reductions on high 
electric demand days.'' \82\ Maryland elected to perform a four-factor 
analysis for reasonable installation of or upgrade to emission controls 
for sources that met the definition of combustion turbines that have 
the potential to operate on high electric demand days (HEDD),\83\ and 
determined that it would not be technically feasible or cost effective 
to implement additional controls at this time. Maryland therefore 
concluded it is meeting Ask 5.
---------------------------------------------------------------------------

    \82\ See Appendix 7, ``MANE-VU Regional Haze Consultation Report 
(July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
    \83\ See Section 2.5.5 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    MANE-VU Ask 6, the last Ask, requests that ``each State should 
consider and report in their SIP measures or programs to: a) decrease 
energy demand through the use of energy efficiency, and b) increase the 
use within their state of Combined Heat and Power (CHP) and other clean 
Distributed Generation technologies including fuel cells, wind, and 
solar''.\84\ Maryland stated in its SIP submittal that the electricity 
generation strategy in the state's 2030 Greenhouse Gas Reduction Act 
(GGRA) Plan 85 86 is designed to achieve 100% Clean and 
Renewable Electricity by 2040 by both deploying energy through the 
existing Renewable Portfolio Standard (RPS) and the proposed Clean and 
Renewable Energy Standard (CARES), and by capping and reducing 
emissions through the Regional Greenhouse Gas Initiative 
(RGGI).87 88 Maryland's RPS requires Maryland electric 
utilities to purchase increasingly large proportions of Maryland's 
electricity from renewable energy sources like solar, wind, hydropower, 
and qualifying biomass, with a current RPS goal of 50% clean 
electricity by 2030 and 100% clean electricity by 2040. Maryland states 
that these goals rely on both renewable energy and additional zero- and 
low-carbon electricity sources to meet that goal where most cost-
effective, including Maryland solar power beyond current RPS 
requirements, new efficient CHP systems in Maryland buildings, new 
nuclear power, and natural gas or qualifying biomass power plants with 
carbon capture and storage. Maryland further states that, although RGGI 
is designed to reduce carbon dioxide emissions, other benefits in terms 
of NOX and SO2 are realized through energy 
efficiency promotion, CHP deployment, and additional deployment of 
renewable energy sources, including offshore wind power and community 
solar generation.\89\ Maryland therefore concludes that it is meeting 
Ask 6.
---------------------------------------------------------------------------

    \84\ See Appendix 7, ``MANE-VU Regional Haze Consultation Report 
(July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
    \85\ See docket document, ``MDE The 2030 Greenhouse Gas 
Emissions Reduction Act (GGRA) Plan (February 19, 2021)''.
    \86\ mde.maryland.gov/programs/air/ClimateChange/Pages/Greenhouse-Gas-Emissions-Reduction-Act-(GGRA)-Plan.aspx.
    \87\ www.rggi.org/.
    \88\ www.rggiprojectseries.org/.
    \89\ See Section 2.5.6 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

2. The EPA's Evaluation of Maryland's Response to the Six MANE-VU Asks 
and Compliance With Sec.  51.308(f)(2)(i)
    The EPA is proposing to find that Maryland 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. We 
are proposing to find that Maryland has satisfied the four-factor 
analysis requirement through its analysis and actions to address MANE-
VU Ask 2 and Ask 5. We also propose to find that Maryland reasonably 
concluded that it satisfied all six Asks.
    As explained above, Maryland relied on MANE-VU's technical analyses 
and framework (i.e., the Asks) to select sources and form the basis of 
its long-term strategy. MANE-VU conducted an inventory analysis to 
identify the source sectors that produced the greatest amount of 
SO2 and NOX emissions in 2011; inventory data 
were also projected to 2018. Based on this analysis, MANE-VU identified 
the top-emitting sectors for each of the two pollutants, which for 
SO2 include coal-fired EGUs, industrial boilers, oil-fired 
EGUs, and oil-fired area sources including residential, commercial, and 
industrial sources. Major-emitting sources of NOX include 
on-road vehicles, non-road vehicles, and EGUs.\90\ The RPO's 
documentation explains that ``[EGUs] emitting SO2 and 
NOX and industrial point sources emitting SO2 
were found to be sectors with high emissions that warranted further 
scrutiny. Mobile sources were not considered in this analysis because 
any ask concerning mobile sources would be made to EPA and not during 
the intra-RPO and inter-RPO consultation process among the states and 
tribes.'' \91\ EPA proposes to find that Maryland reasonably evaluated 
the two pollutants--SO2 and NOX--that currently 
drive visibility impairment within the MANE-VU region and that it 
adequately explained and supported its decision to focus on these two

[[Page 58194]]

pollutants through its reliance on the MANE-VU technical analyses cited 
in its submission.
---------------------------------------------------------------------------

    \90\ See Appendix 3 ``MANE-VU Updated Q/d*C Contribution 
Assessment (MANE-VU, April 2016).
    \91\ See docket documents, ``MANE-VU Inter-Regional Ask Final 8-
25-2017 (August 25, 2017)'' and MANE-VU Intra-Regional Ask Final 8-
25-2017 (August 25, 2017).
---------------------------------------------------------------------------

    Section 51.308(f)(2)(i) requires 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. As explained previously, the MANE-VU Asks are a mix of 
measures for sectors and groups of sources identified as reasonable for 
states to address in their regional haze plans. While MANE-VU 
formulated the Asks to be ``reasonable emission reduction strategies'' 
to control emissions of visibility impairing pollutants,\92\ EPA 
believes that Maryland's responses to two of the Asks, in particular, 
engage with the requirement that states determine the emission 
reduction measures that are necessary to make reasonable progress 
through consideration of the four factors. As laid out in further 
detail below, the EPA is proposing to find that MANE-VU's four-factor 
analysis conducted to support the emission reduction measures in Ask 3 
(ultra-low sulfur fuel oil Ask), in conjunction with Maryland's 
supplemental analysis and explanation of how it has complied with Ask 2 
(perform four-factor analyses for sources with potential for >=3.0 
Mm-1 impacts) satisfy the requirement of 40 CFR 
51.308(f)(2)(i). The emission reduction measures that are necessary to 
make reasonable progress must be included in the long-term strategy, 
i.e., in Maryland's SIP. 40 CFR 51.308(f)(2).
---------------------------------------------------------------------------

    \92\ Id.
---------------------------------------------------------------------------

    Maryland asserted that it satisfies Ask 1 because it has SIP-
approved regulations applicable to EGU boilers that include annual 
emission limits for both NOX\93\ \94\ and 
SO2,\95\ and require the most effective use of emission 
control technologies on a year-round basis. Maryland also claimed 
additional SIP-approved SO2 emission reductions as a result 
of the consent order for the Anne Arundel County and Baltimore County 
SO2 nonattainment area for the 2010 SO2 
NAAQS.\96\ As a reminder, MANE-VU Ask 1 requests 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''.\97\ Therefore, EPA 
finds it reasonable to conclude that Maryland has satisfied Ask 1.
---------------------------------------------------------------------------

    \93\ See COMAR 26.11.27, ``Emission Limitations for Power 
Plants'', also at www.epa.gov/sips-md/maryland-sip-emission-limitations-power-plants.
    \94\ See COMAR 26.11.40, ``NOX Ozone Season Emission 
Caps for Non-trading Large NOX Units'' also at 
www.epa.gov/sips-md/maryland-sip-nox-ozone-season-emission-caps-non-trading-large-nox-units.
    \95\ See COMAR 26.11.27, ``Emission Limitations for Power 
Plants'', also at www.epa.gov/sips-md/maryland-sip-emission-limitations-power-plants.
    \96\ See 87 FR 66086, November 2, 2022, and docket documents 
``MDE SO2 2010 NAAQS SIP for Baltimore and Anne Arundel 
NA (January 31, 2020)'', and ``MDE SO2 2010 NAAQS SIP for 
Baltimore and Anne Arundel NA (January 31, 2020)--Appendix B--
Consent Orders, Permits, and Plan Approvals''.
    \97\ See Appendix 7, ``MANE-VU Regional Haze Consultation Report 
(July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    Ask 2 addresses the sources MANE-VU determined have the potential 
for larger than, or equal to, 3.0 Mm-1 visibility impact at 
any MANE-VU Class I area; the Ask requests MANE-VU states to conduct 
four-factor analyses for the specified sources within their borders. 
This Ask explicitly engages with the statutory and regulatory 
requirement to determine reasonable progress based on the four factors; 
MANE-VU considered it ``reasonable to have the greatest contributors to 
visibility impairment conduct a four-factor analysis that would 
determine whether emission control measures should be pursued and what 
would be reasonable for each source.'' \98\
---------------------------------------------------------------------------

    \98\ See Appendix 7, ``MANE-VU Regional Haze Consultation Report 
(July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    As an initial matter, EPA does not necessarily agree that 3.0 
Mm-1 visibility impact is a reasonable threshold for source 
selection. The RHR recognizes that, due to the nature of regional haze 
visibility impairment, numerous and sometimes relatively small sources 
may need to be selected and evaluated for control measures in order to 
make reasonable progress. See 2021 Clarifications Memo at 4.\99\ As 
explained in the 2021 Clarifications Memo, while states have discretion 
to choose any source selection threshold that is reasonable, ``[a] 
state that relies on a visibility (or proxy for visibility impact) 
threshold to select sources for four-factor analysis should set the 
threshold at a level that captures a meaningful portion of the state's 
total contribution to visibility impairment to Class I areas.'' 2021 
Memo at 3.\100\ In this case, the 3.0 Mm-1 threshold 
identified only two sources in Maryland (and only 22 across the entire 
MANE-VU region), indicating that they may be unreasonably high. 
Maryland selected all sources identified by MANE-VU as being above 
MANE-VU's 3.0 Mm-1 threshold for four-factor analysis.
---------------------------------------------------------------------------

    \99\ See docket document, ``EPA 2021 Regional Haze 
Clarifications Memo (July 8, 2021)''.
    \100\ Id.
---------------------------------------------------------------------------

    MANE-VU identified one unit at the Herbert A. Wagner Generating 
Facility,\101\ a coal-fired EGU, and two units at Verso Luke Paper 
Company,\102\ a large industrial source, as having a greater than 3.0 
Mm-1 visibility impact and thus meeting the threshold for 
four-factor analyses. Maryland's SIP submittal indicates that it sent a 
letter requesting a four-factor analysis to Herbert A. Wagner 
Facility's owner/operator,\103\ who subsequently announced that it 
would eliminate the use of coal at the facility. This was codified into 
a consent order between Maryland and the owner/operator to cease coal 
combustion at the facility by January 1, 2026.\104\ Maryland has 
requested that the entire consent order be incorporated into Maryland's 
SIP and made federally enforceable upon EPA's approval; \105\ EPA 
intends to incorporate this consent order into the Maryland SIP by 
reference as a source-specific requirement upon final approval of this 
proposed rulemaking. Maryland's subsequent four-factor analysis for the 
facility concluded that no further control was necessary. Regarding the 
Verso Luke Paper industrial source, Maryland stated that this facility 
ceased operations, shut down and surrendered their existing air permits 
as of May 7, 2020.\106\ Informed in part by this development, EPA found 
that the area was monitoring air quality consistent with achieving the 
2010 1-Hour SO2 Primary NAAQS. See 87 FR 66086, November 2, 
2022. Maryland therefore concluded that no further action was necessary 
for this facility. Given that no other sources in Maryland met the 3.0 
Mm-1 threshold for visibility impacts in MANE-VU's 
analysis,\107\ Maryland concluded that it had met the requirements for 
Ask 2.
---------------------------------------------------------------------------

    \101\ H.A. Wagner Unit 3.
    \102\ Luke Paper Unit 001-0011-3-0018 & Unit 001-0011-3-0019.
    \103\ Raven Power Fort Smallwood, LLC.
    \104\ See Appendix 19, ``Herbert A. Wagner Generating Station 
Consent Order''.
    \105\ See Section 2.5.2 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
    \106\ See docket documents, ``Verso Luke Paper--Luke MD Title V 
Permit Termination (May 7, 2020)'' and ``Verso Luke Paper--Verso 
Luke Close Out Letter (May 8, 2020)''.
    \107\ See Appendix 4, ``2016 MANE VU Source Contribution 
Modeling Report: CALPUFF Modeling of Large Electrical Generating 
Units and Industrial Sources (April 4, 2017)''.
---------------------------------------------------------------------------

    The EPA proposes to find that Maryland reasonably determined it has 
satisfied Ask 2. As explained above, we

[[Page 58195]]

do not necessarily agree that a 3.0 Mm-1 threshold for 
selecting sources for four-factor analysis results in a set of sources 
the evaluation of which has the potential to meaningfully reduce the 
state's contribution to visibility impairment. MANE-VU's threshold 
identified only two sources in Maryland for four-factor analysis. 
However, in this instance we propose to find that Maryland's additional 
information and explanation indicates that the state has in fact 
examined a reasonable set of sources; Maryland chose to address 12 of 
the 13 sources identified by FLMs, including 10 that went beyond the 
MANE-VU source selection process, and reasonably concluded that four-
factor analyses for its top-impacting sources are not necessary because 
the outcome would be that no further emission reductions would be 
reasonable. EPA is basing this proposed finding on the state's 
examination of its largest operating EGU and ICI sources, at the time 
of SIP submission, and on the emissions from and controls that apply to 
those sources, as well as on Maryland's existing SIP-approved 
NOX and SO2 rules that effectively control 
emissions from the largest contributing stationary-source sectors. 
Maryland's submittal includes additional information on and analysis of 
13 Maryland facilities, which was provided in response a National Park 
Service (NPS) analysis that identified these facilities as contributing 
to ``80% of the Q/d total'' visibility impact at downwind NPS Class I 
Federal areas based on 2014 emissions data and requested that states 
``review and consider these sources for inclusion in their long term 
strategies''.\108\ \109\ Maryland provided the NPS with additional 
information on these 13 facilities, including facility descriptions, 
current control devices/technologies for NOX, 
SO2, and PM, current monitoring devices, regulations/consent 
orders/permit conditions that limit emissions, and analysis and 
documentation of historical emissions to demonstrate control strategy 
effectiveness.
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    \108\ See Section 2.6.1 and Table 2-12 of the MD Regional Haze 
SIP for the Second Implementation Period 2018-2028 (February 8, 
2022).
    \109\ See docket document, ``NPS Letter--MANE-VU draft Statement 
on source screening (April 12, 2018)''.
---------------------------------------------------------------------------

    Maryland also examined the 13 facilities identified by NPS as a 
percent of their total Q/d contribution. This included Luke Paper 
Company, which comprised 54.71% of the Q/d total; Maryland stated that 
this facility ceased operations, shut down and surrendered their 
existing air permits as of May 7, 2020.\110\ When combined with Brandon 
Shores Generating Station, H.A. Wagner Generating Station, Chalk Point 
Generating Station, C.P. Crane Generating Station, and Naval Support 
Facility Indian Head, all of which have closed, will close by 2026, or 
have switched or will switch fuels, and Morgantown Generating Station, 
which is considered by Maryland as effectively controlled through SCR, 
these facilities comprised 75.57% of the Q/d total. When adding the two 
municipal solid waste combustor facilities identified by the NPS 
(Wheelabrator and Montgomery County RRF) both of which are considered 
by Maryland as well-controlled, these facilities comprise 82.22% of the 
Q/d total. Finally, Maryland also provided additional information on 
the remaining three sources identified by the NPS (Holcim Cement, 
Lehigh Cement, and the AES Warrior Run EGU).\111\ Therefore, EPA finds 
it reasonable to conclude that Maryland has satisfied Ask 2.
---------------------------------------------------------------------------

    \110\ See docket documents, ``Verso Luke Paper--Luke MD Title V 
Permit Termination (May 7, 2020)'' and ``Verso Luke Paper--Verso 
Luke Close Out Letter (May 8, 2020)''.
    \111\ See Section 2.6.1 and Table 2-13 of the MD Regional Haze 
SIP for the Second Implementation Period 2018-2028 (February 8, 
2022).
---------------------------------------------------------------------------

    Ask 3, which addresses the sulfur content of heating oil used in 
MANE-VU states, is based on a four-factor analysis for the heating oil 
sulfur reduction regulations contained in that Ask; \112\ specifically, 
for the control strategy of reducing the sulfur content of distillate 
oil to 15 ppm. The analysis started with an assessment of the costs of 
retrofitting refineries to produce 15 ppm heating oil in sufficient 
quantities to support implementation of the standard, as well as the 
impacts of requiring a reduction in sulfur content on consumer prices. 
The analysis noted that, as a result of previous EPA rulemakings to 
reduce the sulfur content of on-road and non-road-fuels to 15 ppm, 
technologies are currently available to achieve sulfur reductions and 
many refiners are already meeting this standard, meaning that the 
capital investments for further reductions in the sulfur content of 
heating oil are expected to be relatively low compared to costs 
incurred in the past. The analysis also examined, by way of example, 
the impacts of New York's existing 15 ppm sulfur requirements on 
heating oil prices and concluded that the cost associated with reducing 
sulfur was relatively small in terms of the absolute price of heating 
oil compared to the magnitude of volatility in crude oil prices. It 
also noted that the slight price premium is compensated by cost savings 
due to the benefits of lower-sulfur fuels in terms of equipment life 
and maintenance and fuel stability. Consideration of the time necessary 
for compliance with a 15 ppm sulfur standard was accomplished through a 
discussion of the amount of time refiners had needed to comply with the 
EPA's on-road and non-road fuel 15 ppm requirement, and the 
implications existing refinery capacity and distribution infrastructure 
may have for compliance times with a 15 ppm heating oil standard. The 
analysis concluded that with phased-in timing for states that have not 
yet adopted a 15 ppm heating oil standard there ``appears to be 
sufficient time to allow refiners to add any additional heating oil 
capacity that may be required.'' \113\ The analysis further noted the 
beneficial energy and non-air quality environmental impacts of a 15 ppm 
sulfur heating oil requirement and that reducing sulfur content may 
also have a salutary impact on the remaining useful life of residential 
furnaces and boilers.\114\
---------------------------------------------------------------------------

    \112\ See docket document, ``2016 Updates to the Assessment of 
Reasonable Progress for Regional Haze in MANE-VU Class I Areas 
(January 31, 2016)'' at 8-4.
    \113\ Id. see 8-7.
    \114\ Id. see 8-8.
---------------------------------------------------------------------------

    EPA proposes to find that Maryland reasonably relied on MANE-VU's 
four-factor analysis for a low-sulfur fuel oil regulation, which 
engaged with each of the statutory factors and explained how the 
information supported a conclusion that a 15 ppm sulfur fuel oil 
standard is reasonable; as a reminder, MANE-VU Ask 3 requests that, for 
``each MANE-VU state that has not yet fully adopted an ultra-low fuel 
oil standard as requested by MANE-VU in 2007'', to ``pursue this 
standard as expeditiously as possible and before 2028, depending on 
supply availability''. Maryland's ultra-low sulfur fuel oil regulations 
\115\ are consistent with Ask 3. EPA therefore proposes to find that 
Maryland reasonably determined that it has satisfied Ask 3.
---------------------------------------------------------------------------

    \115\ See COMAR 03.03.05.04, ``Specifications for No. 1 and No. 
2 Fuel Oil (ASTM D-396)''.
---------------------------------------------------------------------------

    Maryland concluded that no additional updates were needed to meet 
Ask 4, which requests that MANE-VU states pursue updating permits, 
enforceable agreements, and/or rules to lock-in lower emission rates 
for sources larger than 250 MMBtu per hour that have switched to lower 
emitting fuels. As explained above, Maryland has asserted that EGUs and 
other large point emission sources that have switched operations to 
lower emitting fuels are already locked into the lower emission rates 
for NOX, SO2, and PM by permits,

[[Page 58196]]

enforceable agreements and/or rules. In addition, modified units in 
Maryland are required to amend their permits through the New Source 
Review (NSR) process if they plan to switch back to coal or a fuel that 
will increase emissions. A change in fuel, unless already allowed in 
the permit, would be a modification,\116\ and Maryland's regulations 
require that an application to modify the permit be submitted prior to 
a change in fuel.\117\ As a reminder, MANE-VU Ask 4 requests that 
states ``pursue updating permits, enforceable agreements, and/or rules 
to lock-in lower emission rates for SO2, NOX, and 
PM'' at ``EGUs and other large point emission sources larger than 250 
MMBTU per hour heat input that have switched to lower emitting fuels''. 
Ask 4 also states that ``the permit, enforceable agreement, and/or rule 
can allow for suspension of the lower emission rate during natural gas 
curtailment''. EPA proposes to find that Maryland reasonably determined 
it has satisfied Ask 4. This is because the permitting and regulatory 
requirements outlined above, including the fact that sources that have 
switched fuel are generally required to revise their permits to reflect 
the change, and because the state rules make any proposed reversion 
difficult by requiring permitting and other control analyses, including 
NSR.
---------------------------------------------------------------------------

    \116\ See COMAR 26.11.01.01, defining ``Modify'' or 
``Modification'' to mean ``any physical change in, or change in the 
operation of, a source or installation which causes a change in the 
quantity, nature or characteristics of emissions from the source or 
installation. However, this term excludes routine maintenance and 
routine repair, and increases in the hours of operation or in the 
production rate, unless these increases would be prohibited under 
any permit or approval conditions adopted by the Department.''
    \117\ See COMAR 26.11.02.02., ``General Provisions'', which 
states that ``A permit to construct and an approval from the 
Department is required before construction or modification of a 
source''.
---------------------------------------------------------------------------

    Ask 5 addresses NOX emissions from peaking combustion 
turbines \118\ that have the potential to operate on high electric 
demand days (HEDD).\119\ Maryland conducted a four-factor analysis to 
evaluate potential control options for HEDD units. For one potentially 
technically feasible control option, Selective Catalytic Reduction 
(SCR), Maryland estimated compliance costs as ranging from $6 million 
to $15.7 million per unit.\120\ These cost estimates are similar to 
those found in EPA's Combustion Turbine NOX Control 
Technology Memo published in January 2022.\121\ Due to the relatively 
low level of reported annual NOX emissions from these units 
within the state (i.e., less than 10 tons of NOX emitted per 
unit per year), Maryland concluded that SCR was not an economically 
feasible control option due to the high cost of control. Maryland also 
evaluated the cost of water/steam injection as a potentially 
technically feasible control option, but found that the cost of control 
($87,906.95 per ton of NOX removed) was not economically 
feasible.\122\ As a reminder, MANE-VU Ask 5 requests that MANE-VU 
states, ``where emission rules have not been adopted, control 
NOX emissions for peaking combustion turbines that have the 
potential to operate on high electric demand days'' by either: ``(a) 
Striving to meet NOX emissions standards of no greater than 
22 ppm at 15% O2 for natural gas and 42 ppm at 15% 
O2 for fuel oil but at a minimum meet NOX 
emission standards of no greater than 42 ppm at 15% O2 for 
natural gas and 96 ppm at 15% O2 for fuel oil'', or ``(b) 
Performing a four-factor analysis for reasonable installation of or 
upgrade to emission controls'', or ``(c) Obtaining equivalent emission 
reductions on high electric demand days.'' \123\ Because Maryland 
evaluated multiple technically feasible controls, the high cost of 
controls, and the relatively low level of reported annual 
NOX emissions from peaking combustion turbines with the 
potential to operate on HEDD days, EPA proposes to find that Maryland 
reasonably concluded that it has satisfied Ask 5.
---------------------------------------------------------------------------

    \118\ Peaking combustion turbine is defined for the purpose of 
this Ask as a turbine capable of generating 15 megawatts or more, 
that commenced operation prior to May 1, 2007, is used to generate 
electricity all or part of which is delivered to electric power 
distribution grid for commercial sale and that operated less than or 
equal to an average of 1,752 hours (or 20%) per year during 2014 to 
2016.
    \119\ High electric demand days are days when higher than usual 
electrical demands bring additional generation units online, many of 
which are infrequently operated and may have significantly higher 
emissions rates of the generation fleet.
    \120\ See Section 2.5.5 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
    \121\ See docket document, ``EPA Combustion Turbine 
NOX Control Technology Memo (January 2022)''.
    \122\ See Section 2.5.5 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
    \123\ See Appendix 7, ``MANE-VU Regional Haze Consultation 
Report (July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    Finally, regarding Ask 6, Maryland explains the greenhouse gas 
initiatives and clean energy requirements within the state, including 
promulgation of the state's 2030 Greenhouse Gas Reduction Act (GGRA) 
Plan, RPS, and participation in RGGI. As a reminder, MANE-VU Ask 6, the 
last Ask, requests that ``each State should consider and report in 
their SIP measures or programs to: (a) decrease energy demand through 
the use of energy efficiency, and (b) increase the use within their 
state of Combined Heat and Power (CHP) and other clean Distributed 
Generation technologies including fuel cells, wind, and solar''.\124\ 
The EPA is therefore proposing to find that Maryland has satisfied Ask 
6's request to consider and report in its SIP measures or programs 
related to energy efficiency, cogeneration, and other clean distributed 
generation technologies.
---------------------------------------------------------------------------

    \124\ See Appendix 7, ``MANE-VU Regional Haze Consultation 
Report (July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    In sum, the EPA is proposing to find that--based on Maryland's 
participation in the MANE-VU planning process, how it has addressed 
each of the Asks, its supplemental information and explanation 
regarding NOX sources and emissions, and the EPA's 
additional assessment of Maryland's emissions and point sources--
Maryland has complied with the requirements of 40 CFR 51.308(f)(2)(i). 
Specifically, MANE-VU Asks 2 and 3 engage with the requirement that 
states evaluate and determine the emission reduction measures that are 
necessary to make reasonable progress by considering the four statutory 
factors. EPA is proposing to find Maryland's approach to Ask 2 
reasonable because it demonstrated that the sources with the greatest 
modeled impacts on visibility either have federally-enforceable shut 
downs, have reduced their emissions so significantly that it is clear a 
four-factor analysis would not yield further reasonable emission 
reductions, or are subject to stringent emission control measures. 
Maryland's SIP-approved control measures, emissions inventory \125\ and 
information provided in response to comments \126\ demonstrate that the 
sources of SO2 and NOX within the state that 
would be expected to contribute to visibility impairment have small 
emissions of NOX and SO2, are well controlled, or 
both. Maryland's sulfur in fuel limits sets stringent limits for sulfur 
content and SO2 emissions for non-solid fuels.\127\ 
Therefore, it is reasonable to assume that selecting additional sources 
from MANE-VU's or FLMs' lists for four-factor analysis would not have 
resulted in additional emission

[[Page 58197]]

reduction measures being determined to be necessary to make reasonable 
progress for the second implementation period.
---------------------------------------------------------------------------

    \125\ See Appendix 1, ``Selection of States for MANE-VU Regional 
Haze Consultation (2018)--Final''.
    \126\ See Appendix 20, ``Public Hearing Notices, Comments, and 
Responses--Regional Haze Second Implementation Period Plan (2018-
2028)''.
    \127\ See COMAR 03.03.05.04, ``Specifications for No. 1 and No. 
2 Fuel Oil (ASTM D-396)''.
---------------------------------------------------------------------------

    Additionally, MANE-VU conducted a four-factor analysis to support 
Ask 3, which requests that states pursue ultra-low sulfur fuel oil 
standards to address SO2 emissions. Maryland has done so. 
This also contributes to satisfying the requirements that states 
determine the emission reduction measures that are necessary to make 
reasonable progress by considering the four factors, and that their 
long-term strategies include the enforceable emission limitations, 
compliance schedules, and other measures necessary to make reasonable 
progress. To the extent that MANE-VU and Maryland regard the measures 
in Asks 1 and 4 through 6 as being part of the region's strategy for 
making reasonable progress, we propose to find it reasonable for 
Maryland to address these Asks by pointing to existing measures that 
satisfy each.
3. Additional Long-Term Strategy Requirements
    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 coordinate emission management strategies containing the 
emission reductions measures that are necessary to make reasonable 
progress. Section 51.308(f)(2)(ii)(A) and (B) require states to 
consider the emission reduction measures identified by other states as 
necessary for reasonable progress and to include agreed upon measures 
in their SIPs, respectively. Section 51.308(f)(2)(ii)(C) speaks to what 
happens if states cannot agree on what measures are necessary to make 
reasonable progress.
    Maryland participated in and provided documentation of the MANE-VU 
intra- and inter-RPO consultation processes and addressed the MANE-VU 
Asks by providing information on the measures it has in place that 
satisfy each Ask.128 129 MANE-VU also documented 
disagreements that occurred during consultation. MANE-VU noted in their 
Consultation Report that upwind states expressed concern regarding the 
analyses the RPO utilized for the selection of states for the 
consultation. MANE-VU agreed that these tools, as all models, have 
their limitations, but nonetheless deemed them appropriate. 
Additionally, there were several comments regarding the choice of the 
2011 modeling base year. MANE-VU agreed that the choice of base year is 
critical to the outcome of the study. MANE-VU acknowledged that there 
were newer versions of the emission inventories and the need to use the 
best available inventory for each analysis. However, MANE-VU disagreed 
that the choice of these inventories was not appropriate for the 
analysis. Upwind states also suggested that MANE-VU states adopt the 
2021 timeline for regional haze SIP submissions for the second planning 
period. MANE-VU agreed with the reasons the comments provided, such as 
collaboration with data and planning efforts. However, MANE-VU 
disagreed that the 2018 timeline would prohibit collaboration. 
Additionally, upwind states noted that they would not be able to 
address the MANE-VU Asks until they finalize their SIPs. MANE-VU 
believed the assumption of the implementation of the Asks from upwind 
states in its 2028 control case modeling was reasonable.
---------------------------------------------------------------------------

    \128\ See Appendix 5, ``Inter-RPO Consultation Briefing Book''; 
Appendix 7, ``MANE-VU Regional Haze Consultation Report''; Appendix 
9, ``National Park Service Letter to MANE-VU (April 2018)''; and 
Appendix 17, ``Additional MANE-VU documentation for establishing 3.0 
Mm-1 Threshold''.
    \129\ See Appendix 14, ``FLM Consultation Initiation Letter 
(April 2019)''; Appendix 15, ``National Park Service Correspondence 
with Maryland''; Appendix 16, ``US Forest Service Consultation 
Response Letter''; and Appendix 20, ``Public Hearing Notices, 
Comments, and Responses--Regional Haze Second Implementation Period 
Plan (2018-2028)''.
---------------------------------------------------------------------------

    In sum, Maryland participated in the MANE-VU intra- and inter-RPO 
consultation and satisfied the MANE-VU Asks, satisfying 40 CFR 
51.308(f)(2)(ii)(A) and (B). Maryland satisfied 40 CFR 
51.308(f)(2)(ii)(C) by participating in MANE-VU's consultation process, 
which documented the disagreements between the upwind states and MANE-
VU and explained MANE-VU's reasoning on each of the disputed issues. 
Based on the entirety of MANE-VU's intra- and inter-RPO consultation 
and both MANE-VU's and Maryland's responses to states' comments on the 
SIP submission and various technical analyses therein, we propose to 
determine that Maryland has satisfied the consultation requirements of 
40 CFR 51.308(f)(2)(ii).
    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.'' As 
explained above, Maryland chose to rely on MANE-VU's technical 
information, modeling, and analysis to support development of its long-
term strategy. The MANE-VU technical analyses on which Maryland relied 
are listed in the state's SIP submission and include source 
contribution assessments, information on each of the four factors and 
visibility modeling information for certain EGUs, and evaluations of 
emission reduction strategies for specific source categories. Maryland 
also provided supplemental information to further demonstrate the 
technical bases and emission information on which it relied on to 
determine the emission reductions measures that are necessary to make 
reasonable progress. Based on the documentation provided by the state, 
we propose to find Maryland satisfies the documentation requirements of 
40 CFR 51.308(f)(2)(iii).
    Section 51.308(f)(2)(iii) also requires that the emissions 
information considered to determine the measures that are necessary to 
make reasonable progress include information on emissions for the most 
recent year for which the state has submitted triennial emissions data 
to the EPA (or a more recent year), with a 12-month exemption period 
for newly submitted data. Maryland's SIP submission included 2017 NEI 
emission data for NOX, SO2, PM, and 
NH3 and 2017 Air Markets Program Data (AMPD) emissions for 
NOX and SO2. Maryland's SIP submission also 
included 2019 AMPD for NOX and SO2.\130\ Based on 
Maryland's consideration and analysis of the 2017 and 2019 emission 
data in their SIP submittal and supplemental documentation, the EPA 
proposes to find that Maryland has satisfied the emissions information 
requirement in 40 CFR 51.308(f)(2)(iii).
---------------------------------------------------------------------------

    \130\ See Section 2.21 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    We also propose to find that Maryland reasonably considered the 
five additional factors in 40 CFR 51.308(f)(2)(iv) in developing its 
long-term strategy. Pursuant to 40 CFR 51.308(f)(2)(iv)(A), Maryland 
noted that existing and ongoing state and Federal emission control 
programs that contribute to emission reductions through 2028 would 
impact emissions of visibility impairing pollutants from point and 
nonpoint sources in the second implementation period. Maryland included 
in their SIP comprehensive lists of control measures with their 
effective dates, pollutants addressed, and corresponding Code of 
Maryland Regulations provisions.\131\
---------------------------------------------------------------------------

    \131\ See Section 2.8.1 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).

---------------------------------------------------------------------------

[[Page 58198]]

    Maryland's consideration of measures to mitigate the impacts of 
construction activities as required by 40 CFR 51.308(f)(2)(iv)(B) 
includes, in section 2.8.2 of its SIP submission, a list of measures 
that Maryland has implemented to mitigate the impacts from such 
activities. Maryland has implemented standards that reduce fugitive 
dust emissions from construction,\132\ rules to address exhaust 
emissions,133 134 135 including rules to limit the idling of 
vehicles and equipment and rules to reduce allowable smoke from on-road 
diesel engines,\136\ and general conformity rules.137 138
---------------------------------------------------------------------------

    \132\ COMAR 26.11.06.03. ``Particulate Matter'', subsection D; 
State Effective Date November 11, 2002 (29:22 Md. R. 1724) (68 FR 
46487).
    \133\ COMAR 11.14. ``MOTOR VEHICLE ADMINISTRATION--VEHICLE 
INSPECTIONS'', .01, .06, and .08.
    \134\ COMAR. 11.21.02. ``Diesel Vehicle Emissions Control 
Program''; State Effective Date July 10, 2000 (27:13 Md. R. 1212).
    \135\ Md. Code, Transp. Sec.  23-401 through 23-404.
    \136\ Md. Code, Transp. Sec.  21-1101.
    \137\ The authority to address General Conformity is set forth 
in Section 176(c) of the Clean Air Act and the requirements to 
demonstrate conformity are found in the EPA's implementing 
regulation (40 CFR part 93, subpart B--Determining Conformity of 
General Federal Actions to State or Federal Implementation Plans).
    \138\ COMAR 26.11.26. ``Conformity''; State Effective Date June 
5, 1995 (22:11 Md. R. 825).
---------------------------------------------------------------------------

    Pursuant to 40 CFR 51.308(f)(2)(iv)(C), source retirements and 
replacement schedules are addressed in section 2.8.3 of Maryland's 
submission. Source retirements and replacements were considered in 
developing the 2028 emission projections, with on the books/on the way 
retirements and replacements included in the 2028 projections. The EGU 
point sources included in the inventories used in the MANE-VU 
contribution assessment and that were subsequently retired are 
identified in Table 2-14.\139\ No non-EGU point source retirements in 
Maryland were considered when developing the 2028 emissions 
projections.
---------------------------------------------------------------------------

    \139\ See ``Table 2-14: Units Retired in the Regional Haze 
Inventories'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018--2028 (February 8, 2022).
---------------------------------------------------------------------------

    In considering smoke management as required in 40 CFR 
51.308(f)(2)(iv)(D), Maryland explained, in section 2.8.4 of its 
submission, that emissions from agricultural and prescribed burning for 
forestry smoke management within the state are low; PM2.5 
statewide emissions from prescribed fires were 1,349.18 tons (4.13% of 
Maryland's overall PM2.5 emissions inventory) and emissions 
from agricultural burning were 1.5 tons (<1% of Maryland's overall 
PM2.5 emissions inventory). Maryland therefore concludes 
that it is unlikely that fires in Maryland for agricultural or forestry 
management cause impacts on visibility in the MANE-VU and nearby Class 
I areas, including Shenandoah, Dolly Sods, Otter Creek, and James River 
Face. Maryland states that Smoke Management Plans is a required element 
of a SIP only if it is required to make reasonable progress, and that 
although Maryland does not need an official Smoke Management Plan, it 
has the legal authority to manage burning through a formal permitting 
system if necessary.
    Maryland considered the anticipated net effect of projected changes 
in emissions as required by 40 CFR 51.308(f)(2)(iv)(E) by discussing, 
in section 2.8.5 of its submission, the photochemical modeling for the 
2018-2028 period it conducted in collaboration with MANE-VU. The two 
modeling cases run were a 2028 base case, which considered only on-the-
books controls, and a 2028 control case that considered implementation 
of the MANE-VU Ask. Maryland presented the differences between the base 
and control cases on the 20% most impaired and 20% clearest days for 
each MANE-VU Class I area.\140\
---------------------------------------------------------------------------

    \140\ See Figures 2-7 through 2-10 of the MD Regional Haze SIP 
for the Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    Because Maryland has reasonably considered each of the five 
additional factors the EPA proposes to find that Maryland has satisfied 
the requirements of 40 CFR 51.308(f)(2)(iv).

F. Reasonable Progress Goals

    Section 51.308(f)(3) contains the requirements pertaining to RPGs 
for each Class I area. Section 51.308(f)(3)(i) requires a state in 
which a Class I area is located to establish RPGs--one each for the 
most impaired and clearest days--reflecting the visibility conditions 
that will be achieved at the end of the implementation period as a 
result of the emission limitations, compliance schedules and other 
measures required under paragraph (f)(2) to be in states' long-term 
strategies, as well as implementation of other CAA requirements. The 
long-term strategies as reflected by the RPGs must provide for an 
improvement in visibility on the most impaired days relative to the 
baseline period and ensure no degradation on the clearest days relative 
to the baseline period. Section 51.308(f)(3)(ii) applies in 
circumstances in which a Class I area's RPG for the most impaired days 
represents a slower rate of visibility improvement than the uniform 
rate of progress calculated under 40 CFR 51.308(f)(1)(vi). Under 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. Section 
51.308(f)(3)(ii)(B) requires that if a state contains sources that are 
reasonably anticipated to contribute to visibility impairment in a 
Class I area in another state, and the RPG for the most impaired days 
in that Class I area is above the URP, the upwind state must provide 
the same demonstration. Because Maryland has no Class I areas within 
its borders, it is subject only to 40 CFR 51.308(f)(3)(ii)(B).
    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. 
Maryland's SIP submittal included MANE-VU's glidepath checks for nearby 
downwind Class I areas,141 142 which show that the RPG for 
the 20 percent most anthropogenically impaired days for the affected 
downwind Class I areas (Acadia, Brigantine, Great Gulf, Lye Brook, 
Moosehorn, Dolly Sods and Shenandoah) are not above the URP glidepath, 
and that the RPG for the 20 percent clearest days shows no degradation. 
In addition, the modeled MANE-VU 2028 visibility projections at nearby 
Class I areas \143\ show that the base case 2028 projections for the 
most impaired days at these areas are below the respective 2028 points 
on the URPs. Therefore, we propose 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.
---------------------------------------------------------------------------

    \141\ See docket document, ``TD MANE-VU 2000-19 RH METRICS 
COMPARISON PLOTS 12-19-20.xlsx''.
    \142\ See docket document, ``TD MANE-VU 2000-19 RHII & III 
Metrics Trends Plots 12-19-20.xlsx''.
    \143\ See docket document, ``MANE-VU Trends 2004-17 Report 2nd 
SIP Metrics--December 2018 Update--Final''.
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    The EPA proposes to determine that Maryland has satisfied the 
applicable requirements of 40 CFR 51.308(f)(3) relating to RPGs.

[[Page 58199]]

G. Monitoring Strategy and Other Implementation Plan Requirements

    Section 51.308(f)(6) specifies that each comprehensive revision of 
a state's regional haze SIP must contain or provide for certain 
elements, including monitoring strategies, emissions inventories, and 
any reporting, recordkeeping and other measures needed to assess and 
report on visibility. A main requirement of this subsection is for 
states with Class I areas to submit monitoring strategies for 
measuring, characterizing, and reporting on visibility impairment. 
Compliance with this requirement may be met through participation in 
the Interagency Monitoring of Protected Visual Environments (IMPROVE) 
network.
    Section 51.308(f)(6)(i) requires SIPs to provide for the 
establishment of any additional monitoring sites or equipment needed to 
assess whether reasonable progress goals to address regional haze for 
all mandatory Class I Federal areas within the state are being 
achieved. Section 51.308(f)(6)(ii) requires SIPs to provide for 
procedures by which monitoring data and other information are used in 
determining the contribution of emissions from within the state to 
regional haze visibility impairment at mandatory Class I Federal areas 
both within and outside the state. Because Maryland does not have any 
Class I Federal areas located within its borders, Section 
51.308(f)(6)(i) and (ii) do not apply.
    Section 51.308(f)(6)(iii) requires 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. 
Maryland stated that, as a participant in MANE-VU, it reviewed 
information about the chemical composition of baseline monitoring data 
at Class I Federal areas in and near MANE-VU in order to understand the 
sources of haze causing pollutants. Maryland commits to continuing 
support of ongoing visibility monitoring in Class I Federal areas, 
agrees that the IMPROVE network is an appropriate monitoring network to 
track regional haze progress, and commits to working with neighboring 
states and FLMs to meet the goals of the IMPROVE program. Maryland also 
commits to using monitoring data and procedures consistent with US EPA 
guidance to review progress and trends in visibility at Class I Federal 
areas that may be affected by emissions from Maryland, both for 
comprehensive periodic revisions of this implementation plan and for 
periodic reports describing progress towards the reasonable progress 
goals for those areas.\144\
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    \144\ See Section 2.16 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    Section 51.308(f)(6)(iv) requires 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, 
Maryland does not have any Class I Federal areas located within its 
borders, therefore this requirement does not apply.
    Section 51.308(f)(6)(v) requires 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 and estimates of 
future projected emissions. It also requires a commitment to update the 
inventory periodically. Maryland provides for emissions inventories and 
estimates for future projected emissions by participating in the MANE-
VU RPO and complying with EPA's Air Emissions Reporting Rule (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 (EIS) 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.
    Section 2.21 of Maryland's submission includes tables of NEI data. 
The source categories of the emissions inventories included are: (1) 
point sources, (2) nonpoint sources, (3) non-road mobile sources, and 
(4) on-road mobile sources. The point source category is further 
divided into AMPD point sources and non-AMPD point sources.\145\ 
Maryland included NEI emissions inventories for the following years: 
2002 (one of the regional haze program baseline years), 2008, 2011, 
2014, and 2017; and for the following pollutants: SO2, 
NOX, PM10, PM2.5, VOCs, and 
NH3. Maryland also provided a summary of SO2 and 
NOX emissions for AMPD sources for the years of 2016, 2017, 
2018, and 2019.
---------------------------------------------------------------------------

    \145\ AMPD sources are facilities that participate in EPA's 
emission trading programs. The majority of AMPD sources are electric 
generating units (EGUs).
---------------------------------------------------------------------------

    Section 51.308(f)(6)(v) also requires states to include estimates 
of future projected emissions and include a commitment to update the 
inventory periodically. Maryland relied on the MANE-VU 2028 emissions 
projections for MANE-VU states. MANE-VU completed two 2028 projected 
emissions modeling cases--a 2028 base case that considers only on-the-
books controls and a 2028 control case that considers implementation of 
the MANE-VU Asks.\146\
---------------------------------------------------------------------------

    \146\ See Appendix 11 ``Ozone Transport Commission/Mid-Atlantic 
Northeastern Visibility Union 2011 Based Modeling Platform Support 
Document--October 2018 Update (October 2018)''.
---------------------------------------------------------------------------

    EPA proposes to find that Maryland has met the requirements of 40 
CFR 51.308(f)(6) as described above, including through its continued 
participation in the IMPROVE network and the MANE-VU RPO and its on-
going compliance with the AERR, and that no further elements are 
necessary at this time for Maryland to assess and report on visibility 
pursuant to 40 CFR 51.308(f)(6)(vi).

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

    Section 51.308(f)(5) requires 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. Section 
51.308(g)(1) and (2) apply to all states 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. 
Section 51.308(g)(3) applies 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. Section 51.308(g)(4) applies 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

[[Page 58200]]

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.
    Maryland's submission describes the status of measures of the long-
term strategy from the first implementation period. As a member of 
MANE-VU, Maryland considered the MANE-VU Asks and adopted corresponding 
measures into its long-term strategy for the first implementation 
period. The MANE-VU Asks were: (1) Timely implementation of Best 
Available Retrofit Technology (BART) requirements; (2) EGU controls 
including Controls at 167 Key Sources that most affect MANE-VU Class I 
areas; (3) Low sulfur fuel oil strategy; and (4) Continued evaluation 
of other control measures. Maryland met all the identified reasonable 
measures requested during the first implementation period. During the 
first planning period for regional haze, programs that were put in 
place focused on reducing sulfur dioxide (SO2) emissions. 
The reductions achieved led to vast improvements in visibility at the 
MANE-VU Federal Class I Areas due to reduced sulfates formed from 
SO2 emissions. Maryland describes in Section 2.18 of its 
submittal control measures put in place during the first implementation 
period to help reduce the emissions of visibility-impairing pollutants, 
including NOX and SO2. This includes the Maryland 
Healthy Air Act (HAA), which covered Maryland emission sources named in 
MANE-VU's ``167 Stacks''; the HAA was implemented in 2010 and further 
tightened SO2 emission control requirements in 2013, 
resulting in significant reductions in visibility-impairing pollutants 
throughout the state that exceeded MANE-VU target goals. Maryland also 
described its implementation of low sulfur fuel oil standards for the 
state, and the status of the remaining emissions sources in the state 
subject to BART requirements, which included emission reductions for 
Portland cement plants to satisfy Reasonably Available Control 
Technology (RACT) requirements for ozone.\147\
---------------------------------------------------------------------------

    \147\ COMAR 26.11.30--Control of Portland Cement Manufacturing 
Plants. Effective date: July 20, 2015 (42:Md. R. 884). 
www.dsd.state.md.us/comar/SubtitleSearch.aspx?search=26.11.30.* 
Approved by EPA March 28, 2018, 83 FR 13192
---------------------------------------------------------------------------

    EPA proposes to find that Maryland 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.
    Section 51.308(g)(3) requires states to assess Reasonable Progress 
Goals, including current visibility conditions and changes, for any 
Class I areas within the state. As described above, Maryland does not 
have any Class I areas within its borders, therefore 40 CFR 
51.308(g)(3) does not apply.
    Pursuant to 40 CFR 51.308(g)(4), in Section 2.21 of their 
submittal, Maryland provided a summary of emissions of NOX, 
SO2, PM10, PM2.5, VOCs, and 
NH3 from all sources and activities, including from point, 
nonpoint, non-road mobile, and on-road mobile sources, for the time 
period from 2002 to 2017. Maryland also included AMPD data for 
SO2 and NOX emissions for 2016, 2017, 2018, and 
2019 in their submission.
    The reductions achieved through Maryland emission control measures 
are seen in the emissions inventory. Based on Maryland's SIP submittal, 
NOX emissions have continuously declined in Maryland from 
2002 through 2017, especially in the point, nonroad and onroad mobile 
sectors. During that period, onroad sources contributed almost half of 
the emissions at 47%, followed by point sources at 27%. Nonroad sources 
contributed 13% and area sources contributed 13%. Table 2-20 of 
Maryland's SIP submittal also shows additional NOX emissions 
data from 2016 to 2019 for Maryland's point sources that report to 
EPA's AMPD. NOX emissions are expected to continue to 
decrease as fleet turnover occurs and the older more polluting vehicles 
and equipment are replaced by newer, cleaner ones.\148\
---------------------------------------------------------------------------

    \148\ See Section 2.21.1 and Table 2-20 of the MD Regional Haze 
SIP for the Second Implementation Period 2018--2028 (February 8, 
2022)
---------------------------------------------------------------------------

    Emissions of SO2 have shown a significant decline in 
Maryland from 2002 to 2017 across multiple sectors; see Section 2.21.3 
and Table 2-28 of Maryland's SIP submittal.\149\ Reductions in point 
emissions are primarily due to the acid rain program, Maryland power 
plant consent decrees and regulations including the Maryland Health Air 
Act, and Federal and State low sulfur fuel regulations. Additionally, 
some of these decreases may be attributable to the MANE-VU low sulfur 
fuel strategy and the 90% or greater reduction in SO2 
emissions at 167 EGU stacks, both inside and outside of MANE-VU, 
requested in the ``Non-MANE-VU Ask'' for states within MANE-VU for the 
first regional haze planning period.\150\
---------------------------------------------------------------------------

    \149\ See Section 2.21.3 and Table 2-28 of the MD Regional Haze 
SIP for the Second Implementation Period 2018-2028 (February 8, 
2022).
    \150\ See ``Statement of the Mid-Atlantic/Northeast Visibility 
Union (MANE-VU) Concerning a Course of Action within MANE-VU Toward 
Assuring Reasonable Progress'' in the docket.
---------------------------------------------------------------------------

    Emissions of PM10 have steadily decreased in Maryland 
from 2002 to 2017, particularly in the point and nonroad sectors; see 
Section 2.21.2 and Table 2-25 of Maryland's SIP submittal.\151\ The 
variations in the onroad sector are likely due to changes in emission 
inventory calculation methodologies, which resulted in higher 
particulate matter estimates in the other years than in 2002. The large 
variation in emissions in the nonpoint category is likely due to 
changes in calculation methodologies for residential wood burning and 
fugitive dust categories, which have varied significantly.
---------------------------------------------------------------------------

    \151\ See Section 2.21.2 and Table 2-25 of the MD Regional Haze 
SIP for the Second Implementation Period 2018-2028 (February 8, 
2022).
---------------------------------------------------------------------------

    Emissions of ammonia (NH3) have shown declines in 
Maryland from 2002 to 2017; see Section 2.21.4 and Table 2-33 of 
Maryland's SIP submittal.\152\ Ammonia decreases were achieved in the 
onroad sector due to Federal new engine standards for vehicles and 
equipment. Nonpoint increases and decreases from 2002 to 2014 are due 
to reporting, grouping and methodology changes. While ammonia emissions 
grew slightly between the 2002 and 2008 emission inventories, ammonia 
emissions have decreased from 2011 to 2017.
---------------------------------------------------------------------------

    \152\ See Section 2.21.4 and Table 2-33 of the MD Regional Haze 
SIP for the Second Implementation Period 2018-2028 (February 8, 
2022).
---------------------------------------------------------------------------

    The EPA is proposing to find that Maryland has satisfied the 
requirements of 40 CFR 51.308(g)(4) by providing emissions information 
for NOX, SO2, PM10, PM2.5, 
VOCs, and NH3 broken down by type of source.
    Maryland uses the emissions trend data in the SIP submission \153\ 
and supporting MANE-VU information \154\ provided to support the 
assessment that

[[Page 58201]]

anthropogenic haze-causing pollutant emissions in Maryland have 
decreased during the reporting period and that changes in emissions 
have not limited or impeded progress in reducing pollutant emissions 
and improving visibility, Maryland 2017 emission inventories for 
NOX, SO2, PM10, PM2.5, 
VOCs, and NH3 were lower than their 2014 emission 
inventories for those same pollutants emissions.\155\ The EPA is 
proposing to find that Maryland has met the requirements of 40 CFR 
51.308(g)(5).
---------------------------------------------------------------------------

    \153\ See Section 2.21 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
    \154\ See docket document, ``MANE-VU Trends 2004-17 Report 2nd 
SIP Metrics - December 2018 Update--Final''.
    \155\ See Section 2.16 of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

I. Requirements for State and Federal Land Manager Coordination

    Section 169A(d) of the Clean Air Act 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 sixty days before a public hearing or public 
comment period at the state level. Section 51.308(i)(2) also provides 
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. Section 51.308(i)(3) 
requires states, in developing their implementation plans, to include a 
description of how they addressed FLMs' comments.
    The states in the MANE-VU RPO conducted FLM consultation early in 
the planning process concurrent with the state-to-state consultation 
that formed the basis of the RPO's decision making process. As part of 
the consultation, the FLMs were given the opportunity to review and 
comment on the technical documents developed by MANE-VU. The FLMs were 
invited to attend the intra- and inter-RPO consultations calls among 
states and at least one FLM representative was documented to have 
attended seven intra-RPO meetings and all inter-RPO meetings. Maryland 
participated in these consultation meetings and calls.\156\
---------------------------------------------------------------------------

    \156\ See Appendix 7, ``MANE-VU Regional Haze Consultation 
Report (July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
---------------------------------------------------------------------------

    As part of this early engagement with the FLMs, on April 12, 2018, 
the NPS sent letters to the MANE-VU states requesting that they 
consider specific individual sources in their long-term 
strategies.\157\ NPS used an analysis of emissions divided by distance 
(Q/d) to estimate the impact of MANE-VU facilities. To select the 
facilities, NPS first summed 2014 NEI NOX, PM10, 
SO2, and SO4 emissions and divided by the 
distance to a specified NPS mandatory Class I Federal area. NPS summed 
the Q/d values across all MANE-VU states relative to Acadia, Mammoth 
Cave and Shenandoah National Parks, ranked the Q/d values relative to 
each Class I area, created a running total, and identified those 
facilities contributing to 80% of the total impact at each NPS Class I 
area. NPS applied a similar process to facilities in Maine relative to 
Acadia National Park. NPS merged the resulting lists of facilities and 
sorted them by their states. NPS suggested that a state consider those 
facilities comprising 80% of the Q/d total, not to exceed the 25 top 
ranked facilities. The NPS identified 12 facilities in Maryland in this 
letter.\158\ Maryland included the NPS initial letter in their proposed 
SIP. In a subsequent letter dated October 22, 2018, NPS identified 13 
facilities for which more control information was desired.\159\ 
Maryland detailed the emission controls and updates to these facilities 
in its SIP submittal to address the NPS's request for more 
information.\160\
---------------------------------------------------------------------------

    \157\ See Appendix 7, ``MANE-VU Regional Haze Consultation 
Report (July 27, 2018),'' and Appendix 9, ``National Park Service 
Letter to MANE-VU (April 2018)'' of the MD Regional Haze SIP for the 
Second Implementation Period 2018-2028 (February 8, 2022).
    \158\ See Appendix 7, ``MANE-VU Regional Haze Consultation 
Report (July 27, 2018),'' of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
    \159\ See Appendix 15, ``National Park Service Correspondence 
with Maryland'', of the MD Regional Haze SIP for the Second 
Implementation Period 2018-2028 (February 8, 2022).
    \160\ See Section 2.6 and Appendix 20 of the MD Regional Haze 
SIP for the Second Implementation Period 2018-2028 (February 8, 
2022).
---------------------------------------------------------------------------

    On September 2, 2021, Maryland submitted a draft Regional Haze SIP 
to the U.S. Forest Service, the U.S. Fish and Wildlife Service, and the 
National Park Service for a 60-day review and comment period pursuant 
to 40 CFR 51.308(i)(2).\161\ Maryland received comments from the Forest 
Service on October 28, 2021, and from the National Park Service on 
October 29, 2021. Maryland responded to the FLM comments and included 
the responses in Appendix 20 of their submission to EPA, in accordance 
with 40 CFR 51.308(i)(3). Notices of the proposed SIP, availability and 
the public hearing were published on MDE's website and in the Maryland 
Register, and interested parties were emailed the notice, along with 
air quality contacts from other states, air quality regional 
organizations and the EPA. A public hearing on the proposed SIP 
revision was held on January 4, 2022. Written comments relevant to the 
proposal were accepted until the close of business January 4, 2022.
---------------------------------------------------------------------------

    \161\ See Appendix 14, Appendix 15, Appendix 16, and Appendix 20 
of the MD Regional Haze SIP for the Second Implementation Period 
2018-2028 (February 8, 2022), and docket documents, ``National Park 
Service Comments''; ``State of Maryland Mail--Forest Service''; 
``USFS MD RH SIP Comment Letter''; ``USFS MD RH SIP Comment 
Enclosure''
---------------------------------------------------------------------------

    For the reasons stated above, the EPA proposes to find that 
Maryland has satisfied the requirements under 40 CFR 51.308(i) to 
consult with the FLMs on its regional haze SIP for the second 
implementation period.
    Maryland's February 8, 2022 SIP submission includes a commitment to 
revise and submit a regional haze SIP by July 31, 2028, and every ten 
years thereafter. The state's commitment includes submitting periodic 
progress reports in accordance with 40 CFR 51.308(f) and a commitment 
to evaluate progress towards the reasonable progress goal for 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 in accordance with 40 CFR 
51.308(g).\162\
---------------------------------------------------------------------------

    \162\ See Section 2.17, ``Progress Report Requirements'', of the 
MD Regional Haze SIP for the Second Implementation Period 2018-2028 
(February 8, 2022).
---------------------------------------------------------------------------

V. Proposed Action

    EPA is proposing to approve Maryland's February 8, 2022 SIP 
submission, 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

[[Page 58202]]

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 13563 (76 FR 3821, January 21, 
2011);
     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 an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001);
     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; and
    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 minority populations and low-income 
populations to the greatest extent practicable and permitted by law. 
EPA defines environmental justice (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.'' The Maryland 
Department of the Environment did not evaluate environmental justice 
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 people of color, low-income populations, and 
Indigenous peoples.
    In addition, this proposed rulemaking action, pertaining to 
Maryland regional haze SIP submission for the second planning period, 
is not approved to apply on any Indian reservation land or in any other 
area where the 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).

List of Subjects in 40 CFR Part 52

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

Adam Ortiz,
Regional Administrator, Region III.
[FR Doc. 2023-18278 Filed 8-24-23; 8:45 am]
BILLING CODE 6560-50-P


