[Federal Register Volume 90, Number 116 (Wednesday, June 18, 2025)]
[Proposed Rules]
[Pages 25975-25984]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-11257]


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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R05-OAR-2021-0577; FRL-12588-01-R5]


Air Plan Approval; Michigan; Second Period Regional Haze Plan

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 Michigan Department of Environment, Great Lakes, and 
Energy (EGLE) on August 23, 2021, and supplemented on April 3, 2025, as 
satisfying applicable requirements under the Clean Air Act (CAA) and 
EPA's Regional Haze Rule (RHR) for the program's second implementation 
period. EGLE'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. EPA is taking this 
action pursuant to sections 110 and 169A of the CAA.

DATES: Comments must be received on or before July 18, 2025.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2021-0577 at https://www.regulations.gov, or via email to 
[email protected]. For comments submitted at Regulations.gov, 
follow the online instructions for submitting comments. Once submitted, 
comments cannot be edited or removed from the docket. EPA may publish 
any comment received to its public docket. Do not submit to EPA's 
docket at https://www.regulations.gov any information you consider to 
be Confidential Business Information (CBI), Proprietary Business 
Information (PBI), or other information whose disclosure is restricted 
by statute. Multimedia submissions (audio, video, etc.) must be 
accompanied by a written comment. The written comment is considered the 
official comment and should include discussion of all points you wish 
to make. EPA will generally not consider comments or comment contents 
located outside of the primary submission (i.e., on the web, cloud, or 
other file sharing system). For additional submission methods, please 
contact the person identified in the FOR FURTHER INFORMATION CONTACT 
section. For the full EPA public comment policy, information about CBI, 
PBI, or multimedia submissions, and general guidance on making 
effective comments, please visit https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Matt Rau, Air and Radiation Division 
(AR-18J), Environmental Protection Agency, Region 5, 77 West Jackson 
Boulevard, Chicago, Illinois 60604, (312) 886-6524, 
[email protected]. The EPA Region 5 office is open from 8:30 a.m. to 
4:30 p.m., Monday through Friday, excluding Federal holidays.

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

I. What action is EPA proposing?
    A. What is parallel processing?
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. Long-Term Strategy for Regional Haze
    B. Reasonable Progress Goals (RPGs)
    C. Monitoring Strategy and Other SIP Requirements
    D. Requirements for Periodic Reports Describing Progress Towards 
the RPGs
    E. Requirements for State and Federal Land Manager Coordination
IV. EPA's Evaluation of EGLE's Regional Haze Submission for the 
Second Implementation Period
    A. Background on EGLE's First Implementation Period SIP 
Submission
    B. EGLE's Second Implementation Period SIP Submission and EPA's 
Evaluation
    C. Identification of Class I Areas
    D. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress
    E. Long-Term Strategy for Regional Haze
    1. Emission Measures Necessary To Make Reasonable Progress
    2. EPA's Evaluation of EGLE's Compliance With 40 CFR 
51.308(f)(2)(i)
    F. RPGs
    G. Monitoring Strategy and Other Implementation Plan 
Requirements
    H. Requirements for Periodic Reports Describing Progress Towards 
the RPGs
    I. Requirements for State and Federal Land Manager Coordination
V. Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is EPA proposing?

    On August 23, 2021, EGLE submitted a revision to its SIP to address 
regional haze requirements for the second implementation period. On 
April 3, 2025, EGLE submitted a supplement in draft for parallel 
processing. EGLE made this SIP submission to satisfy the requirements 
of the CAA's regional haze program pursuant to CAA sections 169A and 
169B and 40 CFR 51.308. EPA proposes to find that the Michigan Regional 
Haze SIP submission for the second implementation period meets the 
applicable statutory and regulatory requirements. Thus, EPA proposes to 
approve EGLE's submission into its SIP.

A. What is parallel processing?

    Consistent with EPA regulations found at 40 CFR part 51, appendix 
V, section 2.3.1, for purposes of expediting review of a SIP 
submission, parallel processing allows a State to submit a plan to EPA 
prior to final adoption by the State.
    Generally, the State submits a copy of the proposed regulation or 
other revisions to EPA before conducting its public hearing. EPA 
reviews this proposed State action and prepares a notice of proposed 
rulemaking. EPA's notice of proposed rulemaking is published in the 
Federal Register during the same time frame that the

[[Page 25976]]

State is holding its public process. The State and EPA then provide for 
concurrent public comment periods on both the State action and Federal 
action.
    If the revision that is finally adopted and submitted by EGLE is 
changed in aspects other than those identified in the proposed 
rulemaking on the parallel process submission, EPA will evaluate those 
changes and if necessary and appropriate, issue another notice of 
proposed rulemaking. The final rulemaking action by EPA will occur only 
after the SIP revision has been adopted by the State and submitted 
formally to EPA for incorporation into the SIP.
    On April 3, 2025, EGLE submitted a request for parallel processing 
of a draft SIP supplement that it has taken to public comment on March 
10, 2025. EGLE requested parallel processing so that EPA can act on its 
Regional Haze SIP revision in advance of EGLE's submission of a SIP 
supplement. As stated previously, the final rulemaking action by EPA 
will occur only after the SIP supplement has been: (1) submitted 
formally to EPA for incorporation into the SIP and (2) evaluated by 
EPA, including any changes made by EGLE after the April 3, 2025, draft 
SIP supplement was submitted to EPA.

II. Background and Requirements for Regional Haze Plans

    A detailed history and background of the regional haze program is 
provided in prior EPA proposal action.\1\ For additional background on 
the 2017 RHR revisions, please refer to Section III. Overview of 
Visibility Protection Statutory Authority, Regulation, and 
Implementation of ``Protection of Visibility: Amendments to 
Requirements for State Plans'' of the 2017 RHR.\2\ The following is an 
abbreviated history and background of the regional haze program and 
2017 Regional Haze Rule as it applies to the current action.
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    \1\ See 90 FR 13516 (March 24, 2025).
    \2\ See 82 FR 3078 (January 10, 2017).
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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.\3\ 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).
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    \3\ 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.
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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.\4\
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    \4\ There are several ways to measure the amount of visibility 
impairment, i.e., haze. One such measurement is the deciview, which 
is the principal metric used by the RHR. Under many circumstances, a 
change in one deciview will be perceived by the human eye to be the 
same on both clear and hazy days. The deciview is unitless. It is 
proportional to the logarithm of the atmospheric extinction of 
light, which is the perceived dimming of light due to its being 
scattered and absorbed as it passes through the atmosphere. 
Atmospheric light extinction (b\ext\) is a metric used for 
expressing visibility and is measured in inverse megameters 
(Mm-1). 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); \5\ see also 40 CFR 
51.308(b), (f) (establishing submission dates for iterative regional 
haze SIP revisions); (64 FR at 35768, July 1, 1999).
    On January 10, 2017 (82 FR 3078), EPA promulgated revisions to the 
RHR, that apply for the second and subsequent implementation periods. 
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).

B. Roles of Agencies in Addressing Regional Haze

    Five regional planning organizations (RPOs) were developed in the 
lead-up to the first implementation period to address regional haze. 
The Lake Michigan Air Directors Consortium (LADCO), one of the five 
RPOs, 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 Midwest. LADCO member 
States are Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin. 
The LADCO Regional Haze Technical Workgroup also includes Tribes, Iowa, 
EPA, U.S. National Park 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 \6\ and (f)(4) through (6) containing 
additional, related requirements. Broadly speaking, a State first must 
identify the Class I areas within the State and determine the Class I 
areas outside the State in which visibility may be affected by 
emissions from the State. These are the Class I areas that must be 
addressed in the State's long-term strategy. See 40 CFR 51.308(f), 
(f)(2). For each Class I area within its borders, a State must then 
calculate the baseline (five-year average period of 2000-2004), 
current, and natural visibility conditions (i.e., visibility conditions 
without anthropogenic visibility impairment) for that area, as well as 
the visibility improvement made to date and the ``uniform rate of 
progress'' (URP). The

[[Page 25977]]

URP is 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 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. 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'' \7\ 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)-(3). There are additional requirements in 
the rule, including FLM consultation, that apply to all visibility 
protection SIPs and SIP revisions. See e.g., 40 CFR 51.308(i).
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    \6\ 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).
    \7\ The five ``additional factors'' for consideration in 40 
CFR51.308(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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A. Long-Term Strategy for Regional Haze

    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.\8\ This is accomplished by considering the four factors--``the 
costs of compliance, the time necessary for compliance, and the energy 
and non-air quality environmental impacts of compliance, and the 
remaining useful life of any existing source subject to such 
requirements.'' CAA 169A(g)(1). EPA has explained that the four-factor 
analysis is an assessment of potential emission reduction measures 
(i.e., control options) for sources; ``use of the terms `compliance' 
and `subject to such requirements' in section 169A(g)(1) strongly 
indicates that Congress intended the relevant determination to be the 
requirements with which sources would have to comply to satisfy the 
CAA's reasonable progress mandate.'' 82 FR 3091. Thus, for each source 
it has selected for four-factor analysis,\9\ a State must consider a 
``meaningful set'' of technically feasible control options for reducing 
emissions of visibility impairing pollutants. Id. at 3088.
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    \8\ 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.
    \9\ ``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 
3088.
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    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.\10\ 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.''
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    \10\ See, e.g., Responses to Comments on Protection of 
Visibility: Amendments to Requirements for State Plans; Proposed 
Rule (81 FR 26942, May 4, 2016) (December 2016), Docket Number EPA-
HQ-OAR-2015-0531, U.S. Environmental Protection Agency at 186.
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    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. If the outcome 
of a four-factor analysis is that an emissions reduction measure is 
necessary to make reasonable progress towards remedying existing or 
preventing future anthropogenic visibility impairment, that measure 
must be included in the SIP.
    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 is a technically complex exercise, and 
also a flexible one that provides States with bounded discretion to 
design and implement approaches appropriate to their circumstances. 
Given this flexibility, 40 CFR 51.308(f)(2)(iii) plays an important 
function in requiring a State to document the technical basis for its 
decision making so that the public and EPA can comprehend and evaluate 
the information and analysis the State relied upon to determine what 
emission reduction measures must be in place to make reasonable 
progress. The technical documentation must include the modeling, 
monitoring, cost, engineering, and emissions information on which the 
State relied to determine the measures necessary to make reasonable 
progress. Additionally, the RHR at 40 CFR 51.3108(f)(2)(iv) separately 
provides five

[[Page 25978]]

``additional factors'' \11\ that States must consider in developing 
their long-term strategies: (1) Emission reductions due to ongoing air 
pollution control programs, including measures to address reasonably 
attributable visibility impairment; (2) measures to reduce the impacts 
of construction activities; (3) source retirement and replacement 
schedules; (4) basic smoke management practices for prescribed fire 
used for agricultural and wildland vegetation management purposes and 
smoke management programs; and (5) the anticipated net effect on 
visibility due to projected changes in point, area, and mobile source 
emissions over the period addressed by the long-term strategy.
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    \11\ The five ``additional factors'' for consideration in 40 CFR 
51.308(f)(2)(iv) are distinct from the four factors listed in CAA 
section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that States must 
consider and apply to sources in determining reasonable progress.
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    Because the air pollution that causes regional haze crosses State 
boundaries, 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. 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). 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).

B. Reasonable Progress Goals (RPGs)

    RPGs ``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 3091.
    For the second implementation period, the RPGs are set for 2028. 
RPGs are not enforceable targets, 40 CFR 51.308(f)(3)(iii). 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.''
    RPGs may also serve as a metric for assessing the amount of 
progress a State is making towards the national visibility goal. To 
support this approach, the RHR requires States with Class I areas to 
compare the 2028 RPG for the most impaired days to the corresponding 
point on the URP line (representing visibility conditions in 2028 if 
visibility were to improve at a linear rate from conditions in the 
baseline period of 2000-2004 to natural visibility conditions in 2064). 
If the most impaired days RPG in 2028 is above the URP (i.e., if 
visibility conditions are improving more slowly than the rate described 
by the URP), each State that contributes to visibility impairment in 
the Class I area must demonstrate, based on the four-factor analysis 
required under 40 CFR 51.308(f)(2)(i), that no additional emission 
reduction measures would be reasonable to include in its long-term 
strategy. 40 CFR 51.308(f)(3)(ii). To this end, 40 CFR 51.308(f)(3)(ii) 
requires that each State contributing to visibility impairment in a 
Class I area that is projected to improve more slowly than the URP 
provide ``a robust demonstration, including documenting the criteria 
used to determine which sources or groups [of] sources were evaluated 
and how the four factors required by paragraph (f)(2)(i) were taken 
into consideration in selecting the measures for inclusion in its long-
term strategy.''

C. Monitoring Strategy and Other SIP 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 section apply either to States with Class I 
areas within their borders, States with no Class I areas but that are 
reasonably anticipated to cause or contribute to visibility impairment 
in any Class I area, or both. Compliance with the monitoring strategy 
requirement may be met through a State's participation in the 
Interagency Monitoring of Protected Visual Environments (IMPROVE) 
monitoring network, which is used to measure visibility impairment 
caused by air pollution at the 156 Class I areas covered by the 
visibility program. 40 CFR 51.308(f)(6), (f)(6)(i), (f)(6)(iv).
    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, as well as a statewide inventory documenting 
such emissions. 40 CFR 51.308(f)(6)(ii), (iii), (v). 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).

D. Requirements for Periodic Reports Describing Progress Towards the 
RPGs

    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 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 3119, January 
10, 2017). To this end, every State's SIP revision for the second 
implementation period is required to assess changes in visibility 
conditions and 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).

E. Requirements for State and Federal Land Manager Coordination

    CAA section 169A(d) requires that before a State holds a public 
hearing on a proposed regional haze SIP revision, it must consult with 
the appropriate FLM or FLMs; pursuant to that consultation, the State 
must include a summary of the FLMs' conclusions and recommendations in 
the notice to the public. Consistent with this statutory requirement, 
the RHR also requires that States ``provide the [FLM] with an 
opportunity for consultation, in person and at a point early enough in 
the State's policy analyses of its long-term strategy emission 
reduction obligation so that information and recommendations provided 
by the [FLM] can meaningfully inform the State's decisions on the long-
term strategy.'' 40 CFR 51.308(i)(2). For EPA

[[Page 25979]]

to evaluate whether FLM consultation meeting the requirements of the 
RHR has occurred, the SIP submission should include documentation of 
the timing and content of such consultation. The SIP revision submitted 
to EPA must also describe how the State addressed any comments provided 
by the FLMs. 40 CFR 51.308(i)(3). Finally, a SIP revision must provide 
procedures for continuing consultation between the State and FLMs 
regarding the State's visibility protection program, including 
development and review of SIP revisions, five-year progress reports, 
and the implementation of other programs having the potential to 
contribute to impairment of visibility in Class I areas. 40 CFR 
51.308(i)(4).

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

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

    Please see section 2 of the May 22, 2025, technical support 
document (TSD) accompanying this rule for background on EGLE's first 
implementation period plan.

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

    In accordance with CAA section 169A and the RHR at 40 CFR 
51.308(f), on August 23, 2021, and supplemented on April 3, 2025, EGLE 
submitted a revision to the Michigan SIP to address its regional haze 
obligations for the second implementation period that runs through 
2028.
    The following sections describe EGLE's SIP submission, including 
analyses conducted by LADCO and EGLE's determinations based on those 
analyses, EGLE's assessment of progress made since the first 
implementation period in reducing emissions of visibility impairing 
pollutants, and the visibility improvement progress at its Class I 
areas and nearby Class I areas. This proposed rulemaking and the 
accompanying May 22, 2025, TSD also contain EPA's evaluation of EGLE'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 paragraph (f)(2), which requires each State's plan to 
include a long-term strategy that addresses regional haze in such Class 
I areas.
    Michigan has two mandatory Class I Federal areas: Isle Royale 
National Park (Isle Royale) and Seney National Wildlife Refuge (Seney). 
LADCO performed a technical analysis to help assess state-level 
contributions to visibility impairment at Class I areas for the second 
implementation period. EGLE provided the analysis in section 2.1, 
Tables 6 and 7 of its supplement.
    Based on LADCO's source apportionment modeling results for 2028, 
Michigan was projected to have the greatest visibility impact on the 
Class I areas within the State, Seney and Isle Royale, contributing an 
estimated 3.4 Mm-1 and 1.7 Mm-1 of visibility 
impairment, respectively. This represents about 6.0 percent of the 
total light extinction at Seney and 3.5 percent at Isle Royale. 
Michigan also identified 13 out-of-state Class I areas where Michigan's 
contribution to the total light extinction was 1 percent or greater. In 
addition, Michigan identified the two Class I areas in Minnesota since 
they are also located within LADCO, although the projected impacts to 
these out-of-state areas are less than 1 percent at both Voyageurs 
National Park and Boundary Waters Canoe Area Wilderness (0.2 
Mm-1 and 0.3 Mm-1 impairment, respectively).

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

    The regulation at 40 CFR 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).
    EGLE provided this analysis for Isle Royale and Seney in section 2 
of its 2021 submission with updates in section 6 of its supplement. The 
2002 to 2004 observed baseline visibility conditions for Isle Royale 
are 6.77 deciviews (dv) on the 20 percent clearest days and 19.63 dv on 
the 20 percent most impaired days. For Seney, the baseline visibility 
is 7.14 dv on the 20 percent clearest days and 23.58 dv on the 20 
percent most impaired days. The natural conditions at Isle Royale are 
3.72 dv on the 20 percent clearest days and 10.17 dv on the 20 percent 
most impaired days. Natural conditions at Seney are 3.74 dv on the 20 
percent clearest days and 11.11 dv on the 20 percent most impaired 
days. Current conditions, based on 2014 to 2018 monitoring data, at 
Isle Royale are 15.54 dv on the 20 percent most impaired days and 5.30 
dv on the 20 percent clearest days. At Seney, the current conditions, 
based on 2014 to 2018 monitoring data, are 17.57 dv on the 20 percent 
most impaired days and 5.27 dv on the 20 percent clearest days. Based 
on the ambient data trends, steady progress towards natural conditions 
is being made at both Isle Royale and Seney.
    EGLE calculated the URP for the Class I areas for 2028 using 
LADCO's 2016 base year modeling. The 2028 URP is 15.85 dv at Isle 
Royale and 18.59 dv at Seney on the most impaired days. EGLE projects 
14.83 dv impairment at Isle Royale and 16.67 dv at Seney on the most 
impaired days, which are 1.02 dv and 1.92 dv below the URP, 
respectively.
    EPA proposes to find that EGLE has submitted a regional haze plan 
that meets the requirements of 40 CFR 51.308(f)(1) related to the 
calculations of baseline, current, and natural visibility conditions; 
progress to date; and the URP for the second implementation period.

E. Long-Term Strategy for Regional Haze

1. Emission Measures Necessary To Make Reasonable Progress
    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). After considering the four statutory factors, 
all measures that are determined to be necessary to make reasonable 
progress must be in the long-

[[Page 25980]]

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).
    EGLE details its measures necessary to make reasonable progress in 
section 5.2 of its supplement. EGLE's long-term strategy includes VOC 
Control Techniques, National Emission Standards for Hazardous Air 
Pollutants for some source categories, New Source Performance Standards 
for solid waste incinerators and for residential wood heaters, Federal 
onroad mobile sources rules, and several Federal non-road mobile 
sources rules among other Federal measures.
    EGLE's supplement builds on the long-term strategy presented in 
EGLE's August 23, 2021, submission. In developing its long-term 
strategy, EGLE considered both the four-factor analyses under 40 CFR 
51.308(f)(2)(i) and the five additional factors under 40 CFR 
51.308(f)(2)(iv). As required by 51.308(f)(2)(iv)(A), EGLE considered 
emission reductions due to ongoing air pollution control programs, 
referring to Federal emission control programs and documenting emission 
reductions at its sources that have reduced visibility impact at all 
Class I areas. As required by 40 CFR 51.308(f)(2)(iv)(B), EGLE noted 
its measures to mitigate the impacts of construction activities. 
Pursuant to 40 CFR 51.308(f)(2)(iv)(C), EGLE addressed schedules for 
source retirements and replacements. EGLE remarked that any major 
stationary source upon restart is subject to permitting as a new source 
and must comply with requirements pertaining to New Source Review and 
Prevention of Significant Deterioration.\12\ To satisfy the 
requirements of 40 CFR 51.308(f)(2)(iv)(D), EGLE considered smoke 
management techniques for the purposes of agricultural and forestry 
management in developing its long-term strategy. EGLE determined that 
emissions from prescribed fires are not significantly affecting Class I 
areas in Michigan. Thus, EGLE considered its smoke management strategy 
to be adequate for long-term progress. Additionally, as required by 40 
CFR 51.308(f)(2)(iv)(E), EGLE considered the anticipated net effect on 
visibility improvements due to projected changes in emissions from 
point, area, and mobile sources during the second implementation 
period, explaining that the visibility improvement expected was 
estimated using LADCO's 2016 base year and 2028 modeled projections. 
Given the information EGLE provided in this regard, EPA proposes to 
find that Michigan reasonably considered and satisfied the requirements 
for each of the five additional factors in 40 CFR 51.308(f)(2)(iv) in 
developing its long-term strategy.
---------------------------------------------------------------------------

    \12\ See ``Affirmation of EPA's Long-Standing Reactivation 
Policy'' in Attachment 2 of the November 16, 2022, memo from Joseph 
Goffman, EPA, Principal Deputy Assistant Administrator.
---------------------------------------------------------------------------

2. EPA's Evaluation of EGLE's Compliance With 40 CFR 51.308(f)(2)(i)
    The requirements of 40 CFR 51.308(f)(2)(i) relate to evaluating 
sources and determining the emission reduction measures that are 
necessary to make reasonable progress by considering the four statutory 
factors.
    Considering the four statutory factors, current effective control 
technologies, emission reductions that have already occurred during the 
second implementation period, and projected 2028 visibility conditions 
for Class I areas influenced by emissions from Michigan sources are all 
below the URP in 2028, EPA also finds it reasonable to conclude that no 
additional measures are necessary to make reasonable progress in the 
second implementation period. As detailed further later in this rule, 
EPA proposes to approve EGLE's long-term strategy under 40 CFR 
51.308(f)(2).
    In line with recent proposals from EPA,\13\ it is the Agency's 
policy that, where visibility conditions for a Class I area impacted by 
a State are below the URP and the State has considered the four 
statutory factors, the State will have presumptively demonstrated 
reasonable progress for the second implementation period for that Class 
I area. As previously discussed, for each Class I area, there is a 
regulatory requirement to compare the projected visibility impairment 
(represented by the RPG) at the end of each implementation period to 
the URP (e.g., in 2028 for the second implementation period).\14\
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    \13\ 90 FR 16478, April 18, 2025; see pages 16483 and 16484.
    \14\ We note that RPGs are a regulatory construct that we 
developed to address statutory mandate in section 169B(e)(1), which 
required our regulations to include ``criteria for measuring 
`reasonable progress' toward the national goal.'' Under 40 CFR 
51.308(f)(3)(ii), RPGs measure the progress that is projected to be 
achieved by the control measures a State has determined are 
necessary to make reasonable progress. Consistent with the 1999 RHR, 
the RPGs are unenforceable, though they create a benchmark that 
allows for analytical comparisons to the URP and mid-implementation-
period course corrections if necessary. 82 FR 3091-3092.
---------------------------------------------------------------------------

    EPA's new policy is that so long as the Class I areas impacted by a 
State are below the URP and the State considers the four factors, the 
State will have presumptively demonstrated it has already made 
reasonable progress for the second implementation period for that area. 
EPA believes this policy also recognizes the considerable improvements 
in visibility impairment that have been made by a wide variety of State 
and Federal programs in recent decades.
    Applying this new policy in our evaluation of EGLE's plan and as 
further detailed in the paragraphs that follow, EPA agrees with EGLE's 
determination that, for the second implementation period, no additional 
measures are necessary to achieve reasonable progress towards natural 
visibility at Class I areas both in Michigan and other States that are 
influenced by emissions from Michigan sources.
    The SIP submission included evaluations for 19 emissions sources, 
including consideration of the four statutory factors for three 
facilities and consideration of existing control measures and emission 
reductions at 16 facilities. Based on these evaluations and analyses, 
EGLE did not submit to EPA any additional measures for reasonable 
progress. In reaching this determination, EGLE also considered the 
emissions reductions and visibility improvements that have already 
occurred in the second implementation period in nearby Class I areas.
    EGLE generated a list of sources based on total process-level 
emissions (Q) divided by distance (d) to the nearest Class I area, 
where Q/d was used as a surrogate quantitative metric of visibility 
impact in lieu of air quality modeling results. For Q, EGLE used the 
combined emissions of NOX, SO2, PM2.5, 
VOC, and NH3 for its unit and facility emissions. EGLE 
selected sources to capture approximately 80 percent of NOX 
and SO2 emissions from all sources statewide as detailed in 
section 3.2.2 of its supplement. To capture 80 percent of 
NOX and SO2 emissions, EGLE set a pollutant 
specific Q/d threshold of greater than six at the unit level for 
NOX or SO2 emissions. That Q/d threshold 
identified 11 sources that have since experienced permanent emission 
reductions representing 30 percent of the NOX and 65 percent 
of the SO2 from all units in the second implementation 
period with a sum Q/d of 1 or greater

[[Page 25981]]

based on the 2016 inventory. EGLE then selected the remaining 13 units 
at eight facilities for potential further analysis. EGLE selected 
Tilden Mining Company, Kilns 1 and 2, St. Clair/Belle River Power 
Plant, Belle River Units 1 and 2, Empire Iron Mining Partnership, Units 
2, 3, and 4, St. Mary's Cement, Inc., Charlevoix Plant, Compiled Kiln, 
Holcim (US) Inc., DBA Lafarge Alpena Plant, Kilns 22 and 23, Billerud 
Escanaba LLC, Number 11 Power Boiler, Neenah Paper Michigan Inc., 
Munising, Boiler 1, and Graymont Western Lime, Inc., Kiln 1. EGLE 
provided this information on Tables 8 and 9 in section 3.2.2 of its 
supplement. EPA further summarizes EGLE's source selection in section 3 
of the May 22, 2025, TSD.
    From the list of selected sources, EGLE determined that several of 
the facilities either have idled indefinitely or have existing 
effective controls. EGLE selected the remaining three sources for a 
four-factor analysis for potential emissions controls. EGLE provided 
this information in section 3.3 of its supplement.
    EGLE performed four-factor analyses on the three selected sources 
to address the requirements of 40 CFR 51.308(f)(2)(i). For each four-
factor analysis, EGLE considered the cost of compliance, time necessary 
to install the controls, energy and non-air impacts, and remaining 
useful life of the sources. See CAA 169A(g)(1). Those analyses for 
Billerud Escanaba LLC, Graymont Western Lime Inc., and Tilden Mining 
Company are given in sections 4.1, 4.2, and 4.3 of EGLE's supplement. 
Upon considering the four statutory factors, EGLE ultimately determined 
that no additional controls were necessary for reasonable progress for 
the second implementation period. EGLE found no new measures to be cost 
effective for Billerud Escanaba LLC. For Graymont Western Lime Inc., 
EGLE determined fuel substitution to be a potentially cost-effective 
measure but expects ``a minimal or potentially unfavorable impact'' on 
annual NOX emissions and thus EGLE eliminated that measure. 
EGLE determined no new control measures on Tilden Kiln 2 are necessary 
to make reasonable progress based on a finding of negligible visibility 
improvement at both Isle Royale and Seney. See section 4 of the May 22, 
2025, TSD for details of the emission control measures evaluated. EPA 
concludes that EGLE appropriately considered the four statutory factors 
and determined additional controls were not cost-effective for the 
second implementation period.
    EGLE evaluated the on-the-books and on-the-way controls and did not 
request for any of those measures to be incorporated by reference into 
the regulatory portion of Michigan's SIP at 40 CFR 52.1170.
    EPA proposes to find that EGLE has satisfied the requirements of 40 
CFR 51.308(f)(2)(i) related to evaluating sources and determining the 
emission reduction measures that are necessary to make reasonable 
progress by applying the four statutory factors to sources in a control 
analysis. EGLE's SIP submission reasonably applied their source 
selection process, identifying sources accounting for approximately 80 
percent of NOX and SO2 emissions. In addition, 
EGLE adequately explained its decision to focus on the two pollutants, 
SO2 and NOX, that currently drive visibility 
impairment within the LADCO region. EPA proposes to find that EGLE 
adequately supported its conclusions for its top-impacting sources in 
determining that no additional measures are necessary for reasonable 
progress in the second implementation period. EPA is basing this 
proposed finding on EGLE's consideration of the four statutory factors, 
the projected 2028 visibility conditions for Class I areas, both in 
Michigan and influenced by emissions from Michigan sources, which are 
all below the URP in 2028, emission reductions that have already 
occurred during the second implementation period, and current effective 
control technologies.
    EPA proposes to find that EGLE's 2021 SIP submission and draft SIP 
supplement meets the CAA and regulatory requirement to make reasonable 
progress towards the national visibility goal. No measures are proposed 
to be incorporated by reference into the Michigan SIP.

F. RPGs

    Section 51.308(f)(3) contains the requirements pertaining to RPGs 
for each Class I area. Michigan contains two Class I areas, making it 
subject to 40 CFR 51.308(f)(3)(i). 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)(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.
    EGLE determined the RPGs using EPA's inventory and modeling 
provided by LADCO. LADCO used the National Emissions Inventory 
Collaborative's 2016 emissions inventory with updates to project 2028 
emissions.
    According to that modeling, the 2028 RPGs for the 20 percent most 
impaired days are 14.83 dv for Isle Royale and 16.67 dv for Seney. The 
2028 RPGs for the 20 percent clearest days are 5.23 dv for Isle Royale 
and 5.17 dv for Seney. See section 6 of the supplement including Tables 
32 and 33. EGLE included these RPGs in its regional haze plan for the 
second implementation period. EGLE's long-term strategy and the RPGs 
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, in accordance with 40 CFR 
51.308(f)(3)(i).
    Section 51.308(f)(3)(i) also specifies that RPGs must reflect 
``enforceable emissions limitations, compliance schedules, and other 
measures required under paragraph (f)(2) of this section'' (emphasis 
added). EPA interprets this provision as requiring that only emission 
reduction measures that States--including upwind States--have 
determined to be necessary for reasonable progress and incorporated 
into their long-term strategies be reflected in a Class I area's RPGs. 
This ensures that RPGs include only those measures that are reasonably 
certain to be implemented.
    The RHR at 40 CFR 51.308(f)(3)(iii) notes that the RPGs are not 
directly enforceable but will be considered by the Administrator in 
evaluating the adequacy of the measures in the implementation plan in 
providing for reasonable progress towards achieving natural visibility 
conditions at that area.
    Under 40 CFR 51.308(f)(3)(ii)(A), a State with a Class I area that 
establishes an RPG for the most impaired days that provides for a 
slower rate of improvement in visibility than the URP must calculate 
the number of years required to reach natural conditions. The 
demonstration requirement under 40 CFR 51.308(f)(3)(ii)(A) is not 
triggered because EGLE's RPGs are below the URP.

[[Page 25982]]

    Under 40 CFR 51.308(f)(3)(ii)(B), if a State 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, then the State must demonstrate that there are no 
additional emission reduction measures that would be reasonable to 
include in its long-term strategy. The out-of-state Class I areas with 
2028 projected contributions to total visibility impairment greater 
than 1 percent from Michigan that are listed in Table 7 of the 
supplement are well below the URP. Thus, EPA proposes to conclude that 
the demonstration requirement under 40 CFR 51.308(f)(3)(ii)(B) is not 
triggered.
    In sum, EPA proposes to determine that EGLE has satisfied the 
applicable requirements of 40 CFR 51.308(f)(3) relating to RPGs.

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 IMPROVE network.
    EGLE uses its participation in the IMPROVE program \15\ to meet the 
40 CFR 51.308(f)(6) monitoring strategy requirements. See section H.3 
of EGLE's submission.
---------------------------------------------------------------------------

    \15\ The IMPROVE sites also provide PM2.5 speciation 
data. Therefore, these sites are a key component of EPA's national 
fine particle monitoring in addition to being critical to tracking 
progress related to regional haze regulations.
---------------------------------------------------------------------------

    The obligations of 40 CFR 51.308(f)(6)(iii) only apply to States 
without a Class I area, requiring procedures for using monitoring data 
in determining the contribution of emissions to visibility impairment 
at Class I areas in other States. Michigan has Class I areas, so this 
requirement does not apply.
    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. EGLE backs the 
IMPROVE monitoring network as stated in H.3 of EGLE's submission.
    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. EGLE included LADCO's emission inventories 
in its plan. The emissions inventory includes VOC, NOX, 
PM2.5, NH3, and SO2. See appendix 2 of 
EGLE's supplement.
    The provisions of 40 CFR 51.308(f)(6)(v) also require States to 
include estimates of future projected emissions and include a 
commitment to update the inventory periodically. EGLE produces 
inventories meeting Federal requirements as noted in H.3 of EGLE's 
submission.
    The provisions of 40 CFR 51.308(f)(6)(vi) require a State to 
consider other elements necessary to assess and report on visibility, 
including reporting and recordkeeping. EGLE has met the other 
applicable requirements of 40 CFR 51.308(f)(6), therefore no further 
elements are necessary for it to assess and report on visibility 
pursuant to 40 CFR 51.308(f)(6)(vi).
    EPA proposes to find that EGLE has met the requirements of 40 CFR 
51.308(f)(6) through its continued participation in the IMPROVE 
network, its contribution analysis, its emissions reporting to EPA, and 
its statewide emissions inventory.

H. Requirements for Periodic Reports Describing Progress Towards the 
RPGs

    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. 
Applying to all States, 40 CFR 51.308(g)(1) and (2) require a 
description of the status of implementation of all measures included in 
a State's first implementation period regional haze plan and a summary 
of the emission reductions achieved through implementation of those 
measures. The regulations in 40 CFR 51.308(g)(3) apply only to States 
with Class I areas within their borders and require such States to 
assess current visibility conditions, changes in visibility relative to 
baseline (2000 to 2004) visibility conditions, and changes in 
visibility conditions relative to the period addressed in the first 
implementation period progress report. The regulations in 40 CFR 
51.308(g)(4) apply to all States and require an analysis tracking 
changes in emissions of pollutants contributing to visibility 
impairment from all sources and sectors since the period addressed by 
the first implementation period progress report. This provision further 
specifies the year or years through which the analysis must extend 
depending on the type of source and the platform through which its 
emission information is reported. Finally, 40 CFR 51.308(g)(5), which 
also applies to all States, requires an assessment of whether 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.
    EGLE submitted its previous progress report on January 12, 2016, 
which covered visibility data through 2014. Thus, EGLE's progress 
report covers the period of 2015 to 2019.
    EGLE, in section 8.3 of its supplement, provides its progress 
report for the second half of the first period. EGLE describes the 
status of emission reduction measures from the first implementation 
period as required by 40 CFR 51.308(g)(1). EGLE gives the status of 
emission reduction measures at Holcim US DBA Lafarge Alpena Plant, 
Billerud Escanaba, LLC, Saint Mary's Cement--Charlevoix Plant, Smurfit 
Stone Container Corporation, and Tilden Mining Company, LLC. In section 
8.3.2 of the supplement, EGLE gives the annual NOX and 
SO2 emissions for each non-EGU source to summarize the 
emission reductions from regional haze strategies as required by 40 CFR 
51.308(g)(2).
    EPA proposes to find that EGLE has met the requirements of 40 CFR 
51.308(g)(1) and (2) because its submission gives the status of 
implementation of first period emission reduction measures and a 
summary of the emission reductions achieved through such 
implementation.
    States are required by 40 CFR 51.308(g)(3) to assess the visibility 
progress of its Class I areas. In section 8.3.3 of its supplement, EGLE 
provided the 2014 and 2019 IMPROVE visibility data for its Class I 
areas demonstrating improvement in visibility during both the clearest 
and most impaired days. In 2019, the IMPROVE monitor at Isle Royale 
demonstrated a 5-year average light extinction of 14.9 dv, down from 
17.3 dv in 2014 for the most impaired days. Light extinction at Seney 
also decreased from 19.5 dv to 17.1 dv over the same time period. For 
the clearest

[[Page 25983]]

days, Isle Royale's average light extinction decreased from 5.5 dv in 
2014 to 5.1 dv in 2019. Similarly, light extinction Seney also 
decreased from 5.5 dv to 5.1 dv over the same period. EPA proposes to 
find that EGLE has satisfied the requirements of 40 CFR 51.308(g)(3).
    Pursuant to 40 CFR 51.308(g)(4), EGLE provided LADCO's emission 
inventories in appendix 2 to its supplement. LADCO gives the 2011 and 
2016 NH3, NOX, PM2.5, SO2, 
and VOC emissions from all sources and activities, including from 
point, nonpoint, non-road mobile, and on-road mobile sources for 
Michigan and the other five States. EPA proposes to find that EGLE has 
satisfied the requirements of 40 CFR 51.308(g)(4) by providing 
emissions information for NH3, NOX, 
PM2.5, SO2, and VOC emissions by source type.
    As for the requirement of 40 CFR 51.308(g)(5) to give an assessment 
of changes impeding visibility progress, EGLE evaluated contributions 
within and outside the State. EGLE states in section 8.3.4.3 of its 
supplement that it does not anticipate any significant changes in 
emissions within and from outside Michigan. EGLE remarked that while 
there have been increases in NOX and SO2 
emissions between 2014 and 2019 in some source categories within 
Michigan and in other States, it does not expect any impediment in 
visibility progress given the substantial emission reductions from 
other sources that have occurred during the second implementation 
period. EPA proposes to find that EGLE has met the requirements of 40 
CFR 51.308(g)(5).

I. Requirements for State and Federal Land Manager Coordination

    Section 169A(d) of the CAA requires States to consult with FLMs 
before holding the public hearing on a proposed regional haze SIP, and 
to include a summary of the FLMs' conclusions and recommendations in 
the notice to the public. In addition, 40 CFR 51.308(i)(2)'s FLM 
consultation provision requires a State to provide FLMs with an 
opportunity for consultation that is early enough in the State's policy 
analyses of its emission reduction obligation so that information and 
recommendations provided by the FLMs can meaningfully inform the 
State's decisions on its long-term strategy. If the consultation has 
taken place at least 120 days before a public hearing or public comment 
period, the opportunity for consultation will be deemed early enough. 
Regardless, the opportunity for consultation must be provided at least 
60 days before a public hearing or public comment period at the State 
level. Section 51.308(i)(2) 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.
    EGLE provided its February 2021 draft Regional Haze plan to the 
USFS, FWS, and the NPS for a 60-day review and comment period pursuant 
to 40 CFR 51.308(i)(2). A FLM consultation meeting was held on April 
29, 2021.
    On December 19, 2024, EGLE provided its regional haze plan 
supplement to USFS, FWS, and the NPS for a 60-day review and comment 
period. A consultation meeting was held on February 12, 2025. EGLE 
provided the FLM comments in appendix 30 of the supplement and its 
responses in appendix 32. EPA proposes to find that EGLE 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.
    EGLE published the public notice for the proposed update to 
Michigan's Regional Haze SIP on its website on May 17, 2021. The public 
comment period ran until June 30, 2021. A summary of the FLM and public 
comments along with EGLE's responses is found in the EGLE submission 
appendix D with the comments supplied in appendix E.
    EGLE published the public notice for a supplement to Michigan's 
Regional Haze SIP on its website on March 10, 2025. The public comment 
period on the supplement was from March 10, 2025, to April 22, 2025.

V. What action is EPA taking?

    EPA is proposing to approve the Regional Haze SIP revision 
submitted by EGLE on August 23, 2021, and supplemented on April 3, 
2025, as satisfying applicable requirements under the CAA and RHR for 
the program's second implementation period.

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the CAA and applicable 
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve State choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
action merely approves State law as meeting Federal requirements and 
does not impose additional requirements beyond those imposed by State 
law. For that reason, this action:
     Is not a significant regulatory action subject to review 
by the Office of Management and Budget under Executive Order 12866 (58 
FR 51735, October 4, 1993);
     Is not subject to Executive Order 14192 (90 FR 9065, 
February 6, 2025) because SIP actions are exempt from review under 
Executive Order 12866;
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not subject to Executive Order 13045 (62 FR 19885, 
April 23, 1997) because it approves a State program;
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001); and
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA.
    In addition, the SIP is not approved to apply on any Indian 
reservation land or in any other area where EPA or an Indian Tribe has 
demonstrated that a Tribe has jurisdiction. In those areas of Indian 
country, the rulemaking 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, Intergovernmental relations, Nitrogen dioxide, Reporting and 
recordkeeping requirements, Sulfur oxides.


[[Page 25984]]


    Dated: June 2, 2025.
Anne Vogel,
Regional Administrator, Region 5.
[FR Doc. 2025-11257 Filed 6-17-25; 8:45 am]
BILLING CODE 6560-50-P