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Proposed Rule2025-08072

Air Plan Approval; South Dakota; Regional Haze Plan for the Second Implementation Period

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Published

May 14, 2025

Issuing agencies

Environmental Protection Agency

Abstract

The Environmental Protection Agency (EPA) is proposing to approve the regional haze state implementation plan (SIP) submission submitted by the State of South Dakota on July 29, 2022 (South Dakota's 2022 SIP submission), under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. South Dakota's 2022 SIP submission addresses the requirement that states revise their long-term strategies every implementation period to make 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. South Dakota's 2022 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 the CAA.

Full Text

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<title>Federal Register, Volume 90 Issue 92 (Wednesday, May 14, 2025)</title>
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[Federal Register Volume 90, Number 92 (Wednesday, May 14, 2025)]
[Proposed Rules]
[Pages 20425-20439]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-08072]

[[Page 20425]]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R08-OAR-2024-0609; FRL-12596-01-R8]

Air Plan Approval; South Dakota; Regional Haze Plan for the
Second Implementation Period

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve the regional haze state implementation plan (SIP) submission
submitted by the State of South Dakota on July 29, 2022 (South Dakota's
2022 SIP submission), under the Clean Air Act (CAA) and the EPA's
Regional Haze Rule (RHR) for the program's second implementation
period. South Dakota's 2022 SIP submission addresses the requirement
that states revise their long-term strategies every implementation
period to make 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. South Dakota's 2022 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 the
CAA.

DATES: Written comments must be received on or before June 13, 2025.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R08-
OAR-2024-0609, to the Federal Rulemaking Portal: <a href="https://www.regulations.gov">https://www.regulations.gov</a>. Follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
<a href="https://www.regulations.gov">https://www.regulations.gov</a>. The EPA may publish any comment received
to its public docket. Do not submit electronically any information you
consider to be Confidential Business Information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, the full EPA public comment
policy, information about CBI or multimedia submissions, and general
guidance on making effective comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
Docket: All documents in the docket are listed in the <a href="https://www.regulations.gov">https://www.regulations.gov</a> index. Although listed in the index, some
information is not publicly available, e.g., CBI or other information
whose disclosure is restricted by statute. Certain other material, such
as copyrighted material, will be publicly available only in hard copy.
Publicly available docket materials are available electronically in
<a href="https://www.regulations.gov">https://www.regulations.gov</a>. Please email or call the person listed in
the FOR FURTHER INFORMATION CONTACT section if you need to make
alternative arrangements for access to the docket.

FOR FURTHER INFORMATION CONTACT: Joe Stein, Air and Radiation Division,
EPA, Region 8, Mailcode 8ARD-IO, 1595 Wynkoop Street, Denver, Colorado
80202-1129, telephone number: (303) 312-7078, email address:
<a href="/cdn-cgi/l/email-protection#562522333f38783c392533263e1633263778313920"><span class="__cf_email__" data-cfemail="9fecebfaf6f1b1f5f0ecfaeff7dffaeffeb1f8f0e9">[email&#160;protected]</span></a>.

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

Table of Contents

I. What action is the EPA proposing?
II. Background and Requirements for Regional Haze Plans
A. Regional Haze
B. Roles of Agencies in Addressing Regional Haze
C. Status of South Dakota's Regional Haze Plan for the First
Implementation Period
D. South Dakota's Regional Haze Plan for the Second
Implementation Period
III. Requirements for Regional Haze Plans for the Second
Implementation Period
A. Reasonable Progress Goals
B. Monitoring Strategy and Other State Implementation Plan
Requirements
C. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
D. Requirements for State and Federal Land Manager Coordination
IV. The EPA's Evaluation of South Dakota's Regional Haze Plan for
the Second Implementation Period
A. Identification of Class I Areas
B. Calculation of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and Uniform Rate of Progress for Class
I Areas Within the State
C. Long-Term Strategy
1. Summary of South Dakota's Long-Term Strategy
a. GCC Dacotah
b. Pete Lien and Sons
c. Summary of South Dakota's Reasons for Concluding That No
Additional Emission Reduction Measures Are Necessary To Make
Reasonable Progress
2. The EPA's Evaluation of South Dakota's Long-Term Strategy
a. GCC Dacotah
b. Pete Lien and Sons
c. Other Long-Term Strategy Requirements (40 CFR
51.308(f)(2)(ii) Through (iv))
D. Reasonable Progress Goals
E. Reasonably Attributable Visibility Impairment (RAVI)
F. Monitoring Strategy and Other State Implementation Plan
Requirements
G. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
H. Requirements for State and Federal Land Manager Coordination
V. Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is the EPA proposing?

The EPA is proposing to approve a SIP submission submitted by the
State of South Dakota to the EPA on July 29, 2022, addressing the
requirements of the second implementation period of the RHR.
Specifically, the EPA is proposing to approve South Dakota's 2022 SIP
submission as satisfying the requirements of 40 CFR 51.308(f)(1):
calculations of baseline, current, and natural visibility conditions,
progress to date, and the uniform rate of progress; 40 CFR
51.308(f)(2): long-term strategy; 40 CFR 51.308(f)(3): reasonable
progress goals; 40 CFR 51.308(f)(4): reasonably attributable visibility
impairment; 40 CFR 51.308(f)(5) and 40 CFR 51.308(g): progress report
requirements; 40 CFR 51.308(f)(6): monitoring strategy and other
implementation plan requirements; and 40 CFR 51.308(i): Federal Land
Manager (FLM) consultation.

II. Background and Requirements for Regional Haze Plans

A detailed history and background of the regional haze program is
provided in multiple prior EPA proposal actions.\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), located at <a href="https://www.federalregister.gov/documents/2017/01/10/2017-00268/protection-of-visibility-amendments-to-requirements-for-State-plans#h-16">https://www.federalregister.gov/documents/2017/01/10/2017-00268/protection-of-visibility-amendments-to-requirements-for-State-plans#h-16</a>.
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A. Regional Haze

In the 1977 CAA amendments, Congress created a program for
protecting visibility in the Nation's mandatory Class I Federal areas,
which

[[Page 20426]]

include certain national parks and wilderness areas.\3\ CAA section
169A. The CAA establishes as a national goal the ``prevention of any
future, and the remedying of any existing, impairment of visibility in
mandatory Class I Federal areas which impairment results from manmade
air pollution.'' CAA section 169A(a)(1).
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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
section 162(a). There are 156 mandatory Class I areas. The list of
areas to which the requirements of the visibility protection program
apply is in 40 CFR part 81, subpart D.
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Regional haze is visibility impairment that is produced by a
multitude of anthropogenic sources and activities that 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 (SO<INF>2</INF>), nitrogen oxides (NO<INF>X</INF>), and, in
some cases, volatile organic compounds (VOC) and ammonia
(NH<INF>3</INF>)). Fine particle precursors react in the atmosphere to
form fine particulate matter (PM<INF>2.5</INF>), which impairs
visibility by scattering and absorbing light. Visibility impairment
reduces the perception of clarity and color, as well as visible
distance.\4\
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\4\ There are several ways to measure the amount of visibility
impairment, i.e., haze. One such measurement is the deciview, which
is the principal metric used by the RHR. Under many circumstances, a
change in one deciview will be perceived by the human eye to be the
same on both clear and hazy days. The deciview is unitless. It is
proportional to the logarithm of the atmospheric extinction of
light, which is the perceived dimming of light due to its being
scattered and absorbed as it passes through the atmosphere.
Atmospheric light extinction (b\ext\) is a metric used for
expressing visibility and is measured in inverse megameters
(Mm<SUP>-1</SUP>.
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To address regional haze visibility impairment, the 1999 RHR
established an iterative planning process that requires both states in
which Class I areas are located and states ``the emissions from which
may reasonably be anticipated to cause or contribute to any impairment
of visibility'' in a Class I area to periodically submit SIP revisions
to address such impairment. CAA section 169A(b)(2); \5\ see also 40 CFR
51.308(b), (f) (establishing submission dates for iterative regional
haze SIP revisions) (64 FR 35768, July 1, 1999).
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\5\ The RHR expresses the statutory requirement for states to
submit plans addressing out-of-state Class I areas by providing that
states must address visibility impairment ``in each mandatory Class
I Federal area located outside the State that may be affected by
emissions from within the State.'' 40 CFR 51.308(d), (f).
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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 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

Because the air pollutants and pollution affecting visibility in
Class I areas can be transported over long distances, successful
implementation of the regional haze program requires long-term,
regional coordination among multiple jurisdictions and agencies that
have responsibility for Class I areas and the emissions that impact
visibility in those areas. To address regional haze, states need to
develop strategies in coordination with one another, considering the
effect of emissions from one jurisdiction on the air quality in
another. Five regional planning organizations (RPOs),\6\ 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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\6\ 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 Western Regional Air Partnership (WRAP), one of the five
regional planning organizations described in the previous paragraph, is
a collaborative effort of state governments, local air agencies, 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 Western United States.
Members include the states of Alaska, Arizona, California, Colorado,
Hawaii, Idaho, Montana, Nevada, New Mexico, North Dakota, Oregon, South
Dakota, Utah, Washington, Wyoming, and 28 tribal governments.\7\ The
Federal partner members of WRAP are the EPA, U.S. National Parks
Service (NPS), U.S. Fish and Wildlife Service (USFWS), U.S. Forest
Service (USFS), and the Bureau of Land Management (BLM).
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\7\ A full list of WRAP members is available at <a href="https://www.westar.org/wrap-council-members/">https://www.westar.org/wrap-council-members/</a>.
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The WRAP membership formed a workgroup to develop a planning
framework for state regional haze second planning period SIPs. Based on
emissions and monitoring data supplied by its membership, WRAP produced
a technical system to support regional modeling of visibility impacts
at Class I areas across the West. The WRAP Technical Support System
consolidated air quality monitoring data, meteorological and receptor
modeling data analyses, emissions inventories and projections, and
gridded air quality/visibility regional modeling results. The Technical
Support System is accessible by member states and allows for the
creation of maps, figures, and tables to export and use in state plan
development. It also maintains the original source data for
verification and further analysis.

C. Status of South Dakota's Regional Haze Plan for the First
Implementation Period

The CAA requires that regional haze plans for the first
implementation period (2008 through 2018) include, among other things,
a long-term strategy for making reasonable progress and BART
requirements for certain older stationary sources, where applicable.\8\
In January 2011, South Dakota submitted a first implementation period
regional haze SIP submission addressing the requirements of 40 CFR
51.308. On April 26, 2012, the EPA approved the 2011 SIP submission as
meeting the requirements of the CAA and the RHR.\9\
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\8\ Requirements for regional haze SIPs for the first
implementation period are contained in CAA section 169A(b)(2). As
relevant to South Dakota, 40 CFR 51.308(d) and (e) require states to
perform individual point source BART determinations and evaluate the
need for other control strategies.
\9\ 77 FR 24845 (April 26, 2012).
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On January 27, 2016, South Dakota submitted its first planning
period progress report SIP submission. It detailed the State's progress
toward achieving reasonable progress for visibility improvement and
included a determination of adequacy of the State's regional haze
implementation plan to meet reasonable progress goals. In 2018, we
approved South Dakota's progress report SIP submission.\10\
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\10\ 83 FR 62262 (December 3, 2018).
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D. South Dakota's Regional Haze Plan for the Second Implementation
Period

On April 28, 2022, South Dakota submitted a SIP submission to
address its regional haze obligations for the second implementation
period (2018-

[[Page 20427]]

2028). South Dakota's 2022 SIP submission contains the State's
evaluation of which measures to include in its long-term strategy to
address regional haze visibility impairment for each Class I area
within the State and each Class I area outside the State that may be
affected by emissions from the State. The State examined the need to
implement additional enforceable emission limitations, compliance
schedules, and other measures that may be necessary to make reasonable
progress since the first implementation period. Specifically, South
Dakota's 2022 SIP submission contains an assessment of visibility
progress made at Class I areas since the first implementation period
and the State's determinations regarding a long-term strategy to
address regional haze visibility impairment at the Class I areas the
State identified, including: South Dakota's selection of sources that
may affect visibility in Class I areas for four-factor analysis; its
evaluation of the selected sources to determine what emission reduction
measures may be necessary to achieve reasonable progress for the long-
term strategy; WRAP's regional scale modeling of the State's long-term
strategy to set reasonable progress goals for 2028; and ultimately,
South Dakota's determinations on what measures are necessary for the
long-term strategy to address regional haze visibility impairment in
Class I areas. The State concluded that no additional emission
reduction measures for any South Dakota facilities are required for the
second implementation period under its long-term strategy.

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

Under the CAA and the EPA's regulations, all 50 states, the
District of Columbia, and the U.S. Virgin Islands are required to
submit regional haze SIPs satisfying the applicable requirements for
the second implementation period of the regional haze program by July
31, 2021. Each state's SIP must contain a long-term strategy for making
reasonable progress toward meeting the national goal of remedying any
existing and preventing any future anthropogenic visibility impairment
in Class I areas. CAA section 169A(b)(2)(B). To this end, 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 paragraphs (f)(1) through (3) generally mirroring the
order of the steps in the reasonable progress analysis \11\ and
paragraphs (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) introductory text, (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 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'' \12\ 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 reasonable
progress goals (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). 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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\11\ The EPA explained in the 2017 RHR Revisions that we were
adopting new regulatory language in 40 CFR 51.308(f) that, unlike
the structure in 40 CFR 51.308(d), ``tracked the actual planning
sequence.'' (82 FR 3091).
\12\ The five ``additional factors'' for consideration in Sec.
51.308(f)(2)(iv) are distinct from the four factors listed in CAA
section 169A(g)(1) and Sec. 51.308(f)(2)(i) that states must
consider and apply to sources in determining reasonable progress.
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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.\13\ 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 section 169A(g)(1). The EPA has explained that the
four-factor analysis is an assessment of

[[Page 20428]]

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,\14\ 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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\13\ The CAA provides that, ``[i]n determining reasonable
progress there shall be taken into consideration'' the four
statutory factors. CAA section 169A(g)(1). However, in addition to
four-factor analyses for selected sources, groups of sources, or
source categories, a state may also consider additional emission
reduction measures for inclusion in its long-term strategy, e.g.,
from other newly adopted, on-the-books, or on-the-way rules and
measures for sources not selected for four-factor analysis for the
second implementation period.
\14\ ``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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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.\15\ 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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\15\ 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 ID No. 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 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.
Additionally, the RHR at 40 CFR 51.3108(f)(2)(iv) separately
provides five ``additional factors'' \16\ that states must consider in
developing their long-term strategies: (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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\16\ The five ``additional factors'' for consideration in Sec.
51.308(f)(2)(iv) are distinct from the four factors listed in CAA
section 169A(g)(1) and Sec. 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).

A. 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 3091.
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). 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 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.''

[[Page 20429]]

B. 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 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) introductory text, (f)(6)(i),
(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), and (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).

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

Section 51.308(f)(5) requires a state's regional haze SIP revision
to address the requirements of 40 CFR 51.308(g)(1) through (5) so that
the plan revision due in 2021 will serve also as a progress report
addressing the period since submission of the progress report for the
first implementation period. The regional haze progress report
requirement is designed to inform the public and the EPA about a
state's implementation of its existing long-term strategy and whether
such implementation is in fact resulting in the expected visibility
improvement. See 81 FR 26942, 26950 (May 4, 2016) (82 FR 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).

D. 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 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. The EPA's Evaluation of South Dakota's Regional Haze Plan for the
Second Implementation Period

In section IV. of this document, we describe South Dakota's 2022
SIP submission and evaluate it against the requirements of the CAA and
RHR for the second implementation period of the regional haze program.

A. 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 long-term strategy for making reasonable
progress toward the national visibility goal. The RHR implements this
statutory requirement in 40 CFR 51.308(f) for the second and subsequent
planning periods for regional haze. Section 51.308(f)(2) requires
states to submit a long-term strategy that addresses regional haze
visibility impairment for each mandatory Class I area within the state
and for each mandatory Class I area located outside the state that may
be affected by emissions from the state.
There are two designated Class I Areas within the State of South
Dakota, including two national parks managed by the U.S. National Parks
Service: Badlands National Park and Wind Cave National Park.\17\ In its
2022 SIP submission, South Dakota acknowledges its sources'
contribution to visibility impairment at both Badlands and Wind
Cave.\18\ South Dakota maintains that Wind Cave is already projected to
meet natural visibility conditions by 2028.\19\ As shown in the SIP
submission, the 2028 ``on-the-books'' modeling scenario projects a
value of 9.76 deciviews (dv) impairment at Wind Cave, which is lower
than the level of estimated adjusted natural conditions at 10.06
dv.\20\ This visibility modeling is consistent with South Dakota's
statement that Wind Cave is projected to achieve adjusted natural
conditions by 2028, based on the adjustment applied by South Dakota,
which accounts for both international anthropogenic and prescribed fire
contributions. However, there is some uncertainty that Wind Cave will
reach natural conditions by 2028 because sources that contribute to
U.S. anthropogenic visibility impairment at Wind Cave will still be
operating in 2028. For example, WRAP's source apportionment modeling
shows that South Dakota sources contribute about 8% of U.S.
anthropogenic nitrate impairment and around 2.5% of U.S. anthropogenic
sulfate impairment at Wind Cave.\21\ In terms of total U.S.
anthropogenic impairment (nitrate and sulfate combined), South Dakota
contributes 5.5% of total anthropogenic impairment at Wind Cave.\22\
---------------------------------------------------------------------------

\17\ South Dakota's 2022 SIP submission at 17-21.
\18\ Id. at 78.
\19\ South Dakota's 2022 SIP submission at 161.
\20\ Id. at 166.
\21\ ``TSS XY Chart--Product #XMTP_SASB_LUCS.'' WRAP Technical
Support System (TSS); CSU and the Cooperative Institute for Research
in the Atmosphere (CIRA), 30 Dec 2024.
\22\ Id.
---------------------------------------------------------------------------

WRAP's source apportionment data also shows that South Dakota
sources contribute about 5.9% of anthropogenic nitrate impairment and
1.3% of anthropogenic sulfate impairment at Badlands.\23\ In terms of
total anthropogenic impairment (nitrate and sulfate combined), South
Dakota contributes around 3.5% of total

[[Page 20430]]

anthropogenic impairment at Badlands.\24\
---------------------------------------------------------------------------

\23\ Id.
\24\ Id.
---------------------------------------------------------------------------

There is also some uncertainty in the estimate of natural
conditions on the 20% most impaired days, and uncertainty in the
estimate of prescribed fire and international anthropogenic
contributions at Wind Cave that could skew calculations of adjusted
natural conditions. However, this uncertainty does not impact glidepath
status. Both Class I areas are projected to be well below the adjusted
glidepath for 2028,\25\ and in fact, Wind Cave is projected to be below
the unadjusted glidepath in 2028.\26\ Therefore, irrespective of any
adjustments, Wind Cave is clearly below the glidepath in 2028, and
Badlands is below the adjusted glidepath in 2028.
---------------------------------------------------------------------------

\25\ Id. at 159-176.
\26\ Id.
---------------------------------------------------------------------------

South Dakota also evaluated 10 Class I Areas outside the State
where visibility may be affected by South Dakota sources. South Dakota
concluded that its sources do not significantly impact these out-of-
state Class I areas (table 1).\27\ Based on our review of WRAP's source
apportionment data,\28\ we find that South Dakota's sources primarily
contribute to visibility impairment to the two in-state Class I areas
and have small contributions to several out-of-state Class I areas, in
alignment with South Dakota's analysis.
---------------------------------------------------------------------------

\27\ South Dakota 2022 SIP submission at 80 and 176-177.
\28\ Id.

Table 1--Class I Areas in Other States That May Be Affected by South
Dakota Sources
------------------------------------------------------------------------
State Class I area
------------------------------------------------------------------------
North Dakota.......................... Theodore Roosevelt National Park
North Dakota.......................... Lostwood Wilderness
Montana............................... Medicine Lake Wilderness
Montana............................... UL Bend Wilderness
Minnesota............................. Boundary Waters Wilderness
Minnesota............................. Voyageurs National Park
Wyoming............................... Bridger Wilderness
Wyoming............................... North Absaroka Wilderness
Colorado.............................. Mount Zirkel Wilderness
Colorado.............................. Rocky Mountain National Park
------------------------------------------------------------------------

B. Calculation of Baseline, Current, and Natural Visibility Conditions;
Progress to Date; and Uniform Rate of Progress for Class I Areas Within
the State

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).
The IMPROVE monitoring network measures visibility impairment
caused by air pollution at Class I areas. South Dakota's 2022 SIP
submission provides visibility conditions for each IMPROVE monitor and
associated Class I area in South Dakota (table 2).\29\
---------------------------------------------------------------------------

\29\ Id. at 24-29 and 39-44.

Table 2--Visibility Conditions (Deciviews) for South Dakota IMPROVE Stations
--------------------------------------------------------------------------------------------------------------------------------------------------------
Progress during Difference
Progress since last between
Baseline Period (2008- Current Natural baseline (2000- implementation current (2014-
Monitor ID Class I areas (2000-2004) 2012) (2014-2018) (2064) 2004)-- (2014- period (2008- 2018) and
2018) 2012)-- (2014- natural (2064)
2018)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Most Impaired Days
--------------------------------------------------------------------------------------------------------------------------------------------------------
BADL1................. Badlands National Park... 15 14.6 12.3 6.1 2.7 2.3 6.2
WICA1................. Wind Cave National Park.. 13.1 12.5 10.5 5.6 2.6 2 4.9
--------------------------------------------------------------------------------------------------------------------------------------------------------
Clearest Days
--------------------------------------------------------------------------------------------------------------------------------------------------------
BADL1................. Badlands National Park... 6.9 6.2 5.4 2.9 1.5 0.8 2.5
WICA1................. Wind Cave National Park.. 5.1 4.1 3.5 1.9 1.6 0.6 1.6
--------------------------------------------------------------------------------------------------------------------------------------------------------

The State also determined the uniform rate of progress for the most
impaired and clearest days for South Dakota Class I areas.\30\ Under 40
CFR 51.308(f)(1)(vi)(B), South Dakota chose to adjust the uniform rate
of progress glidepath for the State's two Class I Areas to account for
impacts from anthropogenic sources outside the United States and
impacts from wildland prescribed fires.\31\ \32\
---------------------------------------------------------------------------

\30\ Id. at 41-44.
\31\ Wildland prescribed fires are those conducted with the
objective to establish, restore, and/or maintain sustainable and
resilient wildland ecosystems, to reduce the risk of catastrophic
wildfires, and/or to preserve endangered or threatened species
during which appropriate basic smoke management practices were
applied. 40 CFR 51.308(f)(1)(vi)(B).
\32\ South Dakota 2022 SIP submission at 44-46.
---------------------------------------------------------------------------

Based on the information provided in chapter 2 of South Dakota's
2022 SIP submission, the EPA is proposing to approve the State's
visibility condition calculations for Badlands National Park and Wind
Cave National Park as meeting the requirements of 40 CFR 51.308(f)(1)
related to the calculation of baseline, current, and natural visibility
conditions; progress to date; and the URP. As discussed in section
IV.A., both Class I areas are projected to be below the adjusted
glidepath in 2028.\33\
---------------------------------------------------------------------------

\33\ Id. at 159-176.
---------------------------------------------------------------------------

C. Long-Term Strategy

Each state having a Class I area within its borders or emissions
that may affect visibility in any Class I area outside the state must
develop a long-term strategy for making reasonable progress towards the
national visibility goal for each impacted Class I area. CAA section
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-term strategy. In developing its long-term
strategy, 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

[[Page 20431]]

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).
1. Summary of South Dakota's Long-Term Strategy
South Dakota identified two Class I areas that must be addressed in
its long-term strategy: Badlands National Park and Wind Cave National
Park.\34\ Under 40 CFR 51.308(f)(2)(i), SIP submittals must include a
description of the criteria a state used to determine which sources or
groups of sources to evaluate through four-factor analysis. South
Dakota used Q/d screening and Weighted Emissions Potential/Area of
Influence (WEP/AOI) analysis to identify sources for four-factor
analysis. The Q/d screening metric uses a source's annual emissions in
tons (Q) divided by the distance in kilometers (d) between the source
and the nearest Class I area, along with a reasonably selected
threshold for this metric. The larger the Q/d value, the greater the
source's expected effect on visibility in each associated Class I area.
WEP is calculated by overlaying extinction weighted residence time
results with 2028OTBa2 emissions of light extinction precursors (i.e.,
NO<INF>X</INF> emissions for ammonium nitrate light extinction and
SO<INF>2</INF> emissions for ammonium sulfate light extinction).
Extinction weighted residence time is calculated by weighting Hybrid
Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) back
trajectories by the actual observed light extinction at IMPROVE sites
on each Most Impaired Day. The results are then normalized by the sum
of the WEP for the total anthropogenic emissions. WEP results include
percentages of the total for nitrates and sulfates and the rankings by
Class I areas.\35\
---------------------------------------------------------------------------

\34\ Id. at 121.
\35\ WRAP, ``WEP/AOI Analysis for western U.S. Class I Areas,''
<a href="https://views.cira.colostate.edu/tssv2/WEP-AOI">https://views.cira.colostate.edu/tssv2/WEP-AOI</a>/(last accessed
January 24, 2025).
---------------------------------------------------------------------------

Initially, using WRAP's source selection threshold of Q/d > 10,
South Dakota pulled only one source forward for analysis.\36\ To expand
its analysis and ensure that an adequate number of sources were
evaluated, South Dakota lowered its source selection threshold to Q/d >
2. Using a screening threshold of Q/d > 2 and emissions information
from the 2014 National Emission Inventory, South Dakota identified two
sources (GCC Dacotah and Pete Lien and Sons) in the State that may be
affecting visibility at Class I areas in South Dakota.\37\ South Dakota
also looked at WEP/AOI results,\38\ finding that these two sources'
relatively higher WEP values, compared to other sources for nitrates
and sulfates, further justified the selection of these sources for
four-factor analysis.\39\
---------------------------------------------------------------------------

\36\ South Dakota's 2022 SIP submission at 78.
\37\ Id.
\38\ WEP is a qualitative method of analyzing how pollutants
from particular sources may be transported to Class I areas.
\39\ South Dakota's 2022 SIP submission at 121.
---------------------------------------------------------------------------

Ultimately, the State selected these two sources to perform a four-
factor analysis (table 3).\40\
---------------------------------------------------------------------------

\40\ See WRAP_Threshold_Analysis.xlsm, available in the docket
for this action. Note that in the spreadsheet, Q/d summary data is
shown above a Q/d threshold of 10 tpy/km by default. Removing the
``AbvThresh_Q/d'' filter in the pivot table will present all Q/d
data for facilities within 400 km of a Class I Area. Removing the
``AbvThresh_Q/d'' filter in the pivot table will present all Q/d
data for facilities within 400 km of a Class I area.

Table 3--Facilities Screened in Using Q/d and Class I Area With Maximum Q/d
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Distance Updated Q/d value (tpy/km) Wind Cave NP Badlands NP
Class I area with (km) to -------------------------------------------------------------- maximum WEP maximum WEP
Facility name maximum Q/d Class I area state Class I value (NO3) value (NO3)
area NOX+SO2+PM10 NOX SO2 PM10
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
GCC Dacotah......................... Wind Cave NP........... South Dakota........... 51.62 22.63 16.02 5.89 0.72 172502.5 65883.83
Pete Lien and Sons.................. Wind Cave NP........... South Dakota........... 55.93 5.62 5.08 0.01 0.53 56732.86 22259.19
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

The State then requested four-factor analyses from these sources
for its review and consideration.\41\ South Dakota included the
facilities' four-factor analyses and other submissions in appendices to
its 2022 SIP submission. The State determined that the facilities'
submissions sufficiently evaluated potential emission reduction
measures.\42\ Section 3.3 of South Dakota's 2022 SIP submission
contains South Dakota's evaluation of the four statutory factors for
each source and South Dakota's determinations of whether source-
specific emission reduction measures are necessary to make reasonable
progress. In sections IV.C.1.i-iii. of this document, we summarize the
four-factor analyses for the two selected sources, as well as South
Dakota's reasons for concluding that no additional emission reduction
measures are necessary to make reasonable progress during the regional
haze second implementation period.
---------------------------------------------------------------------------

\41\ South Dakota's 2022 SIP submission at 121.
\42\ Id. at 134, 137.
---------------------------------------------------------------------------

a. GCC Dacotah \43\
---------------------------------------------------------------------------

\43\ This facility is addressed in South Dakota's 2022 SIP
submission, section 3.2.2.1. and Appendices B and C.
---------------------------------------------------------------------------

GCC Dacotah is a Portland cement manufacturing plant located in
Pennington County, South Dakota. GCC Dacotah now operates an indirect
fired dry kiln with a low-NO<INF>X</INF> burner known as the Kiln #6
system. This kiln system has a staged pre-combustion system, where
initial combustion occurs in a fuel-rich zone and secondary combustion
is carried out in a fuel-lean zone.\44\ South Dakota selected GCC
Dacotah for further evaluation because it exceeded the State's Q/d
threshold of 2 \45\ and because WRAP's WEP/AOI analysis indicated that
NO<INF>X</INF> and SO<INF>2</INF> emissions from this facility may
contribute to visibility impairment in Badlands National Park and Wind
Cave National Park.\46\ In its 2019 four-factor analysis, GCC Dacotah
reported that it made ``significant capital investments in recent years
to transition from two wet kilns to a single modern dry kiln and to
upgrade the dry kiln and its precalciner burner,'' which reduced net
emissions from the facility due to the retirement of the wet kilns and
the improved emissions performance of the upgraded dry kiln.\47\
Because GCC Dacotah reported that it had not achieved in practice its
final, steady state, full-scale production rates as of 2019,\48\ South
Dakota used projected actual emission rates used in the construction
permit for the facility as baseline emission rates. These rates are
shown below in table 4:
---------------------------------------------------------------------------

\44\ Id. at 131.
\45\ South Dakota's 2022 SIP submission at 78.
\46\ Id. at 121.
\47\ South Dakota's 2022 SIP submission, appendix C.
\48\ Id.

[[Page 20432]]

Table 4--GCC Dacotah Baseline Annual Emissions
------------------------------------------------------------------------
Baseline annual emissions (tons/yr)
Pollutant --------------------------------------
Total kiln system \1\ Kiln stack \2\
------------------------------------------------------------------------
SO2.............................. 734 560
NOX.............................. 1,975 1,394
------------------------------------------------------------------------
\1\ Total kiln system baseline emissions are the projected actual
emissions for the construction permit for the Kiln 6 upgrade, which
accounts for the kiln, alkali bypass, and coal mill stacks. The four-
factor analysis was limited to the kiln stack, which accounts for the
majority of emissions from GCC Dacotah.
\2\ Kiln baseline emissions are derived from the total kiln system
projected actual emissions and the proportion of the total emissions
associated with the kiln stack. The proportion of kiln stack versus
total kiln system is determined using continuous emission monitoring
system (CEMS) data.

South Dakota evaluated a range of controls for both SO<INF>2</INF>
and NO<INF>X</INF> emissions at GCC Dacotah, ultimately determining
that no additional measures are necessary at this source to achieve
reasonable progress during the regional haze second implementation
period.
South Dakota noted that GCC Dacotah already has inherent process
limestone/lime scrubbing via an in-line raw mill that removes
approximately 90% of the SO<INF>2</INF> that would otherwise be emitted
from the raw material.\49\ South Dakota evaluated a wet scrubber and a
semi-dry scrubber as potential additional SO<INF>2</INF> controls for
the facility. Applying interest rates ranging from 3% to 7%, South
Dakota calculated the cost per ton of SO<INF>2</INF> reduced as $5,453/
ton to $6,694/ton for a wet scrubber and $6,394/ton to $7,874/ton for a
semi-dry scrubber. South Dakota determined that neither scrubber was
cost-effective.\50\
---------------------------------------------------------------------------

\49\ South Dakota's 2022 SIP submission at 128 and appendix C.
\50\ South Dakota's 2022 SIP submission, appendix C.
---------------------------------------------------------------------------

GCC Dacotah currently operates a low-NO<INF>X</INF> burner on its
indirect fired kiln and uses good combustion practices (including the
use of uniform quality fuels) to control NO<INF>X</INF> emissions.\51\
In terms of additional NO<INF>X</INF> controls, South Dakota evaluated
flue gas recirculation (FGR) and found it to be technically infeasible,
explaining that FGR requires certain conditions (cooling the flame and
creating an oxygen-deficient atmosphere) that are not compatible with
the high flame temperatures and oxidizing atmosphere needed for
production of a quality clinker product.\52\ Lastly, South Dakota
evaluated selective catalytic reduction (SCR) at GCC Dacotah, finding
that SCR is not technically feasible for the facility. The State
maintained that SCR has seen extremely limited use in the cement kiln
industry and South Dakota notes that only one cement plant in the
country has installed SCR.\53\
---------------------------------------------------------------------------

\51\ South Dakota's 2022 SIP submission at 130, 132.
\52\ Id. at 131.
\53\ Id.
---------------------------------------------------------------------------

Finally, South Dakota evaluated selective noncatalytic reduction
(SNCR). In its 2019 four-factor analysis, GCC Dacotah found that SNCR
would cost $2,093/ton NO<INF>X</INF> removed.\54\ In an updated cost
analysis submitted in 2021, GCC Dacotah explained that its 2019 four-
factor analysis presented a ``study-level estimate'' of ``preliminary
cost calculations'' that relied on default inputs and assumptions.\55\
Using updated site-specific inputs, GCC Dacotah calculated the revised
cost of SNCR as $4,941/ton.\56\ Applying a range of interest rates to
GCC Dacotah's original (2019) cost calculations, and bolstered by the
GCC Dacotah's updated SNCR cost of $4,941/ton, South Dakota concluded
that adding SNCR at GCC Dacotah is not cost-effective.\57\
---------------------------------------------------------------------------

\54\ South Dakota's 2022 SIP Submission, appendix C, section
6.4.
\55\ South Dakota's 2022 SIP Submission, appendix B-2 (December
13, 2021 letter re: GCC Dacotah Cost Calculations for Regional
Haze).
\56\ Id.
\57\ South Dakota's 2022 SIP Submission, appendix B-1 at 3-4.
---------------------------------------------------------------------------

b. Pete Lien and Sons \58\
---------------------------------------------------------------------------

\58\ This facility is addressed in South Dakota's 2022 SIP
submission, section 3.3.2.2. and appendix D.
---------------------------------------------------------------------------

Pete Lien and Sons is a lime manufacturing plant located in Rapid
City, South Dakota. The facility is comprised of two direct-fired lime
kilns: Kiln 1 and Kiln 2.\59\ South Dakota selected Pete Lien and Sons
for further evaluation because emissions from the facility exceeded the
State's Q/d threshold of 2,\60\ and because WRAP's WEP/AOI analysis
indicated that the facility's NO<INF>X</INF> emissions may contribute
to visibility impairment in Badlands National Park and Wind Cave
National Park.\61\ South Dakota noted in its 2022 SIP submission that
Pete Lien and Sons had an SO<INF>2</INF>-specific Q/d value of less
than 0.1.\62\ As a result, South Dakota did not find it necessary to
evaluate additional SO<INF>2</INF> controls at Pete Lien and Sons.
---------------------------------------------------------------------------

\59\ South Dakota's 2022 SIP submission at 130.
\60\ Id. at 78.
\61\ Id. at 121.
\62\ South Dakota's 2022 SIP submission at 121.
---------------------------------------------------------------------------

South Dakota evaluated a range of controls for NO<INF>X</INF>
emissions, ultimately determining that no additional measures are
necessary at Pete Lien and Sons to achieve reasonable progress during
the second implementation period. To control NO<INF>X</INF> emissions,
Pete Lien and Sons currently utilizes kiln preheaters and ``good
combustion practices,'' which include a properly designed stone feeding
system, uniform stone feed material, and uniform quality fuels.\63\ The
environmental consulting firm SLR International Corporation, in its
four-factor analysis performed for Pete Lien and Sons, stated that the
preheater kiln ``preheats the incoming limestone, reducing fuel usage
and fuel generated emissions by approximately 30% compared to
conventional rotary kilns.'' \64\
---------------------------------------------------------------------------

\63\ Id. at 132.
\64\ South Dakota's 2022 SIP submission, appendix D.
---------------------------------------------------------------------------

In terms of additional NO<INF>X</INF> controls, South Dakota
considered FGR, staged combustion air, SNCR, and SCR.\65\ South Dakota
ultimately agreed with the source that FGR was technically infeasible,
stating that it has never been used in a lime kiln because the
conditions required for FGR are not compatible with production of a
high-quality lime product.\66\ Next, South Dakota considered staged
combustion, which it also rejected based on technical infeasibility on
the grounds that the conditions required for staged combustion are not
compatible with the production of a quality lime product.\67\
---------------------------------------------------------------------------

\65\ Id. at 130-133.
\66\ Id. at 131.
\67\ Id. at 131-132.
---------------------------------------------------------------------------

South Dakota also found that SCR is not technically feasible at
Pete Lien and Sons. The facility stated that there are no lime kilns in
the country that operate SCR because ``the exhaust gas characteristics
create significant chemical and physical problems for the facility.''
\68\ As a result, South Dakota

[[Page 20433]]

did not evaluate SCR at Pete Lien and Sons via the four statutory
factors.
---------------------------------------------------------------------------

\68\ South Dakota's 2022 SIP submission at 132.
---------------------------------------------------------------------------

South Dakota acknowledged that SNCR can be technically feasible at
lime kilns under the right conditions.\69\ In calculating the costs of
SNCR, South Dakota used a remaining useful life of 20 years, which
aligns with the recommendations in EPA's Control Cost Manual.\70\ South
Dakota noted potential non-air quality impacts of SNCR, including
decreased overall plant efficiency and an associated increase in
electrical usage, and determined that SNCR was likely infeasible at
Pete Lien and Sons.\71\ South Dakota nonetheless chose to evaluate SNCR
via the four factors and presented costs based on a range of interest
rates from 3-5%, finding that the cost-effectiveness of SNCR ranged
from approximately $34,000/ton to $58,000/ton.\72\ In comments on the
State's draft SIP, the National Park Service argued that errors in the
SNCR cost analysis, such as overly high urea costs and the inclusion of
lost kiln dust sales, led to inflated costs. Although South Dakota
maintained that the numbers used in the cost analysis were reasonable,
it provided a revised cost analysis incorporating the National Park
Service's suggestions.\73\ According to South Dakota's analysis, using
the default urea costs in the Control Cost Manual and removing the lost
kiln dust sales would drop SNCR costs to approximately $11,400/ton for
Kiln 1 and $17,400/ton for Kiln 2.\74\ South Dakota noted that it does
not consider these revised costs to be cost-effective for Pete Lien and
Sons.\75\
---------------------------------------------------------------------------

\69\ Id. at 132-133, 137-143.
\70\ EPA's Control Cost Manual, chapter 1: Selective
Noncatalytic Reduction, pg. 1-53 and 1-54. EPA's Control Cost Manual
provides detailed technical guidance on the estimation of capital
and annual costs for air pollution control devices for stationary
sources. The Control Cost Manual is commonly used by the EPA, state
and local officials, and industry parties that must comply with EPA
regulations or EPA permits. EPA has been updating the Control Cost
Manual under the authority of the Consolidated Appropriations Act of
2014. Public Law 113-76 (2014); 160 Cong. Rec. H475, H979 (January
15, 2014) (stating that the process for reviewing regional haze SIPs
``is well-served when EPA, States, and industry work collaboratively
to ensure that dispersion models are continually improved and
updated to ensure the most accurate predictions of visibility
impacts, as well as a uniform set of cost estimates''). Chapter
revisions undergo public notice and comment. Id.; 81 FR 65352
(September 22, 2016) (section 1, chapter 2 on cost estimation
concepts and methodology); 80 FR 33515 (June 12, 2015) (section 4,
chapter 1 on SNCR and section 4, chapter 2 on SCR).
\71\ South Dakota's 2022 SIP submission at 133.
\72\ Id.
\73\ South Dakota's 2022 SIP submission, appendix A-1, section
3.0, Response to Comment 14.
\74\ Id.
\75\ Id.
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c. Summary of South Dakota's Reasons for Concluding That No Additional
Emission Reduction Measures Are Necessary To Make Reasonable Progress
South Dakota provided several reasons for its conclusion that it is
not necessary to include additional controls for GCC Dacotah and Pete
Lien and Sons in the State's long-term strategy to make reasonable
progress toward the national visibility goal.\76\ South Dakota stated
that the regional haze program does not establish a ``specific
threshold or bright line'' on what measures to include in the long-term
strategy, and ``the rules allow the specific circumstances in each
state dictate how those four factors will inform that state's
decision.'' \77\
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\76\ South Dakota's 2022 SIP Submission at 138-143.
\77\ Id. at 139.
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For the costs of compliance, South Dakota determined that
additional NO<INF>X</INF> and SO<INF>2</INF> control measures are not
cost-effective, on a dollar per ton basis,\78\ at GCC Dacotah and Pete
Lien and Sons. Citing 40 CFR 51.308(f)(2)(iv)(E), (f)(3)(i), and
(f)(3)(ii)(A), South Dakota maintained that 2028 visibility projections
and the URP status of Class I areas may inform its determination of the
necessity of control measures and whether their cost is reasonable.
South Dakota stated that visibility projections for Badlands and Wind
Cave National Parks indicate these Class I areas are below the adjusted
URP. South Dakota explained that ``[i]f the Class I Areas are meeting
or projected to meet the natural background visibility goal, South
Dakota has met the requirements of the Regional Haze Rule.'' \79\ South
Dakota also stated that because reasonable progress was already being
achieved, requiring any additional controls would violate a state law
prohibiting the promulgation of a regulation that is more stringent
than corresponding Federal law.
---------------------------------------------------------------------------

\78\ In evaluating the cost-effectiveness of controls, South
Dakota cited approximate costs of $1,700/ton NO<INF>X</INF> reduced
(for SNCR) and $6,500/ton SO<INF>2</INF> reduced (for semi-dry and
wet scrubbers) at GCC Dacotah, and $34,500/ton NO<INF>X</INF>
reduced (for SNCR) at Pete Lien and Sons. Id. at 134-38, 140. The
State also noted that the revised cost estimate that GCC Dacotah
calculated for SNCR ($4,941/ton NO<INF>X</INF> reduced) bolstered
its decision that SNCR was not cost-effective. South Dakota's 2022
SIP Submission, appendix B-1 at 3-4.
\79\ South Dakota's 2022 SIP Submission at 140.
---------------------------------------------------------------------------

South Dakota further explained that it would ``consider a higher $
per ton cost as reasonable'' if the State were not in attainment for
the National Ambient Air Quality Standards (NAAQS), but noted that it
is currently meeting the NAAQS.\80\ Similarly, South Dakota considered
the impacts of its sources on visibility at Class I areas, stating that
it ``would consider a higher $ per ton cost as reasonable if South
Dakota's facilities are a major contributor to visibility impacts
compared to if they are a minor source of impacts.'' \81\ The State
noted that even if all pollution sources in South Dakota were
eliminated, in-state Class I areas would achieve only a 1% improvement
in visibility, while out-of-state Class I areas would achieve 0%
improvement. South Dakota concluded that under these circumstances, it
did not consider additional controls at GCC Dacotah and Pete Lien and
Sons to be cost-effective.
---------------------------------------------------------------------------

\80\ Id. at 141.
\81\ Id.
---------------------------------------------------------------------------

For the time necessary for compliance, South Dakota stated that
``Wind Cave National Park is projected to meet the adjusted national
background goal in 2064 by 2028 and Badlands National Park will be
about 70% of the goal by 2028 and the potential timelines for
installation of the control systems.'' \82\ It concluded that, as a
result, additional controls are not necessary to meet regional haze
requirements.
---------------------------------------------------------------------------

\82\ Id. at 142.
---------------------------------------------------------------------------

For the energy and non-air quality impacts of compliance, South
Dakota considered additional increases in electricity demand associated
with the operation of pollution control systems, as well as safety
concerns with the transport and storage of ammonia (which is used as a
reagent in SNCR systems). The State also expressed concern about the
impacts of ammonia slip, which refers to emissions of unreacted ammonia
that result from incomplete reaction of NO<INF>X</INF> and the reagent
used in SNCR systems. The State maintained that ammonia slip may cause
particulate matter concentrations to increase in the Rapid City area,
and that it ``does not consider the risk to Rapid City's attainment of
the particulate matter National Ambient Air Quality standard is
justified.'' \83\
---------------------------------------------------------------------------

\83\ Id. at 142-43.
---------------------------------------------------------------------------

Finally, in its consideration of remaining useful life, South
Dakota noted that GCC Dacotah and Pete Lien and Sons are expected to
operate beyond the 20-year useful life of the control measures that
were evaluated through four-factor analysis. However, South Dakota did
not cite this factor as a reason not to require additional controls.
The EPA's evaluation of South Dakota's rationales for not including any
additional emission reduction measures in its long-term strategy is
contained in section IV.C.2.iii. of this document.

[[Page 20434]]

2. The EPA's Evaluation of South Dakota's Long-Term Strategy
In section IV.C.2. of this document, we evaluate South Dakota's
determinations of the measures necessary to make reasonable progress
(i.e., its long-term strategy) against the requirements of the CAA and
RHR for the second implementation period of the regional haze program.
Considering the four statutory factors and the projected 2028
visibility conditions for Class I areas both in South Dakota and those
influenced by emissions from South Dakota sources, which are all below
the URP, the EPA finds South Dakota reasonably concluded that no
additional measures for GCC Dacotah and Pete Lien and Sons are
necessary to make reasonable progress in the second planning period. As
detailed further below, the EPA proposes to approve South Dakota's
long-term strategy under 40 CFR 51.308(f)(2).
In this proposed action, the EPA notes that it is the Agency's
policy, as announced in the EPA's recent proposed approval of the West
Virginia Regional Haze SIP,\84\ that where visibility conditions for a
Class I area impacted by a State are below the URP and the State has
evaluated potential control measures and considered the four statutory
factors, the State will have presumptively demonstrated reasonable
progress for the second planning period for that area. The EPA requests
comment on this updated policy. The EPA acknowledges that this proposed
action reflects a change in policy from current guidance as to how the
URP should be used in the evaluation of regional haze second planning
period SIPs. The EPA has the discretion and authority to change policy.
In FCC v. Fox Television Stations, Inc., the U.S. Supreme Court plainly
stated that an agency is free to change a prior policy and ``need not
demonstrate . . . that the reasons for the new policy are better than
the reasons for the old one; it suffices that the new policy is
permissible under the statute, that there are good reasons for it, and
that the agency believes it to be better.'' 566 U.S. 502, 515 (2009)
(referencing Motor Vehicle Mfrs. Ass'n of United States, Inc. v. State
Farm Mut. Auto. Ins. Co., 463 U.S. 29 (1983)). See also Perez v.
Mortgage Bankers Assn., 135 S. Ct. 1199 (2015). However, the EPA
believes that this policy aligns with the purpose of the statute and
RHR, which is achieving ``reasonable'' progress, not maximal progress,
toward Congress' natural visibility goal.
---------------------------------------------------------------------------

\84\ 90 FR 16478, 16483 (April 18, 2025).
---------------------------------------------------------------------------

In developing the regulations required by CAA section 169A(b), the
EPA established the concept of the URP for each Class I area. As
discussed above, for each Class I area, there is a regulatory
requirement to compare the projected visibility impairment (represented
by the reasonable progress goal, or ``RPG'') at the end of each
planning period to the URP (e.g., in 2028 for the second planning
period).\85\ In the 2017 RHR Revisions, the EPA addressed the role of
the URP as it relates to a state's development of its second planning
period SIP.\86\ Specifically, in response to comments suggesting that
the URP should be considered a ``safe harbor'' and relieve states of
any obligation to consider the four statutory factors, the EPA
explained that the URP was not intended to be such a safe harbor.\87\
Some commenters stated a desire for corresponding rule text dealing
with situations where RPGs are equal to (``on'') or better than
(``below'') the URP or glidepath. Several commenters stated that the
URP or glidepath should be a ``safe harbor,'' opining that states
should be permitted to analyze whether projected visibility conditions
for the end of the implementation period will be on or below the
glidepath based on on-the-books or on-the-way control measures, and
that in such cases a four-factor analysis should not be required.\88\
Other 2017 RHR comments indicated a similar approach, such as ``a
somewhat narrower entrance to a `safe harbor,' '' by suggesting that if
current visibility conditions are already below the end-of-planning-
period point on the URP line, a four-factor analysis should not be
required.\89\ The EPA stated in its response that we do not agree with
either of these recommendations. The CAA requires that each SIP
revision contain long-term strategies for making reasonable progress,
and that in determining reasonable progress states must consider the
four statutory factors. Treating the URP as a safe harbor would be
inconsistent with the statutory requirement that states assess the
potential to make further reasonable progress towards natural
visibility goal in every implementation period.\90\
---------------------------------------------------------------------------

\85\ 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 (January 10,
2017).
\86\ 82 FR 3078 (January 10, 2017).
\87\ 82 FR 3099 (January 10, 2017).
\88\ Id.
\89\ Id.
\90\ Id.
---------------------------------------------------------------------------

The 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 planning period for that area.
Indeed, we believe 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 South Dakota's SIP
and as further detailed in the paragraphs that follow, the EPA agrees
with South Dakota's determination that, for the second planning period,
no additional measures are necessary to achieve reasonable progress
towards natural visibility at Class I areas impacted by emissions from
South Dakota sources.
The SIP submittal included evaluations for two emissions sources,
including consideration of the four statutory factors for GCC Dacotah
and Pete Lien and Sons. Based on these evaluations and analyses, the
State determined that no additional measures were necessary for
reasonable progress. In reaching this determination, South Dakota also
considered the relatively small impact of South Dakota emission sources
on all Class I areas, and the emission reductions and visibility
improvements that have already occurred in the second planning period
in South Dakota and nearby Class I areas. Because the State considered
the four statutory factors in the assessment of the potential for
additional controls to make reasonable progress and the projected 2028
visibility conditions for Class I areas influenced by emissions from
South Dakota sources are all below the URP, the EPA finds that South
Dakota has demonstrated that it has made reasonable progress towards
the national visibility goal for the second planning period. Therefore,
we are proposing to approve South Dakota's SIP submittal as meeting the
CAA and regulatory requirement to make reasonable progress towards the
national visibility goal.
a. GCC Dacotah
South Dakota evaluated control measures at GCC Dacotah, considered
the four statutory factors, and rejected

[[Page 20435]]

additional NO<INF>X</INF> and SO<INF>2</INF> controls based on cost
(approximately $4,900/ton NO<INF>X</INF> reduced for SNCR \91\ and
approximately $5,400-$7,900/ton SO<INF>2</INF> reduced for semi-dry and
wet scrubbers). South Dakota cites the limited magnitude of visibility
impacts attributable to South Dakota's non-EGU sector sources. A review
of WRAP Technical Support System (TSS) data shows that all emissions
from the entire South Dakota non-EGU sector (which includes GCC
Dacotah) represent only 0.66% and 0.37% of total anthropogenic (nitrate
and sulfate combined) visibility impacts at Wind Cave National Park and
Badlands National Park, respectively.\92\
---------------------------------------------------------------------------

\91\ The EPA is basing its evaluation on GCC Dacotah's updated
SNCR cost estimate of $4,941/ton, not on the source's initial cost
estimate of $2,093/ton or on South Dakota's determination that
approximately $1,700/ton for SNCR would not be cost-effective.
\92\ ``TSS XY Chart--Product #XMTP_SASB_LUCS.'' WRAP Technical
Support System (TSS); CSU and the Cooperative Institute for Research
in the Atmosphere (CIRA), 30 Dec 2024.
---------------------------------------------------------------------------

In terms of evaluation of NO<INF>X</INF> controls, South Dakota
reasonably decided not to evaluate FGR and SCR on the basis of
technical infeasibility. South Dakota adequately explained that FGR
requires certain conditions (cooling the flame and creating an oxygen-
deficient atmosphere) that are not compatible with the high flame
temperatures and oxidizing atmosphere needed for production of a
quality clinker product at GCC Dacotah.\93\ \94\ South Dakota noted
that SCR has seen extremely limited use in the cement kiln industry
because high-dust and semi-dust SCR systems rely on site-specific
limits.\95\ As South Dakota stated, SCR has seen extremely limited use
in cement kilns, largely due to concerns about catalyst inactivation or
catalyst plugging and fouling associated with sticky deposits in the
preheater exhaust gas at the temperatures necessary for SCR operation.
Based on the State's concerns with high dust levels, catalyst fouling,
plugging, or deactivation, as well as other SCR-related issues, and the
limited use of SCR at cement kilns in the U.S., it is reasonable for
South Dakota to determine that SCR is not technically feasible at GCC
Dacotah.
---------------------------------------------------------------------------

\93\ South Dakota's 2022 SIP submission at 131.
\94\ Assessment of NO<INF>X</INF> Emissions Reduction Strategies
for Cement Kilns--Ellis County: Final Report. Prepared by ERG Inc.
for Texas Commission on Environmental Quality (TCEQ). July 14, 2006.
Accessed via <a href="https://downloads.regulations.gov/EPA-R09-OAR-2021-0923-0005/attachment_3.pdf">https://downloads.regulations.gov/EPA-R09-OAR-2021-0923-0005/attachment_3.pdf</a>.
\95\ South Dakota's 2022 SIP submission at 132.
---------------------------------------------------------------------------

In addition, South Dakota's evaluated SNCR under the four-factors,
and determined that SNCR is not necessary to make reasonable progress.
GCC Dacotah's updated cost estimate, which used site-specific data
input values reflective of November 2021 operations, showed that SNCR
would cost $4,941/ton NO<INF>X</INF> removed. To calculate costs of
compliance, GCC used the EPA's SNCR Cost Calculation Spreadsheet,\96\
which includes default values that can be adjusted by individual users
to reflect site-specific information.
---------------------------------------------------------------------------

\96\ The EPA's SNCR Cost Calculation Spreadsheets are available
in the docket for this action and can be downloaded from <a href="https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution">https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution</a>.
---------------------------------------------------------------------------

The electricity cost ($0.08/kW-hr) and fuel cost ($2.87/MMBtu)
cited by GCC are in the range of the default values assumed in the 2019
version of the EPA's SNCR Cost Calculation Spreadsheet ($0.0676/kW-hr
and $2.40/MMBtu, respectively).\97\ However, the ammonia reagent cost
cited by GCC ($1.67/gal) is substantially higher than default values
assumed in the cost-calculation spreadsheet ($0.293/gal).\98\ As noted
in a May 2022 report from the EIA, U.S. ammonia prices rose
significantly (by a factor of six) from 2020-2022 due to an increase in
natural gas prices.\99\ The ammonia cost cited by GCC Dacotah ($1.67/
gal) in November 2021 would amount to around $650 per short ton,\100\
which is in line with the cost that would be expected at that time
based on both Energy Information Administration (EIA) \101\ and United
States Geological Services (USGS) \102\ reports. In calculating the
cost of compliance of installing SNCR, GCC assumed a 19% ammonia
concentration,\103\ which is in line with the concentration assumed in
the EPA's Control Cost Manual.\104\ GCC also used a 30% assumed control
efficiency rate in its updated cost analysis. Because the control
efficiency assumed by GCC Dacotah falls within the range of control
efficiencies demonstrated by SNCR systems that have been successfully
installed on other cement kilns,\105\ GCC's use of an assumed 30%
control efficiency is reasonable in this instance. Consequently, we
find that the record adequately supports South Dakota's consideration
of costs of compliance for GCC Dacotah.
---------------------------------------------------------------------------

\97\ Electricity cost: U.S. Energy Information Administration.
Electric Power Monthly. Table 5.6.A Published December 2017.
Available at: <a href="https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a">https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_5_6_a</a>; Fuel cost: U.S. Energy
Information Administration. Electric Power Annual 2016. Table 7.4.
Published December 2017. Available at: <a href="https://www.eia.gov/electricity/annual/pdf/epa.pdf">https://www.eia.gov/electricity/annual/pdf/epa.pdf</a>.
\98\ U.S. Geological Survey, Minerals Commodity Summaries,
January 2017. Available at: <a href="https://minerals.usgs.gov/minerals/pubs/commodity/nitrogen/mcs-2017-nitro.pdf">https://minerals.usgs.gov/minerals/pubs/commodity/nitrogen/mcs-2017-nitro.pdf</a>.
\99\ ``U.S. ammonia prices rise in response to higher
international natural gas prices.'' EIA, May 10, 2022. Accessed via
<a href="https://www.eia.gov/todayinenergy/detail.php?id=52358">https://www.eia.gov/todayinenergy/detail.php?id=52358</a>.
\100\ ``Anhydrous Ammonia.'' Purdue University College of
Agriculture, June 2021. Accessed via <a href="https://ag.purdue.edu/department/extension/ppp/resources/ppp-publications/ppp-140.html">https://ag.purdue.edu/department/extension/ppp/resources/ppp-publications/ppp-140.html</a>.
Since a gallon of ammonia weighs 5.14 pounds, one short ton (2000
pounds) of ammonia at $1.67 per gallon equates to ~$649.81.
\101\ ``U.S. ammonia prices rise in response to higher
international natural gas prices.'' EIA, May 10, 2022. Accessed via
<a href="https://www.eia.gov/todayinenergy/detail.php?id=52358">https://www.eia.gov/todayinenergy/detail.php?id=52358</a>.
\102\ A 2022 Mineral Commodity Summary from the United States
Geological Survey (USGS) shows that the price of ammonia rose
sharply to $603 per short ton in October 2021, while the average
cost of ammonia in 2021 was $510 per short ton. ``Mineral Commodity
Summary--Nitrogen (Fixed) Ammonia.'' USGS, January 2022. Accessed
via <a href="https://pubs.usgs.gov/periodicals/mcs2022/mcs2022-nitrogen.pdf">https://pubs.usgs.gov/periodicals/mcs2022/mcs2022-nitrogen.pdf</a>.
\103\ South Dakota's 2022 SIP submission, appendix B-2.
\104\ EPA's Control Cost Manual--chapter 1: Selective
Noncatalytic Reduction at 1-12 (``most U.S. cement plants use a
solution of 19-20% aqueous ammonia reagent'').
\105\ Technical Support Document (TSD)--Oldcastle Trident
Federal Implementation Plan Revision, March 8, 2017. See Attachment
1 to the TSD, Summary of SNCR Performance Data for Long Cement
Kilns.
---------------------------------------------------------------------------

South Dakota also evaluated the other three statutory factors for
GCC Dacotah. Time necessary for compliance was considered and South
Dakota did not eliminate any control options from consideration as a
result of time necessary for compliance.\106\ South Dakota raised
concerns about certain energy and non-air quality impacts, but did not
eliminate any controls from consideration solely as a result of these
impacts.\107\ Lastly, South Dakota appropriately considered remaining
useful life.\108\ South Dakota concluded that no additional measures at
GCC Dacotah are necessary to make reasonable progress for the second
planning period. Because South Dakota considered the four statutory
factors for GCC Dacotah and visibility conditions at all Class I areas
to which South Dakota contributes are below the URP, the EPA finds that
South Dakota has demonstrated that it has made reasonable progress for
the second planning period without any additional measures for GCC
Dacotah.
---------------------------------------------------------------------------

\106\ South Dakota's 2022 SIP submission at 142.
\107\ Id. at 142-143.
\108\ Id.
---------------------------------------------------------------------------

b. Pete Lien and Sons
Similarly, and as detailed below, South Dakota determined that no
additional emission reduction measures are necessary at Pete Lien and
Sons to make reasonable progress during the regional haze second
implementation period. South Dakota rejected kiln fuel changes, low-
NO<INF>X</INF> burners, staged combustion, FGR, and SCR on the basis

[[Page 20436]]

of technical infeasibility or unavailability. South Dakota adequately
explained that using alternative kiln fuels is not an available method
of NO<INF>X</INF> control because the fuels needed for the kilns at
Pete Lien and Sons must have sufficient heat content and be readily
available in significant quantities so as not to disrupt continuous
production, and because the solid fuels currently used in the kiln
already produce lower NO<INF>X</INF> emissions than alternative gaseous
fuels.\109\ South Dakota adequately explained that low-NO<INF>X</INF>
burners are technically infeasible at this facility because Pete Lien
and Sons operates direct-fire kilns and low-NO<INF>X</INF> burners
require an indirect-fired kiln for operation.\110\ Similarly, South
Dakota adequately explained that staged combustion is not technically
feasible for Pete Lien and Sons because lime kilns do not combust in
two stages. Our review of the Reasonably Available Control Technology/
Best Available Control Technology/Lowest Achievable Emission Rate
(RACT/BACT/LAER) Clearinghouse for lime kilns that was provided in the
appendices to South Dakota's 2022 SIP submission shows that there are
no lime kilns that utilize staged combustion.\111\ As for FGR, our
review of the RACT/BACT/LAER Clearinghouse for lime kilns in South
Dakota's 2022 SIP submission similarly shows that there are no lime
kilns that operate FGR and therefore it is not a technically feasible
control option at Pete Lien and Sons.\112\ Finally, South Dakota
provided similar information that no lime kilns have successfully
installed and operated SCR; therefore, South Dakota determined that SCR
is not feasible at Pete Lien and Sons.\113\
---------------------------------------------------------------------------

\109\ South Dakota's regional haze SIP submission at 130.
\110\ Id. at 130-131.
\111\ South Dakota's 2022 SIP submission, appendix D.
\112\ Id.
\113\ Id.
---------------------------------------------------------------------------

South Dakota rejected SNCR as a potential emission reduction
measure for Pete Lien and Sons due to the high costs of
compliance.\114\ As noted in section C.1.b. of this document, South
Dakota presented costs based on a range of interest rates from 3-5%,
finding that the cost-effectiveness of SNCR ranged from approximately
$34,000/ton to $58,000/ton NO<INF>X</INF> reduced; \115\ using the
default urea costs and removing the lost kiln dust sales, as requested
in comments from the National Park Service, would drop costs to
approximately $11,400/ton-$17,400/ton for Kilns 1 and 2,
respectively.\116\ South Dakota's also evaluated the other three
statutory factors for Pete Lien and Sons. Time necessary for compliance
was considered and South Dakota did not eliminate any control options
from consideration as a result of time necessary for compliance.\117\
South Dakota raised concerns about certain energy and non-air quality
impacts, but did not eliminate any controls from consideration solely
as a result of these impacts.\118\ Lastly, South Dakota's considered
remaining useful life.\119\ South Dakota concluded that no additional
measures at Pete Lien and Sons are necessary to make reasonable
progress for the second planning period. Because South Dakota
considered the four statutory factors for Pete Lien and Sons and
visibility conditions at all Class I areas to which South Dakota
contributes are below the URP, the EPA finds that South Dakota has
demonstrated that it has made reasonable progress for the second
planning period without any additional measures for Pete Lien and Sons.
---------------------------------------------------------------------------

\114\ As with GCC Dacotah and as further detailed in section
IV.C.2.iii. of this document, we find that South Dakota's
conclusions regarding certain other factors, including the
environmental and non-air quality impacts of compliance, do not
support its rejection of SNCR for Pete Lien and Sons. Nonetheless,
we conclude that South Dakota's decision is justified based on the
costs of compliance.
\115\ South Dakota's 2022 SIP submission at 137-138.
\116\ Id.
\117\ South Dakota's 2022 SIP submission at 142.
\118\ Id. at 142-143.
\119\ Id.
---------------------------------------------------------------------------

c. Other Long-Term Strategy Requirements (40 CFR 51.308(f)(2)(ii)
Through (iv))
States must meet the additional requirements specified in 40 CFR
51.308(f)(2)(ii) through (iv) when developing their long-term
strategies. Section 51.308(f)(2)(ii) requires states to consult with
other states that have emissions that are reasonably anticipated to
contribute to visibility impairment in Class I areas to develop
coordinated emission management strategies. Section 6.2 of South
Dakota's 2022 SIP submission describe the State's consultation with
other states throughout the development of its regional haze plan.
Section 51.308(f)(2)(iii) requires states to document the technical
basis, including modeling, monitoring, costs, 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 area it impacts. Sections 2, 3, 4,
and 5 of South Dakota's 2022 SIP submission describe the technical
information on which the State relied. The State relied on WRAP
technical information, modeling, and analysis to support development of
its long-term strategy.\120\
---------------------------------------------------------------------------

\120\ South Dakota's 2022 SIP submission at 46-177.
---------------------------------------------------------------------------

Section 51.308(f)(2)(iv) specifies five additional factors states
must consider in developing their long-term strategies. The five
additional factors are: emission reductions due to ongoing air
pollution control programs, including measures to address reasonably
attributable visibility impairment; measures to mitigate the impacts of
construction activities; source retirement and replacement schedules;
basic smoke management practices for prescribed fire used for
agricultural and wildland vegetation management purposes and smoke
management programs; and 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. Section 3.2.5 of South
Dakota's 2022 SIP submission describes each of the five additional
factors.\121\ After reviewing South Dakota's 2022 SIP chapters
addressing 40 CFR 51.308(f)(2)(ii) through (iv), the EPA finds that
South Dakota has satisfied the long-term strategy requirements of 40
CFR 51.308(f)(2)(ii) through (iv).
---------------------------------------------------------------------------

\121\ Id. at 122-126.
---------------------------------------------------------------------------

D. Reasonable Progress Goals

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) in states' long-term strategies, as well as
implementation of other CAA requirements.
After establishing its long-term strategy, South Dakota developed
reasonable progress goals for each Class I Area for the 20% most
impaired days and 20% clearest days based on the results of 2028 WRAP
modeling (table 5).\122\
---------------------------------------------------------------------------

\122\ Id. at 166.

[[Page 20437]]

Table 5--Reasonable Progress Goals for the 20% Most Impaired Days and 20% Clearest Days for South Dakota's Class
I Areas
----------------------------------------------------------------------------------------------------------------
20% Most impaired days 20% Clearest days
------------------------------------------------------------------
2028
Class I area Average Uniform 2028 Average 2028
baseline rate of Reasonable baseline Reasonable
conditions progress progress conditions progress
(2000-2004) \1\ goal \2\ (2000-2004) goal
----------------------------------------------------------------------------------------------------------------
Deciviews
----------------------------------------------------------------------------------------------------------------
Badlands National Park....................... 15 13 11.53 6.9 5.1
Wind Cave National Park...................... 13.1 11.9 9.76 5.1 3.4
----------------------------------------------------------------------------------------------------------------
\1\ Based on the adjusted glidepath.
\2\ Based on WRAP 2028OTBa2.

The reasonable progress goals are based on South Dakota's long-term
strategy, the long-term strategy of other states that may affect Class
I areas in South Dakota, and other CAA requirements. Per 40 CFR
51.308(f)(3)(iv), the EPA must evaluate the demonstrations the State
developed pursuant to 40 CFR 51.308(f)(2) to determine whether the
State's reasonable progress goals for visibility improvement provide
for reasonable progress towards natural visibility conditions. As
previously explained in sections IV.C.2., we are proposing to approve
South Dakota's long-term strategy for meeting the requirements of 40
CFR 51.308(f)(2). Specifically, we find that South Dakota's reasonable
progress goals provide for an improvement in visibility for the most-
impaired days since the baseline period and ensure no degradation in
visibility on the clearest days since the baseline period.\123\
Therefore, we propose to approve South Dakota's reasonable progress
goals under 40 CFR 51.308(f)(3).
---------------------------------------------------------------------------

\123\ Id. at 146-176.
---------------------------------------------------------------------------

E. Reasonably Attributable Visibility Impairment (RAVI)

The RHR 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,'' \124\ also known as RAVI. 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 RAVI, the state must include
in its SIP revision for the second implementation period an appropriate
strategy for evaluating such impairment. The EPA has not advised the
State to that effect; nor did the State indicate that FLMs for Badlands
National Park and Wind Cave National Park identified any RAVI from
South Dakota sources. For this reason, the EPA proposes to approve the
portions of South Dakota's 2022 SIP submission relating to 40 CFR
51.308(f)(4).
---------------------------------------------------------------------------

\124\ The EPA's visibility protection regulations define
``reasonably attributable visibility impairment'' as ``visibility
impairment that is caused by the emission of air pollutants from
one, or a small number of sources.'' 40 CFR 51.301.
---------------------------------------------------------------------------

F. Monitoring Strategy and Other State 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 section 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.
Under 40 CFR 51.308(f)(6)(i), States must provide for the
establishment of 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. For states with Class I areas (including South Dakota), Sec.
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. 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.
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. Section
51.308(f)(6)(v) also requires states to include estimates of future
projected emissions. Finally, 40 CFR 51.308(f)(6)(vi) requires the SIP
to provide for any other elements, including reporting, recordkeeping,
and other measures, that are necessary for states to assess and report
on visibility.
South Dakota describes its participation in the IMPROVE network,
which is comprised of 110 monitoring sites across the Nation, two of
which are in South Dakota. The State relied on the IMPROVE monitoring
network to assess visibility at Class I areas across South Dakota \125\
and considered the two monitoring sites, BADL1 and WICA1, to be
adequate for assessing reasonable progress goals at the State's two
Class I areas.\126\ Using the monitoring data procedures described in
its 2022 SIP submission along with other technical information supplied
by WRAP,\127\ \128\ the State determined the contribution of in-State
emissions to Class I areas inside and outside South Dakota.\129\ In
addition, the State also provided a statewide inventory of emissions
that are reasonably anticipated to cause or contribute to visibility
impairment in Class I areas; the State relied primarily on 2019 data
but also estimated future projected emissions for 2028.\130\
---------------------------------------------------------------------------

\125\ South Dakota 2022 SIP submission at 177-178.
\126\ Id. at 21-23 and 177-178.
\127\ Id. at 179-180.
\128\ South Dakota relied on the WRAP Technical Support System
(TSS) ``Analysis and Planning'' section to determine baseline,
natural, and current conditions for Class I areas in South Dakota.
<a href="https://views.cira.colostate.edu/tssv2/">https://views.cira.colostate.edu/tssv2/</a>.
\129\ South Dakota 2022 SIP submission at 181-188.
\130\ Id. at 181-182.
---------------------------------------------------------------------------

The EPA finds that South Dakota has met the requirements of 40 CFR
51.308(f)(6), including through its continued participation in the

[[Page 20438]]

IMPROVE network and WRAP RPO and its ongoing compliance with the Air
Emissions Reporting Requirements (AERR). There is no indication that
further SIP elements are necessary at this time for South Dakota to
assess and report on visibility. Therefore, the EPA proposes to approve
the monitoring strategy and other state implementation plan elements of
South Dakota's 2022 SIP submission as meeting the requirements of 40
CFR 51.308(f)(6).

G. 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 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 that 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.
In its 2022 SIP submission, South Dakota included the elements of
the periodic progress report specified in 40 CFR 51.308(f)(5) and
(g)(1) through (5). South Dakota summarized the facility improvements
made during and after the first implementation period, including
emission control measures installed and emission reductions achieved by
the Big Stone Power Plant.\131\ In addition, the State summarized the
implementation status of ongoing air pollution control rules for
fugitive emissions and requirements for new major sources and
modifications to major sources to conduct a visibility analysis.\132\
The State also provided emissions inventories for NO<INF>X</INF>,
SO<INF>2</INF>, PM, and CO that identify the type of source, activity,
and pollutant representing 2014 actual emissions and 2014-2018
representative baseline emissions.\133\
---------------------------------------------------------------------------

\131\ South Dakota 2022 SIP submission at 198-199.
\132\ Id. at 122-125.
\133\ Id. at 181-189.
---------------------------------------------------------------------------

Visibility conditions (in deciviews) are reported in South Dakota's
2022 SIP submission for the most impaired and clearest days. Visibility
conditions are expressed in terms of 5-year averages for the baseline
period (2000-2004), and current period (2014-2018), as well as the
progress made since the baseline period (2000-2004--2014-2018) and
during the last implementation period (2008-2012--2014-2018) for each
Class I area.\134\ South Dakota also provided an assessment and
discussion of the significant changes in anthropogenic emissions since
the first implementation period.\135\
---------------------------------------------------------------------------

\134\ Id. at 203-216.
\135\ Id. at 214-216.
---------------------------------------------------------------------------

Because South Dakota's 2022 SIP submission addresses the
requirements of 40 CFR 51.308(g)(1) through (5), the EPA finds that
South Dakota has met the progress report requirements of 40 CFR
51.308(f)(5). Therefore, we propose to approve South Dakota's 2022 SIP
submission as meeting the requirements of 40 CFR 51.308(f)(5) and (g)
for periodic progress reports.

H. 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, the 40 CFR 51.308(i)(2) 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 lists 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.
South Dakota's 2022 SIP submission summarizes the State's
consultation and coordination with the FLMs. South Dakota consulted and
coordinated with the FLMs during the development of its regional haze
SIP through WRAP participation and direct FLM engagement.\136\ On
September 15, 2021, South Dakota submitted the State's draft regional
haze plan to the FLMs for consultation and received comments
thereafter. South Dakota subsequently analyzed the FLMs comments,
modified the draft regional haze plan, summarized and responded to each
comment, and included the information in an appendix to its SIP
submission which was made available for public comment.\137\ The State
explained how it is committed to coordinating and consulting with the
FLMs during the development of future progress reports and SIP
submissions, as well as during the implementation of programs having
the potential to contribute to visibility impairment in Class I
areas.\138\
---------------------------------------------------------------------------

\136\ Id. at 189-91.
\137\ South Dakota 2022 SIP submission at 190-191, appendix A.
\138\ Id. at 191-193.
---------------------------------------------------------------------------

Compliance with 40 CFR 51.308(i) is dependent on compliance with 40
CFR 51.308(f)(2)'s long-term strategy provisions and 40 CFR
51.308(f)(3)'s reasonable progress goals provisions. Because the EPA is
proposing to approve South Dakota's long-term strategy under 40 CFR
51.308(f)(2) and the reasonable progress goals under 40 CFR
51.308(f)(3), the EPA is also proposing to approve the State's FLM
consultation under 40 CFR 51.308(i). South Dakota took administrative
steps

[[Page 20439]]

to provide the FLMs the opportunity to review and provide feedback on
the State's draft regional haze plan. Therefore, the EPA proposes to
approve the FLM consultation component of South Dakota's SIP
submission, which meets the requirements of 40 CFR 51.308(i), as
outlined in this section.

V. Proposed Action

The EPA is proposing approval of South Dakota's 2022 SIP submission
addressing the requirements of the second implementation period of the
RHR. Specifically, the EPA is proposing approval of South Dakota's 2022
SIP submission relating to 40 CFR 51.308(f)(1): calculations of
baseline, current, and natural visibility conditions, progress to date,
and the uniform rate of progress; 40 CFR 51.308(f)(2): long-term
strategy; 40 CFR 51.308(f)(3): reasonable progress goals; 40 CFR
51.308(f)(4): reasonably attributable visibility impairment; 40 CFR
51.308(f)(5) and (g): progress report requirements; 40 CFR
51.308(f)(6): monitoring strategy and other implementation plan
requirements; and 40 CFR 51.308(i): FLM consultation.

VI. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, EPA's role is to approve state choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely proposes to approve state law as meeting Federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this action:
<bullet> 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);
<bullet> Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because State Implementation Plan approvals under the
CAA are exempt from review under Executive Order 12866;
<bullet> Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
<bullet> 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.);
<bullet> 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);
<bullet> Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
<bullet> Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it approves a state program;
<bullet> Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
<bullet> Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where EPA or an Indian Tribe has
demonstrated that a Tribe has jurisdiction. In those areas of Indian
country, the rule does not have Tribal implications and will not impose
substantial direct costs on Tribal governments or preempt Tribal law as
specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

List of Subjects in 40 CFR Part 52

Environmental protection, Air pollution control, Carbon monoxide,
Greenhouse gases, Incorporation by reference, Intergovernmental
relations, Lead, Nitrogen dioxide, Ozone, Particulate matter, Reporting
and recordkeeping requirements, Sulfur oxides, Volatile organic
compounds.

Dated: April 28, 2025.
Cyrus M. Western,
Regional Administrator, Region 8.

For the reasons stated in the preamble, the Environmental
Protection Agency is proposing to amend 40 CFR part 52 as follows:

PART 52--APPROVAL AND PROMULGATION OF IMPLEMENTATION PLANS

0
1. The authority citation for part 52 continues to read as follows:

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

Subpart QQ--South Dakota

0
2. In Sec. 52.2170, the table in paragraph (e) is amended by adding
the entry ``XXVIII. South Dakota Regional Haze State Implementation
Plan'' at the end of the table to read as follows:

Sec. 52.2170 Identification of plan.

* * * * *
(e) * * *

----------------------------------------------------------------------------------------------------------------
State
Rule title effective EPA effective date Final rule citation, Comments
date date
----------------------------------------------------------------------------------------------------------------

* * * * * * *
XXVIII. South Dakota Regional Haze 4/21/2022 [date 30 days after date 90 FR [Federal Register
State Implementation Plan. of publication of the page where the
final rule in the document begins of the
Federal Register]. final rule], [date of
publication of the
final rule in the
Federal Register].
----------------------------------------------------------------------------------------------------------------

[FR Doc. 2025-08072 Filed 5-13-25; 8:45 am]
BILLING CODE 6560-50-P

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