Proposed Rule2025-11259
Air Plan Approval; Indiana; Regional Haze Plan for the Second Implementation Period
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
June 18, 2025
Issuing agencies
Environmental Protection Agency
Abstract
The Environmental Protection Agency (EPA) is proposing to approve the Indiana regional haze state implementation plan (SIP) revision submitted by the Indiana Department of Environmental Management (IDEM or Indiana) on December 29, 2021, as satisfying applicable requirements under the Clean Air Act (CAA) and EPA's Regional Haze Rule (RHR) for the program's second implementation period. EPA proposes to find that IDEM's SIP submission addresses the requirement that States must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas, and also addresses other applicable requirements for the second implementation period of the regional haze program. EPA is taking this action pursuant to sections 110 and 169A of the CAA.
Full Text
<html>
<head>
<title>Federal Register, Volume 90 Issue 116 (Wednesday, June 18, 2025)</title>
</head>
<body><pre>
[Federal Register Volume 90, Number 116 (Wednesday, June 18, 2025)]
[Proposed Rules]
[Pages 25944-25960]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2025-11259]
-----------------------------------------------------------------------
ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R05-OAR-2021-0963; FRL-12589-01-R5]
Air Plan Approval; Indiana; Regional Haze Plan for the Second
Implementation Period
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
-----------------------------------------------------------------------
SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve the Indiana regional haze state implementation plan (SIP)
revision submitted by the Indiana Department of Environmental
Management (IDEM or Indiana) on December 29, 2021, as satisfying
applicable requirements under the Clean Air Act (CAA) and EPA's
Regional Haze Rule (RHR) for the program's second implementation
period. EPA proposes to find that IDEM's SIP submission addresses the
requirement that States must periodically revise their long-term
strategies for making reasonable progress towards the national goal of
preventing any future, and remedying any existing, anthropogenic
impairment of visibility, including regional haze, in mandatory Class I
Federal areas, and also addresses other applicable requirements for the
second implementation period of the regional haze program. EPA is
taking this action pursuant to sections 110 and 169A of the CAA.
DATES: Written comments must be received on or before July 18, 2025.
ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R05-
OAR-2021-0963 at <a href="https://www.regulations.gov">https://www.regulations.gov</a> or via email to
<a href="/cdn-cgi/l/email-protection#b5d9d4dbd2d8d4db9bd8dcd6ddd4d0d9f5d0c5d49bd2dac3"><span class="__cf_email__" data-cfemail="3e525f5059535f501053575d565f5b527e5b4e5f10595148">[email protected]</span></a>. For comments submitted at <a href="http://Regulations.gov">Regulations.gov</a>,
follow the online instructions for submitting comments. Once submitted,
comments cannot be edited or removed from the docket. EPA may publish
any comment received to its public docket. Do not submit to EPA's
docket at <a href="https://www.regulations.gov">https://www.regulations.gov</a> any information you consider to
be confidential business information (CBI), Proprietary Business
Information (PBI), or other information whose disclosure is restricted
by statute. Multimedia submissions (audio, video, etc.) must be
accompanied by a written comment. The written comment is considered the
official comment and should include discussion of all points you wish
to make. EPA will generally not consider comments or comment contents
located outside of the primary submission (i.e., on the web, cloud, or
other file sharing system). For additional submission methods, please
contact the person identified in the FOR FURTHER INFORMATION CONTACT
section. For the full EPA public comment policy, information about CBI
or multimedia submissions, and general guidance on making effective
comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>.
FOR FURTHER INFORMATION CONTACT: Charles Hatten, Air and Radiation
Division (AR-18J), Environmental Protection Agency, Region 5, 77 West
Jackson Boulevard, Chicago, Illinois 60604, (312) 886-6031,
<a href="/cdn-cgi/l/email-protection#b4dcd5c0c0d1da9ad7dcd5c6d8d1c7f4d1c4d59ad3dbc2"><span class="__cf_email__" data-cfemail="a4ccc5d0d0c1ca8ac7ccc5d6c8c1d7e4c1d4c58ac3cbd2">[email protected]</span></a>. The EPA Region 5 office is open from 8:30 a.m.
to 4:30 p.m., Monday through Friday.
SUPPLEMENTARY INFORMATION: Throughout this document whenever ``we,''
``us,'' or ``our'' is used, we mean EPA.
[[Page 25945]]
Table of Contents
I. What Action is EPA Proposing?
II. Background and Requirements for Regional Haze Plans
A. Regional Haze Background
B. Roles of Agencies in Addressing Regional Haze
III. Requirements for Regional Haze Plans for the Second
Implementation Period
A. Reasonable Progress Goals (RPGs)
B. Monitoring Strategy and Other SIP Requirements
C. Requirements for Periodic Reports Describing Progress Towards
the RPGs
D. Requirements for State and Federal Land Manager Coordination
IV. EPA's Evaluation of Indiana's Regional Haze Submission for the
Second Implementation Period
A. Background on Indiana's First Implementation Period SIP
Submission
B. Indiana's Second Implementation Period SIP Submission and
EPA's Evaluation
C. Identification of Class I Areas
D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
E. Long-Term Strategy for Regional Haze
1. Selection of Sources for Analysis
2. Emission Measures Necessary to Make Reasonable Progress
3. Indiana's Long-Term Strategy
4. EPA's Evaluation of Indiana's Compliance with 40 CFR
51.308(f)(2)(i)
5. Consultation with States
6. Five Additional Factors
F. RPGs
G. Monitoring Strategy and Other Implementation Plan
Requirements
H. Requirements for Periodic Reports Describing Progress Towards
the RPGS
I. Requirements for State and Federal Land Manager Coordination
V. Proposed Action
VI. Statutory and Executive Order Reviews
I. What action is EPA proposing?
On December 29, 2021, IDEM submitted a SIP revision to address
regional haze requirements for the second implementation period. IDEM
submitted this SIP revision to satisfy the requirements pursuant to CAA
sections 169A and 169B and 40 CFR 51.308(f) related to the regional
haze program. EPA proposes to find that Indiana's regional haze SIP
submission for the second implementation period meets the applicable
statutory and regulatory requirements and thus proposes to approve
Indiana's submission into its SIP.
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 RHR as it applies to the current action.
---------------------------------------------------------------------------
\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>).
---------------------------------------------------------------------------
A. Regional Haze Background
In the 1977 CAA Amendments, Congress created a program for
protecting visibility in the nation's mandatory Class I Federal areas,
which include certain national parks and wilderness areas.\3\ CAA 169A.
The CAA establishes as a national goal the ``prevention of any future,
and the remedying of any existing, impairment of visibility in
mandatory class I Federal areas which impairment results from manmade
air pollution.'' CAA 169A(a)(1).
---------------------------------------------------------------------------
\3\ Areas statutorily designated as mandatory Class I Federal
areas consist of national parks exceeding 6,000 acres, wilderness
areas and national memorial parks exceeding 5,000 acres, and all
international parks that were in existence on August 7, 1977. CAA
162(a). There are 156 mandatory Class I areas. The list of areas to
which the requirements of the visibility protection program apply is
in 40 CFR part 81, subpart D.
---------------------------------------------------------------------------
Regional haze is visibility impairment that is produced by a
multitude of anthropogenic sources and activities which are located
across a broad geographic area and that emit pollutants that impair
visibility. Visibility impairing pollutants include fine and coarse
particulate matter (PM) (e.g., sulfates, nitrates, organic carbon,
elemental carbon, and soil dust) and their precursors (e.g., sulfur
dioxide (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\
---------------------------------------------------------------------------
\4\ There are several ways to measure the amount of visibility
impairment, i.e., haze. One such measurement is the deciview, which
is the principal metric used by the RHR. Under many circumstances, a
change in one deciview will be perceived by the human eye to be the
same on both clear and hazy days. The deciview is unitless. It is
proportional to the logarithm of the atmospheric extinction of
light, which is the perceived dimming of light due to its being
scattered and absorbed as it passes through the atmosphere.
Atmospheric light extinction (b\ext\) is a metric used to for
expressing visibility and is measured in inverse megameters (Mm-1).
The formula for the deciview is 10 ln (b\ext\)/10 Mm-1). 40 CFR
51.301.
---------------------------------------------------------------------------
To address regional haze visibility impairment, the 1999 RHR
established an iterative planning process that requires both States in
which Class I areas are located and States ``the emissions from which
may reasonably be anticipated to cause or contribute to any impairment
of visibility'' in a Class I area to periodically submit SIP revisions
to address such impairment. CAA 169A(b)(2); \5\ see also 40 CFR
51.308(b), (f) (establishing submission dates for iterative regional
haze SIP revisions); (64 FR 35714 at 35768, July 1, 1999).
On January 10, 2017 (82 FR 3078), EPA promulgated revisions to the
RHR, that apply for the second and subsequent implementation periods.
The reasonable progress requirements as revised in the 2017 rulemaking
(referred to here as the 2017 RHR Revisions) are codified at 40 CFR
51.308(f).
B. Roles of Agencies in Addressing Regional Haze
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, 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 lands 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.
---------------------------------------------------------------------------
\6\ RPOs are sometimes also referred to as ``multi-
jurisdictional organizations,'' or MJOs. For the purposes of this
notice, the terms RPO and MJO are synonymous.
---------------------------------------------------------------------------
The Lake Michigan Air Directors Consortium (LADCO) is an RPO that
includes the States of Illinois, Indiana, Michigan, Minnesota, Ohio,
and Wisconsin. LADCO's work is a collaborative effort of State
governments, Tribal governments, and various Federal agencies
established to
[[Page 25946]]
initiate and coordinate activities associated with the management of
regional haze, visibility, and other air quality issues in the Midwest.
Along with the six LADCO States, participants in LADCO's Regional Haze
Technical Workgroup include EPA, the U.S. National Park Service (NPS),
the U.S. Fish and Wildlife Service (FWS), and the U.S. Forest Service
(USFS).
III. Requirements for Regional Haze Plans for the Second Implementation
Period
Under the CAA and EPA's regulations, all 50 States, the District of
Columbia, and the U.S. Virgin Islands are required to submit regional
haze SIPs satisfying the applicable requirements for the second
implementation period of the regional haze program by July 31, 2021.
Each State's SIP must contain a long-term strategy for making
reasonable progress toward meeting the national goal of remedying any
existing and preventing any future anthropogenic visibility impairment
in Class I areas. CAA 169A(b)(2)(B). To this end, 40 CFR 51.308(f) lays
out the process by which States determine what constitutes their long-
term strategies, with the order of the requirements in 40 CFR
51.308(f)(1) through (3) generally mirroring the order of the steps in
the reasonable progress analysis \7\ and (f)(4) through (6) containing
additional, related requirements. Broadly speaking, a State first must
identify the Class I areas within the State and determine the Class I
areas outside the State in which visibility may be affected by
emissions from the State. These are the Class I areas that must be
addressed in the State's long-term strategy. See 40 CFR 51.308(f),
(f)(2). For each Class I area within its borders, a State must then
calculate the baseline (five-year average period of 2000-2004),
current, and natural visibility conditions (i.e., visibility conditions
without anthropogenic visibility impairment) for that area, as well as
the visibility improvement made to date and the ``uniform rate of
progress'' (URP). The 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 51.308(f)(2)(iv) separately provides five ``additional
factors'' \8\ that States must consider in developing their long-term
strategies. See 40 CFR 51.308(f)(2). A State evaluates potential
emission reduction measures for those selected sources and determines
which are necessary to make reasonable progress. Those measures are
then incorporated into the State's long-term strategy. After a State
has developed its long-term strategy, it then establishes RPGs for each
Class I area within its borders by modeling the visibility impacts of
all reasonable progress controls at the end of the second
implementation period, i.e., in 2028, as well as the impacts of other
requirements of the CAA. The RPGs include reasonable progress controls
not only for sources in the State in which the Class I area is located,
but also for sources in other States that contribute to visibility
impairment in that area. The RPGs are then compared to the baseline
visibility conditions and the URP to ensure that progress is being made
towards the statutory goal of preventing any future and remedying any
existing anthropogenic visibility impairment in Class I areas. 40 CFR
51.308(f)(2)-(3). There are additional requirements in the rule,
including FLM consultation, that apply to all visibility protection
SIPs and SIP revisions. See e.g., 40 CFR 51.308(i).
---------------------------------------------------------------------------
\7\ EPA explained in the 2017 RHR Revisions that we were
adopting new regulatory language in 40 CFR 51.308(f) that, unlike
the structure in 51.308(d), ``tracked the actual planning
sequence.'' (82 FR 3091, January 10, 2017).
\8\ The five ``additional factors'' forr consideration in
section 40 CFR 51.308(f)(2)(iv) are distinct from the four factors
listed in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that
states that must consider and apply to sources in determining
reasonable progress.
---------------------------------------------------------------------------
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.\9\ This is accomplished by considering the four factors--``the
costs of compliance, the time necessary for compliance, and the energy
and non-air quality environmental impacts of compliance, and the
remaining useful life of any existing source subject to such
requirements.'' CAA 169A(g)(1). EPA has explained that the four-factor
analysis is an assessment of potential emission reduction measures
(i.e., control options) for sources; ``use of the terms `compliance'
and `subject to such requirements' in section 169A(g)(1) strongly
indicates that Congress intended the relevant determination to be the
requirements with which sources would have to comply to satisfy the
CAA's reasonable progress mandate.'' 82 FR 3078 at 3091, January 10,
2017. Thus, for each source it has selected for four-factor
analysis,\10\ a State must consider a ``meaningful set'' of technically
feasible control options for reducing emissions of visibility impairing
pollutants. Id. at 3088.
---------------------------------------------------------------------------
\9\ The CAA provides that, ``[i]n determining reasonable
progress there shall be taken into consideration'' the four
statutory factors. CAA 169A(g)(1). However, in addition to four-
factor analyses for selected sources, groups of sources, or source
categories, a state may also consider additional emission reduction
measures for inclusion in its long-term strategy, e.g., from other
newly adopted, on-the-books, or on-the-way rules and measures for
sources not selected for four-factor analysis for the second
planning period.
\10\ ``Each source'' or ``particular source'' is used here as
shorthand. While a source-specific analysis is one way of applying
the four factors, neither the statute nor the RHR requires states to
evaluate individual sources. Rather, states have ``the flexibility
to conduct four-factor analyses for specific sources, groups of
sources or even entire source categories, depending on state policy
preferences and the specific circumstances of each state.'' 82 FR
3078 at 3088, January 10, 2017.
---------------------------------------------------------------------------
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.\11\ Ultimately, while States have discretion
[[Page 25947]]
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.''
---------------------------------------------------------------------------
\11\ See, e.g., Responses to Comments on Protection of
Visibility: Amendments to Requirements for State Plans; Proposed
Rule (81 FR 26942, May 4, 2016), Docket Number EPA-HQ-OAR-2015-0531,
U.S. Environmental Protection Agency at 186; 2019 Guidance at 36-37.
---------------------------------------------------------------------------
As explained above, 40 CFR 51.308(f)(2)(i) requires States to
determine the emission reduction measures for sources that are
necessary to make reasonable progress by considering the four factors.
Pursuant to 40 CFR 51.308(f)(2), measures that are necessary to make
reasonable progress towards the national visibility goal must be
included in a State's long-term strategy and in its SIP.\12\ 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.
---------------------------------------------------------------------------
\12\ States may choose to, but are not required to, include
measures in their long-term strategies beyond just the emission
reduction measures that are necessary for reasonable progress. For
example, states with smoke management programs may choose to submit
their smoke management plans to EPA for inclusion in their SIPs but
are not required to do so. See, e.g., 82 FR 3078 at 3108-09, January
10, 2017, (requirement to consider smoke management practices and
smoke management programs under 40 CFR 51.308(f)(2)(iv) does not
require states to adopt such practices or programs into their SIPs,
although they may elect to do so).
---------------------------------------------------------------------------
The characterization of information on each of the factors is also
subject to the documentation requirement in 40 CFR 51.308(f)(2)(iii).
The reasonable progress analysis is a technically complex exercise, and
also a flexible one that provides States with bounded discretion to
design and implement approaches appropriate to their circumstances.
Given this flexibility, 40 CFR 51.308(f)(2)(iii) plays an important
function in requiring a State to document the technical basis for its
decision making so that the public and EPA can comprehend and evaluate
the information and analysis the State relied upon to determine what
emission reduction measures must be in place to make reasonable
progress. The technical documentation must include the modeling,
monitoring, cost, engineering, and emissions information on which the
State relied to determine the measures necessary to make reasonable
progress.
Additionally, the RHR at 40 CFR 51.308(f)(2)(iv) separately
provides five ``additional factors'' \13\ 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.
---------------------------------------------------------------------------
\13\ The five ``additional factors'' for consideration in 40 CFR
51.308(f)(2)(iv) are distinct from the four factors listed in CAA
section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states must
consider and apply to sources in determining reasonable progress.
---------------------------------------------------------------------------
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 (RPGs)
RPGs ``measure the progress that is projected to be achieved by the
control measures States have determined are necessary to make
reasonable progress based on a four-factor analysis.'' 82 FR 3078 at
3091, January 10, 2017.
For the second implementation period, the RPGs are set for 2028.
RPGs are not enforceable targets, 40 CFR 51.308(f)(3)(iii). While
States are not legally obligated to achieve the visibility conditions
described in their RPGs, 40 CFR 51.308(f)(3)(i) requires that ``[t]he
long-term strategy and the RPGs must provide for an improvement in
visibility for the most impaired days since the baseline period and
ensure no degradation in visibility for the clearest days since the
baseline period.''
RPGs may also serve as a metric for assessing the amount of
progress a State is making towards the national visibility goal. To
support this approach, the RHR requires States with Class I areas to
compare the 2028 RPG for the most impaired days to the corresponding
point on the URP line (representing visibility conditions in 2028 if
visibility were to improve at a linear rate from conditions in the
baseline period of 2000-2004 to natural visibility conditions in 2064).
If the most impaired days RPG in 2028 is above the URP (i.e., if
visibility conditions are improving more slowly than the rate described
by the URP), each State that contributes to visibility impairment in
the Class I area must demonstrate, based on the four-factor analysis
required under 40 CFR 51.308(f)(2)(i), that no additional emission
reduction measures would be reasonable to include in its long-term
strategy. 40 CFR 51.308(f)(3)(ii). To this end, 40 CFR 51.308(f)(3)(ii)
requires that each State contributing to visibility impairment in a
Class I area that is projected to improve more slowly than the URP
provide ``a robust demonstration, including documenting the criteria
used to determine which sources or groups [of] sources were evaluated
and how the four factors required by paragraph (f)(2)(i) were taken
into consideration in selecting the measures for inclusion in its long-
term strategy.''
B. Monitoring Strategy and Other SIP Requirements
The provisions of 40 CFR 51.308(f)(6) require States to have
certain strategies and elements in place for assessing and reporting on
visibility. Individual requirements under this section apply either to
States with Class I areas within their borders, States with no Class I
areas but that are reasonably anticipated to cause or contribute to
visibility impairment in any Class I area, or both. Compliance with the
monitoring strategy requirement may be met through a State's
participation in the Interagency Monitoring of Protected Visual
Environments (IMPROVE) monitoring network, which is used to measure
visibility impairment caused by air pollution at the 156 Class I areas
covered by the visibility program. 40 CFR 51.308(f)(6), (f)(6)(i),
(f)(6)(iv).
All States' SIPs must provide for procedures by which monitoring
data and other information are used to determine the contribution of
emissions
[[Page 25948]]
from within the State to regional haze visibility impairment in
affected Class I areas, as well as a statewide inventory documenting
such emissions. 40 CFR 51.308(f)(6)(ii), (iii), (v). All States' SIPs
must also provide for any other elements, including reporting,
recordkeeping, and other measures, that are necessary for States to
assess and report on visibility. 40 CFR 51.308(f)(6)(vi).
C. Requirements for Periodic Reports Describing Progress Towards the
RPGs
The provisions of 40 CFR 51.308(f)(5) require a State's regional
haze SIP revision to address the requirements of paragraphs 40 CFR
51.308(g)(1) through (5) so that the plan revision due in 2021 will
serve also as a progress report addressing the period since submission
of the progress report for the first implementation period. The
regional haze progress report requirement is designed to inform the
public and EPA about a State's implementation of its existing long-term
strategy and whether such implementation is in fact resulting in the
expected visibility improvement. See 81 FR 26942, 26950, May 4, 2016,
(82 FR 3078 at 3119, January 10, 2017). To this end, every State's SIP
revision for the second implementation period is required to assess
changes in visibility conditions and describe the status of
implementation of all measures included in the State's long-term
strategy, including Best Available Retrofit Technology (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 EPA to evaluate whether FLM
consultation meeting the requirements of the RHR has occurred, the SIP
submission should include documentation of the timing and content of
such consultation. The SIP revision submitted to EPA must also describe
how the State addressed any comments provided by the FLMs. 40 CFR
51.308(i)(3). Finally, a SIP revision must provide procedures for
continuing consultation between the State and FLMs regarding the
State's visibility protection program, including development and review
of SIP revisions, five-year progress reports, and the implementation of
other programs having the potential to contribute to impairment of
visibility in Class I areas. 40 CFR 51.308(i)(4).
IV. EPA's Evaluation of Indiana's Regional Haze Submission for the
Second Implementation Period
A. Background on Indiana's First Implementation Period SIP Submission
Indiana submitted its regional haze SIP to EPA for the first
implementation period, 2007-2018, on January 14, 2011, and supplemented
it on March 10, 2011. The requirements for regional haze SIPs for the
first implementation period are contained in 40 CFR 51.308(d) and (e).
See 40 CFR 51.308(b).
On May 29, 2012, EPA finalized a limited approval of Indiana's 2011
SIP submission as satisfying the requirements for BART in 40 CFR
51.308(e) for non-electric generating units (EGUs) and for PM from
EGUs. EPA also approved the submission's BART limits for the Alcoa
Warrick facility, its identification of Class I areas that the State's
emissions affect, its demonstration that the State had consulted with
other States in establishing RPGs, and identification of emissions
reductions needed in Indiana to meet those goals. 77 FR 34218, June 11,
2012. On May 30, 2012, EPA issued a limited disapproval of Indiana's
2011 SIP submission because of deficiencies arising from the remand of
the Clean Air Interstate Rule (CAIR). In the same rulemaking, EPA
promulgated a Federal Implementation Plan (FIP) to replace Indiana's
reliance on CAIR with the Cross-State Air Pollution Rule (CSAPR). 77 FR
33642, June 7, 2012.
Pursuant to 40 CFR 51.308(g), Indiana was also responsible for
submitting a five-year progress report as a SIP revision for the first
implementation period, which it did on March 30, 2016. EPA approved
this five-year progress report as a revision to the Indiana SIP at 40
CFR 52.770(e) on January 23, 2018 (83 FR 4847, February 2, 2018).
On November 27, 2017, Indiana submitted a revision to its 2011
Regional Haze SIP submission to change reliance on CAIR to reliance on
CSAPR, which EPA approved on August 28, 2019, converting EPA's limited
approval/limited disapproval to a full approval and withdrawing the FIP
provisions that addressed the limited disapproval. 84 FR 46889,
September 6, 2019.
B. Indiana's Second Implementation Period SIP Submission and EPA's
Evaluation
In accordance with CAA sections 169A and the RHR at 40 CFR
51.308(f), Indiana submitted a SIP revision on December 29, 2021, to
address its regional haze obligations for the second implementation
period, which runs through 2028. Indiana provided a draft of its
regional haze SIP to the FLMs for consultation on May 18, 2021. Indiana
then provided a public comment period before submitting its SIP
revision to EPA.\14\
---------------------------------------------------------------------------
\14\ Indiana included the comments in appendices W, X, Ya, Yb,
and Z, and provided responses in appendices P, Q, R, S, T, U, and V
of its 2021 Regional Haze SIP submission.
---------------------------------------------------------------------------
The following sections describe Indiana's SIP submission, including
Indiana's assessment of progress made since the first implementation
period, in reducing emissions of visibility impairing pollutants, and
the visibility improvement progress at nearby Class I areas. These
sections also contain EPA's evaluation of Indiana's submission against
the requirements of the CAA and the RHR for the second implementation
period of the regional haze program.
C. Identification of Class I Areas
The provisions of section 169A(b)(2) of the CAA require each State
in which any Class I area is located or ``the emissions from which may
reasonably be anticipated to cause or contribute to any impairment of
visibility'' in a Class I area to have a plan for making reasonable
progress toward the national visibility goal. The RHR implements this
statutory requirement at 40 CFR 51.308(f), which provides that each
State's plan ``must address regional haze in each mandatory Class I
Federal area located within the State and in each mandatory Class I
Federal area located outside the State that may be affected by
emissions from within the State,'' and (f)(2), which requires each
State's plan to include a long-term strategy that addresses regional
haze in such Class I areas.
Indiana has no Class I areas within its borders that are among the
156 mandatory Class I Federal areas where EPA deemed visibility to be
an important value. See 40 CFR part 81, subpart D. Thus, IDEM only
considered
[[Page 25949]]
out-of-state mandatory Class I Federal areas.
Indiana is a member of LADCO and participated in its regional
approach for developing a strategy for making reasonable progress
towards the national visibility goal in the northern Midwest Class I
areas. IDEM reviewed technical analyses conducted by LADCO to determine
which Class I areas outside the State are affected by Indiana emission
sources. For the second regional haze implementation period, to
determine LADCO member State contributions to impaired visibility in
all Class I areas, LADCO used the Comprehensive Air Quality Model with
extensions applying Particulate Matter Source Apportionment Tool. LADCO
tagged emissions from individual States and several multi-state regions
as well as individual point sources and inventory source groups to
apportion emissions to States and regions. This included 27 tagged
source categories, nine of which were source categories or individual
sources in Indiana: (1) Indiana non-point sources, (2) Rockport EGUs,
(3) Gibson EGUs, (4) all other Indiana EGUs, (5) Indiana cement
manufacturing facilities, (6) Indiana iron and steel facilities, (7)
Indiana plastics and resin manufacturing facilities, (8) Indiana
aluminum production facilities, and (9) all other Indiana point
sources. LADCO assessed relative visibility impacts in 2028 by
projecting representative emissions inventories and known emission
controls from 2016.\15\ A group of RPOs, States, and EPA established
2016 as the base year for a national air quality modeling platform for
future ozone, PM<INF>2.5</INF>, and regional haze SIP development
because of fairly typical ozone conditions and wildfire conditions.\16\
LADCO relied upon EPA's inventory estimates for 2016 and 2028 for most
emission sectors as described in EPA's September 19, 2019,
``Availability of Modeling Data and Associated Technical Support
Document for the EPA's Updated 2028 Visibility Air Quality Modeling,''
(EPA's Updated 2028 Visibility Air Quality Modeling).\17\ For EGUs,
LADCO used forecasts from the Eastern Regional Technical Advisory
Committee (ERTAC) based on continuous emissions monitoring data from
2016 instead of the Integrated Planning Model used in EPA's 2016
modeling platform. LADCO also incorporated state-reported changes to
EGUs received through September 2020 to estimate 2028 EGU emissions,
which was considered by LADCO to be the best available information on
EGU forecasts for the Midwest and Eastern U.S. available at the time.
---------------------------------------------------------------------------
\15\ See section 24 and appendix L of Indiana's 2021 SIP
submittal for details of the analysis and source-apportioned
visibility contributions at Class I areas within the LADCO region
for regional haze second planning period that are documented in
LADCO's ``Modeling and Analysis for Demonstrating Reasonable
Progress for the Regional Haze Rule 2018-2028 Planning Period:
Technical Support Document,'' June 17, 2021.
\16\ See ``Base Year Selection Workgroup Final Report,''
produced by the Inventory Collaborative Base Year Selection
Workgroup, April 5, 2017. <a href="https://www.wrapair2.org/pdf/2017-12-12_Base_Year_Selection_Report_V1.1.pdf">https://www.wrapair2.org/pdf/2017-12-12_Base_Year_Selection_Report_V1.1.pdf</a>.
\17\ EPA, Office of Air Quality Planning and Standards,
``Availability of Modeling Data and Associate Technical Support
Document for EPA's Updated 2028 Visibility Air Quality Modeling,''
September 19, 2019. <a href="https://www.epa.gov/sites/default/files/2019-10/documents/updated_2028_regional_haze_modeling-tsd-2019_0.pdf">https://www.epa.gov/sites/default/files/2019-10/documents/updated_2028_regional_haze_modeling-tsd-2019_0.pdf</a>.
---------------------------------------------------------------------------
Based on LADCO's source apportionment modeling results for 2028,
IDEM identified 17 out-of-state Class I areas where Indiana's
contribution to the total light extinction was 1.5 percent or greater.
IDEM also included three additional Class I areas below the 1.5 percent
threshold: Boundary Waters Canoe Area Wilderness (Minnesota) and
Voyageurs National Park (Minnesota) since they are part of the LADCO
region, as well as Caney Creek (Arkansas) based on a request for inter-
state consultation from Arkansas. IDEM found that the 1.5 percent
threshold provided adequate geographic coverage of potential visibility
impacts from Indiana on surrounding Class I areas and that the modeling
of those areas would be representative of Class I areas further from
the State. These Class I areas, along with Indiana's 2028 projected
contributions to the total light extinction, are: Mammoth Cave National
Park in Kentucky (11.2 percent); Sipsey Wilderness Area in Alabama
(5.90 percent); Dolly Sods and Otter Creek Wilderness Areas in West
Virginia (5.56 percent); Great Smoky Mountains National Park and Joyce-
Kilmer-Slickrock Wilderness Area in Tennessee (5.29 percent);
Shenandoah National Park in Virginia (5.14 percent); Cohutta Wilderness
Area in Georgia (4.83 percent); Mingo Wilderness Area in Missouri (4.16
percent); Seney Wilderness Area in Michigan (4.01 percent); James River
Face Wilderness Area in Virginia (3.75 percent); Linville Gorge
Wilderness Area in North Carolina (2.84 percent); Lye Brook Wilderness
Area in Vermont (2.33 percent); Brigantine Wilderness Area in New
Jersey (2.30 percent); Shining Rock Wilderness Area in North Carolina
(2.17 percent); Upper Buffalo Wilderness Area in Arkansas (2.02
percent); Hercules-Glades Wilderness Area in Missouri (2.01 percent);
Swanquarter National Wildlife Refuge in North Carolina (1.85 percent);
Isle Royale National Park in Michigan (1.85 percent); Caney Creek
Wilderness Area in Arkansas (1.10 percent); Boundary Waters Canoe Area
Wilderness in Minnesota (0.74 percent); and Voyageurs National Park in
Minnesota (0.49 percent).\18\ At each of these Class I areas, EPA notes
that the visibility conditions in LADCO's modeling as well as EPA's
Updated 2028 Visibility Air Quality Modeling are projected to be below
their respective glidepaths in 2028 as depicted in Section 23 of
Indiana's 2021 Regional Haze SIP submission. Visibility conditions at
the Class I areas most impacted by Indiana are projected to be below
their respective glidepaths in 2028 at Mammoth Cave National Park by
2.16 deciviews (dv), Sipsey Wilderness Area by 2.44 dv, Dolly Sods and
Otter Creek Wilderness Areas by 4.33 dv, Great Smoky Mountains National
Park and Joyce-Kilmer-Slickrock Wilderness Area by 5.43 dv, and
Shenandoah National Park by 4.98 dv. IDEM addressed each of these Class
I areas as well as requests from their host RPOs and States in
Indiana's 2021 Regional Haze SIP Sections 22-25 and appendix AA.
---------------------------------------------------------------------------
\18\ The list of Class I areas impacted by Indiana, including
the 2028 projections for total light extinction and Indiana's
contribution, is found in Table 23-1 of Indiana's 2021 Regional Haze
SIP submittal.
---------------------------------------------------------------------------
D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
The provisions of 40 CFR 51.308(f)(1) require States to determine
the following for ``each mandatory Class I Federal area located within
the State'': baseline visibility conditions for the most impaired and
clearest days, natural visibility conditions for the most impaired and
clearest days, progress to date for the most impaired and clearest
days, the differences between current visibility conditions and natural
visibility conditions, and the URP. This section also provides the
option for States to propose adjustments to the URP line for a Class I
area to account for visibility impacts from anthropogenic sources
outside the United States and/or the impacts from wildland prescribed
fires that were conducted for certain, specified objectives. 40 CFR
51.308(f)(1)(vi)(B).
Indiana has no mandatory Class I areas within its borders to which
the requirements of the visibility protection program apply in 40 CFR
part 81,
[[Page 25950]]
subpart D, and therefore, 40 CFR 51.308(f)(1) and its requirements do
not apply.
E. Long-Term Strategy for Regional Haze
Each State having a Class I area within its borders or emissions
that may affect visibility in a Class I area must develop a long-term
strategy for making reasonable progress towards the national visibility
goal. CAA 169A(b)(2)(B). 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
strategies, a State must also consider the five additional factors in
40 CFR 51.308(f)(2)(iv). As part of its reasonable progress
determinations, the State must describe the criteria used to determine
which sources or group of sources were evaluated (i.e., subjected to
four-factor analysis) for the second implementation period and how the
four factors were taken into consideration in selecting the emission
reduction measures for inclusion in the long-term strategy. 40 CFR
51.308(f)(2)(iii).
1. Selection of Sources for Analysis
States may rely on technical information developed by the RPOs of
which they are members to select sources for four-factor analysis and
to conduct that analysis, as well as to satisfy the documentation
requirements under 40 CFR 51.308(f). States may also satisfy the
requirement of 40 CFR 51.308(f)(2)(ii) to engage in interstate
consultation with other States that have emissions that are reasonably
anticipated to contribute to visibility impairment in a given Class I
area under the auspices of intra- and inter-RPO engagement.
In developing a process for selecting sources for possible
additional control measures during the second planning period, IDEM
considered NO<INF>X</INF>, SO<INF>2</INF>, and NH<INF>3</INF> emissions
as precursors to the formation of ammonium sulfate, ammonium nitrate,
and organic carbon that can impair visibility. Of these precursors,
LADCO's June 17, 2021, Technical Support Document ``Modeling and
Analysis for Demonstrating Reasonable Progress for the Regional Haze
Rule 2018-2028 Planning Period,'' (LADCO's 2021 TSD) \19\ provided an
analysis of the IMPROVE monitoring data. The analysis demonstrated that
NO<INF>X</INF> and SO<INF>2</INF> emissions lead to the formation of
the particulate species of nitrate and sulfate that currently
contribute more to visibility impairment in the LADCO Class I Areas
than PM<INF>2.5</INF>, NH<INF>3</INF>, and VOC. The LADCO Class I Areas
consist of Boundary Waters Canoe Area Wilderness and Voyageurs National
Park in Minnesota, as well as Isle Royale National Park and Seney
Wilderness Area in Michigan. For this reason, Indiana chose to focus on
potential reductions in emissions of NO<INF>X</INF> and SO<INF>2,</INF>
which Indiana found would be a reasonable approach for the second
implementation period as noted in the ``Guidance on Regional Haze State
Implementation Plans for the Second Implementation Period,'' EPA Office
of Air Quality Planning and Standards, Research Triangle Park, August
20, 2019 (``2019 Guidance'') at page 12.\20\
---------------------------------------------------------------------------
\19\ LADCO's 2021 TSD is contained in appendix L of Indiana's
2021 Regional Haze SIP submittal.
\20\ <a href="https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period">https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period</a>.
---------------------------------------------------------------------------
In selecting sources for a potential four-factor analysis, IDEM
followed the methodology in LADCO's October 14, 2020, technical
memorandum ``Description of the Sources and Methods Used to Support Q/d
Analysis for the 2nd Regional Haze Planning Period'' \21\ and section 5
of the LADCO's 2021 TSD. IDEM generated a list of sources based on
total process-level emissions (Q) divided by distance (d) to the
nearest Class I area, where Q/d was used as a surrogate quantitative
metric of visibility impact in lieu of air quality modeling results.
For Q, total emissions refer to the sum of NO<INF>X</INF> and
SO<INF>2</INF>, and IDEM chose to use data from the National Emissions
Inventory, EPA's Emissions Inventory System \22\ for 2016-2018, and
Clean Air Markets Program Data (CAMPD) \23\ for 2018 to represent the
most current operations at the time as a reflection of decreasing
emissions overall. For Q/d, the distance to the closest Class I area
for all selected sources was Mammoth Cave. IDEM chose a Q/d threshold
of five to capture a variety of higher emitting sources that were
representative of 85 percent of SO<INF>2</INF> and 77 percent of
NO<INF>X</INF> emissions from Indiana sources and to screen out sources
with either lower emissions or located at farther distances from the
Class I areas with lower visibility impacts.\24\ This process
identified 20 sources for a possible four-factor analysis: 11 power
generating stations and nine non-EGUs (such as steel mills, cement
kilns, a plastics manufacturer, an aluminum smelter, and electric
services operations).
---------------------------------------------------------------------------
\21\ LADCO's October 14, 2020, technical memorandum
``Description of the Sources and Methods Used to Support Q/d
Analysis for the 2nd Regional Haze Planning Period'' is included in
appendix M of Indiana's 2021 Regional Haze SIP submittal.
\22\ EPA's 2016-2018 Emissions Inventory System data is included
in appendix O of Indiana's 2021 Regional Haze SIP submittal. EPA's
Emissions Inventory System data is publicly available at <a href="https://www.epa.gov/air-emissions-inventories/emissions-inventory-system-eis-gateway">https://www.epa.gov/air-emissions-inventories/emissions-inventory-system-eis-gateway</a>.
\23\ The 2018 CAMPD information is included in appendix E of
Indiana's 2021 Regional Haze SIP submittal. CAMPD information is
publicly available at <a href="https://campd.epa.gov/">https://campd.epa.gov/</a>.
\24\ Based on 2018 emissions. See Indiana's 2021 Regional Haze
SIP submission, Table 7-1 and appendix N. The 2018 Indiana Emissions
Summary Data from sources reporting under Indiana Administrative
Code Title 326, Article 2, Rule 6 is included in the docket and is
publicly available at <a href="https://www.in.gov/idem/airquality/reporting/emissions-summary-data/">https://www.in.gov/idem/airquality/reporting/emissions-summary-data/</a>.
---------------------------------------------------------------------------
IDEM's source selection approach identified the following 36 EGUs
units at the 11 power generating stations: Indiana Michigan Power
Company, dba American Electric Power--Rockport Plant (AEP--Rockport),
Boilers MB1 and MB2; Duke Energy, Inc.--Gibson Generating Station
(Duke--Gibson), Units 1, 2, 3, 4, and 5; AES Indiana--Petersburg
Generating Station (AES--Petersburg), Units 1, 2, 3, and 4; Indiana-
Kentucky Electric Corporation (IKEC) and Ohio Valley Electric
Corporation--Clifty Creek Station (IKEC--Clifty Creek), Units 1, 2, 3,
4, 5, and 6; Duke Energy Indiana, LLC--Cayuga Generating Station
(Duke--Cayuga), Units 1 and 2; Southern Indiana Gas and Electric
Company (SIGECO)--A.B. Brown Generating Station (SIGECO--A.B. Brown),
Units 1 and 2; Alcoa Power Generating, Inc.--Warrick Power Plant
(Alcoa--Warrick Power Plant), Unit 4; SIGECO--F.B. Culley Generating
Station (SIGECO--F.B. Culley), Units 2 and 3; Hoosier Energy REC,
Inc.--Merom Generating Station (Hoosier Energy--Merom), Units 1SG1,
2SG1; Northern Indiana Public Service Company, LLC (NIPSCO)--R.M.
Schahfer Generating Station (NIPSCO--R.M. Schahfer), Units 14, 15, 16A,
16B, 17, and 18; and Duke Energy Indiana, LLC--R. Gallagher Generating
Station (Duke--Gallagher), Units 2 and 4.
The nine non-EGU facilities are: Warrick Newco LLC (Alcoa--Warrick
Operations); Cleveland-Cliffs Steel, LLC--Burns Harbor, LLC (Burns
Harbor); Lehigh Cement Company, LLC--Mitchell Plant, Lawrence County
(Lehigh Cement--Mitchell Plant); Cokenergy LLC; Cleveland-Cliffs Steel,
LLC--Indiana Harbor East (Indiana Harbor East); Lone Star Industries,
Inc. dba Buzzi Unicem USA--Greencastle Plant (Lone Star Industries--
Greencastle); United States Steel Corporation--Gary Works (U.S. Steel--
Gary Works); Cleveland-Cliffs Steel, LLC--Indiana Harbor West (Indiana
[[Page 25951]]
Harbor West); and SABIC Innovative Plastics--Mt. Vernon LLC.\25\
---------------------------------------------------------------------------
\25\ Since the time that IDEM evaluated these sources, some
facilities have changed names. ArcelorMittal USA LLC--Indiana Harbor
East is now Cleveland-Cliffs Steel, LLC--Indiana Harbor East.
ArcelorMittal USA LLC--Indiana Harbor West is now Cleveland-Cliffs
Steel, LLC--Indiana Harbor West. Arcelor Mittal--Burns Harbor, LLC
is now Cleveland-Cliffs Steel, LLC--Burns Harbor. Alcoa Warrick
Operations LLC is now Warrick Newco LLC. Lehigh Cement Company LLC--
Mitchell Plant is now Heidelberg Materials US Cement LLC--Mitchell
Plant.
---------------------------------------------------------------------------
During the FLM consultation process, NPS and USFS provided IDEM
with their lists of sources for potential four-factor analyses based on
Q/d; however, none of the additional sources identified by NPS or USFS
met IDEM's threshold of Q/d greater than five.\26\ NPS later agreed
that the units IDEM identified represented a reasonable group of
sources for potential four-factor analyses. The FLM consultation on
source selection is further discussed in Section 2.2 of EPA's April 22,
2025 Technical Support Document (TSD) for this proposed rulemaking,
which is included in the docket.
---------------------------------------------------------------------------
\26\ The lists of sources suggested for a four-factor analysis
by NPS and USFS appear in appendix N of Indiana's 2021 Regional Haze
SIP submittal. Comments from NPS are provided in appendix W of
Indiana's 2021 Regional Haze SIP submission.
---------------------------------------------------------------------------
IDEM further refined the list of selected sources by considering
whether units would continue to operate or whether they had existing
effective controls such that a full four-factor analysis would likely
result in a conclusion that no further controls are necessary. Applying
these criteria, IDEM determined a full four-factor analysis was not
necessary for the 36 EGUs identified. IDEM selected the remaining nine
non-EGU facilities for a four-factor analysis as described below. Of
the emission units that met Indiana's Q/d source selection criteria,
eight EGUs and one non-EGU facility are no longer operating: Duke--
Gallagher Units 2 and 4 ; NIPSCO--R.M. Schahfer Units 14 and 15 ; AES--
Petersburg Unit 1 (2021) and Unit 2 ; SIGECO--A.B. Brown Units 1 and 2,
and Lehigh Cement--Mitchell Kilns 1, 2, and 3.
For the units that are no longer operating, permitting changes,\27\
Unit Exemption forms,\28\ and verification from the regional
transmission organization \29\ are included in the docket.\30\ Any
major stationary source upon restart is subject to permitting as a new
source and must comply with requirements pertaining to Federal New
Source Review and Prevention of Significant Deterioration requirements
as well as Indiana Administrative Code (IAC), Title 326, Article 2.\31\
---------------------------------------------------------------------------
\27\ The following permits are available in the docket and on
IDEM's website: Duke--Gallagher Units 2 and 4, title V permit 043-
44081-00004, <a href="https://permits.air.idem.in.gov/44081f.pdf">https://permits.air.idem.in.gov/44081f.pdf</a>; NIPSCO--
R.M. Schahfer Units 14 and 15, title V permit 073-45762-00008,
<a href="https://permits.air.idem.in.gov/45762f.pdf">https://permits.air.idem.in.gov/45762f.pdf</a>; AES--Petersburg Unit 1,
title V permit 125-44230-00002, <a href="https://permits.air.idem.in.gov/44230f.pdf">https://permits.air.idem.in.gov/44230f.pdf</a> and Unit 2 title V permit 125-46357-00002, <a href="https://permits.air.idem.in.gov/46357f.pdf">https://permits.air.idem.in.gov/46357f.pdf</a>; SIGECO--A.B. Brown Units 1 and
2, title V permit 129-47510-00010, <a href="https://permits.air.idem.in.gov/47510f.pdf">https://permits.air.idem.in.gov/47510f.pdf</a>; and Lehigh Cement--Mitchell, Kilns 1, 2, and 3, title V
permit 093-47798-00002, <a href="https://permits.air.idem.in.gov/47798f.pdf">https://permits.air.idem.in.gov/47798f.pdf</a>.
\28\ The EGUs no longer operating have been certified by the
source owner or operator under the provisions for Unit Exemptions in
the Acid Rain Program and/or CSAPR NO<INF>X</INF> and SO<INF>2</INF>
Trading Programs.. See 40 CFR 72.8, 40 CFR 97.405, 40 CFR 97.505, 40
CFR 97.605, CFR 97.705, 40 CFR 97.805. Copies of Unit Exemption
forms for each of these units are included in the docket.
\29\ The list of generators from the Midwest Independent System
Operator (MISO) regional transmission organization is available in
the docket.
\30\ Publicly available information that EPA considered in
addition to the information provided in Indiana's 2021 Regional Haze
SIP submission and referenced by citations in the notice of proposed
rulemaking is included in the docket, designated by files names
preceded by ``Indiana.''
\31\ Indiana Administrative Code is publicly available at
<a href="https://iar.iga.in.gov/code/2026/326">https://iar.iga.in.gov/code/2026/326</a>.
---------------------------------------------------------------------------
For the remaining EGUs continuing to operate, IDEM examined the
facilities for existing effective controls in determining that a full
four-factor analysis would likely result in the conclusion that no
further controls are necessary for reasonable progress in the second
implementation period as described in Section 2 of EPA's April 22,
2025, TSD.
Citing to the flexibility allowed under the RHR, Indiana plans to
reexamine the EGUs in the third planning period because the State has
found that the landscape for the EGU sector has changed dramatically
since the last planning period and is continuing to change in the
second implementation period. In addition, IDEM states, ``fuel costs
have upended the order in which resources are dispatched by [MISO] to
meet the region's power generation needs and maintain adequate power
grid management in the future. Coal fired units that were previously
dispatched first are now dispatched last. This change in economic
driven dispatching is expected to result in less reliance on the
remaining coal fired EGUs and accelerated retirement. As such, Indiana
believes that conducting four-factor analyses for EGUs during the next
planning period would result in a better use of resources because much
of what the State would require based on four-factor analyses conducted
for the EGUs would become moot as the EGU sector remains in flux as
sources continue to shutdown units, convert to natural gas, and rely
more on renewable energy.'' See responses 2 and 3, appendix V of
Indiana's 2021 Regional Haze SIP submission.
EPA has provided clarification regarding when it is appropriate to
forgo a four-factor analysis for sources with existing effective
control measures. As explained in the 2019 Guidance, Section 3(f), ``A
source may already have effective controls in place as a result of a
previous regional haze SIP or to meet another CAA requirement.''
Section 3(f) goes on to provide ``examples, which are intended to
illustrate (in a non-exhaustive fashion) scenarios in which EPA
believes it may be reasonable for a State not to select a particular
source for further analysis.''
As discussed below, IDEM provided information to demonstrate that
the EGUs have existing effective control measures as described in the
examples in the 2019 Regional Haze Guidance, Section 3(f).\32\ In
addition to IDEM's analysis of emissions from 2007 to 2019, EPA also
considered limits contained in existing permits \33\ and 2018 to 2023
CAMPD information showing that each unit has consistently implemented
their existing measures and have achieved, using those measures, a
reasonably consistent emission rate. With emission limits in the title
V permits, provisions in Federal consent decrees, historical data
showing relatively consistent or declining NO<INF>X</INF> and
SO<INF>2</INF> annual emissions and emission rates, as well as 2028
projections, the overall emissions are not expected to increase in the
future. As such, IDEM determined that the existing control measures are
not necessary to prevent future emission increases and thus not
necessary to make reasonable progress in the second implementation
period and that pursuing additional emission reductions through the
addition of new emission control equipment or emissions limitations is
not reasonable as a cost-effective method. Section 2.4 of EPA's April
22, 2025, TSD provides a detailed summary of IDEM's assessment of the
EGUs continuing to operate.
---------------------------------------------------------------------------
\32\ See also Table 8.3 and appendix F of Indiana's 2021
Regional Haze SIP submission.
\33\ IDEM's Air Quality Permits are publicly available at
<a href="https://www.in.gov/ai/appfiles/idem-caats/">https://www.in.gov/ai/appfiles/idem-caats/</a>.
---------------------------------------------------------------------------
After addressing the EGUs as described above and in EPA's April 22,
2025 TSD, Indiana provided site-specific four-factor analyses for the
remaining nine non-EGU facilities identified by IDEM's Q/d source
selection threshold: Alcoa--Warrick Operations; Burns Harbor; Lehigh
Cement--Mitchell; Cokenergy LLC;
[[Page 25952]]
Indiana Harbor East; Lone Star Industries--Greencastle; U.S. Steel--
Gary Works; Indiana Harbor West; and SABIC Innovative Plastics--Mt.
Vernon LLC. The background and four-factor analysis for each of the
nine units is described below.
2. Emission Measures Necessary To Make Reasonable Progress
The provisions of 40 CFR 51.308(f)(2)(i) require States to evaluate
and determine the emission reduction measures that are necessary to
make reasonable progress by applying the four statutory factors to
sources in a control analysis. The emission reduction measures that are
necessary to make reasonable progress must be included in the long-term
strategy. 40 CFR 51.308(f)(2).
IDEM's evaluation of each of the nine non-EGU facilities identified
through its Q/d source selection process is described in Section 2.5
and 3 of EPA's April 22, 2025 TSD. Each of the four-factor analyses
provided for these facilities considered all four statutory factors and
appropriately followed the methods in the EPA Air Pollution Control
Cost Manual.\34\
---------------------------------------------------------------------------
\34\ See the EPA's Air Pollution Control Cost Manual available
at <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>.
---------------------------------------------------------------------------
In addition to the four-factor analyses and evaluations provided by
IDEM, EPA also considered limits contained in existing permits and
information from Indiana's Emissions Summary Data \35\ showing that
each unit has consistently implemented their existing measures and have
achieved, using those measures, reasonably consistent emission rates.
With limits in the title V permits, provisions in Federal consent
decrees, historical data showing relatively consistent or declining
NO<INF>X</INF> and SO<INF>2</INF> annual emissions, and emission rates
as well as 2028 projections of overall emissions not expected to
increase in the future, IDEM determined that the existing emission
control measures for each of the non-EGUs are not necessary to prevent
future emission increase in the second implementation period and thus
not necessary for reasonable progress. As such, IDEM determined that
additional control measures are not necessary to make reasonable
progress in the second implementation period and that pursuing
additional emission reductions through the addition of new emission
control equipment or emissions limitations is not cost effective.
---------------------------------------------------------------------------
\35\ Indiana's Emissions Summary Data for 2008--2022 is
available in the docket and at <a href="https://www.in.gov/idem/airquality/reporting/emissions-summary-data/">https://www.in.gov/idem/airquality/reporting/emissions-summary-data/</a>.
---------------------------------------------------------------------------
3. Indiana's Long-Term Strategy
Each State's long-term strategy must include the enforceable
emission limitations, compliance schedules, and other measures that are
necessary to make reasonable progress. 40 CFR 51.308(f)(2). After
considering information regarding existing effective controls, analyses
under the four statutory factors in 40 CFR 51.308(f)(2)(i), and the
five additional factors in 40 CFR 51.308(f)(2)(iv) in addition to other
requirements in 40 CFR 51.308(f)(2)(ii) described below, Indiana
developed the State's long-term strategy for the second implementation
planning period. The measures below represent reductions beyond those
planned in the first implementation planning period, as well as
emission reductions due to ongoing air pollution control programs,
including those that were factored into LADCO's 2028 modeling. The
following measures are already permanent and federally enforceable.
On-the-books controls in the second implementation period include:
<bullet> Tier 2 Motor Vehicle Emissions and Gasoline Standards Rule
(40 CFR 80, 85, and 86)
<bullet> Tier 3 Motor Vehicle Emission and Fuel Standards (40 CFR
79, 80, 85, 86, 600, 1036, 1037, 1039, 1042, 1048, 1054, 1065, 1066)
<bullet> Tier 4 Non-road Engines and Diesel Fuel Rule (40 CFR 9,
69, 80 86, 89, 94, 1039, 1048, 1051, 1065, 1068)
<bullet> Heavy-Duty Diesel Engine and Highway Diesel Fuel Rule (40
CFR 69, 80, 86)
<bullet> Data Requirements Rule for the 2010 SO<INF>2</INF> NAAQS
(40 CFR 51, Subpart BB)
<bullet> Mercury and Air Toxics Standards (MATS) (40 CFR 63,
subpart UUUUU)
<bullet> Boiler Maximum Achievable Control Technology (MACT) (40
CFR 63, Subpart DDDDD
On-the-way controls that reflect additional emission reductions
expected by 2028 include:
<bullet> Revised CSAPR Update (40 CFR 97, subpart GGGGG)
4. EPA's Evaluation of Indiana's Compliance With 40 CFR 51.308(f)(2)(i)
EPA proposes to find that Indiana has satisfied the requirements of
40 CFR 51.308(f)(2)(i) related to evaluating sources and determining
the emission reduction measures that are necessary to make reasonable
progress by considering the four statutory factors. Indiana's selection
of sources and evaluation of control measures was reasonable and
consistent with the requirements of 40 CFR 51.308(f)(2)(i). Considering
the four statutory factors, the projected 2028 visibility conditions
for Class I areas influenced by emissions from Indiana sources all
being below the URP in 2028, the historical emissions data, the
emissions reductions, and the current control technologies, EPA also
finds Indiana reasonably concluded that no additional measures are
necessary to make reasonable progress in the second planning period. As
detailed further below, EPA proposes to approve Indiana's long-term
strategy under 40 CFR 51.308(f)(2).
In line with recent proposals from EPA,\36\ it is the Agency's
policy that, where visibility conditions for a Class I area impacted by
a State are below the URP and the State has considered the four
statutory factors, the State will have presumptively demonstrated
reasonable progress for the second planning period for that area. In
developing the regulations required by CAA section 169A(b), 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).\37\
---------------------------------------------------------------------------
\36\ 90 FR 16478; 16483-16484, April 18, 2025.
\37\ 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 at 3091-3092.
---------------------------------------------------------------------------
EPA's new policy is that so long as the Class I areas impacted by a
State are below the URP in 2028 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 Indiana's SIP and as
further detailed in the paragraphs that follow, EPA agrees with
Indiana's determination that, for the second planning period, no
additional measures are necessary to achieve reasonable
[[Page 25953]]
progress towards natural visibility at Class I areas impacted by
emissions from Indiana sources.
The SIP submittal included evaluations for 20 emissions sources,
including consideration of the four statutory factors for nine non-EGU
facilities and consideration of existing measures at a further 11 power
generating stations. Based on these evaluations and analyses, the State
determined that no additional measures were necessary for reasonable
progress. In reaching this determination, Indiana also considered the
emissions reductions and visibility improvements that have already
occurred in the second planning period in nearby Class I areas.
For Indiana's source selection methodology, IDEM targeted the
sources with the highest potential to impair visibility at mandatory
Class I areas. IDEM included a thorough description of its source
selection methodology. Starting with LADCO's Q/d methodology and
focusing on SO<INF>2</INF> and NO<INF>X</INF> as the predominant
species contributing to visibility impairment in the LADCO Class I
areas, IDEM queried data for all sources reporting to the National
Emissions Inventory, EPA's Emissions Inventory System for 2016--2018,
and CAMPD \38\ for 2018 to represent the most current operations at the
time. IDEM appropriately chose a Q/d threshold of 5 to capture a
variety of higher emitting sources and to screen out sources with
either lower emissions or located at farther distances from the Class I
areas. As noted in section IV.E.1, above, this process identified 20
sources for a possible four-factor analysis. Overall, the sources
selected by IDEM for potential four-factor analysis accounted for 81
percent of the total emissions for SO<INF>2</INF> and NO<INF>X</INF>
for all sources reporting under Indiana's Emission Reporting Rule at
Title 326, Article 2, Rule 6 of the Indiana Administrative Code (326
IAC 2-6) in 2018, including 85 percent of SO<INF>2</INF> and 77 percent
of NO<INF>X</INF>.
---------------------------------------------------------------------------
\38\ The 2018 CAMPD information that IDEM relied upon is
included in appendix E of Indiana's 2021 Regional Haze SIP
submittal.
---------------------------------------------------------------------------
In determining which facilities to evaluate through a four-factor
analysis, IDEM refined the list of sources selected using its Q/d
threshold by providing adequate justification for no further analysis
where sources had existing effective controls. For EGUs that are now no
longer operating, IDEM provided information on emissions from 2009 to
2019 and results of source apportionment modeling to demonstrate
statewide emission reductions and projections for SO<INF>2</INF> and
NO<INF>X</INF>. Compared to the 2018 inventories used in IDEM's source
selection process,\39\ the emissions reductions from the sources no
longer operating represent decreases of SO<INF>2</INF> by over 7,000
tons per year (tpy) and NO<INF>X</INF> by over 9,000 tpy from all the
sources IDEM selected with Q/d greater than five. These include: Duke--
Gallagher Units 2 and 4 (1,149 ton SO<INF>2</INF> and 535 tons
NO<INF>X</INF>); NIPSCO--R.M. Schahfer Units 14 and 15 (375 tons
SO<INF>2</INF> and 2,429 tons NO<INF>X</INF>); AES--Petersburg Unit 1
and 2 (1,412 tons SO<INF>2</INF> and 2,773 tons NO<INF>X</INF>);
SIGECO--A.B. Brown Units 1 and 2 (3,527 tons SO<INF>2</INF> and 2,112
tons NO<INF>X</INF>); and Lehigh Cement--Mitchell Kilns 1, 2, and 3
(700 tons SO<INF>2</INF> and 1,800 tons NO<INF>X</INF>).
---------------------------------------------------------------------------
\39\ 2018 CAMPD and 2018 Indiana Emissions Inventory Summary
Data are available in the docket and at <a href="https://campd.epa.gov/">https://campd.epa.gov/</a>;
<a href="https://www.in.gov/idem/airquality/reporting/emissions-summary-data/">https://www.in.gov/idem/airquality/reporting/emissions-summary-data/</a>.
---------------------------------------------------------------------------
For the selected EGUs continuing to operate, IDEM appropriately
examined the facilities for existing effective controls, trends in
SO<INF>2</INF> and NO<INF>X</INF> emissions, and LADCO's 2028 projected
emissions in determining that a four-factor analysis would not likely
result in the conclusion that further controls are necessary for
reasonable progress. In evaluating IDEM's reasoning, EPA also
considered trends in annual emissions and emission rates from 2018--
2023 CAMPD, emission limits in current title V permits, and the fact
that the projected 2028 visibility conditions for Class I areas
influenced by emissions from Indiana sources are below the URP in 2028.
The EGUs continuing to operate include: AEP--Rockport Boiler MB1 and
MB2; Duke--Gibson Units 1, 2, 3, 4, 5; AES--Petersburg Units 3, 4;
IKEC--Clifty Creek Units 1, 2, 3, 4, 5, 6; Duke--Cayuga Units 1, 2;
Alcoa--Warrick Power Plant Unit 4; SIGECO--F.B. Culley Units 2, 3;
Hoosier Energy--Merom Units 1SG1, 2SG1; and NIPSCO--R.M. Schahfer Units
16A, 16B, 17, 18. As summarized below, IDEM adequately documented that
these EGUs are effectively controlled for SO<INF>2</INF> and
NO<INF>X</INF> for the second implementation period in determining that
a full four-factor analysis would likely result in the conclusion that
no further controls are necessary for reasonable progress.
<bullet> AEP--Rockport Boiler MB1 and MB2: The SO<INF>2</INF> and
NO<INF>X</INF> emission limits and plant-wide tonnage caps are in a
Federal consent decree,\40\ SO<INF>2</INF> emission rates are below the
0.2 pounds per million British thermal units (lbs/MMBtu) for coal-fired
EGUs in MATS, and NO<INF>X</INF> emission rates are below the 0.08 lbs/
MMBtu level for units with selective catalytic reduction (SCR) under
the Federal ``Good Neighbor Plan''.\41\
---------------------------------------------------------------------------
\40\ Fifth Joint Modification To Consent Decree with the United
States District Court for the Southern District of Ohio in the
lawsuit entitled United States, et al. v. American Electric Power
Service Corp., et al., Civil Action Nos. 99-1182 (EAS) and 99-1250
(EAS), (AEP Consent Decree). The AEP Consent Decree is available in
the docket and at <a href="https://www.epa.gov/sites/default/files/documents/americanelectricpower-cd_1.pdf">https://www.epa.gov/sites/default/files/documents/americanelectricpower-cd_1.pdf</a>. See also 84 FR 26705, June 7, 2019.
\41\ Federal ``Good Neighbor Plan'' for the 2015 Ozone National
Ambient Air Quality Standards,'' Final Rule, 88 FR 36654, June 5,
2023. On October 29, 2024, EPA issued a final rule to
administratively stay the effectiveness of the Good Neighbor Plan's
requirements for all sources covered by that rule as promulgated
where an administrative stay was not already in place, including
Indiana. 89 FR 87960, November 6, 2024.
---------------------------------------------------------------------------
<bullet> Duke--Gibson Units 1, 2, 3, 4, and 5: The SO<INF>2</INF>
emission rates for all units are below the MATS, NO<INF>X</INF>
emission rates are below the 0.08 lbs/MMBtu level for units with SCR
under the Good Neighbor Plan, and the flue gas desulfurization (FGD)
and SCR systems achieve high control efficiencies.
<bullet> AES--Petersburg Units 3 and 4: The FGD systems achieve
high percentages of SO<INF>2</INF> control efficiency, actual
SO<INF>2</INF> emission rates for both units are below the MATS, and
SO<INF>2</INF> and NO<INF>X</INF> emission caps and limits are in place
under a 2020 Federal consent decree.
<bullet> IKEC--Clifty Creek Units 1, 2, 3, 4, 5, and 6: The FGD
systems achieve 98 percent control efficiency, the SCR and OFA systems
achieve 70-90 percent control efficiency on an annual basis,
SO<INF>2</INF> limits are contained Indiana's SIP at 40 CFR 52.770(d),
actual SO<INF>2</INF> emission rates for all six units are below MATS,
and NO<INF>X</INF> emissions are progressively constrained on an annual
basis under the Revised CSAPR Update Rule. While NPS provided an
estimate for cost effectiveness of the addition of SCR to Unit 6 at
$6,100/ton of NO<INF>X</INF> removed, IDEM determined that additional
emission reductions through the addition of new emission control
equipment would not be cost-effective.
<bullet> Duke--Cayuga Units 1 and 2: The SO<INF>2</INF> emission
rates are below the MATS, and the FGD and SCR systems achieve control
efficiencies near 90 percent or more.
<bullet> Alcoa--Warrick Power Plant: Unit 4 is subject to BART
emission limitations from the first implementation period on a
pollutant specific basis and is currently operating controls to meet
those BART emission limits, SO<INF>2</INF> and NO<INF>X</INF> controls
are in place, and actual SO<INF>2</INF> emission rates are below MATS.
<bullet> SIGECO--F.B. Culley Units 2 and 3: Federally enforceable
SO<INF>2</INF> and NO<INF>X</INF> emission limits and conditions
regarding operation of the FGD and SCR control systems are contained in
the
[[Page 25954]]
Federal consent decree and in Indiana's SIP at 52.770(c)(190),
SO<INF>2</INF> emission rates are below the MATS, and the FGD system
achieves a control efficiency of 99 percent.
<bullet> Hoosier Energy--Merom Units 1SG1 and 2SG1: The FGD and SCR
control systems achieve greater than 90 percent control efficiency,
SO<INF>2</INF> emission rates are below MATS, and NO<INF>X</INF>
emission rates are below the 0.08 lbs/MMBtu level for units with SCR
under the Good Neighbor Plan.
<bullet> NIPSCO--R.M. Schahfer: Units 16A and 16B are natural gas
turbines emitting less than 1 tpy SO<INF>2</INF> and 17 tpy
NO<INF>X</INF>. For Units 17 and 18, FGD systems achieve 99 percent
control efficiency, SO<INF>2</INF> emission rates are below MATS, and
NO<INF>X</INF> emission rates are below 0.199 lbs/MMBtu for units with
low NO<INF>X</INF> burners (LNB) under the Good Neighbor Plan.
In addition to demonstrating that these EGUs are effectively
controlled for the second implementation period, Indiana's analysis of
emissions from 2007 to 2019 and projected emissions from 2028
projections, in addition to the CAMPD information from 2018 to 2023
that EPA considered along with control measures in Federal consent
decrees and title V permits, showed each unit had consistently
implemented their existing measures, had demonstrated declining trends
in total annual emissions at each facility, and emissions were not
projected to increase through 2028. Additionally, the projected 2028
visibility conditions for Class I areas influenced by emissions from
Indiana sources are below the URP in 2028.\42\ As such, IDEM adequately
demonstrated that additional measures for these units are not necessary
to make reasonable progress during the second implementation period.
---------------------------------------------------------------------------
\42\ See Indiana's 2021 Regional Haze SIP submission, Table 23-1
and appendix L.
---------------------------------------------------------------------------
Indiana's long-term strategy included Federal on-the-books and on-
the-way controls. Indiana did not rely on additional measures as part
of the long-term strategy to make reasonable progress in the second
planning period for the units that IDEM identified through its Q/d
source selection process. For the units no longer operating, emission
reductions have already taken place during the second implementation
period. For the EGUs continuing to operate, IDEM sufficiently
demonstrated that existing effective controls are in place as described
in the 2019 Guidance, section 3(f) in determining that a full four-
factor analysis would likely result in the conclusion that no further
controls are necessary for reasonable progress. IDEM's analysis of
emissions from 2007 to 2019 and 2028 projections, CAMPD information
from 2018 to 2023, limits contained in existing permits and Federal
consent decrees, and the fact that projected 2028 visibility conditions
for Class I areas influenced by emissions from Indiana sources are
below the URP in 2028 support IDEM's determination that additional
measures at these EGUs are not necessary to make reasonable progress
for the second implementation period.
For the nine non-EGU facilities, Indiana provided a thorough
analysis of existing measures or a full four-factor analysis that
appropriately followed the methods in the EPA Air Pollution Control
Cost Manual.\43\ IDEM documented the range of cost effectiveness for
control options considered technically feasible in the four-factor
analyses.
---------------------------------------------------------------------------
\43\ See EPA Air Pollution Control Cost Manual, available at
<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>.
Table 1--Estimated Cost Effectiveness of Control Options Evaluated
----------------------------------------------------------------------------------------------------------------
Facility Unit Control option Cost effectiveness
----------------------------------------------------------------------------------------------------------------
Alcoa--Warrick Operations............ Potlines 2 through 6... FGD.................... $16,800 per ton of SO2
Anode Baking Ring FGD.................... $45,000 per ton of SO2
Furnace and A-446 Dry
Alumina Scrubbers.
Burns Harbor......................... Battery Nos. 1 and 2... Spray Dryer Absorber $5,300-$6,300 per ton
(SDA). of SO2
Clean Coke Oven Gas Desulfurization........ $4,000 per ton of SO2
Export Line and Flare.
Power Station Boilers SDA.................... $16,100 to 42,000 per
Nos. 7 through 12. ton of SO2
Dry Sorbent Injection $8,800 to $16,700 per
(DSI). ton of SO2
Indiana Harbor East.................. 80'' Hot Strip Mill Ultra-low NOX Burners $6,900 to $9,100 per
Walking Beam Furnaces (ULNB). ton of NOX
Nos. 5 and 6.
Sinter Plant Windbox... SDA.................... $28,900 per ton of SO2
DSI.................... $38,200 per ton of SO2
Lone Star Industries--Greencastle.... DSI.................... $10,035 per ton to
remove 47 tons of SO2
per year
Selective Non-Catalytic $1,679 per ton to
Reduction. remove 685 tons of NOX
per year
U.S. Steel--Gary Works............... 84'' Hot Strip Mill LNB.................... $14,142/ton to reduce
Reheat Furnaces. 211 tons of NOX
Waste Heat Boiler Nos. LNB.................... $6,130 and $6,344 per
1 and 2. ton to reduce 58 and
56 tons of NOX per
year, respectively
SABIC Innovative Plastics--Mt. Vernon Co-generation Unit..... SCR.................... $25,691 per ton to
LLC. remove 101 tons of NOX
per year
Phosgene Carbonyl Wet Packed Tower $12,449 per ton to
Sulfide Vent Oxidizer Absorber. remove 542 tons of SO2
and Flare. per year
----------------------------------------------------------------------------------------------------------------
For the other units evaluated at the non-EGU facilities, the
analyses thoroughly demonstrated that no reasonable set of
SO<INF>2</INF> or NO<INF>X</INF> control measures were identified
beyond what is currently installed and operated as described in Section
3 of EPA's April 22, 2025 TSD.
The emission reductions that have already occurred during the
second implementation period at Duke--Gallagher, NIPSCO--R.M. Schahfer,
AES--Petersburg, SIGECO--A.B. Brown, and Lehigh Cement--Mitchell
represent permanent reductions in SO<INF>2</INF> and NO<INF>X</INF>
from Indiana sources that have reduced visibility impairment at
impacted Class I areas. These decreases in emissions represent over
7,000 tpy SO<INF>2</INF> and over 9,000 tpy NO<INF>X</INF> from all the
sources IDEM selected with Q/d greater than five based on 2018
emissions. With a relatively small potential for additional emission
reductions identified in the four-factor analyses compared to emission
reductions that
[[Page 25955]]
have already taken place, IDEM provided a reasoned basis for its
conclusions that pursuing additional emission reductions through the
addition of new emission control measures or emissions limitations is
not cost-effective for the second implementation period. The trends in
NO<INF>X</INF> and SO<INF>2</INF> emissions noted in IDEM's progress
report discussed below and its analysis of emissions from 2007 to 2019
and 2028 projections, along with the 2018 to 2023 emissions data
considered by EPA demonstrate how Indiana's long-term strategy will
continue to make significant emissions reductions during the second
implementation period. Indiana's SIP revision shows that these measures
will achieve substantial SO<INF>2</INF> and NO<INF>X</INF> emission
reductions beyond those included in its first implementation period.
The reductions in emissions that have already occurred during the
second implementation period, along with on-the-books and on-the-way
control measures, contribute to Indiana's emission reductions and the
associated visibility improvements at the affected Class I areas for
the second implementation planning period.
EPA proposes to find that Indiana has satisfied the requirements of
40 CFR 51.308(f)(2)(i) related to evaluating sources and determining
the emission reduction measures that are necessary to make reasonable
progress by applying the four statutory factors to sources in a control
analysis. Indiana's SIP submission reasonably applied the Q/d source
selection process in relying on the closest Class I area and the
emissions of SO<INF>2</INF> and NO<INF>X</INF>. IDEM examined a
reasonable set of sources, including sources identified by FLMs. In
addition, IDEM adequately explained its decision to focus on the two
pollutants--SO<INF>2</INF> and NO<INF>X</INF>--that currently drive
visibility impairment within the LADCO region. EPA proposes to find
that Indiana adequately supported its conclusions for its top-impacting
sources in determining that no additional controls are necessary for
reasonable progress in the second implementation period. EPA is basing
this proposed finding on the State's examination of its largest
operating EGU and non-EGU sources, particularly the State's
consideration of the four statutory factors, the projected 2028
visibility conditions for Class I areas influenced by emissions from
Indiana sources all being below the URP in 2028, the historical
emissions data, the emission reductions that have already taken place
during the second implementation period, and the current control
technologies.
5. Consultation With States
The consultation requirements of 40 CFR 51.308(f)(2)(ii), provide
that States must consult with other States that are reasonably
anticipated to contribute to visibility impairment in a Class I area to
develop coordinated emission management strategies containing the
emission reductions measures that are necessary to make reasonable
progress. The provisions of 40 CFR 51.308(f)(2)(ii)(A) and (B) require
States to consider the emission reduction measures identified by other
States as necessary for reasonable progress and to include agreed upon
measures in their SIPs, respectively. The provisions of 40 CFR
51.308(f)(2)(ii)(C) speak to what happens if States cannot agree on
what measures are necessary to make reasonable progress. States may
satisfy the requirement of 40 CFR 51.308(f)(2)(ii) to engage in
interstate consultation with other States that have emissions that are
reasonably anticipated to contribute to visibility impairment in a
given Class I area under the auspices of intra- and inter-RPO
engagement.
Although Indiana has no mandatory Class I Federal areas within its
borders, Indiana has previously been shown to have sources with
emissions that impact visibility at downwind Class I Federal areas.
Indiana consulted with other States to develop a coordinated emission
management approach to its regional haze SIP and to address Indiana's
impact on nearby Class I areas. IDEM participated in the LADCO and
inter-RPO processes which developed the technical information needed
for such coordinated strategies.
Indiana participated in the LADCO Regional Haze Technical Workgroup
meetings with other LADCO States, FLMs, and EPA Region 5. Indiana also
consulted with other States and Tribes, receiving and responding to
letters \44\ from Arkansas, Missouri, Metro 4/SESARM/VISTAS,\45\ MANE-
VU,\46\ Arkansas, Missouri. IDEM replied with emissions analysis and
modeling results to demonstrate Indiana is meeting the State's regional
haze obligations to the surrounding States with Class I areas and that
no further analysis is necessary for the sources identified by the
States and RPOs. IDEM did not receive any replies disagreeing with
their responses. Section 4 of EPA's April 22, 2025 TSD provides a
detailed summary of Indiana's consultation with States.
---------------------------------------------------------------------------
\44\ See Section 3.4, 23, and appendix K and AA of Indiana's
2021 Regional Haze SIP submittal.
\45\ Metro 4/SESARM/VISTAS refers to the Southeastern States Air
Resources Managers, Inc. (SESARM) and the Visibility Improvement
State and Tribal Association of the Southeast (VISTAS) as the RPO
for Alabama, Florida, Georgia, Kentucky, Mississippi, North
Carolina, South Carolina, Tennesse, Virginia, West Virginia, the
Eastern Band of Cherokee Indians, and Knox County, Tennessee
(representing the 17 Southeastern local air agencies).
\46\ The Mid-Atlantic/Northeast Visibility Union (MANE-VU) is
the RPO for the Northeastern and Mid-Atlantic states and Tribal
governments, which include Connecticut, Delaware, the District of
Columbia, Maine, Maryland, Massachusetts, New Hampshire, New Jersey,
New York, Pennsylvania, Penobscot Indian Nation, Rhode Island, St.
Regis Mohawk Tribe, and Vermont.
---------------------------------------------------------------------------
EPA proposes to find that Indiana has satisfied the consultation
requirements of 40 CFR 51.308(f)(2)(ii). Indiana has met the
requirements of 40 CFR 51.308(f)(2)(ii)(A) and (B) with its
participation in the LADCO consultation process plus its individual
consultation meetings with contributing States. There were no
disagreements with another State; therefore, 40 CFR 51.308(f)(2)(ii)(C)
does not apply to Indiana.
The requirements of 40 CFR 51.308(f)(2)(iii) provide that a State
must document the technical basis for its decision making to determine
the emission reductions measures that are necessary to make reasonable
progress. The documentation requirement of 40 CFR 51.308(f)(2)(iii)
provides that States may meet their obligations to document the
technical bases on which they are relying to determine the emission
reductions measures that are necessary to make reasonable progress
through an RPO, as long as the process has been ``approved by all State
participants.'' Indiana adequately documented the technical basis,
including the modeling, monitoring, engineering, costs, and emissions
information that was relied on in determining the emission reduction
measures that are necessary to make reasonable progress.
For modeling, IDEM documented the modeling done by LADCO to
determine visibility projections and contributions to impairment at the
Class I areas. Indiana included justification for the 2016 base year
selection and the 2028 emission projections based on ERTAC forecasts
and state-reported changes.
For monitoring, IDEM described how ambient air quality monitoring
data were analyzed to produce a conceptual understanding of the air
quality problems contributing to haze as well as to project visibility
conditions in 2028 through LADCO's modeling and EPA's Updated 2028
Visibility Air Quality Modeling. IDEM noted that LADCO relied upon the
IMPROVE monitoring data to track the chemical composition
[[Page 25956]]
of PM<INF>2.5</INF> in haze at Class I areas in the LADCO region, which
included ammonium nitrate, ammonium sulfate, elemental carbon, organic
carbon, sea salt, and inorganic soil. IDEM also documented IMPROVE
monitoring data for several Class I areas from the 2000-2004, 2009-
2013, 2014-2018 monitored baselines along with graphs depicting their
respective glidepaths and monitored visibility for the 20 percent most
impaired days on an annual basis over the same time period.
For emissions information, IDEM provided data for 2007 through
2019, the most recent data years available at the time, from various
sources for each unit screened in using Indiana's Q/d source selection
threshold. Emissions data were obtained from EPA's Emissions Inventory
System, CAMPD, and the National Emissions Inventory (NEI).
Additionally, EPA considered 2011-2022 information from Indiana's
Emissions Summary Data and 2018-2022 emissions from CAMPD. Data from
2016 for annual emissions of NO<INF>X</INF>, SO<INF>2</INF>,
PM<INF>2.5</INF>, and NH<INF>3</INF> that was used in LADCO's modeling
relied upon the 2016 inventory developed by the National Emissions
Inventory Collaborative described above as well as forecasts from ERTAC
with state-reported changes to EGUs through 2020. The pollutants
inventoried by Indiana for the photochemical modeling included
NO<INF>X</INF>, SO<INF>2</INF>, VOCs, PM<INF>2.5</INF>, and
PM<INF>10</INF> data collected through Indiana's emissions reporting
rules. Since ammonia emissions are not reported to Indiana, modeled
estimates were provided by LADCO.
For engineering and costs, Indiana provided site-specific four-
factor analyses that evaluated potential engineering designs and costs
for various NO<INF>X</INF> and SO<INF>2</INF> emission control systems
for the nine non-EGU facilities as previously mentioned.
EPA proposes to find that such documentation of the technical basis
of the long-term strategy, including the modeling, monitoring,
engineering, costs, and emissions information discussed above,
satisfies the requirements of 40 CFR 51.308(f)(2)(iii).
The provisions of 40 CFR 51.308(f)(2)(iii) require that the
emissions information considered to determine the measures that are
necessary to make reasonable progress include information on emissions
for the most recent year for which the State has submitted triennial
emissions data to EPA (or a more recent year), with a 12-month
exemption period for newly submitted data. As previously mentioned
above, IDEM participated in the development of technical analyses,
including emission inventory information, by LADCO and its member
States, and is relying in part on those analyses to satisfy the
emission inventory requirements. Emissions for the 2016 base year and
the 2028 projected year used in LADCO's modeling address elements of 40
CFR 51.308(f)(6)(v) of the Regional Haze Rule, which requires that
States provide recent and future year emissions inventories of
pollutants anticipated to contribute to visibility impairment in any
Class I areas. Indiana's 2021 Regional Haze SIP revision for the second
implementation period also included 2017 NEI emission data, which
corresponds to the year of the most recent triennial NEI at the time of
Indiana's 2021 Regional Haze SIP submission, as required under 40 CFR
51.308(f)(2)(iii) of the Regional Haze Rule. Based on IDEM's
consideration and analysis of the 2017 emission data in its SIP
submission, EPA proposes to find that Indiana has satisfied the
emissions information requirement in 40 CFR 51.308(f)(2)(iii).
6. Five Additional Factors
In addition to the four statutory factors, States must also
consider the five additional factors listed in 40 CFR 51.308(f)(2)(iv)
in developing their long-term strategies. EPA proposes to find that
Indiana adequately considered those factors in developing this
submission.
As required by 40 CFR 51.308(f)(2)(iv)(A), Indiana considered
emission reductions due to ongoing air pollution control programs. IDEM
documented significant emission reductions based on current emission
control strategies at its sources that have reduced visibility
impairment at all surrounding Class I areas. IDEM noted ongoing Federal
emission control programs that have reduced and will continue to reduce
visibility-impairing pollutants from Indiana point sources, as well as
on-road and non-road mobile sources, in the second implementation
period. For point sources, these programs included Federal provisions
for title V permitting actions; Boiler MACT; Mercury and Air Toxics
Standards for power plants; Data Requirements Rule for the 2010
SO<INF>2</INF> NAAQS; and Revised CSAPR Update. For on-road mobile
sources, Indiana cited to Federal regulations for the Tier 2 Motor
Vehicle Emissions and Gasoline Standards Rule, Tier 3 Motor Vehicle
Emission and Fuel Standards, and Heavy-Duty Diesel Engine and Highway
Diesel Fuel Rule. For non-road mobile sources, IDEM cited to Federal
regulations for the Tier 4 Nonroad Engines and Diesel Fuel Rule.
As required by 40 CFR 51.308(f)(2)(iv)(B), Indiana's consideration
of measures to mitigate the impacts of construction activities in its
SIP submission referred to the State's title V permit program as well
as LADCO's inclusion of building construction, road construction,
agricultural dust, and road dust in the modeling, which identified
contributions to visibility impairment for consideration by the States.
Pursuant to 40 CFR 51.308(f)(2)(iv)(C), Indiana's SIP submission
addressed schedules for source retirements and replacements.
In considering smoke management for prescribed burns as required in
40 CFR 51.308(f)(2)(iv)(D), Indiana's Open Burning Rule at 326 IAC 4-1
addresses open burning, including prescribed burns used for
agricultural and wildland vegetation management purposes. Under 326 IAC
4-1-3, burning of vegetation for agricultural maintenance purposes is
exempt from the open burning rules on agricultural land, farms,
orchards, nursery, tree farms, cemeteries, and drainage ditches.
Burning of natural growth for the purpose of land management, such as
wildlife habitat maintenance, forestry purposes, natural area
management, and ecosystem management generally requires IDEM approval.
The exceptions are for burning conducted on properties owned by the
Indiana Department of Natural Resources, municipal or county
governments, the US Department of Interior, the US Department of
Agriculture, or USFS. Indiana's rules provide that such prescribed
burns are not allowed during unfavorable meteorological conditions,
including high winds, temperature inversions, air stagnation, or when a
pollution alert or ozone action day has been declared. To ensure smoke
from such activities is accounted for in the visibility projections,
IDEM noted that LADCO's modeling included a sector for wild and
prescribed fires.
As required by 40 CFR 51.308(f)(2)(iv)(E), Indiana considered the
anticipated net effect on visibility improvements due to projected
changes in emissions from point, area, and mobile sources during the
second implementation period addressed by the long-term strategy. The
visibility improvement expected during the second implementation period
was estimated using LADCO's 2016 base year and 2028 future year
inventory components to simulate 2016 and 2028 air quality. As
described above, for EGUs, projected changes for 2028
[[Page 25957]]
emissions in LADCO's modeling platform were based on ERTAC forecasts
and state-reported changes. For most other emission sectors, LADCO
relied upon EPA's 2016 and 2028 inventory estimates for projected
changes in sectors such as agriculture, on-road and non-road mobile,
rail, commercial marine, point and nonpoint oil and gas, residential
wood combustion, wild and prescribed fires, and Mexico and Canada
anthropogenic emissions. The projected changes in EPA's 2016 and 2028
inventory estimates take into account Federal on-the-books controls
such as those listed in Indiana's long-term strategy, above.
IDEM also demonstrated that visibility conditions in the LADCO
Class I Areas have shown continued improvement relative to baseline
conditions. As depicted in LADCO's 2021 TSD, 2016 visibility impairment
conditions at the LADCO Class I Areas on the 20 percent most impaired
days as well as the 20 percent clearest days were below their
respective glidepaths. By the end of the second implementation period
in 2028, both LADCO's projections and EPA's Updated 2028 Visibility Air
Quality Modeling show 2028 visibility conditions will remain below the
URP glidepaths for the LADCO Class I Areas.
After weighing the four-factor analyses and the five additional
required factors, Indiana determined that the existing emission
controls for the sources identified above IDEM's Q/d threshold are
effective for the second implementation period and that additional
measures are not necessary to meet second implementation period
regional haze SIP requirements. IDEM's process for selecting sources
for four-factor analyses represented 81 percent of the total
SO<INF>2</INF> and NO<INF>X</INF> emissions for all sources reporting
under 326 IAC 2-6, including 85 percent of SO<INF>2</INF> and 77
percent of NO<INF>X</INF>. IDEM provided an analytical means for
refining the list of sources selected by evaluating EGUs and non-EGUs
for demonstration of existing effective controls or four-factor
analysis. For the add-on controls evaluated for the units selected for
four-factor analyses, Indiana determined that the controls evaluated
were not cost effective to achieve emission reductions during the
second implementation period. IDEM reflected upon the steady and
significant improvement in visibility at each of the Class I areas
impacted by sources in Indiana and noted that LADCO's modeling shows
continued improvement with 2028 projections below their URP glidepaths
in 2028. As discussed under the progress report elements below, from
2007 to 2019, SO<INF>2</INF> emissions from all Indiana EGUs decreased
by 210,180 tons or 81 percent while NO<INF>X</INF> emissions decreased
by 46,360 tons or 50 percent. The decreasing trend continues with the
permanent emission reductions that have already occurred during the
second implementation period, representing over 7,000 tpy of
SO<INF>2</INF> and over 9,000 tpy of NO<INF>X</INF> from all the
sources identified by IDEM's Q/d selection process based on 2018
emissions.
Given all these factors, Indiana demonstrated that Federal on-the-
books and on-the-way controls are sufficient to make reasonable
progress in the second implementation period. EPA proposes to find that
Indiana reasonably considered and satisfied the requirements for each
of the five additional factors in 40 CFR 51.308(f)(2)(iv) in developing
its long-term strategy.
F. RPGs
The provisions of 40 CFR 51.308(f)(3) contain the requirements
pertaining to RPGs for each Class I area. Under 40 CFR 51.308(f)(3)(i),
a State, in which a mandatory Class I area is located, is required to
establish RPGs--one each for the most impaired and clearest days--
reflecting the visibility conditions that will be achieved at the end
of the implementation period as a result of the emission limitations,
compliance schedules and other measures required under paragraph (f)(2)
to be in States' long-term strategies, as well as implementation of
other CAA requirements. The long-term strategies as reflected by the
RPGs must provide for an improvement in visibility on the most impaired
days relative to the baseline period and ensure no degradation on the
clearest days relative to the baseline period. The provisions of 40 CFR
51.308(f)(3)(ii) apply in circumstances in which a Class I area's RPG
for the most impaired days represents a slower rate of visibility
improvement than the uniform rate of progress calculated under 40 CFR
51.308(f)(1)(vi). Under 40 CFR 51.308(f)(3)(ii)(A), if the State in
which a mandatory Class I area is located establishes an RPG for the
most impaired days that provides for a slower rate of visibility
improvement than the URP, the State must demonstrate that there are no
additional emission reduction measures for anthropogenic sources or
groups of sources in the State that would be reasonable to include in
its long-term strategy. The provisions of 40 CFR 51.308(f)(3)(ii)(B)
requires that if a State contains sources that are reasonably
anticipated to contribute to visibility impairment in a Class I area in
another State, and the RPG for the most impaired days in that Class I
area is above the URP, the upwind State must provide the same
demonstration. Because Indiana has no Class I areas within its borders
to which the requirements of the visibility protection program apply in
40 CFR part 81, subpart D, Indiana is subject only to 40 CFR
51.308(f)(3)(ii)(B), but not 40 CFR 51.308(f)(3)(i) or (f)(3)(ii)(A).
Under 40 CFR 51.308(f)(3)(ii)(B), a State that contains sources
that are reasonably anticipated to contribute to visibility impairment
in a Class I area in another State for which a demonstration by the
other State is required under 40 CFR 51.308(f)(3)(ii)(B) must
demonstrate that there are no additional emission reduction measures
that would be reasonable to include in its long-term strategy. Section
23 of Indiana's SIP submission shows that at the Class I areas impacted
by emissions from Indiana, the 2028 projected visibility impairment is
not above the adjusted URP glidepaths for the 20 percent most impaired
days and ensures no degradation on the 20 percent clearest days.
Therefore, EPA proposes that the demonstration requirement under 40 CFR
51.308(f)(3)(ii)(B) as it pertains to these areas is not triggered.
EPA proposes to determine that Indiana has satisfied the applicable
requirements of 40 CFR 51.308(f)(3) relating to RPGs.
G. Monitoring Strategy and Other Implementation Plan Requirements
The requirements of 40 CFR 51.308(f)(6) specify that each
comprehensive revision of a State's regional haze SIP must contain or
provide for certain elements, including monitoring strategies,
emissions inventories, and any reporting, recordkeeping and other
measures needed to assess and report on visibility. A main requirement
of this subsection is for States with Class I areas to submit
monitoring strategies for measuring, characterizing, and reporting on
visibility impairment. Compliance with this requirement may be met
through participation in the IMPROVE network.
As noted above, Indiana does not have any mandatory Class I Federal
areas located within its borders to which the requirements of the
visibility protection program apply in 40 CFR part 81, subpart D.
Therefore, 40 CFR 51.308(f)(6)(i), (ii), and (iv) do not apply.
The provisions of 40 CFR 51.308(f)(6)(iii) require States with no
Class I areas to include procedures by which monitoring data and other
[[Page 25958]]
information are used in determining the contribution of emissions from
within the State to regional haze visibility impairment at Class I
areas in other States. States with Class I areas must establish a
monitoring program and report data to EPA that is representative of
visibility at the Class I Federal areas. The IMPROVE network meets this
requirement. Indiana stated that, as a participant in LADCO, it
reviewed information about the chemical composition of baseline
monitoring data at Class I Federal areas in the LADCO region to
understand the sources of haze causing pollutants. IDEM does not
operate any monitoring sites under the Federal IMPROVE program and,
therefore, does not require approval of its monitoring network under
the Regional Haze Rule. IDEM relies upon participation in the IMPROVE
network as part of the State's monitoring strategy for regional haze to
review progress and trends in visibility at Class I areas that may be
affected by emissions from Indiana, for comprehensive periodic
revisions of this implementation plan, and for periodic reports
describing progress towards the RPGs for those areas.
The provisions of 40 CFR 51.308(f)(6)(v) require SIPs to provide
for a statewide inventory of emissions of pollutants that are
reasonably anticipated to cause or contribute to visibility impairment,
including emissions for the most recent year for which data are
available. In appendix O of its SIP submission, Indiana provided
statewide emission inventories for 2016-2018 in EPA's Emissions
Inventory System, as the most recent years available at the time of the
State's SIP submission. EPA's Emissions Inventory System is used to
develop the NEI, which provides for, among other things, a triennial
state-wide inventory of pollutants that are reasonably anticipated to
cause or contribute to visibility impairment. Indiana's SIP submission
at Section 5.13 and 5.15 also provided a summary of SO<INF>2</INF>,
NO<INF>X</INF>, PM<INF>2.5</INF>, VOCs, and NH<INF>3</INF> emissions
for 2016 that LADCO used in developing Q/d metrics and the 2016 base
year emissions inventory to project emissions to year 2028.
Additionally, as described in further detail under the progress report
elements, IDEM provided more recent data through 2019 from CAMPD to
depict trends in EGU emissions, which demonstrated an 81 percent
decrease in SO<INF>2</INF> emissions and a 50 percent decrease in
NO<INF>X</INF> emissions from 2007 to 2019.
The provisions of 40 CFR 51.308(f)(6)(v) also require States to
include estimates of future projected emissions and include a
commitment to update the inventory periodically. For future projected
emissions, Indiana relied on the LADCO modeling and analysis, which
estimated 2028 projected emissions of SO<INF>2</INF> and NO<INF>X</INF>
for specific facilities and emission groups in the LADCO States to
provide an assessment of expected future year air quality based on 2016
emissions as well as ERTAC and State forecasts. In addition, Indiana
annually updates its Emissions Summary Data for pollutants anticipated
to cause or contribute to visibility impairment in Class I areas to
support future regional haze progress reports and SIP revisions.
EPA proposes to find that Indiana has met the requirements of 40
CFR 51.308(f)(6) as described above, including through its continued
participation in LADCO, its own statewide Emissions Summary Data, and
its emissions reporting to EPA's Emissions Inventory System.
H. Requirements for Periodic Reports Describing Progress Towards the
RPGs
The provisions of 40 CFR 51.308(f)(5) require that periodic
comprehensive revisions of States' regional haze plans also address the
progress report requirements of 40 CFR 51.308(g)(1) through (5). The
purpose of these requirements is to evaluate progress towards the
applicable RPGs for each Class I area within the State and each Class I
area outside the State that may be affected by emissions from within
that State. The provisions of 40 CFR 51.308(g)(1) and (2) apply to all
States and require a description of the status of implementation of all
measures included in a State's first implementation period regional
haze plan and a summary of the emission reductions achieved through
implementation of those measures. The provisions of 40 CFR 51.308(g)(3)
apply only to States with Class I areas within their borders and
requires such States to assess current visibility conditions, changes
in visibility relative to baseline (2000-2004) visibility conditions,
and changes in visibility conditions relative to the period addressed
in the first implementation period progress report. The provisions of
51.308(g)(4) apply to all States and requires an analysis tracking
changes in emissions of pollutants contributing to visibility
impairment from all sources and sectors since the period addressed by
the first implementation period progress report. This provision further
specifies the year or years through which the analysis must extend
depending on the type of source and the platform through which its
emission information is reported. Finally, 40 CFR 51.308(g)(5), which
also applies to all States, requires an assessment of any significant
changes in anthropogenic emissions within or outside the State have
occurred since the period addressed by the first implementation period
progress report, including whether such changes were anticipated and
whether they have limited or impeded expected progress towards reducing
emissions and improving visibility.
Indiana's previous progress report, which was a 5-year progress
report submitted as a SIP revision for the first implementation period
on March 30, 2016,\47\ included NO<INF>X</INF> and SO<INF>2</INF>
emission inventories from CAMPD for 2005, 2009, 2013 for EGUs,
Indiana's Emissions Summary Data from 2005--2014 for contributing
sources, as well as inventories from 2005 and 2011 with 2018
projections for the sources categories of point, mobile, non-road, EGU,
and area sources. Based on Indiana's Emissions Summary Data covering
the period 2010 to 2014 for contributing sources, Indiana's 2016 5-year
progress report showed a decrease in SO<INF>2</INF> emissions by 28
percent and a decrease in NO<INF>X</INF> emissions by 12 percent. Over
the longer period from 2005 to 2014, IDEM documented a decrease in
SO<INF>2</INF> emissions by 64 percent and NO<INF>X</INF> emissions by
42 percent. See 82 FR 57694, December 7, 2017, and 83 FR 4847, February
2, 2018.
---------------------------------------------------------------------------
\47\ Indiana's March 30, 2016 Five-Year Progress Report is
available in the docket for EPA-R05-OAR-2016-0211.
---------------------------------------------------------------------------
For the second implementation period SIP submission, the 2019
Guidance recommends the progress report cover the first full year that
was not incorporated into the previous progress report through a year
that is as close as possible to the submission date of the SIP. 2019
Guidance at 55. Indiana's 2021 progress report covered the measures and
emissions reductions achieved from 2007 through 2019 in Indiana's
Emissions Summary Data, from 2016-2018 in EPA's Emissions Inventory
System for 2016-2018, and from 2007-2019 in CAMPD.
To address the progress report elements of 51.308(g)(1), Indiana
described the status of implementation of all measures in the long-term
strategy under its first implementation period regional haze plan.
These measures included several Federal measures, including CAIR and
its successor CSAPR, to which Indiana attributed the majority of
reductions in visibility-impairing emissions from the largest point-
source sector, EGUs, during the first implementation period. Federal
[[Page 25959]]
measures for point sources also included BART, MATS, Boiler MACT, and
the Data Requirements Rule for the 2010 SO<INF>2</INF> NAAQS.
Additional on-the-books control measures that generated further
emission reductions addressed mobile sources, such as Federal on-road
provisions under the Tier 2 Motor Vehicle Emissions and Gasoline
Standards Rule, Tier 3 Motor Vehicle Emissions and Fuel Standards, and
Heavy-Duty Diesel Engine and Highway Diesel Fuel Rule. Non-road Federal
measures for mobile sources included the Tier 4 Non-road Engines and
Diesel Fuel Rule.
As required by 40 CFR 51.308(g)(2), Indiana provided a summary of
the emission reductions achieved through the measures outlined above
from the first implementation period. As a result of these measures,
Indiana's Emissions Summary Data from 2007 to 2019 from across all
emission categories for all contributing sources, discussed more fully
below, show that Indiana's SO<INF>2</INF> emissions decreased by 90
percent from 836,260 to 82,677 tons, and NO<INF>X</INF> emissions
decreased by 65 percent from 271,556 to 94,002 tons. The most
significant emissions reductions from Indiana's SIP strategies resulted
from CAIR and CSAPR, MATS, and the Data Requirements Rule for the 2010
SO<INF>2</INF> NAAQS. CAMPD information shows that the EGU sector
experienced an 82 percent reduction in SO<INF>2</INF> from 263,766 tons
in 2014 to 47,834 tons in 2019, and a 50 percent reduction in
NO<INF>X</INF> from 95,284 tons in 2014 to 47,219 tons in 2019. Over
the longer period from 2007 to 2019, the EGUs reporting to CAMPD
achieved a 93 percent decrease in SO<INF>2</INF> from 655,139 to 47,834
tons as well as a 72 percent decrease in NO<INF>X</INF> from 168,916 to
47,219 tons. EPA proposes to find that Indiana has met the requirements
of 40 CFR 51.308(g)(1) and (2) because its SIP submission describes the
measures included in the long-term strategy from the first
implementation period, as well as the status of their implementation
and the emission reductions achieved through such implementation.
The provisions of 40 CFR 51.308(g)(3) do not apply because Indiana
has no mandatory Class I Federal areas within its borders as described
above.
To address 40 CFR 51.308(g)(4), Indiana documented the change in
emissions of SO<INF>2</INF> and NO<INF>X</INF> from all sources and
activities in the State. Graph 26-1 and appendix E of Indiana's SIP
submission documents changes in emissions of each of these pollutants
for biogenics, fires, non-point, non-road, on-road, and point source
categories for each year from 2007 through 2019, the most recent data
year available at the time for category level emissions in Indiana's
Emissions Summary Data. Indiana's tracking showed an overall decline in
emission reductions from 2007 to 2019, with a 90 percent reduction in
SO<INF>2</INF> and 65 percent reduction in NO<INF>X</INF>. IDEM also
provided data in appendix E of its SIP submission, as noted earlier,
with respect to EGUs that report to CAMPD from 2007 to 2019, the most
recent year available at the time, tracking the change in emissions and
chronicling the decrease in SO<INF>2</INF> by 93 percent from 655,139
to 47,834 tons as well as the decrease in NO<INF>X</INF> by 72 percent
from 168,916 to 47,219 tons. EPA proposes to find that Indiana has
satisfied the requirements of 40 CFR 51.308(g)(4) by tracking the
change in emissions of SO<INF>2</INF> and NO<INF>X</INF> from all
contributing sources since the first progress report.
To address 40 CFR 51.308(g)(5), Indiana documented significant
changes in anthropogenic emissions since the first implementation
period plan, within and outside of the State through LADCO and the
interstate consultation process, as an indicator of whether they were
anticipated and whether they limited or impeded progress in improving
visibility. Within the State, Indiana compared emissions from all
contributing sources in the State for each year from 2007 to 2019 to
identify changes in anthropogenic emissions, finding that overall
emissions significantly decreased for NO<INF>X</INF> and
SO<INF>2</INF>. As previously mentioned, these changes were anticipated
and attributed to CSAPR as it replaced CAIR, MATS, and the Data
Requirements Rule for the 2010 SO<INF>2</INF> NAAQS. With the
significant decreases in anthropogenic emissions of SO<INF>2</INF> and
NO<INF>X</INF> across all source categories, Indiana did not find any
changes in anthropogenic emissions within or outside the State that
occurred from 2007 to 2019 that would limit or impede progress in
reducing pollutant emissions and improving visibility. Indiana noted
that further improvements in visibility are anticipated with the
emission reductions to be realized from the Revised CSAPR Update along
with the emission reductions occuring during the second implementation
period as mentioned previously. The emissions trend data in Indiana's
SIP submission support an assessment that anthropogenic haze-causing
pollutant emissions in Indiana have decreased during the reporting
period and that changes in emissions have not limited or impeded
progress in reducing pollutant emissions and improving visibility. EPA
proposes to find that Indiana has met the requirements of 40 CFR
51.308(g)(5).
In section 28.1 of its SIP submission, Indiana committed to submit
a 5-year progress report for the second implementation period to
evaluate progress towards the reasonable progress goal for each
mandatory Class I Federal area located within and outside the State
that may be affected by emissions from within the State as required by
40 CFR 51.308(g). Indiana also committed to revising its regional haze
SIP and submitting it to EPA on schedule as required by 40 CFR
51.308(f).
I. Requirements for State and Federal Land Manager Coordination
CAA section 169A(d) requires States to consult with FLMs before
holding the public hearing on a proposed regional haze SIP and to
include a summary of the FLMs' conclusions and recommendations in the
notice to the public. In addition, 40 CFR 51.308(i)(2)'s FLM
consultation provision requires a State to provide FLMs with an
opportunity for consultation that is early enough in the State's policy
analyses of its emission reduction obligation so that information and
recommendations provided by the FLMs' can meaningfully inform the
State's decisions on its long-term strategy. If the consultation has
taken place at least 120 days before a public hearing or public comment
period, the opportunity for consultation will be deemed early enough.
Regardless, the opportunity for consultation must be provided at least
60 days before a public hearing or public comment period at the State
level. The requirements of 40 CFR 51.308(i)(2) also provide two
substantive topics on which FLMs must be provided an opportunity to
discuss with States: assessment of visibility impairment in any Class I
area and recommendations on the development and implementation of
strategies to address visibility impairment. In 40 CFR 51.308(i)(3),
States, in developing their implementation plans, are required to
include a description of how they addressed FLMs' comments.
In developing its SIP submission, IDEM participated with the FLMs
in an early consultation process regarding source selection as well as
a formal consultation process on a full draft regional haze SIP.
Additionally, through LADCO, IDEM consulted directly and indirectly
with the FLMs through emails, webinars, and conference calls early in
the SIP planning and
[[Page 25960]]
development process.\48\ On June 16, 2020, IDEM began the early
consultation process on the State's source selection process and
selection of sources for four-factor analyses. On May 18, 2021, Indiana
initiated a formal consultation process with the FLMs, providing a full
draft of its Regional Haze SIP and offering an opportunity for
consultation in person. IDEM initiated the early consultation process
more than 120 days before the first public comment period on Indiana's
plan and began the formal consultation process at least 60 days prior
to the first public comment period on Indiana's plan, as required by 40
CFR 51.308(i)(2). IDEM's response to the FLMs' comments from are
included as appendix U of Indiana's SIP submission as required by 40
CFR 51.308(i)(3). Section 2.2 of EPA's April 22, 2025 TSD provides more
information on the FLM consultation.
---------------------------------------------------------------------------
\48\ IDEM documented the FLM consultation process in Section 3.3
and appendix K and N of its SIP submission.
---------------------------------------------------------------------------
On September 28, 2021, Indiana announced the opportunity for public
comment and public hearing regarding the State's proposed SIP
submission for the second implementation period on IDEM's website for
public notices and for regional haze.\49\ The public notice included
the FLMs' comments in the proposed SIP submission. An in-person and
virtual public hearing was held on October 28, 2021.\50\ The public
comment period ended November 15, 2021. Following the public comment
period, Indiana submitted its SIP revision to EPA on December 29, 2021.
---------------------------------------------------------------------------
\49\ IDEM's website for public notices is <a href="https://www.in.gov/idem/public-notices/">https://www.in.gov/idem/public-notices/</a> and <a href="https://www.in.gov/idem/sips/regional-haze/">https://www.in.gov/idem/sips/regional-haze/</a>
for regional haze.
\50\ IDEM documented the verbal comments received during the
public hearing in the transcript contained in appendix Z of its SIP
submission. IDEM also included the written public comments along
with an index in appendix Ya and Yb of its SIP submission. In
addition, IDEM summarized the comments and included IDEM's responses
in appendix V.
---------------------------------------------------------------------------
IDEM considered input from the FLMs and the public that were
provided during the FLM consultation period and public notice period
when finalizing this SIP revision.
As required by 40 CFR 51.308(i)(4), Indiana committed to continue
consultation with States and FLMs on the development and review of any
future plan revisions and progress reports, as well as other programs
having the potential to contribute to visibility impairment in the
mandatory Class I areas. Given IDEM's actions recounted above and in
EPA's April 22, 2025, TSD, EPA proposes to find that Indiana has
satisfied the requirements of 40 CFR 51.308(i) to consult with the FLMs
on its regional haze SIP for the second implementation period.
V. Proposed Action
EPA proposes to approve Indiana's December 29, 2021, SIP submission
as satisfying the regional haze requirements for the second
implementation period contained in 40 CFR 51.308(f).
VI. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the CAA and applicable
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, EPA's role is to approve State choices,
provided that they meet the criteria of the CAA. Accordingly, this
action merely approves State law as meeting Federal requirements and
does not impose additional requirements beyond those imposed by State
law. For that reason, this action:
<bullet> Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
<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, Incorporation by
reference, Nitrogen oxides, Ozone, Particulate matter, Sulfur oxides.
Dated: June 6, 2025.
Anne Vogel,
Regional Administrator, Region 5.
[FR Doc. 2025-11259 Filed 6-17-25; 8:45 am]
BILLING CODE 6560-50-P
</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>Indexed from Federal Register on June 18, 2025.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.