[Federal Register Volume 90, Number 203 (Thursday, October 23, 2025)]
[Proposed Rules]
[Pages 48481-48502]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-19637]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 52
[EPA-R09-OAR-2025-0101; FRL-12600-01-R9]
Approval and Promulgation of Air Quality Implementation Plans;
Nevada; Regional Haze State Implementation Plan for the Second
Implementation Period
AGENCY: Environmental Protection Agency (EPA).
ACTION: Proposed rule.
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SUMMARY: The Environmental Protection Agency (EPA) is proposing to
approve portions of the regional haze state implementation plan (SIP)
revisions submitted by the Nevada Division of Environmental Protection
(NDEP) on August 12, 2022 (``2022 Nevada Regional Haze Plan'') and on
May 28, 2025 (``2025 SIP Supplement''), as satisfying applicable
requirements under the Clean Air Act (CAA) and the EPA's Regional Haze
Rule (RHR) for the program's second implementation period. These
revisions address the requirement that states must periodically revise
their long-term strategies for making reasonable progress towards the
national goal of preventing any future, and remedying any existing,
anthropogenic impairment of visibility, including regional haze, in
mandatory Class I Federal areas. The revisions also address other
applicable requirements for the second implementation period of the
regional haze program. The EPA is taking this action pursuant to CAA
sections 110 and 169A.
DATES: Written comments must be received on or before November 24,
2025.
(1) Addresses: Submit your comments, identified by Docket ID No.
EPA-R09-OAR-2025-0101 at https://www.regulations.gov. For comments
submitted at Regulations.gov, follow the online instructions for
submitting comments. Once submitted, comments cannot be edited or
removed from Regulations.gov. The EPA may publish any comment received
to its public docket. Do not submit electronically any information you
consider to be confidential business information (CBI) or other
information whose disclosure is restricted by statute. Multimedia
submissions (audio, video, etc.) must be accompanied by a written
comment. The written comment is considered the official comment and
should include discussion of all points you wish to make. The EPA will
generally not consider comments or comment contents located outside of
the primary submission (i.e., on the web, cloud, or other file sharing
system). For additional submission methods, please contact the person
identified in the FOR FURTHER INFORMATION CONTACT section. For the full
EPA public comment policy, information about CBI or multimedia
submissions, and general guidance on making effective comments, please
visit https://www.epa.gov/dockets/commenting-epa-dockets. If you need
assistance in a language other than English or if you are a person with
a disability who needs a reasonable accommodation at no cost to you,
please contact the person identified in the FOR FURTHER INFORMATION
CONTACT section.
[[Page 48482]]
FOR FURTHER INFORMATION CONTACT: Emily Millar, Geographic Strategies &
Modeling Section (ARD-2-2), Planning & Analysis Branch, Air & Radiation
Division, EPA Region IX, 75 Hawthorne Street, San Francisco, CA 94105,
telephone number: (213) 244-1882, email address: [email protected].
SUPPLEMENTARY INFORMATION: Throughout this document, ``we,'' ``us,''
and ``our'' refer to the EPA.
Table of Contents
I. What action is the EPA proposing?
II. Background and Requirements for Regional Haze Plans
A. Regional Haze Background
B. Roles of Agencies in Addressing Regional Haze
III. Requirements for Regional Haze Plans for the Second
Implementation Period
A. Long-Term Strategy for Regional Haze
B. Reasonable Progress Goals
C. Monitoring Strategy and Other State Implementation Plan
Requirements
D. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
E. Requirements for State and Federal Land Manager Coordination
IV. The EPA's Evaluation of Nevada's Regional Haze Submissions for
the Second Implementation Period
A. Background on Nevada's First Implementation Period SIP
Submission
B. Nevada's Second Implementation Period SIP Submissions and the
EPA's Evaluation
C. Identification of Class I Areas
D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
E. Long-Term Strategy for Regional Haze
F. Reasonable Progress Goals
G. Additional Monitoring To Assess Reasonably Attributable
Visibility Impairment
H. Monitoring Strategy and Other Implementation Plan
Requirements
I. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
J. Requirements for State and Federal Land Manager Coordination
V. Proposed Action
VI. Incorporation by Reference
VII. Statutory and Executive Order Reviews
I. What action is the EPA proposing?
On August 12, 2022, NDEP submitted the 2022 Nevada Regional Haze
Plan, titled ``Nevada Regional Haze State Implementation Plan for the
Second Planning Period'' as a revision to the Nevada SIP to address
regional haze for the second implementation period.\1\ NDEP made this
SIP submission to satisfy the requirements of the CAA's regional haze
program pursuant to CAA sections 169A and 169B and 40 CFR 51.308. The
EPA found this submission complete on August 16, 2022.\2\ On July 27,
2023, NDEP withdrew the reasonable progress determinations for Tracy
Generating Station's Pi[ntilde]on Pine Unit (also known variously as
Tracy Unit 4 and Tracy Unit 7) and North Valmy Generating Station's
Unit 1 and Unit 2.\3\ On May 28, 2025, NDEP submitted the 2025 SIP
Supplement, titled ``Nevada Regional Haze Revision to the State
Implementation Plan for the Second Planning Period,'' which includes
revised reasonable progress determinations for those two sources.\4\
The 2025 Supplement also includes updated permits for three sources,
replacing those submitted as part of the 2022 Nevada Regional Haze
Plan.\5\ At this time the EPA is not proposing to act on the revised
reasonable progress determinations for Tracy Unit 7 (Pi[ntilde]on Pine
Unit 4) and North Valmy Generating Station's Unit 1 and Unit 2, which
were included in the 2025 SIP Supplement. However, the EPA is proposing
to find that the 2022 Nevada Regional Haze Plan, as revised by the July
27, 2023 partial withdrawal, and the permits submitted in appendix A of
the 2025 SIP Supplement, meets the applicable statutory and regulatory
requirements. Thus, we propose to approve the 2022 Nevada Regional Haze
Plan (excluding the portions withdrawn on July 27, 2023) and appendix A
(``Air Quality Permits Incorporated by Reference'') of the 2025
Supplement (collectively ``the Plan'') into the Nevada SIP.
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\1\ Letter dated August 12, 2022, from Greg Lovato,
Administrator, NDEP, to Martha Guzman, Regional Administrator, U.S.
Environmental Protection Agency Region 9 (submitted electronically
August 12, 2022).
\2\ Letter dated August 16, 2022, from Elizabeth Adams,
Director, Air and Radiation Division, EPA Region IX, to Greg Lovato,
Administrator, NDEP.
\3\ Letter dated July 27, 2023, from Jennifer L. Carr,
Administrator, NDEP, to Martha Guzman, Regional Administrator, U.S.
Environmental Protection Agency Region 9 (submitted electronically
August 2, 2023).
\4\ Letter dated May 23, 2025, from Jennifer L. Carr,
Administrator, NDEP, to Josh F.W. Cook, Regional Administrator, U.S.
Environmental Protection Agency Region 9 (submitted electronically
May 27, 2025).
\5\ 2025 SIP Supplement, appendix A.
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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.\6\ 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.\7\ The following is an
abbreviated history and background of the regional haze program and
2017 RHR as it applies to the current action.
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\6\ See 90 FR 13516 (March 24, 2025).
\7\ See 82 FR 3078 (January 10, 2017), located at https://www.federalregister.gov/documents/2017/01/10/2017-00268/protection-of-visibility-amendments-to-requirements-for-State-plans#h-16).
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A. Regional Haze Background
In the 1977 CAA Amendments, Congress created a program for
protecting visibility in the nation's mandatory Class I Federal areas,
which include certain national parks and wilderness areas.\8\ 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.''
\9\
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\8\ CAA 169A. 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.
\9\ CAA 169A(a)(1).
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Regional haze is visibility impairment that is produced by a
multitude of anthropogenic sources and activities which are located
across a broad geographic area and that emit pollutants that impair
visibility. Visibility impairing pollutants include fine and coarse
particulate matter (PM) (e.g., sulfates, nitrates, organic carbon,
elemental carbon, and soil dust) and their precursors (e.g., sulfur
dioxide (SO2), nitrogen oxides (NOX), and, in
some cases, volatile organic compounds (VOC) and ammonia
(NH3)). Fine particle precursors react in the atmosphere to
form PM2.5, which impairs visibility by scattering and
absorbing light. Visibility impairment reduces the perception of
clarity and color, as well as visible distance.\10\
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\10\ 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 it being
scattered and absorbed as it passes through the atmosphere.
Atmospheric light extinction (b\ext\) is a metric used for
expressing visibility and is measured in inverse megameters
(Mm-1). The formula for the deciview is 10 ln (b\ext\)/10
Mm-1). 40 CFR 51.301.
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To address regional haze visibility impairment, the 1999 RHR
established an iterative planning process that requires both states in
which Class I areas are located and states ``the emissions from which
may reasonably
[[Page 48483]]
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.\11\
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\11\ CAA 169A(b)(2). The RHR expresses the statutory requirement
for states to submit plans addressing out-of-state class I areas by
providing that states must address visibility impairment ``in each
mandatory Class I Federal area located outside the State that may be
affected by emissions from within the State.'' 40 CFR 51.308(d),
(f). See also 40 CFR 51.308(b), (f) (establishing submission dates
for iterative regional haze SIP revisions); 64 FR 35714, 35768 (July
1, 1999).
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On January 10, 2017, the EPA promulgated revisions to the RHR,
which apply for the second and subsequent implementation periods.\12\
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).
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\12\ 82 FR 3078 (January 10, 2017).
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B. Roles of Agencies in Addressing Regional Haze
Because the air pollutants and pollution affecting visibility in
Class I areas can be transported over long distances, successful
implementation of the regional haze program requires long-term,
regional coordination among multiple jurisdictions and agencies that
have responsibility for Class I areas and the emissions that impact
visibility in those areas. To address regional haze, states need to
develop strategies in coordination with one another, considering the
effect of emissions from one jurisdiction on the air quality in
another. Five regional planning organizations (RPOs), which include
representation from state and Tribal governments, the EPA, and FLMs,
were developed in the lead-up to the first implementation period to
address regional haze. RPOs evaluate technical information to better
understand how emissions from State and Tribal land impact Class I
areas across the country, pursue the development of regional strategies
to reduce emissions of particulate matter and other pollutants leading
to regional haze, and help states meet the consultation requirements of
the RHR.
The Western Regional Air Partnership (WRAP), one of the five RPOs,
is a collaborative effort of state governments, Tribal governments, and
various Federal agencies established to initiate and coordinate
activities associated with the management of regional haze, visibility,
and other air quality issues in the western corridor of the United
States. Member states (listed alphabetically) include: Alaska, Arizona,
California, Colorado, Idaho, Montana, Nevada, New Mexico, North Dakota,
Oregon, South Dakota, Utah, Washington, and Wyoming. The Federal
partner members of WRAP are the EPA, U.S. National Parks Service (NPS),
U.S. Fish and Wildlife Service (FWS), and U.S. Forest Service (USFS).
There are also 468 federally recognized Tribes within the WRAP region.
III. Requirements for Regional Haze Plans for the Second Implementation
Period
Under the CAA and the EPA's regulations, all 50 states, the
District of Columbia, and the U.S. Virgin Islands were required to
submit regional haze SIP revisions 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.\13\ 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 section 40 CFR 51.308(f)(1) through (3) generally
mirroring the order of the steps in the reasonable progress analysis
\14\ and (f)(4) through (6) containing additional, related
requirements. Broadly speaking, a state first must identify the Class I
areas within the state and determine the Class I areas outside the
state in which visibility may be affected by emissions from the state.
These are the Class I areas that must be addressed in the state's long-
term strategy.\15\ 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).\16\ 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.
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 emissions 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'' \17\ that states must consider in
developing their long-term strategies.\18\ A state evaluates potential
emissions 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.\19\
There are additional requirements in the rule, including FLM
consultation, that apply to all visibility protection SIPs and SIP
revisions.\20\
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\13\ CAA 169A(b)(2)(B).
\14\ The EPA explained in the 2017 RHR Revisions that we were
adopting new regulatory language in 40 CFR 51.308(f) that, unlike
the structure in 51.308(d), ``tracked the actual planning
sequence.'' 82 FR 3078, 3091 (January 10, 2017).
\15\ See 40 CFR 51.308(f), (f)(2).
\16\ See 40 CFR 51.308(f)(1).
\17\ 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.
\18\ See 40 CFR 51.308(f)(2).
\19\ 40 CFR 51.308(f)(2)-(3).
\20\ See, e.g., 40 CFR 51.308(i).
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A. Long-Term Strategy for Regional Haze
While states have discretion to choose any source selection
methodology that is reasonable, whatever choices they make should be
reasonably explained. To this end, 40 CFR 51.308(f)(2)(i) requires that
a state's SIP submission include ``a description of the criteria it
used to determine which sources or groups of sources it evaluated.''
The
[[Page 48484]]
technical basis for source selection, which may include methods for
quantifying potential visibility impacts such as emissions divided by
distance metrics, trajectory analyses, residence time analyses, and/or
photochemical modeling, must also be appropriately documented, as
required by 40 CFR 51.308(f)(2)(iii).
Once a state has selected the set of sources, the next step is to
determine the emissions reduction measures for those sources that are
necessary to make reasonable progress for the second implementation
period.\21\ This is accomplished by considering the four factors--``the
costs of compliance, the time necessary for compliance, and the energy
and non-air quality environmental impacts of compliance, and the
remaining useful life of any existing source subject to such
requirements.'' \22\ The EPA has explained that the four-factor
analysis is an assessment of potential emissions 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.'' \23\ Thus, for each source it has
selected for four-factor analysis,\24\ a state must consider a
``meaningful set'' of technically feasible control options for reducing
emissions of visibility impairing pollutants.\25\
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\21\ The CAA provides that, ``[i]n determining reasonable
progress there shall be taken into consideration'' the four
statutory factors. CAA 169A(g)(1). However, in addition to four-
factor analyses for selected sources, groups of sources, or source
categories, a state may also consider additional emissions reduction
measures for inclusion in its long-term strategy, e.g., from other
newly adopted, on-the-books, or on-the-way rules and measures for
sources not selected for four-factor analysis for the second
planning period.
\22\ CAA 169A(g)(1).
\23\ 82 FR 3078, 3091 (January 10, 2017).
\24\ ``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 at
3088 (January 10, 2017).
\25\ Id. at 3088 (January 10, 2017).
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The EPA has also explained that, in addition to the four statutory
factors, states have flexibility under the CAA and RHR to reasonably
consider visibility benefits as an additional factor alongside the four
statutory factors.\26\ Ultimately, while states have discretion to
reasonably weigh the factors and to determine what level of control is
needed, 40 CFR 51.308(f)(2)(i) provides that a state ``must include in
its implementation plan a description of . . . how the four factors
were taken into consideration in selecting the measure for inclusion in
its long-term strategy.''
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\26\ 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, p. 186.
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As explained above, 40 CFR 51.308(f)(2)(i) requires states to
determine the emissions reduction measures for sources that are
necessary to make reasonable progress by considering the four factors.
Pursuant to 40 CFR 51.308(f)(2), measures that are necessary to make
reasonable progress towards the national visibility goal must be
included in a state's long-term strategy and in its SIP. If the outcome
of a four-factor analysis is that an emissions reduction measure is
necessary to make reasonable progress towards remedying existing or
preventing future anthropogenic visibility impairment, that measure
must be included in the SIP.
The characterization of information on each of the factors is also
subject to the documentation requirement in 40 CFR 51.308(f)(2)(iii).
The reasonable progress analysis is a technically complex exercise, and
also a flexible one that provides states with bounded discretion to
design and implement approaches appropriate to their circumstances.
Given this flexibility, 40 CFR 51.308(f)(2)(iii) plays an important
function in requiring a state to document the technical basis for its
decision making so that the public and the EPA can comprehend and
evaluate the information and analysis the state relied upon to
determine what emissions reduction measures must be in place to make
reasonable progress. The technical documentation must include the
modeling, monitoring, cost, engineering, and emissions information on
which the state relied to determine the measures necessary to make
reasonable progress.
Additionally, the RHR at 40 CFR 51.3108(f)(2)(iv) separately
provides five ``additional factors'' \27\ that states must consider in
developing their long-term strategies: (1) Emissions reductions due to
ongoing air pollution control programs, including measures to address
reasonably attributable visibility impairment; (2) measures to reduce
the impacts of construction activities; (3) source retirement and
replacement schedules; (4) basic smoke management practices for
prescribed fire used for agricultural and wildland vegetation
management purposes and smoke management programs; and (5) the
anticipated net effect on visibility due to projected changes in point,
area, and mobile source emissions over the period addressed by the
long-term strategy.
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\27\ The five ``additional factors'' for consideration in 40 CFR
51.308(f)(2)(iv) are distinct from the four factors listed in CAA
section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states must
consider and apply to sources in determining reasonable progress.
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Because the air pollution that causes regional haze crosses state
boundaries, 40 CFR 51.308(f)(2)(ii) requires a state to consult with
other states that also have emissions that are reasonably anticipated
to contribute to visibility impairment in a given Class I area. If a
state, pursuant to consultation, agrees that certain measures (e.g., a
certain emissions limitation) are necessary to make reasonable progress
at a Class I area, it must include those measures in its SIP.\28\
Additionally, the RHR requires that states that contribute to
visibility impairment at the same Class I area consider the emissions
reduction measures the other contributing states have identified as
being necessary to make reasonable progress for their own sources.\29\
If a state has been asked to consider or adopt certain emissions
reduction measures, but ultimately determines those measures are not
necessary to make reasonable progress, that state must document in its
SIP submission the actions taken to resolve the disagreement.\30\ Under
all circumstances, a state must document in its SIP submission all
substantive consultations with other contributing states.\31\
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\28\ 40 CFR 51.308(f)(2)(ii)(A).
\29\ 40 CFR 51.308(f)(2)(ii)(B).
\30\ 40 CFR 51.308(f)(2)(ii)(C).
\31\ 40 CFR 51.308(f)(2)(ii)(C).
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B. Reasonable Progress Goals
Reasonable progress goals ``measure the progress that is projected
to be achieved by the control measures states have determined are
necessary to make reasonable progress based on a four-factor
analysis.'' \32\
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\32\ 82 FR 3078, 3091 (January 10, 2017).
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For the second implementation period, the RPGs are set for 2028.
RPGs are not enforceable targets.\33\ 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
[[Page 48485]]
degradation in visibility for the clearest days since the baseline
period.''
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\33\ 40 CFR 51.308(f)(3)(iii).
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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 emissions
reduction measures would be reasonable to include in its long-term
strategy.\34\ 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.''
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\34\ 40 CFR 51.308(f)(3)(ii).
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C. Monitoring Strategy and Other State Implementation Plan Requirements
Section 51.308(f)(6) requires states to have certain strategies and
elements in place for assessing and reporting on visibility. Individual
requirements under this section apply either to states with Class I
areas within their borders, states with no Class I areas but that are
reasonably anticipated to cause or contribute to visibility impairment
in any Class I area, or both. Compliance with the monitoring strategy
requirement may be met through a state's participation in the
Interagency Monitoring of Protected Visual Environments (IMPROVE)
monitoring network, which is used to measure visibility impairment
caused by air pollution at the 156 Class I areas covered by the
visibility program.\35\
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\35\ 40 CFR 51.308(f)(6), (f)(6)(i), (f)(6)(iv).
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All states' SIP submissions must provide for procedures by which
monitoring data and other information are used to determine the
contribution of emissions from within the state to regional haze
visibility impairment in affected Class I areas, as well as a statewide
inventory documenting such emissions.\36\ 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.\37\
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\36\ 40 CFR 51.308(f)(6)(ii), (iii), (v).
\37\ 40 CFR 51.308(f)(6)(vi).
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D. Requirements for Periodic Reports Describing Progress Towards the
Reasonable Progress Goals
Section 51.308(f)(5) requires a state's regional haze SIP revision
to address the requirements of paragraphs 40 CFR 51.308(g)(1) through
(5) so that the plan revision due in 2021 will serve also as a progress
report addressing the period since submission of the progress report
for the first implementation period. The regional haze progress report
requirement is designed to inform the public and the EPA about a
state's implementation of its existing long-term strategy and whether
such implementation is in fact resulting in the expected visibility
improvement.\38\ To this end, every state's SIP revision for the second
implementation period is required to assess changes in visibility
conditions and describe the status of implementation of all measures
included in the state's long-term strategy, including BART and
reasonable progress emissions reduction measures from the first
implementation period, and the resulting emissions reductions.\39\
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\38\ See 81 FR 26942, 26950 (May 4, 2016); 82 FR 3078, 3119
(January 10, 2017).
\39\ 40 CFR 51.308(g)(1) and (2).
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E. Requirements for State and Federal Land Manager Coordination
CAA section 169A(d) requires that before a state holds a public
hearing on a proposed regional haze SIP revision, it must consult with
the appropriate FLM or FLMs; pursuant to that consultation, the state
must include a summary of the FLMs' conclusions and recommendations in
the notice to the public. Consistent with this statutory requirement,
the RHR also requires that states ``provide the [FLM] with an
opportunity for consultation, in person and at a point early enough in
the State's policy analyses of its long-term strategy emission
reduction obligation so that information and recommendations provided
by the [FLM] can meaningfully inform the State's decisions on the long-
term strategy.'' \40\ For the EPA to evaluate whether FLM consultation
meeting the requirements of the RHR has occurred, the SIP submission
should include documentation of the timing and content of such
consultation. The SIP revision submitted to the EPA must also describe
how the state addressed any comments provided by the FLMs.\41\ 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.\42\
---------------------------------------------------------------------------
\40\ 40 CFR 51.308(i)(2).
\41\ 40 CFR 51.308(i)(3).
\42\ 40 CFR 51.308(i)(4).
---------------------------------------------------------------------------
IV. The EPA's Evaluation of Nevada's Regional Haze Submissions for the
Second Implementation Period
A. Background on Nevada's First Implementation Period SIP Submission
NDEP submitted its regional haze plan for the first implementation
period to the EPA on November 18, 2009. The requirements for regional
haze SIP submissions for the first implementation period are contained
in 40 CFR 51.308(d) and (e).\43\ On March 26, 2012, the EPA approved
all portions of the 2009 plan, but did not act on the BART
determination for Reid Gardner Generating Station (RGGS) for
NOX.\44\ On August 23, 2012, we partially approved and
partially disapproved this remaining portion of the plan. Specifically,
the EPA approved NDEP's selection of a NOX emissions limit
of 0.20 pounds per million British thermal units (lb/MMBtu) as BART for
RGGS Units 1 and 2. We disapproved two provisions of NDEP's BART
determination for NOX at RGGS: the NOX emissions
limit for Unit 3 and the compliance method for all three units. As a
result, the EPA promulgated a FIP, which replaced the disapproved SIP
provisions by establishing a BART emissions limit for NOX of
0.20 lb/MMBtu at Unit 3, and a 30-day averaging period for compliance
on a heat input-weighted basis across all three units.\45\ The EPA
later rescinded the RGGS FIP because RGGS Units 1-3 were permanently
decommissioned.\46\
---------------------------------------------------------------------------
\43\ 40 CFR 51.308(b).
\44\ 77 FR 17334 (March 26, 2012).
\45\ 78 FR 53033 (August 28, 2013).
\46\ 83 FR 54053 (October 26, 2018).
---------------------------------------------------------------------------
Pursuant to 40 CFR 51.308(g), NDEP was also responsible for
submitting a five-year progress report as a SIP revision for the first
implementation period, which it did on November 18, 2014. The EPA
approved the progress
[[Page 48486]]
report into the Nevada SIP on August 8, 2017.\47\
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\47\ 82 FR 37020, (August 8, 2017).
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B. Nevada's Second Implementation Period SIP Submissions and the EPA's
Evaluation
In accordance with CAA sections 169A and the RHR at 40 CFR
51.308(f), on August 12, 2022, NDEP submitted the 2022 Nevada Regional
Haze Plan to address its regional haze obligations for the second
implementation period, which runs through 2028. NDEP made the 2022
Nevada Regional Haze SIP submission available for public comment on
June 23, 2022. NDEP received and responded to public comments and
included the comments and responses to those comments in its
submission. On July 27, 2023, NDEP withdrew the reasonable progress
determinations for the Tracy Generating Station's Pi[ntilde]on Pine
Unit and North Valmy Generating Station's Unit 1 and Unit 2 and related
portions of the 2022 Nevada Regional Haze Plan.
On May 27, 2025, NDEP submitted the 2025 SIP Supplement that
includes the revised reasonable progress determinations. NDEP made the
2025 SIP Supplement available for public comment on February 28, 2025.
NDEP received and responded to public comments and included the
comments and responses to those comments in its submission.\48\ The
following sections describe the Plan, including analyses conducted by
the WRAP and Nevada's determinations based on those analyses, NDEP's
assessment of progress made since the first implementation period in
reducing emissions of visibility impairing pollutants, and the
visibility improvement progress at its Class I area and nearby Class I
areas. This notice also provides the EPA's evaluation of the Plan
against the requirements of the CAA and RHR for the second
implementation period of the regional haze program.
---------------------------------------------------------------------------
\48\ 2025 SIP Supplement, section 6.2 and appendix G.
---------------------------------------------------------------------------
C. Identification of Class I Areas
Section 169A(b)(2) of the CAA requires each state in which any
Class I area is located or ``the emissions from which may reasonably be
anticipated to cause or contribute to any impairment of visibility'' in
a Class I area to have a plan for making reasonable progress toward the
national visibility goal. The RHR implements this statutory requirement
at 40 CFR 51.308(f), which provides that each state's plan ``must
address regional haze in each mandatory Class I Federal area located
within the State and in each mandatory Class I Federal area located
outside the State that may be affected by emissions from within the
State,'' and (f)(2), which requires each state's plan to include a
long-term strategy that addresses regional haze in such Class I areas.
The EPA concluded in the 1999 RHR that ``all [s]tates contain
sources whose emissions are reasonably anticipated to contribute to
regional haze in a Class I area,'' \49\ and this determination was not
changed in the 2017 RHR. Critically, the statute and regulation both
require that the cause-or-contribute assessment consider all emissions
of visibility impairing pollutants from a state, as opposed to
emissions of a particular pollutant or emissions from a certain set of
sources.
---------------------------------------------------------------------------
\49\ 64 FR 35714, 35721 (July 1, 1999).
---------------------------------------------------------------------------
Nevada has one mandatory Class I Federal area within its borders,
the Jarbidge Wilderness Area located within the Humboldt National
Forest in the northeastern portion of Nevada.
For the second implementation period, the Regional Haze Planning
Work Group of the WRAP performed technical analyses,\50\ including
source apportionment modeling \51\ and weighted emissions potential
analyses \52\ to help assess source and state-level contributions to
visibility impairment at Jarbidge Wilderness Area and at Class I areas
in adjacent states. NDEP determined that the following Class I areas in
neighboring states are affected the most by emissions originating in
Nevada: Grand Canyon, Arizona; Ike's Backbone (Pine Mountain and
Mazatzal), Arizona; Desolation Wilderness, California; Craters of the
Moon, ID; Hells Canyon, Oregon; and Zion Canyon, Utah. NDEP used the
source apportionment modeling results to analyze significant
contributors at Jarbidge Wilderness Area.\53\ The overall
SO2 emissions sources for the most impaired days are
primarily from the states of California, Idaho, Oregon and Washington.
For all these states, contributions to sulfate are primarily from non-
EGU and industrial sources. Remaining anthropogenic source sectors
outside of point and mobile sources is the next largest contributor
among these states. Nevada's EGU sector is also one of the most
significant contributors to ammonium sulfate extinction at Jarbidge
Wilderness Area. For nitrate, the dominant WRAP source area
contributions for the most impaired days are from California, Idaho,
Oregon, and Washington. Mobile source emissions are the dominant source
category for NOX emissions, followed by non-EGU and area
sources.
---------------------------------------------------------------------------
\50\ The WRAP's Emissions Inventory and Modeling Protocols
Subcommittee, along with its contractor, Ramboll Inc., performed
these modeling analyses for the WRAP states, including Nevada. NDEP
also provided updated WRAP and WESTAR links in a clarification
letter. See Letter dated September 8, 2025, from Andrew Tucker,
Chief, Bureau of Air Quality Planning, NDEP, to Rynda Kay, Manager,
Geographic Strategies & Modeling Section, U.S. Environmental
Protection Agency Region 9.
\51\ The CAMx photochemical model version 7.0 with the Particle
Source Apportionment Technology (PSAT) tool was applied at a
regional level to separate U.S. anthropogenic contributions from
those of fire, natural, and international anthropogenic
contributions for a current period (2014-2018) and a future year in
2028. See section 4.3 of the 2022 Nevada Regional Haze Plan.
\52\ The Weighted Emissions Potential (WEP) tool is an analysis
technique that identifies the predominant emission source regions
contributing haze-forming pollutants at each Class I area based on 5
years of historical meteorology during the most impaired days. See
chapter 1 and section 4.4 of the 2022 Nevada Regional Haze Plan.
\53\ 2022 Nevada Regional Haze Plan, sections 4.3.2 and 4.3.3.
---------------------------------------------------------------------------
NDEP also used the source apportionment modeling results to
determine which Class I areas in adjacent states might be affected by
emissions from Nevada sources. NDEP identified the rank and percentage
of the total modeled concentration due to SO2 and
NOX emissions from sources within Nevada to the IMPROVE
monitors representing all Class I areas in the five adjacent states,
and evaluated total contributions compared to total light extinction at
each Class I area.\54\ The highest contribution from Nevada
anthropogenic sources to an out-of-state Class I area's sulfate
extinction in 2028 is Craters of the Moon at 1.15 percent. Among all
evaluated Class I areas, EGU, non-EGU, and remaining anthropogenic
sources tend to be the largest contributors to sulfate extinction. The
highest contribution to an out-of-state Class I area's nitrate
extinction in 2028 is Desolation Wilderness at 6.16 percent.
Additionally, among all evaluated Class I areas, NDEP indicated that
the mobile source sector is generally the largest contributor to
nitrate extinction.
---------------------------------------------------------------------------
\54\ 2022 Nevada Regional Haze Plan, tables 4-4, 4-5, and 4-6.
---------------------------------------------------------------------------
In sum, NDEP determined that sources and emissions within the state
contribute to visibility impairment at both Jarbidge Wilderness Area
and at certain Class I areas in nearby states.\55\ Furthermore, the
state took part in the consultation process as a member of the Regional
Haze Planning Work Group (RHPWG) of the WRAP.\56\ As discussed in
further detail below, Nevada also identified sources using a Q/d > 5
[[Page 48487]]
analysis \57\ to conduct a four-factor analysis, and determined
reasonable measures that could be implemented by 2028, considering the
cost of compliance, the time necessary for compliance, the energy and
non-air quality environmental impacts, and the remaining useful life of
any potentially affected sources. We therefore propose to find that
Nevada appropriately identified Class I areas that may be affected be
emissions from the state.
---------------------------------------------------------------------------
\55\ Id.
\56\ 2022 Nevada Regional Haze Plan, appendix E.
\57\ Q/d represents a source's annual emissions in tons (Q)
divided by the distance in kilometers (d) between the source and the
nearest Class I area. For regional haze purposes, only primary
visibility-impairing pollutants were included in a source's total Q:
NOX, SO2, and PM10. Nevada used
emissions from the 2014v2 NEI to calculate a source's total Q.
---------------------------------------------------------------------------
D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
Section 51.308(f)(1) requires states to determine the following for
``each mandatory Class I Federal area located within the State'':
baseline visibility conditions for the most impaired and clearest days,
natural visibility conditions for the most impaired and clearest days,
progress to date for the most impaired and clearest days, the
differences between current visibility conditions and natural
visibility conditions, and the URP. This section also provides the
option for states to propose adjustments to the URP line for a Class I
area to account for visibility impacts from anthropogenic sources
outside the United States and/or the impacts from wildland prescribed
fires that were conducted for certain, specified objectives.\58\
---------------------------------------------------------------------------
\58\ 40 CFR 51.308(f)(1)(vi)(B).
---------------------------------------------------------------------------
In the 2022 Nevada Regional Haze Plan, NDEP noted that Jarbidge
Wilderness Area has 2000-2004 baseline visibility conditions of 2.56
deciviews on the 20 percent clearest days and 8.73 deciviews on the 20
percent most impaired days.\59\ NDEP calculated an estimated natural
visibility conditions of 1.14 deciviews on the 20 percent clearest days
and 5.23 deciviews on the 20 percent most impaired days for the
Jarbidge Wilderness Area.\60\ The current visibility conditions, which
are based on 2014-2018 monitoring data, were 1.84 deciviews on the
clearest days and 7.97 deciviews on the most impaired days,\61\ which
are 0.70 deciviews and 2.74 deciviews greater than natural conditions
on the respective sets of days.\62\ The progress to date, subtracting
current conditions from baseline conditions, yields a 0.72 deciview
improvement for the 20 percent clearest days and 0.76 deciview
improvement for the 20 percent most impaired days.\63\
---------------------------------------------------------------------------
\59\ 2022 Nevada Regional Haze Plan, section 2.2.
\60\ Id., tables 2-1 and 2-2. NDEP stated elsewhere in Chapter 2
that natural visibility on the 20 percent most impaired days for the
Jarbidge Wilderness Area is 7.39 deciviews. However, in Chapter 6,
NDEP clarified that this 7.39 deciviews is the value used for the
adjusted URP and includes international impacts and prescribed fire
impacts.
\61\ Id., section 2.4 and table 2-3.
\62\ Id. NDEP mistakenly calculated the difference for the most
impaired days relative to the adjusted URP, rather than natural
conditions, yielding a difference of 0.58 deciviews. The correct
difference of 2.74 deciviews can be derived by subtracting natural
conditions (5.23 deciviews) from current conditions (7.97
deciviews).
\63\ Id. table 2-3.
---------------------------------------------------------------------------
NDEP chose to adjust its URP for international anthropogenic
impacts and to account for the impacts of wildland prescribed fires
using adjustments developed by the WRAP.\64\ The WRAP/WAQS Regional
Haze modeling platform used scaled 2014 NEI wildland prescribed fire
data for purposes of calculating the URP adjustments. WRAP used the
results from the CAMx 2028OTBa2 High-Level Source Apportionment (H-L
SA) run to determine pollutant concentrations attributable to
international emissions and to prescribed fire. These concentrations
were then used in a relative sense: the modeled relative effect of
removing each of these emissions categories was applied to projections
of 2028 concentrations. This gave a reduced 2028 concentration, and the
reduction was taken as the contribution of prescribed fire and
international emissions for use in adjusting the URP. The international
and prescribed fire contributions were therefore calculated in a manner
consistent with each other and with the 2028 projections. This approach
is consistent with the default method described in the EPA's September
2019 regional haze modeling Technical Support Document (``EPA 2019
Modeling TSD'') \65\ and with the source apportionment approach
described in the EPA's 2018 Visibility Tracking Guidance.\66\ Two
different adjusted glidepath options, ``International Emissions Only
(A)'' and ``International Emissions + Wildland Rx Fire (B)'', were made
available on the WRAP Technical Support System (TSS) \67\ to adjust the
URP glidepath end points projections at 2064 for Class I Federal areas
on the most impaired days. NDEP used the ``International Emissions +
Wildland Rx Fire (B)'' option to adjust the URP for Jarbidge.\68\ The
inclusion of international emissions added 2.0 dv to the 2064 URP end
point, and the wildland prescribed fire added an another 0.2 dv,
resulting in a 7.4 dv adjusted URP value for 2064. Based on this
adjustment, NDEP calculated an annual URP of 0.022 deciviews per year
needed to reach natural visibility on the 20 percent most impaired
days.\69\
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\64\ Id. sections 2.6 and 6.9.1.
\65\ Memorandum from Richard A. Wayland, Director, Air Quality
Assessment Division, EPA, to Regional Air Division Directors,
Subject: ``Availability of Modeling Data and Associated Technical
Support Document for the EPA's Updated 2028 Visibility Air Quality
Modeling,'' September 19, 2019, available at https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional, direct link: https://www.epa.gov/visibility/technical-support-document-epas-updated-2028-regional-haze-modeling.
\66\ Memorandum from Richard A. Wayland, Director, Air Quality
Assessment Division, EPA, to Regional Air Division Directors,
Subject: ``Technical Guidance on Tracking Visibility Progress for
the Second Implementation Period of the Regional Haze Program,''
December 20, 2018, available at https://www.epa.gov/sites/default/files/2018-12/documents/technical_guidance_tracking_visibility_progress.pdf.
\67\ WRAP Technical Support System, http://views.cira.colostate.edu/tssv2/. The specific WRAP procedures for
adjusting the URP are described in ``Procedures for Making
Visibility Projections and Adjusting Glidepaths using the WRAP-WAQS
2014 Modeling Platform (October 21, 2021, updated final draft),''
available at https://views.cira.colostate.edu/iwdw/docs/WAQS_and_WRAP_Regional_Haze_spec_sheets.aspx, direct link: https://views.cira.colostate.edu/docs/IWDW/PlatformDocs/WRAP_2014/2028_Vis_Proj_Glidepath_Adj_20211021_draft_final.pdf.
\68\ 2022 Nevada Regional Haze Plan, section 6.9.1 and Figure 6-
2.
\69\ Id. section 2.6.
---------------------------------------------------------------------------
The EPA is proposing to find that the Nevada Regional Haze Plan
meets the requirements of 40 CFR 51.308(f)(1) related to the
calculations of baseline, current, and natural visibility conditions;
progress to date; the differences between current visibility conditions
and natural visibility conditions, and the URP for the second
implementation period.
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. 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 in a four-factor analysis for the
second implementation period and
[[Page 48488]]
how the four factors were taken into consideration in selecting the
emissions reduction measures for inclusion in the long-term
strategy.\70\
---------------------------------------------------------------------------
\70\ 40 CFR 51.308(f)(2)(iii).
---------------------------------------------------------------------------
States may rely on technical information developed by the RPOs of
which they are members to select sources for four-factor analysis and
to conduct that analysis, as well as to satisfy the documentation
requirements under 40 CFR 51.308(f). Where an RPO has performed source
selection and/or four-factor analyses (or considered the five
additional factors in 40 CFR 51.308(f)(2)(iv)) for its member states,
those states may rely on the RPO's analyses for the purpose of
satisfying the requirements of 40 CFR 51.308(f)(2)(i) so long as the
states have a reasonable basis to do so and all state participants in
the RPO process have approved the technical analyses.\71\ 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.
---------------------------------------------------------------------------
\71\ Id.
---------------------------------------------------------------------------
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 and coordinate emissions management strategies containing the
emissions reduction measures that are necessary to make reasonable
progress. Section 51.308(f)(2)(ii)(A) and (B) require states to
consider the emissions reduction measures identified by other states as
necessary for reasonable progress and to include agreed upon measures
in their SIPs, respectively. Section 51.308(f)(2)(ii)(C) speaks to what
happens if states cannot agree on what measures are necessary to make
reasonable progress.
The following sections summarize NDEP's long-term strategy for the
second planning period, as set forth in the 2022 Nevada Regional Haze
Plan. The EPA's evaluation with respect to the requirements of Sec.
51.308(f)(2) is provided in section IV.E.7.
1. Determination of Which Pollutants To Consider
In Chapter 3 of the 2022 Nevada Regional Haze Plan, NDEP provided
summaries of its base year (2014) and projected (2028) emissions
inventories for visibility impairing pollutants. In Chapter 4 of the
2022 Nevada Regional Haze Plan, NDEP provided the results of visibility
and source apportionment modeling performed by WRAP. Based on this
information and analyses, in Chapter 5 of the 2022 Nevada Regional Haze
Plan, NDEP chose to consider NOX, SO2, and
PM10 in its source selection and four factor analyses.
2. Source Selection
NDEP used a Q/d \72\ threshold of five based on the 2014 National
Emissions Inventory (NEI) Version 2 (2014v2) NOX,
SO2, and PM10 emissions, which resulted in a list
of eight sources, as shown in table 1.\73\ These eight sources are:
RGGS, North Valmy Generating Station, McCarran International Airport,
Lhoist North America Apex Plant, Nevada Cement Fernley Plant, Tracy
Generating Station, TS Power Plant, and Graymont Pilot Peak Plant.
---------------------------------------------------------------------------
\72\ Q/d represents a source's annual emissions in tons per year
(tpy) (Q) divided by the distance in kilometers (km) (d) between the
source and the nearest Class I area.
\73\ 2022 Nevada Regional Haze Plan, chapter 5.
Table 1--List of Selected Sources
----------------------------------------------------------------------------------------------------------------
Distance
Nearest Class I area CIA state Total Q to CIA Q/d
(CIA) (tpy) (km)
----------------------------------------------------------------------------------------------------------------
RGGS............................... Grand Canyon NP....... AZ 6,944 84 82.56
North Valmy Generating Station..... Jarbidge Wilderness NV 12,173 162 75.10
Area.
McCarran International Airport..... Grand Canyon NP....... AZ 2,770 107 25.97
Lhoist North America Apex Plant.... Grand Canyon NP....... AZ 1,662 88 18.84
Nevada Cement Fernley Plant........ Desolation Wilderness. CA 1,482 102 14.55
Tracy Generating Station........... Desolation Wilderness. CA 683 82 8.33
TS Power Plant..................... Jarbidge Wilderness NV 834 131 6.39
Area.
Graymont Pilot Peak Plant.......... Jarbidge Wilderness NV 673 131 5.13
Area.
----------------------------------------------------------------------------------------------------------------
Source: 2022 Nevada Regional Haze Plan, table 5-1.
NDEP screened out three of the eight sources listed above prior to
conducting four-factor analyses. As explained in in section IV.A. of
this document, NDEP screened out RGGS because it ceased operation and
was completely decommissioned and dismantled. NDEP also screened out
McCarran International Airport, now named the Harry Reid International
Airport, because the vast majority of emissions are due to aircraft
takeoffs, landings, and ground movement, falling outside of the local
air agencies' scope of authority. Additionally, the allowable emissions
for NOX, SO2, and PM10 listed in the
operating permit for the airport yielded a Q/d of 1.35, which was below
NDEP's Q/d threshold of five.\74\ NDEP also removed TS Power Plant as
the facility is operating BACT controls for NOX,
SO2, and PM10.\75\ The TS Power Plant has one
pulverized coal, dry bottom boiler with a gross capacity of 220
megawatts (MW). NDEP also provided a demonstration to show that the
BACT controls are not necessary to make reasonable progress, because
historical and projected emission rates for NOX,
SO2, and PM10 remain low and consistent, making
it reasonable to assume that the source will continue to implement its
existing measures and will not increase its emissions rates.\76\
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\74\ Id. table 5-2.
\75\ Table 5-39 of the 2022 Nevada Regional Haze Plan lists the
existing controls that reduce visibility impairing pollutants at the
facility, along with the corresponding BACT emission limits that can
be found in the facility's air quality operating permit (Permit No.
AP4911-2502).
\76\ 2022 Nevada Regional Haze Plan, section 5.4.6 and appendix
B.3.
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3. Overall Approach to Four-Factor Analyses
The remaining five sources that NDEP identified in the source
selection step to require a four-factor analysis elected to submit
their own four-factor analyses to evaluate existing controls and
consider potential additional control measures that may be necessary to
achieve reasonable progress. For the majority of
[[Page 48489]]
the sources, NDEP requested additional information to supplement the
initial four-factor analyses submitted by sources, resulting in
multiple response letters from the sources to bolster the documentation
for the four-factor analysis. Based on its review of these analyses and
applying a cost-effectiveness threshold of $10,000 per ton of pollutant
reduced, Nevada made a ``Reasonable Progress Control Determination''
for each relevant unit and pollutant.\77\ In addition, for each unit
and pollutant where it determined that no additional control measures
are necessary to make reasonable progress at a source, NDEP evaluated
whether existing control measures implemented at the source are
necessary to make reasonable progress.
---------------------------------------------------------------------------
\77\ Appendix B of the 2022 Nevada Regional Haze Plan contains
all documentation of Nevada's reasonable progress conclusions each
source, including the Reasonable Progress Control Determinations,
four-factor analyses, and any subsequent response letters.
---------------------------------------------------------------------------
4. Summary of Four-Factor Analyses
a. North Valmy Generating Station
The North Valmy Generating Station is an electric generating
facility owned by NV Energy (NVE) consisting of two coal-fired boilers
that provide high pressure steam to steam turbine generators used to
produce electricity.\78\ The facility screened in with a Q/d value of
75.14, and the nearest Class I area is Jarbidge Wilderness Area at 162
kilometers away.
---------------------------------------------------------------------------
\78\ 2022 Nevada Regional Haze Plan, section 5.5 and appendix
B.6.
---------------------------------------------------------------------------
In the 2022 Nevada Regional Haze Plan, NVE committed to shutting
down and permanently ceasing operation at both units at North Valmy by
December 31, 2028. The effective closure date was incorporated into the
consideration of the remaining useful life for each potential new
measure considered for the North Valmy units. NDEP had relied on a
closure date of December 31, 2028 for Units 1 and 2 as necessary to
achieve reasonable progress.
However, as explained in the 2025 SIP Supplement, changes in the
energy landscape along with transmission system reliability
considerations in Nevada necessitated reconsideration of the retirement
of North Valmy Units 1 and 2 by December 31, 2028. In August 2023, NVE
filed an application for the Fifth Amendment to the 2021 Joint
Integrated Resource Plan (IRP) with the Public Utilities Commission of
Nevada (PUCN), seeking approval to convert the existing coal fueled
plant at North Valmy Generating Station to a natural gas-fueled plant
and continue operating it to 2049. In March 2024, the PUCN approved
proceeding with these projects at North Valmy. NDEP withdrew the
reasonable progress determination for North Valmy Generating Station on
July 27, 2023, and then submitted a new reasonable progress
determination for North Valmy Generating Station as part of the 2025
SIP Supplement on May 28, 2025. The EPA is not proposing to act on the
revised reasonable progress determination for North Valmy Generating
Station in the 2025 SIP Supplement at this time.
b. Tracy Generating Station
Tracy Generating Station is an electric generating facility owned
by NVE that consists of one conventional, pipeline natural gas-fired
113 MW steam boiler (Unit 3); two pipeline natural gas and distillate-
fired combustion turbines at 83.5 MW each (Units 5 and 6); one pipeline
natural gas-fired combined cycle unit at 107 MW with 23 MW duct burners
(Unit 7, also known as Pi[ntilde]on Pine Unit 4), and two pipeline
natural gas-fired combined cycle units at 254 MW each (Units 32 and
33).\79\ The facility screened in with a Q/d value of 8.33, and the
nearest Class I area is Desolation Wilderness, California at 81
kilometers away. NDEP screened out Units 5 and 6 from further
consideration of potential new control measures based on low
utilization and low emissions.\80\ In addition, NDEP screened out Units
32 and 33 based on existing effective controls (Dry Low NOX
combustor and SCR) and low emissions.\81\
---------------------------------------------------------------------------
\79\ 2022 Nevada Regional Haze Plan, section 5.6 and appendix
B.5.
\80\ See 2022 Nevada Regional Haze Plan, table 5-13 for the
baseline emissions for Tracy Units 5, 6, 32, and 33. Average
NOX emissions for Units 5, 6, 32, and 33 are 12, 10.6,
38.5, and 37.5 tpy, respectively. Average SO2 emissions
for Units 5, 6, 32, and 33 are 0.3, 0.2, 4, and 4 tpy, respectively.
Average PM10 emissions for Units 5, 6, 32, and 33 are 1,
0.8, 24.3, 23.8 tpy, respectively.
\81\ Id.
---------------------------------------------------------------------------
NDEP evaluated Tracy Unit 3 for potential new control measures for
NOX emissions considering the four statutory factors. NDEP
did not evaluate new control measures for SO2 and
PM10 at the Tracy Generating Station, as all units burn
natural gas, resulting in low annual emissions for SO2 and
PM10. Additionally, to comply with BART during the first
round of Regional Haze in Nevada, Unit 3 discontinued the occasional
use of distillate fuel and was retrofitted with the best available Low-
NOX Burners. These control measures are already incorporated
into Nevada's SIP. A summary of the cost-effectiveness values for each
technically feasible control technology considered at Tracy Unit 3 is
provided in table 2.
Table 2--Tracy Four-Factor Analysis Cost-Effectiveness Summary
----------------------------------------------------------------------------------------------------------------
Total Cost-
Control Unit Baseline Tons reduced annualized effectiveness
emissions (tpy) costs (ton)
----------------------------------------------------------------------------------------------------------------
SNCR......................... Tracy Unit 3... 138 tpy NOX.... 35 tpy NOX..... $474,641 $13,561
SCR.......................... Tracy Unit 3... 138 tpy NOX.... 124 tpy NOX.... 1,387,040 11,186
----------------------------------------------------------------------------------------------------------------
Source: 2022 Nevada Regional Haze Plan, table 5-16.
For Unit 3, NDEP identified SCR and SNCR as technically feasible
NOX control measures. The four-factor analysis for Unit 3
used baseline emissions derived from the annual average of emissions
observed from 2016 through 2020. NDEP estimated two to three years to
fully implement SCR or SNCR at Unit 3. NDEP also factored in an annual
electricity cost for SCR to account for increased electrical demand
caused by a backpressure. NDEP relied on the remaining useful life of
20 years and 30 years, respectively, for SNCR and SCR. As shown in
table 4, all potential control measures evaluated for Unit 3 yield a
cost-effectiveness value above NDEP's threshold of $10,000 per ton of
NOX reduced.\82\ Based on the four statutory factors, NDEP
concluded that no new control measures for Tracy Unit 3 are necessary
to make reasonable progress.
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\82\ 2022 Nevada Regional Haze Plan, table 5-16.
---------------------------------------------------------------------------
For Unit 4 Pi[ntilde]on Pine, in the 2022 Nevada Regional Haze Plan
NDEP relied on a closure date of December 31, 2031, as necessary to
achieve reasonable progress. However, as explained in the 2025 SIP
Supplement, changes in the energy landscape along with
[[Page 48490]]
transmission system reliability considerations in Nevada necessitated
reconsideration of the retirement of Tracy Unit 4 Pi[ntilde]on Pine by
December 31, 2031. Similar to what was done for North Valmy Generating
Station, NDEP withdrew the reasonable progress determination for Tracy
Unit 4 Pi[ntilde]on Pine on July 27, 2023, and then submitted a new
reasonable progress determination for this unit as part of the 2025 SIP
Supplement. The EPA is not proposing to act on the revised reasonable
progress determination for Tracy Unit 7 (Unit 4 Pi[ntilde]on Pine) in
the 2025 SIP Supplement at this time.
Further, NDEP also determined that the existing NOX
controls at Units 3, 5, 6, 7, 32, and 33 are necessary to make
reasonable progress. The existing requirements for Unit 3 are already
incorporated into the Nevada SIP as BART requirements. For the
remaining existing controls, NDEP therefore submitted portions of Tracy
Generating Station's permit, Permit No. AP4911-0194.04 for
incorporation into the SIP.\83\ Table 3 summarizes the relevant permit
conditions and controls, emissions limits, and associated requirements
at Tracy Generating Station, which NDEP submitted for SIP approval. To
make the new control measures enforceable, NDEP adopted and submitted
emissions limitation and associated requirements as part of regulation
R138-24.
---------------------------------------------------------------------------
\83\ See 2022 Nevada Regional Haze Plan, section 5.6.7 and
appendix A.5. See also 2025 Supplement, appendix A.2.
Table 3--Tracy Permit Conditions Incorporated by Reference
------------------------------------------------------------------------
Tracy Generating Station, Permit No. AP4911-0194.04
-------------------------------------------------------------------------
Citation Permit condition
------------------------------------------------------------------------
Unit 5 (System 05A--Clark Mountain Combustion Turbine #3)
------------------------------------------------------------------------
NOX:
IV.B.1.a.......................... Emissions from S2.006 shall be
controlled by Dry LNB while
combusting natural gas only.
Emissions from S2.006 shall be
controlled with Water Injection
while combusting No. 2
Distillate Fuel Oil under
``Emergency'' conditions
defined in B.2.c. of this
section.
IV.B.3.f.......................... The discharge of NOX (oxides of
nitrogen) to the atmosphere
shall not exceed:
(1) 9 parts per million by
volume (ppmv) at 15 percent
oxygen and on a dry basis,
based on a 24-hour rolling
period.
(2) 42.0 pounds per hour,
based on a 720-hour rolling
period.
(3) 122.64 tons per year,
based on a 12-month rolling
period.
------------------------------------------------------------------------
Unit 6 (System 06A--Clark Mountain Combustion Turbine #4)
------------------------------------------------------------------------
NOX:
IV.D.1.a.......................... Emissions from S2.007 shall be
controlled by Dry LNB while
combusting Pipeline Natural Gas
only. Emissions from S2.006
shall be controlled with Water
Injection while combusting No.
2 Distillate Fuel Oil under
``Emergency'' conditions
defined in D.2.c. of this
section.
IV.D.3.f.......................... The discharge of NOX (oxides of
nitrogen) to the atmosphere
shall not exceed:
(1) 9 parts per million by
volume (ppmv) at 15 percent
oxygen and on a dry basis,
based on a 24-hour rolling
period.
(2) 42.0 pounds per hour,
based on a 720-hour rolling
period.
(3) 122.64 tons per year,
based on a 12-month rolling
period.
------------------------------------------------------------------------
Unit 7 (System 07C--Tracy Unit #4 Pi[ntilde]on Pine Combustion Turbine)
------------------------------------------------------------------------
NOX:
IV.F.1............................ a. Emissions from S2.009 shall
be controlled by a Steam
Injection for control of NOX.
b. Emissions from S2.009.1 shall
be controlled by Dry Low NOX
Burners.
------------------------------------------------------------------------
Unit 32 (System 32--Combined Cycle Combustion Turbine Circuit No. 8)
------------------------------------------------------------------------
NOX:
IV.L.1.a.......................... NOX emissions from S2.064 and
S2.065 shall be controlled by
SCR. The SCR shall utilize
Ammonia Injection into the SCR
at a volume specified by the
manufacturer.
IV.L.3.g.......................... The discharge of NOX to the
atmosphere shall not exceed 2.0
parts per million by volume
(ppmv) at 15 percent oxygen on
a dry basis, based on a 3-hour
rolling period.
------------------------------------------------------------------------
Unit 33 (System 33--Combined Cycle Combustion Turbine Circuit No. 9)
------------------------------------------------------------------------
NOX:
IV.M.1.a.......................... NOX emissions from S2.066 and
S2.067 shall be controlled by
SCR. The SCR shall utilize
Ammonia Injection into the SCR
at a volume specified by the
manufacturer.
IV.M.3.g.......................... The discharge of NOX to the
atmosphere shall not exceed
2.00 parts per million (ppmv)
by volume at 15 percent oxygen
and on a dry basis, per 3-hour
rolling period.
------------------------------------------------------------------------
All Units--Monitoring, Recordkeeping, Reporting
------------------------------------------------------------------------
V.A & V.C............................. NOX Continuous Emissions
Monitoring System (CEMS)
Conditions.
------------------------------------------------------------------------
Source: 2022 Nevada Regional Haze Plan, table 5-17.
[[Page 48491]]
c. Lhoist North America Apex Plant
Lhoist North America Apex Plant is a lime production facility
located in Clark County northeast of the Las Vegas metropolitan area.
The plant includes four horizontal rotary preheater lime kilns, which
are permitted to utilize coal, petroleum coke, and/or natural gas.\84\
The permitting authority for this facility is the Clark County
Department of Environment and Sustainability (DES). NDEP derived the
baseline emissions for the facility from the annual average of
emissions reported from 2016 to 2018. The facility screened in with a
Q/d value of 18.84, and the nearest Class I area is Grand Canyon
National Park at 88 kilometers away. A summary of NDEP's cost-
effectiveness analysis for the Apex Plant is provided in table 4.
---------------------------------------------------------------------------
\84\ 2022 Nevada Regional Haze Plan, section 5.7 and appendix
B.1.
---------------------------------------------------------------------------
For NOX, NDEP identified LNB and SNCR as technically
feasible control measures. Kilns 3 and 4 already implement LNB, so NDEP
only evaluated LNB for Kilns 1 and 2. None of the kilns currently
operate SNCR, so NDEP evaluated SNCR for all four kilns. For purposes
of its analysis, NDEP assumed LNB would achieve a 10 percent
NOX reduction, while SNCR would achieve a 20 percent
NOX reduction at Kilns 1, 2, and 3, and a 50 percent
NOX reduction at Kiln 4.\85\ NDEP also assumed 20 years for
the remaining useful life of the units.
---------------------------------------------------------------------------
\85\ The control efficiency of SNCR differs between Kiln 4 and
the rest of the Apex Plant kilns due to differences in age and
configuration (discussed further in Lhoist's four-factor analysis).
See 2022 Nevada Regional Haze Plan, Chapter 5.7.3.
---------------------------------------------------------------------------
For SO2, at Kilns 2 and 4, NDEP identified a switch to
use of natural gas only as a technically feasible control measure. NDEP
found that a fuel switch to use of natural gas was not feasible for
Kilns 1 and 3 because these kilns are intended to produce dolomitic
lime, which cannot be produced using 100 percent natural gas. NDEP also
noted that, while switching to 100 percent natural gas at Kilns 2 and 4
would reduce SO2 and PM10 emissions, it would
increase NOX emissions. Therefore, for its analysis of a
fuel switch, NDEP calculated baseline emissions and tons reduced from
the sum of NOX, SO2, and PM10
emissions. NDEP also assumed an estimated control life of 20 years.
NDEP found that existing baghouses that meet the definition of best
available control technology (BACT) at all four kilns constitute
effective controls for PM10.
Table 4--Apex Plant Four-Factor Analysis Cost-Effectiveness Summary
----------------------------------------------------------------------------------------------------------------
Control Total Cost-
Control Kiln Baseline efficiency Tons reduced annualized effectiveness
emissions (tpy) (%) (tpy) costs (ton)
----------------------------------------------------------------------------------------------------------------
LNB.......................... 1 304 tpy NOX..... 10 30.35 tpy NOX.. $25,792 $850
2 19 tpy NOX...... 10 1.91 tpy NOX... 25,792 13,494
SNCR......................... 1 304 tpy NOX..... 20 60.70 tpy NOX.. 164,394 2,708
2 19 tpy NOX...... 20 3.82 tpy NOX... 144,681 37,847
3 154 tpy NOX..... 20 30.84 tpy NOX.. 154,044 4,995
4 687 tpy NOX..... 50 343.34 tpy NOX. 262,344 764
Fuel Switch to 100% NG....... 2 23.66 tpy NOX, \a\ 99.92 1.02 tpy NOX, 8,708,565 8,666,204
SO2, and PM10. SO2, and PM10
\b\.
4 724.46 tpy NOX, \a\ 99.62 -147.92 tpy 1,589,821 N/A
SO2, and PM10. NOX, SO2, and
PM10 \b\.
----------------------------------------------------------------------------------------------------------------
Source: 2022 Nevada Regional Haze Plan, table 5-22.
\a\ The control efficiency is for SO2 emissions only.
\b\ The tons reduced for fuel switch represent the net emissions change including NOX, SO2, and PM10. For Kiln
4, the increase in NOX emissions surpasses the reduced SO2 and PM10 emissions, resulting in an overall
increase in emissions (negative tons reduced value).
Table 4 summarizes the cost-effectiveness analysis for the Apex
Plant. Based on the four statutory factors, NDEP concluded that the
implementation of LNB at Kiln 1, and the implementation of SNCR at
Kilns 1, 3, and 4 are necessary to achieve reasonable progress during
the second implementation period, as the cost-effectiveness values for
these controls were below NDEP's threshold. LNB were recently installed
on Kilns 3 and 4 and NDEP determined that the continued use of LNB on
Kiln 3 and 4 is necessary to make reasonable progress as well.
Accordingly, Clark County DES incorporated these new limits and other
associated requirements into the Apex Plant's air quality operating
permit,\86\ and NDEP submitted the relevant portions of the Apex
Plant's permit, Authority to Construct (ATC) Permit, for a Major Part
70 Source, Source ID: 3, for SIP approval.\87\ Table 5 summarizes the
relevant permit conditions for controls, emissions limits, and
associated requirements at the Apex Plant for approval into the SIP.
NDEP clarified in the 2025 SIP Supplement that Apex's ATC Permit
expired 18 months after its original issue date of August 3, 2022, and
was reissued by the Clark County DES on February 6, 2024. This permit
was again renewed on April 30, 2025, and NDEP submitted the latest
version of the permit in appendix A.1 of the 2025 SIP Supplement.
---------------------------------------------------------------------------
\86\ New NOX emission limits (and other requirements)
that reflect the use LNB and SNCR at Kilns 1, 3, and 4, are found in
appendix B.1.a of the 2022 Nevada Regional Haze Plan.
\87\ 2022 Nevada Regional Haze Plan appendix A.1. The Apex Plant
is located in Clark County, so the permit for the facility is issued
and enforced by the Clark County DES.
[[Page 48492]]
Table 5--Apex Plant ATC Permit Conditions Incorporated by Reference
------------------------------------------------------------------------
Apex Plant, Authority to Construct Permit for a Major Part 70 Source,
Source ID: 3, Clark County DES
-------------------------------------------------------------------------
Citation Permit condition
------------------------------------------------------------------------
Control Requirements (Facility-Wide)
------------------------------------------------------------------------
NOX:
2.2.1............................. The control requirements and the
NOX emission reductions
proposed in the ATC are
permanent and shall not be
removed, changed, revised, or
modified without the approval
of NDEP and the EPA upon
becoming effective.
2.2.2............................. Effective no later than two
years after the EPA's approval
of the controls determination
associated with the SIP, the
permittee shall install and
maintain low-NOX burners (LNB)
on Kilns 1, 3 and 4 in order to
achieve a reduction of NOX
emissions (emission units
(EUs): K102, K302, and K402).
2.2.3............................. Effective no later than two
years after the EPA's approval
of the controls determination
associated with the SIP, the
permittee shall install,
operate, and maintain selective
non-catalytic reduction (SNCR)
on Kilns 1, 3, and 4 (EUs:
K102, K302, and K402) to
achieve reduction of NOX
emissions.
------------------------------------------------------------------------
Emission Limits (Facility-Wide)
------------------------------------------------------------------------
NOX:
3.2.1............................. Effective no later than two
years after the EPA's approval
of the control's determination
associated with the SIP, the
permittee shall limit total NOX
emissions from all operating
kilns to 3.75 tons per day
based on a consecutive 30-day
average (EUs: K102, K202, K302,
and K402).
3.2.2............................. Effective no later than two
years after the EPA's approval
of the control's determination
associated with the SIP, the
permittee shall limit the
combined total NOX emissions
from all operating kilns to
3.59 lb/tons of lime produced
(tlp) based on a consecutive 12-
month average (EUs: K102,
K202, K302, and K402).
------------------------------------------------------------------------
Monitoring, Recordkeeping, and Reporting Requirements
------------------------------------------------------------------------
NOX:
4.1............................... Monitoring.
4.3............................... Recordkeeping.
4.4.7, 4.4.8, 4.4.15, 4.4.16...... Reporting and Notifications.
------------------------------------------------------------------------
Source: 2022 Nevada Regional Haze Plan, table 5-23 and 2025 SIP
Supplement, appendix A.1.
d. Graymont Pilot Peak Plant
Graymont Pilot Peak Plant is a lime plant owned by Graymont Western
US, Inc. that consists of three horizontal rotary preheater lime
kilns.\88\ The three kilns use coal as a primary fuel source. Kilns 1,
2, and 3 are permitted for producing lime at a rate of 25, 33.3, and 50
tons per hour, respectively. The facility initially screened in with a
Q/d value of 5.15, and the nearest Class I area is the Jarbidge
Wilderness Area at 130 kilometers away. The emissions used were from
the 2014 NEIv2. However, updated NOX emissions later
resulted in a Q/d value of 4.61.\89\ Emissions for 2015-2018 also
yielded Q/d values below 5. Emissions reported in 2019 and 2020 yielded
Q/d values above 5, but NDEP cited several reasons for still screening
out the facility, including the fact that using 2017 NEI data yields a
Q/d of 3.66, and the overall average Q/d for the most recent seven
years was below the threshold of 5. For these reasons, NDEP formally
screened the facility out of a four-factor analysis requirement, but
included information submitted for the facility's four-factor analysis
in the Plan.
---------------------------------------------------------------------------
\88\ 2022 Nevada Regional Haze Plan, section 5.8 and appendix
B.2.
\89\ 2022 Nevada Regional Haze Plan tables 5-27, 5-28, and 5-29.
Graymont indicated that the emissions reported in the 2014 NEIv2,
particularly the NOX emissions, did not agree with what
was submitted by Graymont for Pilot Peak's 2014 Annual Emission
Inventory (AEI). Graymont's AEI for Pilot Peak in 2014 resulted in a
Total Q of 604 tons per year (tpy), rather than 673, resulting in a
Q/d of 4.61. The AEI is calculated using the reporting requirements
in the facility's air quality operating permit.
---------------------------------------------------------------------------
In addition, NDEP evaluated whether any existing measures at the
facility were necessary to achieve reasonable progress. NDEP provided a
weight-of-evidence demonstration for existing SO2 and
PM10 control measures at the Pilot Peak Plant to determine
that these controls are not necessary to make reasonable progress. NDEP
indicated that historical and projected emissions rates for
SO2 and PM10 remain low and consistent, making it
reasonable to assume that the source will continue to implement its
existing measures and will not increase its emissions rate. For the
control of NOX emissions, Graymont Western has implemented
LNB at all three of the Pilot Peak kilns in recent years. NDEP
identified the continued use of existing LNB at all three kilns as
necessary to make reasonable progress. Therefore, NDEP incorporated
these new limits, and associated requirements into Pilot Peak's air
quality operating permit and submitted the relevant portions of the
permit as part of the 2022 Nevada Regional Haze Plan. NDEP issued a
minor revision to this permit on June 14, 2024, and submitted the
updated permit as part of the 2025 SIP Supplement.\90\ Table 6
summarizes the relevant permit conditions for controls, emissions
limits, and associated requirements at Pilot Peak, which NDEP submitted
for approval into the SIP in the 2025 SIP Supplement.
---------------------------------------------------------------------------
\90\ 2025 SIP Supplement, appendix A.3.
[[Page 48493]]
Table 6--Pilot Peak Plant Permit Conditions To Be Incorporated by
Reference
------------------------------------------------------------------------
Pilot Peak Plant, Permit No. AP3274-1329.03
-------------------------------------------------------------------------
Citation Permit condition
------------------------------------------------------------------------
Kiln 1 (System 10--Kiln #1 Circuit)
------------------------------------------------------------------------
NOX:
IV.K.1.a.......................... Emissions from S2.031 through
S2.033 shall be controlled by a
baghouse (D-85) and LNB.
IV.K.3.b.......................... The Permittee, within 240 days
upon issuance of this operating
permit, shall not discharge
into the atmosphere from the
exhaust stack of baghouse (D-
85) the following pollutants in
excess of the following
specified limits:
(1) Nevada Regional Haze SIP
Limit--The discharge of NOX to
the atmosphere shall not exceed
101.4 pounds per hour, based on
a 30-day rolling average
period.
IV.K.4.q, IV.K.4.u................ Specific Monitoring,
Recordkeeping, and Reporting
Requirements.
V.B-C............................. NOX CEMS Requirements for System
10 (S2.031, S2.032, and
S2.033), System 13 (S2.036,
S2.037, S2.038), and System 17
(S2.042, S2.043, S2.044).
------------------------------------------------------------------------
Kiln 2 (System 13--Kiln #2 Circuit)
------------------------------------------------------------------------
NOX:
IV.N.1.a.......................... Emissions from S2.036 through
S2.038 shall be controlled by a
baghouse (D-285) and LNB.
IV.N.3.b.......................... The Permittee, within 240 days
upon issuance of this operating
permit, shall not discharge
into the atmosphere from the
exhaust stack of baghouse (D-
285) the following pollutants
in excess of the following
specified limits:
(1) Nevada Regional Haze SIP
Limit--The discharge of NOX to
the atmosphere shall not exceed
107.4 pounds per hour, based on
a 30-day rolling average
period.
IV.N.4.q, IV.N.4.u................ Specific Monitoring,
Recordkeeping, and Reporting
Requirements.
V.B-C............................. NOX CEMS Requirements for System
10 (S2.031, S2.032, and
S2.033), System 13 (S2.036,
S2.037, S2.038), and System 17
(S2.042, S2.043, S2.044).
------------------------------------------------------------------------
Kiln 3 (System 17--Kiln #3 Circuit)
------------------------------------------------------------------------
NOX:
IV.S.1.a.......................... Emissions from S2.042 through
S2.044 shall be controlled by a
baghouse (D-385) and Low-NOX
Burners.
IV.S.3.b.......................... The Permittee, within 240 days
upon issuance of this operating
permit, shall not discharge
into the atmosphere from the
exhaust stack of baghouse (D-
385) the following pollutants
in excess of the following
specified limits:
(1) Nevada Regional Haze SIP
Limit--The discharge of NOX to
the atmosphere.
IV.S.4.q, IV.S.4.u................ Specific Monitoring,
Recordkeeping, and Reporting
Requirements.
V.B-C............................. NOX CEMS Requirements for System
10 (S2.031, S2.032, and
S2.033), System 13 (S2.036,
S2.037, S2.038), and System 17
(S2.042, S2.043, S2.044).
------------------------------------------------------------------------
Source: 2025 SIP Supplement, appendix A.3.
e. Nevada Cement Company (NCC) Fernley Plant
NCC Fernley Plant is a Portland cement manufacturing plant located
in Fernley, Nevada, consisting of two coal-fired long-dry process
kilns.\91\ The facility initially screened in with a Q/d value of
14.5,\92\ and the nearest Class I area is Desolation Wilderness at 102
kilometers away.
---------------------------------------------------------------------------
\91\ 2022 Nevada Regional Haze Plan, section 5.9 and appendix
B.4.
\92\ Additional CEMS data yielded a Q/d value of 30.9 due to
updated emissions of annual NOX and SO2. The
new value does not change the source selection outcome for this
facility.
---------------------------------------------------------------------------
The Fernley Plant is currently subject to an EPA Consent Decree to
control NOX and SO2 emissions.\93\ The Consent
Decree requires that both kilns at the Fernley Plant emit no more than
1.1 pound of SO2 per ton of clinker. To control
NOX emissions, the facility is required to install SNCR.
After the demonstration period, the consent decree requires the source
to submit a demonstration report for each kiln's SNCR performance, and
a final 30-day rolling average emission limit for NOX for
both kilns is then derived from the findings of the demonstration
report. The consent decree also requires the installation and continued
use of Continuous Emission Monitoring Systems (CEMS) for both kilns to
measure and monitor SO2 and NOX emissions. The
facility has since implemented CEMS for both kilns and relies on CEMS
for SO2 and NOX emissions reporting. NDEP stated
that it is relying on the consent decree to screen the facility out of
further consideration of potential new control measures, as the Consent
Decree requires BACT-level controls for NOX, SO2,
and PM10 emissions. Once the EPA has approved all necessary
limits through the process set forth in the CD, the CD requires these
new limits to be incorporated into a federally enforceable permit
issued under the Nevada SIP and then the facility's Title V permit. On
this basis, NDEP concluded that the consent decree controls for
NOX and SO2 are not necessary to achieve
reasonable progress.
---------------------------------------------------------------------------
\93\ United States of America v. Nevada Cement Company, Civil
Action No. 3:17-cv-00302-MMD-WGC. Available at https://www.justice.gov/enrd/consent-decree/file/1089586/download and
https://www.justice.gov/enrd/consent-decree/file/1089596/download.
---------------------------------------------------------------------------
Although the Fernley Plant was not required to conduct a four-
factor analysis for potential new control measures, NDEP asked the
facility to evaluate the continuous use of the facility's existing DSI
system, as opposed to occasional use, considering the four statutory
factors to achieve additional SO2 emissions reductions. The
analysis did not yield additional cost-effective controls. Considering
the four statutory factors outlined above, Nevada determined that the
upgrade of the existing DSI system to operate at full capacity for both
kilns is not necessary to achieve reasonable progress.
Further, based on consistent historical emissions and
PM10 emissions limits listed in the Fernley Plant's permit,
Permit No. AP3241-0387.02, NDEP also determined that the existing
baghouses used to achieve current PM10 emissions limits
listed in the facility's air quality
[[Page 48494]]
operating permit are not necessary to achieve reasonable progress.\94\
---------------------------------------------------------------------------
\94\ 2022 Nevada Regional Haze Plan, table 5-36. Additionally, a
demonstration with supporting documentation is included in the
source's Control Determination in appendix B.
---------------------------------------------------------------------------
5. Summary of Control Determinations
In summary, in the 2022 Nevada Regional Haze Plan concluded that
implementation of add-on controls at a lime production plant and the
continued use of several existing controls are all necessary to achieve
reasonable progress for the second planning period. NDEP submitted
permits incorporating these measures and associated monitoring,
recordkeeping, and reporting requirements in Appendix A of the 2025 SIP
Supplement. NDEP's control measure determinations from the 2022 Nevada
Regional Haze Plan, including specific permit conditions, are
summarized in table 7 of this document. As previously noted, the EPA is
not proposing to act on the revised reasonable progress determinations
for Tracy Unit 7 (Pi[ntilde]on Pine Unit 4) and North Valmy Generating
Station's Unit 1 and Unit 2, which were included in the 2025 SIP
Supplement, at this time.
Table 7--Nevada Regional Haze Control Measure Determinations
----------------------------------------------------------------------------------------------------------------
Existing or Compliance
Facility Unit Control Pollutant new measure deadline
----------------------------------------------------------------------------------------------------------------
Tracy......................... Unit 5.......... Dry Low NOX NOX Existing...... Upon SIP
Combustor. approval.
Unit 6.......... Dry Low NOX NOX Existing...... Upon SIP
Combustor. approval.
Unit 7 Steam injection. NOX Existing...... Upon SIP
(Pi[ntilde]on approval.
Pine Unit 4.
Unit 32......... Dry Low NOX NOX Existing...... Upon SIP
Combustor and approval.
SCR.
Unit 33......... Dry Low NOX NOX Existing...... Upon SIP
Combustor and approval.
SCR.
Lhoist North America Apex Kiln 1.......... LNB............. NOX New........... No later than
Plant. SNCR............ NOX New........... two years after
SIP approval.
Kiln 3.......... LNB............. NOX Existing......
SNCR............ NOX New...........
Kiln 4.......... LNB............. NOX Existing......
SNCR............ NOX New...........
Graymont Pilot Peak Plant..... Kiln 1.......... LNB............. NOX Existing...... Within 240 days
of operating
permit
issuance.
Kiln 2.......... LNB............. NOX Existing...... Within 240 days
of operating
permit
issuance.
Kiln 3.......... LNB............. NOX Existing...... Within 240 days
of operating
permit
issuance.
----------------------------------------------------------------------------------------------------------------
Source: 2022 Nevada Regional Haze Plan, table 5-5.
6. Additional Long-Term Strategy Requirements
NDEP indicated in its submittal that the State consulted with other
WRAP states in development of this SIP.\95\ Alaska, Arizona,
California, Colorado, Idaho, Montana, Nevada, New Mexico, North Dakota,
Oregon, South Dakota, Utah, Washington and Wyoming agreed to work
together to address regional haze in the western continental United
States. The majority of state consultation in the development of the
regional haze SIPs was conducted through the RHPWG. NDEP participated
in the RHPWG, which took the products of the WRAP technical analysis
and consultation process discussed above and developed a process for
establishing RPGs in the western Class I areas.
---------------------------------------------------------------------------
\95\ 2022 Nevada Regional Haze Plan, section 9.1.3.
---------------------------------------------------------------------------
The WEP analysis conducted by the WRAP results shows the
anthropogenic contributions at Jarbidge Wilderness Area. The point
source contributions for nitrate come from industrialized portions of
northern Nevada and along the Snake River Plain of Idaho, as well as
more distant areas in southern Nevada and portions of California,
including the Bay Area, Central Valley and Los Angeles area.\96\ The
WEP analysis also show contributions from the main transportation
corridors and population centers along I-80 in Nevada and Utah, I-84 in
Utah, Idaho, and Oregon, and I-5 in California to NOX
emissions at Jarbidge Wilderness Area. For sulfate, the point sources
contributions come from the industrialized portions of northeastern
Nevada and along the Snake River Plain of Idaho, as well as more
distant areas in the Bay Area of California and Northwest Oregon.\97\
For primary organic aerosol and elemental carbon, Nevada has one point
source contributing one to three percent of the respective component
impacting extinction at Jarbidge Wilderness Area.\98\
---------------------------------------------------------------------------
\96\ 2022 Nevada Regional Haze Plan, section 4.4.1.
\97\ Id. section 4.4.2.
\98\ Id. sections 4.4.3 and 4.4.4.
---------------------------------------------------------------------------
Aside from WRAP participation, NDEP engaged in direct state-to-
state consultations with neighboring states and other states that are
anticipated to impact visibility at Jarbidge, including: Arizona,
California, Idaho, Oregon, Utah, Washington, and Wyoming.\99\ NDEP
addressed the state consultation requirements of the rule and concluded
that there are no disagreements between Nevada and any neighboring
state. NDEP stated that it is not relying on reductions in another
state to achieve reasonable progress at an in-state Class I area, and
no neighboring states are relying on emissions reductions in Nevada to
achieve reasonable progress in out-of-state Class I areas.
---------------------------------------------------------------------------
\99\ Confirmation of state-to-state consultations is provided in
appendix E of the 2022 Nevada Regional Haze Plan.
---------------------------------------------------------------------------
In its submittal, NDEP also committed to continue consultation with
Arizona, California, Idaho, Oregon and Utah, and any other state which
may reasonably be anticipated to cause or contribute to visibility
impairment at the Jarbidge Wilderness Area.\100\ NDEP will also
continue consultation with any state for which Nevada's emissions may
reasonably be anticipated to cause or contribute to visibility
impairment in those states' Class I areas. NDEP also indicated that
there were no disagreements between NDEP and any neighboring state with
respect to regional haze commitments.
---------------------------------------------------------------------------
\100\ 2022 Nevada Regional Haze Plan, section 9.2.3.
---------------------------------------------------------------------------
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 emissions reductions
measures that are necessary
[[Page 48495]]
to make reasonable progress through an RPO, as long as the process has
been ``approved by all State participants.'' As explained above, NDEP
chose to rely on WRAP's technical information, modeling, and analysis
to support development of its long-term strategy. The WRAP technical
analyses on which NDEP relied are listed in the 2022 Nevada Regional
Haze Plan and include source contribution assessments and visibility
modeling information. NDEP further evaluated emissions reductions based
upon the new control measures that the State evaluated as necessary for
reasonable progress.
Section 51.308(f)(2)(iii) also requires that the emissions
information considered to determine the measures that are necessary to
make reasonable progress include information on emissions for the most
recent year for which the state has submitted triennial emissions data
to the EPA (or a more recent year), with a 12-month exemption period
for newly submitted data. The 2022 Nevada Regional Haze Plan included
2014 NEI emission data \101\ for NOX, SO2, PM,
VOCs and NH3 and 2017 Air Markets Program Data (AMPD)
emissions for NOX and SO2. NDEP also included
2017 NEI emissions data for comparison in its SIP submittal provided to
confirm there are no significant differences between the emissions
inventories developed and the most recent NEI to satisfy 40 CFR 51.308
(f)(2)(iii). NDEP's supplemental information included 2019 AMPD and
2017 NEI emission data for NOX (``2023 Nevada Regional Haze
Technical Supplement'').\102\ NDEP also included an evaluation of NEI
emissions from 2002 through 2017.
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\101\ WRAP agreed to rely on the 2014 NEIv2 for source
selection. This was done so that the Representative Baseline
emission inventory (based on years 2014-2018) used in the SIP would
agree with emissions used for source selection. At the time source
selection was conducted, in August of 2019, the 2017 and 2020 NEI
were not yet available. 2022 Nevada Regional Haze Plan, section 3.1.
\102\ Email dated July 31, 2023, from Steven McNeece, Nevada
Division of Environmental Protection, to Khoi Nguyen, EPA Region IX.
See also docket document ``Progress Report Period (2013-2019)
Emissions Analysis Supplement to the Nevada Regional Haze State
Implementation plan for the Second Planning Period''.
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Pursuant to Sec. 51.308(f)(2)(iv)(A), NDEP noted in section 7.5 of
its SIP submittal that existing and ongoing state and federal emissions
control programs that contribute to emissions reductions through 2028
would impact emissions of visibility impairing pollutants from point
and nonpoint sources in the second implementation period. NDEP included
in its SIP comprehensive lists of control measures, pollutants
addressed, and corresponding state regulations from the Nevada
Administrative Code (NAC).\103\
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\103\ 2022 Nevada Regional Haze Plan, section 7.5.1.
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NDEP's consideration of measures to mitigate the impacts of
construction activities as required by Sec. 51.308(f)(2)(iv)(B)
includes, in section 7.6 of the 2022 Nevada Regional Haze Plan, a
summary of measures that NDEP has implemented to mitigate the impacts
from such activities. Nevada manages the release of fugitive dust from
construction related activities through the implementation of
regulations set forth in the NAC. NDEP has implemented standards that
reduce fugitive dust emissions from construction,\104\ and requires an
ongoing program, using best practical methods, to prevent particulate
matter from becoming airborne. Additionally, a permit is required to
disturb or cover five acres or more of land and a dust control plan is
required for any disturbance greater than five acres for the Pahrump
Valley in southern Nevada.
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\104\ NAC 445B.22037.
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Pursuant to Sec. 51.308(f)(2)(iv)(C), source retirements and
replacement schedules are addressed in section 7.7 of the 2022 Nevada
Regional Haze Plan. Source retirements and replacements were considered
in developing the 2028 emissions projections, with on-the-books/on the
way retirements and replacements included in the 2028 projections.\105\
NDEP indicated that the State's continued implementation of NSR and PSD
requirements with FLM involvement for Class I area impact review will
protect the clearest days from further degradation and will assure that
no Class I areas experience degradation from expansion or growth of a
single new source or large-scale regional development of stationary
sources.
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\105\ The 2028OTBa2 emissions scenario in the WRAP modeling
includes reductions due to ``on-the-way'' and ``on-the-books''
controls, consent decree reductions, SIP control measures, and other
relevant regulations that have gone into effect since 2014 or will
go into effect before the end of 2028.
---------------------------------------------------------------------------
In considering smoke management as required in 40 CFR
51.308(f)(2)(iv)(D), NDEP explained, in section 7.8 of the 2022 Nevada
Regional Haze Plan, that it addresses smoke management through open
burning regulations found in NAC 445B.22067. Open burn rules apply to
federal, state, and private lands equally and prohibit open burning of
combustible refuse, waste, garbage, oil or open burning for any salvage
operation. Additionally, the Nevada Smoke Management Program \106\ was
developed to coordinate and facilitate the statewide management of
prescribed outdoor burning. This program is designed to meet the
requirements of Nevada's air quality statutes administered by NDEP and
compliance is achieved through a Memorandum of Understanding (MOU)
between the various state and federal agencies that conduct prescribed
burning, including the U.S. Bureau of Land Management, the U.S. Forest
Service, the U.S. National Park Service, the U.S. Fish and Wildlife
Service and Nevada state land management agencies. The signers of the
MOU wrote a collaborative document, the Smoke Management Plan,\107\
which details the applicability of the program and responsibilities of
affected parties, provides information on open burn authorization
requirements for those land managers using prescribed fire and wildland
fires for land management purposes, and includes information on air
quality monitoring at prescribed fires, burner qualifications and
emissions reduction methods.
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\106\ The program meets Nevada's air quality statutes in Nevada
Revised Statutes (NRS) 445B.100 through 445B.845. The program does
not, however, supersede the authority of local governments to
regulate and control smoke and air pollution under NRS 244.361 and
NRS 268.410 or the authority of the state forester to regulate
controlled fires under NRS 527.122 through 527.128.
\107\ Available at https://ndep.nv.gov/uploads/air-pollutants-docs/smp-2013-final.pdf.
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NDEP considered the anticipated net effect of projected changes in
emissions as required by Sec. 51.308(f)(2)(iv)(E) by discussing, in
section 7.9 of the 2022 Nevada Regional Haze Plan, the photochemical
modeling for the period of 2014 through 2028. The two modeling cases
run were a 2028 base case, which considered only on-the-books controls,
and a 2028 control case that considered implementation of the known
controls, such as the implementation of existing federal and state
regulations, existing SIP control measures and other relevant
regulations that have gone into effect since 2014 or will go into
effect before the end of 2028. NDEP discussed that the final 2028
visibility projection for Jarbidge Wilderness Area during the 20
percent most impaired days is 7.76 dv. The difference between the
second implementation period's baseline (7.97 dv) and RPG (7.76 dv), or
anticipated visibility improvement, is 0.21 dv.
7. Conclusion
The EPA reviewed NDEP's four-factor analyses and determinations of
controls necessary for reasonable progress in the 2022 Plan. As
explained in section
[[Page 48496]]
IV.E.2., NDEP relied on a Q/d threshold of five and 2014v2 emissions to
select sources to undergo the four-factor analysis requirement. This
analysis yielded eight point sources. NDEP further screened out three
sources from the four-factor analysis requirement based upon prior
shutdown of RGGS, emissions control beyond the scope of the State's
authority for the McCarran International Airport, and existing BACT
controls for TS Power Plant. The five remaining sources underwent
NDEP's four-factor analysis and control determination process. We find
that NDEP reasonably evaluated the sources that currently drive
visibility impairment within the state, and that NDEP adequately
explained and supported its decision to screen out three sources.
NDEP submitted numerous four-factor analyses and demonstrated that
its determination of controls necessary for reasonable progress was
based its consideration of the four statutory factors. Notably, NDEP's
$10,000 cost per ton threshold is one of the highest cost thresholds
established by any state for evaluating controls for the regional haze
program. NDEP also evaluated whether existing control measures are
necessary to make reasonable progress. Finally, the State incorporated
the selected measures into enforceable permit conditions and submitted
these for SIP approval. Accordingly, we are proposing to determine that
the Plan satisfies the requirements of 40 CFR 51.308(f)(2)(i) and CAA
section 169A(g)(1) to evaluate and determine the emissions reduction
measures that are necessary to make reasonable progress by considering
the four statutory factors.
We have also reviewed the Plan with respect to the remaining
requirements of Sec. 51.308(f)(2). As described in section IV.E.6.,
NDEP participated in the WRAP RHPWG and engaged in direct state-to-
state consultations with other states. NDEP is not relying on any
neighboring state's emissions reductions to achieve reasonable progress
at its Class I area, Jarbidge Wilderness Area, and no neighboring
states are relying on emissions reductions in Nevada to achieve
reasonable progress in their state Class I areas. For these reasons, we
propose to determine that NDEP has satisfied the consultation
requirements of Sec. 51.308(f)(2)(ii).
Based on the extensive documentation provided by the State of its
analyses and supporting analyses conducted by the WRAP, we also propose
to find that the Plan satisfies the requirements of 40 CFR
51.308(f)(2)(iii). We also propose to find that Nevada reasonably
satisfied the requirements to consider the five additional factors of
40 CFR 51.308(f)(2)(iv) in developing its long-term strategy, as
described in the section IV.E.6. Finally, we propose to find that NDEP
has satisfied the requirement of Sec. 51.308(f)(2) for the long-term
strategy to ``include the enforceable emissions limitations, compliance
schedules, and other measures that are necessary to make reasonable
progress, as determined pursuant to (f)(2)(i) through (iv)'', by
submitting the relevant permit conditions and regulations for approval
into the SIP.
Furthermore, we note that, it is now the EPA's policy that, where
visibility conditions for a Class I Federal area impacted by a state
are below the 2028 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.\108\ In
developing the regulations required by CAA section 169A(b), the EPA
established the concept of the URP for each Class I area. The URP is
determined by drawing a straight line from the measured 2000-2004
baseline conditions (in deciviews) for the 20 percent most impaired
days at each Class I area to the estimated natural conditions (in
deciviews) for the 20 percent most impaired days in 2064. From this
calculation, a URP value can be calculated for each year between 2004
and 2064. The EPA developed the URP to address the diverse concerns of
Eastern and Western states and account for the varying levels of
visibility impairment in Class I areas around the country while
ensuring an equitable approach nationwide. For each Class I area,
states must calculate the URP for the end of each planning period
(e.g., in 2028 for the second planning period).\109\ States may also
adjust the URP to account for impacts from anthropogenic sources
outside the United States and/or impacts from certain wildland
prescribed fires.\110\ Then, for each Class I area, states must compare
the reasonable progress goal (RPG) for the 20 percent most impaired
days to the URP for the end of the planning period. If the RPG is above
the URP, then an additional ``robust demonstration'' requirement is
triggered for each state that contributes to that Class I area.\111\
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\108\ See, e.g., 90 FR 29737, 29738 (July 7, 2025); 90 FR 20425,
20434 (May 14, 2025).
\109\ 40 CFR 51.308(f)(1)(vi)(A). We note that RPGs are a
regulatory construct that we developed to address the statutory
mandate in CAA section 169B(e)(1), which required our regulations to
include ``criteria for measuring `reasonable progress' toward the
national goal.'' Under 40 CFR 51.308(f)(3)(ii), RPGs measure the
progress that is projected to be achieved by the control measures a
state has determined are necessary to make reasonable progress.
Consistent with the 1999 RHR, the RPGs are unenforceable, though
they create a benchmark that allows for analytical comparisons to
the URP and mid-implementation-period course corrections if
necessary. 82 FR 3091-3092 (January 10, 2017).
\110\ 40 CFR 51.308(f)(1)(vi).
\111\ 40 CFR 51.308(f)(3)(ii).
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Projected 2028 visibility conditions at Nevada's one Class I area
and at other Class I areas identified by NDEP as being impacted by
emissions from Nevada, are below the URP. There is one Class I area in
a neighboring state, Sycamore Canyon in Arizona, where 2028 visibility
conditions for the most impaired days are projected to be above the
URP.\112\ However, Nevada did not identify Sycamore Canyon as being
potentially affected by emissions from Nevada, based on WRAP source
apportionment modeling. Moreover, the IMPROVE monitor for Sycamore
Canyon was moved in 2015 (from SYCA1 to SYCA2), which creates
uncertainty with respect to using data from the original monitor and
the new monitor together to calculate visibility trends, and to
comparing the 2028 model-projected Reasonable Progress Goal to the URP.
As explained in the Arizona Regional Haze Plan, ``a significant
increase in soil and coarse mass extinction (two locally derived
visibility impairing pollutants due to their limited transportability)
occurred following the monitor's relocation.'' \113\ Arizona further
noted that:
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\112\ Arizona Department of Environmental Quality, ``State
Implementation Plan Revision: Regional Haze Program (2018-2028)''
(August 15, 2022) (``2022 Arizona Regional Haze Plan''), p. 102.
\113\ Id.
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The impacts of monitor relocation on long-term trends of certain
visibility impairing species such as coarse mass and soil (which are
generally are more localized in impact due to their transportability)
may call into question the representativeness of a monitor located
outside of the Class I area, as is the case for SYCA_RHTS, when
assessing Class I area visibility. This is especially true of the new
SYCA2 IMPROVE monitoring site which is closely located to a small
residential community and near dirt roads.\114\
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\114\ Id. at 105.
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The EPA reviewed ADEQ's analyses and WRAP modeling regarding the
Sycamore Canyon sites and conducted additional analyses of the
monitoring data from the Sycamore Canyon and other monitoring sites in
Arizona. These analyses show that there was a large increase in coarse
mass and fine soil extinction after 2015 at SYCA2 that did not occur at
other sites in Arizona. This divergence between SYCA2 and other
[[Page 48497]]
monitors across the state indicates that the increase in coarse mass
and fine soil extinction is likely due to local sources of coarse mass
and fine soil at SYCA2 compared to SYCA1. Moreover, the increase was
not consistent with modeled emissions changes in the WRAP multistate
modeling domain and in Nevada occuring between 2014 and 2028, and not
consistent with the transport of pollutants from Nevada. By contrast,
the decreases in sulfate and nitrate extinction that were observed in
the Sycamore Canyon monitoring through 2023, and that were predicted in
the WRAP modeling of 2028, were consistent with emissions changes used
in the modeling, and with greater progress in visibility than the
glidepath. Data from the WRAP source apportionment modeling shows that
in spite of recent observed increases in visibility impairment
(primarily due to coarse mass and fine soil components), model-
estimated US anthropogenic impairment is expected to be reduced by
approximately 58 percent in 2028, compared to the 2000-2004 baseline.
This is far more than the 40 percent reduction in impairment that would
be required by the URP calculation between 2004 and 2028 to stay below
the glidepath. Thus, given the modeled and monitored decrease in
extinction from sulfate, nitrate, and organic matter, it is uncertain
whether visibility impairment at Sycamore Canyon will be above the 2028
glidepath. Moreover, to the extent visibility impairment at Sycamore
Canyon is above the 2028 glidepath, the available evidence indicates
that this is due to local sources in Arizona, not Nevada. The EPA's
analysis of impacts of Nevada's emissions on Sycamore Canyon is
described in more detail in a memo included in the docket for this
rulemaking action.\115\
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\115\ Memorandum September 4, 2025, from Scott Bohning, (EPA) to
File/Rulemaking Docket EPA-R09-OAR-2025-0101, Subject: ``Impact of
Emissions from Nevada on Sycamore Canyon.''
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Finally, we note that, while the EPA's policy establishes a
presumption regarding areas that are projected to be below the URP,
states whose emissions contribute to impairment in areas above the URP
can still meet the applicable requirements of the CAA and the RHR.
Indeed, the RHR specifically addresses this situation by requiring a
``robust demonstration'' that there are no additional emissions
reduction measures at contributing sources that would be reasonable to
include in the long-term strategy.'' \116\ We address Nevada's
compliance with this requirement in section IV.F. of this document.
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\116\ 40 CFR 51.308(f)(3)(ii)(B).
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In sum, Nevada selected a number of sources, evaluated emissions
control measures, considered the four statutory factors, and determined
that several existing and new controls were necessary to make
reasonable progress. In addition, with the possible exception of
Sycamore Canyon, all Class I areas in Nevada and neighboring states are
at or below the glidepath. For the foregoing reasons, we propose to
find that the Plan meets the requirements of 40 CFR 51.308(f)(2).
F. Reasonable Progress Goals
Section 51.308(f)(3) contains the requirements pertaining to RPGs
for each Class I area. Because Nevada is host to a Class I area, it is
subject to both Sec. 51.308(f)(3)(i) and, potentially, to (ii).
Section 51.308(f)(3)(i) requires a state in which a Class I area is
located to establish RPGs--one each for the most impaired and clearest
days--reflecting the visibility conditions that will be achieved at the
end of the implementation period as a result of the emissions
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. 40
CFR 51.308(f)(3)(ii) applies in circumstances in which a Class I area's
RPGs 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 emissions reduction measures for anthropogenic sources or
groups of sources in the state that would be reasonable to include in
its long-term strategy. Section 51.308(f)(3)(ii)(B) requires that if a
state contains sources that are reasonably anticipated to contribute to
visibility impairment in a Class I area in another state, and the RPG
for the most impaired days in that Class I area is above the URP, the
upwind state must provide the same demonstration.
NDEP's 2028 RPGs for the clearest and most impaired days at
Jarbidge were set at 1.72 and 7.76 deciviews, respectively, in the 2022
Nevada Regional Haze Plan.\117\ These values were based on WRAP
photochemical modeling results, with adjustments to account for updated
emissions estimates by NDEP, and emissions reductions from controls in
the State's long-term strategy, summarized in Chapter 6 table 6-1 of
the 2022 Nevada Regional Haze Plan. Appendix H of the 2022 Regional
Haze Plan details how the SO2 and NOX emissions
reductions were used to scale WRAP modeled extinction as used in the
IMPROVE equation, then summed and converted to deciviews.
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\117\ 2022 Nevada Regional Haze Plan, table 6-3.
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NDEP incorporated the long-term strategy emissions controls in the
RPG for the 20 percent most impaired days (MID) by scaling WRAP
modeling results.\118\ NDEP first, for both SO2 and
NOX, calculated the ratio of the EGU emissions reduction at
the North Valmy and Tracy plants, and the non-EGU emissions reduction
at the Apex and Fernley Plants, to the respective EGU and non-EGU
sector emissions that were used in WRAP visibility modeling for 2028.
Second, NDEP used the calculated SO2 and NOX
ratios to scale the modeled average MID contribution of the respective
sectors to ammonium sulfate and nitrate light extinction at the
Jarbidge Wilderness Area on MID. (These contributions were available
from the WRAP source apportionment modeling.) The resulting new total
light extinction was then converted to deciviews that reflect the
controls. This approach used average extinction over the MID days and
then computed deciviews, Finally, to account for this difference in
deciviews calculation order, NDEP applied a correction factor, the
ratio of corresponding quantities available on the WRAP TSS website
(deciviews from MID-average extinction, and MID-average deciviews). The
result was the RPG for MID, an estimate of
[[Page 48498]]
deciviews on most impaired days for 2028 that reflects the controls.
---------------------------------------------------------------------------
\118\ For all of the western Class I areas, the WRAP performed
preliminary 2028 visibility projections and compared them to the
2028 URP using the 2028OTBa2 and PAC2 CAMx modeling results and the
old and new IMPROVE equations. The 2028OTBa2 inventory included
emission reductions due to known controls (i.e., implementation of
existing federal and state regulations), existing SIP control
measures and other relevant regulations that have gone into effect
since 2014 or will go into effect before the end of 2028. Nevada
quantified additional emission reductions achieved through
reasonable progress controls and used them to determine the RPGs,
using 2028OTBa2 as a foundation. We also note that Nevada indicated
that the PAC2 WRAP modeling scenario included some potential
measures from other WRAP states. However, Nevada did not use the
projected 2028 visibility conditions at Jarbidge Wilderness Area
from the PAC2 modeling scenario as RPGs.
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For the 20 percent clearest days, NDEP used a slightly different
scaling procedure, since only total extinction was available for
sulfate and nitrate, not individual EGU and non-EGU extinction (i.e.,
source apportionment modeling was not done for the clearest days). For
both sulfate and nitrate, NDEP assumed that controls would reduce the
clearest day total extinction in the same proportion that it did for
the most impaired days. NDEP took the resulting scaled extinctions and
converted them to deciviews, and applied a correction factor, in the
same way as it did for the MID. The result was the RPG for the clearest
days, an estimate of deciviews on the clearest days for 2028 that
reflects the controls included in the long-term strategy.
Although NDEP's RPGs in the 2022 Nevada Regional Haze Plan
accounted for emissions associated with then-anticipated shutdown of
North Valmy Generating Station Units 1 and 2, NDEP noted that the
resulting changes to the RPGs were ``lost in rounding (still 7.76 dv
for most impaired days and 1.72 dv for clearest days).'' \119\ Thus,
regardless of the withdrawal of the enforceable shutdown of those
units, NDEP's RPGs for Jarbidge of 7.76 deciviews for the most impaired
days and 1.72 for the clearest days still reflect the visibility
conditions that will be achieved at the end of the implementation
period as a result of the NDEP's long-term strategy (as well as
implementation of other CAA requirements) consistent with 40 CFR
51.308(f)(3)(i). The value of the adjusted URP in 2028 for the Jarbidge
Wilderness Area is 8.2 deciviews.\120\ Nevada's RPG of 7.76 deciviews
for the most impaired days is thus below the adjusted URP and the
demonstration requirement under Sec. 51.308(f)(3)(ii)(A) is not
triggered. In addition, the RPG of 1.72 for the clearest days is below
the 2000-2004 baseline visibility conditions of 2.56 deciviews on the
20 percent clearest days. Therefore, the long-term strategy and the
RPGs provide for an improvement in visibility for the most impaired
days since the baseline period and ensure no degradation in visibility
for the clearest days since the baseline period consistent with 40 CFR
51.308(f)(3)(i).
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\119\ 2022 Nevada Regional Haze Plan, p. 6-5.
\120\ 2022 Nevada Regional Haze Plan, section 6.9.3. The 2028
URP glide path value of 8.2 dv is interpolated between the baseline
2004-2004 value of 8.7 dv and the adjusted 2064 URP endpoint of 7.4
dv.
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Under Sec. 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 Sec. 51.308(f)(3)(ii)(B) must demonstrate that
there are no additional emissions reduction measures that would be
reasonable to include in its long-term strategy. NDEP explained in the
Plan that the no neighboring states are relying on emissions reductions
in Nevada to achieve reasonable progress in any of their Class I areas.
In addition, NDEP conducted ``URP Glidepath checks'' for several out-
of-state Class I areas that were specifically identified as being
affected by emissions originating in Nevada (Grand Canyon, Arizona;
Ike's Backbone, Arizona; Desolation Wilderness, California; Craters of
the Moon, Idaho; Hells Canyon, Oregon; and Zion Canyon, Utah).\121\
NDEP confirmed that projected visibility in 2028 (2028OTBa2) for the 20
percent most impaired days for each area fall below the adjusted
glidepath.\122\ In addition, as described in section IV.E.7. of this
document, while the RPG for Sycamore Canyon in Arizona is above the
adjusted glidepath, it is it reasonable to conclude that sources in
Nevada are not the cause of this. Because Nevada did not determine that
its sources contribute to impairment in Sycamore Canyon, it did not
expressly make a robust demonstration under 40 CFR 51.308(f)(3)(ii)(B).
However, as previously noted, NDEP submitted a robust long-term
strategy, including numerous well-documented four-factor analyses and
required new controls at multiple sources based on the outcome of these
analyses. Accordingly, we find that there are no additional emissions
reduction measures for anthropogenic sources or groups of sources in
the State that may reasonably be anticipated to contribute to
visibility impairment in the Class I area that would be reasonable to
include in its own long-term strategy. Therefore, if a robust
demonstration were required, the Plan would have met this requirement
as well.
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\121\ Id. section 6.9.4.
\122\ Id. For this analysis, NDEP employed adjustments for
international emissions and prescribed fire determined by WRAP in
accordance with EPA guidance, as described in section IV.D of this
document.
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For the foregoing reasons, the EPA proposes to determine that
Nevada has satisfied the applicable requirements of 40 CFR 51.308(f)(3)
relating to RPGs.
G. Additional Monitoring To Assess Reasonably Attributable Visibility
Impairment
The EPA and FLMs have not previously advised Nevada that additional
monitoring is needed to assess reasonably attributable visibility
impairment. Therefore, the requirements under 40 CFR 51.308(f)(4) are
not applicable to Nevada.
H. Monitoring Strategy and Other Implementation Plan Requirements
Section 51.308(f)(6) specifies that each comprehensive revision of
a state's regional haze plan must contain or provide for certain
elements, including monitoring strategies, emissions inventories, and
any reporting, recordkeeping, and other measures needed to assess and
report on visibility. A main requirement of this section is for states
with Class I areas to submit monitoring strategies for measuring,
characterizing, and reporting on visibility impairment. Compliance with
this requirement may be met through participation in the IMPROVE
network.
According to section 1.4.1.1 of the 2022 Nevada Regional Haze Plan,
two operating IMPROVE monitoring sites are located in Nevada, one at
Great Basin National Park and the other at the Jarbidge Wilderness
Area. Additionally, the Walker River Paiute Tribe, a third monitoring
site in Nevada, operated from June 2003 to November 2005. The IMPROVE
monitor representing the air quality at the Jarbidge Wilderness Area is
identified as JARB1 in the IMPROVE monitoring network database. Nevada
indicates that generally, JARB1 is expected to be representative of
aerosol characteristics in the Jarbidge Wilderness Area especially when
the atmosphere is well mixed and regionally homogeneous. However, the
site is at a low elevation in the Jarbidge River Canyon that is
separate from the Jarbidge Wilderness Area and upper East Fork of the
Jarbidge River. Consequently, the monitoring site may at times be
isolated from wilderness locations and potentially impacted by
different local emissions sources.
Section 51.308(f)(6)(i) requires SIPs to provide for the
establishment of any additional monitoring sites or equipment needed to
assess whether RPGs to address regional haze for all mandatory Class I
Federal areas within the state are being achieved. JARB1 was among the
first 20 IMPROVE sites to start operation in 1988 and is sponsored by
the U.S. Forest Service. Nevada indicates in section 8.4 that the JARB1
IMPROVE site representing Nevada's Class I area at the Jarbidge
Wilderness Area is considered to be sufficiently representative to
support a determination of reasonable progress for the Jarbidge
Wilderness Area.
Section 51.308(f)(6)(ii) requires SIPs to provide for procedures by
which
[[Page 48499]]
monitoring data and other information are used in determining the
contribution of emissions from within the state to regional haze
visibility impairment at mandatory Class I Federal areas both within
and outside the state. The 2022 Nevada Regional Haze Plan indicates
that generally, the WRAP has analyzed, deduced, and provided
information on relative contributions to visibility impairment. Nevada
also indicates that it has and will continue to use data reported by
the IMPROVE program as input into the regional technical support
analysis tool found at the Visibility Information Exchange Web System
and WRAP's Technical Support System, as well as other analysis tools
and efforts sponsored by the WRAP. Nevada will continue to participate
in the regional analysis activities of the WRAP to collectively assess
and verify the progress toward RPGs, as the RHR is implemented.
Section 51.308(f)(6)(iii) does not apply to Nevada, as it has a
Class I area.
Section 51.308(f)(6)(iv) requires the SIP to provide for the
reporting of all visibility monitoring data to the Administrator at
least annually for each Class I area in the state. As noted above, the
JARB1 IMPROVE monitor is located within the Jarbidge Wilderness Area
and is operated and maintained by the U.S. Forest Service. The
monitoring strategy for Nevada relies upon the continued availability
of the IMPROVE network.
Section 51.308(f)(6)(v) requires SIPs to provide for a statewide
inventory of emissions of pollutants that are reasonably anticipated to
cause or contribute to visibility impairment, including emissions for
the most recent year for which data are available and estimates of
future projected emissions. It also requires a commitment to update the
inventory periodically. Nevada indicates that it has prepared a
statewide inventory of emissions that can reasonably be expected to
cause or contribute to visibility impairment in mandatory Class I areas
with the support of the WRAP.\123\
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\123\ 2022 Nevada Regional Haze Plan, chapter 3.
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Section 51.308(f)(6)(v) also requires states to include estimates
of future projected emissions and include a commitment to update the
inventory periodically. Nevada also committed to updating its statewide
emissions inventory periodically, and the updates will be used for
state tracking of emission changes, determining trends and providing
input into the WRAP's evaluation of whether RPGs are being achieved, as
well as other regional analyses. Nevada will also depend upon and
participate in additional periodic collective emissions inventory
efforts by the WRAP.
The EPA proposes to find that Nevada has met the requirements of 40
CFR 51.308(f)(6) as described above, including through its continued
participation in the IMPROVE network, continued inventory work with the
WRAP, and commitment to update the inventory periodically, and that no
further elements are necessary at this time for Nevada to assess and
report on visibility pursuant to 40 CFR 51.308(f)(6)(vi).
I. Requirements for Periodic Reports Describing Progress Towards the
Reasonable Progress Goals
40 CFR 51.308(f)(5) requires that periodic comprehensive revisions
of states' regional haze plans also address the progress report
requirements of 40 CFR 51.308(g)(1)-(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.
Sections 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 emissions reductions achieved through implementation of those
measures. Section 51.308(g)(3) applies only to states with Class I
areas within their borders and requires such states to assess current
visibility conditions, changes in visibility relative to baseline
(2000-2004) visibility conditions, and changes in visibility conditions
relative to the period addressed in the first implementation period
progress report. 40 CFR 51.308(g)(4) applies to all states and requires
an analysis tracking changes in emissions of pollutants contributing to
visibility impairment from all sources and sectors since the period
addressed by the first implementation period progress report. This
provision further specifies the year, or years, through which the
analysis must extend depending on the type of source and the platform
through which its emissions 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.
Section 51.308(f)(5) specifies that a progress report submitted as
part of a comprehensive regional haze SIP revision must address the
time period since the most recent progress report. Nevada submitted the
most recent 5-year progress report to EPA in November 2014, which
presented data analysis for the period 2008 through 2012 and 2018 RPGs.
Therefore, for Nevada, the time period required to be addressed in the
progress report under the second planning period SIP began in 2013.
The 2022 Nevada Regional Haze Plan also describes the status of
measures of the long-term strategy from the first implementation
period.\124\ During the first planning period for regional haze,
programs that were put in place required control measures installed and
operating by January 1, 2015, and focused on four sources, comprising
10 units--NV Energy's generating stations at Tracy (units 1, 2 and 3),
Fort Churchill (units 1 and 2) and Reid Gardner (units 1, 2 and 3); and
Southern California Edison's (SCE) Mohave Generating Station (units 1
and 2). Additionally, as mentioned in section IV.A., the EPA
promulgated a FIP for RGGS in 2012 that was later rescinded in 2018 due
to the shutdown of the facility. For Mohave Generating Station, Nevada
describes that the facility was fully decommissioned and demolished and
the operating permit for the facility was officially cancelled in April
2010. For NV Energy, Nevada describes that the Public Utilities
Commission of Nevada granted approval for Tracy Units 1 and 2 to be
retired, and approval to implement alternative equivalent control
technology for BART and supplemental control technology for Unit 3 at
Tracy and Units 1 and 2 at Fort Churchill. NV Energy retired Units 1
and 2 on December 31, 2014, and Nevada subsequently removed them from
the Title V operating permit. Tracy Unit 3 discontinued the occasional
use of distillate fuel and was retrofitted with the best available Low-
NOX Burners before the compliance deadline. For Fort
Churchill Units 1 and 2, the use of fuel oil has since been permanently
suspended at the facility.
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\124\ 2022 Nevada Regional Haze Plan, section 6.10.2.1.
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The 2022 Nevada Regional Haze Plan also contains a summary of the
emissions from the long-term strategy from the first implementation
period, comparing emissions of NOX, SO2, and
PM10 at BART facilities for years 2008
[[Page 48500]]
and 2018.\125\ All BART sources show total emissions reductions, except
for Mohave, which has emissions of 0 tpy for all pollutants in the
analysis due to ceasing operations in 2005.
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\125\ Id. section 6.10.2.2 and table 6-6.
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The EPA proposes to find that Nevada has met the requirements of 40
CFR 51.308(g)(1) and (2) because the Plan describes the measures
included in the long-term strategy from the first implementation
period, as well as the status of their implementation and the emissions
reductions achieved through such implementation.
The 2022 Nevada Regional Haze Plan included summaries of the
visibility conditions and the trend of the 5-year averages through 2018
at the Jarbidge Wilderness Area.\126\ The Plan included the 5-year
baseline (2000-2004) visibility conditions for the clearest and most
impaired days of 2.56 and 8.73 deciviews, respectively. The status of
the 2008-2012 period for the clearest and most impaired days are 1.84
and 7.88 deciviews, respectively. The Plan also included the current 5-
year status (2014-2018) for the clearest and most impaired days of 1.84
and 7.97 deciviews, respectively. The EPA therefore proposes to find
that Nevada has satisfied the requirements of 40 CFR 51.308(g)(3).
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\126\ 2022 Nevada Regional Haze Plan, tables 2-1 and 2-2 and
figures 2-4 and 2-5.
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The 2022 Nevada Regional Haze Plan also addresses 40 CFR
51.308(g)(3)-(5).\127\ Specifically, chapter 2 addresses the
requirements of 40 CFR 51.308 (g)(3), chapter 3 addresses the
requirements of 40 CFR 51.308(g)(4), and chapter 4 addresses the
requirements of 40 CFR 51.308(g)(5). In the 2023 Nevada Regional Haze
Technical Supplement, NDEP also provided additional supporting
information to address the requirements of 40 CFR 51.308(g)(4)-(5).
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\127\ 2022 Nevada Regional Haze Plan, table 6-7.
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Pursuant to Sec. 51.308(g)(4), NDEP provided a summary of
emissions of NOX, SO2, PM10,
PM2.5, VOC, and NH3 from all sources and
activities, including from point, nonpoint, non-road mobile, and on-
road mobile sources for the progress report period, for NEI years 2002,
2005, 2008, 2011, 2014, and 2017. NDEP also provided 2013-2019 Clean
Air Markets Program Data (CAMPD) data for all sources with emissions of
visibility impairing pollutants. The reductions achieved by Nevada
emissions control measures are seen in the emissions inventory and
visibility progress. The EPA is therefore proposing to find that Nevada
has met the requirements of Sec. 51.308(g)(4) by providing emissions
information for NOX, SO2, PM10,
PM2.5, VOC, and NH3 broken down by type of
sources and activities within the state.
Pursuant to Sec. 51.308(g)(5), Nevada provided an assessment of
any significant changes in anthropogenic emissions within or outside
the state that have occurred since the period, including whether or not
these changes in anthropogenic emissions were anticipated in that most
recent plan, and whether they have limited or impeded progress in
reducing pollutant emissions and improving visibility. NDEP noted
overall reductions of 62 percent SO2, 5 percent
PM10, 60 percent VOC, and 17 percent PM2.5 when
comparing 2014 with 2017 NEI data. NDEP noted emissions increases of 18
percent NOX, 68 percent NH3, and 17 percent
PM2.5 when comparing 2014 with 2017 NEI data. For these
emissions increases, NDEP concluded that these increases are largely
driven by increases in biogenic emissions. Nevada had a more intense
wildfire season in 2017, where nearly 1.2 million acres were burned by
wildfire, compared to roughly 80,000 acres burned in 2014. NDEP also
noted increases in fertilizer application that affected NH3
emissions and commercial cooking that affected PM2.5
emissions. NDEP also noted that these increases have not limited or
impeded visibility progress. NDEP further reported overall reductions
of 34 percent NOX and 38 percent SO2 in CAMPD EGU
emissions during the progress report period. NDEP indicated that these
reductions have met or exceeded the downward trend predicted from the
regional haze plan in the first round. The EPA is therefore proposing
to find that Nevada has met the requirements of Sec. 51.308(g)(5).
J. 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 emissions reduction obligation so that information and
recommendations provided by the FLMs can meaningfully inform the
state's decisions on its long-term strategy. If the consultation has
taken place at least 120 days before a public hearing or public comment
period, the opportunity for consultation will be deemed early enough.
Regardless, the opportunity for consultation must be provided at least
sixty days before a public hearing or public comment period at the
state level. 40 CFR 51.308(i)(2) also provides two substantive topics
on which FLMs must be provided an opportunity to discuss with states:
assessment of visibility impairment in any Class I area and
recommendations on the development and implementation of strategies to
address visibility impairment. 40 CFR 51.308(i)(3) requires states, in
developing their implementation plans, to include a description of how
they addressed FLMs' comments.
Sections 9.1 and 9.2 of the 2022 Nevada Regional Haze Plan
describes the coordination and consultation with FLMs. Nevada indicates
in section 9.1.1 that Nevada has provided agency contacts to the FLMs
as required in 40 CFR 51.308(i)(1). The section also describes past
coordination and consultation with FLMs during the development of the
2022 Nevada Regional Haze Plan in accordance with the provisions of
Sec. 51.308(i)(2). Numerous opportunities were provided by the WRAP
for FLMs to participate in the development of technical documents
developed by the WRAP, such as the opportunity to review and comment on
analyses, reports, and policies, and opportunities for coordination and
consultation with FLMs through tele-meetings and stakeholder outreach.
The FLM consultation process included the opportunity to discuss their
assessment of visibility impairment at the Jarbidge Wilderness Area and
to provide recommendations on RPGs and the development and
implementation of visibility control strategies.
Section 9.1.1.1 of the 2022 Nevada Regional Haze Plan describes the
formal FLM consultation process. A draft version of the 2022 Nevada
Regional Haze Plan was submitted to the FLMs \128\ on November 29,
2021, for a 60-day review and comment period. Comments were received
from the National Parks Service and U.S. Forest Service on February 15,
2022. The U.S. Fish and Wildlife Service and Bureau of Land Management
did not submit any comments as a result of the formal consultation
period and expressed support for the contents of the draft SIP. As
required by CAA 169A(d), Nevada indicates that the 2022 Nevada Regional
Haze Plan also contained a summary of
[[Page 48501]]
conclusions and recommendations of the FLMs as part of the SIP
submission made available for public comment, along with a summary of
how Nevada has addressed all comments and requests submitted by the
FLMs, as required by 40 CFR 51.308(i)(3). NDEP's final response to
comments received during the formal FLM consultation is provided in
appendix C.
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\128\ Nevada indicates that FLMs consist of the National Parks
Service, U.S. Fish and Wildlife Service, U.S. Forest Service, and
the Bureau of Land Management.
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Section 9.2 of the 2022 Nevada Regional Haze Plan describes future
coordination and consultation commitments. As required by 40 CFR
51.308(i)(4), Nevada indicates that it will continue to coordinate and
consult with the FLMs during the development of future progress reports
and plan revisions. The progress reports are to occur at five-year
intervals, with the first report due five years from submittal of the
initial RH SIP. Plan revisions are due every ten years, with the
exception of the second SIP revision and subsequent progress report.
The consultation process will provide on-going and timely opportunities
to address the status of the control programs identified in this SIP,
the development of future assessments of sources and impacts, and the
development of additional control programs. Nevada will also provide
the FLMs an opportunity to review and comment on future SIP revisions
and the 5-year progress reports.
For the reasons stated above, the EPA proposes to find that Nevada
has satisfied the requirements under 40 CFR 51.308(i) and CAA 169A(d)
to consult with the FLMs on its regional haze SIP for the second
implementation period and to include a summary of the FLMs' conclusions
and recommendations in the notice to the public.
The 2022 Nevada Regional Haze Plan includes a commitment to submit
a regional haze SIP revision by July 31, 2028, and every ten years
thereafter in section 9.5. NDEP also committed to submit periodic
progress reports in accordance with Sec. 51.308(f) and evaluate
progress towards the RPG for each mandatory Class I Federal area
located within the state and in each mandatory Class I Federal area
located outside the state that may be affected by emissions from within
the state in accordance with Sec. 51.308(g).
V. Proposed Action
The EPA is proposing to approve the Plan as satisfying the regional
haze requirements for the second implementation period contained in 40
CFR 51.308(f). Specifically, we are proposing to approve the 2022
Nevada Regional Haze Plan (excluding the portions withdrawn on July 27,
2023) and appendix A of the 2025 SIP Supplement into the Nevada SIP.
Thus, the EPA is proposing to approve and incorporate by reference in
40 CFR 52.1470(d) (``EPA-approved State source-specific permits''), the
source-specific requirements listed below as part of Nevada's long-term
strategy for regional haze, and as summarized in table 8 of this
document.
NDEP Permit No. AP4911-0194.04 (for Tracy Generating
Station), Conditions IV.B.1.a, IV.B.3.f, IV.D.1.a, IV.D.3.f, IV.F.1,
IV.L.1.a, IV.L.3.g, IV.M.1.a, IV.M.3.g, V.A, and V.C.
Clark County DES Authority to Construct Permit for a Major
Part 70 Source, Source ID: 3 (for Lhoist North America Apex Plant),
Conditions 2.1.1, 2.2.1, 2.2.2, 2.2.3, 3.2.1, 3.2.2, 4.1, 4.3, 4.4.7,
4.4.8, 4.4.15, and 4.4.16.
NDEP Permit No. AP3274-1329.03 (for Graymont Pilot Peak
Plant), Conditions IV.K.1.a, IV.K.3.b, IV.K.4.q, IV.K.4.u, IV.N.1.a,
IV.N.3.b, IV.N.4.q, IV.N.4.u, V.S.1.a, IV.S.3.b, IV.S.4.q, IV.S.4.u,
and V.B-C.
Table 8--Regional Haze Long-Term Strategy Source-Specific Provisions
----------------------------------------------------------------------------------------------------------------
Name of source Permit No. State effective date Explanation
----------------------------------------------------------------------------------------------------------------
Lhoist North America Apex Plant... Clark County DES April 30, 2025............. Permit conditions 2.1.1,
Authority to 2.2.1, 2.2.2, 2.2.3,
Construct Permit 3.2.1, 3.2.2, 4.1, 4.3,
for a Major Part 70 4.4.7, 4.4.8, 4.4.15,
Source, Source ID: and 4.4.16.
3.
Graymont Pilot Peak Plant......... NDEP Permit No. June 14, 2024.............. Permit conditions
AP3274-1329.03. IV.K.1.a, IV.K.3.b,
IV.K.4.q, IV.K.4.u,
IV.N.1.a, IV.N.3.b,
IV.N.4.q, IV.N.4.u,
V.S.1.a, IV.S.3.b,
IV.S.4.q, IV.S.4.u, and
V.B-C.
Tracy Generating Station.......... NDEP Permit No. March 23, 2022............. Permit conditions
AP4911-0194.04. IV.B.1.a, IV.B.3.f,
IV.D.1.a, IV.D.3.f,
IV.F.1, IV.L.1.a,
IV.L.3.g, IV.M.1.a,
IV.M.3.g, V.A and V.C.
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VI. Incorporation by Reference
In this document, the EPA is proposing to include regulatory text
in an EPA final rule that includes incorporation by reference. In
accordance with requirements of 1 CFR 51.5, the EPA is proposing to
incorporate by reference the regulatory and source-specific provisions
described in section VI. of this preamble. The EPA has made, and will
continue to make, these materials generally available through https://www.regulations.gov and at the EPA Region 9 Office (please contact the
person identified in the FOR FURTHER INFORMATION CONTACT section of
this preamble for more information).
VII. Statutory and Executive Order Reviews
Under the CAA, the Administrator is required to approve a SIP
submission that complies with the provisions of the Act and applicable
federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in
reviewing SIP submissions, the EPA's role is to approve state choices,
provided that they meet the criteria of the Act. Accordingly, this
proposed action merely proposes to approve state law as meeting federal
requirements and does not impose additional requirements beyond those
imposed by state law. For that reason, this proposed action:
Is not a significant regulatory action subject to review
by the Office of Management and Budget under Executive Order 12866 (58
FR 51735, October 4, 1993);
Is not subject to Executive Order 14192 (90 FR 9065,
February 6, 2025) because SIP actions are exempt from review under
Executive Order 12866;
Does not impose an information collection burden under the
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
Is certified as not having a significant economic impact
on a substantial number of small entities under the Regulatory
Flexibility Act (5 U.S.C. 601 et seq.);
Does not contain any unfunded mandate or significantly or
uniquely affect small governments, as described
[[Page 48502]]
in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);
Does not have federalism implications as specified in
Executive Order 13132 (64 FR 43255, August 10, 1999);
Is not subject to Executive Order 13045 (62 FR 19885,
April 23, 1997) because it proposes to approve a state program;
Is not a significant regulatory action subject to
Executive Order 13211 (66 FR 28355, May 22, 2001); and
Is not subject to requirements of section 12(d) of the
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272
note) because application of those requirements would be inconsistent
with the CAA.
In addition, the SIP is not approved to apply on any Indian
reservation land or in any other area where the EPA or an Indian Tribe
has demonstrated that a Tribe has jurisdiction. In those areas of
Indian country, the rule does not have Tribal implications and will not
impose substantial direct costs on Tribal governments or preempt Tribal
law as specified by Executive Order 13175 (65 FR 67249, November 9,
2000).
List of Subjects in 40 CFR Part 52
Environmental protection, Air pollution control, Incorporation by
reference, Nitrogen dioxide, Ozone, Particulate matter, Sulfur oxides.
Authority: 42 U.S.C. 7401 et seq.
Dated: October 14, 2025.
Cheree D. Peterson,
Acting Regional Administrator, Region IX.
[FR Doc. 2025-19637 Filed 10-22-25; 8:45 am]
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