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Proposed Rule2026-03072

Partial Approval and Partial Disapproval of Air Quality Implementation Plans; Hawaii; Regional Haze State Implementation Plan for the Second Implementation Period

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Published

February 17, 2026

Issuing agencies

Environmental Protection Agency

Abstract

The Environmental Protection Agency (EPA) is proposing to partially approve and partially disapprove the regional haze state implementation plan (SIP) revision submitted by Hawaii on August 2, 2024, under the Clean Air Act (CAA) and the EPA's Regional Haze Rule (RHR) for the program's second implementation period. Hawaii's SIP submission is intended to 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 SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is proposing to approve the portions of Hawaii's submission relating to calculations of baseline, current, and natural visibility conditions, progress to date, the uniform rate of progress, reasonably attributable visibility impairment, progress report requirements, and monitoring strategy and other implementation plan requirements. The EPA is proposing to disapprove the long-term strategy, including the enforceable shutdown of several electric generating units at facilities on the islands of Hawaii and Maui. Additionally, we are proposing to disapprove the portions of the submission relating to reasonable progress goals and FLM consultation requirements.

Full Text

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<title>Federal Register, Volume 91 Issue 31 (Tuesday, February 17, 2026)</title>
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[Federal Register Volume 91, Number 31 (Tuesday, February 17, 2026)]
[Proposed Rules]
[Pages 7204-7222]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2026-03072]

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ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R09-OAR-2025-0152; FRL-12584-01-R9]

Partial Approval and Partial Disapproval of Air Quality
Implementation Plans; Hawaii; 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
partially approve and partially disapprove the regional haze state
implementation plan (SIP) revision submitted by Hawaii on August 2,
2024, under the Clean Air Act (CAA) and the EPA's Regional Haze Rule
(RHR) for the program's second implementation period. Hawaii's SIP
submission is intended to 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 SIP
submission also addresses other applicable requirements for the second
implementation period of the regional haze program. The EPA is
proposing to approve the portions of Hawaii's submission relating to
calculations of baseline, current, and natural visibility conditions,
progress to date, the uniform rate of progress, reasonably attributable
visibility impairment, progress report requirements, and monitoring
strategy and other implementation plan requirements. The EPA is
proposing to disapprove the long-term strategy, including the
enforceable shutdown of several electric generating units at facilities
on the islands of Hawaii and Maui. Additionally, we are proposing to
disapprove the portions of the submission relating to reasonable
progress goals and FLM consultation requirements.

DATES: Written comments must be received on or before April 20, 2026.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R09-
OAR-2025-0152 at <a href="https://www.regulations.gov">https://www.regulations.gov</a>. For comments submitted at
<a href="http://Regulations.gov">Regulations.gov</a>, follow the online instructions for submitting
comments. Once submitted, comments cannot be edited or removed from
<a href="http://Regulations.gov">Regulations.gov</a>. For either manner of submission, the EPA may publish
any comment received to its public docket. Do not submit electronically
any information you consider to be confidential business information
(CBI) or other information whose disclosure is restricted by statute.
Multimedia submissions (audio, video, etc.) must be accompanied by a
written comment. The written comment is considered the official comment
and should include discussion of all points you wish to make. The EPA
will generally not consider comments or comment contents located
outside of the primary submission (i.e., on the web, cloud, or other
file sharing system). For additional submission methods, please contact
the person identified in the FOR FURTHER INFORMATION CONTACT section.
For the full EPA public comment policy, information about CBI or
multimedia submissions, and general guidance on making effective
comments, please visit <a href="https://www.epa.gov/dockets/commenting-epa-dockets">https://www.epa.gov/dockets/commenting-epa-dockets</a>. 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.

FOR FURTHER INFORMATION CONTACT: Michael Dorantes, Geographic
Strategies and Modeling Section (AIR 2-2), EPA Region IX, 75 Hawthorne
Street, San Francisco, CA, telephone number: (415) 972-3934, email
address: <a href="/cdn-cgi/l/email-protection#781c170a19160c1d0b5615111b10191d14381d0819561f170e"><span class="__cf_email__" data-cfemail="573338253639233224793a3e343f36323b1732273679303821">[email&#160;protected]</span></a>.

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 Hawaii's Regional Haze Submission for
the Second Implementation Period
A. Background on the EPA's FIP for Hawaii in the First
Implementation Period
B. Hawaii's Second Implementation Period SIP Submission
C. Identification of Class I Areas
D. Calculations of Baseline, Current, and Natural Visibility
Conditions; Progress to Date; and the Uniform Rate of Progress
E. Long-Term Strategy for Regional Haze
F. Reasonable Progress Goals
G. Monitoring Strategy and Other Implementation Plan
Requirements
H. Requirements for Periodic Reports Describing Progress Towards
the Reasonable Progress Goals
I. Requirements for State and Federal Land Manager Coordination
V. Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is the EPA proposing?

On August 12, 2022, the Hawaii Department of Health (HDOH)
submitted a revision to its SIP, titled ``Hawaii State Department of
Health Regional Haze State Implementation Plan, Second Planning
Period'' to address regional haze for the second implementation
period.\1\ Then, on August 2, 2024,\2\ HDOH withdrew its original SIP
submission and simultaneously submitted a revised regional haze SIP
submission, titled ``Hawaii State Department of Health Regional Haze
State Implementation Plan, Revision 1, Second Planning Period''
(henceforth referred to as the ``2024 Hawaii Regional Haze Plan'' or
``the Plan'') for the second implementation period. HDOH 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. For
the reasons described in this document, the EPA is proposing to
partially approve and partially disapprove the 2024 Hawaii Regional
Haze Plan. Specifically, we are proposing to approve the elements of
the 2024 Hawaii Regional Haze Plan related to requirements contained in
40 CFR 51.308(f)(1), (f)(4) through (6), and (g)(1) through (5) and to
disapprove the elements of the 2024 Hawaii Regional Haze Plan related
to requirements contained in 40 CFR 51.308(f)(2), (f)(3),

[[Page 7205]]

and (i)(2) through (4). We are proposing to disapprove these elements
because Hawaii did not provide necessary assurances that the
unconsented closures in the long-term strategy would not violate
federal and possibly state law, as required by CAA section
110(a)(2)(E)(i). In particular, the EPA proposes to find that approval
by the EPA of unconsented source closures, without just compensation,
could violate the Takings Clause of the U.S. Constitution and possibly
comparable provisions of state law, and that Hawaii has not provided
the necessary assurances that such violations would not occur. The Plan
included the enforceable shutdown of a combined six boiler units at the
Kanoelehua-Hill and Kahului Generating Stations, on the islands of
Hawaii and Maui, respectively, and the option to shut down several
diesel engine generators at the Maalaea Generating Station on the
island of Maui. However, Hawaiian Electric, the owner of these units no
longer consents to their shutdown due to concerns that it would result
in potential energy reserve shortfalls which would endanger grid
reliability. Thus, the long-term strategy does not meet 110(a)(2)(E)(i)
and does not meet 40 CFR 51.308(f)(2). In the absence of an approved
long-term strategy, we also cannot approve the associated RPGs under 40
CFR 51.308(f)(3) or the FLM consultation requirements under
51.308(i)(2) through (4).
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\1\ Letter dated August 11, 2022, from Elizabeth Char, Director
of Health, Hawaii Department of Health, to Martha Guzman, Regional
Administrator, EPA Region IX (submitted electronically on August 12,
2022).
\2\ Letter dated August 2, 2024, from Kenneth Fink, Director of
Health, Hawaii Department of Health, to Martha Guzman, Regional
Administrator, EPA Region IX (submitted electronically on August 2,
2024).
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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 prior EPA proposal actions.\3\ 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.\4\ 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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\3\ See 90 FR 13516 (March 24, 2025).
\4\ See 82 FR 3078 (January 10, 2017).
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A. Regional Haze Background

In the 1977 CAA Amendments, Congress created a program for
protecting visibility in the nation's mandatory Class I Federal areas,
which include certain national parks and wilderness areas.\5\ CAA 169A.
The CAA establishes as a national goal the ``prevention of any future,
and the remedying of any existing, impairment of visibility in
mandatory class I Federal areas which impairment results from manmade
air pollution.'' \6\
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\5\ 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.
\6\ 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 (SO<INF>2</INF>), nitrogen oxides (NO<INF>X</INF>), and, in
some cases, volatile organic compounds (VOC) and ammonia
(NH<INF>3</INF>)). Fine particle precursors react in the atmosphere to
form fine particulate matter (PM<INF>2.5</INF>), which impairs
visibility by scattering and absorbing light. Visibility impairment
reduces the perception of clarity and color, as well as visible
distance.\7\
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\7\ There are several ways to measure the amount of visibility
impairment, i.e., haze. One such measurement is the deciview, which
is the principal metric used by the RHR. Under many circumstances, a
change in one deciview will be perceived by the human eye to be the
same on both clear and hazy days. The deciview is unitless. It is
proportional to the logarithm of the atmospheric extinction of
light, which is the perceived dimming of light due to its being
scattered and absorbed as it passes through the atmosphere.
Atmospheric light extinction (b\ext\) is a metric used for
expressing visibility and is measured in inverse megameters
(Mm<SUP>-1</SUP>).
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To address regional haze visibility impairment, the 1999 RHR
established an iterative planning process that requires both states in
which Class I areas are located and states ``the emissions from which
may reasonably be anticipated to cause or contribute to any impairment
of visibility'' in a Class I area to periodically submit SIP revisions
to address such impairment.\8\
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\8\ 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 revision); 64 FR 35714, 35768.
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On January 10, 2017, the EPA promulgated revisions to the RHR, that
apply for the second and subsequent implementation periods.\9\ 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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\9\ 82 FR 3078.
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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),\10\ which include
representation from state and tribal governments, the EPA, and Federal
Land Managers (FLMs), were developed in the lead-up to the first
implementation period to address regional haze. RPOs evaluate technical
information to better understand how emissions from State and Tribal
land impact Class I areas across the country, pursue the development of
regional strategies to reduce emissions of particulate matter and other
pollutants leading to regional haze, and help states meet the
consultation requirements of the RHR.
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\10\ RPOs are sometimes also referred to as ``multi-
jurisdictional organizations,'' or MJOs. For the purposes of this
notice, the terms RPO and MJO are synonymous.
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The Western Regional Air Partnership (WRAP),\11\ one of the five
RPOs described above, is a collaborative effort of state governments,
Tribal governments, and various Federal agencies established to
initiate and coordinate activities associated with the management of
regional haze, visibility, and other air quality issues in the 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.
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\11\ See <a href="https://www.wrapair2.org/">https://www.wrapair2.org/</a>.

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[[Page 7206]]

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

Under the CAA and EPA's regulations, all 50 states, the District of
Columbia, and the U.S. Virgin Islands are required to submit regional
haze 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.\12\ To this end, section 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 51.308(f)(1)
through (f)(3) generally mirroring the order of the steps in the
reasonable progress analysis \13\ and (f)(4) through (f)(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.\14\ 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).\15\ 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 emission limitations, compliance
schedules, and other measures that are necessary to make reasonable
progress in such areas. A reasonable progress determination is based on
applying the four factors in CAA section 169A(g)(1) to sources of
visibility impairing pollutants that the state has selected to assess
for controls for the second implementation period. Additionally, as
further explained below, the RHR at 40 CFR 51.308(f)(2)(iv) separately
provides five ``additional factors'' \16\ that states must consider in
developing their long-term strategies.\17\ A state evaluates potential
emission reduction measures for those selected sources and determines
which are necessary to make reasonable progress. Those measures are
then incorporated into the state's long-term strategy. After a state
has developed its long-term strategy, it then establishes RPGs for each
Class I area within its borders by modeling the visibility impacts of
all reasonable progress controls at the end of the second
implementation period, i.e., in 2028, as well as the impacts of other
requirements of the CAA. The RPGs include reasonable progress controls
not only for sources in the state in which the Class I area is located,
but also for sources in other states that contribute to visibility
impairment in that area. The RPGs are then compared to the baseline
visibility conditions and the URP to ensure that progress is being made
towards the statutory goal of preventing any future and remedying any
existing anthropogenic visibility impairment in Class I areas.\18\
There are additional requirements in the rule, including FLM
consultation, that apply to all visibility protection SIPs and SIP
revisions.\19\
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\12\ CAA 169A(b)(2)(B).
\13\ 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.
\14\ 40 CFR 51.308(f), (f)(2).
\15\ 40 CFR 51.308(f)(1).
\16\ The five ``additional factors'' for consideration in
section 51.308(f)(2)(iv) are distinct from the four factors listed
in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states
must consider and apply to sources in determining reasonable
progress.
\17\ 40 CFR 51.308(f)(2).
\18\ 40 CFR 51.308(f)(2)-(3).
\19\ 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 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.\20\ 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.'' \21\ The EPA has explained that the four-factor
analysis is an assessment of potential emission reduction measures
(i.e., control options) for sources; ``use of the terms `compliance'
and `subject to such requirements' in section 169A(g)(1) can be read
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.'' \22\ Thus, for each source it has
selected for four-factor analysis,\23\ a state must consider a
``meaningful set'' of technically feasible control options for reducing
emissions of visibility impairing pollutants.\24\
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\20\ The CAA provides that, ``[i]n determining reasonable
progress there shall be taken into consideration'' the four
statutory factors. CAA 169A(g)(1). However, in addition to four-
factor analyses for selected sources, groups of sources, or source
categories, a state may also consider additional emission reduction
measures for inclusion in its long-term strategy, e.g., from other
newly adopted, on-the-books, or on-the-way rules and measures for
sources not selected for four-factor analysis for the second
planning period.
\21\ CAA 169A(g)(1).
\22\ 82 FR 3078, 3091.
\23\ ``Each source'' or ``particular source'' is used here as
shorthand. While a source-specific analysis is one way of applying
the four factors, neither the statute nor the RHR requires states to
evaluate individual sources. Rather, states have ``the flexibility
to conduct four-factor analyses for specific sources, groups of
sources or even entire source categories, depending on state policy
preferences and the specific circumstances of each state.'' 82 FR
3078, 3088.
\24\ 82 FR 3078, 3088.
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The EPA has also explained that, in addition to the four statutory
factors, states have flexibility under the CAA and RHR to reasonably
consider visibility benefits as an additional factor alongside the four
statutory factors.\25\ Ultimately, while states have discretion to
reasonably weigh the factors and to determine what level of control is
needed, section 51.308(f)(2)(i) provides that a state ``must include in
its

[[Page 7207]]

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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\25\ See, e.g., Responses to Comments on Protection of
Visibility: Amendments to Requirements for State Plans; Proposed
Rule (81 FR 26942, May 4, 2016), Docket Number EPA-HQ-OAR-2015-0531,
U.S. Environmental Protection Agency at 186.
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As explained above, section 51.308(f)(2)(i) requires states to
determine the emission reduction measures for sources that are
necessary to make reasonable progress by considering the four factors.
Pursuant to section 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 section 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, section 51.308(f)(2)(iii) plays an important
function in requiring a state to document the technical basis for its
decision making so that the public and the EPA can comprehend and
evaluate the information and analysis the state relied upon to
determine what emission reduction measures must be in place to make
reasonable progress. The technical documentation must include the
modeling, monitoring, cost, engineering, and emissions information on
which the state relied to determine the measures necessary to make
reasonable progress. Additionally, the RHR at 40 CFR 51.3108(f)(2)(iv)
separately provides five ``additional factors'' \26\ that states must
consider in developing their long-term strategies: (1) Emission
reductions due to ongoing air pollution control programs, including
measures to address reasonably attributable visibility impairment; (2)
measures to reduce the impacts of construction activities; (3) source
retirement and replacement schedules; (4) basic smoke management
practices for prescribed fire used for agricultural and wildland
vegetation management purposes and smoke management programs; and (5)
the anticipated net effect on visibility due to projected changes in
point, area, and mobile source emissions over the period addressed by
the long-term strategy.
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\26\ The five ``additional factors'' for consideration in
section 51.308(f)(2)(iv) are distinct from the four factors listed
in CAA section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states
must consider and apply to sources in determining reasonable
progress.
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Because the air pollution that causes regional haze crosses state
boundaries, section 51.308(f)(2)(ii) requires a state to consult with
other states that also have emissions that are reasonably anticipated
to contribute to visibility impairment in a given Class I area. If a
state, pursuant to consultation, agrees that certain measures (e.g., a
certain emission limitation) are necessary to make reasonable progress
at a Class I area, it must include those measures in its SIP.\27\
Additionally, the RHR requires that states that contribute to
visibility impairment at the same Class I area consider the emission
reduction measures the other contributing states have identified as
being necessary to make reasonable progress for their own sources.\28\
If a state has been asked to consider or adopt certain emission
reduction measures, but ultimately determines those measures are not
necessary to make reasonable progress, that state must document in its
SIP the actions taken to resolve the disagreement.\29\ Under all
circumstances, a state must document in its SIP submission all
substantive consultations with other contributing states.\30\
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\27\ 40 CFR 51.308(f)(2)(ii)(A).
\28\ 40 CFR 51.308(f)(2)(ii)(B).
\29\ 40 CFR 51.308(f)(2)(ii)(C).
\30\ 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.'' \31\
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\31\ 82 FR 3078, 3091.
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For the second implementation period, the RPGs are set for 2028.
RPGs are not enforceable targets.\32\ While states are not legally
obligated to achieve the visibility conditions described in their RPGs,
section 51.308(f)(3)(i) requires that ``[t]he long-term strategy and
the reasonable progress goals must provide for an improvement in
visibility for the most impaired days since the baseline period and
ensure no degradation in visibility for the clearest days since the
baseline period.'' RPGs may also serve as a metric for assessing the
amount of progress a state is making towards the national visibility
goal. To support this approach, the RHR requires states with Class I
areas to compare the 2028 RPG for the most impaired days to the
corresponding point on the URP line (representing visibility conditions
in 2028 if visibility were to improve at a linear rate from conditions
in the baseline period of 2000-2004 to natural visibility conditions in
2064). If the most impaired days RPG in 2028 is above the URP (i.e., if
visibility conditions are improving more slowly than the rate described
by the URP), each state that contributes to visibility impairment in
the Class I area must demonstrate, based on the four-factor analysis
required under 40 CFR 51.308(f)(2)(i), that no additional emission
reduction measures would be reasonable to include in its long-term
strategy.\33\ 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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\32\ 40 CFR 51.308(f)(3)(iii).
\33\ 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 subsection apply either to states with Class I
areas within their borders, states with no Class I areas but that are
reasonably anticipated to cause or contribute to visibility impairment
in any Class I area, or both. 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.\34\
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\34\ 40 CFR 51.308(f)(6), (f)(6)(i), (f)(6)(iv).
---------------------------------------------------------------------------

All states' SIPs must provide for procedures by which monitoring
data and other information are used to determine the contribution of
emissions from within the state to regional haze visibility impairment
in affected Class I areas, as well as a statewide inventory documenting
such emissions.\35\ All states' SIPs must also provide for any other
elements, including reporting, recordkeeping, and other measures, that

[[Page 7208]]

are necessary for states to assess and report on visibility.\36\
---------------------------------------------------------------------------

\35\ 40 CFR 51.308(f)(6)(ii), (iii).
\36\ 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.\37\ To this end, every state's SIP revision for the second
implementation period is required to assess changes in visibility
conditions and describe the status of implementation of all measures
included in the state's long-term strategy, including BART and
reasonable progress emission reduction measures from the first
implementation period, and the resulting emissions reductions.\38\
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\37\ 81 FR 26942, 26950 (May 4, 2016); 82 FR 3078, 3119.
\38\ 40 CFR 51.308(g)(1) and (2).
---------------------------------------------------------------------------

E. Requirements for State and Federal Land Manager Coordination

CAA section 169A(d) requires that before a state holds a public
hearing on a proposed regional haze SIP revision, it must consult with
the appropriate FLM or FLMs; pursuant to that consultation, the state
must include a summary of the FLMs' conclusions and recommendations in
the notice to the public. Consistent with this statutory requirement,
the RHR also requires that states ``provide the [FLM] with an
opportunity for consultation, in person and at a point early enough in
the State's policy analyses of its long-term strategy emission
reduction obligation so that information and recommendations provided
by the [FLM] can meaningfully inform the State's decisions on the long-
term strategy.'' \39\ For the EPA to evaluate whether FLM consultation
meeting the requirements of the RHR has occurred, the SIP submission
should include documentation of the timing and content of such
consultation. The SIP revision submitted to the EPA must also describe
how the state addressed any comments provided by the FLMs.\40\ 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.\41\
---------------------------------------------------------------------------

\39\ 40 CFR 51.308(i)(2).
\40\ 40 CFR 51.308(i)(3).
\41\ 40 CFR 51.308(i)(4).
---------------------------------------------------------------------------

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

A. Background on the EPA's FIP for Hawaii in the First Implementation
Period

The requirements for regional haze SIP revisions for the first
implementation period are contained in 40 CFR 51.308(d) and (e).\42\ On
October 9, 2012, the EPA issued a Federal Implementation Plan (FIP) to
address these requirements for the State of Hawaii.\43\ The EPA worked
closely with the State in developing the FIP, which established an
emissions cap of 3,550 tons of SO<INF>2</INF> per year from three
specific oil-fired, electric utility boilers on the island of Hawaii
beginning in 2018 to ensure that reasonable progress was made during
the first planning period. Pursuant to 40 CFR 51.308(g), Hawaii was
also responsible for submitting a five-year progress report as a SIP
revision for the first implementation period, which it did on October
20, 2017.\44\ The EPA approved the progress report into the Hawaii SIP
on August 12, 2019.\45\
---------------------------------------------------------------------------

\42\ 40 CFR 51.308(b).
\43\ 77 FR 61478 (October 9, 2012). As the State of Hawaii
failed to submit a regional haze SIP revision for the first
implementation period, the EPA was required under the CAA to
promulgate a FIP to fill this gap.
\44\ Letter dated October 20, 2017, from Virginia Pressler,
Director of Health, Hawaii Department of Health, to Alexis Strauss,
Acting Regional Administrator, EPA Region IX.
\45\ 84 FR 39754 (August 12, 2019).
---------------------------------------------------------------------------

B. Hawaii's Second Implementation Period SIP Submission

In accordance with CAA sections 169A and the RHR at 40 CFR
51.308(f), on August 2, 2024, HDOH submitted the 2024 Hawaii Regional
Haze Plan to address its regional haze obligations for the second
implementation period, which run through 2028. The State made its 2024
Hawaii Regional Haze Plan available for public comment for 30 days on
November 27, 2023. No written comments were received by the closing
date of the public comment period. Additionally, the State held a
public hearing on April 19, 2024. HDOH received and responded to public
oral testimonies and included the comments and responses to those
comments in Appendix X to the 2024 Hawaii Regional Haze Plan.
The following sections describe the 2024 Hawaii Regional Haze Plan
and provide the EPA's evaluation of Hawaii's submission against the
requirements of the CAA and RHR for the second implementation period of
the regional haze program.

C. Identification of Class I Areas

Section 169A(b)(2) of the CAA requires each state in which any
Class I area is located or ``the emissions from which may reasonably be
anticipated to cause or contribute to any impairment of visibility'' in
a Class I area to have a plan for making reasonable progress toward the
national visibility goal. The RHR implements this statutory requirement
at 40 CFR 51.308(f), which provides that each state's plan ``must
address regional haze in each mandatory Class I Federal area located
within the State and in each mandatory Class I Federal area located
outside the State that may be affected by emissions from within the
State,'' and (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,'' \46\ 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.
---------------------------------------------------------------------------

\46\ 64 FR 35714, 35721.
---------------------------------------------------------------------------

Hawaii has two Class I Federal areas within its borders: the Hawaii
Volcanoes National Park and the Haleakala National Park. For the second
implementation period, WRAP and the State performed technical analyses
to help assess source and state-level contribution to visibility
impairment and the need for interstate consultation. As detailed in
Chapter 5 of the 2024 Hawaii Regional Haze Plan, HDOH used a Q/d
screening tool developed from work led by WRAP and Ramboll as a
surrogate for the visibility impact of sources on the Class I Federal
areas within the state.\47\ Based on this initial

[[Page 7209]]

screening, HDOH identified seven facilities on the islands of Oahu,
Maui, and Hawaii with a Q/d greater than or equal to 10. HDOH requested
that the owner of each identified facility develop and submit a four-
factor analysis to HDOH. Following this initial Q/d screening, WRAP
provided a weighted emissions potential/area of influence (WEP/AOI)
analysis to further screen facilities. In addition to emissions and
distance, the WEP/AOI analysis accounted for meteorological data such
as wind patterns and the specific light extinction contribution of
nitrate and sulfate particulates. This WEP/AOI analysis showed that the
sources on the island of Oahu that did not rank high (less than one
percent contributors for nitrate and sulfate pollution from all point
sources examined) \48\ in their potential to affect visibility in the
Class I areas. As a result, HDOH excluded all the examined sources on
Oahu from requiring a four-factor analysis. Ultimately, based on the
WEP/AOI analysis, HDOH determined that the sources required to conduct
four-factor analysis were only the electric plants on the islands of
Hawaii and Maui and the Mauna Loa Macadamia Nut Corporation Plant on
the island of Hawaii.\49\
---------------------------------------------------------------------------

\47\ ``Q/d'' is emissions (Q) in tons per year (tpy), typically
of one or a combination of visibility-impairing pollutants, divided
by distance to a class I area (d) in kilometers. The resulting ratio
is commonly used as a metric to assess a source's potential
visibility impacts on a particular class I area.
\48\ 2024 Hawaii Regional Haze Plan, Chapter 5.10.
\49\ Id. Chapter 5.0.
---------------------------------------------------------------------------

With regard to Hawaii's contribution to visibility impairment at
out-of-state Class I areas, the 2024 Hawaii Regional Haze Plan states
that that emissions from within the State are not reasonably expected
to affect Class I areas in other states because the nearest states to
Hawaii with Class I areas, Alaska and California, are over 2,000 miles
away. The State's reasoning is consistent with the EPA's reasoning for
including Hawaii (as well as Alaska and the Virgin Islands) in the RHR,
which was based on the potential of emissions within the State to
contribute to visibility impairment at Class I areas within the State,
rather than at any out-of-State areas.\50\ Other remote territories,
such as Puerto Rico, were not included in the RHR ``because their
distance from any Class I area significantly exceed the distance that
their emissions could be expected to be transported in order to
contribute to visibility impairment in any Class I area.'' \51\ As
discussed in further detail below, the EPA is proposing to find that
Hawaii has submitted a regional haze plan that fails to meet the
requirements of 40 CFR 51.308(f)(2) related to the development of a
long-term strategy. However, this determination is not based on any
failure of the state to identify Class I areas that may be affected by
emissions from the state.
---------------------------------------------------------------------------

\50\ 64 FR 35714, 35720. See also 77 FR 31692, 31713 (May 29,
2012) (explaining the same in the context of the EPA's proposed FIP
for Hawaii in the second planning period).
\51\ Id.
---------------------------------------------------------------------------

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.\52\
---------------------------------------------------------------------------

\52\ 40 CFR 51.308(f)(1)(vi)(B).
---------------------------------------------------------------------------

In the 2024 Hawaii Regional Haze Plan, HDOH used visibility data
from IMPROVE monitoring sites for baseline, current, and natural
visibility conditions. The HAVO1 IMPROVE monitor started operation at
the Hawaii Volcanoes National Park in 1998, and visibility monitoring
at the Haleakala National Park visibility was tracked by both the HALE1
monitor from 1990 until 2012 and the HACR1 monitor from 2007 onward.
On August 5, 2021 the EPA issued the ``Recommendations for the
HALE1-HACR1 IMPROVE Monitoring Site Combination and Volcano Adjustment
for Sites Representing Hawaii Class I Areas for the Regional Haze
Rule'' (``2021 Hawaii Visibility Data Adjustment Memo'') \53\ to build
upon the December 2018 ``Technical Guidance on Tracking Visibility
Progress for the Second Implementation Period of the Regional Haze
Program,'' \54\ and the June 2020 ``Recommendation for the Use of
Patched and Substituted Data and Clarification of Data Completeness for
Tracking Visibility Progress for the Second Implementation Period of
the Regional Haze Program'' and associated Technical Addendum.\55\ The
purpose of the 2021 Hawaii Visibility Data Adjustment Memo was to
combine the visibility data for the HALE1 and HACR1 monitoring sites
representing the Haleakala National Park into a single continuous data
set, and to attempt to account for episodic volcanic events affecting
both Hawaii Class I areas. The combination of visibility data for the
HALE1 and HACR1 monitoring sites was necessary because the default EPA
methodology for determining the 20 percent most-impaired days for the
2000-2004 baseline period relies on a complete visibility data set for
2000-2014, whereas the individual sites each cover only a portion of
that period.
---------------------------------------------------------------------------

\53\ EPA Office of Air Quality Planning and Standards,
``Recommendations for the HALE1-HACR1 IMPROVE Monitoring Site
Combination and Volcano Adjustment for Sites Representing Hawaii
Class I Areas for the Regional Haze Rule,'' available at <a href="https://www.epa.gov/system/files/documents/2021-08/white_paper_for_regional_haze_hi_volcano_adjust_final.pdf">https://www.epa.gov/system/files/documents/2021-08/white_paper_for_regional_haze_hi_volcano_adjust_final.pdf</a> (August 5,
2021).
\54\ EPA Office of Air Quality Planning and Standards,
``Technical Guidance on Tracking Visibility Progress for the Second
Implementation Period of the Regional Haze Program,'' available at
<a href="https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional">https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional</a> (December
20, 2018).
\55\ EPA Office of Air Quality Planning and Standards,
``Recommendation for the Use of Patched and Substituted Data and
Clarification of Data Completeness for Tracking Visibility Progress
for the Second Implementation Period of the Regional Haze Program,''
available at <a href="https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program">https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program</a>
(June 3, 2020).
---------------------------------------------------------------------------

The 2021 Hawaii Visibility Data Adjustment Memo also provides an
approach for determining the 20 percent most impaired days for the
baseline, most recent, and natural visibility conditions for both
Hawaiian Class I Areas, and was intended to account for episodic
volcanic events. This approach is similar to the approach that the
EPA's 2018 Visibility Tracking Guidance recommended for estimating
episodic carbon from wildfires, and episodic fine soil and coarse
matter from dust storms, but also applied to sulfate. The sulfate
adjustment involves first identifying the 95th-percentile 24-hour
ammonium sulfate extinction value for each year between 2000 and 2014
and selecting the year with the lowest value for each IMPROVE site.
This value then serves as a threshold above which daily ammonium
sulfate extinction is considered to be episodic natural extinction for
the impairment calculations The remainder, non-episodic or routine
extinction, is then split into routine natural and anthropogenic
portions, with the help of

[[Page 7210]]

established long-term averages for routine natural extinction.\56\ The
anthropogenic part is used to select the most impaired days. Once the
days are selected, total haze deciview (dv) is computed (including
anthropogenic, routine natural, and episodic natural portions) for
computing 2014-2018 baseline visibility and for projecting to the 2028
RPGs. Even with these adjustments, ammonium sulfate extinction remains
relatively high for both sites and the dominant component of the
overall extinction on the 20 percent most-impaired days. Given the
relatively lower anthropogenic SO<INF>2</INF> emissions inventory for
the state and the low sulfate concentrations predicted for these sites
in the EPA's Regional Haze modeling for Hawaii,\57\ it appears that,
even with the additional adjustments, the 20 percent most-impaired days
include a substantial contribution from ammonium sulfate resulting from
volcanic emissions. This result likely emerged because the adjustment
method was a variant of EPA's 2018 Visibility Tracking Guidance
approach, which was intended to screen out episodic wildfire and dust
storm events rather than ongoing events with emissions over many years.
Because the Kilauea Volcano had continuous eruption events between 1983
and 2018,\58\ volcanic emissions contribute to sulfate extinction in
every year, and often on days below the 95th percentile. Therefore,
days with relatively high volcanic sulfate contributions remain even
after the adjustment procedure. Additionally, volcanic emissions do not
divide as neatly into discrete episodes as wildfires and dust storms
typically do, so the days remaining after the adjustment procedure do
not necessarily have both relatively large anthropogenic impairment and
a relatively low natural contribution. Accordingly, the impacts of the
volcano could not be fully screened out using this methodology.
Furthermore, to date, no alternative methodology has been developed
that is able to fully screen out the volcanic impacts and thus isolate
the visibility impairment caused by anthropogenic air pollution.
Therefore, the levels of baseline and current total haze on the 20
percent most-impaired days at both of Hawaii's Class I (and
particularly Hawaii Volcanoes) include the effects of both
anthropogenic and volcanic SO<INF>2</INF>/sulfate emissions. Changes in
visibility over the years would then mostly reflect year-to-year
variation in the overwhelming natural volcanic contribution, rather
than increases or decreases in the much smaller anthropogenic
emissions.\59\ This would affect the comparison of current to baseline
conditions, the calculation of the URP, and the assessment of whether
the RPG is above or below the URP.
---------------------------------------------------------------------------

\56\ EPA's 2018 Visibility Tracking Guidance, p.6, the ``NC-II''
estimates of natural visibility conditions. The starting point for
those estimates was a set of concentrations for the eastern and for
the western portions of the continental US, and do not include any
volcano effects.
\57\ Technical Support Document for EPA's Updated 2028 Regional
Haze Modeling for Hawaii, Virgin Islands, and Alaska. EPA-454/R-21-
007, August 2021, pp. B-6 and B-7.
\58\ 2024 Hawaii Regional Haze Plan, p.1.
\59\ The Statewide Emissions Inventory tables in section 4.1 of
the 2024 Hawaii Regional Haze Plan show SO<INF>2</INF> emissions
estimates for years ranging from 2005 to 2028 where volcanic
emissions are one or even two orders of magnitude greater than that
the SO<INF>2</INF> emissions estimates attributed to point sources.
---------------------------------------------------------------------------

Using updated dv values from the 2021 Hawaii Visibility Data Memo,
HDOH provided estimates of baseline, current, and natural visibility
conditions, as well as the progress to date, differences between
current visibility conditions and natural visibility conditions and the
URP for each of the state's Class I areas in Chapter 3 of the 2024
Hawaii Regional Haze Plan. A summary of Hawaii's visibility conditions
and URPs is also presented in Table 1 of the Plan. Hawaii did not
adjust the URPs to account for international anthropogenic impacts nor
for the impacts of wildland prescribed fires.
The Hawaii Volcanoes National Park 2000-2004 baseline visibility
conditions are 4.06 dv on the 20 percent clearest days and 15.60 dv on
the 20 percent most impaired days.\60\ Natural visibility conditions,
as estimated by the EPA in the 2021 Hawaii Visibility Data Adjustment
Memo, are 2.20 dv on the 20 percent clearest days and 6.62 dv on the 20
percent most impaired days for Hawaii Volcanoes National Park. The
current visibility conditions, which were based on 2015-2019 monitoring
data, were 3.50 dv on the clearest days and 16.31 dv on the most
impaired days, which were 1.30 dv and 9.69 dv greater than the natural
conditions on the respective sets of days. The progress to date,
subtracting current conditions from baseline conditions, yields a 0.56
dv improvement for the 20 percent clearest days and -0.71 dv
deterioration for the 20 percent most impaired days. HDOH calculated an
annual URP of 0.15 dv per year needed to reach natural visibility on
the 20 percent most impaired days by 2064. HDOH also indicates that the
visibility improvement needed to maintain the URP from the baseline to
2028 is 3.60 dv. As noted above, the estimate of natural conditions
recommended in the EPA's 2018 Visibility Tracking Guidance does not
include volcanic emissions, so the estimate is very likely too low. The
estimated URP would then be too large, i.e., the glidepath from
baseline conditions to natural conditions declines more steeply than it
should.
---------------------------------------------------------------------------

\60\ Tables 3.0-4 and 3.1-2 in the 2024 Hawaii Regional Haze
Plan depict the baseline, natural, and current most impaired day and
clearest day visibility in dv, adjusted for volcanic episodic
activity, for the HAVO1 monitoring site. Table 3.2-2 depicts the
2028 and 2064 URP for the 20 percent most impaired days.
---------------------------------------------------------------------------

The Haleakala National Park has 2000-2004 baseline visibility
conditions of 2.18 dv on the 20 percent clearest days and 7.84 dv on
the 20 percent most impaired days.\61\ Natural visibility conditions,
as estimated by the EPA in the 2021 Hawaii Visibility Data Adjustment
Memo, are -0.12 dv on the 20 percent clearest days and 4.22 dv on the
20 percent most impaired days for Hawaii Volcanoes National Park. The
current visibility conditions, which are based on 2015-2019 monitoring
data, were 0.48 dv on the clearest days and 7.27 dv on the most
impaired days, which are 0.60 dv and 3.05 dv greater than the natural
conditions on the respective sets of days. The progress to date,
subtracting current conditions from baseline conditions, yields a 1.70
dv improvement for the 20 percent clearest days and 0.57 dv improvement
for the 20 percent most impaired days. HDOH calculated an annual URP of
0.06 dv per year needed to reach natural visibility on the 20 percent
most impaired days by 2064. HDOH also indicates that the visibility
improvement needed to maintain the URP from the baseline to 2028 is
1.44 dv.
---------------------------------------------------------------------------

\61\ Tables 3.0-4 and 3.1-2 in the 2024 Hawaii Regional Haze
Plan depicts the baseline, natural, and current most impaired day
and clearest day visibility in dv, adjusted for volcanic episodic
activity, for the HALE1 monitoring site. Table 3.2-2 depicts the
2028 and 2064 URP for the 20 percent most impaired days.

[[Page 7211]]

Table 1--Visibility Conditions and Uniform Rate of Progress, in Deciviews (dv)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
20% Clearest days 20% Most-impaired days Maintain URP
----------------------------------------------------------------------------------------------------------------------------------
Class I area total dv total dv
Baseline Current Natural Difference Baseline Current Natural Difference dv per year (baseline (baseline
to 2019) to 2028)
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Hawaii Volcanoes National Park............................... 4.06 3.50 2.20 1.30 15.60 16.31 6.62 9.69 0.150 2.25 3.60
Haleakala National Park...................................... 2.18 0.48 -0.12 0.60 7.84 7.27 4.22 3.05 0.06 0.9 1.44
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2024 Hawaii Regional Haze Plan Tables 3.0-1 and 3.0-2.

The EPA is proposing to find that the 2024 Hawaii 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; differences between current visibility conditions and
natural visibility conditions; and the URPs for the second
implementation period. However, as previously noted, due to limitations
in the current methodologies for screening out the effects of volcanic
emissions, the estimated levels of baseline and current visibility
conditions at both of Hawaii's Class I areas are not able to adequately
identify anthropogenic emissions impacts and continue to include the
impact of volcanic emissions.

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.\62\ 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 section
51.308(f)(2)(iv). As part of its reasonable progress determinations,
the state must describe the criteria used to determine which sources or
group of sources were evaluated (i.e., subjected to four-factor
analysis) for the second implementation period and how the four factors
were taken into consideration in selecting the emission reduction
measures for inclusion in the long-term strategy.\63\
---------------------------------------------------------------------------

\62\ CAA 169A(b)(2)(B).
\63\ 40 CFR 51.308(f)(2)(iii).
---------------------------------------------------------------------------

The requirements of section 51.308(f)(2)(ii) provide that states
must consult with other states that have emissions that are reasonably
anticipated to contribute to visibility impairment in a Class I area to
develop and coordinate emission management strategies containing the
emission reductions measures that are necessary to make reasonable
progress. Section 51.308(f)(2)(ii)(A) and (B) require states to
consider the emission reduction measures identified by other states as
necessary for reasonable progress and to include agreed upon measures
in their SIPs. Section 51.308(f)(2)(ii)(C) speaks to what happens if
states cannot agree on what measures are necessary to make reasonable
progress.
Section 51.308(f)(2)(iii) requires that the emissions information
considered to determine measures 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 following sections summarize how the 2024 Hawaii Regional Haze
Plan addresses the requirements of 40 CFR 51.308(f)(2) long-term
strategy for the second planning period.
1. Determination of Which Pollutants To Consider
To evaluate which pollutants had the greatest impact at Hawaii's
Class I areas, HDOH examined the pollutant composition that resulted in
the light extinction measured at in-state IMPROVE sites from 2014-2018
and compared the relative impact of the different pollutants on
visibility conditions over that time.\64\ HDOH noted that, on both the
most impaired and the clearest days, ammonium sulfate is by far the
primary contributor to visibility impairment at the Class I areas in
the state. Measured on the most impaired days, it contributes 75
percent and 87 percent of the light extinction measured at the
Haleakala National Park and Hawaii Volcanoes National Park,
respectively. SO<INF>2</INF> emissions are a necessary precursor to the
formation of sulfate species, and thus sources of SO<INF>2</INF> are
considered when evaluating the potential source of visibility impairing
sulfate pollution. In Hawaii, the Kilauea Volcano located within the
Hawaii Volcanoes National Park is the greatest natural source of non-
anthropogenic SO<INF>2</INF> emissions, while point sources that
combust fuel oil are the greatest anthropogenic emitters of
SO<INF>2</INF>. Most of these anthropogenic point sources are power
plants located on the islands of Hawaii, Oahu, and Maui. In
considerably less magnitude, ammonium nitrate was identified to
contribute 5.4 percent and 1.4 percent of the light extinction on the
most impaired days at the Haleakala National Park and the Hawaii
Volcanoes National Park, respectively. Similar to SO<INF>2</INF> with
sulfates, NO<INF>X</INF> emissions are a precursor to the formation of
nitrate species. Point sources that combust fuel oil are also the major
anthropogenic emitters of NO<INF>X</INF>. Coarse mass is reported by
the IMPROVE network as the difference between particulate matter with
an aerodynamic diameter of 10 microns (PM<INF>10</INF>) and
PM<INF>2.5,</INF> and was identified as contributing to 6 percent and
5.8 percent of the light extinction on the most impaired days for
Haleakala National Park and Hawaii Volcanoes National Park,
respectively. Anthropogenic sources of coarse mass include fugitive
dust from unpaved roads, aggregate processing, and construction
activities. Because coarse mass is not commonly included in emissions
inventories, states generally use PM<INF>10</INF> as a surrogate for
coarse mass. Finally, organic mass was identified as contributing 4.9
percent and 3.6 percent to the most impaired days at the Haleakala
National Park and the Hawaii Volcanoes National Park, respectively.
Sources of organic mass include, agricultural burning, wildfires, oil
combustion, and international transport. Based on this analysis, HDOH
selected SO<INF>2</INF>, NO<INF>X</INF>, and particulate matter as the
pollutants of primary concern for source screening during the second
planning period in order to maximize the possible benefits of potential
control measures.
---------------------------------------------------------------------------

\64\ 2024 Hawaii Regional Haze Plan, pp. 17-25.
---------------------------------------------------------------------------

2. Source Selection
Hawaii used the Q/d method to identify sources that are reasonably

[[Page 7212]]

expected to contribute to visibility impairment at any Class I area.
Specifically, HDOH used a Q/d threshold of 10 (combined NO<INF>X</INF>,
SO<INF>2,</INF> and PM<INF>10</INF> emissions) based on the 2014
National Emissions Inventory Version 2 to measure sources' potential
contributions to visibility impairment for control evaluation.\65\ This
screening methodology identified ten point sources. However, HDOH
screened out three of these sources from further analysis for the
following reasons: the AES Hawaii LLC Cogeneration Plant was
permanently shut down as of August 2022; and the Honolulu International
Airport and the Kahului Airport on the island of Maui are not under the
State's jurisdiction to develop emissions controls, since the vast
majority of their emissions are from aircraft.\66\ The Q/d analysis
eventually resulted in HDOH's preliminary selection of seven point
sources for four-factor analysis, shown in Table 2.
---------------------------------------------------------------------------

\65\ For facilities with multiple emissions units/processes, the
facility location was based on the emission unit/process with the
highest Q.
\66\ 2024 Hawaii Regional Haze Plan, pp. 56-58.

Table 2--Point Sources Selected for Four-Factor Analysis Using Q/d Analysis
----------------------------------------------------------------------------------------------------------------
Point source Location Q (TPY) d (km) Q/d Class I area
----------------------------------------------------------------------------------------------------------------
Kalaeloa Partners, L.P. Plant.... Oahu............ 6,216 201.9 30.91 1.) Haleakala NP.
Hawaiian Electric Company--Kahe Oahu............ 13,968 206.11 67.77 1.) Haleakala NP.
Power Plant. 328.98 42.46 2.) Hawaii Volcanoes
NP.
Hawaiian Electric Company--Waiau Oahu............ 5,828 190.89 30.53 1.) Haleakala NP.
Power Plant. 318.39 18.31 2.) Hawaii Volcanoes
NP.
Hawaii Electric Light Company-- Hawaii.......... 2,519 147.01 17.13 1.) Haleakala NP.
Kanoelehua-Hill Power Plant. 25.69 98.07 2.) Hawaii Volcanoes
NP.
Hawaii Electric Light Company-- Hawaii.......... 623 23.01 27.09 1.) Haleakala NP.
Puna Power Plant.
Maui Electric Company--Kahului Maui............ 2,177 26.49 82.20 1.) Haleakala NP.
Power Plant. 176.82 12.31 2.) Hawaii Volcanoes
NP.
Maui Electric Company--Maalaea Maui............ 3,508 25.52 110.18 1.) Haleakala NP.
Generating Station. 169.61 16.57 2.) Hawaii Volcanoes
NP.
----------------------------------------------------------------------------------------------------------------
Source: 2024 Hawaii Regional Haze Plan, Table 5.7-1.

HDOH further refined this list of seven point sources considered
for four-factor analysis using the results of a WEP/AOI analysis,
conducted by WRAP.\67\ The WEP/AOI analysis showed that point sources
near the Hawaii Class I areas had the greatest potential to contribute
to visibility impairment on the most impaired days from 2014 to 2018,
rather than those on separate islands. Therefore, while initially
selected for four-factor analysis using the Q/d ranking, the Kalealoa
Partners L.P., Kahe, and Waiau Power Plants on the island of Oahu did
not meet the WEP/AOI analysis criteria for the potential to contribute
to visibility impairment at the Class I areas on the islands of Maui
and Hawaii. Therefore, these sources were excluded from consideration
under the four-statutory factors during the second planning period.
However, the WEP/AOI analysis also identified that the Mauna Loa
Macadamia Nut Plant on the island of Hawaii and the HC&D Camp 10 Quarry
on Maui were high ranking among sources with the greatest potential to
contribute to visibility impairment from ammonium nitrate emissions at
the Class I areas. The Mauna Loa Macadamia Nut Plant was selected for
four-factor analysis. Although the facility ranked high, the WEP/AOI
model predicted the HC&D Camp 10 Quarry accounted for approximately one
percent of the total ammonium nitrate contribution at Haleakala
National Park, and considering the other screened-in sources selected
for control analysis accounted for approximately 98% of the total
ammonium nitrate contribution, HDOH excluded the HC&D Camp 10 Quarry
from further evaluation. Therefore, between the Q/d and WEP/AOI
analysis, five point sources were selected for four-factor analysis:
---------------------------------------------------------------------------

\67\ Details of the WEP/AOI analysis are summarized in Section
5.10 of the 2024 Hawaii Regional Haze Plan.

1. Hawaiian Electric Light Company--Kanoelehua-Hill Power Plant
2. Hawaiian Electric Light Company--Puna Power Plant
3. Maui Electric Light Company--Kahului Power Plant
4. Maui Electric Light Company--Maalaea Power Plant
5. Mauna Loa Macadamia Nut Corporation Plant
3. Four-Factor Analyses
The State evaluated potential control measures based on four-factor
analyses provided by the facilities identified in the screening
process. When preparing their four-factor analyses, selected facilities
considered potential emissions controls such as device retrofits, fuel
switches/mixing with lower SO<INF>2</INF>. NO<INF>X</INF>, and
PM<INF>10</INF> emissions, operating restriction on hours and fuel
input, emission limits, and unit shutdowns.
a. Cost of Compliance
To determine cost of compliance, HDOH followed the methodologies in
the EPA's Air Pollution Control Cost Manual.\68\ The State adjusted the
control costs estimates provided by the facilities by applying an 8.25
percent prime interest rate and adjusting for cost/total combined tons
of pollutant removed, estimated equipment life remaining, retrofit
factor, and the additional construction costs associated with Hawaii
and Maui Islands. The resulting cost effectiveness values of available
controls for the Kanoelehua-Hill Power Plant, the Puna Power Plant, the
Kahului Power Plant, the Maalaea Power Plant, and the Mauna Loa
Macadamia Nut Corporation Plant, are summarized in Tables 3-7 of this
document.
---------------------------------------------------------------------------

\68\ Chapters of the EPA Air Pollution Control Cost Manual are
hosted at the following website: <a href="https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution">https://www.epa.gov/economic-and-cost-analysis-air-pollution-regulations/cost-reports-and-guidance-air-pollution</a>.
---------------------------------------------------------------------------

HDOH set a cost effectiveness threshold of $6,800/ton of pollutant
removed. HDOH considered controls with cost-effectiveness values at,
below, or slightly above this threshold to be cost-effective for Hawaii
emissions sources evaluated under the four-factor analysis in the
regional haze second planning period.

[[Page 7213]]

Table 3--Four-Factor Analysis for the Kanoelehua-Hill Power Plant
----------------------------------------------------------------------------------------------------------------
Control measure & cost
Unit Description Primary fuel per ton
----------------------------------------------------------------------------------------------------------------
Hill 5............................... 14 MW Boiler........... Fuel Oil No. 6 with Enforceable shutdown by
2.0% maximum sulfur December 31, 2028.
content.
Hill 6............................... 23 MW Boiler........... Fuel Oil No. 6 with
2.0% maximum sulfur
content.
CT-1................................. 11.6 MW Combustion Fuel Oil No. 6 with Operated on a limited
Turbine. 2.0% maximum sulfur basis in 2017, and
content. therefore a four-
factor analysis was
not conducted for the
unit. Another round of
screening for four-
factor analysis will
be revisited in the
third regional haze
planning period.
D-11................................. 2.75 MW DEG............ Ultra-low sulfur diesel Operated on a limited
D-15................................. 2.75 MW DEG............ (ULSD). basis in 2017, and
D-16................................. 2.75 MW DEG............ ULSD................... therefore a four-
D-17................................. 2.75 MW DEG............ ULSD................... factor analysis was
ULSD................... not conducted for the
unit. Another round of
screening for four-
factor analysis will
be revisited in the
third regional haze
planning period.
----------------------------------------------------------------------------------------------------------------

Table 4--Four-Factor Analysis for the Puna Power Plant
----------------------------------------------------------------------------------------------------------------
Control measure & cost per
Unit Description Primary fuel ton
----------------------------------------------------------------------------------------------------------------
Boiler............................. 15.5 MW Boiler........ Fuel Oil No. 6 with <bullet> Fuel switch to
2.0% maximum sulfur ultra-low-sulfur diesel
content. (ULSD) with 0.0015% sulfur
content--$6,014/ton of
SO2, NOX, and PM10.
<bullet> Boiler Combustion
Controls (Low NOX burner
(LNB) with overfire air/
flue gas recirculation)--
$19,109/ton of NOX.
<bullet> Selective
catalytic reduction (SCR)
for Boiler--$43,254/ton of
NOX.
<bullet> SCR + Combustion
Control for Boiler--
$39,793/ton of NOX.
<bullet> Selective non-
catalytic reduction (SNCR)
for Boiler--$36,345/ton of
NOX.
<bullet> SNCR + Combustion
Controls--$44,417/ton of
NOX.
<bullet> Wet Scrubber for
Boiler--$39,352/ton of
PM10.
<bullet> Wet Electrostatic
Precipitator (ESP) for
Boiler--$583,295/ton of
PM10.
CT-3............................... 23 MW Boiler.......... Fuel Oil No. 4 with <bullet> CT-3 was
0.4% maximum sulfur considered a limited use
content. unit based on its
operation in 2017, and
therefore a four-factor
analysis was not conducted
for this unit.
----------------------------------------------------------------------------------------------------------------

Table 5--Four-Factor Analysis for the Kahului Power Plant
----------------------------------------------------------------------------------------------------------------
Control measure & cost per
Unit Description Primary fuel ton
----------------------------------------------------------------------------------------------------------------
K-1................................ 5.0 MW Boiler......... Fuel Oil No. 6 with <bullet> Boilers K-1, K-2,
...................... 2.0% maximum sulfur K-3, K-4 are required to
K-2................................ 5.0 MW Boiler......... content. shut down by December 31,
Fuel Oil No. 6 with 2028, and is therefore not
2.0% maximum sulfur subject to a four-factor
content. analysis.
K-3................................ 11.5 MW Boiler........ Fuel Oil No. 6 with
2.0% maximum sulfur
content.
K-4................................ 11.5 MW Boiler........ Fuel Oil No. 6 with
2.0% maximum sulfur
content.
----------------------------------------------------------------------------------------------------------------

Table 6--Four-Factor Analysis for the Maalaea Power Plant
----------------------------------------------------------------------------------------------------------------
Control measure & cost
Unit Description Primary fuel per ton
----------------------------------------------------------------------------------------------------------------
M1................................... 2.5 MW DEG............. ULSD................... <bullet> Fuel Injection
Timing Retard (FITR)--
$5,328/ton of NOX.
<bullet> FITR + CEMS--
$12,430/ton of NOX.
<bullet> Tier 4
Replacement--$37,758/
ton of NOX.
<bullet> SCR--$40,396/
ton of NOX.
M2................................... 2.5 MW DEG............. ULSD................... <bullet> FITR--$9,186/
ton of NOX.
<bullet> Tier 4
Replacement--$62,314/
ton of NOX.
<bullet> SCR--$69,251/
ton of NOX.
M3................................... 2.5 MW DEG............. ULSD................... <bullet> FITR--$5,328/
ton of NOX.
<bullet> FITR + CEMS--
$12,430/ton of NOX.
<bullet> Tier 4
Replacement--$37,689/
ton of NOX.
<bullet> SCR--$40,395/
ton of NOX.

[[Page 7214]]

M4................................... 5.6 MW DEG............. Diesel Fuel Oil No. 6 <bullet> SCR--$9,267/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> Diesel
Particulate Filters
(DPFs)--$51,828/ton of
PM10.
<bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur
content--$10,347/ton
of SO2.
M5................................... 5.6 MW DEG............. Diesel Fuel Oil No. 6 <bullet> SCR for M5--
with 0.4% maximum $9,056/ton of NOX.
sulfur content. <bullet> DPFs--$65,963/
ton of PM10.
<bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur
content--$10,347/ton
of SO2.
M6................................... 5.6 MW DEG............. Diesel Fuel Oil No. 6 <bullet> SCR--$12,250/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> DPFs--$65,953/
ton of PM10.
<bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur
content--$10,347/ton
of SO2.
M7................................... 5.6 MW DEG............. Diesel Fuel Oil No. 6 <bullet> SCR--$7,753/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> DPFs--$60,466/
ton of PM10.
<bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur content
$10,347/ton of SO2.
M8................................... 5.6 MW DEG............. Diesel Fuel Oil No. 6 <bullet> SCR--$14,373/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur content
$10,347/ton of SO2.
M9................................... 5.6 MW DEG............. Diesel Fuel Oil No. 6 <bullet> SCR--$8,624/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur content
$10,347/ton of SO2.
M10.................................. 12.5 MW DEG............ Diesel Fuel Oil No. 6 <bullet> SCR--$6,258/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur content
$10,347/ton of SO2.
M11.................................. 12.5 MW DEG............ Diesel Fuel Oil No. 6 <bullet> SCR--$7,174/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur content
$10,347/ton of SO2.
M12.................................. 12.5 MW DEG............ Diesel Fuel Oil No. 6 <bullet> SCR--$7,256/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur content
$10,347/ton of SO2.
M13.................................. 12.5 MW DEG............ Diesel Fuel Oil No. 6 <bullet> SCR--$7,020/
with 0.4% maximum ton of NOX.
sulfur content. <bullet> Fuel switch to
ULSD with 0.0015%
maximum sulfur content
$10,347/ton of SO2.
X1................................... 2.5 MW DEG............. ULSD................... <bullet> SCR--$106,612/
ton of NOX.
X2................................... 2.5 MW DEG............. ULSD................... <bullet> SCR--$105,025/
ton of NOX.
M14.................................. 20 MW Combustion Diesel Fuel Oil No. 2 <bullet> SCR--$11,060/
Turbine. with 0.4% maximum ton of NOX.
sulfur content and <bullet> Fuel switch to
0.0015% average ULSD with 0.0015%
nitrogen content. maximum sulfur content
$10,347/ton of SO2.
M16.................................. 20 MW Combustion Diesel Fuel Oil No. 2 <bullet> SCR--$9,579/
Turbine. with 0.4% maximum ton of NOX.
sulfur content and <bullet> Fuel switch to
0.0015% average ULSD with 0.0015%
nitrogen content. maximum sulfur content
$10,347/ton of SO2.
M17.................................. 20 MW Combustion Diesel Fuel Oil No. 2 <bullet> SCR--$12,314/
Turbine. with 0.4% maximum ton of NOX.
sulfur content and <bullet> Fuel switch to
0.0015% average ULSD with 0.0015%
nitrogen content. maximum sulfur content
$10,347/ton of SO2.
M19.................................. 20 MW Combustion Diesel Fuel Oil No. 2 <bullet> SCR--$14,224/
Turbine. with 0.4% maximum ton of NOX.
sulfur content and <bullet> Fuel switch to
0.0015% average ULSD with 0.0015%
nitrogen content. maximum sulfur content
$10,347/ton of SO2.
----------------------------------------------------------------------------------------------------------------

Table 7--Four-Factor Analysis for the Mauna Loa Macadamia Nut Corporation Plant
----------------------------------------------------------------------------------------------------------------
Control measure & cost
Unit Description Primary fuel per ton
----------------------------------------------------------------------------------------------------------------
Main Boiler.......................... 35.7 MMBtu/hr.......... Biomass/Used Oil....... <bullet> The Main
Boiler committed to an
enforceable shutdown
by December 31, 2026,
and is therefore not
subject to a four-
factor analysis at
this time.
Backup Boiler........................ 14.7 MMBtu/hr.......... ULSD................... <bullet> Economizer--
$61,615/ton of NOX.
<bullet> Low NOX Burner
for Backup Boiler--
$8,208/ton of NOX.
<bullet> SCR for Backup
Boiler--$22,652/ton of
NOX.
DEG 1................................ 460 kW................. ULSD................... <bullet> SCR--$11,167/
ton of NOX.
<bullet> Tier 4
Replacement for DEG 1
& DEG 2--$11,167/ton
NOX.

[[Page 7215]]

DEG 2................................ 460 kW................. ULSD................... <bullet> SCR--$7,525/
ton NOX.
<bullet> Tier 4
Replacement for DEG 1
& DEG 2--$11,167/ton
NOX.
----------------------------------------------------------------------------------------------------------------

b. Remaining Useful Life
To further evaluate potential emission reduction measures for the
selected stationary sources, HDOH took into consideration the remaining
useful life of the units at each source. Determining the remaining
useful life involves collecting information on how long the source will
remain in operation and the lifetime of the potential control measures.
In accordance with the EPA's Control Cost Manual, HDOH used 30
years for the remaining useful life for retrofitting boilers with SCR
and wet scrubber systems at the power plants and 20 years for the
remaining useful life for all other control equipment, with the
exception of units for which HDOH established enforceable shutdown
dates. HDOH also did not factor remaining useful life for fuel
switching as it does not require capital investments in new equipment.
Specifically, at Maalaea Generating Station, the source's owner,
Hawaiian Electric provided SCR cost tables factoring a proposal to shut
down DEGs M10 and M11 by December 31, 2032 (remaining useful life of 5
years after installation of controls) and December 31, 2037, for M7,
M12, and M13 (remaining useful life of 10 years after installation of
controls). The years selected for shutdown would render SCR control
costs ineffective for each unit based on the updated $6,800/ton of
pollutant threshold set by the State, and as all shutdown dates would
occur after the second implementation period, the associated emissions
reductions were not considered when calculating 2028 RPGs. The SIP
required Hawaiian Electric to commit to these enforceable shutdowns if
SCR controls are not operational by December 31, 2027, for DEGs M7 and
M10-M13. Similarly, Hawaiian Electric proposed an enforceable shut down
date of December 31, 2028, for Boilers Hill 5 and Hill 6 at the
Kanoelehua-Hill Power Plant and Boilers K-1, K-2, K-3, and K-4 at the
Kahului Power Plant and excluded them from further emissions control
evaluation on the basis of their remaining useful life. The Mauna Loa
Macadamia Nut Corporation committed to an enforceable shutdown of
December 31, 2026, for its main boiler, but plans to replace this unit
with a new boiler following the shutdown.
c. Time Necessary for Compliance
Based on information collected in the four-factor analyses for each
facility, the State determined the following amounts of time necessary
to implement regional haze control measures:
<bullet> Four years from permit issuance for switching fuel for the
Puna Generating Station Boiler to ULSD. (Permit Amended August 10,
2022, therefore, fuel switch is required by August 10, 2026.)
<bullet> December 31, 2027, for installing FITR on M1 and M3 at
Maalaea Generating Station
<bullet> December 31, 2027, for installing SCR for M7 and M10
through M13 at Maalaea Generating Station. These units may also shut
down by the following dates as an alternative option to installing SCR:
[cir] December 31, 2037, for M7;
[cir] December 31, 2030, for M10 and/or M11;
[cir] December 31, 2032, for M10 or M11 if one of these units is
shut down by 2030 or installs SCR, and
[cir] December 31, 2037, for M12 and M13.
<bullet> December 31, 2026, for the main boiler at the Mauna Loa
Macadamia Nut Corporation Plant. The main boiler will be replaced with
another unit after the existing unit is shutdown.
d. Energy and Non-Air Environmental Impacts
Based on information collected in the Hawaiian Electric four-factor
analyses for their facilities, the State determined the following
energy and non-air environmental impacts:
<bullet> Fuel Switching--There are no energy and non-air quality
environmental impacts of compliance for fuel switching.
<bullet> Circulating Dry Scrubber (CDS)--CDS systems require
electricity to operate the ancillary equipment. In addition, solid
waste streams are generated that require disposal.
<bullet> DPFs--There are no energy and non-air quality
environmental impacts of compliance for adding DPFs.
<bullet> SCR and SNCR--These control systems require electricity to
operate the ancillary equipment. SCR and SNCR can potentially cause
environmental impacts related to storage of ammonia. These control
systems can also release unreacted ammonia, known as ammonia slip.
<bullet> Wet ESPs--ESPs apply energy for removing particulate from
the exhaust stream of the emissions source. Wet ESPs generate
wastewater streams that must be treated onsite or sent to a wastewater
treatment plant. The wastewater treatment process will generate filter
cake that would likely require landfilling.
<bullet> Wet Scrubbers--Wet scrubbers require energy to force
exhaust gases through the scrubber and generate wastewater streams that
would need to be treated.
Similarly, based on information provided by the Mauna Loa Macadamia
Nut Corporation Plant, the State determined the following energy and
non-air environmental impacts:
<bullet> LNB--Electrical usage is increased by installing three
horsepower combustion air fans to accommodate LNB.
<bullet> SCR--Electrical usage increases due to an increase in
combustion air motor horsepower to accommodate pressure drop from
installing SCR.
4. Control Determinations
Hawaii's control measure determinations, including the specific
permit conditions submitted to the EPA for approval into the Hawaii SIP
by incorporation by reference, are summarized in Table 8 of this
document. These permit conditions include the relevant shutdown dates,
emissions limitations, compliance dates, and monitoring, recordkeeping,
and reporting requirements to ensure the enforceability of the
associated emissions limitations. Some emissions controls are included
in the 2028 RPGs, and HDOH estimated the emissions reductions to be:
610 tpy NO<INF>X</INF>, 2,351 tpy SO<INF>2</INF>, 65 tpy
PM<INF>10</INF> for controls selected for Hawaii Island Sources and
2,444 tpy NO<INF>X</INF>, 2,221 tpy SO<INF>2</INF>, 84 tpy
PM<INF>10</INF> for controls selected for Maui Island Sources. HDOH
indicated that the State's calculations of 2028 RPGs does not include
the anticipated emissions reductions from the shutdown of the main
boiler at the Mauna Loa Macadamia Nut Corporation Plant as it

[[Page 7216]]

was uncertain what amount of NO<INF>X</INF> reduction will occur from
the boiler replacement.\69\
---------------------------------------------------------------------------

\69\ Appendix V ``Regional Haze Adjusted Reasonable Progress
Goals'' to the 2024 Hawaii Regional Haze Plan, pp. 8-11.

Table 8--Hawaii Regional Haze New Control Measure Determinations
--------------------------------------------------------------------------------------------------------------------------------------------------------
Compliance Relevant permit
Source Unit Control Pollutant deadline conditions
--------------------------------------------------------------------------------------------------------------------------------------------------------
Kanoelehua-Hill Power Plant..... Boiler Hill 5........ Shutdown..................... NOX, SO2, PM10.......... December 31, 2028. Permit Amendment
for Covered
Source Permit
(CSP) No. 0234-01-
C Special
Condition No.
C.1.
Boiler Hill 6........ Shutdown..................... NOX, SO2, PM10.......... December 31, 2028. Permit Amendment
for CSP No. 0234-
01-C Special
Condition No.
C.1.
Mauna Loa Macadamia Nut Main Boiler.......... Shutdown \a\................. ........................ December 31, 2026. Permit Amendment
Corporation Plant. for CSP No. 0317-
01-C, Permit
Conditions C.1
and C.2.
Puna Power Plant................ Puna Boiler.......... Fuel Switch to ULSD.......... NOX, SO2, PM10.......... August 10, 2026... Permit Amendment
for CSP No. 0235-
01-C, Permit
Conditions C.1
and C.2.
Kahului Power Plant............. Boiler K-1........... Shutdown..................... NOX, SO2, PM10.......... December 31, 2028. Permit Amendment
for CSP No. 0232-
01-C, Special
Condition No.
C.1.
Boiler K-2........... Shutdown..................... NOX, SO2, PM10.......... December 31, 2028. Permit Amendment
for CSP No. 0232-
01-C, Special
Condition No.
C.1.
Boiler K-3........... Shutdown..................... NOX, SO2, PM10.......... December 31, 2028. Permit Amendment
for CSP No. 0232-
01-C, Special
Condition No.
C.1.
Boiler K-4........... Shut down.................... NOX, SO2, PM10.......... December 31, 2028. Permit Amendment
for CSP No. 0232-
01-C, Special
Condition No.
C.1.
Maalaea Generating Station...... DEG M1............... FITR......................... NOX..................... December 31, 2027. Permit Amendment
for CSP No. 0067-
01-C, Permit
Condition C.2.
DEG M3............... FITR......................... NOX..................... December 31, 2027. Permit Amendment
for CSP No. 0067-
01-C, Permit
Condition C.2.
DEG M7............... SCR or Shutdown.............. NOX..................... December 31, 2027 Permit Amendment
for SCR OR for CSP No. 0067-
December 31, 2037 01-C, Permit
for shut down. Condition C.3.
DEG M10.............. SCR or Shutdown.............. NOX..................... December 31, 2027 Permit Amendment
for SCR OR for CSP No. 0067-
December 31, 2030 01-C, Permit
for shut down \b\. Condition C.4.
DEG M11.............. SCR or Shutdown.............. NOX..................... December 31, 2027 Permit Amendment
for SCR OR for CSP No. 0067-
December 31, 2030 01-C, Permit
for shut down \b\. Condition C.4.
DEG M12.............. SCR or Shutdown.............. NOX..................... December 31, 2027 Permit Amendment
for SCR OR for CSP No. 0067-
December 31, 2037 01-C, Permit
for shut down. Condition C.5.
DEG M13.............. SCR or Shutdown.............. NOX..................... December 31, 2027 Permit Amendment
for SCR OR for CSP No. 0067-
December 31, 2037 01-C, Permit
for shut down. Condition C.5.
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2024 Hawaii Regional Haze Plan, p. 97, and Appendix X to the 2024 Hawaii Regional Haze Plan.
\a\ The main boiler will be replaced with another unit after existing unit is shut down. The replacement unit will be subject to a four-factor analysis
or effective controls determination.
\b\ If either DEG M10 or M11 installs SCR by December 31, 2027, or shuts down by December 31, 2030, the deadline to shut down date the remaining unit is
then December 31, 2032.

5. Additional Long-Term Strategy Requirements
Pursuant to 40 CFR 51.308(f)(2)(iv)(A), Hawaii detailed the
existing and ongoing State and Federal emission control programs that
contribute to emission reductions through 2028.\70\ These programs
include the State's: Renewable Portfolio Standards, Energy Efficiency
Portfolio Standard, Greenhouse Gas Rules, along with other ongoing
federal programs. Additionally, the State highlighted Hawaii
Administrative Rules that mitigate the impacts of construction
activities as required by 40 CFR 51.308(f)(2)(iv)(B).\71\
---------------------------------------------------------------------------

\70\ 2024 Hawaii Regional Haze Plan, Chapter 7.1 and 7.2.
\71\ Id. Chapter 7.3.
---------------------------------------------------------------------------

Pursuant to 40 CFR 51.308(f)(2)(iv)(C), source retirements and
replacement schedules are addressed in the 2024 Hawaii Regional Haze
Plan. In accordance with Hawaiian Electric's 2023 ``Integrated Grid
Plan'' to meet the 100% renewable portfolio standard goal by 2045,\72\
HDOH anticipates that numerous generating units will be replaced with
sources of renewable energy.\73\
---------------------------------------------------------------------------

\72\ Executive Summary of the Hawaiian Electric ``Integrated
Grid Plan,'' May 2023.
\73\ Tabulated in Table 7.4-1 of the 2024 Hawaii Regional Haze
Plan.
---------------------------------------------------------------------------

Regarding the consideration of smoke management practices required
by 40 CFR 51.308(f)(2)(iv)(D), HDOH explained that the State does not
have a smoke management plan. Instead, planned open burning is
regulated under the Hawaii Administrative Rules 11-60.1, Subchapter
3.\74\
---------------------------------------------------------------------------

\74\ Refer to Appendix O of the 2024 Hawaii Regional Haze Plan.
---------------------------------------------------------------------------

The State also considered the anticipated net effect of projected
changes in emissions as required by 40 CFR 51.308(f)(2)(iv)(E) by
discussing the

[[Page 7217]]

process and criteria used to select point sources of anthropogenic
emissions of NO<INF>X</INF>, SO<INF>2</INF>, and PM<INF>10</INF> with
the greatest potential impact on visibility impairment on Class I areas
in Hawaii, and further describes how sources were evaluated using
statutory factors to characterize and determine what control measures
are necessary to make reasonable progress over the second planning
period.\75\
---------------------------------------------------------------------------

\75\ Chapter 7.5 of the 2024 Hawaii Regional Haze Plan.
---------------------------------------------------------------------------

6. Conclusion
The EPA reviewed the state's long-term strategy for compliance with
the applicable requirements of the CAA and the RHR. The state included
in the Plan a description of the criteria it used to determine which
sources it evaluated and how the four factors were taken into
consideration in selecting the measures for inclusion in its long-term
strategy. As previously noted, during development of the Plan, Hawaiian
Electric agreed to enforceable shutdowns at several EGUs in order to
exclude these units from further evaluation. However, on August 25,
2025, representatives of Hawaiian Electric (``the Company'') sent a
letter to the Regional Administrator for EPA Region 9, stating that:

. . . the Company was forced under the SIP to accept enforceable
retirement deadlines for units the Company plans to retire, due the
high costs of controls and fuels switches. However, these retirement
deadlines are no longer acceptable because of potential negative
impacts to generation reliability due to actual or potential
cancellations and delays in replacement generation projects that
were planned by independent power producers.\76\
---------------------------------------------------------------------------

\76\ Letter dated August 29, 2025, from Karin Kimura, Director,
Environmental Division, Hawaiian Electric, to Josh F.W. Cook,
Regional Administrator, EPA Region 9, pp. 1-2.

The Company then explained that 115 MW of planned generation had
been cancelled on the island of Hawaii, meaning that, ``grid
reliability will be at risk in 2029 following the retirement of the
Kanoelehua-Hill boilers.'' In addition, the Company similarly noted
that 20 MW of planned generation had been cancelled for Maui, and thus
``a delay to the shutdown of the Kahului boilers and Maalaea generating
units would reduce reliability risks,'' if there were delays with
additional replacement generation projects on Maui.\77\ Citing Adequacy
of Supply Reports dated January 30, 2025 for Hawaiian Electric Light
Company and Maui Electric Company, the Company stated that ``retirement
of the generating units as required by the SIP deadlines will create
higher probability of energy reserve margin shortfalls that increase
risk to reliability on both islands.'' \78\ The Company also emphasized
that ``each island must be entirely self-sufficient and cannot rely on
power by wire transmission from other jurisdictions as is common in the
continental United States to address reliability emergencies.'' Thus,
Hawaii's long-term strategy includes source closures that are now
opposed by the sources' owner (hereinafter ``forced'' or
``unconsented'' closures). As detailed in the paragraphs below, the EPA
proposes to find that these unconsented closures are inconsistent with
CAA section 110 because the State has not provided necessary assurances
that these measures would not violate state or federal law as required
by CAA section 110(a)(2)(E)(i). We are also relying on and
incorporating the arguments set forth in the EPA's final action
disapproving the Colorado Regional Haze Plan for the Second
Implementation Period,\79\ and the EPA's final action partially
disapproving the California Heavy-Duty Vehicle Inspection and
Maintenance Program to the extent applicable to this proposed partial
approval and partial disapproval of the Plan.\80\
---------------------------------------------------------------------------

\77\ Id. at 3.
\78\ Id.
\79\ 91 FR 3048 (January 26, 2026).
\80\ Available at <a href="https://www.epa.gov/system/files/documents/2026-01/pre-pub-frl-12606-02-r9-hd-im-final-nfrm.pdf">https://www.epa.gov/system/files/documents/2026-01/pre-pub-frl-12606-02-r9-hd-im-final-nfrm.pdf</a>.
---------------------------------------------------------------------------

CAA section 110(a)(2)(E)(i) provides that state plans must provide
``necessary assurances'' that the State ``is not prohibited by any
provision of Federal or State law from carrying out such implementation
plan or portion thereof.'' The best reading of this provision is that
the EPA may not approve a SIP revision that risks violating federal or
state law in the course of implementation and for which the state has
not provided necessary assurances that there will be no such violation.
This reading is consistent with the EPA's independent obligation to
follow Federal constitutional and statutory law and with the structure
of CAA section 110 as a whole, which sets out detailed requirements for
state plans and for the EPA's review of such plans. The EPA proposes to
find that approval by the EPA of unconsented source closures, without
just compensation, could violate the Takings Clause of the U.S.
Constitution and possibly comparable provisions of state law, and that
Hawaii has not provided the necessary assurances that such violations
would not occur.\81\
---------------------------------------------------------------------------

\81\ U.S. Constitution amendments V, XIV; see also Hawaii
Constitution article I, section 20.
---------------------------------------------------------------------------

Although the application of the Takings Clause is necessarily fact-
specific, EPA approval of an unconsented source closure could
constitute a per se taking or a total or partial regulatory taking
without just compensation. The EPA notes that there is a lack of
controlling precedent on application of the Takings Clause to approval
of unconsented source closures under CAA section 110 because states
typically do not require such unconsented closures.\82\ U.S. Supreme
Court precedent suggests, however, that the EPA's approval of such
forced closures could amount to a per se taking. In Cedar Point Nursery
v. Hassid, 594 U.S. 139 (2021), the U.S. Supreme Court explained that
government action that appropriates property ``is no less a physical
taking because it arises from a regulation.'' Particularly relevant
here, the Court applied the per se bar on uncompensated takings in
Horne v. Department of Agriculture, 576 U.S. 351 (2015), to a complex
regulatory regime that required regulated parties to set aside a
portion of their output to achieve governmental aims. The EPA proposes
to conclude that Hawaii has not provided the necessary assurances
required by CAA section 110(a)(2)(E)(i) that approval of the submitted
closure provisions would not result in uncompensated per se takings in
violation of Federal and possibly state law.
---------------------------------------------------------------------------

\82\ As previously noted, at the time that Hawaii adopted the
closures at issue here, they were not unconsented.
---------------------------------------------------------------------------

Relatedly, a total regulatory taking could occur if the closure
would fully deprive the source owner of all economic use of the land
under the standard described in Lucas v. S.C. Coastal Council, 505 U.S.
1003, 1116 (1992). A partial regulatory taking could occur if the
closure inflicted a significant economic impact upon the source owner,
undermined distinct, investment-backed expectations, and shared
characteristics with actions conventionally regarded as government
takings. These factors and how courts should balance them are detailed
in Penn Central Transp. Co. v. New York City, 438 U.S. 104, 123 (1978),
and subsequent cases. While the EPA proposes to find that the Hawaii
SIP must be disapproved because the state has failed to provide
necessary assurances that a per se taking will not result from EPA
approval of the forced

[[Page 7218]]

unconsented closures, the state also has an obligation to provide
necessary assurances that a partial or total regulatory taking will not
occur.
Furthermore, although it is not a basis for disapproval in this
instance, we find that Hawaii's long-term strategy did not adequately
consider the energy impacts associated with EGU closures. More
specifically, we find Hawaii did not sufficiently assess the closures'
impacts on maintaining grid reliability and Hawaiian Electric's ability
to meet energy demand. This finding is supported by documentation from
Hawaiian Electric regarding risk to energy availability and grid
reliability due to source closures incorporated into Hawaiian long-term
strategy.
The 2024 Hawaii Regional Haze Plan partially addressed the ``energy
and nonair quality environmental impacts of compliance'' statutory
factor by describing the nonair quality impacts of specific controls
options. However, because Hawaii lacked material information about grid
reliability, later provided to the EPA by Hawaiian Electric, we find
that the State did not appropriately weigh the energy impacts of the
closure measures in its long-term strategy. Nonetheless, despite the
shortcomings in Hawaii's analysis of grid reliability concerns, the EPA
recognizes that our prior statements may have generated a reliance
interest that led to how Hawaii developed its SIP revision.\83\ For
example, the EPA's 2019 Guidance provided a limited scope of
considerations generally involved under the ``energy and non-air
quality factor,'' which did not include grid reliability. It was
reasonable for Hawaii to rely on the interpretation provided in that
guidance. Therefore, recognizing Hawaii's reliance interest in the
EPA's prior representations, the EPA is not determining that Hawaii's
limited consideration of grid reliability is a reason to disapprove the
source closures.
---------------------------------------------------------------------------

\83\ See, e.g., Kentucky v. EPA, 123 F. 4th 447, 467-71 (4th
Cir. 2025).
---------------------------------------------------------------------------

Finally, the EPA also proposes that the forced source closure
contained in this portion of the State's submission are inconsistent
with the structure of CAA sections 110 and 169A, which do not expressly
contemplate forced closures as a means to achieve compliance. In this
context, we are referring to a source closure opposed by the source in
question that would be made federally enforceable as a result of a SIP
approval.
We are seeking comment and proposing that the best reading of the
phrase ``other control measures, means, or techniques'' does not
encompass the authority to force a source to close, or to close on
timeframe not agreed to by the owner/operator. This proposal is
supported by reading the terms ``measures'' and ``means'' in context
and informed by the surrounding statutory terms, including the
parenthetical phrase discussing market-based incentives that
contemplate ongoing operations. ``Measures'' and ``means'' must also be
``necessary or appropriate'' to meet applicable CAA requirements. As
noted above, the EPA is proposing that unconsented closures are neither
``necessary'' under the circumstances here nor otherwise required by
the CAA, and that such closures are not ``appropriate'' when they could
amount to an uncompensated taking in violation of federal and state
law. The EPA seeks comment on this interpretation.
CAA section 169A similarly does not contemplate use of unconsented
closures as part of the regional haze program. The statute provides
that state plans must contain ``emission limits, schedules of
compliance and other measures as may be necessary to make reasonable
progress,'' including through the use of ``retrofit technology'' and
long-term strategies. Consistent with the interpretation of CAA section
110 proposed above, the EPA proposes that the best reading of the
statute does not require or authorize the use of forced source closures
to attain the statutory goals listed in CAA section 169A. The EPA seeks
comment on this interpretation as well.
In summary, Hawaii did not provide necessary assurances that the
unconsented closures in the long-term strategy would not violate
federal and possibly state law, as required by CAA section
110(a)(2)(E)(i). Thus, the long-term strategy does not meet this CAA
requirement and does not meet 40 CFR 51.308(f)(2). Under CAA section
110(k)(3), the EPA cannot approve a plan revision or a portion thereof,
unless it meets all applicable plan requirements. Therefore, we are
proposing to disapprove Hawaii's long-term strategy.

F. Reasonable Progress Goals

Section 51.308(f)(3) contains the requirements pertaining to RPGs
for each Class I area. Because Hawaii is host to Class I areas, it is
subject to both section 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 emission
limitations, compliance schedules and other measures required under
paragraph (f)(2) to be in states' long-term strategies, as well as
implementation of other CAA requirements. The long-term strategies as
reflected by the RPGs must provide for an improvement in visibility on
the most impaired days relative to the baseline period and ensure no
degradation on the clearest days relative to the baseline period.
Section 51.308(f)(3)(ii) applies in circumstances in which a Class I
area's RPG for the most impaired days represents a slower rate of
visibility improvement than the uniform rate of progress calculated
under 40 CFR 51.308(f)(1)(vi). Under Sec. 51.308(f)(3)(ii)(A), if the
state in which a mandatory Class I area is located establishes an RPG
for the most impaired days that provides for a slower rate of
visibility improvement than the URP, the state must demonstrate that
there are no additional emission reduction measures for anthropogenic
sources or groups of sources in the state that would be reasonable to
include in its long-term strategy. Section 51.308(f)(3)(ii)(B) requires
that if a state contains sources that are reasonably anticipated to
contribute to visibility impairment in a Class I area in another state,
and the RPG for the most impaired days in that Class I area is above
the URP, the upwind state must provide the same demonstration.
HDOH estimated RPGs starting with the selection of the 20 percent
Most Impaired Days and the EPA modeled projection to 2028, followed by
three adjustment procedures: scaling of EPA modeling results to reflect
emissions controls, an adjustment to reflect the presence of volcanic
SO<INF>2</INF> emissions, and normalization of the RPG to better
reflect the EPA tracking guidance-recommended calculation of dv.\84\ To
calculate RPGs for 2028, HDOH began with projected visibility
conditions for 2028 from WRAP's TSS website. These initial 2028
visibility conditions were based on photochemical modeling conducted by
the EPA to project Class I visibility conditions on the 20 percent most
impaired days and the 20 percent clearest days for 2028 in Alaska,
Hawaii, and the Virgin Islands using the Community Multiscale Air
Quality model.\85\ Input files for the modeling

[[Page 7219]]

included hourly emission estimates, meteorological data, and boundary
concentrations to create modeled simulations of visibility for a 2016
base year case, a 2028 case, and 2028 U.S anthropogenic emissions zero-
out model run. The modeling did not include emissions from volcanoes.
The IMPROVE data were screened to remove days with episodically high
concentrations due to natural sources, so that the 20 percent most
impaired days better reflected anthropogenic impairment, following the
2021 Hawaii Visibility Data Adjustment Memo, described and cited above.
However, as previously noted, even these adjusted values include some
volcanic impacts and thus the 2028 projections for the twenty percent
most impaired days also include such impacts. The PM predictions from
the 2016 and 2028 EPA model simulations were used to project 2014-2018
IMPROVE visibility data to 2028 following the approach described in the
EPA's ozone, PM<INF>2.5</INF>, and regional haze modeling guidance.\86\
---------------------------------------------------------------------------

\84\ Hawaii Regional Haze Plan, Appendix V. An annotated
spreadsheet replicated the Appendix V RPG calculations is included
in the docket for this rulemaking.
\85\ ``Technical Support Document for EPA's Updated 2028
Regional Haze Modeling for Hawaii, Virgin Islands, and Alaska.''
EPA-454/R-21-007, August 2021. This original modeling projected 2028
from IMPROVE data for 2014-2017, but the WRAP TSS has the model
outputs reprocessed to project 2028 from 2014-2018 IMPROVE data.
\86\ Memorandum dated November 29, 2018, from Richard Wayland,
Director, Air Quality Assessment Division, to Regional Air
Directors, Regions 1-10, Subject: ``Modeling Guidance for
Demonstrating Air Quality Goals for Ozone, PM<INF>2.5</INF>, and
Regional Haze.''
---------------------------------------------------------------------------

As described in more detail in Appendix V to the 2024 Hawaii
Regional Haze SIP, HDOH adjusted the WRAP TSS 2028 projections to
reflect the impact of enforceable regional haze control measures
adopted in the long-term strategy (Kahului Generating Station--boiler
shutdowns, Kanoelehua-Hill Generating Station--boiler shutdowns,
Maalaea Generating Station--DEG retrofits with FITR and SCR, and Puna
Generating Station--boiler fuel switch to ultralow sulfur diesel).
HDOH's adjusted RPGs for its Class I areas (represented by the
IMPROVE monitor), from appendix V of the 2024 Hawaii Regional Haze Plan
are shown in Table 9 of this document, along with baseline conditions
and the 2028 URP (for the most-impaired days) and initial 2028 model
projections from Tables 8-2-1 and 8-3-1 of the Plan.

Table 9--Hawaii Baseline Conditions, Adjusted URP and 2028 RPGs
--------------------------------------------------------------------------------------------------------------------------------------------------------
20% Most-impaired days 20% Clearest days
-------------------------------------------------------------------------------
Class I area Site 2000-2004 2000-2004
Baseline 2028 URP 2028 RPG Baseline 2028 RPG
--------------------------------------------------------------------------------------------------------------------------------------------------------
Haleakala National Park................... HALE1....................... 7.8 6.4 6.5 2.2 0.4
Hawaii Volcanoes National Park............ HAVO1....................... 15.6 12.0 15.1 4.1 3.2
--------------------------------------------------------------------------------------------------------------------------------------------------------
Source: 2024 Hawaii Regional Haze Plan, Tables 8-2-1 and 8-3-1, and Appendix V, Tables V-1 and V-2.

As described in Section IV.E.6 of this document, we are proposing
to disapprove Hawaii's long-term strategy under 51.308(f)(2). Section
51.308(f)(3)(i) specifies that RPGs must reflect ``enforceable
emissions limitations, compliance schedules, and other measures
required under paragraph (f)(2) of this section.'' We commend Hawaii
for setting reasonable progress goals in an effort to meet the
requirements of 51.308(f)(3). However, in the absence of an approved
long-term strategy, we cannot approve the associated RPGs.
We also note that for this planning period, both Class I areas
within Hawaii have RPGs for the 20 percent most impaired days that
provide for a slower rate of visibility improvement than the URP by
2028.\87\ Specifically, the HALE1 IMPROVE monitor at the Haleakala
National Park is projected to be 0.1 dv above the URP in 2028, and the
HAVO1 IMPROVE monitor at the Hawaii Volcanoes National Park is
projected be 3.1 dv above the URP in 2028. Section 51.308(f)(3)(ii) of
the Regional Haze Rule requires that if a state adopts an RPG for the
most impaired days that provides for a slower rate of improvement in
visibility than the uniform rate of progress, i.e., if the RPG is above
the URP glidepath, it must include within its SIP submission an
assessment of the number of years it would take to attain natural
visibility conditions if visibility improvement were to continue at the
rate of progress selected by the state as reasonable for the
implementation period. Based on the visibility measured for the most
impaired days between 2004 and the 2028 RPGs, the State calculated that
it would take 409 years to reach the natural visibility level at the
Hawaii Volcanoes National Park and 67 years to reach the natural
visibility level at the Haleakala National Park. As previously stated
in section IV.F, despite adjustments intended to screen out the
influence from volcanic emissions, the influence remains to an unknown
extent within the calculated 2028 projections for the twenty percent
most impaired days. As a result, there is uncertainty in the projection
of the URP.
---------------------------------------------------------------------------

\87\ 2024 Hawaii Regional Haze Plan, Chapter 8.2 and 8.3.
---------------------------------------------------------------------------

The Regional Haze Rule also requires that states with Class I areas
and any other states with sources affecting that area make a ``robust
demonstration'' that there are no additional emissions reduction
measures for sources that may reasonably be anticipated to contribute
to visibility impairment that would be reasonable to include in the
long-term strategy. The robust demonstration requires an analysis to
ensure there are no additional emissions reduction measures that would
be reasonable to include in the long-term strategy. HDOH asserts that
it has already conducted a source selection and control measures
analyses in such a manner that addresses the requirements of 40 CFR
51.308(f)(3)(ii). Specifically, HDOH cites its four-factor analyses in
Chapter 6 and associated appendices of the 2024 Hawaii Regional Plan as
constituting the required robust demonstration for selecting reasonable
regional haze control measures in accordance with the applicable
provisions of the RHR. Because we are proposing to find that Hawaii has
not met the requirements of 51.308(f)(2), we also propose to find that
it has not satisfied 51.308(f)(3)(ii).
In sum, we propose to disapprove the RPGs in the Plan as not
meeting the requirements of 40 CFR 51.308(f)(3).

G. Monitoring Strategy and Other Implementation Plan Requirements

Section 51.308(f)(6) specifies that each comprehensive revision of
a state's regional haze SIP must contain or provide for certain
elements, including monitoring strategies, emissions inventories, and
any reporting, recordkeeping and other measures needed to assess and
report on visibility. A main requirement of this

[[Page 7220]]

subsection is for states with Class I areas to submit monitoring
strategies for measuring, characterizing, and reporting on visibility
impairment. Compliance with this requirement may be met through
participation in the IMPROVE network.
Chapter 9.1 of the 2024 Hawaii Regional Haze Plan states that
Hawaii is relying on the continued availability of the IMPROVE program
in meeting the monitoring operation, collection, and reporting
requirements for measuring visibility impairment in its Class I areas.
Section 51.308(f)(6)(i) requires SIPs to provide for the
establishment of any additional monitoring sites or equipment needed to
assess whether reasonable progress goals to address regional haze for
all mandatory Class I Federal areas within the state are being
achieved. To satisfy this requirement, the State commits to work with
IMPROVE, the EPA, and FLMs to ensure that representative monitoring
continues for its Class I areas. HDOH asserts that the visibility data
for Haleakala National Park and Hawaii Volcanoes National Park are
adequate for assessing the RPGs and no additional monitoring sites are
necessary at this time.
Section 51.308(f)(6)(ii) requires SIPs to provide for procedures by
which monitoring data and other information are use 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. HDOH highlights Chapter 3, Chapter 5, Chapter 6,
and Chapter 7 of the 2024 Hawaii Regional Haze plan as describing the
procedures by which the relative impact of emissions on Class I areas
in the state are assessed. Chapter 4 described the procedures used to
produce the statewide emissions inventory of pollutants reasonably
anticipated to cause or contribute to visibility impairment in Hawaii's
Class I areas.
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. HDOH notes that,
while the agency does not directly collect or handle IMPROVE data, it
will remain a part of the WRAP program and participate in the exchange
of IMPROVE information for developing and updating the WRAP TSS.
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. HDOH asserts that Hawaii, with support from
WRAP, shows a statewide inventory of emissions that can be reasonably
expected to cause or contribute to visibility impairment in Class I
areas. Hawaii commits to updating statewide emission periodically, and
these updates will be used for Hawaii's tracking of emission changes,
trends, and evaluation of whether reasonable progress goals are being
achieved along with other regional analyses. The updates will occur
every three years on the same schedule as the triennial reporting
required by the EPA's Air Emissions Reporting Rule (AERR) in 40 CFR
part 51 Subpart A.
The EPA proposes to find that Hawaii has met the requirements of 40
CFR 51.308(f)(6) as described in the preceding paragraphs, including
through its continued participation in the IMPROVE network and the WRAP
RPO and its ongoing compliance with the AERR. We also propose to find
that no further elements are necessary at this time for Hawaii to
assess and report visibility pursuant to 40 CFR 51.308(f)(6)(vi).

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

Section 51.308(f)(5) requires that periodic comprehensive revisions
of states' regional haze plans also address the progress report
requirements of 40 CFR 51.308(g)(1) through (5). The purpose of these
requirements is to evaluate progress towards the applicable RPGs for
each Class I area within the state and each Class I area outside the
state that may be affected by emissions from within that state.
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 emission reductions achieved through implementation of those
measures. Section 51.308(g)(3) applies only to states with Class I
areas within their borders and requires such states to assess current
visibility conditions, changes in visibility relative to baseline
(2000-2004) visibility conditions, and changes in visibility conditions
relative to the period addressed in the first implementation period
progress report. Section 51.308(g)(4) applies to all states and
requires an analysis tracking changes in emissions of pollutants
contributing to visibility impairment from all sources and sectors
since the period addressed by the first implementation period progress
report. This provision further specifies the year or years through
which the analysis must extend depending on the type of source and the
platform through which its emission information is reported. Finally,
section 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. Hawaii submitted its
first planning period progress report to the EPA on October 20, 2017,
which presented data analysis for the period of 2011 through 2015.\88\
The EPA finalized its approval of the first planning period progress
report on August 12, 2019.\89\
---------------------------------------------------------------------------

\88\ 84 FR 39754.
\89\ Id.
---------------------------------------------------------------------------

The 2024 Hawaii Regional Haze Plan describes the status of Federal
and State measures in the long-term strategy from the first
implementation period for reducing visibility impairing pollution and
provided a table of emissions reductions achieved throughout the State
due to continued measures controlling SO<INF>2</INF> emissions at oil-
fired plants on the island of Hawaii: Kanoelehua-Hill and Puna, to
3,550 tons of SO<INF>2</INF> beginning in 2018.\90\ The EPA proposes to
find that Hawaii 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.
---------------------------------------------------------------------------

\90\ 2024 Hawaii Regional Haze Plan, Chapter 9.2.
---------------------------------------------------------------------------

The 2024 Hawaii Regional Haze Plan also included summaries of the
visibility conditions and the trend of the 5-year averages through 2018
at Class I area in the State.\91\ As shown in Table 1 of this document,
the Plan included the 5-year baseline (2000-2004) visibility conditions
for the clearest and most impaired days. The 2024 Hawaii Regional Haze
Plan also included the current 5-year status (2014-2018) for the
clearest and most impaired days. The

[[Page 7221]]

Plan also tabulated the visibility metrics levels at Hawaii Class I
areas, including the 5-year rolling average for the clearest and most
impaired days.\92\ The EPA therefore proposes to find that Hawaii has
satisfied the requirements of 40 CFR 51.308(g)(3).
---------------------------------------------------------------------------

\91\ Id. Tables 9.2-2 and 9.2-3.
\92\ Id. Tables 3.1-1 and 3.1-2.
---------------------------------------------------------------------------

Pursuant to 51.308(g)(4), Hawaii provided a summary of emissions of
NO<INF>X</INF>, SO<INF>2</INF>, PM<INF>10</INF>, PM<INF>2.5</INF>,
VOCs, and NH<INF>3</INF> from all sources and activities, including
from point, nonpoint, non-road mobile, and on-road mobile sources, for
the time period from 2005 through 2017 and projected emissions for 2028
in the 2024 Hawaii Regional Haze Plan.\93\ In its analyses of the
Statewide emissions inventory, HDOH discussed the changes in emissions
by source or activity and demonstrated significant decreases in
emissions across all pollutants except for a minor five percent
increase in PM<INF>2.5</INF> emissions from 2005 to 2017. Therefore,
the EPA is proposing to find that the 2024 Hawaii Regional Haze Plan
satisfies requirements of 40 CFR 51.308(g)(4) and 40 CFR 51.308(g)(5)
by providing emissions information for NO<INF>X</INF>, SO<INF>2</INF>,
PM<INF>10</INF>, PM<INF>2.5</INF>, VOCs, and NH<INF>3</INF> broken down
by type of source. The emissions data in the SIP submission support the
assessment that anthropogenic haze-causing pollutant emissions in
Hawaii have decreased during the reporting period and that changes in
emissions have not limited or impeded progress in reducing pollutant
emission and improving visibility.
---------------------------------------------------------------------------

\93\ Id. Chapter 4.
---------------------------------------------------------------------------

I. Requirements for State and Federal Land Manager Coordination

Section 169A(d) of the Clean Air Act requires states to consult
with FLMs before holding the public hearing on a proposed regional haze
SIP, and to include a summary of the FLMs' conclusions and
recommendations in the notice to the public. In addition, section
51.308(i)(2)'s FLM consultation provision requires a state to provide
FLMs with an opportunity for consultation that is early enough in the
state's policy analyses of its emission reduction obligation so that
information and recommendations provided by the FLMs' can meaningfully
inform the state's decisions on its long-term strategy. If the
consultation has taken place at least 120 days before a public hearing
or public comment period, the opportunity for consultation will be
deemed early enough. Regardless, the opportunity for consultation must
be provided at least sixty days before a public hearing or public
comment period at the state level. Section 51.308(i)(2) also provides
two substantive topics on which FLMs must be provided an opportunity to
discuss with states: assessment of visibility impairment in any Class I
area and recommendations on the development and implementation of
strategies to address visibility impairment. Section 51.308(i)(3)
requires states, in developing their implementation plans, to include a
description of how they addressed FLMs' comments.
HDOH provided a draft of their 2024 Hawaii Regional Haze Plan to
the NPS, FWS, and the USFS on June 7, 2023.\94\ Additionally, NPS
Interior Regions 8, 9, 10, and 12, and several national park units in
Hawaii hosted a consultation meeting to discuss the regional haze
submittal. From the review of the 2024 Hawaii Regional Haze Plan, the
FLMs requested that HDOH specify additional requirements for the
Maalaea Generating Station and Mauna Loa Macadamia Nut Corporation
Plant. Specifically, a permit condition stipulating that HDOH and the
EPA are notified when the Maalaea Generating Station chooses a control
measure for M7 and M10-M13 and when the Mauna Loa Macadamia Nut
Corporation Plant provides an effective controls demonstration or
conducts a four-factor analysis for the boiler replacement was
requested. HDOH amended the relevant permits and the 2024 Hawaii
Regional Haze SIP to address these comments.
---------------------------------------------------------------------------

\94\ Id. Chapter 9.5.
---------------------------------------------------------------------------

On November 27, 2023, Hawaii provided public notice on the draft
SIP submission and associated permits and offered to hold a public
hearing on January 19, 2024.\95\ HDOH notified the public, other
interested parties, FLMs, and the EPA. The State accepted written
public comment on the 2024 Hawaii Regional Haze Plan for thirty days,
until December 26, 2023. The State later held a public hearing on April
19, 2024, in person and virtually, to receive oral testimonies on the
2024 Hawaii Regional Haze Plan and its appendices, and those
testimonies and the State's responses are provided in Appendix X of
their plan.
---------------------------------------------------------------------------

\95\ Id. Chapter 9.6.
---------------------------------------------------------------------------

However, as explained above, because the EPA is proposing to
disapprove certain elements of the Plan, namely the long-term strategy
under 51.308(f)(2) and the reasonable progress goals under
51.308(f)(3), the EPA is also proposing to disapprove the Plan with
respect to the FLM consultation requirements under 51.308(i). While
Hawaii did take administrative steps to provide the FLMs the requisite
opportunity to review and provide feedback on the state's initial draft
plan, the EPA cannot approve the requirements under 51.308(i) because
Hawaii's consultation was based on a SIP revision that did not meet the
required statutory and regulatory requirements of the CAA and the RHR,
respectively. In addition, if the EPA finalizes the partial approval
and partial disapproval of the Plan, as proposed in this document, in
the process of correcting the deficiencies outlined above with respect
to the RHR and statutory requirements, the state (or the EPA in the
case of an eventual FIP) will be required to again satisfy the FLM
consultation requirement under 51.308(i). Therefore, we are proposing
to disapprove the Plan with respect to the requirements under 40 CFR
51.308(i) as outlined in this section.

V. Proposed Action

The EPA is proposing to partially approve and partially disapprove
the 2024 Hawaii Regional Haze Plan. Specifically, the EPA is proposing
approval for the portions of Hawaii's 2022 SIP submission relating to
40 CFR 51.308(f)(1): calculations of baseline, current, and natural
visibility conditions, progress to date, and the uniform rate of
progress; 40 CFR 51.308(f)(4): reasonably attributable visibility
impairment; 40 CFR 51.308(f)(5) and 40 CFR 51.308(g): progress report
requirements; and 40 CFR 51.308(f)(6): monitoring strategy and other
implementation plan requirements. The EPA is proposing disapproval of
portions of the 2024 Hawaii Regional Haze Plan relating to 40 CFR
51.308(f)(2): long-term strategy; 40 CFR 51.308(f)(3): reasonable
progress goals; and 40 CFR 51.308(i): FLM consultation.
Under section 179(a) of the CAA, final disapproval of a submittal
that addresses a requirement of part D, title I of the CAA or is
required in response to a finding of substantial inadequacy as
described in CAA section 110(k)(5) (SIP Call) starts a sanctions clock.
The Plan was not submitted to meet any of these requirements.
Therefore, if finalized, this partial disapproval would not trigger any
offset or highway sanctions clocks. Disapproving a SIP submission also
establishes a two-year deadline for the EPA to promulgate a FIP to
address the relevant requirements under CAA section 110(c), unless the
EPA approves a subsequent SIP submission that meets these requirements.

VI. Statutory and Executive Order Reviews

Under the CAA, the Administrator is required to approve a SIP
submission

[[Page 7222]]

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 review state choices, and approve
those choices if they meet the minimum criteria of the Act.
Accordingly, this proposed rulemaking proposes to partially approve and
partially disapprove state law as meeting federal requirements and does
not impose additional requirements beyond those imposed by state law.
Additional information about these statutes and Executive Orders
can be found at <a href="https://www.epa.gov/laws-regulations/laws-and-executive-orders">https://www.epa.gov/laws-regulations/laws-and-executive-orders</a>.

A. Executive Order 12866: Regulatory Planning and Review and Executive
Order 13563: Improving Regulation and Regulatory Review

This action is not a significant regulatory action and was
therefore not submitted to the Office of Management and Budget (OMB)
for review.

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

This action is not expected to be an Executive Order 14192
regulatory action because this action is not significant under
Executive Order 12866.

C. Paperwork Reduction Act (PRA)

This action does not impose an information collection burden under
the PRA because this action does not impose additional requirements
beyond those imposed by state law.

D. Regulatory Flexibility Act (RFA)

I certify that this action will not have a significant economic
impact on a substantial number of small entities under the RFA. This
action will not impose any requirements on small entities beyond those
imposed by state law.

E. Unfunded Mandates Reform Act (UMRA)

This action does not contain any unfunded mandate as described in
UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect
small governments. This action does not impose additional requirements
beyond those imposed by state law. Accordingly, no additional costs to
state, local, or Tribal governments, or to the private sector, will
result from this action.

F. Executive Order 13132: Federalism

This action does not have federalism implications. It will not have
substantial direct effects on the states, on the relationship between
the national government and the states, or on the distribution of power
and responsibilities among the various levels of government.

G. Executive Order 13175: Coordination With Indian Tribal Governments

This action does not have Tribal implications, as specified in
Executive Order 13175, because 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, and will not
impose substantial direct costs on Tribal governments or preempt Tribal
law. Thus, Executive Order 13175 does not apply to this action.

H. Executive Order 13045: Protection of Children From Environmental
Health Risks and Safety Risks

The EPA interprets Executive Order 13045 as applying only to those
regulatory actions that concern environmental health or safety risks
that the EPA has reason to believe may disproportionately affect
children, per the definition of ``covered regulatory action'' in
section 2-202 of the Executive Order. Therefore, this action is not
subject to Executive Order 13045 because it merely proposes to
partially approve and partially disapprove state law as meeting federal
requirements. Furthermore, the EPA's Policy on Children's Health does
not apply to this action.

I. Executive Order 13211: Actions That Significantly Affect Energy
Supply, Distribution, or Use

This action is not subject to Executive Order 13211, because it is
not a significant regulatory action under Executive Order 12866.

J. National Technology Transfer and Advancement Act (NTTAA)

Section 12(d) of the NTTAA directs the EPA to use voluntary
consensus standards in its regulatory activities unless to do so would
be inconsistent with applicable law or otherwise impractical. The EPA
believes that this action is not subject to the requirements of section
12(d) of the NTTAA because application of those requirements would be
inconsistent with the CAA.

List of Subjects in 40 CFR Part 52

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

Dated: February 5, 2026.
Michael Martucci,
Acting Regional Administrator, Region IX.
[FR Doc. 2026-03072 Filed 2-13-26; 8:45 am]
BILLING CODE 6560-50-P

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This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.