[Federal Register Volume 89, Number 139 (Friday, July 19, 2024)]
[Proposed Rules]
[Pages 58663-58685]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-15857]


=======================================================================
-----------------------------------------------------------------------

ENVIRONMENTAL PROTECTION AGENCY

40 CFR Part 52

[EPA-R01-OAR-2023-0186; FRL-12105-01-R1]


Approval and Promulgation of Air Quality Implementation Plans; 
Connecticut; Regional Haze State Implementation Plan for the Second 
Implementation Period

AGENCY: Environmental Protection Agency (EPA).

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: The Environmental Protection Agency (EPA) is proposing to 
approve the regional haze state implementation plan (SIP) revision 
submitted by Connecticut on January 5, 2022, as satisfying applicable 
requirements under the Clean Air Act (CAA) and EPA's Regional Haze Rule 
for the program's second implementation period. Connecticut's SIP 
submission addresses the requirement that states must periodically 
revise their long-term strategies for making reasonable progress 
towards the national goal of preventing any future, and remedying any 
existing, anthropogenic impairment of visibility, including regional 
haze, in mandatory Class I Federal areas. The SIP submission also 
addresses other applicable requirements for the second implementation 
period of the regional haze program. The EPA is taking this action 
pursuant to the CAA.

DATES: Written comments must be received on or before August 19, 2024.

ADDRESSES: Submit your comments, identified by Docket ID No. EPA-R01-
OAR-2023-0186 at https://www.regulations.gov. For comments submitted at 
Regulations.gov, follow the online instructions for submitting 
comments. Once submitted, comments cannot be edited or removed from 
Regulations.gov. 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 https://www.epa.gov/dockets/commenting-epa-dockets.

FOR FURTHER INFORMATION CONTACT: Eric Rackauskas, U.S. Environmental 
Protection Agency, Region 1, Air Quality Branch, 5 Post Office Square, 
Suite 100, (Mail code 5-MI), Boston, MA 02109-3912, telephone number: 
(617) 918-1628, email address: [email protected].

SUPPLEMENTARY INFORMATION: 

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. Identification of Class I Areas
    B. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress
    C. Long-Term Strategy for Regional Haze
    D. Reasonable Progress Goals
    E. Monitoring Strategy and Other State Implementation Plan 
Requirements
    F. Requirements for Periodic Reports Describing Progress Towards 
the Reasonable Progress Goals
    G. Requirements for State and Federal Land Manager Coordination
IV. The EPA's Evaluation of Connecticut's Regional Haze Submission 
for the Second Implementation Period
    A. Background on Connecticut's First Implementation Period SIP 
Submission
    B. Connecticut's Second Implementation Period SIP Submission and 
the EPA's Evaluation
    C. Identification of Class I Areas
    D. Calculations of Baseline, Current, and Natural Visibility 
Conditions; Progress to Date; and the Uniform Rate of Progress
    E. Long-Term Strategy for Regional Haze
    a. Connecticut's Response to the Six MANEVU Asks
    b. The EPA's Evaluation of Connecticut's Response to the Six 
MANEVU Asks and Compliance With Sec.  51.308(f)(2)(i)
    c. Additional Long-Term Strategy Requirements
    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
    J. Other Required Commitments
V. Proposed Action
VI. Statutory and Executive Order Reviews

I. What action is the EPA proposing?

    On January 5, 2022, the Connecticut Department of Energy and 
Environmental Protection (CT DEEP) submitted a revision to its SIP to 
address regional haze for the second implementation period. CT DEEP 
made this SIP submission to satisfy the requirements of the CAA's 
regional haze program pursuant to CAA sections 169A and 169B and 40 CFR 
51.308. The EPA is proposing to find that the Connecticut regional haze 
SIP submission for the second implementation period meets the 
applicable statutory and regulatory requirements and thus proposes to 
approve Connecticut's submission into its SIP.

II. Background and Requirements for Regional Haze Plans

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.\1\ CAA 
section 169A. The CAA establishes as a national goal

[[Page 58664]]

the ``prevention of any future, and the remedying of any existing, 
impairment of visibility in mandatory class I Federal areas which 
impairment results from manmade air pollution.'' CAA section 
169A(a)(1). The CAA further directs the EPA to promulgate regulations 
to assure reasonable progress toward meeting this national goal. CAA 
section 169A(a)(4). On December 2, 1980, the EPA promulgated 
regulations to address visibility impairment in mandatory Class I 
Federal areas (hereinafter referred to as ``Class I areas'') that is 
``reasonably attributable'' to a single source or small group of 
sources. (45 FR 80084, December 2, 1980). These regulations, codified 
at 40 CFR 51.300 through 51.307, represented the first phase of the 
EPA's efforts to address visibility impairment. In 1990, Congress added 
section 169B to the CAA to further address visibility impairment, 
specifically, impairment from regional haze. CAA section 169B. The EPA 
promulgated the Regional Haze Rule (RHR), codified at 40 CFR 51.308,\2\ 
on July 1, 1999. (64 FR 35714, July 1, 1999). These regional haze 
regulations are a central component of the EPA's comprehensive 
visibility protection program for Class I areas.
---------------------------------------------------------------------------

    \1\ Areas statutorily designated as mandatory Class I Federal 
areas consist of national parks exceeding 6,000 acres, wilderness 
areas and national memorial parks exceeding 5,000 acres, and all 
international parks that were in existence on August 7, 1977. CAA 
section 162(a). There are 156 mandatory Class I areas. The list of 
areas to which the requirements of the visibility protection program 
apply is in 40 CFR part 81, subpart D.
    \2\ In addition to the generally applicable regional haze 
provisions at 40 CFR 51.308, the EPA also promulgated regulations 
specific to addressing regional haze visibility impairment in Class 
I areas on the Colorado Plateau at 40 CFR 51.309. The latter 
regulations are applicable only for specific jurisdictions' regional 
haze plans submitted no later than December 17, 2007, and thus are 
not relevant here.
---------------------------------------------------------------------------

    Regional haze is visibility impairment that is produced by a 
multitude of anthropogenic sources and activities which are located 
across a broad geographic area and that emit pollutants that impair 
visibility. Visibility impairing pollutants include fine and coarse 
particulate matter (PM) (e.g., sulfates, nitrates, organic carbon, 
elemental carbon, and soil dust) and their precursors (e.g., sulfur 
dioxide (SO2), nitrogen oxides (NOX), and, in 
some cases, volatile organic compounds (VOC) and ammonia 
(NH3)). Fine particle precursors react in the atmosphere to 
form fine particulate matter (PM2.5), which impairs 
visibility by scattering and absorbing light. Visibility impairment 
reduces the perception of clarity and color, as well as visible 
distance.\3\
---------------------------------------------------------------------------

    \3\ There are several ways to measure the amount of visibility 
impairment, i.e., haze. One such measurement is the deciview, which 
is the principal metric used by the RHR. Under many circumstances, a 
change in one deciview will be perceived by the human eye to be the 
same on both clear and hazy days. The deciview is unitless. It is 
proportional to the logarithm of the atmospheric extinction of 
light, which is the perceived dimming of light due to its being 
scattered and absorbed as it passes through the atmosphere. 
Atmospheric light extinction (b\ext\) is a metric used to for 
expressing visibility and is measured in inverse megameters (Mm-1). 
The EPA's Guidance on Regional Haze State Implementation Plans for 
the Second Implementation Period (``2019 Guidance'') offers the 
flexibility for the use of light extinction in certain cases. Light 
extinction can be simpler to use in calculations than deciviews, 
since it is not a logarithmic function. See, e.g., 2019 Guidance at 
16, 19, https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period, The EPA Office of 
Air Quality Planning and Standards, Research Triangle Park (August 
20, 2019). The formula for the deciview is 10 ln (b\ext\)/10 Mm-1). 
40 CFR 51.301.
---------------------------------------------------------------------------

    To address regional haze visibility impairment, the 1999 RHR 
established an iterative planning process that requires both states in 
which Class I areas are located and states ``the emissions from which 
may reasonably be anticipated to cause or contribute to any impairment 
of visibility'' in a Class I area to periodically submit SIP revisions 
to address such impairment. CAA section 169A(b)(2); \4\ see also 40 CFR 
51.308(b), (f) (establishing submission dates for iterative regional 
haze SIP revisions); (64 FR at 35768, July 1, 1999). Under the CAA, 
each SIP submission must contain ``a long-term (ten to fifteen years) 
strategy for making reasonable progress toward meeting the national 
goal,'' CAA section 169A(b)(2)(B); the initial round of SIP submissions 
also had to address the statutory requirement that certain older, 
larger sources of visibility impairing pollutants install and operate 
the best available retrofit technology (BART). CAA section 
169A(b)(2)(A); 40 CFR 51.308(d), (e). States' first regional haze SIPs 
were due by December 17, 2007, 40 CFR 51.308(b), with subsequent SIP 
submissions containing updated long-term strategies originally due July 
31, 2018, and every ten years thereafter. (64 FR at 35768, July 1, 
1999). The EPA established in the 1999 RHR that all states either have 
Class I areas within their borders or ``contain sources whose emissions 
are reasonably anticipated to contribute to regional haze in a Class I 
area''; therefore, all states must submit regional haze SIPs.\5\ Id. at 
35721.
---------------------------------------------------------------------------

    \4\ 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).
    \5\ In addition to each of the fifty states, the EPA also 
concluded that the Virgin Islands and District of Columbia must also 
submit regional haze SIPs because they either contain a Class I area 
or contain sources whose emissions are reasonably anticipated to 
contribute regional haze in a Class I area. See 40 CFR 51.300(b), 
(d)(3).
---------------------------------------------------------------------------

    Much of the focus in the first implementation period of the 
regional haze program, which ran from 2007 through 2018, was on 
satisfying states' BART obligations. First implementation period SIPs 
were additionally required to contain long-term strategies for making 
reasonable progress toward the national visibility goal, of which BART 
is one component. The core required elements for the first 
implementation period SIPs (other than BART) are laid out in 40 CFR 
51.308(d). Those provisions required that states containing Class I 
areas establish reasonable progress goals (RPGs) that are measured in 
deciviews and reflect the anticipated visibility conditions at the end 
of the implementation period including from implementation of states' 
long-term strategies. The first planning period RPGs were required to 
provide for an improvement in visibility for the most impaired days 
over the period of the implementation plan and ensure no degradation in 
visibility for the least impaired days over the same period. In 
establishing the RPGs for any Class I area in a state, the state was 
required to consider four statutory factors: the costs of compliance, 
the time necessary for compliance, the energy and non-air quality 
environmental impacts of compliance, and the remaining useful life of 
any potentially affected sources. CAA section 169A(g)(1); 40 CFR 
51.308(d)(1).
    States were also required to calculate baseline (using the five-
year period of 2000-2004) and natural visibility conditions (i.e., 
visibility conditions without anthropogenic visibility impairment) for 
each Class I area, and to calculate 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 known as the uniform 
rate of progress (URP) and 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.\6\ 40 CFR 
51.308(d)(1)(i)(B), (d)(2).

[[Page 58665]]

The 1999 RHR also provided that States' long-term strategies must 
include the ``enforceable emissions limitations, compliance, schedules, 
and other measures as necessary to achieve the reasonable progress 
goals.'' 40 CFR 51.308(d)(3). In establishing their long-term 
strategies, states are required to consult with other states that also 
contribute to visibility impairment in a given Class I area and include 
all measures necessary to obtain their shares of the emission 
reductions needed to meet the RPGs. 40 CFR 51.308(d)(3)(i), (ii). 
Section 51.308(d) also contains seven additional factors states must 
consider in formulating their long-term strategies, 40 CFR 
51.308(d)(3)(v), as well as provisions governing monitoring and other 
implementation plan requirements. 40 CFR 51.308(d)(4). Finally, the 
1999 RHR required states to submit periodic progress reports--SIP 
revisions due every five years that contain information on states' 
implementation of their regional haze plans and an assessment of 
whether anything additional is needed to make reasonable progress, see 
40 CFR 51.308(g), (h)--and to consult with the Federal Land Manager(s) 
\7\ (FLMs) responsible for each Class I area according to the 
requirements in CAA section 169A(d) and 40 CFR 51.308(i).
---------------------------------------------------------------------------

    \6\ EPA established the URP framework in the 1999 RHR to provide 
``an equitable analytical approach'' to assessing the rate of 
visibility improvement at Class I areas across the country. The 
start point for the URP analysis is 2004 and the endpoint was 
calculated based on the amount of visibility improvement that was 
anticipated to result from implementation of existing CAA programs 
over the period from the mid-1990s to approximately 2005. Assuming 
this rate of progress would continue into the future, EPA determined 
that natural visibility conditions would be reached in 60 years, or 
2064 (60 years from the baseline starting point of 2004). However, 
EPA did not establish 2064 as the year by which the national goal 
must be reached. 64 FR at 35731-32. That is, the URP and the 2064 
date are not enforceable targets, but are rather tools that ``allow 
for analytical comparisons between the rate of progress that would 
be achieved by the state's chosen set of control measures and the 
URP.'' (82 FR 3078, 3084, January 10, 2017).
    \7\ The EPA's regulations define ``Federal Land Manager'' as 
``the Secretary of the department with authority over the Federal 
Class I area (or the Secretary designee) or, with respect to 
Roosevelt-Campobello International Park, the Chairman of the 
Roosevelt-Campobello International Park Commission.'' 40 CFR 51.301.
---------------------------------------------------------------------------

    On January 10, 2017, the EPA promulgated revisions to the RHR, (82 
FR 3078, January 10, 2017), that apply for the second and subsequent 
implementation periods. The 2017 rulemaking made several changes to the 
requirements for regional haze SIPs to clarify States' obligations and 
streamline certain regional haze requirements. The revisions to the 
regional haze program for the second and subsequent implementation 
periods focused on the requirement that States' SIPs contain long-term 
strategies for making reasonable progress towards the national 
visibility goal. 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). Among other changes, the 2017 RHR 
Revisions adjusted the deadline for States to submit their second 
implementation period SIPs from July 31, 2018, to July 31, 2021, 
clarified the order of analysis and the relationship between RPGs and 
the long-term strategy, and focused on making visibility improvements 
on the days with the most anthropogenic visibility impairment, as 
opposed to the days with the most visibility impairment overall. The 
EPA also revised requirements of the visibility protection program 
related to periodic progress reports and FLM consultation. The specific 
requirements applicable to second implementation period regional haze 
SIP submissions are addressed in detail below.
    The EPA provided guidance to the states for their second 
implementation period SIP submissions in the preamble to the 2017 RHR 
Revisions as well as in subsequent, stand-alone guidance documents. In 
August 2019, the EPA issued ``Guidance on Regional Haze State 
Implementation Plans for the Second Implementation Period'' (``2019 
Guidance'').\8\ On July 8, 2021, the EPA issued a memorandum containing 
``Clarifications Regarding Regional Haze State Implementation Plans for 
the Second Implementation Period'' (``2021 Clarifications Memo'').\9\ 
Additionally, the EPA further clarified the recommended procedures for 
processing ambient visibility data and optionally adjusting the URP to 
account for international anthropogenic and prescribed fire impacts in 
two technical guidance documents: the December 2018 ``Technical 
Guidance on Tracking Visibility Progress for the Second Implementation 
Period of the Regional Haze Program'' (``2018 Visibility Tracking 
Guidance''),\10\ 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 (``2020 
Data Completeness Memo'').\11\
---------------------------------------------------------------------------

    \8\ Guidance on Regional Haze State Implementation Plans for the 
Second Implementation Period. https://www.epa.gov/visibility/guidance-regional-haze-state-implementation-plans-second-implementation-period. The EPA Office of Air Quality Planning and 
Standards, Research Triangle Park (August 20, 2019).
    \9\ Clarifications Regarding Regional Haze State Implementation 
Plans for the Second Implementation Period. https://www.epa.gov/system/files/documents/2021-07/clarifications-regarding-regional-haze-state-implementation-plans-for-the-second-implementation-period.pdf. The EPA Office of Air Quality Planning and Standards, 
Research Triangle Park (July 8, 2021).
    \10\ Technical Guidance on Tracking Visibility Progress for the 
Second Implementation Period of the Regional Haze Program. https://www.epa.gov/visibility/technical-guidance-tracking-visibility-progress-second-implementation-period-regional. The EPA Office of 
Air Quality Planning and Standards, Research Triangle Park. 
(December 20, 2018).
    \11\ 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. https://www.epa.gov/visibility/memo-and-technical-addendum-ambient-data-usage-and-completeness-regional-haze-program. The EPA 
Office of Air Quality Planning and Standards, Research Triangle Park 
(June 3, 2020).
---------------------------------------------------------------------------

    As previously explained in the 2021 Clarifications Memo, EPA 
intends the second implementation period of the regional haze program 
to secure meaningful reductions in visibility impairing pollutants that 
build on the significant progress states have achieved to date. The 
Agency also recognizes that analyses regarding reasonable progress are 
state-specific and that, based on states' and sources' individual 
circumstances, what constitutes reasonable reductions in visibility 
impairing pollutants will vary from state-to-state. While there exist 
many opportunities for states to leverage both ongoing and upcoming 
emission reductions under other CAA programs, the Agency expects states 
to undertake rigorous reasonable progress analyses that identify 
further opportunities to advance the national visibility goal 
consistent with the statutory and regulatory requirements. See 
generally 2021 Clarifications Memo. This is consistent with Congress's 
determination that a visibility protection program is needed in 
addition to the CAA's National Ambient Air Quality Standards and 
Prevention of Significant Deterioration programs, as further emission 
reductions may be necessary to adequately protect visibility in Class I 
areas throughout the country.\12\
---------------------------------------------------------------------------

    \12\ See, e.g., H.R. Rep No. 95-294 at 205 (``In determining how 
to best remedy the growing visibility problem in these areas of 
great scenic importance, the committee realizes that as a matter of 
equity, the national ambient air quality standards cannot be revised 
to adequately protect visibility in all areas of the country.''), 
(``the mandatory class I increments of [the PSD program] do not 
adequately protect visibility in class I areas'').
---------------------------------------------------------------------------

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. In order to address regional haze, states 
need to develop strategies in coordination with one another, 
considering the effect of emissions from

[[Page 58666]]

one jurisdiction on the air quality in another. Five regional planning 
organizations (RPOs),\13\ which include representation from state and 
tribal governments, the EPA, and FLMs, were developed in the lead-up to 
the first implementation period to address regional haze. RPOs evaluate 
technical information to better understand how emissions from State and 
Tribal land impact Class I areas across the country, pursue the 
development of regional strategies to reduce emissions of particulate 
matter and other pollutants leading to regional haze, and help states 
meet the consultation requirements of the RHR.
---------------------------------------------------------------------------

    \13\ RPOs are sometimes also referred to as ``multi-
jurisdictional organizations,'' or MJOs. For the purposes of this 
document, the terms RPO and MJO are synonymous.
---------------------------------------------------------------------------

    The Mid-Atlantic/Northeast Visibility Union (MANEVU), 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 Mid-Atlantic and Northeast corridor of the United States. Member 
states and tribal governments (listed alphabetically) include: 
Connecticut, Delaware, the District of Columbia, Maine, Maryland, 
Massachusetts, New Hampshire, New Jersey, New York, Pennsylvania, 
Penobscot Indian Nation, Rhode Island, St. Regis Mohawk Tribe, and 
Vermont. The Federal partner members of MANEVU are EPA, U.S. National 
Parks Service (NPS), U.S. Fish and Wildlife Service (FWS), and U.S. 
Forest Service (USFS).

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

    Under the CAA and EPA's regulations, all 50 states, the District of 
Columbia, and the U.S. Virgin Islands are required to submit regional 
haze SIPs satisfying the applicable requirements for the second 
implementation period of the regional haze program by July 31, 2021. 
Each state's SIP must contain a long-term strategy for making 
reasonable progress toward meeting the national goal of remedying any 
existing and preventing any future anthropogenic visibility impairment 
in Class I areas. CAA section 169A(b)(2)(B). To this end, Sec.  
51.308(f) lays out the process by which states determine what 
constitutes their long-term strategies, with the order of the 
requirements in Sec.  51.308(f)(1) through (f)(3) generally mirroring 
the order of the steps in the reasonable progress analysis \14\ 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. 
See 40 CFR 51.308(f), (f)(2). For each Class I area within its borders, 
a state must then calculate the baseline, current, and natural 
visibility conditions for that area, as well as the visibility 
improvement made to date and the URP. See 40 CFR 51.308(f)(1). Each 
state having a Class I area and/or emissions that may affect visibility 
in a Class I area must then develop a long-term strategy that includes 
the enforceable emission limitations, compliance schedules, and other 
measures that are necessary to make reasonable progress in such areas. 
A reasonable progress determination is based on applying the four 
factors in CAA section 169A(g)(1) to sources of visibility-impairing 
pollutants that the state has selected to assess for controls for the 
second implementation period. See 40 CFR 51.308(f)(2). Additionally, as 
further explained below, the RHR at 40 CFR 51.308(f)(2)(iv) separately 
provides five ``additional factors'' \15\ that states must consider in 
developing their long-term strategies. A state evaluates potential 
emission reduction measures for those selected sources and determines 
which are necessary to make reasonable progress. Those measures are 
then incorporated into the state's long-term strategy. After a state 
has developed its long-term strategy, it then establishes RPGs for each 
Class I area within its borders by modeling the visibility impacts of 
all reasonable progress controls at the end of the second 
implementation period, i.e., in 2028, as well as the impacts of other 
requirements of the CAA. The RPGs include reasonable progress controls 
not only for sources in the state in which the Class I area is located, 
but also for sources in other states that contribute to visibility 
impairment in that area. The RPGs are then compared to the baseline 
visibility conditions and the URP to ensure that progress is being made 
towards the statutory goal of preventing any future and remedying any 
existing anthropogenic visibility impairment in Class I areas. 40 CFR 
51.308(f)(2)-(3).
---------------------------------------------------------------------------

    \14\ EPA explained in the 2017 RHR Revisions that we were 
adopting new regulatory language in 40 CFR 51.308(f) that, unlike 
the structure in 51.308(d), ``tracked the actual planning 
sequence.'' (82 FR 3091, January 10, 2017).
    \15\ The five ``additional factors'' for consideration in Sec.  
51.308(f)(2)(iv) are distinct from the four factors listed in CAA 
section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states must 
consider and apply to sources in determining reasonable progress.
---------------------------------------------------------------------------

    In addition to satisfying the requirements at 40 CFR 51.308(f) 
related to reasonable progress, the regional haze SIP revisions for the 
second implementation period must address the requirements in Sec.  
51.308(g)(1) through (5) pertaining to periodic reports describing 
progress towards the RPGs, 40 CFR 51.308(f)(5), as well as requirements 
for FLM consultation that apply to all visibility protection SIPs and 
SIP revisions. 40 CFR 51.308(i).
    A state must submit its regional haze SIP and subsequent SIP 
revisions to the EPA according to the requirements applicable to all 
SIP revisions under the CAA and EPA's regulations. See CAA section 
169(b)(2); CAA section 110(a). Upon EPA approval, a SIP is enforceable 
by the Agency and the public under the CAA. If EPA finds that a state 
fails to make a required SIP revision, or if the EPA finds that a 
state's SIP is incomplete or if disapproves the SIP, the Agency must 
promulgate a federal implementation plan (FIP) that satisfies the 
applicable requirements. CAA section 110(c)(1).

A. Identification of Class I Areas

    The first step in developing a regional haze SIP is for a state to 
determine which Class I areas, in addition to those within its borders, 
``may be affected'' by emissions from within the state. In the 1999 
RHR, the EPA determined that all states contribute to visibility 
impairment in at least one Class I area, 64 FR at 35720-22, and 
explained that the statute and regulations lay out an ``extremely low 
triggering threshold'' for determining ``whether States should be 
required to engage in air quality planning and analysis as a 
prerequisite to determining the need for control of emissions from 
sources within their State.'' Id. at 35721.
    A state must determine which Class I areas must be addressed by its 
SIP by evaluating the total emissions of visibility impairing 
pollutants from all sources within the state. While the RHR does not 
require this evaluation to be conducted in any particular manner, EPA's 
2019 Guidance provides recommendations for how such an assessment might 
be accomplished, including by, where appropriate, using the 
determinations previously made for the first implementation period. 
2019 Guidance at 8-9. In addition, the determination of which Class I 
areas may be affected by a state's emissions is subject to the 
requirement in 40 CFR 51.308(f)(2)(iii) to ``document the

[[Page 58667]]

technical basis, including modeling, monitoring, cost, engineering, and 
emissions information, on which the State is relying to determine the 
emission reduction measures that are necessary to make reasonable 
progress in each mandatory Class I Federal area it affects.''

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

    As part of assessing whether a SIP submission for the second 
implementation period is providing for reasonable progress towards the 
national visibility goal, the RHR contains requirements in Sec.  
51.308(f)(1) related to tracking visibility improvement over time. The 
requirements of this subsection apply only to states having Class I 
areas within their borders; the required calculations must be made for 
each such Class I area. EPA's 2018 Visibility Tracking Guidance \16\ 
provides recommendations to assist states in satisfying their 
obligations under Sec.  51.308(f)(1)--specifically, in developing 
information on baseline, current, and natural visibility conditions, 
and in making optional adjustments to the URP to account for the 
impacts of international anthropogenic emissions and prescribed fires. 
See 82 FR at 3103-05.
---------------------------------------------------------------------------

    \16\ The 2018 Visibility Tracking Guidance references and relies 
on parts of the 2003 Tracking Guidance: ``Guidance for Tracking 
Progress Under the Regional Haze Rule,'' which can be found at 
https://www3.epa.gov/ttnamti1/files/ambient/visible/tracking.pdf.
---------------------------------------------------------------------------

    The RHR requires tracking of visibility conditions on two sets of 
days: the clearest and the most impaired days. Visibility conditions 
for both sets of days are expressed as the average deciview index for 
the relevant five-year period (the period representing baseline or 
current visibility conditions). The RHR provides that the relevant sets 
of days for visibility tracking purposes are the 20% clearest (the 20% 
of monitored days in a calendar year with the lowest values of the 
deciview index) and 20% most impaired days (the 20% of monitored days 
in a calendar year with the highest amounts of anthropogenic visibility 
impairment).\17\ 40 CFR 51.301. A state must calculate visibility 
conditions for both the 20% clearest and 20% most impaired days for the 
baseline period of 2000-2004 and the most recent five-year period for 
which visibility monitoring data are available (representing current 
visibility conditions). 40 CFR 51.308(f)(1)(i), (iii). States must also 
calculate natural visibility conditions for the clearest and most 
impaired days,\18\ by estimating the conditions that would exist on 
those two sets of days absent anthropogenic visibility impairment. 40 
CFR 51.308(f)(1)(ii). Using all these data, states must then calculate, 
for each Class I area, the amount of progress made since the baseline 
period (2000-2004) and how much improvement is left to achieve in order 
to reach natural visibility conditions.
---------------------------------------------------------------------------

    \17\ This document also refers to the 20% clearest and 20% most 
anthropogenically impaired days as the ``clearest'' and ``most 
impaired'' or ``most anthropogenically impaired'' days, 
respectively.
    \18\ The RHR at 40 CFR 51.308(f)(1)(ii) contains an error 
related to the requirement for calculating two sets of natural 
conditions values. The rule says ``most impaired days or the 
clearest days'' where it should say ``most impaired days and 
clearest days.'' This is an error that was intended to be corrected 
in the 2017 RHR Revisions but did not get corrected in the final 
rule language. This is supported by the preamble text at 82 FR 3098: 
``In the final version of 40 CFR 51.308(f)(1)(ii), an occurrence of 
``or'' has been corrected to ``and'' to indicate that natural 
visibility conditions for both the most impaired days and the 
clearest days must be based on available monitoring information.''
---------------------------------------------------------------------------

    Using the data for the set of most impaired days only, states must 
plot a line between visibility conditions in the baseline period and 
natural visibility conditions for each Class I area to determine the 
URP--the amount of visibility improvement per year, measured in 
deciviews, that would need to be achieved during each implementation 
period in order to achieve natural visibility conditions by the end of 
2064. The URP is used in later steps of the reasonable progress 
analysis for informational purposes and to provide a non-enforceable 
benchmark against which to assess a Class I area's rate of visibility 
improvement.\19\ Additionally, in the 2017 RHR Revisions, the EPA 
provided states the option of proposing to adjust the endpoint of the 
URP to account for impacts of anthropogenic sources outside the United 
States and/or impacts of certain types of wildland prescribed fires. 
These adjustments, which must be approved by the EPA, are intended to 
avoid any perception that states should compensate for impacts from 
international anthropogenic sources and to give states the flexibility 
to determine that limiting the use of wildland-prescribed fire is not 
necessary for reasonable progress. 82 FR 3107 footnote 116.
---------------------------------------------------------------------------

    \19\ Being on or below the URP is not a ``safe harbor''; i.e., 
achieving the URP does not mean that a Class I area is making 
``reasonable progress'' and does not relieve a state from using the 
four statutory factors to determine what level of control is needed 
to achieve such progress. See, e.g., 82 FR at 3093.
---------------------------------------------------------------------------

    EPA's 2018 Visibility Tracking Guidance can be used to help satisfy 
the 40 CFR 51.308(f)(1) requirements, including in developing 
information on baseline, current, and natural visibility conditions, 
and in making optional adjustments to the URP. In addition, the 2020 
Data Completeness Memo provides recommendations on the data 
completeness language referenced in Sec.  51.308(f)(1)(i) and provides 
updated natural conditions estimates for each Class I area.

C. Long-Term Strategy for Regional Haze

    The core component of a regional haze SIP submission is a long-term 
strategy that addresses regional haze in each Class I area within a 
state's borders and each Class I area that may be affected by emissions 
from the state. The long-term strategy ``must include the enforceable 
emissions limitations, compliance schedules, and other measures that 
are necessary to make reasonable progress, as determined pursuant to 
(f)(2)(i) through (iv).'' 40 CFR 51.308(f)(2). The amount of progress 
that is ``reasonable progress'' is based on applying the four statutory 
factors in CAA section 169A(g)(1) in an evaluation of potential control 
options for sources of visibility impairing pollutants, which is 
referred to as a ``four-factor'' analysis. The outcome of that analysis 
is the emission reduction measures that a particular source or group of 
sources needs to implement in order to make reasonable progress towards 
the national visibility goal. See 40 CFR 51.308(f)(2)(i). Emission 
reduction measures that are necessary to make reasonable progress may 
be either new, additional control measures for a source, or they may be 
the existing emission reduction measures that a source is already 
implementing. See 2019 Guidance at 43; 2021 Clarifications Memo at 8-
10. Such measures must be represented by ``enforceable emissions 
limitations, compliance schedules, and other measures'' (i.e., any 
additional compliance tools) in a state's long-term strategy in its 
SIP. 40 CFR 51.308(f)(2).
    Section 51.308(f)(2)(i) provides the requirements for the four-
factor analysis. The first step of this analysis entails selecting the 
sources to be evaluated for emission reduction measures; to this end, 
the RHR requires states to consider ``major and minor stationary 
sources or groups of sources, mobile sources, and area sources'' of 
visibility impairing pollutants for potential four-factor control 
analysis. 40 CFR 51.308(f)(2)(i). A threshold question at this step is 
which visibility impairing pollutants will be analyzed. As EPA 
previously explained, consistent with the first implementation period, 
EPA generally expects that each

[[Page 58668]]

state will analyze at least SO2 and NOX in 
selecting sources and determining control measures. See 2019 Guidance 
at 12, 2021 Clarifications Memo at 4. A state that chooses not to 
consider at least these two pollutants should demonstrate why such 
consideration would be unreasonable. 2021 Clarifications Memo at 4.
    While states have the option to analyze all sources, the 2019 
Guidance explains that ``an analysis of control measures is not 
required for every source in each implementation period,'' and that 
``[s]electing a set of sources for analysis of control measures in each 
implementation period is . . . consistent with the Regional Haze Rule, 
which sets up an iterative planning process and anticipates that a 
state may not need to analyze control measures for all its sources in a 
given SIP revision.'' 2019 Guidance at 9. However, given that source 
selection is the basis of all subsequent control determinations, a 
reasonable source selection process ``should be designed and conducted 
to ensure that source selection results in a set of pollutants and 
sources the evaluation of which has the potential to meaningfully 
reduce their contributions to visibility impairment.'' 2021 
Clarifications Memo at 3.
    EPA explained in the 2021 Clarifications Memo that each state has 
an obligation to submit a long-term strategy that addresses the 
regional haze visibility impairment that results from emissions from 
within that state. Thus, source selection should focus on the in-state 
contribution to visibility impairment and be designed to capture a 
meaningful portion of the state's total contribution to visibility 
impairment in Class I areas. A state should not decline to select its 
largest in-state sources on the basis that there are even larger out-
of-state contributors. 2021 Clarifications Memo at 4.\20\
---------------------------------------------------------------------------

    \20\ Similarly, in responding to comments on the 2017 RHR 
Revisions EPA explained that ``[a] state should not fail to address 
its many relatively low-impact sources merely because it only has 
such sources and another state has even more low-impact sources and/
or some high impact sources.'' Responses to Comments on Protection 
of Visibility: Amendments to Requirements for State Plans; Proposed 
Rule (81 FR 26942, May 4, 2016) at 87-88.
---------------------------------------------------------------------------

    Thus, 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.\21\ This is accomplished by considering the four factors--``the 
costs of compliance, the time necessary for compliance, and the energy 
and non-air quality environmental impacts of compliance, and the 
remaining useful life of any existing source subject to such 
requirements.'' CAA section 169A(g)(1). 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 CAA section 
169A(g)(1) strongly indicates that Congress intended the relevant 
determination to be the requirements with which sources would have to 
comply in order to satisfy the CAA's reasonable progress mandate.'' 82 
FR at 3091. Thus, for each source it has selected for four-factor 
analysis,\22\ a state must consider a ``meaningful set'' of technically 
feasible control options for reducing emissions of visibility impairing 
pollutants. Id. at 3088. The 2019 Guidance provides that ``[a] state 
must reasonably pick and justify the measures that it will consider, 
recognizing that there is no statutory or regulatory requirement to 
consider all technically feasible measures or any particular measures. 
A range of technically feasible measures available to reduce emissions 
would be one way to justify a reasonable set.'' 2019 Guidance at 29.
---------------------------------------------------------------------------

    \21\ The CAA provides that, ``[i]n determining reasonable 
progress there shall be taken into consideration'' the four 
statutory factors. CAA section 169A(g)(1). However, in addition to 
four-factor analyses for selected sources, groups of sources, or 
source categories, a state may also consider additional emission 
reduction measures for inclusion in its long-term strategy, e.g., 
from other newly adopted, on-the-books, or on-the-way rules and 
measures for sources not selected for four-factor analysis for the 
second planning period.
    \22\ ``Each source'' or ``particular source'' is used here as 
shorthand. While a source-specific analysis is one way of applying 
the four factors, neither the statute nor the RHR requires states to 
evaluate individual sources. Rather, states have ``the flexibility 
to conduct four-factor analyses for specific sources, groups of 
sources or even entire source categories, depending on state policy 
preferences and the specific circumstances of each state.'' 82 FR at 
3088. However, not all approaches to grouping sources for four-
factor analysis are necessarily reasonable; the reasonableness of 
grouping sources in any particular instance will depend on the 
circumstances and the manner in which grouping is conducted. If it 
is feasible to establish and enforce different requirements for 
sources or subgroups of sources, and if relevant factors can be 
quantified for those sources or subgroups, then states should make a 
separate reasonable progress determination for each source or 
subgroup. 2021 Clarifications Memo at 7-8.
---------------------------------------------------------------------------

    EPA's 2021 Clarifications Memo provides further guidance on what 
constitutes a reasonable set of control options for consideration: ``A 
reasonable four-factor analysis will consider the full range of 
potentially reasonable options for reducing emissions.'' 2021 
Clarifications Memo at 7. In addition to add-on controls and other 
retrofits (i.e., new emission reduction measures for sources), EPA 
explained that states should generally analyze efficiency improvements 
for sources' existing measures as control options in their four-factor 
analyses, as in many cases such improvements are reasonable given that 
they typically involve only additional operation and maintenance costs. 
Additionally, the 2021 Clarifications Memo provides that states that 
have assumed a higher emission rate than a source has achieved or could 
potentially achieve using its existing measures should also consider 
lower emission rates as potential control options. That is, a state 
should consider a source's recent actual and projected emission rates 
to determine if it could reasonably attain lower emission rates with 
its existing measures. If so, the state should analyze the lower 
emission rate as a control option for reducing emissions. 2021 
Clarifications Memo at 7. The EPA's recommendations to analyze 
potential efficiency improvements and achievable lower emission rates 
apply to both sources that have been selected for four-factor analysis 
and those that have forgone a four-factor analysis on the basis of 
existing ``effective controls.'' See 2021 Clarifications Memo at 5, 10.
    After identifying a reasonable set of potential control options for 
the sources it has selected, a state then collects information on the 
four factors with regard to each option identified. 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.\23\ The 2019 Guidance provides recommendations for the types 
of information that can be used to

[[Page 58669]]

characterize the four factors (with or without visibility), as well as 
ways in which states might reasonably consider and balance that 
information to determine which of the potential control options is 
necessary to make reasonable progress. See 2019 Guidance at 30-36. The 
2021 Clarifications Memo contains further guidance on how states can 
reasonably consider modeled visibility impacts or benefits in the 
context of a four-factor analysis. 2021 Clarifications Memo at 12-13, 
14-15. Specifically, EPA explained that while visibility can reasonably 
be used when comparing and choosing between multiple reasonable control 
options, it should not be used to summarily reject controls that are 
reasonable given the four statutory factors. 2021 Clarifications Memo 
at 13. Ultimately, while states have discretion to reasonably weigh the 
factors and to determine what level of control is needed, Sec.  
51.308(f)(2)(i) provides that a state ``must include in its 
implementation plan a description of . . . how the four factors were 
taken into consideration in selecting the measure for inclusion in its 
long-term strategy.''
---------------------------------------------------------------------------

    \23\ See, e.g., Responses to Comments on Protection of 
Visibility: Amendments to Requirements for State Plans; Proposed 
Rule (81 FR 26942, May 4, 2016), Docket Number EPA-HQ-OAR-2015-0531, 
U.S. Environmental Protection Agency at 186; 2019 Guidance at 36-37.
---------------------------------------------------------------------------

    As explained above, Sec.  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 Sec.  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.\24\ If the 
outcome of a four-factor analysis is a new, additional emission 
reduction measure for a source, that new measure is necessary to make 
reasonable progress towards remedying existing anthropogenic visibility 
impairment and must be included in the SIP. If the outcome of a four-
factor analysis is that no new measures are reasonable for a source, 
continued implementation of the source's existing measures is generally 
necessary to prevent future emission increases and thus to make 
reasonable progress towards the second part of the national visibility 
goal: preventing future anthropogenic visibility impairment. See CAA 
section 169A(a)(1). That is, when the result of a four-factor analysis 
is that no new measures are necessary to make reasonable progress, the 
source's existing measures are generally necessary to make reasonable 
progress and must be included in the SIP. However, there may be 
circumstances in which a state can demonstrate that a source's existing 
measures are not necessary to make reasonable progress. Specifically, 
if a state can demonstrate that a source will continue to implement its 
existing measures and will not increase its emission rate, it may not 
be necessary to have those measures in the long-term strategy in order 
to prevent future emission increases and future visibility impairment. 
EPA's 2021 Clarifications Memo provides further explanation and 
guidance on how states may demonstrate that a source's existing 
measures are not necessary to make reasonable progress. See 2021 
Clarifications Memo at 8-10. If the state can make such a 
demonstration, it need not include a source's existing measures in the 
long-term strategy or its SIP.
---------------------------------------------------------------------------

    \24\ States may choose to, but are not required to, include 
measures in their long-term strategies beyond just the emission 
reduction measures that are necessary for reasonable progress. See 
2021 Clarifications Memo at 16. For example, states with smoke 
management programs may choose to submit their smoke management 
plans to EPA for inclusion in their SIPs but are not required to do 
so. See, e.g., 82 FR at 3108-09 (requirement to consider smoke 
management practices and smoke management programs under 40 CFR 
51.308(f)(2)(iv) does not require states to adopt such practices or 
programs into their SIPs, although they may elect to do so).
---------------------------------------------------------------------------

    As with source selection, the characterization of information on 
each of the factors is also subject to the documentation requirement in 
Sec.  51.308(f)(2)(iii). The reasonable progress analysis, including 
source selection, information gathering, characterization of the four 
statutory factors (and potentially visibility), balancing of the four 
factors, and selection of the emission reduction measures that 
represent reasonable progress, is a technically complex exercise, but 
also a flexible one that provides states with bounded discretion to 
design and implement approaches appropriate to their circumstances. 
Given this flexibility, Sec.  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. This documentation requirement can be met through 
the provision of and reliance on technical analyses developed through a 
regional planning process, so long as that process and its output has 
been approved by all state participants. In addition to the explicit 
regulatory requirement to document the technical basis of their 
reasonable progress determinations, states are also subject to the 
general principle that those determinations must be reasonably moored 
to the statute.\25\ That is, a state's decisions about the emission 
reduction measures that are necessary to make reasonable progress must 
be consistent with the statutory goal of remedying existing and 
preventing future visibility impairment.
---------------------------------------------------------------------------

    \25\ See Arizona ex rel. Darwin v. U.S. EPA, 815 F.3d 519, 531 
(9th Cir. 2016); Nebraska v. U.S. EPA, 812 F.3d 662, 668 (8th Cir. 
2016); North Dakota v. EPA, 730 F.3d 750, 761 (8th Cir. 2013); 
Oklahoma v. EPA, 723 F.3d 1201, 1206, 1208-10 (10th Cir. 2013); cf. 
also Alaska Dep't of Envtl. Conservation v. EPA, 540 U.S. 461, 485, 
490 (2004); Nat'l Parks Conservation Ass'n v. EPA, 803 F.3d 151, 165 
(3d Cir. 2015).
---------------------------------------------------------------------------

    The four statutory factors (and potentially visibility) are used to 
determine what emission reduction measures for selected sources must be 
included in a state's long-term strategy for making 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. The 2019 Guidance provides that a state may satisfy 
this requirement by considering these additional factors in the process 
of selecting sources for four-factor analysis, when performing that 
analysis, or both, and that not every one of the additional factors 
needs to be considered at the same stage of the process. See 2019 
Guidance at 21. EPA provided further guidance on the five additional 
factors in the 2021 Clarifications Memo, explaining that a state should 
generally not reject cost-effective and otherwise reasonable controls 
merely because there have been emission reductions since the first 
planning period owing to other ongoing air pollution control programs 
or merely

[[Page 58670]]

because visibility is otherwise projected to improve at Class I areas. 
Additionally, states generally should not rely on these additional 
factors to summarily assert that the state has already made sufficient 
progress and, therefore, no sources need to be selected or no new 
controls are needed regardless of the outcome of four-factor analyses. 
2021 Clarifications Memo at 13.
---------------------------------------------------------------------------

    \26\ The five ``additional factors'' for consideration in Sec.  
51.308(f)(2)(iv) are distinct from the four factors listed in CAA 
section 169A(g)(1) and 40 CFR 51.308(f)(2)(i) that states must 
consider and apply to sources in determining reasonable progress.
---------------------------------------------------------------------------

    Because the air pollution that causes regional haze crosses state 
boundaries, Sec.  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. 
Consultation allows for each state that impacts visibility in an area 
to share whatever technical information, analyses, and control 
determinations may be necessary to develop coordinated emission 
management strategies. This coordination may be managed through inter- 
and intra-RPO consultation and the development of regional emissions 
strategies; additional consultations between states outside of RPO 
processes may also occur. If a state, pursuant to consultation, agrees 
that certain measures (e.g., a certain emission limitation) are 
necessary to make reasonable progress at a Class I area, it must 
include those measures in its SIP. 40 CFR 51.308(f)(2)(ii)(A). 
Additionally, the RHR requires that states that contribute to 
visibility impairment at the same Class I area consider the emission 
reduction measures the other contributing states have identified as 
being necessary to make reasonable progress for their own sources. 40 
CFR 51.308(f)(2)(ii)(B). If a state has been asked to consider or adopt 
certain emission reduction measures, but ultimately determines those 
measures are not necessary to make reasonable progress, that state must 
document in its SIP the actions taken to resolve the disagreement. 40 
CFR 51.308(f)(2)(ii)(C). The EPA will consider the technical 
information and explanations presented by the submitting state and the 
state with which it disagrees when considering whether to approve the 
state's SIP. See id.; 2019 Guidance at 53. Under all circumstances, a 
state must document in its SIP submission all substantive consultations 
with other contributing states. 40 CFR 51.308(f)(2)(ii)(C).

D. Reasonable Progress Goals

    Reasonable progress goals ``measure the progress that is projected 
to be achieved by the control measures states have determined are 
necessary to make reasonable progress based on a four-factor 
analysis.'' 82 FR at 3091. Their primary purpose is to assist the 
public and the EPA in assessing the reasonableness of states' long-term 
strategies for making reasonable progress towards the national 
visibility goal. See 40 CFR 51.308(f)(3)(iii)-(iv). States in which 
Class I areas are located must establish two RPGs, both in deciviews--
one representing visibility conditions on the clearest days and one 
representing visibility on the most anthropogenically impaired days--
for each area within their borders. 40 CFR 51.308(f)(3)(i). The two 
RPGs are intended to reflect the projected impacts, on the two sets of 
days, of the emission reduction measures the state with the Class I 
area, as well as all other contributing states, have included in their 
long-term strategies for the second implementation period.\27\ The RPGs 
also account for the projected impacts of implementing other CAA 
requirements, including non-SIP based requirements. Because RPGs are 
the modeled result of the measures in states' long-term strategies (as 
well as other measures required under the CAA), they cannot be 
determined before states have conducted their four-factor analyses and 
determined the control measures that are necessary to make reasonable 
progress. See 2021 Clarifications Memo at 6.
---------------------------------------------------------------------------

    \27\ RPGs are intended to reflect the projected impacts of the 
measures all contributing states include in their long-term 
strategies. However, due to the timing of analyses and of control 
determinations by other states, other on-going emissions changes, a 
particular state's RPGs may not reflect all control measures and 
emissions reductions that are expected to occur by the end of the 
implementation period. The 2019 Guidance provides recommendations 
for addressing the timing of RPG calculations when states are 
developing their long-term strategies on disparate schedules, as 
well as for adjusting RPGs using a post-modeling approach. 2019 
Guidance at 47-48.
---------------------------------------------------------------------------

    For the second implementation period, the RPGs are set for 2028. 
Reasonable progress goals are not enforceable targets, 40 CFR 
51.308(f)(3)(iii); rather, they ``provide a way for the states to check 
the projected outcome of the [long-term strategy] against the goals for 
visibility improvement.'' 2019 Guidance at 46. While states are not 
legally obligated to achieve the visibility conditions described in 
their RPGs, Sec.  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.'' Thus, states are required to have emission 
reduction measures in their long-term strategies that are projected to 
achieve visibility conditions on the most impaired days that are better 
than the baseline period and show no degradation on the clearest days 
compared to the clearest days from the baseline period. The baseline 
period for the purpose of this comparison is the baseline visibility 
condition--the annual average visibility condition for the period 2000-
2004. See 40 CFR 51.308(f)(1)(i), 82 FR at 3097-98.
    So that RPGs may also serve as a metric for assessing the amount of 
progress a state is making towards the national visibility goal, the 
RHR requires states with Class I areas to compare the 2028 RPG for the 
most impaired days to the corresponding point on the URP line 
(representing visibility conditions in 2028 if visibility were to 
improve at a linear rate from conditions in the baseline period of 
2000-2004 to natural visibility conditions in 2064). If the most 
impaired days RPG in 2028 is above the URP (i.e., if visibility 
conditions are improving more slowly than the rate described by the 
URP), each state that contributes to visibility impairment in the Class 
I area must demonstrate, based on the four-factor analysis required 
under 40 CFR 51.308(f)(2)(i), that no additional emission reduction 
measures would be reasonable to include in its long-term strategy. 40 
CFR 51.308(f)(3)(ii). To this end, 40 CFR 51.308(f)(3)(ii) requires 
that each state contributing to visibility impairment in a Class I area 
that is projected to improve more slowly than the URP provide ``a 
robust demonstration, including documenting the criteria used to 
determine which sources or groups [of] sources were evaluated and how 
the four factors required by paragraph (f)(2)(i) were taken into 
consideration in selecting the measures for inclusion in its long-term 
strategy.'' The 2019 Guidance provides suggestions about how such a 
``robust demonstration'' might be conducted. See 2019 Guidance at 50-
51.
    The 2017 RHR, 2019 Guidance, and 2021 Clarifications Memo also 
explain that projecting an RPG that is on or below the URP based on 
only on-the-books and/or on-the-way control measures (i.e., control 
measures already required or anticipated before the four-factor 
analysis is conducted) is not a ``safe harbor'' from the CAA's and 
RHR's requirement that all states must conduct a four-factor analysis 
to determine what emission reduction measures constitute reasonable 
progress. The URP is a planning metric used to gauge the amount of 
progress made thus far and the amount left before reaching natural

[[Page 58671]]

visibility conditions. However, the URP is not based on consideration 
of the four statutory factors and therefore cannot answer the question 
of whether the amount of progress being made in any particular 
implementation period is ``reasonable progress.'' See 82 FR at 3093, 
3099-3100; 2019 Guidance at 22; 2021 Clarifications Memo at 15-16.

E. 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. A state with Class I areas within its 
borders must submit with its SIP revision a monitoring strategy for 
measuring, characterizing, and reporting regional haze visibility 
impairment that is representative of all Class I areas within the 
state. SIP revisions for such states must also provide for the 
establishment of any additional monitoring sites or equipment needed to 
assess visibility conditions in Class I areas, as well as reporting of 
all visibility monitoring data to the EPA at least annually. Compliance 
with the monitoring strategy requirement may be met through a state's 
participation in the Interagency Monitoring of Protected Visual 
Environments (IMPROVE) monitoring network, which is used to measure 
visibility impairment caused by air pollution at the 156 Class I areas 
covered by the visibility program. 40 CFR 51.308(f)(6), (f)(6)(i), 
(f)(6)(iv). The IMPROVE monitoring data is used to determine the 20% 
most anthropogenically impaired and 20% clearest sets of days every 
year at each Class I area and tracks visibility impairment over time.
    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. 40 CFR 51.308(f)(6)(ii), (iii). Section 
51.308(f)(6)(v) further requires that all states' SIPs provide for a 
statewide inventory of emissions of pollutants that are reasonably 
anticipated to cause or contribute to visibility impairment in any 
Class I area; the inventory must include emissions for the most recent 
year for which data are available and estimates of future projected 
emissions. States must also include commitments to update their 
inventories periodically. The inventories themselves do not need to be 
included as elements in the SIP and are not subject to EPA review as 
part of the Agency's evaluation of a SIP revision.\28\ All states' SIPs 
must also provide for any other elements, including reporting, 
recordkeeping, and other measures, that are necessary for states to 
assess and report on visibility. 40 CFR 51.308(f)(6)(vi). Per the 2019 
Guidance, a state may note in its regional haze SIP that its compliance 
with the Air Emissions Reporting Rule (AERR) in 40 CFR part 51, subpart 
A satisfies the requirement to provide for an emissions inventory for 
the most recent year for which data are available. To satisfy the 
requirement to provide estimates of future projected emissions, a state 
may explain in its SIP how projected emissions were developed for use 
in establishing RPGs for its own and nearby Class I areas.\29\
---------------------------------------------------------------------------

    \28\ See ``Step 8: Additional requirements for regional haze 
SIPs'' in 2019 Regional Haze Guidance at 55.
    \29\ Id.
---------------------------------------------------------------------------

    Separate from the requirements related to monitoring for regional 
haze purposes under 40 CFR 51.308(f)(6), the RHR also contains a 
requirement at Sec.  51.308(f)(4) related to any additional monitoring 
that may be needed to address visibility impairment in Class I areas 
from a single source or a small group of sources. This is called 
``reasonably attributable visibility impairment.'' \30\ Under this 
provision, if the EPA or the FLM of an affected Class I area has 
advised a state that additional monitoring is needed to assess 
reasonably attributable visibility impairment, the state must include 
in its SIP revision for the second implementation period an appropriate 
strategy for evaluating such impairment.
---------------------------------------------------------------------------

    \30\ EPA's visibility protection regulations define ``reasonably 
attributable visibility impairment'' as ``visibility impairment that 
is caused by the emission of air pollutants from one, or a small 
number of sources.'' 40 CFR 51.301.
---------------------------------------------------------------------------

F. 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. See 81 FR 26942, 26950 (May 4, 2016), (82 FR at 3119, 
January 10, 2017). To this end, every state's SIP revision for the 
second implementation period is required to describe the status of 
implementation of all measures included in the state's long-term 
strategy, including BART and reasonable progress emission reduction 
measures from the first implementation period, and the resulting 
emissions reductions. 40 CFR 51.308(g)(1) and (2).
    A core component of the progress report requirements is an 
assessment of changes in visibility conditions on the clearest and most 
impaired days. For second implementation period progress reports, Sec.  
51.308(g)(3) requires states with Class I areas within their borders to 
first determine current visibility conditions for each area on the most 
impaired and clearest days, 40 CFR 51.308(g)(3)(i)(B), and then to 
calculate the difference between those current conditions and baseline 
(2000-2004) visibility conditions in order to assess progress made to 
date. See 40 CFR 51.308(g)(3)(ii)(B). States must also assess the 
changes in visibility impairment for the most impaired and clearest 
days since they submitted their first implementation period progress 
reports. See 40 CFR 51.308(g)(3)(iii)(B), (f)(5). Since different 
states submitted their first implementation period progress reports at 
different times, the starting point for this assessment will vary state 
by state.
    Similarly, states must provide analyses tracking the change in 
emissions of pollutants contributing to visibility impairment from all 
sources and activities within the state over the period since they 
submitted their first implementation period progress reports. See 40 
CFR 51.308(g)(4), (f)(5). Changes in emissions should be identified by 
the type of source or activity. Section 51.308(g)(5) also addresses 
changes in emissions since the period addressed by the previous 
progress report and requires states' SIP revisions to include an 
assessment of any significant changes in anthropogenic emissions within 
or outside the state. This assessment must include an explanation of 
whether these changes in emissions were anticipated and whether they 
have limited or impeded progress in reducing emissions and improving 
visibility relative to what the state projected based on its long-term 
strategy for the first implementation period.

[[Page 58672]]

G. Requirements for State and Federal Land Manager Coordination

    CAA section 169A(d) requires that before a state holds a public 
hearing on a proposed regional haze SIP revision, it must consult with 
the appropriate FLM or FLMs; pursuant to that consultation, the state 
must include a summary of the FLMs' conclusions and recommendations in 
the notice to the public. Consistent with this statutory requirement, 
the RHR also requires that states ``provide the [FLM] with an 
opportunity for consultation, in person and at a point early enough in 
the State's policy analyses of its long-term strategy emission 
reduction obligation so that information and recommendations provided 
by the [FLM] can meaningfully inform the State's decisions on the long-
term strategy.'' 40 CFR 51.308(i)(2). Consultation that occurs 120 days 
prior to any public hearing or public comment opportunity will be 
deemed ``early enough,'' but the RHR provides that in any event the 
opportunity for consultation must be provided at least 60 days before a 
public hearing or comment opportunity. This consultation must include 
the opportunity for the FLMs to discuss their assessment of visibility 
impairment in any Class I area and their recommendations on the 
development and implementation of strategies to address such 
impairment. 40 CFR 51.308(i)(2). In order for the EPA to evaluate 
whether FLM consultation meeting the requirements of the RHR has 
occurred, the SIP submission should include documentation of the timing 
and content of such consultation. The SIP revision submitted to the EPA 
must also describe how the state addressed any comments provided by the 
FLMs. 40 CFR 51.308(i)(3). Finally, a SIP revision must provide 
procedures for continuing consultation between the state and FLMs 
regarding the state's visibility protection program, including 
development and review of SIP revisions, five-year progress reports, 
and the implementation of other programs having the potential to 
contribute to impairment of visibility in Class I areas. 40 CFR 
51.308(i)(4).

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

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

    CT DEEP submitted its regional haze SIP for the first 
implementation period to the EPA on November 18, 2009, and supplemented 
it on February 24, 2012, and March 12, 2012. The EPA approved 
Connecticut's first implementation period regional haze SIP submission 
on July 10, 2014 (79 FR 39322). EPA's approval included, but was not 
limited to, the portions of the plan that address the reasonable 
progress requirements, Connecticut's maintenance of nitrogen oxide 
emissions controls, as well as Connecticut's low sulfur fuel program. 
The requirements for regional haze SIPs for the first implementation 
period are contained in 40 CFR 51.308(d) and (e). 40 CFR 51.308(b). 
Pursuant to 40 CFR 51.308(g), Connecticut was also responsible for 
submitting a five-year progress report as a SIP revision for the first 
implementation period, which it did on June 30, 2015. The EPA approved 
the progress report into the Connecticut SIP on November 26, 2019 (84 
FR 65007).

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

    In accordance with CAA sections 169A and the RHR at 40 CFR 
51.308(f), on January 5, 2022, Connecticut submitted a revision to the 
Connecticut SIP to address its regional haze obligations for the second 
implementation period, which runs through 2028. Connecticut made a 
draft Regional Haze SIP submission available for public comment on 
December 3, 2020. Connecticut has included the public comments and its 
responses to those comments in the submission.
    The following sections describe Connecticut's SIP submission, 
including analyses conducted by MANEVU and Connecticut's determinations 
based on those analyses, Connecticut's assessment of progress made 
since the first implementation period in reducing emissions of 
visibility impairing pollutants, and the visibility improvement 
progress at nearby Class I areas. This document also contains EPA's 
evaluation of Connecticut'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. 
Connecticut has no mandatory Class I Federal area within its borders.
    For the second implementation period, MANEVU performed technical 
analyses \31\ to help assess source and state-level contributions to 
visibility impairment and the need for interstate consultation. MANEVU 
used the results of these analyses to determine which states' emissions 
``have a high likelihood of affecting visibility in MANEVU's Class I 
areas.'' \32\ Similar to metrics used in the first implementation 
period,\33\ MANEVU used a greater than 2 percent of sulfate plus 
nitrate emissions contribution criteria to determine whether emissions 
from individual jurisdictions within the region affected visibility in 
any Class I areas. The MANEVU analyses for the second implementation 
period used a combination of data analysis techniques, including 
emissions data, distance from Class I areas, wind trajectories, and 
CALPUFF dispersion modeling. Although many of the analyses focused only 
on SO2 emissions and resultant particulate sulfate 
contributions to visibility impairment, some also incorporated 
NOX emissions to estimate particulate nitrate contributions.
---------------------------------------------------------------------------

    \31\ The contribution assessment methodologies for MANEVU Class 
I areas are summarized in CT RH SIP appendix ``Selection of States 
for MANEVU Regional Haze Consultation (2018),'' MANEVU TSC. 
September 5, 2017.
    \32\ Id.
    \33\ See docket EPA-R01-OAR-2023-0186 for MANEVU supporting 
materials.
---------------------------------------------------------------------------

    One MANEVU analysis used for contribution assessment was CALPUFF 
air dispersion modeling. The CALPUFF model was used to estimate sulfate 
and nitrate formation and transport in MANEVU and nearby regions 
originating from large electric generating unit (EGU) point sources and 
other large industrial and institutional sources in the eastern and 
central United States. Information from an initial round of CALPUFF 
modeling was collated for the 444 EGUs that were determined to warrant 
further scrutiny based on their emissions of SO2 and 
NOX. The list of EGUs was based on an enhanced ``Q/d'' 
analysis \34\ that considered recent SO2

[[Page 58673]]

emissions in the eastern United States and an analysis that adjusted 
previous 2002 MANEVU CALPUFF modeling by applying a ratio of 2011 to 
2002 SO2 emissions. This list of sources was then enhanced 
by including the top five SO2 and NOX emission 
sources for 2011 for each state included in the modeling domain. A 
total of 311 EGU stacks (as opposed to individual units) were included 
in the CALPUFF modeling analysis. Initial information was also 
collected on the 50 industrial and institutional sources that, 
according to 2011 Q/d analysis, contributed the most to visibility 
impact in each Class I area. The ultimate CALPUFF modeling run included 
a total of 311 EGU stacks and 82 industrial facilities. The summary 
report for the CALPUFF modeling included the top 10 most impacting EGUs 
and the top 5 most impacting industrial/institutional sources for each 
Class I area and compiled those results into a ranked list of the most 
impacting EGUs and industrial sources at MANEVU Class I areas.\35\ 
Overall, MANEVU found that emission sources located close to Class I 
areas typically show higher visibility impacts than similarly sized 
facilities further away. However, visibility degradation appears to be 
dominated by the more distant emission sources due to their larger 
emissions. Connecticut had three EGUs identified in the CALPUFF 
modeling as having a magnitude of emissions located close enough to a 
Class I area that they could have the potential for visibility impacts: 
Middletown Unit 4, Bridgeport Harbor Station Unit 3, and New Haven 
Harbor Unit 1.\36\
---------------------------------------------------------------------------

    \34\ ``Q/d'' is emissions (Q) in tons per year, 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.
    \35\ See ``2016 MANEVU Source Contribution Modeling Report--
CALPUFF Modeling of Large Electrical Generating Units and Industrial 
Sources.'' MANEVU TSC. April 4, 2017.
    \36\ Connecticut Regional Haze SIP Revision at 45.
---------------------------------------------------------------------------

    As explained above, 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,'' 64 FR at 35721, 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. Consistent with these 
requirements, the 2019 Guidance makes it clear that ``all types of 
anthropogenic sources are to be included in the determination'' of 
whether a state's emissions are reasonably anticipated to result in any 
visibility impairment. 2019 Guidance at 8.
    The screening analyses on which MANEVU relied are useful for 
certain purposes. MANEVU used information from its technical analysis 
to rank the largest contributing states to sulfate and nitrate 
impairment in the seven MANEVU Class I areas and three additional, 
nearby Class I areas.\37\ The rankings were used to determine upwind 
states that MANEVU deemed important to include in state-to-state 
consultation based on an identified visibility impact screening 
threshold. Additionally, large individual source impacts were used to 
target MANEVU control analysis ``Asks'' \38\ of states and sources both 
within and upwind of MANEVU.\39\ The EPA finds the nature of the 
analyses generally appropriate to support decisions on states with 
which to consult. However, we have cautioned that source selection 
methodologies that target the largest regional contributors to 
visibility impairment across multiple states may not be reasonable for 
a particular state if it results in few or no sources being selected 
for subsequent analysis. 2021 Clarifications Memo at 3.
---------------------------------------------------------------------------

    \37\ The Class I areas analyzed were Acadia National Park in 
Maine, Brigantine Wilderness in New Jersey, Great Gulf Wilderness 
and Presidential Range--Dry River Wilderness in New Hampshire, Lye 
Brook Wilderness in Vermont, Moosehorn Wilderness in Maine, 
Roosevelt Campobello International Park in New Brunswick, Shenandoah 
National Park in Virginia, James River Face Wilderness in Virginia, 
and Dolly Sods/Otter Creek Wildernesses in West Virginia.
    \38\ As explained more fully in section IV.E.a., MANEVU refers 
to each of the components of its overall strategy as an ``Ask ``of 
its member states.
    \39\ The MANEVU consultation report explains that ``[t]he 
objective of this technical work was to identify states and sources 
from which MANEVU will pursue further analysis. This screening was 
intended to identify which states to invite to consultation, not a 
definitive list of which states are contributing.''
---------------------------------------------------------------------------

    With regard to the analysis and determinations regarding 
Connecticut's contribution to visibility impairment at out-of-state 
Class I areas, the MANEVU technical work focuses on the magnitude of 
visibility impacts from certain Connecticut emissions on nearby Class I 
areas. The MANEVU contribution screening results estimate Connecticut's 
highest percent mass-weighted sulfate and nitrate contribution to be 
1.4% at Moosehorn Wilderness and Roosevelt Campobello International 
Park, with Acadia National Park and the Lye Brook Wilderness the next 
closest Class I areas impacted by Connecticut emissions at 1.3% and 
1.2%, respectively.\40\ However, the MANEVU analyses did not account 
for all emissions and all components of visibility impairment (e.g., 
primary PM emissions, and impairment from fine PM, elemental carbon, 
and organic carbon). In addition, Q/d analyses with a relatively 
simplistic accounting for wind trajectories and CALPUFF applied to a 
very limited set of EGUs and major industrial sources of SO2 
and NOX are not scientifically rigorous tools capable of 
evaluating contribution to visibility impairment from all emissions in 
a state. The EPA acknowledges that the contribution to visibility 
impairment from Connecticut's emissions at nearby out-of-state Class I 
areas is smaller than that from numerous other states. While some 
MANEVU states noted that the contributions from several states outside 
the MANEVU region are significantly larger than its own, we again 
clarify that each state is obligated under the CAA and RHR to address 
regional haze visibility impairment resulting from emissions from 
within the state, irrespective of whether another state's contribution 
is greater. See 2021 Clarifications Memo at 3. Additionally, we note 
that the 2 percent or greater sulfate-plus-nitrate threshold used to 
determine whether Connecticut emissions contribute to visibility 
impairment at a particular Class I area may be higher than what EPA 
believes is an ``extremely low triggering threshold'' intended by the 
statute and regulations. In sum, based on the information provided, it 
is clear that emissions from Connecticut have relatively small 
contributions to Class I areas. However, due to the low triggering 
threshold implied by the Rule and the lack of rigorous modeling 
analyses, we do not necessarily agree with the level of the State's 2% 
contribution threshold.
---------------------------------------------------------------------------

    \40\ See table 4-1 of the CT RH SIP.
---------------------------------------------------------------------------

    In any event, pursuant to the regulatory requirements, Connecticut 
took part in the emission control strategy consultation process as a 
member of MANEVU. As part of that process, MANEVU developed a set of 
emissions reduction measures identified as being necessary to make 
reasonable progress in the seven MANEVU Class I areas. This strategy 
consists of six Asks for states within MANEVU and five Asks for states 
outside the region that were found to impact visibility at Class I 
areas within MANEVU.\41\ Connecticut's submission discusses each of the 
Asks and explains why or why not each is applicable and how it has 
complied with the relevant components of the emissions control strategy 
the MANEVU states laid out. Connecticut worked with MANEVU to determine 
potential reasonable

[[Page 58674]]

measures that could be implemented by 2028, considering the cost of 
compliance, the time necessary for compliance, the energy and non-air 
quality environmental impacts, and the remaining useful life of any 
potentially affected sources.\42\ As discussed in further detail below, 
the EPA is proposing to find that Connecticut has submitted a regional 
haze plan that meets the requirements of 40 CFR 51.308(f)(2) related to 
the development of a long-term strategy. Thus, we propose to find that 
Connecticut has satisfied the applicable requirements for making 
reasonable progress towards natural visibility conditions in Class I 
areas that may be affected by emissions from the state.
---------------------------------------------------------------------------

    \41\ See section 5.1 of the CT RH SIP.
    \42\ See 42 U.S.C. 7491(g)(1); 40 CFR 51.308(f)(2)(i).
---------------------------------------------------------------------------

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. 40 CFR 
51.308(f)(1)(vi)(B).
    Connecticut has no Class I areas. MANEVU Class I areas, as well as 
other nearby Class I areas that MANEVU examined, are listed below. 
MANEVU used certain areas (as noted below) to represent nearby Class I 
areas where monitors do not exist.\43\
---------------------------------------------------------------------------

    \43\ Mid-Atlantic/Northeast U.S. Visibility Data, 2004-2017 (2nd 
RH SIP Metrics). MANEVU (prepared by Maine Department of 
Environmental Protection). December 18, 2018 revision. p.2-1 
(appendix 22).
---------------------------------------------------------------------------

    The MANEVU Class I Areas are Lye Brook Wilderness Area (Vermont), 
Great Gulf Wilderness Area (New Hampshire) (used to represent 
Presidential Range--Dry River Wilderness Area), Presidential Range--Dry 
River Wilderness Area (New Hampshire), Acadia National Park (Maine), 
Moosehorn Wildlife Refuge (Maine) (used to represent Roosevelt 
Campobello International Park), Roosevelt Campobello International Park 
(New Brunswick, Canada), Brigantine Wildlife Refuge (New Jersey). 
Nearby Class I Areas consist of Dolly Sods Wilderness Area (West 
Virginia) (used to represent Otter Creek Wilderness Area), Otter Creek 
Wilderness Area (West Virginia), Shenandoah National Park (Virginia), 
and James River Face Wilderness Area (Virginia).

E. Long-Term Strategy for Regional Haze

a. Connecticut's Response to the Six MANEVU Asks
    Each state having a Class I area within its borders or emissions 
that may affect visibility in a Class I area must develop a long-term 
strategy for making reasonable progress towards the national visibility 
goal. CAA section 169A(b)(2)(B). As explained in the Background section 
of this document, reasonable progress is achieved when all states 
contributing to visibility impairment in a Class I area are 
implementing the measures determined--through application of the four 
statutory factors to sources of visibility impairing pollutants--to be 
necessary to make reasonable progress. 40 CFR 51.308(f)(2)(i). Each 
state's long-term strategy must include the enforceable emission 
limitations, compliance schedules, and other measures that are 
necessary to make reasonable progress. 40 CFR 51.308(f)(2). All new 
(i.e., additional) measures that are the outcome of four-factor 
analyses are necessary to make reasonable progress and must be in the 
long-term strategy. If the outcome of a four-factor analysis and other 
measures necessary to make reasonable progress is that no new measures 
are reasonable for a source, that source's existing measures are 
necessary to make reasonable progress, unless the state can demonstrate 
that the source will continue to implement those measures and will not 
increase its emission rate. Existing measures that are necessary to 
make reasonable progress must also be in the long-term strategy. In 
developing its long-term strategies, a state must also consider the 
five additional factors in Sec.  51.308(f)(2)(iv). As part of its 
reasonable progress determinations, the state must describe the 
criteria used to determine which sources or group of sources were 
evaluated (i.e., subjected to four-factor analysis) for the second 
implementation period and how the four factors were taken into 
consideration in selecting the emission reduction measures for 
inclusion in the long-term strategy. 40 CFR 51.308(f)(2)(i).
    The following section summarizes how Connecticut's SIP submission 
addressed the requirements of Sec.  51.308(f)(2)(i); specifically, it 
describes MANEVU's development of the six Asks and how Connecticut 
addressed each. The regulations Connecticut identifies as a result of 
its responses to the six Asks comprise Connecticut's long-term strategy 
for the second planning period to address regional haze visibility 
impairment for each mandatory Class I Federal area that may be affected 
by emissions from Connecticut. When developing the Asks with the other 
MANEVU states and applying them to sources in Connecticut, the State 
considered the four statutory factors and the additional regulatory 
factors and identified emissions control measures necessary to make 
reasonable progress towards the goal of preventing of any future, and 
remedying any existing, anthropogenic visibility impairment in Class I 
areas that may be affected by emissions from Connecticut. Connecticut's 
SIP submission describes how it plans to meet the long-term strategy 
requirements defined by the State and MANEVU via its responses to the 
``Asks.'' The EPA's evaluation of Connecticut's long-term strategy is 
contained in section IV.E.b.
    States may rely on technical information developed by the RPOs of 
which they are members to select sources for four-factor analysis and 
to conduct that analysis, as well as to satisfy the documentation 
requirements under Sec.  51.308(f). Where an RPO has performed source 
selection and/or four-factor analyses (or considered the five 
additional factors in Sec.  51.308(f)(2)(iv)) for its member states, 
those states may rely on the RPO's analyses for the purpose of 
satisfying the requirements of Sec.  51.308(f)(2)(i) so long as the 
states have a reasonable basis to do so and all state participants in 
the RPO process have approved the technical analyses. 40 CFR 
51.308(f)(2)(iii). States may also satisfy the requirement of Sec.  
51.308(f)(2)(ii) to engage in interstate consultation with other states 
that have emissions that are reasonably anticipated to contribute to 
visibility impairment in a given Class I area under the auspices of 
intra- and inter-RPO engagement.
    Connecticut is a member of the MANEVU RPO and participated in the 
RPO's regional approach to developing a strategy for making reasonable 
progress towards the national visibility goal in the MANEVU Class I 
areas. MANEVU's strategy includes a combination of: (1) measures for 
certain source sectors and groups of sectors that the RPO determined 
were reasonable for

[[Page 58675]]

states to pursue, and (2) a request for member states to conduct four-
factor analyses for individual sources that it identified as 
contributing to visibility impairment. MANEVU refers to each of the 
components of its overall strategy as an ``Ask'' of its member states. 
On August 25, 2017, the Executive Director of MANEVU, on behalf of the 
MANEVU states and tribal nations, signed a statement that identifies 
six emission reduction measures that comprise the Asks for the second 
implementation period.\44\ The Asks were ``designed to identify 
reasonable emission reduction strategies that must be addressed by the 
states and tribal nations of MANEVU through their regional haze SIP 
updates.'' \45\ The statement explains that ``[i]f any State cannot 
agree with or complete a Class I State's Asks, the State must describe 
the actions taken to resolve the disagreement in the Regional Haze 
SIP.'' \46\
---------------------------------------------------------------------------

    \44\ See ``MANEVU Regional Haze Consultation Report and 
Consultation Documentation--Final.''
    \45\ Id.
    \46\ Id.
---------------------------------------------------------------------------

    MANEVU's recommendations as to the appropriate control measures 
were based on technical analyses documented in the RPO's reports and 
included as appendices to, or referenced in, Connecticut's regional 
haze SIP submission. One of the initial steps of MANEVU's technical 
analysis was to determine which visibility-impairing pollutants should 
be the focus of its efforts for the second implementation period. In 
the first implementation period, MANEVU determined that sulfates were 
the most significant visibility impairing pollutant at the region's 
Class I areas. To determine the impact of certain pollutants on 
visibility at Class I areas for the purpose of second implementation 
period planning, MANEVU conducted an analysis comparing the pollutant 
contribution on the clearest and most impaired days in the baseline 
period (2000-2004) to the most recent period (2012-2016) \47\ at MANEVU 
and nearby Class I areas. MANEVU found that while SO2 
emissions were decreasing and visibility was improving, sulfates still 
made up the most significant contribution to visibility impairment at 
MANEVU and nearby Class I areas. According to the analysis, 
NOX emissions have begun to play a more significant role in 
visibility impacts in recent years as SO2 emissions have 
decreased. The technical analyses used by Connecticut are included in 
its submission and are as follows: \48\
---------------------------------------------------------------------------

    \47\ The period of 2012-2016 was the most recent period for 
which data were available at the time of analysis.
    \48\ These documents can be found in the docket for this 
rulemaking.
---------------------------------------------------------------------------

     2016 Updates to the Assessment of Reasonable Progress for 
Regional Haze in MANEVU Class I Areas;
     Impact of Wintertime SCR/SNCR Optimization on Visibility 
Impairing Nitrate Precursor Emissions. November 2017;
     High Electric Demand Days and Visibility Impairment in 
MANEVU. December 2017;
     Benefits of Combined Heat and Power Systems for Reducing 
Pollutant Emissions in MANEVU States. March 2016;
     2016 MANEVU Source Contribution Modeling Report--CALPUFF 
Modeling of Large Electrical Generating Units and Industrial Sources. 
April 4, 2017;
     Contribution Assessment Preliminary Inventory Analysis. 
October 10, 2016;
     Four-Factor Data Collection Memo. March 2017;
     Status of the Top 167 Stacks from the 2008 MANEVU Ask. 
July 2016;
     Mid-Atlantic/Northeast U.S. Visibility Data, 2004-2019 
(2nd RH SIP Metrics);
     Selection of States for MANEVU Regional Haze Consultation 
2018;
     Ozone Transport Commission/MANEVU 2011 Based Modeling 
Platform Support Document October (2018 Update).
    MANEVU gathered information on each of the four statutory factors 
for six source sectors it determined, based on an examination of annual 
emission inventories, ``had emissions [of SO2 and/or 
NOX] that were reasonabl[y] anticipated to contribute to 
visibility degradation in MANEVU:'' electric generating units (EGUs), 
industrial/commercial/institutional boilers (ICI boilers), cement 
kilns, heating oil, residential wood combustion, and outdoor wood 
combustion.\49\ MANEVU also collected data on individual sources within 
the EGU, ICI boiler, and cement kiln sectors.\50\ Information for the 
six sectors included explanations of technically feasible control 
options for SO2 or NOX, illustrative cost-
effectiveness estimates for a range of model units and control options, 
sector-wide cost considerations, potential time frames for compliance 
with control options, potential energy and non-air-quality 
environmental impacts of certain control options, and how the remaining 
useful lives of sources might be considered in a control analysis.\51\ 
Source-specific data included SO2 emissions \52\ and 
existing controls \53\ for certain existing EGUs, ICI boilers, and 
cement kilns. MANEVU considered this information on the four factors as 
well as the analyses developed by the RPO's Technical Support Committee 
when it determined specific emission reduction measures that were found 
to be reasonable for certain sources within two of the sectors it had 
examined--EGUs and ICI boilers.\54\ The Asks were based on this 
analysis and looked to either optimize the use of existing controls, 
have states conduct further analysis on EGU or ICI boilers with 
considerable visibility impacts, implement low sulfur fuel standards, 
or lock-in lower emission rates.
---------------------------------------------------------------------------

    \49\ See ``MANEVU Four Factor Data Collection Memo,'' at 1, 
March 30, 2017.
    \50\ See ``2016 Updates to the Assessment of Reasonable Progress 
for Regional Haze in MANEVU Class I Areas,'' Jan. 31, 2016.
    \51\ Id.
    \52\ See ``Four Factor Data Collection Memo.''
    \53\ See ``Status of the Top 167 Stacks from the 2008 MANEVU 
Ask. July 2016.''
    \54\ See ``Four Factor Data Collection Memo''; 2016 Updates to 
the Assessment of Reasonable Progress for Regional Haze in MANEVU 
Class I Areas.''
---------------------------------------------------------------------------

    MANEVU Ask 1 is ``Electric Generating Units (EGUs) with a nameplate 
capacity larger than or equal to 25 MW with already installed 
NOX and/or SO2 controls--ensure the most 
effective use of control technologies on a year-round basis to 
consistently minimize emissions of haze precursors or obtain equivalent 
alternative emission reductions.'' MANEVU observed that EGUs often only 
run NOX emissions controls to comply with ozone season 
trading programs and consequently, NOX sources may be 
uncontrolled during the winter and non-peak summer days. MANEVU found 
that: (1) running existing installed controls [selective catalytic 
reduction (SCR) and selective non-catalytic reduction (SNCR)] is one of 
the most cost-effective ways to control NOX emissions from 
EGUs; and (2) that running existing controls year-round could 
substantially reduce the NOX emissions in many of the states 
upwind of Class I areas in MANEVU that lead to visibility impairment 
during the winter from nitrates.\55\ MANEVU included this as an 
emission management strategy because large EGUs had already been 
identified as dominant contributors to visibility impairment and the 
low cost of running already installed controls made it reasonable.
---------------------------------------------------------------------------

    \55\ See ``Impact of Wintertime SCR/SNCR Optimization on 
Visibility Impairing Nitrate Precursor Emissions.''
---------------------------------------------------------------------------

    Connecticut identified 33 EGU units that meet the criteria of 25 MW 
or larger

[[Page 58676]]

with installed controls.\56\ Connecticut explained that all of these 
units identified are turbines with Selective Catalytic Reduction (SCR) 
to control nitrogen oxides with the exception of Middletown Unit 3, 
which is a boiler controlled by Selective Non-Catalytic Reduction 
(SNCR) to reduce emissions of nitrogen oxides. Connecticut further 
explained that these sources are subject to requirements to maintain 
and operate the control equipment to minimize emissions and are made 
enforceable through record keeping and reporting requirements contained 
in Regulations of Connecticut State Agencies (RCSA) section 22a-174-7 
and the indicated new source review permits. These units are all Title 
V sources, and the requirements and enforceability are reviewed at 
least once every five years and are federally enforceable as well. 
Connecticut also noted that are no electric generating units of 25 MW 
or more with control devices to treat emissions of sulfur oxides and 
that Connecticut generally addresses sulfur emissions ``on the front 
end'' via sulfur-in-fuel restrictions.\57\ Connecticut concluded that 
it has therefore met the requirements of Ask 1.
---------------------------------------------------------------------------

    \56\ See table 5-1 of the Connecticut submittal.
    \57\ See, for example, the discussion of Ask 3 below.
---------------------------------------------------------------------------

    MANEVU Ask 2 consists of a request that states ``Emission sources 
modeled by MANEVU that have the potential for 3.0 Mm-1 or 
greater visibility impacts at any MANEVU Class I area, as identified by 
MANEVU contribution analyses . . . perform a four-factor analysis for 
reasonable installation or upgrade to emission controls.'' Based on an 
examination of visibility impact modeling results, MANEVU concluded 
that a 3.0 Mm-1 cutoff captured an appropriately-sized group 
of sources contributing the largest percentage of visibility impairing 
pollutants to Class I areas in the MANEVU states.\58\ For units 
identified for the Ask 2 analysis, MANEVU requested that states 
determine reasonable controls through the consideration of the four 
factors on a state-by-state and unit-by-unit basis. MANEVU's analysis 
for Ask 2 did not identify any units in Connecticut with a potential 
impact of at least 3.0 Mm-1.\59\ Connecticut notes that the 
highest estimated impact from any Connecticut source to any Class I 
area is just over 1.0 Mm-1. Furthermore, this particular 
source--Bridgeport Harbor Station Unit 3--shuttered in 2021.\60\ Based 
on the lack of identified sources at or above the 3.0 Mm-1 
threshold, Connecticut concluded that it met Ask 2.
---------------------------------------------------------------------------

    \58\ Units with smaller contributions of visibility-impairing 
pollutants were captured by other Asks.
    \59\ See MANEVU Intra-Regional Ask Final August 25, 2017.
    \60\ CT DEEP revoked the operating permit for Bridgeport Harbor 
Station Unit 3 on October 28, 2021. See ``Combined NSR & 
Registration Revocation Letter'' in the docket for this rulemaking.
---------------------------------------------------------------------------

    MANEVU Ask 3 is: ``Each MANEVU State that has not yet fully adopted 
an ultra-low sulfur fuel oil standard as requested by MANEVU in 2007--
pursue this standard as expeditiously as possible and before 2028, 
depending on supply availability, where the standards are as follows: 
a. distillate oil to 0.0015% sulfur by weight (15 ppm); b. #4 residual 
oil within a range of 0.25 to 0.5% sulfur by weight; and c. #6 residual 
oil within a range of 0.3 to 0.5% sulfur by weight.'' Connecticut 
explained that the State has an ultra-low sulfur fuel program, with the 
most recent sulfur content limitations effective as of July 1, 2018. 
Connecticut's ultra-low sulfur fuel program consists of Connecticut 
General Statutes (CGS) section 16a-21a and RCSA sections 22a-174-19a 
and 22a-174-19b. CGS 16a-21a and RCSA 22a-174-19a limit the sulfur 
content of home heating oil to 15ppm and the sulfur content of off-road 
diesel to 3000 ppm (0.3%S). RCSA 22a-174-19b further limits sulfur 
content of fuel oil sold in Connecticut for use in stationary sources 
to 15 ppm for distillate and 3000 ppm (0.3%S) for aviation and residual 
fuels. EPA approved the latest revisions of these rules into 
Connecticut's SIP on May 25, 2016 (81 FR 33134). Based on the above, 
Connecticut concluded that the State's low sulfur fuel program meets 
Ask 3.
    MANEVU Ask 4 requests states to update permits to ``lock in'' lower 
emissions rates for NOX, SO2, and PM at emissions 
sources larger than 250 million British Thermal Units (MMBtu) per hour 
heat input that have switched operations to lower emitting fuels. 
Connecticut explained that EGUs and large sources in the State are 
subject to Title V permitting requirements under RCSA section 22a-174-
33, and that the permits for these sources are reviewed every five 
years and specify allowable operating scenarios, including the type of 
fuels fired. Connecticut further explained that Title V permit 
conditions for these sources related to lower emitting fuels stem from 
Connecticut's sulfur-in-fuel regulations (RCSA sections 22a-174-19a and 
-19b), New Source Review (NSR) permits, and trading orders that 
restrict oil firing in favor of natural gas. A change in fuel type not 
allowed by permit would trigger requirements for a new or modified 
permit under RCSA section 22a-174-3a and -33. Connecticut concluded 
that it therefore met the requirements of Ask 4.
    Ask 5 requests that MANEVU states ``control NOX 
emissions for peaking combustion turbines that have the potential to 
operate on high electric demand days'' by either: (1) Meeting 
NOX emissions standards specified in the Ask for turbines 
that run on natural gas and fuel oil, (2) performing a four-factor 
analysis for reasonable installation of or upgrade to emission 
controls, or (3) obtaining equivalent emission reductions on high 
electric demand days.\61\ The Ask requests states to strive for 
NOX emission standards of no greater than 25 ppm for natural 
gas and 42 ppm for fuel oil, or at a minimum, NOX emissions 
standards of no greater than 42 ppm for natural gas and 96 ppm at for 
fuel oil.
---------------------------------------------------------------------------

    \61\ See ``MANEVU Regional Haze Consultation Report and 
Consultation Documentation--Final.''
---------------------------------------------------------------------------

    Connecticut identified two state regulations EPA previously 
approved into Connecticut's SIP that limit NOX emissions 
from electric generating units and other stationary sources. RCSA 
section 22a-174-22e (86 FR 37053) prescribes averaging times and 
emission limits for units at major sources of NOX. RCSA 
section 22a-174-22f (82 FR 35454) applies to generators at non-major 
facilities during the summer season, and section 22a-174-22f(e)(4) 
requires that any affected unit that exceeds the allowable daily 
thresholds is to be subject to the same limits that apply to sources in 
RCSA section 22a-174-22e. The requirements of RCSA section 22a-174-22e 
were phased-in over two implementation periods. The first phase became 
effective June 1, 2018, and the second phase became effective June 1, 
2023. Under Phase 2, daily NOX limits for combined cycle 
turbines are set at 25 ppm for natural gas and 42 ppm for fuel oil, 
RCSA section 22a-174-22e(d)(5)(C), and daily NOX limits for 
simple cycle turbines are set at 40 ppm for natural gas and 50 ppm for 
fuel oil, id. section 22a-174-22e(d)(4)(C). Connecticut noted that 
these already adopted rules to control nitrogen oxide emissions from 
peaking turbines are at least as stringent as the limits in Ask 5.\62\ 
Therefore, Connecticut concluded that it fully addressed Ask 5.
---------------------------------------------------------------------------

    \62\ See table 5-2 of the CT RH SIP.
---------------------------------------------------------------------------

    The last Ask for states within MANEVU (Ask 6) requests states to 
report in their regional haze SIPs about programs that decrease energy 
demand

[[Page 58677]]

and increase the use of combined heat and power (CHP) and other 
distributed generation technologies such as fuel cells, wind and solar. 
Connecticut asserted that the state continues to support programs to 
increase energy efficiency, CHP, and other clean energy technologies. 
The submittal provides as an example Energize Connecticut\SM\, which it 
describes as an initiative of the Connecticut Energy Efficiency Fund, 
the Connecticut Green Bank, the State, and local utilities dedicated to 
saving energy and building a clean energy future for everyone in the 
state. The initiative has funding support from a charge on customer 
energy bills. Connecticut reports that energy savings efforts through 
2018 have resulted in emissions avoidance of the equivalent of one 130 
MW power plant. Connecticut also identified off-shore wind programs, 
State Executive Order No. 3 (which commits the CT DEEP, in consultation 
with the Connecticut Public Utilities Regulatory Authority to analyze 
and recommend strategies for achieving a carbon emissions free goal for 
the electricity-generating sector by 2040), and the state's membership 
in the Regional Greenhouse Gas Initiative (RGGI) as programs that 
provide air quality benefits. Connecticut therefore concluded that it 
satisfies Ask 6.
    In summary, Connecticut identified the following SIP-approved 
programs as necessary for reasonable progress and therefore included in 
the State's long term strategy: RCSA 22a-174-19a, Control of sulfur 
dioxide emissions from power plants and other large stationary sources 
of air pollution; RCSA 22a-174-19b, Fuel sulfur content limitations for 
stationary sources; RCSA 22a-174-22e, Control of nitrogen oxides 
emissions from fuel-burning equipment at major stationary sources of 
nitrogen oxides; RCSA 22a-174-22f, High daily NOX emitting 
units at non-major sources of NOX; and RCSA 22a-174-38, 
Municipal Waste Combustors.\63\
---------------------------------------------------------------------------

    \63\ See CT RH Submittal at 75, 78.
---------------------------------------------------------------------------

b. The EPA's Evaluation of Connecticut's Response to the Six MANEVU 
Asks and Compliance With Sec.  51.308(f)(2)(i)
    The EPA is proposing to find that Connecticut has satisfied the 
requirements of Sec.  51.308(f)(2)(i) related to evaluating sources and 
determining the emission reduction measures that are necessary to make 
reasonable progress by considering the four statutory factors. We are 
proposing to find that Connecticut has satisfied the four-factor 
analysis requirement through its analysis and actions to address MANEVU 
Ask 3.
    As explained above, Connecticut relied on MANEVU's technical 
analyses and framework (i.e., the Asks) to select sources and develop 
its long-term strategy. MANEVU conducted an inventory analysis to 
identify the source sectors that produced the greatest amount of 
SO2 and NOX emissions in 2011; inventory data 
were also projected to 2018. Based on this analysis, MANEVU identified 
the top-emitting sectors for each of the two pollutants, which for 
SO2 include coal-fired EGUs, industrial boilers, oil-fired 
EGUs, and oil-fired area sources including residential, commercial, and 
industrial sources. Major-emitting sources of NOX include 
on-road vehicles, non-road vehicles, and EGUs.\64\ The RPO's 
documentation explains that ``[EGUs] emitting SO2 and 
NOX and industrial point sources emitting SO2 
were found to be sectors with high emissions that warranted further 
scrutiny. Mobile sources were not considered in this analysis because 
any ask concerning mobile sources would be made to EPA and not during 
the intra-RPO and inter-RPO consultation process among the states and 
tribes.'' \65\ EPA proposes to find that Connecticut reasonably 
evaluated the two pollutants--SO2 and NOX--that 
currently drive visibility impairment within the MANEVU region and that 
it adequately explained and supported its decision to focus on these 
two pollutants through its reliance on the MANEVU technical analyses 
cited in its submission.
---------------------------------------------------------------------------

    \64\ See ``Contributions to Regional Haze in the Northeast and 
Mid-Atlantic United States: Mid-Atlantic/Northeast Visibility Union 
(MANEVU) Contribution Assessment. NESCAUM. August 2006.''
    \65\ See ``Mid-Atlantic/Northeast U.S. Visibility Data, 2004-
2019 (2nd RH SIP Metrics). MANEVU (prepared by Maine Department of 
Environmental Protection). January 21, 2021, revision.''
---------------------------------------------------------------------------

    Section 51.308(f)(2)(i) requires states to evaluate and determine 
the emission reduction measures that are necessary to make reasonable 
progress by applying the four statutory factors to sources in a control 
analysis. As explained previously, the MANEVU Asks are a mix of 
measures for sectors and groups of sources identified as reasonable for 
states to address in their regional haze plans. Several of the Asks 
include analyses of emissions controls, and Connecticut identifies 
numerous existing controls that are in the SIP and are included in the 
long-term strategy. While MANEVU formulated the Asks to be ``reasonable 
emission reduction strategies'' to control emissions of visibility 
impairing pollutants,\66\ Ask 3 (adoption of ultra-low sulfur fuel oil) 
engages with the requirement that states determine the emission 
reduction measures that are necessary to make reasonable progress 
through consideration of the four factors. As laid out in further 
detail below, the EPA is proposing to find that MANEVU's four-factor 
analysis conducted to support the emission reduction measures in Ask 3, 
satisfies the requirement of Sec.  51.308(f)(2)(i). The emission 
reduction measures that are necessary to make reasonable progress must 
be included in the long-term strategy, i.e., in Connecticut's SIP. 40 
CFR 51.308(f)(2).
---------------------------------------------------------------------------

    \66\ Id.
---------------------------------------------------------------------------

    Connecticut asserted that it satisfies Ask 1 because the state 
permits for the EGUs covered by this Ask include year-round emission 
limits and require that controls be run at all times the units are in 
operation and emitting air pollutants. Furthermore, the requirements to 
maintain and operate the control equipment to minimize emissions are 
made enforceable through record keeping and reporting requirements 
contained in previously SIP-approved RCSA section 22a-174-7 (79 FR 
41427) and New Source Review permits. As each of these units are at 
Title V sources, the requirements are federally enforceable, and 
Connecticut renews the permits every five years. EPA thus agrees that 
Connecticut satisfied Ask 1.
    Ask 2 addresses the sources MANEVU determined have the potential 
for larger than, or equal to, 3.0 Mm-1 visibility impact at 
any MANEVU Class I area; the Ask requests MANEVU states to conduct 
four-factor analyses for the specified sources within their borders. 
This Ask explicitly engages with the statutory and regulatory 
requirement to determine reasonable progress based on the four factors; 
MANEVU considered it ``reasonable to have the greatest contributors to 
visibility impairment conduct a four-factor analysis that would 
determine whether emission control measures should be pursued and what 
would be reasonable for each source.'' \67\
---------------------------------------------------------------------------

    \67\ See ``MANEVU Regional Haze Consultation Report and 
Consultation Documentation--Final.''
---------------------------------------------------------------------------

    As an initial matter, EPA does not generally agree that 3.0 
Mm-1 visibility impact is a reasonable threshold for source 
selection. The RHR recognizes that, due to the nature of regional haze 
visibility impairment, numerous and sometimes relatively small sources 
may need to be selected and evaluated for control measures in order to 
make reasonable progress. See 2021 Clarifications Memo at 4. As 
explained

[[Page 58678]]

in the 2021 Clarifications Memo, while states have discretion to choose 
any source selection threshold that is reasonable, ``[a] state that 
relies on a visibility (or proxy for visibility impact) threshold to 
select sources for four-factor analysis should set the threshold at a 
level that captures a meaningful portion of the state's total 
contribution to visibility impairment to Class I areas.'' 2021 Memo at 
3. In this case, the 3.0 Mm-1 threshold did not identify any 
sources in Connecticut (and identified only 22 across the entire MANEVU 
region), indicating that it may be unreasonably high. We also note, 
however, that the 3.0 Mm-1 threshold used in this Ask is 
only one part of the MANEVU source identification process and that 
being below this threshold did not necessarily exclude a source from 
additional review in connection with another Ask.
    The EPA agrees that Connecticut reasonably determined it has 
satisfied Ask 2. As explained above, while we do not generally agree 
that a 3.0 Mm-1 threshold for selecting sources for four-
factor analysis results in a set of sources the evaluation of which has 
the potential to meaningfully reduce the state's contribution to 
visibility impairment, the MANEVU analysis did not identify any sources 
in Connecticut with an impact at or above 3.0 Mm-1. EPA 
notes that the MANEVU analysis also did not identify any sources in 
Connecticut above 2.0 Mm-1 and only once source above 1 
Mm-1: Bridgeport Harbor Station Unit 3 (at 1.22 
Mm-1),\68\ which permanently retired on May 31, 2021. The 
State of Connecticut has revoked the permit for this unit \69\ and has 
committed funding to assist in demolishing the facility and 
redeveloping the site.\70\
---------------------------------------------------------------------------

    \68\ See 2016 MANEVU CALPUFF Modeling of Large Electrical 
Generating Units and Industrial Sources.
    \69\ See ``Combined NSR & Registration Revocation Letter'' in 
the docket for this rulemaking.
    \70\ See https://www.ctpost.com/news/article/ct-bridgeport-pseg-power-plant-demolition-18388093.php (also in docket for this 
rulemaking).
---------------------------------------------------------------------------

    Ask 3, which addresses the sulfur content of heating oil used in 
MANEVU states, is based on a four-factor analysis for the heating oil 
sulfur reduction regulations contained in that Ask; \71\ specifically, 
for the control strategy of reducing the sulfur content of distillate 
oil to 15 ppm. The analysis started with an assessment of the costs of 
retrofitting refineries to produce 15 ppm heating oil in sufficient 
quantities to support implementation of the standard, as well as the 
impacts of requiring a reduction in sulfur content on consumer prices. 
The analysis noted that, as a result of previous EPA rulemakings to 
reduce the sulfur content of on-road and non-road-fuels to 15 ppm, 
technologies are currently available to achieve sulfur reductions and 
many refiners are already meeting this standard, meaning that the 
capital investments for further reductions in the sulfur content of 
heating oil are expected to be relatively low compared to costs 
incurred in the past. The analysis also examined, by way of example, 
the impacts of New York's existing 15 ppm sulfur requirements on 
heating oil prices and concluded that the cost associated with reducing 
sulfur was relatively small in terms of the absolute price of heating 
oil compared to the magnitude of volatility in crude oil prices. It 
also noted that the slight price premium is compensated by cost savings 
due to the benefits of lower-sulfur fuels in terms of equipment life 
and maintenance and fuel stability. Consideration of the time necessary 
for compliance with a 15 ppm sulfur standard was accomplished through a 
discussion of the amount of time refiners had needed to comply with the 
EPA's on-road and non-road fuel 15 ppm requirement, and the 
implications existing refinery capacity and distribution infrastructure 
may have for compliance times with a 15 ppm heating oil standard. The 
analysis concluded that with phased-in timing for states that have not 
yet adopted a 15 ppm heating oil standard there ``appears to be 
sufficient time to allow refiners to add any additional heating oil 
capacity that may be required.'' \72\ The analysis further noted the 
beneficial energy and non-air quality environmental impacts of a 15 ppm 
sulfur heating oil requirement and that reducing sulfur content may 
also have a salutary impact on the remaining useful life of residential 
furnaces and boilers.\73\
---------------------------------------------------------------------------

    \71\ See 2016 Updates to the Assessment of Reasonable Progress 
For Regional Haze In MANEVU Class I Areas.
    \72\ Id. at 8-7.
    \73\ Id. at 8-8.
---------------------------------------------------------------------------

    The EPA agrees that Connecticut reasonably relied on MANEVU's four-
factor analysis for a low-sulfur fuel oil regulation, which engaged 
with each of the statutory factors and explained how the information 
supported a conclusion that a 15 ppm sulfur fuel oil standard for fuel 
oils is reasonable. As noted above, RCSA 22a-174-19a limits the sulfur 
content of home heating oil to 15 ppm and the sulfur content of off-
road diesel to 3000 ppm (0.3%S). RCSA 22a-174-19b further limits sulfur 
content of fuel oil sold in Connecticut for use in stationary sources 
to 15 ppm for distillate and 3000 ppm (0.3%S) for aviation and residual 
fuels. EPA approved the latest revisions of these rules into 
Connecticut's SIP on May 25, 2016,\74\ and Connecticut includes both in 
its long-term strategy for the second planning period.\75\ 
Connecticut's SIP-approved ultra-low sulfur fuel oil rule is consistent 
with Ask 3's sulfur content standards for the three types of fuel oils 
(distillate oil, #4 residual oil, #6 residual oil). EPA therefore 
agrees that Connecticut satisfied Ask 3.
---------------------------------------------------------------------------

    \74\ 81 FR 33134.
    \75\ See CT RH SIP Submittal at 75.
---------------------------------------------------------------------------

    Connecticut concluded that no additional updates were needed to 
meet Ask 4, which requests that MANEVU states pursue updating permits, 
enforceable agreements, and/or rules to lock-in lower emission rates 
for SO2, NOX and PM at EGUs and other sources 
larger than 250 MMBtu per hour that have switched operations to lower 
emitting fuels. As noted above, Connecticut has asserted that EGUs and 
large sources are already subject to Title V permitting requirements 
under RCSA section 22a-174-33 and that permits for these sources are 
renewed every five years and specify allowable operating scenarios, 
which includes type of fuels fired. Any change in fuel type that is not 
allowed by permit would trigger requirements for a new or modified 
permit under RCSA sections 22a-174-3a and -33, which are in the SIP. 
While requirements for lower emitting fuels contained in state fuel 
sulfur regulations at RCSA sections 22a-174-19a may be a means to 
achieve SO2 reductions at sources covered by this Ask that 
have switched to a lower emitting fuel oil, it is not clear from the 
discussion in Connecticut's submittal what actions the State has 
``pursued'' under this Ask to ``lock-in lower emission rates'' of 
SO2, NOX and PM at other sources covered by the 
Ask (i.e., sources that have switched to other lower emitting fuel 
types). The submittal does not provide specific examples of sources 
previously authorized to burn more than one fuel type that have been 
``locked-in'' to the lower-emitting fuel under this Ask. Satisfaction 
of Ask 4 is not necessarily a required element of a Regional Haze SIP, 
however. In addition, as Connecticut notes, any sources that wish to 
make a future switch to higher emitting fuels not currently authorized 
by permit are required to revise their permits to reflect the change, 
and state rules favor lower-emitting fuels and make any permit revision 
subject to additional analyses, including NSR.
    Ask 5 addresses NOX emissions from peaking combustion 
turbines that have

[[Page 58679]]

the potential to operate on high electric demand days. The Ask requests 
states to ``strive'' for NOX emission standards of no 
greater than 25 ppm for natural gas and 42 ppm for fuel oil but at a 
minimum, meet NOX emissions standards of no greater than 42 
ppm for natural gas and 96 ppm for fuel oil.
    As discussed above, Connecticut identified two recently approved 
regulations in the SIP that address NOX emissions from 
electric generating units and other stationary sources. RCSA section 
22a-174-22e prescribes averaging times and emission limits for units at 
major sources of NOX. As of June 1, 2023, the state 
regulations set limits of 25 ppm for natural gas and 42 ppm for fuel 
oil at combined cycle turbines and 40 ppm for natural gas and 50 ppm 
for fuel oil at simple cycle turbines. The combined cycle limits match 
the ``strive for'' limits in the Ask. And while the simple cycle limits 
do not, they are more stringent than the ``minimum'' limits in the 
Ask.\76\ In addition, RCSA section 22a-174-22f applies to combustion 
turbines at facilities that are not major sources of NOX and 
provides that combustion turbines that meet the generating criterion of 
the Ask (i.e., capable of generating 15 MW or more) are also subject to 
the limits in RCSA section 22a-174-22e. See RCSA section 22a-174-
22f(a)(1), (e)(4). Connecticut includes both regulations in its long-
term strategy for the second planning period,\77\ and both are in the 
SIP. EPA agrees that Connecticut reasonably demonstrated that it meets 
Ask 5.
---------------------------------------------------------------------------

    \76\ See CT RH SIP Submittal, table 5-2.
    \77\ See id. at 75.
---------------------------------------------------------------------------

    Finally, regarding Ask 6, Connecticut pointed to various state 
regulations, State Executive Orders, participation in offshore wind 
projects, and membership in RGGI as policy efforts to increase energy 
efficiency and reduce reliance on fossil fuels for energy. 
Additionally, as discussed in the previous section, Connecticut 
reported energy savings efforts through 2018 have resulted in avoidance 
of the equivalent of one 130 MW power plant. The EPA agrees that 
Connecticut has satisfied Ask 6's request to consider and report in its 
SIP measures or programs related to energy efficiency, cogeneration, 
and other clean distributed generation technologies.
    In sum, the EPA is proposing to find--based on Connecticut's 
participation in the MANEVU planning process, how it has addressed the 
Asks, and the EPA's assessment of Connecticut's emissions and point 
sources--that Connecticut has complied with the requirements of Sec.  
51.308(f)(2)(i). Specifically, Connecticut's application of MANEVU Ask 
3 engages with the requirement that states evaluate and determine the 
emission reduction measures necessary to make reasonable progress by 
considering the four statutory factors.
    The EPA is proposing to find the state's approach meets the 
statutory and regulatory requirements for several reasons. Connecticut 
reasonably evaluated and explained its decision to focus on 
SO2 and NOX to address visibility impairment 
within the MANEVU region. Connecticut adequately supported that 
decision through reasonable reliance on the MANEVU technical analyses 
cited in its submission. In addition, as the EPA discusses in more 
detail in section IV.I. below, Connecticut adequately responded to 
comments to consider sources identified by the FLMs through the 
consultation process. The Agency notes that MANE-VU concluded that 
sulfates from SO2 emissions were still the primary driver of 
visibility impairment in the second implementation period and that 
MANEVU conducted a four-factor analysis to support Ask 3, which 
requests that states pursue ultra-low sulfur fuel oil standards to 
address SO2 emissions. Connecticut's SIP-approved sulfur in 
fuel rule sets stringent limits for sulfur content and SO2 
emissions for fuels. Additionally, Connecticut's SIP submittal 
identifies a long-term strategy that includes five state regulations 
previously approved into its SIP. The provisions at RCSA 22a-174-19a 
control SO2 emissions by limiting the sulfur content of home 
heating oil to 15 ppm and the sulfur content of off-road diesel to 3000 
ppm (0.3%S). RCSA 22a-174-19b further controls SO2 emissions 
by limiting sulfur content of fuel oil sold in Connecticut for use in 
stationary sources to 15 ppm for distillate and 3000 ppm (0.3%S) for 
aviation and residual fuels. EPA approved the latest revisions of these 
rules into Connecticut's SIP on May 25, 2016.\78\ Connecticut's 
regulations at RCSA 22a-174-22e and RCSA 22a-174-22f prescribe 
averaging times and set emission limits for sources of NOX 
at 25 ppm for natural gas and 42 ppm for fuel oil at combined cycle 
turbines and at 40 ppm for natural gas and 50 ppm for fuel oil at 
simple cycle turbines. EPA most recently approved these regulations 
into Connecticut's SIP on July 14, 2021, and July 31, 2017, 
respectively.\79\ Further, RCSA 22a-174-38, most recently approved into 
Connecticut's SIP on July 31, 2017,\80\ regulates NOX 
emissions from municipal waste combustors.
---------------------------------------------------------------------------

    \78\ 81 FR 33134.
    \79\ 86 FR 37053; 82 FR 35454.
    \80\ 82 FR 35454.
---------------------------------------------------------------------------

    The EPA also notes the relatively low impact Connecticut's 
emissions have on the visibility impairment in nearby Class 1 areas. 
While, as discussed earlier, we do not necessarily agree with the level 
of the State's chosen 2% contribution threshold, it appears that 
emissions from Connecticut have relatively small contributions to Class 
I areas.\81\ Further, Connecticut is in the Ozone Transport Region and 
is currently designated nonattainment statewide for both the 2008 and 
2015 ozone standards. As a result, Connecticut already imposes 
stringent controls on its sources, including through statewide 
Reasonably Available Control Technology (RACT) requirements, to limit 
emissions of the ozone precursors NOX and VOCs. In addition, 
Connecticut must continue to control emissions of these precursors to 
attain, and then maintain, the ozone standards. As NOX and 
VOCs are also contributors to visibility impairment, these requirements 
have had the additional effect of controlling haze-forming emissions 
from sources throughout the State and are generally reflected in the 
MANEVU contribution screening results. Based on the MANEVU contribution 
screening analysis, Connecticut's highest percent mass-weighted sulfate 
and nitrate contribution to any Class I area is estimated to be 1.4% at 
Moosehorn Wilderness and Roosevelt Campobello International Park, and 
1.3% and 1.2% to Acadia National Park and the Lye Brook Wilderness 
Area, respectively.\82\ Slightly lower percent contributions are 
estimated from Connecticut's emissions to the other Class I areas in 
the MANEVU states: 1.0% to the Brigantine Wilderness Area and 0.7% to 
the two New Hampshire Wilderness Areas.\83\ As discussed earlier, 
Connecticut's submittal includes and adopts a four-factor analysis 
conducted by the MANEVU states to support low-sulfur fuel restrictions 
that Connecticut has included in its long-term strategy. EPA believes 
it was reasonable for Connecticut not to conduct additional four-factor 
analyses in this case because haze-forming emissions from the State are 
already limited by EPA-approved emissions limits in the SIP (as a 
result of other CAA requirements), there are no other large visibility 
impairing point sources of SO2 or NOX in the 
State, and the State's overall small contributions to

[[Page 58680]]

visibility impairment in nearby Class I areas.
---------------------------------------------------------------------------

    \81\ See CT RH Submittal at 19-27, 46.
    \82\ See table 4-1 of the CT RH SIP.
    \83\ See id.
---------------------------------------------------------------------------

    For the above reasons, the EPA proposes to find that Connecticut's 
SIP submittal satisfies the requirements that a State submit a long-
term strategy that addresses regional haze visibility impairment for 
each mandatory Class I Federal area that may be affected by emissions 
from the State and that the long-term strategy include the emission 
reduction measures that are necessary to make reasonable progress 
determined by considering the four factors.
c. Additional Long-Term Strategy Requirements
    The consultation requirements of Sec.  51.308(f)(2)(ii) provide 
that states must consult with other states that are reasonably 
anticipated to contribute to visibility impairment in a Class I area to 
develop coordinated emission management strategies containing the 
emission reductions measures that are necessary to make reasonable 
progress. 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, respectively. Section 51.308(f)(2)(ii)(C) speaks to what 
happens if states cannot agree on what measures are necessary to make 
reasonable progress.
    Connecticut participated in and provided documentation of the 
MANEVU intra- and inter-RPO consultation processes, which included 
consulting with both MANEVU and non-MANEVU states about emissions from 
Connecticut reasonably anticipated to contribute to visibility 
impairment in Class I areas within the MANEVU area and in adjacent 
areas. The consultations addressed developing coordinated emission 
management strategies containing the emission reductions necessary to 
make reasonable progress at the Class I areas impacted by emissions 
from States within MANEVU. Connecticut addressed the MANEVU Asks by 
providing information on the enforceable measures it has in place that 
satisfy each Ask.\84\ While Connecticut did not receive any requests 
from non-MANEVU states to consider additional measures to address 
visibility impairment in Class I areas outside MANEVU, MANEVU 
documented disagreements that occurred during consultation. For 
instance, MANEVU noted in its Consultation Report that upwind states 
expressed concern regarding the analyses the RPO utilized for the 
selection of states for the consultation. MANEVU agreed that these 
tools, as all models, have their limitations, but nonetheless deemed 
them appropriate. Additionally, there were several comments regarding 
the choice of the 2011 modeling base year. MANEVU agreed that the 
choice of base year is critical to the outcome of the study. MANEVU 
acknowledged that there were newer versions of the emission inventories 
and the need to use the best available inventory for each analysis. 
MANEVU, however, concluded that the selected inventories were 
appropriate for the analysis. Additionally, upwind states noted that 
they would not be able to address the MANEVU Asks until they finalize 
their SIPs. MANEVU believed the assumption of the implementation of the 
Asks from upwind states in its 2028 control case modeling was 
reasonable, and Connecticut included both the 2028 base case and 
control case modeling results in its SIP, representing visibility 
conditions at the Class 1 areas in the MANU-VU States assuming upwind 
states do not and do implement the Asks, respectively.
---------------------------------------------------------------------------

    \84\ See ``MANEVU Regional Haze Consultation Report.''
---------------------------------------------------------------------------

    In sum, Connecticut participated in the MANEVU intra- and inter-RPO 
consultation and included in its SIP submittal the measures identified 
and agreed to during those consultations, thereby satisfying Sec.  
51.308(f)(2)(ii)(A) and (B). Connecticut satisfied Sec.  
51.308(f)(2)(ii)(C) by participating in MANEVU's consultation process, 
which documented the disagreements between the upwind states and MANEVU 
and explained MANEVU's reasoning on each of the disputed issues. Based 
on the entirety of MANEVU's intra- and inter-RPO consultation and 
MANEVU's and Connecticut's responses to comments on the SIP submission 
and various technical analyses therein, we propose to determine that 
Connecticut has satisfied the consultation requirements of Sec.  
51.308(f)(2)(ii).
    The documentation requirement of Sec.  51.308(f)(2)(iii) provides 
that states may meet their obligations to document the technical bases 
on which they are relying to determine the emission reductions measures 
that are necessary to make reasonable progress through an RPO, as long 
as the process has been ``approved by all State participants.'' As 
explained above, Connecticut chose to rely on MANEVU's technical 
information, modeling, and analysis to support development of its long-
term strategy. The MANEVU technical analyses on which Connecticut 
relied are listed in the state's SIP submission and include source 
contribution assessments, information on each of the four factors and 
visibility modeling information for certain EGUs, and evaluations of 
emission reduction strategies for specific source categories. 
Connecticut also provided additional information to further demonstrate 
the technical bases and emission information it relied on to determine 
the emission reductions measures that are necessary to make reasonable 
progress. Based on the documentation provided by the state, we propose 
to find Connecticut satisfies this requirement of Sec.  
51.308(f)(2)(iii).
    Section 51.308(f)(2)(iii) also requires that the emissions 
information considered to determine the measures that are necessary to 
make reasonable progress include information on emissions for the most 
recent year for which the state has submitted triennial emissions data 
to the EPA (or a more recent year), with a 12-month exemption period 
for newly submitted data. Connecticut's SIP submission included 2017 
NEI emission data for NOX, SO2, PM, VOCs and 
NH3 and 2017 Air Markets Program Data (AMPD) emissions for 
NOX and SO2. Based on Connecticut's consideration 
and analysis of the 2017 and 2019 emission data in its SIP submittal, 
the EPA proposes to find that Connecticut has satisfied the emissions 
information requirement in Sec.  51.308(f)(2)(iii).
    We also propose to find that Connecticut reasonably considered the 
five additional factors in Sec.  51.308(f)(2)(iv) in developing its 
long-term strategy. Pursuant to Sec.  51.308(f)(2)(iv)(A), Connecticut 
noted that existing and ongoing state and federal emission control 
programs that contribute to emission reductions through 2028 would 
impact emissions of visibility impairing pollutants from point and 
nonpoint sources in the second implementation period. Connecticut 
included in its SIP a comprehensive lists of control measures and other 
requirements that will continue to reduce emissions of visibility 
impairing pollutants, identifying the source category and corresponding 
Connecticut regulatory provisions. These measures include SIP approved 
revisions to RCSA section 22a-174-38 (82 FR 35454) to obtain 
NOX emission reductions from municipal waste combustors; 
implementation of RCSA sections 22a-174-22e (86 FR 37053) and 22a-174-
22f (82 FR 35454) to obtain NOX emissions from major and 
minor sources of NOX; and implementation of the last phase 
of RCSA section 22a-174-19b (81 FR 33134) to reduce sulfur oxide 
emissions from fuel burning sources.

[[Page 58681]]

    Connecticut's consideration of measures to mitigate the impacts of 
construction activities as required by Sec.  51.308(f)(2)(iv)(B) 
includes, in section 8.2 of its SIP submission, measures that 
Connecticut has implemented to mitigate the impacts from such 
activities. Connecticut has implemented standards that reduce fugitive 
dust emissions from construction, rules to address exhaust emissions 
including rules to limit the idling of vehicles and equipment, rules to 
reduce allowable smoke from on-road diesel engines, and general 
conformity rules.
    Pursuant to Sec.  51.308(f)(2)(iv)(C), source retirements and 
replacement schedules are addressed in section 8.3 of Connecticut's 
submission. Source retirements and replacements were considered in 
developing the 2028 emission projections, with on the books/on the way 
retirements and replacements included in the 2028 projections. The EGU 
point sources included in the inventories used in the MANEVU 
contribution assessment and that were subsequently retired are 
described in section 8.3 of the Connecticut submission. Connecticut 
calculated a net reduction of approximately 8,990 tons per year (tpy) 
of allowable NOX emissions and 17,350 tpy of allowable 
SO2 emissions between the 2011 base year and the 2028 
projected year based on EGU retirements (including retirement of the 
last coal-fired unit in the state) and replacement during that time 
with lower emitting units.
    In considering smoke management as required in 40 CFR 
51.308(f)(2)(iv)(D), Connecticut explained, in section 8.4 of its 
submission, that it addresses smoke management through a program under 
state law at CGS section 22a-174(f) that authorizes open burning 
(including prescribed burns for agriculture and wildland vegetation 
management purposes) through permits issued by municipal officials but 
limits it on poor air quality days, thereby reducing the impacts of 
prescribed burns on visibility. EPA approved this program into 
Connecticut's SIP on September 1, 2016. 81 FR 60274. Connecticut 
considers these efforts to be sufficient to protect visibility in Class 
I areas, including from agriculture- and forestry-related smoke. The 
EPA agrees that Connecticut adequately considered smoke management 
practices as part of its submittal as required by Sec.  
51.308(f)(2)(iv)(D).
    Connecticut considered the anticipated net effect of projected 
changes in emissions as required by Sec.  51.308(f)(2)(iv)(E) by 
discussing, in section 8.1 of its submission, various programs and 
state regulations that control emissions from the State's point, area, 
and mobile sources. Connecticut, through its nonattainment status for 
the 2008 and 2015 ozone National Ambient Air Quality Standards, is 
required to implement programs to reduce vehicle miles traveled (VMTs), 
which will reduce emissions in the mobile source sector. This sector 
also contributes to regional haze, so any reductions would have the 
added benefit of helping to improve visibility. Additionally, section 6 
of the Connecticut submittal contains emissions projections for 2028, 
modeled in collaboration with MANEVU. These projected emissions 
incorporate the impact of strategies that are on-the-books, anticipated 
growth in the respective sector, and anticipated unit closures and the 
MANEVU ``Ask.'' The 2028 inventory projections demonstrate an overall 
reduction in emissions between the 2011 base year and 2028 modeled year 
thus, satisfying (f)(2)(iv)(e).
    Because Connecticut has reasonably considered each of the five 
additional factors, the EPA proposes to find that Connecticut has 
satisfied the requirements of 40 CFR 51.308(f)(2)(iv).

F. Reasonable Progress Goals

    Section 51.308(f)(3) contains the requirements pertaining to RPGs 
for each Class I area. Because Connecticut does not host a Class I 
area, it is not subject to either Sec.  51.308(f)(3)(i) or 
51.308(f)(3)(ii)(A). 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 
glidepath, the upwind state must provide the same demonstration.
    None of the Class I areas in or adjacent to the MANEVU region have 
RPGs above their respective URP glidepath. Table 2-1 of Connecticut's 
SIP submittal summarizes baseline visibility conditions (i.e., 
visibility conditions during 2000-2004) for the most impaired and 
clearest days at each area as well as information on natural visibility 
conditions. Table 2-3 of the submittal shows the values on the URP 
glidepaths for 2028. Figures 7-1 and 7-2 summarize the 2028 RPG for the 
most impaired days for each area, as well as the modeled 2028 base case 
(representing visibility conditions in 2028 with existing controls), 
respectively. These visibility conditions, as well as the 2028 
reasonable progress goals for the clearest days, are also included. The 
2028 RPGs for each Class I area are well below their respective URP 
glidepaths. Therefore, Sec.  51.308(f)(3)(ii)(B) is not applicable to 
Connecticut.

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. Since Connecticut does not contain any Class I 
areas, it is not required to submit the monitoring strategy referenced 
in Sec.  51.308(f)(6), nor are the requirements in Sec.  
51.308(f)(6)(i), (ii), and (iv) applicable.
    40 CFR 51.308(f)(6)(iii), however, applies to states with no Class 
I areas (such as Connecticut) and requires them to include in their 
Regional Haze SIPs procedures by which monitoring data and other 
information are used in determining the contribution of emissions from 
within the state to visibility impairment at Class I areas in other 
states. Monitoring in Connecticut that contributes data for assessing 
visibility is described in section 2.1 of the Connecticut SIP 
submission.\85\ Visibility data analysis procedures are described in 
the MANEVU visibility data report. Other procedures and data used for 
determining Connecticut contribution to visibility impairment are 
described in section 4 of the Connecticut SIP and the MANEVU documents 
referenced.\86\ An IMPROVE monitor at the Mohawk Mountain site in 
Connecticut provides data to assess current visibility, track changes 
in visibility, and help determine the causes of visibility impairment 
in Class I areas in the region.
---------------------------------------------------------------------------

    \85\ Connecticut's submission contains two sections identified 
as 2.1. The first one discusses the IMPROVE monitoring network.
    \86\ Mid-Atlantic/Northeast U.S. Visibility Data, 2004-2019 (2nd 
RH SIP Metrics).
---------------------------------------------------------------------------

    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. Connecticut provides for emissions inventories 
and estimates for future projected emissions by participating in the 
MANEVU RPO and complying with EPA's Air Emissions Reporting Rule 
(AERR). In 40 CFR part 51, subpart A, the AERR requires states to 
submit updated

[[Page 58682]]

emissions inventories for criteria pollutants to EPA's Emissions 
Inventory System (EIS) every three years. The emission inventory data 
are used to develop the NEI, which provides for, among other things, a 
triennial state-wide inventory of pollutants that are reasonably 
anticipated to cause or contribute to visibility impairment.
    Section 3 of Connecticut's submission includes tables of NEI data. 
The source categories of the emissions inventories included are: (1) 
Point sources, (2) nonpoint sources, (3) non-road mobile sources, and 
(4) on-road mobile sources. The point source category is further 
divided into AMPD point sources and non-AMPD point sources. Connecticut 
included NEI emissions inventories for the following years: 2002 (one 
of the regional haze program baseline years), 2008, 2011, 2014, and 
2017; and for the following pollutants: SO2, NOX, 
PM10, PM2.5, VOCs, and NH3.
    Section 51.308(f)(6)(v) also requires states to include estimates 
of future projected emissions and include a commitment to update the 
inventory periodically. Connecticut relied on the MANEVU 2028 emissions 
projections for MANEVU states. MANEVU completed two 2028 projected 
emissions modeling cases--a 2028 base case that considers only on-the-
books controls and a 2028 control case that considers implementation of 
the MANEVU Asks.\87\
---------------------------------------------------------------------------

    \87\ See ``OTC MANEVU 2011 Based Modeling Platform Support 
Document October 2018--Final.''
---------------------------------------------------------------------------

    The EPA proposes to find that Connecticut has met the requirements 
of 40 CFR 51.308(f)(6) as described above, including through its 
continued participation in the MANEVU RPO and its on-going compliance 
with the AERR, and that no further elements are necessary at this time 
for Connecticut to assess and report on visibility pursuant to 40 CFR 
51.308(f)(6)(vi). Connecticut's SIP submittal also includes a 
commitment to update the statewide emissions inventory periodically.

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 
any 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, 
Sec.  51.308(g)(5), which also applies to all states, requires an 
assessment of any significant changes in anthropogenic emissions within 
or outside the state that have occurred since the period addressed by 
the first implementation period progress report, including whether such 
changes were anticipated and whether they have limited or impeded 
expected progress towards reducing emissions and improving visibility.
    Connecticut's submission describes the status of measures of the 
long-term strategy from the first implementation period.\88\ As a 
member of MANEVU, Connecticut considered the MANEVU Asks and adopted 
corresponding measures into its long-term strategy for the first 
implementation period. The MANEVU Asks were: (1) Timely implementation 
of Best Available Retrofit Technology (BART) requirements; (2) EGU 
controls including Controls at 167 Key Sources that most affect MANEVU 
Class I areas; (3) Low sulfur fuel oil strategy; and (4) Continued 
evaluation of other control measures. Connecticut met all the 
identified reasonable measures requested during the first 
implementation period. During the first planning period for regional 
haze, programs that were put in place focused on reducing 
SO2 emissions. The reductions achieved led to vast 
improvements in visibility at the MANEVU Federal Class I Areas due to 
reduced sulfates formed from SO2 emissions. Connecticut 
describes the control measures that help control the emissions of VOCs, 
NOX, PM and SO2 from a wide range of sources in 
the SIP submission and identifies BART and Alternative to BART 
requirements in section 5.5. The submission also includes periodic 
emission data that demonstrate a decrease in VOCs, NOX, PM 
and SO2 emissions throughout the state.\89\
---------------------------------------------------------------------------

    \88\ See section 5.5 of the CT RH SIP.
    \89\ See section 3 of the CT RH SIP.
---------------------------------------------------------------------------

    The EPA proposes to find that Connecticut has met the requirements 
of 40 CFR 51.308(g)(1) and (2) because its SIP submission describes the 
measures included in the long-term strategy from the first 
implementation period, as well as the status of their implementation 
and the emission reductions achieved through such implementation.
    Pursuant to Sec.  51.308(g)(4), in section 3 of its submittal, 
Connecticut provided a summary of emissions of NOX, 
SO2, PM10, PM2.5, VOCs, and 
NH3 from all sources and activities, including from point, 
nonpoint, non-road mobile, and on-road mobile sources, for the time 
period from 2002 to 2017. With respect to sources that report directly 
to the EPA, Connecticut also included AMPD state summary data for 
SO2 and NOX emissions for 2018 and 2019.
    The reductions achieved by Connecticut emission control measures 
are seen in the emissions inventory. Based on Connecticut's SIP 
submission, NOX emissions have steadily declined in 
Connecticut from 2002 through 2017, especially in the point, nonroad 
and onroad mobile sectors. NOX emissions are expected to 
continue to decrease as fleet turnover occurs and the older more 
polluting vehicles and equipment are replaced by newer, cleaner ones. 
Emissions of SO2 have shown a decline of 93% in Connecticut 
over the period 2002 to 2017. Connecticut attributes the reductions in 
point emissions to fuel switching from coal and oil to natural gas, 
federal and state low sulfur fuel regulations, NOX budget 
and successor programs for power plants and the retirement of older 
units as well as improved controls on new units. Since some components 
of the MANEVU low sulfur fuel strategy were not implemented until 2018, 
and as MANEVU states continue to adopt rules to implement the strategy, 
additional SO2 emissions reductions are expected to continue 
into the future.
    Table 3-11 of Connecticut's submission shows VOC emissions from all 
NEI data categories for the period 2002 to 2017 in Connecticut. VOC 
emissions have shown a steady decline in Connecticut over this period. 
VOC

[[Page 58683]]

decreases were achieved in all sectors due to Federal new engine 
standards for onroad and nonroad vehicles and equipment, the National 
and State low emission vehicle programs, SIP-approved area source rules 
such as consumer products, portable fuel containers, paints, autobody 
refinishing, asphalt paving applications, and solvent cleaning 
operations, and VOC storage tank rules.
    In Connecticut's submission, table 3-14 shows a summary of 
PM10 emissions from all NEI data categories point, nonpoint, 
non-road, and onroad for the period from 2002 to 2017 in Connecticut. 
In Connecticut, PM10 emissions steadily decreased in the 
point, nonpoint, and nonroad categories for the period from 2002 to 
2017. The apparent increase in the onroad emissions is due to changes 
in emission inventory calculation methodologies, which resulted in 
higher particulate matter estimates. The variation in emissions in the 
nonpoint category is due to changes in calculation methodologies for 
residential wood burning and fugitive dust categories, which have 
varied significantly.
    Table 3-17 of Connecticut's submission shows a summary of 
PM2.5 emissions from all NEI data categories for the period 
from 2002 to 2017 in Connecticut. PM2.5 emissions steadily 
decreased in the nonroad category for the period from 2002 to 2014. 
Most reductions came from the nonpoint category, which experienced 
periodic variation in emissions due to changes in calculation 
methodologies for residential wood burning and fugitive dust 
categories. The decrease in nonroad PM2.5 emissions can 
likely be attributed to new Federal engine standards for nonroad 
vehicles and equipment.\90\ Similarly, an overall decrease in onroad 
emissions can be attributed to Federal and State vehicle regulations 
and standards, which impose increasingly tighter emissions limits with 
incremental model year vehicles.\91\ The increase in emissions in the 
onroad category from 2002 to 2008 is due to changes in emission 
inventory calculation methodologies and a model change, as previously 
explained, which resulted in higher fine particulate matter estimates.
---------------------------------------------------------------------------

    \90\ See https://www.epa.gov/emission-standards-reference-guide/epa-emission-standards-nonroad-engines-and-vehicles for info on the 
EPA's nonroad engine programs.
    \91\ See 80 FR 13768.
---------------------------------------------------------------------------

    Table 3-20 of Connecticut's submission shows ammonia 
(NH3) emissions from all NEI data categories for the period 
2002 to 2017 in Connecticut. Though ammonia decreases were achieved in 
the onroad sector due to Federal new engine standards for vehicles and 
equipment, increases and decreases from 2002 to 2017 in the other 
categories are due to reporting, grouping and methodology changes. 
There was little change to nonroad ammonia emissions. Overall, ammonia 
emissions have decreased from 2008 to 2017.
    The EPA is proposing to find that Connecticut has satisfied the 
requirements of Sec.  51.308(g)(4) by providing emissions information 
for NOX, SO2, PM10, PM2.5, 
VOCs, and NH3 broken down by type of source.
    Connecticut uses the emissions trend data in the SIP submission to 
support the assessment that anthropogenic haze-causing pollutant 
emissions in Connecticut have decreased during the reporting period and 
that changes in emissions have not limited or impeded progress in 
reducing pollutant emissions and improving visibility. The data 
Connecticut presents for NOX, SO2, VOCs, 
PM10, PM2.5, and NH3 show consistently 
declining emissions of those pollutants. The EPA is proposing to find 
that Connecticut has met the requirements of Sec.  51.308(g)(5).

I. Requirements for State and Federal Land Manager Coordination

    Section 169A(d) of the CAA requires states to consult with FLMs 
before holding the public hearing on a proposed regional haze SIP, and 
to include a summary of the FLMs' conclusions and recommendations in 
the notice to the public. In addition, Sec.  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, 
but 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 requires that the consultation include 
the opportunity for the FLMs to discuss their assessment of visibility 
impairment in any Class I area and their 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.
    The states in the MANEVU RPO conducted FLM consultation early in 
the planning process concurrent with the state-to-state consultation 
that formed the basis of the RPO's decision making process. As part of 
the consultation, the FLMs were given the opportunity to review and 
comment on the technical documents developed by MANE-VU. The FLMs were 
invited to attend the intra- and inter-RPO consultations calls among 
states and at least one FLM representative was documented to have 
attended seven intra-RPO meetings and all inter-RPO meetings. 
Connecticut participated in these consultation meetings and calls.\92\
---------------------------------------------------------------------------

    \92\ See ``MANEVU Regional Haze Consultation Report and 
Consultation Documentation--Final.''
---------------------------------------------------------------------------

    As part of this early engagement with the FLMs, on April 12, 2018, 
the NPS sent letters to the MANEVU states requesting that they consider 
specific individual sources in their long-term strategies.\93\ NPS used 
an analysis of emissions divided by distance (Q/d) to estimate the 
impact of MANEVU facilities. To select the facilities, NPS first summed 
2014 NEI NOX, PM10, SO2, and 
SO4 emissions and divided by the distance to a specified NPS 
mandatory Class I Federal area. NPS summed the Q/d values across all 
MANEVU states relative to Acadia, Mammoth Cave, and Shenandoah National 
Parks, ranked the Q/d values relative to each Class I area, created a 
running total, and identified those facilities contributing to 80% of 
the total impact at each NPS Class I area. NPS applied a similar 
process to facilities in Maine but relative to just Acadia National 
Park. NPS merged the resulting lists of facilities and sorted them by 
their states. NPS suggested that a state consider those facilities 
comprising 80% of the Q/d total, not to exceed the 25 top ranked 
facilities. The NPS identified nine facilities in Connecticut in this 
letter.\94\ Connecticut addressed the NPS initial letter in section 5.4 
of its proposed SIP. Connecticut explained that five of the facilities 
are municipal waste combustors that became subject to more stringent 
NOX and ammonia limits in 2017 through the implementation of 
SIP-approved RCSA 22a-174-38 (82 FR 35454) and whose emissions have, as 
a result, been reduced from the levels the NPS noted in its initial 
letter.\95\ In addition, units at four of the other facilities became 
subject to more

[[Page 58684]]

stringent NOX limits in 2023 through the implementation of 
RCSA 22a-174-22e, which is also in Connecticut's SIP (86 FR 37053).\96\ 
Further, the coal-burning unit at one of these latter facilities 
retired in 2021 (that is, Bridgeport Harbor Unit 3),\97\ and, as noted 
earlier, DEEP revoked the permit. Finally, DEEP explained that the 
Cromwell compressor station has also reduced its emissions from those 
noted by the NPS for this facility.\98\ In 2019, the facility replaced 
several engines with more efficient and lower-emitting turbines that 
are subject to the NOX emission limits in RCSA 22a-174-22e 
that meet the ``strive for'' limits in Ask 5 (i.e., 25 
ppmvd).99 100 This facility is located in a severe 
nonattainment area and was issued a New Source Review permit for the 
new turbines.
---------------------------------------------------------------------------

    \93\ Id.
    \94\ Id.
    \95\ Connecticut RH Submittal at 53-55.
    \96\ Id.
    \97\ Id. at 54-55.
    \98\ Id. at 55 (table 5-3).
    \99\ Id.
    \100\ The permit restricts these turbines to a ppmvd 
NOX emission limit, well below the ``strive for'' limits 
of Ask 5.
---------------------------------------------------------------------------

    On January 15, 2020, Connecticut sent the proposed SIP, including 
the above explanations of how it addressed the FLM comments, to 
representatives of the NPS, the U.S. Forest Service (USFS), and the 
U.S. Fish and Wildlife Service for a 60-day review and comment period 
pursuant to 40 CFR 51.308(i)(2) before making it available for public 
comment. Connecticut received comments from the NPS and the USFS. 
Connecticut included responses to the comments in appendix A of its 
submission to EPA, in accordance with Sec.  51.308(i)(3). In its 
comments, the NPS requested that the State consider 4 municipal waste 
combustors (MWCs) for four-factor analysis. In response to NPS's 
request, Connecticut again noted that MWCs in the State are already 
subject to SIP approved 22a-174-38. Connecticut also noted that the 
state is currently in nonattainment for both the 2008 and 2015 ozone 
standards and is required to impose RACT and obtain emission reductions 
of ozone precursors of not less than 3% per year in order to attain the 
ozone standards. Related to the RACT requirement, CT DEEP explained 
that it actively participates in an Ozone Transport Commission (OTC) 
workgroup to evaluate and compare emissions from MWCs and pursue more 
stringent regulation of their NOX emissions. CT DEEP 
explained that the State has already committed in its RACT SIP to act 
on the information compiled by this workgroup and adhere to the 
resultant OTC recommendations for MWC emission limits.\101\ CT DEEP 
also responded to comments from the USFS regarding three EGUs.\102\
---------------------------------------------------------------------------

    \101\ See Appendix A--Summary of Comments from U.S. 
Environmental Protection Agency and Federal Land Managers (FLMs) 
with Responses from the Department.
    \102\ Id.
---------------------------------------------------------------------------

    On December 3, 2020, CT DEEP issued a notice of public hearing and 
comment and the availability of the draft Regional Haze SIP revision 
for 2018-2028 on CT DEEP's Public Notices and Hearings web page. The 
document announced the opportunity to submit written comments until 
January 29, 2021, as well as a public hearing proposed for January 29, 
2021, provided such hearing was requested. No such request was 
received, and the hearing was cancelled. The Connecticut SIP submittal 
contains the public comments received and CT DEEP's responses, 
including responses to additional comments received from the NPS during 
the public comment period.
    For the reasons stated above, the EPA proposes to find that 
Connecticut has satisfied the requirements under 40 CFR 51.308(i) to 
consult with the FLMs on its regional haze SIP for the second 
implementation period.

J. Other Required Commitments

    Connecticut's January 5, 2022, SIP submission includes a commitment 
to revise and submit a regional haze SIP in 2028, and every ten years 
thereafter. The state's commitment includes submitting periodic 
progress reports in accordance with Sec.  51.308(f) and a commitment to 
evaluate progress towards the reasonable progress goal for each 
mandatory Class I Federal area located within the state and in each 
mandatory Class I Federal area located outside the state that may be 
affected by emissions from within the state in accordance with Sec.  
51.308(g).

V. Proposed Action

    The EPA is proposing to approve the ``Connecticut Regional Haze 
State Implementation Plan Revision Second Planning Period (2018-
2028)'', Final Submittal dated November 2021 and submitted to EPA on 
January 5, 2022, as satisfying the regional haze requirements for the 
second implementation period contained in 40 CFR 51.308(f), (g), and 
(i).

VI. Statutory and Executive Order Reviews

    Under the CAA, the Administrator is required to approve a SIP 
submission that complies with the provisions of the CAA and applicable 
Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in 
reviewing SIP submissions, EPA's role is to approve state choices, 
provided that they meet the criteria of the CAA. Accordingly, this 
action merely proposes to approve state law as meeting Federal 
requirements and does not impose additional requirements beyond those 
imposed by state law. For that reason, this proposed action:
     Is not a ``significant regulatory action'' subject to 
review by the Office of Management and Budget under Executive Orders 
12866 (58 FR 51735, October 4, 1993) and 13563 (76 FR 3821, January 21, 
2011);
     Does not impose an information collection burden under the 
provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.);
     Is certified as not having a significant economic impact 
on a substantial number of small entities under the Regulatory 
Flexibility Act (5 U.S.C. 601 et seq.);
     Does not contain any unfunded mandate or significantly or 
uniquely affect small governments, as described in the Unfunded 
Mandates Reform Act of 1995 (Pub. L. 104-4);
     Does not have Federalism implications as specified in 
Executive Order 13132 (64 FR 43255, August 10, 1999);
     Is not an economically significant regulatory action based 
on health or safety risks subject to Executive Order 13045 (62 FR 
19885, April 23, 1997);
     Is not a significant regulatory action subject to 
Executive Order 13211 (66 FR 28355, May 22, 2001); and
     Is not subject to requirements of section 12(d) of the 
National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 
note) because application of those requirements would be inconsistent 
with the CAA.
    In addition, this proposed rulemaking action, pertaining to 
Connecticut regional haze SIP submission for the second planning 
period, is not approved to apply on any Indian reservation land or in 
any other area where the EPA or an Indian tribe has demonstrated that a 
tribe has jurisdiction. In those areas of Indian country, the rule does 
not have tribal implications and will not impose substantial direct 
costs on tribal governments or preempt tribal law as specified by 
Executive Order 13175 (65 FR 67249, November 9, 2000).
    Executive Order 12898 (Federal Actions To Address Environmental 
Justice in Minority Populations and Low-Income Populations, 59 FR 7629, 
Feb. 16, 1994) directs Federal agencies to identify and address 
``disproportionately high and adverse human health or environmental 
effects'' of their actions on minority populations

[[Page 58685]]

and low-income populations to the greatest extent practicable and 
permitted by law. EPA defines environmental justice (EJ) as ``the fair 
treatment and meaningful involvement of all people regardless of race, 
color, national origin, or income with respect to the development, 
implementation, and enforcement of environmental laws, regulations, and 
policies.'' EPA further defines the term fair treatment to mean that 
``no group of people should bear a disproportionate burden of 
environmental harms and risks, including those resulting from the 
negative environmental consequences of industrial, governmental, and 
commercial operations or programs and policies.'' The air agency did 
not evaluate environmental justice considerations as part of its SIP 
submittal; the CAA and applicable implementing regulations neither 
prohibit nor require such an evaluation. EPA did not perform an EJ 
analysis and did not consider EJ in this action. Consideration of EJ is 
not required as part of this action, and there is no information in the 
record inconsistent with the stated goal of E.O. 12898 of achieving 
environmental justice for people of color, low-income populations, and 
Indigenous peoples.

List of Subjects in 40 CFR Part 52

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

    Dated: July 15, 2024.
David Cash,
Regional Administrator, Region 1.
[FR Doc. 2024-15857 Filed 7-18-24; 8:45 am]
BILLING CODE 6560-50-P