The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments using a method listed under the ADDRESSES section. Include “Docket No. FAA-2025-5026; Project Identifier MCAI-2024-00168-R” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments.

Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to regulations.gov, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM.

CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Eric Rivera, Aviation Safety Engineer, FAA, 1600 Stewart Avenue, Suite 410, Westbury, NY 11590. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

EASA, which is the Technical Agent for the Member States of the European Union, has issued EASA AD 2024-0063, dated March 7, 2024 (EASA AD 2024-0063) (also referred to as the MCAI), to correct an unsafe condition on Airbus Helicopters Model H160 B helicopters. The MCAI states that during a maintenance operation, several self-locking nuts of the window jettisoning system could be loosened by hand. The MCAI further states that the function of these nuts is to hold the threaded axis and the associated cable tightly together, as part of the passenger window jettisoning system. The MCAI also states that certain cable kits which are part of the window jettisoning system may not be in conformance with applicable specifications.

The FAA is proposing this AD to prevent failure of the jettisoning function of the window which, if not addressed, could result in the inability to evacuate helicopter occupants during an emergency situation.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2025-5026.

The FAA reviewed EASA AD 2024-0063, which specifies procedures for replacing each affected passenger window with a serviceable window or modifying an affected window into a serviceable window, which consists of removing and installing a certain part-numbered cable kit. EASA AD 2024-0063 also prohibits installing an affected window or an affected door on any helicopter.

This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

These products have been approved by the civil aviation authority (CAA) of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI. The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.

This proposed AD would require accomplishing the actions specified in EASA AD 2024-0063, described previously, as incorporated by reference, except for any exceptions identified in the regulatory text of this proposed AD.

In the FAA's ongoing efforts to improve the efficiency of the AD process, the FAA developed a process to use some CAA ADs as the primary source of information for compliance with requirements for corresponding FAA ADs. The FAA has been coordinating this process with manufacturers and CAAs. As a result, EASA AD 2024-0063 is proposed for incorporation by reference in this proposed AD. This proposed AD requires compliance with EASA AD 2024-0063 in its entirety through that incorporation, except for any differences identified as exceptions in the regulatory text of this proposed AD. Using common terms that are the same as the heading of a particular section in EASA AD 2024-0063 does not mean that operators need comply only with that section. For example, where the AD requirement refers to “all required actions and compliance times,” compliance with this proposed AD requirement is not limited to the section titled “Required Action(s) and Compliance Time(s)” in EASA AD 2024-0063. Material required by EASA AD 2024-0063 for compliance will be available at regulations.gov under Docket No. FAA-2025-5026 after the final rule is published.

The FAA estimates that this AD, if adopted as proposed, would affect 12 helicopters of U.S. registry. The FAA estimates the following costs to comply with this proposed AD.

The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators.

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

The FAA determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify this proposed regulation:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Would not affect intrastate aviation in Alaska, and

(3) Would not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

The Postal Service is proposing to implement labeling list changes for SCF letters, flats, and parcels to align with its shape-based network updates.

The Postal Service is proposing to implement these changes effective February 1, 2026.

Although exempt from the notice and comment requirements of the Administrative Procedure Act (5 U.S.C. 553(b), (c)) regarding proposed rulemaking by 39 U.S.C. 410(a), the Postal Service invites public comments on the following proposed revisions to Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM), incorporated by reference in the Code of Federal Regulations.

We will publish an appropriate amendment to 39 CFR part 111 to reflect these changes.

Accordingly, the Postal Service proposes the following changes to Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM), incorporated by reference in the Code of Federal Regulations (see 39 CFR 111.1):

On March 7, 2025, the Rhode Island Department of Environmental Management (RIDEM) submitted a revision to its SIP to address regional haze for the second implementation period. RIDEM 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 Rhode Island regional haze SIP submission for the second implementation period meets the applicable statutory and regulatory requirements and thus proposes to approve Rhode Island's submission into its SIP.

On September 23, 2020, RIDEM submitted a SIP revision addressing, among other CAA requirements, the CAA section 110(a)(2)(D)(i)(II) visibility protection requirements for the 2015 ozone NAAQS. EPA is proposing to find that, with the approval of the state's regional haze plan, the SIP will contain adequate provisions to satisfy the requirements of CAA section 110(a)(2)(D)(i)(II) relating to visibility protection.

A detailed history and background of the regional haze program is provided in multiple prior EPA proposal actions. 1 For additional background on the 2017 RHR revisions, please refer to Section III. Overview of Visibility Protection Statutory Authority, Regulation, and Implementation of “Protection of Visibility: Amendments to Requirements for State Plans” of the 2017 RHR. 2 The following is an abbreviated history and background of the regional haze program and 2017 Regional Haze Rule as it applies to the current action.

In the 1977 CAA Amendments, Congress created a program for protecting visibility in the nation's mandatory Class I Federal areas, which include certain national parks and wilderness areas. 3 CAA 169A. The CAA establishes as a national goal the “prevention of any future, and the remedying of any existing, impairment of visibility in mandatory class I Federal areas which impairment results from manmade air pollution.” CAA 169A(a)(1).

Regional haze is visibility impairment that is produced by a multitude of anthropogenic sources and activities that are located across a broad geographic area and that emit pollutants that impair visibility. Visibility impairing pollutants include fine and coarse particulate matter (PM) ( e.g., sulfates, nitrates, organic carbon, elemental carbon, and soil dust) and their precursors ( e.g., sulfur dioxide (SO 2 ), nitrogen oxides (NO X ), and, in some cases, volatile organic compounds (VOC) and ammonia (NH 3 )). Fine particle precursors react in the atmosphere to form fine particulate matter (PM 2.5 ), which impairs visibility by scattering and absorbing light. Visibility impairment reduces the perception of clarity and color, as well as visible distance. 4

To address regional haze visibility impairment, the 1999 RHR established an iterative planning process that requires both states in which Class I areas are located and states “the emissions from which may reasonably be anticipated to cause or contribute to any impairment of visibility” in a Class I area to periodically submit SIP revisions to address such impairment. CAA 169A(b)(2); see also 40 CFR 51.308(b), (f) (establishing submission dates for iterative regional haze SIP revisions); 64 FR at 35768, July 1, 1999.

On January 10, 2017, the EPA promulgated revisions to the RHR, (82 FR 3078, January 10, 2017), that apply for the second and subsequent implementation periods. The reasonable progress requirements as revised in the 2017 rulemaking (referred to here as the 2017 RHR Revisions) are codified at 40 CFR 51.308(f).

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 one jurisdiction on the air quality in another. Five regional planning organizations (RPOs), 5 which include representation from state and tribal governments, the EPA, and federal land managers (FLMs), were developed in the lead-up to the first implementation period to address regional haze. RPOs evaluate technical information to better understand how emissions from State and Tribal land impact Class I areas across the country, pursue the development of regional strategies to reduce emissions of particulate matter and other pollutants leading to regional haze, and help states meet the consultation requirements of the RHR.

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).

Under the CAA and EPA's regulations, all 50 states, the District of Columbia, and the U.S. Virgin Islands are required to submit regional haze SIPs satisfying the applicable requirements for the second implementation period of the regional haze program by July 31, 2021. Each state's SIP must contain a long-term strategy for making reasonable progress toward meeting the national goal of remedying any existing and preventing any future anthropogenic visibility impairment in Class I areas. CAA 169A(b)(2)(B). To this end, 40 CFR 51.308(f) lays out the process by which states determine what constitutes their long-term strategies, with the order of the requirements in 40 CFR 51.308(f)(1) through (f)(3) generally mirroring the order of the steps in the reasonable progress analysis  6 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 (five-year average period of 2000-2004), current, and natural visibility conditions ( i.e., visibility conditions without anthropogenic visibility impairment) for that area, as well as the visibility improvement made to date and the “uniform rate of progress” (URP). The URP is the linear rate of progress needed to attain natural visibility conditions, assuming a starting point of baseline visibility conditions in 2004 and ending with natural conditions in 2064. This linear interpolation is used as a tracking metric to help states assess the amount of progress they are making towards the national visibility goal over time in each Class I area. See 40 CFR 51.308(f)(1). Each state having a Class I area and/or emissions that may affect visibility in a Class I area must then develop a long-term strategy that includes the enforceable emission limitations, compliance schedules, and other measures that are necessary to make reasonable progress in such areas. A reasonable progress determination is based on applying the four factors in CAA section 169A(g)(1) to sources of visibility-impairing pollutants that the state has selected to assess for controls for the second implementation period. 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”  7 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 Reasonable Progress Goals (RPGs) for each Class I area within its borders by modeling the visibility impacts of all reasonable progress controls at the end of the second implementation period, i.e., in 2028, as well as the impacts of other requirements of the CAA. The RPGs include reasonable progress controls not only for sources in the state in which the Class I area is located, but also for sources in other states that contribute to visibility impairment in that area. The RPGs are then compared to the baseline visibility conditions and the URP to ensure that progress is being made towards the statutory goal of preventing any future and remedying any existing anthropogenic visibility impairment in Class I areas. 40 CFR 51.308(f)(2)-(3). There are additional requirements in the rule, including FLM consultation, that apply to all visibility protection SIPs and SIP revisions. See e.g., 40 CFR 51.308(i).

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. 8 This is accomplished by considering the four factors—“the costs of compliance, the time necessary for compliance, and the energy and non-air quality environmental impacts of compliance, and the remaining useful life of any existing source subject to such requirements.” CAA 169A(g)(1). The EPA has explained that the four-factor analysis is an assessment of potential emission reduction measures ( i.e., control options) for sources; “use of the terms `compliance' and `subject to such requirements' in section 169A(g)(1) 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, 9 a state must consider a “meaningful set” of technically feasible control options for reducing emissions of visibility impairing pollutants. Id. at 3088.

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. 10 Ultimately, while states have discretion to reasonably weigh the factors and to determine what level of control is needed, 40 CFR 51.308(f)(2)(i) provides that a state “must include in its implementation plan a description of . . . how the four factors were taken into consideration in selecting the measure for inclusion in its long-term strategy.”

As explained above, 40 CFR 51.308(f)(2)(i) requires states to determine the emission reduction measures for sources that are necessary to make reasonable progress by considering the four factors. Pursuant to 40 CFR 51.308(f)(2), measures that are necessary to make reasonable progress towards the national visibility goal must be included in a state's long-term strategy and in its SIP. 11 If the outcome of a four-factor analysis is that an emissions reduction measure is necessary to make reasonable progress towards remedying existing or preventing future anthropogenic visibility impairment, that measure must be included in the SIP.

The characterization of information on each of the factors is also subject to the documentation requirement in 40 CFR 51.308(f)(2)(iii). The reasonable progress analysis is a technically complex exercise, and also a flexible one that provides states with bounded discretion to design and implement approaches appropriate to their circumstances. Given this flexibility, 40 CFR 51.308(f)(2)(iii) plays an important function in requiring a state to document the technical basis for its decision making so that the public and the EPA can comprehend and evaluate the information and analysis the state relied upon to determine what emission reduction measures must be in place to make reasonable progress. The technical documentation must include the modeling, monitoring, cost, engineering, and emissions information on which the state relied to determine the measures necessary to make reasonable progress.

Additionally, the RHR at 40 CFR 51.3108(f)(2)(iv) separately provides five “additional factors”  12 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.

Because the air pollution that causes regional haze crosses state boundaries, 40 CFR 51.308(f)(2)(ii) requires a state to consult with other states that also have emissions that are reasonably anticipated to contribute to visibility impairment in a given Class I area. If a state, pursuant to consultation, agrees that certain measures ( e.g., a certain emission limitation) are necessary to make reasonable progress at a Class I area, it must include those measures in its SIP. 40 CFR 51.308(f)(2)(ii)(A). Additionally, the RHR requires that states that contribute to visibility impairment at the same Class I area consider the emission reduction measures the other contributing states have identified as being necessary to make reasonable progress for their own sources. 40 CFR 51.308(f)(2)(ii)(B). If a state has been asked to consider or adopt certain emission reduction measures, but ultimately determines those measures are not necessary to make reasonable progress, that state must document in its SIP the actions taken to resolve the disagreement. 40 CFR 51.308(f)(2)(ii)(C). Under all circumstances, a state must document in its SIP submission all substantive consultations with other contributing states. 40 CFR 51.308(f)(2)(ii)(C).

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.

For the second implementation period, the RPGs are set for 2028. Reasonable progress goals are not enforceable targets. 40 CFR 51.308(f)(3)(iii). While states are not legally obligated to achieve the visibility conditions described in their RPGs, 40 CFR 51.308(f)(3)(i) requires that “[t]he long-term strategy and the reasonable progress goals must provide for an improvement in visibility for the most impaired days since the baseline period and ensure no degradation in visibility for the clearest days since the baseline period.”

RPGs may also serve as a metric for assessing the amount of progress a state is making towards the national visibility goal. To support this approach, 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.”

Section 51.308(f)(6) requires states to have certain strategies and elements in place for assessing and reporting on visibility. Individual requirements under this subsection apply either to states with Class I areas within their borders, states with no Class I areas but that are reasonably anticipated to cause or contribute to visibility impairment in any Class I area, or both. Compliance with the monitoring strategy requirement may be met through a state's participation in the Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring network, which is used to measure visibility impairment caused by air pollution at the 156 Class I areas covered by the visibility program. 40 CFR 51.308(f)(6), (f)(6)(i), (f)(6)(iv).

All states' SIPs must provide for procedures by which monitoring data and other information are used to determine the contribution of emissions from within the state to regional haze visibility impairment in affected Class I areas, as well as a statewide inventory documenting such emissions. 40 CFR 51.308(f)(6)(ii), (iii), (v). All states' SIPs must also provide for any other elements, including reporting, recordkeeping, and other measures, that are necessary for states to assess and report on visibility. 40 CFR 51.308(f)(6)(vi).

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 assess changes in visibility conditions and describe the status of implementation of all measures included in the state's long-term strategy, including of Best Available Retrofit Technology (BART) and reasonable progress emission reduction measures from the first implementation period, and the resulting emissions reductions. 40 CFR 51.308(g)(1) and (2).

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

RIDEM submitted its regional haze SIP for the first implementation period to the EPA on August 7, 2009. The EPA approved Rhode Island's first implementation period regional haze SIP submission on May 22, 2012 (77 FR 30214). EPA's approval included, but was not limited to, the portions of the plan that address the reasonable progress requirements, as well as Rhode Island's maintenance of nitrogen oxide emissions controls. 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), Rhode Island was also responsible for submitting a five-year progress report as a SIP revision for the first implementation period, which it did on January 7, 2015. The EPA approved the progress report into the Rhode Island SIP on July 20, 2016 (81 FR 47036).

In accordance with CAA section 169A and the RHR at 40 CFR 51.308(f), on March 7, 2025, Rhode Island submitted a revision to the Rhode Island SIP to address its regional haze obligations for the second implementation period, which runs through 2028. Rhode Island made a draft Regional Haze SIP submission available for public comment on January 24, 2025. Rhode Island did not receive any public comments during the public comment period, which concluded on February 28, 2025.

The following sections describe Rhode Island's SIP submission, including analyses conducted by MANEVU and Rhode Island's determinations based on those analyses, Rhode Island'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 notice also contains EPA's evaluation of Rhode Island's submission against the requirements of the CAA and RHR for the second implementation period of the regional haze program.

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. Rhode Island has no mandatory Class I Federal area within its borders.

For the second implementation period, MANEVU performed technical analyses  13 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.”  14 Similar to metrics used in the first implementation period, 15 MANEVU used a greater than 2 percent of sulfate plus nitrate emissions contribution criterion 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 SO 2 emissions and resultant particulate sulfate contributions to visibility impairment, some also incorporated NO X emissions to estimate particulate nitrate contributions.

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 SO 2 and NO X . The list of EGUs was based on an enhanced “Q/d” analysis  16 that considered recent SO 2 emissions in the eastern United States and an analysis that adjusted previous 2002 MANEVU CALPUFF modeling by applying a ratio of 2011 to 2002 SO 2 emissions. This list of sources was then enhanced by including the top five SO 2 and NO X 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. 17 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. CALPUFF modeling did not include any individual EGU or industrial/institutional point sources in Rhode Island because the state's SO 2 and NO X emissions were much lower than the other regional sources considered in the CALPUFF modeling analysis. 18

The second MANEVU contribution analysis used a meteorologically weighted Q/d calculation to assess states' contributions to visibility impairment at MANEVU Class I areas. 19 This analysis focused predominantly on SO 2 emissions and used cumulative SO 2 emissions from a source and a state for the variable “Q,” and the distance of the source or state to the IMPROVE monitor receptor at a Class I area as “d.” The result is then multiplied by a constant (C i ), which is determined based on the prevailing wind patterns. MANEVU selected a meteorologically weighted Q/d analysis as an inexpensive initial screening tool that could easily be repeated to determine which states, sectors, or sources have a larger relative impact and warrant further analysis. Although MANEVU did not originally estimate nitrate impacts, the MANEVU Q/d analysis was subsequently extended to account for nitrate contributions from NO X emissions and to approximate the nitrate impacts from area and mobile sources. MANEVU therefore developed a ratio of nitrate-to-sulfate impacts based on the previously described CALPUFF modeling and applied those to the sulfate Q/d results in order to derive nitrate contribution estimates. Several states, such as Rhode Island, did not have CALPUFF nitrate-to-sulfate ratio results because there was no point sources modeled with CALPUFF in the state.

In order to develop a final set of contribution estimates, MANEVU weighted the results from both the Q/d and CALPUFF analyses. The MANEVU mass-weighted sulfate and nitrate contribution results were reported for the MANEVU Class I areas. (The Q/d summary report included results for several non-MANEVU areas as well). If a state's contribution to sulfate and nitrate concentrations at a particular Class I area was 2 percent or greater, MANEVU regarded that state as contributing to visibility impairment in that area. According to MANEVU's analyses, Rhode Island's highest percent mass-weighted sulfate and nitrate contribution was estimated to be 0.5% at Acadia National Park in Maine, with contributions ranging from 0.1% to 0.3% at the other Class I areas in the MANEVU region. 20

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. 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. 21 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”  22 of states and sources both within and upwind of MANEVU. 23 The EPA finds the nature of the analyses generally appropriate to support decisions on states with which to consult.

With regard to the analysis and determinations regarding Rhode Island'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 Rhode Island emissions on nearby Class I areas. The MANEVU contribution screening results estimate Rhode Island's highest percent mass- weighted sulfate and nitrate contribution to be 0.5% at Acadia National Park, with the Brigantine Wilderness Area being the next closest Class I area impacted by Rhode Island emissions at 0.3%. 24 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 SO 2 and NO X 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 Rhode Island's emissions at nearby out-of-state Class I areas is smaller than that from numerous other MANEVU states. 25 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. Additionally, we note that the 2 percent or greater sulfate-plus-nitrate threshold used to determine whether Rhode Island 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 Rhode Island 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.

In any event, pursuant to the regulatory requirements, Rhode Island 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. 26 Rhode Island'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. Rhode Island worked with MANEVU to determine potential reasonable measures that could be implemented by 2028, considering the cost of compliance, the time necessary for compliance, the energy and non-air quality environmental impacts, and the remaining useful life of any potentially affected sources. 27 As discussed in further detail below, the EPA is proposing to find that Rhode Island 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 Rhode Island 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.

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).

Rhode Island 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. 28 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 Wilderness Area (Maine) (used to represent Roosevelt Campobello International Park), Roosevelt Campobello International Park (New Brunswick, Canada), and Brigantine Wilderness Area (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).

Each state having a Class I area within its borders or emissions that may affect visibility in a Class I area must develop a long-term strategy for making reasonable progress towards the national visibility goal. CAA § 169A(b)(2)(B). After considering the four statutory factors, all measures that are determined to be necessary to make reasonable progress must be in the long-term strategy. In developing its long-term strategy, a state must also consider the five additional factors in 40 CFR 51.308(f)(2)(iv). As part of its reasonable progress determinations, the state must describe the criteria used to determine which sources or group of sources were evaluated ( i.e., subjected to four-factor 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 Rhode Island's SIP submission addressed the requirements of 40 CFR 51.308(f)(2)(i); specifically, it describes MANEVU's development of the six Asks and how Rhode Island addressed each. The regulations Rhode Island identifies as a result of its responses to the six Asks comprise Rhode Island'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 Rhode Island. In Section IV.E.b. of the NPRM, EPA evaluates Rhode Island's compliance with the requirements of 40 CFR 51.308(f)(2)(i).

States may rely on technical information developed by the RPOs of which they are members to select sources for four-factor analysis and to conduct that analysis, as well as to satisfy the documentation requirements under 40 CFR 51.308(f). Where an RPO has performed source selection and/or four-factor analyses (or considered the five additional factors in 40 CFR 51.308(f)(2)(iv)) for its member states, those states may rely on the RPO's analyses for the purpose of satisfying the requirements of 40 CFR 51.308(f)(2)(i) so long as the states have a reasonable basis to do so and all state participants in the RPO process have approved the technical analyses. 40 CFR 51.308(f)(2)(iii). States may also satisfy the requirement of 40 CFR 51.308(f)(2)(ii) to engage in interstate consultation with other states that have emissions that are reasonably anticipated to contribute to visibility impairment in a given Class I area under the auspices of intra- and inter-RPO engagement.

Rhode Island 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 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. 29 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.”  30 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.”  31

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, Rhode Island'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)  32 at MANEVU and nearby Class I areas. MANEVU found that while SO 2 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, NO X emissions have begun to play a more significant role in visibility impacts in recent years as SO 2 emissions have decreased. The technical analyses used by Rhode Island are included in its submission and are as follows:  33

• 2016 Updates to the Assessment of Reasonable Progress for Regional Haze in MANEVU Class I Areas (Appendix 6);

• Impact of Wintertime SCR/SNCR Optimization on Visibility Impairing Nitrate Precursor Emissions. November 2017 (Appendix 17);

• High Electric Demand Days and Visibility Impairment in MANEVU. December 2017 (Appendix 18);

• Benefits of Combined Heat and Power Systems for Reducing Pollutant Emissions in MANEVU States. March 2016 (Appendix 7);

• 2016 MANEVU Source Contribution Modeling Report—CALPUFF Modeling of Large Electrical Generating Units and Industrial Sources. April 4, 2017 (Appendix 8);

• Contribution Assessment Preliminary Inventory Analysis. October 10, 2016 (Appendix 11);

• Four-Factor Data Collection Memo. March 2017 (Appendix 14);

• Status of the Top 167 Stacks from the 2008 MANEVU Ask. July 2016 (Appendix 10);

• Mid-Atlantic/Northeast U.S. Visibility Data, 2004-2019 (2nd RH SIP Metrics) (Appendix 22);

• Selection of States for MANEVU Regional Haze Consultation 2018 (Appendix 16);

• Ozone Transport Commission/MANEVU 2011 Based Modeling Platform Support Document October (2018 Update) (Appendix 21).

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 SO 2 and/or NO X ] that were reasonably] 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. 34 MANEVU also collected data on individual sources within the EGU, ICI boiler, and cement kiln sectors. 35 Information for the six sectors included explanations of technically feasible control options for SO 2 or NO X, 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. 36 Source-specific data included SO 2 emissions  37 and existing controls  38 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. 39 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.

MANEVU Ask 1 is “ensuring the most effective use of control technologies on a year-round basis” at EGUs with a nameplate capacity larger than or equal to 25 megawatts (MW) with already installed NO X and/or SO 2 controls in order to consistently minimize emissions of haze precursors or obtain equivalent alternative emission reductions. MANEVU observed that EGUs often only run NO X emissions controls to comply with ozone season trading programs and consequently, NO X 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 NO X emissions from EGUs; and (2) that running existing controls year-round could substantially reduce the NO X emissions in many of the states upwind of Class I areas in MANEVU that lead to visibility impairment during the winter from nitrates. 40 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.

Rhode Island identified 5 EGU units that meet the criteria of 25 MW or larger with installed controls. 41 All of the identified units are natural gas-fired and use SCR to control nitrogen oxide emissions. Rhode Island explained that all of the identified units are Title V sources that were subject to prevention of significant deterioration (PSD) permitting requirements. The permits require these facilities to operate their controls year-round except during start up. The requirements and enforceability are reviewed at least once every five years, the sources are inspected every two years, and the permits are federally enforceable. Since these controls are already in effect and are required to operate year-round, Rhode Island concluded that it has therefore met the requirements of Ask 1. Rhode Island also noted that a sixth natural gas-fired EGU—Pawtucket Power—permanently shut down in 2021 and that its title V permit was revoked. 42 As of 2025, the facility is completely decommissioned and demolished. 43

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. 44 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 Rhode Island with a potential impact of at least 3.0 Mm −1 . 45 In its submittal, Rhode Island presents further information about the State's largest NO X and SO 2 sources and the controls each employs. Based on 2017 emissions data, only four sources in the State had SO 2 emissions greater than 10 tpy, with the smallest source at about 15 tpy and the largest just under 69 tpy. Only eight sources had NO X emissions greater than 50 tpy, with the lowest at about 52 tpy and the largest at 244 tpy. 46 Based on the lack of sources at or above the 3.0 Mm −1 threshold, further illustrated by the generally small size of its largest sources, Rhode Island concluded that it satisfied Ask 2.

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.” Effective June 24, 2014, RIDEM Office of Air Resources (OAR) finalized amendments to 250-RICR-120-05-8: Sulfur Content of Fuels. The first phase of limitations lowered the allowable concentration of sulfur in distillate oil and biodiesel to 0.05% (500 ppm) by weight, effective July 1, 2014. In 2018, the beginning of the second implementation period, the second phase of limitations further lowered the limit to 0.0015% (15 ppm) by weight. In addition, the second phase also lowered the sulfur limit for residual oil and alternative fuel to 0.5% (5000 ppm) by weight. EPA approved 250-RICR-120-05-8: Sulfur Content of Fuels into Rhode Island's SIP on August 13, 2018 [83 FR 39888]. Since Rhode Island has fully implemented an ultra-low sulfur fuel oil standard, the State therefore concluded that it met Ask 3.

MANEVU Ask 4 requests states to update permits to “lock in” lower emissions rates for NO X , SO 2 , 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. The threshold of 250 MMBTU/hour was based on prior BART analysis. There aren't any coal burning units or non-EGU units having a heat input capacity larger than 250 MMBtu/hr in Rhode Island. While there are three EGUs in Rhode Island above this threshold that continue to burn both natural gas and oil, their oil use is generally limited to periods when natural gas is not available. Rhode Island explains that these sources are subject to Title V permitting requirements under 250-RICR-120-05-29, which specify allowable operating scenarios, and fuels fired. Rhode Island further explains that these sources are reviewed every five years, and if a change in fuel type may increase emissions, or is otherwise not allowed by the permit, it triggers requirements for a new or modified preconstruction permit. Rhode Island concluded that it therefore meets the requirements of Ask 4.

Ask 5 requests that MANEVU states “control NO X emissions for peaking combustion turbines that have the potential to operate on high electric demand days” by either: (1) Meeting NO X 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. 47 The Ask requests states to strive for NO X emission standards of no greater than 25 ppm for natural gas and 42 ppm for fuel oil, or at a minimum, NO X emissions standards of no greater than 42 ppm for natural gas and 96 ppm at for fuel oil. MANEVU defined a “peaking combustion turbine” for this Ask to be “a turbine capable of generating 15 megawatts or more, that commenced operation prior to May 1, 2007, is used to generate electricity all or part of which is delivered to the electric power distribution grid for commercial sale and that operated less than or equal to an average of 1752 hours (or 20%) per year during 2014 to 2016.” After reviewing permit files, air pollution inventory files, RI Office of Energy Resources (OER) data, and Energy Information Administration (EIA) data, RIDEM OAR did not identify any turbines in the State that met the criteria of the Ask. 48 Therefore, Rhode Island concluded that it satisfies the requirements of Ask 5.

The last Ask for states within MANEVU (Ask 6) requests states to report in their regional haze SIPs about programs that decrease energy demand and increase the use of combined heat and power (CHP) and other distributed generation technologies such as fuel cells, wind and solar. Rhode Island reports that its OER continuously develops, administers, and monitors a variety of programs focused on energy efficiency, renewable energy, alternative fuels and energy assurance. Based on 2021 data, Rhode Island's energy efficiency programming achieved savings of 1.8% of electricity consumption and 0.74% of natural gas consumption, and in 2022, Rhode Island was ranked 7th most energy-efficient state in the country. 49 Rhode Island utilizes the “Lead by Example” initiative, which coordinates state-level efforts to reduce energy consumption and greenhouse gas (GHG) emissions. For example, the Public School Energy Equity Program has led to the energy improvement of 28 schools in Rhode Island, with a lifetime estimated energy savings of 43,238,884 kWh. Under Rhode Island General Law Chapter 46-12.24.2, The Efficient Buildings Fund has provided approximately 70 million dollars for energy efficiency and renewable energy projects as of 2022. Rhode Island has also implemented programs which contribute to reductions in transportation related emissions. For example, Electrify RI increases the availability and accessibility of electric vehicle charging stations. Additionally, the DRIVE EV program offers rebate incentives for the purchase of electric vehicles and was recently expanded to include electric bicycles via the Erika Niedowski Memorial Electric Bicycle Rebate Program. Rhode Island is also part of the Regional Greenhouse Gas Initiative (RGGI). MANEVU found that the RGGI cooperative results in substantial reductions in emissions of SO 2 and NO X from the member states.

Continued growth is expected in both distributed generation and combined heat and power plants in Rhode Island. Currently, there are seven distributed generators in Rhode Island and several emergency generators which have submitted permit applications to convert to distributed generators. The units are subject to federal emissions standards as required by permit and capped at 500 hours per year. There are also four combined heat and power plants generating approximately 40 MW of electricity. Due to the initiatives described above, 50 Rhode Island concluded that it satisfies Ask 6.

In summary, Rhode Island identified the following SIP-approved programs as necessary for reasonable progress and therefore included in the State's long term strategy: 250-RICR-120-05-8, fuel sulfur content limitations; 250-RICR-120-05-27, control of nitrogen oxides emissions from fuel-burning equipment at major stationary sources of nitrogen oxides; the 2021 retirement of Pawtucket Power and the revocation of its title V Permit. 51

The EPA is proposing to find that Rhode Island has satisfied the requirements of 40 CFR 51.308(f)(2)(i) related to evaluating sources and determining the emission reduction measures that are necessary to make reasonable progress by considering the four statutory factors. We are proposing to find that Rhode Island has satisfied the requirement to consider the four statutory factors through its analysis and actions to address Ask 3. Additionally, in line with recent proposals from the EPA, 52 where visibility conditions for a Class I area impacted by a state are below the URP and the state has considered the four statutory factors, the state will have presumptively demonstrated reasonable progress for the second planning period for that area. While Rhode Island's regional haze plan is not relying on this policy, the current visibility conditions of the Class I areas in or adjacent to the MANEVU region are below their respective URP glidepaths, providing further support for approval.

As explained above, Rhode Island 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 SO 2 and NO X 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 SO 2 include coal-fired EGUs, industrial boilers, oil-fired EGUs, and oil-fired area sources including residential, commercial, and industrial sources. The largest sources of NO X include onroad vehicles, nonroad vehicles, and EGUs. 53 The RPO's documentation explains that “[EGUs] emitting SO 2 and NO X and industrial point sources emitting SO 2 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.”  54 EPA proposes to find that Rhode Island reasonably evaluated the two pollutants—SO 2 and NO X —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.

Section 51.308(f)(2)(i) requires states to evaluate sources or groups of sources and determine the emission reduction measures that are necessary to make reasonable progress by considering the four statutory factors. 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 control strategies, and Rhode Island identified numerous existing controls that are in the SIP and are included in the long-term strategy. For example, Rhode Island's response to Ask 2 examines the state's largest emitters and their current emissions limitations and control equipment. While MANEVU formulated the Asks to be “reasonable emission reduction strategies” to control emissions of visibility impairing pollutants, 55 Rhode Island's response to 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 analyses conducted to support emission reduction measures, including Ask 3, satisfy the requirement of 40 CFR 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 Rhode Island's SIP. 40 CFR 51.308(f)(2).

Rhode Island asserted that it satisfies Ask 1 because the state permits for the five EGUs covered by this Ask include year-round emission limits and require that controls (SCR in each case) be run at all times the units are in operation and emitting air pollutants. As each of these units are at Title V sources, the requirements are federally enforceable, and Rhode Island renews the permits every five years. EPA thus agrees that Rhode Island 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 the emissions reduction measures necessary to make 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.”  56

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. 57 In this case, applying the 3.0 Mm −1 threshold did not identify any sources in Rhode Island (and only 22 across the entire MANEVU region). We 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.

As part of the requirement to evaluate and determine the emissions reduction measures that are necessary to make reasonable progress, Rhode Island reviewed existing controls for the state's top emitting sources. Using 2017 emissions data, Rhode Island evaluated its EGU and non-EGU SO 2 sources with emissions greater than 10 tpy and NO X sources with emissions greater than 50 tpy. 58 Rhode Island Hospital, the state's top SO 2 source (~69 tpy) and also the state's seventh highest NO X -emitting source (~57 tpy), operates five boilers which are equipped with various control measures. 59 The next top three SO 2 sources collectively accounted for less than 100 tons in 2017. 60 Rhode Island's top NO X emitter, Manchester Street Station, emitted 243.66 tons of NO X in 2017. 61 The facility operates three combustion turbines, which are equipped with SCR. Rhode Island's next highest NO X emitter, Ocean State Power, accounted for 156.55 tons in 2017. 62 Ocean State Power operates four combustion turbines, which are also equipped with SCR. 63 Rhode Island's next top six NO X emitters collectively accounted for 376 tons in 2017. 64 Each facility identified in Rhode Island's review is a title V source with an active operating permit that must be updated and renewed every five years with public involvement. 65 Each unit is subject to all applicable Federal and State regulations as identified in each source's enforceable permit. EPA is basing the proposed finding on the state's examination of its largest operating sources at the time of SIP submission, and on the emissions from and controls that apply to those sources, as well as on Rhode Island's existing SIP-approved NO X and SO 2 rules that effectively control emissions from the largest contributing stationary-source sectors.

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;  66 specifically, 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 onroad and nonroad-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 onroad and nonroad 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.”  67 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. 68

The EPA agrees that Rhode Island 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, RIDEM OAR finalized amendments to 250-RICR-120-05-8: Sulfur Content of Fuels, effective June 24, 2014. The first phase of limitations lowered the allowable concentration of sulfur in distillate oil and biodiesel to 0.05% (500 ppm) by weight, effective July 1, 2014. Beginning July 1, 2018, the limit was further lowered to 0.0015% (15 ppm) by weight. In addition, the second phase also lowered the sulfur limit for residual oil and alternative fuel to 0.5% (5000 ppm) by weight. EPA approved 250-RICR-120-05-8: Sulfur Content of Fuels into Rhode Island's SIP on August 13, 2018. 83 FR 39888. Since Rhode Island has fully implemented an ultra-low sulfur fuel oil standard 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 Rhode Island satisfied Ask 3.

Rhode Island concluded that it satisfies the requirements of Ask 4, which requests that MANEVU states pursue updating permits, enforceable agreements, and/or rules to lock-in lower emission rates for SO 2 , NO X and PM at EGUs and other sources larger than 250 MMBtu per hour that have switched operations to lower emitting fuels. Rhode Island does not have any large, coal-burning EGUs or non-EGUs meeting the threshold of this Ask. While Rhode Island identified three EGUs that have a heat input capacity greater than the 250 MMBtu/hr threshold and that can burn both natural gas and oil, as noted above, their oil use is generally limited by permit to periods when natural gas is not available. In New England, this is generally limited to cold weather periods when natural gas is diverted from EGUs for use in residential heating. 69 Rhode Island also explained that these three EGUs are already subject to title V permitting requirements under 250-RICR-120-05-29, “Operating Permits,” which 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 preconstruction permit. EPA acknowledges Rhode Island's conclusion that it meets the requirements of Ask 4.

Ask 5 addresses NO X emissions from peaking combustion turbines that have the potential to operate on high electric demand days. RIDEM reviewed permit files, air pollution inventory files, RI OER data, and U.S. EIA data, and did not identify any turbines that meet the criteria of this Ask. That is, Rhode Island does not have any units rated at 15MW or higher that were operational prior to 2007 that sold electricity to the grid and operated less than an average of 1752 hours per year during 2014-2016. EPA agrees that Rhode Island reasonably demonstrated that it meets Ask 5.

Finally, regarding Ask 6, Rhode Island pointed to various policy efforts to increase energy efficiency and reduce reliance on fossil fuels for energy. Rhode Island is nationally recognized as a leader in energy efficiency. As discussed in Section IV.E.a., Rhode Island's OER spearheads a multitude of major programs focused on energy efficiency, renewable energy, alternative fuels and energy assurance. EPA agrees that Rhode Island has satisfied the request of Ask 6 to consider and report in its SIP measures or programs related to energy efficiency, cogeneration, and other clean distributed generation technologies.

In sum, Rhode Island identified several mechanisms for controlling pollutants that impair visibility—including its regulation limiting sulfur content in fuels (which is in Rhode Island's SIP), as well as the continued implementation of NO X RACT for point sources. EPA proposes to find that Rhode Island has reasonably concluded that these measures are necessary to make reasonable progress for the second planning period.

In addition to these SIP-approved measures, Rhode Island also identified other federally enforceable and permanent controls, including its mobile source control measures, as key emission reduction strategies. Onroad mobile emissions reductions are due in part to Rhode Island's adoption of more stringent motor vehicle emission standard regulations. 70 These SIP-approved standards ensure that vehicles sold in the state meet increasingly stringent emissions requirements through time. Other efforts to reduce air pollution from onroad mobile sources include adoption of inspection and maintenance of vehicle emissions control systems.

EPA is therefore proposing to find the state's approach meets the statutory and regulatory requirements for several reasons. Specifically, EPA is proposing to find—based on Rhode Island's participation in the MANEVU planning process, how it has addressed the Asks, and the EPA's assessment of Rhode Island's emissions and point sources—that Rhode Island has complied with the requirements of section 51.308(f)(2)(i). Rhode Island'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.

In determining the emissions reduction measures necessary to make reasonable progress, Rhode Island reasonably evaluated and explained its decision to focus on SO 2 and NO X to address visibility impairment within the MANEVU region. Rhode Island adequately supported that decision through reasonable reliance on the MANEVU technical analyses cited in its submission. EPA notes that MANEVU concluded that sulfates from SO 2 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 SO 2 emissions. Rhode Island's SIP-approved sulfur in fuel rule, 250-RICR-120-05-8: Sulfur Content of Fuels, sets stringent limits for sulfur content and SO 2 emissions for fuels. Rhode Island's rule controls SO 2 emissions from area and point sources by limiting the sulfur content of distillate oil and biodiesel to 0.0015% and the sulfur content of residual oils and alternative fuels to 0.5%. EPA previously approved these requirements into Rhode Island's SIP, and they went into effect in July 2018. Rhode Island's submittal also includes evaluations of the state's largest SO 2 and NO X sources which demonstrate that these facilities have relatively small emissions of NO X and SO 2 and are already subject to stringent emission control measures. For instance, while the state contains no ozone nonattainment areas, Rhode Island is nonetheless required to apply NO X RACT to certain sources, owing to its location within the Ozone Transport Region. EPA approved Rhode Island's latest NO X RACT rule in 2020, 71 which has been employed on Rhode Island's highest NO X emitting point source, Manchester Street Station, among others. As discussed previously, continued implementation of federal mobile source programs will provide further reductions in NO X emissions from Rhode Island. Moreover, the FLMs responsible for the Class I areas most impacted by Rhode Island emissions sources (Acadia National Park, Lye Brook, Brigantine Wilderness, etc.)  72 did not identify any sources in Rhode Island for four-factor analysis or request any revisions or other analyses. 73 In particular, the US Forest Service stated that it had “conducted a substantive review” of Rhode Island's plan, was “satisfied” with it, and “offer[ed] no suggestions for change.”  74 Similarly, the National Park Service commended Rhode Island on its draft submission and stated it had no further conclusions or recommendations. 75 In short, Rhode Island's SO 2 and NO X emissions are already low, are controlled by EPA-approved limits in the SIP (as a result of Regional Haze and other CAA requirements), and have overall small contributions to visibility impairment in Class I areas. The projected 2028 visibility conditions for Class I areas influenced by emissions from Rhode Island sources are all below the URP, and EPA proposes to find that Rhode Island's SIP submittal satisfies the requirements that states determine the emission reduction measures that are necessary to make reasonable progress by considering the four factors and that their long-term strategies include the enforceable emission limitations, compliance schedules, and other measures necessary to make reasonable progress.

The consultation requirements of 40 CFR 51.308(f)(2)(ii) provide that states must consult with other states that are reasonably anticipated to contribute to visibility impairment in a Class I area to develop coordinated emission management strategies containing the emission reductions measures that are necessary to make reasonable progress. Section 51.308(f)(2)(ii)(A) and (B) require states to consider the emission reduction measures identified by other states as necessary for reasonable progress and to include agreed upon measures in their SIPs. Section 51.308(f)(2)(ii)(C) speaks to what happens if states cannot agree on what measures are necessary to make reasonable progress.

Rhode Island 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 Rhode Island 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. Rhode Island addressed impacts to the MANEVU Class I areas by providing information on the enforceable measures it has in place that satisfy each Ask. 76 Rhode Island included in its Regional Haze SIP submittal all measures agreed to during state-to-state consultations and emission reduction measures identified by other states. While Rhode Island did not receive any requests from non-MANEVU states during its public comment period to consider additional measures to address visibility impairment in Class I areas outside MANEVU, MANEVU documented issues some non-MANEVU states raised about MANEVU's analyses 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. 77 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 Rhode Island 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.

In sum, Rhode Island 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 40 CFR 51.308(f)(2)(ii)(A) and (B). Rhode Island satisfied 40 CFR 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, including the MANEVU responses to other states' concerns and various technical analyses in the SIP submission, we propose to determine that Rhode Island has satisfied the consultation requirements of section 51.308(f)(2)(ii).

The documentation requirement of 40 CFR 51.308(f)(2)(iii) provides that states may meet their obligations to document the technical bases on which they are relying to determine the emission reductions measures that are necessary to make reasonable progress through an RPO, as long as the process has been “approved by all State participants.” As explained above, Rhode Island 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 Rhode Island 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. Rhode Island also provided 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 Rhode Island satisfies this requirement of 40 CFR 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. Rhode Island drafted the plan using the 2017 NEI emission data for NO X , SO 2 , PM, VOCs and NH 3 . Additionally, Rhode Island included Air Markets Program Data (AMPD) emissions for NO X and SO 2 until 2019. The 2020 NEI indicates relatively minor increases in NO X emissions from certain EGUs. Rhode Island, as indicated throughout this notice, evaluated these facilities and in-place NO X control measures. For example, while Ocean State Power experienced a small increase in NO X emissions totaling around 10 tpy, this facility is already equipped with SCR. Despite minor increases from certain sources, NO X EGU emissions in Rhode Island experienced a minor decline overall in 2020. A portion of this reduction came from Rhode Island's largest NO X emitter, Manchester Street Station, with NO X emissions falling nearly 40 tpy from 2017 to 2020. 78 The 2020 NEI also shows a minor net increase in EGU emissions of SO 2 . Rhode Island, however, as previously discussed in the evaluation of Ask 3, continues to employ the use of low sulfur fuel oil, which the state adopted based off consideration of the four factors. It is likely, given the State's overall relatively small emissions and the level of control through existing programs, that consideration of the 2020 NEI would not have affected Rhode Island's source selection and analysis. Based on Rhode Island's consideration and analysis of the emission data in its SIP submittal, the EPA proposes to find that Rhode Island has satisfied the emissions information requirement in 40 CFR51.308(f)(2)(iii).

We also propose to find that Rhode Island reasonably considered the five additional factors in 40 CFR 51.308(f)(2)(iv) in developing its long-term strategy. Pursuant to 40 CFR 51.308(f)(2)(iv)(A), Rhode Island 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. RIDEM OAR considered these reductions as part of the MANE-VU process that generated emission inventories and projections that reflect ongoing programs and were incorporated into the modeling for the RPGs (see appendix 5 of the state's submittal for controls included in the inventories and Section 2 of the state's submittal for the RPGs). These also were considered in the emissions rates used in the CALPUFF and Q/d screening models. Additionally, Rhode Island notes the state's commitment to reduce mobile source emissions through numerous programs and regulations that will have a positive visibility impact both in and out of Rhode Island.

Rhode Island's consideration of measures to mitigate the impacts of construction activities as required by 40 CFR 51.308(f)(2)(iv)(B) includes, in section 6.5 of its SIP submission, discussion of Rhode Island regulation 250-RICR-120-05-5, “Fugitive Dust,” which regulates dust from construction and demolition activities. The regulation provides that “No person shall cause or permit any materials, including but not limited to sand, gravel, soil, aggregate and any other organic or inorganic solid matter capable of releasing dust, to be handled, transported, mined, quarried, stored or otherwise utilized in any way so as to cause airborne particulate matter to travel beyond the property line of the emission source without taking adequate precautions to prevent particulate matter from becoming airborne.” Rhode Island also considered this regulation's role in mitigating impacts from construction activities when it developed its long-term strategy for the first planning period. Rhode Island further notes that MANEVU analysis for the second implementation period found that crustal material does not play a major role in visibility impairment at Class I areas. 79 RIDEM OAR concluded that its regulations are sufficient to mitigate the impacts of construction activities.

Pursuant to 40 CFR 51.308(f)(2)(iv)(C), source retirements and replacement schedules are addressed in section 6.6 of Rhode Island's submittal. Rhode Island considered source retirements and replacements in developing the 2028 emission inventories described in Section 4 of the submittal, as described in the Gamma Inventory technical support documentation in appendix 19, and in RIDEM OAR's implementation of the 2017 MANE-VU Statement. The sources that were subsequently retired after the 2011 base year and therefore not included in the 2028 inventory are listed in Table 6-7 of the Rhode Island submittal.

In considering smoke management as required in 40 CFR 51.308(f)(2)(iv)(D), Rhode Island explained that Smoke Management Programs (SMP) are only required when smoke impacts from fires managed for resource benefits contribute significantly to regional haze. 80 The 2017 NEI indicates that prescribed forest and agricultural fires emissions in Rhode Island are very minor; the inventory estimates that those emissions from those source categories totaled 34 tons of PM 10 , 29 tons of PM 2.5 and 4 tons of SO 2 in 2017, which constitutes only a small portion of the total Rhode Island PM 2.5 , PM 10 , and SO 2 inventories (0.84%, 0.47%, 0.51%, respectively). Therefore, RIDEM OAR concludes that no substantial change has occurred that would alter the conclusions of the previous SIP regarding the sources of visibility impairment, and therefore no change is needed to make reasonable progress. EPA agrees that Rhode Island adequately considered smoke management practices as part of its submittal as required by 40 CFR 51.308(f)(2)(iv)(D).

Rhode Island considered the anticipated net effect of projected changes in point, area, and mobile source emissions over the period addressed by the LTS ( i.e., 2018-2028) as required by 40 CFR 51.308(f)(2)(iv)(E). Rhode Island considered the MANEVU-developed inventory projections and modeling for visibility impact for 2028 that incorporated the “Asks” for MANEVU states as well as the Asks developed for upwind states and EPA/FLMs. These projections and modeling incorporated the RIDEM OAR LTS from the first implementation period with no additional regulatory action for the second implementation period. The results of that modeling are shown as RPGs in Section 2 of the submittal and are also detailed in the presentation of RPGs in the MANE-VU visibility report. 81 The 2028 inventory projections demonstrate a substantial reduction in emissions and the modeling demonstrates a substantial improvement in visibility impairment through 2028. 82

Because Rhode Island has reasonably considered each of the five additional factors, the EPA proposes to find that Rhode Island has satisfied the requirements of 40 CFR 51.308(f)(2)(iv).

Section 51.308(f)(3) contains the requirements pertaining to RPGs for each Class I area. Because Rhode Island does not host a Class I area, it is not subject to either 40 CFR 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 demonstrate that there are no additional emission reduction measures that may reasonably be anticipated to contribute to visibility impairment in the Class I area that would be reasonable to include in the long-term strategy.

None of the Class I areas in or adjacent to the MANEVU region have RPGs above their respective URP glidepath. Table 2-1 of Rhode Island's SIP submittal summarizes baseline, current, and reasonable progress goal haze index levels for class I areas in or adjacent to the MANEVU region. The table displays baseline ( i.e., visibility conditions during 2000-2004), natural, and current (2015-2019) visibility conditions for the most impaired and clearest days at each area. Additionally, Table 2-1 of the submittal shows the 2028 modeled visibility values with projected controls for the most impaired days and how those values compare to the URP glidepaths for 2028. The 2028 RPGs for each Class I area are well below their respective URP glidepath. Therefore, 40 CFR 51.308(f)(3)(ii)(B) is not applicable to Rhode Island.

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 Rhode Island does not contain any Class I areas, it is not required to submit the monitoring strategy referenced in 51.308(f)(6), nor are the requirements in 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 Rhode Island) 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. Visibility data analysis procedures are described in the MANEVU visibility data report. Other procedures and data used for determining Rhode Island's contribution to visibility impairment are described in section 4 of the Rhode Island SIP and the MANEVU documents referenced. 83

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. Rhode Island 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 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 4 of Rhode Island's submission includes tables of NEI data. The source categories of the emissions inventories included are: (1) Point sources, (2) nonpoint sources, (3) nonroad mobile sources, and (4) onroad mobile sources. The point source category is further divided into AMPD point sources and non-AMPD point sources. Rhode Island 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: SO 2 , NO X , PM 10 , PM 2.5 , VOCs, and NH 3 . Rhode Island also provided a summary of SO 2 and NO X emissions for AMPD sources for the years 2002, 2008, 2011, 2014, and 2016-2019. Consideration of the 2020 NEI data shows small variability in emissions. However, the more recent emission data would likely not have affected Rhode Island's source selection or analysis of the already well- controlled facilities.

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. 84 Rhode Island 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. 85 The EPA proposes to find that Rhode Island 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 Rhode Island to assess and report on visibility pursuant to 40 CFR 51.308(f)(6)(vi).

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, 40 CFR 51.308(g)(5), which also applies to all states, requires an assessment of any significant changes in anthropogenic emissions within or outside the state that have occurred since the period addressed by the first implementation period progress report, including whether such changes were anticipated and whether they have limited or impeded expected progress towards reducing emissions and improving visibility.

Rhode Island's submission describes the status of measures of the long-term strategy from the first implementation period. 86 As a member of MANEVU, Rhode Island 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.

During the first planning period for regional haze, programs that were put in place focused on reducing SO 2 emissions. Effective June 24, 2014, RIDEM OAR finalized amendments to 250-RICR-120-05-8: Sulfur Content of Fuels to lower the sulfur content of fuel oil. This rule was fully implemented by July 1, 2018, and Rhode Island continues to enforce the requirements of this regulation. The other MANEVU states implemented similar rules, and the reductions achieved from these and other measures reduced sulfates formed from SO 2 emissions and led to vast improvements in visibility at the MANEVU Federal Class I Areas. Lastly, Rhode Island committed to continued evaluation of other possible control measures that would reduce haze-causing emissions in consultation with other MANE-VU states. Thus, Rhode Island met all the identified reasonable measures requested during the first implementation period. The submittal also includes periodic emission data that demonstrate a decrease in VOCs, NO X , PM and SO 2 emissions throughout the state.

The EPA proposes to find that Rhode Island 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 40 CFR 51.308(g)(4), Rhode Island provides a summary of emissions of NO X , SO 2 , PM 10 , PM 2.5 , VOCs, and NH 3 from all sources and activities, including from point, nonpoint, nonroad mobile, and onroad mobile sources, for the time period from 2002 to 2017, based on emission inventory information submitted pursuant to the AERR in 40 CFR part 51, subpart A. With respect to sources that report directly to EPA, Rhode Island also included AMPD state summary data for SO 2 and NO X emissions for 2016 through 2019. The reductions achieved by Rhode Island emission control measures are seen in the emissions inventory.

Based on Rhode Island's SIP submittal, the State experienced a 50% NO X emissions reduction from 2002 to 2017. These reductions are largely from the nonroad and onroad mobile sectors which account for 15,545 tons of NO X reduction. As a result of Federal rules to reduce emissions from nonroad vehicles and equipment, new engine standards for nonroad vehicles and equipment have driven these reductions in the nonroad sector. Examples of regulatory programs that have reduced, and/or will continue to reduce, emissions from nonroad vehicles and equipment include Control of Emissions of Air Pollution from Nonroad Diesel Engines and Fuel, 87 Control of Emissions from Air Pollution from Locomotive Engines and Marine Compression-Ignition Engines Less Than 30 Liters Per Cylinder, 88 and Control of Emissions from Nonroad Spark-Ignition Engines and Equipment. 89 Onroad mobile emission reductions are due in part to Rhode Island's adoption of more stringent motor vehicle emission standard regulations. 90 These SIP-approved standards ensure that vehicles sold in the state meet increasingly stringent emissions requirements through time, driving emissions reductions in the onroad sector. Furthermore, NO X 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.

Table 4-1 of Rhode Island's SIP submittal shows nonpoint emissions doubling from 2008 to 2011. Starting in 2008, marine vessels and underway rail emissions were included in the NEI nonpoint data category instead of the nonroad data category. However, in more recent years these nonroad sources are displaying decreases due to the above-mentioned Federal rules for new engine standards for nonroad vehicles and equipment. Most other nonpoint area source NO X emissions, approximately 75 percent, are from residential and commercial natural gas fuel combustion for heating purposes. Additional area source NO X emissions are from distillate fuel combustion, residential wood burning, prescribed burning and forest fires. Increases in emissions from 2011 to 2014 are due to increases in natural gas consumption and EPA methodology changes for fuel combustion emissions from boilers and engines, and for wildfires and prescribed burning.

Emissions of SO 2 have shown a significant decline of 90% in Rhode Island over the period 2002 to 2017. The reduction in point source emissions is primarily due to the revision to 250-RICR-120-05-8, Sulfur Content of Fuels which, as described previously in this notice, phased in an approach for requiring reduced sulfur content in fuel. The emission decreases in the nonroad sector from 2002 to 2008 are partly due to EPA moving the marine vessels and railroad emissions from the nonroad sector to the nonpoint sector. Subsequently, decreases in nonpoint sector emissions are mostly due to Federal rules that reduced sulfur content in nonroad mobile diesel fuel and to increased use of low sulfur distillate oil for heating. 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 SO 2 emissions reductions are expected to continue.

Table 4-18 of Rhode Island's submittal shows VOC emissions from all NEI data categories for the period 2002 to 2017 in Rhode Island. VOC emissions decreased by 57%, 23,483 tons, across all NEI data categories since 2002 to 2017. Much of the decrease in VOC emissions is due to Federal and State rules for evaporative sources such as the following: portable fuel containers; architectural, industrial, and maintenance coatings; consumer products; and solvent degreasing. Evaporative VOC emissions from these types of sources are expected to continue to decline as more states adopt rules based on the Ozone Transport Commission (OTC) Model Rules. 91 Evaporative VOC emissions from onroad mobile sources have decreased due to state motor vehicle inspection and maintenance programs and the increasing prevalence of on-board refueling vapor recovery (ORVR) equipped vehicles in the fleet. VOC emissions from nonroad and onroad mobile sources are expected to continue to decrease as older, more polluting vehicles are replaced by newer, cleaner ones. Other decreases are due to state VOC RACT rules.

In Rhode Island's submittal, table 4-7 shows a summary of PM 10 emissions from all NEI data categories for the period from 2002 to 2017. In Rhode Island, PM 10 emissions steadily decreased in the point, nonpoint, and nonroad categories for this period. There was an overall reduction in PM 10 emissions of 21%. Most of this reduction came from the nonpoint category due to fuel switching from oil to natural gas. 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. The apparent increase in the onroad emissions is due to changes in emission inventory calculation methodologies, which resulted in higher particulate matter estimates.

Table 4-10 of Rhode Island's submittal shows a summary of PM 2.5 emissions from all NEI data categories for the period from 2002 to 2017. Overall, PM 2.5 emissions increased by 41%. However, much of this increase is due to Rhode Island not submitting PM 2.5 data for point and nonpoint sources in 2002. Rhode Island submitted total particulate matter data in 2002 which was augmented by EPA for PM 2.5 . Additionally, the data in Table 4-10 do not accurately reflect the reduction in PM 2.5 emissions anticipated based on the large number of point sources that would be in the nonpoint category for fuel combustion switching from oil to natural gas. The variations in the onroad and nonpoint category are due to changes in emission inventory calculation methodologies, which resulted in higher particulate matter estimates in some years. PM 2.5 emissions steadily decreased in the nonroad category for this period. This reduction can likely be attributed to new Federal engine standards for nonroad vehicles and equipment. 92

Table 4-21 of Rhode Island's submission shows ammonia (NH 3 ) emissions from all NEI data categories for the period 2002 to 2017. 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 a reduction in the point source category and little change in the nonroad category.

The EPA is proposing to find that Rhode Island has satisfied the requirements of 40 CFR51.308(g)(4) by providing emissions information for NO X , SO 2 , PM 10 , PM 2.5 , VOC, and NH 3 broken down by type of source.

The emissions trend data in the SIP submission support Rhode Island's assessment that no significant increase of haze-causing pollutant emissions has occurred in the state during the reporting period and that changes in emissions have not limited or impeded progress in reducing pollutant emissions and improving visibility. The EPA is proposing to find that Rhode Island has met the requirements of 40 CFR51.308(g)(5).

Section 169A(d) of the Clean Air Act requires states to consult with FLMs before holding the public hearing on a proposed regional haze SIP, and to include a summary of the FLMs' conclusions and recommendations in the notice to the public. In addition, section 51.308(i)(2)'s FLM consultation provision requires a state to provide FLMs with an opportunity for consultation that is early enough in the state's policy analyses of its emission reduction obligation so that information and recommendations provided by the FLMs can meaningfully inform the state's decisions on its long-term strategy. If the consultation has taken place at least 120 days before a public hearing or public comment period, the opportunity for consultation will be deemed early enough, 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. Rhode Island participated in these consultation meetings and calls. 93

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. 94 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 NO X , PM 10 , SO 2 , and SO 4 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 one facility in Rhode Island in this letter; Dominion Energy Manchester Street, INC. 95 As explained in the discussion for Ask 1, Manchester Street facility operates three 119.05 MW combustion turbines capable of burning #2 fuel oil and natural gas and is equipped with an SCR system. The operating permit of this facility limits NO X emissions to 47.5 and 78.78 lb/hr for natural gas and #2 fuel oil, respectively, and limits SO 2 emissions to 73.13 and 63.8 lb/hr for natural gas and #2 fuel oil, respectively. 96 The units are required to comply with all applicable Federal and State regulations as identified in the enforceable permit.

On July 30, 2024, RIDEM OAR sent its pre-proposal draft SIP revision 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. Rhode Island received responses from the NPS and the USFS. The NPS stated that it “appreciate[d RIDEM's] work for clean air and clear views across the region and d[id] not intend to provide further conclusions and recommendations on the Rhode Island Regional Haze SIP revision.” The NPS further stated that “emissions from Rhode Island facilities have not been identified as impairing visibility at any National Park Service managed Class I areas.”  97 The USFS also responded by noting its satisfaction with the draft proposal and acknowledging the opportunity to work closely with Rhode Island through the initial evaluation, development, and subsequent review of this plan. 98

Rhode Island held a public comment period for this Regional Haze SIP revision. On January 24, 2025, RIDEM issued a notice of public hearing and comment and the availability of the draft Regional Haze SIP revision for 2018-2028 on RIDEM's web page. The notice announced the opportunity to submit written comments or requests for public hearing until February 28, 2025. No comments or requests for a public hearing were received.

For the reasons stated above, the EPA proposes to find that Rhode Island has satisfied the requirements under CAA section 169A(d) and 40 CFR 51.308(i) to consult with the FLMs on its regional haze SIP for the second implementation period.

Rhode Island's March 7, 2025, 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 40 CFR51.308(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 40 CFR51.308(g).

On October 1, 2015, EPA promulgated a revision to the ozone NAAQS (2015 ozone NAAQS), lowering the level of both the primary and secondary standards to 0.070 parts per million (ppm). Section 110(a)(1) of the CAA requires states to submit, within 3 years after promulgation of a new or revised standard, SIPs meeting the applicable requirements of section 110(a)(2). On September 23, 2020, RIDEM submitted a revision to its SIP addressing the infrastructure requirements of CAA sections 110(a)(1) and 110(a)(2) for the 2015 ozone NAAQS.

Effective November 15, 2021, EPA approved Rhode Island's submittal as adequately addressing the following CAA elements or portions thereof: 110(a)(2)(A); (B); (C); (D) except (D)(i)(I) and (D)(i)(II)-visibility protection; (E); (F); (G); (J); (K); (L); (M) and disapproved for element (H)- future SIP revisions. This action did not include three interstate transport provisions under section 110(a)(2)(D)(i), namely the “good neighbor” provisions at section 110(a)(2)(D)(i)(I) (also known as the State's Transport SIP or “prongs 1 and 2”) and the provision relating to visibility protection at 110(a)(2)(D)(i)(II) (also known as “prong 4”).

Shortly after, effective January 10, 2022, EPA approved Rhode Island's submittal as adequately addressing the “good neighbor” provisions at section 110(a)(2)(D)(i)(I). With the proposed approval of Rhode Island's Regional Haze plan for the second implementation period, today's action is proposing approval of the remaining element of Rhode Island's September 2020 ISIP for addressing requirements under section 110(a)(2)(D)(i)(II)—visibility protection, also known as “prong 4”.

CAA Section 110(a)(2)(D)(i)(II), prong 4, requires SIPs to contain adequate provisions to prohibit emissions in amounts that will interfere with measures required to be included in the applicable implementation plan for any other state under part C of the Act to protect visibility. EPA issued guidance on infrastructure SIPs in a September 13, 2013, memorandum titled “Guidance on Infrastructure State Implementation Plan (SIP) Elements under Clean Air Act sections 110(a)(1) and 110(a)(2)” (“2013 Guidance”). The 2013 Guidance states that these prong 4 requirements can be satisfied by approved SIP provisions that the EPA has found to adequately address any contribution of that state's sources that impact the visibility program requirements in other states. 99

The 2013 Guidance lays out how a state's infrastructure SIP may satisfy prong 4. In the second planning period, confirmation that the state has a fully approved regional haze SIP that fully meets the requirements of 40 CFR 51.308 will satisfy the requirements of prong 4. 100 A fully approved regional haze SIP 101  will ensure that emissions from sources under an air agency's jurisdiction are not interfering with measures required to be included in other air agencies' plans to protect visibility.

In the second planning period, EPA's Regional Haze regulations under 40 CFR 51.308(f) require that a State consider the emission reduction measures identified by other States as being necessary to make reasonable progress towards meeting the national visibility goal in Class I Federal areas. Specifically, the regulations also require a State to include in its Regional Haze SIP all measures agreed to during that process or measures that will provide equivalent visibility improvement. 40 CFR 51.308(f)(2)(ii). Thus, in meeting the requirements of 40 CFR 51.308(f), an approved regional haze SIP meeting the requirements of 40 CFR 51.308(f)(2)(ii) will ensure that emissions from sources under an air agency's jurisdiction are not interfering with measures required to be included in other air agencies' plans to protect visibility and will, therefore, satisfy Prong 4.

As discussed above, Rhode Island is a member of the MANEVU RPO and participated in the RPO's regional approach to identifying emission reduction measures necessary to make reasonable progress towards the national visibility goal in the MANEVU Class I areas. That process also included consultations with States in other RPOs, and Rhode Island did not receive any requests from non-MANEVU States to consider additional measures to address visibility impairment in Class I areas outside the MANEVU States. In today's action, EPA has proposed to approve Rhode Island's submittal as meeting the requirements of 40 CFR 51.308(f) for the second planning period. See Section IV.E.c. Accordingly, EPA also proposes that Rhode Island meets the visibility protection requirements of CAA § 110(a)(2)(D)(i)(II) for the 2015 ozone NAAQS.

The EPA is proposing to approve the “Rhode Island Regional Haze State Implementation Plan Revision for the Second Implementation Period (2018-2028)”, final submittal dated March 2025 and submitted to EPA on March 7, 2025, as satisfying the regional haze requirements for the second implementation period contained in 40 CFR 51.308(f), (g), and (i). Additionally, EPA is proposing approval of the remaining element of Rhode Island's September 23, 2020, ISIP for addressing requirements under section 110(a)(2)(D)(i)(II)—visibility protection, also known as “prong 4”.

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 Rhode Island 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).

Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA.

On April 30, 2025, the Connecticut Department of Energy and Environmental Protection (CT DEEP) submitted a revision to its State Implementation Plan for sections 22a-174-24 and 22a-174-44 of the Regulations of Connecticut State Agencies (RCSA). The revision consists of adding the 0.070 parts per million ozone standard in RCSA 22a-174-24 and clarifying the volatile organic compound calculation methods available for adhesive and sealant products in RCSA 22a-174-44.

Section 109 of the Clean Air Act (CAA) directs EPA to establish National Ambient Air Quality Standards requisite to protect public health with an adequate margin of safety (primary standard) and for the protection of public welfare (secondary standard). Sections 109(d)(1) of the CAA requires EPA to complete a thorough review of the NAAQS at 5-year intervals and promulgate new standards when appropriate. Additionally, Section 107 of the CAA requires the establishment of air quality control regions for the purpose of implementing the NAAQS.

On October 26, 2015, EPA revised both the primary and secondary NAAQS for ozone to a level of 0.070 parts per million (ppm) to provide increased protection of public health and the environment ( See 80 FR 65292). This final ozone rule became effective on December 28, 2015.

The Ozone Transport Commission (OTC) is a multi-state organization created under Section 184 of the Clean Air Act. The OTC is responsible for advising EPA on developing and implementing regional solutions to the ground-level ozone problem in the Northeast and Mid-Atlantic regions. The OTC committees develop consensus-based model rules and guidelines for use by their members at their discretion. The OTC itself is not a regulatory authority and does not adopt these as requirements for the region. Each OTC member that opts to adopt a model rule or guideline may modify it according to its own circumstances, and each OTC member is the primary authority on interpreting its rules and guidelines within its jurisdiction.

On December 7, 2006, the OTC issued the OTC Model Rule of Adhesives and Sealants. 1 The provisions of this model rule limit emissions of VOCs from adhesives, sealants and primers. The model rule achieves VOC reductions through two basic components: sale and manufacture restrictions that limit the VOC content of specified adhesives, sealants and primers sold in the state; and use restrictions that apply primarily to commercial/industrial applications. By reducing the availability of higher VOC content adhesives and sealants within the state, the sales prohibition is also intended to address adhesive and sealant usage at area sources. Emissions from residential use of regulated products are addressed through the sales restrictions and simple use provisions. The model rule is based on a 1998 reasonable available control technology (RACT) determination prepared by the California Air Resources Board (CARB). 2 On April 2, 2024, the OTC issued corrective/clarifying revisions to the model rule to clarify the VOC calculation methods available for adhesive and sealant products. 3

Connecticut's April 30, 2025, SIP submittal includes revisions to RCSA section 22a-174-24, “Connecticut primary and secondary ambient air quality standards.” Specifically, CT DEEP is revising subsection (i) of section 22a-174-24 by adding subdivision (3) into Connecticut's SIP. This regulation has been revised to maintain consistency between the Connecticut AAQS and EPA's NAAQS for ozone. Specifically, Connecticut adopted the 2015 ozone primary and secondary 8-hour standards of 0.070 parts per million. A copy of CT DEEP's revisions to RCSA section 22a-174-24 is located in the docket of this proposed rulemaking. 4

Connecticut's air quality standards rule, RCSA section 22a-174-24, as well as amendments to this rule, have been previously approved into the Connecticut SIP, with the most recent approval occurring on June 24, 2015 ( See 80 FR 36242). EPA has reviewed Connecticut's revisions to its ambient air quality standards, definitions, and references and has determined they are consistent with the federal NAAQS in 40 CFR part 50. Connecticut's revised RCSA section 22a-174-24 includes additional and more stringent air quality standards than the previous SIP-approved version of this rule. Thus, the revised RCSA section 22a-174-24 satisfies the anti-backsliding requirements in Section 110(l) of the CAA and we are proposing to approve Connecticut's revised rule into the Connecticut SIP.

Connecticut's April 30, 2025, SIP submittal includes revisions to RCSA section 22a-174-44, “Adhesives and sealants.” Specifically, CT DEEP is revising subdivision (2) of subsection (e) of section 22a-174-44 in Connecticut's SIP. This regulation has been revised to correct the VOC calculation methods for adhesive and sealant products. Specifically, the correction clarifies the VOC content determinations for low-solids adhesives, sealants, adhesive primers and sealant primers as set out in subparagraph (C) of subdivision (2). Additionally, this correction clarifies the calculation methodology for non-low solids adhesives, sealants, adhesive primers and sealant primers. A copy of CT DEEP's revisions to RCSA section 22a-174-44 is located in the docket of this proposed rulemaking. 5

Connecticut's adhesives and sealants rule, RCSA section 22a-174-44, has been previously approved into the Connecticut SIP on June 9, 2014 ( See 79 FR 32873). RCSA section 22a-174-44 is based on the OTC Model Rule for Adhesives and Sealants and includes the calculation methods available for adhesive and sealant products from the OTC Model Rule. EPA has reviewed Connecticut's revisions to its adhesives and sealants rule and has determined they are consistent with the revised April 2, 2024, OTC Model Rule for Adhesives and Sealants. EPA is proposing to approve Connecticut's revised rule into the Connecticut SIP.

EPA is proposing to approve Connecticut's April 30, 2025 SIP revision to their RCSA 22a-174-24 and 22a-174-44, and incorporate each into the Connecticut SIP. EPA is soliciting public comments on the issues discussed in this notice or on other relevant matters. These comments will be considered before taking final action. Interested parties may participate in the Federal rulemaking procedure by submitting written comments to this proposed rule by following the instructions listed in the ADDRESSES section of this Federal Register .

In this rule, the EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference changes to Connecticut RCSA sections 22a-174-24 and 22a-174-44 as adopted on April 2, 2025, and described in section II. of this preamble. The changes primarily update the AAQS to match the primary and secondary NAAQS for ozone and clarifies VOC calculation methods for adhesive and sealant products. The EPA has made, and will continue to make, these documents generally available through https://www.regulations.gov and at the EPA Region 1 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

Under the Clean Air Act, the Administrator is required to approve a SIP submission that complies with the provisions of the Clean Air Act and applicable Federal regulations. See 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 Clean Air Act. Accordingly, this proposed action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this 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);

• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866;

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. );

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. );

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Public Law 104-4);

• Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);

• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and

• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the rule does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

On April 15, 2024, DNREC submitted a revision to the State's SIP. This revision is a LMP for the second 10-year maintenance period for the 2006 24-hour PM 2.5 NAAQS for the New Castle County portion of the Philadelphia-Wilmington, PA-NJ-DE area. The Philadelphia Area is comprised of New Castle County in Delaware; Burlington, Camden, and Gloucester Counties in New Jersey; and Bucks, Chester, Delaware, Montgomery, and Philadelphia Counties in Pennsylvania. This action is expected to ensure that the State of Delaware meets CAA requirements.

Under section 109 of the CAA, the EPA has established NAAQS for certain pervasive air pollutants (referred to as “criteria pollutants”) and conducts periodic reviews of the NAAQS to determine whether they should be revised or whether new NAAQS should be established. The EPA sets the NAAQS for criteria pollutants at levels required to protect public health and welfare. 1 The EPA's particulate matter standards address particles with diameters that are generally two and half micrometers or smaller (fine particulate matter or PM 2.5 ) and particles with diameters that are generally 10 micrometers or smaller (PM 10 ). PM 2.5 is one of the ambient pollutants for which the EPA has established health-based standards.

Fine particulate matter contributes to effects that are harmful to human health and the environment, including premature mortality, aggravation of respiratory and cardiovascular disease, decreased lung function, visibility impairment, and damage to vegetation and ecosystems. Individuals particularly sensitive to PM 2.5 exposure include older adults, people with heart and lung disease, and children. See 78 FR 3086 at 3088 (January 15, 2013). PM 2.5 can be emitted directly into the atmosphere as a solid or liquid particle (primary PM 2.5 or direct PM 2.5 ) or can be formed in the atmosphere (secondary PM 2.5 ) as a result of various chemical reactions among precursor pollutants such as nitrogen oxides (NO X ), sulfur dioxide (SO 2 ), volatile organic compounds (VOCs), and ammonia (NH 3 ). 2

On July 18, 1997 (62 FR 38652), the EPA revised the NAAQS for particulate matter to add new standards for PM 2.5 . The Agency established primary and secondary annual and 24-hour standards for PM 2.5 . The annual standard was set at 15.0 micrograms per cubic meter (µg/m 3 ) based on a 3-year average of annual mean PM 2.5 concentrations, and the 24-hour (daily) standard was set at 65 µg/m 3 based on the 3-year average of the annual 98th percentile values of 24-hour PM 2.5 concentrations at each population-oriented monitor within an area. 3

On October 17, 2006 (71 FR 61144), the EPA promulgated the 2006 PM 2.5 NAAQS. It retained the annual average NAAQS at 15.0 µg/m 3 but lowered the level of the 24-hour PM 2.5 NAAQS to 35 µg/m 3 based on a 3-year average of the annual 98th percentile values of 24-hour concentrations. 4

On December 14, 2012, the EPA promulgated the 2012 PM 2.5 NAAQS, including lowering the annual standard to 12.0 µg/m 3 based on a 3-year average of annual mean PM 2.5 concentrations. The EPA maintained the 24-hour standard of 35 µg/m 3 based on a 3-year average of the 98th percentile of 24-hour concentrations. See 78 FR 3086 (January 15, 2013).

On February 7, 2024, the EPA revised the NAAQS for particulate matter to add new standards for PM 2.5 . The EPA strengthened the level of the annual primary PM 2.5 standard from 12.0 µg/m 3 to 9.0 µg/m 3 . The EPA retained the primary and secondary 24-hour PM 2.5 standards, secondary annual PM 2.5 standard, and primary and secondary PM 10 standards. See 89 FR 16202 (March 6, 2024).

Following promulgation of a new or revised NAAQS, the EPA is required by CAA section 107(d) to designate areas throughout the nation as attaining or not attaining the NAAQS. On November 13, 2009 (74 FR 58688), the EPA designated the Philadelphia Area as nonattainment for the 2006 24-hour PM 2.5 NAAQS.

Initially, the EPA did not assign classifications for PM 2.5 for the 2006 24-hour NAAQS ( e.g. marginal, moderate, etc.). Subsequently, on January 4, 2013, the Court of Appeals for the District of Columbia remanded the EPA's implementation rule as a result of Natural Resources Defense Council v. EPA, 706 F.3d 428 (D.C. Cir. 2013), regarding the failure of the EPA to assign classifications for PM 2.5 for the 2006 24-hour NAAQS. The Court concluded that the EPA had improperly based the 2007 implementation rule for the 2006 24-hour PM 2.5 NAAQS solely upon the requirements of Title I, part D, subpart 1 of the CAA, and had failed to address the requirements of part D, subpart 4. In response to the court decision, the EPA subsequently assigned classifications to the applicable areas. On April 25, 2014, the EPA finalized a rule identifying the classification of all PM 2.5 areas currently designated nonattainment for the 2006 24-hour PM 2.5 NAAQS as “Moderate” (79 FR 31566, June 2, 2014).

On November 27, 2012, the State of Delaware submitted to the EPA a redesignation request and maintenance plan for the New Castle County portion of the Philadelphia Area. The EPA redesignated the New Castle County portion of the Philadelphia Area from nonattainment to attainment for the 2006 24-hour PM 2.5 NAAQS and approved the maintenance plan for the first 10-year maintenance period effective September 4, 2014 (79 FR 45350, August 5, 2014). The first 10-year maintenance period for the New Castle County portion of the Philadelphia Area ended on September 4, 2024, and the Area's second 10-year maintenance period, which is the subject of this proposed rulemaking, extends through September 4, 2034.

Section 107(d)(3)(E) of the CAA sets out the requirements for redesignating a nonattainment area to attainment. One of the criteria for redesignation is to have an approved maintenance plan under section 175A of the Act. Section 175A requires that nonattainment areas seeking redesignation to attainment submit “a revision of the applicable state implementation plan to provide for the maintenance of the [NAAQS] for such air pollutant in the area concerned for at least 10 years after the redesignation.” Pursuant to section 175A(b), eight years into the first maintenance period, the applicable state or local agency must submit a second maintenance plan demonstrating that the area will continue to attain for the following 10-year period. On September 4, 1992, the EPA issued guidance on the content of a maintenance plan (Memorandum from John Calcagni, Director, Air Quality Management Division, entitled “Procedures for Processing Requests to Redesignate Areas to Attainment,” (hereinafter referred to as the “Calcagni Memorandum”))  5 which explained that states may meet this requirement to “provide for the maintenance of the NAAQS” by using projected emissions inventories or air quality modeling showing continued maintenance until the end of the relevant maintenance period. The EPA clarified in subsequent guidance memoranda that rather than using air quality modeling or an emission inventory projection, certain areas could meet the CAA section 175A requirement to provide for maintenance by demonstrating that the area's design value was well below the NAAQS and that the historical stability of the area's air quality levels showed that the area was unlikely to violate the NAAQS in the future. 6 Design values (DV) for the 2006 24-hour PM 2.5 NAAQS are calculated using the 3-year average of annual 98th percentile 24-hour average PM 2.5 mass concentration values recorded at each eligible monitoring site.

Most recently, in October 2022, the EPA released guidance extending this streamlined option for demonstrating maintenance under CAA section 175A to certain PM 2.5 areas, titled “Guidance on the Limited Maintenance Plan Option for Moderate PM 2.5 Nonattainment Areas and PM 2.5 Maintenance Areas” (PM 2.5 LMP Guidance). 7

The EPA refers to this streamlined demonstration of maintenance as a limited maintenance plan or LMP. The EPA has interpreted CAA section 175A as permitting this option because section 175A does not define how areas may demonstrate maintenance, and in the EPA's experience with implementing the various NAAQS, areas that qualify for an LMP and have approved LMPs, have rarely, if ever, experienced subsequent violations of the NAAQS. As noted in the PM 2.5 LMP Guidance, states seeking an LMP must still submit the other maintenance plan elements outlined in the Calcagni Memorandum, including an attainment emissions inventory, provisions for the continued operation of the ambient air quality monitoring network, verification of continued attainment, and a contingency plan in the event of a future violation of the NAAQS.

The PM 2.5 LMP Guidance describes a process for states to demonstrate that an area qualifies for an LMP by showing that, based on recent measured air quality, the area is unlikely to violate the NAAQS in the future. The PM 2.5 LMP Guidance relies on the critical design value (CDV) concept. This guidance describes a process for a PM 2.5 area to qualify for an LMP by showing that the area's average design value (ADV) for each site in the area (based upon the most recent five design values as calculated)  8 is at or below the CDV. The CDV is an indicator of the likelihood of future violations of the NAAQS in an area given the area's current ADV and its historical variability. The PM 2.5 LMP Guidance provides a means for calculating the CDV for an area (or monitoring site). The CDV calculation for a monitoring site involves parameters including: (1) the level of the relevant NAAQS;  9 (2) the coefficient of variation (CV) of recent design values measured at that site; and (3) a statistical parameter t c (critical t-value) corresponding to a 10 percent probability of exceedance, such that sites with historically high variability in design values result in a lower (or more stringent) CDV. 10 The CDV is the highest average design value an area could have before it may experience a future exceedance of the NAAQS with a certain probability—in the case of the PM 2.5 LMP Guidance, a probability of one in ten. 11 Therefore, if an area's current ADV is less than the area's CDV, that area has less than a ten percent probability of exceeding the NAAQS in the future. The eligibility calculations for the CDV demonstration are shown in table 1 in this document.

Per the EPA's transportation conformity regulations, a LMP must also “demonstrate that it would be unreasonable to expect that such an area would experience enough motor vehicle emissions growth for a NAAQS violation to occur.”  12 For further discussion of transportation conformity, see section III of this document.

On April 15, 2024, the EPA received Delaware's second 10-year maintenance plan SIP submission for the 2006 24-hour PM 2.5 NAAQS for the New Castle County portion of the Philadelphia Area.

As discussed in section I.C. of this document, one way for an area to qualify for an LMP is to show that the area's ADV (based upon the most recent five years of monitoring data) is at or below the CDV. The New Castle County portion of the Philadelphia Area includes five ambient air monitoring sites for the 24-hour PM 2.5 NAAQS: the Bellefonte I site (AQS 10-003-1003), the Lums Pond site (AQS 10-003-1007), the RT 9 site (AQS 10-003-1008), the Newark site (AQS 10-003-1012), and the MLK site (AQS 10-003-2004). Due to multiple technical and operational issues from 2014-2020, four out of the five PM 2.5 monitors were unable to meet the data completeness requirement  13 for multiple years (Bellefonte, RT 9, Newark, and Lums Pond). For the New Castle County portion of the Philadelphia Area, Delaware calculated the ADV by averaging the most recent five consecutive 3-year averages (design values) of monitoring data at the time of submission, from 2014 to 2020. 14 Delaware is in the process of transitioning from manual to continuous monitors, which are expected to reduce monitor downtime due to technical/mechanical issues. 15 The MLK monitoring station meets the EPA's PM 2.5 design value completeness rules for 2014-2020 as the EPA allows the collocated Federal equivalent methods (FEM) to fill in when the primary monitor is down. 16 Collocated refers to two or more air samplers, analyzers, or other instruments that are operated simultaneously while located side by side, separated by a distance that is large enough to preclude the air sampled by any of the devices from being affected by any of the other devices, but small enough so that all devices obtain identical or uniform ambient air samples that are equally representative of the general area in which the group of devices is located. Additionally, FEM is a method of measuring the concentration of an air pollutant in the ambient air that has been designated as an equivalent method in accordance with 40 CFR part 53. A Federal reference method (FRM) is a method of sampling and analyzing the ambient air for an air pollutant that is specified as a reference method in an appendix to 40 CFR part 50, or a method that has been designated as a reference method in accordance with 40 CFR part 53. Data from these monitors are measured using the EPA approved methods including FEM and FRM.

Since each design value is calculated by averaging three years of the 98th percentile of 24-hour average, the average of the five consecutive 3-year design values includes data from a seven-year period (2014-2020). 17 Table 2 in this document presents five 3-year design values for the 24-hour PM 2.5 NAAQS for the New Castle County portion of the Philadelphia Area that were available to Delaware while developing the LMP. Due to incomplete data, only the MLK monitoring site is used to calculate eligibility for the LMP. This is consistent with the PM 2.5 LMP Guidance, however, ADVs and CDVs were calculated for the monitors with incomplete data for reference. The ADV of the MLK site is 20 µg/m 3 .

Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA.

The CAA requires the EPA to establish primary and secondary NAAQS for certain pervasive pollutants that “may reasonably be anticipated to endanger public health and welfare.” The primary NAAQS is designed to protect public health with an adequate margin of safety, and the secondary NAAQS is designed to protect public welfare and the environment. The EPA has set NAAQS for six common air pollutants, referred to as criteria pollutants, including ozone. The NAAQS represent the air quality levels an area must meet to comply with the CAA. Ozone is a gas composed of three oxygen atoms and is created by chemical reactions between volatile organic compounds (VOC) and oxides of nitrogen (NO X ) in the atmosphere in the presence of sunlight. Ground-level ozone can harm human health and the environment. Ozone exposure has been associated with increases in susceptibility to respiratory infections, medication use by asthmatics, doctor visits, and emergency department visits and hospital admissions for individuals with respiratory disease. Ozone exposure may also contribute to premature death, especially in people with heart and lung disease.

In October 2015, the EPA strengthened the primary and secondary eight-hour ozone NAAQS from 0.075 parts per million (ppm) to 0.070 ppm (“2015 ozone NAAQS”). 1 In accordance with section 107(d) of the CAA, the EPA must designate an area “nonattainment” if it is violating the NAAQS or if it is contributing to a violation of the NAAQS in a nearby area. With respect to the ozone NAAQS, the EPA further classifies nonattainment areas as “Marginal,” “Moderate,” “Serious,” “Severe,” or “Extreme,” depending upon the ozone design value for an area. 2 As a general matter, higher classified ozone nonattainment areas are subject to additional CAA planning requirements than lower classified areas but are allowed more time to demonstrate attainment of the ozone NAAQS. 3

Effective on August 3, 2018, the EPA designated 52 areas throughout the country as nonattainment for the 2015 ozone NAAQS. 4 In a separate action, the EPA assigned classification thresholds and attainment dates based on the severity of an area's ozone problem, determined by the area's design value (DV). 5 6 The EPA established the attainment date for Marginal, Moderate, and Serious nonattainment areas as 3 years, 6 years, and 9 years, respectively, from the effective date of the final designations. Thus, the attainment date for Marginal nonattainment areas for the 2015 ozone NAAQS was August 3, 2021, the attainment date for Moderate areas was August 3, 2024, and the attainment date for Serious areas is August 3, 2027. On October 7, 2022, the EPA determined that 22 areas including the Greater Connecticut area, did not attain the standards by the Marginal attainment date, 7 and these areas were reclassified as Moderate by operation of law. The Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe, which are the two tribal territories being addressed in this proposed action, are located within the boundaries of the Greater Connecticut nonattainment area.

The EPA is required to determine whether areas designated nonattainment for an ozone NAAQS attained the standard by the applicable attainment date, and to take certain steps for areas that failed to attain. 8 The EPA's determination of attainment for the 2015 ozone NAAQS is “based on a nonattainment area's DV as of the attainment date.”

The 2015 ozone NAAQS is met at an EPA regulatory monitoring site when the DV does not exceed 0.070 ppm. For the Moderate nonattainment areas for the 2015 ozone NAAQS addressed in this action, the attainment date was August 3, 2024. Because the DV is based on the three most recent, complete calendar years of data, the EPA's determinations for each Moderate 2015 ozone NAAQS nonattainment area under CAA section 181(b)(2) are based upon the complete, quality-assured, and certified ozone monitoring data from calendar years 2021, 2022, and 2023.

At the request of CT DEEP, the Greater Connecticut area was voluntarily reclassified from Moderate to Serious for the 2015 ozone NAAQS before the August 3, 2024, nonattainment date. 9 However, the tribal portions of the Greater Connecticut area remained classified as Moderate. The entire Greater Connecticut area, including the tribal portions, factually failed to attain the 2015 ozone NAAQS. This finding was not altered by CT DEEP's Exceptional Event (EE) demonstration discussed in Section I.B. of this action. EPA is proposing to determine that the tribal portions of the Greater Connecticut area failed to attain and will be reclassified as Serious for the 2015 ozone NAAQS. If the EPA determines that a nonattainment area classified as Moderate failed to attain by the attainment date, CAA section 181(b)(2)(B) requires the EPA to publish a document in the Federal Register , identifying each such area and identifying the applicable reclassification.

The statutory authority for these determinations is provided by the CAA, as amended (42 U.S.C. 7401 et seq. ). Relevant portions of the CAA include, but are not necessarily limited to, sections 181 and 182.

As noted earlier, CAA section 107(d) provides that when the EPA establishes or revises a NAAQS, the agency must designate areas of the country as nonattainment, attainment, or unclassifiable based on whether an area is not meeting (or contributing to air quality in a nearby area that is not meeting) the NAAQS, meeting the NAAQS, or cannot be classified as meeting or not meeting the NAAQS, respectively. Subpart 2 of part D of title I of the CAA governs the classification, state planning, and emissions control requirements for any areas designated as nonattainment for a revised primary ozone NAAQS. In particular, CAA section 181(a)(1) requires each area designated as nonattainment for a revised ozone NAAQS to be classified at the same time as the area is designated based on the extent of the ozone problem in the area (as determined based on the area's design value). Classifications for ozone nonattainment areas range from “Marginal” to “Extreme” based on the severity of the area's air quality problem.

CAA section 182 provides the specific attainment planning and additional requirements that apply to each ozone nonattainment area based on its classification. CAA section 182, as interpreted by the EPA's implementing regulations in the Code of Federal Regulations (CFR) at 40 CFR 51.1308 through 51.1317, also establishes the timeframes by which air agencies must submit and implement SIP revisions to satisfy the applicable attainment planning elements, and the timeframes by which nonattainment areas must attain the 2015 ozone NAAQS. For reclassified areas, CAA section 182(i) provides that the Administrator may adjust applicable deadlines other than attainment dates if such adjustment is necessary or appropriate to assure consistency among the required submissions.

Section 181(b)(2)(A) of the CAA requires that within 6 months following the applicable attainment date, the EPA shall determine whether an ozone nonattainment area attained the ozone standard based on the area's DV as of that date. For nonattainment areas that the EPA determines have not timely attained, CAA section 181(a)(5) gives the EPA the discretion to grant a 1-year extension of the attainment date for qualifying areas upon application by any state. In the event an area fails to attain the ozone NAAQS by the applicable attainment date and is not granted a 1-year attainment date extension, CAA section 181(b)(2)(A) requires the EPA to make the determination that an ozone nonattainment area failed to attain the ozone standard by the applicable attainment date, and requires the area to be reclassified by operation of law to the higher of: (1) the next higher classification for the area, or (2) the classification applicable to the area's design value as of the determination of failure to attain. Section 181(b)(2)(B) of the CAA required the EPA to publish the determination of failure to attain and accompanying reclassification in the Federal Register no later than 6 months after the attainment date, which in the case of the two tribal territories located in the Greater Connecticut nonattainment area, was February 3, 2025.

Once an area is reclassified, the state is required to submit certain SIP revisions in accordance with its more stringent classification. The SIP revisions are intended to, among other things, demonstrate how the area will attain the NAAQS as expeditiously as practicable, but no later than August 3, 2027, the Serious area attainment date for the 2015 ozone NAAQS. According to CAA section 182(i), a state with a reclassified ozone nonattainment area must submit the applicable attainment plan requirements “according to the schedules prescribed in connection with such requirements” in CAA section 182(c) for Serious areas, but the EPA “may adjust any applicable deadlines (other than attainment dates) to the extent such adjustment is necessary or appropriate to assure consistency among the required submissions.” EPA has addressed the SIP revision and implementation deadlines for newly reclassified Serious areas, as well as the continued applicability of Moderate area requirements that these areas may not yet have met, in a separate rulemaking. 10

Under the CAA and Tribal Authority Rule (TAR), Tribes may, but are not required to, submit implementation plans to the EPA for approval. 11 Accordingly, for the Greater Connecticut nonattainment area, the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe would not be required to submit any tribal implementation plan (TIP) revisions applicable to the Serious areas established in CAA section 182(c) and in the 2015 ozone NAAQS SIP Requirements Rule.

As discussed earlier, the 2015 ozone NAAQS is attained at a site when the design value at each ambient air quality monitoring site within the area does not exceed 0.070 ppm. The rounding convention in Appendix U dictates that concentrations shall be reported in “ppm” to the third decimal place, with additional digits to the right being truncated. Thus, a computed 3-year average ozone concentration of 0.071 ppm is greater than 0.070 ppm and would exceed the standard, but a design value of 0.0709 is truncated to 0.070 and attains the 2015 ozone NAAQS.

The EPA's determination of attainment by the Moderate attainment date of August 3, 2024, is based upon hourly ozone concentration data for calendar years 2021, 2022 and 2023 that have been collected and quality-assured in accordance with 40 CFR part 58 and reported to the EPA's Air Quality System (AQS) database. 12

Exceptional events are unusual or naturally occurring events that can affect air quality but are not reasonably controllable using techniques that tribal, state or local air agencies may implement to attain and maintain the NAAQS. Exceptional events may include wildfires, high wind dust events, prescribed fires, stratospheric ozone intrusions, and volcanic and seismic activities. Under section 319(b) of the CAA, air agencies can request the exclusion of event-influenced data when “exceptional” events influence monitoring data and cause exceedances or violations of the NAAQS, and the EPA can agree to exclude these data, from the data set used for certain regulatory decisions.

On January 10, 2024, the Connecticut Department of Energy and Environmental Protection (CT DEEP) Bureau of Air Management submitted an initial notification for an intended EE demonstration, and on July 1, 2024, submitted an EE demonstration for exceedances or violations of the 2015 ozone NAAQS that occurred at the Cornwall (AQS Site ID #090050005), East Hartford (AQS Site ID #090031003), and Groton (AQS Site ID #090110124) monitoring sites in the Greater Connecticut area. CT DEEP requested that EPA exclude data for April 13-14, June 30-July 1, and July 12, 2023, at the Groton monitoring site, as well as data for July 1, 2023, at the East Hartford and Cornwall monitoring locations. The EPA's July 22, 2024, action on the demonstration affects the determinations of attainment by the attainment date for the Greater Connecticut area (including the two tribal territories). The EE initial notification, EE demonstration, the EPA's response to the initial notification, and EPA's July 22, 2024, decision on the EE demonstration are provided in the docket for this rulemaking.

The EPA is proposing this action to fulfill its statutory obligation under CAA section 181(b)(2) to determine whether the tribal portions of the Greater Connecticut area attained the 2015 ozone NAAQS as of the attainment date of August 3, 2024, and to reclassify both tribal portions of the area. The two tribal territories are governed by the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe.

The EPA evaluated air quality data to determine if the two tribal portions of the Moderate nonattainment area attained the 2015 ozone NAAQS by the attainment date of August 3, 2024. The areas' ozone design values for 2021-2023 are shown in Table 1. Based on the certified, complete data from 2021-2023, the design value for the tribal portions of the Greater Connecticut area is 0.072 ppm and the 2023 4th highest daily maximum 8-hour average is 0.071 ppm.

On July 1, 2024, CT DEEP submitted an EE demonstration. The EE demonstration proposed five days to be excluded from the 2023 ozone season. The EPA's previous action on the demonstration affects the determination of attainment by the attainment date for the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe. 13 The EE initial notification, EE demonstration, the EPA's response to the initial notification, and EPA's decision on the EE demonstration are provided in the docket for this rulemaking.

For the Greater Connecticut nonattainment area (including the two tribal territories) to have an attaining 2021-2023 DV for the 2015 ozone NAAQS, the EPA would have had to concur on all of the requested air quality monitoring data for exclusion in the EE demonstration that CT DEEP submitted for 2023. Furthermore, to qualify for an extension of the attainment date, the EPA would have to concur on all of the air quality monitoring data requested for exclusion at the Groton (New London County) monitoring site in the EE demonstration submitted for 2023. The EPA responded to CT DEEP's Initial Notification submittal for an intended EE demonstration, dated March 7, 2024, indicating that the events described may affect a future regulatory decision. 14 Because regulatory significance is required for EPA concurrence on an EE demonstration and subsequent exclusion of the event-influenced data from the design value, the EPA therefore determined it would evaluate the demonstration submitted by CT DEEP under the Exceptional Events Rule (EER). The demonstration submitted by CT DEEP stated that the exceedances measured on April 13-14 were caused by annual agricultural and prescribed fires from the Flint Hills region of Kansas, and nearby wildfires from Pennsylvania, New York, and New Jersey. The demonstration from CT DEEP also stated that there were exceedances or violations on June 30-July 1 due to Quebec, Canada, wildfires that transported smoke into the area. CT DEEP also asserted that high levels of ozone were recorded due to smoke from western Canadian wildfires on July 12. A summary of CT DEEP's exceptional event demonstration dates, type of events, and regulatory monitoring sites affected is outlined in Table 2 below.

The EPA concurred with CT DEEP's request to exclude data on June 30 and July 1, 2023, at the Groton monitoring site, and on July 1, 2023, at the East Hartford and Cornwall monitoring sites. However, the EPA did not concur with CT DEEP's request to exclude data on April 13-14 or July 12 from the Groton monitoring site. Please refer to the technical support document for EPA's July 22, 2024, EE decision located in the docket of this rulemaking for further information regarding EPA's decision on CT DEEP's EE demonstration.

The 2007 EER and 2016 EER  15 contain the procedural requirements and the criteria that the EPA uses to evaluate EE demonstrations. The demonstration must satisfy all of the EER criteria for the EPA to concur with excluding the air quality data from regulatory decisions. If any one of the criteria are not met, the EPA will nonconcur with the demonstration. In addition to the procedural requirements, the demonstration must include: (1) a narrative conceptual model describing the event(s) causing the exceedance or violation and a discussion of how the emissions from the event(s) led to the exceedance or violation, (2) a demonstration of a clear causal relationship between the event and the monitored exceedance or violation, (3) analyses comparing the event-influenced concentration to concentrations at the same monitoring site at other times to support the clear causal relationship, (4) a demonstration that the event was both not reasonably controllable and not reasonably preventable, and (5) a demonstration that the event was a human activity unlikely to recur at a particular location or was a natural event.

The EPA found that CT DEEP's demonstration met the Exceptional Events Rule criteria for some of the dates and monitors as noted above and determined that wildfire smoke events had regulatory significance for purposes of calculating the Area's most recent design value. As such, the EPA is proposing and taking comment on the EPA's July 22, 2024, decision regarding CT DEEP's request to exclude air quality monitoring data as an exceptional event for regulatory purposes. The rationale for the EPA's July 22, 2024, exceptional events determination is detailed in the docket. For this proposed action, the EPA will rely on the calculated design values that exclude the event-influenced data for the purpose of determining attainment of the 2015 ozone NAAQS. Further details on CT DEEP's analyses and the EPA's concurrence and nonconcurrence, including the exceptional events initial notification, exceptional events demonstration, the EPA's response to the initial notification, and EPA's technical support document can be found in the docket for this rulemaking.

While the EPA has concurred with CT DEEP's request to exclude event-influenced air quality monitoring data (June 30 and July 1, 2023, at the Groton monitoring site, and on July 1, 2023, at the East Hartford and Cornwall monitoring sites) from regulatory decisions, these regulatory actions require the EPA to provide an opportunity for public comment on the claimed exceptional events and all supporting data. This proposed action provides the public with an opportunity to comment on the claimed exceptional events, all supporting documents, and the EPA's concurrence and nonconcurrence with CT DEEP's request.

The EPA is proposing to determine that the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe portions of the Greater Connecticut area failed to attain the 2015 ozone NAAQS by the attainment date of August 3, 2024. Table 1 shows the annual fourth highest daily maximum 8-hour average ozone concentration and 2021-2023 DV for each monitor in the Greater Connecticut nonattainment area, which includes the two Tribes' territories.

The tribal portions of the Greater Connecticut area will be reclassified to Serious, the next higher classification, as provided under CAA section 181(b)(2)(A)(i) and codified at 40 CFR 51.1303. The areas are required to attain the standard “as expeditiously as practicable” but no later than 9 years after the initial designation as nonattainment, which in this case would be no later than August 3, 2027.

Moderate nonattainment areas that failed to attain the 2015 ozone NAAQS by the attainment date will be reclassified as Serious by operation of law upon the effective date of the final reclassification notice. EPA has addressed the Serious area requirements and SIP submittal schedule for relevant air agencies newly reclassified Serious areas, as well as the continued applicability of Moderate area requirements that these areas may not yet have met, in a separate rulemaking. 16 As discussed previously, under the CAA and TAR, Tribes may, but are not required to, submit implementation plans to the EPA for approval.

EPA is proposing that the tribal portions of the Greater Connecticut area failed to attain the 2015 ozone standard by the Moderate area attainment date of August 3, 2024, based on a 2021-2023 DV of 0.072 ppm. CAA section 181(b)(2) requires areas that have failed to attain by their attainment date be reclassified to the higher of (i) the next highest classification, or (ii) the classification that corresponds with the area's DV as of the time that the EPA publishes the document identifying the areas that have failed to attain by their attainment date. Accordingly, the EPA is proposing that the tribal portions of the area, which includes the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe, failed to attain the 2015 ozone NAAQS by August 3, 2024, and therefore the tribal portions of the nonattainment area must be reclassified as Serious.

As noted previously, a Tribe that is part of an area that is reclassified from Moderate to Serious nonattainment is not required to submit a TIP revision to address new Serious area requirements. Under the EPA requirements, the NNSR major source threshold and offset requirements change for stationary sources seeking preconstruction permits in any nonattainment areas newly classified as Serious, including on tribal lands. Areas such as the Mashantucket Pequot Tribal Nation and the Mohegan Indian Tribe that were already classified as Serious for a previous ozone NAAQS, however, are already subject to these lower thresholds and higher offset ratios, so a reclassification to Serious for the 2015 ozone NAAQS would have no effect on the NNSR permitting requirements for the tribal lands in those areas. 17 The EPA is soliciting public comment on the reclassification from Moderate to Serious nonattainment for the 2015 ozone NAAQS.

The EPA is also soliciting public comment on EPA's July 22, 2024, decision of CT DEEP's exceptional events demonstration to exclude air quality data from the 2023 ozone season and its decision to nonconcur on other elements of CT's demonstration. This is in accordance with EPA's 2016 Exceptional Events Rule (EER). 18 The EPA is taking comment for 30 days upon publication of this proposed rule in the Federal Register . Interested parties may participate in the Federal rulemaking procedure by submitting written comments to this proposed rule by following the instructions listed in the ADDRESSES section of this Federal Register .

This action is not a “significant regulatory action” under the terms of Executive Order 12866 (58 FR 51735, October 4, 1993) and is therefore not subject to review under Executive Order 14094 (88 FR 21879, April 11, 2023).

This action is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because determinations of attainment by the attainment date under the CAA are exempt from review under Executive Order 12866.

This rule does not impose an information collection burden under the provisions of the PRA of 1995 (44 U.S.C. 3501 et seq. ). This action does not contain any information collection activities and serves only to propose determinations that the tribal portions of the Greater Connecticut nonattainment area failed to attain the 2015 ozone standards by the August 3, 2024, attainment date where such areas will be reclassified as Serious nonattainment for the 2015 ozone standards.

This action is certified as not having a significant economic impact on a substantial number of small entities under the RFA (5 U.S.C. 601 et seq. ). This action will not impose any requirements on small entities. The determination of failure to attain the 2015 ozone standards (and resulting reclassifications), do not in and of themselves create any new requirements beyond what is mandated by the CAA.

This action does not contain any unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538 and does not significantly or uniquely affect small governments. The action imposes no enforceable duty on any state, local or tribal governments or the private sector.

This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government. The division of responsibility between the Federal government and the states for purposes of implementing the NAAQS is established under the CAA.

Executive Order 13175 (65 FR 67249, November 9, 2000), requires EPA to develop an accountable process to ensure “meaningful and timely input by Tribal officials in the development of regulatory policies that have Tribal implications.” This action has Tribal implications. However, it will neither impose substantial direct compliance costs on federally recognized tribal governments, nor preempt tribal law. As noted previously, a Tribe that is part of an area that is reclassified from Moderate to Serious nonattainment is not required to submit a TIP revision to address new Serious area requirements. However, the EPA is proposing the determinations of failure to attain in this action. Ordinarily, the NNSR major source threshold and offset requirements will change for stationary sources seeking preconstruction permits in any nonattainment areas newly classified as Serious, including on tribal lands. Areas that are already classified as Serious for a previous ozone NAAQS, however, are already subject to these higher offset ratios and lower thresholds, so a reclassification to Serious for the 2015 ozone NAAQS would have no effect on the NNSR permitting requirements for the tribal lands in those areas.

The EPA has communicated with the affected Tribes located within the boundaries of the nonattainment area addressed in this proposed rule to inform them of this forthcoming action.

EPA interprets Executive Order 13045 (62 FR 19885, April 23, 1997) as applying to those regulatory actions that concern environmental health or safety risks that EPA has reason to believe may disproportionately affect children, per the definition of “covered regulatory action” in section 2-202 of the Executive Order. This action is not subject to Executive Order 13045 because it does not establish an environmental standard intended to mitigate health or safety risks.

This action is not subject to Executive Order 13211 (66 FR 28355, May 22, 2001) because it is not a significant regulatory action under Executive Order 12866.

This rulemaking does not involve technical standards. Therefore, EPA is not considering the use of any voluntary consensus standards.

Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA.

This proposed SIP revision affects the Metro Plant at 2400 Childs Road, Saint Paul, Minnesota. This facility utilizes three fluidized bed incinerators each using activated carbon, a baghouse, a wet scrubber, and a wet electrostatic precipitator to process wastewater solids and reduce PM 10 emissions. The facility's permit contains site-specific restrictions as part of Minnesota's SIP for PM 10 in the Red Rock Road PM 10 Maintenance Area. This SIP currently contains non-expiring title I conditions from a part 70 permit issued for the facility (Permit No. 12300053-006), which establish emission limits and various conditions that were deemed essential to reach attainment for the 1987 National Ambient Air Quality Standards (NAAQS) for PM 10 . This amendment to the MCES permit allows for the addition of a new emission unit, specifically an additional fluidized bed incinerator. To ensure the addition of this new unit will not cause a violation of the PM 10 standard, an emission limit decrease and discontinuation of some emission units are being included in the permit revision. This permit revision results in a reduction of allowable PM 10 emissions at the facility; therefore, the MPCA is requesting that EPA approve changes to the site-specific SIP for MCES (included in the Minnesota SIP at 40 CFR 52.1220).

The purpose of Minnesota's permit action and related site-specific SIP revision is to address changes at the facility, specifically the addition of a fluidized bed incinerator, and decreases in other emission limits, many of which are affected by title I SIP conditions. This SIP revision is being proposed with an amendment to a part 70 permit maintaining federally enforceable title I SIP conditions (Air Emission Permit No. 12300053-102). The permit is final and was published on January 4, 2024, with an administrative amendment on March 6, 2024. MPCA provided EPA with detailed emissions information for each of the changes to the permit and SIP as well as the overall PM 10 emission changes from the prior SIP submittal that EPA approved on September 11, 2002 (67 FR 57517), (associated with permit 12300053-006), to this submittal (associated with permit 12300053-102). This SIP revision incorporates several changes made in Permit No. 12300053-102 including lower allowable PM 10 emissions at the facility through more stringent emissions limits on several pieces of equipment and processes. The limits for existing fluidized bed incinerators (FBIs) EQUI 3, EQUI 4, and EQUI 5 will be lowered from 2.01 pounds per hour (lbs/hr) PM 10 to 1.70 lbs/hr PM 10 on a 3-run average, as specified in permit conditions 5.7.13, 5.8.13, and 5.9.13. The limits for auxiliary boilers EQUI 10 and EQUI 11 will be lowered from 25.82 pounds per day (lbs/day) PM 10 to 18.54 lbs/day PM 10 on a 24-hour block average, as specified in permit condition 5.3.13. The limit for ash loadout housekeeping vacuum EQUI 50 will be lowered from 0.05 grains per dry standard cubic foot (gr/dscf) PM 10 to 0.005 gr/dscf PM 10 , on a 3-run average, as specified in permit condition 5.24.2. Finally, MCES will also use natural gas instead of fuel oil in EQUI 10 and EQUI 11 significantly lowering the PTE from 1.23 lbs/hr PM 10 to 0.39 lbs/hr PM 10 and will modify their ash handling equipment to meet the new proposed PM 10 emission limit of 0.005 gr/dscf. The facility modeled these lower PM 10 emissions limits in conjunction with equipment and operational limitations and the analysis showed a combined decrease of 6.3 tons per year in allowable emissions from the actions proposed in the title I SIP revision. The changes meet section 110(l) requirements since they are all decreases in emissions.

The permit also includes changes that will not be incorporated into the SIP but are included in the docket as part of the submittal. These changes are still federally enforceable through non-expiring title I NAAQS synthetic minor conditions included in the facility's permit, under Minnesota's EPA-approved permit program. Specifically, these permit revisions include plans to build a fourth FBI (EQUI 133) and additional revisions such as rerouting of the pressure relief cycles. The potential to emit (PTE) from adding EQUI 133 and discontinuing EQUI 9 will be lowered from 14.08 lbs/hr to 9.22 lbs/hr. If MCES builds EQUI 133, it must also forfeit the construction and operation of three alkaline stabilization cells (EQUI 6, EQUI 7, EQUI 8). If MCES is unable to build the fourth FBI, MCES may continue with the previously permitted and SIP-approved construction and operation of three alkaline stabilization cells (EQUI 6, EQUI 7, EQUI 8). The facility provided modeling to demonstrate that these changes do not contribute to exceedances or violations of the PM 10 standard which were assessed through the New Source Review program to ensure they meet Clean Air Act (CAA) requirements.

Under section 110(l) of the CAA, EPA cannot approve a SIP revision if it would interfere with attainment of the NAAQS, reasonable further progress toward attainment, or any other applicable requirement of the CAA. Through this submittal, MPCA has demonstrated to EPA that 110(l) requirements have been met through the permit amendment and the successive SIP revision. The SIP revision shows a decrease in emissions and the permit changes have also been demonstrated to not interfere with attainment of the NAAQS. Therefore, EPA finds that Minnesota's permit action and successive SIP revision meet CAA requirements.

EPA is proposing to incorporate into Minnesota's SIP all the conditions cited as “Title I Condition: 40 CFR 52.1220 (PM 10 SIP)” in Permit No. 12300053-102. These revisions include both the changes in ash handling within the facility and the lower allowable PM 10 emissions for each Fluidized Bed Incinerator (EQUI 3, EQUI 4, EQUI 5), auxiliary boilers (EQUI 10, EQUI 11), and ash loadout vacuum (EQUI 50).

This SIP submittal includes Permit No. 12300053-102 and the supporting technical documentation.

In this rulemaking, EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, EPA is proposing to incorporate by reference all the conditions cited as “Title I Condition: 40 CFR 52.1220(PM 10 SIP)” in Minnesota Permit No. 12300053-102, published on January 4, 2024, with an administrative amendment on March 6, 2024, discussed in section II of this preamble. EPA has made, and will continue to make, these documents generally available through www.regulations.gov and at the EPA Region 5 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, EPA's role is to approve State choices, provided that they meet the criteria of the CAA. Accordingly, this action merely approves State law as meeting Federal requirements and does not impose additional requirements beyond those imposed by State law. For that reason, this action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);

• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866;

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. );

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. );

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);

• Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);

• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a State program;

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and

• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the rulemaking 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).

On August 11, 2023, the Department of Energy and Environment (DOEE) submitted a revision to the DC SIP to create a synthetic minor permit program and address regulatory differences between the District's current regulations and those approved previously in Chapters 1 and 2 of the Air Quality Regulations. DOEE submitted the SIP revision request along with a SIP revision related to Startup, Shutdown, and Malfunction (SSM). Those proposed SIP Revisions related to Chapter 1 and SSM will be processed in a separate SIP action.

A SIP-approved minor source permitting program can include provisions for issuing permits that establish federally enforceable emissions limits to restrict the Potential to Emit (PTE) of certain pollutants below major stationary source and major modification applicability thresholds. “Synthetic minor” permits establish these federally enforceable emission limits for sources obtaining construction permits, and also establish these emission limits in the corresponding operating permits.

This DC SIP revision is intended to create a synthetic minor permit program through provisions in title 20 of the District of Columbia Municipal Regulations (20 DCMR), specifically 20 DCMR Chapter 2 Section 200.6 and 200.7 as amended, in conjunction with other provisions that already existed in 20 DCMR Chapter 2 and were previously approved into the DC SIP. These provisions enable a new source or modification of an existing source to limit its PTE below major source thresholds in order to qualify as minor and avoid major new source review (NSR) applicability, including the prevention of significant deterioration (PSD) in attainment areas and nonattainment NSR (NNSR) in nonattainment areas. These provisions also allow new sources or modifications of existing sources to avoid major source status under title V of the CAA through limiting PTE. A stationary source may request federally enforceable permit limits to limit its PTE to below major source threshold, thus becoming a minor source “synthetically.” The intended effect is similar to federally enforceable state operating permit (FESOP) programs established in many states. State operating permit programs which have been incorporated into the SIP render operating permits issued pursuant to such a program federally enforceable. This FESOP mechanism allows sources to reduce their PTE to below the title V applicability thresholds and thereby legally avoid being subject to title V.

On June 28, 1989 (54 FR 27274), the EPA published criteria for approving and incorporating into the SIP regulatory programs for the issuance of federally enforceable state operating permits (“June 28, 1989 Final Rule”). 1 Permits issued pursuant to an operating permit program meeting these criteria and approved into the SIP are considered federally enforceable. The EPA has encouraged States to consider developing such programs in conjunction with title V operating permit programs for the purpose of creating federally enforceable limits on a source's PTE. The EPA published a guidance document on September 18, 1992 entitled “Limitation of Potential to Emit with Respect to Title V Applicability Thresholds” to address a state's ability to utilize a title V permit, or other federally-enforceable means, to limit the PTE for various purposes. 2 On January 22, 1996, the EPA released the Seitz memo “EPA Interim Policy on Federal Enforceability Requirement for Limitations on Potential to Emit.” 3 This mechanism would enable sources to reduce their PTE of criteria pollutants to below the title V applicability thresholds and avoid being subject to title V.

The purpose of DC's synthetic minor program is to provide sources a mechanism to avoid Title V and new source review major source applicability and make those synthetic minor permit conditions both enforceable by the District and federally enforceable. Therefore, requirements for the development of a FESOP program are appropriate criteria with which to evaluate the DOEE synthetic minor program.

The District of Columbia submitted a SIP revision to create a synthetic minor permitting program. The revisions are also intended to address regulatory differences between the District's current regulations and those regulations approved previously, thus clarifying and resolving errors in the existing regulations.

Section 200 (General Permit Requirements) of 20 DCMR Chapter 2 (General and Non-attainment Area Permits) establishes synthetic minor program provisions. Section 200.6 allows the Department to establish a condition in a permit issued pursuant to this chapter that limits, in a manner that is enforceable as a practical matter, emissions from a source so as to avoid applicability of the permitting requirements of 20 DCMR Section 300.1 ( i.e., DC's title V regulations). Essentially, this provision creates a synthetic minor operating permit program, along with other provisions in 20 DCMR Chapter 2. Section 200.7 allows the Department to establish a condition in a permit issued pursuant to this chapter that limits, in a manner that is enforceable as a practical matter, emissions from a source so as to avoid applicability of a District or Federal air quality regulation, other than the requirements of 20 DCMR section 300.1, except when prohibited by another District or Federal regulation. Essentially, the provision creates a synthetic minor preconstruction permit program. Through provisions in sections 200.6, 200.7 and other sections in 20 DCMR Chapter 2, DOEE establishes a synthetic minor program to issue synthetic minor operating permits and synthetic minor preconstruction permits in DC.

Other substantive changes in Chapter 2 include revisions in the following sections: (1) in 20 DCMR section 200.8 establishes a source category permit covering a group of similar sources or emission units; (2) in 20 DCMR sections 200.9, 200.10, 200.11, 200.12, 200.13, 200.14, and 200.15 cover administrative aspects of permits issued in Chapter 2 including applications, data requirements, fees, signature process, exceptions and compliance; (3) in 20 DCMR section 202, Amendment, Suspensions, Revocation, and Denial of Permits, revisions in sections 202.1, 202.2, 202.6, 202.7, and 202.8 are related to requirements and procedures on amendment, suspension, revocation, and denial of permits; and, 4) in 20 DCMR section 210, Notice and Comment Prior to Permit Issuance, revisions in sections 210.3, 210.4, 210.5, and 210.6 are related to requirements and procedures on public notice and comment prior to permit issuance.

In the June 28, 1989 Final Rule, the EPA amended the definition of “federally enforceable” to clarify that terms and conditions contained in state-issued operating permits are federally enforceable for purposes of limiting a source's maximum potential emission rates or PTE. The June 28, 1989 Final Rule also established five criteria for the EPA to approve a state operating permit program. The following describes each of the criteria for approval of a state operating permit program for the issuance of federally enforceable operating permits for purposes of limiting a source's PTE and how DOEE's SIP submittal seeking to establish a synthetic minor program satisfies those criteria.

(1) The State operating permit program ( i.e., the regulations or other administrative framework describing how such permits are issued) is submitted to and approved by the EPA into the SIP.

On August 11, 2023 DOEE submitted a SIP revision request for approval of its synthetic minor permit program. The DC permit program codified in 20 DMCR Chapter 2 provides the framework for general and non-attainment area permits issuance. DC revised 20 DCMR Chapter section 200.6 to establish conditions for a source to avoid title V permit requirements, and section 200.7 to establish conditions to avoid major NSR requirements and applicability of other major source requirements. DC has requested these revisions to be approved into the DC SIP.

(2) The SIP imposes a legal obligation that operating permit holders adhere to the terms and limitations of such permits (or subsequent revisions of the permit made in accordance with the approved operating permit program) and provides that permits which do not conform to the operating permit program requirements and the requirements of the EPA's underlying regulations may be deemed not “federally enforceable” by the EPA.

The DOEE permit program in 20 DCMR Chapter 2 section 200.15 explicitly requires that a person shall comply with the conditions of any permit issued pursuant to this chapter. The general provisions of the permit program at sections 200.6 and 200.7 establish that permit conditions must be enforceable as a practical matter. Furthermore, the permit program's definitions of “enforceable as a practical matter” and “federally enforceable” in 20 DCMR Chapter 1 section 199 require that permit terms must meet the EPA's minimum criteria for Federal enforceability, including public participation and practical enforceability requirements.

(3) The State operating permit program requires that all emissions limitations, controls, and other requirements imposed by such permits be at least as stringent as any other applicable limitations and requirements contained in the SIP or enforceable under the SIP. The State operating permit program also requires that the program not issue permits that waive, or make less stringent, any limitations or requirements contained in or issued pursuant to the SIP, or that are otherwise “federally enforceable” ( e.g. standards established under sections 111 and 112 of The Act).

The DC synthetic minor program established in section 200.6 and 200.7, requires that all limits in permits issued pursuant to this Chapter shall be enforceable as a practical matter, and limits must not be designated as enforceable only by the District, i.e., federally enforceable. Permits shall contain emission limitations and other requirements that are at least as stringent as any applicable limitation in the SIP. The program also establishes that no permit shall contravene the requirements of any other District or Federal regulations.

(4) The limitations, controls, and requirements in the operating permits are permanent, quantifiable, and otherwise enforceable as a practical matter.

Sections 200.6 and 200.7 state that a permit condition must be “enforceable as a practical matter.” DC regulations in 20 DMCR section 199 define “federally enforceable” and “enforceable as a practical matter”. The definition of “Federally enforceable” in section 199 matches verbatim the definition in 40 Code of Federal Regulations (CFR) 51.165. The DOEE permit program defines “enforceable as a practical matter” to mean that a permit must specify emission limitation or standards the source subject to, the time period for the limitation, and the method to determine compliance (See 20 DCMR section 199). Sufficient recordkeeping, reporting, and monitoring provisions must also be provided to ensure compliance.

(5) The permits are issued subject to public participation. This means that the State agrees, as part of its program, to provide the EPA and the public with timely notice of the proposal and issuance of such permits, and to provide the EPA, on a timely basis, with a copy of each proposed (or draft) and final permit intended to be federally enforceable. This process must also provide an opportunity for public comment on the permit applications prior to issuance of the final permit (54 FR 27274, June 28, 1989).

The “federally enforceable” synthetic minor permits issued under the permit program are subject to public participation. The permit program's public participation provisions at 20 DMCR Chapter 2 section 210 require that for a permit to be federally enforceable the draft permit must be subject to an adequately publicized 30-day public comment period. The permit program also provides the opportunity for a public hearing. The general provisions of the permit program at section 210.6 require DOEE to provide the EPA with a copy of the draft permit and final permit on a timely basis.

Therefore, DC's synthetic minor program is consistent with the five criteria for approving a state operating permit program into a SIP. Permits issued under an approved program are federally enforceable and may be used to limit the PTE for sources of criteria air pollutants. In meeting those five requirements as discussed above, DC's synthetic minor program also meet the requirements of 40 CFR 51.160 through 165 on legally enforceable procedures, public availability of information, administrative procedure and permit requirements.

Section 110(a)(2)(C) of the CAA requires that SIPs include a program to regulate the construction and modification of stationary sources as necessary to ensure that the national ambient air quality standards (NAAQS) are maintained. 20 DMCR Chapter 2 section 200 and section 204 have been part of the DC SIP for many years and meet the requirements in section 110(a)(2)(C) of the Act which requires all SIPs to provide for the regulation of the modification and construction of any stationary source within the areas covered by the plan implementation as necessary to assure that NAAQS are achieved. CAA section 110(l) provides that revision to an implementation plan submitted by a state under this chapter shall be adopted by such state after reasonable notice and public hearing. The DC SIP submission provided documentation of public comment and public hearing notices of the DC rulemaking. The DC SIP submission met the public notice and public hearing requirements. Further, because the permits issued under DC's synthetic minor permit program will be federally enforceable, and the limitations, controls and requirements in the permits will be permanent, quantifiable and enforceable as a practical matter, the EPA finds that these revisions in DC SIP will not interfere with any applicable requirement concerning attainment and reasonable further progress, or any other applicable CAA requirement. Therefore, the proposed DC SIP revision meets the requirements of 110 of the CAA.

The EPA has reviewed DC's proposed changes to the DOEE's permit program in 20 DCMR Chapter 2 and has determined that they meet all applicable Federal requirements for approval. The EPA proposes to approve the District of Columbia's August 11, 2023 SIP revision for creating a synthetic minor permit program, pursuant to section 110 of the CAA and the approval criteria specified in the June 28, 1989 Federal Register document (54 FR 27274-27286).

The EPA is soliciting public comments on the issues discussed in this document. These comments will be considered before taking final action.

In this document, the EPA proposes to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA proposes to incorporate by reference the DC air quality regulations in Chapter 2 of 20 DCMR, as describe in section II of this document. The EPA has made, and will continue to make, these materials generally available through www.regulations.gov and at the EPA Region III Office (please contact the person identified in the For Further Information Contact section of this preamble for more information).

Under the Clean Air Act, the Administrator is required to approve a SIP submission that complies with the provisions of the Clean Air Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the Clean Air Act. Accordingly, this action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by State law. For that reason, this action:

• 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);

• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866:

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. );

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. );

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);

• Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);

• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and

• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where the EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the rule does not have Tribal implications and will not impose substantial direct costs on Tribal governments or preempt Tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

Throughout this document, the use of “we” and “our” means “the EPA.”

On October 30, 2025 (90 FR 48855), we published “Air Plan Approval; AK; Regional Haze Plan for the Second Implementation Period” in the Federal Register . In that proposed rulemaking we proposed to approve the Alaska regional haze plan for the second implementation period and opened a 30-day comment period, ending on December 1, 2025. We received a request from the public to extend the comment period an additional 15 days, to allow interested persons additional time to prepare and submit comments. We are granting the request. Written comments must now be received on or before December 16, 2025.

For additional information on regulatory background and the EPA's technical findings relating to the Facility RACT, the reader can refer to the Technical Support Document (TSD) that is contained in the EPA docket assigned to this Federal Register document.

Ground level ozone is a secondary air pollutant that is created by the chemical reactions that occur when ozone precursors, including nitrogen oxides (NO X ) and volatile organic compounds (VOC), chemically react in the presence of sunlight. 1 Emissions from industrial facilities are anthropogenic sources of ozone precursors. The EPA regulates criteria pollutants, such as ozone, by establishing NAAQS. With respect to this proposed action, there are two relevant ozone NAAQS. First, on March 12, 2008, the EPA promulgated a revision to the ozone NAAQS, setting both the primary and secondary standards at 0.075 parts per million (ppm), averaged over an 8-hour time frame (“The 2008 8-hour Ozone Standard”). See 73 FR 16436 (March 27, 2008). Second, on October 1, 2015, the EPA lowered these standards to 0.070 ppm, averaged over an 8-hour time frame (“The 2015 8-hour Ozone Standard”). See 80 FR 65292 (October 26, 2015).

The State of New York has two ozone nonattainment areas. 2 CAA section 182 requires states with ozone NAAs to include in their SIPs, among other things, provisions to require the implementation of RACT. In addition, under CAA section 184, the State of New York is located within the Ozone Transport Region (OTR), which means that all major sources of VOC and NOx within the State are subject to statewide RACT requirements. RACT is defined as the lowest emission limit that a source is capable of meeting through the application of control technology that is reasonably available considering technological and economic feasibility. 3

CAA section 184(b)(2) and 182(f)(1) set forth the requirements to establish control measures to implement RACT for major sources of VOC and/or NO X located in the OTR. RACT for a particular source is determined on a case-by-case basis, considering the technological and economic circumstances of the individual source. The New York State Department of Environmental Conservation (NYSDEC) RACT regulations require applicable facilities to meet certain requirements, referred to as “presumptive RACT requirements.” These presumptive requirements generally require sources to implement emission limits, control efficiency requirements, specific control technologies, averaging plans, and/or fuel/raw material switching practices.

Under existing NYSDEC RACT regulations, facilities are required to assess all technologically feasible control options that meet the State's cost threshold. The cost threshold for NYSDEC RACT requirements is found under NYSDEC 2013 policy, “DAR-20 Economic and Technical Analysis for Reasonably Available Control Technology (RACT).” Under this policy, facilities must consider in their RACT determinations control technologies that remove VOC or NO X emissions up to a certain cost threshold, expressed in a dollar amount per ton of VOC or NO X removed, which includes an inflation-adjusted economic threshold. 4

In some instances, the presumptive RACT requirements may not be technologically or economically feasible for a certain source, and the State can make a source-specific RACT determination, which is submitted to the EPA as a SSSIP. A SSSIP should include a facility's RACT plan that demonstrates how a facility will implement RACT; as well as the applicable CAA Title V operating permit conditions that address RACT requirements. Upon the EPA's final approval of a SSSIP, the relevant RACT permit conditions for a Facility become part of the Federally enforceable SIP.

This action relates to a SSSIP revision that concerns Athens Generating Plant (“Athens” or “the Facility”), which is combined-cycle power plant that generates 1,080 megawatts (MW) of electricity for sale to New York State's electricity grid system. The sources at issue in this action are the Facility's three combined-cycle Westinghouse 501G combustion turbines, each with a base load of 245 MW, with associated heat recovery steam generators (HRSGs) and steam turbines, each with a base load of 115MW used to generate electricity (Emission Units U-00001, U-00002, and U-00003).

Emission Units U-00001, U-00002, and U-00003 are characterized as combined-cycle combustion turbines with a maximum heat input rate of 10 million Btu per hour or greater, as specified under 6 NYCRR subpart 227-2, “Reasonably Available Control Technology (RACT) for Oxides of Nitrogen (NO X ).” Although combined-cycle combustion turbines produce NO X emissions while generating electricity, they are more efficient than simple-cycle turbines because they utilize both fuel and steam to power turbines. Specifically, they generate electricity by igniting a mixture of either natural gas or No. 2 distillate fuel oil (oil firing is limited to 1,080 hours annually per unit at Athens) with compressed air and using the resulting hot, expanding exhaust gases, to spin turbine blades that drive a generator to convert the spinning turbine energy into electricity. In addition, rather than allowing for exhaust gases that would have otherwise been released to the atmosphere, they are directed to a HSRG to produce steam, which then spins a steam turbine to generate additional electricity.

NYSDEC's RACT regulations establish RACT requirements for combustion turbines in 6 NYCRR subpart 227-2” last approved by the EPA, into the New York SIP, on July 12, 2013. See 78 FR 41846. Specifically, 6 NYCRR 227-2.4(e)(3) requires that the owner or operator of all combustion turbines operating after July 1, 2014, to submit a proposal for RACT to be implemented that includes descriptions of: (1) The available NO X control technologies, the projected effectiveness of the technologies considered, and the costs for installation and operation for each of the technologies; and (2) The technology and the appropriate emission limit selected as RACT considering the costs for installation and operation of the technology.

Because the NYSDEC's RACT regulations at 6 NYCRR 227-2.4(e)(3) require that a source-specific RACT proposal for combustion turbines operating after July 1, 2014, be submitted to the NYSDEC, such source-specific proposals must be submitted to the EPA as a SSSIP. This SSSIP was submitted by the NYSDEC on April 22, 2024, to satisfy such requirements. The EPA has reviewed the RACT determinations in the SSSIP submittal for Emission Units U-00001, U-00002, and U-00003 in a manner that is consistent with the CAA and the EPA's regulations, as interpreted through the EPA's actions and guidance.

As required by 6 NYCRR 227-2.4(e)(3), the Facility submitted a RACT plan, dated October 2020, detailing emission limit requirements for Emission Units U-00001, U-00002, and U-00003. The NYSDEC approved the specified emission limits as adequately implementing RACT for the applicable emission units and submitted them for the EPA's approval. Upon the EPA's final approval of this SSSIP, the RACT variance emission limits for the Facility will become part of the Federally enforceable SIP.

The Facility's RACT plan stated that the existing controls of using a Dry Low NO X (DLN) combustion system when firing natural gas, and water or steam injection when firing distillate fuel oil, both in combination with a Selective Catalytic Reduction (SCR) are consistent with the best available control technologies (BACT) and Lowest Achievable Emission Rate (LAER) requirements for NO X . Because BACT requirements are more stringent than the applicable NO X RACT requirements, 5 the NYSDEC determined that these emission units comply with the State's applicable NO X RACT requirements under 6 NYCRR part 227-2.4(e).

The NYSDEC reviewed the Facility's RACT plan and determined that the case-by-case emission limits implement RACT for Emission Units U-00001, U-00002, and U-00003. Specifically, the NYSDEC approved the following case-by-case emission limit: (1) The NO X emission limits for the applicable units, as listed under conditions #82 and #83 of the Title V permit, are restricted to 9.0 parts per million by volume (ppmv) corrected to 15% oxygen when firing fuel oil and 2.0 ppmv corrected to 15% oxygen when firing natural gas; (2) Dry Low NO X (DLN) combustion system, when firing natural gas, and water or steam injection, when firing distillate fuel oil, in combination with a Selective Catalytic Reduction (SCR) are considered BACT/LAER; (3) emissions are effectively monitored via Continuous Emissions Monitoring Systems (CEMS), reported on a semi-annual basis, and maintained for up to five years.

The intended effect of New York's SSSIP submission is to establish emission limits for Emission Units U-00001, U-00002, and U-00003. The EPA proposes to determine that the emission limits for Emission Units U-00001, U-00002, and U-00003 implement RACT because: (1) it was demonstrated that no additional control technologies beyond what are currently used at the Facility are technically and economically feasible; (2) the EPA's review of the RBLC indicated that the current existing controls are consistent with BACT/LAER requirements and more stringent than RACT requirements; (3) the provisions adequately restrict emissions of NO X and implement sufficient monitoring, reporting, and recordkeeping requirements.

In order to determine what NO X control technologies could be economically and technologically feasible for Emission Units U-00001, U-00002, and U-00003, the EPA reviewed the Reasonably Available Control Technology/Best Available Control Technology/Lowest Achievable Emission Rate Clearinghouse (RBLC). 6 The EPA's review of the RBLC consisted of searching for controls on existing large combined-cycle combustion turbines permitted in the ten years prior to the Facility's RACT plan. The RBLC confirmed that existing controls at the Facility are representative of BACT/LAER; therefore, these controls are also representative of RACT. In addition, the EPA's review of the RBLC revealed that no similar combined-cycle combustion turbine has NO X controls technologies that are economically feasible, aside from the controls that the Facility has already implemented. Further detail on the RBLC results is provided in the TSD that is available in the docket for this rulemaking.

The NO X RACT emission limits for Emission Units U-00001, U-00002, and U-00003 are specified in Conditions #38, 54, 62, 82, and 83 of the facility's Title V operating permit, which also include monitoring, reporting, and recordkeeping requirements. The state's submittal requests that these portions of the Title V permit be incorporated into the SIP. With this rulemaking, the EPA is proposing to determine that the emission limits for the units, as submitted by the NYSDEC with this SSSIP submittal, represent the lowest limits achievable with reasonably available control technologies, considering technological and economic feasibility. Further detail on the EPA's analysis is provided in the TSD available in the docket for this rulemaking.

The EPA is proposing to approve this current Source-specific SIP revision because the emission limits included in the SSSIP are demonstrated to implement RACT for Emission Units U-00001, U-00002, and U-00003, that represent three combined-cycle combustion turbines with associated HRSGs and steam turbines. Based on information provided by the NYSDEC in its April 22, 2024 submission, the EPA's review of the RBLC for similar sources and facilities, and an analysis of this SSSIP revision, the EPA proposes to approve the NO X emission limits for Emission Units U-00001, U-00002, and U-00003 located at Athens Generating Plant.

Specifically, the EPA proposes to approve the following limits and associated requirements as implementing RACT: The Facility must: (1) continue to implement the current combined-cycle combustion turbine NO X emission controls of SCR and Dry Low NO X burners for natural gas and SCR and water injection for distillate fuel oil (Condition #38); (2) control emission of NO X to less than 23.4 lbs/hour when firing natural gas and 101.9 lbs/hour when firing fuel oil, as averaged over a 3-hour block via CEMS and reported on a semi-annual basis (Conditions #54 and 62); and (3) limit NO X emissions to 9.0 ppmv corrected to 15% oxygen when firing fuel oil and 2.0 ppmv corrected to 15% oxygen when firing natural gas, as averaged over a 3-hour block via CEMS and reported on a semi-annual basis (Conditions #82 and 83).

In this document, the EPA is proposing to include regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference revisions to Athens Generating Plant's Title V operating permit conditions #38, 54, 62, 82, and 83 as described in section II and III of this preamble. The EPA has made, and will continue to make, these materials generally available through www.regulations.gov.

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the Clean Air Act 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 Clean Air Act. Accordingly, this action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Order 12866 (58 FR 51735, October 4, 1993);

• Is not subject to Executive Order 14192 (90 FR 9065, February 6, 2025) because SIP actions are exempt from review under Executive Order 12866:

• Does not impose an information collection burden under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq. );

• Is certified as not having a significant economic impact on a substantial number of small entities under the Regulatory Flexibility Act (5 U.S.C. 601 et seq. );

• Does not contain any unfunded mandate or significantly or uniquely affect small governments, as described in the Unfunded Mandates Reform Act of 1995 (Pub. L. 104-4);

• Does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999);

• Is not subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and

• Is not subject to requirements of section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the Clean Air Act.

In addition, the SIP is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian Tribe has demonstrated that a Tribe has jurisdiction. In those areas of Indian country, the rule does not have Tribal implications and will not impose substantial direct costs on Tribal governments or preempt Tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

In the Final Rules section of this Federal Register , EPA is approving the State's SIP submittal as a direct final rule without prior proposal because the Agency views this as a noncontroversial submittal and anticipates no adverse comments. A detailed rationale for the approval is set forth in the direct final rule. If no relevant adverse comments are received in response to this rule, no further activity is contemplated. If EPA receives such comments, the direct final rule will be withdrawn and all public comments received will be addressed in a subsequent final rule based on this proposed rule. EPA will not institute a second comment period. Any parties interested in commenting on this action should do so at this time. Please note that if EPA receives adverse comment on an amendment, paragraph, or section of this rule and if that provision may be severed from the remainder of the rule, EPA may adopt as final those provisions of the rule that are not the subject of an adverse comment. For additional information, see the direct final rule which is located in the Rules section of this Federal Register .

The CAA requires state regulatory agencies to implement emission guidelines and associated compliance times using a state plan developed under sections 111(d) and 129 of the CAA. Section 111(d) of the CAA establishes standards of performance for certain existing sources. Air pollutants included under this section are those which have not already been established as air quality criteria pollutants via 42 U.S.C. 7408(a) or hazardous air pollutants via 42 U.S.C. 7412. Section 111(d)(1) requires states to submit to EPA for approval a plan that establishes standards of performance. The plan must provide that the state will implement and enforce the standards of performance.

Section 129 of the CAA requires emission guidelines to be promulgated for solid waste incineration units, including LMWCs. Section 129 mandates that all plan requirements be at least as protective as the promulgated emission guidelines, including fixed final compliance dates, fixed compliance schedules, and title V permitting requirements for all affected sources. Section 129 also requires the states to submit plans to the EPA within one year after promulgation of the emission guidelines and compliance times.

The EPA prescribes a Federal plan if a state does not submit a state-specific plan or the submitted plan is disapproved. If a state has no designated facilities for a standards of performance source category, it may submit a negative declaration in lieu of a state plan for that source category in accordance with 40 Code of Federal Regulations (CFR) 60.23(b), 60.23a(b) and 62.06.

The Emissions Guidelines and Compliance Times for Large Municipal Waste Combustors That are Constructed on or Before September 20, 1994, as codified at 40 CFR part 60 subpart Cb (subpart Cb) apply to states with designated LMWCs. An LMWC is defined at 40 CFR 60.32b(a). The designated facilities to which the emission guidelines and compliance times apply are existing LMWC units for which construction was commenced on or before September 20, 1994.

The Emissions Guidelines for Greenhouse Gas Emissions From Existing Crude Oil and Natural Gas Facilities, as codified at 40 CFR part 60 subpart OOOOc (subpart OOOOc) apply to states with one or more of the onshore designated facilities listed under 40 CFR 60.5386c(a) through (h) for which construction, modification, or reconstruction was commenced on or before December 6, 2022. The crude oil and natural gas source category is defined at 40 CFR 60.5430c.

The Emission Guidelines for Greenhouse Gas Emissions for Electric Utility Generating Units, as codified at 40 CFR part 60 subpart UUUUb (subpart UUUUb) apply to states with an affected steam generating unit (EGU) as defined at 40 CFR 60.5845b(b). EGUs addressed by this subpart include those specified by the dates listed under 40 CFR 60.5845(a).

The DCDOEE submitted negative declarations to the EPA on July 19, 2024, and August 28, 2024, certifying that there are no existing large municipal waste combustors, crude oil and natural gas facilities, or electric utility generating units in its jurisdiction that are subject to the requirements of 40 CFR part 60 subpart Cb, subpart OOOOc, and subpart UUUUb, respectively. For additional background information on DCDOEE's negative declaration, see the documents that are available at Regulations.gov, Docket ID No. EPA-R03-OAR-2025-1746.

The EPA is proposing to amend 40 CFR part 62 to reflect EPA's receipt of DCDOEE's negative declarations for large municipal waste combustors, crude oil and natural gas facilities, and electric utility generating units. The negative declarations satisfy the requirements of 40 CFR 60.23(b), 60.23a(b), and 62.06, serving in lieu of a CAA section 111(d)/129 plan for existing large municipal waste combustors, crude oil and natural gas facilities. The EPA is soliciting public comments on the issues discussed in this document. These comments will be considered before taking final action.

Under the CAA, the EPA has the authority to delegate to a state or local agency the authority to implement a 111(d)/129 Federal Plan so long as the delegation complies with the provisions of the CAA and applicable Federal regulations. Thus, in reviewing 111(d)/129 Federal Plan delegation requests, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA and the EPA's implementing regulations. Accordingly, this action merely notifies the public of the EPA's receipt of DCDOEE's negative declarations for large municipal waste combustors, crude oil and natural gas facilities, and electric utility generating units and does not impose additional requirements. For that reason, the EPA concludes the following.

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

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

This action does not impose an information collection burden under the PRA (44 U.S.C. 3501 et seq. ) because it does not contain any information collection activities.

This action 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. ). This action merely delegates to the local agency the authority to implement the already applicable requirements of the Federal Plan.

This action does not contain any unfunded mandate, as described in the Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1531-1538) and does not significantly or uniquely affect small governments.

This action does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999) because it will not have substantial direct effects on the states, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

Executive Order 13045 directs Federal agencies to include an evaluation of the health and safety effects of the planned regulation on children in Federal health and safety standards and explain why the regulation is preferable to potentially effective and reasonably feasible alternatives. This action is not subject to Executive Order 13045 because it is not a significant regulatory action under section 3(f)(1) of Executive Order 12866, and because the EPA does not believe the environmental health or safety risks addressed by this action present a disproportionate risk to children.

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

This rulemaking does not involve technical standards. This action is not subject to the 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 Clean Air Act.

This action does not have tribal implications as specified in Executive Order 13175. Thus, Executive Order 13175 does not apply to this action.

On June 17, 2025, the Regional Administrator for EPA Region III signed a Memorandum of Agreement (MoA) which is the mechanism for the transfer of authority between the EPA and the ACHD and defines the policies, responsibilities and procedures by which the ACHD will implement and enforce the Federal Plan for existing SSI units. The EPA is proposing to approve the ACHD request for delegation of authority to implement and enforce the SSI Federal Plan found at 40 CFR part 62 subpart LLL and to adhere to the terms and conditions prescribed in the MoA signed by the EPA and representatives of Allegheny County and the ACHD, as explained further in this action. The purpose of this SSI Federal Plan delegation is to transfer primary implementation and enforcement responsibility from the EPA to the ACHD for all affected facilities within the jurisdiction of Allegheny County. However, nothing in this action, nor in the MoA, shall be construed to prohibit the EPA from enforcing the SSI Federal Plan.

Sections 111(d) and 129 of the CAA require states to submit plans to control certain pollutants (designated pollutants) at existing solid waste combustor facilities (designated facilities) whenever standards of performance have been established under section 111(b) for new sources of the same type and the EPA has established emission guidelines for such existing sources. A designated pollutant is any pollutant for which no air quality criteria has been issued or which is not included on a list published under section 108(a) (national ambient air quality standards) or section 112 (hazardous air pollutants) of the CAA, but emissions of which would be subject to a standard of performance for new stationary sources under section 111(b). In addition, section 129 of the CAA also requires the EPA to promulgate emission guidelines for solid waste incineration units that emit specific air pollutants or a mixture of air pollutants. These pollutants include organics (dioxins and dibenzofurans), carbon monoxide, metals (cadmium, lead and mercury), acid gases (hydrogen chloride, sulfur dioxide and oxides of nitrogen), particulate matter and opacity (as appropriate).

On March 21, 2011 (76 FR 15372), the EPA promulgated new source performance standards and emission guidelines for SSI units at 40 CFR part 60 subparts LLLL and MMMM, respectively. The designated facilities to which the emission guidelines apply are existing SSI units, as stipulated in subpart MMMM, that commenced construction on or before October 14, 2010.

Pursuant to section 129(b)(2) of the CAA, state plan requirements must be “at least as protective” as the emission guidelines and become federally enforceable upon approval by the EPA. The procedures for adoption and submittal of state plans are codified in 40 CFR part 60, subpart B. For states that fail to submit a state plan, the EPA is required to develop and implement a Federal Plan within two years following promulgation of the emission guidelines. 42 U.S.C. 7429(b)(3). The EPA implementation and enforcement of the Federal Plan is viewed as an interim measure until states assume their role as the preferred implementers of the emission guidelines requirements stipulated in the Federal Plan. Accordingly, the EPA promulgated the SSI Federal Plan on April 29, 2016 (81 FR 26040) which is codified at 40 CFR part 62, subpart LLL. In that rulemaking, the EPA strongly encouraged state and local agencies in jurisdictions that did not submit approvable state plans to request delegation of the SSI Federal Plan so that they can have the primary responsibility for implementing and enforcing regulations affecting existing source SSI units, consistent with the intent of section 129 of the CAA. 81 FR 26040, 26055 (April 29, 2016).

On November 13, 2017, the ACHD submitted to the EPA a request for delegation of authority to implement and enforce the SSI Federal Plan. The scope of the request includes only the geographical area of Allegheny County. The EPA evaluated the ACHD request for delegation pursuant to the provisions of the SSI Federal Plan and the EPA's Delegation Manual. 1 40 CFR 62.15865 of the SSI Federal Plan establishes that a state may meet its CAA section 111(d)/129 obligations by submitting an acceptable written request for delegation of the Federal Plan that includes the following requirements: (1) a demonstration of adequate resources and legal authority to administer and enforce the Federal Plan; (2) an inventory of affected SSI units, an inventory of emissions from affected SSI units, and provisions for state progress reports (see items under 40 CFR 60.5015(a)(1), (2) and (7) from the SSI emission guidelines); (3) certification that the hearing on the state delegation request, similar to the hearing for a state plan submittal, was held, a list of witnesses and their organizational affiliations, if any, appearing at the hearing, and a brief written summary of each presentation or written submission; and (4) a commitment to enter into an MoA with the Regional Administrator that sets forth the terms, conditions and effective date of the delegation and that serves as the mechanism for the transfer of authority.

Under the EPA's Delegation Manual, item 7-139, the Regional Administrator is authorized to delegate implementation and enforcement of sections 111(d)/129 Federal Plans to states. The Regional Administrator may consider delegating authority to implement and enforce Federal Plans to a state provided the following conditions are met: (1) the state does not already have an EPA approved state plan; (2) the state submits a demonstration of adequate resources and legal authority to administer and enforce the Federal Plan; and (3) the state enters into an MoA with the Regional Administrator that sets forth the terms, conditions and effective date of the delegation and that serves as the mechanism for the transfer of authority.

In parallel with our review of the delegation request, the EPA prepared the MoA which defines the policies, responsibilities, and procedures by which the SSI Federal Plan will be administered and enforced by both the ACHD and the EPA.

Both the EPA and Allegheny County signed the MoA in which the parties agreed to the terms and conditions regarding the policies, responsibilities, and procedures for the implementation and enforcement of the delegated SSI Federal Plan. The MoA is the mechanism for the transfer of authority from the EPA to the ACHD. The MoA became effective upon signature by the EPA on June 17, 2025.

The ACHD has met all the EPA's delegation requirements as described above. The reader may view the ACHD letter to the EPA requesting delegation and the MoA signed by both parties at www.regulations.gov, identified by Docket ID Number EPA-R03-OAR-2025-0487.

The EPA has evaluated the ACHD delegation request submittal for consistency with the CAA, EPA regulations, and EPA policy. The ACHD has met all the requirements for obtaining delegation of authority to implement and enforce the SSI Federal Plan. Allegheny County entered into an MoA with the EPA, and it became effective on June 17, 2025. Accordingly, the EPA is proposing to approve the ACHD request dated November 13, 2017 for delegation of authority to implement and enforce the Federal Plan for existing SSI units. The EPA will continue to retain certain specific authorities reserved to the EPA in the SSI Federal Plan, as indicated in the MoA ( e.g., authority to approve major alternatives to test methods or monitoring, etc.), and as required under 40 CFR 62.16050.

Under the CAA, the EPA has the authority to delegate to a state or local agency the authority to implement a 111(d)/129 Federal Plan so long as the delegation complies with the provisions of the CAA and applicable Federal regulations. 42 U.S.C. 7411(d) and 7429(b)(3); 40 CFR 60.5045; 40 CFR 62.15865. In reviewing 111(d)/129 Federal Plan delegation requests, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA and the EPA's implementing regulations. Accordingly, this action merely proposes to codify in the Code of Federal Regulations the EPA's delegation of authority to the ACHD to administer the Federal Plan and does not impose additional requirements beyond those imposed by the already applicable SSI Federal Plan.

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

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

This action does not impose an information collection burden under the PRA (44 U.S.C. 3501 et seq. ) because it does not contain any information collection activities.

This action 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. ). This action merely delegates to the local agency the authority to implement the already applicable requirements of the Federal Plan.

This action does not contain any unfunded mandate, as described in the Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1531-1538) and does not significantly or uniquely affect small governments.

This action does not have federalism implications as specified in Executive Order 13132 (64 FR 43255, August 10, 1999) because it will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government.

Executive Order 13045 directs Federal agencies to include an evaluation of the health and safety effects of the planned regulation on children in Federal health and safety standards and explain why the regulation is preferable to potentially effective and reasonably feasible alternatives. This action is not subject to Executive Order 13045 because it is not a significant regulatory action under section 3(f)(1) of Executive Order 12866, and because the EPA does not believe the environmental health or safety risks addressed by this action present a disproportionate risk to children. This action merely delegates to a local agency the authority to administer the already applicable SSI Federal Plan.

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

This rulemaking does not involve technical standards. This action merely delegates to a local agency the authority to administer the already applicable SSI Federal Plan.

This action does not have tribal implications as specified in Executive Order 13175. Thus, Executive Order 13175 does not apply to this action.

Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA.

The EPA requires all major stationary sources of air pollution and certain other sources to obtain operating permits under title V of the CAA and 40 CFR part 70. The State of Maine, through the Department of Environmental Protection (DEP), submitted its operating permit program to the EPA for approval on October 23, 1995. EPA granted source-category limited interim approval on February 21, 1997. See 61 FR 49292-49293 (September 19, 1996) for a complete discussion of the conditions for full approval. On September 28, 2001, EPA received Maine's revisions to its program that address the conditions described in EPA's interim approval. EPA granted full approval on December 17, 2001. See 66 FR 52874. The Maine DEP implements the title V operating permit program through its Chapter 140: Part 70 Air Emission License Regulation. EPA approved additional revisions to Maine's title V operating permit program in 2011. Maine's program approvals are listed in 40 CFR part 70, Appendix A.

On July 29, 2024, the Maine DEP submitted to EPA revisions to its operating permit program at 06-096 CMR Chapter 140, “Part 70 Air Emission License Regulation,” to remove the emergency affirmative defense provisions and make minor changes that are considered clarifications, that correct grammar, that codify longstanding practices, or that are necessary to utilize an expected future electronic application system. The revisions also include provisions allowing the public comment period on a draft permit to run concurrently with EPA's review of a proposed permit. The EPA is not taking action on the removal of the emergency affirmative defense provisions in Section 2(AA) of Chapter 140 at this time. The EPA intends to address Maine's request to approve the revisions removing the emergency affirmative defense provisions in a subsequent action.

The State's formal rulemaking process began on March 7, 2024, when the Maine DEP presented its proposal to the Maine Board of Environmental Protection. Maine DEP states that a public hearing was not required under state law at 38 MRS § 585, because the proposed rulemaking did not establish new emission standards or make changes to existing emission standards. However, this rule implements a federal program, and federal regulations require the opportunity for a public hearing. Therefore, Maine held a hearing on April 18, 2024. No persons attended the hearing to provide testimony, but DEP did receive written comments during the comment period, which closed on April 29, 2024. Maine's final rule incorporates minor changes based on the comments DEP received. This rulemaking was completed and adopted by Maine DEP and became effective at the state level on July 8, 2024.

The State's July 29, 2024, submittal requests EPA approval of the following revisions to Maine's existing EPA-approved CAA title V operating permit program:

• Removal of inappropriate references to New Source Review permitting. New Source Review is addressed by the Maine DEP's Chapter 115;

• Allowing applications to be signed electronically provided the signature complies with the requirements of Cross-Media Electronic Reporting, 40 CFR part 3;

• Allowing public notices of intent to file and draft availability to be published on the Maine DEP website in lieu of publication in a print newspaper;

• Allowing the Maine DEP to keep records for public inspection electronically rather than requiring a paper copy at the Augusta, Maine office;

• Adding further information regarding the applicability of Section 502(b)(10); and

• Requiring transfer applications to be completed within 60 days as is required by the underlying federal regulation.

The Maine DEP also codified the following revisions to align the rule with longstanding practices and seeks approval of these changes into their EPA-approved CAA title V operating permit program:

• Clarifying that Maine DEP, and not the applicant, will provide draft licenses to affected states when appropriate;

• Removing the requirement for applicants to submit redlined versions of previous applications when applying for a license renewal;

• Specifying that EPA's review period on a draft license may run concurrently with the public comment period provided the State does not receive comments that cause it to make substantive changes to the draft license; and

• Clarifying that portable engines not used to power process equipment are considered insignificant activities.

The EPA has reviewed the State's July 29, 2024, revisions made to Chapter 140: Part 70 Air Emission License Regulation. As stated above, the EPA is not taking action on the removal of the emergency affirmative defense provisions in Section 2(AA) of Chapter 140 Part 70 Air Emission License Regulation, at this time. The EPA will address Maine's request to remove the emergency affirmative defense provisions in a subsequent action.

EPA considers the majority of Maine's other revisions to be administrative in nature and consistent with the requirements in title V of the CAA and 40 CFR part 70. The revisions did not establish new emission standards or make changes to existing emission standards, and no change is inconsistent with the CAA title V provisions or EPA's 40 CFR part 70 operating permits program regulations. The revisions focus on clarifying procedures, modernizing administrative processes, and improving consistency with federal regulations.

Maine's revisions allowing DEP to conduct the 30-day public comment period concurrent with EPA 45-day review period, under certain circumstances, are consistent with the Act and authorized by EPA regulations. In 2020 amendments to part 70, EPA recognized that some permitting authorities conduct the public comment period and 45-day EPA review period concurrently for some permits, particularly in situations where the permitting authority does not anticipate receiving significant public comments on the draft permit. 85 FR 6431 at 6436 (February 5, 2020); 40 CFR 70.8(a)(1)(ii). Maine's revisions to Chapter 140 allow DEP to use concurrent review periods, except in cases where DEP “receives comments from the public or affected states that lead [DEP] to make substantive changes to the draft/proposed license.” 06-096 CMR Chapter 140 §§ 3(G), 6(G), 9(G), 10(G). Maine's revisions also recognize that, if DEP refuses to accept an affected state's comments, the EPA 45-day review period will not start until DEP provides EPA with a written explanation of such refusal. See, e.g., id. § 2(L)(2). Further, EPA's regulations provide that the EPA will not consider its review period to have run if a permitting authority receives significant comment on a draft permit during the public participation process. 40 CFR 70.8(a)(1)(ii); see also 85 FR at 6441 & n.11. In such instances, the permitting authority must make any revisions to the permit and permit record necessary to address such public comments, including preparing a written response to comments, and submit the proposed permit and response to comments to EPA after the public comment period has closed. 40 CFR 70.8(a)(1)(ii). In these cases, EPA's review period does not begin until EPA has received all required materials from the State. Id.

EPA proposes to approve Maine's revisions to Chapter 140 that allow concurrent review because the revisions do not allow concurrent review in cases where DEP makes substantive changes to a draft permit based on comments from the public or an affected state or where DEP refuses to accept an affected state's comments, as described above. Further, 40 CFR 70.8(a)(1)(ii) ensures that, if DEP receives significant public comment that does not result in a substantive change to the permit, the 45-day EPA review period does not begin until DEP provides EPA with a written response to all significant comments raised during the public participation process. For these reasons, EPA proposes that Maine's revisions regarding concurrent review meet the requirements of part 70 and of the Act.

EPA is proposing to approve the above-discussed revisions to Maine DEP's operating permit program at Chapter 140, “Part 70 Air Emission License Regulation,” except those in section 2(AA) related to affirmative defense, which EPA intends to address at a later date. EPA is soliciting public comments on the issues discussed in this notice or on other relevant matters. These comments will be considered before taking final action. Interested parties may participate in the Federal rulemaking procedure by submitting written comments to this proposed rule by following the instructions listed in the ADDRESSES section of this Federal Register .

Under the CAA, the Administrator approves title V operating permit program revisions that comply with the Act and applicable Federal Regulations. See 42 U.S.C. 7661a(d). Thus, in reviewing title V operating permit program submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the CAA. This action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders12866 (58 FR 51735, October 4, 1993);

• 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 subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and

• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA.

This rule does not have tribal implications as specified by Executive Order 13175 (65 FR 67249, November 9, 2000), because the title V action is not approved to apply in Indian country located in the State, and the EPA notes that it will not impose substantial direct costs on tribal governments or preempt tribal law.

Throughout this document whenever “we,” “us,” or “our” is used, we mean EPA.

Section 112 of the CAA regulates hazardous air pollutants (HAPs), also known as air toxics, which are air pollutants that present a threat of adverse human health effects, such as cancer. The CAA specifically defines a HAP as any air pollutant listed pursuant to 42 U.S.C. 7412(b). This list currently has 189 HAPs organized by chemical name and CAS number and may be revised by the Administrator pursuant to 42 U.S.C. 7412(b)(2). According to 42 U.S.C. 7412(b)(3), any person may petition the Administrator to modify the list of HAPs by adding or deleting a substance. The Administrator may add a substance to the HAP list when a determination is made that the substance is an air pollutant and that emissions, ambient concentrations, bioaccumulation or deposition of the substance are known to cause or may reasonably be anticipated to cause adverse effects to human health or adverse environmental effects. Effective February 4, 2022, EPA added 1-bromopropane (1-BP) to the HAP list (87 FR 393). This amendment was promulgated at 40 CFR 63.64.

Under the CAA Amendments of 1990, state and local permitting authorities are required to develop operating permit programs under title V of the CAA (42 U.S.C. 7661-7661f). HAPs are regulated air pollutants subject to title V operating permit programs consistent with the requirements of 40 CFR part 70—State Operating Permit Programs. See 40 CFR 70.2 Air pollution sources utilize the HAP list to calculate HAP emissions in determining applicable title V operating permit requirements.

As a result of the HAP list modification in 2022, state environmental agencies were required to incorporate 1-BP into their state regulations and title V operating permit programs. The New Hampshire Department of Environmental Services (NHDES) revised New Hampshire Code of Administrative Rules, Chapter Env-A—Air Related Programs (Env-A) to comply with the CAA. NHDES revised the definition of “hazardous air pollutant” at Env-A 103.41 and the definition of “regulated air pollutant” at Env-A 104.47. The amended language at Env-A 103.41 states that, “`Hazardous air pollutant' means any air pollutant listed pursuant to section 112(b) of the Act.” The amended language at Env-A 104.47 states, “Regulated air pollutant means `Regulated air pollutant' as defined in 40 CFR 70.2, reprinted in Appendix D.” These revisions require the state to incorporate all current and future HAPs into its title V operating permit program, such as the newly added 1-BP.

On June 12, 2025, NHDES formally submitted the revised definitions to EPA, providing a copy of the official state rule and certification of adoption. On July 31, 2025, NHDES submitted a supplemental letter clarifying that the purpose of the previous submittal was to revise the definitions in its title V operating permit program pursuant to 40 CFR 70.4(i).

Upon review, EPA finds that the permit program's revised definitions of “hazardous air pollutant” and “regulated air pollutant” are consistent with Federal definitions at CAA section 112(b) and 40 CFR 70.2. The revised definitions have the intended effect of incorporating changes to the EPA list of HAPs, including the recent addition of 1-BP, into the state's CAA title V permitting program.

According to 40 CFR 70.4(i)(2)(i), a state's obligation to revise it's CAA title V operating permit program shall be accomplished as follows: “The State shall submit a modified program description, Attorney General's statement, or such other documents as EPA determines to be necessary.” EPA deems NHDES's submitted materials for revision of its title V operating permit program to be adequate and satisfy the requirements of 40 CFR 70.4(i)(2)(i).

EPA is proposing to approve NHDES's title V operating permit program revisions. EPA is soliciting public comments on the issues discussed in this notice or on other relevant matters. These comments will be considered before taking final action. Interested parties may participate in the Federal rulemaking procedure by submitting written comments to this proposed rule by following the instructions listed in the ADDRESSES section of this Federal Register .

EPA is proposing to include incorporation by reference in a final rule regulatory text. In accordance with requirements of 1 CFR 51.5, EPA is proposing to incorporate by reference the definitions at Env-A 103.41 and at Env-A 104.47 discussed in sections II and III of this preamble. EPA has made, and will continue to make, these documents generally available through https://www.regulations.gov and at EPA Region 1 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

Under the CAA, the Administrator is required to approve title V operating permit program revisions that comply with the provisions of the CAA and applicable Federal regulations. Thus, in reviewing revisions, EPA's role is to approve state choices, provided that they meet the criteria of the CAA. Accordingly, this proposed action merely approves state law as meeting Federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

• Is not a significant regulatory action subject to review by the Office of Management and Budget under Executive Orders12866 (58 FR 51735, October 4, 1993);

• 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 subject to Executive Order 13045 (62 FR 19885, April 23, 1997) because it approves a state program;

• Is not a significant regulatory action subject to Executive Order 13211 (66 FR 28355, May 22, 2001); and

• Is not subject to requirements of Section 12(d) of the National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) because application of those requirements would be inconsistent with the CAA.

In addition, this action is not approved to apply on any Indian reservation land or in any other area where EPA or an Indian tribe has demonstrated that a tribe has jurisdiction. In those areas of Indian country, the rule does not have tribal implications and will not impose substantial direct costs on tribal governments or preempt tribal law as specified by Executive Order 13175 (65 FR 67249, November 9, 2000).

Throughout this document, wherever “we,” “us,” or “our” are used, it is intended to refer to the EPA.

In this action, the EPA is proposing to approve Pennsylvania's September 4, 2025 redesignation request as satisfying the requirements of CAA section 107(d)(3)(E) and redesignate the Allegheny County Area  1 from nonattainment to attainment of the 2012 annual PM 2.5 NAAQS. The EPA has already approved, as a revision to Pennsylvania's SIP, a maintenance plan that demonstrates maintenance of the 2012 annual PM 2.5 NAAQS through 2035 in the Allegheny County Area. See 90 FR 34770 (July 24, 2025).

Fine particulate pollution can be emitted directly from a source (primary PM 2.5 ) or formed secondarily through chemical reactions in the atmosphere involving precursor pollutants emitted from a variety of sources. The main precursors of secondary PM 2.5 are sulfur dioxide (SO 2 ), nitrogen oxides (NO X ), ammonia (NH 3 ), and volatile organic compounds (VOCs). 2 Sulfates are a type of secondary particulate formed from SO 2 emissions from power plants and industrial facilities. Nitrates, another common type of secondary particulate, are formed from combustion emissions of NO X from power plants, mobile sources, and other combustion sources.

On January 15, 2013 (78 FR 3086), the EPA promulgated a revised primary annual PM 2.5 NAAQS to provide increased protection of public health from fine particle pollution. In that action, the EPA strengthened the primary annual PM 2.5 standard from 15.0 micrograms per cubic meter (µg/m 3 ) to 12.0 µg/m 3 , which is attained when the 3-year average of the annual arithmetic means does not exceed 12.0 µg/m 3 . On January 15, 2015 (80 FR 2206), the EPA published air quality designations for the 2012 annual PM 2.5 NAAQS. In that action, the EPA designated all municipalities in Allegheny County, Pennsylvania (Allegheny County Area) as one moderate nonattainment area for the 2012 annual PM 2.5 NAAQS. See 40 CFR 81.339.

On March 16, 2022 (87 FR 14799), the EPA determined that the Allegheny County Area had clean data and attained the 2012 annual PM 2.5 NAAQS based on certified air quality data from 2018-2020. That action suspended the requirement for the Allegheny County Area to submit an attainment demonstration and associated reasonably available control measures (RACM), including reasonably available control technology (RACT), a reasonable further progress (RFP) plan, and contingency measures for failure to attain or meet RFP. These requirements are suspended for so long as the Allegheny County Area continues to attain the standard. When the Area is redesignated to attainment, these requirements are permanently discharged. Nonetheless, the EPA approved most elements of Pennsylvania's comprehensive plan to ensure timely attainment of the 2012 annual PM 2.5 NAAQS for the Allegheny County Area (Allegheny County PM 2.5 Attainment Plan), including an attainment demonstration, a RACM/RACT analysis, and an RFP analysis, along with a 2011 base year emissions inventory, a particulate matter precursor contribution demonstration, quantitative milestones to ensure timely attainment, and a motor vehicle emissions budget (MVEB) specific to the 2012 annual PM 2.5 NAAQS. 3 On May 19, 2023 (88 FR 32117), the EPA determined that the Allegheny County Area had attained the 2012 annual PM 2.5 NAAQS by the applicable attainment date based on certified air quality data from 2019-2021.

On July 24, 2025 (90 FR 34770), the EPA approved, as a revision to the Pennsylvania SIP, a maintenance plan that demonstrates maintenance of the 2012 annual PM 2.5 NAAQS through 2035 in the Allegheny County Area.

The CAA provides the requirements for redesignating a nonattainment area to attainment. Specifically, section 107(d)(3)(E) of the CAA allows for redesignation provided that: (1) the EPA determines that the area has attained the applicable NAAQS; (2) the EPA has fully approved the applicable implementation plan for the area under section 110(k); (3) the EPA determines that the improvement in air quality is due to permanent and enforceable reductions in emissions resulting from implementation of the applicable SIP and applicable Federal air pollutant control regulations and other permanent and enforceable reductions; (4) the EPA has fully approved a maintenance plan for the area as meeting the requirements of section 175A of the CAA; and (5) the state containing such area has met all requirements applicable to the area under section 110 and part D of the CAA. Each of these requirements are discussed in section IV of this document.

The EPA has provided guidance on redesignations in the “SIPs; General Preamble for the Implementation of title I of the CAA Amendments of 1990,” (the General Preamble)  4 and has provided further guidance on processing redesignation requests in the following documents: (1) “Procedures for Processing Requests to Redesignate Areas to Attainment,” Memorandum from John Calcagni, Director, Air Quality Management Division, September 4, 1992 (hereafter referred to as the 1992 Calcagni Memorandum or Calcagni Memo); (2) “SIP Actions Submitted in Response to CAA Deadlines,” Memorandum from John Calcagni, Director, Air Quality Management Division, October 28, 1992; and (3) “Part D New Source Review (Part D NSR) Requirements for Areas Requesting Redesignation to Attainment,” Memorandum from Mary D. Nichols, Assistant Administrator for Air and Radiation, October 14, 1994. These documents are included in the docket for this proposed action.

The EPA is proposing to redesignate the Allegheny County Area to attainment for the 2012 annual PM 2.5 NAAQS. The EPA's proposed approval of the state's redesignation request is based upon the EPA's determination that the Allegheny County Area continues to attain the 2012 annual PM 2.5 NAAQS and that all other redesignation criteria have been met for the Allegheny County Area. The following is description of how Pennsylvania's September 4, 2025 submission satisfies the requirements of section 107(d)(3)(E) of the CAA for the 2012 annual PM 2.5 NAAQS.

To redesignate an area from nonattainment to attainment, the CAA requires the EPA to determine that the area has attained the applicable NAAQS (CAA section 107(d)(3)(E)(i)). Under the EPA's regulations at 40 CFR 50.18 and 40 CFR part 50, appendix N, the 2012 annual PM 2.5 NAAQS is met when the annual PM 2.5 NAAQS design value (DV) is less than or equal to 12.0 µg/m 3 at all monitoring sites in the area. 5 The relevant data must be collected and quality-assured in accordance with 40 CFR part 58 and recorded in the EPA Air Quality System (AQS) database.

As referenced previously, on March 16, 2022 (87 FR 14799), the EPA determined that the Allegheny County Area had clean data and attained the 2012 annual PM 2.5 NAAQS based on certified air quality data from 2018-2020. Additionally, on May 19, 2023 (88 FR 32117), the EPA determined that the Allegheny County Area had attained the 2012 annual PM 2.5 NAAQS by the applicable attainment date based on certified air quality data from 2019-2021. The basis and effect of these determinations of attainment for the 2012 annual PM 2.5 NAAQS were discussed in the publications of the proposed and final rules which determined the Allegheny County Area attained the 2012 PM 2.5 NAAQS. 6

In addition, the EPA has reviewed the most recent ambient air quality PM 2.5 monitoring data in the Allegheny County Area consistent with the requirements contained in 40 CFR part 58 and recorded in the EPA's AQS. The quality-assured, quality-controlled, and state-certified 2018 to 2024 PM 2.5 air quality data show that the Allegheny County Area attained and continues to attain the 2012 annual PM 2.5 NAAQS. Therefore, the EPA is proposing to determine that the Allegheny County Area is attaining the 2012 annual PM 2.5 NAAQS. This proposed determination is based on the most recent three years of complete, quality-assured, quality-controlled, and certified data, which is for the 2022-2024 monitoring period. The monitoring data is summarized in Tables 1 and 2, in this document, and is also included in the docket for this rulemaking available online at www.regulations.gov, Docket ID: EPA-R03-OAR-2025-1777.

This is a summary of the Commission's Fifth Further Notice of Proposed Rulemaking ( FNPRM ), FCC 25-72, adopted on October 28, 2025 and released on October 29, 2025. The full text of this document is available electronically via the FCC's Electronic Document Management System (EDOCS) website at https://docs.fcc.gov/public/attachments/FCC-25-72A1.pdf or via the FCC's Electronic Comment Filing System (ECFS) website at https://www.fcc.gov/ecfs (search using docket number). (Documents will be available electronically in ASCII, Microsoft Word, and/or Adobe Acrobat.)

Paperwork Reduction Act. This document contains possible new or modified information collection requirements. The Commission, as part of its continuing effort to reduce paperwork burdens, invites the general public and the Office of Management and Budget (OMB) to comment on the information collection requirements contained in this document, as required by the Paperwork Reduction Act (PRA) of 1995, Public Law 104-13. Public and agency comments are due January 20, 2026.

Providing Accountability Through Transparency Act: Consistent with the Providing Accountability Through Transparency Act, Public Law 118-9, a summary of this document will be available on https://www.fcc.gov/proposed-rulemakings.

Comments should address: (a) whether the proposed collection of information is necessary for the proper performance of the functions of the Commission, including whether the information shall have practical utility; (b) the accuracy of the Commission's burden estimates; (c) ways to enhance the quality, utility, and clarity of the information collected; (d) ways to minimize the burden of the collection of information on the respondents, including the use of automated collection techniques or other forms of information technology; and (e) way to further reduce the information collection burden on small business concerns with fewer than 25 employees. In addition, pursuant to the Small Business Paperwork Relief Act of 2002, Public Law 107-198, see 44 U.S.C. 3506(c)(4), the Commission seeks specific comment on how the Commission might further reduce the information collection burden for small business concerns with fewer than 25 employees.

OMB Control Number: 3060-1254.

Title: Next Gen TV/ATSC 3.0 Local Simulcasting Rules; 47 CFR 73.3801 (full-power TV), 73.6029 (Class A TV), and 74.782 (low-power TV) and FCC Form 2100 (Next Gen TV License Application).

Form No.: FCC Form 2100 (Next Gen TV License Application).

Type of Review: Revision of currently approved collection.

Respondents: Business or other for-profit entities, state, local, or tribal government and not for profit institutions.

Number of Respondents and Responses: 1,422 respondents; 11,460 responses.

Estimated Time per Response: 0.017-8 hours.

Frequency of Response: On occasion reporting requirement; Recordkeeping requirement; Third party disclosure.

Obligation to Respond: Required to obtain or retain benefits.

Statutory authority for this collection of information is contained in sections 1, 4, 7, 301, 303, 307, 308, 309, 316, 319, 325(b), 336, 338, 399b, 403, 614, and 615 of the Communications Act of 1934, as amended, 47 U.S.C. 151, 154, 157, 301, 303, 307, 308, 309, 316, 319, 325(b), 336, 338, 399b, 403, 534, and 535.

Total Annual Burden: 3,852 hours.

Total Annual Cost: $147,000.

Needs and Uses: The FNPRM proposes to permit simulcasting stations, upon notice to the Commission, to encode multicast 1.0 streams using MPEG-4.

Synopsis:

1. America's television broadcasters are in the midst of a transition. They are shifting to a new standard in broadcasting that can deliver significant and new benefits to consumers across the country. Indeed, Next Gen TV, also called ATSC 3.0, represents the future of broadcast television. Next Gen TV promises to revitalize the nation's free, local, over-the-air (OTA) television service, which serves as a vital source of local news and information for many Americans, by enabling significant improvements in picture quality, audio clarity, interactive features, and public safety and accessibility capabilities. We expect this will enable broadcasters to remain competitive in the video marketplace for years to come. To achieve this future, broadcasters have undertaken a complex and challenging technological transition without the allocation of additional spectrum. Broadcasters have made progress toward this transition, having launched ATSC 3.0 (or “3.0”) service in more than 90 markets that include more than 70 percent of the country's population. 1 Actions proposed today support continued progress in the ongoing transition to ATSC 3.0.

2. Herein we take steps to support and accelerate the nation's ongoing market-based broadcast television transition to ATSC 3.0. We propose to remove unnecessary regulatory obstacles and give substantial flexibility to broadcasters because at this point in the transition they are best positioned to determine how to continue to serve their viewers while rolling out 3.0 services. Most notably, we propose to end the simulcasting requirement. In addition, we seek comment on how to minimize the costs and impact of this transition on all stakeholders, including consumers, manufacturers, MVPDs, and smaller broadcasters.

3. In 2017, the Commission authorized television broadcasters to use the ATSC 3.0 transmission standard on a voluntary, market-driven basis. 2 The Commission required that any broadcaster voluntarily deploying ATSC 3.0 service must, with very limited exceptions, 3 continue to air at least their primary stream using the current-generation TV transmission standard, also called “ATSC 1.0” or “1.0.”  4 This is because the Next Gen TV standard is not backward-compatible with most existing TV sets or receivers, which have only ATSC 1.0 and analog tuners. Because a TV station cannot, as a technical matter, simultaneously broadcast in both 1.0 and 3.0 format from the same facility on the same physical channel, “local simulcasting” must be effectuated through partnerships that broadcasters seeking to provide Next Gen TV service enter into with other broadcasters in their local markets. 5 The Commission, however, intended that the local simulcasting requirement be temporary.

4. Prior to deploying 3.0 service, stations must file an application with the Commission to modify their existing license and receive Commission approval. Review of applications to deploy ATSC 3.0 service includes consideration of the coverage that would be provided by a Next Gen TV station's ATSC 1.0 simulcast signal. 6 The Commission sought to minimize disruption to viewers resulting from the deployment of ATSC 3.0 while recognizing that if a station moves its ATSC 1.0 signal to a partner simulcast host station with a different transmitter location, some OTA viewers may no longer be able to receive the station's 1.0 signal unless they acquire a 3.0 capable television receiver. Among other obligations, the Commission requires the Next Gen TV station to select a partner 1.0 simulcast host station that is assigned to its same designated market area (DMA) and from which it will continue to provide ATSC 1.0 simulcast service to its entire community of license. The Commission also stated that an application demonstrating that the station would provide ATSC 1.0 simulcast service to at least 95 percent of the predicted population within the station's original noise limited service contour (NLSC) would be presumptively in the public interest and afforded “expedited processing.” All other applications require a more detailed public interest analysis by the Commission prior to action.

5. Substantially Similar Rule. In the First Next Gen TV Report and Order, the Commission adopted a requirement that the programming aired on a Next Gen TV station's ATSC 1.0 simulcast channel be “substantially similar” to that of the primary video programming stream on the ATSC 3.0 channel. This rule, which is distinct from the simulcasting requirement itself, 7 means that the programming on the two versions of the primary stream must generally be the same. The rule was initially scheduled to sunset on July 17, 2023, and was extended to July 17, 2027.

6. Requirement to Comply with the ATSC A/322 Standard. In authorizing use of the Next Gen TV broadcast transmission standard, the Commission in the First Next Gen TV Report and Order required compliance with only two parts of the ATSC 3.0 suite of standards: (1) A/321, the standard used to communicate the RF signal type that the ATSC 3.0 signal will use; and (2) A/322, the standard that defines the waveforms that ATSC 3.0 signals may take. 8 In requiring compliance with A/322, the Commission observed that “device manufacturers and MVPDs may not be able to reliably predict what signal modulation a broadcaster is using unless broadcasters are required to follow A/322,” at least with respect to their required primary programming stream. The Commission explained that “[t]his uncertainty could cause manufacturers to inadvertently build equipment that cannot receive Next Gen TV broadcasts or could render MVPDs unable to receive and retransmit the signals of Next Gen TV stations. These outcomes would harm consumers.” The Commission, however, decided that it was not appropriate at the time “to require broadcasters to adhere to A/322 indefinitely,” explaining that “the ATSC 3.0 standard could evolve, and stagnant Commission rules could prevent broadcasters from taking advantage of that evolution.” The Commission thus determined that the requirement to comply with the A/322 standard would expire on March 6, 2023, which was later extended until July 17, 2027.

7. In January 2025, the National Association of Broadcasters (NAB) filed a report summarizing the discussions and progress made through the Future of Television Initiative (FOTVI), and in February 2025, NAB filed the Petition asking the Commission to “establish a clear timeline to complete the transition” to ATSC 3.0. In April 2025, the Media Bureau issued a Public Notice seeking comment on NAB's Petition, the FOTVI Report, and other related issues. 9 The Bureau received more than 900 comments and replies in response. The comment cycle closed on June 6, 2025.

8. Petition. NAB proposes that the Commission mandate a two-part deadline to complete the full-power 3.0 transition. Per the NAB proposal, full-power stations in the top 55 markets (available to about 70 percent of viewers in the country) would be required to transition fully to ATSC 3.0 ( i.e., end all ATSC 1.0 broadcasting, including simulcasting) in February 2028, with limited waivers for “smaller,” independent, and noncommercial stations if necessary. Full-power stations in the remaining markets would be required to transition fully to ATSC 3.0 in February 2030. 10 NAB contends that “[w]ithout decisive and immediate action, the transition risks stalling” and that “[r]eaching the finish line requires industry-wide coordination and engagement—something individual broadcasters cannot do alone.”

9. NAB also proposes that the Commission impose a mandate on television manufacturers to “ensur[e that] consumers who buy new TVs can continue receiving broadcast programming.” Specifically, NAB asks the Commission to amend section 15.117 of its rules to require that all TV broadcast receivers include 3.0 tuners, pursuant to the Commission's authority under the 1962 All Channel Receiver Act (ACRA). 11 According to NAB, “[b]roadcasters would support removing the requirement to include an ATSC 1.0 tuner after the date at which all full-power and class A broadcasters cease transmitting in ATSC 1.0.” NAB also requests that the Commission re-examine what it means to “adequately receive” television channels, as well as “consider adopting a requirement that television receivers make broadcast services available to a consumer in the same or fewer steps needed to access any other video content on the same device.”

10. In addition, NAB asks the Commission to consider whether updates to the MVPD carriage rules are necessary. NAB indicates that some rules, particularly those related to must-carry signals, may need to be revised, such as the “good quality signal” rule. Further, NAB asks the Commission to clarify and/or update certain rules to accelerate deployment. NAB argues that the Commission should relax the 95 percent coverage requirement for expedited application processing and clarify that this coverage requirement should not apply to multicast streams. NAB also urges the Commission to act now to eliminate the “substantially similar” requirement, rather than wait for the scheduled sunset in 2027. Finally, NAB suggests that the Commission should update the incorporations by reference in the rules to the current versions of the ATSC 3.0 standards, ATSC A/321 and ATSC A/322, and may want to consider a variety of other possible changes. 12

11. Future of Television Initiative Report. Launched in April 2023 by NAB, the FOTVI gathered industry, public interest stakeholders, and government  13 to work on a roadmap for the transition of television broadcast from the currently required ATSC 1.0 protocol to ATSC 3.0. The FOTVI Report summarizes the discussions of three working groups, which addressed (1) backwards compatibility, tuner availability and consumer issues; (2) completing the transition; and (3) post-transition regulation. 14 NAB states that it intends the FOTVI Report “will provide the Commission with a better understanding of the remaining issues and concerns of stakeholders and put the Commission in a better position to continue with the rulemaking proceedings necessary to complete a successful transition to ATSC 3.0.”

12. The Commission has been monitoring the pace of the deployment of ATSC 3.0 both nationally and market-by-market, including the rollout of 3.0 service by television broadcasters, the penetration of ATSC 3.0-ready TV sets and other converter equipment, and the extent to which MVPDs have deployed 3.0 equipment. Broadcasters have launched full-power Next Gen TV service in more than 80 markets that contain more than 70 percent of the population. 15 In addition, the FOTVI Report states that more than 14 million ATSC 3.0-capable sets and 300,000 external 3.0 converters were sold through 2024. Further, CTA estimates that by 2028 more than half of TV sets sold each year will have 3.0 tuners even absent Commission action. We are not aware of any MVPDs that are carrying 3.0 signals. 16

13. With this Fifth Further Notice of Proposed Rulemaking ( FNPRM ), we seek to eliminate unnecessary regulatory barriers that hinder continued progress toward a transition to ATSC 3.0, as well as to facilitate the expansion of Next Gen TV service by giving more flexibility to broadcasters and so that viewers can reap the full benefits of this service. First, we make specific proposals and tentative conclusions to further this goal. Second, we seek comment on certain, closely related issues, including an ATSC 3.0 tuner requirement, encryption of broadcast signals, and MVPD carriage of 3.0 signals, in light of our proposals and tentative conclusions, as well as on other outstanding ATSC 3.0 issues.

14. We propose to permit stations to continue to voluntarily transition from a 1.0 signal to a 3.0 signal (or continue to operate in 3.0) while giving them greater freedom to serve the specific needs of their local markets and expeditiously provide next generation television services to viewers. First, we tentatively conclude that we should eliminate the 1.0 simulcasting requirement for stations that transition to 3.0. Second, we tentatively conclude that for stations that wish to continue simulcasting in 1.0 we will continue to permit such operations on a voluntary, simplified basis, by eliminating the “substantially similar” rule and the 95 percent coverage threshold for expedited processing. Third, we propose to permit the use of MPEG-4 on 1.0 streams in certain situations to help enhance broadcasters spectral capacity and thereby facilitate simulcasting until broadcasters and their viewers are ready for a full transition to 3.0. We seek comment on these tentative conclusions and proposals.

15. We tentatively conclude that we should eliminate the 1.0 simulcasting requirement for stations that wish to transition or have transitioned their facilities to 3.0 service. As the Commission made clear at the outset of the 3.0 transition, this requirement was always intended to be temporary, and we believe the time has come for it to be eliminated. Broadcasters have explained that transmitting in both 3.0 and 1.0 “takes enormous capacity and creates significant constraints on what services all participating broadcasters can offer.” Specifically, transitioning broadcasters are generally relying on one or two ATSC 3.0 “lighthouses”  17 in each market, limiting each participant to “only a small fraction of the features” that would be possible if they could devote their entire channel capacity to 3.0. As a result, they have struggled to demonstrate the full array of improvements made possible by this new innovative technology. Based on the Commission's observation of the market since 2017, we have come to believe that while simulcasting remains important for protecting viewers during the transition period, at this stage broadcasters have strong market incentives to continue to effectively serve their viewers.

16. As discussed by the Commission in the First Next Gen TV Report and Order, “[s]tations that do not preserve service coverage or quality will suffer financially due to lost viewership and thus advertising revenue.” In fact, according to the Commission's 2024 Communications Marketplace Report, over half of broadcaster revenue is derived from advertising. Viewers have clear expectations when it comes to the quality of programming they expect from broadcasters and in the current marketplace failure to meet those exceptions will likely drive viewers to other sources for their video programming, such as MVPDs or streaming services. As noted by NAB, “market dynamics are likely to ensure that popular programming remains widely accessible” and as such “[b]roadcasters have no financial incentive to restrict their highest-value content to the still-limited ATSC 3.0 audience.” Broadcasters have also demonstrated the continued importance they place on 1.0 streams through their actions during the transition. Despite Next Gen TV broadcasters not being required to maintain their multicast streams in a 1.0 format, to the Commission's understanding all full power Next Gen TV stations have chosen to preserve their multicast streams under our voluntary 3.0 multicast licensing rules. We believe we can rely on these incentives and marketplace realities to allow broadcasters to decide how and when to move forward with full 3.0 service. We seek comment on these and any additional incentives or factors we should consider when determining whether to eliminate the simulcast requirement as proposed. How does the benefit of removing the simulcast requirement in order to help broadcasters expedite deployment of new enhanced ATSC 3.0 services to consumers balance against the potential costs to consumers who may not yet have 3.0 capable devices and may lose access to OTA 1.0 service? How many households have a TV with an ATSC 3.0 enabled television set or use an ATSC 3.0 converter device? Are there any alternatives to entirely eliminating the simulcast requirement that would still allow broadcasters to more easily deploy 3.0 service and demonstrate to consumers the enhanced features and innovative offerings enabled by 3.0 while continuing to preserve 1.0 service for viewers that do not have the capability to receive 3.0 signals and providing certainty to broadcasters that their signals will be received?

17. We also tentatively conclude that if the simulcast requirement is eliminated as proposed, stations should continue to be free to switch between 1.0 and 3.0 as market conditions dictate, subject to our application and viewer/MVPD notification processes. We seek comment on this conclusion. Some commenters, such as ATVA, express concern that revenue derived from new Broadcast internet services may skew broadcasters' market incentives. However, we tentatively agree with broadcasters, such as Gray, who explain that “datacasting will supplement and support video broadcasting” and “not replace it.”  18 Broadcasters will also remain required to provide a minimum level of broadcast service under our rules.

18. We seek comment on whether to make these new rules effective 30 days after Federal Register publication of an Order adopting this proposal, or on a specific date. If on a specific date, we seek comment on why the proposed date is appropriate. Alternatively, we seek comment on whether we should instead adopt a penetration level and/or market availability threshold for 3.0 receivers that would trigger the elimination of the simulcast requirement; for example, requiring that a certain percentage of viewers in a market have 3.0 devices, or a certain number of 3.0 devices be available for sale in that market, before local broadcasters could cease 1.0 broadcasting. What would be the benefits or burdens of such an approach for consumers, broadcasters, and other stakeholders? We also tentatively conclude that stations seeking to transition without a simulcast host ( i.e. “flash-cut” from 1.0 to 3.0 service), or Next Gen TV stations that wish to end an existing 1.0 simulcast, must file a Next Gen TV license application. We seek comment on this tentative conclusion and comment on any questions we need to update in our forms if we eliminate the simulcast requirement.

19. Finally, we propose to state explicitly in our rules that the existing viewer and MVPD notice requirements for stations also apply to a station that chooses to operate in 3.0 without a simulcast host partner. Although our rules already do not require LPTV and TV translator stations to simulcast, we propose to clarify our part 74 rules to make clear a station's viewer and MVPD notice requirements when it has chosen to simulcast and subsequently decides to terminate 1.0 service. We seek comment on these proposals. 19