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-2025-1367; Project Identifier AD-2024-00719-T” 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 the 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 proposed AD.

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 Luis Cortez-Muniz, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3958; email: Luis.A.Cortez-Muniz@faa.gov. Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this rulemaking.

The FAA issued AD 2013-08-16, Amendment 39-17433 (78 FR 25369, May 1, 2013) (AD 2013-08-16), for The Boeing Company Model 737-700 and -700C series airplanes with certain line numbers. AD 2013-08-16 was prompted by reports of early fatigue cracks at chem-mill areas on the crown skin panels. AD 2013-08-16 requires repetitive inspections for cracking of the fuselage skin at certain locations at chem-mill areas and repair if necessary. AD 2013-08-16 requires the initial inspections before the airplane accumulates 43,000 total flight cycles. AD 2013-08-16 also provides an optional terminating action for the repetitive inspections. The FAA issued AD 2013-08-16 to detect and correct fatigue cracking of the skin panel at the specified chem-mill step locations, which could result in rapid decompression of the airplane.

Since the FAA issued AD 2013-08-16, the FAA received reports of three suspected fuselage fatigue cracks found adjacent to non-chem-mill skin bays on Model 737-700 airplanes with between 40,000 and 43,000 total flight cycles earlier than the inspection thresholds specified by AD 2013-08-16. Boeing has reported that the initial inspection times and repetitive intervals in Boeing Special Attention Service Bulletin 737-53-1310, dated October 20, 2011, are not adequate. The reports indicate that crack growth is faster and cracks are more distributed along the chem-mill steps between the tear straps, resulting in longer cracks than initially observed in the test data that prompted Boeing Special Attention Service Bulletin 737-53-1310, dated October 20, 2011. As a result of these findings, the FAA has determined that reduced inspection thresholds and intervals for the chem-mill areas and the post-modification inspections (for airplanes on which the optional terminating action is accomplished) are now necessary to address the unsafe condition.

The FAA is considering superseding similar ADs for Model 737-600, -800, -900, and -900ER series airplanes, which have crown skin panels that are of a similar design as those on Model 737-700 and -700C series airplanes and may be subject to the same unsafe condition.

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.

The FAA reviewed Boeing Special Attention Service Bulletin 737-53-1310, Revision 1, dated May 22, 2024. This material specifies procedures for repetitive external detailed inspections and either (1) external medium frequency eddy current (MFEC), magneto optic imager (MOI), or C scan inspections or (2) external ultrasonic phased array (UTPA) inspections, and repairing any cracking. This material also describes procedures for installing modification doublers in certain locations, which involves an external detailed inspection and external nondestructive (MFEC, MOI, C-Scan, or UTPA) inspection for any cracking of the area to be modified prior to the doubler being placed on that area, and a high frequency eddy current inspection of all existing holes for cracking. This material specifies that accomplishment of the modification terminates the repetitive inspections provided post-modification inspections are performed for the modified areas.

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.

This proposed AD would require accomplishing the actions specified in the material already described, except for any differences identified as exceptions in the regulatory text of this proposed AD. For information on the procedures and compliance times, see this material at regulations.gov under Docket No. FAA-2025-1367.

The FAA estimates that this AD, if adopted as proposed, would affect 545 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:

The extent of cracking found during the inspections could vary significantly from airplane to airplane. The FAA has no way of determining which conditions may be found on each airplane, the cost to correct or repair each airplane, or the number of airplanes that may require repair.

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 has 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 that the 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 FAA's authority to issue rules regarding aviation safety is found in Title 49 of the United States Code. 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. This rulemaking is promulgated under the authority described in Subtitle VII, Part A, Subpart I, Section 40103. Under that section, the FAA is charged with prescribing regulations to assign the use of the airspace necessary to ensure the safety of aircraft and the efficient use of airspace. This regulation is within the scope of that authority as it would amend the airway structure as necessary to preserve the safe and efficient flow of air traffic within the National Airspace System.

The FAA invites interested persons to participate in this rulemaking by submitting written comments, data, or views. Comments are specifically invited on the overall regulatory, aeronautical, economic, environmental, and energy-related aspects of the proposal. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. To ensure the docket does not contain duplicate comments, commenters should submit only one time if comments are filed electronically, or commenters should send only one copy of written comments if comments are filed in writing.

The FAA will file in the docket all comments it receives, as well as a report summarizing each substantive public contact with FAA personnel concerning this proposed rulemaking. Before acting on this proposal, the FAA will consider all comments it receives on or before the closing date for comments. The FAA will consider comments filed after the comment period has closed if it is possible to do so without incurring expense or delay. The FAA may change this proposal in light of the comments it receives.

Privacy: In accordance with 5 U.S.C. 553(c), DOT solicits comments from the public to better inform its rulemaking process. DOT posts these comments, without edit, including any personal information the commenter provides, to www.regulations.gov, as described in the system of records notice (DOT/ALL-14 FDMS), which can be reviewed at www.dot.gov/privacy.

An electronic copy of this document may be downloaded through the internet at www.regulations.gov. Recently published rulemaking documents can also be accessed through the FAA's web page at www.faa.gov/air_traffic/publications/airspace_amendments/.

You may review the public docket containing the proposal, any comments received and any final disposition in person in the Dockets Operations office (see ADDRESSES section for address, phone number, and hours of operations). An informal docket may also be examined during normal business hours at the office of the Western Service Center, Federal Aviation Administration, 2200 South 216th St., Des Moines, WA 98198.

United States Area Navigation Routes are published in paragraph 2006 and Jet Routes are published in paragraph 2004 of FAA Order JO 7400.11, Airspace Designations and Reporting Points, which is incorporated by reference in 14 CFR 71.1 on an annual basis. This document proposes to amend the current version of that order, FAA Order JO 7400.11J, dated July 31, 2024, and effective September 15, 2024. These updates would be published in the next update to FAA Order JO 7400.11. FAA Order JO 7400.11J, which lists Class A, B, C, D, and E airspace areas, air traffic service routes, and reporting points, is publicly available as listed in the ADDRESSES section of this document.

Jet Route J-517 currently extends between the Boise, ID, Very High Frequency Omnidirectional Range (VOR)/Tactical Air Navigation (VORTAC) and the Cranbrook, BC, Canada, VOR/Distance Measuring Equipment (VOR/DME), excluding the airspace with Canada. J-517 is unavailable to aircraft between the Boise and Spokane VORTACs unless they are equipped with a RNAV system with Global Positioning System (GPS) as annotated in Notice to Airmen FDC 5/7559 and FDC 5/7557. The route is subject to a service volume limitation issue with the Very High Frequency (VHF) signal due to terrain blocking the signal. Because of these issues, the FAA is proposing to revoke J-517 in its entirety and establish RNAV Route Q-151 as a replacement. Q-151 would extend between the WINEN, UT, waypoint (WP) and the EDGES, ID, Fix. The current EDGES Fix will be relocated and will replace the computer navigation fix, BZXIV, as a border coordination fix between the United States and Canada. Concurrently with this airspace action, NAV CANADA will revoke the remaining segment of J-517 within Canadian airspace and establish Q-151 between EDGES and the Cranbrook, BC, Canada, VOR/DME.

The FAA is proposing an amendment to 14 CFR part 71 by establishing RNAV Route Q-151 and revoking J-517 in its entirety.

J-517: Jet Route J-517 currently extends between the Boise, ID, VORTAC and the Cranbrook, BC, Canada, VOR/DME, excluding the airspace with Canada. J-517 is unavailable to aircraft between the Boise and Spokane VORTACs unless they are equipped with a RNAV system with GPS as annotated in Notice to Airmen FDC 5/7559 and FDC 5/7557. The FAA is proposing to revoke J-517 in its entirety and establish RNAV Route Q-151 as a replacement.

Q-151: The establishment of RNAV Q-151 is being proposed as a replacement for the loss of Jet Route J-517. Q-151 would extend between the WINEN, UT, WP and the EDGES, ID, Fix.

The FAA has determined that this proposed regulation only involves an established body of technical regulations for which frequent and routine amendments are necessary to keep them operationally current. It, therefore: (1) is not a “significant regulatory action” under Executive Order 12866; (2) is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034; February 26, 1979); and (3) does not warrant preparation of a regulatory evaluation as the anticipated impact is so minimal. Since this is a routine matter that will only affect air traffic procedures and air navigation, it is certified that this proposed rule, when promulgated, will not have a significant economic impact on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

This proposal will be subject to an environmental analysis in accordance with FAA Order 1050.1G, “FAA National Environmental Policy Act Implementing Procedures” prior to any FAA final regulatory action.

In consideration of the foregoing, the Federal Aviation Administration proposes to amend 14 CFR part 71 as follows:

SE 17th Street (Brooks Memorial) Bridge across the AICW, mile 1065.9, at Fort Lauderdale, FL, is a bascule bridge with a 55-foot vertical clearance at mean high water in the closed position. The normal operating schedule for the bridge is set forth in 33 CFR 117.261(bb)(8).

The City of Fort Lauderdale requested the Coast Guard consider additional opening restrictions during weekday rush hour periods to assist with vehicle congestion. The drawbridge currently opens twice an hour for navigation. This proposed change adds additional opening restrictions during weekday rush hour periods.

This NPRM will run simultaneously with a Test Deviation, under the same name and docket number. Both documents can be found at https://www.regulations.gov and comments can be made to either document.

The current operating schedule allows the SE 17th Street (Brooks Memorial) Bridge to open at the top and bottom of the hour for marine traffic. Under this proposed rule, the bascule bridge will open once an hour, at the top of the hour, Monday through Friday during pre-designated times. Vehicle traffic across the bridge is at or nearing roadway design capacity during certain times of the day. The Coast Guard is proposing to limit drawbridge openings during high vehicle traffic times to assist with vehicle congestion while requesting state and local agencies consider alternate mitigation measures to improve traffic flow and roadway congestion. The drawbridge will open twice an hour at all other times. The specific proposed operating schedule is this: The draw shall open on the hour and half-hour; except that from 6:50 a.m. to 9:10 a.m. and from 3:50 p.m. to 6:10 p.m., Monday through Friday, except Federal holidays, the drawbridge shall open once an hour at the top of the hour. Vessels that can pass beneath the bridge without an opening may do so at any time. Public vessels of the United States, tugs with tows and vessels in distress may pass any time.

In addition to the proposed change to the special requirement for the SE 17th Street (Brooks Memorial) Bridge, this proposed rule will republish section 117.261 to reorganize the paragraph structure to follow current regulatory drafting requirements. See paragraph (z) of the proposed regulatory text for the proposed operating schedule for the Brooks Memorial Bridge.

We developed this proposed rule after considering numerous statutes and Executive Orders related to rulemaking. Below we summarize our analyses based on these statutes and Executive Orders.

Executive Orders 12866 and 13563 direct agencies to assess the costs and benefits of available regulatory alternatives and, if regulation is necessary, to select regulatory approaches that maximize net benefits. This proposed rule has not been designated a “significant regulatory action,” under section 3(f) of Executive Order 12866. Accordingly, the NPRM has not been reviewed by the Office of Management and Budget (OMB).

This regulatory action determination is based on the ability that vessels can still transit the bridge during the designated times and vessels able to pass without an opening may do so at any time.

The Regulatory Flexibility Act of 1980 (RFA), 5 U.S.C. 601-612, as amended, requires Federal agencies to consider the potential impact of regulations on small entities during rulemaking. The term “small entities” comprises small businesses, not-for-profit organizations that are independently owned and operated and are not dominant in their fields, and governmental jurisdictions with populations of less than 50,000. The Coast Guard certifies under 5 U.S.C. 605(b) that this proposed rule would not have a significant economic impact on a substantial number of small entities.

While some owners or operators of vessels intending to transit the bridge may be small entities, for the reasons stated in section IV.A above this proposed rule would not have a significant economic impact on any vessel owner or operator.

If you think that your business, organization, or governmental jurisdiction qualifies as a small entity and that this rule would have a significant economic impact on it, please submit a comment (see ADDRESSES ) explaining why you think it qualifies and how and to what degree this rule would economically affect it.

Under section 213(a) of the Small Business Regulatory Enforcement Fairness Act of 1996 (Public Law 104-121), we want to assist small entities in understanding this proposed rule. If the proposed rule would affect your small business, organization, or governmental jurisdiction and you have questions concerning its provisions or options for compliance, please contact the person listed in the FOR FURTHER INFORMATION CONTACT section. The Coast Guard will not retaliate against small entities that question or complain about this proposed rule or any policy or action of the Coast Guard.

This proposed rule would call for no new collection of information under the Paperwork Reduction Act of 1995 (44 U.S.C. 3501-3520.).

A rule has implications for federalism under Executive Order 13132 (Federalism), if it has 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. We have analyzed this proposed rule under that Order and have determined that it is consistent with the fundamental federalism principles and preemption requirements described in Executive Order 13132.

Also, this proposed rule does not have tribal implications under Executive Order 13175 (Consultation and Coordination with Indian Tribal Governments) because it would not have a substantial direct effect on one or more Indian tribes, on the relationship between the Federal Government and Indian tribes, or on the distribution of power and responsibilities between the Federal Government and Indian tribes. If you believe this proposed rule has implications for federalism or Indian tribes, please contact the person listed in the FOR FURTHER INFORMATION CONTACT section.

The Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1531-1538) requires Federal agencies to assess the effects of their discretionary regulatory actions. In particular, the Act addresses actions that may result in the expenditure by a State, local, or tribal government, in the aggregate, or by the private sector of $100,000,000 (adjusted for inflation) or more in any one year. Though this proposed rule will not result in such an expenditure, we do discuss the effects of this proposed rule elsewhere in this preamble.

We have analyzed this rule under Department of Homeland Security Management Directive 023-01, Rev.1, associated implementing instructions, and Environmental Planning Policy COMDTINST 5090.1 (series), which guide the Coast Guard in complying with the National Environmental Policy Act of 1969 (NEPA)(42 U.S.C. 4321-4370f). The Coast Guard has determined that this action is one of a category of actions that do not individually or cumulatively have a significant effect on the human environment. This proposed rule promulgates the operating regulations or procedures for drawbridges. Normally such actions are categorically excluded from further review, under paragraph L49, of Appendix A, Table 1 of DHS Instruction Manual 023-01-001-01, Rev. 1.

Neither a Record of Environmental Consideration nor a Memorandum for the Record are required for this rule. We seek any comments or information that may lead to the discovery of a significant environmental impact from this proposed rule.

We view public participation as essential to effective rulemaking and will consider all comments and material received during the comment period. Your comment can help shape the outcome of this rulemaking. If you submit a comment, please include the docket number for this rulemaking, indicate the specific section of this document to which each comment applies, and provide a reason for each suggestion or recommendation.

Submitting comments. We encourage you to submit comments through the Federal Decision-Making Portal at https://www.regulations.gov. To do so, go to https://www.regulations.gov, type USCG-2025-0464 in the search box and click “Search.” Next, look for this document in the Search Results column, and click on it. Then click on the Comment option. If your material cannot be submitted using https://www.regulations.gov, contact the person in the FOR FURTHER INFORMATION CONTACT section of this document for alternate instructions.

Viewing material in docket. To view documents mentioned in this proposed rule as being available in the docket, find the docket as described in the previous paragraph, and then select “Supporting & Related Material” in the Document Type column. Public comments will also be placed in our online docket and can be viewed by following instructions on the https://www.regulations.gov Frequently Asked Questions web page. Also, if you go to the online docket and sign up for email alerts through the “Subscribe” option, you will be notified when comments/updates are posted, or a final rule is published.

We review all comments received, but we will only post comments that address the topic of the proposed rule. We may choose not to post off-topic, inappropriate, or duplicate comments that we receive.

Personal information. We accept anonymous comments. Comments we post to https://www.regulations.gov will include any personal information you have provided. For more about privacy and submissions in response to this document, see DHS's eRulemaking System of Records notice (85 FR 14226, March 11, 2020).

For the reasons discussed in the preamble, the Coast Guard proposes to amend 33 CFR part 117 as follows:

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 predominantly a secondary air pollutant created by 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 potential for ground-level ozone formation tends to be highest during months with warmer temperatures and stagnant air masses. Ozone levels are thus generally higher during the summer months, which is often referred to as “the ozone season.” In New York, the ozone season is generally considered to be between April 15 and October 15, while the non-ozone season is generally considered to be between October 16 and April 14.

A geographic area of the United States that is not meeting the primary or secondary National Ambient Air Quality Standard (NAAQS) for ozone is described as a nonattainment area. Nonattainment areas are classified as either Marginal, Moderate, Serious, Severe, or Extreme. With respect to this proposed action, there are two relevant ozone NAAQS standards. 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 (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 (2015 8-hour Ozone Standard). See 80 FR 65292 (October 26, 2015). Under CAA section 184, the State of New York is located within the Ozone Transport Region (OTR), which means that it is subject to statewide RACT requirements. This facility is not located in an ozone nonattainment area, but it is still required to implement RACT because it is located within the OTR.

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. CAA section 184(b)(2) sets forth the requirement to establish control measures to implement RACT for major sources of VOC located in the OTR. The State of New York is located within the OTR, and thus the State is required to implement RACT for all major sources of VOC within the State.

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. 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. The SSSIP should include the facility's RACT plan that demonstrates how the facility will implement RACT. The SSSIP will also include the applicable CAA operating permit conditions that address RACT requirements. These permit conditions for the Facility will become part of the Federally enforceable SIP upon the EPA's final approval of this SSSIP.

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. 2

This action relates to a SSSIP revision that concerns a web-based film coating machine for in-vitro diagnostics dry slide technology manufacturing operations. The source at issue in this action is for the Facility's pilot coating machine (the 72 Machine) for research and development of new potential products and material qualification experiments of non-compliant coatings. The 72 Machine also manufactures a small production run of equipment diagnostic calibration slides for internal purposes only. The 72 Machine is in total enclosure. The coating material is added to the process outside of the enclosed room and no workers are permitted to enter the enclosed room. To minimize VOC emissions, the overspray that can occur during coating operations is controlled using film manufacturing technology appropriate for the coating weight of the Ortho products. Generally, overspray can happen during a coating operation when the coating is applied onto a film substrate and if uncontrolled, overspray could generate excess VOC emissions. The 72 Machine's VOC exhaust is emitted via the roof vent.

The NYSDEC RACT regulations establish RACT requirements for this category of sources in 6 NYCRR part 228, “Surface Coating Processes, Commercial and Industrial Adhesives Sealants and Primers”, subpart 228-1, “Surface Coating Processes”, subpart 228-1.5, “Requirements for Controlling VOC Emissions Using Add-On Controls or Coating Systems,” last approved into New York's SIP by the EPA on March 4, 2014. See 79 FR 12082 (March 4, 2014). The coating machine meets the definition of a surface coating process under 6 NYCRR part 228-1 because it is a Class D coating line that applies solvent and aqueous based coatings to a polyethylene terephthalate substrate to produce testing slides. 3 However, as explained above, the NYSDEC RACT regulations allow source-specific RACT determinations if the presumptive RACT requirements are not technologically or economically feasible; such source-specific determinations must be submitted to the EPA as a SSSIP.

This SSSIP was submitted by NYSDEC on April 7, 2023. In this SSSIP submittal, the EPA has reviewed the RACT determination for 72 Machine for consistency with the CAA and the EPA regulations, as interpreted through EPA actions and guidance. The intended effect of this Source-specific SIP revision is to establish an emission limit for the process specific control measure for 72 Machine.

The EPA is proposing to determine through this SSSIP action that the VOC RACT emission limit submitted by the State in this SSSIP for 72 Machine is the lowest emission limit with the application of control technology that is reasonably available given technological and economic feasibility considerations. The respective VOC RACT emission limit is contained in the Facility's air permit, State Facility Permit, 8-2628-00503/02001, under Condition 13, issued by the State on October 31, 2022, and expires on October 30, 2032. The Condition 13 is being incorporated into the SIP and includes monitoring, reporting, and recordkeeping requirements for the proposed coating machine referred to as 72 Machine further described in EPA RACT Analysis below.

The Facility submitted a RACT demonstration, dated November 2021, to the NYSDEC for the emission limit requirements, and NYSDEC reviewed and approved the emission limit as adequately implementing RACT for the source. NYSDEC then submitted the source-specific SIP revision package at issue in this action for the EPA approval, and the EPA is proposing to determine the respective emission limit as implementing RACT for this source. The emission limit for the Facility will become part of the Federally enforceable SIP upon the EPA's final approval of this SSSIP.

The following is a summary of the EPA's analysis of how the proposed VOC emission limit implements RACT for the emission source 72 Machine. Further detail on this analysis is provided in the TSD available in the docket for this rulemaking. The Facility's coating machine, 72 Machine, is part of the coating line to produce testing slides. As described above, the 72 Machine is characterized as a surface coating process under subpart 228-1, “Surface Coating Processes”.

The RACT demonstration must show an alternate emission limit to comprise RACT and a RACT variance can be requested pursuant to 6 NYCRR subpart 228-1.5(e). Such a RACT variance can be approved if supported by a RACT demonstration and submitted to the EPA for review as a SIP revision.

The Facility's RACT demonstration shows that controlling the overspray is the only VOC control technology that is technologically and economically feasible for this facility, and that controlling the overspray ensures the VOC emissions will not exceed 21,600 pounds per year on a 12-month rolling total basis. Under 6 NYCRR subpart 228-1.5(e), NYSDEC may allow surface coating processes to operate with a lesser degree of control, as established in the applicable presumptive RACT requirements, provided that a process specific RACT demonstration satisfies NYSDEC's regulations, and it addresses technical and economic feasibility of utilizing compliant coatings. 4

NYSDEC reviewed the RACT demonstration and determined that the alternate emission limit implements RACT for the 72 Machine. Specifically, NYSDEC approved the following case-by-case emission limit: (1) Aggregate VOC emissions from non-compliant coatings A1c, 49CKMB, 90WHT, 92BLK on 72 Machine must not exceed 21,600 pounds per year on a 12-month rolling total basis; (2) ensure that non-compliant coatings A1c, 49CKMB, 90WHT, 92BLK have the same specifications as described in the November 2021 RACT demonstration; (3) track usage monthly and report compliance status on an annual basis; (4) failure to meet the pounds per year limit established for this RACT variance shall be ground for termination of the RACT variance; (5) a RACT variance evaluation must be reassessed every five years; and (6) an updated RACT variance request must be submitted by the facility for any changes that will increase the emission rate of 72 Machine, including but not limited to changes to coating specification, coating machine operation parameters, or coating curing/drying time.

We are proposing to determine that the following additional technically feasible control options do not need to be implemented because they are not cost effective: (1) thermal oxidation; (2) catalytic oxidation; and (3) ducting the VOC exhaust from 72 Machine to the Facility's other coating machine (71 Machine  5 ).

To determine what VOC control technologies could be economically and technologically feasible for the 72 Machine, the EPA reviewed the Reasonably Available Control Technology/Best Available Control Technology/Lowest Achievable Emission Rate Clearinghouse (RBLC)  6 and the vendor quotes provided by the State as part of the RACT evaluation. The EPA's RBLC search criteria were based on the process type “Paper, Plastic, and Foil Web Surface Coating.” The EPA's RBLC review reveals that there are three facilities in the United States that possibly operate with similar practices as 72 Machine: (1) Bemis Performance Packaging in Wisconsin manufactures flexible packing film and has a regenerative thermal oxidizer on a flexographic press machine; (2) American Packaging Corp in New York manufactures packaging material for the food industry and has a regenerative thermal oxidizer on a press machine; and (3) Benis in Indiana is a polyethylene film plant and has a cyrel plate making process with a catalytic and regenerative thermal oxidizer. The EPA also reviewed four vendor quotes for the thermal and catalytic oxidizers as contained in the SSSIP submission, and they appear to be technically sound. A vendor quote was not provided for ducting the emissions from 72 Machine to 71 Machine because ducting is not a reliable option due to the following: (1) ducting would involve complicated planning for coating schedules, and the two machines would not be able to operate at the same time due to incompatible static pressure between both machines, and (2) ducting emissions from 72 Machine to 71 Machine would result in overall airflow to exceed the design capacity of the existing catalytic oxidizer on 71 Machine. The EPA confirms that no cost-effective VOC control technologies have become available that could be implemented on the Facility's 72 Machine. Further detail on RBLC results and cost effectiveness are provided in the TSD available in docket for this rulemaking.

The EPA is proposing to determine that the proposed limit for 72 Machine implements RACT because: (1) The 6 NYCRR part 228-1 presumptive VOC limit for Class D coating line ( i.e., paper, film, and foil) of 0.08 pounds VOC per pound coating is not economically and technologically feasible for this source; (2) no additional control technologies beyond what are currently used at 72 Machine are technically and economically feasible; (3) emission limit of 21,600 pounds per year on a 12-month rolling total basis comprises RACT for this source; and (4) the SIP revision contains monitoring and reporting requirements.

The EPA is proposing to approve this source-specific revision because the limits included in the SSSIP implement RACT for 72 Machine. Based on information provided by NYSDEC, a thorough RBLC review of similar sources, and an analysis of this source-specific SIP revision, the EPA proposes to approve Ortho Clinical Diagnostics operation under the NYSDEC-approved VOC emission limit for the Facility's 72 Machine.

Specifically, the EPA proposes to determine the following SSSIP revision: (1) The aggregate VOC emissions from non-compliant coatings A1c, 49CKMB, 90WHT and 92BLK on 72 Machine must not exceed 21,600 pounds per year on a 12-month rolling total basis; (2) ensure that the non-compliant coatings have the same specifications as described in the RACT variance submitted November 2021; (3) track usage monthly and report compliance annually; (4) exceeding the 21,600 pounds per year limit shall be ground for termination of the RACT variance; (5) an updated RACT variance request must be submitted for any changes that will increase the emission rate, including but not limited to changes to coating specification, coating machine operation parameters, or coating curing/drying time; and (6) RACT must be reevaluated every 5 years and an updated RACT variance must be submitted every 5 years.

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 Ortho Clinical Diagnostics State Facility Permit condition 13 as described in section II of this preamble. The EPA has made, and will continue to make, these materials generally available through www.regulations.gov.

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, 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 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, “we,” “us,” and “our” refer to the EPA.

Table 1 lists the rules in the current SIP with the dates they were previously amended or revised by MDAQMD, submitted by the California Air Resources Board (CARB), the governor's designee for California SIP submittals, and approved by the EPA.

Table 2 lists the rules addressed by this proposal with the dates they were amended or revised by the MDAQMD and submitted by CARB, the agency that serves as the governor's designee for California SIP submittals.

On February 7, 2025, CARB's August 7, 2024 submittal (hereafter referred to as the “2024 Submittal”) for the MDAQMD was deemed complete by operation of law according to 40 CFR part 51, appendix V, which must be met before formal EPA review.

The 2024 Submittal is intended to address certain deficiencies identified by the EPA in the MDAQMD Rules 1301, 1302, 1303, 1304, and 1305 listed in table 1. The deficiencies pertain to certain applicable nonattainment NSR requirements under the CAA, in part D of title I of the Act, and the implementing regulations under 40 CFR 51.165. The nonattainment areas under the MDAQMD's jurisdiction are the San Bernardino County portion of the West Mojave Desert nonattainment area which is designated as a Severe nonattainment area for the 2008 and 2015 8-hour ozone NAAQS, and the Trona Planning Area in San Bernardino County which is designated as a Moderate nonattainment area for the 1987 PM 10 NAAQS. 40 CFR 81.305. The rules listed in table 2 are intended to replace the rules currently in the SIP as listed in table 1.

On November 25, 2022, the EPA proposed a limited approval/limited disapproval action for MDAQMD's Regulation XIII NSR Rules. 2 On June 30, 2023, the EPA finalized this limited approval/limited disapproval action (hereafter called the “2023 NSR Action”). 3 As authorized in sections 110(k)(3) and 301(a) of the Act, the EPA finalized a limited approval and limited disapproval of Rules 1301, 1302, 1303, 1304, and 1305 because although they fulfill most of the relevant CAA requirements and strengthen the SIP, they also contained six deficiencies that did not fully satisfy the relevant requirements for preconstruction review and permitting under section 110 and part D of title I of the Act. The deficiencies are described in the October 5, 2022 TSD for the action, as well as in the preambles to the November 25, 2022 proposed rule and the 2023 NSR Action. In addition, the EPA included the description of the six deficiencies in the preambles to the July 9, 2024 proposed rulemaking to promulgate a Federal Implementation Plan (“FIP”) in a portion of the MDAQMD to address the deficiencies identified in the 2023 NSR Action, 4 and in a December 30, 2024 rule (hereafter the “2024 NSR Action”)  5 finalizing the July 9, 2024 rulemaking and affirming the EPA's disapproval of Rule 1304(C)(2)(d) in response to the Ninth Circuit's remand of the 2023 NSR Action. 6 The TSD for this action provides more information on the MDAQMD's revisions for Rules 1301, 1302, 1303, 1304, and 1305 to address the deficiencies identified by the EPA. These deficiencies and the MDAQMD's revisions to address these deficiencies are summarized as follows.

The EPA determined that the use of the term “contract” as interchangeable with the term “permit” was deficient. Specifically, the MDAQMD Rules 1302(D)(6)(a)(iii) and 1304(C)(4)(c) allowed an owner and/or operator to obtain a valid permit or “contract” that would be enforceable by the District. The MDAQMD's rules define Authority to Construct Permit (ATC) and Permit to Operate (PTO), but do not define term “contract” as interchangeable with the term “permit.” The EPA found that the term “contract” was not an acceptable alternative to the term “permit” and thus the language in MDAQMD Rules 1302(D)(6)(a)(iii) and 1304(C)(4)(c) was not approvable as a SIP revision.

The EPA determined that the calculation procedures specified to determine the amount of offsets required in certain situations was deficient. Specifically, Rule 1304 allows a potential-to-potential test under certain circumstances for calculating the quantity of offsets required in some situations that involve the use of Simultaneous Emission Reductions (SERs) under 1304(C)(2)(d). This calculation procedure can also be used for calculation of required offsets for a “Modified Major Facility.” The EPA found that calculating emissions decreases using a potential emissions baseline allows reductions “on paper” that do not represent real emissions reductions and is not consistent with the requirements of CAA section 173(C)(1), as well as 40 CFR 51.165(a)(3)(i), (a)(3)(ii)(G), (a)(3)(ii)(J), and (a)(1)(vi)(C), to offset actual emissions increases. The deficiency identified in Rule 1304, through cross-references, also causes related deficiencies in Rules 1301, 1302, 1303, and 1305.

The EPA found that the definitions for “Major Modification” and “Modification (Modified)” pursuant to Rule 1301(NN) and 1301(JJ), respectively, were deficient. This deficiency is also related to Rule 1304(C)(2)(d) pertaining to the calculation of SERs. Specifically, a “Net Emissions Increase” pursuant to Rule 1304(B)(2) allows SERs “calculated and verified pursuant to [1304(C)(2)]” to be subtracted from the total of all “Net Emissions Increase” at any given facility. The EPA found that this can allow a permit applicant to avoid certain NSR requirements entirely ( i.e., lowest achievable emissions reduction (LAER), offsets, visibility, etc.). 7 Therefore, the EPA found that the District's calculation procedures for “Modification” and “Major Modification” were not consistent with the federal definition of “Major Modification” pursuant to 40 CFR 51.165(a)(1)(v)(A)(1); the calculation procedures for determining offsets pursuant to 40 CFR 51.165(a)(3)(ii)(J); and the criteria for determining the emission decreases that are creditable pursuant to 40 CFR 51.165(a)(1)(vi)(E)(1).

The EPA found that the definition of Historical Actual Emissions (HAE) pursuant to Rule 1304(D)(2)(a)(i) was deficient because of a typographical error that includes the word “proceeds” rather than “precedes.”

The EPA found that Rule 1305 section (C)(6) was deficient because it allowed the use of interprecursor trading between nonattainment pollutants and their precursors on a case-by-case basis for ozone, which is no longer allowed.

The EPA found that the District's NSR program was deficient because it did not satisfy the requirements in CAA sections 182(c)(6) and 182(d) that apply to severe ozone nonattainment areas.

The EPA has reviewed the revisions to the MDAQMD rules listed in table 2 for compliance with the following CAA requirements: (1) the general SIP requirements as set forth in CAA section 110(a)(2), including 110(a)(2)(A) and 110(a)(2)(E)(i); (2) the stationary source preconstruction permitting program requirements as set forth in CAA part D of title I, including CAA sections 171, 172(c)(5), 173, and 182; (3) the requirements for the review and modification of major sources in accordance with 40 CFR 51.160-51.165; (4) the requirements for the review of new major stationary sources or major modifications in a designated nonattainment area that may have an impact on visibility in any mandatory Class I federal area in accordance with 40 CFR 51.307; (5) the SIP revision requirements as set forth in CAA sections 110(l) and 193; and (6) the definition of “Stationary Source” in CAA section 302(z).

Sections 110(a)(2) and 110(l) of the Act require that each SIP or revision to a SIP submitted by the State must be adopted after reasonable notice and public hearing. In addition, section 110 of the Act requires that SIP rules be enforceable. Section 110(a)(2)(C) of the Act requires each SIP to include a program to regulate the modification and construction of any stationary source within the areas covered by the SIP as necessary to assure attainment and maintenance of the NAAQS. Section 110(a)(2)(E)(i) of the Act requires that each SIP provide necessary assurances that the state will have adequate personnel, funding, and authority under state (and, as appropriate, local) law to carry out such implementation plan.

Part D of title I of the Act contains certain definitions applicable to areas designated nonattainment for a NAAQS (section 171); the general requirements for permits for the construction and operation of new or modified major stationary sources anywhere in nonattainment areas referred to as nonattainment NSR (NNSR) (section 172); other additional preconstruction permit requirements for new or modified major stationary sources proposing to construct in nonattainment areas (section 173); and the de minimis SIP requirements in Severe nonattainment areas (sections 182(c)(6) and 182(d)).

The EPA's regulations at 40 CFR 51.160-51.164 provide general requirements to implement the statutory mandate under section 110(a)(2)(C) of the Act that is commonly referred to as the “general” or “minor” NSR program. These NSR program regulations impose requirements for approval of state and local programs that are more general in nature as compared to the specific statutory and regulatory requirements for NSR permitting programs under part D of title I of the Act.

The EPA's regulations at 40 CFR 51.165 set forth the EPA's regulatory requirements for SIP-approval of a nonattainment NSR permit program. Our review also evaluated the submittal for compliance with the NNSR requirements applicable to Severe ozone nonattainment areas and ensured that the submittal addressed the NNSR requirements for the 2015 ozone NAAQS.

The EPA's regulations at 40 CFR 51.307 set forth the protection of visibility requirements that apply to NSR programs. This provision requires that certain actions be taken in consultation with the local Federal Land Manager if a new major source or major modification may have an impact on visibility in any mandatory Federal Class I Area.

Section 110(l) of the Act prohibits the EPA from approving any SIP revisions that would interfere with any applicable requirement concerning attainment and reasonable further progress (RFP) or any other applicable requirement of the CAA.

Section 193 of the Act, which only applies in nonattainment areas, prohibits the modification of a SIP-approved control requirement in effect before November 15, 1990, in any manner unless the modification ensures equivalent or greater emissions reductions of such air pollutant.

Section 302(z) of the Act defines the term “Stationary Source” as generally any source of an air pollutant except those emissions resulting directly from an internal combustion engine for transportation purposes or from a nonroad engine or nonroad vehicle as defined in title II of the Act.

Our TSD, which can be found in the docket for this rule, contains a more detailed discussion of the approval criteria.

The EPA has reviewed the submitted rules in accordance with the rule evaluation criteria described above. With respect to procedural requirements, CAA sections 110(a)(2) and 110(l) require that revisions to a SIP be adopted by the state after reasonable notice and public hearing. According to the documentation provided in the 2024 Submittal, the state published public notices for announcing the public comment periods and public hearings in the Riverside Press Enterprise and in the San Bernardino Sun on February 22, 2024. Additionally, a public hearing was held on March 25, 2024. Based on our review of this information and the information that was provided in the 2024 Submittal, we find that there is sufficient evidence of public notice, and opportunities for comment and public hearing prior to adoption and submittal of these rules to the EPA.

With respect to substantive requirements, we have reviewed the submitted rules in table 1 in accordance with the evaluation criteria discussed above. We are proposing to conditionally approve the revisions to the MDAQMD's Rules 1301, 1302, 1303, 1304, and 1305 because, for the most part, they address the substantive statutory and regulatory requirements for NSR permit programs as contained in section II.B. of this document for the deficiencies identified by the EPA in the 2023 NSR Action. Rule 1304, however, contains a remaining deficiency; therefore, we are proposing conditional approval pursuant to CAA section 110(k)(4), on the basis of a commitment by CARB and the MDAQMD to revise Rule 1304 to correct the remaining deficiency within one year of the effective date of a final conditional approval action.

The following are brief descriptions of the revisions to MDAQMD's Rules 1301, 1302, 1303, 1304, and 1305 that address the deficiencies identified by the EPA in the 2023 NSR Action. Our TSD contains a more detailed discussion of our analysis of the submitted rules that form the basis for our proposed action.

In the 2023 NSR Action, the EPA determined that the use of the term “contract” in 1302(D)(6)(a)(iii) and 1304(C)(4)(c) is deficient because the term is used interchangeably with a permit ( i.e., an Authority to Construct (ATC) or a Permit to Operate (PTO)). However, MDAQMD's NSR rules do not define the term “contract” or provide requirements for how a contract is an enforceable mechanism that may be used in the same way as an ATC or PTO. The MDAQMD clarified in the comments it submitted on EPA's November 2022 proposed rulemaking action that the term “contract” appears to be superfluous because of requirements elsewhere in its rules and that the retention of the term was inadvertent. The MDAQMD stated in that same comment letter that it would remove the term “contract” from the rule provisions the EPA identified.

In the 2024 Submittal, the MDAQMD revised Rule 1304(C) by removing the term “contract” from Rule 1304(C)(4)(c). The MDAQMD also removed the reference to Net Emissions Increase from Rule 1304(C)(5). Therefore, MDAQMD's revision of 1304(C) corrects the deficiency in 1304(C) concerning the term “contract.” The MDAQMD neglected to remove the term “contract” from Rule 1302(D)(6)(a)(iii), but given the explanation it provided in its comments to the EPA's 2022 proposed rulemaking and the revision it made to Rule 1304(C) indicate MDAQMD's interpretation of the term “contract” is consistent with federal requirements, the EPA is recategorizing the inclusion of the term “contract” in Rule 1302(D)(6)(a)(iii) from a deficiency to a recommendation for further improvement in future revisions to Rule 1302.

In the 2023 NNSR Action, the EPA determined that Rule 1304(C)(2)(d) was deficient because it allows the use of a potential-to-emit (PTE)-to-PTE calculation procedure for calculating the quantity of “Simultaneous Emission Reductions” (SERs) that can be used as offsets at a “Modified Major Facility.” The EPA determined that Rule 1304(C)(2)(d), in certain situations, does not comply with CAA section 173(c)(1), 40 CFR 51.165(a)(3)(i), (a)(3)(ii)(G), (a)(3)(ii)(J), and (a)(1)(vi)(E). Additionally, because either Rule 1304(C) or Rule 1304(C)(2)(d) is referenced in Rules 1301, 1302, 1303, and 1305, the EPA also determined that these referenced rules are deficient. In a letter dated June 12, 2025 (“June 12, 2025 Commitment Letter”) the MDAQMD committed to revising Rule 1304 to add a provision to rescind section (C)(2)(d) such that it will no longer be in effect 24 months after the effective date of the EPA's final approval of the revised Rule 1304 into the SIP. The June 12, 2025 Commitment Letter also includes MDAQMD's commitment to transmit its revised rule to CARB in time for CARB to submit the rule to the EPA within 12 months of the publication of a final conditional approval by the EPA. 8 Relatedly, in a letter from CARB dated June 17, 2025 (“June 17, 2025 Commitment Letter”), CARB also commits to submit the rule to the EPA within 12 months of the publication of a final conditional approval by EPA. 9

Section 110(k)(4) of the Act allows the EPA to conditionally approve a SIP revision based on a commitment from the State to adopt and submit specific, enforceable measures to correct the identified deficiency no later than one year after the date of approval of the plan revision. The MDAQMD has committed to adopt and submit, within the one-year timeframe specified in section 110(k)(4), a revised rule that would add a provision to rescind Rule 1304 section (C)(2)(d) 24 months after the effective date of the EPA's final approval of the revised rule. Because the inclusion of Rule 1304(C)(2)(d) in the MDAQMD's NNSR program is the deficiency pertaining to offset requirements identified in the 2023 NSR Action, rescission of section (C)(2)(d) of Rule 1304 would correct the deficiency concerning offsets identified in the 2023 NSR Action. As explained further below, we find the 24-month sunsetting period proposed by the MDAQMD to be justified by the particular circumstances surrounding the MDAQMD's NNSR program and the District's need for time to reassess its emissions reduction credit (ERC) banking reserves for compliance with federal offset requirements. 10 The EPA's conditional approval, if finalized, would trigger the 1-year timeframe under CAA section 110(k)(4) for the MDAQMD to revise and submit Rule 1304 consistent with the MDAQMD's commitment. If EPA subsequently approves the revised Rule 1304 into the SIP, that action would provide the basis for the EPA to terminate the Federal Implementation Plan (FIP) that is currently in place in the MDAQMD, under section 110(c)(1) of the Act. 11

The MDAQMD's overhaul of the offsets calculations portion of its NNSR program, which has been in effect since at least 1995, requires the District to reconfigure its ERC banking system to conform to federal requirements, which the MDAQMD has committed to implement. The MDAQMD has represented that it faces a significant administrative burden in reconfiguring its ERC bank to comply with federal requirements. 12 The 24-month period following the approval of MDAQMD's revised Rule 1304 and simultaneous termination of the NNSR FIP that is currently in effect in the MDAQMD is unlikely to interfere with attainment or reasonable further progress in the MDAQMD. 13 Thus, the EPA is proposing to conditionally approve the MDAQMD's 2024 Submittal based on the MDAQMD's commitment to revise Rule 1304 to add a provision to rescind section (C)(2)(d) in its entirety, effective 24 months after the EPA's final approval of the revised Rule 1304 into the SIP. The June 12, 2025 and June 17, 2025 Commitment Letters detail revisions that are clear and enforceable, correct the identified deficiencies, and fulfill CAA requirements for a conditional approval. If the EPA finalizes the proposed conditional approval and the MDAQMD and CARB submit a revised Rule 1304 that rescinds section (C)(2)(d) as described in the June 12, 2025 and June 17, 2025 Commitment Letters, the EPA will propose to fully approve Rule 1304, as revised, into the California SIP.

The EPA's TSD for this action describes how the MDAQMD's revision to Rule 1304 would correct the related deficiencies in Rules 1301, 1302, 1303, and 1305. The cross references to section (C) in Rule 1304 in those rules render them deficient because of the deficiency in Rule 1304(C)(2)(d), but MDAQMD's revision to rescind section (C)(2)(d) would immediately correct these deficiencies without the need for revisions to any other provisions in the other MDAQMD Regulation XIII rules. If either the MDAQMD or CARB fails to adopt and submit these amendments within the required timeframe, CAA section 110(k)(4) specifies that the conditional approval of Rule 1304 shall be treated as a disapproval.

In the 2023 NSR Action, the EPA determined that Rule 1301(JJ) (Definition for “Major Modification”) and Rule 1301(NN) (Definition of “Modification (Modified)”) are deficient because they are inconsistent with the federal definition for Major Modification pursuant to 40 CFR 51.165(a)(1)(v)(A)(1), 14 and the calculation procedures for determining offsets pursuant to 40 CFR 51.165(a)(3)(ii)(J) and CAA section 173(c)(1) and 40 CFR 51.165(a)(1)(vi)(E)(1). The EPA also determined that the use of calculation procedures in 1304(B)(2) does not conform to the calculation procedures for determining offsets pursuant to CAA section 173(c)(1) and 40 CFR 51.165(a)(3)(ii)(J) and the criteria for determining the emissions decreases that are creditable pursuant to 40 CFR 51.165(a)(1)(vi)(E)(1). The MDAQMD amended Rules 1301(JJ) (Definition of “Major Modification”), 1301(NN) (Definition of “Modification (Modified)”), 1301(NNN) (Definition of “Significant”), and 1301(QQ) (Definition of “Net Emissions Increase”) to remove the references to “Net Emissions Increase” to resolve the deficiencies previously identified by the EPA such that these requirements are no longer deficient. The MDAQMD also removed the “Net Emissions Increase” calculations that were in Rule 1304(B)(2) and changed the definition of this term in Rule 1301(QQ) to address the deficiency previously identified by the EPA. These revisions address the deficiencies previously identified by the EPA concerning NSR applicability.

In the 2023 NSR Action, the EPA determined that the HAE procedures in Rule 1304(D)(2) are deficient because of a typographical error in which the word “precedes” is used rather than “proceeds.” The MDAQMD revised Rule 1304 by correcting the typographical error in (D)(2)(a)(i), changing the word “proceeds” to “precedes.” This revision addresses the deficiency previously identified by the EPA.

In the 2023 NSR Action, the EPA determined that Rule 1305(C)(6) is deficient because it allows interpollutant trading for ozone precursors on a case-by-case basis, which is no longer allowed under 40 CFR 51.165. The MDAQMD revised Rule 1305(C)(6) by removing the interprecursor trading provisions. This revision resolves the deficiency that the EPA previously identified.

In the 2023 NSR Action, the EPA determined that the MDAQMD's NSR rules do not contain the de minimis plan requirements for ozone nonattainment areas contained in CAA sections 182(c)(6) and 182(d) that apply to areas classified as Severe nonattainment. The MDAQMD amended Rule 1303 to include the de minimis plan requirements. Specifically, the MDAQMD's revisions to Rule 1303(A), which are included in the 2024 Submittal, ensure that facilities with PTE above thresholds in Rule 1303(B)(1) must install BACT at any new or modified permit unit. 15 Rule 1303(B) requires facilities with PTE greater than the threshold levels stated in Rule 1303(B)(1) to obtain offsets. The MDAQMD's revision addresses the deficiency previously identified by the EPA.

The EPA is proposing conditional approval of MDAQMD Rules 1301, 1302, 1303, 1304, and 1305 as authorized in section 110(k)(4) of the Act. Section 110(k)(4) of the Act states that the Administrator may approve a plan revision based on a commitment of the State to adopt specific enforceable measures by a date certain, but not later than one year after the date of approval of the plan revision. It further states that any such conditional approval shall be treated as a disapproval if the State fails to comply with such commitment. The June 12, 2025 and June 17, 2025 Letters contain commitments by MDAQMD and CARB to correct the deficiency pertaining to Rule 1304(C)(2)(d) identified in the 2023 NSR Action, as described in this proposed action, and submit the revised Rule 1304 to EPA within one year of EPA's final conditional approval, in accordance with section 110(k)(4) of the Act. Therefore, as authorized in section 110(k)(4) of the CAA, the EPA proposes to conditionally approve the submitted rules based on the commitment by the State to adopt and submit revisions to Rule 1304(C)(2)(d) by a date certain but not later than one year after the effective date of the conditional approval. If this proposed conditional approval is finalized as proposed, and the MDAQMD or CARB fails to comply with this commitment, the conditional approval would be treated as a disapproval.

The EPA is proposing to find that our action, if finalized, would result in a more stringent SIP and is consistent with the additional substantive requirements of CAA sections 110(l) and 193, while not relaxing any existing provision contained in the SIP, and will not interfere with any applicable attainment and reasonable further progress requirements or any other applicable CAA requirement. With specific regard to MDAQMD's commitment to revise Rule 1304 to include a provision that would rescind section (C)(2)(d) and its consistency with section 110(l) of the Act, the EPA in this rulemaking action is proposing to conditionally approve the 2024 Submittal on the basis of the June 12, 2025 and June 17, 2025 Letters, which commit the MDAQMD and CARB to adopt and submit revisions to Rule 1304 that would add provisions to rescind section (C)(2)(d) 24 months after the effective date of the EPA's full approval of Rule 1304. Rescission of Rule 1304(C)(2)(d) is SIP strengthening, but the 24-month period between the EPA's approval of the revised Rule 1304 into the SIP and simultaneous termination of the FIP means that Rule 1304(C)(2)(d), which is deficient for the reasons provided in the 2023 NSR Action and 2024 NSR Action, would be in effect for that 24-month period before the District implements the revised Rule 1304. For the reasons described in section II.D.2. of this document, the EPA is proposing to find this short delay in the District's compliance with federal NNSR offset requirements justified as a matter of administrative necessity in light of the MDAQMD's need to reassess and revise the ERC banking reserves implemented as part of its NNSR program.

For the deficiencies described in this document, which relate to NNSR requirements under part D of title I of the Act, the offset sanction in CAA section 179(b)(2) became effective in the nonattainment areas at issue on January 31, 2024, 16 and the highway funding sanctions in CAA section 179(b)(1) will become effective on July 31, 2025. 17 As a separate action in this Federal Register , we are making an interim final determination that will stay or defer the imposition of CAA sanctions associated with our previous limited disapproval action.

If we finalize this action as proposed, our action conditionally approving Rules 1301, 1302, 1303, 1304, and 1305 will be codified through revisions to 40 CFR 52.220 (Identification of plan—in part) and 40 CFR 52.248 (Identification of plan—conditional approval). If CARB or the MDAQMD fail to comply with this commitment, the conditional approval would convert to a disapproval. We will accept comments from the public on this proposal until August 25, 2025. If we take final action to approve the submitted rules, our final action will incorporate these rules into the federally enforceable SIP.

In this document, 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 the MDAQMD rules described in table 2 of this preamble. The EPA has made, and will continue to make, these materials available through https://www.regulations.gov and in hard copy at the EPA Region IX 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 Act and applicable federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the Act. Accordingly, this proposed action merely proposes to approve state law as meeting federal requirements and does not impose additional requirements beyond those imposed by state law. For that reason, this proposed action:

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

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

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

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

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

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

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

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

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

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

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

On May 13, 2020, the Texas Commission on Environmental Quality (TCEQ or State) submitted to EPA a SIP revision addressing RACT requirements for the 2008 8-hour ozone NAAQS for the two Serious ozone nonattainment areas in Texas—the Dallas-Fort Worth (DFW) and HGB areas. 1 EPA proposed approval of the portions of the submittal that addressed VOC and NO X RACT requirements for the HGB area on March 10, 2021. For background information regarding the HGB area, Texas' May 13, 2020, SIP submittal, the ozone NAAQS, and RACT, please see the EPA's original proposal for this action at 86 FR 13679 (March 10, 2021). In this supplemental proposal, we refer to the May 13, 2020, Texas SIP revision as “the RACT submittal” and we refer to our March 10, 2021, proposed action and Technical Support Document (TSD) as “the March 2021 proposal.” We are supplementing the March 2021 proposal with respect to VOC RACT. We will address NO X RACT in a separate action.

In our March 2021 proposal, we proposed to approve the RACT submittal for the HGB nonattainment area as meeting the VOC RACT requirements for an area designated as Serious with the exception of the requirement to implement RACT for sources covered by the 2016 CTG for the Oil and Natural Gas Industry. 2 We proposed to determine that the Texas rules implemented RACT ( i.e., the lowest achievable emission rate considering technical and economic feasibility) for all sources subject to all remaining CTG categories. In addition, we proposed that the Texas rules also implement RACT for major sources in categories not covered by a CTG (non-CTG RACT). 3 We also proposed to approve negative declarations made for fiberglass boat manufacturing materials, manufacturing of pneumatic rubber tires, flat wood paneling coatings, letterpress printing, and automobile and light-duty truck assembly coatings sectors in the HGB area.

During EPA's public comment period, we received a comment claiming that our proposed action would approve a state submission that relied on outdated RACT determinations. EPA has since reviewed additional information and conducted additional analysis. We are providing this supplemental proposal, and an associated Supplemental TSD, containing a compendium of EPA's review of relevant rules (from a variety of other states) currently in place to implement VOC RACT for CTG covered sources across the country. Based on our review of these state rules, and in comparison to Texas' May 13, 2020 SIP submission, we confirm our previous proposal that Texas' rules meet RACT requirements for the 2008 ozone NAAQS.

EPA performed an analysis which can be found in the Supplemental TSD  4 evaluating the relevant RACT rules in various states including Arizona, California, Colorado, Illinois, Indiana, Maine, New Hampshire, Ohio, Vermont, and Wisconsin. EPA found Texas' rules to be generally consistent with or more stringent than control measures in other states' regulations and CTGs. In addition, we reviewed the EPA's RACT/BACT/LAER clearinghouse database, which contains case-specific information on the best available air pollution control technologies that have been required to reduce the emission of air pollutants from stationary sources. 5 EPA has not identified any new control technologies that are reasonably available considering technological and economic feasibility for these sources. Based upon our findings, EPA confirms our previous proposal that Texas VOC RACT regulations are still representative of RACT for the HGB nonattainment area for the purpose of the 2008 ozone NAAQS standard.

The EPA is supplementing our March 2021 proposal addressing revisions to the Texas SIP with respect to the VOC RACT requirements for the HGB Serious nonattainment area for the 2008 ozone NAAQS. In this supplemental proposal, we are providing an opportunity for public comment on EPA's VOC RACT analysis that further supports the March 2021 proposed approval record in showing that Texas VOC RACT regulations do implement RACT level controls, consistent with sections 182(b)(2) and (c) of the CAA. The EPA will address all comments received on our March 2021 proposal and on this supplemental proposal in our final action.

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, 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 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.

The EPA is proposing to approve the regional haze SIP revision submitted by the Washington Department of Ecology (Ecology) on January 28, 2022, under the CAA and the EPA's Regional Haze Rule for the program's second implementation period. Washington's SIP submission addresses the requirement that States must periodically revise their long-term strategies for making reasonable progress towards the national goal of preventing any future, and remedying any existing, anthropogenic impairment of visibility, including regional haze, in mandatory Class I Federal areas. The SIP submission also addresses other applicable requirements for the second implementation period of the regional haze program. The EPA is taking this action pursuant to CAA sections 110 and 169A.

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 Regional Haze Rule (RHR) revisions, please refer to Section III of this publication. Overview of Visibility Protection Statutory Authority, Regulation, and Implementation of “Protection of Visibility: Amendments to Requirements for State Plans” of the 2017 RHR. 2 The following is an abbreviated history and background of the regional haze program and 2017 RHR as it applies to the current action.

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. 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).

In CAA section 169A(a)(1), Congress established the national goal of preventing any future and remedying any existing impairment of visibility in mandatory Class I Federal areas that results from manmade (anthropogenic) air pollution. The core component of a regional haze SIP submission for the second planning period is a strategy that addresses regional haze in each Class I area within the State's borders and each Class I area outside the State that may be affected by emissions originating from within the State, CAA section 169A(b)(2)(B), 40 CFR 51.308(f)(2), and makes “reasonable progress” toward the national goal based on consideration of the four statutory factors in CAA section 169A(g)(1)—the costs of compliance, the time necessary for compliance, the energy and non-air quality environmental impacts of compliance, and the remaining useful life of any potentially affected sources. 3

Regional haze is visibility impairment that is produced by a multitude of anthropogenic sources and activities which are located across a broad geographic area and that emit pollutants that impair visibility. Visibility impairing pollutants include fine and coarse particulate matter (PM) ( e.g., sulfates, nitrates, organic carbon, elemental carbon, and soil dust) and their precursors ( e.g., sulfur dioxide (SO 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 35714, July 1, 1999, at page 35768).

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).

The Western Regional Air Partnership (WRAP)  5 is one of five regional air quality planning organizations across the United States. 6 The WRAP functions as a voluntary partnership of State, Tribal, Federal, and Local air agencies whose purpose is to understand current and evolving air quality issues in the west. There are 15 member States, including Washington, and 28 Tribal and 30 Local air agency members. 7 Federal partners include the EPA, National Park Service, U.S. Fish and Wildlife Service, Forest Service, and Bureau of Land Management.

Based on emissions and monitoring data supplied by its membership, the WRAP produced technical tools to support modeling of visibility impacts at Class I areas across the west. 8 The WRAP Technical Support System for the second implementation period or “TSSV2” consolidated air quality monitoring data, meteorological and receptor modeling data analyses, emissions inventories and projections, and gridded air quality/visibility regional modeling results. The TSSV2 is accessible by members and allows for the creation of maps, figures, and tables to export and use in developing regional haze plans and maintains the original source data for verification and further analysis. 9

On January 28, 2022, Ecology submitted a revision to the Washington SIP to address regional haze for the second planning period. Ecology made this SIP submission to satisfy the requirements of the CAA's regional haze program pursuant to CAA sections 169A and 169B and 40 Code of Federal Regulations (CFR) 51.308.

Under the CAA and EPA's regulations, all 50 States, the District of Columbia, and the U.S. Virgin Islands are required to submit regional haze SIPs satisfying the applicable requirements for the second implementation period of the regional haze program by July 31, 2021. Each State's SIP must contain a long-term strategy for making reasonable progress toward meeting the national goal of remedying any existing and preventing any future anthropogenic visibility impairment in Class I areas. CAA 169A(b)(2)(B). To this end, 40 CFR 51.308(f) lays out the process by which States determine what constitutes their long-term strategies, with the order of the requirements in 40 CFR 51.308(f)(1) through (3) generally mirroring the order of the steps in the reasonable progress analysis  10 and (f)(4) through (6) containing additional, related requirements.

Broadly speaking, a State first must identify the Class I areas within the State and determine the Class I areas outside the State in which visibility may be affected by emissions from the State. These are the Class I areas that must be addressed in the State's long-term strategy. See 40 CFR 51.308(f), (f)(2). For each Class I area within its borders, a State must then calculate the baseline (five-year average period of 2000-2004), current, and natural visibility conditions ( i.e., visibility conditions without anthropogenic visibility impairment) for that area, as well as the visibility improvement made to date and the “uniform rate of progress” (URP).

The URP is the linear rate of progress needed to attain natural visibility conditions, assuming a starting point of baseline visibility conditions in 2004 and ending with natural conditions in 2064. This linear interpolation is used as a tracking metric to help States assess the amount of progress they are making towards the national visibility goal over time in each Class I area. See 40 CFR 51.308(f)(1). Each State having a Class I area and/or emissions that may affect visibility in a Class I area must then develop a long-term strategy that includes the enforceable emission limitations, compliance schedules, and other measures that are necessary to make reasonable progress in such areas. A reasonable progress determination is based on applying the four factors in CAA section 169A(g)(1) to sources of visibility impairing pollutants that the State has selected to assess for controls for the second implementation period. Additionally, as further explained below, the RHR at 40 CFR 51.3108(f)(2)(iv) separately provides five “additional factors”  11 that States must consider in developing their long-term strategies. See 40 CFR 51.308(f)(2).

A State evaluates potential emission reduction measures for those selected sources and determines which are necessary to make reasonable progress. Those measures are then incorporated into the State's long-term strategy. After a State has developed its long-term strategy, it then establishes 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) and (3). There are additional requirements in the rule, including (Federal Land Manager) FLM consultation, that apply to all visibility protection SIPs and SIP revisions. See e.g., 40 CFR 51.308(i).

In addition to satisfying the requirements at 40 CFR 51.308(f) related to reasonable progress, the regional haze SIP revisions for the second implementation period must address the requirements in 40 CFR 51.308(g)(1) through (5) pertaining to periodic reports describing progress towards the RPGs, 40 CFR 51.308(f)(5), as well as requirements for FLM consultation that apply to all visibility protection SIPs and SIP revisions. See e.g., 40 CFR 51.308(i).

A State must submit its regional haze SIP and subsequent SIP revisions to the EPA according to the requirements applicable to all SIP revisions under the CAA and the EPA's regulations. See CAA section 169A(b)(2); CAA section 110(a). Upon approval by the EPA, a SIP is enforceable by the Agency and the public under the CAA. If the EPA finds that a State fails to make a required SIP revision, or if the EPA finds that a State's SIP is incomplete or if it disapproves the SIP, the Agency must promulgate a Federal implementation plan (FIP) that satisfies the applicable requirements. CAA section 110(c)(1).

The first step in developing a regional haze SIP is for a State to determine which Class I areas, in addition to those within its borders, “may be affected” by emissions from within the State. In the 1999 RHR, the EPA determined that all States contribute to visibility impairment in at least one Class I area, 64 FR 35714, July 1, 1999, at pages 35720-22, and explained that the statute and regulations lay out an “extremely low triggering threshold” for determining “whether States should be required to engage in air quality planning and analysis as a prerequisite to determining the need for control of emissions from sources within their State.” Id. at 35721.

A State must determine which Class I areas must be addressed by its SIP by evaluating the total emissions of visibility impairing pollutants from all sources within the State The determination of which Class I areas may be affected by a State's emissions is subject to the requirement in 40 CFR 51.308(f)(2)(iii) to “document the technical basis, including modeling, monitoring, cost, engineering, and emissions information, on which the State is relying to determine the emission reduction measures that are necessary to make reasonable progress in each mandatory Class I Federal area it affects.”

As part of assessing whether a SIP submission for the second implementation period is providing for reasonable progress towards the national visibility goal, the RHR contains requirements in 40 CFR 51.308(f)(1) related to tracking visibility improvement over time. The requirements of this section apply only to States having Class I areas within their borders; the required calculations must be made for each such Class I area. The EPA's 2018 Visibility Tracking Guidance provides recommendations to assist States in satisfying their obligations under 40 CFR 51.308(f)(1); specifically, in developing information on baseline, current, and natural visibility conditions, and in making optional adjustments to the URP to account for the impacts of international anthropogenic emissions and prescribed fires. See 82 FR 3078, January 10, 2017, at pages 3103-05.

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

Using the data for the set of most impaired days only, States must plot a line between visibility conditions in the baseline period and natural visibility conditions for each Class I area to determine the URP—the amount of visibility improvement, measured in deciviews, that would need to be achieved during each implementation period to achieve natural visibility conditions by the end of 2064. The URP is used in later steps of the reasonable progress analysis for informational purposes and to provide a non-enforceable benchmark against which to assess a Class I area's rate of visibility improvement. Additionally, in the 2017 RHR Revisions, the EPA provided States the option of proposing to adjust the endpoint of the URP to account for impacts of anthropogenic sources outside the United States and/or impacts of certain types of wildland prescribed fires. These adjustments, which must be approved by the EPA, are intended to avoid any perception that States should compensate for impacts from international anthropogenic sources and to give States the flexibility to determine that limiting the use of wildland-prescribed fire is not necessary for reasonable progress. 82 FR 3078, January 10, 2017, at page 3107, footnote 116.

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

The core component of a regional haze SIP submission is a long-term strategy that addresses regional haze in each Class I area within a State's borders and each Class I area outside the State that may be affected by emissions from the State. The long-term strategy “must include the enforceable emissions limitations, compliance schedules, and other measures that are necessary to make reasonable progress, as determined pursuant to (f)(2)(i) through (iv).” 40 CFR 51.308(f)(2). The amount of progress that is “reasonable progress” is based on applying the four statutory factors in CAA section 169A(g)(1) in an evaluation of potential control options for sources of visibility impairing pollutants, which is referred to as a “four-factor” analysis. The outcome of that analysis is the emission reduction measures that a particular source or group of sources needs to implement to make reasonable progress towards the national visibility goal. See 40 CFR 51.308(f)(2)(i). Emission reduction measures that are necessary to make reasonable progress may be either new, additional control measures for a source, or they may be the existing emission reduction measures that a source is already implementing. See 82 FR 3078, 3092-93. Such measures must be represented by “enforceable emissions limitations, compliance schedules, and other measures” ( i.e., any additional compliance tools) in a State's long-term strategy in its SIP. 40 CFR 51.308(f)(2).

The regulation at 40 CFR 51.308(f)(2)(i) provides the requirements for the four-factor analysis. The first step of this analysis entails selecting the sources to be evaluated for emission reduction measures; to this end, the RHR requires States to consider “major and minor stationary sources or groups of sources, mobile sources, and area sources” of visibility impairing pollutants for potential four-factor control analysis. 40 CFR 51.308(f)(2)(i). A threshold question at this step is which visibility impairing pollutants will be analyzed.

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. 12 This is accomplished by considering the four factors—“the costs of compliance, the time necessary for compliance, and the energy and non-air quality environmental impacts of compliance, and the remaining useful life of any existing source subject to such requirements.” CAA section 169A(g)(1). The EPA has explained that the four-factor analysis is an assessment of potential emission reduction measures ( i.e., control options) for sources: “use of the terms `compliance' and `subject to such requirements' in section 169A(g)(1) strongly indicates that Congress intended the relevant determination to be the requirements with which sources would have to comply to satisfy the CAA's reasonable progress mandate.” 82 FR 3091 (January 10, 2017). Thus, for each source it has selected for four-factor analysis, 13 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. 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. 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 51.308(f)(2)(iv) separately provides five “additional factors”  14 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).

In this proposed action, the EPA notes that it is the Agency's policy, as announced in the EPA's recent approval of the West Virginia Regional Haze SIP, 15 that where the State has considered the four statutory factors, and visibility conditions for a Class I area impacted by a State are projected to be below the URP in 2028, the State has presumptively demonstrated reasonable progress for the second implementation period for that area. The EPA acknowledges that this proposed action reflects a change in policy as to how the URP should be used in the evaluation of regional haze second planning period SIPs. However, the EPA finds that this policy aligns with the purpose of the statute and RHR, which is achieving “reasonable” progress, not maximal progress, toward Congress' natural visibility goal.

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 3091 (January 10, 2017). 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 section apply either to States with Class I areas within their borders, States with no Class I areas but that are reasonably anticipated to cause or contribute to visibility impairment in any Class I area, or both. Compliance with the monitoring strategy requirement may be met through a State's participation in the Interagency Monitoring of Protected Visual Environments (IMPROVE) monitoring network, which is used to measure visibility impairment caused by air pollution at the 156 Class I areas covered by the visibility program. 40 CFR 51.308(f)(6), (f)(6)(i) and (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) and (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 3119, January 10, 2017). To this end, every State's SIP revision for the second implementation period is required to assess changes in visibility conditions and describe the status of implementation of all measures included in the State's long-term strategy, including Best Available Retrofit Technology (BART) and reasonable progress emission reduction measures from the first implementation period, and the resulting emissions reductions. 40 CFR 51.308(g)(1) and (2).

CAA section 169A(d) requires that before a State holds a public hearing on a proposed regional haze SIP revision, it must consult with the appropriate FLM or FLMs; pursuant to that consultation, the State must include a summary of the FLMs' conclusions and recommendations in the notice to the public. Consistent with this statutory requirement, the RHR also requires that States “provide the [FLM] with an opportunity for consultation, in person and at a point early enough in the State's policy analyses of its long-term strategy emission reduction obligation so that information and recommendations provided by the [FLM] can meaningfully inform the State's decisions on the long-term strategy.” 40 CFR 51.308(i)(2). For 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).

Washington submitted its regional haze SIP for the first implementation period (2008 through 2018) on December 22, 2010, and submitted a supplemental SIP submission on December 29, 2011. The Clean Air Act and 40 CFR 51.308(d) and (e) required that the initial round of regional haze plans include, among other things, a long-term strategy for making reasonable progress and best available retrofit technology requirements for certain older stationary sources, where applicable. The EPA partially approved and partially disapproved Washington's first implementation period SIP submission on June 11, 2014 (79 FR 33438), issuing FIPs codified at 40 CFR 52.2500 Best available retrofit technology (BART) requirements for the Intalco Aluminum Corporation (Intalco Works) primary aluminum plant—Better than BART Alternative, 40 CFR 52.2501 Best available retrofit technology requirement for the Tesoro Refining and Marketing Company oil refinery—Better than BART Alternative, and 40 CFR 52.2502 Best available retrofit technology requirements for the Alcoa Inc.—Wenatchee Works primary aluminum smelter to remedy the disapproved elements.

Subsequently, on November 6, 2017, Washington submitted a five-year progress report, and the EPA approved the progress report on July 31, 2018 (83 FR 36752). In the action to approve the progress report, the EPA determined that the Washington regional haze plan for the first implementation period was adequate and required no substantive revision.

On January 28, 2022, Washington submitted its regional haze plan for the second implementation period (2018 through 2028). 16 Washington made its January 28, 2022, submission available for public comment on October 19, 2021 through November 23, 2021  17 and held a public hearing on November 18, 2021. 18 The State received and responded to public comments and included the comments and comment responses in the SIP submission. 19

The following sections of this document describe the Washington submission, including but not limited to air quality modeling conducted, source selection and control measure analysis, assessment of progress made since the first implementation period in reducing emissions of visibility impairing pollutants, and the visibility improvement progress at Class I areas in Washington and other States impacted by Washington sources. This document also contains the EPA's evaluation of the Washington submission against the requirements of the Clean Air Act and Regional Haze Rule 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.

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 35714, July 1, 1999, at page 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.

Washington has eight designated Class I areas, including three national parks and five wilderness areas. 20

Olympic National Park includes a significant portion of the Olympic Peninsula in northwestern Washington. It consists of two segments: the Olympic Mountains, which form the mountainous core of the park, and a coastal strip, stretching for 90 kilometers (km) (56 miles (mi)) along the Pacific coast. Thirteen major rivers flow from the Olympic Mountains in all directions.

North Cascades National Park is set in the rugged mountains of the Cascade Mountain Range in northcentral Washington, about 80 km (50 mi) east of Bellingham. The area was set aside to preserve dramatic mountain scenery, alpine areas, and glaciers. Mountain summits rise abruptly 1,800-2,600 meters (m) (5,900-8,530 feet (ft)) above the valley floor.

Mount Rainier National Park became the nation's fifth national park in 1899. One hundred km (62 mi) southeast of Seattle, Mount Rainier is the highest of the chain of volcanoes comprising the Cascade Range. At 4,392 meters (m) (14,410 feet (ft)), Mount Rainier is the fifth tallest peak in the contiguous 48 States. The massive mountain occupies more than one-fourth of the park's area. The 27 major glaciers on its slopes form the largest mass of year-round ice in the United States outside of Alaska.

Glacier Peak Wilderness includes more than 200 lakes, many unnamed and tremendously difficult to access, in various cirques and hidden basins. The wilderness straddles the northern Cascade Range roughly between the Suiattle River on the west and Lake Chelan on the east. Glacier Peak Wilderness is bordered to the North by North Cascades National Park.

When Congress passed the 1976 Alpine Lakes Wilderness Act to protect the area in its unique natural state, it created the Alpine Lakes Wilderness. The name Alpine Lakes takes its origin from the nearly 700 small mountain lakes nestled among the high rock peaks and forested valleys of the region. The Mt. Baker-Snoqualmie National Forest and the Okanogan-Wenatchee National Forest jointly administer the wilderness.

The Goat Rocks Wilderness is a portion of the volcanic Cascade Range in southwestern Washington located between Mount Rainier and Mount Adams. The Goat Rocks are remnants of a large volcano, which has been extinct for some two million years. The cluster of rocks and peaks in this area earned the title “Goat Rocks” because of the bands of mountain goats that live there. The wilderness lies in both the Gifford Pinchot National and the Okanogan-Wenatchee National Forests.

Congress designated the Mount Adams Wilderness in 1964. The wilderness lies in the Gifford Pinchot National Forest on the crest of the Cascade Range in southwestern Washington. Second in height only to Mount Rainier statewide, 3,742 m (12,276 ft) Mount Adams looms over at least 10 glaciers and a wilderness of forested slopes and subalpine meadows. The volcanic bulk of the mountain takes up a considerable portion of the Wilderness.

The Pasayten Wilderness stretches across the crest of the Cascade Range in northern Washington. The wilderness is bordered on the north by 80 km (50 mi) of the Canadian border and on the west by the Ross Lake National Recreation Area. The Pasayten Wilderness is in both the Okanogan-Wenatchee and the Mount Baker-Snoqualmie National Forests.

Haze species in Washington are measured and analyzed via the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. 21 Table 1 of this document lists the IMPROVE air quality monitors representing visibility at Washington Class I areas. Due to the remote nature of the Class I areas, some areas share a common IMPROVE station.

Ecology reviewed Particulate Matter Source Apportionment Technology (PSAT) modeling conducted by the WRAP to determine potential visibility impacts from Washington sources on Class I areas in other States. 22 Chapter 6.8 Other Mandatory Class 1 Areas Impacted by Washington Anthropogenic Emissions of Washington's submission identifies all out-of-State IMPROVE stations where Washington anthropogenic sources are expected to contribute at least 0.1% of the nitrate or sulfate light extinction, based on the WRAP modeling results. Ecology further refined the analysis to focus on significant contribution, defined as a 5% or greater contribution of light extinction from nitrates or sulfates on the most impaired days, identifying impacted Montana and Oregon Class I areas. Specifically, these areas in Montana were the Cabinet Mountains Wilderness, Glacier National Park, Bob Marshall Wilderness Area, Mission Mountain Wilderness Area, Scapegoat Wilderness Area, Anaconda-Pintler Wilderness Area, and Selway-Bitterroot Wilderness Area. In Oregon these areas were the Kalmiopsis Wilderness, Mt. Hood Wilderness, Strawberry Mountain Wilderness, Eagle Cap Wilderness, Mt. Jefferson Wilderness, Mt. Washington Wilderness, and Three Sisters Wilderness. As discussed in section IV.E of this document with respect to Washington's long-term strategy, Ecology focused its planning efforts on improving visibility at Class I areas in Washington for three primary reasons: (1) for SO 2 , those sources that significantly impact Class I areas in other States have either closed or are subject to existing SIP requirements, (2) for NO X , the vast majority of modeled impact to out of State Class I areas is from the mobile source sector already addressed by controls in place, and (3) Washington did not receive any requests for reductions from neighboring States during State-to-State consultations. 23

Washington's January 28, 2022, SIP revision satisfies the requirements of 40 CFR 51.308(f)(2), related to the identification of Class I areas outside of Washington that may be affected by emissions from within the State and consultation with affected States.

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).

The Washington submission addresses baseline, current and natural visibility conditions for each of the IMPROVE stations as required by the 2017 Regional Haze Rule and the EPA's technical guidance on tracking visibility progress. Ecology reviewed visibility data from 2000 through 2018 and determined that current visibility at all Class I areas for both the clearest and most impaired days had improved since the baseline period, satisfying the Regional Haze Rule requirement of no degradation in visibility for the clearest days since the baseline period. In addition, all areas met the 2018 URP for the most impaired days as shown in Table 2 of this document. Additionally, most areas, including Olympic National Park, North Cascades National Park, Glacier Peak Wilderness, Mount Rainier National Park, Goat Rocks Wilderness, and Mount Adams Wilderness, have already met the projected 2028 URP for the most impaired days based on 2014 through 2018 monitoring data.

In accordance with 40 CFR 51.308(f)(1)(vi), Washington used modeling performed by the WRAP to adjust the URP for certain international anthropogenic sulfate impacts on the most impaired days. As noted in Chapter 9.1 of Washington's submission, “Washington's Class 1 areas are all affected by international anthropogenic contributions that Washington cannot control. Source apportionment results (Chapter 6) show that sulfates from international anthropogenic sources are expected to impact visibility more than in-State sources at all Washington Class 1 areas. Source apportionment results also show that nitrates from international anthropogenic sources are expected to impact visibility more than in-State sources at most Washington Class 1 areas, with the exception of Alpine Lakes Wilderness Area and Mount Rainier National Park.” Washington further explained that the methodology used by the WRAP to adjust the glidepath was consistent with methods described in the EPA's September 2019 regional haze modeling Technical Support Document included in the docket for this action. The EPA reviewed the 2028 URP adjustments and 2064 glidepath endpoints calculated by WRAP and confirmed that the values were similar to, but slightly lower than the corresponding 2028 URP adjustments and 2064 glidepath endpoints calculated by the EPA in our 2019 regional haze modeling Technical Support Document (Table 5-2 and Appendix E, respectively). Lastly, Washington did not adjust the glidepath to account for the impacts of wildland prescribed fires.

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

Under the CAA, EPA promulgated an 8-hour ozone standard of 0.075 parts per million (ppm) in 2008, which is more protective than the previous 1997 8-hour ozone standard (73 FR 16436, March 27, 2008). 1 On May 21, 2012, EPA published in the Federal Register the initial designations and classifications for the 2008 8-hour ozone standard (77 FR 30088). The DFW 10-county area (Collin, Dallas, Denton, Ellis, Johnson, Kaufman, Parker, Rockwall, Tarrant, and Wise counties)  2 was initially classified as Moderate nonattainment for the 2008 ozone NAAQS. Id. at 30147. On August 23, 2019, the EPA reclassified the DFW NAA from Moderate to Serious for the 2008 8-hour ozone NAAQS (84 FR 44238, August 23, 2019). 3 Under its Serious classification, pursuant to CAA sections 182(c) and 182(f), Texas must ensure NO X RACT is in place for all major sources (50 tpy or greater) of NO X in the DFW NAA.

Section 172(c)(1) of the CAA requires that SIPs for nonattainment areas “provide for the implementation of all reasonably available control measures as expeditiously as practicable (including such reductions in emissions from existing sources in the area as may be obtained through the adoption, at a minimum, of reasonably available control technology) and shall provide for attainment of the primary National Ambient Air Quality Standards (NAAQS).” The EPA has interpreted this to mean that RACT is the lowest emissions limitation that a particular source is capable of meeting by the application of control technology that is reasonably available, considering technological and economic feasibility. 4 Section 182 of the CAA requires that states must ensure RACT is in place for each source category for which EPA has issued a control techniques guidelines (CTG), and for any major source not covered by a CTG. CAA section 182(c) defines “major stationary source” as one that emits or has the potential to emit 50 tons per year (tpy) or more of NO X . EPA issues CTGs and each CTG describes techniques available for reducing emissions of VOC from a category of sources, and states recommended levels of control. 5 EPA also issues Alternative Control Techniques (ACTs) for NO X . ACTs provide information on available control technologies and their respective cost effectiveness at the time the ACT was issued. ACTs provide information related to control of both major and minor sources, but states are only required to provide for RACT at major sources of NO X .

In 2015, EPA published the final SIP Requirements Rule (SRR) for implementing the 2008 8-hour ozone NAAQS (80 FR 12279, March 6, 2015). EPA described in the SRR an approach “. . . allowing in some cases for states to conclude that sources already addressed by RACT determinations for the 1-hour and/or the 1997 ozone NAAQS do not need to implement additional controls to meet the 2008 ozone NAAQS RACT requirement” and noted that “in some cases, a new RACT determination would result in the same or similar control technology under the 1-hour or 1997 standard because fundamental control techniques, as described in the CTGs and ACTs, are still applicable.” Importantly, EPA stated that while states should refer to the existing CTGs and ACTs for purposes of informing their RACT requirements, in doing an updated assessment of RACT for the nonattainment the state should also refer to “. . . all relevant information (including recent technical information and information received during the public comment period) that is available at the time that they are developing their RACT SIPs for the 2008 ozone NAAQS.”

On May 12, 2020, TCEQ submitted to EPA a SIP revision to 30 TAC Chapter 117 to implement the major source RACT requirements for NO X associated with its Serious classification for the 2008 ozone NAAQS. TCEQ also submitted to EPA on May 13, 2020, the DFW Serious area AD SIP revision that included a RACT demonstration and analysis for NO X , a negative declaration for the nitric or adipic acid manufacturing category of emission sources, and a discussion of cement kilns operating in the nonattainment area.

On May 12, 2020, the EPA received the TCEQ's submitted rule revisions to 30 TAC Chapter 117 “Control of Air Pollution from Nitrogen Oxides”. The proposed revisions revise 30 TAC Chapter 117 to amend the definition of the DFW NAA to include Wise County and extend the implementation of Serious area RACT to new major sources of NO X in the DFW NAA, including Wise County. 6 In EPA's action reclassifying the DFW NAA as Serious for the 2008 8-hour ozone NAAQS, Wise County was reclassified from Moderate to Serious nonattainment. 80 FR 44238 (August 23, 2019). The State revised Chapter 117 to implement RACT requirements for all major sources of NO X in all ten counties of the DFW Serious ozone NAA as required by CAA sections 172(c)(1), 182(c), and 182(f). The new Serious major source levels are set at 50 tpy for the DFW NAA in these rule changes. The Chapter 117 changes ensure major sources of NO X emissions in Wise County are now subject to RACT requirements under the Serious classification.

The TCEQ analysis for NO X sources in the DFW NAA can be found in Chapter 4 of the AD, Section 4.5.2 (RACT Analysis, NO X RACT Determination), and Appendix F (Reasonably Available Control Technology Analysis) of the May 13, 2020, SIP submittal. A copy of Appendix F is also included in the docket to our action.

TCEQ reviewed the EPA's ACT documents to identify potential source categories of NO X emissions. TCEQ also reviewed the point source emissions inventory and Title V databases to identify all major sources of NO X emissions. TCEQ's assessment included sources that reported actual emissions as low as 25 tpy of NO X to account for the difference between actual and potential emissions.

For the source category “Nitric and Adipic Acid Manufacturing”, Texas stated that there no existing nitric or adipic acid manufacturing plants in the DFW NAA area. TCEQ also stated that for sites with cement kilns in Ellis County, no sites have used wet kilns since 2015, having replaced higher-emitting wet kilns with dry kilns.

A detailed analysis is provided in the Technical Support Document (TSD) for this action and other supporting documents are available in the docket for this action.

EPA has reviewed the proposed RACT analysis in the AD, appendix F, and the proposed and final record provided by TCEQ for Chapter 117 rule revisions which includes explanations and determinations on NO X control technologies, economic and technical feasibility, and NO X emissions reductions expected. In addition, EPA examined recent relevant technical information, including best available control technology (BACT) determinations, recent documents issued by the EPA that contained information on the performance of NO X control technologies, resulting emissions reductions, and other state rules to compare to Texas' SIP submittal and in other states where similar source categories exist in NAAs. 7 These documents are identified in the TSD and are available in the public docket to this action.

EPA finds that a comparison of Texas' NO X emissions rates to other state's rates, recent BACT determinations, and the Texas rulemaking and AD records provide sufficient justification that the control technologies included in the previously approved Chapter 117 rules continue to comprise RACT level of control for the DFW nonattainment area for the 2008 ozone NAAQS.

The EPA is proposing to determine that the SIP revisions submitted by TCEQ on May 12, 2020, and May 13, 2020, fulfill the Serious RACT requirements for the DFW nonattainment area for the 2008 ozone NAAQS. The EPA is also proposing to approve the concurrent Chapter 117 rule revisions.

Under the CAA, the Administrator is required to approve a SIP submission that complies with the provisions of the Act and applicable Federal regulations. 42 U.S.C. 7410(k); 40 CFR 52.02(a). Thus, in reviewing SIP submissions, the EPA's role is to approve state choices, provided that they meet the criteria of the 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 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 proposed 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 June 22, 2010, the EPA revised the primary SO 2 NAAQS, establishing a new 1-hour primary standard of 75 parts per billion (ppb). 1 Under the EPA's regulations at title 40 of the Code of Federal Regulations (CFR) part 50, the 2010 1-hour SO 2 NAAQS is met at a monitoring site when the design value  2 is less than or equal to 75 ppb (based on the rounding convention in 40 CFR part 50, appendix T). 3 Ambient air quality monitoring data for the 3-year period must meet a data completeness requirement. A year meets data completeness requirements when all four quarters are complete, and a quarter is complete when at least 75 percent of the sampling days in the quarter have complete data. A sampling day has complete data if 75 percent of the hourly concentration values, including State-flagged data affected by exceptional events which have been approved for exclusion by the Administrator, are reported. 4

Upon promulgation of a new or revised NAAQS, the CAA requires the EPA to designate as nonattainment any area that does not meet (or that contributes to ambient air quality in a nearby area that does not meet) the NAAQS. 5 On August 5, 2013, the EPA designated a portion of Beaver County, Pennsylvania (hereafter the “Beaver County NAA”), as nonattainment for the 2010 1-hour primary SO 2 NAAQS, effective October 4, 2013. 6 The designation was based on violating air quality monitoring data for calendar years 2009-2011. The Beaver County NAA consists of 6 municipalities including: Industry Borough, Shippingport Borough, Midland Borough, Brighton Township, Potter Township, and Vanport Township. 7 This action established an attainment date five years after the effective date for the areas designated as nonattainment for the 2010 SO 2 NAAQS ( i.e., by October 4, 2018). The Commonwealth was also required to submit an attainment plan SIP revision for the Beaver County NAA to the EPA that met the requirements of CAA sections 110, 172(c) and 191-192 within 18 months of the October 4, 2013, effective date of designation ( i.e., by April 4, 2015).

The EPA did not receive an attainment plan SIP revision for the Beaver County NAA by the April 4, 2015 deadline and subsequently on March 18, 2016, the EPA published a finding of failure to submit indicating that Pennsylvania did not submit the required SO 2 attainment plan. 8 This finding initiated a clock under CAA section 179(a) for the potential imposition of new source review sanctions 18 months after the effective date of the finding and the potential imposition of highway funding sanctions 6 months following that, in accordance with CAA section 179(b) and 40 CFR 52.31. Additionally, under CAA section 110(c), the finding triggered a requirement for the EPA to promulgate a Federal implementation plan (FIP) within two years of the effective date of the finding unless, by that time, Pennsylvania made the necessary complete submittal, and the EPA approved the submittal.

Ultimately, Pennsylvania did submit an attainment plan SIP revision on September 29, 2017. The EPA issued an October 5, 2017 letter to Pennsylvania finding the attainment plan submittal complete and noting the stopping of the sanctions' deadline. As a result, these CAA section 179(b) sanctions were not imposed. 9 The EPA proposed approving the attainment plan SIP revision submittal on October 5, 2018, 10 and issued a final approval on October 1, 2019. 11 This approval ended the requirement for the EPA to promulgate a FIP under CAA section 110(c).

Relevant to this action, on August 12, 2024, PADEP submitted a revision to its SIP for the inclusion of a maintenance plan for the 2010 1-hour primary SO 2 NAAQS and requested a concurrent redesignation of the Beaver County NAA to attainment for the 2010 1-hour primary SO 2 NAAQS. 12

After a State has submitted a redesignation request for a nonattainment area, the EPA must assess if the statutory criteria identified in CAA section 107(d)(3)(E) have been met to redesignate the area to attainment. These conditions include: (1) the EPA has determined that the applicable NAAQS has been attained; (2) the applicable SIP has been fully approved by the EPA under CAA section 110(k); (3) the EPA has determined that the improvement in the area's air quality is due to permanent and enforceable reductions in emissions; (4) the area has a fully approved maintenance plan, including a contingency plan, under CAA section 175A; and (5) the State has met all applicable requirements for the area under CAA section 110 and part D. The EPA has provided direction for how it would consider if these conditions have been met in the April 23, 2014 memorandum “Guidance for 1-Hour SO 2 Nonattainment Area SIP Submissions” (2014 SO 2 Guidance). 13

CAA section 175A and additional EPA guidance, including the September 4, 1992 memorandum “Procedures for Processing Requests to Redesignate Areas to Attainment” (Calcagni Memo), 14 identify the required elements for an approvable maintenance plan for areas seeking redesignation from nonattainment to attainment. Under CAA section 175A, the plan must demonstrate continued attainment of the applicable NAAQS for at least 10 years after the EPA approves a redesignation request to attainment. Eight years after the redesignation, the State must submit a revised maintenance plan demonstrating that attainment will continue to be maintained for an additional 10 years following the initial 10-year period. To address the possibility of future NAAQS violations, the maintenance plan must contain contingency measures, as the EPA deems necessary, to assure prompt correction of any future NAAQS violations, in this case the 2010 1-hour SO 2 NAAQS. The Calcagni Memo provides further guidance on the content of a maintenance plan, explaining that a maintenance plan should address five requirements: (1) an attainment emissions inventory that identifies the level of emissions in the area which is sufficient to attain the NAAQS; (2) a maintenance demonstration that shows future emissions of a pollutant will not exceed the level of the attainment inventory; (3) the continued operation of a monitoring network that conforms to 40 CFR part 58; (4) a means for verifying the continued attainment of the NAAQS; and (5) a contingency plan to correct any violation of the NAAQS in the area following redesignation of the area.

The EPA's evaluation of Pennsylvania's redesignation request and maintenance plan for the Beaver County NAA is based on consideration of the five redesignation criteria provided under CAA section 107(d)(3)(E) and relevant guidance, including the aforementioned 2014 SO 2 Guidance and Calcagni Memo.

CAA section 107(d)(3)(E)(i) requires that the EPA determine that a nonattainment area has attained the applicable NAAQS in order to redesignate the area to attainment. In assessing if the area has attained the NAAQS, the 2014 SO 2 Guidance stipulates that the EPA can interdependently consider two components to support an attainment determination: air quality monitoring data and air quality modeling data. 15

The Beaver County NAA contains one operational SO 2 monitor site, located in Brighton Township (Air Quality System (AQS) Site ID 42-007-0005). The Brighton monitor has been in operation since 1994 when active SO 2 sources and emissions within the area were substantially different than current conditions, due to facility shutdowns in more recent years. Since the 2013-2015 period, the Brighton monitor has been in attainment of the 2010 1-hour primary SO 2 NAAQS with the most recent design value for the 2021-2023 period measuring 5 parts per billion (ppb), though this design value did not meet data completeness requirements. Previously, PADEP also operated a second SO 2 monitor in the vicinity of the Beaver NAA. The Hookstown monitor (AQS Site ID 42-007-0002) was located approximately 4.5 miles southwest of the edge of the Beaver NAA and was in operation from 1983 until 2022. The Hookstown monitor was in attainment of the 2010 1-hour primary SO 2 NAAQS since the 2010-2012 period with the most recent design value for the 2020-2022 period measuring 11 ppb, though this design value did not meet data completeness requirements. Design values for both the Brighton and Hookstown monitors are reported in Table 1 in this document.

Pennsylvania's 2017 attainment plan contained an attainment demonstration which utilized allowable SO 2 emission limits from stationary sources within the Beaver County NAA to inform several modeling analyses for SO 2 emissions. 16 These modeling analyses were based on emissions limits for large, stationary sources of SO 2 , which, when enacted, would ensure that the Beaver County NAA would attain the 2010 1-hour primary SO 2 NAAQS. The 2014 SO 2 Guidance states that the EPA may make a determination of attainment based on this attainment plan modeling, eliminating the need for separate actual emissions-based modeling to support a redesignation request—provided that the source characteristics are still reasonably represented and that the control strategy in the SIP has been fully implemented. 17

Since Pennsylvania's 2017 submittal of this attainment plan modeling—which EPA approved in 2019 (84 FR 51988, October 1, 2019)—operations at large, stationary SO 2 sources within the Beaver County NAA have changed, but the EPA has determined that source characteristics are reasonably represented. Specifically, the 2019 closure of the Bruce Mansfield facility has reduced SO 2 emissions within the Beaver County NAA by approximately 4,427 tons per year from 2018 levels. Conversely, the Shell ethane cracker, which utilized an emission rate of 21 tons per year in the attainment plan modeling, was permitted an increased emission limit of 22.4 tons per year—though, it should be recognized that the Shell facility has not emitted greater than 1 ton of SO 2 per year since coming online. Despite these changes, the source characteristics are still reasonably represented as the closure of the Bruce Mansfield facility leads to a modeled overestimation of actual operations of SO 2 sources within the Beaver County NAA and the 1.4 ton per year increase to the Shell ethane cracker permitted limit is negligible in the context of the approximately 4,427 ton per year reduction from the Bruce Mansfield closure.

The 2014 SO 2 Guidance further states that a demonstration that the control strategy in the SIP has been fully implemented will also be pertinent for making the determination of attainment. 18 Pennsylvania has submitted information detailed in its redesignation request and maintenance plan to confirm that the control strategy outlined in the SIP has been fully implemented. Specific measures identified in the control strategy include emissions restrictions at the Bruce Mansfield facility and reactivation restrictions at the Allegheny and Tsingshan Stainless Acquisition Melt Shop, which was shut down in 2018. 19 As the Bruce Mansfield facility has closed and the Allegheny and Tsingshan Stainless Melt Shop facility has since been permanently removed from service, these facilities are in compliance with the proposed control strategy. 20 These implemented permanent and federally enforceable control measures have aided in reducing the actual total emissions from large, stationary SO 2 sources in the Beaver County NAA to 4,539 tons per year (as of 2018), 21 which is well below the revised total emissions limits proposed for Beaver County NAA facilities in the 2017 attainment demonstration modeling (32,420 tons per year), 22 thus contributing to bringing the Beaver County NAA into attainment. The closure of the Bruce Mansfield facility in 2019 led to an additional reduction of approximately 4,427 tons of SO 2 from 2018 levels, bringing current total SO 2 emissions in the Beaver County NAA closer to approximately 100 tons per year.

As the source characteristics within the Beaver County NAA are still reasonably represented and the control strategy in the SIP has been fully implemented, the EPA may make a determination of attainment based on this attainment plan modeling. In this action, the EPA proposes to find that the air quality modeling data demonstrate that the Beaver County NAA has attained the 2010 1-hour primary SO 2 NAAQS, with the air quality monitoring data further supporting this conclusion.

CAA section 107(d)(3)(E)(ii) requires that the EPA fully approve the applicable implementation plan for the area under CAA section 110(k) in order to redesignate that area to attainment. An area cannot be redesignated to attainment if a required element of the SIP is the subject of a disapproval; a finding of failure to submit, or failure to implement the SIP; or a partial, conditional, or limited approval. 23 The 2017 attainment plan SIP was initially proposed for EPA approval on October 5, 2018  24 and received final EPA approval on October 1, 2019. 25 The approved elements from the 2017 attainment plan include a 2011 base year emissions inventory, a control strategy and air quality modeling demonstration, a reasonable available control measures/reasonably available control technology (RACM/RACT) analysis, a reasonable further progress (RFP) analysis, contingency measures, and nonattainment new source review (NNSR) regulations. As such, the EPA has fully approved the applicable Pennsylvania SIP for the Beaver County NAA under section 110(k) of the CAA for all requirements applicable for purposes of redesignation.

For redesignating a nonattainment area to attainment, CAA section 107(d)(3)(E)(iii) requires the EPA to determine that the air quality improvement in the area is due to permanent and enforceable reductions in emissions resulting from implementation of the SIP, applicable Federal air pollution control regulations, and other permanent and enforceable reductions. The EPA proposes to find that Pennsylvania has demonstrated that the requirements of CAA section 107(d)(3)(E)(iii) have been met.

Specifically, the closures of multiple facilities aided in a substantial decrease in SO 2 emissions, and consequently, lower SO 2 concentrations in the Beaver County NAA. These closures include the following shutdowns: the Horsehead/Monaca Smelter in 2013, the AES Beaver Valley facility in 2015, the Allegheny and Tsingshan Stainless Melt Shop in 2018, and the Bruce Mansfield facility in 2019. 26 Collectively, these closures account for a reduction of approximately 26,458 tons of SO 2 emitted per year from 2011 levels. 27 The Calcagni Memo states that “[e]mission reductions from source shutdowns can be considered permanent and enforceable to the extent that those shutdowns have been reflected in the SIP and all applicable permits have been modified accordingly,” and therefore these shutdowns are considered permanent and enforceable. 28 Furthermore, the recently constructed Shell ethane cracker and the nearby IPSCO Koppel facility have had SO 2 emissions limits included in their operating permits to preserve air quality improvements in the Beaver County NAA. 29

Collectively, facility closures and the permitted SO 2 emissions rates resulted in an actual decrease of approximately 22,052 tons of SO 2 emitted per year from 2011 to 2018. This is approximately an 83% reduction from 2011 levels of 26,622 tons of SO 2 emitted per year. 30 As this reduction comes from facility closures and permit-controlled emission limits, the EPA proposes to find the air quality improvement in the Beaver County NAA to be due to permanent and enforceable reductions in emissions.

To redesignate a NAA to attainment, CAA section 107(d)(3)(E)(iv) requires the EPA to determine that the area has a fully approved maintenance plan pursuant to section 175A of the CAA. In conjunction with its request to redesignate the Beaver County NAA to attainment for the 2010 1-hour primary SO 2 NAAQS, the State submitted a SIP revision to provide for the maintenance of the 2010 1-hour primary SO 2 NAAQS for at least 10 years after the effective date of redesignation to attainment. The EPA is proposing to find that this maintenance plan meets the requirements for approval under section 175A of the CAA.

CAA section 175A sets forth the elements of a maintenance plan. Under section 175A, the plan must demonstrate continued attainment of the applicable NAAQS for at least 10 years after the Administrator approves a redesignation request to attainment. Eight years after the redesignation, the State must submit a revised maintenance plan demonstrating that attainment will continue to be maintained for an additional 10 years following the initial 10-year period. To address the possibility of future NAAQS violations, the maintenance plan must contain contingency measures as the EPA deems necessary to assure prompt correction of any future NAAQS violations, here the 2010 1-hour primary SO 2 NAAQS. As noted above, the Calcagni Memo provides further guidance on the content of a maintenance plan, explaining that a maintenance plan should address five requirements: (1) the attainment emissions inventory; (2) maintenance demonstration; (3) monitoring; (4) verification of continued attainment; and (5) a contingency plan. 31 As discussed in detail below, the EPA is proposing to determine that Pennsylvania's submitted maintenance plan meets the requirements in CAA section 175A and is thus proposing to approve it as a revision to the Beaver County portion of the Pennsylvania SIP.

In a maintenance plan, states are required to submit an emissions inventory to identify the level of emissions in the area which is sufficient to attain and maintain the relevant NAAQS, which is called the attainment inventory. This inventory is used as the basis for future, projected emission inventories that are used to show the area will remain in attainment. Pennsylvania submitted a 2018 SO 2 emissions inventory as the attainment inventory with its maintenance plan. This represented a year in which SO 2 emissions were at levels required to demonstrate attainment of the 2010 SO 2 NAAQS.

For the 2018 attainment year inventory, Pennsylvania directly used point source emissions reported to Pennsylvania for 2018, except for the Heritage Valley Beaver heliport, 32 which was projected from the 2017 National Emission Inventory (NEI). 33 The point source emissions for the Beaver County NAA were verified against the EPA's emissions inventory system (EIS) and the EPA found them to be acceptable. Projected emissions for area sources in 2018 were estimated from the 2017 NEI emission data and growth factors developed by the Mid-Atlantic Regional Air Management Association (MARAMA), Inc. These growth factors are developed based on forecasts from various databases and tools, including the Energy Information Administration's 2019 and 2020 Annual Energy Outlook, the 2016 NEI Collaborative data for the rail and the oil and gas Source Classification Codes, and other sources that are detailed in the submitted maintenance plan. 34 Area source emissions were estimated based on the relative percentage of the Beaver County population residing in the Beaver County NAA and the resulting factor allocated the appropriate fraction of the County's total emissions to the Beaver County NAA.

Nonroad and onroad mobile source emissions for 2017 were obtained from the EPA's Motor Vehicle Emissions Simulator (MOVES) model, specifically the MOVES2014b version. PADEP executed the MOVES2014b modeling runs for nonroad mobile sources and utilized a contractor to run the model for onroad mobile source emissions.

Projected inventories from the attainment inventory demonstrate that the area will continue to remain in attainment throughout the first maintenance period. Pennsylvania developed 2028 and 2036 emission projections for the interim and maintenance plan end year, respectively. Projected emissions for these years—as well as the base year inventory—are available in Table 2 in this document. Projected emissions for point and area sources were estimated, as previously described for area sources, from the 2017 NEI and growth factors developed by MARAMA. Point sources that have shut down since the 2018 base year were excluded from the 2028 and 2036 projections, namely the Bruce Mansfield facility. Nonroad and onroad mobile source emissions for the projected years 2028 and 2036 were estimated from the MOVES2014b version. MOVES2014b modeling runs were once again executed by PADEP for nonroad mobile source emissions and by the contractor for onroad mobile source emissions. Additional details on some of the assumptions and inputs to the model are available in the redesignation request and its associated Appendices C5 and C6. 35

On September 7, 2016, in response to separate petitions  1 from the American Trucking Associations (ATA) and Schneider National, Inc. et al. (including 9 other ATA-member motor carriers), NHTSA and FMCSA issued a joint NPRM proposing to require heavy vehicles with a GVWR of more than 11,793 kilograms (26,000 pounds) be equipped with a speed limiting device initially set to a speed no greater than a speed to be specified in a final rule. NHTSA and FMCSA also proposed to require motor carriers operating such vehicles in interstate commerce to maintain the speed limiting devices for the service life of the vehicle (81 FR 61942). NHTSA and FMCSA requested comment on speeds ranging from 60 to 68 miles per hour (mph). The estimated economic impacts of the joint NPRM varied widely based upon the set speed, with annual costs ranging from $209 million to $1.561 billion. The Agencies also estimated that, at a 65 mph set speed, the proposed rule would save between 63 and 214 lives annually, monetized at between $716 million and $2.4 billion using both the value of statistical life in 2013 as well as economic costs and would also result in $848 million in fuel and emissions savings based on then-current price estimates.

The NPRM was based on a review of the available data, which suggested that limiting the speed of these heavy vehicles would reduce the severity of crashes involving these vehicles. However, NHTSA and FMCSA were not able to estimate the effects of speed reduction on the number of crashes occurring ( i.e., collision avoidance), and the proposal did not include estimated costs or benefits related to crash reductions or increases. The NPRM sought comment on the analysis of the costs and benefits of amending the Federal Motor Vehicle Safety Standards (FMVSS) and Federal Motor Carrier Safety Regulations (FMCSRs) to require speed limiting devices and their usage.

Comments were solicited on the NPRM for a total of 90 days, ending December 7, 2016. A total of 7,225 comments were received by that date  2 from individuals, motor carriers, industry organizations, and advocacy groups.

Individual drivers supporting the NPRM discussed a variety of topics. Many drivers of light vehicles ( i.e., vehicles with a GVWR of less than 3,856 kilograms (8,500 pounds)) supported the NPRM, stating that it would contribute to overall driving safety. They gave numerous examples of perceived dangerous driving by heavy vehicles based upon personal experiences and asserted that slowing down heavy vehicles would improve safety. Many individuals who responded in favor of the NPRM indicated that the rule should be expanded to apply to all heavy vehicles that already have speed governing equipment installed by the manufacturer.

Individual drivers opposed to the NPRM raised concerns about a host of potential impacts. The most common concern was about the potential speed differential between speed-limited heavy vehicles and light vehicles. Commenters indicated the relative differences in vehicle speeds could lead to more interactions between heavy vehicles heavy and light vehicles and could lead to increased or risky driving behavior by light vehicles trying to pass the slower heavy vehicles. Many commenters stated that the proposed requirements would slow traffic in general, particularly if two speed-limited heavy vehicles tried to pass one another. Some commenters stated that speed limiters would lead to increased speeding by heavy vehicles on surface streets with lower speed limits due to drivers trying to make up time. Others stated that the proposed rule would amount to government over-regulation, and result in increased costs for the trucking industry and slower overall delivery times. Commenters suggested increasing training for both heavy truck and light vehicle drivers as well as the alternative of increasing enforcement of existing speed limit laws.

The comments received from industry and advocacy groups were also mixed. Those in favor of the proposed rule, like Coach USA, supported a 68 mph speed limit, indicating that, as of December 2016, they have been using speed limiters in their fleet of buses for about 10 years, and that their speed limiters are set to 68 mph. The Insurance Institute for Highway Safety (IIHS) supported the NPRM, stating that lowering speeds would also lower the kinetic energy of crashes (thus reducing injuries), and that speed differentials already exist between trucks and cars on the highway. IIHS stated that the rule should require speed limiters to be added to existing heavy vehicles. Some opposing the rule, like the Michigan Department of Transportation (MDOT), stated that it would set a national speed limit for trucks, preempting State laws. MDOT also stated that the increased speed differential between heavy vehicles and light vehicles would possibly lead to more crashes. The Owner-Operator Independent Drivers Association (OOIDA) stated that speed limiters would increase driver fatigue and “[t]he agencies have made no attempt to examine the externalities of a speed limiter mandate other than to evaluate the societal costs incurred at the event of a heavy vehicle crash, whereas congestion costs are largely omitted.”

In the NPRM, three different speed limits were analyzed for heavy vehicles: 60, 65, and 68 mph. Analysis was conducted on each speed limit with the predicted improvement to safety given for each speed. The NPRM requested that commenters indicate which speed would be most appropriate. Relatively few of the commenters responded to this request. Among those that did, the preferred speed was nearly evenly split among the three proposed speeds.

On May 4, 2022, FMCSA published in the Federal Register (87 FR 26317) an ANSPRM announcing the Agency's intent to proceed with a speed limiter rulemaking to follow up on the joint 2016 NPRM. The ANSPRM explained that FMCSA intended to issue an SNPRM that, if adopted, would impose speed limitations on certain CMVs subject to the FMCSRs. Specifically, the Agency indicated that it would propose to require motor carriers to limit speeds for certain CMVs operated in interstate commerce that were already equipped with an electronic engine control unit (ECU) capable of setting speed limits. The maximum speed of affected CMVs was to be determined by the rulemaking, and motor carriers would have been required to maintain that maximum limit in the ECU for the service life of the vehicle.

FMCSA solicited comments concerning the ANSPRM for a total of 75 days, ending July 18, 2022. A total of 15,638 comments were received by that date. The comments were from individuals, motor carriers, industry associations, safety advocacy groups, technology developers, governmental entities, and research organizations. The issues raised by commenters to the ANSPRM, both supporting and opposing, were largely identical to those raised by commenters to the 2016 NPRM. Public comments were varied in both support and opposition to the proposals discussed in the ANSPRM. In many cases, a given commenter argued both in support of certain provisions of a proposed rule and in opposition to other provisions. Commenters included CMV drivers, trucking and bus companies, industry associations, safety organizations, technology developers, a research institute, and a non-law enforcement governmental entity. The comments and FMCSA responses are organized topically and summarized below.

Overall, approximately 300 comments provided some type of support for continued development of the proposals described in the ANSPRM. Commenters supporting the notice generally identified increased highway safety and positive impacts on truck drivers, the trucking industry, the economy, and the environment as reasons to support the ECU carrier-based approach. Commenters that included a government entity, safety organizations, and industry organizations, such as The Trucking Alliance, National Safety Council, Safe Operating Speed Alliance, C.R. England, Inc, National Transportation Safety Board, Truckload Carriers Association (TCA), The Law Firm for Truck Safety LLP, Institute for Safer Trucking, and Road Safe America supported the implementation of required speed limiter technology throughout the trucking industry in order to increase highway safety overall for all drivers and vehicles. Certain commenters, including Road Safe America, TCA, The Law Firm for Truck Safety LLP, and Advocates, supported using speed limiting devices and stated that the technology has been around for some time. A few even suggested maximum speeds to be considered in a proposed rulemaking. The Law Firm for Truck Safety LLP supported the ANSPRM and cited the positive impacts the proposal would have on truck drivers based on interviews of truck drivers conducted in the summer of 2022.

Certain individuals and safety organizations believed that the proposals would improve fuel efficiency and provide positive impacts on the environment. These commenters included The Law Firm for Truck Safety, LLP, and IIHS, which also supported the ANSPRM from a carrier-based approach.

More than 15,000 comments included statements opposing the rulemaking. Some questioned FMCSA's authority and whether the proposal would reduce highway safety by creating speed differentials and increasing traffic congestion. The opponents also cited potential impacts on the industry, driver pay, the economy, and the environment.

Commenters questioning FMCSA's statutory authority included the Texas Public Policy Foundation and several industry organizations, including OOIDA; AWM Associates, LLC; and SSTL Inc. Numerous individuals, companies and industry organizations such as OOIDA, United Parcel Service, and Real Women in Trucking, cited concerns that there would be a reduction in highway safety due to speed differentials and traffic congestion that would potentially reduce drivers' ability to merge or pass and would thereby increase traffic, which could lead to fatigue, aggressive driving, and other less safe driving situations.

Several commenters, including OOIDA, indicated that limiting a truck's speed would have adverse impacts on driver's' incomes, because reducing travel speeds would reduce the number of miles traveled as well as the number of pick-ups and deliveries. Other commenter issues included higher fuel costs, impacts to driver well-being and ease of parking due to additional hours a driver might have to spend driving to complete a job. Those commenters included OOIDA, the American Bus Association, and the Kansas Livestock Association. There were similar concerns regarding impacts to the trucking industry, economy, and environment. Numerous agricultural organizations and many individuals expressed concerns related to supply chain issues that they stated would place small business owners at a disadvantage in meeting deadlines. Many individual commenters also expressed concern that the proposal would cause drivers to leave the industry, which many noted is already experiencing a driver shortage.

A few commenters also expressed opposition to a carrier-based approach, stating that most vehicle crashes are caused by passenger cars, and some even suggested training drivers in all license classes to be aware of CMVs.

NHTSA and FMCSA have determined that the 2016 NPRM lacks a sufficiently clear and compelling safety justification for its implementation and raises significant concerns regarding federalism. NHTSA and FMCSA's research and analyses contained significant data gaps regarding potential safety benefits and economic impacts, and information obtained through the public comment process did not provide the information necessary to proceed to a final rule. NHTSA and FMCSA therefore withdraw the September 7, 2016 NPRM. For the same reasons, FMCSA also withdraws the May 4, 2022 ANSPRM.

The benefits estimation in the NPRM was based on the value of equivalent lives saved, plus property damage reduction, plus fuel savings. This analysis had limitations, which together create significant uncertainty regarding its conclusions.

First, considering advancements made in crash avoidance technologies in recent years, NHTSA and FMCSA believe there is a large degree of uncertainty about the baseline number of crashes ( i.e., the crashes projected to occur without the rulemaking in the future), which calls into question the magnitude of the estimated safety benefits of the rulemaking. In particular, rear-end crashes involving heavy vehicles (where the truck is the striking vehicle) could be reduced by crash avoidance technologies designed to mitigate or prevent such crashes, such as automatic emergency braking (AEB) and forward collision warning (FCW). 3 An increasing percentage of vehicles, including heavy vehicles, will be equipped with crash avoidance technologies in the future as more fleet owners purchase trucks with those technologies. 4

On October 16, 2015, NHTSA granted a petition for rulemaking to establish a safety standard to require automatic forward collision avoidance and mitigation systems on certain heavy vehicles (80 FR 62487). On July 6, 2023, NHTSA and FMCSA published a joint NPRM proposing to adopt a new FMVSS to require AEB systems on heavy vehicles, i.e., vehicles with a GWVR greater than 4,536 kilograms (10,000 pounds), and new FMCSRs to require mandated AEB and electronic stability control (ESC) systems to be active during vehicle operation (88 FR 43174). An AEB system uses multiple sensor technologies and sub-systems that work together to sense when the vehicle is in a crash imminent situation and applies the vehicle brakes automatically if the driver has not done so or applies more braking force automatically to supplement the driver's applied braking. The NPRM followed NHTSA's 2015 grant of the petition mentioned above. The NPRM also responded to a mandate under section 23010 of the Infrastructure Investment and Jobs Act (IIJA) (Pub. L. 117-58, 135 Stat. 429, 766, Nov. 15, 2021). IIJA section 23010 directs the Department to prescribe an FMVSS that requires heavy CMVs with an FMVSS-required electronic stability control (ESC) system to be equipped with an AEB system. IIJA section 23010 further directs the Department to prescribe an FMCSR that requires such heavy CMVs to use their FMVSS-mandated AEB systems at any time the CMV is operating. The NPRM proposed FMCSRs requiring the ESC and AEB systems to be active during vehicle operation.

NHTSA and FMCSA believe a portion of the crashes that they assumed would be mitigated by speed limiters may also be mitigated by AEB and FCW systems. ATA commented that safety technologies such as AEB and adaptive cruise control have evolved since the publication of the 2016 NPRM and may mitigate some of the concerns about speed differentials, productivity, and safety. Both ATA and Road Safe America advocated for establishing a higher speed limiter setting of 70 mph for vehicles equipped with and using AEB and AEC. However, OOIDA  5 and an anonymous commenter expressed concern that AEB triggers false or unexpected activation of the brake system and causes dangerous driving situations. Because advanced crash avoidance technologies that could prevent or mitigate crashes affected by the 2016 NPRM were not considered, the baseline in the analysis may not accurately project potential safety benefits and costs of speed limiting devices. Regulation in this area should not proceed until a more certain assessment of the effect of advanced crash avoidance technologies can be made, which would inform the analysis of the potential impacts of speed limiter technologies. The voluntary development and adoption of new crash-avoidance technologies, such as AEB, demonstrates that markets are progressing toward goals similar to those a speed limiter regulation would be expected to achieve. All recently manufactured heavy vehicles come equipped with the speed limiting devices (in the form of ECUs); the withdrawal of the NPRM and ANSPRM has no impact on the ability of operators to use those devices to manage speeds. Various operators have set maximum speeds voluntarily, in part to realize many of the fuel-saving and assumed safety benefits that users attribute to the devices. The withdrawal of the proposal will have no effect on the availability of speed limiting devices and the ability of operators to limit the speed of their own vehicles if they so choose.

Second, the NPRM did not include an estimate of crashes avoided or caused. It remains unclear whether implementing the NPRM would lead to a net increase in crashes, including those involving motorists striking the rear of CMVs at a device-limited speed, which NHTSA and FMCSA have been unable to quantify. Research varies on the topic of speed differentials and their impact on crash rates. 6

The comments did not include any clear research not already cited in the 2016 NPRM that could be used to establish the safety impacts associated with crash avoidance characteristics of the proposed rule. NHTSA and FMCSA received some comments that referenced international studies that reported specific changes in crash rates during the time period for which speed limiting devices were implemented internationally; however, it is not clear that these rate changes can be attributed to speed limiting devices, or that the same crash rate changes could be anticipated for traffic conditions in the United States. 7 One concern about international studies is that drivers behave differently in different countries and have different risk-tolerances. In addition, trucks in other countries may differ from those in the U.S. in terms of size and shape. Other comments referenced another study that was unable to provide specific quantitative risks associated with the installation of speed limiting devices and the risks associated with different car and truck travel speeds. 8 NHTSA and FMCSA do not have reliable estimates of crash avoidance benefits based on trucks driving at lower speeds or of a possible reduction in safety resulting from the risks associated with speed differentials.

Third, Executive Order (E.O.) 12866, Regulatory Planning and Review (58 FR 51735 (Oct. 4, 1993)), directs agencies to tailor their regulations to impose the least burden on society, including individuals and businesses of differing sizes, consistent with obtaining the regulatory objectives, considering, among other things, and to the extent practicable, the costs of cumulative regulations. The crash avoidance technologies under development may achieve the safety goals of this rulemaking better than a speed limiter requirement. The potential effects of the rulemaking on trucking commerce are difficult to predict because they would affect a wide range of economic activities, a limited subset of which were explored in the Preliminary Regulatory Impact Analysis (PRIA) and NPRM. As discussed in the PRIA and NPRM, NHTSA and FMCSA are unable to predict the secondary impacts of a speed limiter requirement, such as the rebound effect (as the fuel used per mile would likely decline) and driver wage rates (which have historically been based on miles, rather than hours, driven), which could have significant impacts on the trucking industry. 9 Moreover, NHTSA and FMCSA estimated that the rulemaking could put small owner-operators at a disadvantage in some circumstances, resulting in a reduction in profits (81 FR 61942, 61694).

Fourth, E.O. 14219, Ensuring Lawful Governance and Implementing the President's “Department of Government Efficiency” Deregulatory Initiative (90 FR 10583 (Feb. 25, 2025)), directs agencies to rescind regulations that are unlawful or undermine the National interest. It establishes classes of regulations that should be reviewed for rescission or modification, including “(iii) regulations that are based on anything other than the best reading of the underlying statutory authority or prohibition.” In light of comments from the Texas Public Policy Foundation and OOIDA stating that the 2016 NPRM would violate section 205(d) of the National Highway System Designation Act of 1995 (Pub. L. 104-59, 109 Stat. 568, 577, Nov. 28, 1995, which repealed the national maximum speed limit enacted in 1975 that was formerly codified at 23 U.S.C. 154), the proposed rule could be viewed as inconsistent with the prohibition on the adoption of traffic safety regulations in 49 U.S.C. 31147(a). Therefore, NHTSA and FMCSA believe it is appropriate to withdraw this rulemaking, consistent with the intent of E.O. 14219.

Fifth, NHTSA and FMCSA are concerned about the uncertainty regarding industry response to daily driving distance limitations that could result from the rulemaking. Because the speeds under consideration were all below the legal speed limit applicable to these vehicles on many of the Nation's highways, the rulemaking would reduce the maximum potential distance a driver could theoretically travel in a single day within the maximum allowed hours of service if the driver is currently driving the maximum number of hours allowed by law. NHTSA and FMCSA assumed that industry would respond through a combination of increased driver efficiency and team driving when such response is feasible and practicable, but other responses, such as adding additional trucks to move the same amount of goods, might also occur. NHTSA and FMCSA did not consider the possibility that the rulemaking could result in an increase in the overall number of trucks required to be on the roads, which would lead to increased costs for those trucks, reduced overall fuel savings and environmental benefits, and possible safety disbenefits from greater exposure of drivers of light vehicles to vehicles with substantial speed differentials.

Sixth, NHTSA and FMCSA attempted to estimate the aggregate economic value lost due to the depreciation of goods as a result of slower travel speeds but have been unable to consider how the cost would be distributed across industry sectors, particularly to deliveries that are time-sensitive, such as those in the agricultural industry. While commenters suggested that the rule would affect certain industry sectors disproportionately, they did not provide data to enable NHTSA and FMCSA to quantify this effect.

Seventh, while NHTSA and FMCSA considered the costs to truck operators resulting from longer travel times, they have been unable to account for the potential delays and other costs to other road users, caused by factors such as decreased speed of other vehicles traveling resulting from an inability to pass slower moving heavy vehicles. Although the potential for delays to other road uses was an issue raised by many commenters, they did not provide data enabling NHTSA and FMCSA to quantify the magnitude of this effect.

Finally, if implemented, the proposal could have, over time, displaced State authority to set speed limits for heavy vehicles, given that the speeds under consideration in the 2016 NPRM (60 mph, 65 mph, and 68 mph) are below the maximum posted daytime speed limits on many roads, including rural Interstates in over half of the States. Because many States have determined that it is safe for heavy vehicles to operate above 68 mph on certain roads, the rulemaking would, in effect, undercut the ability of those States to set the speed limits they have deemed appropriate on their roadways.

Accordingly, for the reasons discussed above, the NPRM published in the Federal Register on September 7, 2016 at 81 FR 61942, is hereby withdrawn. FMCSA also withdraws the May 4, 2022 ANSPRM. This action is considered a deregulatory action under E.O. 14192, Unleashing Prosperity Through Deregulation (90 FR 9065, Jan. 31, 2025), as it withdraws an NPRM that was issued before January 20, 2025 that was determined to be “significant” under E.O. 12866.

Issued under authority delegated in 49 CFR 1.87 concerning FMCSA, and 49 CFR 1.95, 501.4, and 501.5 concerning NHTSA.