The Secretary of Agriculture is authorized by section 10314 of the OBBBA (Pub. L. 119-21) to conduct mandatory surveys of dairy product manufacturing cost data and related dairy product yield information for all products produced at a plant or plants required to report price information under the Dairy Products Mandatory Reporting Program (defined in section 273 of the Agricultural Marketing Act of 1946 (7 U.S.C. 1637b)). The AMS Dairy Program will collect, verify, analyze, and aggregate survey results and publish a biennial Manufacturing Cost and Product Yield Report (Biennial Report). In an effort to conduct mandatory manufacturing cost and product yield surveys and issue Biennial Reports that successfully meet the statutory requirement, this ANPR seeks input from impacted dairy stakeholders on data collection information and processes, cost calculation methodologies, verification procedures, and reporting needs.

USDA anticipates establishing a cost reporting program similar to previous voluntary industry manufacturing cost surveys. As such, USDA is planning to collect data on input expenses and utilize defined methodologies to calculate survey results. USDA also will establish a process for collecting and calculating product yield information. USDA will define a verification process for ensuring accuracy and consistency of input expenses and yield information collected from required reporters. After verifying and analyzing the collected data, USDA will issue a Biennial Report every 2 years providing cost and yield statistics for the commodities subject to price information reporting required by the Dairy Products Mandatory Reporting Program (DPMRP). Currently, those products include butter, cheddar cheese (40-pound blocks), dry whey, and nonfat dry milk. All data published will be subject to DPMRP confidentiality metrics. Specifically, only the aggregated data of no fewer than three plants—with no one entity representing more than 60 percent of the volume of commodity surveyed—will be published. This would ensure the data of any one plant or entity cannot be identified.

To establish the manufacturing cost and product yield surveys, USDA must determine: what data to collect; the methodologies for collecting, analyzing, and verifying the data; and the information to be included in the legislatively required Biennial Report. As part of the development process, AMS seeks comments on the manufacturing cost and product yield surveys. All interested parties are encouraged to provide input during the comment period. Following this ANPR, AMS will publish a proposed rule for public comment. AMS also seeks comments from the public on the following:

1. Past voluntary industry manufacturing cost surveys collected various cost data after the plant acquired milk and dairy ingredients, but before the finished product left the manufacturer. Examples of some categories include labor (processing), non-labor (processing), utilities, product volume, dairy ingredient inputs, other ingredients, general and administrative, packaging, and return on investment. Are these appropriate categories or should these categories be adjusted? What specific data points should be included in each category?

2. Not all plants maintain detailed data that allows for the easy allocation of input expenses to various product lines and, therefore, must employ allocation rules to calculate costs. For unallocated input expenses, what methodology should be used for allocating such expenses to individual product categories?

3. What timeframe should USDA use to survey cost data ( e.g., the January—December calendar year, the most recent 12-month period, the individual plant specific fiscal year)? If the survey requests the submission of 12 months of data, how soon will plants be able to submit data? Do plants have the capability to submit the data on a monthly and annual basis, if requested?

4. OBBBA specifies that USDA should publish a Biennial Report but does not provide specifics on the data collection schedule. What factors should USDA consider when setting its data collection schedule? Comments are requested on the following data collection schedules: (1) collect two years of data every two years ( i.e., collect 2025 and 2026 data in the 2027 survey (results would be published in the 2028 Biennial Report); (2) collect data every year, and publish two years' worth of data in the Biennial Report ( i.e., collect 2025 data in a 2026 survey, collect 2026 data in a 2027 survey, and publish both the 2025 and 2026 data in the 2028 Biennial Report); or (3) only collect one year of data every other year ( i.e., collect 2026 data in a 2027 survey and publish it in a 2028 Biennial Report).

5. What data should USDA consider when determining product yields?

6. To ensure survey data are accurate and consistent, USDA will define a verification process in the proposed rule. As part of the review process, reporting entities will need to make records available upon request. How long are cost accounting records typically kept and what types of records could be used to provide cost and yield data?

Under Executive Order 12866, “Regulatory Planning and Review,” this action is not a “significant regulatory action.” Accordingly, AMS did not submit this ANPR to the Office of Management and Budget (OMB) for review under Executive Order 12866. Additionally, because this ANPR does not propose or impose any requirements—and instead seeks comments and suggestions for AMS to consider in a subsequent proposed rule—the various statutes and Executive Orders that normally apply to rulemaking do not apply to this ANPR. Should AMS subsequently publish a proposed rule, AMS will address the statutes and Executive Orders applicable to that proposed rule. AMS welcomes comments and/or information that would help assess any of the following:

1. The potential impact of a rule on small entities pursuant to the Regulatory Flexibility Act (RFA) (5 U.S.C. 601 et seq. );

2. Potential impacts on Federal, State, or local Governments pursuant to the Unfunded Mandates Reform Act (UMRA) (2 U.S.C. 1531-1538);

3. Federalism implications pursuant to Executive Order 13132, “Federalism”;

4. Tribal implications pursuant to Executive Order 13175, “Consultation and Coordination with Indian Tribal Governments”; or

5. Paperwork burdens pursuant to the Paperwork Reduction Act (44 U.S.C. 3501).

AMS will consider any comments received in response to this ANPR during the development of any subsequent proposed rulemaking.

This rulemaking is separate from NRC's comprehensive review and reform of its regulations in accordance with Executive Order (E.O.) 14300, “Ordering the Reform of the Nuclear Regulatory Commission” (90 FR 22587; May 29, 2025). The rulemakings associated with that effort will comprehensively reexamine NRC requirements, including those in 10 CFR part 50. While there could be additional revisions to 10 CFR part 50 as a result of these future rulemakings, the NRC is moving forward with publication of this proposed rule at this time because it is a deregulatory action of high interest for stakeholders that was in progress before the issuance of E.O. 14300.

The NRC is proposing to amend its regulations to incorporate by reference the 2023 Edition of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPV Code). The ASME periodically revises and updates its Codes for nuclear power plants by issuing new editions; this proposed rule is in accordance with the NRC's practice to incorporate those new editions into the NRC's regulations. This proposed rule maintains the safety of nuclear power plants, makes NRC activities more effective and efficient, and allows nuclear power plant licensees and applicants to take advantage of the latest ASME BPV Code. The ASME is a voluntary consensus standards organization, and the ASME BPV Code is a voluntary consensus standard. The NRC's use of the ASME BPV Code is consistent with applicable requirements of the National Technology Transfer and Advancement Act (NTTAA). See Section XIV, “Voluntary Consensus Standards,” of this document for more information.

In addition, the NRC is proposing to incorporate by reference into its regulations the latest revisions of three regulatory guides (RGs) (currently in draft form for comment). The three draft RGs identify new, revised, and reaffirmed code cases published by the ASME that the NRC has determined are acceptable for use as voluntary alternatives to compliance with certain provisions of the ASME BPV Code and the ASME Operation and Maintenance (OM) of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code) currently incorporated by reference into the NRC's regulations. The NRC is also proposing to revise an additional RG listing code cases that the NRC has not approved for use.

Major provisions of this proposed rule include the incorporation by reference with conditions of the 2023 Edition of the ASME BPV Code into NRC regulations and delineation of NRC requirements for the use of this code. In addition, the NRC proposes to incorporate by reference into the NRC's regulations the following regulatory guides: RG 1.84, “Design, Fabrication, and Materials Code Case Acceptability, ASME Section III,” Revision 41 (Draft Regulatory Guide (DG)-1446); RG 1.147, “Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1,” Revision 22 (DG-1447); and RG 1.192, “Operation and Maintenance [OM] Code Case Acceptability, ASME OM Code,” Revision 6 (DG-1448). This proposed action would allow nuclear power plant licensees and applicants for construction permits, operating licenses, combined licenses, standard design certifications, standard design approvals, and manufacturing licenses to use the code cases newly listed in these revised RGs as voluntary alternatives to ASME engineering standards for the construction, inservice inspections, and inservice testing of nuclear power plant components. The NRC also notes the availability of a proposed version of RG 1.193, “ASME Code Cases Not Approved for Use,” Revision 9 (DG-1449). This document lists code cases that the NRC has not approved for generic use and would not be incorporated by reference into the NRC's regulations.

The NRC prepared a draft regulatory analysis to determine the expected quantitative costs and benefits of this proposed rule, as well as qualitative factors to be considered in the NRC's rulemaking decision. The analysis concluded that this proposed rule would result in net savings to the industry and the NRC. As shown in Table I, the estimated total net benefit relative to the regulatory baseline and the quantitative benefits would outweigh the costs by a range from approximately $9.52 million (7-percent net present value) to $11.7 million (3-percent net present value).

The draft regulatory analysis also considered the following qualitative considerations: (1) protection of public health and safety and the environment; (2) consistency with the provisions of the National Technology Transfer and Advancement Act of 1995, which encourages Federal regulatory agencies to consider adopting voluntary consensus standards as an alternative to de novo agency development of standards affecting an industry; (3) consistency with the NRC's policy of evaluating the latest versions of consensus standards in terms of their suitability for endorsement by regulations and regulatory guides; and (4) consistency with the NRC's goal to harmonize with international standards to improve regulatory efficiency for both the NRC and international standards groups.

The NRC has had a decades-long practice of approving and/or mandating the use of certain parts of editions and addenda of ASME Codes and certain ASME Code Cases in § 50.55a through the rulemaking process of “incorporation by reference.” Continuing this practice in this proposed rule ensures regulatory stability and predictability. This practice also provides consistency across the industry and provides assurance to the industry and the public that the NRC will continue to support the use of the most updated and technically sound techniques developed by the ASME to provide adequate protection to the public. The ASME Codes are voluntary consensus standards developed by technical committees composed of mechanical engineers and others who represent the broad and varied interests of their industries, from manufacturers and installers to insurers, inspectors, distributors, regulatory agencies, and end users. The standards undergo extensive external review before the NRC considers whether to incorporate them by reference. Finally, the NRC's use of the ASME Codes is consistent with the NTTAA, which directs Federal agencies to adopt voluntary consensus standards instead of developing “government-unique” ( i.e., Federal agency-developed) standards, unless inconsistent with applicable law or otherwise impractical.

The draft regulatory analysis concludes that this proposed rule should be adopted because it is justified when integrating the cost-beneficial quantitative results and the positive and supporting nonquantitative considerations in the decision. For more information, please see the draft regulatory analysis as indicated in Section XVII, “Availability of Documents,” of this document.

Please refer to Docket ID NRC-2020-0029 when contacting the NRC about the availability of information for this action. You may obtain publicly available information related to this action by any of the following methods:

• Federal Rulemaking Website: Go to https://www.regulations.gov and search for Docket ID NRC-2020-0029.

• NRC's Agencywide Documents Access and Management System (ADAMS): You may obtain publicly available documents online in the ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html. To begin the search, select “Begin ADAMS Public Search.” For problems with ADAMS, please contact the NRC's Public Document Room (PDR) reference staff at 1-800-397-4209, at 301-415-4737, or by email to PDR.Resource@nrc.gov. For the convenience of the reader, instructions about obtaining materials referenced in this document are provided in the “Availability of Documents” section.

• NRC's PDR: The PDR, where you may examine and order copies of publicly available documents, is open by appointment. To make an appointment to visit the PDR, please send an email to PDR.Resource@nrc.gov or call 1-800-397-4209 or 301-415-4737, between 8 a.m. and 4 p.m. eastern time, Monday through Friday, except Federal holidays.

• Technical Library: The Technical Library, which is located at Two White Flint North, 11545 Rockville Pike, Rockville, Maryland 20852, is open by appointment only. Interested parties may make appointments to examine documents by contacting the NRC Technical Library by email at Library.Resource@nrc.gov between 8 a.m. and 4 p.m. eastern time, Monday through Friday, except Federal holidays.

The NRC encourages electronic comment submission through the Federal rulemaking website ( https://www.regulations.gov ). Please include Docket ID NRC-2020-0029 in your comment submission.

The NRC cautions you not to include identifying or contact information that you do not want to be publicly disclosed in your comment submission. The NRC will post all comment submissions at https://www.regulations.gov as well as enter the comment submissions into ADAMS. The NRC does not routinely edit comment submissions to remove identifying or contact information.

If you are requesting or aggregating comments from other persons for submission to the NRC, then you should inform those persons not to include identifying or contact information that they do not want to be publicly disclosed in their comment submission. Your request should state that the NRC does not routinely edit comment submissions to remove such information before making the comment submissions available to the public or entering the comment into ADAMS.

The American Society of Mechanical Engineers (ASME) develops and publishes the ASME Boiler and Pressure Vessel (BPV) Code, which contains requirements for the design, construction, and inservice inspection (ISI) of nuclear power plant components. Until 2012, the ASME issued new editions of the ASME BPV Code every 3 years and addenda to the editions annually, except in years when a new edition was issued. Starting in 2012, the ASME decided to issue editions of its BPV Code (no addenda) every 2 years on the odd years ( e.g., 2013, 2015, etc.). The new editions typically revise provisions of the ASME BPV Code to broaden their applicability, add specific elements to current provisions, delete specific provisions, and/or clarify them to narrow the applicability of the provision. The revisions to the editions of the ASME BPV Code do not significantly change code philosophy or approach.

The ASME also develops and publishes the ASME Operation and Maintenance (OM) Code, which contains requirements for inservice testing (IST) of nuclear power plant components. The ASME periodically publishes new editions and addenda of the ASME OM Code. Starting in 2012, the ASME decided to issue editions of its OM Code (no addenda) every 2 years on the even years ( e.g., 2012, 2014, etc.). However, the ASME did not publish a 2024 edition of the OM Code.

The NRC's practice is to establish requirements for the design, construction, operation, ISI (examination), and IST of nuclear power plants by approving the use of editions of the ASME BPV and OM Codes (ASME Codes) in § 50.55a of title 10 of the Code of Federal Regulations (10 CFR). The NRC approves or mandates the use of certain parts of editions of these ASME Codes in § 50.55a through the rulemaking process of incorporation by reference. Upon incorporation by reference of the ASME Codes into § 50.55a, the provisions of the ASME Codes are legally-binding NRC requirements as delineated in § 50.55a, and subject to the conditions on certain specific ASME Codes' provisions that are set forth in § 50.55a. The most recent editions of the ASME Codes were last incorporated by reference into the NRC's regulations in a final rule dated August 30, 2024 (89 FR 70449).

The ASME Codes are voluntary consensus standards developed by participants, including the NRC and licensees of nuclear power plants, who have broad and varied interests. The ASME's adoption of new editions of the ASME Codes does not mean that there is unanimity on every provision in the ASME Codes. There may be disagreement among the technical experts, including the NRC's representatives on the ASME Code committees and subcommittees, regarding the acceptability or desirability of a particular code provision included in an ASME-approved Code edition. If the NRC believes that there is a significant technical or regulatory concern with a provision in an ASME-approved Code edition being considered for incorporation by reference, then the NRC conditions the use of that provision when it incorporates by reference that ASME Code edition into its regulations. In some instances, the condition increases the level of safety afforded by the ASME Code provision, or addresses a regulatory issue not considered by the ASME. In other instances, where research data or experience has shown that certain code provisions are unnecessarily conservative, the condition may provide that the code provision need not be complied with in some or all respects. The NRC's conditions are included in § 50.55a, typically in paragraph (b) of that section. In a Staff Requirements Memorandum (SRM) dated September 10, 1999, the Commission indicated that NRC rulemakings adopting (incorporating by reference) a voluntary consensus standard must identify and justify each part of the standard that is not adopted. For this proposed rule, the provisions of the 2023 Edition of Section III, Division 1, and the 2023 Edition of Section XI, Division 1, of the ASME BPV Code that the NRC is not adopting, or is only partially adopting, are identified in the “Discussion,” “Regulatory Analysis,” and “Backfitting and Issue Finality” sections of this document. The provisions of those specific editions and code cases that are the subject of this proposed rule that the NRC finds to be conditionally acceptable, together with the applicable conditions, are also identified in the “Discussion,” “Regulatory Analysis,” and “Backfitting and Issue Finality” sections of this document.

The ASME Codes are voluntary consensus standards, and the NRC's incorporation by reference of these Codes is consistent with applicable requirements of the National Technology Transfer and Advancement Act (NTTAA). Additional discussion on the NRC's compliance with the NTTAA is set forth in Section XIV of this document, “Voluntary Consensus Standards.”

The ASME develops and publishes the ASME BPV Code, which contains requirements for the design, construction, and inservice inspection of nuclear power plant components, and the ASME OM Code, which contains requirements for preservice and inservice testing of nuclear power plant components. In response to BPV and OM Code user requests, the ASME develops code cases that provide voluntary alternatives to BPV and OM Code requirements.

The NRC approves the ASME Codes in § 50.55a, “Codes and standards,” through the process of incorporation by reference. As such, each provision of the ASME Codes incorporated by reference into and mandated by § 50.55a constitutes a legally-binding NRC requirement imposed by rule. As noted previously, the ASME Code cases, for the most part, represent alternative approaches for complying with provisions of the ASME BPV and OM Codes. Accordingly, the NRC periodically amends § 50.55a to incorporate by reference the NRC's regulatory guides (RGs) listing approved ASME Code cases that may be used as voluntary alternatives to the BPV and OM Codes.

This proposed rule is the latest in a series of rules that incorporate by reference new versions of several RGs that identify new, revised, and reaffirmed ASME Code cases that the NRC unconditionally or conditionally approves for use. In developing these RGs, the NRC reviews the ASME BPV and OM Code Cases, determines the acceptability of each code case, and publishes its findings in the RGs. The RGs are revised periodically as new code cases are published by the ASME. The NRC incorporates by reference the RGs listing acceptable and conditionally acceptable ASME Code Cases into § 50.55a. The NRC published a final rule dated July 17, 2024 (89 FR 58039), that incorporated by reference into § 50.55a the most recent versions of the RGs, which are RG 1.84, “Design, Fabrication, and Materials Code Case Acceptability, ASME Section III,” Revision 40; RG 1.147, “Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1,” Revision 21; and RG 1.192, “Operation and Maintenance Code Case Acceptability, ASME OM Code,” Revision 5.

In a direct final rule (DFR) (90 FR 46319; [published September 26, 2025, effective January 26, 2026]), the NRC incorporated by reference RG1.262, “ASME Code Cases Approved for Use Without Conditions.” This new approach to ASME Code Case rulemaking implements Commission direction in SRM-SECY-21-0029 regarding streamlining § 50.55a rulemaking activities. The NRC considers the code cases approved in RG 1.262 to be noncontroversial in nature without the need for regulatory conditions, such that issuing a DFR is an appropriate rulemaking process. This approach allows the NRC to approve such code cases in a more efficient manner than was possible under the former process (see final rule, “American Society of Mechanical Engineers Code Cases and Update Frequency,” issued July17,2024 (89 FR 58039)). In developing RG1.262, the NRC reviewed the ASME BPV and OM Code Cases, determined the acceptability of each code case, and published its findings in the RG. This RG will be revised periodically as the NRC determines that new code cases published by the ASME are acceptable without NRC regulatory conditions and are noncontroversial. Using this new approach, the NRC approved these ASME Code Cases for use by incorporating RG 1.262 by reference into § 50.55a. This rule supplements that DFR by addressing code cases that need additional NRC regulatory conditions or are otherwise potentially controversial.

The NRC regulations incorporate by reference ASME Codes for nuclear power plants. This proposed rule is the latest in a series of rulemakings to amend the NRC's regulations to incorporate by reference revised and updated ASME Codes for nuclear power plants. This proposed rule is intended to maintain the safety of nuclear power plants and make NRC activities more effective and efficient.

The NRC follows a three-step process to determine acceptability of new provisions in new editions of the ASME Codes and the need for conditions on the uses of these ASME Codes. This process was employed in the review of the ASME BPV Code that is the subject of this proposed rule. First, the NRC actively participates with other ASME committee members with full involvement in discussions and technical debates in the development of new and revised Code provisions. This includes technical justification of each new or revised Code provision. Second, the NRC's committee representatives discuss the Code provisions and technical justifications with other cognizant staff to ensure an adequate technical review. Third, the NRC position on each Code provision is reviewed and approved by NRC management as part of this proposed rule amending § 50.55a to incorporate by reference new editions of the ASME Codes and conditions on their use. This regulatory process, when considered together with the ASME's own process for developing and approving the ASME Codes, assures that the NRC approves for use only those new and revised code editions, with conditions as necessary, that provide reasonable assurance of adequate protection to the public health and safety, and that do not have significant adverse impacts on the environment.

The NRC reviewed changes to the ASME BPV Code identified in this proposed rule. The NRC concluded, in accordance with the process for review of changes to the Codes, that this edition of the Code is technically adequate, consistent with current NRC regulations, and approved for use with the specified conditions upon the conclusion of the rulemaking process.

The NRC is proposing to amend its regulations to incorporate by reference the 2023 Editions of the ASME BPV Code, Section III, Division 1 and Section XI, Division 1, with conditions on their use.

The current regulations in § 50.55a(a)(1)(i) incorporate by reference ASME BPV Code, Section III, 1963 Edition through the 1970 Winter Addenda; and the 1971 Edition (Division 1) through the 2021 Edition (Division 1), subject to the conditions identified in current § 50.55a(b)(1)(i) through (xiv). This proposed rule would revise § 50.55a(a)(1)(i) to incorporate by reference the 2023 Edition (Division 1) of the ASME BPV Code, Section III with Errata 23-2471, “NB-5332(a)(2) (from R/N 22-1562),” dated April 4, 2024. It also would clarify the wording and add or revise some of the conditions as explained in this proposed rule.

The current regulations in § 50.55a(a)(1)(ii) incorporate by reference ASME BPV Code, Section XI, 1974 Edition through the 1975 Summer Addenda, the 1995 Edition (Division 1) through the 1997 Addenda (Division 1), and the 2001 Edition (Division 1) through the 2021 Edition (Division 1), subject to the conditions identified in current § 50.55a(b)(2)(i) through (l). This proposed rule would revise § 50.55a(a)(1)(ii) to incorporate by reference the 2023 Edition (Division 1) of the ASME BPV Code, Section XI. It also would clarify the wording and add, remove, or revise some of the conditions as explained in this proposed rule.

In the introductory discussion of its Codes, ASME specifies that errata to those Codes may be posted on the ASME website under the Committee Pages to provide corrections to incorrectly published items, or to correct typographical or grammatical errors in those Codes. Users of the ASME Codes should be aware of errata when implementing the specific provisions of those Codes. Applicants and licensees should monitor errata to determine when they might need to submit a request for an alternative under § 50.55a(z) to implement provisions specified in an errata to their ASME Code of Record. Each of the proposed NRC conditions and the reasons for each are discussed in the following sections of this document. The discussions are organized under the applicable ASME Code and Section.

The NRC prepared an unofficial redline strikeout version of the proposed changes to regulatory text that is intended to help the reader identify the proposed changes. The unofficial redline strikeout version of the proposed rule is publicly available and provided in the “Availability of Documents” section.

The NRC proposes to revise § 50.55a(a)(1)(i)(E) to incorporate by reference the 2023 Edition of the ASME BPV Code, Section III, including Subsection NCA and Division 1 Subsections NB through NG and Appendices, with Errata 23-2471, “NB-5332(a)(2) (from R/N 22-1562),” dated April 4, 2024. As stated in § 50.55a(a)(1)(i), the Nonmandatory Appendices are excluded and not incorporated by reference. The Mandatory Appendices are incorporated by reference because they include information necessary for Division 1. However, the Mandatory Appendices also include material that pertains to other Divisions that have not been reviewed and approved by the NRC. Although this information is included in the sections and appendices being incorporated by reference, the NRC notes that the use of Divisions other than Division 1 has not been approved, nor are they required by NRC regulations and, therefore, such information is not relevant to NRC applicants and licensees. The NRC is not taking a position on the non-Division 1 information in the appendices and is including it in the incorporation by reference only for convenience. Therefore, this proposed rule revises the introductory text to § 50.55a(a)(1)(i)(E) to reference the 2023 Edition of the ASME BPV Code, Section III, including Subsection NCA and Division 1 Subsections NB through NG and Appendices, with Errata 23-2471, “NB-5332(a)(2) (from R/N 22-1562),” dated April 4, 2024.

The NRC proposes to revise § 50.55a(a)(1)(v)(B) to include the 2017, 2019, and 2022 editions of NQA-1. The 2017, 2019, and 2022 editions of NQA-1 were endorsed, with conditions, by the NRC in Revision 6 of RG 1.28.

The NRC proposes to revise § 50.55a(b)(1)(xiv) to extend the applicability of the condition through the latest edition of the ASME BPV Code, Section III incorporated by reference in paragraph (a)(1)(i). The 2023 Edition of Section III was not updated to include the provisions of this condition. Therefore, the NRC is proposing to revise this condition to apply to the latest edition incorporated by reference.

The NRC proposes to add condition § 50.55a(b)(1)(xv) to require that reasonable protection from deterioration of radiographic film specified in Note (3) to Table NCA-4134.17-1 and Note (1) to Table NCA-4134.17-2 of the 2023 Edition of the ASME BPV Code, Section III, must include the provisions in NCA-4134.17(c), and the reproduction must be retained as a record in accordance with Table NCA-4134.17-1 or NCA-4134.17-2, as applicable, of the 2023 Edition of Section III. A similar condition, § 50.55a(b)(2)(liii), is proposed in this rule for IWA-6310(b) of the 2023 ASME BPV Code, Section XI. The condition is in two provisions as follows:

NCA-4134.17(d) requires records listed in Table NCA-4134.17-1 to be classified as lifetime records and shall be retained and maintained for the life of the plant. In the 2023 Edition of the ASME BPV Code, Section III, Note (3) to Table NCA-4134.17-1 specifies that deterioration of radiographic film is expected and radiographic film that has deteriorated to the point where it no longer has value does not need to be maintained as a record by the owner.

However, the NRC notes that there are existing provisions in NCA-4134.17(c) that allow reproduction of radiographic film, including by electronic processes ( e.g., digitize) before the original film's deterioration. Therefore, the NRC is proposing to add § 50.55a(b)(1)(xv)(A) to condition Note (3) of Table NCA-4134.17-1 of the 2023 Edition of Section III to require that the reasonable protection from deterioration of radiographic film shall include the provisions specified in NCA-4134.17(c) of the 2023 Edition of Section III, and the reproduction must be retained as a lifetime record in accordance with Table NCA-4134.17-1 of the ASME BPV Code, Section III. This would maintain the current requirements in the 2021 Edition of the ASME BPV Code, Section III.

NCA-4134.17(e) requires records listed in Table NCA-4134.17-2 to be classified as nonpermanent records and shall be retained for the period specified in Table NCA-4134.17-2 (10 years for radiographic film). In the 2023 Edition of the ASME BPV Code, Section III, Note (1) to Table NCA-4134.17-2 specifies that deterioration of radiographic film is expected and radiographic film that has deteriorated to the point where it no longer has value does not need to be maintained as a record by the owner.

However, the NRC notes that there are existing provisions in NCA-4134.17(c) that allow reproduction of radiographic film, including by electronic processes ( e.g., digitize) before the original film's deterioration. Therefore, the NRC is proposing to add § 50.55a(b)(1)(xv)(B) to condition Note (1) of Table NCA-4134.17-2 of the 2023 Edition of Section III to require that the reasonable protection from deterioration of radiographic film shall include the provisions specified in NCA-4134.17(c) of the 2023 Edition of Section III, and the reproduction must be retained as a nonpermanent record in accordance with NCA-4134.17-2 of the ASME BPV Code, Section III. This would maintain the current requirements in the 2021 Edition of the ASME BPV Code, Section III.

The NRC proposes to amend the regulations in § 50.55a(a)(1)(ii)(C) to incorporate by reference the 2023 Edition (Division 1) of the ASME BPV Code, Section XI. The current regulations in § 50.55a(a)(1)(ii)(C) incorporate by reference ASME BPV Code, Section XI, the 1974 Edition through the 1975 Summer Addenda, the 1995 Edition (Division 1) through the 1997 Edition (Division 1), and the 2001 Edition (Division 1) through the 2021 Edition (Division 1), subject to the conditions identified in current § 50.55a(b)(2)(i) through (l).

The NRC proposes to remove and reserve § 50.55a(a)(1)(iii)(A) to delete the incorporation by reference of ASME BPV Code Case N-513-3, Mandatory Appendix I. This mandatory appendix was previously incorporated by reference as a reference for § 50.55a(b)(2)(xxxiv), Section XI Condition: Nonmandatory Appendix U. The reference to Mandatory Appendix I was removed from this condition in a previous rulemaking, and Mandatory Appendix I is no longer referenced in this section. Therefore, this proposed rule would remove and reserve § 50.55a(a)(1)(iii)(A).

The NRC proposes to revise § 50.55a(b)(2)(xii) to limit the applicability of the condition to the 2001 Edition through the 2021 Edition of ASME BPV Code, Section XI. The current regulations in § 50.55a(b)(2)(xii) state that the condition applies to the latest edition and addenda incorporated by reference in § 50.55a(a)(1)(ii). In the 2023 Edition of ASME BPV Code, Section XI, ASME modified subparagraph IWA-4661(f) to add provisions that satisfy the conditions in § 50.55a(b)(2)(xii). Therefore, these conditions do not apply to the 2023 Edition.

The NRC proposes to remove and reserve the first provision of this condition in § 50.55a(b)(2)(xviii)(A). The current regulations in § 50.55a(b)(2)(xviii) provide four provisions related to qualification rules for nondestructive evaluation (NDE) personnel. The condition was added in 2002 (67 FR 60520) when the 1997 Addenda, and 1998 and later Editions of ASME Code, Section XI revised the requirement for recertification of Level I and Level II NDE personnel from 3 years to 5 years. This was before the widespread implementation of ASME BPV Code, Section XI, Appendix VIII rules for the performance demonstration requirements for personnel performing ultrasonic testing (UT). At that time the NRC had lower confidence in the quality of the qualifications for the NDE personnel, equipment, and procedures.

ASME provided the NRC a letter dated August 23, 2024, describing the basis for removing the provision. The basis can be summarized as saying that changes and improvements to the 8-hour, hands-on practice work done by NDE personnel mandated by § 50.55a(b)(2)(xiv) have been shown to maintain the proficiency of NDE personnel. Experience with 5-year recertifications in non-nuclear fields and internationally with ISO 9712, “Non-destructive testing—Qualification and certification of NDT personnel,” supports their contention that a 5-year recertification rate does not adversely impact the skill levels of the NDE personnel. The NRC agrees that the improvements in NDE rigor and experience with the 8-hour, hands-on training have shown that a 5-year recertification rate is acceptable and will provide adequate proficiency for NDE personnel.

Additionally, the NRC proposes to revise § 50.55a(b)(2)(xviii)(D) to clarify that the alternatives listed in paragraphs (b)(2)(xviii)(D)(1) and (2) are applicable to ASME BPV Code, Section XI, editions and addenda later than the 2010 Edition. When using these editions and addenda, the current provision to this condition requires licensees and applicants to use the prerequisites for ultrasonic examination personnel certifications in Appendix VII, Table VII-4110-1 and Appendix VIII, Subarticle VIII-2200 in the 2010 Edition. Although alternatives to these prerequisites currently exist in §§ 50.55a(b)(2)(xviii)(D)(1) and 50.55a(b)(2)(xviii)(D)(2), the current provision paragraph does not make it clear that these alternatives are acceptable because it does not refer to them as options. Therefore, the NRC is proposing to clarify that the alternatives are acceptable to meet the requirement.

The NRC proposes to revise § 50.55a(b)(2)(xxv) to correct an error in the title. The current title of § 50.55a(b)(2)(xxv) incorrectly states “Section XV Condition.” This proposed change would correct the title to state “Section XI Condition.”

The NRC proposes to revise § 50.55a(b)(2)(xxviii) to clarify that the condition applies to A-4300(b)(1) for the ASME BPV Code, Section XI, 2021 Edition and earlier. For the 2023 Edition, this proposed change would clarify that the condition applies to Y-3100(c). In the 2023 Edition, ASME moved the fatigue crack growth law for ferritic steels in air from A-4300 to Y-3100. The existing condition in § 50.55a(b)(2)(xxviii) still applies to Y-3100.

The NRC proposes to revise § 50.55a(b)(2)(xxxi) to add several provisions related to the use of mechanical clamping devices. In the 2023 Edition of the ASME BPV Code, Section XI, Appendix W was revised to remove the prohibition on the use of mechanical clamps for Class 1 piping, portions of piping that form the containment boundary, piping larger than nominal pipe size (NPS) 2 with nominal operating temperature of 200 °F (95 °C) and nominal pressure of 275 pounds per square Inch gauge (psig) (1,900 kilopascal (kPa)), and piping larger than NPS 6 (DN 150). Note that Nonmandatory Appendix W was previously Code Case N-523 in the early 2000s, and was later incorporated into a mandatory appendix, and finally in the 2013 Edition of Section XI, was made into Nonmandatory Appendix W.

The existing § 50.55a(b)(2)(xxxi) condition specifies that when installing a mechanical clamping device on an ASME BPV Code class piping system, Appendix W of Section XI shall be treated as a mandatory appendix and all of the provisions of Appendix W shall be met for the mechanical clamping device being installed. Additionally, the second part of the condition specifies that use of IWA-4131.1(c) of the 2010 Edition of Section XI and IWA-4131.1(d) of the 2011 Addenda of the 2010 Edition and later versions of Section XI is prohibited on small item Class 1 piping and portions of a piping system that form the containment boundary. The change to Appendix W was not modified in a way that would make it possible for the NRC to remove this condition.

Additionally, the NRC proposes four new provisions to be added to the condition as follows:

• The prohibition in Appendix W for use on Class 1 piping was removed by ASME because it is not specified in the title of the Nonmandatory Appendix W. However, the NRC notes that this condition is to ensure that Class 1 is not applicable to this Appendix and will not be an oversight in future revisions. Further discussion of this included interpretations in other sections of ASME Code, that could allow use of mechanical clamps on Class 1 piping which was discussed in a final rule titled “Incorporation be Reference of American Society of Mechanical Engineers Codes and Code Cases” (82 FR 32934; July 18, 2017) that incorporated by reference the 2013 Edition of the ASME Code. Therefore, the NRC is proposing to include a condition that prohibits the use of Appendix W on Class 1 piping to provide clarity that the change in the ASME Code does not reflect a change in applicability of Appendix W to Class 1 piping.

• The prohibition in Appendix W for use on piping that forms part of the containment boundary was removed by the ASME based on NRC approval of alternative requests submitted using § 50.55a(z)(2). Although the NRC approved the use of Appendix W on a case-by-case basis on certain systems, the NRC has not allowed Appendix W to be used generically on an unlimited basis on numerous joints and systems that collectively could affect the function of the system. Requesting NRC approval through the § 50.55a(z) processes allows specific applications and limits the frequency on its use within each system as to ensure that the structural margin is maintained, thereby reducing the potential for challenging the structural integrity of the joints and system. Therefore, the NRC is proposing to include a condition that prohibits the use of Appendix W on piping that forms part of the containment boundary.

• The prohibition in Appendix W for use on piping larger than NPS 2 (DN 50) when the nominal operating temperature or pressure exceeds 200 °F (95 °C) or 275 psig (1,900 kPa) was removed. The NRC notes that the potential consequence of failure of a high-energy line piping limits the use of the mechanical clamps. High-energy lines can produce consequences that are severe and challenge the function of components and systems to safely shut down the reactor. Therefore, the NRC is proposing to include a condition that prohibits the use of Appendix W on piping larger than NPS 2 (DN 50) when the nominal operating temperature or pressure exceeds 200 °F (95 °C) or 275 psig (1,900 kPa), which maintains the previous prohibition in earlier editions of Appendix W.

• The prohibition in Appendix W for use on piping greater than NPS 6 (DN 150) was removed by the ASME based on NRC approval of one alternative request submitted using § 50.55a(z)(2). However, this approval was for a discharge line that did not affect the system's ability to perform its safety function of removing heat. Approving the use of Appendix W on a case-by-case basis on certain locations in systems does not allow it to be used generically on an unlimited basis on numerous joints and systems that collectively could affect the function of the system. The limitations on the frequency on its use within each system is to ensure that the structural margin is maintained, thereby reducing the potential for challenging the structural integrity of the joints. Therefore, the NRC is proposing to include a condition that prohibits the use of Appendix W on piping greater than NPS 6 (DN 150), which maintains the prohibition from earlier editions of Appendix W.

The NRC proposes to revise § 50.55a(b)(2)(xxxiv)(B) to extend the applicability of the condition to the 2023 Edition of ASME BPV Code, Section XI. This condition prohibits the use of Nonmandatory Appendix U, Supplement U-S1. The provisions of U-S1 are redundant to those in Code Case N-513. The purpose of § 50.55a(b)(2)(xxxiv)(B) is to clarify that the more up-to-date approach of Code Case N-513 is the appropriate method for temporary acceptance of flaws in moderate energy piping. This condition remains applicable to the 2023 Edition of the ASME BPV Code, Section XI.

The NRC proposes to revise § 50.55a(b)(2)(xliv) to correct errors, extend its applicability to the 2023 Edition of the ASME BPV Code, Section XI, and add one provision.

The current regulations in § 50.55a(b)(2)(xliv) incorrectly reference Subarticle Y-2440, when the correct reference is Subarticle Y-2400. The current regulations in § 50.55a(b)(2)(xliv) also incorrectly reference Articles Y-2200 and Y-3200, when the correct reference is Subarticles Y-2200 and Y-3200. This proposed revision would correct those errors.

The NRC imposed § 50.55a(b)(2)(xliv) on the 2021 Edition of the ASME BPV Code, Section XI, because the crack growth laws in Subarticles Y-2200, Y-2400, and Y-3200 are duplicated in Code Cases N-809, N-889, and N-643, respectively. The purpose of § 50.55a(b)(2)(xliv) is to eliminate duplication and clarify that the code cases should govern. § 50.55a(b)(2)(xliv) remains applicable to the 2023 Edition of the ASME BPV Code, Section XI.

ASME added crack growth laws for nickel alloys to Article Y-4000 in the 2023 Edition of the ASME BPV Code, Section XI. In particular, ASME added factors of improvement for Alloys 690, 52, 152, and variant welds in paragraph Y-4322. The rules added to paragraph Y-4322 are duplicated in Code Case N-909. The NRC's position is that the relevant code case should govern whenever there are overlapping requirements between the ASME BPV Code and a code case. Therefore, the NRC is proposing to add § 50.55a(b)(2)(xliv)(D) to prohibit use of paragraph Y-4322.

The NRC proposes to revise § 50.55a(b)(2)(xlv) to extend the applicability of the condition through the latest edition of the ASME BPV Code, Section XI incorporated by reference in paragraph (a)(1)(ii). The 2023 Edition of Section XI was not updated to include the provisions of this condition. Therefore, the NRC is proposing to revise this condition to apply to the latest edition incorporated by reference.

The NRC proposes to revise § 50.55a(b)(2)(xlvi) to extend the applicability of the condition through the latest edition of the ASME BPV Code, Section XI incorporated by reference in paragraph (a)(1)(ii). The 2023 Edition of Section XI was not updated to include the provisions of this condition. Therefore, the NRC is proposing to revise this condition to apply to the latest edition incorporated by reference.

The NRC proposes to revise § 50.55a(b)(2)(xlviii) to extend the applicability of the condition through the latest edition of the ASME BPV Code, Section XI, incorporated by reference in paragraph (a)(1)(ii), and make an editorial correction. This condition requires that licensees submit to the NRC analytical evaluations performed under ASME BPV Code, Section XI, IWB-3132.3 and IWC-3122.3. The original requirements to submit these evaluations previously resided in ASME BPV Code, Section XI, IWB-3134 and IWC-3125. ASME removed these requirements in the 2019 Edition of ASME BPV Code, Section XI. The current reference for ASME Class 2 analytical evaluation is incorrectly referenced as IWC-3132.3 versus the correct reference of IWC-3122.3. As an editorial change, the reference has been updated. This condition remains applicable to the 2023 Edition of ASME BPV Code, Section XI.

The NRC proposes to add condition § 50.55a(b)(2)(li) to prohibit the use of IWA-4540(d)(7) in the 2023 Edition of the ASME BPV Code, Section XI, for exempting pressure testing of Class 2 and 3 welds that have a surface or volumetric examination performed. Current ASME Code requirements specify a pressure test of most welds regardless of the non-destructive examination performed. The current exemptions for pressure testing are for welds in components or connections NPS 1 (DN 25) or smaller and other miscellaneous welds such as tube‐to‐tubesheet welds and seal welds. ASME added IWA-4540(d)(7) in the 2023 Edition of ASME BPV Code, Section XI, exempting pressure testing of Class 2 and 3 welds that are examined by a volumetric or surface examination following repair/replacement.

An ASME Code pressure test, with or without NDE, after a repair/replacement activity is needed to ensure the ASME Class 2 and 3 system, including emergency core cooling systems, would be able to perform its intended function to safely shut down and maintain the reactor in a safe condition. In addition, a pressure test is a defense-in-depth measure, supplementing any surface or volumetric NDE conducted, even as required by the Construction Code. The purpose of the pressure test, in this role, is to address the possible uncertainty associated with various NDE techniques. In addition, operational experience has shown pressure tests identify flaws that were not revealed by volumetric and surface examinations. Leakage from a component immediately after being repaired indicates a quality issue that must be addressed. The NRC position is that a pressure test should be conducted in addition to any surface or volumetric NDE required on a repaired or replaced ASME Class 2 or 3 component. Therefore, the NRC is proposing to add § 50.55a(b)(2)(li) to condition provisions IWA-4540(d)(7) of the 2023 Edition of the ASME Code, Section XI, to prohibit the exemption of performing a pressure testing for Class 2 and 3 welds that have had a surface or volumetric examination performed.

The NRC proposes to add condition § 50.55a(b)(2)(lii) to require preservice and inservice volumetric examination of nozzles fabricated from weld buildups specified in Figure IWB-2500-7(d) of the 2023 Edition of the ASME BPV Code, Section XI. ASME changed Figure IWB-2500-7(d) in the 2023 Edition to allow nozzles fabricated by weld buildups to be installed without preservice or inservice examinations throughout the life of the component. Nozzles fabricated by weld buildup have multiple weld passes, which each provide an opportunity for flaws to be located within the weld buildup. These flaws could propagate during service and could cause component failure.

Currently, nozzles fabricated from weld buildups, such as in the AP1000 design, are required to have a preservice and inservice volumetric examination performed. This condition would be consistent with current requirement for AP1000 design which consists of a volumetric examination (ultrasonic) of weld buildups and are performed with procedures and personnel to the ASME BPV Code, Section XI, Appendix VIII using acceptance criteria of IWB-3514 for Category B-F welds in the ASME BPV Code, Section XI. Therefore, the NRC is proposing to add § 50.55a(b)(2)(lii) to condition provisions in Figure IWB-2500-7(d) of the 2023 Edition of the ASME BPV Code, Section XI, to require preservice and inservice volumetric examination of nozzles fabricated from weld buildups. This maintains the requirements from previous editions of the Code. The volumetric examination (ultrasonic) of weld buildups shall be performed with procedures and personnel to the ASME BPV Code, Section XI, Mandatory Appendix VIII using acceptance criteria of IWB-3514 for Category B-F welds in the ASME BPV Code, Section XI.

The NRC proposes to add condition § 50.55a(b)(2)(liii) to require that reasonable protection from deterioration of radiographic film specified in IWA-6310(b) of the 2023 Edition of the ASME BPV Code, Section XI, shall include the provisions in IWA-6320 and the reproduction must be retained as a lifetime record in accordance with IWA-6330, IWA-6340, and IWA-6350 of the ASME BPV Code, Section XI.

IWA-6300 requires final radiographic film to be maintained as a lifetime record in accordance with IWA-6330, IWA-6340, and IWA-6350 of the ASME BPV Code, Section XI. In the 2023 Edition, ASME added IWA-6310(b), which specifies that film deteriorates and therefore need not be maintained. While IWB-6310(b) specifies that reasonable protection from deterioration for radiographic film shall be provided, it also states that deterioration of radiographic film is to be expected and is not a violation of the requirement to provide suitable protection. The new provision further states that if radiographic film has deteriorated, it need no longer be maintained as a lifetime record, as determined by the owner.

However, the NRC notes that there are existing provisions in IWA-6320 that allow reproduction of radiographic film, including by electronic processes ( e.g., digitize) before the original film's deterioration. Therefore, the NRC is proposing to add § 50.55a(b)(2)(liii) to condition provision IWA-6310(b) of the 2023 Edition of the ASME BPV Code, Section XI, to require that the reasonable protection from deterioration of radiographic film shall include the provisions specified in IWA-6320, and the reproduction must be retained as a lifetime record in accordance with IWA-6330, IWA-6340, and IWA-6350. This would maintain the current requirements in the 2021 Edition of the ASME BPV Code, Section XI.

A similar condition, § 50.55a(b)(1)(xv), is proposed in this rule for Table NCA-4134.17 of the ASME BPV Code, Section III.

The NRC proposes to revise § 50.55a(g)(6)(ii)(D)(9) to allow for qualification of volumetric evaluation in accordance with Section XI, Division 1, Mandatory Appendix VIII, Supplement 15, in the 2021 Edition through the latest edition and addenda incorporated by reference in paragraph (a)(1)(i) of this section. Licensees have the option to use the latest version of Supplement 15 in lieu of the requirements of Code Case N-729-6. The proposed change would allow licensees to utilize the 2023 Edition of Supplement 15 as an option to the volumetric qualification requirements of Code Case N-729-6.

The NRC proposes to revise § 50.55a(g)(6)(ii)(F)(2)(iv) to include inspection item B-3 in the list of categorization options for identification of cold leg temperature welds. Inspection item B-3 (auxiliary head adapter butt welds) was previously part of inspection item B-1. This proposed revision maintains the same requirements and only clarifies the expansion of categorization options for licensees for auxiliary head adapter butt welds.

The NRC proposes to revise § 50.55a(g)(6)(ii)(F)(13) to include inspection item B-3 in the list of encoded volumetric exams. Inspection item B-3, auxiliary head adapter butt welds, was previously part of inspection item B-1. This proposed revision maintains the same requirements for encoded volumetric exams.

This proposed rule would incorporate by reference the latest revisions of the NRC's RGs that list the ASME BPV and OM Code Cases that the NRC finds to be acceptable, or acceptable with NRC-specified conditions (“conditionally acceptable”). RG 1.84, Revision 41 (DG-1446) would supersede the incorporation by reference of Revision 40; RG 1.147, Revision 22 (DG-1447) would supersede the incorporation by reference of Revision 21; and RG 1.192, Revision 6 (DG-1448) would supersede the incorporation by reference of Revision 5.

The ASME BPV Code Cases that are the subject of this proposed rule are the new and revised Section III and Section XI Code Cases as listed in Supplements 3 through 6 to the 2021 Edition of the ASME BPV Code and Supplements 0 through 3 to the 2023 Edition of the ASME BPV Code. By letter dated October 18, 2024, ASME requested that the NRC consider including, in part, Code Cases N-752-2, N-926 and N-934 in this proposed rulemaking. In response, the NRC included these three code cases within the scope of this proposed rule. The NRC also is proposing to include OMN-32, Revision 1, “Alternative Requirements for Range and Accuracy of Pressure, Flow, and Differential Pressure Instruments Used in Pump Tests,” and OMN-34, “Use of Pump Curve Testing,” within the scope of this proposed rule.

The ASME publishes code cases that provide alternatives to existing code requirements that the ASME developed and approved. This proposed rule would incorporate by reference the most recent revisions of RGs 1.84, 1.147, and 1.192, which allow nuclear power plant licensees, and applicants for combined licenses, standard design certifications, standard design approvals, and manufacturing licenses under the regulations that govern license certifications, to use the code cases listed in these RGs as suitable alternatives to the ASME BPV and OM Codes for the construction, inservice inspections, and inservice testing of nuclear power plant components. The ASME makes the issued OM Code Cases available on the OM Code website and provides an index listing the issued OM Code Cases and their applicability in each ASME OM Code edition. The ASME publishes BPV Code Cases in a separate document and at a different time than the ASME BPV Code Editions. This proposed rule identifies the ASME BPV Code Cases by the edition of the ASME BPV Code under which they were published by the ASME and the OM Code Cases by the most recent edition of the ASME OM Code to which they apply.

The following general guidance applies to the use of the ASME Code Cases approved in the latest versions of the RGs that are incorporated by reference into § 50.55a as part of this proposed rule. Specifically, the use of the code cases listed in the latest versions of RGs 1.84, 1.147, and 1.192 are acceptable with the specified conditions when implementing the editions and addenda of the ASME BPV and OM Codes incorporated by reference in § 50.55a.

The approval of a code case in these RGs constitutes acceptance of its technical position for applications that are not precluded by other requirements. The applicant or licensee is responsible for ensuring that use of the code case does not conflict with regulatory requirements or licensee commitments. The code cases listed in the RGs are acceptable for use within the limits specified in the code cases. If the RG states an NRC condition on the use of a code case, then the NRC condition supplements and does not supersede any limitation(s) specified in the code case, unless otherwise stated in the NRC condition.

The ASME Code Cases may be revised for many reasons ( e.g., to incorporate operational examination and testing experience or to update material requirements based on research results). On occasion, an inaccuracy in an equation is discovered or an examination, as practiced, is found not to be adequate to detect a newly discovered degradation mechanism. Therefore, when an applicant or a licensee initially implements a code case, § 50.55a requires that the applicant or the licensee implement the most recent version of that code case, as listed in the RGs incorporated by reference. Code cases superseded by revision are no longer acceptable for new applications unless otherwise indicated.

Section III of the ASME BPV Code applies to new construction ( e.g., the edition and addenda to be used in the construction of a plant are selected based on the date of the construction permit and are not changed thereafter, except voluntarily by the applicant or the licensee). Section III also may be used for repair and replacement activities under the provisions of Section XI of the ASME BPV Code. Whether used for construction or later repair or replacement, when a code case is first implemented by a licensee, the applicant implements the latest edition incorporated by reference into § 50.55a. Thereafter, the applicant or licensee may continue to apply the previously implemented version of the code case or may apply the later version of the code case, including any NRC-specified conditions placed on its use.

Code cases apply to specific editions and addenda, and code cases may be revised for various reasons. Licensees that were using a code case before the effective date of a final rule incorporating by reference a regulatory guide in § 50.55a(a)(3) may continue to use the previous version until the next update to the code of record for the ISI or IST program, as applicable. This relieves licensees of the burden of having to update their ISI or IST program each time a code case is revised by the ASME and approved for use by the NRC. The rules for applying code cases are described in §§ 50.55a(b)(4), 50.55a(f)(4), and 50.55a(g)(4).

The ASME may annul code cases that are no longer required, are determined to be inaccurate or inadequate, or have been incorporated into the ASME BPV or OM Codes. A code case may be revised, for example, to incorporate user experience. The older or superseded version of the code case cannot be applied by the licensee or applicant if it is the first use of that code case. If an applicant or a licensee applied a code case before it was listed as superseded or annulled, the applicant or the licensee may continue to use the code case until the applicant or the licensee updates its Construction Code of record (or updates its application, in the case of an applicant) or until the licensee's code of record interval for the ISI or IST program expires, after which the continued use of the code case is prohibited unless NRC authorization is given under § 50.55a(z). If a code case is incorporated by reference into § 50.55a and later a revised version is issued by the ASME because experience has shown that the design analysis, construction method, examination method, or testing method is inadequate, the NRC will amend § 50.55a and the relevant RG to remove the approval of the superseded code case. Applicants and licensees should not begin to implement such superseded code cases in advance of the rulemaking.

The code cases discussed in Table 2 are new, revised, or reaffirmed code cases in which the NRC is not proposing any conditions. The table identifies the draft regulatory guide listing the applicable code case that the NRC proposes to approve for use.

The NRC has determined that certain code cases, as issued by the ASME, are generally acceptable for use, but that the alternative requirements specified in those code cases must be supplemented in order to provide an acceptable level of quality and safety. Accordingly, the NRC proposes to impose conditions on the use of these code cases to modify, limit, or clarify their requirements. The conditions would specify, for each applicable code case, the additional activities that must be performed, the limits on the activities specified in the code case, and/or the supplemental information needed to provide clarity. These ASME Code Cases, listed in Table III, are included in Table 2 of DG-1447 (RG 1.147) and DG-1448 (RG 1.192). This section provides the NRC's evaluation of the code cases and the reasons for the NRC's proposed conditions. Notations indicate the conditions duplicated from previous versions of the RG.

The NRC requests public comment on these code cases and the proposed conditions. It also should be noted that this section only addresses those code cases for which the NRC proposes to impose condition(s), which are listed in the RG for the first time.

Type: Revised.

Title: Rotation of Snubbers and Pressure Retaining Items for the Purpose of Testing or Preventive Maintenance.

Code Case N-508 describes the circumstances under which items may be rotated from stock for routine maintenance and testing without following all the repair/replacement rules of IWA-4000. In Revision 5 of the code case, ASME removed a prescriptive list of items and replaced it with “pressure retaining items” This change allows the code case to be applied to a broader range of components, such as valves and heat exchangers, that may be similarly rotated from stock. While the NRC has no objection to the broader application of this code case as allowed in Revision 5, the existing condition on Code Case N-508-4 remains applicable. Therefore, the NRC proposes to approve Code Case N-508-5 and retain the existing condition.

Type: Revised.

Title: Weld Overlay of Class 1, 2, and 3 Socket Welded Connections.

Code Case N-666 provides an alternative to the defect removal provisions of IWA-4420 by installation of weld overlay for restoring structural integrity of a cracked or leaking socket weld if a failure is a result of vibration fatigue. N-666-1 is currently listed in Table 2 of RG 1.147 as conditionally acceptable for use. Revision 2 extended the applicability of the code case to dissimilar metal socket welds, addressed the NRC condition regarding surface examination after installation of the weld overlay on Class 1 and Class 2 piping socket welds, deleted the prohibition on welding on water backed P-No. 1 Group 2 materials with a carbon content greater than 0.30 percent, and removed filler metal requirements. Revision 3 of the code case superseded revision 2 and specified applicability to tubing socket welds and removes NIS-2 Form documentation requirements.

In revision 2 of the code case, ASME added P-43 base materials and dissimilar welds between P-No. 1 and P-No. 8, between P-No. 8 and P-No. 43, and between P-No. 1 and P-No. 43. P-No. 43 base materials are Ni-Cr-Fe materials such as Alloys 600 and 690. The NRC finds the addition of P-No. 43 material and dissimilar metal welds is acceptable because the mechanical fatigue characteristics of nickel-based alloys and their associated filler materials are expected to be similar to that of stainless steel, which was listed as approved in Code Case N-666-1.

In revision 3 of the code case, ASME added the terms “tube” and “tubing” in relevant sections to explicitly allow for weld overlay repair of tubing socket welds. Moreover, the revision included the deletion of the section requiring documenting the code case on an NIS-2 Form. This section was deemed redundant and unnecessary, as IWA-6211(d) already mandates the documentation of all repair/replacement activities on this form. The NRC finds these revisions to be acceptable.

The current condition on N-666-1 in Regulatory Guide 1.147, Revision 21, states that the licensee must perform a surface examination and disposition the results according to the construction code. ASME modified the provisions of 5(a)(1) of the code case to require such examination and disposition of results. The NRC finds this change to be acceptable and proposes to remove the existing condition for Code Case N-666-3.

ASME modified the provisions of 1(b) of the code case to remove the limitation against water backed welding of P-No. 1 Group 2 materials with a carbon content greater than 0.30 percent. The NRC has approved alternative requests for welding P-No. 1 Group 2 materials with a carbon content up to 0.35 percent (ML20111A337). However, the use of low hydrogen electrodes when applying the shielded metal arc welding (SMAW) process and the use of stringer beads were part of the basis for approval, since this welding approach limits the potential for hydrogen induced cracking. Therefore, the NRC proposes to add a condition to Code Case N-666-3 requiring that only stringer beads (no weaving) be used, and that when using the SMAW process, low hydrogen electrodes are used when welding P-No. 1 Group 2 materials with carbon content greater than 0.30 percent.

ASME deleted the listing of American Welding Society filler metal classifications to be used. The NRC finds this change acceptable because the code case requires that welding procedure specifications must be qualified in accordance with the ASME BPV Code Section XI, IWA-4440, which in turn references ASME BPV Code, Section IX. This ensures that welding filler materials used are compatible with the base materials and weld materials over which the weld overlay is applied. However, as noted above, when the SMAW process is used, the NRC proposes to require low hydrogen electrodes when welding materials with a carbon content greater than 0.30 percent carbon.

Type: Revised.

Title: Alternative Classification and Examination Requirements.

Code Case N-716 provides requirements for risk-informed classification and examination for Class 1 piping welds, Class 2 components, Class 3 components, or non-class components. Code Case N-716-3 is listed in Regulatory Guide 1.147, Revision 21, as acceptable for use with the condition that it is not approved for use by plants issued an operating license or combined license after January 1, 2012. In revision 4 of the code case, the ASME modifies the successive examination requirements for items with multiple degradation mechanisms in cases where an initial examination has revealed flaws or relevant conditions exceeding the acceptance standards of Section XI Article IWB-3000, Article IWC-3000, or Article IWD-3000, as applicable. In Code Case N-716-3, all welds were assigned different possible degradation mechanisms, such as fatigue cracking, stress corrosion cracking, or no degradation mechanism. If an item was subject to multiple degradation mechanisms, all applicable degradation mechanisms were listed for the item. If a flaw was found during examination activities, the owner determined the damage mechanism. In Code Case N-716-3, the expanded scope for additional examinations included inspection items with the same postulated degradation mechanism and the combination of degradation mechanisms. In revision 4 of the code case, the ASME limited the scope of the additional examinations to include only those items with the same combination of degradation mechanisms.

The NRC proposes to maintain the condition imposed on Code Case N-716-3, as the code case was not modified to address the condition. The NRC position is that there are enough variables possible in the design of new reactors that the NRC should review the proposed degradation mechanisms and risk related information for new plants before application of the code case. Regarding the revision to the scope expansion rules, the NRC objects to the option of limiting the scope expansion to only those locations classified according to the same degradation combination, because an insufficient technical basis was provided to show that this method would be effective in assessing the true extent of condition. The proposed Condition 2 would preserve the wording on Section 6, “Successive Inspections and Additional Examinations,” sub-paragraphs (b)(1)(-b) and (b)(1)(-c), from Code Case N-716-3.

Type: Revised, no current NRC position.

Title: Risk-Informed Categorization and Treatment for Repair/Replacement Activities in Class 2 and 3 Systems.

Code Case N-752 provides a process for determining the risk-informed categorization and treatment for repair/replacement activities on Class 2 and 3 items that are categorized as low safety significant. Revision 1 of the code case provided clarification on the scope of the code case. Revision 2 of the code case focused categorization and safety evaluation on items versus systems, clarified requirements for supports, removed requirements for probabilistic risk assessment (PRA) updates, allowed a piping segment to be a single item, provided an additional option to verify technical adequacy of the PRA, removed the requirements to consider external events such as seismic, and added a new footnote to clarify no optionally Class 1 or Class 1 exempt item can be categorized by this case before reclassification as non-Class 1 in accordance with the applicable change control process. The NRC has not previously issued a position on Code Cases N-752 or N-752-1. The NRC has reviewed Code Case N-752-2 and determined it to be acceptable for use, with conditions as specified in RG 1.147.

The NRC proposes to add a condition that the owner shall review changes to the plant, operational practices, applicable plant and industry operational experience, and, as appropriate, update the PRA and categorization and treatment processes, and that the owner shall perform this review in a timely manner but no longer than once every two refueling outages. Consistent with plant-specific Code Case N-752 relief request approvals, a review of the plant PRA must be completed in a timely manner because the periodic update of the plant PRA may affect the results of the categorization process. The validity of the categorization process relies on ensuring that the performance and conditions of structures, systems, and components (SSCs) continue to be maintained consistent with applicable assumptions. Changes in the level of treatment applied to an SSC might result in changes in the reliability of SSCs credited in the categorization process. These changes along with modifications to the plant, operational practices and experiences should be reflected in the PRA on a consistent basis to ensure accuracy and credibility of categorization results.

In approving the use of Code Case N-752-2, the NRC specifies that Subparagraph-1420 from IWA-1400(o) does not relieve licensees of obligations to document quality assurance programs or otherwise affect NRC requirements for quality assurance outside of § 50.55a ( e.g., Appendix B to 10 CFR part 50 and § 50.54(a)). Footnote 1 in Code Case N-752-2 states that if compliance with 10 CFR part 50, Appendix B, “Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants,” or ASME Standard NQA-1, “Quality Assurance Requirements for Nuclear Facility Applications,” is required at the owner's facility, then IWA-1400(o) in ASME BPV Code, Section XI, Division 1, is not exempt. This language in Code Case N-752-2 and earlier versions caused confusion among nuclear power plant licensees regarding the applicability of 10 CFR part 50, Appendix B, when implementing Code Case N-752. The NRC resolved this confusion in NRC Information Notice 2025-01, “Lessons Learned When Implementing ASME Code Case N-752,” by stating that licensees are required to comply with the quality assurance requirements in 10 CFR part 50, Appendix B, for safety-related Class 2 and Class 3 low safety significant items. Information Notice 2025-01 notes that the NRC has approved specific changes to the Quality Assurance Program Descriptions related to the implementation of Code Case N-752. For early uses of Code Case N-752, licensees followed § 50.54(a)(4) to establish risk-informed supplemental processes and procedures that the NRC accepted as satisfying the requirements of 10 CFR part 50, Appendix B, given the low safety significance of the components within the scope of Code Case N-752. For later adoptions of Code Case N-752, licensees followed § 50.54(a)(3) to apply risk-informed quality assurance treatment of components within the scope of Code Case N-752. The NRC regulations in § 50.54(a)(3) allow licensees to adjust their quality assurance activities as accepted by the NRC in response to prior licensee requests under § 50.54(a)(4). Therefore, licensees are encouraged to review prior licensee requests under § 50.54(a)(4) to determine the extent of the risk-informed quality assurance treatment for components within the scope of Code Case N-752 allowed under § 50.54(a)(3).

In approving the use of Code Case N-752-2, the NRC also specifies that for a supporting requirement to be met, all relevant peer review and other independent findings shall have been addressed and necessary changes made to PRA models, methods, and documentation. In addition, all relevant peer review facts and observations (F&Os) findings for the internal events and internal flooding PRA shall have been dispositioned and closed out using an acceptable process. Examples of NRC-endorsed processes for these activities include NEI 17-07 Revision 2 and Appendix X to NEI 05-04/7-12/12-06. A peer review of the PRA is performed to determine whether the requirements established in national consensus PRA standards, as endorsed by the NRC with exceptions and clarifications, have been met. To remove the need for NRC review of plant-specific PRAs in support of Code Case N-752-2, all relevant peer review findings must be closed using an acceptable close-out process. An acceptable close-out process includes NEI 17-07 Revision 2, as endorsed by the NRC in RG 1.200, “Acceptability of Probabilistic Risk Assessment Results for Risk-Informed Activities,” Revision 3, Regulatory Position C.2.2. Another acceptable close-out process includes NEI 05-04/07-12/12-06, Appendix X: “Close-Out of Facts and Observations (F&Os),” dated February 21, 2017, as accepted by NRC by letter dated May 3, 2017. The implementation of an acceptable closure process is intended to provide the needed confidence in the resolution of peer review F&Os against the requirements in the national consensus PRA standard such that, when used in support of Code Case N-752-2, it will remove the need for an in-depth review of the licensee's F&O resolutions by NRC reviewers.

The NRC issued a policy statement on the use of PRA methods in NRC activities in the Federal Register on August 16, 1995. The NRC's 1995 Policy Statement on the use of PRA states that the use of PRA technology should be increased to the extent supported by the state-of-the-art in PRA methods and data and in a manner that complements the NRC's deterministic approach. Since the NRC issued its PRA policy statement, a number of risk-informed regulatory activities have been implemented and necessary technical documents developed to provide guidance on the use of PRA information. This guidance includes RG 1.200, which describes one acceptable approach for determining the requisite technical adequacy of the PRA is sufficient to provide confidence in the results. The RG revisions reference successive consensus PRA standards developed by the ASME and the American Nuclear Society (ANS). RG 1.200, Revision 1, references ASME RA-S-2002-2002, ASME RA-Sa-2003 and ASME RA-Sb-2005 standards; and RG 1.200, Revisions 2 and 3, references ASME/ANS RA-Sa-2008 and ASME/ANS RA-Sa-2009 standards. Furthermore, in March 2007, the NRC issued Regulatory Issue Summary (RIS) 2007-06, “Regulatory Guide 1.200 Implementation” which states “the NRC would expect licensees to fully address all scope elements consistent with Revision 2 of RG 1.200 by the end of 2009.” Because of regulatory and industry initiatives, the majority of the U.S. nuclear fleet currently have peer reviewed PRAs that show conformance to RG 1.200, Revision 2. The NRC finds the technical adequacy of the base PRA, as determined by RG 1.200, Revision 1, to be sufficient with regard to use of Code Case N-752-2 to provide the needed confidence in the results. In alignment with the NRC's policy statement on the use of PRA, RIS 2007-06 and the status of PRAs for the U.S. nuclear fleet, the licensee also may elect to use RG 1.200, Revision 2, or RG 1.200, Revision 3, to ensure the technical adequacy of the PRA by meeting supporting requirements that correspond to supporting requirements in RG 1.200, Revision 1. This can include full-scope peer review of internal events and internal flooding PRA against RG 1.200, Revision 2, as well as a gap assessment of earlier peer reviews of the internal events and internal flooding PRA against RG 1.200, Revision 2. The NRC reviewed the requirements of Table I-7 and concluded that the corresponding supporting requirements endorsed in RG 1.200, Revision 2 and Revision 3, are adequate to meet the requirements of Table I-7 for technical adequacy of the PRA. Therefore, the NRC determined that licensee PRA programs that conform to RG 1.200, Revision 2 or Revision 3, would meet the requirements of N-752-2 as incorporated by reference in RG 1.147.

The NRC considered internal flooding supporting requirements for inclusion in Table I-7 of Code Case N-752-2, consistent with requirements for Code Case N-716-1, “Alternative Classification and Examination Requirements Section XI, Division 1,” Mandatory Appendix 2, as endorsed in RG 1.147. The NRC evaluated the difference in supporting requirements and concluded the methodology as outlined in Section I-3.3.1, “Modes and Effects Analysis,” part (c), “Indirect Effects,” adequately addresses spatial effects, as defined in the glossary, to include flooding as part of the consequence evaluation.

The NRC considered whether a qualitative assessment should be performed to adjust the consequence rank to reflect the pressure boundary's failure impact on the mitigation of external events. The NRC determined that the baseline risk from external events would have a minimal influence on the categorization results, which already assume complete loss of the pressure retaining item and which are primarily driven by the availability and reliability of mitigating systems responding to direct and indirect effects of the item's failure. This NRC evaluation is consistent with feedback from industry stakeholders, licensees in public meetings, and audit discussions related to passive categorization.

Type: Revised.

Title: Alternative Requirements for Preparation and Submittal of Plans, Schedules, and Preservice and Inservice Inspection Summary Reports.

Code Case N-778 offers alternatives to the requirements of IWA-1400(c) and IWA-6240 for the preparation and submission of various inspection reports and plans. In revision 1 of the code case, the ASME modified the submission period for the inservice inspection summary report to the NRC from 90 days to 120 days. The NRC does not object to allowing licensees more time to prepare and submit the report.

Code Case N-778-1, paragraph (d), states that “Plans, schedules, and preservice and inservice inspection summary reports shall be submitted to the enforcement and regulatory authorities having jurisdiction at the plant site, if required by these authorities.” The existing conditions on Code Case N-778 specify that the preservice inspection and inservice inspection summary reports shall be submitted to the NRC and the timing of such submissions. Since the code case still qualifies the requirement with “if required by these authorities,” the NRC proposes to retain the existing condition.

Type: Revised.

Title: Analytical Evaluation of Metal Loss in Class 2 and 3 Metallic Piping Buried in a Back-Filled Trench.

Code Case N-806 provides guidelines for assessing metal loss in ASME Code Class 2 and 3 buried piping items, using data obtained from inspection results. ASME revised this code case from N-806-1 based on the NRC's comments. Revision 2 of the code case enhances methods for flaw evaluation utilizing internal pressures, soil and surcharge loads, and seismic loads. The main revision expands the analytical evaluation framework to include Level 3 evaluations for seismic impacts on buried piping as specified in the code case. Code Case N-806-2 is not applicable to cast iron, leakage through a piping item or joint, cracked piping items, non-metallic piping with or without a metallic liner, and piping items with a minimum wall thickness of less than 0.1 inch (.25 cm).

Equation 16 of Section 6.2.2.2(c) is related to the buckling of the buried pipe under external pressure. The existing Equation 16 requires that P ss ′ ≤ P cr /2, where P ss ′ is the total external pressure plus negative internal pressure, P cr is the critical buckling pressure of the buried pipe, and “2” is the structural factor. The NRC notes that Equation 16 for buckling due to external pressure is similar to the buckling equation used in American Lifelines Alliance, “Guidelines for the Design of Buried Steel Pipe,” July 2001 with Addenda through February 2005; NUREG/CR-6876, “Risk-Informed Assessment of Degraded Buried Piping System in Nuclear Power Plants”; and A.P. Moser, Buried Pipe Design, Second Edition, McGraw-Hill. However, the code case uses a structural factor of 2 in Equation 16 while these three references recommend a higher structural factor of 2.5 (when C/D = 2) or 3.0 (when C/D < 2), where C/D is soil depth to pipe diameter ratio. Therefore, the NRC proposes to approve Code Case N-806-2, with one condition to require the higher structural factors.

Type: Revised.

Title: Direct Use of Fracture Toughness for Flaw Evaluations of Pressure Boundary Materials in Class 1 Ferritic Steel Components.

Code Case N-830 defines fracture toughness models based on the Master Curve Method in accordance with ASTM E1921, “Standard Test Method for Determination of Reference Temperature, T 0 , for Ferritic Steels in the Transition Range,” that may be used in lieu of those specified in the ASME BPV Code, Section XI, Nonmandatory Appendices A, G, and K.

The current condition on N-830 in Regulatory Guide 1.147, Revision 21, states that the use of Paragraph (f) in N-830 is prohibited. In revision 1, ASME significantly revised and restructured this code case, including a different transition temperature toughness curve. Since the condition on the use of Paragraph (f) in N-830 applies to the transition temperature toughness curve defined in N-830, this existing condition is no longer applicable to the transition temperature toughness curve defined in revision 1. Therefore, the NRC proposes to remove the existing condition for Code Case N-830-1.

The NRC extensively reviewed Code Case N-830-1 while it was under development. During the review, the NRC evaluated relevant aspects of the fracture toughness models, including assumptions, datasets, uncertainties and biases, limitations, and applicability. The NRC generated over 40 comments to which the ASME Working Groups provided responses. The NRC reviewed all responses and determined that they adequately addressed the NRC's comments on the fracture toughness models. During its review, the NRC also performed an independent analysis of the fracture toughness models in the code case to confirm the validity of the models for materials with low upper shelf energy. The NRC confirmed that, where appropriate, the code case and technical basis document were updated as a result of the NRC's review.

Code Case N-830-1 specifies that the transition reference temperature be adjusted to account for effects of irradiation and notes that the methods in ASTM Standard E900-15, “Standard Guide for Predicting Radiation-Induced Transition Temperature Shift in Reactor Vessel Materials,” may be used for this adjustment. The NRC noted that while the methodology in ASTM E900-15 for calculating the transition reference temperature shift is currently not in the regulations nor endorsed by the NRC through a regulatory guide, it has been used in a recent NRC final report titled “Impacts of Embrittlement on Reactor Pressure Vessel Integrity from a Risk-Informed Perspective,” and in SECY-22-0019, “Rulemaking Plan for the Revision of Embrittlement and Surveillance Requirements for High-Fluence Nuclear Power Plants in Long-Term Operation.” Accordingly, the NRC proposes to condition Code Case N-830-1 to limit the methodology for determining the transition reference temperature shift due to irradiation effects to a methodology acceptable to the NRC, specifically Regulatory Guide 1.99, Revision 2, “Radiation Embrittlement of Reactor Vessel Materials,” including appropriate conversion factors and margins.

Type: New.

Title: Alternative Examination Requirements for Unbonded Post-Tensioning Systems of Class CC Components, Section XI, Division 1.

Code Case N-926 provides an alternative examination schedule for unbonded post-tensioning systems in Class CC containment structures. The alternative applies to tendon groups that have completed the required examinations at 20 years following the Structural Integrity Test and have met additional criteria demonstrating long-term structural integrity. Use of the alternative must be discontinued if the specified criteria are not satisfied.

The NRC has reviewed Code Case N-926 and determined that it provides an acceptable level of quality and safety for unbonded post-tensioning systems of Class CC components in containment structures, consistent with the provisions of § 50.55a(z)(1). The code case allows for a reduced testing frequency for tendon groups with a demonstrated history of satisfactory performance. Continued use of the alternative requires that test results remain within acceptable limits and that tendon force predictions show adequate margins through the next scheduled examination. In addition, the code case retains the existing requirement for five-year visual inspections of tendon assemblies. If these visual inspections identify degradation that may impact tendon performance, corrective actions, including tendon testing, may be necessary. The NRC's evaluation is further supported by operating experience from several previously approved relief requests that authorized similar reductions in tendon testing frequency. These approvals were based on demonstrated long-term performance and structural integrity of the tendon systems. This consistent operating experience reinforces the conclusion that the alternative examination schedule proposed in Code Case N-926 maintains an acceptable level of quality and safety.

However, Code Case N-926 does not explicitly address tendons that have undergone repair or replacement. To ensure consistent safety standards, the NRC is proposing that the alternative requirements of Code Case N-926 shall be applied to tendons affected by repair/replacement activities only if examinations of those affected tendons required by IWL-2521.2 at 20 years following tendon repair/replacement activities have been completed and all requirements specified in the “Scope” paragraph of Code Case N-926 have been met.

Type: New.

Title: Alternative Experience Requirements for Nondestructive Examination Personnel for Ultrasonic Examination.

Code Case N-930 provides qualification requirements related to ultrasonic examination personnel as part of the broader set of criteria and standards outlined in the ASME BPV Code, Section XI. The code case introduces alternative experience requirements for the qualification of ultrasonic examination personnel, specifically for Levels II and III. This code case presents an alternative to ASME BPV Code, Section XI, Mandatory Appendix VII, Table VII-4100, accommodating the challenges of reduced refueling outage durations and the application of risk-informed inservice inspection programs.

While Table VII-4100 has minimum experience requirements for personnel to be certified as ASME Levels I and II Ultrasonic (UT) personnel, notes (c) and (d) of the table allow for substitution of laboratory practice for all of the Level I experience hours and reduces the experience hours for Level II from 800 experience hours to 400 total hours, 320 of which can be laboratory practice. Notes (c) and (d) were added in the 2011 Addenda to the 2010 Edition of ASME BPV Code, Section XI. As there was not a sufficient technical basis for the reduction of hours and the substitution of laboratory practice, the NRC held the requirements of the 2010 Edition via the condition in § 50.55a(b)(2)(xviii)(D).

The NRC conducted research into the substitution of laboratory practice hours for experience hours. This work was published in the technical letter report “Nondestructive Examination (NDE) Training and Qualifications: Implications of Research on Human Learning and Memory, Instruction and Expertise.” This research showed that it can be beneficial to substitute some experience hours with laboratory practice, as while on-the-job experience helps to acclimate personnel to the field environment, structured laboratory practice may provide more experience with finding and sizing cracks and other flaws, as there are relatively few in the power plants. Based on this research, the NRC added § 50.55a(b)(2)(xviii)(D)(1) and (2), which allow for partial substitution of laboratory practice for experience hours for Level I and II UT personnel.

In parallel with the NRC's research in this area, the Electric Power Research Institute (EPRI) conducted a detailed evaluation of the number of experience hours and the structure of the laboratory practice that would be needed for personnel to obtain the needed skills to be effective examiners. The results of the EPRI work were published in a technical report titled “Technical Basis for Nondestructive Examination Experience Requirements for ASME Section XI, Appendix VII.” The NRC finds that the report provides a sufficient technical basis to support the use of reduced hours and partial substitution of laboratory hours for field experience for Personnel to obtain Levels I, II, and III UT examiner certifications. These revised requirements are described in ASME Code Case N-930. The requirements for Level I and II personnel are similar to and consistent with the NRC conditions in § 50.55a(b)(2)(xviii)(D)(1) and (2). The reduced hours for UT Level III certification are supported by the EPRI report, as well.

During a final revision to the code case, the total number of hours was revised from 600 total hours to 630 to be consistent with the ASME BPV Code, Section III UT Level II personnel experience requirements. As an oversight, this change was not reflected in the allowed laboratory practice hours in Note (d) in Table -4110-1 in the code case. The revised ASME Code Case N-930-1 has been approved by ASME Code with NRC support. Therefore, the NRC is proposing a condition to align Code Case N-930 with Code Case N-930-1 and allow the use of the code case without the error until Code Case N-930-1 is accepted into RG 1.147.

No changes were made to the OM Code Cases listed in proposed Revision 6 to RG 1.192 (with the exception of new Code Cases OMN-32 and OMN-34, discussed previously) from the versions that were listed in OM Code Cases listed in Revision 5 to RG 1.192.

The ASME Code Cases that are currently issued by the ASME but not approved for generic use by the NRC are listed in RG 1.193, “ASME Code Cases not Approved for Use.” In addition to the ASME Code Cases that the NRC has found to be technically or programmatically unacceptable, RG 1.193 includes code cases on reactor designs for high-temperature gas-cooled reactors and liquid metal reactors, reactor designs not currently licensed by the NRC, and certain requirements in Section III, Division 2, for submerged spent fuel waste casks, that are not endorsed by the NRC. RG 1.193 complements RGs 1.84, 1.147, and 1.192. It should be noted that the NRC is not proposing to adopt any of the code cases listed in RG 1.193. The NRC has included Revision 0 to OM Code Case OMN-32 in RG 1.193, because Revision 1 to Code Case OMN-32 has resolved the issues with Revision 0 of the code case.

The NRC is proposing editorial corrections to §§ 50.55a(a)(1), 50.55a(b)(2)(xliii), 50.55a(g)(4)(iv), 50.55a(g)(6)(ii)(F)( 2 )( v ), 50.55a(g)(6)(ii)(F)( 4 ), and 50.55a(g)(6)(ii)(F)(10). This proposed rule would correct a broken hyperlink in § 50.55a(a)(1), a typo to replace “Licenses shall” to “Licensees shall,” and the reference in § 50.55a(g)(4)(iv) from “(a)(1)(iv) of this section” to “(a)(1)(iii) of this section” and also correct references to the appropriate version of the ASME BPV Code Case in § 50.55a(g)(6)(ii)(F)( 2 )( v ), (g)(6)(ii)(F)( 4 ), and (g)(6)(ii)(F)( 10 ).

The references to ASME BPV Code Case N-770-5 would be replaced with ASME BPV Code Case N-770-7 in § 50.55a(g)(6)(ii)(F)( 2 )( v ), (g)(6)(ii)(F)( 4 ), and (g)(6)(ii)(F)( 10 ). ASME BPV Code Cases N-770-5 and N-770-7 versions are identical. All references in § 50.55a(g)(6)(ii)(F)( 2 )( v ), (g)(6)(ii)(F)( 4 ), and (g)(6)(ii)(F)( 10 ) to ASME BPV Code Case N-770-5 should be replaced with N-770-7, with the exception of § 50.55a(g)(6)(ii)(F)(1), which discusses the replacement to implement the requirements of ASME BPV Code Case N-770-7 instead of ASME BPV Code Case N-770-5.

Note that the content of the paragraphs and notes within the code case specific to these conditions (1100(e), 2500(a), 2500(c), 2500(d), Note 14(b) of Table 1, and Note (b) of Figure 5(a)) that are referenced in the regulations contain no differences between the N-770-5 and N-770-7 versions. Therefore, this correction would not cause any changes in what is being referenced.

The NRC is seeking advice and recommendations from the public on the proposed rule. The NRC is particularly interested in comments and supporting rationale from the public on the following:

The NRC is proposing to remove and reserve § 50.55a(a)(1)(iii)(A). This paragraph currently incorporates by reference Mandatory Appendix I of Code Case N-513-3 and was previously referenced in § 50.55a(b)(2)(xxxiv)(B). However, this paragraph has since been updated so that it no longer references the mandatory appendix. Should the NRC instead retain Mandatory Appendix I of Code Case N-513-3 in the list of documents approved for incorporation by reference? Please provide the basis for your response.

The following paragraphs describe the specific changes to § 50.55a proposed by this rulemaking.

This proposed rule would revise paragraph (a)(1) to correct the broken hyperlink to https://www.asme.org/codes-standards.

This proposed rule would revise paragraphs (a)(1)(i)(E)(20) and (21) and add new paragraph (a)(1)(i)(E)(22) to include the 2023 Edition.

This proposed rule would revise paragraphs (a)(1)(ii)(C)(56) and (57) and add new paragraph (a)(1)(ii)(C)(58) to include the 2023 Edition.

This proposed rule would remove and reserve paragraph (a)(1)(iii)(A). Mandatory Appendix I to ASME BPV Code Case N-513-3 is no longer referenced in this section.

This proposed rule would revise paragraphs (a)(1)(v)(B)(5) and (6) and add new paragraphs (a)(1)(v)(B)(7), (8), and (9) to include the 2017, 2019, and 2022 editions of NQA-1.

This proposed rule would revise the reference to “NRC Regulatory Guide 1.84, Revision 40,” by removing “Revision 40” and adding in its place “Revision 41” and changing the month and year for the document's revision date.

This proposed rule would revise the reference to “NRC Regulatory Guide 1.147, Revision 21,” by removing “Revision 21” and adding in its place “Revision 22” and changing the month and year for the document's revision date.

This proposed rule would revise the reference to “NRC Regulatory Guide 1.192, Revision 5,” by removing “Revision 5” and adding in its place “Revision 6” and changing the month and year for the document's revision date.

This proposed rule would revise the reference to “NRC Regulatory Guide 1.147, Revision 22,” by removing “Revision 21” and adding in its place “Revision 22.”

This proposed rule would revise paragraph (b)(1)(xiv) to update the applicability of this paragraph through the latest edition incorporated by reference in paragraph (a)(1)(i) of this section.

This proposed rule would add new paragraph (b)(1)(xv) to require that protection from deterioration of radiographic film shall include the provisions specified in NCA-4134.17(c) of the 2023 Edition of ASME Code, Section III, and the copy must be retained as a record in accordance with Table NCA-4134.17-1 or NCA-4134.17-2, as applicable, of the 2023 Edition of Section III. The two provisions would be added in new paragraphs (b)(1)(xv)(A) and (B).

This proposed rule would revise paragraph (b)(2)(xii) to update the applicability of this paragraph through the 2021 Edition.

This proposed rule would remove and reserve the provision in paragraph (b)(2)(xviii)(A) because this provision is no longer necessary. In addition, this proposed rule would revise paragraph (b)(2)(xviii)(D) to clarify that the alternatives listed in paragraphs (b)(2)(xviii)(D)(1) and (2) are applicable to editions and addenda later than the 2010 Edition.

This proposed rule would revise the title of paragraph (b)(2)(xxv) from “Section XV Condition” to “Section XI Condition.” This is an editorial correction.

This proposed rule would revise paragraph (b)(2)(xxviii) to add paragraphs (A) and (B). Paragraph (A) would be the existing condition applicable to the 2021 Edition and earlier. Paragraph (B) would be the existing condition applicable to the 2023 Edition and replacing reference to A-4300(b)(1) with reference to Y-3100(c).

This proposed rule would revise the current paragraph (b)(2)(xxxi) to reformat the current condition to two separate provisions, designated as new paragraphs (b)(2)(xxxi)(A) and (B). In addition, this proposed rule would add four additional provisions, designated as new paragraphs (b)(2)(xxxi)(C), (D), (E), and (F). The new provisions would maintain current NRC position on the use of Nonmandatory Appendix W concerning prohibiting use of mechanical clamps on piping for Class 1, piping that forms the containment boundary, piping larger than NPS 2 (DN 50) when nominal operating temperature or pressure exceeds 200 °F (95°C) or 275 psig (1,900 kPa), and piping larger than NPS 6 (DN 150).

This proposed rule would revise paragraph (b)(2)(xxxiv)(B) to update the applicability of this paragraph through the 2023 Edition.

This proposed rule would revise paragraph (b)(2)(xliv) to extend its applicability to the 2023 Edition, correct errors, and add paragraph (D). Paragraph (A) would be revised to “Subarticle Y-2200” instead of “Article Y-2200.” Paragraph (B) would be revised to “Subarticle Y-2400” instead of “Subarticle Y-2440.” Paragraph (C) would be revised to “Subarticle Y-3200” instead of “Article Y-3200.” New paragraph (D) would be added to prohibit the use of Nonmandatory Appendix Y, Paragraph Y-4322.

This proposed rule would revise paragraph 50.55a((b)(2)(xliii) to correct a typo, revising “Licenses shall” to “Licensees shall.”

This proposed rule would revise paragraph (b)(2)(xlv) to extend its applicability to the latest edition incorporated by reference in paragraph (a)(1)(ii) of this section.

This proposed rule would revise paragraph (b)(2)(xlvi) to extend its applicability to the latest edition incorporated by reference in paragraph (a)(1)(ii) of this section.

This proposed rule would revise paragraph (b)(2)(xlviii) to extend its applicability to the latest edition incorporated by reference in paragraph (a)(1)(ii) of this section.

This proposed rule would add new paragraph (b)(2)(li) to prohibit the use of IWA-4540(d)(7) for the 2023 Edition.

This proposed rule would add new paragraph (b)(2)(lii) to require preservice and inservice examination of nozzles fabricated from weld buildups, to require use of ultrasonic procedures and personnel compliant with Mandatory Appendix VIII, and to require the flaw acceptance criteria of IWB-3514 for Examination Category B-F welds.

This proposed rule would add new paragraph (b)(2)(liii) to require that reasonable protection from deterioration of radiographic film specified in IWA-6310(b) shall include the provisions in IWA-6320 and the reproduction must be retained as a lifetime record in accordance with IWA-6330, IWA-6340, and IWA-6350.

The NRC proposes to revise § 50.55a(g)(4)(iv) correct the reference from “(a)(1)(iv) of this section” to “(a)(1)(iii) of this section”.

This proposed rule would revise paragraph (g)(6)(ii)(D)(9) to extend the applicability of this paragraph to include the latest edition incorporated by reference in paragraph (a)(1)(ii) of this section of Supplement 15, Section XI, Division 1, Mandatory Appendix VIII.

This proposed rule would revise paragraph (g)(6)(ii)(F)(2)(iv) to include Inspection Item B-3.

This proposed rule would revise paragraph (g)(6)(ii)(F)( 2 )( v ) to correct the reference from ASME BPV Code Case N-770-5 to ASME BPV Code Case N-770-7.

This proposed rule would revise paragraph (g)(6)(ii)(F)( 4 ) to correct the reference from ASME BPV Code Case N-770-5 to ASME BPV Code Case N-770-7.

This proposed rule would revise paragraph (g)(6)(ii)(F)( 10 ); to correct the reference from ASME BPV Code Case N-770-5 to ASME BPV Code Case N-770-7.

This proposed rule would revise paragraph (g)(6)(ii)(F)(13) to include Inspection Item B-3.

In December 2010, the NRC issued NUREG-1801, Revision 2, “Generic Aging Lessons Learned (GALL) Report” (ML103490041), for applicants to use in preparing license renewal applications. The GALL Report provides aging management programs (AMPs) that the NRC has concluded are sufficient for aging management in accordance with the license renewal rule, as required in § 54.21(a)(3). In addition, NUREG-1800, Revision 2, “Standard Review Plan for Review of License Renewal Applications for Nuclear Power Plants” (ML103490036), was issued in December 2010, to ensure the quality and uniformity of NRC reviews of license renewal applications and to present a well-defined basis on which the NRC evaluates the applicant's AMPs and activities. In 2011, the NRC also issued NUREG-1950, “Disposition of Public Comments and Technical Bases for Changes in the License Renewal Guidance Documents NUREG-1801 and NUREG-1800” (ML11116A062), which describes the technical bases for the changes in Revision 2 of the GALL Report and Revision 2 of the standard review plan (SRP) for review of license renewal applications.

Revision 2 of the GALL Report, in Sections XI.M1, XI.S1, XI.S2, XI.M3, XI.M5, XI.M6, XI.M11B, and XI.S3, describes the evaluation and technical bases for determining the sufficiency of ASME BPV Code Subsections IWB, IWC, IWD, IWE, IWF, or IWL for managing aging during the period of extended operation ( i.e., up to 60 years of operation). In addition, many other AMPs in the GALL Report rely, in part but to a lesser degree, on the requirements specified in the ASME BPV Code, Section XI. Revision 2 of the GALL Report also states that the 1995 Edition through the 2004 Edition of the ASME BPV Code, Section XI, Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as modified and limited by § 50.55a, were found to be acceptable editions and addenda for complying with the requirements of § 54.21(a)(3), unless specifically noted in certain sections of the GALL Report. The GALL Report further states that future Federal Register documents that amend § 50.55a will discuss the acceptability of editions and addenda more recent than the 2004 Edition for their applicability to license renewal. In a final rule issued on June 21, 2011 (76 FR 36232), subsequent to Revision 2 of the GALL Report, the NRC also found that the 2004 Edition with the 2005 Addenda through the 2007 Edition with the 2008 Addenda of Section XI of the ASME BPV Code, Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as subject to the conditions in § 50.55a, are acceptable for the AMPs in the GALL Report and the conclusions of the GALL Report remain valid with the augmentations specifically noted in the GALL Report. In a final rule issued on July 18, 2017 (82 FR 32934), the NRC further found that the 2009 Addenda through the 2017 Edition of Section XI of the ASME BPV Code, Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as subject to the conditions in § 50.55a, are acceptable for the AMPs in the GALL Report. In a final rule issued on May 4, 2020 (85 FR 26540), the NRC further found that Subsections IWB, IWC, IWD, IWE, IWF, or IWL of Section XI of the 2015 Edition and the 2017 Edition of the ASME BPV Code, as subject to the conditions in § 50.55a, are acceptable for the AMPs in the GALL Report. In a final rule issued on October 27, 2022 (87 FR 65128), the NRC further found that Subsections IWB, IWC, IWD, IWE, IWF, or IWL of Section XI of the 2019 Edition of the ASME BPV Code, as subject to the conditions in § 50.55a, are acceptable for the AMPs in the GALL Report. In a final rule issued on August 30, 2024 (89 FR 70449), the NRC found that Subsections IWB, IWC, IWD, IWE, IWF, or IWL of Section XI of the 2021 Edition of the ASME BPV Code, as subject to the conditions in § 50.55a, are acceptable for the AMPs in the GALL Report.

In July 2025, the NRC issued NUREG-2191, Revision 1, “Generic Aging Lessons Learned for Subsequent License Renewal (GALL-SLR) Report” (ML25113A021 and ML25113A022), for applicants to use in preparing applications for subsequent license renewal. The GALL-SLR Report provides AMPs that are sufficient for aging management for the subsequent period of extended operation ( i.e., up to 80 years of operation), as required in § 54.21(a)(3). The NRC also issued NUREG-2192, Revision 1, “Standard Review Plan for Review of Subsequent License Renewal Applications for Nuclear Power Plants” (SRP-SLR), in July 2025 (ML25113A023). In a similar manner as the GALL Report does, the GALL-SLR Report, in Sections XI.M1, XI.S1, XI.S2, XI.M3, XI.11B, and XI.S3, describes the evaluation and technical bases for determining the sufficiency of ASME BPV Code Subsections IWB, IWC, IWD, IWE, IWF, or IWL for managing aging during the subsequent period of extended operation. Many other AMPs in the GALL-SLR Report rely, in part but to a lesser degree, on the requirements specified in the ASME BPV Code, Section XI. The GALL-SLR Report also indicates that the 1995 Edition through the 2023 Edition (if and when published) of the ASME BPV Code, Section XI, Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as subject to the conditions in § 50.55a, are acceptable for complying with the requirements of § 54.21(a)(3), unless specifically noted in certain sections of the GALL-SLR Report.

The NRC evaluated whether those AMPs in the GALL Report and GALL-SLR Report that rely upon Subsections IWB, IWC, IWD, IWE, IWF, or IWL of Section XI in the editions and addenda of the ASME BPV Code incorporated by reference into § 50.55a, in general continue to be acceptable if the AMP relies upon these Subsections in the 2023 Edition. The NRC finds that the 2023 Edition of Section XI of the ASME BPV Code, Subsections IWB, IWC, IWD, IWE, IWF, or IWL, as subject to the conditions of this proposed rule, are acceptable for the AMPs in the GALL Report and GALL-SLR Report with the exception of augmentation, as specifically noted in those reports, and the NRC finds that the conclusions of the GALL Report and GALL-SLR Report remain valid. Accordingly, an applicant for license renewal (including subsequent license renewal) may use, in its plant-specific license renewal application, Subsections IWB, IWC, IWD, IWE, IWF, or IWL of Section XI of the 2023 Edition of the ASME BPV Code, as subject to the conditions in this proposed rule, without additional justification. Similarly, a licensee approved for license renewal that relied on the AMPs may use Subsections IWB, IWC, IWD, IWE, IWF, or IWL of Section XI of the 2023 Edition of the ASME BPV Code. However, applicants must assess and follow applicable NRC requirements with regard to licensing basis changes and evaluate the possible impact on the elements of existing AMPs.

Some of the AMPs in the GALL Report and GALL-SLR Report recommend augmentation of certain Code requirements in order to ensure adequate aging management for license renewal. The technical and regulatory aspects of the AMPs for which augmentations are recommended also apply if the 2023 Edition of Section XI of the ASME BPV Code is used to meet the requirements of § 54.21(a)(3). The NRC evaluated the changes in the 2023 Edition of Section XI of the ASME BPV Code to determine if the augmentations described in the GALL Report and GALL-SLR Report remain necessary. The NRC's evaluation has concluded that the augmentations described in the GALL and GALL-SLR Reports are necessary to ensure adequate aging management.

For example, GALL-SLR Report AMP XI.S3, “ASME Section XI, Subsection IWF,” recommends that volumetric examination consistent with that of the ASME BPV Code, Section XI, Table IWB-2500-1, Examination Category B-G-1 should be performed to detect cracking for high strength structural bolting (actual measured yield strength greater than or equal to 150 kilopound per square inch (ksi)) (1,034 megapascals (MPA)) in sizes greater than 1 inch nominal diameter. The GALL-SLR Report also indicates that this volumetric examination may be waived with adequate plant-specific justification. This guidance for aging management in the GALL-SLR Report is the augmentation of the visual examination specified in Subsection IWF of the 2023 Edition of the ASME BPV Code, Section XI.

A license renewal applicant may either augment its AMPs as described in the GALL Report and GALL-SLR Report (for operation up to 60 and 80 years respectively) or propose alternatives for the NRC to review as part of the applicant's plant-specific justification for its AMPs.

As required by the Regulatory Flexibility Act of 1980, 5 U.S.C. 605(b), the Commission certifies that this rule, if adopted, will not have a significant economic impact on a substantial number of small entities. This proposed rule affects only the licensing and operation of nuclear power plants. The companies that own these plants do not fall within the scope of the definition of “small entities” set forth in the Regulatory Flexibility Act or the size standards established by the NRC (10 CFR 2.810).

The NRC has prepared a draft regulatory analysis on this proposed regulation. The analysis examines the costs and benefits of the alternatives considered by the NRC. The NRC requests public comment on the draft regulatory analysis. The draft regulatory analysis is available as indicated in the “Availability of Documents” section of this document. Comments on the draft regulatory analysis may be submitted to the NRC as indicated under the ADDRESSES caption of this document.

The NRC's Backfit Rule in § 50.109 states that the NRC shall require the backfitting of a facility only when it finds the action to be justified under specific standards stated in the rule. Section 50.109(a)(1) defines backfitting as the modification of or addition to systems, structures, components, or design of a facility; the design approval or manufacturing license for a facility; or the procedures or organization required to design, construct, or operate a facility. Any of these modifications or additions may result from a new or amended provision in the NRC's rules or the imposition of a regulatory position interpreting the NRC's rules that is either new or different from a previously applicable NRC position after issuance of the construction permit or the operating license or the design approval.

Section 50.55a requires nuclear power plant licensees to:

• Construct ASME BPV Code Class 1, 2, and 3 components in accordance with the rules provided in Section III, Division 1, of the ASME BPV Code (“Section III”).

• Inspect, examine, and repair or replace Class 1, 2, 3, Class MC, and Class CC components in accordance with the rules provided in Section XI, Division 1, of the ASME BPV Code (“Section XI”).

• Test Class 1, 2, and 3 pumps and valves in accordance with the rules provided in the ASME OM Code.

• Inspect, examine, repair or replace, and test Class 1, 2, and 3 dynamic restraints (snubbers) in accordance with the rules provided in either the ASME OM Code or Section XI, depending on the code edition.

This rulemaking proposes to incorporate by reference the 2023 Edition of the ASME BPV Code, Section III, Division 1, and ASME BPV Code, Section XI, Division 1.

The ASME BPV and OM Codes are national consensus standards developed by participants with broad and varied interests, in which all interested parties (including the NRC and utilities) participate. A consensus process involving a wide range of stakeholders is consistent with the NTTAA, inasmuch as the NRC has determined that there are sound regulatory reasons for establishing regulatory requirements for design, maintenance, ISI, and IST by rulemaking. The process also facilitates early stakeholder consideration of backfitting issues.

Incorporation by reference of more recent editions and addenda of Section III of the ASME BPV Code does not affect a plant that has received a construction permit or an operating license or a design that has been approved. This is because the edition and addenda to be used in constructing a plant are, under § 50.55a, determined based on the date of the construction permit or combined license, and are not changed thereafter, except voluntarily by the licensee. The incorporation by reference of more recent editions and addenda of Section III ordinarily applies only to applicants after the effective date of the final rule incorporating these new editions and addenda. Therefore, incorporation by reference of a more recent edition and addenda of Section III does not constitute “backfitting” as defined in § 50.109(a)(1).

Incorporation by reference of more recent editions and addenda of Section XI of the ASME BPV Code affects the ISI program of operating reactors. However, the Backfit Rule generally does not apply to incorporation by reference of later editions of the ASME BPV Code (Section XI). As previously mentioned, the NRC's longstanding regulatory practice has been to incorporate later versions of the ASME Codes into § 50.55a. Under § 50.55a, licensees must periodically update their ISI and program to the latest edition of Section XI of the ASME BPV Code incorporated by reference into § 50.55a 18 months before the start of a new code of record interval. Therefore, when the NRC approves and requires the use of a later version of the Code for ISI, it is implementing this longstanding regulatory practice and requirement.

Other circumstances where the NRC does not apply the Backfit Rule to the approval and requirement to use later code editions and addenda are as follows:

1. When the NRC takes exception to a later ASME BPV Code or OM Code provision but merely retains the current existing requirement, prohibits the use of the later code provision, limits the use of the later code provision, or supplements the provisions in a later code, the Backfit Rule does not apply because the NRC is not imposing new requirements. However, the NRC explains any such exceptions to the code in the preamble to and regulatory analysis for the rule.

2. When an NRC exception relaxes an existing ASME BPV Code or OM Code provision but does not prohibit a licensee from using the existing code provision, the Backfit Rule does not apply because the NRC is not imposing new requirements.

3. Modifications and limitations imposed during previous routine updates of § 50.55a have established a precedent for determining which modifications or limitations are backfits, or require a backfit analysis ( e.g., final rule dated September 10, 2008 (73 FR 52730), and a correction dated October 2, 2008 (73 FR 57235)). The application of the backfit requirements to modifications and limitations in the current rule are consistent with the application of backfit requirements to modifications and limitations in previous rules.

The incorporation by reference and adoption of a requirement mandating the use of a later ASME BPV Code or OM Code may constitute backfitting in some circumstances. In these cases, the NRC would perform a backfit analysis or prepare documented evaluation in accordance with § 50.109. These include the following:

1. When the NRC endorses a later provision of the ASME BPV Code or OM Code that takes a substantially different direction from the existing requirements, the action is treated as a backfit ( e.g., 61 FR 41303; August 8, 1996).

2. When the NRC requires implementation of a later ASME BPV Code or OM Code provision on an expedited basis, the action is treated as a backfit. This applies when implementation is required sooner than it would be required if the NRC simply endorsed the Code without any expedited language ( e.g., 64 FR 51370; September 22, 1999).

3. When the NRC takes an exception to an ASME BPV Code or OM Code provision and imposes a requirement that is substantially different from the existing requirement as well as substantially different from the later Code ( e.g., 67 FR 60520; September 26, 2002).

This section discusses the backfitting considerations for all the proposed changes to § 50.55a that go beyond the minimum changes necessary and are required to adopt the new ASME Code edition into § 50.55a.

1. Revise § 50.55a(b)(1)(xiv) to extend the applicability of the conditions through the latest edition of the ASME BPV Code, Section III incorporated by reference in paragraph (a)(1)(i). The NRC is proposing to revise this condition to apply to the latest edition incorporated by reference, which is not a change to NRC position and, therefore, is not a backfit.

2. Add § 50.55a(b)(1)(xv) to include provisions to require that protection from deterioration of radiographic film specified in Note (3) of Table NCA-4134.17-1 and Note (1) of Table NCA-4134.17-2 of the 2023 Edition of the ASME BPV Code, Section III shall include the provisions specified in NCA-4134.17(c), and the reproduction must be retained as a lifetime or nonpermanent record in accordance with Table NCA-4134.17-1 or NCA-4134.17-2, as applicable, of the 2023 Edition. The proposed conditions on Note (3) of Table NCA-4134.17-1 and Note (1) of Table NCA-4134.17-2 of the 2023 Edition specify that existing provisions in NCA-4134.17(c) allow digitization of radiographic film before the original film's deterioration to protect and preserve the record as required. This is not a new or changed NRC position. Therefore, the addition of this proposed condition to maintain the radiographic film or digitized radiographic film as a permanent record is not a backfit.

1. Remove and reserve § 50.55a(a)(1)(iii)(A) to delete the incorporation by reference of ASME BPV Code Case N-513-3, Mandatory Appendix I. The mandatory appendix was previously referenced in § 50.55a(b)(2)(xxxiv), but that reference was removed from this condition in a previous rulemaking. The NRC is proposing to remove this incorporation by reference, which is not a change to NRC position and, therefore, is not a backfit.

2. Revise § 50.55a(b)(2)(xii) to limit the applicability of the condition to the 2001 Edition through the 2021 Edition of ASME BPV Code, Section XI. The 2023 Edition added provisions that satisfied the conditions in this paragraph. The NRC is proposing to not apply this condition to the 2023 Edition incorporated by reference, which is not a change to NRC position and, therefore, is not a backfit.

3. Revise § 50.55a(b)(2)(xviii) to remove and reserve a provision and clarify a provision.

a. The current provision in § 50.55a(b)(2)(xviii)(A) is being removed as the NRC believes that the NDE recertification rate is acceptable. Removing this condition allows licensees to voluntarily apply the less stringent requirements for recertification of Level I and II NDE personnel to 5-year intervals as stated in the ASME BPV Code, Section XI. Therefore, this is not a backfit.

b. The current provision in § 50.55a(b)(2)(xviii)(D) is being revised to clarify that the alternatives listed in paragraphs (b)(2)(xviii)(D)(1) and (2) are applicable to editions and addenda later than the 2010 Edition. This is not a change in NRC position and, therefore, is not a backfit.

4. Revise § 50.55a(b)(2)(xxv) to correct an error in the title. The current title of this section incorrectly states, “Section XV Condition,” and the NRC proposes to correct the title to state, “Section XI Condition.” This is an editorial correction and, therefore, is not a backfit.

5. Revise § 50.55a(b)(2)(xxviii) to clarify that the condition applies to A-4300(b)(1) for the 2021 Edition of the ASME BPV Code, Section XI, and earlier, and applies to Y-3100(c) in the 2023 Edition. In the 2023 Edition, ASME moved the fatigue crack growth law for ferritic steels in air from A-4300 to Y-3100. This is not a change in NRC position and, therefore, is not a backfit.

6. Revise § 50.55a(b)(2)(xxxi) to reformat the existing condition into two separate provisions and add four new provisions.

a. The current condition continues to apply and is being reformatted into two separate provisions. This is not a change to NRC position and, therefore, is not a backfit.

b. Appendix W of the 2023 Edition of the ASME BPV Code, Section XI, was revised to remove the prohibition on the use of mechanical clamps for several types of piping. The NRC continues to prohibit the use of mechanical clamps in these four specific types of piping. This is not a new or changed position and, therefore, is not a backfit.

7. Revise § 50.55a(b)(2)(xxxiv) to extend the applicability of the condition to the 2023 Edition of the ASME BPV Code, Section XI. The NRC is proposing to revise this condition to apply to the 2023 Edition incorporated by reference, which is not a change to NRC position and, therefore, is not a backfit.

8. Revise § 50.55a(b)(2)(xliv) to correct errors, extend its applicability to the 2023 Edition of the ASME BPV Code, Section XI, and add a provision.

a. Subarticle Y-2400 and Articles Y-2200 and Y-3200 are all incorrect references. The NRC is proposing to fix these errors. This is an editorial correction, not a change in position, and, therefore, not a backfit.

b. The NRC is proposing to revise this condition to extend to the 2023 Edition, which is not a change in position and, therefore, is not a backfit.

c. The NRC is proposing to prohibit the use of paragraph Y-4322. The NRC's position is that the relevant code case should govern whenever there are overlapping requirements between the ASME BPV Code and a code case. The crack growth laws in paragraph Y-4322 are duplicated in Code Case N-909. The prohibiting of the use of this paragraph does not modify the requirements with regards to crack growth laws and, therefore, is not a backfit.

9. Revise § 50.55a(b)(2)(xlv) to extend the applicability of the condition through the latest edition of the ASME BPV Code, Section XI. The NRC is proposing to revise this condition to apply to the latest edition incorporated by reference, which is not a change to NRC position and, therefore, is not a backfit.

10. Revise § 50.55a(b)(2)(xlvi) to extend the applicability of the condition through the latest edition of the ASME BPV Code, Section XI. The NRC is proposing to revise this condition to apply to the latest edition incorporated by reference, which is not a change to NRC position and, therefore, is not a backfit.

11. Revise § 50.55a(b)(2)(xlviii) to extend the applicability of the condition through the latest edition of the ASME BPV Code, Section XI. The NRC is proposing to revise this condition to apply to the latest edition incorporated by reference, which is not a change to NRC position and, therefore, is not a backfit.

12. Add § 50.55a(b)(2)(li) to prohibit the use of IWA-4540(d)(7) in the 2023 Edition of the ASME BPV Code, Section XI, for exempting pressure testing of Class 2 and 3 welds that have a surface or volumetric examination performed. This is a new condition that retains the NRC's current position to perform pressure testing of most welds regardless of the non-destructive examination performed. The proposed condition on IWA-4540(d)(7) does not constitute a new or changed NRC position. Therefore, the addition of this proposed condition is not a backfit.

13. Add § 50.55a(b)(2)(lii) to condition Figure IWB-2500-7(d) of the 2023 Edition of the ASME BPV Code, Section XI, to require preservice and inservice volumetric examination of nozzles fabricated from weld buildups. This new condition retains a requirement from previous code editions; it does not constitute a new or changed NRC position. Therefore, the addition of this proposed condition is not a backfit.

14. Add § 50.55a(b)(2)(liii) to include provisions to require that protection from deterioration of radiographic film specified in IWA-6310(b) of the 2023 Edition of ASME BPV Code, Section XI, shall include the provisions specified in IWA-6320, and the reproduction must be retained as a lifetime record in accordance with IWA-6330, IWA-6340, and IWA-6350 of the ASME BPV Code, Section XI. The proposed condition on IWA-6310(b) of the 2023 Edition specifies that existing provisions in IWA-6320 allow digitization of radiographic film before the original film's deterioration to protect and preserve the lifetime record as required. This is not a new or changed NRC position. Therefore, the addition of this proposed condition to maintain the radiographic film or digitized radiographic film as a permanent record is not a backfit.

15. Revise § 50.55a(g)(6)(ii)(D)(9) to allow for qualification of volumetric evaluation in accordance with Section XI, Division 1, Mandatory Appendix VIII, Supplement 15, in the 2021 Edition through the latest edition of the ASME BPV Code, Section XI. The NRC is proposing to allow licensees the further option to utilize the 2023 Edition of Supplement 15 for the volumetric qualification requirements of Code Case N-729-6, which is a voluntary alternative and, therefore, is not a backfit.

16. Revise § 50.55a(g)(6)(ii)(F)(2)(iv) to include inspection item B-3 in the list of categorization options for identification of cold leg temperature welds. Inspection item B-3 was previously part of inspection item B-1. The NRC is proposing to revise this condition to include inspection item B-3, which maintains the same requirements and only clarifies the expansion of categorization options for licensees and, therefore, is not a backfit.

17. Revise § 50.55a(g)(6)(ii)(F)(13) to include inspection item B-3 in the list of encoded volumetric exams. Inspection item B-3 was previously part of inspection item B-1. The NRC is proposing to revise this condition to include inspection item B-3, which maintains the same requirements and only clarifies the expansion of categorization options for licensees and, therefore, is not a backfit.

The NRC finds that incorporation by reference into § 50.55a of the 2023 Edition of the ASME BPV Code, subject to the identified conditions, does not constitute backfitting or represent an inconsistency with any issue finality provisions in 10 CFR part 52.

The provisions in this proposed rule would allow licensees and applicants to voluntarily apply NRC-approved code cases, sometimes with NRC-specified conditions. The approved code cases are listed in three RGs that are proposed to be incorporated by reference into § 50.55a. An applicant's or a licensee's voluntary application of an approved code case does not constitute backfitting, because there is no imposition of a new requirement or new position.

Similarly, voluntary application of an approved code case by a 10 CFR part 52 applicant or licensee does not represent NRC imposition of a requirement or action and therefore is not inconsistent with any issue finality provision in 10 CFR part 52. The NRC is not proposing to revise any conditions on previously approved code cases, and approval of new code cases with conditions on their voluntary use does not represent an imposition of a new requirement and is therefore not a backfit. For these reasons, the NRC finds that this proposed rule does not involve any provisions requiring the preparation of a backfit analysis or documentation demonstrating that one or more of the issue finality criteria in 10 CFR part 52 are met.

The NRC finds that the proposed incorporation by reference into § 50.55a of the three RGs containing the latest NRC-approved code cases does not constitute backfitting or represent an inconsistency with any issue finality provisions in 10 CFR part 52.

The Plain Writing Act of 2010 (Pub. L. 111-274) requires Federal agencies to write documents in a clear, concise, and well-organized manner. The NRC has written this document to be consistent with the Plain Writing Act as well as the Presidential Memorandum, “Plain Language in Government Writing,” published June 10, 1998 (63 FR 31885). The NRC requests comment on this document with respect to the clarity and effectiveness of the language used.

The NRC has determined under the National Environmental Policy Act of 1969, as amended, and the Commission's regulations in subpart A of 10 CFR part 51, that this rule, if adopted, would not be a major Federal action significantly affecting the quality of the human environment and, therefore, an environmental impact statement is not required.

The determination of this environmental assessment is that there will be no significant effect on the quality of the human environment from this action. Public stakeholders should note, however, that comments on any aspect of this environmental assessment may be submitted to the NRC as indicated under the ADDRESSES caption.

This proposed rule is in accordance with the NRC's policy to incorporate by reference in § 50.55a new editions of the ASME BPV and OM Codes to provide updated rules for construction and inspecting components and testing pumps, valves, and dynamic restraints (snubbers) in light-water nuclear power plants. The ASME Codes are national voluntary consensus standards and are required by the NTTAA to be used by Government agencies unless the use of such a standard is inconsistent with applicable law or otherwise impractical. The proposed rule does not significantly increase the probability or consequences of accidents, no changes are being made in the types of effluents that may be released off-site, and there is no significant increase in public radiation exposure. This proposed rule does not involve non-radiological plant effluents and has no other environmental impact. Therefore, no significant environmental impacts are associated with this action.

NRC-approved code cases provide an equivalent level of safety as the ASME codes. Therefore, this proposed action does not result in increases in the probability or consequences of accidents. There also are no significant, non-radiological impacts associated with this action because no changes would be made affecting non-radiological plant effluents and because no changes would be made in activities that would adversely affect the environment. The determination of this environmental assessment is that there would be no significant impact from this action.

This proposed rule amends a collection of information subject to the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq. ). The proposed rule would reduce the burden for the existing information collection. This proposed rule has been submitted to the Office of Management and Budget (OMB) for review and approval of the paperwork requirements.

Type of submission: Revision.

The title of the information collection: Codes and Standards.

The form number if applicable: Not applicable.

How often the collection is required or requested: On occasion.

Who will be required or asked to respond: Operating power reactor licensees and applicants who choose to implement Code Case N-752-2.

An estimate of the number of annual responses: 1.

The estimated number of annual respondents: 3.33.

An estimate of the total number of hours needed annually to comply with the information collection requirement or request: One-time recordkeeping burden of 1,800 hours, recurring annual recordkeeping burden reduction of 5,390 hours.

Abstract: This proposed rule, in part, approves the implementation of Code Case N-752-2, with conditions as specified in RG 1.147. In order to implement the code case, licensees and applicants would be required to evaluate the safety-significant functions of their SSCs, and would need to follow requirements for on-going evaluations to ensure safety standards are maintained and that records of categorization decisions be kept.

The NRC is seeking public comment on the potential impact of the information collection(s) contained in this proposed rule and on the following issues:

1. Is the proposed information collection necessary for the proper performance of the functions of the NRC, including whether the information will have practical utility? Please explain your response.

2. Is the estimate of the burden of the proposed information collection accurate? Please explain your response.

3. Is there a way to enhance the quality, utility, and clarity of the information to be collected? Please explain your response.

4. How can the burden of the proposed information collection on respondents be minimized, including the use of automated collection techniques or other forms of information technology?

A copy of the OMB clearance package is available in ADAMS under Accession No. ML25225A001 or may be viewed free of charge by contacting the NRC's Public Document Room reference staff at 1-800-397-4209, at 301-415-4737, or by email to PDR.Resource@nrc.gov. You may obtain information and comment on submissions related to the OMB clearance package by searching on https://www.regulations.gov under Docket ID NRC-2020-0029.

You may submit comments on any aspect of these proposed information collection(s), including suggestions for reducing the burden and on the above issues, by the following methods:

• Federal rulemaking website: Go to https://www.regulations.gov and search for Docket ID NRC-2020-0029.

• Mail comments to: FOIA, Library, and Information Collections Branch, Office of the Chief Information Officer, Mail Stop: T-6 A10M, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001 or to the OMB reviewer at OMB Office of Information and Regulatory Affairs (3150-0264), Attention: Desk Officer for the Nuclear Regulatory Commission, 725 17th Street NW, Washington, DC 20503.

Submit comments by March 30, 2026. Comments received after this date will be considered if it is practical to do so, but the NRC is able to ensure consideration only for comments received on or before this date.

The NRC may not conduct or sponsor, and a person is not required to respond to, a collection of information unless the document requesting or requiring the collection displays a currently valid OMB control number.

The following are E.O.s that are related to this proposed rule:

This action is not a significant regulatory action and therefore was not submitted to OMB for review.

The NRC has examined this proposed rule and has determined that it is consistent with the policies and directives outlined in E.O. 14154.

This action is a deregulatory action as defined by E.O. 14192. Details on the estimated costs of this proposed rule can be found in Section VIII of this document, “Regulatory Analysis.”

E.O. 14270, “Zero-Based Regulatory Budgeting to Unleash American Energy,” requires the NRC to insert a conditional sunset date into all new or amended NRC regulations provided the regulations are (1) promulgated under the Atomic Energy Act of 1954, as amended (AEA), the Energy Reorganization Act of 1974, as amended, or the Nuclear Waste Policy Act of 1982, as amended; (2) not statutorily required; and (3) not part of the NRC's permitting regime. The NRC determined that the regulatory changes proposed in this rule are necessary for reasonable assurance of adequate protection of public health and safety and part of the NRC's regulatory permitting scheme authorized by the AEA. Therefore, the NRC views this rulemaking to be outside the scope of E.O. 14270 and did not insert conditional sunset dates for the regulatory changes in this proposed rule.

The National Technology Transfer and Advancement Act of 1995, Public Law 104-113, requires that Federal agencies use technical standards that are developed or adopted by voluntary consensus standards bodies unless using such a standard is inconsistent with applicable law or is otherwise impractical. In this proposed rule, the NRC is continuing to use the ASME BPV Code by incorporating by reference the 2023 Edition of the BPV Code. In addition, the NRC is continuing to use the ASME BPV and OM Code Cases, which are ASME-approved voluntary alternatives to compliance with various provisions of the ASME BPV and OM Codes. The NRC's approval of the ASME Code Cases is accomplished by amending the NRC's regulations to incorporate by reference the latest revisions of the following, which are the subject of this rulemaking, into § 50.55a: RG 1.84, Revision 41; RG 1.147, Revision 22; and RG 1.192, Revision 6. The RGs list the ASME Code Cases that the NRC has approved for use. The ASME Code Cases are voluntary consensus standards as described in the National Technology Transfer and Advancement Act of 1995 and OMB Circular A-119. The ASME Code editions and code cases constitute voluntary consensus standards, in which all interested parties (including the NRC and licensees of nuclear power plants) participate. The NRC invites comment on the applicability and use of other standards.

The NRC proposes to incorporate by reference the 2023 Edition of the ASME BPV Code for nuclear power plants. As described in the “Background” and “Discussion” sections of this document, this material contains standards for the inspection of nuclear power plant components.

The NRC also proposes to incorporate by reference three NRC RGs that list new and revised ASME Code cases that the NRC has approved as voluntary alternatives to certain provisions of NRC-required editions and addenda of the ASME BPV Code and the ASME OM Code. The draft regulatory guides, DG-1446, DG-1447, and DG-1448, will correspond to final RG 1.84, Revision 41; RG 1.147, Revision 22; and RG 1.192, Revision 6, respectively.

• RG 1.84, “Design, Fabrication, and Materials Code Case Acceptability, ASME Section III,” Revision 41 (DG-1446), would allow nuclear power plant licensees and applicants for construction permits, operating licenses, combined licenses, standard design certifications, standard design approvals, and manufacturing licenses to use the code cases listed in this revised RG as voluntary alternatives to ASME engineering standards for the construction of nuclear power plant components. DG-1446 updates the discussion language of the document and does not list any new code cases.

• RG 1.147, “Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1,” Revision 22 (DG-1447), would allow nuclear power plant licensees and applicants for construction permits, operating licenses, combined licenses, standard design certifications, standard design approvals, and manufacturing licenses to use the code cases newly listed in this revised RG as voluntary alternatives to ASME engineering standards for the inservice inspection of nuclear power plant components.

• RG 1.192, “Operation and Maintenance [OM] Code Case Acceptability, ASME OM Code,” Revision 6 (DG-1448), would allow nuclear power plant licensees and applicants for construction permits, operating licenses, combined licenses, standard design certifications, standard design approvals, and manufacturing licenses to use the code cases newly listed in this revised RG as voluntary alternatives to ASME engineering standards for the inservice examination and testing of nuclear power plant components.

The NRC is required by law to obtain approval for incorporation by reference from the Office of the Federal Register (OFR). The OFR's requirements for incorporation by reference are set forth in 1 CFR part 51. On November 7, 2014, the OFR adopted changes to its regulations governing incorporation by reference (79 FR 66267). The OFR regulations require an agency to include in a proposed rule a discussion of the ways that the materials the agency proposes to incorporate by reference are reasonably available to interested parties or how it worked to make those materials reasonably available to interested parties. The discussion in this section complies with the requirement for proposed rules as set forth in 1 CFR 51.5(a)(1).

The NRC considers “interested parties” to include all potential NRC stakeholders, not only the individuals and entities regulated or otherwise subject to the NRC's regulatory oversight. These NRC stakeholders are not a homogenous group, so the considerations for determining “reasonable availability” vary by class of interested parties. The NRC identified six classes of interested parties with regard to the material to be incorporated by reference in an NRC rule:

• Individuals and small entities regulated or otherwise subject to the NRC's regulatory oversight. This class includes applicants and potential applicants for licenses and other NRC regulatory approvals, and who are subject to the material to be incorporated by reference. In this context, “small entities” has the same meaning as set out in § 2.810.

• Large entities otherwise subject to the NRC's regulatory oversight. This class includes applicants and potential applicants for licenses and other NRC regulatory approvals, and who are subject to the material to be incorporated by reference. In this context, a “large entity” is one that does not qualify as a “small entity” under § 2.810.

• Non-governmental organizations with institutional interests in matters regulated by the NRC.

• Other Federal agencies, States, local governmental bodies (within the meaning of § 2.315(c)).

• Federally recognized and State-recognized Indian tribes.

• Members of the general public ( i.e., individual, unaffiliated members of the public who are not regulated or otherwise subject to the NRC's regulatory oversight) who need access to the materials that the NRC proposes to incorporate by reference in order to participate in the rulemaking.

The 2023 Edition of the ASME BPV Code may be viewed, by appointment, at the Technical Library, which is located at Two White Flint, 11545 Rockville Pike, Rockville, Maryland 20852. You may submit your request to the Technical Library via email at Library.Resource@nrc.gov between 8:00 a.m. and 4:00 p.m. eastern time, Monday through Friday, except Federal holidays. In addition, as described in the “Availability of Documents” section of this document, documents related to this proposed rule are available online in the NRC's ADAMS Public Documents collection at https://www.nrc.gov/reading-rm/adams.html.

Interested parties may purchase a copy of the ASME materials from ASME at Three Park Avenue, New York, NY 10016, or at the ASME website https://www.asme.org/shop/standards. The materials also are accessible through third-party subscription services such as IHS (15 Inverness Way East, Englewood, CO 80112; https://global.ihs.com ) and Thomson Reuters Techstreet (3916 Ranchero Dr., Ann Arbor, MI 48108; https://www.techstreet.com ). The purchase prices for individual documents range from $325 to $720 and the cost to purchase all documents is approximately $9,000.

For the class of interested parties constituting members of the public who wish to gain access to the materials to be incorporated by reference in order to participate in the rulemaking, the NRC recognizes that the $9,000 cost may be so high that the materials could be regarded as not reasonably available for purposes of commenting on this proposed rule, despite the NRC's actions to make the materials available at the NRC's PDR. Accordingly, the NRC requested that ASME consider enhancing public access to these materials during the public comment period. On January 21, 2026, the ASME agreed to make the materials available online in a read-only electronic access format during the public comment period (ML26023A041). Therefore, the 2023 Edition of the ASME BPV Code Edition for nuclear power plants that the NRC proposes to incorporate by reference in this rulemaking is available in read-only format at the ASME website https://go.asme.org/NRC-ASME.

The three draft RGs that the NRC proposes to incorporate by reference in this proposed rule are available without cost and can be read online or downloaded online. The draft RGs can be viewed, by appointment, at the NRC Technical Library, which is located at Two White Flint North, 11545 Rockville Pike, Rockville, Maryland 20852; telephone: 301-415-7000; email: Library.Resource@nrc.gov.

Because the three draft RGs, and eventually, the final RGs, are available in various forms at no cost, the NRC determines that the three draft RGs, DG-1446, DG-1447, and DG-1448, and final RG 1.84, Revision 41; RG 1.147, Revision 22; and RG 1.192, Revision 6, once approved by the OFR for incorporation by reference, are reasonably available to all interested parties.

The materials are available to all interested parties in multiple ways and in a manner consistent with their interest in this proposed rule. Therefore, the NRC concludes that the materials the NRC proposes to incorporate by reference in this proposed rule are reasonably available to all interested parties.

The NRC will not be issuing guidance for this rulemaking.

The documents identified in the following table are available to interested persons through one or more of the following methods, as indicated in Table IV.

The NRC proposes to incorporate by reference three NRC RGs, as set forth in Table V, that list new and revised ASME Code Cases that the NRC is proposing to approve as voluntary alternatives to certain provisions of NRC-required editions and addenda of the ASME BPV Code and the ASME OM Code.

The ASME OM Code Cases that the NRC is proposing to approve as alternatives to certain provisions of the ASME OM Code, as set forth in Table VI, are made available for read-only access at the URL listed in Table IV. The ASME BPV Code Cases that the NRC is proposing to approve as alternatives to certain provisions of the ASME BPV Code, as set forth in Table VI, are being made available by the ASME for read-only access during the public comment period on https://go.asme.org/NRC-ASME.

The ASME is making the code cases listed in Table VI available for limited, read-only access at the request of the NRC. The NRC believes that stakeholders need to be able to read these code cases in order to provide meaningful comment on the three RGs (listed in Table V) that the NRC is proposing to incorporate by reference into § 50.55a. It is the NRC's position that the listed code cases, as modified by any conditions contained in the three RGs and thus serving as alternatives to requirements in § 50.55a, would be legally-binding regulatory requirements. An applicant or licensee must comply with a listed code case and any conditions to be within the scope of the NRC's approval of the code case as a voluntary alternative for use. These requirements cannot be fully understood without knowledge of the code case to which the proposed condition applies, and to this end, the NRC has requested that the ASME provide limited, read-only access to the code cases in order to facilitate meaningful public comment.

The NRC may post materials related to this document, including public comments, on the Federal rulemaking website at https://www.regulations.gov under Docket ID NRC-2020-0029. In addition, the Federal rulemaking website allows members of the public to receive alerts when changes or additions occur in a docket folder. To subscribe: (1) navigate to the docket folder (NRC-2020-0029); (2) click the “Subscribe” button; and (3) enter an email address and click on the “Subscribe” button.

For the reasons set out in the preamble and under the authority of the Atomic Energy Act of 1954, as amended; the Energy Reorganization Act of 1974, as amended; and 5 U.S.C. 552 and 553, the NRC is proposing to amend 10 CFR part 50 as follows:

The revisions and additions read as follows:

FCA's objectives in proposing this rule are to:

• Reduce the role of permanent capital as a measure of capital adequacy by replacing references to “permanent capital” or “capital” in certain FCA regulations with references to “total capital” as defined in part 628.

• Respond to previous System comments that calculating the permanent capital ratio is burdensome by simplifying the calculation as permitted by statute.

• Respond to previous System comments that disclosure of permanent capital may be confusing to third parties by eliminating the disclosure of permanent capital from shareholder and investor reporting requirements.

• Make other clarifications, corrections, and updates to capital-related regulations.

In 1916, Congress created the System to provide permanent, affordable, and reliable sources of credit and related services to American agricultural and aquatic producers. 1 The System is a Government-sponsored enterprise (GSE). System institutions are Federal instrumentalities that operate on a cooperative basis, and FCA is their regulator. FCA and the System derive their authorities from the Farm Credit Act of 1971, as amended (1971 Act). 2

As of January 1, 2025, the System consists of three Farm Credit Banks, one agricultural credit bank, 54 agricultural credit associations, one Federal land credit association, several service corporations, and the Federal Farm Credit Banks Funding Corporation (Funding Corporation). System banks (which include both the Farm Credit Banks and the agricultural credit bank) issue System-wide consolidated debt obligations in the capital markets through the Funding Corporation, 3 which enables associations to provide short-, intermediate-, and long-term credit and related services to eligible borrowers. Eligible borrowers include farmers, ranchers, producers and harvesters of aquatic products, their cooperatives, rural utilities, exporters of agricultural commodities products, rural residents for housing, and farm-related service businesses. 4

To be able to survive in times of stress, financial institutions, including System institutions, must hold an adequate amount of high-quality capital that is permanent, stable, and immediately available to absorb losses. In 1985, Congress added a requirement in section 4.3(a) of the 1971 Act that FCA “shall cause System institutions to achieve and maintain adequate capital by establishing minimum levels of capital for such System institutions and by using such other methods as the [FCA] deems appropriate.”  5

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 modify Class E airspace to support IFR operations at Nenana Municipal Airport, Nenana, AK.

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 Northwest Mountain Regional Office of the Federal Aviation Administration, Air Traffic Organization, Western Service Center, Operations Support Group, 2200 S 216th Street, Des Moines, WA 98198.

Class E5 airspace designations are published in paragraph 6005 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 7400.11K, dated August 4, 2025, and effective September 15, 2025. These updates would be published in the next update to FAA Order JO 7400.11. FAA Order JO 7400.11K, 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.

The FAA is proposing an amendment to 14 CFR part 71 that would modify the Class E airspace extending upward from 700 feet above the surface at Nenana Municipal Airport, Nenana, AK.

The Area Navigation (RNAV) (Global Positioning System [GPS]) Runway (RWY) 4 Left (L) and Non-directional Beacon (NDB) RWY 4L IAPs were revised, rendering the airport's Class E airspace excessive. To better accommodate the procedures, the airspace footprint should be reduced.

The centralized radius of the airspace should be reduced to 4.2 miles and the northern portion removed, as circling is not authorized northwest of the airport and airspace containment is not necessary beyond 4.2 miles south of the airport. The eastern portion of Nenana's Class E airspace should be reduced to be a rectangular extension that would more appropriately contain arriving IFR aircraft conducting the missed approach portions of the airport's IAPs. The western extension should be shortened to more appropriately contain departing IFR aircraft executing the RWY 22 Right (R) obstacle departure procedure until reaching 1,200 feet above the surface and arriving IFR operations below 1,500 feet above the surface when executing the RNAV (GPS) RWY 4L approach procedure.

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. Therefore, it: (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:

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

VOCs and NO X contribute to the production of ground-level ozone, or smog, which harms human health and the environment. The EPA defines RACT as the lowest emission limit that a particular source is capable of meeting by the application of control technology that is reasonably available considering technological and economic feasibility. 1

Sections 182(b)(2) and 182(f) of the Clean Air Act (CAA), when taken together, require States to implement RACT for VOC and NO X in ozone nonattainment areas classified as Moderate (and higher). Specifically, these areas are required to implement RACT for all sources covered by a Control Techniques Guideline (CTG)  2 document, and for all major sources of VOCs and NO X in the area. For the purpose of RACT in Moderate ozone nonattainment areas, major sources of VOCs and NO X are those not covered by the applicability criteria in the CTGs (non-CTG) with the potential to emit (PTE) at least 100 tons per year.

To address non-CTG RACT requirements, Ohio adopted OAC rules 3745-21-11 and 3745-110-03(J), which require major VOC and NO X sources that are not covered by a CTG to submit detailed source-specific RACT studies analyzing the technological and economic feasibility of each available control measure. The purpose of these RACT studies is to provide technical support for Ohio's RACT determinations. Ohio EPA evaluated the information provided in the required studies, made a RACT determination for each major source, and submitted the RACT determinations to the EPA for incorporation into the Ohio SIP.

On June 4, 2018 (83 FR 25776), the EPA designated the Cleveland, OH nonattainment area and the Ohio portion of the Cincinnati, OH-KY nonattainment area as Marginal nonattainment areas for the 2015 ozone NAAQS. The Cleveland, OH nonattainment area consists of Cuyahoga, Geauga, Lake, Lorain, Medina, Portage, and Summit counties while the Ohio portion of the Cincinnati, OH-KY nonattainment area consists of Butler, Clermont, Hamilton, and Warren counties. On April 13, 2022 (87 FR 21849), pursuant to section 181(b)(2) of the CAA, the EPA proposed to determine that the Cleveland, OH nonattainment area failed to attain the 2015 ozone NAAQS by the August 3, 2021, Marginal area attainment deadline and thus proposed to reclassify the area from Marginal to Moderate nonattainment. In that action, the EPA proposed to establish January 1, 2023, as the due date for the State to submit all Moderate area nonattainment plan SIP requirements applicable to newly reclassified areas. The Ohio portion of the Cincinnati OH-KY 2015 ozone nonattainment area attained the 2015 ozone standard based on the 2019-2021 design value, and the area was redesignated to attainment effective June 9, 2022 (87 FR 35104).

Ohio has adopted regulations to address the NO X and VOC RACT requirements that apply to Moderate ozone nonattainment areas. Ohio has also voluntarily adopted rules for the Cincinnati Maintenance area as SIP strengthening measures, since planning efforts were underway to address Moderate RACT requirements for the 2015 ozone standard in Cleveland. The NO X RACT rules, in Chapter 3745-110 of the Ohio Administrative Code (OAC), effective March 25, 2022, apply to existing boilers, stationary combustion turbines, stationary internal combustion engines, reheat furnaces, and other sources at facilities that have an uncontrolled potential to emit 100 tpy or more of NO X . These rules apply to sources located in both the Cleveland nonattainment area (the EPA approved as RACT) and the Cincinnati maintenance area (the EPA approved as SIP strengthening) under the 2015 ozone standard.

Similarly, the VOC RACT rules, in Chapter 3745-21 of the OAC, effective March 27, 2022, apply to various VOC source categories in both the Cleveland nonattainment area and the Cincinnati maintenance area under the 2015 ozone standard. These rules cover both CTG sources and non-CTG major sources with an uncontrolled potential to emit 100 tons per year or more of VOCs.

Ohio EPA also adopted OAC Rules 3745-21-11 and 3745-110-03(J) and submitted them to the EPA for inclusion in the SIP. These rules require major non-CTG VOC and NO X sources located in ozone nonattainment areas classified as Moderate or higher to submit RACT studies to Ohio within one year of the rule's effective date. These RACT studies contain information on the technical and economic feasibility of VOC and NO X emission control measures to inform Ohio's RACT determinations for each major source.

On January 20, 2026 (91 FR 2308), the EPA approved portions of OAC Chapters 3745-21 and 3745-110 as satisfying certain Moderate VOC RACT and NO X RACT requirements for the Cleveland, OH nonattainment area under the 2015 ozone standard. The EPA also approved OAC 3745-21-11 and 3745-110-03(J) as SIP strengthening measures for the Cleveland nonattainment area under the 2015 ozone standard. Finally, the EPA approved OAC Chapter 3745-21 and 3745-110-03(J) as SIP strengthening for the Cincinnati Maintenance area under the 2015 ozone standard.

As a result, Ohio will be implementing NO X RACT in both Cleveland and Cincinnati, and NO X RACT will be federally enforceable in Cleveland. These rules will be SIP strengthening and go beyond what is required in the Cincinnati Maintenance Area at the Federal level, achieving additional emission reductions and contributing to maintenance of the ozone standard in this area.

The EPA is proposing to approve the RACT determinations submitted by Ohio for major sources in the Cleveland nonattainment area as meeting RACT requirements and to approve the SIP revisions submitted by Ohio for major sources in the Cincinnati maintenance area as SIP strengthening measures.

PPG Industries, Inc. (PPG) operates an automotive coatings manufacturing plant in Cleveland, Ohio. This facility is a major VOC source that is not covered by a CTG and has existing source-specific RACT established in OAC rule 3745-21-09(MM) under a previous ozone standard for VOC emissions from its paint manufacturing and associated paint laboratory operations (59 FR 23789). Ohio submitted this VOC RACT determination to the EPA on March 11, 2024. To control VOC emissions, the plant employs extensive capture systems and a large regenerative thermal oxidizer (RTO) system that treats emissions from entire buildings or groups of buildings. This setup ensures that all operations within these controlled buildings including the paint laboratory operations (K201) and paint manufacturing operations (P201), are subject to emission reduction measures. VOC emissions from the paint production equipment (P202) are not required to be routed to the RTO because the VOC emissions are low and VOC content is low or zero.

Under previously approved RACT requirements in OAC rule 3745-21-09(MM), VOC emissions from the paint laboratory (K201) must be vented to the RTO control system, which must achieve at least 90% control efficiency by weight or a maximum outlet VOC concentration of 20 parts per million by volume, dry (ppmvd). Also, paint manufacturing (P201) emissions must be vented to the RTO with a minimum control efficiency of 98% by weight, a maximum outlet VOC concentration of 20 ppmvd, or a minimum incineration temperature of one 1500 degrees Fahrenheit. The water-based paint production (P202) emissions unit is not required to have control equipment due to its low emissions levels, which are about one ton per year.

PPG conducted a VOC RACT analysis for this facility in accordance with OAC 3745-21-11. PPG evaluated the effectiveness of various alternative control technologies for the paint lab and manufacturing operations, including a carbon adsorber, thermal incinerator, catalytic incinerator, condenser, and scrubber, and found no technically feasible options that would achieve greater emission reductions than the existing RTO system. As a result, no cost-effectiveness estimates are provided.

For the paint lab operations, while it is technically feasible for an RTO to achieve a higher control efficiency than 90%, it is not technically feasible at this facility because the complex layout of approximately 260 pieces of equipment in nine paint laboratory buildings prevent PPG from achieving a higher capture efficiency. The entire building exhaust is routed to the RTO as opposed to controlling individual pollutant-emitting pieces of equipment.

For the water-based paint production unit, implementing a capture system is economically unreasonable given its low emission levels (1 tpy of VOC) and low VOC content (less than or equal to 12% VOC by weight), so RACT is continued compliance with OAC 3745-21-09(MM)(4). PPG's RACT study is available in docket for this action.

The EPA agrees that the existing RTO system is the most effective method for reducing VOC emissions at this facility. Therefore, the EPA concurs with Ohio's RACT determination and is proposing that for this facility, RACT is continued compliance with OAC 3745-21-09(MM).

The Formica Corporation facility in Evendale, Ohio, is located within the Cincinnati maintenance area under the 2015 ozone standard. The facility previously operated under a source-specific VOC RACT requirement in OAC 3745-21-09(PP) for its resin paper coaters/treaters (K003, K013, and K016). When the initial source-specific RACT for Formica was established, these units were not subject to the OAC rule 3745-21-09(F), which is based on the EPA's 2007 “Control Techniques Guidelines for Paper, Film, and Foil Coatings,” because the coatings were applied by dipping—an application method not then included in Ohio's definition of paper coating.

Since that time, Ohio has revised its definition to include dipping, making these units subject to the presumptive VOC RACT limits in OAC 3745-21-09(F). Although Cincinnati is in a maintenance area and not subject to RACT, OAC 3745-21-09(F) still applies, as its applicability includes Butler, Clermont, Hamilton, and Warren counties. As such, on April 23, 2024, Ohio submitted to the EPA a SIP revision seeking to remove the source-specific VOC RACT requirement for this facility and replace it with application of the presumptive rule as SIP strengthening.

The existing SIP approved source-specific VOC limit in OAC 3745-21-09(PP) is 0.9 lb VOC/gal of coating (excluding water and exempt solvents), while the VOC limit in OAC 3745-21-09(F) is 0.08 lb VOC/lb of coating.

Formica conducted a demonstration summarizing all resins used on the treaters and determined that all coatings comply with both the VOC limit in OAC 3745-21-09(F)(2) and the existing source-specific limit in OAC 3745-21-09(PP). This demonstration is available in the docket for this action.

Direct comparison of the limits in OAC 3745-21-09(PP) and OAC 3745-21-09(F)(2) is challenging because results depend on the coatings' water or solids content. However, in its demonstration, Formica also evaluated several coating formulations and found that those meeting the limit of 0.08 lb VOC/lb coating are equivalent to or more stringent than the existing source-specific limit of 0.9 lb VOC/gal (minus water).

Based on Formica's analysis, Ohio determined that this revision does not constitute backsliding because both limits achieve equivalent VOC reductions and actual emissions will not increase. The EPA concurs with Ohio's evaluation and is proposing to approve the removal of the site-specific VOC RACT rule for Formica in OAC 3745-21-09(PP), as these units are now regulated under the equivalent OAC 3745-21-09(F). The EPA has determined that this SIP revision will not interfere with attainment or maintenance of the NAAQS in accordance with section 110(l) of the CAA.

Owens Corning Roofing and Asphalt, LLC is a major non-CTG VOC source and operates a roofing and asphalt plant in the Cleveland nonattainment area under the 2015 ozone standard. Ohio submitted this VOC RACT determination to the EPA on January 22, 2025. Owens Corning's RACT study, which is available in the docket for this action, supports production limits, a vapor pressure limit for asphalt storage, and the continued use of an RTO and incinerators as satisfying RACT.

The plant manufactures asphalt shingles, with VOC emissions primarily generated from asphalt fumes during the roofing line coating processes. The uncontrolled VOC sources are the Laminate (3-wide) Roofing Line, Strip (4-wide) Roofing Line, and Asphalt Plant.

Owens Corning evaluated several add-on VOC control technologies for asphalt fumes, including thermal and catalytic incinerators, carbon adsorption, condensers, and scrubbers. Of these, only thermal incineration was found to be technically feasible.

Catalytic incinerators are not suitable because condensable portions of asphalt fumes foul and poison the catalyst, leading to extremely high replacement costs due to the presence of sulfur compounds. Carbon adsorption, while effective in removing low VOC concentrations, is infeasible because asphalt fumes would foul the carbon beds, reducing capacity, shortening bed life, and posing a fire hazard. Condensers are also technically infeasible because the high particulate content of asphalt fume exhaust would foul or plug the condenser tubes. Moreover, refrigerated condensers are only effective for exhaust streams with VOC concentrations above 5,000 ppm, while asphalt fume exhaust concentrations at this source are approximately 10 ppm.

Scrubbers are ineffective because many organic compounds in asphalt vapors are not water-soluble and would pass through untreated. Additionally, scrubber systems generate hazardous wastewater requiring off-site treatment. For these reasons, scrubbers are not used in practice to control asphalt fumes.

Based on this evaluation, thermal incineration was the only identified technically feasible add-on control technology for asphalt fume emissions. This conclusion is consistent with the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Area Sources: Asphalt Processing and Asphalt Roofing Manufacturing (40 CFR 63, subpart AAAAAAA), which identifies thermal oxidation as the applicable control device for particulate matter and polycyclic aromatic hydrocarbons (PAHs), which are also VOCs.

Existing VOC-controlled units—such as asphalt converters (Units P003, P004, P011, P012, P006/P013), storage tanks (Units T031, T032, T033), and loading racks (Units J001, J002, J003, J005)—are already controlled by incinerators or an RTO control device. The asphalt loading racks and storage tanks are already regulated by an RTO with a 95% control efficiency, required by Best Achievable Technology (BAT)  3 and NSPS for certain sources routed to the RTO. The asphalt converters are regulated by an incinerator with a 95% control efficiency, which are required by BAT and by the National Emission Standards for Hazardous Air Pollutants (NESHAP) for Asphalt Processing and Asphalt Roofing Manufacturing, 40 CFR 63, subpart 7A.

From a preliminary design analysis based on plant layout and process considerations of the Laminate (3-wide) Roofing Line and Strip (4-wide) Roofing Line and Asphalt Storage Tank, a minimum of four separate RTOs would be required to control all roofing lines. Installation of four RTOs is economically infeasible, with cost-effectiveness estimates ranging from $36,632 to $750,881 per ton of VOC removed.

Based on the analysis above, Ohio determined the following RACT Requirements for Owens Corning:

The EPA evaluated the study provided by Ohio (available in the docket) and concurs with Ohio's RACT determination. The alternative control technologies assessed are not technically feasible, and the existing controls and emission limits are sufficient to meet RACT requirements.

Therefore, the EPA is proposing to incorporate by reference the above RACT requirements from the following sections of permit number P0137247 (effective date: 01/06/2025)—B(11), B(12), B(13), B(14), C(1)(b)(1)(b), C(1)(c), C(1)(d), C(1)(e)(2), C(2)(b)(1)(b), C(2)(c), C(2)(d)(1), C(2)(e)(2), C(3)(b)(1)(b), C(3)(c), C(3)(d)(1), C(3)(e)(2), C(4)(b)(1)(b), C(4)(c), C(4)(d), C(4)(e)(2), C(5)(b)(1)(b), C(5)(c), C(5)(d)(3), C(5)(e)(2), C(6)(b)(1)(c), C(6)(d)(1), C(6)(e)(2), C(6)(f)(3),C(7)(b)(1)(b), C(7)(d)(1), C(7)(e)(2), C(7)(f)(2), C(8)(b)(1)(b), C(8)(c), C(8)(d)(1), C(8)(e)(2), C(9)(b)(1)(c), C(9)(c), C(9)(d)(1), C(9)(e)(2), C(10)(b)(1)(b), C(10)(d)(1), C(10)(e)(2), and C(10)(f)(2). See permit number P0137247 available in the docket for this action.

The General Electric Company, through its GE Aerospace business unit (GEA), operates a major industrial facility in Evendale, Ohio (Hamilton County). This facility is located in the Cincinnati 2015 ozone maintenance area so is not subject to RACT. Ohio submitted this SIP revision to the EPA on February 13, 2025.

The Evendale facility serves as GEA's headquarters and primary research and development (R&D) center, where it assembles and tests aircraft turbines (including military), aero-derivative turbines, and gas turbines. R&D operations include combustor technology test cells and various turbine and component tests for both commercial and military applications.

GEA has six robotic spray booths (K037-K042) and the EPA is proposing to approve a SIP revision from the State mandating that these six Robotic Coating Units (K037 through K042) comply with the VOC content limits in OAC rule 3745-21-19, which is based on the VOC CTG for Aerospace Manufacturing and Rework Facilities, as a SIP strengthening measure. Specifically, the EPA is proposing to approve a SIP revision requiring that these units comply with paragraphs (B), (D)(1), (D)(3), (D)(4), (D)(5), (E), (H), (J), and (K) of OAC rule 3745-21-19. Also, the EPA is proposing to approve a SIP strengthening revision that consists of good combustion practices for heating units (boilers) and operating under engineering test plans that minimize fuel use for turbine and component testing and ancillary operations.

The EPA is proposing to incorporate by reference the following sections of permit number P0136500 (effective date: 01/30/2025)—B(2), C(1)(b)(1)(c), C(1)(b)(2)(a), C(1)(c)(1), C(1)(d)(1), C(1)(e)(2); the EPA is also proposing to incorporate by reference the following sections of permit number P0136501 (effective date: 01/30/2025)—B(2), C(1)(b)(1)(f), C(1)(c)(2), C(1)(d)(2), C(1)(e)(3), C(2)(b)(1)(f), C(2)(c)(2), C(2)(d)(2), and C(2)(e)(3).

Akron Paint and Varnish (APV) is in the Cleveland, OH nonattainment area for the 2015 ozone standard and is a major non-CTG VOC source subject to RACT. Ohio submitted this VOC RACT determination to the EPA on January 15, 2025. APV manufactures custom-formulated paints and coatings, with most VOC emissions generated from mixing operations.

To control these VOC emissions, APV uses mixer covers that achieve over 99% VOC control efficiency. The mixers remain covered at all times except when loading materials. These covers significantly reduce solvent evaporation and fugitive VOC emissions.

APV evaluated several alternative VOC control technologies, including carbon adsorbers, catalytic incinerators, condensers, scrubbers, and thermal oxidizers. Carbon adsorbers are technically infeasible because they operate effectively only at VOC concentrations between 500 and 2,000 ppm, while APV's VOC concentrations are well below this range. Even under ideal conditions, carbon adsorbers typically achieve between 95 and 99% VOC control efficiency, which is lower than the over 99% control already achieved by the mixer covers in use.

Catalytic incinerators are also technically infeasible due to their sensitivity to variable inlet conditions and their tendency for catalyst fouling and deactivation by contaminants such as heavy metals, sulfur, phosphorus, and halogens. Condensers are not technically feasible because they are best suited for single organic compounds rather than the diverse VOC mixtures at APV. They also generate NO X emissions and would require additional NO X controls.

Scrubbers are not technically feasible due to their highly variable collection efficiency range (70-99%), generation of liquid waste, high maintenance requirements, and potential for plugging caused by particulate buildup. Thermal oxidizers are technically feasible and could achieve up to 98% VOC destruction efficiency, but are not economically reasonable, with an estimated cost-effectiveness of $123,385 per ton of VOC removed.

APV operates multiple production buildings equipped with several portable mixers that are relocated as needed to meet changing production demands. Installing a stationary control device, such as a thermal oxidizer, would eliminate the operational flexibility essential for APV's custom-batch manufacturing process, which involves varying product formulations and production volumes.

APV operates with good housekeeping practices, including keeping mixing and blending tanks covered except during necessary operations, cleaning them while enclosed to minimize VOC emissions, and maintaining a preventative maintenance program with regular equipment inspections. These practices also include promptly cleaning spills, storing waste in closed containers, and minimizing manual solvent transfers through hard piping.

Based on these considerations, Ohio has determined that APV's existing mixer covers are RACT. Because of the large number and mobility of mixers, it is not practical to enforce production limits on individual units. Therefore, Ohio has determined that VOC emissions controlled through facility-wide limits established in APV's Final Permit-to-Install and Operate (P0136483, effective December 11, 2024), which sets a total VOC emission limit of 99.9 tons per year, is an appropriate additional RACT limit.

The EPA concurs with Ohio's RACT determination and is proposing that APV's existing mixer covers, facility-wide 99.9 tpy limit of VOC, and good housekeeping practices satisfy RACT. These RACT requirements are contained in the following sections of Permit Number P0136483 (effective date: 12/11/2024), which the EPA is proposing to incorporate by reference into the Ohio SIP: B(8), C(3)(b)(1)(b), C(3)(c), C(3)(d)(4), C(3)(e)(4), C(3)(f)(2), C(4)(b)(1)(c), C(4)(c), C(4)(d)(1), C(4)(e)(6), C(4)(f)(2), C(5)(b)(1)(c), C(5)(c), C(5)(d)(1), C(5)(e)(6), and C(5)(f)(2).

Tyson Foods, Inc. is located in the Cincinnati, OH 2015 ozone maintenance area so is not currently subject to RACT. Ohio submitted this SIP revision to the EPA on June 24, 2025. Tyson operates a food processing facility that produces various cooked meat products. VOC emissions are generated from several processes, including boilers, heaters, emergency engines, and cooking lines-with the cooking lines being the primary source of VOC emissions.

In order to reduce VOC emissions from the cooking lines at this facility, Tyson's study recommends installing a new VOC emissions control system that includes multiple devices operating in series: First, each process line will be equipped with a mist eliminator; the exhaust from these units will be combined and routed through a secondary mist eliminator to further remove grease; finally, the combined exhaust will be controlled by an RTO. Ohio has submitted the requirement for this control system to be incorporated into the Ohio SIP.

The EPA agrees with Ohio's determination that the control system recommendation above is appropriate and is proposing to approve a SIP strengthening revision that consists of the installation of this combined mist eliminator and RTO system to control VOC emissions. The combined mist eliminator and RTO system is expected to achieve an overall VOC control efficiency of 98%. The EPA is proposing to incorporate by reference the following provisions of permit number P0137384 (effective date: 6/11/2025): B(3), C(1)(b)(1)(d), C(1)(c)(3), C(1)(d)(4), C(1)(e)(3), C(1)(f)(3), C(2)(b)(1)(d), C(2)(b)(1)(d), C(2)(c)(3), C(2)(d)(4), C(2)(e)(3), C(2)(f)(3), C(3)(b)(1)(d), C(3)(c)(2), C(3)(d)(5), C(3)(e)(3), C(3)(f)(3), C(4)(b)(1)(d), C(4)(c)(3), C(4)(d)(5), C(4)(e)(3), C(4)(f)(3), C(5)(b)(1)(d), C(5)(c)(3), C(5)(d)(5), C(5)(e)(3), C(5)(f)(3), C(6)(b)(1)(d), C(6)(c)(3), C(6)(d)(4), C(6)(e)(3), C(6)(f)(3), C(7)(b)(1)(d), C(7)(c)(3), C(7)(d)(4), C(7)(e)(3), and C(7)(f)(3).

U.S. Steel Seamless Tubular Operations, LLC—Lorain is a fully integrated tubular products manufacturing facility in Lorain County, located within the Cleveland 2015 ozone nonattainment area. The facility produces high-quality seamless pipe for the oil and gas and construction industries. It is a major source of NO X emissions and is therefore subject to RACT requirements under OAC 3745-110-03(J). Ohio submitted this NO X RACT determination to the EPA on March 28, 2024.

The facility operates under source-specific emission limits for NO X emissions from its tempering, rotary, and reheat furnaces as specified in OAC 3745-110-03(P), which is effective at the State level and the EPA is proposing to approve into the SIP. The applicable NO X emission limits are as follows: P003—0.068 lb/MMbtu, P035—0.12 lb/MMbtu, P037: 0.15 lb/MMbtu, P039—0.08 lb/MMbtu, P040—0.15 lb/MMbtu. U.S. Steel conducted a RACT analysis for emission units P003, P035, P037, P039, and P040. The No. 3 Seamless Mill rotary furnace (P035), No. 4 Seamless Mill rotary furnace (P039), and No. 4 Seamless Mill reheat furnace (P040) are recuperative furnaces. U.S. Steel evaluated selective catalytic reduction (SCR), selective non-catalytic reduction (SNCR), and low-NO X burners (LNBs) for these units. U.S. Steel submitted a detailed cost calculation contained in a Confidential Business Information document, which the EPA relied on for its RACT analysis.

The existing control technology for P035, P039, and P040 is LNBs. U.S. Steel assessed the economic feasibility of replacing the existing burners with newer LNBs capable of achieving 0.09 lb/MMBtu or less. The total cost-effectiveness ranged from $14,387 to $18,934 per ton of NO X removed, which is not economically feasible.

U.S. Steel also evaluated SCR installation on each recuperative furnace. The cost-effectiveness ranged from $20,285 to $38,871 per ton of NO X removed, which is not economically feasible.

SCR is also technically infeasible for these furnaces because their batch operation causes significant exhaust temperature fluctuations due to frequent door openings and closings. These variations prevent consistent SCR performance.

U.S. Steel also determined SNCR to be technically infeasible. Effective SNCR operation requires stable flue gas temperatures between 1600 °F and 2100 °F, while the recuperative furnaces operate at 600-1100 °F. Increasing temperatures to the required range would require significant natural gas use, resulting in high fuel costs and additional NO X emissions.

Because no other technically or economically feasible control options exist, Ohio determined that continued operation of the existing LNBs in compliance with OAC 3745-110-03(P) meets NO X RACT for the recuperative furnaces.

U.S. Steel also evaluated NO X controls for the No. 3 Seamless Mill Q&T tempering furnace (P003) and the No. 3 Seamless Mill No. 2 reheat furnace (P037), which are natural gas-fired, non-recuperative furnaces subject to NO X emission limits under OAC 3745-110-03(P). U.S. Steel examined SCR, SNCR, and LNBs for these units. The EPA is proposing to determine that OAC 3745-110-03(P)) meets RACT requirements for U.S. Steel for the 2015 ozone NAAQS.

SCR and SNCR are both technically infeasible for these furnaces because exhaust temperatures are not within the effective operating ranges. The flue gas temperature for P003 (1300 °F) is below the required SNCR range of 1600-2100 °F and would require reheating, which would increase NO X formation. Although P037 exhaust temperatures are near the lower end of the SNCR range (~1600 °F), achieving optimal NO X removal would still require additional reheating. Furthermore, the low uncontrolled NO X concentrations in these exhaust streams (approximately 19 ppm for P003 and 45 ppm for P037) would result in low overall removal efficiency, making SNCR technically infeasible.

LNBs are the existing control technology for both P003 and P037. U.S. Steel evaluated replacing the burners in P037 with newer LNBs capable of achieving 0.09 lb/MMBtu. P003 was not evaluated because it already meets this level. The cost-effectiveness for replacing the burners in P037 was $22,975 per ton of NO X removed, which is not economically feasible.

Given the absence of feasible alternatives, Ohio determined that continued operation of the existing LNBs meets NO X RACT for the non-recuperative furnaces. Ohio also determined that maintaining compliance with the limits in OAC 3745-110-03(P) for these units meets RACT for this source.

Therefore, the existing LNBs remain the only technically and economically feasible control option for both the recuperative and non-recuperative furnaces. Ohio determined that U.S. Steel's Lorain facility complies with the limits in OAC 3745-110-03(P), and the EPA concurs that this constitutes RACT under the 2015 ozone standard. The U.S. Steel RACT study is available in the docket for this action.

Charter Steel, located in Cuyahoga Heights, is located within the Cleveland 2015 ozone nonattainment area. The facility is a major source of NO X emissions and is therefore subject to RACT. Ohio submitted this NO X RACT determination to the EPA on December 5, 2023. Charter Steel's bar mill reheat furnace currently has a source-specific NO X limit of 0.11 lb/MMBtu established in OAC 3745-110-03(Q). This rule is not currently in the SIP and the EPA is proposing to determine that it meets RACT requirements for Charter Steel.

In accordance with OAC 3745-110-03(J), Charter Steel conducted a NO X RACT study for its bar mill reheat furnace (P029). The furnace uses natural gas burners to heat steel billets so they can be formed into steel rods or bars. Existing NO X combustion controls include LNBs that utilize staged combustion, exhaust gas recirculation, and low excess air to reduce peak flame temperatures and limit NO X formation.

As part of the study, Charter Steel evaluated the technical feasibility of various add-on NO X control technologies including SCR, SNCR, and NSCR. The reaction temperature required for SNCR is typically between 1,600 °F and 2,000 °F, while the furnace exhaust temperature is approximately 1,100 °F. Reheating the exhaust gases to the required temperature would result in additional NO X generation, negating the benefit of control and making SNCR technically infeasible. NSCR, which is used in rich-burn engines for the reduction of CO, VOCs, and NO X , is not applicable to low-excess-air natural gas burners and is therefore also not technically feasible. SCR is effective at temperatures between 650 °F and 800 °F, but the furnace exhaust gases are approximately 1,100 °F. Installing SCR before the heat recuperator would require cooling the gases to 800 °F and then reheating them, while installing it after the recuperator would require reheating the gases to 650 °F. Both options would increase natural gas combustion and NO X emissions, making SCR technically infeasible as well.

Because these alternative control technologies are highly temperature-dependent, none are technically feasible for the bar mill reheat furnace. The exhaust gas temperature of 1,100 °F is too low for SNCR and NSCR and too high for SCR. Consequently, Ohio determined that the existing low-NO X burners represent the most effective and practical method for controlling NO X emissions at this facility.

Based on the results of the NO X RACT study, the EPA concurs with Ohio's RACT determination and is proposing that operation of low-NO X burners, in compliance with OAC 3745-110-03(Q), constitutes RACT for the bar mill reheat furnace at Charter Steel. These existing controls represent the most effective means of reducing NO X emissions at this source. The Charter Steel RACT study is available in the docket for this action.

Carmeuse Lime, Inc. operates a lime manufacturing facility in Grand River, Ohio, within the Cleveland 2015 ozone nonattainment area. The facility is a major source of NO X and is subject to RACT. Ohio submitted this NO X RACT determination to the EPA on July 28, 2025. Its primary NO X emissions come from two rotary lime kilns (P001 and P002), currently limited under OAC 3745-110-03(S) to 6.0 lb NO X per ton of lime produced, which is effective at the State level. Carmeuse conducted a NO X RACT study in accordance with OAC 3745-110-03(J), included in the docket for this action.

Carmeuse evaluated several control technologies, including SCR, SNCR, mid-kiln firing, mid-kiln air injection, and low-NO X burners. SCR is infeasible due to high particulate and calcium in the exhaust, risk of catalyst poisoning, and flue gas temperatures (400-450 °F) below the optimal 700 °F, which would require costly reheating. SNCR is infeasible because the variable kiln temperature prevents maintaining the precise conditions needed for effective NO X reduction. Mid-kiln firing is unsuitable because the kilns operate at ~2,500 °F, far above the 1,100-1,650 °F required, and staged fuel feeding could increase CO emissions. Mid-kiln air injection could increase sulfur content in the product, and low-NO X burners would reduce calcining efficiency, increase fuel use, and provide minimal additional NO X reduction beyond current operations. Carmeuse's RACT study determined that the technically and economically feasible control method is proper kiln operation and good combustion practices, including minimizing excess air, controlling fuel injection, and maintaining optimal kiln temperatures. The facility monitors fuel usage, combustion air, burner zone temperatures, and oxygen to ensure efficient operation.

Based on stack testing, Carmeuse calculated a revised NO X limit of 4.6 lb per ton of lime for P001 and P002, representing the highest value from five stack tests plus a 20% contingency factor. This limit is more stringent than the existing 6.0 lb/ton limit in OAC 3745-110-03(S). Ohio determined that RACT is achieved through compliance with the 54.5 tons/hr maximum process weight rate and the 4.6 lb/ton NO X limit. The EPA concurs with Ohio's RACT determination and is proposing that the 4.6 lb/ton NO X limit, continued operation with good combustion practices, and the 54.5 tons/hr process weight rate constitute NO X RACT for this source.

The EPA is also proposing to incorporate by reference the following RACT provisions of permit number P0137844 (effective date: 07/10/2025): B(3)-B(7), C(1)(b)(1)(b), C(1)(c)(1), C(1)(d)(1), C(1)(e)(1), C(1)(f)(1)(a), C(2)(b)(1)(b), C(2)(c)(1), C(2)(d)(1), C(2)(e)(1), and C(2)(f)(1)(a).

Ross Incineration Services, Inc. (RIS) operates a hazardous waste incinerator in Grafton, Ohio, located within the Cleveland Moderate nonattainment area for the 2015 ozone NAAQS. The facility is subject to source-specific NO X limits under OAC 3745-110-03(T), which is effective at the State level. As a major NO X source, RIS is also subject to RACT under OAC 3745-110-03(J). Ohio submitted this NO X RACT determination to the EPA on August 25, 2025.

The incineration system includes a co-current rotary kiln (unit N001) and a countercurrent main combustion chamber. Both units are fueled by solid, sludge, or liquid waste, which serves as the heat source to maintain combustion temperatures. Air emissions from these chambers are treated by a quench, cyclone, radial flow wet scrubber, gas/liquid contactor, and two wet electrostatic precipitators (WESPs) before being vented through a stack.

RIS evaluated selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR) for post-combustion NO X control. The temperatures in the main combustion exceed the optimal range for SNCR. To achieve appropriate temperatures, the exhaust gas would require cooling via an added quench system with reagent injection and sufficient residence time. This would likely necessitate a major retrofit, such as adding a third combustion chamber. Therefore, SNCR is not technically feasible under the current configuration but is technically feasible with the retrofit previously described.

Downstream of the WESPs, flue gas temperatures are well below the temperatures required for SCR. In addition, trace heavy metals in the flue gas could poison the catalyst, leading to frequent and costly replacements. Given these factors, SCR is only technically feasible with significant new equipment.

Although both SNCR and SCR are theoretically technically feasible, neither is economically reasonable. The estimated SCR and SNCR costs range from approximately $10,000 to 19,000 per ton of NO X removed. Ross Incineration submitted a detailed cost calculation contained in a Confidential Business Information document, which the EPA relied on for its RACT analysis. In addition, due to the technical complexity of retrofitting a SNCR system on a highly regulated incinerator, and limited space with which to cool down the exhaust stream to a suitable temperature and residence times, SNCR costs are likely understated.

The RIS RACT study concluded that no additional control technology is both technically feasible and economically reasonable under OAC 3745-110-03(J). Instead, Ohio identified good combustion practices and lower NO X emission limits as RACT for this facility. The EPA concurs with this determination, defining RACT for RIS as operating the unit according to manufacturer specifications and good combustion practices, and a NO X emission limit of 105 lb/hr (30-day rolling average). The EPA is also proposing to approve (as a SIP strengthening measure) a SIP revision that includes a RACT reevaluation requirement: if NO X emissions from unit N001 exceed 110% of the baseline established in the RACT study (185.9 tons per year), RIS must complete a new RACT evaluation within one year.

The EPA is proposing to agree with Ohio EPA's RACT determinations at this facility and incorporate by reference the following RACT provisions of permit number P0137637 (effective date: 07/31/2025): C(1)(b)(1)(k), C(1)(b)(1)(L), (C)(1)(c)(19), (C)(1)(d)(54), (C)(1)(e)(20), (C)(1)(f)(1)(f).

The EPA is proposing to approve the following as meeting RACT in the Cleveland moderate nonattainment area under the 2015 ozone standard:

• PPG Industries Ohio, Inc.: Existing source-specific RACT in OAC 3745-21-09(MM).

• Owens Corning: Production limits, a vapor pressure limit for asphalt storage, and continued use of RTOs and incinerators, as detailed in the permit provisions described above.

• Akron Paint and Varnish: Facility-wide VOC limit of 99.9 tons per year and work practice standards, including the use of existing mixer covers, as reflected in the permit provisions described above.

• U.S. Steel Tubular Lorain: Operation of existing LNBs with compliance to emission limits in OAC 3745-110-03(P).

• Charter Steel: Operation of LNBs with compliance to emission limits in OAC 3745-110-03(Q).

• Carmeuse Lime: 4.6 lb/ton NO X limit for kilns, continued operation with good combustion practices, proper kiln operation, and a 54.5 tons/hr process weight rate limit, as detailed in the permit provisions above.

• Ross Incineration: Good operating and combustion practices to control NO X emissions. The NO X emission limit for the hazardous waste incinerator (unit N001) is 105 pounds per hour, based on a 30-day rolling average. If NO X emissions from unit N001 exceed 110% of the baseline established in the RACT study, a RACT reevaluation must be completed within one year. These RACT requirements are detailed in the permit provisions above.

The EPA is also proposing to approve the following actions as SIP strengthening for the Cincinnati maintenance area under the 2015 ozone standard:

• GE Evendale: Good operating practices for combustion units and operation under engineering test plans that minimize fuel use for turbine testing and ancillary operations. These measures are detailed permit provisions described above. Presumptive limits under OAC 3745-21-19 for robotic coaters.

• Tyson Foods: Installation of a combined mist eliminator and thermal oxidizer system achieving 98% VOC control efficiency from all cook lines, as reflected in the permit provisions above.

Finally, the EPA is proposing to approve the removal of the site-specific VOC RACT rule for Formica in OAC 3745-21-09(PP), as these units are now regulated under the equivalent CTG-based rule in OAC 3745-21-09(F).

In this rule, the EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference Ohio rule(s) 3745-21-09(MM), 3745-110-03(Q), and OAC 3745-110-03(P), discussed in section I of this preamble. The EPA has made, and will continue to make, these documents generally available through www.regulations.gov and at the EPA Region 5 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

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

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

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

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

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

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

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

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

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

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

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

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

This supplementary information section is arranged as follows:

On June 3, 2024, Illinois EPA submitted a revision to its SIP to address regional haze for the second implementation period. Illinois EPA submitted this SIP revision to satisfy the requirements of the CAA's regional haze program pursuant to CAA section 169A and 40 CFR 51.308. The EPA proposes to find that the Illinois regional haze SIP revision for the second implementation period meets the applicable statutory and regulatory requirements and thus proposes to approve the submission into Illinois' SIP.

On September 29, 2017, and May 16, 2019, Illinois EPA submitted SIP revisions addressing infrastructure requirements for the 2012 PM 2.5 NAAQS and the 2015 ozone NAAQS, respectively. The EPA proposes to approve both submissions as meeting CAA section 110(a)(2)(D)(i)(II), which requires a State's SIP to contain adequate provisions prohibiting emissions that will interfere with required visibility protection measures in any other State's SIP.

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. 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. 3 CAA 169A. The CAA establishes as a national goal the “prevention of any future, and the remedying of any existing, impairment of visibility in mandatory class I Federal areas which impairment results from manmade air pollution.” CAA 169A(a)(1). Regional haze is visibility impairment that is produced by a multitude of anthropogenic sources and activities 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 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);  5 see also 40 CFR 51.308(b), (f) (establishing submission dates for iterative regional haze SIP revisions); (64 FR 35714 at 35768, July 1, 1999).

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

Because the air pollutants and pollution affecting visibility in Class I areas can be transported over long distances, successful implementation of the regional haze program requires long-term, regional coordination among multiple jurisdictions and agencies that have responsibility for Class I areas and the emissions that impact visibility in those areas. To address regional haze, States need to develop strategies in coordination with one another, considering the effect of emissions from one jurisdiction on the air quality in another. Five regional planning organizations (RPOs), which include representation from State and Tribal governments, the EPA, and Federal Land Managers (FLMs), were developed in the lead-up to the first implementation period to address regional haze. RPOs evaluate technical information to better understand how emissions from State and Tribal land impact Class I areas across the country, pursue the development of regional strategies to reduce emissions of particulate matter and other pollutants leading to regional haze, and help States meet the consultation requirements of the RHR.

The Lake Michigan Air Directors Consortium (LADCO) is an RPO that includes the States of Illinois, Indiana, Michigan, Minnesota, Ohio, and Wisconsin. LADCO's work is a collaborative effort of State governments, Tribal governments, and various Federal agencies established to initiate and coordinate activities associated with the management of regional haze, visibility, and other air quality issues in the Midwest. Along with the six LADCO States, participants in LADCO's Regional Haze Technical Workgroup include the EPA, the U.S. National Park Service (NPS), the U.S. Fish and Wildlife Service (FWS), the U.S. Forest Service (USFS), regional Tribal air programs, and local air agencies.

Under the CAA and the 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  6 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).

In developing the regulations required by CAA section 169A(b), the EPA established the concept of the URP for each Class I area. The URP is 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. The URP is determined by drawing a straight line from the measured 2000-2004 baseline conditions (in deciviews) for the 20% most impaired days at each Class I area to the estimated natural conditions (in deciviews) for the 20% most impaired days in 2064. From this calculation, a URP value can be calculated for each year between 2004 and 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). The EPA developed the URP to address the diverse concerns of Eastern and Western States and account for the varying levels of visibility impairment in Class I areas around the country while ensuring an equitable approach nationwide. For each Class I area, States must calculate the URP for the end of each implementation period ( e.g., in 2028 for the second implementation period). 7 40 CFR 51.308(f)(1)(vi)(A). States may also adjust the URP to account for impacts from anthropogenic sources outside the United States and/or impacts from certain wildland prescribed fires. 40 CFR 51.308(f)(1)(vi).

Each State having a Class I area and/or emissions that may affect visibility in a Class I area must then develop a long-term strategy that includes the enforceable emission limitations, compliance schedules, and other measures that are necessary to make reasonable progress in such areas. A reasonable progress determination is based on applying the four factors in CAA section 169A(g)(1) to sources of visibility impairing pollutants that the State has selected to assess for controls for the second implementation period. Additionally, as further explained below, the RHR at 40 CFR 51.308(f)(2)(iv) separately provides five “additional factors”  8 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 RPGs for each Class I area within its borders by modeling the visibility impacts of all reasonable progress controls at the end of the second implementation period, i.e., in 2028, as well as the impacts of other requirements of the CAA. The RPGs include reasonable progress controls not only for sources in the State in which the Class I area is located, but also for sources in other States that contribute to visibility impairment in that area. The RPGs are then compared to the baseline visibility conditions and the URP to ensure that progress is being made towards the statutory goal of preventing any future and remedying any existing anthropogenic visibility impairment in Class I areas. 40 CFR 51.308(f)(2)-(3). For each Class I area, States must compare the RPG for the 20% most impaired days to the URP for the end of the implementation period. If the RPG is above the URP, then an additional “robust demonstration” requirement is triggered for each State that contributes to that Class I area. 40 CFR 51.308(f)(3)(ii). There are additional requirements in the rule, including FLM consultation, that apply to all visibility protection SIPs and SIP revisions. See e.g., 40 CFR 51.308(i).

While States have discretion to choose any source selection methodology that is reasonable, whatever choices they make should be reasonably explained. To this end, 40 CFR 51.308(f)(2)(i) requires that a State's SIP submission include “a description of the criteria it used to determine which sources or groups of sources it evaluated.” The technical basis for source selection, which may include methods for quantifying potential visibility impacts such as emissions divided by distance metrics, trajectory analyses, residence time analyses, and/or photochemical modeling, must also be appropriately documented, as required by 40 CFR 51.308(f)(2)(iii).

Once a State has selected the set of sources, the next step is to determine the emissions reduction measures for those sources that are necessary to make reasonable progress for the second implementation period. 9 This is accomplished by considering the four factors—“the costs of compliance, the time necessary for compliance, and the energy and nonair quality environmental impacts of compliance, and the remaining useful life of any existing source subject to such requirements.” CAA 169A(g)(1). The EPA has explained that the four-factor analysis is an assessment of potential emission reduction measures ( i.e., control options) for sources; “use of the terms ‘compliance’ and ‘subject to such requirements’ in section 169A(g)(1) strongly indicates that Congress intended the relevant determination to be the requirements with which sources would have to comply to satisfy the CAA's reasonable progress mandate.” 82 FR 3078 at 3091, January 10, 2017. Thus, for each source it has selected for four-factor analysis, 10 a State must consider a “meaningful set” of technically feasible control options for reducing emissions of visibility impairing pollutants. Id. at 3088.

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. 11 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. 12 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”  13 that States must consider in developing their long-term strategies: (1) Emission reductions due to ongoing air pollution control programs, including measures to address reasonably attributable visibility impairment; (2) measures to reduce the impacts of construction activities; (3) source retirement and replacement schedules; (4) basic smoke management practices for prescribed fire used for agricultural and wildland vegetation management purposes and smoke management programs; and (5) the anticipated net effect on visibility due to projected changes in point, area, and mobile source emissions over the period addressed by the long-term strategy.

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

Reasonable progress goals “measure the progress that is projected to be achieved by the control measures States have determined are necessary to make reasonable progress based on a four-factor analysis.” 82 FR 3078 at 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), (f)(6)(iv). All States' SIPs must provide for procedures by which monitoring data and other information are used to determine the contribution of emissions from within the State to regional haze visibility impairment in affected Class I areas, as well as a statewide inventory documenting such emissions. 40 CFR 51.308(f)(6)(ii), (iii), (v). All States' SIPs must also provide for any other elements, including reporting, recordkeeping, and other measures, that are necessary for States to assess and report on visibility. 40 CFR 51.308(f)(6)(vi).

Section 51.308(f)(5) requires a State's regional haze SIP revision to address the requirements of paragraphs 40 CFR 51.308(g)(1) through (5) so that the plan revision due in 2021 will serve also as a progress report addressing the period since submission of the progress report for the first implementation period. The regional haze progress report requirement is designed to inform the public and the EPA about a State's implementation of its existing long-term strategy and whether such implementation is in fact resulting in the expected visibility improvement. See 81 FR 26942, 26950 (May 4, 2016), (82 FR 3078 at 3119, January 10, 2017). To this end, every State's SIP revision for the second implementation period is required to assess changes in visibility conditions and describe the status of implementation of all measures included in the State's long-term strategy, including 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).

For the first implementation period covering the years 2007 through 2018, Illinois EPA submitted its regional haze SIP to the EPA on June 24, 2011, and the EPA approved it on May 29, 2012. See 77 FR 39943, July 6, 2012. The requirements for regional haze SIPs for the first implementation period are contained in 40 CFR 51.308(d) and (e).

Pursuant to 40 CFR 51.308(g), Illinois was also responsible for submitting a five-year progress report as a SIP revision for the first implementation period. On February 2, 2017, Illinois EPA submitted the progress report. The EPA approved this five-year progress report as a revision to the Illinois SIP at 40 CFR 52.720(e) on April 3, 2018. See 83 FR 15744, April 12, 2018.

In accordance with section 169A of the CAA and the RHR at 40 CFR 51.308(f), Illinois EPA submitted a revision to the Illinois SIP on June 3, 2024, to address its regional haze obligations for the second implementation period, which runs through 2028. 14 In developing its 2024 SIP revision, Illinois EPA initiated an FLM consultation process and provided a public comment period for the second implementation period. The public comment period on the 2024 SIP revision ran from January 19, 2024, through March 21, 2024, and a public hearing was held on February 27, 2024. Illinois EPA received and responded to comments from FLMs and the public. Illinois EPA summarized and responded to the FLMs' comments in appendix H to the 2024 SIP submission. Illinois EPA included the public comments and its responses in attachments 3 and 4 to the 2024 SIP submission.

Prior to submitting its 2024 regional haze SIP revision and during the second implementation period, Illinois adopted amendments to its Multi-Pollutant Standards (MPS) Rule on August 22, 2019, 15 and submitted the amended MPS Rule to the EPA as a revision to its regional haze SIP on January 23, 2020. The EPA approved the revision on June 14, 2021, and revised Illinois' SIP at 40 CFR 52.720(c). 86 FR 13260, March 8, 2021, and 86 FR 33527, June 25, 2021. The MPS Rule established fleet-wide SO 2 and NO X emission limits for electric generating units (EGUs) and fulfilled the BART requirements of the first implementation period. The provisions of the MPS Rule are further described in section IV of Illinois' 2024 SIP submission and in section 2.1 of the EPA's November 12, 2025, Technical Support Document (TSD) for this proposed rulemaking, which is included in the docket.

The following sections describe Illinois' 2024 SIP submission, including Illinois EPA's assessment of progress made since the first implementation period in reducing emissions of visibility impairing pollutants and of the visibility improvement progress at nearby Class I areas. This notice of proposed rulemaking also contains the EPA's evaluation of Illinois' 2024 SIP submission against the requirements of the CAA and the RHR for the second implementation period of the regional haze program.

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

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 at 35721, July 1, 1999, 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.

Illinois has no Class I areas within its borders that are among the 156 mandatory Class I Federal areas where the EPA deemed visibility to be an important value. See 40 CFR part 81, subpart D. Thus, Illinois EPA only evaluated the State's impact on out-of-State mandatory Class I Federal areas covered under the RHR.

Illinois EPA is a member of LADCO and participated in the development of LADCO's strategy for making reasonable progress towards the national visibility goal in the Class I areas. To identify Class I areas where progress toward natural visibility conditions may be impacted by emissions from sources in Illinois, Illinois EPA reviewed technical analyses conducted by LADCO. This included the technical analyses from the first implementation period compiled in 2007 by LADCO, known as the Midwest RPO at the time, to determine which Class I areas outside the State were affected by emission sources in Illinois. 16 These analyses included LADCO's back trajectory analysis and Comprehensive Air Quality Model with extensions and its Particulate Matter Source Apportionment Tool (CAMx-PSAT) as well as MANE-VU's contribution assessment, 17 Missouri-Arkansas' Contribution Assessment, VISTAS' Areas of Influence Analysis, 18 and WRAP's back trajectories and modeling. 19 Using LADCO's back trajectory analysis, LADCO initially assumed a State affected visibility impairment in a Class I area if it was projected to contribute two percent or more to the total light extinction. This threshold accounted for about 90-95 percent of the total light extinction at the Class I areas. Based on analyses conducted by other RPOs, LADCO gave deference to the criteria established by each RPO to identify additional Class I areas affected by LADCO States.

For the second regional haze implementation period, Illinois EPA reviewed later analyses by LADCO that also used CAMx-PSAT. 20 In its 2017 analyses, LADCO tagged States and regions as well as individual point sources and inventory source groups to apportion emissions to States and regions. LADCO assessed relative visibility impacts in 2028 by projecting representative emissions inventories and known emission controls from 2016. In 2017, a group of RPOs, States, and the EPA established 2016 as the base year for a national air quality modeling platform for future ozone, PM 2.5 , and regional haze SIP development because that year had typical ozone and wildfire conditions. 21 LADCO relied upon the EPA's inventory estimates for 2016 and 2028 for most emission sectors as described in the EPA's September 19, 2019, “Availability of Modeling Data and Associated Technical Support Document for the EPA's Updated 2028 Visibility Air Quality Modeling,” (EPA's Updated 2028 Visibility Air Quality Modeling TSD). 22 For EGU emissions, LADCO used forecasts from the Eastern Regional Technical Advisory Committee (ERTAC) based on continuous emissions monitoring data from 2016 instead of the Integrated Planning Model used in the EPA's 2016 modeling platform. LADCO also incorporated State-reported changes to EGUs received through September 2020 to estimate 2028 EGU emissions.

Based on LADCO's 2007 and 2017 analyses, 23 Illinois EPA used the list of sources from the first implementation period to identify 16 Class I areas affected by emission sources in Illinois in the second implementation period. These Class I areas are: Boundary Waters Canoe Area Wilderness, Brigantine Wilderness Area, Caney Creek Wilderness Area, Great Gulf Wilderness Area, Great Smoky Mountains National Park, Hercules-Glades Wilderness Area, Isle Royale National Park, Lye Brook Wilderness, Acadia National Park, Mammoth Cave National Park, Mingo Wilderness Area, Moosehorn Wilderness Area, Seney Wilderness Area, Sipsey Wilderness Area, Upper Buffalo Wilderness Area, and Voyageurs National Park. 24 Illinois EPA characterized the list as conservative because emissions of visibility-impairing pollutants from sources in Illinois have declined since the first implementation period. 2028 visibility conditions at these Class I areas are projected by both LADCO and the EPA to be below the adjusted and unadjusted URP glidepaths provided in the EPA's Updated 2028 Visibility Air Quality Modeling TSD. These projections are depicted in Table 3.1 of Illinois' SIP submission and Table 8 of the EPA's November 12, 2025, TSD. Illinois EPA notes that the 2028 projections do not account for the 2019 revisions to the MPS, many emission reductions that have already taken place during the second implementation period, or all elements of Illinois' long-term strategy. As such, Illinois EPA anticipates greater improvements in visibility than those modeled in the projections by the EPA and LADCO.

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).

Illinois has no mandatory Class I areas within its borders to which the requirements of the visibility protection program apply in 40 CFR part 81, subpart D. Therefore, 40 CFR 51.308(f)(1) and its requirements do not apply.

Each State having a Class I area within its borders or emissions that may affect visibility in a Class I area must develop a long-term strategy for making reasonable progress towards the national visibility goal. CAA 169A(b)(2)(B). After considering the four statutory factors, all measures that are determined to be necessary to make reasonable progress must be in the long-term strategy. In developing its long-term strategies, a State must also consider the five additional factors in 40 CFR 51.308(f)(2)(iv). As part of its reasonable progress determinations, the State must describe the criteria used to determine which sources or group of sources were evaluated ( i.e., subjected to four-factor analysis) for the second implementation period and how the four factors were taken into consideration in selecting the emission reduction measures for inclusion in the long-term strategy. 40 CFR 51.308(f)(2)(iii).

The provisions of 40 CFR 51.308(f)(2)(i) require States to describe the criteria used to determine which sources or groups of sources that State evaluated for potential emission reduction measures. States may rely on technical information developed by the RPOs of which they are members to select sources for four-factor analysis and to conduct that analysis, as well as to satisfy the documentation requirements under 40 CFR 51.308(f).

Illinois EPA described its source selection process in section IV of the 2024 SIP submission. In selecting sources to evaluate for potential control measure additions during the second implementation period, Illinois EPA considered SO 2 , NO X , VOC, NH 3 , and direct PM emissions but focused on NO X and SO 2 emissions following an analysis of IMPROVE data performed by LADCO. This analysis, described in LADCO's Technical Support Document “Modeling and Analysis for Demonstrating Reasonable Progress for the Regional Haze Rule 2018-2028 Planning Period,” (LADCO's 2021 TSD), 25 dated June 17, 2021, demonstrated that ammonium sulfate and ammonium nitrate are the largest components of haze during the most impaired days at the LADCO Class I areas. The LADCO Class I areas consist of Boundary Waters Canoe Area Wilderness and Voyageurs National Park in Minnesota and Isle Royale National Park and Seney Wilderness Area in Michigan. As precursors to ammonium sulfate and ammonium nitrate particulates, SO 2 , and NO X , and NH 3 emissions contribute more to visibility impairment in the LADCO Class I Areas than direct PM 2.5 and VOC emissions. Illinois EPA determined that focusing on potential reductions in NO X and SO 2 emissions would be the most effective approach for the second implementation period. The EPA finds this approach to be reasonable, as noted in the “Guidance on Regional Haze State Implementation Plans for the Second Implementation Period,” EPA Office of Air Quality Planning and Standards, Research Triangle Park, August 20, 2019 (“2019 Regional Haze Guidance”) at page 12. 26 Illinois decided to focus specifically on NO X and SO 2 emissions from point sources based on information in the EPA's Updated 2028 Visibility Air Quality Modeling TSD, which provided a percentage breakdown of contributions to Class I areas by source sectors, such as point EGU point, non-EGU, nonpoint point, onroad, oil and gas, residential wood combustion, and anthropogenic dust. Table 4.1 of Illinois' 2024 SIP submission includes the percentage contributions to Class I areas affected by Illinois. The EGU and non-EGU point source sector emissions contribute the largest percentage, an average of 56 percent, of the visibility impairment in the Class I areas affected by Illinois. The EPA finds that Illinois EPA's decision to focus on NO X and SO 2 emissions from point sources is further supported by Tables 4-2 and 4-7 of LADCO's 2021 TSD, which show that emissions from point sources account for a large portion of both NO X and SO 2 emissions in Illinois, whereas NH 3 , the third precursor to ammonium nitrate and ammonium sulfate, is mostly emitted from nonpoint sources.

Illinois EPA selected point sources for potential four-factor analyses based on LADCO's analyses of National Emissions Inventory (NEI) data. LADCO generated source lists based on total process-level emissions of NO X , SO 2 , PM 2.5 , and NH 3 (Q) divided by distance (d) to the center of the nearest Class I area, where Q/d was used as a surrogate quantitative metric of visibility impact in lieu of air quality modeling. The National Emissions Inventory Collaborative 2016 alpha inventory was selected in 2018 by the LADCO Regional Haze Technical Workgroup for the Q/d analysis as the best available inventory at that time. In support of using the 2016 data, Illinois EPA confirmed that there have been no emissions increases large enough to make use of the 2016 data inappropriate, especially since 2014-2020 NEI data demonstrates decreasing trends in NO X , PM 2.5 , and SO 2 emissions. 27 For details on the data and methods used in the Q/d analysis, see LADCO's October 14, 2020, technical memorandum “Description of the Sources and Methods Used to Support Q/d Analysis for the 2nd Regional Haze Planning Period”  28 and section 5 of LADCO's 2021 TSD.

Illinois EPA designed its source selection methodology to capture a meaningful portion of Illinois' total contribution to visibility impairment in the Class I areas, including the largest sources in the State. Illinois EPA initially set a unit-level Q/d threshold of four to begin identifying point source emission units for potentially cost-effective control additions, where Q reflected LADCO's 2028 projections from the 2016 base year sum of NO X , SO 2 , PM 2.5 , and NH 3 emissions. To focus on sources with the greatest visibility impact, Illinois EPA then grouped those units by source and identified units with Q/d greater than four at facilities with Q/d greater than 10 for potential four-factor analyses. This resulted in a list of 30 units, accounting for 71.4 percent of all emissions of SO 2 , NO X , NH 3 , and PM 2.5 from units with Q/d greater than one in Illinois, including all the largest sources. Of these 30 units, 14 are no longer operating:

Illinois EPA then determined that the existing controls on the following seven units are effective to the extent that a full four-factor analysis would likely result in a conclusion that no further controls are necessary.

Illinois EPA then selected the remaining nine units for four-factor analyses:

The demonstrations of existing effective controls and four-factor analyses are addressed under sections IV.E.2 and IV.E.4 of this preamble. Further details on Illinois EPA's source selection process, past retirements, demonstrations of existing effective controls, and four factor analyses are addressed in sections III, IV, V, and VI and appendix A of Illinois' 2024 SIP submission and sections 2 and 3 of the EPA's November 12, 2025, TSD.

The provisions of 40 CFR 51.308(f)(2)(i) require States to evaluate and determine the emission reduction measures that are necessary to make reasonable progress by applying the four statutory factors to sources in a control analysis. The emission reduction measures that are necessary to make reasonable progress must be included in the long-term strategy. 40 CFR 51.308(f)(2).

As mentioned above, Illinois EPA demonstrated that the seven units at Baldwin, Newton, Powerton, and Kincaid have existing effective control measures. Illinois EPA cited requirements contained in the MPS, the Combined Pollutant Standards (CPS), 31 and permits as well as 2016-2022 annual NO X and SO 2 emissions data to show that each unit has consistently implemented its existing measures and has achieved reasonably consistent annual emission rates that are not projected to increase in the future. For Baldwin, Newton, and Powerton, Illinois found that the existing measures under the MPS and CPS are necessary for reasonable progress for the second implementation period and documented that they form a part of the long-term strategy, are already federally enforceable and permanent, and are already included in the regulatory portion of Illinois' SIP at 40 CFR 52.720. For Kincaid, Illinois EPA referred to the existing BART measures that were previously included in the long-term strategy developed in the first implementation period. See 77 FR 3966, January 26, 2012. As such, Illinois EPA determined that additional control measures for the seven units at Baldwin, Newton, Powerton, and Kincaid are not necessary to make reasonable progress in the second implementation period. Illinois EPA's demonstrations of existing effective controls for these units are further described in section 3.3 of the EPA's November 12, 2025, TSD.

For the nine units at Prairie State, Marion, Rain CII Carbon, Lafarge Midwest, and Archer Daniels Midland, Illinois EPA provided a four-factor analysis as summarized in section V of Illinois' 2024 SIP submission and section 4 of the EPA's November 12, 2025, TSD. Appendix A to Illinois' submission describes the four-factor analyses in detail. Each analysis considered all four statutory factors and appropriately followed the methods in the EPA Air Pollution Control Cost Manual. 32 As presented in Table 1, Illinois EPA documented the range of cost effectiveness of potential new controls that were determined to be technically feasible.

For each unit, Illinois EPA determined that additional control measures are not necessary to make reasonable progress in the second implementation period and that pursuing additional emission reductions through new emission control equipment or emissions limitations is not cost-effective. Illinois EPA determined this based on the units' existing controls, the cost of the alternative control measures, and the remaining useful life of the units. Illinois EPA also concluded that the existing emission control measures for each of these units are not necessary for reasonable progress for the second implementation period and do not need to be included in the regulatory portion of the SIP beyond where they are already included. Illinois EPA determined this based on the limits in the sources' air permits, historical data showing relatively consistent or declining NO X and SO 2 annual emissions, recent unit emission rates, and the 2028 projections of overall emissions showing that emissions are not expected to increase in the future.

Each State's long-term strategy must include the enforceable emission limitations, compliance schedules, and other measures that are necessary to make reasonable progress. 40 CFR 51.308(f)(2). After considering information regarding existing effective controls, the four statutory factors in 40 CFR 51.308(f)(2)(i), and the five additional factors in 40 CFR 51.308(f)(2)(iv) in addition to other requirements in 40 CFR 51.308(f)(2)(ii) described below, Illinois EPA developed its long-term strategy for the second implementation period. Illinois EPA's long-term strategy is provided in section VI of Illinois' 2024 SIP submission and lists, at the State's discretion, measures beyond what the State deemed necessary for reasonable progress. Illinois EPA's long-term strategy lists State regulations such as the NO X Reasonably Available Control Technology (RACT) standards  33 as well as State regulations that are included in the regulatory part of Illinois' SIP at 40 CFR 52.720 for the MPS, 34 CPS, 35 and emission standards and limitations for Stationary Reciprocating Internal Combustion Engines (RICE) and Turbines. 36 Additionally, Illinois EPA's long-term strategy lists Federal measures for point sources including the Revised Cross-State Air Pollution Rule Update, 37 New Source Performance Standards (NSPS), 38 and National Emission Standards for Hazardous Air Pollutants (NESHAP), 39 as well as several Federal measures for area sources and on-road and non-road mobile sources. Of all the measures in the list, Illinois EPA only specified the State regulations for the MPS, CPS, and Stationary RICE and Turbines as necessary for reasonable progress in the second implementation period and reiterated that those measures are part of Illinois' SIP under 40 CFR 52.720, thus already federally enforceable and permanent. Illinois EPA did not identify any additional control requirements necessary for reasonable progress or any additional measures to be incorporated by reference into the regulatory portion of Illinois' SIP.

The EPA proposes to find that Illinois has satisfied the requirements of 40 CFR 51.308(f)(2)(i) related to evaluating sources and determining the emission reduction measures that are necessary to make reasonable progress by considering the four statutory factors. The EPA is basing this proposed finding on the State's examination of its largest sources as described above. The State considered the four statutory factors, the historical emissions data, the emission reductions that have already taken place during the second implementation period, and the current control measures. As summarized above and further described in the EPA's November 12, 2025, TSD, Illinois' selection of sources and evaluation of control measures was reasonable and consistent with the requirements of 40 CFR 51.308(f)(2)(i).

In addition, as recently announced and applied in the approval of the West Virginia regional haze SIP submittal, 40 it is the EPA's policy that, where visibility conditions for a Class I area impacted by a State are below the URP and the State has considered the four statutory factors, the State will have presumptively demonstrated reasonable progress for the second implementation period for that Class I area. The EPA has the discretion and authority to change policy. In FCC v. Fox Television Stations, Inc., the U.S. Supreme Court plainly stated that an agency is free to change a prior policy and “need not demonstrate . . . that the reasons for the new policy are better than the reasons for the old one; it suffices that the new policy is permissible under the statute, that there are good reasons for it, and that the agency believes it to be better.” 566 U.S. 502, 515 (2009) (referencing Motor Vehicle Mfrs. Ass'n of United States, Inc. v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29 (1983)). See also Perez v. Mortgage Bankers Assn., 135 S. Ct. 1199 (2015). The EPA believes that its recently adopted policy aligns with the purpose of the statute and RHR, which is achieving “reasonable” progress, not maximal progress, toward Congress' natural visibility goal.

In the 2017 RHR Revisions, the EPA addressed the role of the URP as it relates to a State's development of its second implementation period SIP. 82 FR 3078 (January 10, 2017). Specifically, in response to comments suggesting that the URP should be considered a “safe harbor” that relieve States of any obligation to consider the four statutory factors, the EPA explained that the URP was not intended to be such a safe harbor. Id. at 3099. “Some commenters stated a desire for corresponding rule text dealing with situations where RPGs are equal to (“on”) or better than (“below”) the URP or glidepath. Several commenters stated that the URP or glidepath should be a `safe harbor,' opining that States should be permitted to analyze whether projected visibility conditions for the end of the implementation period will be on or below the glidepath based on on-the-books or on-the-way control measures, and that in such cases a four-factor analysis should not be required.” Id.

Other 2017 RHR comments indicated a similar approach, such as “a somewhat narrower entrance to a `safe harbor,' ” by suggesting that if current visibility conditions are already below the end-of-planning-period point on the URP line, a four-factor analysis should not be required.” Id. The EPA stated in its response that we did not agree with either of these recommendations. “The CAA requires that each SIP revision contain long-term strategies for making reasonable progress, and that in determining reasonable progress states must consider the four statutory factors. Treating the URP as a safe harbor would be inconsistent with the statutory requirement that states assess the potential to make further reasonable progress towards natural visibility goal in every implementation period.” Id.

However, so long as a State considers the four factors, the presumption that a Class I area below the URP is achieving reasonable progress is consistent with the CAA and RHR. Indeed, we believe this policy also recognizes the considerable improvements in visibility impairment that have been made by a wide variety of State and Federal programs in recent decades. In sum, Illinois EPA selected a number of sources, evaluated emissions control measures, and considered the four statutory factors. In addition, as discussed in section 6 of the EPA's November 12, 2025, TSD, visibility conditions at all Class I areas to which Illinois contributes are below the URP. In light of these facts, this policy also supports the EPA's proposed finding that Illinois reasonably concluded that no additional measures are necessary to achieve reasonable progress during the second implementation period.

The consultation requirements of 40 CFR 51.308(f)(2)(ii) provide that States must consult with other States that are reasonably anticipated to contribute to visibility impairment in a Class I area to develop coordinated emission management strategies containing the emission reductions measures that are necessary to make reasonable progress. Section 51.308(f)(2)(ii)(A) and (B) require States to consider the emission reduction measures identified by other States as necessary for reasonable progress and to include agreed upon measures in their SIPs, respectively. Section 51.308(f)(2)(ii)(C) speaks to what happens if States cannot agree on what measures are necessary to make reasonable progress. States may also satisfy the requirement of 40 CFR 51.308(f)(2)(ii) to engage in interstate consultation with other States that have emissions that are reasonably anticipated to contribute to visibility impairment in a given Class I area under the auspices of intra- and inter-RPO engagement.

Although Illinois has no mandatory Class I Federal areas within its borders, emissions from sources within Illinois influence visibility at mandatory Class I Federal areas. Through intra- and inter-RPO engagement, Illinois EPA consulted with other States to develop a coordinated emission management approach to its regional haze SIP and to address Illinois' impact on nearby Class I areas. Consultation within LADCO and between LADCO and neighboring RPOs, including CenSARA  41 and VISTAS, 42 developed the technical information needed for such coordinated strategies. Inter-RPO cooperation is evident in LADCO's 2021 TSD and accompanying electronic docket, 43 which include area of influence modeling contributed by CenSARA and analyses for all Class I areas performed by LADCO.

Illinois EPA also received and responded to requests from MANE-VU, 44 Arkansas, 45 and Missouri  46 regarding regional haze. MANE-VU requested that Illinois ensure emission controls be operated year-round on certain EGUs and that Illinois pursue an ultra-low sulfur fuel oil standard. Illinois EPA replied that it already requires consistent NO X and SO 2 controls as well as an ultra-low sulfur fuel oil standard. In response to MANE-VU's request regarding the pursuit of energy initiatives, Illinois EPA noted Illinois' priorities on energy efficiency and other clean energy technologies. Arkansas requested that Illinois perform a four-factor analysis of Prairie State Generating Station because of its anticipated impact on visibility in the Upper Buffalo Wilderness Area. Illinois EPA replied that it would perform a four-factor analysis on this source. Missouri requested that Illinois consider performing four-factor analyses on Electric Energy Inc.—Joppa, Prairie State Generating Station, Southern Illinois Power Cooperative—Marion, and Dynegy Midwest Generation LLC—Baldwin. Illinois EPA addressed these sources in its 2024 SIP submission and cooperated with Missouri through LADCO and CenSARA. Illinois EPA did not receive any replies disagreeing with its responses. Section XIII of Illinois' SIP submission and section 5 of the EPA's November 12, 2025, TSD provide detailed summaries of Illinois' consultation with States, Tribes, and RPOs.

The EPA proposes to find that Illinois has satisfied the consultation requirements of 40 CFR 51.308(f)(2)(ii). Illinois has met the 40 CFR 51.308(f)(2)(ii)(A) and (B) requirements with its participation in the LADCO consultation process plus its individual communication with contributing States and RPOs. There were no disagreements with any other State, therefore 40 CFR 51.308(f)(2)(ii)(C) does not apply to Illinois.

The requirements of 40 CFR 51.308(f)(2)(iii) provide that a State must document the technical basis for its decision making to determine the emission reduction measures that are necessary to make reasonable progress. The documentation requirement of 40 CFR 51.308(f)(2)(iii) provides that States may meet their obligations to document the technical bases on which they are relying to determine the emission reductions measures that are necessary to make reasonable progress through an RPO, as long as the process has been “approved by all State participants.”

Illinois EPA adequately documented the technical basis that it relied on in determining the emission reduction measures that are necessary to make reasonable progress. By referencing and including LADCO's 2021 TSD as appendix B to its 2024 SIP submission, Illinois EPA also documented the Memorandum of Agreements between the Region 5 States and LADCO as well as the agreement from the States to use the analysis process provided by LADCO for regional haze efforts.

In addition to including LADCO's 2021 TSD as appendix B to its 2024 SIP submission, Illinois EPA described the technical analyses performed by LADCO and the EPA that the State relied upon for modeling visibility impacts of Illinois sources on Class I areas and projecting 2028 visibility conditions.

The cost and engineering analyses performed by Illinois EPA to address the four statutory factors were summarized in section V of the State's SIP submission and described in detail in appendix A to the submission.

Throughout its 2024 SIP submission, Illinois provided 2016 emissions data and other information used by LADCO to calculate Q/d values and project 2028 visibility conditions. Illinois EPA explained that because LADCO's Q/d analysis was performed in 2017, the 2016 emissions data used for the analysis was the best and most recent data available at the time. Also, as mentioned above, Illinois EPA reasoned that there have been no emissions increases large enough to make use of the 2016 data inappropriate. Illinois EPA also provided Clean Air Markets Program Data (CAMPD)  47 from 2018 to 2022 that it had considered as well as the 2014, 2017, and 2020 NEI that it had submitted to the EPA to comply with the triennial reporting requirements of 40 CFR 51 subpart A.

As documented in Illinois' 2024 SIP submission, LADCO's analyses included the collection and analysis of ambient monitoring data, including the IMPROVE monitoring data. In section XII of its 2024 SIP submission, Illinois EPA described its monitoring network, which it uses to measure the ambient concentrations of pollutants including those that contribute to visibility degradation. Illinois also included its annual 2023 Ambient Air Monitoring Network Plan as appendix E to its 2024 SIP submission and committed to maintaining its monitoring network in section I of its 2024 SIP submission.

The EPA proposes to find that Illinois' documentation of the technical basis of the long-term strategy, including the modeling, monitoring, engineering, cost, and emissions information discussed above, satisfies the requirements of 40 CFR 51.308(f)(2)(iii).

The provisions of 51.308(f)(2)(iii) require that the emissions information considered to determine the measures that are necessary to make reasonable progress include information on emissions for the most recent year for which the State has submitted triennial emissions data to the EPA (or a more recent year), with a 12-month exemption period for newly submitted data. The most recent triennial NEI at the time of Illinois' SIP submission was 2020. Illinois EPA's regional haze SIP revision for the second implementation period included NEI data for 2014, 2017, and 2020. For its four-factor analyses and demonstrations of existing effective controls, Illinois EPA used 2015 to 2022 emissions data where applicable, including 2018—2022 data from CAMPD and 2028 projections from LADCO and ERTAC. Based on Illinois EPA's consideration and analysis of the emissions information to determine measures necessary for reasonable progress, including the most recent NEI available at the time and emissions data from other sources and years, the EPA proposes to find that Illinois has satisfied the emissions information requirement in 40 CFR 51.308(f)(2)(iii).

In addition to the four statutory factors, section 169A(b)(2)(B) of the CAA requires the EPA to ensure that each SIP contains a long-term (ten to fifteen year) strategy for making reasonable progress toward meeting the national goal of addressing impairment of visibility in mandatory Class I Federal areas from manmade air pollution. Accordingly, the EPA established five additional factors listed in 40 CFR 51.308(f)(2)(iv) that States must consider in developing their long-term strategies. In section VIII of Illinois' 2024 SIP submission, Illinois EPA explained how it had addressed this requirement. For the reasons discussed below, the EPA proposes to find that Illinois adequately considered the five additional factors in developing its 2024 SIP submission.

As required by 40 CFR 51.308(f)(2)(iv)(A), Illinois considered emission reductions due to ongoing air pollution control programs. These include State and Federal regulations reducing emissions from point sources, on-road and non-road mobile sources, and area sources. Illinois EPA listed over 30 standards and programs that have been—and are expected to continue—limiting haze-forming emissions in Illinois.

Pursuant to 40 CFR 51.308(f)(2)(iv)(B), Illinois EPA considered measures to mitigate the impacts of construction activities on visibility in Class I areas. Illinois EPA noted that construction activities in Illinois are unlikely to contribute significantly to visibility impairment at Class I areas due to their distance from the State. Illinois EPA also explained that in addition to Federal non-road standards for construction vehicles and equipment, construction projects in Illinois are often subject to contract restrictions, including idling restrictions for construction vehicles and equipment; the EPA-approved controls for non-road diesel equipment; use of newer, cleaner, and more fuel-efficient engines for equipment; and optimizing earthwork and excavation to minimize haul trips. Illinois EPA noted that the State also requires the use of ultra-low sulfur diesel fuel, 48 which also mitigates the environmental impacts of construction because construction equipment generally uses diesel fuel. Finally, Illinois EPA committed to continue working with other State and Federal agencies to ensure that environmental impacts are given due consideration in construction project contracting.

As required by 40 CFR 51.308(f)(2)(iv)(C), Illinois EPA considered source retirement and replacement schedules in developing its long-term strategy.

In accordance with 40 CFR 51.308(f)(2)(iv)(D), Illinois EPA considered basic smoke management practices for prescribed fire used for agricultural and wildland vegetation management purposes and chose to prepare a statewide voluntary smoke management plan in cooperation with State land managers. The Illinois Smoke Management Plan is included as appendix F to Illinois' 2024 SIP submission and provides strategies for minimizing smoke during prescribed burns, best management practices for burns, and guidance on when to burn based on the Air Quality Index.

As required by 40 CFR 51.308(f)(2)(iv)(E), Illinois EPA considered the anticipated net effect on visibility due to projected changes in point, area, and mobile source emissions over the period addressed by its long-term strategy. This consideration led Illinois to choose to focus on point sources for the second implementation period but to also include measures controlling mobile and area source emissions in its long-term strategy. Illinois included tables in its submission showing 2016 emissions of NO X , PM 2.5 , SO 2 , and VOC from point, area, and mobile sources compared to projected 2028 emissions of the same pollutants by the same source categories.

After considering information regarding existing effective controls, the four statutory factors in 40 CFR 51.308(f)(2)(i), the five additional factors in 40 CFR 51.308(f)(2)(iv), and other requirements described above, the EPA proposes to find that Illinois has submitted a regional haze plan that meets the requirements of 40 CFR 51.308(f)(2) related to development of a long-term strategy. Thus, the EPA proposes to find that Illinois has satisfied the applicable requirements for making progress towards natural visibility conditions in Class I areas that may be affected by emissions from the State.

Section 51.308(f)(3) contains the requirements pertaining to RPGs for each Class I area. Section 51.308(f)(3)(i) requires a State in which a Class I area is located to establish RPGs—one each for the most impaired and clearest days—reflecting the visibility conditions that will be achieved at the end of the implementation period as a result of the emission limitations, compliance schedules and other measures required under paragraph (f)(2) to be in States' long-term strategies, as well as implementation of other CAA requirements. The long-term strategies as reflected by the RPGs must provide for an improvement in visibility on the most impaired days relative to the baseline period and ensure no degradation on the clearest days relative to the baseline period. Section 51.308(f)(3)(ii) applies in circumstances in which a Class I area's RPG for the most impaired days represents a slower rate of visibility improvement than the uniform rate of progress calculated under 40 CFR 51.308(f)(1)(vi). Under 40 CFR 51.308(f)(3)(ii)(A), if the State in which a mandatory Class I area is located establishes an RPG for the most impaired days that provides for a slower rate of visibility improvement than the URP, the State must demonstrate that there are no additional emission reduction measures for anthropogenic sources or groups of sources in the State that would be reasonable to include in its long-term strategy. Section 51.308(f)(3)(ii)(B) requires that if a State contains sources that are reasonably anticipated to contribute to visibility impairment in a Class I area in another State, and the RPG for the most impaired days in that Class I area is above the URP, the upwind State must provide the same demonstration.

Because Illinois has no Class I areas within its borders to which the requirements of the visibility protection program apply in 40 CFR part 81, subpart D, Illinois is subject to 40 CFR 51.308(f)(3)(ii)(B), but not 40 CFR 51.308(f)(3)(i) or (f)(3)(ii)(A).

Under 40 CFR 51.308(f)(3)(ii)(B), a State that contains sources that are reasonably anticipated to contribute to visibility impairment in a Class I area in another State for which a demonstration by the other State is required under 40 CFR 51.308(f)(3)(ii)(B) must demonstrate that there are no additional emission reduction measures that would be reasonable to include in its long-term strategy. Table 3.1 of Illinois' 2024 SIP submission shows that at each of the Class I areas impacted by emissions from Illinois, the 2028 projected visibility impairment is not above the adjusted URP glidepaths for the 20 percent most impaired days. Because no Class I areas impacted by emissions from Illinois have RPGs above the 2028 URP, Illinois is not required to demonstrate that there are no additional emission reduction measures for anthropogenic sources or groups of sources that would be reasonable to include in their long-term strategies. Therefore, the EPA proposes that the demonstration requirement under 40 CFR 51.308(f)(3)(ii)(B) does not apply to Illinois.

The EPA proposes to determine that Illinois has satisfied the applicable requirements of 40 CFR 51.308(f)(3) relating to RPGs.

Section 51.308(f)(6) specifies that each comprehensive revision of a State's regional haze SIP must contain or provide for certain elements, including monitoring strategies, emissions inventories, and any reporting, recordkeeping and other measures needed to assess and report on visibility. A main requirement of this section is for States with Class I areas to submit monitoring strategies for measuring, characterizing, and reporting on visibility impairment. Compliance with this requirement may be met through participation in the IMPROVE network.

Section 51.308(f)(6)(i) requires SIPs to provide for the establishment of any additional monitoring sites or equipment needed to assess whether reasonable progress goals to address regional haze for all mandatory Class I Federal areas within the State are being achieved. Section 51.308(f)(6)(ii) requires SIPs to provide for procedures by which monitoring data and other information are used in determining the contribution of emissions from within the State to regional haze visibility impairment at mandatory Class I Federal areas both within and outside the State. All provisions under 40 CFR 51.308(f)(6) apply only to States containing mandatory Class I Federal areas listed in 40 CFR part 81, subpart D. As noted above, Illinois does not have any mandatory Class I Federal areas located within its borders to which the requirements of the visibility protection program apply in 40 CFR part 81, subpart D. Therefore, 40 CFR 51.308(f)(6)(i) and (ii) do not apply.

The provisions of 40 CFR 51.308(f)(6)(iii) require States with no Class I areas to include procedures by which monitoring data and other information are used in determining the contribution of emissions from within the State to regional haze visibility impairment at Class I areas in other States. States with Class I areas must establish a monitoring program and report data to the EPA that is representative of visibility at the Class I Federal areas. The IMPROVE network meets this requirement. Illinois EPA does not have any Class I areas or operate any monitoring sites under the Federal IMPROVE program. Therefore, the RHR does not require the approval of Illinois' monitoring network. However, Illinois EPA did include a description and a map of its monitoring network in its 2024 SIP revision and attached the Illinois Ambient Air Monitoring 2023 Network Plan as appendix E to the submission. Illinois EPA explained that the procedures by which monitoring data and other information are used to determine the contribution of Illinois emissions to visibility impairment at all affected Class I areas were established in conjunction with LADCO. Sections 7.0 and 8.0 of LADCO's TSD—included as appendix B to Illinois' 2024 SIP revision—describe the procedures.

Section 51.308(f)(6)(iv) requires the SIP to provide for the reporting of all visibility monitoring data to the Administrator at least annually for each Class I area in the State. As noted above, Illinois does not have any mandatory Class I Federal areas located within its borders to which the requirements of the visibility protection program apply in 40 CFR part 81, subpart D. Therefore, 40 CFR 51.308(f)(6)(iv) does not apply.

Section 51.308(f)(6)(v) requires SIPs to provide for a statewide inventory of emissions of pollutants that are reasonably anticipated to cause or contribute to visibility impairment, including emissions for the most recent year for which data are available and estimates of future projected emissions. It also requires a commitment to update the inventory periodically. Illinois' 2024 SIP submission provided statewide inventories of such emissions and future 2028 projected emissions in Tables 3.2, 3.3, 11.5, 11.6, and 11.7, including emissions information from the 2014, 2017, and 2020 NEI. Additionally, Illinois EPA provided CAMPD information for 2018 to 2022 and historical EGU emissions information from 1999 to 2020 in Figures 3.5 and 3.6. For future projected emissions, Illinois EPA relied on LADCO's analysis, which estimated 2028 projected emissions of SO 2 and NO X for specific facilities in the LADCO States based on 2016 emissions as well as ERTAC and State forecasts. These projected emissions were included in Illinois' 2024 SIP submission as well as in LADCO's TSD, which Illinois EPA included as appendix B to its 2024 SIP submission. In its 2024 SIP submission, Illinois EPA committed to continue updating its emissions inventory  49 and to continue working with LADCO to project future emissions of relevant pollutants. The EPA proposes to find that Illinois has met the requirements of 40 CFR 51.308(f)(6).

Section 51.308(f)(5) requires that periodic comprehensive revisions of States' regional haze plans also address the progress report requirements of 40 CFR 51.308(g)(1) through (5). The purpose of these requirements is to evaluate progress towards the applicable RPGs for each Class I area within the State and each Class I area outside the State that may be affected by emissions from within that State. Sections 51.308(g)(1) and (2) apply to all States and require a description of the status of implementation of all measures included in a State's first implementation period regional haze plan and a summary of the emission reductions achieved through implementation of those measures. Section 51.308(g)(3) applies only to States with Class I areas within their borders and requires such States to assess current visibility conditions, changes in visibility relative to baseline (2000-2004) visibility conditions, and changes in visibility conditions relative to the period addressed in the first implementation period progress report. Section 51.308(g)(4) applies to all States and requires an analysis tracking changes in emissions of pollutants contributing to visibility impairment from all sources and sectors since the period addressed by the first implementation period progress report. This provision further specifies the year or years through which the analysis must extend depending on the type of source and the platform through which its emission information is reported. Finally, 40 CFR 51.308(g)(5), which also applies to all States, requires an assessment of any significant changes in anthropogenic emissions within or outside the State have occurred since the period addressed by the first implementation period progress report, including whether such changes were anticipated and whether they have limited or impeded expected progress towards reducing emissions and improving visibility.

Prior to its 2024 SIP submission, Illinois submitted its first 5-year progress report to the EPA on February 2, 2017, and the EPA approved it on April 3, 2018. 83 FR 15744, April 12, 2018. Thus, the progress report elements included in section XI of Illinois' SIP revision for the second implementation period addressed 2017 through 2021. This is consistent with 40 CFR 51.308(f)(5), which requires States to address the elements in 40 CFR 51.308(g)(1) through (5) for the period since the most recent progress report.

As required by 40 CFR 51.308(g)(1), Illinois EPA described the implementation status of the measures relied on for reasonable progress in the first implementation period in section XI of its submission. These included NO X and SO 2 emission limits in source-specific permits for two EGUs—the City of Springfield's City Water, Light & Power facility in Dallman and Kincaid Generation, LLC; consent decrees mandating BART for two petroleum refineries—CITGO Petroleum Corporation and ExxonMobil Oil Corporation; and emission reductions at all EGUs subject to the MPS and CPS.

Pursuant to 40 CFR 51.308(g)(2), Illinois EPA summarized the emission reductions achieved through the implementation of these measures in Tables 4.4 through 4.7 and 11.1 through 11.4 of its submission. Illinois EPA also reproduced the list of on-the-books control strategies that had been included in its 2017 progress report and provided the status of these measures.

The provisions of 40 CFR 51.308(g)(3) require States to assess Reasonable Progress Goals, including current visibility conditions and changes, for any Class I areas within the State. Because Illinois has no Class I areas, the requirements of 40 CFR 51.308(g)(3) do not apply to Illinois.

Pursuant to 40 CFR 51.308(g)(4), Tables 11.5 to 11.7 of Illinois EPA's 2024 SIP submission tracked changes in emissions of CO, NH 3 , NO X , PM 10 , PM 2.5 , SO 2 , and VOCs from 2014 through 2020. Changes in NO X and SO 2 emissions from all Illinois EGUs from 1999 through 2020 were also provided in Figures 3.5 and 3.6 of the 2024 SIP submission and changes in NO X and SO 2 emissions from specific sources from 2018 through 2022 were provided in section VI of the 2024 SIP submission.

Addressing 40 CFR 51.308(g)(5), Illinois EPA did not identify any significant changes in anthropogenic emissions within the State that have occurred since its 2011 regional haze SIP submission that could limit or impede visibility progress. Illinois EPA reported that all projected emission reductions anticipated in the 2011 regional haze SIP submission and in the 2017 progress report have been realized.

The EPA proposes to find that Illinois EPA has met the requirements of 40 CFR 51.308(g)(1) through (5).

CAA section 169A(d) requires States to consult with FLMs before holding the public hearing on a proposed regional haze SIP, and to include a summary of the FLMs' conclusions and recommendations in the notice to the public. In addition, 40 CFR 51.308(i)(2)'s FLM consultation provision requires a State to provide FLMs with an opportunity for consultation that is early enough in the State's policy analyses of its emission reduction obligation so that information and recommendations provided by the FLMs' can meaningfully inform the State's decisions on its long-term strategy. If the consultation has taken place at least 120 days before a public hearing or public comment period, the opportunity for consultation will be deemed early enough. Regardless, the opportunity for consultation must be provided at least sixty days before a public hearing or public comment period at the State level. Section 51.308(i)(2) also provides two substantive topics on which FLMs must be provided an opportunity to discuss with States: assessment of visibility impairment in any Class I area and recommendations on the development and implementation of strategies to address visibility impairment. Section 51.308(i)(3) requires States, in developing their implementation plans, to include a description of how they addressed FLMs' comments.

Illinois engaged with FLMs at multiple points in the development process of its SIP revision, including NPS, USFS, FWS, and the U.S. Department of Interior—Bureau of Land Management. On March 9, 2020, NPS emailed Illinois a list of sources recommended for four-factor analysis. Illinois EPA shared a draft SIP revision with NPS and USFS on August 14, 2023, thus beginning the formal FLM consultation process over 120 days before posting the proposed SIP submission for public comment. On October 4, 2023, Illinois EPA attended a consultation call with NPS and USFS during which the FLMs summarized their conclusions and recommendations for the draft SIP revision. On October 13, 2023, Illinois received letters from NPS and USFS describing their recommendations in technical detail. As required by 40 CFR 51.308(i)(3) and noted in the EPA's November 12, 2025, TSD, Illinois summarized the FLMs' initial recommendations in section XIII of its SIP submission and included summaries of the FLMs' comments with a response to each, as well as the full letters received from the FLMs, in appendix H of its submission.

Illinois published a public notice of its proposed SIP revision on Illinois EPA's website  50 on January 19, 2024, beginning a 30-day public comment period and stating that a public hearing would be held if requested. In accordance with 40 CFR 51.308(i)(2), Illinois began the public comment period at least 60 days after initiating the FLM consultation process and, as required by CAA section 169A(d), included summaries of the FLMs' recommendations in the public notice. On January 23, 2024, Illinois received requests for a hearing and an extension of the public comment period. On January 26, 2024, Illinois published a public notice of a virtual hearing to be held on February 27, 2024, and of a 30-day extension of the comment period. The hearing was held as planned on February 27, 2024. In total, Illinois received four written comments and one oral comment during the 60-day public comment period and concurrent hearing. Illinois included the public comments and Illinois' responses in attachments 3 and 4 to its submission, including a letter from NPS addressing Illinois' responses to NPS' initial recommendations for the SIP revision.

The provisions of 40 CFR 51.308(i)(4) require States to provide procedures for continuing consultation with FLMs on the implementation of visibility protection program requirements. As an active member of LADCO, Illinois continues to coordinate regularly with FLMs on the implementation of visibility protection plans and the planning of future work. In its 2024 SIP submission, Illinois committed to continue its fulfillment of all requirements of 40 CFR 51.308, including maintenance of adequate monitoring networks and production of emissions inventories, progress reports, and future SIP revisions. Given Illinois' actions recounted above, the EPA proposes to find that Illinois has satisfied the requirements of both 40 CFR 51.308(i) and 169A(d) to consult with the FLMs on its regional haze SIP for the second implementation period.

Whenever the EPA promulgates a new or revised NAAQS, CAA section 110(a)(1) requires States to make SIP submissions to provide for the implementation, maintenance, and enforcement of the NAAQS. This particular type of SIP submission is commonly referred to as an “infrastructure SIP.” These submissions must meet the various requirements of CAA section 110(a)(2), as applicable. Due to ambiguity in some of the language of CAA section 110(a)(2), the EPA believes that it is appropriate to interpret these provisions in the specific context of acting on infrastructure SIP submissions. The EPA has previously provided comprehensive guidance on the application of these provisions through a guidance document for infrastructure SIP submissions (EPA's 2013 Guidance) and through regional actions on infrastructure submissions. 51 Unless otherwise noted below, we are following that existing approach in acting on this submission. In addition, in the context of acting on such infrastructure submissions, the EPA evaluates the submitting State's SIP for facial compliance with statutory and regulatory requirements, not for the State's implementation of its SIP. 52 The EPA has other authority to address any issues concerning a State's implementation of the rules, regulations, consent orders, etc. that comprise its SIP.

CAA section 110(a)(2)(D)(i)(II) prohibits emissions in one State from interfering with visibility protection measures in another State. On September 29, 2017, and May 16, 2019, Illinois submitted SIP revisions addressing infrastructure requirements for the 2012 PM 2.5 and 2015 ozone NAAQS, respectively.

This proposed rulemaking evaluates the element of Illinois EPA's SIP submissions for the 2012 PM 2.5 and 2015 ozone NAAQS addressing the fourth component (“Prong 4”) of CAA section 110(a)(2)(D)(i)—the requirement that a State's SIP contain adequate provisions prohibiting any source or other type of emissions activity within the State from emitting any air pollutant in amounts which will interfere with measures required to be included in the applicable SIP for any other State to protect visibility.

Under the applicable requirements for visibility protection of CAA section 110(a)(2)(D)(i)(II), States are subject to visibility and regional haze program requirements under part C of the CAA, which includes sections 169A and 169B. The EPA's 2013 Guidance states that these Prong 4 requirements can be satisfied by approved SIP provisions that the EPA has found to adequately address any contribution of that State's sources that impact the visibility program requirements in other States. 53 The EPA's 2013 Guidance lays out how a State's infrastructure SIP may satisfy Prong 4. In the second implementation period, confirmation that the State has a fully approved regional haze SIP that fully meets the requirements of 40 CFR 51.308 will satisfy the requirements of Prong 4. 54

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

To address the requirements of CAA section 110(a)(2)(D)(i)(II), both Illinois EPA's September 29, 2017, infrastructure SIP submission for the 2012 PM 2.5 NAAQS and Illinois EPA's May 16, 2019, submission for the 2015 ozone NAAQS discuss the State's Prevention of Significant Deterioration program, nonattainment New Source Review program, and regional haze program. As discussed in the “Background on Illinois' First Implementation Period SIP Submission” section of this proposed rulemaking and noted in Illinois EPA's submissions, Illinois' regional haze SIP for the first implementation period was approved on July 6, 2012 (77 FR 39943), effective August 6, 2012.

In this proposed rulemaking, the EPA is proposing to approve Illinois' regional haze plan for the second implementation period. For the reasons stated above, by meeting the statutory and regulatory requirements of the regional haze program, including the interstate consultation requirements in 40 CFR 51.308(f)(2)(ii), Illinois' SIP adequately prohibits emissions from within the State that would interfere with visibility protection measures in any other State's SIP. Therefore, the EPA proposes that Illinois has met the applicable section 110(a)(2)(D)(i)(II) Prong 4 requirement relating to visibility protection for the 2012 PM 2.5 and 2015 ozone NAAQS.

The EPA proposes to approve Illinois' SIP submission, dated June 3, 2024, as satisfying the regional haze requirements for the second implementation period contained in 40 CFR 51.308(f). The EPA also proposes to approve Illinois' SIP submissions, dated September 29, 2017, and May 16, 2019, as satisfying the interstate transport infrastructure requirements related to visibility protection contained in CAA section 110(a)(2)(D)(i)(II) for the 2012 PM 2.5 and 2015 ozone NAAQS.

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

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

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

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

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

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

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

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

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

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

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

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

Michigan's Part 6 rules regulate existing sources of VOC emissions, while Michigan's Part 8 rules regulate existing sources of NO X emissions. The EPA is proposing to approve various revisions and additions to MAPCR Parts 6 and 8, except for MAPCR Rule 336.1601(a), which Michigan requested that the EPA not incorporate into the SIP. The EPA is also proposing to remove the current SIP approved version of R 336.1632, except for subrule (15), and is proposing to approve Michigan's updated version of R 336.1632 (effective April 18, 2023), except for subrule (9), which Michigan requested the EPA not incorporate into the SIP. Michigan submitted these SIP revisions to meet the Moderate VOC and NO X RACT requirements for the Western Michigan nonattainment areas under the 2015 ozone standard.

The EPA is proposing to approve MAPCR Rules 336.1660 and 336.1662, which limit VOC emissions from consumer products and architectural and industrial maintenance coatings, as SIP strengthening measures for the areas. Although Michigan requested SIP revisions to Rules 336.1841(8), 336.1842(10), and 336.1844(9), the EPA is not proposing action on these revisions in this action.

Finally, Michigan did not request EPA action on R. 336.1801, 336.1802, 336.1803, 336.1810, and 336.1818, which are responsive to different CAA requirements and will be considered in a separate rulemaking.

EGLE submitted the VOC SIP revisions on March 7, 2024, supplementing them on May 2, 2024, and submitted the NO X SIP revisions on May 5, 2025, supplementing them on August 6, 2025.

Under Clean Air Act (CAA) section 109, the EPA has established primary and secondary NAAQS for certain air pollutants (referred to as “criteria pollutants”) and conducts periodic reviews of the NAAQS to determine whether they should be revised or whether new NAAQS should be established. The primary NAAQS represent ambient air quality standards which the EPA has determined are necessary to protect the public health with an adequate margin of safety. The secondary NAAQS represent ambient air quality standards which the EPA has determined are necessary to protect the public welfare from any known or anticipated adverse effects associated with the presence of such air pollutant in the ambient air. One such criteria pollutant is ground-level ozone.

Ozone forms from complex chemical reactions in ambient air between NO X and VOCs. Cars, trucks, buses, engines, industries, power plants, and products such as solvents and paints are among the major manmade sources of ozone-forming emissions. Exposure to ozone can harm the respiratory system, aggravate asthma and other lung diseases, and is linked to premature death from respiratory causes.

On October 26, 2015, the EPA promulgated a new 8-hour primary ozone NAAQS of 70 parts per billion (ppb) at 40 CFR 50.19, which is met at an ambient air quality monitoring site when the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentration is less than or equal to 0.070 ppm, as determined in accordance with appendix U of 40 CFR part 50. 1 Upon promulgation of a new or revised NAAQS, the EPA is required to designate all areas of the country as either “attainment” (meets the standard), “nonattainment” (does not meet the standard), or “unclassifiable” (any area that cannot be classified on the basis of available information). 2

Under the cooperative federalism framework of CAA section 110, States and the EPA each play a unique role in ensuring attainment and maintenance of the NAAQS. States are primarily responsible for developing plans for attaining and maintaining the NAAQS in areas within their jurisdiction, based on CAA requirements, planning rules, and guidance promulgated by the EPA. These planning requirements include (but are not limited to) provisions for implementing emissions controls, tracking progress toward attainment and monitoring and reporting air quality data, with the overarching goal of attaining and maintaining the NAAQS as expeditiously as practical, but no later than the CAA's maximum attainment date.

Effective on August 3, 2018, the EPA initially designated 51 areas throughout the country as nonattainment for the 2015 ozone NAAQS, including the Western Michigan nonattainment areas. 3 In a separate action, the EPA assigned classification thresholds based on the severity of an area's ozone levels, determined by the area's monitored design value (DV). 4 As a result of that action, the Western Michigan nonattainment areas were initially classified as Marginal. Also in that action, the EPA established the attainment dates for Marginal, Moderate, Serious, Severe, and Extreme nonattainment areas as 3 years, 6 years, 9 years, 15 years, and 20 years, respectively, from the effective date of the final designations. 5 Therefore, the attainment dates for each nonattainment area classification for the 2015 ozone NAAQS were/are as follows: August 3, 2021, for Marginal areas, August 3, 2024, for Moderate areas, August 3, 2027, for Serious areas, August 3, 2033, for Severe areas, and August 3, 2038, for Extreme areas.

The EPA also promulgated a rulemaking clarifying the CAA's ozone nonattainment area implementation requirements for the 2015 ozone NAAQS (herein referred to as the “2015 Ozone SIP Requirements Rule”). 6 That implementation rulemaking articulated the CAA's substantive requirements for ozone nonattainment areas for each classification level and established deadlines for submission of plan revisions to address those requirements. 7

Effective November 7, 2022, the EPA determined that the Western Michigan nonattainment areas failed to attain by the Marginal area attainment date and the areas were reclassified by operation of law to Moderate. 8 Effective January 16, 2025, the EPA determined that the Western Michigan nonattainment areas failed to attain by the Moderate area attainment date and the areas were reclassified to Serious by operation of law. 9 Michigan's Serious RACT SIP was due on January 1, 2026, but this action addresses RACT for Moderate nonattainment only. 10

RACT is an important strategy for reducing NO X and VOC emissions from major stationary sources and sources covered by a control techniques guideline (CTG) document. Since the 1970s, the EPA has defined RACT as the lowest emission limit that a particular source is capable of meeting by the application of the control technology that is reasonably available considering technological and economic feasibility. 11

Areas designated nonattainment for an ozone NAAQS are subject to the general nonattainment area planning requirements of CAA section 172. Section 172(c)(1) of the CAA provides that SIPs for nonattainment areas must include reasonably available control measures (RACM), including emissions reductions from existing sources through the adoption of RACT. Further, section 182(b)(2) of the CAA sets forth three specific RACT requirements for ozone nonattainment areas classified as Moderate or higher.

First, section 182(b)(2)(A) requires that States submit a revision to their SIP requiring implementation of RACT for each category of VOC sources in the nonattainment area covered by a CTG document issued by the EPA between November 15, 1990, and the date of attainment. Second, section 182(b)(2)(B) requires a SIP revision to implement RACT for all VOC sources in the nonattainment area covered by any CTG issued before November 15, 1990. Third, section 182(b)(2)(C) requires a SIP revision implementing RACT for any other major stationary source of VOCs located in the nonattainment area. This RACT requirement is extended to major stationary sources of NO X in section 182(f) of the CAA, which subjects major stationary sources of NO X to the same requirements that are applicable to major stationary sources of VOCs. These ozone RACT requirements are sometimes referred to collectively as VOC CTG RACT, non-CTG major source VOC RACT, and major source NO X RACT.

A “major source” is defined based on the source's potential to emit (PTE) of NO X , VOC, or both pollutants, and the applicable thresholds differ based on the classification of the nonattainment area in which the source is located. 12

The EPA has affirmed RACT requirements through implementation rules for each ozone NAAQS as well as through guidance. The EPA's 2015 Ozone SIP Requirements Rule outlined the requirements that States with ozone nonattainment areas need to address for the 2015 ozone NAAQS, which include RACT requirements. 13

The preamble to the 2015 ozone implementation rule, consistent with the EPA's prior guidance, says that when determining what is RACT for a particular source or category of sources, air agencies should consider all relevant information (including recent technical information and information received during the State's public comment period) that is available at the time they develop their RACT SIPs. 14 The EPA informally refers to this assessment process as a “due diligence review” and considers it a necessary component of approvable RACT determinations. 15

Further, an air agency that has previously implemented RACT via the EPA-approved SIP revisions for a prior ozone NAAQS may conclude that new or revised RACT regulations are not necessary to meet RACT requirements for a revised ozone NAAQS. In such situations, an air agency may submit SIP revisions certifying that existing RACT regulations are adequate to meet applicable nonattainment area or Ozone Transport Region RACT requirements for a revised ozone NAAQS (these are referred to as “certification SIPs”). States should include an accompanying due diligence analysis in their SIP submittal showing why no new or revised RACT regulations are necessary. Put another way, the SIP submission should include analyses to explain why the previously approved RACT regulations continue to represent RACT for the revised NAAQS. Additionally, if there are no sources covered by a certain CTG within a nonattainment area, a State may submit a negative declaration stating so, in place of regulatory requirements to apply RACT for that category of sources.

This action addresses Michigan's Moderate VOC and NO X RACT SIP submittal for the 2015 ozone standard for the Western Michigan nonattainment areas. This action also addresses rules that reduce VOC emissions from the consumer products and architectural coatings categories.

The EPA previously determined that Michigan's Administrative Code, “Part 6. Emission Limitations and Prohibitions—Existing Sources of Volatile Organic Compound Emissions” met CTG and non-CTG VOC RACT requirements associated with past ozone NAAQS and approved them into the Michigan SIP. These Part 6 VOC regulations were originally developed and incorporated into Michigan's SIP under the previous 1-hour (1979) ozone standard. 16 The Muskegon and Berrien nonattainment areas were redesignated to attainment under the 1997 ozone standard before RACT became due. 17 Michigan was designated attainment/unclassifiable under the 2008 ozone standard, so the State was not required to implement RACT under this standard. 18

To meet the VOC RACT requirements for the 2015 ozone NAAQS, Michigan revised several existing VOC RACT rules in Part 6. These amendments address cases where certain CTGs have been revised or reissued since the State rules were last SIP-approved, and revise certain rules' applicability to include the current ozone nonattainment areas. The amended rules include:

Michigan also adopted new VOC RACT rules in Part 6 for the Western Michigan nonattainment areas under the 2015 ozone standard. These new rules address CTGs the EPA issued since the Part 6 rules were last approved:

In addition, Michigan amended R 336.1601 and R 336.1602 to align with its new and revised CTG-based RACT rules. R 336.1601 establishes definitions for various words and phrases used throughout Part 6 as well as the definition for “existing source.” The EPA is proposing to approve R 336.1601, with the exception of subrule (a), which Michigan requested that the EPA not incorporate into the SIP. R 336.1602, discussed further below, establishes alternative procedures requiring State and EPA SIP approval, as well as requirements for non-CTG RACT analyses.

As noted above, R 336.1632 was revised to address CTGs the EPA issued since the rule was last approved. The EPA is proposing to remove the current SIP-approved version of R 336.1632 from the SIP, with the exception of subrule (15), and is proposing to approve Michigan's current version of R 336.1632, effective April 18, 2023, with the exception of subrule (9), which Michigan requested that the EPA not incorporate into the SIP.

Michigan and the EPA performed RACT due diligence analyses comparing the State's VOC RACT rules to relevant CTGs and RACT rules in other States. The EPA found Michigan's rules to be mostly consistent with similar VOC RACT rules adopted by other States and with the relevant CTGs. The EPA has not identified any new reasonably available control technologies, considering technological and economic feasibility for these sources. As a result of the EPA's due diligence analysis, the EPA is proposing to determine that these VOC RACT regulations are representative of RACT for the Western Michigan nonattainment areas for purposes of the 2015 ozone standard. See more about the due diligence process in the EPA's technical support document (TSD)  19 and in part G of section III of this preamble.

Michigan adopted Rules R 336.1610a, R 336.1620a, R 336.1621a, and R 336.1624a as VOC rules covering CTG categories in nonattainment areas under the 2015 ozone standard.

These rules meet RACT requirements and use the more stringent VOC coating-usage exemption level of 15 pounds per day (lbs/day).

Michigan previously adopted Rules R 336.1610, R 336.1620, R 336.1621, and R 336.1624, which also regulate VOC content in coatings and printing inks. These rules apply to areas not required to comply with rules R 336.1610a, R 336.1620a, R 336.1621a, and R 336.1624a. Michigan finalized Rule 610 in 1980 and Rules 620, 621, and 624 in 1981.

In 1993, Michigan revised these rules to meet the EPA's RACT “fix-up requirement” under CAA section 182(a)(2)(A), which standardized VOC control levels nationwide. The revisions reduced the exemption levels from 2,000 pounds per month (lbs/month) to 15 lbs/day (2.7 tons per year (tpy)). These lower exemptions created significant financial burdens for small coating operations that emitted minimal VOCs. In 1997, Michigan responded by restoring the pre-1993 exemption levels at the State level, which was typically 2,000 lbs/month (12 tpy). The State later made additional revisions to update adoption-by-reference materials and clarify rule language.

Michigan conducted a demonstration for Rules R 336.1610, R 336.1620, R 336.1621, and R 336.1624 to determine whether revising the SIP-approved 15 lbs/day exemption back to 2,000 lbs/month would increase VOC emissions. The analysis evaluated potential changes in emissions by comparing current reported emissions (under the 12 tpy exemption) with projected emissions under the 2.7 tpy exemption. It focused on units with combined emissions between 2.7 and 12 tpy, which are assumed not to be subject to the current SIP-approved rules.

Michigan's analysis shows that the higher exemption limits will not increase emissions. In fact, actual emissions under the higher exemption limit (12 tpy or 2,000 lbs/month) were lower than the potential emissions allowed under the stricter 15 lbs/day exemption limit.

Therefore, the EPA is proposing to approve Rules R 336.1610, R 336.1620, R 336.1621, and R 336.1624 into the Michigan SIP as satisfying CAA section 110(l) requirements, because the revisions will not interfere with attainment or reasonable further progress.

For the Western Michigan nonattainment areas, Michigan provided Negative Declarations for the following CTGs: “Manufacture of Pneumatic Rubber Tires,” “Large Petroleum Dry Cleaners,” “Manufacture of High-Density Polyethylene, Polypropylene, and Polystyrene Resins,” “Air Oxidation Processes in Synthetic Organic Chemical Manufacturing Industry,” “Reactor Processes and Distillation Operations in Synthetic Organic Chemical Manufacturing Industry,” “Shipbuilding and Ship Repair Operations,” “Large Appliance Coatings,” and “Oil and Natural Gas Industry.” Michigan reviewed facilities in the Western Michigan nonattainment areas for the 2015 ozone standard and determined that no sources are subject to any of these CTGs. To reach this conclusion, Michigan used its Michigan Air Emissions Reporting System (MAERS), Michigan Air Compliance Emissions System (MACES), district office outreach, and external stakeholder workgroup feedback. The EPA concurs with Michigan that there are no applicable sources for the RACT categories covered by these negative declarations.

In Moderate ozone nonattainment areas, non-CTG VOC major sources, which are subject to RACT, are stationary sources with a PTE of 100 tpy or more of VOCs. Many major VOC sources located in the Western Michigan ozone nonattainment areas are subject to categorical RACT rules. Michigan's VOC RACT rules currently establish non-CTG RACT for two source categories. Michigan revised these rules, extending their geographic applicability to include the Western Michigan 2015 ozone nonattainment areas:

Michigan's due diligence analysis, available in the docket, compares its non-CTG categorical RACT rules to similar rules adopted by other States. The EPA found Michigan's rules to be consistent with those comparisons and did not identify any new control technologies that are reasonably available considering technological and economic feasibility for these sources. As a result of Michigan's due diligence analysis, the EPA is proposing to determine that these non-CTG VOC RACT regulations are still representative of RACT for the Western Michigan nonattainment areas under the 2015 ozone standard. See more about the due diligence process in part G of section III of this preamble.

MAPCR Rule 336.1602(4) requires non-CTG VOC major sources that are not regulated under other Michigan VOC RACT rules to submit RACT studies within 6 months of final promulgation of Michigan's rule or an alternative timeframe approved by Michigan. Similarly, MAPCR Rule 336.1846 requires NO X major sources that are not covered by other Michigan NO X RACT rules to submit RACT studies within one year of the effective date of Michigan's rule. Michigan will then submit the source-specific RACT plans with enforceable measures to the EPA for review and approval into the Michigan SIP. Since these procedural rules do not establish any control standards, they do not themselves establish RACT-level controls. However, all of the non-CTG VOC and NO X major sources in the Western Michigan nonattainment areas are covered by non-CTG categorical rules and none currently exist that would be subject to Rules 336.1602(4) or 336.1846. The EPA is proposing to approve Rules 336.1602(4) and 336.1846 into Michigan's SIP.

The EPA is proposing to approve Michigan's amended Rule 336.1660 and newly added Rule 336.1662 as SIP strengthening for the Western Michigan nonattainment areas under the 2015 ozone standard. Rule 336.1660 reduces VOC emissions from consumer products, while Rule 336.1662 limits VOC emissions from architectural and industrial maintenance coatings. Neither rule is based on CTGs. Rule 336.1661 is being rescinded, as its content has been incorporated into the updated R 336.1660.

Michigan developed a comparison table evaluating its VOC RACT rules against applicable CTGs and RACT regulations in other States. The EPA performed a due diligence analysis to evaluate Michigan's VOC and NO X RACT submittal and to supplement Michigan's comparison table for the Western Michigan nonattainment areas under the 2015 ozone standard. In the EPA's TSD (available in the docket), the EPA details the basis for concluding that Michigan's regulations fulfill RACT through comparison with RACT rules developed by other States, CTG guidance documents, and applicable Alternative Control Technology (ACT) documents. The EPA evaluated the relevant RACT rules in various States including Region 5 States (Illinois, Ohio, Indiana, and Wisconsin) and States in EPA Regions 1, 2, 6, 8, and 9 (Maine, Vermont, California, Colorado, Texas, Arizona, New Jersey, Connecticut, and New York). The EPA found Michigan's rules to be generally consistent with or more stringent than control measures in other States' regulations, CTGs, and ACT documents. The EPA has not identified any new control technologies that are reasonably available considering technological and economic feasibility for these sources. Based upon our findings, the EPA proposes to determine that Michigan's VOC and NO X rules represent RACT.

“Part 8. Emission Limitations and Prohibitions—Oxides of Nitrogen” has not been previously submitted or approved into Michigan's SIP. Michigan promulgated NO X RACT emission standards for various sizes of engines, boilers, combustion turbines, miscellaneous process-specific combustion sources, and Alternative NO X RACT, which are contained in MAPCR R 336.1840-R336.1845.

Michigan evaluated other States' recent RACT regulations and analyzed emissions and operational profiles of combustion units at major source facilities in Michigan to determine RACT requirements for these categories. These regulations establish NO X RACT requirements for combustion engines, boilers, combustion turbines, hot mix asphalt plants, process heaters, engine test cells, lime kilns, and glass manufacturing. They also outline the process and timeline for proposing alternative RACT for emission units that would otherwise be subject to the Part 8 NO X RACT requirements. The EPA is proposing to approve the following sections of MAPCR Part 8 as meeting the NO X RACT requirement for the Western Michigan nonattainment areas under the 2015 ozone standard into the Michigan SIP: R 336.1840, 336.1841(1)-(7), 336.1842(1)-336.1842(9), 336.1843, 336.1844(1)-336.1844(8), and R336.1845. In the EPA's due diligence analysis, the EPA compares Michigan's NO X RACT rules to other relevant State rules and ACTs. The EPA found Michigan's rules to be in some cases more stringent than other states' NO X RACT rules and consistent with the ACTs. The EPA has not identified any new control technologies that are reasonably available considering technological and economic feasibility for these sources. See the EPA's TSD and this preamble for more information on the EPA's due diligence analysis.

The Consumer Products and AIM Coatings Rules are not RACT rules. However, Michigan submitted these VOC SIP revisions as part of its attainment strategy for the Western Michigan nonattainment areas under the 2015 ozone standard. The EPA is proposing to approve Michigan's Rules R 336.1660 and R 336.1662, which establish VOC limits for consumer products and architectural and industrial maintenance coatings, as SIP-strengthening measures for the Western Michigan nonattainment areas under the 2015 ozone standard. Michigan is relying in part on the VOC emission reductions from these rules to meet the reasonable further progress requirements under CAA section 182(b)(1). Rule 336.1660 regulates VOC emissions reductions from consumer products, while Rule 336.1662 regulates VOC emissions reductions from architectural and industrial maintenance coatings. Neither rule is based on CTGs. Michigan is rescinding Rule 336.1661 because its content is now incorporated into the updated R 336.1660.

The EPA is proposing to approve various revisions and additions to MAPCR Parts 6 and 8 into the Michigan SIP as described in the Preamble above. The EPA is proposing to approve these revisions as meeting the Moderate VOC and NO X RACT requirements of CAA sections 182(b)(2) and NO X RACT requirements of 182(f) of the CAA, respectively, for the Western Michigan nonattainment areas under the 2015 ozone standard. EPA is also proposing to approve MAPCR Rules 336.1660 and 336.1662, which limit VOC emissions from consumer products and architectural and industrial maintenance coatings, as SIP strengthening measures for the areas. The EPA is not acting on R 336.1841(8), R 336.1842(10), and R 336.1844(9), and will address these rules in a separate action.

In this rulemaking, 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 Michigan rules R 336.1601; except for R 336.1601(a);R 336.1602; R 336.1606; R 336.1607; R 336.1608; R 336.1609; R 336.1610; R 336.1610a; R 336.1611; R 336.1618; R 336.1620; R 336.1620a; R 336.1621; R 336.1621a; R 336.1622; R 336.1623; R 336.1624; R 336.1624a; R 336.1625; R 336.1627; R 336.1628; R 336.1629; R 336.1630; R 336.1631; R 336.1632, except for R 336.1632(9); R 336.1633; R 336.1634; R 336.1635; R 336.1636; R 336.1637; R 336.1638; R 336.1639; R 336.1640; R 336.1641; R 336.1642; R 336.1643; R 336.1644; R 336.1660; R 336.1661 (Rescinded); and R 336.1662; effective April 18, 2023, and R 336.1840; R 336.1841,except for R 336.1841(8); R 336.1842, except for R 336.1842(10); R 336.1843; R 336.1844, except for R 336.1844(9); R 336.1845; and R 336.1846; effective April 28, 2025, discussed in section III of this preamble. The EPA has made, and will continue to make, these documents generally available through www.regulations.gov and at the EPA Region 5 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

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

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

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

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

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

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

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

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

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

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

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

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

The EPA is proposing to approve a revision to Indiana's VOC SIP for Keystone. The company has requested that it be permitted to use an oil cover as an equivalent control device for its cold cleaner degreaser, as provided in 326 IAC 8-1-5 and 326 IAC 8-3-2. The oil cover, Aquastrip Fume Seal, is a layer of mineral oil at least one-inch thick floating over the cleaning solvent in a dip tank. The solvent is a mixture of two water miscible compounds, n-Methyl Pyrrolidone (NMP) and monoethanolamine (MEA). The oil cover controls VOC emissions from the dip tank by reducing solvent evaporation.

Indiana's cold cleaner degreaser control requirements are contained in 326 IAC 8-3-2. Under 326 IAC 8-3-2(b)(1), degreasers with solvent that is heated to a temperature of greater than forty-eight and nine-tenths (48.9) degrees Celsius, or 120 degrees Fahrenheit, are required to control VOC emissions using one of the following control devices: a freeboard ratio of 0.75 or greater; a water cover over the solvent when the solvent used is insoluble in, and heavier than, water; a refrigerated chiller; carbon adsorption; or VOC emission control equipment operated in accordance with 326 IAC 8-3-8(b)(3). Per 326 IAC 8-1-5(a), “[a]n owner or operator of a source may submit a petition . . . requesting a site-specific Reasonably Available Control Technology (RACT) plan as an alternative to the requirements in 326 IAC 8.” In accordance with 326 IAC 8-1-5(a)(6), the petition must include, among other things, a demonstration that the alternative control program constitutes RACT for the petitioned facility, and address the factors listed in 326 IAC 8-1-5(a)(6). Such alternative systems, however, must be submitted to and approved by the EPA as a SIP revision as required by 326 IAC 8-1-5(c).

IDEM supplied the EPA with technical information on the solvents used by Keystone and the requested oil cover. IDEM also provided information on why a water cover would not work with the solvents used and why the freeboard ratio of the tank cannot practically be increased to the level required by 326 IAC 8-3-2.

The solvents Keystone uses, NMP and MEA, are miscible in water, and attempts to use a water cover would fail to reduce VOC emissions. The water would blend with the cleaning solvents and not provide any barrier against solvent evaporation. To meet the freeboard ratio requirement of 0.75, Keystone would need to raise the freeboard height on its dip tank to 108 inches (9 feet). This would require that the building be altered to accommodate the dip tank's increased height. The cost of raising the roof or lowering the floor makes this option cost prohibitive. IDEM also addressed why the use of a refrigerated condenser and carbon adsorption system, listed as options in 326 IAC 8-3-2(b), would not be feasible for Keystone due to the capital expenditures required for the installation, operation, and modification to the building, as well as increased worker hazards and environmental impacts from either control system.

In its ”Guide to Cleaner Technologies: Cleaning and Degreasing Process Changes” (EPA/625/R-93/017), the EPA suggests the use of an oil cover for operations using heated NMP. Keystone will use a heated NMP and MEA solvent blend in its operation. The supplied technical information shows that NMP and MEA have similar vapor densities. The oil cover, a layer of mineral oil at least one inch thick, provides a physical barrier between the cleaning solvents and the atmosphere. Thus, it is reasonable to expect an oil cover will provide an equivalent control technique for VOC emissions from an NMP and MEA solvent blend.

This request constitutes a petition for a site-specific RACT plan under 326 IAC 8-1-5. Consequently, Keystone was required to demonstrate to IDEM that the oil cover constitutes RACT for the subject facility, as well as address the other factors specified in 326 IAC 8-1-5(a).

IDEM provided a demonstration of compliance with Clean Air Act (CAA) section 110(l), 42 U.S.C. 7410(l), which prohibits SIP revisions from interfering with attaining air quality standards and reasonable further progress requirements. IDEM's 110(l) demonstration describes how the oil cover layer will remain on top of the degreasing solvent and control emissions of VOCs by reducing solvent evaporation, which also reduces the heat required for operations as it acts similar to an insulator. The oil cover is expected to provide equivalent control of VOC emissions compared to the use of controls required by 326 IAC 8-3-2 and therefore has no adverse impact on air quality. The EPA concurs with the 110(l) demonstration that this action will not interfere with air quality standards and reasonable further progress requirements.

The EPA is proposing to approve revisions to VOC emissions regulations for the Keystone aluminum alloy wheel refurbishing and distribution facility in Huntington County, Indiana. More specifically, the EPA proposes to approve Commissioner's Order 2025-Air-01 into the Indiana SIP. The revision provides for the use of an oil cover as an equivalent VOC emission control system under 326 IAC 8-1-5 and 326 IAC 8-3-2 for its cold cleaner degreaser.

In this rulemaking, EPA is proposing to include in a final EPA rule regulatory text that includes incorporation by reference. In accordance with requirements of 1 CFR 51.5, the EPA is proposing to incorporate by reference Indiana Commissioner's Order 2025-Air-01, signed February 19, 2025, discussed in section IV of this preamble. The EPA has made, and will continue to make, these documents generally available through www.regulations.gov and at the EPA Region 5 Office (please contact the person identified in the FOR FURTHER INFORMATION CONTACT section of this preamble for more information).

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

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

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

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

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

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

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

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

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

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

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

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

The EPA has determined that ground-level ozone is detrimental to human health. On October 1, 2015, the EPA promulgated a revised 8-hour ozone NAAQS of 0.070 parts per million (ppm). See 80 FR 65292 (October 26, 2015). Under the EPA's regulations at 40 CFR part 50, the 2015 ozone NAAQS is attained in an area when the 3-year average of the annual fourth highest daily maximum 8-hour average concentration is equal to or less than 0.070 ppm, when truncated after the thousandth decimal place, at all of the ozone monitoring sites in the area. See 40 CFR 50.19 and appendix U to 40 CFR part 50.

Upon promulgation of a new or revised NAAQS, section 107(d)(1)(B) of the CAA requires the EPA to designate as nonattainment any areas that are violating the NAAQS, based on the most recent three years of quality-assured ozone monitoring data. The Cleveland area was designated as a Marginal nonattainment area for the 2015 ozone NAAQS on June 4, 2018 (83 FR 25776) (effective August 3, 2018). On October 7, 2022 (87 FR 60897), the EPA determined that the Cleveland area did not attain the standard by the Marginal attainment date, and the area was reclassified as Moderate by operation of law. More recently on December 17, 2024 (89 FR 101901), the EPA determined the area did not attain the standard by the Moderate attainment date, and the area was reclassified as Serious by operation of law.

Congress has recognized that it may not be appropriate for the EPA to use certain monitoring data collected by the ambient air quality monitoring network and maintained in the EPA's Air Quality System (AQS) database in certain regulatory determinations. Thus, in 2005, Congress provided the statutory authority for the exclusion of data influenced by “exceptional events” meeting specific criteria by adding section 319(b) to the CAA. 1

The EPA promulgated the Exceptional Events Rule on March 22, 2007 (72 FR 13560) to implement this 2005 CAA amendment. The 2007 Exceptional Events Rule created a regulatory process codified at 40 CFR parts 50 and 51 (sections 50.1, 50.14, and 51.930). These regulatory sections supersede the EPA's previous guidance on handling data influenced by events, and contain definitions, procedural requirements, requirements for air agency demonstrations, criteria for the EPA's approval of the exclusion of event-affected air quality data from the data set used for regulatory decisions, and requirements for air agencies to take appropriate and reasonable actions to protect public health from exceedances or violations of the NAAQS. On October 3, 2016 (81 FR 68216), the EPA promulgated a comprehensive revision to the 2007 Exceptional Events Rule. The 2016 Exceptional Events Rule revision included the requirement that, if a State demonstrates that emissions from a wildfire smoke event caused a specific air pollution concentration in excess of the NAAQS at a particular air quality monitoring location and otherwise satisfies the requirements of 40 CFR 50.14, the EPA must exclude that data from the use in determinations of exceedances and violations. 2

The CAA provides for the exclusion of air quality monitoring data from design value calculations when there are NAAQS exceedances caused by events, such as wildfires, that meet the criteria for an exceptional event identified in the EPA's Exceptional Events Rule at 40 CFR 50.1, 50.14, and 51.930. For the purposes of this proposed action, on December 8, 2025, Ohio EPA submitted an exceptional events demonstration showing that ozone concentrations recorded at the Cuyahoga County monitors at District 6 with Site ID 39-035-0034 on June 1, 2, and 29, 2023, and at GT Craig Ncore PAMS with Site ID 39-035-0060 on June 1, 2, and 29, 2023, and ozone concentrations recorded at the Lake County monitors at Eastlake with Site ID 39-085-0003 on June 1 and 2, 2023, and at Painesville with Site ID 39-085-0007 on June 1 and 2, 2023, were influenced by wildfires. The EPA concurred on this request on January 12, 2026.

The EPA found that Ohio's demonstration met the Exceptional Events Rule criteria by demonstrating a clear, causal relationship between these wildfire events and the recorded high ozone values in the area. These values have regulatory significance for purposes of calculating the area's most recent air quality design value needed to demonstrate that the area is attaining the ozone air quality standard. Therefore, the EPA is proposing to take final agency action to approve the CDD for the Cleveland nonattainment area. Consistent with CAA section 319(b) and the implementing regulations, the EPA will remove the monitoring data influenced by exceptional events from the dataset used for regulatory purposes. For this proposed action, the EPA will rely on the calculated values that exclude the event-influenced data for the purpose of demonstrating attainment of the 2015 ozone NAAQS. Further details on Ohio's analyses and the EPA's concurrence can be found in the docket for this regulatory action.

While the EPA has concurred with Ohio's request to exclude event-influenced air quality monitoring data from regulatory decisions, the EPA must provide an opportunity for public comment on the claimed exceptional events and all supporting data prior to the EPA taking final regulatory action which relies on the revised data set. This proposed action provides the public with an opportunity to comment on the claimed exceptional events, all supporting documents and the EPA's concurrence with Ohio's request.

Following enactment of the CAA Amendments of 1990, the EPA discussed its interpretation of the requirements for implementing the NAAQS in the General Preamble for the Implementation of title I of the CAA Amendments of 1990 (General Preamble), 57 FR 13498, 13564 (April 16, 1992). On November 29, 2005 (70 FR 71612), the EPA set forth what has become known as its “Clean Data Policy” for the 1-hour ozone NAAQS. Under the Clean Data Policy, for a nonattainment area that can demonstrate attainment of the standard before implementing CAA nonattainment measures, the EPA interprets the requirements of the CAA that are specifically designed to help an area achieve attainment, such as the requirements for such area to submit attainment demonstrations and associated RACM, RFP plans, contingency measures for failure to attain or make reasonable progress, and other planning SIPs related to attainment of the ozone NAAQS, to be suspended for as long as air quality continues to meet the standard. Such a determination of attainment under the Clean Data Policy is known informally as a CDD. On December 6, 2018 (83 FR 62998), in the final rule updating implementing regulations for the 2015 ozone NAAQS, the EPA codified this policy at 40 CFR 51.1318.

An area is attaining the 2015 ozone NAAQS if it meets the 2015 ozone NAAQS, as determined in accordance with 40 CFR 50.19 and appendix U of part 50, based on three complete, consecutive calendar years of quality-assured air quality data for all monitoring sites in the area. To attain the 2015 ozone NAAQS, the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentrations (ozone design values) at each monitor must not exceed 0.070 ppm. The air quality data must be collected and quality-assured in accordance with 40 CFR part 58 and recorded in the EPA's AQS. Ambient air quality monitoring data for the 3-year period must also meet data completeness requirements. An ozone design value is valid if daily maximum 8-hour average concentrations are available for at least 90% of the days within the ozone monitoring seasons, 3 on average, for the 3-year period, with a minimum data completeness of 75% during the ozone monitoring season of any year during the 3-year period. See section 4 of appendix U to 40 CFR part 50.

The EPA has reviewed the available ozone monitoring data from Ohio EPA's monitoring sites in the Cleveland area for the 2023-2025 period. These data were quality assured, recorded in the AQS, and certified in advance of the EPA's publication of this proposal. Ambient air quality monitoring data for the three-year period must meet a data completeness requirement. The EPA did not include data from the Cuyahoga County monitor at Mayfield (site ID: 39-035-5002), which was shut down in 2025 after meeting regulatory requirements and receiving approval from the EPA. The annual fourth-highest 8-hour ozone concentrations and the 3-year average of these concentrations (monitoring site ozone design values) for all valid monitoring sites are summarized in Table 1. These data demonstrate that the Cleveland area is attaining the 2015 ozone NAAQS.

The Cleveland area's 3-year ozone design value for 2023-2025 is 0.070 ppm, 4 which meets the 2015 ozone NAAQS. Therefore, in this action, the EPA proposes to find that the Cleveland area is attaining the 2015 ozone NAAQS.

Should this action be finalized, the requirements for Ohio EPA to submit attainment demonstrations and associated RACM, RFP plans, contingency measures for failure to attain or make reasonable progress, and other planning SIPs related to attainment of the 2015 ozone NAAQS for the Cleveland area, would be suspended for as long as the area continues to attain the 2015 ozone NAAQS. 40 CFR 51.1318.

This action does not constitute a determination of attainment by the attainment date under CAA section 181(b)(2). In this action the EPA is considering the area's design value for the 2023-2025 period, which is not the area's design value as of the applicable attainment date.

The EPA will not take final action to determine that the Cleveland area is attaining the NAAQS if the design value of a monitoring site in the area violates the NAAQS prior to final approval of the CDD.

This action does not constitute a redesignation of any portion of the area to attainment of the 2015 ozone NAAQS under section 107(d)(3)(E) of the CAA, nor does it constitute approval of a maintenance plan for any portion of the area as required under section 175A of the CAA, nor does it find that any portion of the area has met all other requirements for redesignation. On December 8, 2025, Ohio submitted a request to redesignate the area to attainment for the 2015 ozone NAAQS under CAA section 107(d)(3)(E), and the EPA will take action on Ohio's request in a separate rulemaking. The Cleveland area will remain designated nonattainment for the 2015 ozone NAAQS until such time as the EPA determines that the Cleveland area meets CAA requirements for redesignation to attainment and takes a separate action to redesignate the Cleveland area.

The EPA is proposing to approve a determination under the CAA that the Cleveland area has attained the 2015 ozone NAAQS. This determination is based upon complete, quality-assured, and certified ambient air monitoring data for the 2023-2025 design period showing that the area achieved attainment of the 2015 ozone NAAQS. The EPA is also proposing to take final agency action on an exceptional events request submitted by Ohio EPA on December 8, 2025, and concurred upon by the EPA on January 12, 2026. As a result of this determination and pursuant to 40 CFR 51.1318, the EPA is proposing to suspend the requirements for the area to submit attainment demonstrations and associated RACM, RFP plans, contingency measures for failure to attain or make reasonable progress, and other planning SIPs related to attainment of the 2015 ozone NAAQS, for as long as the area continues to attain the 2015 ozone NAAQS.

Additional information about these statutes and Executive Orders can be found at https://www.epa.gov/lawsregulations/laws-and-executive-orders.

This action is not a significant regulatory action and was therefore not submitted to the Office of Management and Budget (OMB) for review. This action proposes to issue a CDD for the Cleveland area for the 2015 ozone NAAQS.

Executive Order 14192 does not apply because it is not a significant regulatory action and is therefore exempted from review under Executive Order 12866.

This rule does not impose an information collection burden under the provisions of the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 et seq. )

I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA. This action will not impose any requirements on small entities beyond those imposed by state law. The proposed CDD does not create any new requirements and does not directly regulate any entities.

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

This action does not have federalism implications. It will not have substantial direct effects on the states, on the relationship between the national government and the states, or on the distribution of power and responsibilities among the various levels of government. This action proposes a CDD for the Cleveland nonattainment area under the CAA.

This rule does not have Tribal implications, as specified in Executive Order 13175. It will not have substantial direct effects on Tribal governments. Thus, Executive Order 13175 does not apply to this rule.

The EPA interprets Executive Order 13045 as applying only to those regulatory actions that concern environmental health or safety risks that the EPA has reason to believe may disproportionately affect children, per the definition of “covered regulatory action” in section 2-202 of the Executive Order. Therefore, this action is not subject to Executive Order 13045 because it merely proposes a CDD.

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

Inspection of Public Comments: All comments received before the close of the comment period are available for viewing by the public, including any personally identifiable or confidential business information that is included in a comment. We post all comments received before the close of the comment period on the following website as soon as possible after they have been received: http://www.regulations.gov. Follow the search instructions on that website to view public comments. CMS will not post on Regulations.gov public comments that make threats to individuals or institutions or suggest that the commenter will take actions to harm an individual. CMS continues to encourage individuals not to submit duplicative comments. We will post acceptable comments from multiple unique commenters even if the content is identical or nearly identical to other comments. CMS encourages commenters to include supporting facts, research, and evidence in their comments. When doing so, commenters are encouraged to provide citations to the materials referenced, including active hyperlinks. Likewise, commenters who reference materials that have not been published are encouraged to upload relevant data collection instruments, data sets, and detailed findings as a part of their comment. Providing such citations and documentation will assist CMS in analyzing the comments.

On June 6, 2025, President Trump issued a Presidential Memorandum on Eliminating Waste, Fraud, and Abuse in Medicaid expressing this Administration's commitment to preserve and protect the integrity of government programs. Similarly, President Trump, U.S. Department of Health and Human Services (HHS) Secretary Kennedy, and Centers for Medicare & Medicaid Services (CMS) Administrator Oz have strongly demonstrated this administration's dedication to crushing fraud in Medicare, Medicaid, the Children's Health Insurance Program (CHIP), and the Marketplace. In alignment with this strategic objective, CMS is issuing this RFI to solicit stakeholder feedback on potential regulatory changes that might be included in a potential future proposed rule, as well as other programmatic changes that could be implemented to make CMS more effective in crushing fraud to protect taxpayer dollars and the Americans we serve.

While CMS invites all relevant input, we are specifically inviting responses on the following topics listed in this section of this RFI. This RFI does not necessarily solicit comments on the full scope of topics that could be included in a potential, future CRUSH Rule.

CMS takes a variety of actions to crush fraud, waste and abuse, including provider enrollment screening, suspending payments when there is a credible allegation of fraud or reliable indication of overpayment, data analytics of claims, imposing automatic pre-payment claims edits, conducting investigations and audits, post-payment review of medical records, revocations, re-enrollment bans, coordinating with law enforcement partners on enforcement actions, and providing education to reduce improper payments. CMS is looking for ways to strengthen its fraud-fighting toolbox and invites public comments on how to achieve this. Specifically, we seek comments on the following questions and related topics around CMS' existing program integrity authorities and processes:

• Are there ways in which CMS could better use existing statutory authorities to expeditiously prevent bad actors from engaging in fraud, waste, and abuse?

• Are there ways to modify provider enrollment (including revocation), medical review, investigation, audit, payment suspension, and other program integrity oversight policies to provide CMS with increased authority and flexibility to expeditiously prevent bad actors from engaging in fraud, waste, and abuse? (See, for example, Title 42 Code of Federal Regulations (CFR) 405.371 et seq. (payment suspension), part 424, Subpart P, especially 424.510 (general requirements), 424.516 (additional requirements), 424.530 (enrollment denial), 424.535 (revocation), and 424.540 (deactivation of billing privileges).)

• Are there existing requirements or policies, including those issued through regulations, memoranda, administrative orders, subregulatory guidance documents, or policy statements that could be altered to increase CMS' ability to promote payment accuracy and efficiency to protect the integrity of Medicare, Medicaid, CHIP, and the Health Insurance Marketplace®?  1

• What changes could CMS or its contractors make to existing processes to promote their ability to effectively deter fraud, waste, and abuse and promote payment accuracy and efficiency, including by more expeditiously gathering actionable information?

• What types of analytics, methodologies, or data-driven approaches would be most effective in identifying indicators of potential fraud, waste, or abuse? We welcome feedback on specific analytical techniques, models, technologies, mechanisms, or data sources that could strengthen our ability to proactively detect and prevent fraudulent activity.

• A core component of crushing fraud to protect taxpayer dollars is transparency to the Americans we serve about CMS' program integrity undertakings. How can CMS improve its transparency about its oversight and enforcement activities?

• CMS currently does not have an affirmative, regulatory authority to direct Medicare Advantage (MA) organizations and Part D plan sponsors to suspend payments to providers and suppliers that operate exclusively in Part C or Part D or both. Should CMS establish regulatory requirements that allow MA organizations and Part D sponsors to implement payment suspensions under circumstances similar to the payment suspension authority that exists for Traditional Medicare under 42 CFR 405.371, and require suspensions when directed by CMS?

CMS has identified significant concerns that Medicare fraud is increasingly perpetrated through international fraud schemes characterized by opacity of ownership structures. These schemes often involve owners who reside outside of the United States, owners who are not permanent residents or U.S. citizens, and individuals who operate beyond the reach of U.S. law enforcement authorities. The lack of robust identity verification and the ability of non-U.S. residents to maintain ownership in Medicare-enrolled entities creates substantial program integrity vulnerabilities and impedes fraud investigation and prosecution efforts. CMS is seeking stakeholder feedback on potential provisions that would require enhanced identity proofing of individuals associated with Medicare-enrolled entities and impose citizenship or legal residency requirements for ownership.

• What would be the impact on Medicare-enrolled entities if CMS established a requirement for U.S. citizenship or legal permanent residency for all individuals with an ownership or control interest of 5 percent or greater in a Medicare-enrolled provider or supplier?

• CMS currently requires fingerprinting and criminal background checks for all individuals with a 5 percent or greater ownership interest in a provider/supplier organization that is part of the “high” risk category as described in 42 CFR 424.518. Should this be expanded to include, for instance, the provider's managing employees, less than 5 percent owners, or other individuals who are affiliated with or working for the organization?

• What alternative identity proofing measures could effectively verify the identity and location of owners while balancing program integrity objectives with the operational needs of legitimate Medicare providers and suppliers?

• Are there specific provider or supplier types for which enhanced identity proofing and citizenship or residency requirements would be most critical to preventing fraud?

• Are there additional individuals on the enrollment record for whom enhanced identity proofing and citizenship or residency requirements would help prevent fraud?

• What challenges would these requirements create for entities with foreign parent companies, international investors, or legitimate cross-border business structures?

CMS has identified significant deficits in the effectiveness of the preclusion list in preventing fraudulent billing in MA. Under current policy, providers and suppliers that are revoked from Traditional Medicare for reasons not considered “detrimental to the best interests of the Medicare program” are not included on the preclusion list. CMS has observed that providers and suppliers revoked from Traditional Medicare for these reasons often shift their billing operations to MA plans, where they can continue to submit claims and receive payment. This gap in the preclusion list undermines program integrity efforts and allows bad actors to circumvent CMS oversight. CMS is seeking feedback from MA organizations and other stakeholders on potential improvements to the preclusion list and whether requiring enrollment in Traditional Medicare could enhance program integrity.

• What changes could CMS make to better effectuate the preclusion list to prevent Traditional Medicare-revoked providers and suppliers from continuing to bill MA plans?

• Does the current preclusion list adequately serve the needs of MA organizations in identifying and preventing payments to providers and suppliers that pose fraud, waste, or abuse risks?

• Would MA plans support a requirement for all providers and suppliers to enroll in the Traditional Medicare (Fee-for-Service) program as a condition of billing MA plans?

• Should such a requirement apply only to high-risk provider and supplier types?

• What operational, administrative, and financial impacts would a requirement to enroll in the Traditional Medicare program have on providers and suppliers that currently only bill MA plans?

• Are there alternative mechanisms that could achieve similar program integrity objectives without requiring enrollment in Traditional Medicare?

In 2024, Medicare Part B or Traditional Medicare spending on clinical diagnostic laboratory tests (lab tests) totaled $8.4 billion—a five percent increase over the previous year per a January 2026 U.S. Department of Health and Human Services' Office of the Inspector General (OIG) Report. 2 Part B spending on lab tests has been shifting increasingly toward genetic tests, including tests related to cancer, infections, and epilepsy. 3 Although genetic tests represented only 5 percent of lab tests paid under Part B in 2024, they accounted for 43 percent ($3.6 billion) of Part B lab spending. The OIG and the Department of Justice have issued multiple reports  4 and fraud alerts, 5 and have engaged in multiple enforcement actions  6 related to fraud in lab tests, particularly genetic tests, including molecular diagnostic tests. CMS is concerned about fraud, waste, and abuse related to lab tests and has targeted this as a focus area through its Fraud Defense Operations Center (FDOC), which is a high-tech unit formed in 2025 that utilizes cross-functional teams to target fraud in real time and has expedited the issuance of payment suspensions, resulting in $1.8 billion in taxpayer savings in 2025, over $100 million of which was related to suspect laboratories.

• What new statutory or regulatory authorities would empower CMS to more effectively prevent, identify, and address fraud in lab tests, including genetic tests and molecular diagnostic tests?

• What types of tools, data analytics, and methods would assist CMS to increase program integrity related to lab tests, including genetic tests and molecular diagnostic tests?

In 2011, the Molecular Diagnostic Services Program (MolDX Program), administered by Palmetto GBA on behalf of CMS, was established to determine and streamline coverage and reimbursement for molecular diagnostic tests on behalf of the Medicare program. It aims to provide uniform policies across multiple Medicare Administrative Contractors (MACs) and currently spans 28 states.

CMS is interested in understanding if a requirement to register in the MolDX program, that other payors may have, has had an impact on the risk of fraud, waste and abuse related to laboratory testing. CMS also wants to understand the rationale as to why other payors and MA organizations require laboratories to be registered in MolDX even when they are not located in a MolDX state.

• What prompted other payors and MA organizations to require registration in the MolDX program?

• What safeguards or challenges has the MolDX program provided to your organization regarding laboratory testing?

There is a significant risk of fraud, waste, and abuse with certain high-risk services, including the provision of DMEPOS. The OIG and MA organizations have identified that non-participating DMEPOS suppliers  8 are fraudulently billing MA plans for millions of dollars of services not rendered and not needed. 9 We would like the public's feedback on solutions related to non-participating DMEPOS suppliers in MA.

• What changes would MA organizations need to make to existing processes to promote the ability to effectively deter fraud, waste, and abuse and promote payment accuracy for non-participating DMEPOS suppliers?

• Are there existing requirements (including those issued through regulations, memoranda, administrative orders, guidance documents, contracts, or policy statements) that could be altered to increase MA organizations' ability to promote payment accuracy and efficiency to protect the integrity of the program for non-participating DMEPOS suppliers?

• What types of analytics, methodologies, or data-driven approaches are most effective in identifying indicators of potential fraud, waste, or abuse for non-participating DMEPOS suppliers? We welcome feedback on specific analytical techniques, models, or data sources that could strengthen MA organizations' ability to proactively detect and prevent fraudulent activity.

• Would MA organizations prefer DMEPOS suppliers to be accredited and enrolled similar to Traditional Medicare, ensuring suppliers meet minimum supplier standards?

Due to the significant risk of fraud, waste, and abuse with certain high-risk items and services (for example, DMEPOS), CMS is seeking feedback about the impact of reducing the Medicare Parts A and B (Traditional Medicare) 1-calendar year claim filing deadline for high-risk items and services, including but not limited to DMEPOS. Ensuring claims are filed more promptly will assist CMS in evaluating data and reduce the ability of providers to back-bill for fraudulent claims.

• How would a claim filing deadline of 90 to 180 calendar days, which is consistent with private industry norms, impact your practice?

• Are there certain claim or provider types for which these deadlines would not be feasible?

• What would be the best way to implement a shorter claim filing deadline for certain high-risk items and services? What are the benefits or drawbacks of imposing a shorter claim filing deadline for all of the following:

++ All claims filed by specific high-risk provider or supplier types (for example DMEPOS suppliers).

++ All claims filed for specific high-risk items or services.

++ All claims filed by specific providers who are high-risk.

++ Some other method(s).

• Would it be beneficial to apply this standard to all items and services rather than only to high-risk items and services to reduce unnecessary administrative complexity?

• Would the current flexibilities in 42 CFR 424.44 or additional flexibilities for a shorter claim filing deadline be appropriate to support such a change, and if so, what would those flexibilities be?

CMS is seeking input from stakeholders about the availability, use, efficacy, and cost of using artificial intelligence (AI), based on machine learning and other methods, to assist with accurately and efficiently abstracting diagnoses from medical record documentation as part of a medical records review. More specifically, CMS is seeking input on the following topics:

• What types of AI solutions (including commercial off-the-shelf (COTS) products) are most effective and efficient for assisting human coders with large volumes of records?

• What key features and learning capabilities should an AI solution include to improve accuracy, incorporate coder feedback, and prevent errors or “hallucinations”?

• How should AI-generated coding recommendations be displayed to human reviewers, and what compliance risks should be considered and mitigated?

• What lessons have been learned from implementing AI solutions, including pricing structures and use within cloud-based IT environments?

• Are there AI solutions that address coding issues related to overpayments and underpayments, and can those AI solutions be used for compliance oversight?

• How could AI be used to increase the efficiency and accuracy of hospital billing?

Medicare beneficiaries are often subject to unsolicited outreach by unscrupulous individuals seeking to obtain their personally identifiable information to submit fraudulent Medicare claims. Beneficiaries are sometimes offered free money, items, or services in exchange for their information. There is currently a prohibition against unsolicited contact via telephone by DMEPOS suppliers ( see section 1834(a)(17) of the Social Security Act (the Act) and 42 CFR 424.57(c)(11)). We are seeking feedback from stakeholders about the impact of expanding this prohibition to other types of providers and suppliers through legislation and expanding the existing DMEPOS regulation to other forms of communication, such as email, text message, or social media.

• What means of communication do Medicare beneficiaries find are being used to solicit them for their Medicare information? How do beneficiaries respond when they have been contacted by an inappropriate direct solicitation?

• If the prohibition on unsolicited contact via telephone by DMEPOS suppliers was expanded to other forms of communication, what obstacles would that create for DMEPOS suppliers that could hinder your ability to effectively serve Medicare beneficiaries? In what ways could CMS mitigate those concerns while still expanding protections for beneficiaries?

• If CMS were to pursue a legislative proposal to expand the prohibition against unsolicited contact by DMEPOS suppliers to other provider and supplier types, are there other provider or supplier types that should be included?

• In what other ways should CMS expand the prohibition on unsolicited contact via telephone by DMEPOS suppliers? For example, should CMS explicitly prohibit DMEPOS suppliers from collaborating with marketing agencies or other third parties acting on their behalf to perform solicitation?

CMS encourages Medicare beneficiaries or their authorized legal representatives to review their Medicare Summary Notices (MSNs) and other CMS-issued materials, such as the Medicare & You handbook (see page 105 available at www.medicare.gov/publications/10050-medicare-and-you.pdf ) and the CMS website to identify services or items that may be incorrect, unfamiliar, or potentially fraudulent. These communications include instructions on how beneficiaries can report suspected fraud, waste, or abuse, including contacting CMS, the MACs, or the OIG. While these existing efforts provide important information and reporting pathways, we are interested in understanding whether additional or alternative communication methods could further improve beneficiary awareness, trust, and ease of reporting. Accordingly, we are exploring whether and how other approaches or tools could be utilized to better support beneficiaries in identifying and reporting potentially suspicious Traditional Medicare claims.

• How would beneficiaries prefer to be contacted by CMS or its contractors about potentially suspicious claims? Would they prefer that this contact occur before or after processing the claim?

• What concerns, if any, would beneficiaries have regarding privacy, burden, or confusion related to prepayment verification outreach? In what ways could CMS distinguish these communications to make them easy to identify and to make it clear that they are legitimate and trustworthy communications and that beneficiaries need to take action? What form(s) of communication (for example, telephone, mail, secure electronic communication) would beneficiaries find acceptable for such verification?

• What could CMS be doing that it is not already doing to make it easier for beneficiaries to report a potentially suspicious claim?

In accordance with section 1834(a)(16) of the Act (and as codified in 42 CFR 424.57(d)), DMEPOS suppliers are required to maintain a surety bond of at least $50,000 in order to enroll and maintain enrollment in Medicare. We request public feedback on means of strengthening our existing surety bond requirement. We are especially interested in suggestions on how CMS should use its surety bond authorities to be more effective in the fight against fraud, such as increasing the required bond amount, expanding the types of Medicare providers and suppliers that must maintain a surety bond, or taking tougher actions against bond companies that are not meeting their obligations when fraud is found. In addition, how can CMS strengthen surety bond requirements in Medicaid and CHIP, for example, with respect to Medicaid and CHIP home health providers?

Recently, CMS has taken bold steps to address significant, systemic Medicaid fraud that has been discovered in multiple states. CMS is continuously refining its oversight actions and capabilities to ensure that states are proactive in crushing fraudulent activities in these programs. We are seeking stakeholder feedback on how to expand CMS' regulatory authority to act expeditiously to prevent, identify, and address instances of fraud, waste, and abuse in Medicaid and CHIP. We are also soliciting suggestions about cutting-edge technological tools that could be harnessed to advance this work.

• Is there any way that CMS should better leverage or expand its statutory or regulatory program integrity oversight authority?

• In order to strengthen program integrity oversight of provider enrollment, should CMS require that states require their high-risk providers to revalidate more frequently than every 5 years, and if so, how frequently?

• What tools or technologies can CMS or states use to enhance program integrity in Medicaid, CHIP managed care, and fee-for-service programs?

• What tools or guidance can CMS give to states to enhance program integrity in the Medicaid and CHIP managed care and fee-for-service programs?

• What ways can CMS improve the prevention, identification, and resolution of fraud, waste, and abuse related to non-federal share financing sources, including intergovernmental transfers (IGT)?

• How can CMS better prevent, identify, and address Medicaid and CHIP fraud, waste, and abuse in the context of individuals who do not have satisfactory immigration status for full Medicaid or CHIP benefits who are accessing services inappropriately?

• How can CMS better prevent fraud, waste, and abuse associated with the differential payment of public and private providers?

• What data and information should states report to CMS to ensure that fraud, waste, and abuse is being identified, investigated, and resolved?

• What best practices and standardized processes should states implement when responding to recovery audit contractor (RAC) findings?

• What data or information should be made publicly available that would allow for transparency in Medicaid by states, health plans, and providers?

• How can CMS help states to better prevent, identify, and address Medicaid and CHIP fraud, waste, and abuse related to service areas that have been identified as high risk for fraud in certain states, such as the following:

++ Housing stabilization services.

++ Behavioral health services.

++ Personal care assistant (PCA) services.

++ Nonemergency medical transportation.

• How can CMS further enhance the Healthcare Fraud Prevention Partnership (HFPP) to strengthen fraud detection within state agencies and law enforcement?

• What are the best practices for integrating artificial intelligence with existing technologies to maximize effectiveness?

• What statutory or regulatory changes are needed to strengthen states' ability to effectively reduce fraud, waste, and abuse in Medicaid and CHIP?

• What regulatory or administrative changes could CMS make to empower states to—(a) pursue bad actors; and (b) better coordinate program integrity efforts with the federal government, law enforcement, and other states?

• What data or tools would facilitate state program integrity activities?

• Would further use of federal databases, such as Do Not Pay (DNP), or non-federal databases provide states with more complete information to move further away from a pay-and-chase model and towards pre-pay review?

• What successful strategies have certain states implemented that others can replicate as best practices?

• What is the best way for states to learn about the most up to date technology or data analytic tools available to effectively reduce fraud, waste, and abuse in Medicaid and CHIP?

• How can CMS help states better prevent, identify, and address fraud, waste, and abuse related to supplemental payments (for example, disproportionate share hospital (DSH) payments) or state directed payments?

• How can CMS help states better prevent, identify, and address fraud, waste, and abuse in section 1915 waiver programs or section 1115 demonstration programs?

• What incentives could be put in place for states to proactively engage in program integrity efforts, and what new penalties might be necessary to address non-compliance by states?

• How could CMS strengthen program integrity, including fraud prevention and consumer protection, in both the FFE and SBEs by—(1) better leveraging existing regulatory oversight authority; and (2) identifying areas where additional regulatory authority may be needed?

• How could CMS improve regulations to strengthen oversight of agents, brokers, web-brokers, and direct enrollment entities including compliance standards, training, and fraud prevention in both the FFE and SBEs?

• How could CMS expand its regulatory authority to incentivize insurance agencies to thoroughly vet assigned agents, brokers, and web-brokers assisting consumers with enrollment in FFE plans and hold agencies accountable for activities relating to these individuals?

• What specific measures could CMS implement to better curtail the ability of fraudulent agents, brokers, and web-brokers to enroll or change the enrollment of consumers without their knowledge or consent?

• How can CMS strengthen its enforcement activities to better address fraud, waste, and abuse in the FFE and SBEs?

• How could CMS strengthen its standards for corrective action and for suspension or termination of agents', brokers', and web brokers' Exchange Agreements  10 and what circumstances should trigger each type of action? Should CMS consider additional use of civil money penalties? If so, under what circumstances?

• How could CMS improve the accuracy, timeliness, fraud prevention, and any other aspects related to program integrity in income verification for FFE enrollees?

• What successful anti-fraud measures already implemented in SBEs should be adopted in the FFE and vice versa?

• How could CMS enhance HealthCare.gov to prevent fraud at the point of enrollment and reduce reliance on post-payment recovery (commonly referred to as “pay-and-chase”), and how could CMS most effectively encourage SBEs to adopt best practices for such fraud prevention within their legal and other authority?

• How could CMS expand its regulatory authority to enhance oversight of enhanced direct enrollment (EDE) partners?

• How could CMS expand its authority to monitor the activity of agents/brokers on EDE platforms?

• How could CMS better detect and mitigate improper dual enrollment in Medicaid/CHIP and subsidized Exchange plans?

• How could CMS leverage advanced technologies, such as AI, to prevent, detect, and address fraud, waste, and abuse in both the FFE and SBEs?

This is an RFI only. In accordance with the implementing regulations of the Paperwork Reduction Act of 1995 (PRA), specifically 5 CFR 1320.3(h)(4), this general solicitation is exempt from the PRA. Facts or opinions submitted in response to general solicitations of comments from the public, published in the Federal Register or other publications, regardless of the form or format thereof, provided that no person is required to supply specific information pertaining to the commenter, other than that necessary for self-identification, as a condition of the agency's full consideration, are not generally considered information collections and therefore not subject to the PRA.

This RFI is issued solely for information and planning purposes; it does not constitute a Request for Proposal (RFP), applications, proposal abstracts, or quotations. This RFI does not commit the U.S. Government to contract for any supplies or services or make a grant award. Further, we are not seeking proposals through this RFI and will not accept unsolicited proposals. Responders are advised that the U.S. Government will not pay for any information or administrative costs incurred in response to this RFI; all costs associated with responding to this RFI will be solely at the interested party's expense. We note that not responding to this RFI does not preclude participation in any future procurement, if conducted. It is the responsibility of the potential responders to monitor this RFI announcement for additional information pertaining to this request. In addition, we note that CMS will not respond to questions about the policy issues raised in this RFI.

We will actively consider all input as we develop future regulatory proposals or future subregulatory policy guidance. We may or may not choose to contact individual responders. Such communications would be for the sole purpose of clarifying statements in the responders' written responses. Contractor support personnel may be used to review responses to this RFI. Responses to this notice are not offers and cannot be accepted by the Government to form a binding contract or issue a grant. Information obtained as a result of this RFI may be used by the Government for program planning on a non-attribution basis. Respondents should not include any information that might be considered proprietary or confidential. This RFI should not be construed as a commitment or authorization to incur cost for which reimbursement would be required or sought. All submissions become U.S. Government property and will not be returned. In addition, we may publicly post the public comments received, or a summary of those public comments.