AGENCY:

Pipeline and Hazardous Materials Safety Administration (PHMSA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

This final rule removes undue regulatory burdens by adopting the provisions of U.S. Department of Transportation (DOT) special permit (SP) 21379 to streamline the transportation of refrigerating machines and components containing certain low flammability refrigerant gases.

DATES:

Effective date: This final rule is effective September 3, 2026.

Incorporation by reference date: The incorporation by reference of certain material listed in this rule is approved by the Director of the Federal Register as of September 3, 2026.

The incorporation by reference of certain other material listed in the rule was approved by the Director of the Federal Register as of January 1, 2004 and December 28, 2020.

FOR FURTHER INFORMATION CONTACT:

Candace Casey, Standards and Rulemaking Division, Pipeline and Hazardous Materials Safety Administration (PHMSA), 1200 New Jersey Avenue SE, Washington, DC 20590, 202-366-8553, candace.casey@dot.gov.

I. PHMSA Action

A. What action is PHMSA taking in this final rule?

PHMSA is adopting the provisions of DOT SP 21379 into the Hazardous Materials Regulations (HMR; 49 CFR parts 171-180) by revising 49 CFR 173.306 to streamline the transportation of refrigerating machines containing certain low flammability refrigerant gases ( i.e., refrigerants). This revision allows up to 5,000 lbs. of low flammability refrigerants in refrigerating machines if they are a Category 1B refrigerant as specified in the Globally Harmonized System (GHS) of Classification and Labelling of Chemicals (which PHMSA is incorporating by reference) or a Group A2L refrigerant as specified in American National Standards Institute/American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ANSI/ASHRAE) Standard 34. PHMSA is also incorporating by reference ANSI/ASHRAE Standard 34-2024, Designation and Safety Classification of Refrigerants, which refers users to the list of flammable gases eligible for this exception.

B. Does this action apply to me?

Effective 30 days after publication of this final rule, offerors and carriers of affected refrigerating machines may begin to transport these products in accordance with the exceptions in 49 CFR 173.306 without expending the time and resources associated with obtaining a special permit.

C. Why is PHMSA taking this action?

PHMSA is taking this action in response to commenter feedback and to ( printed page 49316) streamline the transportation of refrigerating machines, or their components, containing certain flammable gases by adopting the provisions in DOT SP 21379. This change facilitates the transport of large refrigerating machines affected by the American Innovation and Manufacturing (AIM) Act, which required manufacturers to transition away from certain hydrofluorocarbon (HFC) refrigerants and replace them with refrigerants that were regarded as less damaging to the environment.^[1] This action allows the HMR to account better for the more widespread use of certain refrigerants following the new requirements imposed by the AIM Act. PHMSA is also taking this action as part of its ongoing review of special permits that are appropriate for adoption into the HMR based on their safety record and positive impact on stakeholders.

II. Incorporation by Reference Discussion Under 1 CFR Part 51

According to the Office of Management and Budget (OMB), Circular A-119, Federal Participation in the Development and Use of Voluntary Consensus Standards and in Conformity Assessment Activities, government agencies must use voluntary consensus standards wherever practical in the development of regulations.

PHMSA currently incorporates by reference into the HMR all or parts of numerous standards and specifications developed and published by standards development organizations (SDO). In general, SDOs update and revise their published standards every two to five years to reflect modern technology and best technical practices. The National Technology Transfer and Advancement Act of 1995 (NTTAA; Pub. L. 104-113) directs Federal agencies to use standards developed by voluntary consensus standards bodies in lieu of government-written standards whenever possible. Voluntary consensus standards bodies develop, establish, or coordinate technical standards using agreed-upon procedures. OMB issued Circular A-119 to implement section 12(d) of the NTTAA relative to the utilization of consensus technical standards by Federal agencies. This circular provides guidance for agencies participating in voluntary consensus standards bodies and describes procedures for satisfying the reporting requirements in the NTTAA. Accordingly, PHMSA is responsible for determining which standards currently referenced in the HMR should be updated, revised, or removed, and which standards should be added to the HMR. Revisions to materials incorporated by reference in the HMR are handled via the rulemaking process, which allows for the public and regulated entities to provide input.

During the rulemaking process, PHMSA must also obtain approval from the Office of the Federal Register to incorporate by reference any new materials. The Office of the Federal Register issued a rulemaking that revised 1 CFR 51.5 to require that an agency detail in the preamble of a notice of proposed rulemaking (NPRM) the ways the materials it proposes to incorporate by reference are reasonably available to interested parties, or how the agency worked to make those materials reasonably available to interested parties.^[2] In this final rule, PHMSA is incorporating by reference ANSI/ASHRAE Standard 34-2024, “ Designation and Safety Classification of Refrigerants, copyright 2024, including addenda approved through August 30, 2024.” ANSI/ASHRAE Standard 34-2024 establishes a uniform system for assigning unambiguous reference numbers, safety classifications (based on toxicity and flammability), and refrigerant concentration limits to refrigerants. This document is available for viewing at: https://www.ashrae.org/​technical-resources/​standards-and-guidelines/​read-only-versions-of-ashrae-standards. Documents are available for purchase at the ASHRAE bookstore at: https://store.accuristech.com/​ashrae/​ashrae_​standards.html.

PHMSA is also incorporating by reference Globally Harmonized System of Classification and Labelling of Chemicals, 9th Revised Edition, ST/SG/AC.10/30/Rev.9 (2021). This document serves as the international standard for defining and classifying chemical hazards (physical, health, and environmental) and communicating safety information through harmonized labels and Safety Data Sheets (SDS). ANSI/ASHRAE Standard 34-2024 and the Globally Harmonized System of Classification and Labelling of Chemicals, 9th Revised Edition can be reasonably obtained by interested parties through the applicable publisher contact information listed in § 171.7.

The following standards appear in the amendatory text of this document and were previously approved for the locations in which they appear: ANSI/ASHRAE Standard 15-1994 and Section VIII of the ASME Code.

III. Summary of Comments Received in Response to the Notice of Proposed Rulemaking

PHMSA published an NPRM, cited as HM-268N, to gather feedback on adopting the provisions of DOT SP 21379 into the HMR.^[3] Please refer to the NPRM for background and discussion of the proposed change.

The following table alphabetically lists commenters to the NPRM:

PHMSA received four sets of comments in response to the NPRM, and the comments were largely supportive of the amendments as proposed. However, some commenters had additional questions or suggestions related to the NPRM proposal.

First, ASHRAE expressed support for the proposed amendments but requested that PHMSA incorporate by reference the 2024 editions of both ANSI/ASHRAE Standards 15 and 34 in the relevant sections of the HMR. With respect to ANSI/ASHRAE Standard 15, Safety Code for Mechanical Refrigeration, PHMSA did not propose any changes to its current incorporation by reference and—therefore—the suggested change is considered beyond the scope of this rulemaking. However, PHMSA will consider this recommendation in a future rulemaking. With respect to ANSI/ASHRAE Standard 34, though the NPRM did not propose to incorporate by reference the 2024 edition, PHMSA agrees that using this more recent version to include additional refrigerants that would otherwise not be eligible if the 2019 edition were incorporated by reference ( printed page 49317) is appropriate. Moreover, PHMSA sees no safety concern with incorporating by reference the 2024 edition of ANSI/ASHRAE Standard 34 (instead of the proposed 2019 edition) for determination of eligible refrigerants.

Second, while supportive of the proposed amendments, COSTHA notes the provisions are limited to highway and rail only and may impact transporting refrigerating machines to remote areas in the United States ( i.e., certain areas in Alaska) where air service is the only practical means of transportation. Similarly, COSTHA asked whether PHMSA intends to allow—or continue to restrict—vessel transportation under the exceptions for refrigerating machines. PHMSA recognizes that continuing to limit eligibility for exceptions to transportation by highway and rail may complicate the logistics of transporting these items to remote areas. However, PHMSA notes that, given the limited experience authorizing these items for vessel and air transportation, it is more appropriate at this time to continue permitting such transportation on a case-by-case basis through special permits, rather than codifying a general provision applicable to all modes. Once PHMSA gets more experience with these non-ground modes, we may consider this recommendation in a future rulemaking.

Lastly, an anonymous commenter recommended that PHMSA prohibit the manufacture, use, and transportation of “Group A1” refrigerants, and instead promote “more environmentally friendly products.” Although PHMSA regulates the transportation of hazardous materials such as the refrigerants at issue here, PHMSA notes that the ability to prohibit the manufacture and use of any substance is beyond the scope of our Agency's authority.

For these reasons, PHMSA is revising 49 CFR 173.306 to allow up to 5,000 lbs. of a flammable, non-toxic gas, classified Category 1B in accordance with GHS or classified as an A2L refrigerant as specified in ANSI/ASHRAE Standard 34. PHMSA is also incorporating by reference ANSI/ASHRAE Standard 34 into 49 CFR 173.306.

Two additional editorial notes. First, at the proposed rule stage, PHMSA inadvertently omitted a cross-reference to 49 CFR 173.306 for the GHS Classification and Labelling of Chemicals publication in 49 CFR 171.7(dd)(3). Importantly, PHMSA included the full intent in the preamble and the substantive proposed regulatory text was correctly placed in 49 CFR 173.306. This text would add GHS criteria for Category 1B as an alternative criterion for eligibility for exception. PHMSA has determined that this additional editorial cross-reference revision to 49 CFR 171.7(dd)(3) is within the scope of this final rule and does not create a substantive amendment. Second, note also that the NPRM discussed the incorporation by reference of the 7th revised edition of the GHS of Classification and Labelling of Chemicals which was a typo. PHMSA meant the 9th revised edition, as the 9th revised edition is the correct version and is already incorporated by reference in the HMR.

IV. Regulatory Analysis and Notices

A. Legal Authority

This final rule is published under the authority of the Secretary of Transportation as set forth in the Federal Hazardous Materials Transportation laws (49 U.S.C. 5101 et seq.) and delegated to the PHMSA Administrator pursuant to 49 CFR 1.97.

B. Executive Order 12866; Regulatory Planning and Review

Executive Order (E.O.) 12866 ( Regulatory Planning and Review), as implemented by 49 CFR part 5, subpart B, requires agencies to regulate in the “most cost-effective manner,” to make a “reasoned determination that the benefits of the intended regulation justify its costs,” and to develop regulations that “impose the least burden on society.” ^[4] In arriving at those conclusions, E.O. 12866 requires that agencies should consider “both quantifiable measures . . . and qualitative measures of costs and benefits that are difficult to quantify” and “maximize net benefits . . . unless a statute requires another regulatory approach.” E.O. 12866 also requires that “agencies should assess all costs and benefits of available regulatory alternatives, including the alternative of not regulating.” Pursuant to 49 CFR part 5, subpart B, PHMSA and other Operating Administrations must generally choose the “least costly regulatory alternative that achieves the relevant objectives” unless required by law or compelling safety need. In addition, 49 CFR part 5, subpart B specifies that regulations should generally “not be issued unless their benefits are expected to exceed their costs.”

E.O. 12866 and 49 CFR part 5, subpart B also require that PHMSA submit “significant regulatory actions” to the Office of Information and Regulatory Affairs (OIRA) within the Executive Office of the President's Office of Management and Budget (OMB) for review. This final rule is not a significant regulatory action pursuant to E.O. 12866 and has not been designated as a “major rule” as defined by the Congressional Review Act (5 U.S.C. 801 et seq.).

PHMSA has complied with the requirements in E.O. 12866 as implemented by 49 CFR part 5, subpart B, and determined that this final rule will result in cost savings by reducing regulatory burdens and regulatory uncertainty for shippers of refrigerating machines by allowing for their transportation without the need for a special permit. Those cost savings may also result in reduced costs for the public to whom those entities generally transfer a portion of their compliance costs. In addition, the final rule will produce cost savings for the Federal Government, hence taxpayers, due to the reduction of special permit applications that would otherwise need to be processed by PHMSA personnel.

C. Executive Orders 14192 and 14219

PHMSA has determined that this final rule is an E.O. 14192 ( Unleashing Prosperity Through Deregulation ) deregulatory action.^[5] PHMSA finds the total costs of the rule on the regulated community will be less than zero. This final rule does not implicate any of the factors identified in section 2(a) of E.O. 14219 ( Ensuring Lawful Governance ) indicative of a regulation that is “unlawful . . .[or] that undermine[s] the national interest.” ^[6]

D. Energy-Related Executive Orders 13211, 14154, and 14156

PHMSA has analyzed this final rule in accordance with the principles and criteria contained in E.O. 14156 ( Declaring a National Energy Emergency) and E.O. 14154 ( Unleashing American Energy ).^[7] The President has declared a national emergency to address America's inadequate energy development production, transportation, refining, and generation capacity and asserted a Federal policy to unleash American energy by ensuring access to abundant supplies of reliable, affordable energy from, inter alia, the removal of “undue burden[s]” on the ( printed page 49318) identification, development, or use of domestic energy resources. PHMSA finds this final rule to be consistent with E.O. 14156 and E.O. 14154 because it will not hinder or unduly burden the transportation or production of energy or energy-related products.

In addition, this final rule is not a “significant energy action” under E.O. 13211 ( Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use ), which requires Federal agencies to prepare a Statement of Energy Effects for any “significant energy action.” ^[8] Because this final rule is not a significant action under E.O. 12866, it will not have a significant adverse effect on supply, distribution, or energy use; accordingly, OIRA has not designated this final rule as a significant energy action.

E. Executive Order 13132: Federalism

PHMSA analyzed this final rule in accordance with the principles and criteria contained in E.O. 13132 ( Federalism) and the Presidential Memorandum ( Preemption) published in the Federal Register on May 22, 2009.^[9] E.O. 13132 requires agencies to assure meaningful and timely input by State and local officials in the development of regulatory policies that may have “substantial direct effects on the States, on the relationship between the National Government and the States, or on the distribution of power and responsibilities among the various levels of government.” The Federal Hazardous Materials Transportation laws contain an express preemption provision at 49 U.S.C. 5125(b) that preempts State, local, and Tribal requirements on certain covered subjects, unless the non-Federal requirements are “substantively the same” as the Federal requirements, including the following:

(1) The designation, description, and classification of hazardous material;

(2) The packing, repacking, handling, labeling, marking, and placarding of hazardous material;

(3) The preparation, execution, and use of shipping documents related to hazardous material and requirements related to the number, contents, and placement of those documents;

(4) The written notification, recording, and reporting of the unintentional release in transportation of hazardous material; and

(5) The design, manufacture, fabrication, inspection, marking, maintenance, recondition, repair, or testing of a packaging or container represented, marked, certified, or sold as qualified for use in transporting hazardous material in commerce.

This final rule addresses a covered subject listed in Paragraph (1) above and would preempt State, local, and Tribal requirements not meeting the “substantively the same” standard. Though the final rule may operate to preempt some State requirements, it would not impose any regulation that has substantial direct effects on the States, the relationship between the National Government and the States, or the distribution of power and responsibilities among the various levels of government. The preemptive effect of the regulatory amendments in this final rule is limited to the minimum level necessary to achieve the objectives of the Federal Hazardous Materials Transportation Laws. Therefore, the consultation and funding requirements of E.O. 13132 do not apply.

F. Regulatory Flexibility Act

The Regulatory Flexibility Act (5 U.S.C. 601 et seq.) requires Federal agencies to conduct a Final Regulatory Flexibility Analysis (FRFA) for a final rule that has been subject to notice-and-comment rulemaking under the APA unless the agency head certifies that the final rule in the rulemaking will not have a significant economic impact on a substantial number of small entities. E.O. 13272 ( Proper Consideration of Small Entities in Agency Rulemaking ) obliges agencies to establish procedures promoting compliance with the Regulatory Flexibility Act.^[10] DOT posts information on a dedicated web page to help small businesses understand and navigate Federal regulatory processes.^[11] PHMSA developed this final rule in accordance with E.O. 13272 and DOT implementing guidance to ensure compliance with the Regulatory Flexibility Act. Because the final rule is expected to reduce burdens, PHMSA certifies that it does not have a significant impact on a substantial number of small entities.

G. Unfunded Mandates Reform Act of 1995

The Unfunded Mandates Reform Act (UMRA, 2 U.S.C. 1501 et seq.) requires agencies to assess the effects of Federal regulatory actions on State, local, and Tribal governments, and the private sector. For any proposed or final rule that includes a Federal mandate that may result in the expenditure by State, local, and Tribal governments, in the aggregate of $100 million or more (in 1996 dollars) in any given year, the agency must prepare, among other things, a written statement that qualitatively and quantitatively assesses the costs and benefits of the Federal mandate.

This final rule does not impose unfunded mandates under UMRA because it does not result in costs of $100 million or more (in 1996 dollars) per year for either State, local, or Tribal governments, or to the private sector.

H. National Environmental Policy Act

PHMSA has analyzed this rule pursuant to the National Environmental Policy Act (NEPA; 42 U.S.C. 4321 et seq.) and has determined it is categorically excluded under 23 CFR 771.117(c)(20), which applies to the promulgation of rules, regulations, and directives. Under Section 9 of DOT Order 5610.1D, PHMSA may apply a categorical exclusion (CE) established in another Operating Administration's procedures. PHMSA followed the requirements outlined in DOT Order 5610.1D to apply the Federal Highway Administration's CE to this deregulatory action. PHMSA has determined no unusual circumstances are present under 23 CFR 771.117(b). PHMSA's Categorical Exclusion Determination memo for this action is available on PHMSA's website.^[12]

I. Executive Order 13175

PHMSA analyzed this final rule according to the principles and criteria in E.O. 13175 ( Consultation and Coordination with Indian Tribal Governments) and DOT Order 5301.1A ( Department of Transportation Tribal Consultation Policies and Procedures ).^[13] E.O. 13175 requires agencies to assure meaningful and timely input from Tribal government representatives in the development of rules that significantly or uniquely affect Tribal communities by imposing “substantial direct compliance costs” or “substantial direct effects” on such communities or the relationship or distribution of power between the Federal government and Tribes.

PHMSA assessed the impact of the final rule and determined that it will not significantly or uniquely affect Tribal communities or Indian Tribal governments. The rulemaking's ( printed page 49319) regulatory amendments have a broad, national scope; therefore, this final rule will not significantly or uniquely affect Tribal communities, much less impose substantial compliance costs on Tribal governments or mandate Tribal action. For these reasons, PHMSA has concluded the funding and consultation requirements of E.O. 13175 and DOT Order 5301.1A do not apply.

J. Paperwork Reduction Act

The Paperwork Reduction Act (44 U.S.C. 3501 et seq.) and its implementing regulations at 5 CFR 1320.8(d) require that PHMSA provide interested members of the public and affected agencies with an opportunity to comment on information collection and recordkeeping requests. This rulemaking will not create, amend, or rescind any existing information collections. However, this rulemaking eliminates the need for persons to renew a special permit, resulting in a decrease in paperwork burden for special permit holders. PHMSA estimates the reduction in information collection burden as follows:

OMB Control No. 2137-0051: Rulemaking, Special Permits, and Preemption Requirements.

Decrease in Annual Number of Respondents: 10.

Decrease in Annual Responses: 10.

Decrease in Annual Burden Hours: 14.

Decrease in Annual Burden Cost: $0.

Please direct your requests for a copy of this information collection to Steven Andrews, Office of Hazardous Materials Standards (PHH-12), Pipeline and Hazardous Materials Safety Administration, 1200 New Jersey Avenue SE, 2nd Floor, Washington, DC 20590-0001.

K. Executive Order 13609 and International Trade Analysis

E.O. 13609 ( Promoting International Regulatory Cooperation ) requires agencies to consider whether the impacts associated with significant variations between domestic and international regulatory approaches are unnecessary or may impair the ability of American businesses to export and compete internationally.^[14] In meeting shared challenges involving health, safety, labor, security, environmental, and other issues, international regulatory cooperation can identify approaches that are at least as protective as those that are or would be adopted in the absence of such cooperation. International regulatory cooperation can also reduce, eliminate, or prevent unnecessary differences in regulatory requirements.

Similarly, the Trade Agreements Act of 1979 (Pub. L. 96-39), as amended by the Uruguay Round Agreements Act (Pub. L. 103-465), prohibits Federal agencies from establishing any standards or engaging in related activities that create unnecessary obstacles to the foreign commerce of the United States. For purposes of these requirements, Federal agencies may participate in the establishment of international standards, so long as the standards have a legitimate domestic objective, such as providing for safety, and do not operate to exclude imports that meet this objective. The statute also requires consideration of international standards and, where appropriate, that they be the basis for U.S. standards.

PHMSA engages with international standards setting bodies to protect the safety of the American public. PHMSA has assessed the effects of the final rule and has determined that its regulatory amendments will not cause unnecessary obstacles to foreign trade.

L. Cybersecurity and Executive Order 14028

E.O. 14028 ( Improving the Nation's Cybersecurity ) directed the Federal Government to improve its efforts to identify, to deter, and to respond to “persistent and increasingly sophisticated malicious cyber campaigns.” ^[15] PHMSA has considered the effects of the final rule and has determined that its regulatory amendments would not materially affect the cybersecurity risk profile for affected entities.

M. Privacy Act Statement

In accordance with 5 U.S.C. 553(c), DOT solicits comments from the public to inform its rulemaking process better. 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 https://www.dot.gov/​privacy. DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000, or on DOT's website at https://www.dot.gov/​privacy.

N. National Technology Transfer and Advancement Act

The National Technology Transfer and Advancement Act of 1995 (15 U.S.C. 272 note) directs Federal agencies to use voluntary consensus standards in their regulatory activities unless doing so would be inconsistent with applicable law or otherwise impractical. Voluntary consensus standards are technical standards ( e.g., specification of materials, test methods, or performance requirements) that are developed or adopted by voluntary consensus standard bodies. This rulemaking involves a voluntary consensus standard.

In consideration of the foregoing, PHMSA amends 49 CFR Chapter I as follows: