Phasedown of Hydrofluorocarbons: Reconsideration of Certain Regulatory Requirements Promulgated Under the Technology Transitions Provisions of the American Innovation and Manufacturing Act of 2020

A. Executive Summary

B. Does this action apply to me? II. Statutory Background and Regulatory History

A. What is the authority for this action?

B. Severability

C. Summary of 2023 Final Rule

D. Summary of 2023 Interim Final Rule

E. Summary of Administrative Petitions and Requests Related to This Rulemaking

F. Judicial Review and Administrative Review III. Summary of Final Action

A. Refrigerated Transport--Intermodal Containers

B. Industrial Process Refrigeration and Chillers for Industrial Process Refrigeration in Semiconductor Manufacturing

C. Retail Food--Supermarkets

D. Retail Food--Remote Condensing Units

E. Cold Storage Warehouses

F. Replacement Condensing Units in the Residential and Light Commercial Air Conditioning and Heat Pump Subsector

G. Industrial Process Refrigeration in Certain Laboratory Equipment

H. Preventing Stranded Inventory of Residential and Light Commercial Air Conditioning and Heat Pump Equipment

I. Labeling Correction

J. Effective Date of Rules Under Paragraph (i)(6) IV. Comments and Responses

A. Refrigerated Transport--Intermodal Containers

B. Industrial Process Refrigeration and Chillers for Industrial Process Refrigeration in Semiconductor Manufacturing

C. Retail Food--Supermarkets

D. Retail Food--Remote Condensing Units

E. Cold Storage Warehouses

F. Replacement Condensing Units in the Residential and Light Commercial Air Conditioning and Heat Pump Subsector

G. Industrial Process Refrigeration in Certain Laboratory Equipment

H. Preventing Stranded Inventory of Residential and Light Commercial Air Conditioning and Heat Pump Equipment

I. Labeling Correction

J. Effective Date of Rules Under Paragraph (i)(6)

K. Other Comments and Responses V. How do these final amendments impact the implementation of the Technology Transitions Provisions? VI. Statutory and Executive Order Reviews

A. Executive Order 12866: Regulatory Planning and Review and Executive Order 13563: Improving Regulation and Regulatory Review

B. Executive Order 14192: Unleashing Prosperity Through Deregulation

C. Paperwork Reduction Act (PRA)

D. Regulatory Flexibility Act (RFA)

E. Unfunded Mandates Reform Act (UMRA)

F. Executive Order 13132: Federalism

G. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments

H. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks

I. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use

J. National Technology Transfer and Advancement Act (NTTAA)

K. Congressional Review Act (CRA)

Subsection (i) of the AIM Act provides that the Administrator “may by rule restrict, fully, partially, or on a graduated schedule, the use of a regulated substance \2\ in the sector or subsector in which the regulated substance is used.” \3\ The EPA may exercise this discretionary authority either on its own initiative or in response to petitions for a restriction on the use of one or more regulated substance(s). In deciding whether and how to exercise this authority, the EPA must consider the best available data, the availability of substitutes (including technological achievability, commercial demand, affordability for consumers, safety, and other relevant factors), overall economic costs and environmental impacts as compared to historical trends, and the remaining phasedown period for the regulated substance(s), if applicable.\4\

\2\ “Regulated substance” and “HFC” are used interchangeably in this rule. The AIM Act defines “regulated substance” by reference to a list of HFCs and the EPA has not attempted to add any additional saturated hydrofluorocarbons to the statutory list pursuant to subsection (c)(3). See 42 U.S.C. 7675(c)(1), (c)(2)(A).

\3\ See 42 U.S.C. 7675(i)(1).

\4\ See 42 U.S.C. 7675(i)(4)-(5).

On October 24, 2023, the EPA published a final rule under subsection (i) of the AIM Act entitled “Phasedown of Hydrofluorocarbons: Restrictions on the Use of Certain Hydrofluorocarbons Under the American Innovation and Manufacturing Act of 2020” (2023 Final Rule).\5\ This final rule restricted the use of HFCs in specific sectors or subsectors, established a process for submitting technology transitions petitions, established recordkeeping and reporting requirements, and addressed certain other elements related to the effective implementation of the AIM Act. The 2023 Final Rule became effective on December 26, 2023. The 2023 Final Rule applied to over 40 subsectors across the aerosols, foams, and refrigeration, air conditioning, and heat pumps sectors.

\5\ See 88 FR 73098 (October 24, 2023).

After publication of the 2023 Final Rule, manufacturers, importers, and distributors of residential and light commercial air conditioning and heat pump equipment informed the EPA that the compliance date for the restriction on installation will result in substantial stranded inventory in that subsector for residential new construction, including both single-family and multi-family dwellings, where builders order heating and cooling equipment well in advance of knowing the exact date of installation. In response, the EPA issued an interim final rule (IFR) \6\ to address the unique circumstances of that particular subsector to prevent such equipment from being stranded.

\6\ See 88 FR 88825 (December 26, 2023).

The EPA also received four administrative petitions for reconsideration and several requests to adjust certain provisions of the 2023 Final Rule after its publication.

On January 31, 2025, the President issued Executive Order 14192 (Unleashing Prosperity through Deregulation).\7\ On March 12, 2025, against this backdrop, the EPA announced plans for deregulatory actions to, among other things, lower the cost of living for American families.\8\ On that same day, and as part of the larger Agency plan, the EPA announced plans to reconsider the regulations promulgated via the 2023 Final Rule “that forces companies to use certain technologies that increased costs on food at grocery stores and semiconductor manufacturing.” \9\

\7\ See 90 FR 9065 (February 6, 2025).

\8\ See EPA Launches Biggest Deregulatory Action in U.S. History, March 12, 2025, in the docket for this action.

\9\ See Trump EPA Announces OOOO b/c Reconsideration of Biden- Harris Rules Strangling American Energy Producers, March 12, 2025, in the docket for this action.

On October 3, 2025, the EPA published a notice of proposed rulemaking entitled “Phasedown of Hydrofluorocarbons: Reconsideration of Certain Regulatory Requirements Promulgated Under the Technology Transitions Provisions of the American Innovation and Manufacturing Act of 2020” (October 2025 Proposal) \10\ that proposed revisions for restrictions applicable to: certain intermodal refrigerated transport containers, certain

industrial process refrigeration and chillers for industrial process refrigeration equipment used in semiconductor manufacturing, retail food--supermarket systems, retail food--remote condensing units, cold storage warehouses, residential and light commercial air conditioning and heat pump systems, and certain laboratory equipment, among other provisions.

\10\ See 90 FR 47999 (October 3, 2025).

This final rule addresses significant issues raised in administrative petitions and input received from regulated industry and other interested parties with respect to regulatory provisions promulgated in the Code of Federal Regulations (CFR) pursuant to the AIM Act subsection (i). In particular, the EPA received four administrative petitions \11\ to reconsider certain provisions of 40 CFR part 84, subpart B, entitled “Restrictions on the Use of Hydrofluorocarbons,” that were finalized in the 2023 Final Rule. We also received other requests to reassess compliance dates and/or other provisions finalized in the 2023 Final Rule. Specifically, this final rule:

\11\ See administrative petitions for reconsideration in the docket for this action.

1. Amends the intermodal refrigerated transport provisions at 40 CFR 84.54(a)(6) and 84.54(c)(7) to: (a) adjust the lower bound temperature exclusion threshold of -50 [deg]C to -35 [deg]C, and (b) change the location where that temperature is measured.

2. Amends the compliance date for certain chillers used for industrial process refrigeration (IPR) and certain IPR equipment used to manufacture semiconductors from January 1, 2026, and January 1, 2028, as applicable, to January 1, 2030.

3. Amends the global warming potential (GWP) limit (hereafter “limit”) for retail food remote condensing units at 40 CFR 84.54(c)(11) from 150 or 300, as applicable, to 1,400 until January 1, 2032, and either 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032.

4. Amends the limit for supermarket systems at 40 CFR 84.54(c)(12) from 150 or 300, as applicable, to 1,400 until January 1, 2032, and either 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032.

5. Amends 40 CFR 84.54(e)(2) to allow supermarket systems to increase system cooling capacity up to 15 percent from zero percent compared to original installed capacity without this being considered the installation of a new system.

6. Amends the limit for cold storage warehouses at 40 CFR 84.54(c)(9) from 150 or 300, as applicable, to 700 until January 1, 2032, and either 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032.

7. Amends the compliance date for refrigerated laboratory centrifuges and laboratory shakers from January 1, 2026, to January 1, 2028.

8. Removes the installation deadline for systems in the residential and light commercial air conditioning and heat pumps (AC/HP) subsector, where all specified components of such systems were domestically manufactured or imported before January 1, 2025.

9. Corrects a typographical error at 40 CFR 84.58(b). 3. Impacts From This Rule

Table 1 of this preamble below provides a summary of both monetized and non-monetized impacts. Monetized impacts include estimated engineering cost savings for equipment owners in affected subsectors. These cost savings arise from cases where additional flexibility provided by the rule allows for the use of refrigerant-containing equipment with lower capital and/or operating costs than equipment that would otherwise likely be chosen without additional flexibility. As part of fulfilling analytical guidance with respect to Executive Order 12866, the EPA presents estimates of the present value (PV) of the benefits and costs over the full time series included in this analysis (2026-2050). To calculate the PV of the cost savings of the rule, annual savings are discounted to 2025 at three percent and seven percent discount rates as directed by Office of Management and Budget (OMB) Circular A-4. The EPA also presents the equivalent annualized value (EAV), which represents a flow of constant annual values that, had they occurred in each year in the time series, would yield a sum equivalent to the PV, discounted at three percent and seven percent.

Table 1--Summary of Monetized and Non-Monetized Economic Impacts, 2026-2050

[Millions of 2024 dollars]

Monetized Impacts

Engineering Cost Savings in Affected Subsectors. 3 Percent discount rate

7 Percent discount rate

PV EAV PV EAV

$976 $56 $653 $56

Non-Monetized Impacts

Benefits and Cost Savings:

Avoided loss of ability to produce semiconductor wafers within the United States...................

National security benefits......................................................................... Costs and Forgone Benefits:

Indirect costs via HFC market impacts..............................................................

Costs to equipment manufacturers and suppliers related to incremental investments required.........

Forgone benefits from potential increased emissions of HFCs........................................

The EPA anticipates that this action will result in indirect market and/or distributional consumer effects not explicitly included in the monetized impacts. For example, as supermarkets operate with extremely thin margins (1-

2%), supermarkets are not able to internalize additional regulatory costs much and externalize those costs on customers, thereby driving up costs of food and other goods. Therefore, we expect that almost all, if not all, of the cost savings for supermarkets will be passed onto customers, thus reducing the burden of AIM Act implementation under subsection (i) on consumers in the form of increased prices for food and other goods.

There are economic effects with potentially significant consequences related to other provisions as well, including for semiconductor manufacturing. For example, under the baseline requirements, semiconductor facilities using IPR or Chillers for IPR equipment with charge sizes of 100 pounds or less faced technically infeasible requirements. Such facilities would have been forced to delay operations or invest in costly pre-commercial technologies. To the extent productivity may have been impacted, the costs could have been significantly larger than the costs of refrigeration equipment.\12\

\12\ Comment from Semiconductor Equipment and Materials International (SEMI): “The economic costs of downtime in semiconductor production are extraordinary. A modern fabrication plant can lose millions of dollars per day in halted output.” See Docket ID No. EPA-HQ-OAR-2025-0005-0051.

In addition, this action may result in increased demand for HFCs. This in turn may result in tighter supply \13\ and higher HFC prices for downstream consumers, including users of HFCs in subsectors outside the scope of this final rule. In combination with other AIM Act rules, the adjustments in this action can continue to support an efficient transition from HFCs to lower-GWP alternatives, consistent with the statutory requirements under the AIM Act.

\13\ Overall supply of HFCs is constrained by the statutory HFC phasedown caps contained in subsection (e) of the AIM Act.

For more detailed information, see the memorandum entitled Analysis of Economic and Environmental Impacts--Phasedown of Hydrofluorocarbons: Reconsideration of Certain Regulatory Requirements Promulgated Under the Technology Transitions Provisions of the American Innovation and Manufacturing Act of 2020 (“Economic and Environmental Impacts Memo”). The information provided in the Economic and Environmental Impacts Memo and in this section of the preamble is descriptive and for informational purposes only; it is not part of the rationale for reaching the decisions in this final rule. The EPA is not relying on this section or the Economic and Environmental Impacts Memo as a record basis for the final action.

You may be potentially affected by this rule if you manufacture, import, export, sell, distribute, install, or use refrigerated transport intermodal containers, chillers and industrial process refrigeration equipment used in the manufacture of semiconductors, retail food refrigeration equipment for remote condensing units and supermarkets, refrigeration systems in cold storage warehouses, refrigerated centrifuges, refrigerated laboratory shakers, or residential and light commercial air-conditioning and heat pump systems. Potentially affected categories, by North American Industry Classification System (NAICS) code, are:

236116; New Multifamily Housing Construction (except For-Sale Builders)

236117; New Housing For-Sale Builders

236118; Residential Remodelers

236210; Industrial Building Construction

236220; Commercial and Institutional Building Construction

238220; Plumbing, Heating, and Air Conditioning Contractors

325120; Industrial Gas Manufacturing

333242; Semiconductor Machinery Manufacturing

333415; Air Conditioning and Warm Air Heating Equipment and Commercial and Industrial Refrigeration Equipment Manufacturing

333998; All Other Miscellaneous General Purpose Machinery Manufacturing

334413; Semiconductor and Related Device Manufacturing

335220; Major Household Appliance Manufacturing

423620; Household Appliances, Electric Housewares, and Consumer Electronics Merchant Wholesalers

423720; Plumbing and Heating Equipment and Supplies (Hydronics) Merchant Wholesalers

423730; Warm Air Heating and Air Conditioning Equipment and Supplies Merchant Wholesalers

423740; Refrigeration Equipment and Supplies Merchant Wholesalers

424410; General Line Grocery Merchant Wholesalers

424420; Packaged Frozen Food Merchant Wholesalers

445110; Supermarkets and Other Grocery (except Convenience) Stores

445131; Convenience Retailers

449210; Electronics and Appliance Retailers

452311; Warehouse Clubs and Supercenters

483111; Deep Sea Freight Transportation

484230; Specialized Freight (Except Used Goods) Trucking, Long-Distance

493120; Refrigerated Warehousing Storage

531110; Lessors of Residential Buildings and Dwellings

531120; Lessors of Nonresidential Buildings (except Miniwarehouses)

541380; Testing Laboratories

561210; Facilities Support Services

811412; Appliance Repair and Maintenance

This list is not intended to be exhaustive but rather provides a guide for readers regarding entities likely to be regulated by this action. This list includes the types of entities that the EPA is now aware could potentially be regulated by this action. Other types of entities not listed could also be regulated. To determine whether your entity may be regulated by this action, you should carefully examine the applicability criteria found in the regulatory text at the end of this document. If you have questions regarding the applicability of this action to a particular entity, consult the person listed in the FOR FURTHER INFORMATION CONTACT section.

The AIM Act authorizes the EPA to regulate HFCs in three main areas: phasing down the production and consumption of listed HFCs; management of these HFCs and their substitutes; and facilitating the transition to next-generation technologies by restricting use of these HFCs in the sector or subsectors in which they are used. This rule focuses on the third area: the transition to next-generation technologies.

Subsection (i) of the AIM Act, titled “Technology Transitions,” provides that “the Administrator may by rule restrict, fully, partially, or on a graduated schedule, the use of a regulated substance in the sector or subsector in which the regulated substance is used.” \14\ Unlike other provisions in the AIM Act, the Administrator's subsection (i) authority is discretionary. When deciding whether and how to exercise this discretionary authority, the EPA “shall, to the extent practicable, factor in” several enumerated considerations, including use of “the best available data,” “the availability of substitutes for

use of the regulated substance that is the subject of the rulemaking or petition, as applicable, in a sector or subsector, taking into account technological achievability, commercial demands, affordability for residential and small business consumers, safety, consumer costs, building codes, appliance efficiency standards, contractor training costs, and other relevant factors, including the quantities of regulated substances available from reclaiming, prior production, or prior import,” “overall economic costs and environmental impacts, as compared to historical trends,” and “the remaining phase-down period for regulated substances” under applicable regulations.\15\ In this way, Congress expressly required the EPA to consider the cost of subsection (i) rules, including costs to consumers, as well as additional factors like technical feasibility, and authorized the Agency to consider “other relevant factors” pertaining to the availability of substitutes. For additional discussion of the EPA's authorities under subsection (i) of the AIM Act, please refer to the 2023 Final Rule.\16\

\14\ See 42 U.S.C. 7675(i)(1).

\15\ See 42 U.S.C. 7675(i)(4)(A)-(D); see also id. 7675(i)(5) (“In carrying out this subsection, the Administrator shall--(A) evaluate substitutes for regulated substances in a sector or subsector, taking into account technological achievability, commercial demands, safety, overall economic costs and environmental impacts, and other relevant factors; and (B) make the evaluation under subparagraph (A) available to the public, including the factors associated with the safety of those substitutes.”).

\16\ See 88 FR 73098 (October 24, 2023).

In addition, subsection (k)(1)(A) of the AIM Act authorizes the EPA to promulgate such regulations as are necessary to carry out the AIM Act's functions, including its obligations to ensure that requirements of the AIM Act are satisfied.\17\ Subsection (k)(1)(C) of the AIM Act further provides that CAA sections 113, 114, 304, and 307 apply to the AIM Act and any regulations promulgated thereunder as though the AIM Act were part of title VI of the CAA.\18\ Accordingly, this rulemaking is subject to the procedural requirements of CAA section 307(d).\19\

\17\ See 42 U.S.C. 7675(k)(1)(A).

\18\ See 42 U.S.C. 7675(k)(1)(C).

\19\ See 42 U.S.C. 7607(d)(1)(I).

The EPA noted in the preamble to the proposed rule that this rulemaking does not merit the use of negotiated rulemaking procedures described in paragraph (i)(2). The EPA received no comments on this issue and is not revisiting it in this final rule.

Unless provided otherwise by statute, an agency may revise or rescind prior actions so long as it acknowledges the change in position, provides a reasonable explanation for the new position, and considers legitimate reliance interests in the prior position.\20\ Relevant case law confirms that legitimate reliance interests do not create a higher bar for adopting a new policy but rather serve as relevant considerations along with other relevant factors informing the new policy.\21\

\20\ See FDA v. Wages & White Lion Invs., LLC, 145 S. Ct. 898 (2025); FCC v. Fox TV Stations, Inc., 556 U.S. 502 (2009); Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins. Co., 463 U.S. 29 (1983); Clean Air Council v. Pruitt, 862 F.3d 1, 8 (D.C. Cir. 2017) (“Agencies obviously have broad discretion to reconsider a regulation at any time.”).

\21\ DHS v. Regents of Univ. of Cal., 591 U.S. 1, 21 (2020) (“Agencies are not compelled to explore every alternative device and thought conceivable by the mind of man. But, because DHS was not writing on a blank slate, it was required to assess whether there were reliance interests, determine whether they were significant, and weigh any such interests against competing policy concerns.”) (internal citations omitted); MediNatura, Inc. v. FDA, 998 F.3d 931, 942-43 (D.C. Cir. 2021) (in withdrawing a 30-year old guidance document on enforcement of homeopathic drugs, FDA considered reliance interests and reasonably explained that the new policy was supported by safety concerns, the continued expansion in the impacted industry, and the agency's general interest in its risk- based enforcement approach).

The EPA has considered the reliance interests presented to the Agency in this rulemaking in the comments and elsewhere. Here, the Agency has considered the reliance interests detailed in the comments along with other considerations, including the AIM Act's subsection (i)(4) statutory factors, and has determined that the requirements should be amended as is detailed in this rulemaking. The EPA received specific comments on reliance interests relating to the retail food-- supermarkets, retail food--remote condensing units, and cold storage warehouses subsectors. For particular responses to those comments, see section IV.K.2 of this preamble.

In the 2023 Final Rule, the EPA considered a number of petitions submitted under subsection (i)(3) to restrict, fully, partially, or on a graduated schedule, the use of HFCs in the sector or subsector in which the regulated substance is used.\22\ The Agency's analysis supporting that final rule endeavored to apply the factors in subsection (i)(4) of the AIM Act to the information available to the EPA at that time, including with respect to availability of substitutes, overall economic costs and environmental impacts, and the remaining phasedown period for HFCs. Among other things, the 2023 Final Rule prohibited the domestic manufacture and import of aerosols, foams, and factory-completed refrigeration, AC, and heat pump products as well as the installation of refrigeration, AC, and heat pump systems that use HFCs or HFC blends above specified limits.

\22\ See 88 FR 73098 (October 24, 2023).

The compliance dates for these restrictions varied by sector and subsector and generally ranged from January 1, 2025, to January 1, 2028. The rule also prohibited the sale, distribution, and export of factory-completed products that do not comply with the relevant restrictions three years after the prohibition on domestic manufacture and import goes into effect. The rule did not prohibit the sale, distribution, and export of components needed to repair existing refrigeration and air conditioning systems.

To meet the compliance dates and limits for the sectors and subsectors with restrictions in the 2023 Final Rule, various degrees of change were required. The Agency based decisions for compliance dates and limits on a variety of factors, including, but not limited to: petitions submitted under AIM Act subsection (i), comments received on those petitions, information we provided in market characterization technical support documents located in the docket for the 2023 Final Rule, and comments on the proposal to the 2023 Final Rule. For example, for sectors such as aerosols and foams, alternatives

below the limits were in use, often to large degrees. Similarly, several subsectors in the refrigeration and AC sector, such as motor vehicle air conditioning, household refrigerators and freezers, retail food--refrigeration stand-alone units, and others, had alternatives below the applicable limits that were widely available and in use. Other subsectors had known alternatives with more nascent technologies such as retail food--supermarket systems. The subsectors with identified alternatives with more limited use generally had later compliance dates, such as Chiller for IPR systems and IPR systems that operate at temperatures between -50 [deg]C to -30 [deg]C. Equipment in such subsectors had compliance dates of January 1, 2028. See the 2023 Final Rule and the Regulatory Impact Analysis and other documents in that docket for additional information.

The EPA received four administrative petitions to reconsider certain aspects of the 2023 Final Rule.\24\ One petitioner requested that the EPA adjust the temperature threshold and temperature location for transport refrigeration--intermodal containers. Another requested an extension of the compliance date for process refrigeration equipment used in semiconductor manufacturing. Two separate petitioners requested that the EPA consider limiting import, domestic manufacture, and installation of condensing units used for residential and light commercial AC/HP systems. The EPA granted reconsideration of these administrative petitions in June 2024 \25\ and the October 2025 Proposal for this rulemaking provided an opportunity for public comment on a set of proposed changes based on these administrative petitions. The EPA also received other requests to adjust certain restrictions at 40 CFR part 84, subpart B for certain retail food subsectors,\26\ cold storage warehouses,\27\ refrigerated laboratory centrifuges,\28\ and laboratory shakers.\29\ In response to these requests and additional concerns identified by the Agency and stakeholders, the EPA announced a reconsideration of aspects of the 2023 Final Rule on March 12, 2025, as one of the deregulatory actions included in the Administrator's “Powering the Great American Comeback” initiative.\30\

\24\ Three petitions for judicial review of the 2023 Final Rule were also filed in the U.S. Court of Appeals for the D.C. Circuit and are being held in abeyance. See Semiconductor Equipment & Materials Int'l v. EPA (D.C. Cir. Case No. 23-1344); Chemours Co. FC, LLC v. EPA (D.C. Cir. Case No. 23-1345); and Food Marketplace, Inc. et al. v. EPA (D.C. Cir. Case No. 23-1347).

\25\ The four administrative petitions for reconsideration and the EPA's responses granting reconsideration are in the docket for this action.

\26\ See letter from trade association dated February 11, 2025, in the docket for this action.

\27\ See request from trade association dated March 6, 2025, in the docket for this action.

\28\ See request from manufacturer dated June 6, 2024, in the docket for this action.

\29\ See request from manufacturer, dated April 8, 2025, in the docket for this action.

\30\ See EPA Launches Biggest Deregulatory Action in U.S. History, March 12, 2025, in the docket for this action.

The AIM Act regulations promulgated herein may be challenged in the United States Court of Appeals for the District of Columbia Circuit. Pursuant to CAA section 307(b)(1), petitions for judicial review of the AIM Act regulations must be filed in that court within 60 days after the date notice of this final action is published in the Federal Register.

The AIM Act provides that certain sections of the CAA “shall apply” to the AIM Act and actions “promulgated by the Administrator of [EPA] pursuant to [the AIM Act] as though [the AIM Act] were expressly included in title VI of [the CAA].” \31\ Among the applicable sections of the CAA is section 307, which includes provisions on judicial review. CAA section 307(b)(1) provides, in part, that petitions for review must only be filed in the United States Court of Appeals for the District of Columbia Circuit: (i) when the agency action consists of “nationally applicable regulations promulgated, or final actions taken, by the Administrator,” or (ii) when such action is locally or regionally applicable, but “such action is based on a determination of nationwide scope or effect.” \32\

\31\ See 42 U.S.C. 7675(k)(1)(C).

\32\ See 42 U.S.C. 7607(b)(1).

The AIM Act regulations promulgated herein are “nationally applicable regulations” within the meaning of CAA section 307(b)(1). These regulations establish regulatory requirements applicable across the entire United States to implement restrictions under subsection (i) of the AIM Act. The regulations promulgated herein amend an existing nationally applicable regulation by adjusting a compliance deadline for certain systems. The deadlines in the amended regulation and the conditions required to qualify for those extended deadlines are nationally applicable to all affected entities. Accordingly, under CAA section 307(b)(1), petitions for judicial review of these AIM Act regulations must be filed in the United States Court of Appeals for the District of Columbia Circuit by July 27, 2026.

CAA section 307(d)(7)(B) further provides that “[o]nly an objection to a rule or procedure which was raised with reasonable specificity during the period for public comment (including any public hearing) may be raised during judicial review.” This section also provides a mechanism for the EPA to convene a proceeding for reconsideration “[i]f the person raising an objection can demonstrate to the EPA that it was impracticable to raise such objection within [the period for public comment] or if the grounds for such objection arose after the period for public comment, (but within the time specified for judicial review) and if such objection is of central relevance to the outcome of the rule.” \33\ Any person seeking to make such a demonstration to us should submit a Petition for Reconsideration to the Office of the Administrator, U.S. Environmental Protection Agency, Room 3000, WJC South Building, 1200 Pennsylvania Ave. NW, Washington, DC 20460, with a copy to both the person(s) listed in the preceding FOR FURTHER INFORMATION CONTACT section and the Associate General Counsel for the Air and Radiation Law Office, Office of General Counsel (Mail Code 2344A), U.S. EPA, 1200 Pennsylvania Ave. NW, Washington, DC 20460.

\33\ See 42 U.S.C. 7607(d)(7)(B).

The EPA is finalizing amendments to provisions related to refrigerated transport--intermodal containers, as proposed. Specifically, this final rule raises the lower-bound temperature exclusion threshold of -50 [deg]C to -35 [deg]C and changes the location where that temperature is measured to the inside of the container, referred to as the box temperature. 1. Background

Refrigerated transport--intermodal containers are refrigerated containers with an integrated power source that allow uninterrupted storage during transport on different mobile platforms, including railways, road trucks, and vessels.\34\ These intermodal containers used for refrigerated transport are regulated as products and systems at 40 CFR 84.54(a)(6) and (c)(7), respectively, depending on their design. They primarily carry perishable goods (e.g., food) and pharmaceuticals at temperatures between -30 [deg]C and 16 [deg]C and can be designed to operate at higher and lower temperatures.

\34\ See 88 FR 73171 (October 24, 2023).

The 2023 Final Rule restricted the use of HFCs in intermodal containers when the temperature of the refrigerant entering the evaporator (for direct heat exchange systems) or the temperature of the fluid exiting (for chillers) is -50 [deg]C or higher.\35\ These regulations do not apply where temperatures are below -50 [deg]C. At the time, the EPA understood that several substitutes were available for refrigerated transport--intermodal containers, including R-744 (also known as carbon dioxide or CO2),\36\ R-450A, R- 513A.\37\ As discussed in the October 2025 proposal, the EPA received comments on the proposal to the 2023 Final Rule, including a request for a higher limit than 700 for such equipment operating below -50 [deg]C.\38\ The EPA did not receive information at the time indicating that operating such equipment with refrigerants below a 700 limit at temperatures above -50 [deg]C and below -35 [deg]C was infeasible.

\35\ The restrictions for refrigerated transport--intermodal containers began January 1, 2025. The EPA issued a no action assurance on January 17, 2025, regarding the restrictions at 40 CFR 84.54(a)(6) and (c)(7), which remained in effect until January 1, 2026. The EPA extended the no action assurance on December 22, 2025, until September 1, 2026, or the date this rulemaking is finalized, whichever occurs earlier.

\36\ R-744 is the ASHRAE refrigerant designation for carbon dioxide (CO2).

\37\ See 88 FR 73172 (October 24, 2023).

\38\ See 90 FR 48002 (October 3, 2025).

After publication of the 2023 Final Rule, a manufacturer of intermodal containers that maintain a range of temperatures, petitioned the EPA to raise the temperature threshold and change the temperature measurement location for this subsector.\39\ The petitioner requested the regulatory text at 40 CFR 84.54(a)(6) and (c)(7) be changed to, “Effective January 1, 2025, refrigerated transport--intermodal containers designed to reach and maintain -35 [deg]C box temperature or higher using a regulated substance, or a blend containing a regulated substance, with a global warming potential of 700 or greater.” In particular, the petitioner requested that the EPA adjust the temperature threshold to distinguish between refrigerants used for deep frozen cargo and those used for fresh and frozen cargo. The petitioner noted that deep frozen cargo containers are used to transport cargo that require temperatures at or below -35 [deg]C and include critical life sciences products such as blood plasma and pharmaceuticals. The petitioner stated that intermodal containers used to transport deep frozen cargo must use refrigerants with lower boiling points, including R-404A and R-452A.\40\ This contrasts with fresh and frozen cargo containers, which the petitioner noted require temperatures that range from -30 [deg]C to 30 [deg]C, and previously could use R-134a. One compliant refrigerant that can achieve temperatures in this range, and is currently used, includes R-513A.\41\ The petitioner indicated that there are no available refrigerants below the applicable limit that can achieve and maintain box temperatures below -35 [deg]C.

\39\ See manufacturer's administrative petition for reconsideration in the docket for this action.

\40\ See email from manufacturer, dated January 16, 2025, in the docket for this action.

\41\ See materials from manufacturer submitted November 2023 in the docket for this action.

In the administrative petition, the petitioner also requested an adjustment to the location at which the temperature is measured from the “temperature of the refrigerant entering the evaporator (for direct heat exchange systems) or the temperature of the fluid exiting (for chillers)” to the “box temperature” because this measurement is more commonly used by the industry in this subsector. The box temperature is the temperature within the intermodal refrigerated transport container (i.e., the “box”). The petitioner also requested that the EPA clarify that the temperature measurement be based on the lowest temperature at which the equipment is “designed to reach and maintain.” The petitioner further explained that this subsector uses direct expansion equipment, not chillers, so the reference to chillers in the regulatory text is unnecessary.

Based on the new information from the administrative petition, the EPA agreed with the petitioner that there are currently no refrigerants available with sufficiently low boiling points and high refrigeration capacities for this temperature range. The EPA thus proposed to raise the temperature threshold for this equipment from -50 [deg]C to -35 [deg]C. The EPA also agreed with the petitioner that the location at which the temperature is measured is better suited as the box temperature. The EPA thus also proposed to adjust the location at which the temperature is measured to be the box temperature.\42\

\42\ See 90 FR 47999 (October 3, 2025).

The EPA is amending the provisions related to refrigerated transport--intermodal containers as proposed. The EPA evaluated the additional information provided by the petitioner \43\ after publication of the 2023 Final Rule, the comments provided on the proposed rule, and other information, and reassessed the factors under AIM Act subsection (i)(4). The Agency concludes that refrigerants used to reach and maintain such low temperatures in intermodal containers require refrigerants with sufficiently low boiling points and high refrigeration capacities.\44\ Among other rationale provided within this section, section IV.A of this preamble, and in the Response to Comments document, the Agency finds that there is no alternative that is currently available that meets the limit established in the 2023 Final Rule and which could meet the needs of intermodal refrigerated transport equipment designed to operate at box temperatures below -35 [deg]C. Given the transportation conditions necessary for shipping blood plasma, pharmaceuticals, temperature-sensitive enzymes, dangerous goods, and other materials at temperatures below -35 [deg]C, the EPA concludes that targeted relief is appropriate and consistent with the factors and considerations set out in AIM Act subsection (i)(4) given the change in our understanding of availability of substitutes for this temperature range for this equipment. The Agency describes and responds to

comments in section IV.A of this preamble and the Response to Comments document in the docket.

\43\ See materials from manufacturer submitted November 2023 in the docket for this action.

\44\ See table of refrigerants (R-404A, R-452A, R-513A, R-450A, R-744), their boiling points, and refrigeration capacities in the docket for this action.

The EPA is finalizing amendments to provisions related to IPR and Chillers for IPR used to manufacture semiconductors as proposed. Specifically, the EPA is extending the compliance date for certain IPR and Chillers for IPR. The compliance date is extended from January 1, 2026, and January 1, 2028, as applicable, to January 1, 2030. This extension is limited to equipment used in semiconductor manufacturing that has a charge size of 100 pounds or less. 1. Background

The EPA considers refrigeration equipment used in semiconductor manufacturing to fall within the IPR and Chillers for IPR subsectors.\45\ The refrigeration equipment is often built into specialized machines that sort, mark, and cut wafers during the semiconductor manufacturing process, referred to as “Semiconductor Manufacturing and Related Equipment,” or SMRE, throughout this rule. SMRE may operate at a range of temperatures depending on the function being performed and typically must maintain precise temperatures to produce high-quality semiconductor wafers.

\45\ See 88 FR 73119 (October 24, 2023).

IPR systems are used to cool process streams at a specific point in manufacturing and other industrial processes (e.g., in the chemical, pharmaceutical, and petrochemical industries). IPR systems are directly linked to the industrial process, meaning the refrigerant leaving the condenser and metering device is delivered directly to the heat source before returning to the compressor.\46\

\46\ See 88 FR 73141-42.

A chiller is a type of equipment that uses refrigerant to cool water or a brine solution that is then pumped to fan coil units or other air handlers to cool the air that is supplied to the conditioned spaces. The heat absorbed by the water or brine can be used for heating purposes and/or transferred directly to the air (“air-cooled”), to a cooling tower or body of water (“water-cooled”), or through evaporative coolers (“evaporative-cooled”).\47\ Chillers can be used to cool process streams in industrial applications; in such instances, these chillers are regulated as “Chillers for IPR” and not as “IPR.” Throughout this rule, the term “IPR” refers to IPR equipment that does not use chillers. The term “Chillers for IPR” refers to IPR equipment that utilizes chillers.

\47\ See 88 FR 73174.

Restrictions on the use of HFCs and HFC blends in IPR and Chillers for IPR, including process equipment used to manufacture semiconductors, are implemented at different limits (150, 300, and 700). The restrictions put in place by the 2023 Final Rule start on either January 1, 2026, or January 1, 2028, depending on charge size and the temperature at which the equipment is designed to operate.\48\ IPR and Chillers used for IPR at temperatures below -50 [deg]C are not subject to restrictions under the 2023 Final Rule.

\48\ The EPA issued a no action assurance on December 22, 2025, for this equipment that lasts until September 1, 2026, or until this rule is finalized, whichever comes sooner.

A trade association representing the semiconductor industry petitioned the EPA on December 22, 2023, to reconsider the compliance dates that affect SMRE for the IPR and Chillers for IPR subsectors. The petitioner submitted multiple supplemental letters to the Agency in the following months clarifying requests in their administrative petition. In one letter, they clarified that the administrative petition seeks relief only for SMRE that have a charge size of 100 pounds or less. They also clarified that for the relevant restrictions with compliance dates of January 1, 2026, or January 1, 2028, they request delaying the compliance date to January 1, 2030.\49\ Five SMRE suppliers also submitted letters to the Agency between May 2024 and August 2024 indicating their support of the trade association's request to extend the relevant compliance dates to January 1, 2030.\50\

\49\ See semiconductor trade association's letter to the EPA, dated May 3, 2024, in the docket for this action.

\50\ See letters of support from five semiconductor equipment manufacturing suppliers in the docket for this action.

The petitioner stated that equipment using substitute refrigerants that fit this industry's unique circumstances will not be available by the current compliance dates and estimated that developing and implementing alternatives that are fit for purpose could take five years.\51\ In particular, the petitioner noted that to manufacture semiconductors, process refrigeration equipment must be able to maintain precise control of narrow temperature tolerances, which can be as small as 0.1 [deg]C 0.05 [deg]C for some applications. The petitioner also explained that using certain substitutes such as CO2 or lower flammability and flammable alternatives as a refrigerant in SMRE would require changing how equipment is integrated into semiconductor manufacturing facilities or limit the capabilities of the process equipment.

\51\ See semiconductor trade association's supplemental submission to the EPA, dated June 18, 2024, in the docket for this action.

The petitioner stated that CO2 offers a potential path, yet some challenges would require further validation and testing.\52\ The petitioner has indicated that although R-728 \53\ may also be a viable refrigerant, it would not be tested and validated in time to meet the compliance dates established in the 2023 Final Rule.\54\ The petitioner also indicated that R-32 and R-454C are not immediately viable solutions because they both are flammable and R-32 would not meet the limit for all SMRE use cases.

\52\ See semiconductor trade association's supplemental submission to the EPA, dated June 18, 2024, in the docket for this action.

\53\ R-728 is the ASHRAE refrigerant designation for nitrogen gas (N2).

\54\ See February 20, 2024, meeting between semiconductor trade association and the EPA in the docket for this action.

The petitioner noted that SMRE are custom-engineered and that equipment availability is limited to meet the precise temperature and humidity control requirements, particularly in the range between -50 [deg]C and -30 [deg]C. Due to the combination of factors that present unique circumstances for this industry, the petitioner asserted that the development of substitutes for SMRE will take more time than for IPR and Chillers for IPR used in other sectors.\55\ Further details are found in the proposed rule for this action.

\55\ See semiconductor trade association's letter to the EPA, dated May 3, 2024, in the docket for this action.

The EPA agreed with the petitioner on the time needed to design, test, qualify, validate, and deploy substitutes for SMRE with charge sizes of 100 pounds or less. The EPA also agreed that a compliance deadline of January 1, 2030, for this equipment, as suggested by the petitioner and five semiconductor equipment manufacturing suppliers, is reasonable for available substitutes to be developed. The EPA therefore proposed to extend the compliance date for IPR and Chillers for IPR equipment used in semiconductor manufacturing which have a charge size of 100 pounds or less from January 1, 2026, and January 1, 2028, as applicable, to January 1, 2030. 2. Final Rule

The EPA is finalizing provisions related to IPR and Chillers for IPR used to manufacture semiconductors as

proposed. Specifically, the EPA is delaying the compliance dates for certain IPR and Chillers for IPR from January 1, 2026, and January 1, 2028, as applicable, to January 1, 2030. This extension is limited to equipment used in semiconductor manufacturing that has a charge size of 100 pounds or less.

Given the additional information the Agency received since the 2023 Final Rule, the Agency has reassessed the factors under subsection AIM Act subsection (i)(4). The EPA finds that the semiconductor manufacturing industry faces unique circumstances in manufacturing semiconductors, including ensuring that available substitutes can satisfy precise temperature control requirements. For example, the petitioner explained that precise control is required to realize process performance, including a uniform application of photoresist coatings. They noted that small changes in temperature during production can impact semiconductor device features, product functionality, and product yields. As a further example, the petitioner described how a 1 [deg]C change in temperature in a projection lens can result in a few microns accuracy loss and would be “catastrophic” \56\ for semiconductor production. The EPA reviewed the comments and information provided by industry, including letters submitted by five semiconductor manufacturing equipment suppliers,\57\ that provided additional details on the time needed to test and validate alternatives. The EPA agrees with semiconductor manufacturers' concerns, particularly for potential downtime and that such downtime could have impacts on critical industries and national security. An inability to acquire compliant technology could disrupt semiconductor manufacturing output, which could lead to supply chain disruptions, with global repercussions in the form of shortages and price volatility. These supply chain disruptions could cascade across industries dependent on advanced semiconductor chips, including defense manufacturing, telecommunications, energy production, artificial intelligence, and the automotive industry.

\56\ See 90 FR 48004 (October 3, 2025).

\57\ See letters of support from five semiconductor equipment manufacturing suppliers in the docket for this action.

Given the information provided by the petitioner on the need for more time to test, qualify, and validate substitutes, additional related information from five semiconductor manufacturing equipment suppliers, and comments on the proposed rule, the EPA agrees that a transition to available substitutes will be able to be made by January 1, 2030. The EPA also finds that semiconductor manufacturing equipment faced technically infeasible requirements to transition and that companies that run facilities with such equipment would have been forced to delay operations or invest in costly pre-commercial technologies. To the extent that productivity may have been impacted, the costs could have been significantly larger than the costs of refrigeration. The Agency concludes that the targeted relief provided for this equipment is appropriate given our change in understanding of the availability of substitutes and the overall economic costs and environmental impacts. The Agency describes and responds to comments in section IV.B of this preamble and the Response to Comments document in the docket.

The EPA is finalizing, as proposed, amendments to the limits for supermarket systems to establish a graduated schedule with an interim limit of 1,400 starting January 1, 2027, and 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032. The EPA is also finalizing a provision allowing for a 15 percent increase in cooling capacity of an existing supermarket system without triggering the requirements that apply to new installations. 1. Background

Supermarket systems, also known as multiplex or centralized systems, operate with racks of compressors installed in a machinery room where different compressors turn on to match the refrigeration load necessary to maintain temperatures in display cases in the sales area. Direct supermarket designs circulate refrigerant from the machinery room to the sales area, where it evaporates in display-case heat exchangers, and then returns in vapor phase to the suction headers of the compressor racks.\58\ Indirect supermarket designs include secondary loop systems and cascade refrigeration systems. Indirect systems use a chiller or other refrigeration system to cool a secondary fluid that is then circulated throughout the store to the cases. Compact chiller versions of an indirect system rely on a lineup of 10 to 20 units, each using small charge sizes. As the refrigeration load changes, so does the number of active chillers. Each compact chiller is an independent unit with its own refrigerant charge, reducing the potential volume of refrigerant that could be released from leaks or catastrophic failures. Despite the term “chiller” used in the description, these systems are considered supermarket systems for purposes of 40 CFR part 84, subpart B. Another type of supermarket design, often referred to as a distributed refrigeration system, uses an array of separate compressor racks located near the display cases rather than having a central compressor rack system. Each of these smaller racks handles a portion of the supermarket load,\59\ with 5 to 10 such systems in a store.\60\

\58\ Supermarket walk-in cold rooms are often integrated into the system and cooled similarly, but a dedicated condensing unit can be provided for a given storage room.

\59\ A supermarket may also use other types of refrigeration equipment covered by separate subsectors, including stand-alone units, remote condensing units, refrigerated beverage dispensers, and ice machines. Such equipment is not a part of the “supermarket system” subsector for purposes of 40 CFR part 84, subpart B merely as a result of being located in a supermarket.

\60\ See 88 FR 73157-58 (October 24, 2023).

Supermarket systems account for a significant amount of HFC demand. In particular, supermarket systems accounted for 24 percent of the demand for HFCs in the refrigeration and AC/HP sector in 2025.\61\ Supermarket systems' large charge sizes and higher leak rates than many other subsectors \62\ drive the demand for HFCs in these systems. Prior to 2010, this subsector used R-22, which is an ozone-depleting substance (ODS) that has been phased out, consistent with the requirements of title VI of the CAA and its implementing regulations. Since 2010, the majority of refrigeration systems in this subsector have used refrigerants such as R-404A, R-407A, and R-507A. More recently, supermarket systems have transitioned to substitutes such as HFC/hydrofluoroolefin (HFO) blends, like R-448A, R-449A, and R-513A, while a portion of the market has transitioned to CO2.

\61\ See EPA's Vintaging Model of ODS Substitutes Peer Review Factsheet, in the docket for this action.

\62\ See Annex 3.9 of the 2024 U.S. Inventory of GHG Emissions and Sinks, pg. 113, https://www.epa.gov/system/files/documents/2024-04/us-ghg-inventory-2024-annex-3-additional-source-or-sink-categories-part-a.pdf.

The 2023 Final Rule established restrictions on the installation of HFCs and HFC blends in new supermarket systems starting January 1, 2027. The limit finalized in the 2023 Final Rule was 150 for systems with refrigerant charge capacities greater than or equal to 200 pounds, and 300 for systems with refrigerant charge capacities less than

200 pounds or for the high temperature side of cascade systems irrespective of the total charge capacity. The EPA distinguished between larger and smaller supermarket systems by their refrigerant charge capacity based on a distinction between charge sizes in the safety standards.\63\

\63\ The same distinction exists for systems in industrial process refrigeration, cold storage warehouses, and retail food remote condensing units. Elsewhere this notice refers to these limits as “150 or 300, as applicable” with the meaning described here. See 87 FR 76775-76 (December 15, 2022).

The 2023 Final Rule would have required new retail food supermarket systems to be installed with refrigerants below a 150 or 300 limit, as applicable, including CO2, certain HFOs, or certain HFC/HFO blends.\64\ While some retailers had installed CO2 in new systems at the time, certain HFOs and HFC/HFO blends were still under development and had not yet been listed by the SNAP program as acceptable for use in new supermarket systems. While these additional options were listed by SNAP in June 2024,\65\ and in advance of the January 1, 2027, compliance date, the 2023 Final Rule would have largely required retailers to install either CO2 or newly listed alternatives.

\64\ See 88 FR 73158-59 (October 24, 2023).

\65\ See 89 FR 50410 (June 13, 2024).

Certain food retailers and a trade association representing the supermarket industry expressed concerns about the limited number and types of substitutes that the EPA determined in the 2023 Final Rule that would be available for use in supermarket systems by January 1, 2027. Specifically, they stated the rule restricts the food industry to a handful of substitute refrigerants, including CO2, ammonia,\66\ and those that are flammable,\67\ which they said are impractical, infeasible, or create safety concerns.\68\

\66\ The ASHRAE designation for ammonia is R-717.

\67\ ANSI/ASHRAE Standard 34-2024 Designation and Safety Classification of Refrigerants. This standard assigns a designation consisting of two to three alphanumeric characters (e.g., A2L or B1). The initial capital letter indicates the toxicity, and the numeral and trailing letter, if any, denotes flammability. The toxicity class is determined based on allowable exposure and is signified with a capital letter, where “A” denotes lower toxicity and “B” denotes refrigerants of higher toxicity. The standard also assigns refrigerants a flammability classification of 1, 2, 2L, or 3 based upon the results of standardized testing for flame propagation, heat of combustion, lower-flammability limit (LFL), and burning velocity. The flammability classification “1” is given to refrigerants that show no flame propagation. The flammability classification “2L” is given to refrigerants that have lower flammability. The flammability classification “2” is given to refrigerants that are flammable. The flammability classification “3” is given to refrigerants that have higher flammability.

\68\ See trade association's letter to the EPA, dated February 11, 2025, in the docket for this action.

In addition, they asserted that CO2 technologies are unreasonably costly, and that, in their current state, they expend a significant amount of energy to function at a cooling level comparable to commonly used HFCs, that such technologies are unreliable, that leaks are difficult to detect and repair, and that such leaks can be catastrophic to the system's performance.\69\ These food retailers shared that since water is used to cool CO2 in such systems, some states' water laws, like those in Nevada, would also be prohibitive to the effective use of CO2 systems.\70\ They also asserted that CO2 is not suitable for very large stores, such as those that are 50,000 square feet or larger. They also raised safety concerns about using ammonia, a regulated, toxic, and flammable substance, in some retail environments.\71\ These food retailers also said that refrigerants with flammability classifications, such as A2L and A3 refrigerants, may not be universally available due to delays in updates to local building codes and potential shortages in technicians trained to use them. Furthermore, these food retailers are concerned that future regulation of per- and polyfluoroalkyl substances (PFAS) could require retailers to change systems again from certain compliant fluorinated refrigerants to others.\72\ Based on these concerns, food retailers requested additional time to allow the technology and building codes to catch up. They requested the EPA move the compliance deadline for supermarket systems to the end of 2032 and suggested an interim limit of 1,400 starting January 1, 2027.\73\ In the proposal for this rulemaking, the EPA requested comments on various topics including on costs associated with transitioning to refrigerants in supermarkets systems below the compliance limit of 150 or 300, as applicable, as well as costs associated with meeting an interim compliance limit of 1,400.

\69\ Id.

\70\ See Memorandum--EPA Meetings Related to the Technology Transitions Reconsideration Notice of Proposed Rulemaking, April 18, 2025, in the docket for this action.

\71\ See trade association's letter to the EPA, dated February 11, 2025, in the docket for this action.

\72\ CO2, hydrocarbons, and ammonia are not fluorinated chemicals and are not PFAS. The EPA notes that the Federal Government has not adopted a specific definition of PFAS and has not included HFCs or HFOs in any PFAS-related restrictions.

\73\ See trade association's presentation dated April 18, 2025, in the docket for this action.

The EPA proposed an interim limit of 1,400 starting January 1, 2027, for new supermarket systems. Starting January 1, 2032, the EPA proposed the limit for supermarket systems to be 150 or 300, depending on the characteristics of the system, as described previously in this section.

A trade association representing the supermarket industry also requested clarifications and potential changes to the codified regulations at 40 CFR 84.54(e)(2) and (3) to ensure that certain routine store refreshes, remodels, or layout changes do not trigger the requirements for new systems.\74\ The 2023 Final Rule discussed two scenarios in which the EPA would consider modifications to an existing system to be equal to a new installation requiring the use of compliant refrigerants:

\74\ See email from trade association, dated April 24, 2025, in the docket for this action.

When an existing system's cooling capacity is increased as measured in British Thermal Units (BTU) per hour, and

When replacing 75 percent or more of evaporators (by number) and 100 percent of the compressor racks, condensers, and connected evaporator loads of an existing system.

The trade association stated that it is normal for stores to modestly expand the cooling capacity of existing systems when doing a remodel to accommodate additional products and layouts. They gave a specific example in which expanding a refrigerated case by 60 inches could increase the overall cooling capacity of the system, meaning it would be treated as a new system under the regulations at 40 CFR part 84 subpart B. The trade association requested that the EPA allow supermarkets to increase the cooling capacity measured in BTU per hour by up to 25 percent before the equipment is considered a new system. The EPA requested comments on whether to allow supermarket systems to expand cooling capacity by some amount without triggering the criteria for installation of a new system, and if so, what that increase could be (e.g., 25 percent).

The EPA requested comments on whether to allow supermarket systems to increase cooling capacity to a certain degree without triggering a new installation during routine store refreshes, remodels, or layout changes. The EPA did not propose a specific increase in cooling capacity that would be allowable without triggering a new installation of a supermarket system.

The EPA is finalizing, as proposed, amendments to the limits for supermarket systems to establish a graduated schedule with an interim limit of 1,400 starting January 1, 2027, and 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032. The EPA is also finalizing a provision allowing for a 15 percent increase in cooling capacity of an existing supermarket system without triggering the requirements that apply to new installations. a. Graduated Schedule

The EPA is finalizing a graduated schedule for the use of HFCs in new supermarket systems as proposed. Specifically, the EPA is relaxing the existing limit, on an interim basis, to 1,400 starting January 1, 2027, and a limit of 150 or 300 starting January 1, 2032. The limit of 150 is for supermarket systems with refrigerant charge capacities greater than or equal to 200 pounds, and 300 for supermarket systems with refrigerant charge capacities less than 200 pounds or for the high temperature side of cascade systems irrespective of the total charge capacity. The limits of 150 or 300, as described here, are the same limits as those promulgated with the 2023 Final Rule, just on an extended timeline. The EPA has reassessed the four factors under AIM Act subsection (i)(4) given the additional information received ahead of the October 2025 Proposal and during the comment period. The Agency understands the need for additional flexibility for supermarket systems in the near term, and acknowledges the complexity involved with designing and installing such systems and potential challenges with building code adoption, particularly at the local level. The interim limit provides additional flexibility to retailers installing new equipment in the near term. The EPA also notes that challenges in deploying such systems vary across certain geographical areas of the United States which can result in lagging adoption in certain areas. The targeted relief in this rule is appropriate given changes in our understanding of the availability of substitutes and the overall economic costs and environmental impacts. The Agency describes and responds to comments, including those related to building codes, energy efficiency, and more, in section IV.C of this preamble and the Response to Comments document in the docket.

The EPA also recognizes that some supermarkets already use refrigerants that would have complied with the 2023 Final Rule's limits. This final rule does not prevent manufacturers or installers from choosing to use refrigerants below the limits of 150 or 300 ahead of the new compliance requirements for new systems. The EPA anticipates the additional time for compliance will allow these systems to continue to be improved and have additional widespread availability across the country. Supermarket systems are not off-the-shelf systems and are configured with many different components to meet the specific needs of store in which it will be used. The graduated schedule considers this as some retailers may transition to these available substitutes sooner than January 1, 2032, while others may require additional flexibility. b. Expansion of Existing Supermarket Systems

In this final rule, the EPA is establishing that an increase in cooling capacity of a supermarket system measured in BTU per hour of up to 15 percent would not be considered a new installation. The EPA is aware that supermarkets often undergo routine store refreshes, remodels, or layout changes which may occur once or twice over the lifetime of the supermarket system to update the look of the retail floor or improve overall efficiency. The proposed rule discussed the EPA's intention, consistent with past practice from the phaseout of R- 22, where the Agency considered if there was sufficient cooling capacity within the system to support the expansion (e.g. new display cases), then the store is not changing the intended purpose of the system, and may use virgin R-22 after the modification/remodel. If the expansion includes an increase in cooling capacity, then the EPA presumes that the system's purpose is changing and a new system is being manufactured. In other words, changes that expanded cooling capacity for R-22 supermarket systems beyond the initial system designs were treated as new systems. In this rule the EPA is acknowledging that for the purposes of subsection (i) of the AIM Act, minor changes during store refreshes, remodels, or layout changes do not trigger treatment as a new system and has set an upper bound as discussed in section IV.C.2 of this preamble.

The EPA is finalizing amendments to the limits for retail food remote condensing units to establish an interim limit of 1,400 upon the effective date of this rule, and 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032. 1. Background

Remote condensing units are a type of retail food refrigeration equipment with refrigeration capacities typically ranging from 1 kW to 20 kW (0.3 to 5.7 refrigeration tons). They are composed of one (and sometimes two) compressor(s), one condenser, and one receiver assembled into a single unit, normally located external to the sales area. This equipment is connected to one or more nearby evaporator(s) used to cool food and beverages stored in display cases and/or walk-in storage rooms. A cascade system might be used, for example, to reach low temperatures in a long-term storage room. A supermarket often uses remote condensing units in food retail environments such as dairy and deli displays. Remote condensing units are also commonly installed in convenience stores and specialty shops, such as bakeries and butcher shops.\75\

\75\ See 88 FR 73157 (October 24, 2023).

The 2023 Final Rule established restrictions on the use of HFCs in new remote condensing unit systems installed starting January 1, 2026. The limit was 150 for systems with refrigerant charge capacities greater than or equal to 200 pounds, and 300 for systems with refrigerant charge capacities less than 200 pounds or for the high temperature side of cascade systems irrespective of the total charge capacity. The EPA distinguished between larger and smaller remote condensing units by their refrigerant charge capacity based on a distinction between charge sizes in the safety standards.\76\

\76\ See 87 FR 76775-76 (December 15, 2022).

The 2023 Final Rule would have required new retail food remote condensing unit systems to be installed with refrigerants below a 150 or 300 limit, as applicable, including CO2, certain HFOs, or certain HFC/HFO blends.\77\ In general, retail food remote condensing units have lower relative charge sizes compared to supermarket systems, often under 200 pounds, meaning they can generally use refrigerants complying with the 300 limit. While some retailers had installed CO2 in new systems at the time, other alternatives including certain HFOs and HFC/HFO blends were still under development and had not yet been listed by the SNAP program as acceptable for use in new remote

condensing units. While these additional options were listed by SNAP in June 2024,\78\ and in advance of the January 1, 2026, compliance date, the 2023 Final Rule would have largely made these relatively new HFC/ HFO blends as the primary options for new installations of remote condensing units.

\77\ See 88 FR 73157 (October 24, 2023).

\78\ See 89 FR 50410 (June 13, 2024).

Certain supermarket retailers and a trade association expressed concerns about the limited number and types of substitutes that the EPA determined in the 2023 Final Rule would be available for use in remote condensing units by January 1, 2026. Specifically, they stated that the rule restricts the food industry to a handful of substitute refrigerants, including CO2, ammonia, and those that are flammable,\79\ which they stated are either impractical, infeasible, or create safety concerns.\80\

\79\ ANSI/ASHRAE Standard 34-2024 Designation and Safety Classification of Refrigerants.

\80\ See trade association's letter to the EPA, dated February 11, 2025, in the docket for this action.

In addition they asserted that CO2 technologies are costly, and that, in their current state, they expend a significant amount of energy to function at a cooling level comparable to commonly used HFCs, that such technologies are unreliable, that leaks are difficult to detect and repair, and that such leaks can be catastrophic to the system's performance.\81\ These food retailers also said that refrigerants with flammability characteristics, such as A2L and A3 refrigerants, may not be universally available due to delays in updates to local building codes and potential shortages in technicians trained to use them. Furthermore, these food retailers are concerned that future regulation of PFAS could require retailers to change systems again from certain compliant fluorinated refrigerants to others.\82\ Based on these concerns, food retailers requested additional time to allow the technology and building codes to catch up. They requested that the EPA move the compliance deadline for retail food remote condensing units to the end of 2032 with an interim limit of 1,400 starting January 1, 2026.\83\

\81\ Id.

\82\ CO2, hydrocarbons, and ammonia are not considered PFAS. The EPA notes that the Federal Government has not adopted a specific definition of PFAS and has not included HFCs or HFOs in any PFAS-related restrictions.

\83\ See trade association's presentation dated April 18, 2025, in the docket for this action.

The EPA considered concerns from stakeholders in the retail food industry to allow additional flexibility in refrigerant choice for retail food remote condensing units, understanding there may be challenges such as building codes to adopting newer technologies. Thus, the EPA proposed a graduated schedule with an interim limit of 1,400 starting January 1, 2026, for new retail food remote condensing units to allow additional flexibility for a limited period of time. Such additional flexibility allows for the use of nonflammable options such as R-448A and R-449A. As previously described, the EPA also proposed limits of 150 or 300, depending on the characteristics of the system, starting January 1, 2032, given that the Agency anticipated that the period of the interim limit would be a sufficient amount of time for implementation challenges to resolve. 2. Final Rule

The EPA is finalizing the graduated schedule for the use of HFCs in new retail food remote condensing units similar to what was proposed. Specifically, the EPA is relaxing the existing limit, on an interim basis, to 1,400 upon the effective date of this rule, and limits of 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032. For remote condensing units with a charge size of 200 pounds or more, excluding the high temperature side of a cascade system, the limit is 150. For remote condensing unit systems with a charge size less than 200 pounds or remote condensing unit systems on the high temperature side of a cascade system, the limit is 300. The limits of 150 or 300, as described here, are the same limits as those promulgated with the 2023 Final Rule, just on an extended timeline. The EPA has reassessed the factors under AIM Act subsection (i)(4) given the additional information received ahead of the October 2025 Proposal and during the comment period. The Agency concludes that the targeted relief in this rule is appropriate given changes in our understanding of the availability of substitutes, particularly with regard to building codes and safety, and the overall economic costs. Similar to supermarket systems, the interim limit temporarily allows for the use of a set of certain refrigerants and reduces the burden on remote condensing unit systems as they transition to new substitutes. The EPA also recognizes that many remote condensing units are already using refrigerants that would have complied with the 2023 Final Rule's limits. This rule does not prevent anyone from choosing to use refrigerants below the limits of 150 or 300 ahead of the new compliance requirements for new systems. The Agency describes and responds to comments in section IV.D of this preamble and the Response to Comments document in the docket.

The EPA is finalizing amendments to the limits for cold storage warehouses to establish a graduated schedule with an interim limit of 700 upon the effective date of this rule, and 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032. 1. Background

Cold storage warehouses are refrigerated facilities used for the storage of temperature-controlled substances. Refrigeration systems within cold storage warehouses can be divided into two categories: packaged systems and central plant systems. Central plants are custom- built refrigeration systems that are typically used in large, refrigerated warehouses with cooling capacities that range from 20 to 5,000 kW. Central plant systems deliver cool air to the refrigerated space through evaporators, which are typically suspended from the ceiling in the refrigerated space. The evaporators are connected through a piping network to multiple compressors located in a central machine room, and a condenser, which is typically mounted outside near the compressors. Central plant systems may have a direct or indirect (secondary loop) design. Direct systems circulate a primary refrigerant throughout the refrigerated space. In an indirect system, a primary refrigerant cools a secondary refrigerant in the machine room, and the secondary refrigerant is then circulated throughout the refrigerated space.\84\

\84\ See 88 FR 73162 (October 24, 2023).

The 2023 Final Rule established restrictions on the use of HFCs in new cold storage warehouses installed starting January 1, 2026. The limit is 150 for systems with refrigerant charge capacities greater than or equal to 200 pounds, and 300 for systems with refrigerant charge capacities less than 200 pounds or for the high temperature side of cascade systems irrespective of the total charge capacity.

The 2023 Final Rule would have required new cold storage warehouses to be installed with refrigerants below a 150 or 300 limit, as applicable, including ammonia, CO2, certain HFOs, or certain HFC/HFO blends.\85\ While most cold storage warehouses had used ammonia at the time, substitutes with lower toxicity and lower flammability were still under development and had

not yet been listed by the SNAP program as acceptable for use in new cold storage warehouses. While additional options were listed by SNAP in June 2024,\86\ in advance of the January 1, 2026, compliance date, the 2023 Final Rule would have largely made these newer refrigerant blends, ammonia, or CO2 the only options for new installations of cold storage warehouses.

\85\ See 88 FR 73157 (October 24, 2023).

\86\ See 89 FR 50410 (June 13, 2024).

A new trade association submitted a request to the EPA on March 6, 2025, to adjust the limits for cold storage warehouses from 150 or 300, as applicable, to 700. The trade association highlighted that ammonia, a higher toxicity and flammable refrigerant, can present potential safety concerns particularly when cold storage warehouses are not located in isolated, unpopulated areas. The trade association cited a number of recent examples of fatalities, injuries, and facility evacuations related to the use of ammonia as a refrigerant in cold storage warehouses in the United States.

The trade association's request was to adjust the limit for cold storage to allow for the use of additional refrigerants, and in particular, R-513A. The trade association identified R-513A as a refrigerant in this subsector that met their safety, commercial availability, energy efficiency, and usability requirements. The trade association indicated that the substitutes identified by the EPA in the 2023 Final Rule would not necessarily be available in every situation due to flammability or toxicity concerns, commercial availability, decreased energy efficiency, not being mechanically practical due to excessive displacement, building codes not being updated, and/or economic costs.\87\

\87\ See request from trade association, dated March 6, 2025, in the docket for this action.

The EPA also received information from another trade association representing cold storage warehouses on June 9, 2025, in response to the March 6, 2025, request, concerning a 2023 survey from the Global Cold Chain Alliance (GCCA).\88\ That survey showed that over 90 percent of cold storage warehouse refrigeration systems in the United States used either ammonia or CO2.

\88\ See letter from trade association, dated June 9, 2025, in the docket for this action.

The EPA proposed an interim limit of 700 starting January 1, 2026, for new cold storage warehouses. Starting January 1, 2032, the EPA proposed limits of 150 or 300, depending on the characteristics of the system, as described previously. To balance near-term safety, feasibility, and substitute availability, the EPA proposed an interim limit of 700 for new cold storage warehouses to allow the use of nonflammable, lower toxicity options such as R-513A, where ammonia or alternatives with flammability designations are impractical due to documented safety incidents, building code constraints, mechanical and efficiency considerations, and/or supply-chain limitations. Beginning January 1, 2032, the EPA proposed to lower the limit to 150 or 300, as applicable in anticipation that building codes will be updated, technologies will mature, and market availability of substitutes will expand. 2. Final Rule

The EPA is finalizing the graduated schedule for the use of HFCs in new cold storage warehouses similar to what was proposed. Specifically, the EPA is amending the existing limit, on an interim basis, to 700, upon the effective date of this rule, and limits of 150 or 300, depending on charge size or whether it is part of the high temperature side of a cascade system, starting January 1, 2032. For cold storage warehouse systems with a charge size of 200 pounds or more, excluding the high temperature side of a cascade system, the limit is 150. For cold storage warehouse systems with a charge size less than 200 pounds, or for the high temperature side of a cascade system, the limit is 300. The limits of 150 or 300, as described here, are the same limits as those promulgated with the 2023 Final Rule, just on an extended timeline. The EPA has reassessed the factors under AIM Act subsection (i)(4) given the additional information received ahead of the October 2025 Proposal and during the comment period. The Agency concludes that the targeted relief in this rule is appropriate given changes in our understanding of the availability of substitutes, and in particular a need for additional non-flammable, lower toxicity alternatives in the near term. The interim limit temporarily allows for the use of a set of certain refrigerants and reduces the burden on cold storage warehouse systems as they transition to new substitutes. The EPA also recognizes that most cold storage warehouses are already using refrigerants that would have complied with the 2023 Final Rule's limits, including ammonia and CO2. This rule does not prevent anyone from choosing to use refrigerants below the limits of 150 or 300 ahead of the new compliance requirements for new systems.

While entities in many areas of the United States can and do use substitute refrigerants in this subsector, the EPA acknowledged in the proposal that factors such as the use of ammonia in a system containing thousands of pounds of refrigerant charge could pose a safety risk in densely populated areas if a leak were to occur, or if such a system were to be handled improperly and could hinder compliance on a nationwide scale, including in densely populated areas. The Agency describes and responds to comments in section IV.E of this preamble and the Response to Comments document in the docket.

The EPA did not propose and is not finalizing changes to the treatment of new condensing units used as replacements in the residential and light commercial AC/HP subsector. 1. Background

The residential and light commercial AC/HP subsector includes many types of equipment, from self-contained products such as packaged terminal air conditioners and window AC units to unitary split systems such as ducted and non-ducted mini-splits, multi-splits, and ducted air conditioners and heat pumps. This section pertains only to the treatment of condensing units used in split AC/HP systems, including mini-splits and multi-splits, that are field assembled and charged. These systems consist of an outdoor unit with a condenser and a compressor, refrigerant lines, and an indoor unit with an evaporator. The evaporator and air handler may, or may not, be connected to ducts to carry conditioned air throughout a building.

The unit in which the condenser and compressor are packaged together is called a “condensing unit.” The condensing unit discharges heat and is typically located outside. ASHRAE defines a condensing unit as a “machine designed to condense refrigerant vapor to a liquid by compressing the vapor in a positive displacement compressor and rejecting heat to a cooling medium. A condensing unit usually consists of one or more positive displacement compressors and motors, condensing coils, liquid receivers, and other devices mounted on a common base.” \89\

\89\ See ASHRAE Terminology in the docket for this action, and at https://terminology.ashrae.org.

In proposing the 2023 Final Rule (hereinafter “Proposed 2023 Rule”) the EPA proposed that restrictions would apply to “products,” which would have

included condensing units.\90\ Specifically, the proposal stated, “effective January 1, 2025, no person may manufacture or import any product . . . as listed in Sec. 84.56(a)” (emphasis added).\91\ Likewise, “effective January 1, 2026, no person may sell or distribute, offer to sell or distribute, make available to sell or distribute, purchase or receive, attempt to purchase or receive, or export any product . . . as listed in Sec. 84.56(a)” (emphasis added). The proposed definition of “product” in 40 CFR 84.56(a) would have contained a non-exhaustive list that included “equipment, appliances, components, [and] subcomponents.” A condensing unit is a component of the larger unitary split AC/HP system and therefore, under the proposed rule, would have been subject to restrictions. Under that proposal, the condenser and compressor housed within a condensing unit would have been considered either components or subcomponents and would have been subject to restrictions.

\90\ See 87 FR 76738 (December 15, 2022).

\91\ 40 CFR 84.56(a)(24) lists “Residential and light commercial air-conditioning and heat pump systems, when using or intended to use a regulated substance or a blend containing a regulated substance with a global warming potential of 700 or greater, except for variable refrigerant flow air-conditioning systems.” The Proposed 2023 Rule did not distinguish between “products” and “systems” like the 2023 Final Rule.

The EPA received many comments on the Proposed 2023 Rule expressing concern about the impact of restricting components and subcomponents using legacy refrigerants. The comments were almost universally opposed, with the specific concerns varying on the type of restriction placed on the component, including: manufacture and import; sale and distribution; and the purchase and use to maintain existing equipment. Most comments were made in the context of refrigeration systems, such as supermarket systems, which contain numerous components, including multiple compressors on a rack, that are commonly replaced to keep the expensive and complex systems operational. One comment made in the context of AC systems expressed concern about the ability to honor warranties for existing systems without replacement components. Based on the concern expressed by commenters, the Agency removed components and subcomponents from the final definition of “product.” Instead, the final rule classified condensing units as one of five “specified components” at 40 CFR 84.52 to make clear that they were not subject to the restrictions on manufacture, import, sale, distribution, or export and thus allow for the continued servicing and maintenance of existing equipment. The EPA prohibited specified components using legacy refrigerant to be installed as new systems after the applicable installation compliance date.

After finalization of the 2023 Final Rule, the EPA received two administrative petitions, one from a chemical manufacturer and the other from a group of trade associations, requesting that the Agency reconsider that final rule as it applies to the residential and light commercial AC/HP subsector. The two administrative petitions requested reconsideration of separate provisions of the regulations as means to achieve a similar outcome, that is, reconsideration of the treatment of condensing units used as replacements in existing systems.

The administrative petition from the chemical manufacturer requested that the EPA remove provisions that allow the continued use of specified components that use regulated substances above the 700 limit in the residential and light commercial AC/HP subsector. The petitioner stated that the EPA did not propose a definition of “specified component,” nor did it propose to exempt specified components from the HFC use prohibitions. The petitioner noted that the EPA proposed the opposite by including components and subcomponents in the list of products subject to the proposed restrictions. The petitioner stated that the final rule allows for unlimited replacement of condensers, evaporators, and compressors in this subsector, thereby extending the life of existing systems beyond their designed lifetimes without taking comment on the impacts of such extended use. In meetings with the EPA regarding the petition, the petitioner clarified that its concern was limited to the replacement of condensing units used in split AC systems in the residential and light commercial AC/HP subsector, not the other four specified components, nor condensing units used in refrigeration subsectors.\92\

\92\ See Memorandum--EPA Meetings Related to the Technology Transitions Reconsideration Notice of Proposed Rulemaking in the docket for this action.

The administrative petition from the group of trade associations requested that the EPA make a determination that replacing certain condensing units in the residential and light commercial AC/HP subsector would be considered the installation of a new system under 40 CFR 84.54(e). The administrative petition is limited to condensing units in this subsector that are designed for use with a single condenser and a single evaporator. The administrative petition requested that the EPA not restrict condensing units used in variable refrigerant flow (VRF) systems,\93\ multi-split systems, and commercial AC systems with more than one condenser and/or more than one evaporator. After submitting their initial administrative petition, the group of trade associations submitted a letter to the EPA containing supplemental information that limited their request to condensing units with a capacity less than 65,000 BTUs.\94\

\93\ See 88 FR 73178 for a description of VRF systems.

\94\ See supplemental letter from trade associations, dated April 30, 2024, in the docket for this action.

In the proposal for this rule and in response to stakeholder administrative petitions, the EPA proposed to retain the requirements established by the 2023 Final Rule regarding the treatment of condensing units used in the residential and light commercial AC/HP subsector. The proposal provided an opportunity for the public to comment on the treatment of condensing units in this subsector and in doing so, the EPA noted it was addressing one petitioner's concerns about their inability to comment on changes made between proposal and finalization of the 2023 Final Rule regarding the treatment of components. 2. Final Rule

In this final rule, the EPA is not making any changes to the treatment of new condensing units in the residential and light commercial AC/HP subsector. This includes no change to the definitions at 40 CFR 84.52, the installation restriction at 40 CFR 84.54(c)(1), the list of actions that the EPA considers an installation of a new system at 40 CFR 84.54(e), the exemption for components at 40 CFR 84.56(b), or the labeling, reporting, and recordkeeping requirements applicable to specified components. Allowing a continued market (i.e., manufacture, import, export, sale, or distribution) for specified components enables end-users to maintain their existing systems, even if those systems use legacy HFC refrigerants. By making no changes to the current regulations, a homeowner can choose to replace their failed condensing unit rather than purchase a whole new system. The EPA's decision to not change the treatment of condensing units aligns with subsection (i)(7)(B) of the AIM Act and consistent with the Agency's historical practice of allowing repair of legacy equipment throughout its useful life. This final decision is also consistent with the

Presidential Memorandum titled Delivering Emergency Price Relief for American Families and Defeating the Cost-of-Living Crisis, which directs “the heads of all executive departments and agencies to deliver emergency price relief, consistent with applicable law, to the American people and increase the prosperity of the American worker,” including by “pursuing appropriate actions to . . . eliminate counterproductive requirements that raise the costs of home appliance[.]” If restrictions were to be placed on replacing the condensing unit, the owner's only recourse would be to replace the entire system. Installing a new system is more costly than replacing just the condensing unit, particularly if the system is relatively new, and in some instances, warranties or insurance will only cover the replacement of like equipment. The Agency describes and responds to comments in section IV.F of this preamble and the Response to Comments document in the docket.

The EPA is finalizing provisions related to certain laboratory equipment within the industrial process refrigeration subsector. This final rule extends the compliance date for refrigerated centrifuges and laboratory shakers to January 1, 2028. 1. Background a. Refrigerated Centrifuges

A refrigerated centrifuge is a laboratory device that spins samples at a high speed while keeping them at a low, controlled temperature. Refrigerated centrifuges are a niche subset of equipment used in laboratories and have narrow technical requirements which limit the refrigerants that can be used. The EPA understands that refrigerated centrifuges are critical for blood processing and other essential pharmaceutical and medical industries.

The 2023 Final Rule included refrigerated laboratory equipment within the IPR subsector.\95\ Specifically, the 2023 Final Rule stated that refrigerated laboratory equipment covered by either the 2nd edition of the UL 61010-2-011 standard or the 2nd edition of the UL 60335-2-89 standard are subject to the restrictions in the rule.\96\ The restrictions on the use of HFCs and HFC blends in new IPR equipment vary based on the lowest temperature at which the equipment is designed to operate, charge size, and the configuration of the equipment. IPR equipment with refrigerants entering the evaporator at temperatures between -50 [deg]C and -30 [deg]C have a compliance date of January 1, 2028, while IPR equipment with refrigerants entering the evaporator at temperatures at or above -30 [deg]C have a compliance date of January 1, 2026. These restrictions are codified at 40 CFR 84.54(a)(12) and 84.54(c)(10).

\95\ The EPA is not aware of IPR centrifuge configurations used for laboratory applications that would be covered by the IPR chiller subsector as opposed to the IPR subsector at 40 CFR 84.54(a)(10), (c)(5), or (c)(6).

\96\ See p. 209 of the Response to Comments document for the 2023 Final Rule.

The 2023 Final Rule excluded centrifuges with charge sizes above the threshold consistent with UL 61010-2-011. The EPA recognized that refrigerated centrifuges that contain less than 150 g of flammable refrigerant charge (or 370 g of nonflammable refrigerant charge) can meet the UL standards using refrigerants below the limits for IPR and are subject to the HFC use restriction. Conversely, the EPA recognized that refrigerated centrifuges that require more refrigeration capacity than can be achieved using refrigerants that meet the HFC use restrictions while meeting the charge size limits in UL 61010-2-011 are not restricted. This is because the refrigerants that meet the IPR restrictions are either flammable, have a higher toxicity, or have higher pressure than other available refrigerants, and as such, either require an upper limit on charge size to meet the UL standard's safety requirements or are outside the current scope of the UL standard altogether.

After issuance of the 2023 Final Rule, a manufacturer contacted the EPA concerning refrigerated centrifugal equipment that follows UL 61010-2-011 or UL 61010-2-020. The manufacturer stated that refrigerated centrifuges need to be tested to American National Standards Institute (ANSI)/UL standards 61010-2-011 or 61010-2-020 before mass production. The manufacturer described how UL 61010-2-020 requires a particular test for refrigerated centrifuges called the Maximum Credible Accident (MCA) test which assesses the safety of centrifugal equipment in a worst-case mechanical failure. The test simulates an accident scenario where the rotor assembly, a high-speed spinning part of the centrifuge, experiences catastrophic failure or becomes detached during rotation. This test ensures that the design and structure of the equipment are robust enough to contain debris and prevent personnel from hazardous exposure in such an event. The manufacturer explained that the MCA test itself is currently not designed in a manner that allows for testing of flammable or high- pressure refrigerants.

The EPA understands that this update to the UL safety testing procedure impacts all centrifuge manufacturers. The manufacturer noted that the MCA test was expected to be updated in 2025, before the January 1, 2026, compliance date, but that additional time would be needed for manufacturers to redesign, test, and certify centrifuges to the revised standards. The manufacturer later stated in a meeting that they anticipate that standards and equipment will be updated by January 1, 2028.\97\ The EPA understands that as of February 2026, the updates to UL 61010-2-020 have not yet been finalized to accommodate testing refrigerated centrifuges with the MCA test using flammable and high- pressure refrigerants. While the EPA does not know when the updates will be completed, we have no information to suggest it will not be completed by January 1, 2028.

\97\ See Memorandum--EPA Meetings Related to the Technology Transitions Reconsideration Notice of Proposed Rulemaking in the docket for this action.

The EPA proposed and is now finalizing an extension of the compliance date for refrigerated laboratory centrifuges within the IPR subsector from January 1, 2026, to January 1, 2028. This extension allows additional time for the industry standard setting process to finalize updated test procedures specific to refrigerated centrifuges so that new refrigerants can be safely deployed for use in this niche application. b. Refrigerated Laboratory Shakers

Laboratory shakers are specialized pieces of equipment used in scientific and medical laboratories to continuously agitate liquid biological samples at controlled temperatures. These devices are designed for applications that require temperature-sensitive conditions, such as growing microbial cell cultures or eukaryotic tissue cultures. The temperature range can span in some applications from around 4 [deg]C to 80 [deg]C.

The 2023 Final Rule indicated that refrigerated laboratory equipment that use an HFC or blend containing HFC(s) are regulated within the IPR subsector.\98\ Refrigerated laboratory shakers are covered by the UL 60335-2-89 standard

and are regulated as a part of this subsector.

\98\ The EPA is not aware of IPR shaker configurations used for laboratory applications that would be covered by the IPR chiller subsector as opposed to the IPR subsector at 40 CFR 84.54(a)(10), (c)(5), or (c)(6).

Under the regulations at 40 CFR 84.54, IPR equipment with refrigerants entering the evaporator at temperatures at or above -30 [deg]C have a compliance date of January 1, 2026. After issuance of the 2023 Technology Transition Rule, a manufacturer contacted the EPA regarding refrigerated laboratory shaker equipment. The manufacturer stated that there are currently limited alternatives for small, compact IPR systems, such as laboratory shakers.\99\ The manufacturer noted that while there are some non-HFC alternatives currently on the market in some laboratory equipment applications, such as R-290 \100\ and R- 1234yf, these alternatives pose safety, efficiency, and cooling capacity challenges in compact lab environments and in certain laboratory applications. For example, flammability is a particular concern from both a regulatory and safety perspective, as laboratories often have open flames, solvents, or other electronics present that could trigger an ignition.

\99\ See materials from manufacturer at EPA-HQ-OAR-0005-0007.

\100\ Commonly known as propane.

Since laboratory shakers are used in various cell culture applications, the manufacturer also described how a wide temperature operation range and precise temperature control are crucial to ensure optimal cell growth conditions and experimental accuracy. A temperature operation range that extends as low as 4 [deg]C and up to 80 [deg]C allows for a range of biological laboratory research applications. The manufacturer indicated that currently R-134a is the only refrigerant used that can achieve such a wide temperature range. Not all shakers have this wide temperature range, and in particular, some do not extend as high as 80 [deg]C. Shakers that use R-600a \101\ or a Peltier cooling method \102\ can operate at temperatures as high as 60 [deg]C. This limits the capability of such shakers from operating at temperatures above 60 [deg]C, in which certain niche research processes are conducted.

\101\ Commonly known as isobutane.

\102\ Peltier cooling uses a thermoelectric effect for cooling. It does not contain refrigerant.

While a range of options are used to control temperature in laboratory shakers, including compliant refrigerants that can meet the requirements in some refrigerated laboratory shaker applications, there remain some use cases in which compliant refrigerants are unable to meet the requirements. The manufacturer noted that temperature accuracy to within 0.1 [deg]C is required to maintain the integrity of the cell cultures and reliability of results in certain research applications.\103\ The manufacturer shared information that illustrated how not all shakers have this precise temperature control capability. Some laboratory shakers can provide an accuracy within 0.3 [deg]C, and some of those are already using compliant refrigerants, including R- 600a.

\103\ See materials from manufacturer at EPA-HQ-OAR-0005-0007.

The manufacturer noted that one feasible alternative that could achieve desired temperature specifications is CO2, but that current IPR systems for this refrigerant are primarily designed for large-scale industrial refrigeration systems and that there are limited solutions for small-scale laboratory equipment. Systems are currently in development but are not expected to be available until mid-2027 at the earliest.\104\

\104\ See materials from manufacturer at EPA-HQ-OAR-0005-0007.

The EPA proposed and is now finalizing an extension of the compliance date for refrigerated laboratory shakers within the IPR sector from January 1, 2026, to January 1, 2028. This extension is to allow additional time for the safe deployment of new refrigerants and not-in-kind substitutes (e.g., Peltier cooling) for use in this niche refrigerated laboratory application. 2. Final Rule

The EPA is extending the compliance date to January 1, 2028, for refrigerated laboratory centrifuges and refrigerated laboratory shakers within the IPR subsector. This extension does not apply to other types of equipment in the IPR subsector or to refrigerated laboratory equipment not discussed in this action. After reviewing public comments received during the comment period, the EPA is finalizing this extension as proposed. a. Refrigerated Centrifuges

Comments received on the October 2025 Proposal reiterated information received from requests to reconsider the compliance deadline for refrigerated laboratory centrifuges finalized in the 2023 Final Rule. This extension allows additional time for the industry standard setting process to finalize updated test procedures specific to refrigerated centrifuges so that new refrigerants can be safely deployed for use in this niche application. The EPA did not receive adverse comments opposing the proposal.

The EPA has reassessed the four factors under AIM Act subsection (i)(4) given the additional information received ahead of the October 2025 Proposal and during the comment period. Based on comments and the information provided by manufacturers, the Agency agrees that the MCA test required in UL 61010-2-020 cannot be performed until modifications are made to accommodate the safety risks associated with fire hazards, ballistic threats, or toxicity hazards and understands that the standards and equipment updates are expected to be completed by January 1, 2028. Therefore, the EPA concludes that the targeted relief in this rule is appropriate given changes in our understanding of the availability of substitutes and is extending the compliance date to January 1, 2028, for refrigerated centrifuges within the IPR subsector. The Agency describes and responds to comments in section IV.G of this preamble and the Response to Comments document in the docket. b. Refrigerated Laboratory Shakers

Comments received on the October 2025 Proposal reiterated information received from requests to reconsider the compliance deadline for refrigerated laboratory shakers finalized in the 2023 Final Rule. This extension is to allow additional time for the safe deployment of new refrigerants and not-in-kind substitutes (e.g., Peltier cooling) for use in this niche refrigerated laboratory application. The EPA did not receive adverse comments opposing the proposal.

The EPA has reassessed the factors under AIM Act subsection (i)(4) given the additional information received ahead of the October 2025 Proposal and during the comment period. Based on comments and the information provided by manufacturers, the Agency acknowledges that several refrigerants are currently being used in refrigerated laboratory shakers but that they do not all have the same temperature operation range or control capacity. The Agency is also aware that CO2 is being developed for use in laboratory shakers to have the necessary specifications that can meet manufacturers and researchers' requirements in time before 2028. As such, the EPA concludes that the targeted relief in this rule is appropriate given changes in our understanding of the availability of substitutes and is extending the compliance date from January 1, 2026, to January 1, 2028, for all refrigerated laboratory shakers, to provide additional time for compliant refrigerant options to be developed for refrigerated laboratory shaker uses. The

Agency describes and responds to comments in section IV.G of this preamble and the Response to Comments document in the docket.

The EPA is finalizing, as proposed, the removal of the deadline for installing residential and light commercial AC/HP systems when using equipment that was domestically manufactured or imported into the United States before January 1, 2025. 1. Background

The 2023 Final Rule restricted installation of new residential and light commercial AC/HP systems using refrigerants above a limit of 700 beginning January 1, 2025. Systems in this subsector include unitary split systems such as ducted and non-ducted mini-splits, multi-splits, and ducted air conditioners and heat pumps.

After that rule was finalized, the EPA received information including data concerning how the January 1, 2025, installation date restriction would result in substantial stranded inventory for residential new construction, including both single-family and multi- family dwellings, where builders order heating and cooling equipment well in advance of knowing the exact date of installation. The EPA published an IFR on December 26, 2023, to address the unique circumstances of this subsector to prevent equipment from being stranded.\105\ That rule extended the installation compliance date for such systems by one year, to January 1, 2026, so long as the equipment was manufactured in the United States or imported into the United States before January 1, 2025. Since publication of the IFR, other entities requested additional time beyond January 1, 2026, to install residential and light commercial AC/HP systems.\106\ These requesters shared that additional time is needed because of construction delays particularly for certain large construction projects (e.g., for multifamily housing) that have long timelines.\107\ Without further extension of the installation compliance date, they noted that there could still be stranded inventory of equipment domestically manufactured or imported before 2025.

\105\ See 88 FR 88825 (December. 26, 2023).

\106\ See comment on the IFR (88 FR 88825 (December. 26, 2023)) from the National Multifamily Housing Council and National Apartment Association, as well as a list of stakeholders who submitted relevant questions and comments to the EPA, both at EPA-HQ-OAR-0005- 0007.

\107\ See comment on the IFR (88 FR 88825 (December. 26, 2023)) from the National Multifamily Housing Council and National Apartment Association at EPA-HQ-OAR-0005-0007.

In addition, at the time of the 2023 Final Rule, the EPA understood that substitutes, including R-454B and R-32, were being developed and deployed. The rate of new installations that used these substitutes has increased significantly, in particular in 2025.\108\ This left larger inventories than expected of equipment using refrigerants above the 700 limit at risk of being stranded.

\108\ See HARDI press release, “A2L Equipment Reaches 90% of Market Share as Cooling Season Ends,” November 19, 2025, in the docket for this action.

Further, the EPA observed that the transition to equipment in the residential and light commercial AC/HP subsector using compliant refrigerants, including R-454B, saw unexpected supply issues during deployment.\109\ While there was a sufficient supply of R-454B, there were challenges supplying the refrigerant in service cylinders to contractors and technicians, resulting in R-454B scarcity in some regions. In particular, some contractors and technicians had difficulties securing R-454B refrigerant in the field to charge these units during installation.

\109\ See Memorandum--Overview of R-454B Refrigerant Shortage and Current Status, in the docket for this action.

The EPA proposed to remove the installation compliance date for the residential and light commercial AC/HP subsector if the components were manufactured domestically or imported into the United States before January 1, 2025, to avoid stranded inventory. The EPA also considered extending the installation compliance date to January 1, 2027, as an alternative means by which to also avoid stranding inventory. 2. Final Rule

The EPA is finalizing, as proposed, the removal of the deadline for installing residential and light commercial AC/HP systems that use specified components that were domestically manufactured or imported into the United States before January 1, 2025.

The EPA has reassessed the factors under AIM Act subsection (i)(4) given the additional information received ahead of the October 2025 Proposal and during the comment period. The EPA proposed and is now finalizing this provision to provide additional options to support consumers given the specific circumstances discussed in this section and in section IV.H of this preamble concerning the introduction of R- 454B equipment ahead of 2026 and the resulting supply chain issues observed in 2025. Removing the installation compliance date allows for the installation of the remaining inventory of R-410A equipment that had been manufactured in the United States or imported into the United States before January 1, 2025, for use in this subsector, which could be a lower cost option for consumers. The EPA does not expect there to be discernible impacts from those already modeled in the analysis for the 2023 Final Rule, since the total number of systems available for installation using legacy refrigerants would match what the Agency modeled for that rule. The EPA concludes that the targeted relief in this rule is appropriate given changes in our understanding of the supply chain issues that resulted in more limited availability of substitutes than was anticipated and overall economic costs. The Agency describes and responds to comments in section IV.H of this preamble and the Response to Comments document in the docket.

The EPA is making this final rule effective 60 days after publication in the Federal Register, as proposed.

Subsection (i)(6) of the AIM Act states that “no rule under this subsection may take effect before the date that is 1 year after the date on which the Administrator promulgates the applicable rule under this subsection.” \110\ The best reading of this statutory text is that the one-year clock begins upon promulgation of the “applicable rule” that established the restrictions at issue--here, the 2023 Final Rule, which invoked the EPA's discretionary authority under subsection (i) for the first time to establish the restrictions at issue in this reconsideration action. In other words, the one-year effective date delay requirement does not apply to subsequent rules that are unambiguously less stringent than the existing restrictions, including the relaxation or removal of existing restrictions.

\110\ See 42 U.S.C. 7675(i)(6).

The 2023 Final Rule described the EPA's interpretation of subsection (i)(6) of the AIM Act as applying to the

establishment of restrictions on the use of HFCs under subsection (i)(1) of the AIM Act. Based on that interpretation, the Agency established compliance dates for the restrictions on the domestic manufacture and import of products and installation of systems that were at least one year from the date of promulgation. At the same time, we did not delay compliance or effective dates for provisions pertaining to program administration and petitions processing and elected to make those provisions effective 60 days after publication in the Federal Register.\111\ Thus, in the 2023 Final Rule, the Agency recognized that subsection (i)(6) does not require a one year delayed effective date for all regulatory actions under subsection (i).

\111\ See 88 FR 73104 (October 24, 2023).

This interpretation flows from the statutory text of subsection (i)(6): “No rule under this subsection may take effect before the date that is 1 year after the date on which the Administrator promulgates the applicable rule under this subsection.” \112\ Congress's inclusion of the word “applicable” makes it clear that the “rule under this subsection” referred to at the beginning of the sentence may be different in at least some cases than the “applicable rule under this subsection” referenced at the end. The canon against surplusage argues that every word and phrase in a statute should be assumed to have an effect. If this section was drafted with the intent that the two rules referenced are always one and the same--i.e., that the effective date requirement applies to any rule--the word “applicable” could be simply struck from the text and the meaning would remain the same: “No rule under this subsection may take effect before the date that is 1 year after the date on which the Administrator promulgates the [ ] rule under this subsection.”

\112\ See 42 U.S.C. 7675(i)(6).

Assuming that the word “applicable” means something, the best interpretation of the statutory text in this provision is that the “applicable” rule is a rule that creates new restrictions for a particular sector or subsector, which is when a one-year delay accomplishes Congress's objectives. Providing a full year delay between promulgation and application of a compliance deadline is important when a new sector or subsector is being regulated, as with the 2023 Final Rule, to provide regulated parties sufficient notice to plan for and adjust to new restrictions. However, when the EPA is revising an existing restriction by, for example, providing additional time for compliance or changing a temperature threshold to make the previously existing restriction less stringent, the need for adequate notice to parties subject to the restriction is less compelling. In that case, the “applicable rule” is the rule that created the original restrictions, not a subsequent rule making the restrictions less stringent. That interpretation is consistent with the purpose of subsection (i)--authorizing the EPA to manage the transition toward non-HFC substitutes while ensuring that implementation is not unduly disruptive--and with general principles of administrative law.\113\ This interpretation also aligns best with the text and structure of subsection (i), which contemplates the remaining provisions of subsection (i) applying to rules creating restrictions: “the Administrator may by rule restrict, fully, partially, or on a graduated schedule, the use of a regulated substance in the sector or subsector in which the regulated substance is used.” \114\ The Agency therefore finds the best reading of the effective date provision in subsection (i)(6) as not restarting the one-year delay in effective date upon promulgation of the adjustments in this rulemaking that provide relief from existing restrictions originally promulgated in the 2023 Final Rule. The provision would still require a one-year delay in effective date for the creation of any new restrictions, whether in the sectors or subsectors covered by the 2023 Final Rule or otherwise, as that would be an “applicable rule” under subsection (i)(6).

\113\ Congress has long recognized in the Administrative Procedure Act, for example, the distinction between “a substantive rule” that “relieves a restriction” and one that does not for effective-date purposes. 5 U.S.C. 553(d)(1). See Indep. U.S. Tanker Owners Comm. v. Skinner, 884 F.2d 587 (D.C. Cir. 1989) (effective date requirement did not apply even when a waiting period would have benefited third parties).

\114\ See 42 U.S.C. 7675(i)(1) (emphasis added).

Since finalizing the 2023 Final Rule, the EPA has issued two rules under subsection (i) of the AIM Act that adjusted existing restrictions based on new information. In those rules, we made changes to the requirements under subsection (i), including extending compliance dates, at least one year before the restriction taking effect.\115\ To the extent those previous rules took a position to the contrary, the Agency has reconsidered its position and finds that the best reading of subsection (i)(6) is that the one-year clock begins upon promulgation of the “applicable rule” at issue, and does not begin again upon promulgation of a rule modifying existing restrictions that were originally promulgated under subsection (i) if those modifications provide relief from a restriction.

\115\ See 88 FR 88826 (December 26, 2023); 89 FR 100381 (December 12, 2024).

Comment: Commenters that addressed this provision were generally supportive of the EPA's proposal to raise the temperature threshold. Many commenters noted that this was a targeted change based on new data that properly differentiates low-temperature transport refrigeration equipment that has unique technical challenges from other equipment. One commenter indicated this adjustment is tailored, technically justified, and administratively sound. Another commenter described this change as a “technical tweak” that relaxes an overly stringent use condition and does not introduce any new restrictions.

Response: The EPA agrees with the commenters that supported the proposal for reasons that include it is tailored, technically justified, administratively sound, and a technical adjustment.

Comment: A few commenters disagreed with the Agency's proposal. One commenter suggested that the threshold be -40 [deg]C since intermodal containers that use compliant refrigerants at that temperature have been commercially available on the global market for more than a decade. This commenter also did not believe that there is a significant distinction between the temperature needs of deep frozen versus fresh and frozen cargo in the -35 [deg]C to -40 [deg]C range, and that most critical life sciences products such as blood plasma and pharmaceuticals require temperatures below -50 [deg]C. A few commenters who were generally opposed to any relaxing of the requirements of the 2023 Final Rule were opposed to changing the temperature threshold due to environmental impacts. One commenter suggested that relief could be time-limited. This commenter noted that if the relief is provided for the purpose of shipping critical materials, then the

reliable supply of refrigerant is also critical.

Response: The EPA disagrees with commenters who opposed changing the temperature threshold for refrigerated transport intermodal containers. These commenters did not provide technical information to counter the information cited in the proposed rule that demonstrated the need for a change given a lack of available refrigerants that would be effective at this low temperature range.

The EPA disagrees with the suggestion of a temporary change to this restriction as the Agency does not have information at this time indicating when an alternative will be available that would meet the limit established in the 2023 Final Rule which could meet the needs of intermodal refrigerated transport equipment in this temperature range. Given the transportation conditions necessary for shipping blood plasma, pharmaceuticals, temperature-sensitive enzymes, dangerous goods, and other materials at temperatures below -35 [deg]C, the EPA agrees to provide targeted relief. However, to the extent that alternatives are developed in the future, the Agency may consider a rulemaking to restrict the use of legacy refrigerants. The EPA also disagrees with one commenter's request to change the temperature threshold to -40 [deg]C. While this commenter indicated that there is not a significant distinction between the temperature needs of cargo in the -35 [deg]C to -40 [deg]C range, the commenter did not provide technical information to support the change, such as which refrigerant(s) or any supporting documentation. The lack of a distinction between -35 [deg]C and -40 [deg]C supports the Agency's decision.

The EPA also clarifies that the lowest temperature at which equipment is designed to operate determines whether it is subject to use restrictions. This means that if a refrigerated transport-- intermodal container is designed to achieve a box temperature below -35 [deg]C, it would not be subject to restrictions even if at times the container is operated at temperatures at or above -35 [deg]C.

Comment: Several commenters who addressed this provision in their comments confirmed that utilizing box temperature is the standard industry practice for designing, marketing, and selling refrigeration equipment used in intermodal refrigerated transport, and no commenter opposed the Agency's proposal to change the temperature measurement location.

Response: The EPA is finalizing the box temperature as the point of temperature measurement to better align with common industry practice.