{"abstract":"Pursuant to the U.S. Environmental Protection Agency's Significant New Alternatives Policy program, this action proposes to list the refrigerant 2,3,3,3-tetrafluoropropene, also known as HFO- 1234yf, as acceptable, subject to use conditions, in the motor vehicle air conditioning end-use for retrofit of heavy-duty pickup trucks and complete heavy-duty vans. This action supplements the Agency's November 10, 2025, proposal with respect to the proposed listings in the motor vehicle air conditioning end-use for retrofit of heavy-duty pickup trucks and heavy-duty vans (both complete and incomplete vans). The EPA is also supplementing that proposal to clarify the intended scope of that proposed rule. The EPA is providing an opportunity for public comment on the additional listing and the clarification. The EPA is not reopening the comment period for any portions of the November 10, 2025, proposal which are not explicitly addressed in this supplemental proposal.","action":"Supplemental proposed rule.","agencies":[{"raw_name":"ENVIRONMENTAL PROTECTION AGENCY","name":"Environmental Protection Agency","id":145,"url":"https://www.federalregister.gov/agencies/environmental-protection-agency","json_url":"https://www.federalregister.gov/api/v1/agencies/145","parent_id":null,"slug":"environmental-protection-agency"}],"body_html_url":"https://www.federalregister.gov/documents/full_text/html/2026/04/06/2026-06665.html","cfr_references":[{"chapter":null,"citation_url":null,"part":"82","title":40}],"citation":"91 FR 17176","comment_url":null,"comments_close_on":"2026-05-06","correction_of":null,"corrections":[],"dates":"Comments on this supplemental proposal must be received on or before May 6, 2026 unless a public hearing is held. If a public hearing is held, comments on this supplemental proposal must be received on or before 30 days after the date of the public hearing. Public hearing: Any party requesting a public hearing must notify the contact listed in the FOR FURTHER INFORMATION CONTACT section, which is Emily Maruyama at email address: maruyama.emily@epa.gov by 5 p.m. Eastern Daylight Time on or before April 13, 2026. If a public hearing is held, it will take place on or around April 21, 2026. Please refer to the SUPPLEMENTARY INFORMATION section for additional information on the public hearing.","disposition_notes":null,"docket_ids":["EPA-HQ-OAR-2024-0503","FRL-12207-03-OAR"],"dockets":[{"supporting_documents":[{"title":"Risk Screen on Substitutes in Motor Vehicle Air Conditioning (Heavy-Duty Pickup Trucks and Complete Heavy-Duty Vans) (Retrofit Equipment); Substitute: HFO-1234yf (Solstice® yf or Solstice® 1234yf). (ICF, 2026b) - Supplemental Proposal","document_id":"EPA-HQ-OAR-2024-0503-0140"},{"title":"Proposed Regulatory Text for SNAP Rule 27 - Supplemental Proposal","document_id":"EPA-HQ-OAR-2024-0503-0139"},{"title":"Solstice Presentation to EPA 12-15-25 - Supplemental Proposal","document_id":"EPA-HQ-OAR-2024-0503-0136"},{"title":"SNAP Proposed Rule 27 Public Hearing Transcript","document_id":"EPA-HQ-OAR-2024-0503-0096"},{"title":"UL 60335-2-40- 4th Edition Standard for Safety Household and Similar Electrical Appliances - Safety - Part 2-40: Particular Requirements for Electrical Heat Pumps, Air-Conditioners and Dehumidifiers","document_id":"EPA-HQ-OAR-2024-0503-0080"},{"title":"UL 399, 2008. Standard for Safety--Drinking Water Coolers. 7th Edition","document_id":"EPA-HQ-OAR-2024-0503-0079"},{"title":"Removal of CBI claim for Gradient HDOH Risk Assessment Memo","document_id":"EPA-HQ-OAR-2024-0503-0075"},{"title":"Risk Screen on Substitutes in Residential and Light Commercial Air Conditioning and Heat Pumps Commercial Ice Machines (New Equipment); Substitute: R-457A (Forane® 457A). \n(ICF, 2025g)","document_id":"EPA-HQ-OAR-2024-0503-0072"},{"title":"Risk Screen on Substitutes in Motor Vehicle Air Conditioning (Buses) (New Equipment); Substitute: HFO-1234yf (Solstice® yf or Solstice® 1234yf). (ICF, 2025p)","document_id":"EPA-HQ-OAR-2024-0503-0065"},{"title":"Section IV.E Information on Refrigerants and Their Components – Residential and Light Commercial AC and Heat Pumps","document_id":"EPA-HQ-OAR-2024-0503-0063"}],"agency_name":"EPA","documents":[{"comment_count":7,"comment_start_date":"2026-04-06","updated_at":"2026-07-22T14:56:18.871-04:00","comment_url":"https://www.regulations.gov/commenton/EPA-HQ-OAR-2024-0503-0135","allow_late_comments":false,"id":"EPA-HQ-OAR-2024-0503-0135","comment_end_date":"2026-05-07","regulations_dot_gov_open_for_comment":false}],"supporting_documents_count":89,"id":"EPA-HQ-OAR-2024-0503","title":"Protection of Stratospheric Ozone: Listing of Substitutes under the Significant New Alternatives Policy Program in Refrigeration and Air Conditioning and Fire Suppression"}],"document_number":"2026-06665","effective_on":null,"end_page":17186,"executive_order_notes":null,"executive_order_number":null,"full_text_xml_url":"https://www.federalregister.gov/documents/full_text/xml/2026/04/06/2026-06665.xml","html_url":"https://www.federalregister.gov/documents/2026/04/06/2026-06665/protection-of-stratospheric-ozone-listing-of-substitutes-under-the-significant-new-alternatives","images":{},"images_metadata":{},"json_url":"https://www.federalregister.gov/api/v1/documents/2026-06665?publication_date=2026-04-06","mods_url":"https://www.govinfo.gov/metadata/granule/FR-2026-04-06/2026-06665/mods.xml","not_received_for_publication":null,"page_length":11,"page_views":{"count":1150,"last_updated":"2026-07-26 16:15:03 -0400"},"pdf_url":"https://www.govinfo.gov/content/pkg/FR-2026-04-06/pdf/2026-06665.pdf","presidential_document_number":null,"proclamation_number":null,"public_inspection_pdf_url":"https://public-inspection.federalregister.gov/2026-06665.pdf?1775220319","publication_date":"2026-04-06","raw_text_url":"https://www.federalregister.gov/documents/full_text/text/2026/04/06/2026-06665.txt","regulation_id_number_info":{"2060-AW45":{"issue":"202504","html_url":"https://www.federalregister.gov/regulations/2060-AW45/protection-of-stratospheric-ozone-new-and-updated-listings-for-refrigeration-and-air-conditioning","title":"Protection of Stratospheric Ozone: New and Updated Listings for Refrigeration and Air Conditioning","xml_url":"http://www.reginfo.gov/public/do/eAgendaViewRule?pubId=202504&RIN=2060-AW45&operation=OPERATION_EXPORT_XML","priority_category":"Substantive, Nonsignificant"}},"regulation_id_numbers":["2060-AW45"],"regulations_dot_gov_info":{"supporting_documents":[{"title":"Risk Screen on Substitutes in Motor Vehicle Air Conditioning (Heavy-Duty Pickup Trucks and Complete Heavy-Duty Vans) (Retrofit Equipment); Substitute: HFO-1234yf (Solstice® yf or Solstice® 1234yf). (ICF, 2026b) - Supplemental Proposal","document_id":"EPA-HQ-OAR-2024-0503-0140"},{"title":"Proposed Regulatory Text for SNAP Rule 27 - Supplemental Proposal","document_id":"EPA-HQ-OAR-2024-0503-0139"},{"title":"Solstice Presentation to EPA 12-15-25 - Supplemental Proposal","document_id":"EPA-HQ-OAR-2024-0503-0136"},{"title":"SNAP Proposed Rule 27 Public Hearing Transcript","document_id":"EPA-HQ-OAR-2024-0503-0096"},{"title":"UL 60335-2-40- 4th Edition Standard for Safety Household and Similar Electrical Appliances - Safety - Part 2-40: Particular Requirements for Electrical Heat Pumps, Air-Conditioners and Dehumidifiers","document_id":"EPA-HQ-OAR-2024-0503-0080"},{"title":"UL 399, 2008. Standard for Safety--Drinking Water Coolers. 7th Edition","document_id":"EPA-HQ-OAR-2024-0503-0079"},{"title":"Removal of CBI claim for Gradient HDOH Risk Assessment Memo","document_id":"EPA-HQ-OAR-2024-0503-0075"},{"title":"Risk Screen on Substitutes in Residential and Light Commercial Air Conditioning and Heat Pumps Commercial Ice Machines (New Equipment); Substitute: R-457A (Forane® 457A). \n(ICF, 2025g)","document_id":"EPA-HQ-OAR-2024-0503-0072"},{"title":"Risk Screen on Substitutes in Motor Vehicle Air Conditioning (Buses) (New Equipment); Substitute: HFO-1234yf (Solstice® yf or Solstice® 1234yf). (ICF, 2025p)","document_id":"EPA-HQ-OAR-2024-0503-0065"},{"title":"Section IV.E Information on Refrigerants and Their Components – Residential and Light Commercial AC and Heat Pumps","document_id":"EPA-HQ-OAR-2024-0503-0063"}],"regulatory_plan":{"html_url":"https://www.federalregister.gov/regulations/2060-AW45/protection-of-stratospheric-ozone-new-and-updated-listings-for-refrigeration-and-air-conditioning","title":"Protection of Stratospheric Ozone: New and Updated Listings for Refrigeration and Air Conditioning"},"comments_count":7,"agency_id":"EPA","comments_url":"https://www.regulations.gov/docketBrowser?rpp=50&so=DESC&sb=postedDate&po=0&dct=PS&D=EPA-HQ-OAR-2024-0503","supporting_documents_count":89,"docket_id":"EPA-HQ-OAR-2024-0503","document_id":"EPA-HQ-OAR-2024-0503-0135","regulation_id_number":"2060-AW45","title":"Protection of Stratospheric Ozone: Listing of Substitutes under the Significant New Alternatives Policy Program in Refrigeration and Air Conditioning and Fire Suppression","checked_regulationsdotgov_at":"2026-07-23T21:55:04Z"},"regulations_dot_gov_url":null,"significant":false,"signing_date":null,"start_page":17176,"subtype":null,"title":"Protection of Stratospheric Ozone: Listing of Substitutes Under the Significant New Alternatives Policy Program in Refrigeration and Air Conditioning and Fire Suppression; Supplemental Notice of Proposed Rulemaking","toc_doc":"Listing of Substitutes under the Significant New Alternatives Policy Program in Refrigeration and Air Conditioning and Fire Suppression","toc_subject":"Protection of Stratospheric Ozone","topics":["Administrative practice and procedure","Air pollution control","Chemicals","Environmental protection"],"type":"Proposed Rule","volume":91}