US EPA proposes long-awaited SNAP Rule #27
By Steve Schaeber, MACS Director of Training and Regulatory Affairs on 10/24/2025
On Friday, October 24, 2025, US EPA released the long-awaited proposed SNAP Rule #27.
This new rule proposes to list several substitutes as acceptable, subject to use conditions, in the refrigeration and air conditioning sector (which includes MVAC, motor vehicle air conditioning), list one substitute as acceptable, subject to use conditions, in the fire suppression sector, update use conditions for other multiple refrigerants, and propose two use condition options related to equipment certification or industry safety standard requirements for multiple refrigerants.
For motor vehicle air conditioning (MVAC), EPA proposes to list HFO-1234yf as acceptable in MVAC in new buses and heavy duty on-highway vehicles. It also proposes to list a number of refrigerant blends as acceptable as retrofits in certain MVAC applications, including R-444A, R-456A, R-452A, R-480A, and R-1234yf.
Here’s a link to EPA’s fact sheet on the proposed Rule #27: https://www.epa.gov/system/files/documents/2025-10/fact-sheet-snap-rule-27_0.pdf
Here’s a link to the pre-publication document for the proposed Rule #27 (it’s 176 pages): https://www.epa.gov/system/files/documents/2025-10/frl-12207-1-oar-snap-27-nprm-preamble-10222025_admin-prepub_0.pdf
And here’s a link to the proposed Rule #27 on EPA’s website: https://www.epa.gov/snap/regulations-proposed-rules-and-final-rules-determined-epa
MACS is the Mobile Air Climate Systems Association. We are the non-profit trade association representing manufacturers, distributors, service shops, technicians and educators in the mobile air conditioning and vehicle thermal management sectors.
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MACS is the largest provider of US EPA Section 609 Certification for technicians working on vehicle air conditioning, refrigerant and climate control systems. Get your MACS 609 Certification today on our website at https://macsmobileairclimate.org/about-609-certification/
Thanks for reading.
About the author: Steve Schaeber is director of training and regulatory affairs at MACS, the Mobile Air Climate Systems Association, where he engages with industry and government stakeholders.
Steve’s focus is on refrigerant lifecycle management in the mobile air conditioning and thermal management sector through training and best service practices, including the proper use of tools and equipment to recycle refrigerant and minimize its release into the atmosphere.
Steve serves as vice chairman of the SAE Interior Climate Control Service Committee, vice chairman of the SAE CDPC Cabin Disinfection Practices Committee and secretary of SAE HFTC6 Human Factors Technical Committee for off-highway construction and agricultural equipment.
You can reach Steve at sschaeber@macsmobileairclimate.org