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Unacceptable Substitute Refrigerants

Substitutes are reviewed on the basis of ozone depletion potential, global warming potential, toxicity, flammability, and exposure potential. Lists of acceptable and unacceptable substitutes are updated several times each year. A chronological list of SNAP updates is also available.

Note: SNAP Notices and Final Rules published in the Federal Register take precedence over all information on the web site.
Unacceptable Substitutes for ODS in Refrigeration and Air Conditioning
Substitute (Name Used in the Federal Register) ODS Being Replaced End-uses Reason
All flammable refrigerants, including OZ-12® (Hydrocarbon Blend A), HC-12a® (Hydrocarbon Blend B), and Duracool 12a except HFC-152a in new MVACs CFC-12 Motor vehicle air conditioning, retrofit and new Lack of adequate assessment that characterizes incremental flammability risk
OZ-12® (Hydrocarbon Blend A), HC-12a® (Hydrocarbon Blend B), and Duracool 12a CFC-12 All end-uses other than industrial process refrigeration, retrofit and new Lack of adequate assessment that characterizes incremental flammability risk
R-141b CFC-11 centrifugal chillers, new High ODP; other substitutes with lower overall risk have been identified
R-176
(R-176 contains CFC-12, HCFC-22, and HCFC-142b. It is a different product from RB-276, typically sold under the name "Free Zone.")
CFC-12 All end-uses, retrofit and new Contains CFC-12
R-403B R-502 All end-uses, retrofit and new Contains a perfluorocarbon that exhibits extremely high GWP and very long lifetime
R-405A CFC-12 All end-uses, retrofit and new Contains a perfluorocarbon that exhibits extremely high GWP and very long lifetime
MT-31 all CFCs and HCFCs All end-uses, retrofit and new Toxicity of a constituent
Hexafluropropylene (HFP) and blends containing it all CFCs and HCFCs All end-uses, retrofit and new HFP is toxic
NARM-22 HCFC-22 All end-uses, retrofit and new Contains HCFC-22
Self-Chilling Cans using HFC-134a or HFC-152a CFC-12, HCFC-22, R-502 Household Refrigeration, Transport Refrigeration, Vending Machines, Cold Storage Warehouses and Retail Food Refrigeration; retrofit and new Unacceptably high greenhouse gas emissions from direct release of refrigerant to the atmosphere

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