As part of the Obama administration's Climate Action Program, the US Environmental Protection Agency (EPA) has expanded the list of Significant New Alternatives Policy (SNAP)-approved substitutes for the ozone-depleting substances and high-GWP hydrofluorocarbons (HFCs) used in refrigeration.

The substitutes have GWPs that range from 3 to 675 and can replace older compounds with GWPs ranging between 1400 and 4000.

EPA's move followed consultation with industry, environmental groups and others.

The agency's extended list includes ethane in very low temperature refrigeration and in non-mechanical heat transfer, isobutane in retail food refrigeration (stand-alone commercial refrigerators and freezers) and in vending machines as well as propane in household refrigerators, freezers, or combination refrigerators and freezers, in vending machines and room air conditioning units.

Additional substitutes approved include the hydrocarbon blend R-441A in retail food refrigeration (stand-alone commercial refrigerators and freezers), in vending machines and room air conditioning units, along with HFC-32 (difluoromethane) in room air conditioning units. HFC-32 has one-third the GWP of the conventional refrigerants currently being used in room air conditioning units, EPA says.

The agency points out that many of these refrigerants are already in use in many of these applications in Europe and Asia.

EPA is also exempting all of the listed climate-friendly alternatives except HFC-32 from the Clean Air Act venting prohibition, as it says current evidence suggests that their venting, release, or disposal does not pose a threat to the environment.