The U.S. Environmental Protection Agency (EPA) on March 29 proposed to expand the list of acceptable substitutes and prohibit the use of certain chemicals in the United States that significantly contribute to climate change where safer, more climate-friendly alternatives exist.

This is another step forward in a series under President Obama's Climate Action Plan, which aims to reduce emissions of hydrofluorocarbons (HFCs). The emissions avoided from this proposed rule are estimated to be up to 11 million metric tons of carbon dioxide equivalent in 2030, which is equal to the emissions from the energy used by approximately one million homes for one year.

“This new proposal would reduce the use and emissions of some of the most harmful HFCs, which are thousands of times more potent than carbon dioxide, and approves safer, more climate-friendly alternatives to protect public health and our environment,” said EPA Administrator Gina McCarthy. “In support of President Obama’s Climate Action Plan, this action will not only result in significant reductions of harmful greenhouse gases, but it expands the options for safer alternatives available on the market.”

EPA is both proposing to expand the agency’s Significant New Alternatives Policy (SNAP) Program list of climate-friendly alternatives and, now that safer options are available, proposing to change the status of certain higher-global warming potential (GWP) substances that were previously listed as acceptable. In developing this proposal, the agency received input from industry, environmental groups, and others through workshops and meetings over the past year.

EPA’s proposal includes:

• Listing as acceptable, subject to conditions to ensure safe use, propane and HFO-1234yf in specific end-uses in the refrigeration and air conditioning sector.

• Listing as unacceptable certain flammable hydrocarbon (HC) refrigerants and HC blends for retrofitting existing residential central air conditioning equipment that was designed for non-flammable refrigerants. 

• Listing as unacceptable propylene and the HC blend R-443A in specific end-uses in the refrigeration and air conditioning sector.

• Modifying the listing status for certain high-GWP alternatives for certain end-uses in refrigeration and air conditioning such as chillers and household refrigerators.

This latest proposal builds on EPA’s July 2015 SNAP final rule prohibiting certain HFCs in the aerosols, foams, and refrigeration and air conditioning sectors. EPA will accept comment on the proposal for 45 days after publication in the Federal Register. To read the proposal (Rule 21) in its entirety, visit