The US Environmental Protection Agency (EPA) is proposing to prohibit the use of certain chemicals that it said "significantly contribute to climate change," where safer, more climate-friendly alternatives exist.

It is the EPA's second action aimed at reducing emissions of hydrofluorocarbons (HFCs) under President Barack Obama's Climate Action Plan. The agency targets a reduction of greenhouse gases altogether by up to 42 million t of carbon dioxide equivalent by 2020.

"President Obama called on us to take action against potent greenhouse gases that contribute to climate change. Today, we are issuing a new proposal that builds on the innovative work businesses across the country have already made to reduce and replace some of the most harmful chemicals with safer, more climate-friendly alternatives that are available and on the market today," said EPA Administrator Gina McCarthy.

Under the authority of the Clean Air Act, EPA's Significant New Alternatives Policy (SNAP) Program evaluates substitute chemicals and technologies regarded as safe for the ozone layer. The latest proposals would change the status of certain high-global warming potential HFCs previously listed as acceptable to unacceptable in specific end-uses if lower risk alternatives are available.

The HFCs and HFC-containing blends affected by today's proposal are used in aerosols, motor vehicle air conditioning, retail food refrigeration and vending machines, and foam blowing.

Recently, EPA proposed to expand the list of climate-friendly alternatives for refrigeration and air conditioning under its SNAP Program after consultation with industry, environmental groups and other stakeholders.

This proposal also adds one lower-GWP HFC (HFC-32) that the agency said has just one-third the GWP of the conventional refrigerants currently being used in room air conditioning units. These refrigerants are already in use in many of these applications in Europe and Asia.

EPA will accept comment on its latest proposal for 60 days after publication in the Federal Register.