Close Authorship The U.S. Environmental Protection Agency is moving to eliminate a class of chemicals widely used as coolants in refrigerators, air conditioners and heat pumps. If that feels like déjà vu, it should. These chemicals, called hydrofluorocarbons, or HFCs, were commercialized in the 1990s as a replacement for earlier refrigerants that were based on chlorofluorocarbons, or CFCs. CFCs were destroying the ozone layer high in the Earth’s atmosphere, which is essential for protecting life from the sun’s harmful ultraviolet radiation. HFCs are much less harmful than CFCs, but they create another problem — they have a strong heat-trapping effect that is contributing to global warming.