Any of a number of organic compounds analogous to hydrocarbons in which one or more hydrogen atoms are
replaced by fluorine. Once used in the United States as a propellant for domestic aerosols, they are now found
mainly in coolants and some industrial processes. FCs containing chlorine are called chlorofluorocarbons
(CFCs). They are believed to be modifying the ozone layer in the stratosphere, thereby allowing more harmful
solar radiation to reach the Earth's surface.