Chlorofluorocarbon (CFC) is a type of compound consisting of chlorine, fluorine, and carbon. CFCs are are man-made, stable, and non-toxic chemicals commonly used as refrigerants, solvents, aerosol propellants, and foam blowing agents. The most common CFCs are CFC-11, CFC-12, CFC-113, CFC-114, and CFC-115, and they are often referred to by the brand name Freon.
CFCs are very stable in the troposphere. They move to the stratosphere and are broken down by strong ultraviolet light, where they release chlorine radicals that act as a catalyst in the breakdown of ozone into oxygen.
In 1984, scientists discovered CFCs to be one cause of the depletion of the ozone layer, which acts as a filter for ultraviolet radiation from the sun. Because of this, many nations signed the Montreal-London Protocol. This treaty called for the production of CFCs to be stopped by the year 2000 for industrialized countries and the year 2010 for developing countries. The United States stopped production of CFCs in 1995, and alternate chemicals are used in their place.
The ozone depletion potential (ODP) for CFC-11, -12, -113, -114, and -115 is, respectively, 1, 1, 0.8, 1, and 0.6.