The United Nations Environmental Programme (UNEP) has been addressing the issue of the effect that clorofluorocarbons (CFCs) have on the ozone layer since 1977. CFCs have applications in foams, air conditioners, solvents, fire extinguishers, aerosol cans and refrigerators but substitues have been found. The Montreal Protocol on substances that deplete the ozone layer was agreed to by governments in 1987 (with minor amendments in 1990 in London and 1992 in Copenhagen.) The protocol aims to reduce and (by 2010) eliminate the emissions of man-made ozone depleting substances. There are now 161 countries complying with the Montreal Protocol. To learn more, perfrom a web search for "UNEP" or "Montreal Protocol"