Synthetic chemical such as chlorofluorocarbon (CFC), chlorofluoromethane, or halon used in aerosol cans, plastic foams, refrigerants, and certain solvents. Although having non-reactive (inert) properties, these compounds undergo decomposition in the higher reaches of the atmosphere (stratosphere) due to sunlight. Resulting chlorine atoms catalyze the decomposition of the ozone gas causing wide 'holes' in the protective ozone layer, thus allowing harmful ultraviolet rays to reach earth's surface.