Hydrochlorofluorocarbons (HCFC) are petroleum by-products used as refrigerants in air conditioning units and in the manufacture of synthetic insulation materials. Since 1995 these substances have replaced chlorofluorocarbons (CFC) which were proved to be responsible for the depletion of the ozone layer. Although they are much less polluting, HCFCs are still harmful to the environment. Therefore, according to the Montreal protocol, the developed countries must replace them in turn within the next twenty years. Replacements are currently under study.
The chlorine load in the stratosphere - Scientific assessment of the ozone layer depletion. Source www.arap.org