Refrigerants R-11, R-12, and R-22, which are hydrochlorofluorocarbons (HCFCs) or chlorofluorocarbons (CFCs), contribute to the thinning of the ozone layer. Due to their negative effects on the environment, they are being phased out under international legislation from their widespread use in air conditioning and refrigeration systems. They are being replaced by substitutes like hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs).
