 Its manufacture is now banned or severely restricted by the Montreal Protocol of August 1987 because of the damage that chlorofluorocarbons cause to the ozone layer if released into the atmosphere.One widely adopted replacement refrigerant is the hydrofluorocarbon (HFC) known as R-134a (1,1,1,2-tetrafluoroethane).Heat pumps using R-134a replaced R-12 (dichlorodifluoromethane) and have similar thermodynamic properties but with insignificant ozone depletion potential and a somewhat lower global warming potential.