A method of reducing or eliminating the flammability of a refrigerant to be used as the working fluid in a vapor compression refrigerator, air conditioner, or heat pump, wherein said refrigerant comprises at least one component selected from the group consisting of hydrocarbons, hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs or FCs), and ammonia (NH.sub.3), said method comprising the steps of:
- a) providing an additive comprising at least one compound selected from the group consisting of bromine-containing alkenes and bromine-containing alcohols, all of which also contain another halogen, and
- b) mixing said additive with said refrigerant to form a mixture containing between 0.1 and 20 percent by weight of said additive.