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This means that breathing low concentrations of freon from a leaking refrigerator or air conditioner over a long period of time is unlikely to have a cumulative effect, and thus few, if any, long term health effects.
Where Good Neighbors and Good Servicemen Meet. Freon Leaks & Evaporator Coils. Refrigerant used for cooling has come to be known by DuPont's trade name which is Freon. My experience with Freon leaks has been entirely with refrigerants R-22 and R-12 used for household and automotive cooling.