The only refrigerants used as a replacement for R-12 is 134-A, it is a HFC freon. Thid does not destroy the ozone but it cannot not be vented. Other refrigerants claim they can be used. but the EPA has the final say. Go to the EPA website and check.
R-12 Depletion factor 1.0
Halons are much more damaging to the ozone.
R-22 will be phased out by the year 2030 (zero production)
Freon-12, which is basically the brand name under which the chemical compound called dichlorodifluoromethane is marketed, is a chlorofluorocarbon halomethane which serves as a refrigerant as well as an aerosol spray propellant. However, its production was ceased in the year 1995, owing to apprehensions regarding the damage to the ozone layer. Freon-12 is capable of depleting ozone up to 0.82 percent, which is considered to be comparatively high.
The presence of chlorofluorocarbons as an aerosol in medications, for instance Albuterol, has been gradually phased out by the US Food and Drug Administration. It has been substituted by hydroflouroalkane or HFA that does not cause any damage to the environment.
Freon-12 also used to be an element in automobiles manufactured before 1994, which can now be retrofitted by substituting it with another substance.
Alternative refrigerants which are being currently used as substitutes include: