The US EPA has issued a safety warning regarding the use of flammable refrigerants in car and home air conditioning equipment.
A number of such refrigerant, called 22a or R-22a, are indeed labeled with a confusing name since they contain hydrocarbons such as propane – and not HCFC-22 (R-22), as they are being marketed to recharge existing air conditioning equipment not designed for flammable refrigerants.
These refrigerants have neither been submitted nor approved by EPA, who warns that this situation poses a threat to homeowners and to service technicians because the systems can catch fire and even explode.
In addition, EPA reminds that it has not found acceptable any flammable hydrocarbon refrigerants for use in existing air conditioning systems designed for use with HCFC-22. Use of flammables as a retrofit in equipment that was designed for nonflammable materials presents risks to consumers, to the equipment, and to service technicians who may not be prepared for handling flammable refrigerants.
EFCTC Note : such accidents already occurred in New Zealand
Source: US EPA