EPA is cautioning homeowners, manufacturers of propane-based refrigerants, home improvement contractors and air conditioning technicians of the safety hazards related to the use of propane in existing motor vehicle and home air conditioning systems.

Number of refrigerants with “22a” or “R-22a” contain highly flammable hydrocarbons, such as propane. Using propane based refrigerant in an air conditioner that is not designed for flammable refrigerants poses a threat to homeowners as well as service technicians as the systems recharged with “22a” refrigerants can catch fire or explode resulting in injury and property damage.

EPA is investigating instances where propane-based refrigerants have been marketed and used as a substitutes for HCFC-22 (R-22) and will take enforcement actions where appropriate.

More information at http://www.epa.gov/ozone/snap/r22a.html