USA: The US Environmental Protection Agency (EPA) has warned against the illegal use of hydrocarbon refrigerants in domestic air conditioning.

The EPA warns that home air conditioning systems are not designed to handle propane or other similar flammable refrigerants.

'The use of these substances poses a potential fire or explosion hazard for homeowners and service technicians,' it says.

The EPA is currently investigating instances where propane has been marketed and used as a substitute for R22.

'EPA is aware of incidents that have occurred both overseas and in the US where individuals have been injured as a result of the use of propane and other unapproved refrigerants in air conditioning systems. We are investigating and will take enforcement actions where appropriate.'

The EPA points out that, as well as being sold as R290, these unapproved refrigerants are also sold as 22a, 22-A, R-22a, HC-22a, and CARE 40.

'At this time, EPA has not approved the use of propane refrigerant or other hydrocarbon refrigerants in any type of air conditioner,' says a statement from the agency. 'Homeowners and technicians are strongly recommended to limit use of propane or other hydrocarbons to only those appliances specifically designed for these substances and that are properly marked to alert technicians that the equipment contains a flammable substance.'

In the US, propane has been approved as a substitute refrigerant for R22 in industrial process refrigeration systems and in new, stand-alone retail food refrigerators and freezers that are specifically designed to use flammable hydrocarbon refrigerants.