Originally Posted by Jake_J
I've used it before, not the Envirosafe brand but Duracool and Emzone. Envirosafe or any R12a or 12a refrigerant is a hydrocarbon mix of propane and isobutane that can be used in place of the banned R12 (that destroys the ozone layer) or the current R134a. It's very popular here in Canada because the way the laws are written regarding R134a mean that only people in the industry can have access to R134a at a reasonable cost. In the US anybody can go into Walmart and get a can or two of R134 for 6 bucks each so there's not much of a market for R12a. R12a is not illegal in the US as a whole, it's legal in most states but several states don't allow it because of the flammability concerns. In reality it's quite safe, hydrocarbon refrigerants are used all over the world and not just in cars. A typical car will take about a small 6oz charge of R12a which while it is more flammable than R134a, it's sealed in a system in the engine compartment and in reality even R134a will burn with enough heat and pressure. Also if you're worried about the fire hazard of a few ounces of hydrocarbon gas then you probably should be extremely worried about the many gallons of hydrocarbons you have in the gas tank.
First, R12A is not legal here in the US and companies have been required to stop selling it. EPA regulations prohibit replacing ozone depleting refrigerants with flammable refrigerants, but the EPA doesn't prohibit the use of flammable refrigerants in motor vehicle AC systems designed for 134A. This is why R12A is no longer sold here but flammable R134A replacements are readily available. Both R12A and R134A replacements are typically a 60/40 blend of propane and isobutane respectively.
Second, 6 ounces of flammable gas is more than enough to blow a car up if the evaporator dumps the entire charge into the cabin of the vehicle and it is ignited by a spark, although the odds of this happening are quite low. Also, comparing the fuel in a vehicle's tank to the refrigerant in the AC system is not a good comparison since the fuel tank and lines are well protected from collision damage, not right in front of the vehicle like the condenser is. Also, the fuel doesn't run through the interior of the vehicle like the refrigerant does. The condenser is quite likely to be damaged in a minor front end collision since it is right in front of the vehicle and this could release refrigerant and cause a fire, although the occupants in the vehicle probably aren't likely to be burned to death since they are behind the firewall.
Not that I am saying people shouldn't use flammable refrigerants if they want to, I am just informing people of the risks and benefits so they can make an informed decision on what refrigerant they want to use.