Just went out to the barn and let a puff out of the r 12 a hot shot on a match it blew it out did it a second time it blew out. Quite possibly it is the oil that catches fire in a collision allthough i have had a towing company for forty years and most car crashes destroy the condenser and have only seen two or three fires in crashes in all my years in the business. The vehicel fire i see are catalic conveter on grass, fuel leaks , or an occisonal friction fire {insurance policy aginst payment book} Im not trying to say it not safe but if it is aginst any laws dont do it.