This papercraft designed by Rino Liha. Liquefied petroleum gas (also called LPG, GPL, LP Gas, or autogas) is a flammable mixture of hydrocarbon gases used as a fuel in heating appliances and vehicles. It is increasingly used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. Varieties of LPG bought and sold include mixes that are primarily propane, mixes that are primarily butane, and - most common - mixes including both propane C3H8 and butane C4H10, depending on the season — in winter more propane, in summer more butane. Propylene and butylenes are usually also present in small concentration. A powerful odorant, ethanethiol, is added so that leaks can be detected easily. The international standard is EN 589. In the United States, thiophene or amyl mercaptan are also approved odorants.