Propane

• Propane is a three-carbon alkane with the molecular formula C3H8, normally a gas, but compressible to a transportable liquid. 
• A by-product of natural gas processing and petroleum refining, it is commonly used as a fuel for engines, oxy-gas torches, barbecues, portable stoves, and residential central heating.
• A mixture of propane and butane, used mainly as vehicle fuel, is commonly known as liquefied petroleum gas (LPG or LP gas). It may also contain small amounts of propylene and/or butylene. 
• All commercial propane fuels include an odorant, almost always ethanethiol, so that people can easily smell the gas in case of a leak.