Liquefied petroleum gas or liquid petroleum gas (LPG or LP gas), is a mixture of propane and butane in the ratio of (30:70). LPG is a flammable hydrocarbon gases used as fuel in heating appliances, cooking equipment, 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. When specifically used as a vehicle fuel it is often referred to as auto gas.
Varieties of LPG bought and sold include mixes that are primarily propane (C3H8), primarily butane (C4H10) and, most commonly, mixes including both propane and butane.