Liquefied petroleum gas (LPG) is a fuel gas that contains a flammable mixture of hydrocarbon gases, specifically propane, propylene, butylene, isobutane, and n-butane. LPG is used as a fuel gas in heating appliances, cooking equipment, and vehicles. It is also used as an aerosol propellant and a refrigerant, replacing chlorofluorocarbons in an effort to reduce damage to the ozone layer. LPG is primarily obtained from natural gas and oil production but is also produced increasingly from renewable sources. Propane and butane are the two main types of LPG, and they are often mixed to get the best energy yields. LPG is commonly used in the agriculture industry for hot water for dairy operations, crops and produce drying, and other applications.