Liquefied petroleum gas. Is fired with a number of carbon atoms than methane. Basically, it is a gas, propane (C3 H8) and butane (C4 H10) commingle. The mixture is compressed into steel cylinders under high pressure, change the status of a fluid. Most liquefied petroleum gas will be used as a fuel in the household is also called LPG. Typically, propane gas and butane are colorless and odorless. But safety has to be down chemical smells. Will know when the gas leaked. In addition to household LPG gas. Also used as fuel in the car as well.