Liquefied petroleum gas (LPG)
In addition to compressed natural gas (CNG), the government also allows other alternative fuels to gasoline, including liquefied petroleum gas (LPG).
LPG used as an automotive fuel automotive must comply with the specification . This specification regulates six properties for LPG, including density, vapor pressure, copper strip corrosion, volatility, propane and butane mole percent. Of these, the specification sets a minimum mole percent for propane at 30% mol and butane at 60% mol.