Propane — sometimes known as liquefied petroleum gas, or LPG — is a gas normally compressed and stored as a liquid. It is nontoxic, colorless, and virtually odorless; an identifying odor is added so it can be detected. Propane is commonly used for space and water heating, for cooking, and as fuel for engine applications such as forklifts, farm irrigation engines, fleet vehicles, and buses; however, its applications are rapidly growing due to new technology developments. When used as vehicle fuel, propane is known as propane autogas.