Propane (also called LPG-liquefied petroleum gas or LP Gas) is a liquid fuel stored under pressure. In most systems, propane is vaporized to a gas before it leaves the tank. Propane is odorless so manufacturers add an odorant to propane to help alert customers to propane leaks. The odorant smells like rotten eggs, a skunk’s spray or a dead animal to alert you that there may be a need for concern. For safety information, click here.