Propane smells like rotten eggs, a skunk’s spray, or a dead animal. Propane manufacturers add this smell to help alert customers to propane leaks. Some people may have difficulty smelling propane due to their age (older people may have a less sensitive sense of smell); a medical condition; or the effects of medication, alcohol, tobacco, or drugs. Consider purchasing a propane gas detector as an additional measure of security.
Odor fade is an unintentional reduction in the concentration of the odor of propane, making it more difficult to smell. Although rare, this can be caused by the presence of air, water, or rust in the cylinder. New and reconditioned small cylinders that sit too long before being filled are prone to internal rust when moisture and air get inside.