Natural gas itself is a colorless, odorless gas, so odorants are added to ensure that gas leaks are easily detectable. Often, the odorants are organic sulfur compounds such as dimethyl sulfide, methyl ethyl sulfide, isopropyl mercaptan, tert-butyl mercaptan, or tetrahydrathiophene (THT). The exact odorant or mixture of odorants may vary according to the safety regulations of the region where the gas is consumed.

Some applications require that the odorant be removed from the natural gas. For example, if natural gas is to be transferred to a different regulatory region, the odorant may need to be removed before the gas can enter the transmission pipeline. Catalytic processes that use commercial natural gas as a feedstock often require that the odorants be removed to prevent poisoning the catalyst. The odorant is usually present in low concentrations and treating large volumes of gas can be challenging.