What makes gas smell?

Gas has been given a very recognisable odour for safety reasons, to ensure that gas leaks can be easily detected and to prevent risks of explosion and asphyxia. This smell is that of TetraHydroThiophene, or THT, a gas added in very small amounts to marketed natural gas.

Odorisation occurs when the gas is injected into the French transport grid. As a Transport Grid Manager (GRT), Teréga is responsible for performing this odorisation when it injects gas drawn off its stores, or biomethane produced in a methanisation unit connected to the grid.