Mercaptan

Dictionary of Environmental Health

A generic term used to describe one of a number of toxic substances containing sulphur that have an unpleasant odour, sometimes described as that of rotting cabbage. They are produced naturally as part of the process of the decay of organic matter and are produced as by-products of some industrial processes.

Mercaptans are a contaminant of PETROLEUM but they are usually removed by the refining process. Mercaptan is sometimes added at very low concentrations to both natural gas and to LPG to provide a warning mechanism in case of leakage. These substances are also sometimes known as thiols.