Methyl mercaptan

Formula: CH₄S | CAS: 74-93-1

Methyl mercaptan detection: Methyl mercaptan is highly irritant when it contacts moist tissues such as the eyes, skin, and upper respiratory tract. It can also induce headache, dizziness, nausea, vomiting, coma, and death. Ingestion of methyl mercaptan is unlikely since it is a gas at ambient temperatures.

Methyl mercaptan detection, routes of exposure

Inhalation
Inhalation is the major route of exposure to methyl mercaptan. An odour threshold of 0.002 ppm has been reported for methyl mercaptan, but olfactory fatigue may occur and thus, it may not provide adequate warning of hazardous concentrations. Vapours of liquified methyl mercaptan gas are heavier than air and spread along the ground. Exposure in poorly ventilated, enclosed, or low-lying areas can result in asphyxiation.

Other routes of exposure come from Skin/Eye contact and Ingestion.

At room temperature (above 43°F), methyl mercaptan is a colourless gas with an unpleasant odour described as rotten cabbage. It is slightly soluble in water. It is generally shipped as a liquified compressed gas. When heated to decomposition, it emits toxic fumes, such as sulfur dioxide, and flammable vapours. Methyl mercaptan should be stored in cool, well ventilated places. The main toxic effect of exposure to methyl mercaptan is irritation of the respiratory airway, skin, and eyes.
– Agency for Toxic Substances & Disease Registry

Why do we use methyl mercaptan?

Methyl mercaptan is mainly used to produce methionine, which is used as a dietary supplement for poultry and animal feed. Methyl mercaptan also is used in industrial applications as an intermediate in the production of pesticides, fungicides, plastics and animal feed additives. As an industrial intermediate, the chemical is reacted into something else or fully consumed to make the product.