Hydrogen Sulfide
Hydrogen sulfide is a inorganic compound expressed by the chemical formula H2S.
It is a chemical compound characterized by the foul odor of rotten eggs. Classified as malodorous substances based on the Offensive Odor Control Act, and is also generated in excrement, organic material garbage, and tobacco.
It can be noticed at very low concentrations as 0.0005ppm. However, at a high concentrations is very toxic causing instantaneous death at 1,000ppm (0.1%) or higher.
Hydrogen sulfide is generated as a result of the volcanic activity, petrochemical plants work, sewage processing plants, and waste treatment plants. Also is generated by the metabolic activity of anaerobic bacteria.