Introduction :- Hydrogen sulphide is a colourless gas that has a sweet taste and a strong odour resembling that of rotten eggs. Hydrogen sulphide is produced from the deterioration of organic materials and is a naturally occurring seam gas is some coal and shale deposits. It can be detected by smell at small concentrations as low as 1ppm but this is unreliable as a warning characteristic as nasal sensitivity decreases with exposure and increased concentration levels. Hydrogen sulphide is a highly toxic gas that irritates the mucous membranes and eyes and has narcotic effect on the nervous system. The gas acts on the nervous system causing headache, dizziness, excitement and staggering walk. Massive acute exposure levels produce anoxia (absence of oxygen in Aertrial blood and tissues ) resulting in death. Exposure to concentrations greater than 500ppm can be fatal. Excessive exposure is often characterised by depression at low concentrations, then stimulation, followed ...