A Series Case Reports of Four Accidental Sewer Gas Poisoning

Sewer gas (H2S) is a toxic gas generally produced naturally by decaying organic matter. Death in sewer gas poisoning is due to respiratory arrest. Acute exposure of Hydrogen sulphide causes cytochrome oxidase enzyme inhibition causing disruption of oxidative metabolism and affecting nervous system and cardiac tissue immediately. It affects almost all system like, CNS, respiratory, cardiovascular, renal, gastrointestinal, dermal and ocular system. The powerful effect of hydrogen sulphide over olfactory inhibition makes the people unaware to its characteristic rotten egg odour. Rarely hydrogen sulphide poisoning occurs by intention but most of the case is accidental. Hydrogen sulphide is highly toxic and flammable gas, and, because of heavier than air it is accumulated at the bottom of poorly ventilated and closed space. In India it is observed that most of the sewer cleaning is done manually and the workers are not aware to its harmful effect because of lack of knowledge, so they unfortunately comes under its silent dangerous effect. There are standards and guidelines for exposure of hydrogen sulphide at work place; if it is followed and proper safety measures are taken then incidence will be reduced. Here we are reporting a series of four cases of accidental sewer gas poisoning, the autopsy of which were done in our mortuary, AIIMS, New Delhi.