Two men cleaning a tank at the Metrowater sewage treatment plant in Kodungaiyur died of asphyxiation on Saturday. Their co-worker is battling for life in a hospital.
The incident took place around 3.30 a.m. at the Metrowater treatment plant on Manali High Road, Selaivoyal in Kodungaiyur when four contract workers tried to operate a valve to separate sludge from sewage in a tank, which is over six feet deep.
The two workers — Nanda Kumar (24) of Kadumpadi Amman Koil Street, Kodungaiyur and Jayakumar (28) of Subramanian Street, Vyasarpadi — were struck by poisonous gas inside the tank. “The two died on the spot and their co-workers Sathyaraj (26) and Raju (25), both residents of Kodungaiyur, attempted to retrieve their bodies. But Sathyaraj was knocked unconscious by the toxic gas while Raju managed to escape,” said an officer.
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Raju and the workers at the substation rushed Sathyaraj to the Government Stanley Hospital. He is in a critical condition, the officer added.
Manali police probed the accident and registered a case under Section 304A (causing death by negligence) of IPC and arrested the supervisor Shyamsundar (42) and manager Bhagyaraj (28), both residents of Tiruvottiyur. They were later released on bail.
Jayakumar was married with two children, while Nanda Kumar was a bachelor. In a statement, Chennai Metrowater said of the three sewage treatment plants functioning on the premises, one is being maintained by a contractor VA Tech Wabag.
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Action would be taken after an inquiry into cause of the accident. Of the 10 facilities, Metrowater has outsourced operation and maintenance of six treatment plants.
Sources in Metrowater said the system to draw sludge and transport it to another sump is operated through an extension from outside the tank. But, as the spindle rod of the valve located inside the tank broke, the workers had entered the tank and were struck by water and gas gushing from the valve chamber.