Following the recent incident where three workers died after inhaling poisonous gases while cleaning sewerage in Faridabad, the Haryana Government has issued instructions regarding the safety measures to be taken and the equipment required for the operation and maintenance staff employed on sewerage system in the State.
“Manual entry in the sewer lines or manholes should be avoided. However, in case of unavoidable circumstances where manual entry is required, it should be ensured that all necessary precautions are taken,” said a spokesman of the Public Health Engineering Department.
Wherever operation and maintenance of sewerage system is handed over to contractor or agencies, an undertaking should be taken from them that they would follow all precautions. Such undertaking must be got signed from the contractor or agency at the time of allotment of work, said he.
Referring to the precautions to be taken by workmen against gas hazards, the spokesman said while entering a sewer or a manhole for cleaning or clearing an obstruction, efficient ventilation should be maintained, either natural or forced, and it should be ensured that the atmosphere inside the manhole of sewer has sufficient oxygen, and is free from toxic gases or vapours.
Apart from this, no smoking or open flames should be allowed nearby as methane gas is highly inflammable. Only safe and explosion-proof electric lighting equipment or mirrors for reflection of light should be used.
The instructions further said, “The atmosphere should be tested for toxic gases and oxygen deficiency, and, if the atmosphere is normal, the worker or sewer man may enter into the manhole or sewer with safety harness attached with two men standing at the top.”
The spokesman said if any toxic gas or oxygen deficiency is found, forced ventilation should be resorted by using a portable blower. Frequent tests should be confirmed even if the initial test is satisfactory, as conditions may change during the period workers are inside the manhole or sewers, as toxic gases may be trapped inside some hidden pockets in the sewer.
Only personnel experienced in the task and familiar with the dangers involved in working in toxic gas environment and fully equipped with proper protective safety equipment should be allowed to enter, he said.
Since the personnel working in sewerage maintenance systems were prone to infections, necessary precautions should be taken. Emergency first aid treatment kits should be provided to take care of minor injuries like cuts and burns. Also, the workers should be educated about the hazards of waterborne diseases such as typhoid and cholera through sewage and tetanus through cuts and wounds, said the spokesman.
Use of rubber gloves and gum boots should be insisted so that sewage or sludge does not come into direct contact with hands and feet of the sewer men. Also, various kinds of safety equipment is required in sewer maintenance work. These include breathing apparatus, gas mask, portable lighting equipment, non sparking tools, portable air blowers, rubber boots, safety belts and inhalers, he added.