Bhopal Gas Tragedy was a gas leak incident which happened on the night of December 2, 1984 at the Union Carbide India Limited (UCIL) pesticide plant in Bhopal, Madhya Pradesh, India. It was a catastrophe that had no parallel in the world’s industrial history and is considered to be the world’s worst industrial disaster. 30 etric tonnes of toxic Methyl IsoCyanate (MIC) escaped from a large storage tank killing about 3800 people immediately, permanently disabling 17,000 and injuring 200,000.
In November 1984, most of the safety systems were not functioning at the Union Carbide India Limited (UCIL) pesticide plant and many valves and lines were in poor condition.Tank 610 contained 42 tons of MIC, more than safety rules allowed for. At 11.00 PM on December 2 1984, while most of the one million inhabitants of Bhopal slept, an operator at the plant observed a small leak of methyl isocyanate (MIC) gas and increasing pressure inside a storage tank. The vent-gas scrubber, a safety device designed to neutralize toxic discharge from the MIC system, had been turned off for the past three weeks. Apparently, a faulty valve had allowed one ton of water, which was used for cleaning internal pipes, to mix with 40 tons of MIC. A 30-ton refrigeration unit that normally served as a safety component to cool the MIC storage tank had been drained of its coolant for use in another part of the plant. Pressure and heat from the vigorous exothermic reaction in the tank started to build up. A runaway reaction started, which was accelerated by contaminants, high temperatures and also by the presence of iron from corroding non-stainless steel pipelines. The resulting exothermic reaction increased the temperature inside the tank to over 200 °C (392 °F) and raised the pressure. This forced the emergency venting of pressure from the MIC holding tank, releasing a large volume of toxic gases. At around 1.00 AM, December 3, loud rumbling reverberated around the plant as a safety valve gave way sending a plume of MIC gas into the early morning air.About 30 metric tons of MIC escaped from the tank into the atmosphere in 45 to 60 minutes. Within hours, the streets of Bhopal were littered with human corpses and the carcasses of buffaloes, cows, dogs and birds. An estimated 3,800 people died immediately, mostly in the poor slum colony adjacent to the UCC plant. This catastrophe happened because the essential safety systems either failed or were inoperable and the safety procedures were not strictly complied with.
The safety equipment used in the Bhopal plant were as follows:
- Vent Gas Scrubber (VGS): It was intended to neutralize the toxic release material released from various equipment of MIC plant. However, it was not capable of controlling the runaway reaction. (Further, it was not operational that night).
- Flare tower: It was designed to burn out excess Carbon Monoxide and MIC vapours at a controlled rate. It was not capable of burning the huge amounts released that night. (Further, it was under maintenance that night).
- MIC storage 30 tones refrigeration system: It was installed to keep the storage tank material below a temperature of 5o C. (However, the system had been shut down in May 1984 to save power, approx. $ 20 per day).
- Water spray: This could be used to knock out the toxic chemical vapour by spraying a large amount of water. But, while the toxic gases were released at 30 m (100 ft) above ground, the water spray could not reach that height and hence could not knock out any gas.
- Danger alarm (siren): Installed for warning the community people. However, it was switched off after 5 minutes as per the revised company policy. Thereafter, only the muted siren for the plant personnel was sounded. No plant person died due to the gas. If the loud alarm for the public had been sounded for long, many would have escaped before the gas overpowered them.
- Evacuation plan: It was only made for the plant personnel, not for the public.
Some other factors that seemed to be contributing to this catastrophe were:
- The information about the storage and management of hazardous and dangerous materials was not effectively available.
- The impact could have been reduced if the residents had been given information on how to behave in case of leakage and if they had been warned by the siren early in the leakage.
- Effects of the gas on humans and the treatment were not known.
- There was a lack of coordination between the factory management and the emergency services.
- There was an inadequacy of warning systems and related mock drills for such emergencies.
- Union Carbide probably had never estimated the ‘worst case scenario’.
- The plant maintenance practices seemed inadequate and inventory of vital replacements had depleted.
- The escape of some of the experienced engineers and operating personnel from the plant had affected safety.
- Economy measures, overriding safety concerns, implemented at the plant contributed to the disaster.
- Densely populated areas around the plant.
- The absence of a proper road network. Rescue workers had to move on foot through densely populated areas.
- Lack of effective emergency medical facilities.
- Inadequate transport for emergency evacuation.
- People sleeping on pavements/railway platforms.
Safety Measures to prevent such happenings
- The Administration and other essential services must know the location and exact nature of any hazardous chemicals that are stored by any industrial establishment.
- Safety standards and procedures should be strictly followed. Safety is more important than economic gain.
- Proper and periodic maintenance of the plant. Do not neglect even if the leak is very small.
- All the safety equipment should be checked periodically and make sure they are perfectly working.
- Periodic mock drills to be done to rehearse the steps to be taken in case of an unexpected accident.
- The people living in the neighbourhood should be made aware of: (i) The chemicals being stored. (ii) The possible symptoms and antidote. (iii) Emergency procedures, which should be practised. (iv) Nearest medical facilities. (v)contacting the factory management. (vi) Sources of transportation/ambulances for emergency evacuation. (vii) Make a chart of simple Dos and Don’ts in the event of a chemical disaster
- NGOs and other Voluntary Organizations skilled at providing help should be involved in the disaster management process and be listed and known to the administration as well as the residents of the neighbourhood.
- Residents living in the neighbourhood should also be trained with the emergency services.