Lessons learned 30 years after the Bhopal disaster: a new safety culture

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30 years have passed since the terrible disaster in Bhopal, which occurred on December 3, 1984 in the region of Bhopal (India).

The accident was caused by a leak of methyl isocyanate (MIC) at a pesticide plant owned by US company Union Carbide.


There are multiple theories and possible causes of the accident, though the main theory that emerges from research conducted by Union Carbide and the Indian justice is that the accident was caused by not taking the proper precautions during cleaning and maintenance of the plant, which made the water pressure used, sodium chloride crystals, metallic debris and other impurities come into contact with the stored gas, initiating an exothermic reaction that caused the opening of the safety valves for the tanks due to overpressure and thus releasing toxic gas into the atmosphere; with the aggravating circumstance that the tank cooling system and the prior catalyst of gases released in the atmosphere, were disabled because of cost savings.

Upon contact with the atmosphere, the released compound began to decompose several highly toxic gases that formed a lethal cloud. Since they were gases that were denser than what is found in the atmosphere’s air, it swept across the city on the ground. Thousands of people and living things died almost immediately, being suffocated by the toxic cloud and many died in accidents while trying to escape from it due to the desperate and chaotic evacuation of the city.

An estimated 10,000 people died in the first week after the toxic leak and at least 25,000 later died as a direct result of the disaster, which affected more than 600,000 people, 150,000 of whom suffered serious sequelas. In addition, thousands of livestock and pets also perished and the whole environment around the location of the accident was seriously polluted by toxic substances and heavy metals that will take many years to disappear. The chemical plant was abandoned after the accident, and the victims have not been compensated, something that the Indian Government wants to reverse, as recently indicated.

The lessons we learn from this unfortunate accident have had a significant impact on process safety and how we should be educated and trained to prevent future accidents:

  • Safety culture: No safety measures that can prevent an accident if there is not a safety culture that governs the behaviour of management and employees. In Bhopal this basic pillar was not present or was weak.
  • Safety management: In 1984 safety management systems were not widely established, although there were recommendations and procedures such as PSM (Process Safety Management) from DuPont or the Center for Chemical Process Safety (CCPS) from the American Institute of Chemical Engineers. There were two major accidents in 1984 (Bhopal and the explosions of PEMEX in Mexico), which created the need for an organized and systematic approach.
  • Intrinsically safe design: The application of the principles of intrinsically safe design are those that offer the best results. In Bhopal the main cause of the disaster was unnecessary storage of large quantities of MIC, which ultimately was what caused the mass poisoning.
  • Knowledge transfer based on learning from accidents. The Bhopal accident still provides valuable lessons after 30 years. Concepts such as “zero accidents” or “total inherent safety” arose as a result of accidents in 1984 as well as what was coined by Professor Trevor Kletz, one of the fathers of modern chemical safety: “Why should we publish accident reports?”.

Since then, there has been significant progress in the development of safety and health at work, which is giving rise to the corporate social responsibility initiatives that are operating in recent times, such as Responsible Care, a voluntary global initiative for the chemical industry under which companies work to continuously improve their performance in safety, health and the environment. Paradoxically, however, one of the companies that created the Responsible Care initiative in 1987 was Dow Chemical, the company that acquired at the time the assets of Union Carbide, and has yet to take any responsibility for the accident, despite it was found that the three factors that triggered the tragedy of December 3, 1984: Lack of technical expertise, corrosion of materials and equipment, and deactivation of safety measures, could have been controlled by the company.


Disasters like Bhopal or the Chernobyl nuclear accident in 1986, were incidents that tragically started to concoct the current concept of the safety culture. Surely, the lives that those accidents took helped create a new safety culture that has saved the lives of many other people from disaster. Or at least that’s one of the only positive lessons we have managed to find…


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