This month marks the 35th anniversary of the terrible tragedy at Bhopal. In this 35th edition of CHEMINGINEERING, our columnist revisits Bhopal and examines the many failures and causes. Bhopal also taught us many lessons and the chemical industry is a distinctly safer place than what it was 35 years ago.
35 years ago this month, a horrific incident happened at Bhopal. It killed thousands and injured hundreds of thousands. Bhopal became synonymous with industrial catastrophes. The art and science of safety advances only through accidents and near-miss incidents; thus Bhopal became an unfortunate milestone in the history of chemical industry. Bhopal was a rude wake-up call to the chemical industry. Many checks and balances were put in place, some legislatively, others voluntarily. In the aftermath of a terrible human tragedy, the chemical industry learned to be more responsible.
The Incident
It is worth recalling what happened in the pesticide plant of Union Carbide India at Bhopal on the night of 2nd/3rd December 1984. Water leaked into a storage tank of Methyl Isocyanate (MIC) and triggered a runaway chemical reaction. As the temperature and pressure inside the tank increased, a safety valve in the tank opened and released a massive cloud of the toxic gas into the atmosphere. The killer gas spread far and wide leaving behind a terrible tragedy in its wake.
Failures
Water had leaked into the tank through a faulty valve intended for cleaning. The refrigeration system designed to keep the contents of the storage tank cool was dysfunctional, the refrigerant having been drained for use elsewhere in the plant. The gauges in the storage tank were not functioning and failed to signal the increase in temperature and pressure. The vent gas scrubber intended to neutralise MIC with caustic soda solution was not operational and allowed untreated MIC to be discharged into the atmosphere. The flare for burning MIC was also not operational. The water curtain with the stated purpose of quelling the gas cloud could not develop the desired height due to inadequate pressure. The community alarm for release of toxic gas was not activated early enough.
Root Cause
The plant was initially set up for formulating pesticides by importing MIC in small quantities from the parent company. Subsequently to improve the competitiveness, the company implemented backward integration and started to manufacture the raw materials in the same plant. But as demand for pesticides dropped, following crop failures in early 1980s, the company decided to suspend production and started to dismantle equipment for shipping to other locations. Since the facility was bleeding money for the company, there were severe cutbacks in plant personnel. Maintenance was poor and the safety awareness was appallingly poor. MIC inventory thus stood with safety systems seriously compromised in a plant that has ceased manufacturing operations. At the root of the tragedy was a poor understanding of the reactive hazards associated with MIC.
Fallouts
There were several learnings from Bhopal which got translated into many beneficial outcomes across the world. The general awareness of safety went up by several notches, both in the industry and among the lay citizens. Chemical industry began reviewing and reducing their inventory of hazardous materials. Many multinational companies took concerted action to bring up the safety standards of their plants located in less developed countries to the same footing as those in their home countries. Communities living next to hazardous chemical plants began to take active interest in safety and disaster management. Many governments enacted tougher legislations and also started to enforce them strictly. Investigations of incidents became more diligent. Courses on safety were started by many institutions and universities. Safety training was accorded priority and treated with respect. Safety became an important cornerstone in process development and design. Principles of Inherent Safety and Process Intensification gained currency in process design.
Reactive Hazards
When Bhopal happened, the knowledge about reactive hazards and runaway reactions was next to nothing. It took another 14 years before the US Chemical Safety and Hazard Investigation Board (CSB) uncovered as many as 167 “incidents” involving uncontrolled chemical reactions. CSB’s investigation also revealed that more than half of these “incidents” involved chemicals not covered by OSHA or US EPA. OSHA, EPA, American Chemical Council (ACC) and Synthetic Organic Chemical Manufacturers Association (SOCMA) joined hands to educate the industry about chemical reactivity hazards. The Center for Chemical Process Safety (CCPS), the process safety arm of AIChE set up in 1985, has developed and published comprehensive set of guidelines on effectively managing reactive hazards.
Management of Change
Post Bhopal, Management of Change (MoC) became a best practice to ensure that safety, health and risk are not compromised when an organisation makes changes to its facilities, operations or personnel. This was singularly absent in Bhopal and was the primary cause of the disaster. The plant had many safety features, but they were all either crippled or disabled because the management was in the process of stopping operations and shipping out the plant. The most important lesson from Bhopal is that even simple changes, if not properly managed, can lead to catastrophic consequences. In the aftermath of Bhopal, CSB investigations identified lack of MoC as the underlying cause in several incidents. An effective MoC should address all changes that could affect the safety of plant and personnel, regardless of whether the change is permanent or temporary.
Responsible Care
Notwithstanding the terrible tragedy at ground zero, the fallouts of the Bhopal gas leak were very positive in faraway North America and Europe. The most significant among them was the development and evolution of the principles of Responsible Care by the Canadian Chemical Producers Association in 1985. In 1988 the American Chemistry Council adopted this programme, followed by many other countries through their national chemical associations. Signatory companies to Responsible Care must fulfill specific environmental, health, safety and security performance criteria. Today, Responsible Care is practiced by chemical companies in more than 65 countries around the world. Nearly 150 companies in India are signatories to the Responsible Care programme.
EPA
Following Bhopal, the environmental awareness and activism increased significantly in our country. The Environmental Protection Act was passed in 1986 and it is the country’s first piece of legislation that gave government the authority to prohibit, close or regulate any industry. Over the years, EPA has been used to frame a set rules and regulations for controlling pollution and management of hazardous waste.
Epilogue
The terrible tragedy at Bhopal has taught us many invaluable lessons. Many best practices have been implemented by the chemical industry and there is no gainsaying the fact that there has been a significant reduction in the frequency and severity of accidents, in comparison to the increased production volumes after 1984. Our understanding of reactive hazards and runaway reactions has improved considerably. The Responsible Care movement has taken roots in the industry and is growing. The price humanity paid in Bhopal may not have been in vain.
Readers’ responses may be sent to: k.sahasranaman@gmail.com or chemindigest@gmail.com
