This month marks the 25th anniversary of the worst industrial accident in history — release of toxic methyl isocyanate (MIC) from a chemical plant at Bhopal, India, that killed thousands. Almost a generation of engineers has entered the field since the 1984 disaster. Hopefully most are aware of the incident even if they don't know its details. They probably can't fathom the horror that those of us who were working then felt or appreciate the profound impact the release has had on how the chemical industry operates.
In case you're unfamiliar with the accident, let me recount the basics. Early on the morning of December 3, 1984, MIC gas leaked from a pesticide plant in Bhopal operated by Union Carbide India. The government of the state of Madhya Pradesh estimates that about 3,800 people died and thousands more suffered disabilities, although other sources put the toll at many times higher.
Separate investigations by Union Carbide and the Indian government blamed the release on a large volume of water getting into a tank containing about 42 metric tons of MIC, which was used an as intermediate in the production of carbaryl. This caused a chemical reaction that forced a release valve to open.
A number of factors made the accident so disastrous, including: the amount of MIC on site and the way in which it was stored, shortcomings in safety system operation, and the large number of people living in a shanty town that had grown up adjacent to the plant.
The incident led to important efforts to make the industry safer. For instance, in 1985 the American Institute of Chemical Engineers, New York City, established the Center for Chemical Process Safety, which ever since has played a leading role in providing publications and conferences to address safety issues. Governments also responded, instituting or bolstering safety mandates. In the U.S., as the Web site of the Environmental Protection Agency (EPA) Web notes:
"When Congress passed the Clean Air Act Amendments of 1990, it required EPA to publish regulations and guidance for chemical accident prevention at facilities using extremely hazardous substances. The Risk Management Plan Rule (RMP Rule) was written to implement Section 112(r) of these amendments. The rule, which built upon existing industry codes and standards, requires companies of all sizes that use certain flammable and toxic substances to develop a Risk Management Program, which includes a(n):
• Hazard assessment that details the potential effects of an accidental release, an accident history of the last five years, and an evaluation of worst-case and alternative accidental releases;
• Prevention program that includes safety precautions and maintenance, monitoring, and employee training measures; and
• Emergency response program that spells out emergency health care, employee training measures and procedures for informing the public and response agencies (e.g., the fire department) should an accident occur."
Chemical companies today routinely employ formal methods such as hazard and operability studies (hazops) to identify potential risks and ways to deal with them. Many sites now treat management of change more rigorously. Safety concerns also are prompting increasing interest in the concept of inherent safety — designing out hazards instead of just building in countermeasures against them (see "Rethink Your Approach to Process Safety.")
But even after all these years and all the attention, more needs doing.
We asked internationally recognized safety guru Trevor Kletz to reflect on lessons learned from Bhopal and, particularly, to indicate where companies still must improve. (Kletz long has focused on safety. In 1968 he became the first technical safety advisor for Imperial Chemical Industries, then one of the world's largest chemical companies but now defunct (see "ICI Fades Into History"). It pioneered use of hazops, and Kletz authored the first book on the topic. He has written extensively about safety. The latest edition of his landmark book "What Went Wrong: Case Histories of Process Plant Disasters and How They Could Have Been Avoided" has just come out (see "Make the Most of Your Summer Reading.")
Unfortunately, as Kletz points out, chemical companies still blunder into serious accidents because they don’t remember previous incidents or attempt to find out about other firms’ past miscues that had serious consequences.
So, industry, while deserving congratulations for its solid progress since Bhopal, still has work to do. It must put more effort into effectively retaining, retrieving and sharing accident information. That’s one lesson from Bhopal that chemical makers haven’t fully grasped.
Mark Rosenzweig is Editor in Chief of Chemical Processing. You can e-mail him at MRosenzweig@putman.net.