Bhopal AccidentBhopal AccidentA Case StudyA Case Study

A. A. QureshiA. A. Qureshi

References:

1. Source: Fleddermann, C. B., Engineering Ethics, 2nd Edition, 2004, Pearson Education, India.

IntroductionIntroduction 2, December, 19842, December, 1984 Leak developed in a storage tank at Leak developed in a storage tank at

a Union Carbide Chemical Plant in a Union Carbide Chemical Plant in Bhopal IndiaBhopal India

Tank ContainedTank Contained 10,000 gallons of Methyl Isocyanate 10,000 gallons of Methyl Isocyanate

(MIC)(MIC) A highly toxic chemical used in the A highly toxic chemical used in the

manufacture of pesticidesmanufacture of pesticides The leask sent a toxic cloud of gas The leask sent a toxic cloud of gas

over surrounding of Bhopalover surrounding of Bhopal Death of over 2000 peopleDeath of over 2000 people Injuries over 200,000Injuries over 200,000

Leak was attributed to accidental Leak was attributed to accidental puring of water into the tank.puring of water into the tank.

Water reachts very vigorously with Water reachts very vigorously with MICMIC

Causing heating of liquiedCausing heating of liquied

What HappenedWhat Happened In Bhopal the mixing of water with MIC In Bhopal the mixing of water with MIC

increased the temperature of the liquid in increased the temperature of the liquid in the tank to an estimated 400 F.the tank to an estimated 400 F.

The high temperature caused the MIC to The high temperature caused the MIC to vaporize leading to a buildup of high vaporize leading to a buildup of high pressure within the tank.pressure within the tank.

When the internal pressure became high When the internal pressure became high enough a pressure relief valve popped open enough a pressure relief valve popped open

Leaking MIC vapors into the air. Leaking MIC vapors into the air.

What might have What might have happenedhappened

The water had probably been The water had probably been introduced in the tank accidentally.introduced in the tank accidentally.

A utility station on the site contained A utility station on the site contained two pipes side by side. two pipes side by side.

One pipe carried nitrogen which was One pipe carried nitrogen which was used to pressurized the tank to allow used to pressurized the tank to allow the liquid MIC to be removed.the liquid MIC to be removed.

The other pipe contained water. The other pipe contained water.

… … It appears that instead of connecting It appears that instead of connecting

the nitrogen pipe, someone the nitrogen pipe, someone accidentally connected the water accidentally connected the water pipe to the MIC tank. pipe to the MIC tank.

The accident was precipitated when The accident was precipitated when an estimated 240 gallons of water an estimated 240 gallons of water were injected into the MIC storage were injected into the MIC storage tank.tank.

In most of the cases any one factor In most of the cases any one factor alone probably wouldn’t have led to alone probably wouldn’t have led to the accident but the combination of the accident but the combination of theses factors made the accident theses factors made the accident almost inevitable and the almost inevitable and the consequences worse. consequences worse.

A major factor in this accident was A major factor in this accident was the curtailment of plant maintenance the curtailment of plant maintenance as part of a cost cutting effort.as part of a cost cutting effort.

The MIC storage tank had a The MIC storage tank had a refrigeration unit on it, which should refrigeration unit on it, which should have helped to keep the tank have helped to keep the tank temperatures closer to normal, even temperatures closer to normal, even with the water added, and might have with the water added, and might have presented the vaporization of the liquid.presented the vaporization of the liquid.

However, this refrigeration unit had However, this refrigeration unit had stopped working five months before the stopped working five months before the accident and hadn't yet been repaired.accident and hadn't yet been repaired.

The tank was also equipped with an alarm The tank was also equipped with an alarm that should have alerted plant workers to the that should have alerted plant workers to the dangerous temperatures; this alarm was dangerous temperatures; this alarm was improperly set, so no warning was given. improperly set, so no warning was given.

The plant was equipped with a flare tower. The plant was equipped with a flare tower. This is a device designed to burn vapors This is a device designed to burn vapors before they enter the atmosphere and ti before they enter the atmosphere and ti would have been able to at least reduce if would have been able to at least reduce if not eliminate the amount of MIC reaching not eliminate the amount of MIC reaching the surrounding neighbourhood.the surrounding neighbourhood.

The flare tower was not functioning at the The flare tower was not functioning at the time of accident. time of accident.

Finally a scrubber that was used to Finally a scrubber that was used to neutralize toxic vapors was not activated neutralize toxic vapors was not activated until the vapor release was already in until the vapor release was already in progress. progress.

Some investigators pointed out that the Some investigators pointed out that the scrubber and flare systems were probably scrubber and flare systems were probably inadequate, even had they been inadequate, even had they been functioning. functioning.

However, had any of these systems been However, had any of these systems been functioning at the time f the accident the functioning at the time f the accident the disaster could have at least been disaster could have at least been mitigated if not completely averted.mitigated if not completely averted.

The fact that none of them were operating The fact that none of them were operating at the time ensured that once the water at the time ensured that once the water had been mistakenly added to the MIC had been mistakenly added to the MIC tank, the ensuing reaction would proceed tank, the ensuing reaction would proceed undetected until it was too late to prevent undetected until it was too late to prevent the accident.the accident.

BlameBlame It is unclear to whm the ultimate blame It is unclear to whm the ultimate blame

for the acciedent should be alidfor the acciedent should be alid The plant designers clearly did their job The plant designers clearly did their job

by anticipating problems that wuold by anticipating problems that wuold occur and installing safety systems to occur and installing safety systems to prevent or mitagete potential accidents.prevent or mitagete potential accidents.

The management of the plant seems The management of the plant seems obviously negligent.obviously negligent.

It is sometimes necessary for some safety It is sometimes necessary for some safety features to be taken off-line for repair or features to be taken off-line for repair or maintenance.maintenance.

But to have all of the safety systems But to have all of the safety systems inoperative simultaneously is inexcusable.inoperative simultaneously is inexcusable.

Union Carbide also seems negligent in not Union Carbide also seems negligent in not preparing a plan for notifying and preparing a plan for notifying and evacuating the surrounding population in evacuating the surrounding population in the event of an accident.the event of an accident.

Leaky valves in the MIC system had Leaky valves in the MIC system had been a problem at the Bhopal plant been a problem at the Bhopal plant on at least six occasions before the on at least six occasions before the accident. accident.

One of these gas leaks invovlved a One of these gas leaks invovlved a fatality. fatality.

AftermathAftermath Lawsuits totaling over $250 billion were Lawsuits totaling over $250 billion were

filed on behalf of the victims of the filed on behalf of the victims of the accident.accident.

Union Carbide helped set up job training Union Carbide helped set up job training and relocation programs for victims of the and relocation programs for victims of the accident.accident.

Chairman of Union Carbide, Warren Chairman of Union Carbide, Warren Anderson, was charged in the Indian Anderson, was charged in the Indian courts with culpable homicide, a criminal courts with culpable homicide, a criminal (rather than a civil) charge.(rather than a civil) charge.

Ultimately it has been estimated that Ultimately it has been estimated that approximately 10000 injured in the approximately 10000 injured in the accident will suffer some form of accident will suffer some form of permanent damage [Atlantic permanent damage [Atlantic Monthly, March 1987, p.30]Monthly, March 1987, p.30]