"As a former Union Carbide Corp. (UCC) employee, the moment I heard the news is etched in memory, mirroring the experiences of my colleagues. Delving into the root cause of this tragic incident not only offers insights but also presents opportunities to glean valuable lessons from the mistakes that precipitated the Bhopal disaster."
In the 11th century, Raja Bhoj of Dhar founded a city on the shores of a beautiful lake in central India. Today, that city, Bhopal, is a bustling metropolis of 2 million people. The city and surrounding area is home to a large wildlife refuge, a museum of Indian tribal life, a collection of historical palaces and temples, and Stone Age cave paintings.
Almost anywhere else in the world, this city would be a major tourist attraction, but Bhopal is well-known for something else: It is the site of the deadliest industrial accident in history.
"The Tragedy Unfolds: In the early hours of December 3, 1984, a devastating release of toxic methyl isocyanate (MIC) gas occurred at a Union Carbide India Limited (UCIL) pesticide plant. The lethal cloud engulfed a densely populated area south of the plant, extending over a railway station 2 km away, resulting in numerous casualties among those waiting for and arriving on trains.
Approximately 500,000 people downwind faced exposure to the lethal gas cloud. While the exact death toll remains uncertain, estimates range from a commonly accepted 2,000 (D’Silva 2006) to a potentially higher figure of 8,000 (Amnesty International 2004). In the immediate aftermath, thousands perished, with tens of thousands sustaining severe injuries. Tragically, many succumbed prematurely in the months and years following the release, underscoring the profound and enduring impact of the Bhopal disaster."
A Personal Connection
"As a former employee of Union Carbide Corp. (UCC), the U.S. parent company of UCIL during the tragic incident, the news of the Bhopal disaster is etched in my memory, much like my fellow UCC colleagues.
During a recent trip to India, I visited Bhopal to witness the site of the idle plant, now abandoned for 30 years, succumbing to rust and overgrowth. The debate over its fate continues, with some advocating for demolition and cleanup, while others propose its preservation as a UNESCO World Heritage site.
The aftermath persists in the local community, evident through billboards, graffiti demanding restitution, and ongoing medical facilities treating individuals for various health issues, as documented by Amnesty International. The social and economic repercussions are profound, exacerbating poverty, causing loss of breadwinners, and imposing lasting stigmas on those affected, particularly young women.
Reflecting on the approaching 30th anniversary, it becomes evident how little awareness exists about this catastrophic event. It is crucial to commemorate the lives lost and those still suffering while recommitting to learning from this tragedy, ensuring that such a devastating incident never recurs."
Seeking the Truth
"The elusive truth surrounding Bhopal remains a challenge to unveil, given the inherent complexities of investigating a catastrophe of such magnitude. The difficulty was compounded by interference from vested interests, adding layers of opacity to the inquiry.
Amidst the myriad accounts and narratives surrounding the incident, much of the information is speculative or driven by the specific agendas of involved parties. Drawing from personal experiences and extensive research, I've distilled the following analysis.
Examining the Political, Legal, Economic, and Social Landscape, safety expert Trevor Kletz's perspective on the absence of a singular root cause is pertinent. Instead, he suggests a point at which questioning ceases. In this context, delving into the days of the British Raj becomes essential, as the residue of colonialism appears to have left an indelible mark on the psyche of the people and the political and legal systems of India, contributing in multifaceted ways to the tragic events in Bhopal."
"Fig. 1 provides a snapshot of the cultural environment during the Bhopal accident, highlighting key drivers on the left and their consequential effects on the right.
Drivers of the Culture (Left side):
1. The recent history of colonialism, signifying India's past subjugation by a foreign power.
2. The pervasive poverty in the country, exacerbated by abject conditions near the plant.
3. The prevailing appeal of socialism in India during that historical period.
4. The absence of a safety culture within the industrial framework.
Effects of the Drivers (Right side):
1. Establishment of a legal system overtly pro-India, pro-citizen, and anti-foreign corporation, dissuading Western companies like IBM and Coca-Cola from sustaining operations in the country.
2. Rapid development of a shantytown in the supposed buffer area around the plant, supported by local politicians who resisted UCIL's efforts to remove squatters.
3. Employee mistrust of management hindered the implementation of a suitable safety culture, impeding the investigation of incidents and near misses as workers concealed them.
This illustration underscores how these cultural factors played pivotal roles in shaping the legal, economic, and social landscape surrounding the Bhopal tragedy."
The plant was not making money for a couple of reasons. Sales were much lower than predicted because of economic hardships in India and unexpected competition. Manufacturing costs were high due to problems with the technology. It cost four times as much to make the pesticide in Bhopal as it did to make it in the United States (Fig. 2).
UCIL had decided to permanently shut down the plant and ship it out of India. The plant was in its last production run at the time of the accident, working off the last batch of MIC.
It was against this legal, political, economic, and social backdrop that the final events and decisions leading to the tragedy unfolded.
Description of the Plant
Fig. 3 illustrates the pesticide production facilities at which the MIC was produced on site in the production plant and consumed on site as a raw material in the pesticide plant (MIC consumer).
Fig. 3—A schematic of the methyl isocyanate (MIC) process plant.
The plant design (partially batch) required MIC storage, which was to be kept at minimum volumes. A caustic scrubber was provided to neutralize the MIC vented from the storage tanks, and a flare was used to burn the vented MIC. A refrigeration system was provided to keep the stored MIC cold to decrease the rate of MIC’s reaction with water and other contaminants.
Initiating Event: Operator Error or Sabotage?
"Accidents often trace back to a triggering event, and in the case of Bhopal, it stemmed from the introduction of a substantial amount of water (approximately 200 gallons) into the MIC tank. While MIC is typically stable, its highly reactive nature with water initiates an exothermic reaction, leading to an increase in temperature and pressure within the tank, eventually triggering venting.
Controversy surrounds the origin of the water in the tank. One account implicates operators in another plant section water-washing the vent header, allegedly allowing water to reach the MIC tank. However, technical scrutiny dismisses this scenario as implausible (Kalelkar 1988), even though it continues to be debated by those with vested legal and political interests.
The more plausible explanation points towards sabotage, with evidence suggesting that a disgruntled worker intentionally injected water into the tank, possibly to spoil the MIC batch (D’Silva 2006; Kalelkar 1988)."
Bypassed or Broken Safeguards
Significant safeguards were designed into the plant to prevent an MIC release, or at least to minimize its impact. Although the safeguards were probably adequate for handling typical initiating events, they may not have been adequate to handle the quantity of water injected into the tank on that day. We will never know, because all of the other safeguards were bypassed, out-of-service that night, or otherwise rendered ineffective.
No Means of Adding Water to the Tank
It is common in industrial facilities to install valves and drains in piping systems to make it easy to vent and drain the systems and inject water, steam, nitrogen, or air for purging or cleaning the systems. The designers of the Bhopal facility were aware that accidental injection of water could be catastrophic. Hence, the installed system had no drains or vents. Investigation (Kalelker) suggested that the injection of water could not have been a simple human error. It appears that the saboteur removed a pressure gauge and installed a hose connection in its place.
Minimizing the Stored Volume of MIC
The simplest of the safeguards was a safety directive to minimize the quantity of stored MIC stored. As indicated in Fig. 3, there were three storage tanks. According to the procedure, two tanks should have been empty and the third should have been at less than 50% level.
The actual level in Tank E-610 was about 70% (and Tank E-611 also contained MIC). Had there been less MIC in the tank, operators may have had the options to add diluent to slow the reaction.
Refrigeration System Out of Service
The rate of an exothermic reaction is decreased by decreasing the temperature. A refrigeration system was provided to keep the MIC at about 30°F. Had the tank been operated at that temperature, the reaction rate would have been much lower and the event may have been far less catastrophic.
Ironically, the refrigeration system was turned off months before the accident as a safety measure. The seals of the pump circulating the MIC through the refrigeration unit were prone to leaks. After one catastrophic seal failure, the refrigeration system was shut down permanently.
Caustic Scrubber
The vented MIC escaped through the vent gas scrubber (caustic scrubber). In the scrubber, it should have contacted caustic (sodium hydroxide), which would have neutralized at least some of the MIC.
There are conflicting reports on the operation of the scrubber. Some report that the scrubber was out of service for maintenance, while others report that it was operating, but that the flowmeter was not working. Hence, we have no direct evidence that caustic was pumped to the scrubber.
Even if the scrubber was in service, it probably had little effect. Scrubbers function by causing intimate contact between the liquid and gas streams. The gas flow rate on the night of the accident was probably from four to five times the scrubber design rate. At that flow rate, the vapor/liquid contact would have been poor.
Flare Out of Service
As in most processing facilities, the ultimate line of defense against vented gases is the flare, which is designed to burn the vented gases going through it. On the night of the accident, the flare was out of service. A section of pipe in the flare header was corroded and the flare had been taken out of service.
Shantytown in the Plant Buffer Area
India is a crowded country with inadequate public transportation. The UCIL plant was a major employer, so it was natural that people would want to live near the plant. The poorest of the poor set up a shantytown along the plant perimeter, many literally using the plant’s concrete fence as one wall of their house. UCIL had tried multiple times to have the shantytown removed, but was unsuccessful because the shantytown residents were voters, and the local politicians supported them.
Ineffective Emergency Response
No on-duty UCIL employees were killed in the event because as the plant operators became aware of what was happening, including the direction from which the wind blew, they chose an appropriate evacuation route.
An effective emergency response would undoubtedly have saved many people in the community. UCIL issued no alarm to the community and provided no information to civil authorities until about 2 hours after the initial release of the gas.
Ineffective Treatment of the Injured
A final safeguard would have been effective treatment of the injured. In the immediate aftermath, the doctors did not know the cause of the incident and were unable to determine the appropriate treatment of the injured.
Local groups argue that still today, thousands are suffering from the exposure and that the funding allotted for their treatment is inadequate.
Internal Communication Failures
It was a remarkable series of defeated safeguards and it seems incredible that a plant would be operated in this manner. As I read the various accident reports, I sensed that the decisions were made by different people at different times. It was possible that no single person knew that all of the safeguards were out of service. It is a fundamental weakness of defense in depth when an individual can bypass a single safeguard, convinced that other available safeguards will provide adequate protection.
The Perfect Storm
"In most major accidents, a recurrent pattern emerges with a cascade of errors, and Bhopal is no exception, presenting a striking list of contributing factors:
1. Financial struggles led to staff and maintenance cutbacks, compromising overall plant safety.
2. A social system that neglected safety culture, fostering tension between management and workers, culminating in intentional sabotage by a disgruntled worker.
3. The impending permanent closure of the plant significantly impacted operator morale, contributing to neglect in maintenance and safety system bypassing.
4. Adverse meteorological conditions played a role, with stable weather and low wind speed allowing the gas cloud to persist over a large section of the city.
5. A glaring lack of an emergency response program or its complete failure.
6. Inadequate treatment of the injured.
Bhopal stands as a tragic "perfect storm" event, and it is unlikely that we will witness another industrial accident of such deadly proportions."
What We Learned
"Bhopal has left an indelible mark on safety culture globally, influencing practices across various industries. Its legacy encompasses now commonplace measures like hazard and operability analysis, management of change, permit to work, and dispersion modeling.
The impact of Bhopal prompted swift actions worldwide, with plants taking immediate measures to restrict the storage and transportation of toxic materials. The likelihood of storing 15,000 gallons of a substance as toxic as MIC has drastically diminished, as the lessons from Bhopal continue to shape and enhance safety standards."
What We Have Not Learned
There were significant problems with the Bhopal plant design. Since then, we have learned to design safer plants. But the plant design played only a small role in the accident, which was caused largely by the failure to operate the plant as the designers intended (e.g., the bypassing of safeguard systems in particular and the violations in adhering to standard operating procedures [SOPs] in general).
UCC recognized the failure to follow SOPs as a root cause and launched a corporatewide program to update SOPs and instill a culture of using them effectively. In the years since, the airline industry has learned to make the following of SOPs a priority, resulting in improvements in the safety of air travel—a lesson that the oil and gas industry has yet to learn.
