Bhopal Disaster

Toxicological Perspective

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The methyl isocyanate poisoning of Bhopal, India had many disastrous consequences. Hundreds of thousands of people were injured and around 15,000 died. The toxicological and environmental problems are ongoing. Due to a lack of political willpower, the toxic waste from the disaster has still not been cleaned up. Higher rates of Cancer and diseases affecting the central nervous system, liver, and kidneys were witnessed. Also, water analysis is poor due to continued contamination from benzene hexachloride and Mercury that persists to this day.

Background

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The Union Carbide plant was established in Bhopal in 1969 and it began to produce the insecticide Carbaryl. methyl isocanyte is an ingredient of carbaryl, and on the morning of December 3, 1984, a holding tank containing 43 tons of methyl isocyanate overheated and released the toxic gas. Because methyl isocyanate is heavier than air, it traveled over the ground through the Bhopal city center. The transportation system collapsed, and many people were trampled to death in a mad rush to flee the visible gases. In total, 15,000 people died and 150,000-600,000 people were injured.
The contamination and deaths were a result of numerous factors:

• Recent documents obtained through discovery in the course of a lawsuit against Union Carbide for environmental contamination (before a New York Federal District Court) revealed that Carbide had exported "untested, unproven technology" to the Indian plant. Unlike Union Carbide plants in the USA, its Indian subsidiary plants were not prepared for problems. No action plans had been established to cope with incidents of this magnitude. This included not informing local authorities of the dangers of chemicals used and manufactured at Bhopal.

• Reports issued months before the incident by scientists within the Union Carbide corporation warned of the possibility of an accident almost identical to that which occurred in Bhopal. The reports were ignored outright and never made it to senior staff. Due to falling sales, staff had been laid off and safety checks became less and less frequent.

• Slip-blind plates that would have prevented water from pipes being cleaned from leaking into the MIC tanks via faulty valves were not installed. Their installation had been omitted from the cleaning checklist.

• At the time of the event, the MIC tank refrigeration unit was disabled to save money, and some of its coolant was being used elsewhere. A simple press of a button in the control room would have activated it to at least use the remaining coolant, but this was overlooked by staff.

• The gas scrubber was placed on standby, and therefore did not attempt to clean escaping gases with sodium hydroxide (caustic soda), which may have brought the concentration down to a safe level.

• The water curtain that may have reduced the concentration of the gas was only set to ~13 m and did not reach the gas; it was not designed to contain a leak of such magnitude. Though the audible external alarm was activated to warn the residents of Bhopal, it was quickly silenced to avoid causing panic among the residents. Thus, many continued to sleep, unaware of the unfolding drama, and those that had woken assumed any problem had been sorted out.

• The flare tower used to burn off gases before they are allowed to escape into the air was inoperational pending repairs.

• Doctors and hospitals were not informed of proper treatment methods for MIC gas inhalation. They were told to simply give cough medicine and eyedrops to their patients.

Union Carbide agreed to pay $470 million to the residents of Bhopal. That amount is lower than in the lawsuit and substantially lower than similar Asbestos cases Union Carbide was settling concurrently in the United States. By the end of October 2003, according to the Bhopal Gas Tragedy Relief and Rehabilitation Department, compensation had been awarded to 554,895 people for injuries received and 15,310 survivors of those killed. The average amount to families of the dead was $2,200. Union Carbide also attempted to distance itself from the tragedy by blaming its subsidiary in India and even fabricated stories about a Sikh extremist group and disgruntled former employees bent on sabotaging the plant.

Health Effects Summary for MIC

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Immediate Health Effects  (0-6 months)

• Ocular: Chemosis, redness, watering, ulcers, photophobia
• Respiratory: Distress, pulmonary edema, pneumonitis, pneumothorax
• Gastrointestinal: Persistent diarrhea, anorexia, persistent abdominal pain
• Genetic: Increased chromosomal abnormalities
• Psychological: Neuroses, anxiety states, adjustment reactions
• Neurobehavioral: Impaired audio and visual memory, impaired vigilance attention and response time, Impaired reasoning and spatial ability, impaired psychomotor coordination

Long-term Health Effects

• Ocular: Persistent watering, corneal opacities, chronic conjunctivitis
• Respiratory: Obstructive and restrictive airway disease, decreased lung function
• Reproductive: Increased pregnancy loss, increased infant mortality, decreased placental/fetal weight
• Genetic: Increased chromosomal abnormalities
• Neurobehavioral: Impaired associate learning, motor speed, and precision