On 3 December 1984, one of history's largest industrial disasters took place at a pesticide plant owned by Union Carbide in Bhopal, India. In the early morning of that day, a large (90 000 lb) storage tank containing toxic methyl isocyanate (MIC) spread its contents over hundreds of shanties and huts that surrounded the factory. Four months after the disaster, the Indian Government reported that 1430 people had died during the disaster. In 1991, the Indian government updated this count to more than 3800 deaths, and approximately 11 000 people with disabilities. Although this was unknown at the time of the accident, the disaster was caused by a disgruntled plant worker, who tried to spoil a batch of MIC by adding water to a storage tank.

The plant in Bhopal was operated by Union Carbide India Limited (UCIL), at the time owned by Union Carbide, U.S.A. for slightly more than 50%. UCIL was doing well in its 50 year existence; 14 national production plants, and $200 million in annual sales. The plant in Bhopal had a humane goal; the production of pesticides for the local market, to enhance the Indian agricultural sector. The large scale production of pesticides could help stop famine in the poorest regions of India.

The two major products of the Bhopal plant were Sevin, and Temik; two biodegradable pesticides that were produced as alternatives for DDT. These pesticides, chemically belonging to the group of carbamates, are produced by the reaction of an alcohol or phenol with an isocyanate (compound containing a -N=C=O group). Hence, large quantities of methyl isocyanate were present. The following accident scenario took place in the night from December 2- 3, 1984:

10:20    Tank 610, containing 90 000 lb of MIC is at the
         normal operation pressure of 2 psig

11:00    Shift change. The control room operator noticed that the
         pressure in tank 610 was 10 psig. This pressure was not
         unusual, since it normally varied from 2-25 psig. However, the
         sharp pressure increase was unusual. It is unknown whether the
         operator was aware of the earlier 2 psig reading. At the same
         time, a MIC leak was reported in the process area, but its
         source was not found, and no investigation ensued.

00:15    Another MIC leak was reported. Pressure in tank 610 was
         recorded as 30 psig, and rapidly rose to 55 psig (maximum of
         instrument scale). The operator notified his supervisor, and
         ran outside to check the tank. The tank was radiating heat, and
         making rumbling and screeching noises from the safety valve.
         Inside the control room, the sound of cracking concrete was
         heard. At this time the scrubber was turned on.

00:20    The plant's supervisor was notified of the gas leak

00:45    The supervisor's log records show that the derivatives' unit
         operations were suspended at this time.

14:30    Pressure in the tank subsides, and its safety valve closes.

In the aftermath, it became clear that the disaster was caused by a reaction of MIC with water. Methyl isocyanate is a volatile compound that is toxic and irritating to the nose and throat. Although MIC is a liquid at room temperature, it has a very low boiling point (43-45 C). MIC reacts with water to form methylamine and carbon dioxide:

      CH3NCO + H2O -> CH3NH2 + CO2

The reaction is exothermic, and both products are gasses. The gas production caused a rapid increase in pressure inside the tank. The exothermic reaction increased the temperature, causing a further increase in pressure. The increased temperature also increased the volatility of MIC. Finally, the tank ruptured, exposing more than 200 000 people to the toxic chemical.

Initially, it was hypothesized that water had entered the tank by careless flushing of supply lines in another part of the plant. Further evidence presented in 1986 showed that the accident was caused by sabotage actions of a disgruntled plant worker. This worker added water to a storage tank to deliberately spoil a batch of pesticide.

In the legal aftermath, UCIL settled for $470 million dollars with the government of India, acting on behalf of the victims of the tragedy.

Unproven Technology

The Bhopal, India plant was established in 1969 by Union Carbide and expanded to produce carbaryl (Methyl isocyanate or "MIC" is a intermediary) by 1979, they hoped that the large agricultural presence in the region would be a potential gold mine as farmers would purchase pesticide in large quantities. The forecast proved to be wrong; Indian farmers struggling with droughts and floods simply could not afford the chemicals, and by the end of the early 1980s, the plant had ceased active manufacture.

With the end of active manufacturing, the plant was effectively left to rot with sub-standard maintenance, myriad unsafe cost cutting measures and the fact that Union Carbide had been secretly installing untested technology since its establishement in the plant all combined to play in the failure of the plant.

There were 6 safety systems at the plant at the time of the failure, but all were either turned off as part of cost cutting measures or under repair when they were needed the most:

  • Flare Tower: Designed to burn off gas; the connecting pipe had been disconnected for maintenance.
  • Vent Gas Scrubber: Could have detoxified the leaking gas, but it had been turn off. In addition it was out of lye and undersized.
  • Water Curtain: Prevents toxic gas release, it was undersized.
  • Pressure Valve: Defective.
  • Mandatory Refrigeration Unit for MIC: Turned off to cut costs.
  • Run Off Tank: Already contained MIC.

"A Disgruntled Employee"

The unsafe conditions and deplorable maintenance at the Union Carbide plant would come to a head at 12:02 AM on December 3, 1984 when a worker did a routine pipe flushing; multiple stopcocks failed in the corroded pipe and water flowed freely into tank E610 which held 40 tons of MIC. This led to the catastrophic events as the exothermic reaction blew the tank out of its concrete sarcophagus and poisoned the city.

According to Union Carbide however, the resulting disaster was not the result of corporate negligence, but of a disgruntled employee who attempted to ruin a batch of pesticide. The problem is Union Carbide has never attempted to charge, much less reveal the name of this employee.

Union Carbide's and its current owner Dow Chemical Company's (Purchased in 2001) refusal to appear in India to face charges is only further proof of their negligence, in fact, Union Carbide publicly admitted their refusal to submit to the summons years ago. Warren Anderson, Union Carbide's CEO at the time of the disaster, is also named as defendant, was detained and released on bail when he visited India immediately following the disaster, but he has never returned to face the charges against him as well. Extradition attempts are only half-hearted and have never succeeded.

Twenty Years of Contamination

Amidst the ruins of the Bhopal plant, children play and women gather firewood. The vine strewn ruins of the Union Carbide facility remain as deadly as ever. Located near the heart of the city, only half-hearted attempts at cleanup of the site have been attempted. Pools of mercury contaminated water, open waste containers, and batches of MIC remain strewing around the compound seeping into the groundwater and poisoning a new generation of victims.

Log in or register to write something here or to contact authors.