THE GAS DISASTER :• For reasons that remain unclear, the Cooling System of Tank610
was not functioning in the last months of 1984.
• Late in the evening of December 2nd , it was hypothesized that Water (either through mechanical malfunction or operational
error) entered the tank mixing with the already stored 42 tons of MIC.
• The resulting exothermic reaction increased the temperature inside the tank to over 200°C (392 °F) and raised the pressure
• About 30 metric tons of Methyl Isocyanate (MIC) escaped from the tank into the atmosphere of Bhopal in 45 to 60 minutes.
• In November 1984, most of the Safety Systems were not functioning and many valves and lines were in poor condition.
• In addition to this, several vent Gas Scrubbers had been out of service as well as the steam boiler, intended to clean the pipes
was not operational.
• Another issue was that, Tank 610 contained 42 tons of MIC which was much more than what safety rules allowed.
• A runaway reaction started, as soon as the accident happened which was accelerated by contaminants, high temperatures and
• The reaction accelerated up by the presence of iron from corroding non-stainless steel pipeline which resulted in the
The gases were blown in South-Eastern direction over Bhopal.
As of 2008, UCC had not released information about the possible composition of the cloud.
Apart from MIC, the gas cloud may have contained Phosgene, Hydrogen Cyanide, Carbon Monoxide, Hydrogen Chloride, Oxides of Nitrogen, Monomethyl Amine (MMA) and Carbon Dioxide, either produced in the storage tank or in the Atmosphere.
The gas cloud was composed mainly of materials denser than the surrounding air, stayed close to the ground and spread outwards
through the surrounding community.
The nature of the cloud is still discussed. The chemical reactions would have produced a liquid or solid aerosol with high density. The concentrations at ground level would have been much higher than
1. The timing of the explosion was such that most of those exposed (an estimated 3,50,000 were asleep) .
2. Survivors report being awakened by an acrid (chili-like) stinging of the eyes and throat.
3. The low boiling point of MIC caused it to be re-vaporized at body temperature and inhaled deeply into the lungs: as a result damage to the bronchial was extensive and the post-mortem findings in those who died immediately after the leak reported widespread
airway Necrosis with Pulmonary Enema and Haemorrhage.
4. Owing to their height, children and other people of shorter stature inhaled higher concentrations. Many people were trampled trying
5. Thousands of people had succumbed by the morning hours.
o There were mass funerals and mass cremations. Bodies were
dumped into the Narmada River, less than 100 km from Bhopal.
o 170,000 people were treated at hospitals and temporary
o 2,000 buffalo, goats,
&other animals were collected and buried.
o Within a few days, leaves on trees yellowed and fell off.
o Supplies, including food, became scarce owing to suppliers'
o Fishing was prohibited causing further supply shortages.
Within a few days, trees in the vicinity became barren, and 2,000 bloated animal carcasses had to be disposed of.
On 16 December, tanks 611 and 619 were emptied of the remaining MIC. This led to a second mass evacuation from Bhopal.
The Government of India passed the "Bhopal Gas Leak Disaster Act" that gave the government rights to represent all victims, whether or not in India.
Complaints of lack of information or misinformation were widespread.
An Indian Government spokesman said, "Carbide is more interested in getting information from us than in helping our relief work.“
Formal statements were issued that air, water, vegetation and foodstuffs were safe within the city.
At the same time, people were informed that poultry was unaffected, but were warned not to consume fish. No one under the age of 18 was registered at the time of the accident. The number of children exposed to the gases was
at least 200,000.
• The official immediate death toll was 2,259 and the
government of Madhya Pradesh has confirmed a total of 3,787
deaths related to the gas release.• Others estimate 8,000 died
within two weeks and another 8,000 or more have since died
from gas-related diseases.• A government affidavit in 2006 stated the leak caused 5,58,125
injuries including 38,478 temporary partial and
approximately 3,900 severely and permanently disabling
injuries.• 2,000 bloated animal carcasses
had to be disposed.
SHORT-TERM HEALTH EFFECTS :
– Apart from MIC, the
dense gas cloud may
• hydrogen cyanide,
• carbon monoxide,
• hydrogen chloride,
• oxides of nitrogen,
• monomethyl amine
• carbon dioxide, either produced in the storage tank or in theatmosphere.
– The initial effects of exposure were coughing, vomiting, severeeye irritation and a feeling of suffocation.
• It is estimated 100,000 to 200,000 people have permanentinjuries.
• Reported symptoms are :
– eye problems,
– respiratory difficulties,
– immune and neurological disorders,
– cardiac failure secondary to lung injury,
– female reproductive difficulties and
– birth defects among children born to affected women.
• The Indian Government and UCC deny permanent injuries werecaused by MIC or the other gases.
FACTORS LEADING TO THE GAS LEAK
• Plant Management Deficiencies were also identified –
– lack of skilled operators,
– reduction of safety management,
– insufficient maintenance,
– inadequate emergency action plans.
• Use of a more dangerous pesticide manufacturing method, or “ROUTE”, where same raw materials are combined in a different manufacturing order, with phosgene first reacted with naphthol to form a chloroformate ester, which is then reacted with methyl amine.
• In the early 1980s, the demand for pesticides had fallen, but production continued, leading to buildup of stores of unused MIC.20