Bhopal is known for its historical records, artificial lakes and greenery but most of all, the city is remembered across the globe for the worst industrial mishap of the world.

Post-midnight on December 3, 1984, poisonous gas that leaked from the factory of Union Carbide in Madhya Pradesh capital Bhopal killed thousands of people directly. The incident is now known as the Bhopal disaster or Bhopal gas tragedy.

As per official records, the Bhopal gas tragedy killed 3,787 people. The figures were updated by the Madhya Pradesh government later as the immediate official estimate had put the death toll due to gas leak from Union Carbide factory at 2,259.

However, activists fighting for justice for Bhopal gas tragedy victims put the figures of death between 8,000 and 10,000. In an affidavit, submitted in 2006, the government said that the Bhopal gas leak caused 5,58,125 injuries that included approximately 3,900 severely and permanently disabling injuries.

HOW DID IT HAPPEN?

The gas leak in the Union Carbide (now known as Dow Chemicals) was reported after midnight on the intervening night of December 2 and 3. The incident had taken place at the Plant Number C of the Union Carbide factory in Bhopal.

As the cool morning breeze picked up pace, it carried the poisonous gas leaking from the Union Carbide factory to rest of the city and killing people - both awake and asleep. As per government's affidavit, about 3,000 people died of poisonous gas within a few hours of the incident.

It is estimated that about 40 tonnes of methyl isocyanate (MIC) gas and other chemicals leaked from the Union Carbide factory. Methyl isocyanate is extremely toxic and if its concentration in air touches 21ppm (parts per million), it can cause death within minutes of inhaling the gas. In Bhopal, the level was multiple times higher.

WHAT CAUSED MIC LEAKAGE?

The leakage of gas was reported from Plant Number C. As per official record, methyl isocyanate got mixed with water used for cooling the plant. The mixture led to generation of volumes of gases, which put tremendous pressure on Tank Number 610.

The tank cover gave way to building gaseous pressure releasing tonnes of the poisonous gas, which diffused over large area. Approximately 5 lakh people were exposed to the leakage of methyl isocyanate gas.

POST-LEAKAGE SCENE

Bhopal had a population of about 8.5 lakh back in 1984 and more than half of its population was coughing, complaining of itching in eyes, skin and facing breathing problems. The gas caused internal hemorrhage, pneumonia and death. The villages and slums in the neighbouring areas of the factory were the worst affected.

The alarm system of the Union Carbide did not work for hours. No alarm was raised by the factory managers. Suddenly thousands of people started running to hospitals on the morning of December 3 with their complaints.

Unlike today, Bhopal of 1984 did not have too many hospitals. Two government hospitals could not have accommodated half of the population of the city. People were suffering, finding it difficult to breathe and confused. So were doctors, who did not immediately know the reasons for the sudden illness that afflicted every new rushing patient.

Patients complained of dizziness, breathlessness, skin irritation and rashes, some others reported sudden blindness. Doctors of Bhopal had never faced a situation like this. They had no experience in dealing with industrial disaster.

Symptoms of methyl isocyanate exposure were not immediately known to them. And, the two hospitals reportedly treated around 50,000 patients in first two days of the Bhopal gas leak. Officially, the government declared that the gas leakage was contained in eight hours, but the city has is still finding it difficult to come out of its grip even 33 years later.