The Bhopal Gas Leak is the worst environmental disaster in our history. This disaster occurred on December 12, 1984 at the Union Carbide India Limited (UCIL), a pesticide-manufacturing factory in Bhopal, India, and was caused by a leak of methyl isocyanate gas (MIC) and other lethal gases from the plant (Rosenberg, 2011). The gas cloud emanating from this leak contained nearly 15 metric tons of MIC and spread over the vast and densely populated Bhopal city.
The gas leak killed at least 4,000 people immediately and caused health complications for at least 50,000 inhabitants with some agencies reporting a figure of 500,000. These health complications have resulted in the death of more than 15,000 people over the last two decades while a large number (estimated at 100,000) still suffers from the effects of the gas leak, with ten people dying every year (Broughton, 2005).
Chemicals released during the leakage were deposited in the area around the plant and have continued to seep into the groundwater. Other sources of pollution include leaks from isolation material and residues as the containers used for storing them are slowly wearing out.
Tests carried out by UCIL in 1989 showed that soil and water in the Bhopal neighborhood were poisonous to fish and other aquatic life. In 1994, studies indicated that 21% of the UCIL premises were highly contaminated with toxic chemicals. Apart from humans, animals were also affected by the MIC leak: at least 2,000 animals, both wild and domesticated, were found dead.
Cause of the Disaster
The gas leak is said to have begun when water entered a tank that contained 42 tons of MIC, an ingredient in the production of pesticide. This contact led to an exothermic reaction that elevated temperatures inside the tank to more than 200 0C, leading to a corresponding elevation in pressure. This caused the tank to vent, releasing poisonous gases into the atmosphere, the spread of the leaked gas was hastened by the northwesterly winds blowing over Bhopal (Rosenberg, 2011).
The explanation as to how water entered the MIC tank has varied depending on the investigating agency. Union Carbide, the major shareholder in the firm, stated that such a large amount of water could only enter the tank through sabotage by an employee.
Somebody intentionally put water inside the tank leading to a reaction and eventually a gas leak. However, the Indian government accused Union Carbide of not taking adequate security measures to avert or control a disaster. For example, the company should have installed six safety systems that would either prevent or contain the disaster, none of them worked correctly that night.
Besides, the company switched off safety controls to reduce their expenses- including the MIC tank cooler that would have lessened the severity of the gas leak. The number of casualties was high due to the dense population in the Bhopal area, said to be more 900,000 and a warning siren that was started was immediately put off allegedly to prevent panic.
Most of the Bhopal residents were asleep when trouble began at the pesticide plant and many only woke up because they heard their children coughing from the fumes. As the residents woke up, they felt a burning sensation at the throat while some chocked from the smoke. People ran in all directions, unsure of which way to go, amidst the confusion, families became separated and many people fell unconscious and were trampled upon (Rosenberg, 2011).
Effects on the Environment
Even before the gas leak, the area surrounding the plant was used for depositing toxic chemicals and this led to the abandoning of wells in the vicinity of the plant in 1982. During the leak, nearly 27 tons of MIC gas escaped into the air and spread over the heavily populated city of Bhopal, spreading over a 30 square mile area.
The plant was closed between 1985 and 1986, during which most of the pipes and drums were sold off, however, the MIC and pesticide tanks are still in the site, as well as several tanks used to store various residues (Broughton, 2005). These tanks have worn out and the isolated material is falling out and is being dispersed into the surrounding water systems.
The isolated material contains several heavy and/or toxic elements that include naphthol, nickel, lead, mercury, and other hydrocarbon compounds such as hexachlorobenzene, most of which can cause nervous system breakdown, liver and kidney infections and perhaps cancer in the coming years. In fact, several studies have indicated that the water and soil in the area are highly polluted (Broughton, 2005).
Today, the location and its environs are still polluted with thousands of tons poisonous material, these have found their way into water systems that are used by the local population.
A recent visit by the BBC revealed that some wells in the area even contain nearly 500 times the recommended limit of these pollutants, however, the locals continue to use this water as they have no other choice (Vickers, 2004). The population around the UCIL plant still suffers from various diseases not common among persons living in other areas (Morehouse & Subramaniam, 1986).
Broughton, E. (2005). The Bhopal disaster and its aftermath: a review. Environmental Health: A Global Access Science Source, Vol. 4, No. 6.
Morehouse, W., Subramaniam, M. A., and the Citizens’ Commission on Bhopal. (1986).
The Bhopal tragedy: what really happened and what it means for American workers and communities at risk. NJ: Council on International and Public Affairs.
Rosenberg, J. (2011). 1984 – Huge Poison Gas Leak in Bhopal, India. Retrieved
February 14, 2011, from http://history1900s.about.com/od/1980s/qt/bhopal.htm
Vickers, P. (2004). Bhopal ‘faces risk of poisoning’. Retrieved February 14, 2011, from