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8829 Chemical accident in India with methyl isocyanate (mic)
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General accident information
Class/Quality * * * * *
Year 1984
Summary Run away process in storage
Tank of chemical factory which
Had a tremendous effect: inju-
Red people and their posterit
Country IND
Activity STORAGE
Chemicals Carbon dioxide (gas), Methyl isocyanate (mic)
Cause Management-failure
Fatalities/Injuries 8000 / 200000
Occurrences or events Burst/Rupture, Chemical reaction, Clean, Cooling,
Cooling, Defective-working, Defective-working, Fire fighting/Emergency response,
Management-failure, Management-failure, Management-failure, Management-failure,
Management-failure, Management-failure, Overheating, Overpressure,
Penetrate/Puncture, Pollution/Contamination, Release, Run-away-reaction,
Full accident information 
download accident report Click here to view a document containing the full accident information

Country: INDIA (IND)
Date : 1984 1203

One of the biggest chemical disasters in history took place in an Indian city. Overnight, 27E+3/kg of deadly gas leaked into the atmosphere from a pesticide plant, a USA-based chemical company. An estimated 8000 died within the first three days after the disaster and hundreds of thousands more were injured.

The incident involved the release of 36 tonnes of methyl isocyanate (MIC) from storage tanks during the night.
MIC was an intermediate in the production of Carbamoyl, the active agent in the pesticide Sevin. The MIC was stored in two refrigerated underground tanks, due to MIC being unstable. A third tank was in place to take off-specification MIC. Originally the plant was designed to receive Carbamoyl and process it into Sevin.
During the 1970s local Carbamoyl production commenced, involving the production and storage of MIC. In the 1980s demand for pesticides diminished rapidly, the plant was mothballed and staff were made redundant.
There was a common line to the Carbamoyl reactor on which a relief vent header was placed. Rejected MIC was recycled to the tanks and contaminated MIC passed to a vent gas scrubber (VGS) for neutralisation. Each MIC tank had local and control room temperature and pressure instrumentation, a local level indicator and an alarm. Other safety items included a limited capacity flare system, fixed water monitors and refrigeration units on the MIC tanks. The flare could be used in combination with the VGS for larger releases. The refrigeration system which cooled the MIC in the refrigerated tanks was taken out of service in June 1984 and its refrigerant removed.
The day before the incident the second-shift production superintendent ordered the MIC plant supervisor to flush out the pipework with water. Isolation that should have preceded the operation was neglected, allegedly due to redundancies in the maintenance department a few days earlier. Amongst other possibilities the water used for flushing may have found a sneak path to one tank.
At 2330 hours operators noticed MIC and dirty water being released from the downstream side of the MIC tanks. By 0015 hours the pressure in the tank had risen to 207/kPa, minutes later it read 379/kPa, the top of the scale. In the control room an attempt was made to start the VGS and the plant superintendent was called. On arrival he ordered the shutdown of the plant. The water sprays were turned on but only reached 15/m in height. The MIC was released at 33/m. An attempt was made to start the refrigeration system; this failed due to the lack of coolant. The toxic gas alarm was sounded to warn the local community. This was turned off a few minutes later, however, leaving only the plant siren to warn workers. It was reported that the earlier siren caused confusion among the people because those living in the neighbourhood rushed into the streets intending to put out what they thought to be a fire in the plant. The workers fled in the opposite direction to the toxic cloud.
The relief valve remained open for 2/hours. A tri-phase mixture of gas, entrained liquids and solids was released at a temperature of over 200/C and pressure of over 1241/kPa.

Following the disaster, the company compounded the problem by leaving the site without sufficiently cleaning up. Toxic chemicals have since leaked into Bhopal???s ground water and drinking wells, where they remain today.
Well over 12000 have died from exposure-related illnesses. Survivors continue to suffer. The longer-term health impacts of the incident are still emerging. Cancer rates in the area are rising at alarming rates and a second generation of children continues to be affected by deformities and physical abnormalities.
The situation remains divisive. The local population - and a growing international community ??? continue to demand the justice and compensation that most feel was never adequately provided.

Failings in technical measures
The flare system was a critical element within the plant???s protection system. However, this fact was not recognised as it was out of commission for some three months prior to the accident.
Plant Modification/Change Procedures:
HAZOP, identification of safety critical elements Hazards associated with runaway reactions in a chemical reactor are generally understood. However, such an occurrence within a storage tank had received little research.
Reaction/Product Testing: laboratory testing
The ingress of water caused an exothermic reaction with the process fluid. The exact point of ingress is uncertain though poor modification/maintenance practices may have contributed.
Design Codes - Plant: ingress of unwanted material
Maintenance Procedures: training and competence levels
Plant Modification/Change Procedures: HAZOP
The decommissioning of the refrigeration system was one plant modification that contributed to the accident. Without this system the temperature within the tank was higher than the design temperature of 0/C.
Plant Modification/Change Procedures: HAZOP, decommissioning procedures
The emergency response from the company to the incident and from the local authority suggests that the emergency plan was ineffective. During the emergency operators hesitated when to use the siren system. No information was available regarding the hazardous nature of MIC and what medical actions should be taken.
Emergency Response/Spill Control: site emergency plan, emergency operating procedures/training.

There were four long-term factors that contributed greatly to the incident:
1. Unsafe location.
The plant was located extremely close to densely populated areas of Bhopal. It was just 1.5/km from the city???s main rail station and 1/km from the bus station. In India there are zoning regulations to prevent situations like this. And at the time the plant was built, one senior government official had objected to the location. But these objections were ignored for political reasons and the company was given special permission to set up operations.
2. Double standards in design.
The company also had a MIC (methyl isocyanate) plant in the USA. The design of the USA based plant could not have been more different from the MIC plant in India. In India, substandard materials were used, available safety equipment was limited, much larger tonnages of the toxic and reactive chemical (MIC) were stored over longer periods, and there was no planning for a worst-case scenario. Also, the technology sent for use in the plant was unproven.
The Indian government was not aware of these double standards in plant design. Internal company documents have since emerged, admitting knowledge of these and other shortcuts.
3. Low standards of maintenance.
As an example, temperature and pressure were monitored once every 8/hours in the plant. This contrasts with the continual monitoring in the USA plant. Also, alarm systems in the USA are computerised and fully automatic ??? in Inida they were manual.
4. Workforce reductions and other cost cutting measures.
The company headquarters in the USA demanded an 8E+6 USA dollars decrease in costs of the MIC plant project in the early 1980s so that the company could continue to hold a majority stake in the Indian subsidiary. The plant???s workforce was reduced by about 50% between 1980 and 1984. Other highly unsafe measures included, for example, cutting down on the essential refrigeration systems and reusing corroded safety valves.
5. Precursors
Internal documents now available reveal that the company was aware of the risks. Safety audits as early as 1982 showed major hazards.

The combination of these factors created the conditions that led to the accident ??? directly caused when water entered an MIC tank through leaking valves. The water in the tank caused an exothermic reaction.
The Indian government has an inspectorate to try to prevent such situations, but it is totally understaffed. Each factory inspector has responsibility for 2000???3000 plants. In practice it is impossible to sufficiently enforce regulations.

Initially ??? the morning of the disaster - the response was anger. A lot of anger. People did not know what was being produced in the plant and even for a long time after the disaster the company was not sharing the correct information. Initially the company said the gas that escaped was only tear gas.
Twenty years on people continue to struggle. But their demands are still the same as they were immediately after the disaster: justice and the means to live a life of dignity, free of disease.
The demand for justice is not about retribution as many think. It is very much ???deterrent??? justice ??? to ensure that other corporations don???t do the same in the future. If the company gets away with murder, other corporations might think they can as well. This endangers the lives of people all over the world, but particularly in developing countries.

There was a monetary settlement of some 470E+6 USA dollars arranged between the Indian government and the company following the disaster. Initially the government had claimed upwards of 3E+9 USA dollars, but in the end chose to settle for a fraction of the sum without any consultation with the victims. This settlement was seen all over the country as a humiliating betrayal of the people. It showed our government is more interested in protecting corporations than its own people.

In the immediate aftermath the entire world wept for Bhopal. There was support abroad, but it soon waned. It has only been in recent years that a concentrated international campaign has started for justice. Particularly in the last three to four years, groups such as student groups, trade unions and those groups who have been impacted by similar disasters have become more and more involved.

The company merged with another chemical company in February 2001. Survivor organisations are demanding that this company accept the liabilities of the disaster - asking for long-term medical care, economic rehabilitation and remediation of the remaining poisons in the soil and ground water. They also want this company to ensure that former company faces trial in the ongoing criminal case on the disaster. In line with the tradition of "double standards", the company has accepted the former company's pre-merger liabilities in the USA but refuses to accept Bhopal liabilities.

How have things changed following the disaster? Could another incident like the one in Bhopal occur in India?

Conditions today are worse than at the time of the Bhopal incident. If anything, the likelihood of another disaster has increased.

One factor that contributed to the disaster in the Bhopal plant was the lack of local-level control. Everything that happened in the factory was dictated by headquarters in the USA. Even if a worker wanted to change a gasket, he had to ask headquarters.
This was possible in part because the American corporation held the majority of the plant???s shares. At the time, Indian law prevented foreign companies from holding majority shares of companies in India. The company, however, had special status ??? it was an exception to the rule.

Today, that rule no longer exists. Any company can hold majority shares of an Indian company. This can lead to the same type of situation where local interests are perhaps not taken into account.

Also, workers??? rights were much stronger at the time of the disaster. Today, workers have no rights to demand safer working conditions. And as we have seen, most environmental problems start out as occupational health problems.

The government is willing to sacrifice the lives of ordinary people to attract businesses to India. More and more countries and companies are targeting countries like India and China for the chemical industry. India now has a growth rate in the chemical industry that is three times the global growth rate.

Lessons learned
Poor isolation of storage tanks and no valve position indicators fitted.
Excessive routes available for water to enter MIC storage tanks.
Large scale, long-term storage of hazardous process material under improper conditions.
Poor zoning policy.
Inadequate preliminary evaluation of the process leading to the production of hazardous intermediates.
Safety systems were inadequate and not functioning.
Inadequate modification and evaluation process.
Poor maintenance of pipework, valves and instrumentation.
Failure to manage change and select inherently safer process routes.
Lack of safety training and technical experience.
Absence of emergency procedures.

So far, other countries have already learned more lessons from this incident than India has. For example, following the disaster the USA passed a law requiring companies to disclose chemical emissions to the community. And England and Scotland are in the process of enacting laws on corporate manslaughter.

In general, the most important lessons that can be learned are:
Corporations should make all information available to officials and the community before anything is set up.
Residents in the neighbouring communities should have the right to periodically inspect factories and obtain safety and heath information;
A wide "precautionary principle" should be used when decisions about plant location, technology and product choice are made; ??
Adequate emergency medical response care should be available for a worst-case scenario;
A good city evacuation plan should be prepared; and ??
In the event of a disaster infrastructure should be established to support long-term monitoring and research, not just a short-term clean up. The effects of disasters like these can be felt generations later.

Une compagnie am??ricaine implante en 1969 une usine de fabrication d'un puissant insecticide : le Sevin. L'installation comprend 3 r??servoirs de 60 m3 (50 t) d'isocyanate de m??thyle (MIC) liquide (E610, E611 et E619), chacun ??tant reli?? ?? diff??rents syst??mes de s??curit?? : installation de r??frig??ration, laveur de gaz d'??chappement, torch??re et dispositif de pulv??risation d'eau. Le minist??re indien a autoris?? l'usine ?? produire 5000 t/an de Sevin. Pour faire face ?? la concurrence sur le march?? des insecticides et ?? un d??ficit budg??taire de l'usine de 4 millions dollars, la soci??t?? m??re d??cide d'arr??ter sa production locale de Sevin, de supprimer de nombreux postes d'encadrement (maintenance notamment) et de faire fonctionner le site au moindre co??t... L'accident a lieu dans la nuit du 2-3/12/1984. Apr??s le nettoyage de canalisations, de l'eau p??n??tre dans le r??servoir E610 et initie plusieurs r??actions en cha??ne conduisant ?? des ??l??vations de temp??rature (200??C) et de pression (13,79 bar). En 2 h, une soupape de s??curit?? laissera s'??chapper 23 ?? 42 t de MIC et autres gaz toxiques selon les sources. Plusieurs syst??mes de s??curit?? se sont av??r??s d??faillants: r??frig??ration ?? l'arr??t (06/84), laveur de gaz d'??chappement hors service (23/10/84), torch??re hors d'usage (quelques jours avant l'accident), indicateurs de temp??rature, pression et niveau de liquide dans la cuve d??fectueux, rideau d'eau pas assez puissant. Les ??manations toxiques font de nombreuses victimes parmi la population: 1754 ?? 2500 morts et 170 000 ?? 600 000 intoxiqu??s selon les sources. Plus de 4000 animaux (b??tails, chiens, chats, oiseaux) sont morts. Une pollution chronique aggrav??e par les rejets toxiques affecte de longue date la population. Fin 1998, le bilan des victimes s'est allong?? ; 16000 morts sont d??nombr??s et 15 ?? 20 individus d??c??dent chaque mois des suites de l'accident. Lanc??e en 1987, la proc??dure judiciaire conna??t plusieurs rebondissements. Initialement poursuivis pour homicide, les 8 pr??venus (7 Indiens et un Am??ricain, le pr??sident de la compagnie) ont b??n??fici?? en 1996 d'un arr??t de la Cour supr??me indienne. La plus haute instance judiciaire avait alors requalifi?? les faits en homicide par n??gligence, un d??lit puni au maximum d'une peine de deux ans de prison. En1989, L'exploitant passe un accord avec le gouvernement indien: l'industriel verse un d??dommagement de 470 millions de dollars, contre l'abandon de toute poursuite. Le 7 juin 2010, le tribunal de premi??re instance condamne ?? deux ans de prison et 100000 roupies d'amende (1751 euros) 7 personnes, jug??es responsables de la catastrophe. Une amende de 10000 dollars (8354 euros) est inflig??e ?? la filiale indienne de l'exploitant pour n??gligences. Le PDG de l'entreprise ?? l'??poque, d??clar?? ??en fuite?? par la cour, n'a pas ??t?? nomm?? lors du verdict.

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