Bhopal toxic release accidents

The risk of toxic release accidents into the atmosphere or watercourses is very real, and there have been many examples. Four very notable and well-known examples - Seveso, Bhopal, Mississauga and the Sandoz chemical spill into the Rhine - are briefly outlined below, together with a more detailed description of a less well-known incident. 

Serious accidents (such as Bhopal) emphasize the importance of planning for emergencies and of designing plants to minimize the occurrence and consequences of a toxic release. Toxic release models are routinely used to estimate the effects of a release on the plant and community environments. 

Although toxic releases, in general, are not the principal cause of major accidents (relative to fire and explosion) associated with the chemical industry, they are a just cause of "considerable public apprehension" [1327a]. This concern has been compounded by an event which occurred in Bhopal, India in December 1984, in which over 2500 people were killed by a single toxic release of methyl isocyanate. 

In addition to the amounts of chemicals released to the environment through accidents, the U. S. Toxic Release Inventory shows the release of 2.43 billion lb into air, land, or water in 1996,169 down from 3.21 billion lb in 1992.170,171 (The data is available on a number of Internet sites, including www.epa.gov/opptintr/tri.) The total decline since the law became effective in 1987 has been 46%. This right-to-know law was enacted in the aftermath of the Bhopal accident. It now covers nearly 650 chemicals out of about... 

This accident occurred in the early hours of December 3, 1984 at the Union Carbide pesticide plant in Bhopal, India. The accident released at least 30 tons of a highly toxic gas called methylisocyanate (MIC) as well as a number of other poisonous gases that resulted in about 4000 deaths and 500,000 injuries [1]. 

There are three types of TAP emissions continuous, intermittent, and accidental. Both routine emissions associated with a batch process or a continuous process that is operated only occasionally can be intermittent sources. A dramatic example of an accidental emission was the release of methyl isocyanate [624-83-9] in Bhopal, India. As a result of this accident, the U.S. Congress created Tide III, a free-standing statute included in the Superfund Amendments and Reauthorization Act (SARA) of 1986. Title III provides a mechanism by which the pubHc can be informed of the existence, quantities, and releases of toxic substances, and requires the states to develop plans to respond to accidental releases of these substances. Eurther, it requires anyone releasing specific toxic chemicals above a certain threshold amount to aimuaHy submit a toxic chemical release form to EPA. At present, there are 308 specific chemicals subject to Title III regulation (37). 

The previous chapter described the consequences of a nuclear reactor accident. Chemical process accidents are more varied and do not usually have the energy to melt thick pressure vessels and concrete basemats. The consequences of a chemical process accident that releases a toxic plume, like Bhopal did, are calculated similarly to calculating the dose from inhalation from a radioactive plume but usually calculating chemical process accidents differ from nuclear accidents for which explosions do not occur. 

In 1988 producers of basic industrial chemicals, plastics, and fibers in tlie United States increased tlieir sales at least 10% to about 90 billion (exclusive of foreign subsidiaries) primarily as a result of increased demand at home and abroad. Along witli die increase of chemical production safety and accident prevendon liave become more critical and essential. Such dramadc releases of toxic chemicals as diose tliat occurred in Bhopal and at Three Mile Island have lieightened publie eoneem for die integrity of process facilities dial liandle liazardous materials. 

On December 3, 1984, a toxic gas release from a pesticide plant in India killed nearly 3000 people and injured at least 100,000 others. The chemical that leaked was methyl isocyanate, a chemical intermediate that was supposed to be stored in a cooled bunker near the plant s outer boundary. The vapor is highly toxic and causes cellular asphyxiation and rapid death. Despite engineering and procedural provisions to prevent its release, a total system breakdown resulted in the release of 40 tons of the deadly material into the densely populated community of Bhopal. Because of this incident, the plant was dismantled and ultimately the parent corporation. Union Carbide, was forced to make a number of organizational changes. The occurrence is considered by many to have been the most tragic chemical accident in history. 

Methyl isocyanate was the toxic agent involved in the most catastrophic industrial accident of all time, which took place in Bhopal, India, on December 2, 1984. This accident occurred when water got into a tank of methyl isocyanate, causing an exothermic reaction that built up pressure and ruptured a safety valve. This resulted in the release to the atmosphere of 30 to 40 tons of the compound over an approximately 3-h period. Subsequent exposure of people resulted in approximately 3,500 deaths and almost 100,000 injuries. 

One of the worst industrial accidents occurred in Bhopal, India, on December 2 and 3, 1984. It was due to the leakage of methyl isocyanate (MIC) released from the Union Carbide pesticide manufacturing plant. More than 3,000 people who resided in areas adjacent to the manufacturing plant died within a few hours after exposure to MIC. Death was attributed to severe pulmonary toxicity, followed by... 

On December 3 and 4, 1985, a chemical release causing a massive toxic gas cloud occurred at the Union Carbide India, Ltd, plant in Bhopal, India. (Union Carbide is now a part of The Dow Chemical Company.) The process involved used methyl isocyanate (MIC), an extremely toxic chemical, to make Sevin, a pesticide. According to various authoritative reports, about 1,700-2,700 (possibly more) people were killed, 50,000 people were affected seriously, and 1,000,000 people were affected in some way. The final settlement may involve billions of dollars. It was one of the worst industrial accidents in history. The accident occurred when about 120-240 gallons of water were allowed to contaminate an MIC storage tank. The MIC hydrolyzed, causing heat and pressure, which in turn caused the tank rupture disk to burst. 

Materials that become more hazardous when contacted with water comprise another important class of incompatible materials. For example, carbonyl sulphide (COS) and calcium sulphide (CaS) both release toxic H2S on contact with water. Dry powders of sodium or potassium cyanide release toxic HCN in the presence of moisture. Care must be taken to prevent such materials from coming into contact with water during processing and storage. The 1985 Bhopal accident was started by a runaway reaction involving a water-sensitive chemical. 

The gas leak had devastating effects on the exposed population. Over 200000 residents (that comprised about one-fourth of the total population of city of Bhopal) were exposed to MIC and other related toxic gases released from the plant. Most of these residents were from the poor class and were living in the immediate surroundings of the Union carbide plant. The human mortality is estimated to be between 2500 and 5000 from this accident. Respiratory failure due to MIC inhalation was the principal cause of death. MIC caused bronchial necrosis and pulmonary edema. Within the first 24 h after the accident, 90 000 patients were admitted in local hospitals and clinics with multiple symptoms of respiratory distress, breathlessness, choking, cough, chest pain, and hemoptysis. Acute ophthalmic effects were also reported with severe eye irritation and watering of the eyes. 

On December 3, 1984, Bhopal, India, experienced a release of approximately 40 metric tons of methyl isocyanate (MIC) at the Union Carbide pesticide plant. Over 100,000 were injured and 3000 people were killed, and many more are likely to die from the long-term effects. The accident occurred around 12 40 a.m. local time, when most of the victims were sleeping. The dead included large numbers of infants, children, and older men and women. These age groups are often adversely impacted by toxic exposures. 

The world s worst industrial disaster occurred in Bhopal, India, in 1984 in which nearly 40 metric tons of methyl isocyanate was released from a pesticide plant killing over 3000 people. Most deaths resulted from pulmonary edema within 3 days of accident. Many follow-up studies indicated pulmonary, ophthalmic, neurological, reproductive, immunologic and hematologic toxic effects among the survivors. 

Thus far, discussion has centered on chemical compounds with a military application. Other highly toxic industrial chemicals also pose a potential risk to the military. The disaster in Bhopal, India, in December 1984, when an estimated 8,000 persons died and another 30,000 were injured from breathing methylisocyanate and chlorine released in an industrial accident, is just one of many examples of the devastating effect of poisonous gases.26... 

Toxicology MIC is extremely toxic. Exposure is by inhalation and skin absorption. MIC is an irritant (eyes, mucous membrane and skin) and a toxic at high concentrations that can cause death. It can damage by inhalation, ingestion and contact in concentrations as low as 0.4 ppm. MIC is considered to be a genotoxic that can cause chromosomal abnormalities (as shown by the Bhopal accident in India, when about 43,000 kilograms of MIC were released over a populated area in 1984, killing thousands of people) [58]. 

The Flixborough nylon plant accident in the UK (1974) was caused by an open-air explosion of a flammable gas released into the air. It killed the 28 plant employees present and caused extensive property damage in the surrounding area. The failure to perform a full technical assessment of a modification was given as the main cause of the event. The Seveso pesticide plant accident in Italy (1976) is well known for the dangerous release of dioxin due to poor plant safety features and to the underestimation of the possibility of a runaway reaction. The Bhopal incident in India (1984), at another pesticide plant, killed an estimated 4000 (although the total number is still unknown). This disaster was attributed to too large an inventory of toxic substances and to very poor staff attention to the operability of safety features. 

---