Methyl isocyanate storage

The study of the accidents in chemical facilities, during transportation, storage and others, the research of the chemical products, which are produced and stored, are important points in the preparation of the defence against chemical terrorism. An example of such an accident is the explosion at the Union Carbide pesticide manufacturing plant (Dec. 3, 1984), which scattered toxic methyl isocyanate (MIC) over the city of Bhopal, India. During the first few days up to 4000 people died of painful, harrowing deaths [10],... 

Methyl isocyanate (MIC) is a colorless liquid that must be stored in a cooled enclosure before it is subsequently used in the manufacture of carbamate, a common insecticide. MIC liquid is highly reactive in the presence of water and iron oxide, and it generates heat. In sufficient quantities, this heat may generate vapor, which, as explained previously, is highly toxic. Three adjacent bunkers were used for MIC storage. These were mounted in a berm and a refrigeration coil was used to ensure that the temperature did not exceed 5°C. A vent gas scrubber was used to prevent vapor escape, and despite a low operating pressure, a closed relief... 

Bhopal, the site of the largest chemical accident in the past 50 years, wasn t an explosion but rather an uncontrolled reaction. The plant in Bhopal, India, owned jointly by Union Carbide and the Indian government, was producing methyl isocyanate as an intermediate for a pesticide. Water was admitted into a storage tank containing this chemical, which caused it to hydrolyze and produce CO, HCN, and unreacted MIC, which spread downwind into a crowded slum nearby and caused many deaths and casualties. The desired reaction to synthesize MIC was... 

A number of chemicals, fortunately a limited number, become dangerous either when they are used wrongly, or when they are accidentally set free. Thalidomide, put on the market in 1957 by the German company Chemie Gruenenthal, was indeed a powerful sedative. But it took three years to perceive that when prescribed to pregnant women, it dramatically crippled the newborn children. The synthetic intermediate for insecticides, methyl isocyanate, which Union Carbide has used for years without incident in its West Virginia Institute plant, caused over 2,000 deaths when it escaped in 1984 from a storage tank in Union Carbide s Bhopal plant in India. 

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. 

The owner of tlie plant. Union Carbide Corporation, reported tliat tlie accident was "tlie result of a unique combination of unusual events." The methyl isocyanate (MIC) was driven out of a storage tank by pressure generated from a water-induced runaway polymerization reaction. The last batch of MIC put into the tank before the accident contained more chloroform tlian product specifications allowed. Cliloroform promotes the polymerization of MIC altliough cliloroform alone cannot react without the higli temperatures caused by tlie presence of water. The excess chloroform is one of tlie "unusual events" preceding tlie disaster, altliough the presence of water appears to be tlie primaiy culprit. 

On December 26, 1984 at 11 30 p.m, when the people of Bhopal, India, were preparing for sleep, a worker detected a water leak in a storage tank containing methyl isocyanate (MIC) at the Union Carbide Plant. About 40 tons of MIC poured from the tank for nearly 2 hours without any preventive measures being taken. The night winds carried the MIC into the city of Bhopal. Some estimates report 4000 people were killed, many in their sleep and as many as 400,000 more were injured or affected. 

The Bhopal incident (India, 1984) has dramatically outlined the high toxicity level of methyl isocyanate and moreover its very exothermic self-polymerization which requires extreme care during its production and storage (Ref. 270),... 

In Bhopal, India, a Union Carbide storage tank containing methyl isocyanate (CH3NCO, a component used for the production of insecticide) leaked, resulting in injury and death to thousands of people. The American Occupational Saftey rules specify that workplace conditions are to be limited to concentrations less than 0.02 ppm of this compound. Assume ideal gas behavior. What is this concentration in mg/m at 20 C and atmospheric pressure ... 

In 1982, the European Union s Council Directive 82/501/EEC on the major-accident hazards of certain industrial activities, also known as the Seveso Directive, was adopted. The Directive was mostly designed to promote information flow and created the requirement that each Member State (i.e., each country belonging to the European Union) appoint a Competent Authority to oversee safety issues. The Seveso Directive was amended twice, following major accidents at the Union Carbide chemical factory in Bhopal, India in 1984 (a leak of methyl isocyanate caused thousands of deaths), and at the Sandoz chemical warehouse in Basel, Switzerland in 1986 (fire-fighting water contaminated with mercury, organophosphate pesticides and other chemicals caused massive pollution of the Rhine River and the death of hundreds of thousands of fish). Both amendments, broadened the scope of the Directive, in particular to include the storage of dangerous substances. 

Figure 1.5 Methyl isocyanate (MIC storage) tank used in the Bhopal Union Carbide process. Source adapted from Reference [31].

In December 1984 water leaked into a storage tank and reacted to cause an increase in pressure that subsequently blew the tank. Around 41 tonnes of methyl isocyanate was released into the atmosphere and rained back down on the local population. 

After the Bhopal accident, new regulations were introduced in almost all countries to limit the amount of methyl isocyanate (MIC) that may be stored in a plant. The EU allows a maximum of half a tonne storage on site - around 67 toimes were stored at the Bhopal facility. The use of MIC could be avoided by changing the order of synthesis, as illustrated in the alternative route reported in Figure 1.9 [67]. 

Release from a bulk storage tank If TIC is known and listed in this chart use exclusion areas shown Phosgene Hydrogen Cyanide (hot climate) Hydrogen sulfide Methyl isocyanate 50 2 Km 5 Km... 

Methyl isocyanate, CH3NCO, was made infamous in 1984 when an accidental leakage of this compound from a storage tank in Bhopal, India, resulted in the deaths of about 3,800 people and severe and lasting injury to many thousands more, (a) Draw a Lewis structure for methyl isocyanate, (b) Draw a ball-and-stick model of the structure, including estimates of all the bond angles in the compound, (c) Predict all the bond distances in the molecule, (d) Do you predict that the molecule will have a dipole moment Explain. 

During the night of December 2-3,1984, the worst industrial disaster in history occurred at Union Carbide s plant in Bhopal, Madhya Pradesh, India. Methyl isocyanate (MIC) liquid, an intermediate used in making Sevin, Union Carbide s name for the pesticide carbaryl, came into contact with water, boiled violently, and turned into MIC gas. Unchecked by various safety systems, tons of highly toxic MIC gas escaped from storage tank E610. A cloud of MIC gas descended upon shantytowns just outside the plant, as well as on Bhopal city. Estimates of the death toll from exposure to the gas, immediately or in the first 2 weeks, range from 2000 to 8000 or more. If those who died months or years later from MIC exposure are counted, the death toll rises to between 20,000 and 30,000. More than 500,000 people suffered injuries from exposure to the gas and its effects on the environment. ... 

In December 1984, Union Carbide workers were performing maintenance work on pipes connected to a storage tank of methylisocyanate at a pesticide plant in Bhopal, India. The plant was built beside a residential area. The maintenance included washing out the pipes with water, which, due to faulty valves and unwise modifications to the plant design, made its way into the storage tank. Methyl isocyanate reacts exothermically with water, and the heat generated caused a dramatic temperature and pressure rise, which was undetected by the plant operators. The refrigeration unit, intended to keep the tank cool, had been shut down about a year earlier. By 10 45 pm, the plant... 

The Bhopal disaster, in terms of loss of life and human injury, is the most serious disaster in the history of the chemical and process industries. It took the form of a runaway polymerization of a highly toxic substance — methyl isocyanate (MIC). This took place not in a reactor, but in a storage tank. 

The main derivative of 1-naphthol is carbaryl, which is produced by the reaction of 1-naphthol with methyl isocyanate. Methyl isocyanate, a toxic liquid boiling at 38 °C, is obtained, among other methods, by the reaction of phosgene with methylamine. Because of its toxicity, it should only be stored for short periods to avoid possible risks during storage (Bhopal accident). 

December 3,1988. Bhopal, India. Many describe this event as the world s worst industrial tragedy. During predawn hours at the Union Carbide plant, as much as 40 tons of methyl isocyanate gas leaked from a storage tank at the chemical plant. The gas settled over a 15 square mUe area populated by more than 200,000 people. Local residents call this Devil s Day. The chemical release killed more than 3,000 and injured more than 20,000. Some reports state that over 50,000 people received medical treatment the first day. Many injuries involved damage to eyes and mild to severe pulmonary disorders. Health issues remain 30 years later for many victims. ... 

Phosgene is a very toxic chemical, and storage of it in large quantities poses a serious safety problem. A continuous tubular reactor is developed to make this chemical for immediate consumption. So an inventory of only 70 kg of gaseous phosgene has to be maintained when compared to an inventory of 25,000 kg of the liquid in the storage in the old batch process. Methyl isocyanate (MIC), the infamous chemical that was released at Bhopal, can be generated and immediately converted to the final pesticide in a tubular reactor that will contain a total inventory of less than 10 kg of MIC. 

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