Isocyanate Poisoning

CDC hazardous chemical category choking/lung/pulmonary agent 

Breath sounds - wheezes Breath sounds - crackling (rales) 

ant - pain, nonpleuritic rest Consciousness - loss, sudden (syncope) 

Cough - acute nonspecific Eyes, conjunctivae - injected Eyes, cornea - damage Eyes, lids - swelling (edema) 

light sensitivity - inceased (photophobia) Eyes - irritation 

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Methyl bromide poisoning Methyl isocyanate poisoning Omsk hemorrhagic fever Osmium tetroxide poisoning Pertussis... 

Cyanide antidotes such as sodium nitrite and sodium thiosulfate were not effective in combating methyl isocyanate poisoning (Bucher et al. 1987a,b Vijayaraghavan and Kaushik 1987). Atropine and ethanol were also ineffective. 

The worst disaster in the history of the chemical industry occurred in Bhopal, in the state of Madhya Pradesh in central India, on December 3, 1984. A leak of methyl isocyanate (MIC) from a chemical plant, where it was used as an intermediate in the manufacture of the insecticide car-baryl, spread beyond the plant boundary and caused the death by poisoning of more than 2,000 people. The official figure was 2,153, but some unofficial estimates were much higher. In addition, about 200,000 people were injured. Most of the dead and injured were living in a shanty town that had grown up next to the plant. 

A few additional points have also been raised by specific surface-science work concerning the catalytic reduction of NO. For instance, it has been widely recognized that the reaction is sensitive to the structure of the catalytic surface. It was determined that rough surfaces such as (110), or even (100), planes enhance NO dissociation over flatter (111) surfaces, and also favor N2 desorption instead of N20 production. On the other hand, NO dissociation leads to poisoning by the resulting atomic species, hence the faster reaction rates seen with medium-size vs. larger particles on model rhodium supported catalyst (the opposite appears to be true on palladium). Also, at least in the case of palladium, the formation of an isocyanate (-NCO) intermediate was identified... 

On 1st January 2000 the new regulations re-classifying isocyanates as resin components came into force. According to the new definitions TDI prepolymers with a clear TDI proportion of 1-7% must be rated as poisonous and provided with risk memoranda R23, R40 and R42/43. Clear TDI proportions of 0.1-1% must be rated as harmful... 

Potential Uses of These Polymers. We have studied the phenyl isocyanate modification of poly(vinyl alcohol) as a model system. Many uses exist for carbamates as medicines, pesticides and herbicides (67,68). For example, ethyl carbamate has been used to treat leukemia and multiple myeloma. Ethyl carbamate has also been used as an antidote for central nervous system poisoning by strychnine. The tranquilizer Meprobamate is a carbamate derivitive. Numerous pesticides and herbicides, such as Sevin and Propham, are also carbamate derivatives. Propham is isopropyl N-phenylcarbamate which bears a strong resemblence to the polymers of Equation 21, and this compound is used as a preemergence herbicide. Numerous other close analogs could be cited also. We might note also that the N-phenyl carbamoyl unit bears... 

Thus, immune-media ted responses can be immediate or delayed and localized or widespread. The response can be restricted to the area of exposure or can be systemic. Similar compounds may cross-react or produce very different responses. Many different foreign compounds can cause an immunotoxic response drugs such as penicillin, halothane, and hydralazine, industrial chemicals such as trimellitic anhydride and toluene di-isocyanate, natural chemicals such as pentadecylcatechol found in poison ivy, food additives such as tartazine, and food constituents such as egg white (albumen). 

Although the direct trimerization of alkyl isocyanates is facile, it is preferable to prepare these compounds in situ because the isocyanates are both expensive and poisonous (equation 79) (65BCJ1586). 

Methyl isocyanate (b.p. 39°C—often referred to as Bhopal gas ) is flammable and poisonous. 

Methyl isocyanate (MIC) is the smallest member of the isocyanate family and the most reactive and toxic of all. MIC was almost unheard of until the fateful night December 3, 1984, when nearly 30 metric tons of this poisonous chemical spewed out of the Union Carbide India Ltd (UCIL) pesticide plant within a period of 45-60 min (Jayaraman, 1984). Bhopal turned into a city of death , wrote the fortnightly India Today (December 30, 1984). The journal Nature (Opinion, 1984) vented its anger thus ... the anguish vividly carried round the world by the television cameras seems not to have matured into the anger, even hysteria, there would have been had the [Bhopal] accident occurred on the edge of a European city - or in Connecticut (the headquarters of Union Carbide was in Danbury, Connecticut, USA). 

By the year 1956, more than 100 cases of illnesses and four cases of death due to poisoning by TDI were reported (Baader, 1956). In view of the increased use of isocyanates, the National Institute of Occupational Safety and Health, USA, projected as early as 1978 that approximately 50,000 to 100,000 workers would be exposed to these chemicals within 2 years (NIOSH, 1978) this estimate was based on exposure at the workplace in polyurethane production, upholstery work, wire coating, and spray painting in the absence of any accidental spill (Axford et al, 1976 Editorial, 1966 Fuchs and Valade, 1951 Hill, 1970 Williamson, 1965). 

SAFETY PROFILE Poison by inhalation. Moderately toxic by ingestion. Experimental reproductive effects. When heated to decomposition it emits toxic fumes of NO.. See also ESTERS and ISOCYANATES. 

Flammable Liquid, Poison (UN 2478) SAFETY PROFILE Poison by intravenous route. A flammable liquid. When heated to decomposidon it emits toxic fumes of NOx. See also ISOCYANATES. 

Flammable Liquid, Poison DOT Class 6.1 Label Poison DOT Class 6.1 Label Poison, Flammable Liquid DOT Class 3 Label Flammable Liquid, Poison SAFETY PROFILE Poison by intravenous route. A flammable liquid when exposed to heat or flame, can react vigorously with oxidizing materials. When heated to decomposition it emits toxic fumes of NOx. See also ISOCYANATES. 

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