Potential exposure phosgene

Most of the materials used in the manufacture of chemicals are poisonous, to some extent. The potential hazard will depend on the inherent toxicity of the material and the frequency and duration of any exposure. It is usual to distinguish between the short-term effects (acute) and the long-term effects (chronic). A highly toxic material that causes immediate injury, such as phosgene or chlorine, would be classified as a safety hazard. Whereas a material whose effect was only apparent after long exposure at low concentrations, for instance, carcinogenic materials, such as vinyl chloride, would be classified as industrial... 

Recent studies on rats have shown some therapeutic potential of the alkaloid colchicine [749aa,749ab]. Administration by injection both before or after exposure to phosgene (0.5 p.p.m. for 1 h) significantly reduced both lung injury and mortality. It is believed that... 

It has been estimated (although without substantiation) [1484] that some ten thousand workers were potentially at risk to occupational phosgene exposure during its manufacture or use in 1976. In addition, exposure to phosgene can result from the decomposition of various chlorinated organic materials as described in Section 3.3. Risks to the populace, as a result of catastrophic emissions, are described in Section 3.6. 

This innovative research has resulted in a commercial DuPont process that makes MIC and converts it in-situ to an agrichemical product. Consequently, the potential for exposure is greatly reduced. This trend in in-situ manufacture and derivatization is clearly the way of the future for hazardous chemicals. Non-phosgene routes to isocyanates, and use of solid acids to avoid HP and H2SO4 as alkylation catalysts are other examples of research in progress to minimize fur er the use of hazardous materials. 

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