Chlorine hazards risk assessment

An overview is provided of ongoing risk assessments on halogenated phosphate ester flame retardants in Europe. On the basis of the so-called second and fourth Priority lists on Existing Chemicals (Council Regulation No793/93) three chlorinated phosphate ester flame retardants are selected. The selection is based on their hazard profile, volume and use pattern. The three substances involved are TCPP, TDCP and TCEP (Antiblaze V6 from Albemarle is also involved but, due to confidentiality, is not discussed. An outline is provided from a European point of view on topics such as methodology of risk analyses, data-gaps and worst case approach, industry involvement, downstream participation and possible impact of final report on industry. 2 refs. 

PCBs (polychlorinated biphenyls) A family of chemicals composed of biphenyl molecules that have been chlorinated to varying degrees, performance assessment A type of risk assessment in which the potential long-term impacts of hazardous waste disposal on human health and the environment are evaluated for the purpose of determining whether disposal of specific wastes at specific sites should be acceptable, persistence The length of time that a contaminant persists in the environment. 

New Jersey adopted a Toxic Catastrophe Prevention Act in 1986, which requires risk assessment by companies.167 The Kanawha Valley Hazardous Assessment Project in West Virginia developed worst-case scenarios for 12 chemical plants in the area.168 The chemicals studied included acrylonitrile, vinylidene chloride, butyl isocyanate, methylene chloride, chlorine, phosphorus trichloride, hydrogen sulfide, methyl isocyanate, phosgene, ethylene oxide, sulfur trioxide, and others... 

The continuing preoccupation with PCBs is to some extent an exercise in futility since nothing can be done to alleviate the problem. More effort should be made toward hazard identification, risk assessment, and possible replacements for organohalogen compounds, such as the halogenated diphenyl ethers and chlorinated and brominated cycloparaffins, that are still being used and released into the environment and for which there are many data gaps. 

Risk assessments were first developed by the conunercial nuclear power industry, but they are now being used extensively in the chemical process industry. The advantage of quantitative risk assessment is that it not only identifies hazards, it also gives you a way to decide how to manage those hazards. This becomes particularly important if a plant wants to better understand how a chlorine spill at a wastewater treatment plant would affect surrounding neighborhoods. The tool allows you to add on other models such as toxic cloud dispersion models. 

Mere destruction of the original hazardous material is not, however, an adequate measure of the performance of an incinerator. Products of incomplete combustion can be as toxic as, or even more toxic than, the materials from which they evolve. Indeed, highly mutagenic PAHs are readily generated along with soot in fuel-rich regions of most hydrocarbon flames. Formation of dioxins in the combustion of chlorinated hydrocarbons has also been reported. We need to understand the entire sequence of reactions involved in incineration in order to assess the effectiveness and risks of hazardous waste incineration. 

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