Toxic chemical risk analysis

Each application has revealed new aspects that had not been considered previously (Table I). Nevertheless, the examples share one characteristic common to toxic chemical risk analysis an acceptable exposure level must be combined with a relationship between source concentration and estimated degree of exposure. This concept has been published previously(1,2,3) ... 

Toxic chemical risk assessment is based on two separate analyses an analysis of the inherent harmfulness (toxicity) of the chemical of concern, and an estimate of the degree of contact that humans or other organisms will have with the chemical (exposure). A risk assessor identifies the toxic effect or effects known to be associated with a chemical. The assessor also estimates the exposure of an at-risk population to the chemical. The magnitude of the exposure makes it possible to predict the likelihood that a particular toxic effect will occur. 

The Chemical Process Industry (CPI) uses various quantitative and qualitative techniques to assess the reliability and risk of process equipment, process systems, and chemical manufacturing operations. These techniques identify the interactions of equipment, systems, and persons that have potentially undesirable consequences. In the case of reliability analyses, the undesirable consequences (e.g., plant shutdown, excessive downtime, or production of off-specification product) are those incidents which reduce system profitability through loss of production and increased maintenance costs. In the case of risk analyses, the primary concerns are human injuries, environmental impacts, and system damage caused by occurrence of fires, explosions, toxic material releases, and related hazards. Quantification of risk in terms of the severity of the consequences and the likelihood of occurrence provides the manager of the system with an important decisionmaking tool. By using the results of a quantitative risk analysis, we are better able to answer such questions as, Which of several candidate systems poses the least risk Are risk reduction modifications necessary and What modifications would be most effective in reducing risk ... 

Use Joseph F. Louvar and B. Diane Louvar, Health and Environmental Risk Analysis Fundamentals with Applications (Upper Saddle River, NJ Prentice Hall, 1998), pp. 287-288, to find the toxicity levels (high, medium, low) for the inhalation of toxic chemicals. 2-29. Use Louvar and Louvar, Health and Environmental Risk Analysis, pp. 287-288, to find the toxicity levels (high, medium, low) for the single dose of a chemical that causes 50% deaths. 

Hattis, D., L. Erdreich, and M. Ballew. 1987. Human variahility in susceptibility to toxic chemicals - A preliminary analysis of pharmacokinetic data from normal volunteers. Risk Anal. 7 415 26. 

As risk assessment becomes more sophisticated and is extended to more chemicals, it will also be extended to smaller and smaller risks. Since it is not possible to regulate all risks, an important use of risk analysis must be to decide which chemicals should be regulated and to what degree. Under the Tbxic Substances Control Act (TOSCA), all new chemicals must be considered. The prioritization scheme for chemical testing is based upon a set of dichotomous criteria, toxicity, chemical reactivity, etc., which involve qualitative rather than quantitative risk analysis. As procedures for more quantitative analysis become available, the prioritization scheme will become more precise, (NAS/NRC, 1984). 

Introduction to Risk Analysis of Fine Chemical Processes 1.4.1.3 Toxicity... 

Phimister, J. et al., Near-Miss Incident Management in the Chemical Process Industry, Risk Analysis, Vol. 23, No. 3,2003 Toxic Catastrophe Prevention Act (TCPA) N.J.S.A. I3 IK-I9 et seq. 

In assessing risks posed by toxic chemicals, exposure (see exposure analysis below) refers to mechanisms of direct contact, ingestion, inhalation, or indirect accumulation through the consumption of contaminated food. The concept of exposure has been expanded to include analogous pathways and mechanisms that define the intersection in space and time of other stressors with individual organisms or their ecological support systems. 

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