Acceptable risk recommendations concerning

The U.S. Environmental Protection Agency (EPA) presently has no limits on dioxin contamination levels in soil. After studying the risks, however, the Centers for Disease Control (CDC) of the U.S. Department of Health and Human Services in Atlanta, GA, has concluded that residual soil contamination levels at or above 1 ppb of 2,3,7,8-TCDD in residential areas cannot be considered safe and represent a level of concern ( 5). Uniform contamination levels are assumed. CDC also recommends low levels for pasture lands because of food chain accumulation. However, CDC concludes that, in certain commercial areas, higher levels in soils may represent an acceptable risk to nonoccupationally exposed individuals, but that level has not been defined. 

EPA recommends three approaches (1) if the toxicity data on mixture of concern are available, the quantitative risk assessment is done directly form these preferred data (2) when toxicity data are not available for the mixture of concern, data of a sufficiently similar mixture can be used to derive quantitative risk assessment for mixture of concern and (3) if the data are not available for both mixture of concern and the similar mixture, mixture effects can be evaluated from the toxicity data of components. According to EPA, the dose-additive models reasonably predict the systemic toxicity of mixtures composed of similar (dose addition) and dissimilar (response addition) compounds. Therefore, the potential health risk of a mixture can be estimated using a hazard index (HI) derived by summation of the ratios of the actual human exposure level to estimated maximum acceptable level of each toxicant. A HI near to unity is suggestive of concern for public health. This approach will hold true for the mixtures that do not deviate from additivity and do not consider the mode of action of chemicals. Modifications of the standard HI approach are being developed to take account of the data on interactions. 

Chemical Vulnerability Assessment. Vulnerability analysis is a systematic method for estimating friendly casualties and/or consequences from enemy or terrorist chemical attacks. The end state of vulnerability analysis is the recommendation to the commander on vulnerability reduction measures and to provide the information needed to make decisions concerning the acceptable level of risk in mission accomplishment. 

In the practice of occupational safety and health in industry today, the primary concern of any responsible organization is the identification and elimination of hazards that threaten the life or health of employees, as well as those that could cause damage to facilities, property, equipment, products, and/or the environment. When such risk of hazard cannot be totally eliminated, as is often the case, it becomes a fundamental function of the safety professional to provide recommendations to control those hazards in an effort to reduce the associated risk to the lowest acceptable levels. 

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