Laserfiche WebLink
r <br /> Human Health Risk Assessment <br /> Former Mobil Oil Bulk Plant 04-343 <br /> 500 East Grant Line Road <br /> Tracy, California <br /> The major motivation for conducting a health risk assessment comes from federal legislation. <br />' Since 1972 federal health and safety statutes have accepted a general safety standard of <br />' "unreasonable risk." However, these statutes do not contain a definition of what constitutes <br /> unreasonable or reasonable risk. An important component of risk management is to differentiate <br /> between significant risks that may warrant attention, and trivial risks that are relatively <br />' insignificant. The legal doctrine de minimis non curat lex (de minimise refers to risks that are <br /> too small to either be of social concern or to justify the use of resou;•,es to control. <br /> tIn response, regulatory agencies frequently adopt a de minimis r.;k criteria of between <br /> 1 in 100,000 (e.g., California Proposition 65) and 1 in 1,000,000 when fairly large populations <br /> may be exposed to a potential carcinogen. The incremental risk of 1 in 1,000,000 actually <br /> represents a risk range of between 0 and 1 in 1,000,000. Therefore, it is not expected that for <br />' every one million exposed individuals, one additional person would develop cancer in their <br /> lifetime. <br />' 6.3 CALCULATION OF CARCINOGENIC RISKS <br /> i <br /> Estimated human exposure to potential carcinogens are reported as a Lifetime Average Daily <br /> Dose (LADD). The LADD is an upper-bound estimate of the daily dose, averaged over a <br />' lifetime of 75 years, received by a receptor. The Cancer Slope Factor is the quantitative <br /> relationship between the dose of a chemical and the probability of induci-ig a carcinogenic effect. <br />' The LADD is multiplied by the chemical-specific Cancer Slope Factor to estimate the <br /> incremental cancer risk via the following equation. <br /> 1 <br /> Risk = LADD x Cancer Slope Factor <br /> 1 <br /> The calculated incremental risk is compared to acceptable risk levels an order to determine its <br />' significance. <br /> 1 <br /> 30-0136-11 <br /> �' 6-2 <br />