Under the Food Quality Protection Act (FQPA) of 1996, U.S. EPA is required to consider the cumulative toxic effects from all non-occupational exposures to pesticides and other substances that have a common mechanism of toxicity. The task of identifying and determining which pesticides or chemicals should be included in a cumulative risk assessment involves a very complex process. The problems and issues that these FQPA requirements have caused or will cause are well reflected in the draft guidance documents prepared recently for aggregate exposure (U.S. EPA, 1999a) and cumulative risk assessment (U.S. EPA, 1999b).

The Delaney amendment to the Food, Drug, and Cosmetic Act states that food additives that cause cancer in humans or animals at any level shall be prohibited from such use. It was partly in response to this Delaney clause that U.S. FDA has attempted to use the excessive cancer risk of 1 in 1,000,000 as the benchmark for considering the extrapolated risk dose of a food-packaging material to be de minimus (insignificant).

U.S. OSHA’s previous standard policy, on the other hand, was to try to reduce the (typically air) levels of carcinogenic agents in the workplace as far as technologically feasible. Yet shortly on OSHA’s 10th birthday, the U.S. Supreme Court overturned its benzene standard on grounds that the agency had failed to associate a significant risk of harm to the chemical’s prevailing concentrations in the workplace (Benzene Decision, 1980).