The U.S. Supreme Court’s decision on worker exposure to benzene (Benzene Decision, 1980) rules that the allowable levels of a chemical in the workplace be regulated not only on the basis of mitigation feasibility, but also with the demonstration of a significant risk from exposure to the unmitigated levels (as briefly discussed in Slide 20 of Lecture 2; see also Slide 22 of this lecture).

The Delaney clause of the Federal Food, Drug, and Cosmetic Act (FFDCA) imposes a zero tolerance for carcinogens in processed foodstuffs or as food additives. This imposition eventually has led to a compromised acceptance of the practical de minimus excess risk of 1 x 10^-6 (one in one million) or less as free of cancer risk. The Federal Insecticide, Fungicide, and Rodenticide Act, on the other hand, requires U.S. EPA to provide a balance of risk and benefit in considering the application of pesticides to raw agricultural products.

The FFDCA, later amended by the Food Quality Protection Act of 1996, mandates the consideration of aggregate and cumulative exposures in determining the allowable daily intake and the de minimus level for cancer risk. Aggregate exposure includes exposures to all pathways and sources, whereas cumulative exposure encompasses those to multiple chemicals that have a common mechanism of toxicity. Pesticides are particularly subject to aggregate and cumulative exposure consideration, in that some of them can be used in homes and are present in foodstuffs as a result of their application to agricultural crops.