D regulations promulgated in the absence of evidence of carcinogenicity permitted use of the four pesticides as food additives. The four pesticide chemicals which were benomyl, mancozeb, phosmet and trifluralin, were all the subject of regulations issued by D permitting their use. Eventually D found these pesticides to be carcinogens. D refused to revoke the earlier regulations, reasoning that, although the chemicals posed a measurable risk of causing cancer, that risk was 'de minimis.' The Delaney Clause of the Federal Food, Drug, and Cosmetic Act (FFDCA) prohibited the use of such substances as food additives. A food 'additive' is defined broadly as 'any substance the intended use of which results or may reasonably be expected to result . . . in its becoming a component . . . of any food.' A food additive is considered unsafe unless there is a specific exemption for the substance or a regulation prescribing the conditions under which it may be used safely. The Delaney clause prescribes that additives found to induce cancer can never be deemed 'safe' for purposes of the FFDCA. Ps petitioned to revoke these D regulations for these four additives. D refused. D claimed the cancer risk was de minimis. Ps filed objections to that response, and D published its final order denying the petition to revoke the food additive regulations. Ps appealed. D claimed reliance on a scientific study.