Abstract Summary
In the twentieth century, the proliferation of synthetic chemicals prompted US and European governments to introduce regulatory regimes for the control of chemicals. It was especially consumers’ concerns about artificial food additives and synthetic pesticides that inspired environmentalism and prompted a wave of environmental regulations in the postwar decades. However, aflatoxin, a mold-produced carcinogen, has challenged scientists’ and regulators’ notions of toxic substances and control ever since its discovery in 1960. This paper describes how scientists of the US Food and Drug Administration (FDA) and the Scientific Committee on Food of the European Commission studied this “naturally-occurring” toxic substance and developed regulatory strategies from 1960 to the early 1990s. The agencies quickly devised ways to classify and regulate aflatoxin within the legal frameworks for synthetic contaminants. In the early 1980s, Bruce Ames challenged the whole regulatory framework by arguing that the health effects of synthetic chemicals were insignificant compared to the ones of unavoidable natural toxins, such as aflatoxin. In the meantime, agricultural scientists had shown that the formation of aflatoxin depended as much on human agricultural practices as on environmental conditions. This paper analyzes when, how, and why Ames, Philippe Shubik, René Truhaut, and other key figures evoked aflatoxin’s naturalness. The paper argues that evoking the difference between synthetic and natural chemicals served the justification and legitimacy of regulations at specific points, rather than reflecting different ontologies or research practices in the study of toxic substances