[Concerning the crisis of the West German politics of limit values in the 1970s: the transformation of cancer at the workplace from a toxicological into a socioeconomic problem].

The paper tackles the changes that occurred in the political culture and the episteme of risk in the Federal Republic of Germany in the 1970s. The objects of observation are limit values for hazardous industrial materials, especially for carcinogens. At the forefront of the production of such values in Germany was the German Research Society's Senate Commission for the Examination of Hazardous Industrial Materials. Limit values bring economy, politics, and science together and they mediate different interests. This makes limit values an ideal object of study to bring together changes in different parts of society. In 1972, a new category of limit values for carcinogenic substances is introduced, the so called "Technische Richtkonzentration" (TRK). This category of values does not assume that complete safety can be reached, as do limit values for hazardous industrial materials, so called "Maximale Arbeitsplatzkonzentrationen" (MAK). This means an important rupture in toxicological thinking. Until the 1970s, Paracelsus' dictum about dosage and poison still served as starting point for toxicologists. The innovation of TRK marks an important rupture in the episteme of regulating dangerous matters. Whereas until the 1970s there existed, at least as an ideal, the myth of "no risk" or "zero tolerance" even in the case of carcinogens, since the beginning of the 1970s, certainty is no more guaranteed by epistemically, but by socially robust knowledge. This also means the return of the risk society at the beginning of the 1970s, whereby cancer at the workplace becomes--in the view of the regulatory bodies--out of a medical problem a socioeconomic illness. The paper argues that these changes are connected to a general feeling of disorientation.