Vorschlage zur anderung der einstufung krebserzeugender arbeitsstoffe

Carcinogenic chemicals in the work area are currently classified into three categories in chapter III of the German List of MAK and BAT Values. This classification is based on qualitative criteria and reflects essentially the weight of evidence to judge the carcinogenic potential of the chemicals. It is proposed to retain these Categories - IlIA1, IIIA2, IIIB - as Categories 1, 2, and 3, to conform with EU regulations. On the basis of the advanced knowledge on reaction mechanism and the potency of carcinogens, it is now proposed to supplement these three categories by two additional categories. The essential feature is that exposure to these chemicals does not convey a significant risk of cancer to man, provided an exposure limit value (MAK value) is observed. It is proposed to classify chemicals known to act typically by non-genotoxic mechanisms and for which information is available that allows evaluation at low-dose exposures in Category 4. Genotoxic chemicals for which low carcinogenic potency can be expected on the basis of dose-response relationships and toxicokinetics and for which risk at low doses can be assessed could be classified into Category 5. The basis for a better differentiation of carcinogens is discussed, the new categories are defined, and possible criteria for classification are described. Examples for Category 4 (1,4-dioxane) and Category 5 (styrene) are presented. The proposed changes in classifying carcinogenic chemicals in the work area are presented for further discussion.