Neumann H G, Thielmann H W, Filser J G, Gelbke H P, Greim H, Kappus H, Norpoth K H, Reuter U, Vamvakas S, Wardenbach P, Wichmann H E
Institute for Toxicology and Pharmacology, University of Würzburg, Germany.
J Cancer Res Clin Oncol. 1998;124(12):661-9. doi: 10.1007/s004320050229.
Carcinogenic chemicals in the work area were previously classified into three categories in section III of the German List of MAK and BAT values (the list of values on maximum workplace concentrations and biological tolerance for occupational exposures). This classification was based on qualitative criteria and reflected essentially the weight of evidence available for judging the carcinogenic potential of the chemicals. In the new classification scheme the former sections IIIA1, IIIA2, and IIIB are retained as categories 1, 2, and 3, to correspond with European Union regulations. On the basis of our advancing knowledge of reaction mechanisms and the potency of carcinogens, these three categories are supplemented with two additional categories. The essential feature of substances classified in the new categories is that exposure to these chemicals does not contribute significantly to the risk of cancer to man, provided that an appropriate exposure limit (MAK value) is observed. Chemicals known to act typically by non-genotoxic mechanisms, and for which information is available that allows evaluation of the effects of low-dose exposures, are classified 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 are classified in 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.
工作区域中的致癌化学物质先前在德国MAK和BAT值列表（职业接触的最大工作场所浓度和生物耐受值列表）的第三部分中分为三类。这种分类基于定性标准，基本上反映了用于判断化学物质致癌潜力的现有证据的权重。在新的分类方案中，先前的IIIA1、IIIA2和IIIB部分保留为第1、2和3类，以符合欧盟法规。基于我们对反应机制和致癌物效力的不断深入了解，这三类又增加了两类。新类别中分类物质的基本特征是，只要遵守适当的接触限值（MAK值），接触这些化学物质对人类患癌风险的贡献就不大。已知通常通过非遗传毒性机制起作用且有信息可用于评估低剂量接触影响的化学物质分类为第4类。基于剂量/反应关系和毒代动力学预期致癌效力低且可评估低剂量风险的遗传毒性化学物质分类为第5类。讨论了更好地区分致癌物的依据，定义了新类别，并描述了可能的分类标准。给出了第4类（1,4-二氧六环）和第5类（苯乙烯）的示例。
