Neumann H G, Vamvakas S, Thielmann H W, Gelbke H P, Filser J G, Reuter U, Greim H, Kappus H, Norpoth K H, Wardenbach P, Wichmann H E
Institute for Toxicology and Pharmacology, University of Würzburg, Germany.
Int Arch Occup Environ Health. 1998 Nov;71(8):566-74. doi: 10.1007/s004200050325.
Carcinogenic chemicals in the work area are currently classified into three categories in section III of the German List of MAK and BAT Values (list of values on maximum workplace concentrations and biological tolerance for occupational exposures). This classification is based on qualitative criteria and reflects essentially the weight of evidence available for judging the carcinogenic potential of the chemicals. It is proposed that these categories - IIIA1, IIIA2, IIIB - be 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 risk of cancer to man, provided that an appropriate exposure limit (MAK value) is observed. Chemicals known to act typically by nongenotoxic 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.
工作场所中的致癌化学物质目前在《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性值列表）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。建议将这些类别——IIIA1、IIIA2、IIIB——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了解，这三类又补充了另外两类。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癌症风险的贡献就不大。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。根据剂量反应关系和毒代动力学可预期低致癌效力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。
