Recommendations for the categorization of germ cell mutagens

Germ cell mutagens are currently classified into three categories in the Ge rman List of MAK and BAT Values. These categories have been revised and ext ended by analogy with the new categories for carcinogenic chemicals. Germ c ell mutagens produce heritable gene mutations, and heritable structural and numerical chromosome aberrations in germ cells. The original categories 1 and 2 for germ cell mutagens remain unchanged. Two new categories 3A and 3B are proposed for chemicals suspected to be germ cell mutagens. A new categ ory 5 is proposed for germ cell mutagens with low potency that contribute n egligibly to human genetic risk provided the MAK value is observed.