An analysis of criteria for biological limit values developed in Germany and in the United States.

The biological tolerance values established by the German Research Foundation and the biological exposure indices developed by the American Conference of Governmental Hygienists represent two extensive lists of occupational exposure guidelines for use in biological monitoring. Although there is substantial agreement between the two organizations on most points, there are several important differences in the approaches taken in setting of the guideline values. Analysis of these distinctions serves to focus attention on the current issues impeding international agreement over occupational exposure guidelines. Among these issues are (1) the specification of the biological monitoring guidelines as ceiling or average values; (2) whether carcinogenic substances should be treated differently from agents with other toxic outcomes; (3) the method of accounting for variability among individual workers; and (4) the extent to which these guidelines should be extended to include genetic markers, indicators of susceptibility, or indicators of early biological response.