[The evaluation of occupational exposure to carcinogenic substances: limit values and risk assessments]

Considering that nowadays there is no unanimity about the possibility of adopting environmental and/or biological limit values in occupational exposure to carcinogens, some aspects are discussed about the mechanism of action of carcinogens, their metabolism and problems deriving from the possible multiple exposures, interactions and speciation of the different compounds. After the analysis of the results obtained by means of two different approaches by the American Conference of Governmental Industrial Hygienist and the Environmental Protection Agency of the United States, the authors examine some aspects of the qualitative and as far as possible quantitative comparison for the 16 substances included in both lists and they discuss how the mathematical models are used in the process of carcinogenic risk evaluation. Finally, it is considered the possible application even in occupational carcinogenesis of a model such as the one of the EPA.