This report contains the results of a study undertaken by Associated Nuclear Services (ANS) for the Directorate General of Employment, Social Affairs and Education of the Commission of the European Communities (CEC). This study was entitled Dynamics of Selected Toxic Materials in Man . vii 2 Summary This report presents results from the second phase of a study on the metabolism of selected actual and potential human carcin- ogens. In the first phase of this work a comprehensive review of literature relating to the metabolism of these materials was under- taken and pharmacokinetic models were proposed to represent that meta- bolism. It was suggested that these models, and the reviews on which they were based, would provide information relevant to the development of monitoring programmes and in the interpretation of dose-response data. In the second phase of the study, attention has been concen- trated on the implementation of the models proposed for the various substances reviewed, i.e. arsenic, beryllium, cadmium, lead, nickel, chromium, asbestos, benzene, vinyl chloride monomer, benzidine and its congeners, carbon tetrachloride and methyl iodide. However, this programme has been supplemented by an on-going review of the relevant literature on these substances and a detailed analysis of the applica- bili ty of the pharmacokinetic models used for the organs of intake, i.e. the lung and gastrointestinal tract.