In a preliminary phase of a broad research project on cancer among workers in a rubber footwear plant in Moscow, exposure to several known or potential carcinogens was assessed. There were high dust contents bearing both toxic substances and carcinogens. The highest concentrations of benzo[a]pyrene (500-14,400 micrograms) were found on the soot used as a filler, and the maximum N-dimethylnitrosamine (DMNA) level was measured in thiram (150-23,868 micrograms.kg-1). Air samples from the vulcanization process and the pressing of rubber goods showed BaP levels of up to 1.43 micrograms.m-3. In the work area where polyvinyl chloride was used, the mean vinyl chloride concentration was 0.21 (SE 0.06) mg.m-3. The mean value of the acrylonitrile concentrations in the workroom area was 0.19 (SE 0.07) mg.m-3. Very high levels of DMNA and N-diethylnitrosamine were measured in the preparatory shop in the winter.