Exposure to carcinogenic chemicals at work is again debated owing to continuous technological developments. The observed decrease in cancer mortality in North America and in Western Europe after the 1980s can be attributed to several factors including a reduction of exposure to carcinogens at work. A multicentric study was conducted in Lombardy (PPTP-Study) in order to assess the actual presence and possible exposure to chemical carcinogens, with the aim of mapping the work areas at greatest risk at present. The results showed that an integrated use of databases to map the exposed workers may provide a useful starting point to set priorities for preventive action, but it must be underlined the need of a constant updating about the evolution of the technological innovations of enterprises.