Introduction Strategies for reducing occupational exposure to carcinogens and allocating available resources effectively and efficiently require high quality information based on scientific evidence. With this purpose, the Occupational Health and Safety Institute of the Government of Catalonia developed the map of exposure to carcinogens in the workplace in Catalonia (CAREX-CAT) based on the methodology of the CAREX system.

Methodology Cross-sectional study. CAREX-CAT includes the agents related to occupational exposures classified by the IARC into groups 1/2 A and a selection of agents classified into group 2 B, as well as those chemicals considered to be carcinogens by the European legislation. It is based on economic activity, reaching a 3-digit level of the Catalonian Industrial Classification. A multistage sampling design was used. Sample size was 98,000 workers from 1,600 companies in Catalonia. Information was collected between 2013–2015 through direct observation of work processes by hygienists using a standardised questionnaire. For some non-manufacturing sectors, information was collected from a literature review (2-digit level). The prevalence of exposure by agent and economic sector, and the proportion of multi-exposed workers were estimated.

Results CAREX-CAT estimated the number of workers exposed to 76 carcinogens. The most common exposures were solar ultraviolet radiation (10.5%), night shift work (7.1%) and diesel engine exhaust (4.1%). After excluding exposure to solar radiation, shift work and radon, at least one third of the economic activities analysed (3-digit level) had more than 10% of their workers continuously exposed to carcinogens, and one third of activities had over 50% of their workers multi-exposed.

Conclusions A substantial proportion of Catalan workers are exposed to carcinogens at work. The information provided by CAREX-CAT is essential for the labour administration and other occupational health and safety agents to establish priorities for the primary prevention of occupational cancer and to design and implement interventions based on scientific knowledge.