Introduction: This paper describes the available exposure information for carcinogens in Great Britain and discusses some of the issues involved in using such data to inform an assessment of the attributable occupational cancer burden.
Methods: Carcinogenic agents or occupations/industries such as hairdressers were identified from the list of International Agency for Research on Cancer groups 1 and 2a evaluations and estimates of exposure prevalence for 1990-1993 were obtained for a subset of these agents/circumstances from the CARcinogen EXposure (CAREX) database, compiled as part of the Europe Against Cancer programme. Estimated prevalence of exposure was added for some carcinogenic exposure circumstances not covered by CAREX. Information about the level of exposure to chemical agents was obtained from the Health and Safety Executive's (HSE) National Exposure Database. Other information was obtained from relevant databases such as the Central Index of Dose Information for ionizing radiation or published sources.
Results: In total, there were 64 carcinogenic agents/circumstances identified with almost seven million people exposed in Great Britain. The top 30 entries covered 99.5% of the estimated exposed population. The CAREX data were generally higher than the comparable data on the numbers of people exposed to those agents available from the HSE, although in some individual cases there was considerable over- or underestimation of the exposure prevalence when using the CAREX database. The level of exposure varied greatly between substances and between workplaces. For some agents, e.g. radon and sunlight, there are important regional differences in exposure within the country. Exposure to carcinogenic agents in Great Britain was different from that in other countries: in some cases higher and in others lower. Exposure levels in the past in Britain were mostly greater than today.
Conclusions: Generalizing risk estimates from epidemiological studies in different countries or the past to estimate the fraction of cancers attributable to work must be done with care, particularly in the case of population-based case-control studies where exposure estimates are generally crude. Better estimates of the distribution of levels and the prevalence of occupational exposure to carcinogenic substances in Great Britain are needed and systems should be put in place to track this information in the future. With commitment from all stakeholders, it is possible that by 2025 exposure to known occupational chemical carcinogens could be essentially eliminated in Great Britain.