The German Ausschuss für Gefahrstoffe (AGS: Committee for hazardous substances) released a guidance document on how to derive quantitative exposure-risk relationship data for occupational carcinogens. The methodology uses excess risk data for the quantification of risk. Recently this method was challenged by Morfeld in this journal (Arbeitsmed Sozialmed Umweltmed 2010; 45: 480—484). The use of the excess risk of dying was judged to be based on a fundamental misconception and to provide meaningless values. Instead the derivation of an exposure-risk relationship on the basis of calculated “years of life lost” (YLL) by premature death from cancer was proposed. The present position paper is a response to the critical comments by Morfeld and it concludes: 1) In most cases animal tumour data from close-to-lifetime studies are used for the quantification of an excess risk. For these cases there is no dissent about excess risk being a suitable measure. 2) In cases where morbidity data are inadequate, epidemiological mortality data can provide a legitimate point of departure for excess risk calculations and without serious error, provided excess mortality risk is not interpreted as additional deaths and provided adequate interpretation of these data is ensured. 3) A shift from excess risk to YLL represents a shift in focus away from disease to mortality, which is in contrast with the intentions of the AGS. 4) Currently, the risk concept of the AGS aims to prevent all cancer-related diseases caused by occupational exposures with the same high probability. Introducing YLL would shift the focus from preventing occupational cancers in general to the loss of life expectancy with respect to the localization and type of cancer, leading to different risk reduction priorities. This would put in question the fundamental objective of health and safety measures at the workplace which is to prevent disease in the employees. 5) The YLL is not yet applicable in the area of occupational safety and health, because, inter alia, no societal or political consensus on YLL-based acceptable or tolerable risks exists. 6) To our knowledge, YLL is not used anywhere in the world to establish occupational exposure limit values for carcinogens. The YLL concept could conceivably provide additional information useful for describing potential consequences of occupational exposure to carcinogens, but is no suitable substitute for the current AGS approach which uses the calculated excess risk as a measure for risk reduction and safety measures for workers.
