Expert assessment of exposure to carcinogens in Norway's offshore petroleum industry

This study presents and evaluates an expert group's assessment of exposure to carcinogens for defined job categories in Norway's offshore petroleum industry, 1970-2005, to provide exposure information for a planned cohort study on cancer. Three university and five industry experts in occupational hygiene individually assessed the likelihood of exposure to 1836 combinations of carcinogens (n=17), job categories (n=27) and time periods (n=4). In subsequent plenary discussions, the experts agreed on exposed combinations. Agreement between the individual and the panel assessments was calculated by Cohen's kappa index. Using the panel assessment as reference, sensitivity and specificity were estimated. The eight experts assessed 63% of the 1836 combinations in plenary, resulting in 265 (14%) convened exposed combinations. Chlorinated hydrocarbons, benzene and inhalation of mineral oils had the highest number of exposed job categories (n=14, 9 and 10, respectively). The job categories classified as exposed to the highest numbers of carcinogens were the mechanics (n=10), derrick workers (n=6) and process technicians (n=5). The agreement between the experts' individual assessments and the panel assessment was kappa=0.53-0.74. The sensitivity was 0.55-0.86 and specificity 0.91-0.97. For these parameters, there were no apparent differences between the university experts and the industry experts. The resulting 265 of 1836 possible exposure combinations convened as "exposed" by expert assessment is presented in this study. The experts' individual ratings highly agreed with the succeeding panel assessment. Correlation was found between years of experience of the raters and agreement with the panel. The university experts and the industry experts' assessments had no apparent differences. Further validation of the exposure assessment is suggested, such as by new sampling data or observational studies.