HEALTH SURVEY OF FORMER WORKERS IN A NORWEGIAN COKE PLANT - PART 1 - ESTIMATION OF HISTORICAL EXPOSURES

Objective-To estimate historical exposure levels at a coke plant for a ll agents considered to be of importance for epidemiological studies o f mortality and cancer incidence. Methods-Time weighted average exposu re (8 h TWA) was estimated based on personal measurements for polycycl ic aromatic hydrocarbons (PAHs) and carbonaceous particulates. Exposur e to quartz was estimated relative to the concentration of carbonaceou s particulates. These estimates were adjusted for the use of airstream helmets. Exposure to other agents were estimated qualitatively (asbes tos, benzene, and arsenic) or semiquantitatively (carbon monoxide (CO) and heat) based on measurements and other indicators of exposure. Res ults-Exposure to PAHs was highest for those who worked at the top of t he ovens (300 mu g/m(3)) in the period from 1970-6. The estimated PAH exposure was reduced to an average of 65 mu g/m(3) after the introduct ion of exposure control measures in 1976. The estimates for carbonaceo us particulates ranged from 1 to 16 mg/m(3), with the highest exposure for workers at the top of the ovens and at the coke screening station . Conclusions-The exposure of greatest concern in this study is to PAH s, but exposures to carbonaceous particulates and CO may also be of im portance. The major limitations of this study are the lack of personal measurements before 1975 and the total lack of measurements for some of the exposed categories of workers. Despite these Limitations, we th ink that this assessment reflects the actual exposures for most of the former employees. The assessment thus provides a reasonable tool for the subsequent epidemiological study and for future epidemiological fo llow up studies at the coke plant.