One hundred and fifty-two workers from ten polyvinyl chloride (PVC) plastic factories were studied for lead exposure. Blood lead (Pb-B) concentration was measured for all the workers, urinary delta-aminolevulinic acid (ala) for 130 workers, erythrocyte alpha-aminolevulinic acid dehydratase (ala-d) activity for 59 workers, and blood hemoglobin concentration or 93 workers. The median Pb-B for all the workers was 37 mug/100 ml, and the highest median found for one factory was 63 mug/100 ml. The highest single Pb-B value found was 126 mug/100 ml. The jobs with the heaviest lead exposure were those of mixing and weighing lead stearate powder. It is assumed that replacing the powder with a granule form of lead stearate will diminish the hazard of lead exposure in the future. Urinary ALA concentrations and erythrocyte ALA-D activities corresponded well with the Pb-B concentration, but the hemoglobin values did not show any relation to lead exposure. It is concluded that in the PVC plastic industry of Finland the risk of exposure to lead is high and regular health examinations should be performed.

Key terms blood; Finland; lead; lead exposure; occupational lead exposure; plastic; plastic industry; polyvinyl chloride; polyvinyl chloride plastic industry