Investigation of the cause of contact dermatitis due to heavy metal in a metal spray process in a film-condenser factory]

To investigate causes of contact dermatitis in the metal spray process in a film-condenser factory, we developed a questionnaire survey for workers exposed to metal dust, analyzed the metal dust, and conducted patch tests with the metal dust and its constituents. In the questionnaire survey, we identified 12 workers (12/26, 46.2%) who had had dermatitis. The main symptoms were itching, itchy red skin and itchy papules. Analysis of the metal dust showed that there was no copper oxide, but nickel, not contained in the materials of the metal spray, was detected. One worker with dermatitis had a positive reaction to 2.5% nickel sulphate. Some of the workers showed primary irritant reactions to 5% copper sulphate. As a result, we considered that these cases of dermatitis involved irritant contact dermatitis due to copper and/or allergic contact dermatitis due to nickel. To prevent dermatitis, we recommended improvement in ventilation, reducing the room temperature to reduce sweating, and to educate workers on the importance of frequent hand washing. Thereafter, the incidence of dermatitis decreased, and there were no cases requiring medication.