Background. Fiveworkers from a plantmanufacturing concrete wall panels and beams were referred to our department because of suspected occupational dermatitis. When patch tested, 3 workers reacted to potassium dichromate. Four workers reacted to ethylenediamine dihydrochloride, without any obvious exposure. Owing to the high proportion of workers with recent-onset skin disease, an investigation of all workers at the plant was initiated. Objectives. To investigate the prevalence of occupational dermatitis and contact allergy in the workers at the plant. Methods. All 24 workers at the plant underwent a clinical investigation and were patch tested. Results. Four cases of allergic occupational contact dermatitis and 3 cases of irritant occupational contact dermatitis were diagnosed. Contact allergy to potassium dichromate was found in 4 workers. All 4 also reacted to ethylenediamine dihydrochloride and/or amines that were present as additives in the cement. Conclusions. Chromate contact allergy can still be found in concrete workers, despite the legislation regulating the amount of hexavalent chromium (chromate) in cement. Occupational contact allergy to amines can be found in workers exposed to cement and concrete, so amines should be tested in these workers.