Cement dermatitis, an example of occupational contact dermatitis from limestone is described. There is an interplay of factors leading to primary irritant contact dermatitis and also to allergic eczematous contact dermatitis caused by trace metals, particularly chromium. Thirty-one occupations with potential cement exposure are listed. Construction workers are exposed to a variety of irritants and sensitizers and generally do not have adequate washing facilities. The manufacture of cement, patterns of dermatitis, and nature of dermatitis are described. To determine the presence of delayed hypersensitivity, patch tests should be performed with the trace metals found in cement. Protective clothing and a no-touch technique will be of greatest value in preventing future attacks in affected workers.