The dermatological effects of cutting oils were investigated in a tool manufacturing company (SIC-3546). An environmental evaluation was performed by a NIOSH investigation team. Samples of soap and cutting oils were obtained and analyzed for pH and acid milliequivalent needed for neutralization (the amount of acid required to reduce the pH to 7). Medical evaluations were performed on the skin of 41 workers. Of the workers, 11 had dermatitis and 10 reported similar problems in the past. Oil folliculitis and primary irritant dermatitis were found to be caused by two of the cutting oils used. The pH of the soap used was 9.4, with an acid milliequivalent of 20.4. Of the two offending cutting oil compounds, the pH of compound 3 was 8.7, and 8.6 in diluted form with 1.1 and 3.2 acid milliequivalents needed for neutralization, respectively. Compound 7 cutting oil was neutral. The author concludes that gloves, aprons, and protective clothing should be worn, surfaces should be kept free of oil, and waterless hand cleaners should be used. Irritating oils should be replaced with less toxic ones, and medical treatment should be sought if dermatitis occurs.