Occupational allergic contact dermatitis from 2,3-epoxypropyl trimethyl ammonium chloride (EPTMAC) and Kathon LX in a starch modification factory.

2,3-epoxypropyl trimethyl ammonium chloride (EPTMAC) is used in the production of cationic starch (CS) for the paper industry. It has been shown to be a sensitizer in guinea pigs, but cases of human sensitization are few. 4 workers were previously sensitized to the substance in a Finnish plant. This report describes 3 process men from another plant examined because of recurring dermatitis. 18 workers were involved in production, and had free access to all work sites. 3 process men, whose work involved drying the CS, had dermatitis, although they had only occasional contact with the cationizing chemical. 2 were already verified to be allergic to EPTMAC and had had variable dermatitis for 8-12 years. One had had dermatitis on his face for 1 year. Patch testing with a dilution series (1%, 0.5%, 0.2%, 0.1% pet.) confirmed their allergy to the cationizing chemical containing EPTMAC, but tests with CS were negative. In addition, 2 had contact allergy to Cl+ Me-isothiazolinone from contact with Kathon LX used as a slimicide in the process. In long-standing (years) recurrent dermatitis, re-examination of patients with verified exposure history and skin test is necessary. In line with our previous study, sampling the process materials, maintenance work and contamination of work sites and gloves caused sensitization. The results also confirm that EPTMAC is a strong human contact sensitizer. 0.2%-0.5% pure EPTMAC in pet. seems to be the optimal patch test concentration.