Industrial contact dermatitis. Effect of the riot control agent ortho-chlorobenzylidene malononitrile

Twenty-five of twenty-eight workers in a chemical plant manufacturing ortho-chlorobenzylidene malononitrile (CS) gave a history of dermatitis involving the arms and neck. Two of twenty-five of the workers showed positive patch test reactions when tested to a 1:1,000 dilution of CS in olive oil. The study reveals that in the industrial setting, a significant sensitizing potential exists, but irritancy was the major factor in the production and perpetuation of the dermatitis. An awareness of the possible cutaneous responses to this chemical is advisable in lieu of its use by the military in Vietnam and by civilian authorities in the United States, as well as its adoption as the active ingredient in a line of personal protective devices.