Occupational dermatitis from isothiazolinones in the nylon production

Kathon is a biocide consisting of a mixture of two isothiazolinone derivatives (5-chloro-2-methyl-4-isothiazolin-3-one and 2-methyl-4-isothiazolin-3-one) in an approximate ratio of 3:1, respectively, and with MgCl2 and Mg(NO3)2 present as stabilizers. The isothiazolinones are marketed under several brand names, and the concentration of the active ingredient varies according to their intended application. At a concentration of 3-15 ppm it shows activity against a wide spectrum of fungi, gram-positive and gram-negative bacteria. Contact allergy to it has been caused by cosmetics and also by products used in the pottery and various other industries. Recently we had the opportunity to observe 6 cases of occupational allergic contact dermatitis from an isothiazolinone mixture named Grotan TK 2 in a large textile industry producing nylon. An oil emulsion containing isothiazolinones is used in the spinning phase of the work cycle to prevent bacterial contamination that would damage yarn quality; furthermore, it helps to decrease the electrostatic charge that is produced by high speed at which the yarn moves and also to decrease the breakage possibility.