Allergic contact dermatitis in two machinists.

Two machinists were seen whose chronic hand dermatitis was explained by allergic sensitivity to a biocide, Tris Nitro (2-[hydroxymethyl]-2-nitro-1,3-propanediol), which was added to their metalworking fluids (cutting oils) to prevent rancidity. The cause of the men's difficulty was first suspected when they had positive patch test reactions to a related biocide, Bronopol (2-bromo-2-nitropropane-1,3-diol), which we added to our standard screening tray because of its presence in more than 500 cosmetic formulations. The detective skills of the patients uncovered the chemical, Tris Nitro, related to Bronopol in their work environment. Most cases of dermatitis seen in machinists are irritant in origin. As we achieve better cooperation from the metalworking fluid industry, perhaps an increasing number of allergens will be identified. When this occurs, a cooperative manufacturer can be invaluable in directing a machinist to a replacement--a well-preserved cutting fluid free of the allergen.