Lack of mutagenic activity of 1,6-hexamethylene diisocyanate

1,6-Hexamethylene diisocyanate (HDI) is an aliphatic diisocyanate used in t he manufacture of higher molecular weight biuret and trimer polyisocyanate resins. These resins are commonly used in polyurethane paints, resulting in potential occupational, and to a lesser extent consumer exposures. Because some isocyanates have been reported to be mutagenic, HDI was tested in the bacterial reverse mutation assay (Ames test), CHO/HGPRT gene mutation assa y, and in the mouse micronucleus test, using vapor-phase exposures. Althoug h indicators of toxicity were observed in each test, HDI did not induce mut agenic or clastogenic effects in any of the three assays.