Lack of mutagenic activity of 1,6-hexamethylene diisocyanate.

1,6-Hexamethylene diisocyanate (HDI) is an aliphatic diisocyanate used in the 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 assay, and in the mouse micronucleus test, using vapor-phase exposures. Although indicators of toxicity were observed in each test, HDI did not induce mutagenic or clastogenic effects in any of the three assays.