Regulatory Scene for Selected Diisocyanates

Abstract

There is a multitude of governmental activities with regard to isocyanates and diisocyanates in general. For example, the U.S. Environmental Protection Agency (EPA), under the Toxic Control Substance Administration (TSCA), has both a testing requirement and a risk management process underway on the two major isocyanates, toluene diisocyanate (TDI) and methylene diisocyanate (MDI). Recently, the U.S. National Toxicology Program (1989) listed TDI as a substance which may reasonably be anticipated to be carcinogenic leading to the listing under Proposition 65 in California. Both TDI and MDI are listed by the EPA under SARA 313 requiring annual reports on emissions. In addition, there is an EPA health effects data call-up in place on 43 separate isocyanates and diisocyanates. The listing of TDI by the International Agency for Research on Cancer (IARC) as a 2(b) carcinogen and the incorporation of both TDI and MDI in the “Seveso” list has taken place. These activities are a result of concerns regarding: 1) toxicological data published over the last few years, 2) increased public and governmental chemical awareness and phobias, and 3) finally, in part due to the Bhopal catastrophe involving methyl isocyanate. Activities to put perspective on the chemical class, particularly with regard to TDI and MDI, will be discussed.