Foreward

This guidance document is designed specifically for medical personnel to provide current information about the potential
health effects from diisocyanate (1) exposure, and to provide guidance to assist with medical diagnosis and management. The discussion focuses on two widely used diisocyanate-based products: diphenylmethane diisocyanate (MDI) and toluene diisocyanate (TDI). (2) (3) (4)

Although this guidance reflects the current scientific knowledge and experience of medical researchers, industrial hygienists, manufacturers, and other knowledgeable experts, it is not intended to be a comprehensive or detailed discussion of all aspects of the subject, but rather an overview. Medical personnel and other health professionals can keep themselves informed of recent developments in this field by consulting  the current scientific literature, as well as manufacturers’ and suppliers’ product safety literature (e.g., (Material) Safety Data Sheets (SDSs)).

(1) Diisocyanates are organic compounds containing two isocyanate groups (-NCO). They are used primarily in the manufacture of polyurethane systems to make foams, elastomers, coatings, adhesives and other polymeric products.

(2) TDI is manufactured predominantly as a mixed ratio, 80:20, of the 2,4-TDI and 2,6-TDI isomers (CAS# 26471-62-5).

(3) MDI is the usual abbreviation for monomeric methylene diphenyl diisocyanate, (CAS# 101-68-8). The “polymeric” forms of MDI,  which typically consist of 30-70 percent monomeric diphenylmethane diisocyanate and the balance in higher molecular weight fractions (CAS # 5873-54-1) may at times be generically referred to as MDI.

(4) For further information about the handling of TDI and MDI, consult the following bulletins published by the Center for the Polyurethanes Industry of the American Chemistry Council: Guidance for Working with MDI and Polymeric MDI: Things You Should Know (AX-205) and Guidance for Working with TDI: Things You Should Know (AX-202) available at www.polyurethane.org.