[5] Other major producers are Covestro,[6] BASF, Dow, Huntsman, Tosoh, Kumho Mitsui Chemicals.

[9] These rigid polyurethane foams are good thermal insulators and used in nearly all freezers and refrigerators worldwide, as well as buildings.

Typical polyols used are polyethylene adipate (a polyester) and poly(tetramethylene ether) glycol (a polyether).

4,4′-MDI is also used as an industrial strength adhesive, which is available to end consumers as various high-strength bottled glue preparations.

Persons developing sensitivity to isocyanates may have dangerous systemic reactions to extremely small exposures, including respiratory failure.