Toluene diisocyanate exists in two isomeric forms which have similar properties and effects. Toluene diisocyanate is produced commercially as an 80:20 mixture of the two isomers. At room temperature, the mixture is a clear, pale yellow liquid with a sharp, pungent odor. It should be stored under refrigeration, away from light and moisture in a tightly closed container under an inert atmosphere. Toluene diisocyanate is insoluble in water and miscible with most common organic solvents.