Subheading 292910 covers compounds whose defining functional group is the isocyanate (–N=C=O), including monomeric and polymeric MDI and TDI. If the compound contains a different nitrogen function—such as a nitrile, hydrazone, or amine—it will fall under a different heading or, if truly residual, under 292990. The heading text and the chapter notes should be read together to confirm the principal functional group.

Isocyanates require a TSCA import certification at entry. Because they are classified as hazardous chemicals under OSHA's Hazard Communication Standard, Safety Data Sheets must accompany commercial shipments. Importers should also verify whether the specific compound or formulation triggers any EPA Significant New Use Rule (SNUR) notification obligations.