Formaldehyde (methanal) in its monomeric form falls under subheading 291211, while paraformaldehyde — the solid polymeric form of formaldehyde — has its own dedicated subheading 291260. The physical form and degree of polymerization determine which applies; importers should confirm the product specification before filing.

When imported for use as food flavoring, vanillin and ethylvanillin may be subject to FDA review as food additives or GRAS substances. Classification under heading 2912 does not itself trigger mandatory FDA admissibility review, but the intended end use governs whether FDA oversight applies. Consult a licensed customs broker or regulatory counsel to confirm the applicable regime.