Certain nitrate compounds — particularly ammonium nitrate — are subject to ATF and DHS oversight as potential explosives precursors. Importers should verify whether their specific compound and concentration trigger any reporting, licensing, or end-use certification requirements under applicable federal regulations.

Nitrites (NO₂⁻ anion) classify under 283410, while nitrates (NO₃⁻ anion) fall under 283421 or 283429 depending on the cation. The chemical distinction is straightforward but matters for duty purposes because each subheading carries its own tariff rate and may be subject to different trade-remedy measures.