Sulfonitric acid is a mixture of nitric and sulfuric acids used primarily as a nitrating agent in organic synthesis. Despite being a mixture, it is explicitly named in heading 2808 alongside nitric acid and classified under subheading 280800. A pure nitric acid solution of any concentration also falls here, not under the sulfuric acid heading.

Nitric acid above certain concentrations may be subject to Commerce Department export control review under the Export Administration Regulations (EAR) due to its dual-use potential in explosives and chemical weapons precursor applications. Importers should verify whether their specific concentration and end-use trigger any licensing or reporting obligations.