Nitrosylsulfuric Acid (HNSO5) from Mexico
Nitrosylsulfuric acid, also known as chamber acid or sulfonitric acid, is a chemically defined inorganic compound with the formula HNO2SO4 or [NO]+[HSO4]-. It falls under HTS 2808.00.00.20 as a sulfonitric acid, a mixed acid containing both nitric and sulfuric acid functionalities, classified in Chapter 28 for inorganic acids.
Duty Rate — Mexico → United States
10%
Rate breakdown
9903.03.0110%Except for products described in headings 9903.03.02–9903.03.11, articles the product of any country, as provided for in subdivision (aa) of U.S. note 2 to this subchapter
Import Tips
• Classify strictly as sulfonitric acids per Chapter 28 notes; provide chemical analysis certificates confirming composition to avoid reclassification
• Comply with DOT hazardous material shipping requirements (UN 1791, corrosive liquid); include Safety Data Sheets (SDS) and proper labeling
• Verify importer security filing (ISF) for chemicals; common pitfall is incorrect storage class leading to inspection delays