Nitrosylsulfuric Acid (HNSO5) from Canada
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 — Canada → United States
10%
Rate breakdown
9903.05.2910%Except for products described in headings 9903.05.85–9903.05.93, articles the product of Canada, as provided for in U.S. note 52 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