HS Code 28.32 – Sulphites; thiosulphates

HS code 2832 is a 4-digit heading in the Harmonized System that covers: Sulphites; thiosulphates. HS Code 2832 covers sulphites and thiosulphates, a category of inorganic chemicals with diverse applications stemming from their reducing and complexing properties. Sulphites, such as sodium sulphite and potassium metabisulphite, are widely employed as preservatives in the food and beverage industry to prevent oxidation and microbial growth, particularly in wines, beers, and dried fruits. They also serve as bleaching agents in the textile and paper industries, and as oxygen scavengers in water treatment. Thiosulphates, notably sodium thiosulphate, are renowned for their role as 'hypo' in traditional photographic processing, acting as a fixing agent to dissolve undeveloped silver halides. Beyond photography, they are used in water dechlorination, as an antidote for cyanide poisoning, and in analytical chemistry. This heading encompasses the chemically defined salts of sulphurous acid (for sulphites) and thiosulphuric acid (for thiosulphates). Accurate classification under 2832 is vital for ensuring correct customs duties, adhering to food safety regulations (for food-grade products), and complying with environmental standards for industrial discharge. These compounds represent a significant segment of the global specialty chemical market, with their applications deeply embedded in everyday products and industrial processes. As part of Chapter 28, this classification clearly distinguishes these specific sulfur-oxygen compounds from other inorganic salts based on their unique chemical structures and functionalities.

Sodium sulphite, Sodium bisulphite, Sodium metabisulphite, Potassium metabisulphite, Calcium sulphite, Ammonium sulphite, Magnesium sulphite, Sodium thiosulphate, Ammonium thiosulphate, Barium thiosulphate, Potassium thiosulphate, Lithium sulphite, Zinc sulphite, Ferrous sulphite, Manganous sulphite, Photographic sodium thiosulphate, Anhydrous sodium sulphite, Food grade sodium metabisulphite

Misclassifying sulphites and thiosulphates (2832) with dithionites (2831) or sulphates (2833) is a common error. For instance, sodium sulphite might be confused with sodium dithionite due to similar names, but their chemical structures (SO3(2-) vs. S2O4(2-)) and primary uses (preservative vs. strong reducing agent for dyeing) are distinct. Similarly, sodium thiosulphate should not be confused with sodium sulphate (2833), as thiosulphates contain an extra sulfur atom in a different oxidation state. Traders must focus on the precise chemical nomenclature and the specific anion present. Incorrect classification can lead to penalties, customs delays, especially for food-grade products requiring specific certifications, and misapplication of environmental regulations.

In 2025, the top exporters of HS code 2832 in UN Comtrade data were China ($136M, 30% of world exports), the United States ($52M) and Thailand ($44M). World exports came to about $451M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

In 2025, the top importers of HS code 2832 in UN Comtrade data were the United States ($43M, 7.1% of world imports), France ($41M) and Mexico ($36M). World imports came to about $601M, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Countries that did not report 2025 data are estimated from partner records, which can understate them.

HS code 2832 is a 4-digit heading under Chapter 28 of the Harmonized System. The first 2 digits (28) identify the chapter, and digits 3-4 (32) specify the heading. This code contains multiple 6-digit subheadings for precise product classification.