HS Code 28.09 – Diphosphorus pentaoxide; phosphoric acid; polyphosphoric acids, whether or not chemically defined

HS code 2809 is a 4-digit heading in the Harmonized System that covers: Diphosphorus pentaoxide; phosphoric acid; polyphosphoric acids, whether or not chemically defined. Heading 2809 covers Diphosphorus pentaoxide, phosphoric acid, and polyphosphoric acids, whether or not chemically defined, representing a crucial group of phosphorus-based inorganic chemicals. Diphosphorus pentaoxide (P2O5), also known as phosphorus pentoxide, is a powerful dehydrating agent and a precursor to phosphoric acid, vital in organic synthesis and as a desiccant. Phosphoric acid (H3PO4), particularly orthophosphoric acid, is one of the most important inorganic acids, with widespread applications in fertilizers, food and beverage additives (as an acidulant), detergents, metal treatment, and pharmaceuticals. Polyphosphoric acids are oligomers of phosphoric acid, characterized by P-O-P linkages, and are used as dehydrating agents, catalysts, and in the production of specialty phosphates. The scope of this heading includes various grades and concentrations of these acids. Accurate classification under 2809 is essential for trade compliance, as it impacts tariff rates, food safety regulations (for food-grade phosphoric acid), and environmental controls related to phosphorus compounds. Historically, phosphorus compounds have been central to agriculture since the development of superphosphate fertilizers in the 19th century. These chemicals fall under Chapter 28, which broadly covers inorganic chemicals, distinguishing them from organic phosphates or formulated products. Understanding the specific form and application is critical for correct classification and navigating the complex regulatory landscape.

Orthophosphoric acid (technical grade), food-grade phosphoric acid, wet-process phosphoric acid, furnace-grade phosphoric acid, polyphosphoric acid (PPA), diphosphorus pentaoxide (phosphorus pentoxide), superphosphoric acid, dilute phosphoric acid, concentrated phosphoric acid, phosphoric acid for fertilizer production, phosphoric acid for beverage industry, phosphoric acid for rust removal, phosphoric acid for dental cements, phosphoric acid for fuel cells, phosphoric acid for water treatment, polyphosphoric acid for asphalt modification, polyphosphoric acid for chemical synthesis, diphosphorus pentaoxide for desiccation, diphosphorus pentaoxide for organic synthesis, chemically pure phosphoric acid, reagent-grade phosphoric acid, industrial-grade phosphoric acid, phosphoric acid for flame retardants.

Common misclassification errors for HS 2809 often involve confusing phosphoric acid with its salts or derivatives. For instance, classifying sodium phosphates (HS 2835) or calcium phosphates (HS 2835) under 2809, when this heading is specifically for the acid and its anhydride. Another mistake is classifying formulated products containing phosphoric acid, such as certain rust removers or industrial detergents, under 2809 instead of their more specific functional headings (e.g., HS 3402 for detergents or HS 3824 for other chemical products). Similarly, misclassifying phosphorus fertilizers (HS 3103) as pure phosphoric acid can lead to incorrect duties and regulatory non-compliance.

In 2025, the top exporters of HS code 2809 in UN Comtrade data were Morocco ($3.6B, 46% of world exports), China ($923M) and Jordan (about $830M). World exports came to about $7.7B, 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 2809 in UN Comtrade data were India ($2.5B, 40% of world imports), Pakistan ($485M) and the United States ($338M). World imports came to about $6.3B, 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 2809 is a 4-digit heading under Chapter 28 of the Harmonized System. The first 2 digits (28) identify the chapter, and digits 3-4 (09) specify the heading. This code contains multiple 6-digit subheadings for precise product classification.