HS 283531 Polyphosphates
Quick Answer: HS 283531 covers sodium tripolyphosphate (STPP), a widely used polyphosphate. This inorganic chemical is primarily utilized as a builder in detergents, a food additive (e.g., emulsifier, moisture retention agent), and in water treatment. Importers and exporters should note the varying duty rates: the UK applies a 4.00% ad valorem duty, the EU a 5.50% ad valorem duty, and the US a 6% ad valorem duty under the Harmonized Tariff Schedule (HTS). Significant trade considerations for the US include preferential duty treatment, with rates as low as 1.4% or Free for goods originating from countries with applicable Free Trade Agreements (FTAs) or special programs (e.g., A, AU, BH, CL, CO, D, E, IL, JO, KR, MA, OM, P, PA, PE, S, SG). Accurate classification is crucial for compliance and optimizing landed costs.
What Are the Import Duty Rates?
🇬🇧 United Kingdom
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2835310000 | 4.00 % | — | — |
🇪🇺 European Union (TARIC)
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2835310000 | 5.50 % | — | — |
🇺🇸 United States (HTSUS)
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2835310000 | 1.4% | Free (17 programs) | ["kg"] |
Special rates available under trade agreements including USMCA, KORUS, GSP.
Duty rates sourced from the USITC (US International Trade Commission) Harmonized Tariff Schedule (HTS) (accessed 2/22/2026), EU TARIC – DG TAXUD (Directorate-General for Taxation and Customs Union) (accessed 2/22/2026), and UK Trade Tariff – HMRC (His Majesty's Revenue and Customs) (accessed 2/22/2026).
Data compiled and presented by HSRates.
Which Trade Agreements Reduce Duties for HS 2835.31?
Imports of Polyphosphates may qualify for reduced or zero duty rates under free trade agreements and preferential programs. The overview below shows available preferential arrangements by jurisdiction, compiled by HSRates from official tariff and trade agreement data.
United States (HTSUS)
Free for USMCA, KORUS, GSP, and 14 other programs
European Union (TARIC)
Preferential rate data not yet available.
United Kingdom
Preferential rate data not yet available.
Preferential rates require proof of origin and may be subject to quotas or conditions. Always verify eligibility with a licensed customs broker.
Data compiled by HSRates.
Which Preferential Rates Apply to Your Origin Country?
Select an origin country to see if preferential rates apply.
Preferential rates based on available trade agreements. Actual rates may vary.
How Has Trade Volume Developed?
How to Classify This HS Code?
What products does HS 283531 cover?
This subheading covers sodium tripolyphosphate, also known as sodium triphosphate, a specific type of polyphosphate. According to the Harmonized System Nomenclature Explanatory Notes (WCO) for Heading 2835, polyphosphates are salts or esters of polyphosphoric acids. Subheading 2835.31 specifically identifies "Sodium triphosphate (sodium tripolyphosphate)" as the product within its scope. This chemical compound is widely used as a builder in detergents, a food additive (e.g., emulsifier, moisture retention agent), and in industrial applications such as water treatment. The USITC Harmonized Tariff Schedule (HTS) and EU TARIC both align with this specific designation, ensuring consistent global classification for this particular sodium salt.
What falls outside HS 283531?
The following products are excluded from HS 283531, as this subheading is exclusively for sodium tripolyphosphate. Other polyphosphates, such as tetrasodium pyrophosphate (TSPP) or sodium hexametaphosphate (SHMP), are classified under HS 2835.39 ("Other polyphosphates"). Phosphates of metals other than sodium, or sodium phosphates that are not polyphosphates (e.g., disodium phosphate, trisodium phosphate), would fall under HS 2835.29 ("Other phosphates"). For instance, calcium polyphosphates, despite being polyphosphates, are not sodium tripolyphosphate and therefore are correctly classified under 2835.39, demonstrating the strict specificity of 2835.31.
What are common classification mistakes for HS 283531?
A common error is misclassifying other sodium polyphosphates, such as sodium hexametaphosphate or tetrasodium pyrophosphate, under HS 283531. This subheading is explicitly limited to "Sodium triphosphate (sodium tripolyphosphate)" as per the WCO HS nomenclature and national tariff schedules like the USITC HTS and EU TARIC. Importers sometimes overlook the precise chemical name, leading to incorrect classification under 2835.31 instead of the broader 2835.39 ("Other polyphosphates"). Adherence to General Interpretative Rule (GRI) 1, which states that classification is determined according to the terms of the headings and any relative section or chapter notes, is crucial here to ensure the correct chemical identity is matched to the specific subheading.
How should importers classify products under HS 283531?
The correct procedure for classifying products under HS 283531 involves verifying the precise chemical identity of the imported substance. Importers and customs brokers must confirm that the product is indeed "Sodium triphosphate (sodium tripolyphosphate)" and not another polyphosphate or a different sodium phosphate. This requires reviewing the product's chemical name, CAS number, and specifications provided by the manufacturer. Consulting the WCO Harmonized System Explanatory Notes for Heading 2835, along with national tariff schedules like the USITC HTS or EU TARIC, will confirm the specific scope of subheading 2835.31. If any doubt exists, obtaining a binding ruling from the relevant customs authority is recommended to ensure compliance and avoid potential penalties.
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FAQ
What are the typical Most Favored Nation (MFN) duty rates for HS code 2835.31 (Sodium Tripolyphosphate)?
The Most Favored Nation (MFN) duty rates for HS code 2835.31, specifically covering Sodium Tripolyphosphate, vary by importing country. For example, the United States applies an MFN duty rate of 3.5% ad valorem (Source: USITC Harmonized Tariff Schedule, Chapter 28). The European Union's TARIC database indicates a common MFN duty rate of 5.5% ad valorem for this heading (Source: EU TARIC). The UK Global Tariff also lists a 5.5% ad valorem MFN duty rate (Source: UK Trade Tariff). Importers should always verify the specific rate applicable to their destination country.
Which preferential trade agreements offer duty-free entry for Sodium Tripolyphosphate (HS 2835.31) into the United States?
For imports of Sodium Tripolyphosphate (HS 2835.31) into the United States, several Free Trade Agreements (FTAs) and preferential programs allow for duty-free entry. These include, but are not limited to, imports originating from countries party to agreements such as the Australia Free Trade Agreement (AU), Bahrain Free Trade Agreement (BH), Chile Free Trade Agreement (CL), Colombia Trade Promotion Agreement (CO), Dominican Republic-Central America Free Trade Agreement (DR-CAFTA, 'D' and 'E' for specific countries), Israel Free Trade Agreement (IL), Jordan Free Trade Agreement (JO), Korea Free Trade Agreement (KR), Morocco Free Trade Agreement (MA), Oman Free Trade Agreement (OM), Panama Trade Promotion Agreement (PA), Peru Trade Promotion Agreement (PE), Singapore Free Trade Agreement (SG), and others under the Generalized System of Preferences (GSP, 'A' for eligible developing countries). Importers must ensure compliance with the specific Rules of Origin for each agreement to claim preferential treatment.
What are the key classification criteria for distinguishing Sodium Tripolyphosphate (HS 2835.31) from other polyphosphates?
HS code 2835.31 specifically covers 'Sodium tripolyphosphate'. The primary classification criterion is the chemical identity of the substance. While Heading 2835 covers 'Phosphinates, phosphonates and phosphates; polyphosphates, whether or not chemically defined', subheading 2835.3 groups 'Polyphosphates'. Subheading 2835.31 then precisely identifies 'Sodium tripolyphosphate'. Importers must ensure that the product's chemical composition matches this specific compound. Laboratory analysis or a Certificate of Analysis (CoA) from the manufacturer confirming the chemical name and CAS number (e.g., CAS 7758-29-4 for Sodium Tripolyphosphate) is often crucial to avoid misclassification into other polyphosphate subheadings (e.g., 2835.39 for other polyphosphates).
Are there any specific documentation requirements for importing Sodium Tripolyphosphate (HS 2835.31)?
Beyond standard customs documentation such as the commercial invoice, packing list, and bill of lading/airway bill, importers of Sodium Tripolyphosphate (HS 2835.31) should be prepared to provide a Certificate of Analysis (CoA) or a Safety Data Sheet (SDS). These documents confirm the chemical identity, purity, and safety characteristics of the product, which can be critical for customs verification and compliance with chemical control regulations. If claiming preferential duty rates under a Free Trade Agreement, a valid Certificate of Origin or origin declaration is mandatory to substantiate the claim. Depending on the end-use or specific national regulations, additional permits or licenses from environmental or health authorities might be required, though this is less common for general industrial use of this specific chemical.