Sourcing THPS from China
Tetrakis hydroxymethyl phosphonium sulphate from China carries 0% to 6% UK duty: the suspension requires the named substance at 70% purity or above and excludes preparations. For biocidal supply in Great Britain, check the intended use and supplier compliance before ordering. Cambridge China Bridge sources tetrakis hydroxymethyl phosphonium sulphate.
THPS duty and the conditional suspension
Read from the UK Trade Tariff on 1 October 2026, heading 2931 covers other organo-inorganic compounds. Tetrakis hydroxymethyl phosphonium sulphate, also named bis[tetrakis(hydroxymethyl)phosphonium] sulphate, is relevant to residual code 2931 49 80 90. The supplied tariff data contains only this relevant line, so the table does not include unrelated chemicals.
The base duty for Chinese-origin goods is 6%, with no anti-dumping or countervailing measure recorded. A 0% suspension applies to the named substance, CAS RN 55566-30-8, with purity by weight of 70% or more. Its footnotes exclude mixtures, preparations and products made up of different components containing it. Do not assume that a formulated biocide qualifies.
The UK Trade Tariff also attaches an export control for waste to this line. Ask your customs broker to confirm its relevance to the shipment, particularly for rejected material being returned overseas. Confirm the commodity code from the complete composition and check suspension eligibility before shipment. See the wider phosphonate guide for related chemicals.
| Goods | Commodity code | Duty | Anti-dumping or countervailing duty on China |
|---|---|---|---|
| Tetrakis hydroxymethyl phosphonium sulphate | 2931 49 80 90 | 6% | None |
Specify the sulphate, concentration and intended use
Specify the full sulphate name and CAS RN 55566-30-8, not just a supplier’s water-treatment trade name. Agree active content by weight, the assay method, appearance, acidity, density and limits for residual formaldehyde and other relevant impurities. Ask the factory to identify water and every added ingredient. Distinguish chemical feedstock from a finished biocidal formulation.
For biocidal supply in Great Britain, check the product’s compliance for its intended use before placing it on the market. Check the relevant supplier and product-type combination against the GB Article 95 List and obtain an auditable supply trail. HSE also advises checking whether UK REACH applies. Arrange a testing and certification review around the actual composition and use.
Worked duty example
Illustrative example, not a quote: Illustrative trial consignment of tetrakis hydroxymethyl phosphonium sulphate in drums under 2931 49 80 90, invoiced at £4,000 free on board, with £2,400 of freight and insurance to the UK. The customs value is £6,400. Duty at 6% is £384. Import VAT at 20% is charged on the customs value plus duty, £6,784, so it is £1,356.80. Import taxes total £1,740.80; a VAT-registered importer can usually reclaim the VAT, so the lasting cost is the £384 of duty. The import duty and VAT guide explains each step.
Inspection checklist
Identity: match the order, container labels, safety data sheet and batch certificate to the sulphate name and agreed composition.
Assay: use the agreed test method to check active content against the contract; review the batch result separately from any claim to suspension eligibility.
Condition: compare appearance, acidity, density and agreed impurity results with the approved sample; investigate unexpected sediment or colour changes.
Containers and documents: inspect closures, seals, leaks and batch identification. Check classification, labels and packaging before market supply. A hazardous chemical supplied for workplace use needs a safety data sheet.
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What goes wrong
A trade name conceals a different concentration or added ingredients, the certificate reports a result without the agreed assay method, or a batch falls below the contracted active content. Leaking closures and inconsistent batch identifiers make arrival checks harder. Keep a retained sample and agree how disputed results will be resolved.
The purchasing mistake is treating tariff relief as permission to sell a biocide. Check the intended use and supply trail separately from the customs rate. A supplier’s generic compliance statement does not replace the auditable trail required for biocidal supply. Resolve composition and suspension questions before accepting a duty estimate.
Cambridge China Bridge sources these products for UK businesses, checking the factory and the documents before shipment. See factory verification. For repeat volumes, see container programmes.
Frequently asked questions
What is the UK import duty on THPS from China?
The base rate is 6%. The named substance at 70% purity by weight or above has a conditional 0% suspension; its footnotes exclude mixtures and preparations. No anti-dumping or countervailing measure is recorded.
Does every THPS solution qualify for zero duty?
Do not assume so. Check the named substance, purity and suspension exclusions against the complete composition with your customs broker.
Can I sell imported THPS as a biocide?
Check compliance for the intended use before market supply, including the relevant GB Article 95 supplier entry and auditable supply trail. A customs suspension does not establish biocide compliance.
What should I test in a THPS batch?
Check identity and active content using the agreed assay method, then appearance, acidity, density and contracted impurity limits. Match results to the delivered batch and retain a comparison sample.