Product classification
HS code for PFOS: 2904.31
Derivatives of hydrocarbons, perfluorooctane sulphonic acid, whether or not halogenated.
Classification of PFOS under HS 2904.31
Perfluorooctane sulphonic acid (PFOS) is classified under HS code 2904.31 because it is a separate chemically defined organic compound. Specifically, it falls under Chapter 29, which covers organic chemicals, and heading 2904, which includes sulfonated, nitrated, or nitrosated derivatives of hydrocarbons. PFOS is a perfluorinated compound where the hydrogen atoms of the octane chain are replaced by fluorine, and it features a sulfonic acid functional group. The international community, through the World Customs Organization (WCO), established this specific subheading to facilitate the monitoring of substances regulated under the Stockholm Convention on Persistent Organic Pollutants (POPs). Classification here requires the product to be in its pure acid form, rather than a salt or a prepared mixture. The chemical purity must meet the standards of Chapter 29 notes to qualify for this specific code.
- Covers
- Perfluorooctane sulphonic acid (pure)
- Heptadecafluorooctane-1-sulphonic acid
- PFOS acid in aqueous solution (if not meeting mixture criteria)
- 1-Octanesulfonic acid, 1,1,2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-heptadecafluoro-
- Also under 2904.31
- 3M (historical producer of PFOS, now phased out)
- Chemours (fluorochemicals, but PFOS largely restricted)
- Daikin (fluorochemicals, but PFOS largely restricted)
Codes often confused with 2904.31
Common mistake. PFOS is frequently misclassified under HS code 2904.35, which is reserved for the salts of PFOS. It is also often confused with HS code 3824.87, which covers chemical mixtures containing PFOS. If the substance is not a separate chemically defined compound but is instead part of a preparation (like a firefighting foam), it must be moved to Chapter 38. Additionally, some importers mistakenly use 2903, which covers halogenated derivatives of hydrocarbons, but the presence of the sulfonic acid group mandates classification in 2904.
Top exporters and importers of HS 290431 (the code used for PFOS), 2025
In 2025, the largest exporter of HS 290431 (the code used for PFOS) in UN Comtrade data was Portugal, with 71% of world exports; the largest importer in UN Comtrade data was Nigeria, with 52% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Figures cover everything classified under HS 290431, not only PFOS.
Top exporters 2025 · share of world exports
- 1 Portugal $631K 71% of world exports
- 2 Egypt $66K 7.4% of world exports
- 3 Germany $56K 6.3% of world exports
World total: $894K Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Nigeria $485K 52% of world imports
- 2 Cape Verde* ~$105K 11% of world imports · partner records ↗
- 3 Algeria* ~$66K 7.1% of world imports · partner records ↗
World total: $931K Reported figures on UN Comtrade ↗
How these figures are built
109 countries reported 2025 trade to UN Comtrade in HS 2022, and their own totals are used. Countries marked * did not, so their figures add up what other countries recorded trading with them, and their exports are valued at buyers' CIF prices. Those estimates miss trade with other non-reporting countries, so they can be low, and a non-reporting country can rank higher than shown or be missing from the list. World totals add both and leave out trade between two non-reporting countries. Figures are in current US dollars; reported imports are mostly valued CIF and exports FOB, and exports include re-exports. The UN Comtrade links show the underlying records; they can also list a few reporters left out here (regional groups and older HS editions).
Source: UN Comtrade (United Nations Statistics Division), 2025 annual data.
Brazil NCM code for PFOS
Brazil classifies PFOS under NCM 2904.31.00: HS 2904.31 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about PFOS
What is the HS code for PFOS?
The HS code for PFOS is 290431 (Derivatives of hydrocarbons; perfluorooctane sulphonic acid, whether or not halogenated). The HS code for perfluorooctane sulphonic acid in its pure form is 2904.31.
How do I classify PFOS for customs?
PFOS is classified under HS code 290431 — Derivatives of hydrocarbons; perfluorooctane sulphonic acid, whether or not halogenated. This is a 6-digit subheading level code.
Does this code include PFOS salts?
No, PFOS salts are classified under HS code 2904.35, while the acid itself is 2904.31.
Which countries are the top exporters of PFOS (HS 290431)?
In 2025, the top exporters of HS 290431 (the code used for PFOS) in UN Comtrade data were Portugal ($631K, 71% of world exports), Egypt ($66K) and Germany ($56K). World exports came to about $894K, 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.
Which countries are the top importers of PFOS (HS 290431)?
In 2025, the top importers of HS 290431 (the code used for PFOS) in UN Comtrade data were Nigeria ($485K, 52% of world imports), Cape Verde (about $105K) and Algeria (about $66K). World imports came to about $931K, 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.
Is the HS code for PFOS the same in all countries?
The base HS code 290431 for PFOS is internationally standardized for the first 6 digits across 200+ countries. Individual countries may add additional digits for national tariff lines and specific classifications.
What is the NCM code for PFOS in Brazil?
In Brazil, PFOS (HS 290431) is classified under NCM 2904.31.00.