Perfluorooctane sulfonyl fluoride (POSF) is the key precursor chemical from which PFOS and its salts are synthesized, making it a critical upstream input in the PFAS supply chain. Ukraine is the primary US import source for this substance, entering under tariff line 2904360000. Given its role as a PFAS precursor, POSF is subject to EPA TSCA scrutiny, and importers should assess whether current TSCA Section 5 significant new use rules or import certification requirements apply.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
POSF is the sulfonyl fluoride form of the compound, not a sulfonate salt, and is assigned its own HS6 heading (290436) and US tariff line (2904360000). This distinction is commercially significant because POSF is primarily a synthetic intermediate rather than an end-use product, and its classification, duty treatment, and regulatory obligations differ from those of the finished PFOS salt forms.
Beyond standard commercial invoice and packing list requirements, importers of POSF should be prepared to provide TSCA certification (either 'subject to TSCA' or 'not subject to TSCA') at entry. Given ongoing geopolitical developments affecting Ukrainian trade logistics, importers should also verify export licensing requirements on the Ukrainian side and confirm carrier availability and insurance terms.
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Subheading 9 of 10 in heading 2904
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Imports for consumption | Average duty rate | Dutiable Share |
|---|---|---|---|---|
| 2904360000 | Perfluorooctane Sulfonyl Fluoride | — | -- | -- |
Imports
Imports
—YoY · free account
Low of 1 reported month · imports
Low · free accountFewer than 6 of the last 12 months reported trade, or the latest month was under $500K; the trend chart is not shown for thin series.
Through August 2026 · imports 1 of 12 months reported. Source: U.S. Census Bureau.
Imports · August 2026
origin
customs district
destination
entry
rate provision · imports
None recorded for this period.