U.S. imports of HFO-1234yf, HFO-1234ze, and HFO-1336mzz (HS 290351) totaled $6.1M in September 2026, imported from 6 countries.
Importers of HFO-1234yf, HFO-1234ze, and HFO-1336mzz paid $802K in duties in September 2026, an average duty rate of 13.23% — duty actually collected as a share of the imports that cleared customs, not the published tariff schedule.
Last updated: September 2026 dataHydrofluoroolefins (HFOs) represent the next-generation refrigerant technology designed to replace high-GWP HFCs in automotive air conditioning, commercial refrigeration, and foam-blowing applications. HFO-1234yf has become the mandated refrigerant for new passenger vehicle AC systems in the US and EU, driving substantial import demand. China leads US supply under tariff line 2903511000, with Mexico and South Korea as significant secondary sources. These compounds are unsaturated and chemically distinct from HFCs, giving them dramatically lower global warming potentials, which is why they are classified separately under heading 2903.51 rather than with saturated HFCs.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
44 import shipments a month
HFOs contain a carbon-carbon double bond, making them unsaturated fluorinated derivatives, while HFCs are fully saturated. The HS nomenclature separates saturated and unsaturated halogenated hydrocarbons, placing HFOs in heading 2903.51 and saturated HFCs in earlier subheadings. This chemical distinction also underlies their much lower atmospheric lifetimes and GWP values.
China is the dominant import source, which creates concentration risk, particularly given Section 301 tariff exposure on Chinese-origin chemical imports. Automotive OEM supply chains have tight specification and continuity requirements, so importers should assess alternative sources in South Korea and Mexico and maintain safety stock to buffer against trade-policy or logistics disruptions.
Trade Directory
List your company under HS 290351 — HFO-1234yf, HFO-1234ze, and HFO-1336mzz, so the companies trading it can find you. Be the first supplier listed.
Subheading 3 of 41 in heading 2903
Subheading 290351 · $6.1M of $50.6M
ImportsExports
Imports
$6.1MYoY · free account
Exports
—YoY · free account
12-mo low · imports
Low · free accountOver the twelve months to September 2026, the U.S. imported $80.7M of HFO-1234yf, HFO-1234ze, and HFO-1336mzz.
Through September 2026 · exports 11 of 12 months reported. Source: U.S. Census Bureau.
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 | Duty Collected |
|---|---|---|---|---|---|
| 2903511000 | Hfo-1234yf, Hfo-1234ze and Hfo-1336mzz | $4.9M | 12.90% | 82.07% | $636K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 2903511000 | Hfo-1234yf, Hfo-1234ze and Hfo-1336mzz | $35.6M |
Import lines come from the U.S. Harmonized Tariff Schedule and export lines from Schedule B. The two are numbered by different agencies, so the same 10-digit code can appear in both tables describing a different product.
Imports · September 2026
origin
China and Mexico together supply 86% of it. China pays 16.2% duty; Mexico 0.0%.
customs district
destination
entry
rate provision · imports
15.9% enters free of duty; duty collected equals 13.23% of imports for consumption.