HS code · 6-digit subheading
HS Code 2903.51 – Unsaturated fluorinated derivatives of acyclic hydrocarbons; 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze) and (Z)-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz)
HS code 2903.51 is the 6-digit subheading for unsaturated fluorinated derivatives of acyclic hydrocarbons, 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze) and (Z)-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz). It is used for HFO-1234yf automotive refrigerant, HFO-1234ze refrigerant, HFO-1336mzz blowing agent, low-GWP refrigerants and aerosol propellants.
What HS 2903.51 covers
This crucial HS code covers hydrofluoroolefins (HFOs), a new generation of unsaturated fluorinated derivatives designed to replace high-GWP HFCs. Key compounds include HFO-1234yf, rapidly becoming the standard in automotive air conditioning, and HFO-1234ze and HFO-1336mzz, used in chillers, foam blowing, and aerosols. These HFOs offer ultra-low Global Warming Potential, making them environmentally preferable. International trade in HFOs is experiencing rapid growth as industries globally transition away from HFCs to meet environmental regulations. Major chemical companies are leading the production and export, with significant demand from automotive manufacturers, HVAC-R industries, and foam producers. Importers are typically countries with large manufacturing bases for these applications. The trade is heavily influenced by environmental regulations and phase-down mandates for HFCs, positioning HFOs as key sustainable alternatives for the future.
- Covers
- HFO-1234yf automotive refrigerant
- HFO-1234ze refrigerant
- HFO-1336mzz blowing agent
- Low-GWP refrigerants
- Aerosol propellants
- Foam insulation agents
- Chiller fluids
- Examples
- Chemours Opteon YF (HFO-1234yf)
- Honeywell Solstice YF (HFO-1234yf)
- Arkema Forane 1234yf
- Honeywell Solstice ze (HFO-1234ze)
Codes often confused with 2903.51
Common mistake. Can be confused with HFCs (2903.4x) due to similar applications, but HFOs are unsaturated and have significantly lower GWP, making the distinction critical for environmental compliance and trade regulations.
Top exporters and importers of HS code 290351, 2025
In 2025, the largest exporter of HS code 290351 in UN Comtrade data was the United States, with 39% of world exports; the largest importer in UN Comtrade data was the Netherlands, with 29% of world imports. Mexico reports $578M of its heading 2903 imports without product detail (confidential), so it may also belong among the top importers.
Top exporters 2025 · share of world exports
- 1 United States $611M 39% of world exports
- 2 Netherlands $508M 33% of world exports
- 3 China $295M 19% of world exports
World total: $1.6B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Netherlands $412M 29% of world imports
- 2 Germany $123M 8.7% of world imports
- 3 South Korea $122M 8.7% of world imports
Mexico reports $578M of its heading 2903 imports without product detail (confidential), so it may also belong among the top importers.
World total: $1.4B 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 that did not report are estimated from what other countries recorded trading with them. 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 2903.51
Brazil does not split HS 2903.51: its NCM code is 2903.51.00.
All Brazil NCM codes in heading 29.03 →
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text is official; the English is our translation.
Questions about HS 2903.51
What is HS code 290351?
HS code 290351 is a 6-digit subheading in the Harmonized System that covers: Unsaturated fluorinated derivatives of acyclic hydrocarbons; 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze) and (Z)-1,1,1,4,4,4-hexafluoro-2-butene (HFO-1336mzz). This crucial HS code covers hydrofluoroolefins (HFOs), a new generation of unsaturated fluorinated derivatives designed to replace high-GWP HFCs. Key compounds include HFO-1234yf, rapidly becoming the standard in automotive air conditioning, and HFO-1234ze and HFO-1336mzz, used in chillers, foam blowing, and aerosols. These HFOs offer ultra-low Global Warming Potential, making them environmentally preferable. International trade in HFOs is experiencing rapid growth as industries globally transition away from HFCs to meet environmental regulations. Major chemical companies are leading the production and export, with significant demand from automotive manufacturers, HVAC-R industries, and foam producers. Importers are typically countries with large manufacturing bases for these applications. The trade is heavily influenced by environmental regulations and phase-down mandates for HFCs, positioning HFOs as key sustainable alternatives for the future.
What products fall under HS code 290351?
HFO-1234yf automotive refrigerant, HFO-1234ze refrigerant, HFO-1336mzz blowing agent, low-GWP refrigerants, aerosol propellants, foam insulation agents, chiller fluids
What are common misclassifications for HS code 290351?
Can be confused with HFCs (2903.4x) due to similar applications, but HFOs are unsaturated and have significantly lower GWP, making the distinction critical for environmental compliance and trade regulations.
Which countries are the top exporters of goods under HS code 290351?
In 2025, the top exporters of HS code 290351 in UN Comtrade data were the United States ($611M, 39% of world exports), the Netherlands ($508M) and China ($295M). World exports came to about $1.6B, 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 goods under HS code 290351?
In 2025, the top importers of HS code 290351 in UN Comtrade data were the Netherlands ($412M, 29% of world imports), Germany ($123M) and South Korea ($122M). World imports came to about $1.4B, adding countries' reported figures and partner-based estimates for those that did not report (UN Comtrade data). Mexico reports $578M of its heading 2903 imports without product detail (confidential), so it may also belong among the top importers.
How is HS code 290351 structured?
HS code 290351 is a 6-digit subheading under the Harmonized System. The first 2 digits (29) identify the chapter, digits 3-4 (03) identify the heading, and digits 5-6 (51) specify the subheading. This code is standardized globally by the World Customs Organization.
What is the Brazil NCM code for HS code 290351?
In Brazil, HS code 290351 is NCM 2903.51.00. The last two digits are 00 because Brazil does not split this HS code further.