HS code · 6-digit subheading
HS Code 3907.21 – Polyethers other than polyacetals; in primary forms, bis(polyoxyethylene) methylphosphonate
HS code 3907.21 is the 6-digit subheading for polyethers other than polyacetals, in primary forms, bis(polyoxyethylene) methylphosphonate. It is used for bis(polyoxyethylene) methylphosphonate, flame retardant polyether, reactive flame retardant, additive flame retardant and phosphonate polyether.
What HS 3907.21 covers
This specific HS code covers bis(polyoxyethylene) methylphosphonate in primary forms. This compound is a specialized polyether, distinct from polyacetals, and is primarily recognized for its flame-retardant properties. It functions as a reactive or additive flame retardant in various polymer systems, enhancing fire safety in materials without significantly compromising their mechanical properties. Its application is crucial in industries where fire safety standards are stringent, such as electronics, construction, and textiles. Major importers are typically countries with robust manufacturing sectors that produce flame-retardant plastics, coatings, and textiles, including China, Germany, and the USA. Exporters are often nations with advanced chemical synthesis capabilities. The trade in this particular polyether is driven by the increasing global demand for fire-safe materials and the need to comply with evolving safety regulations across various product categories.
- Covers
- Bis(polyoxyethylene) methylphosphonate
- Flame retardant polyether
- Reactive flame retardant
- Additive flame retardant
- Phosphonate polyether
- Examples
- Clariant Exolit OP
- Lanxess Disflamoll
- ICL Industrial Products FR-2000
- Adeka FP series
Codes often confused with 3907.21
Common mistake. This code can be confused with 390729 (other polyethers, not bis(polyoxyethylene) methylphosphonate) if the specific chemical identity is not precisely known, or with other flame retardants in different chemical classes.
Top exporters and importers of HS code 390721, 2025
In 2025, the largest exporter of HS code 390721 in UN Comtrade data was the United States, with 37% of world exports; the largest importer in UN Comtrade data was Belgium, with 20% of world imports. Countries that did not report 2025 data are estimated from partner records, which can understate them.
Top exporters 2025 · share of world exports
- 1 United States $21M 37% of world exports
- 2 China $13M 21% of world exports
- 3 Russia* ~$5.1M 8.7% of world exports · partner records ↗
World total: $58M Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 Belgium $41M 20% of world imports
- 2 France $27M 13% of world imports
- 3 Poland $26M 13% of world imports
World total: $203M 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 3907.21
Brazil does not split HS 3907.21: its NCM code is 3907.21.00.
All Brazil NCM codes in heading 39.07 →
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text is official; the English is our translation.
Questions about HS 3907.21
What is HS code 390721?
HS code 390721 is a 6-digit subheading in the Harmonized System that covers: Polyethers other than polyacetals; in primary forms, bis(polyoxyethylene) methylphosphonate. This specific HS code covers bis(polyoxyethylene) methylphosphonate in primary forms. This compound is a specialized polyether, distinct from polyacetals, and is primarily recognized for its flame-retardant properties. It functions as a reactive or additive flame retardant in various polymer systems, enhancing fire safety in materials without significantly compromising their mechanical properties. Its application is crucial in industries where fire safety standards are stringent, such as electronics, construction, and textiles. Major importers are typically countries with robust manufacturing sectors that produce flame-retardant plastics, coatings, and textiles, including China, Germany, and the USA. Exporters are often nations with advanced chemical synthesis capabilities. The trade in this particular polyether is driven by the increasing global demand for fire-safe materials and the need to comply with evolving safety regulations across various product categories.
What products fall under HS code 390721?
Bis(polyoxyethylene) methylphosphonate, flame retardant polyether, reactive flame retardant, additive flame retardant, phosphonate polyether
What are common misclassifications for HS code 390721?
This code can be confused with 390729 (other polyethers, not bis(polyoxyethylene) methylphosphonate) if the specific chemical identity is not precisely known, or with other flame retardants in different chemical classes.
Which countries are the top exporters of goods under HS code 390721?
In 2025, the top exporters of HS code 390721 in UN Comtrade data were the United States ($21M, 37% of world exports), China ($13M) and Russia (about $5.1M). World exports came to about $58M, 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 390721?
In 2025, the top importers of HS code 390721 in UN Comtrade data were Belgium ($41M, 20% of world imports), France ($27M) and Poland ($26M). World imports came to about $203M, 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.
How is HS code 390721 structured?
HS code 390721 is a 6-digit subheading under the Harmonized System. The first 2 digits (39) identify the chapter, digits 3-4 (07) identify the heading, and digits 5-6 (21) specify the subheading. This code is standardized globally by the World Customs Organization.
What is the Brazil NCM code for HS code 390721?
In Brazil, HS code 390721 is NCM 3907.21.00. The last two digits are 00 because Brazil does not split this HS code further.