Product classification
HS code for BIIR rubber: 4002.39
Rubber, synthetic, halo-isobutene-isoprene rubber (CIIR or BIIR), in primary forms or in plates, sheets or strip.
Classification of BIIR rubber under HS 4002.39
BIIR rubber, or Bromobutyl rubber, is classified under HS code 4002.39. This classification falls within Chapter 40, which covers rubber and articles thereof. Heading 4002 is dedicated to synthetic rubber and factice derived from oils, in primary forms or in plates, sheets, or strip. Within this heading, subheading 4002.31 and 4002.39 cover halo-isobutene-isoprene rubber, commonly known as halogenated butyl rubber. While 4002.31 is specifically reserved for chlorobutyl rubber (CIIR), 4002.39 is the "other" category that captures bromobutyl rubber (BIIR). BIIR is produced by brominating butyl rubber, which enhances its vulcanization rate and compatibility with other elastomers like natural rubber. The classification is determined by the chemical composition of the synthetic rubber and its physical form. To qualify for this code, the BIIR must be in a primary form, such as bales, blocks, or crumbs, or in unvulcanized plates, sheets, or strips. Once the rubber is vulcanized or manufactured into a finished product, it moves to different headings within Chapter 40.
- Covers
- Bromobutyl rubber (BIIR) in bales
- Halogenated isobutene-isoprene rubber (brominated)
- BIIR rubber sheets (unvulcanized)
- Bromobutyl rubber crumbs or pellets
- Also under 4002.39
- Arlanxeo Chlorobutyl
- ExxonMobil Bromobutyl
- Lanxess Bromobutyl
- Tubeless tire inner liners
- Pharmaceutical bottle stoppers
Codes often confused with 4002.39
Common mistake. BIIR is frequently confused with CIIR (Chlorobutyl rubber), which is classified under HS code 4002.31. While both are halogenated butyl rubbers, the specific halogen used (Bromine vs. Chlorine) dictates the subheading. Another common error is classifying BIIR under 4002.30 (the general heading for butyl rubber) without specifying the halogenated nature, or under 4002.11/4002.19 if it is mistaken for Styrene-butadiene rubber (SBR). Furthermore, if the BIIR is already vulcanized, it should be classified under 4008 (plates/sheets) or 4016 (other articles), not 4002.
Top exporters and importers of HS 400239 (the code used for BIIR rubber), 2025
In 2025, the largest exporter of HS 400239 (the code used for BIIR rubber) in UN Comtrade data was the United States, with 23% of world exports; the largest importer in UN Comtrade data was China, with 18% 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 400239, not only BIIR rubber.
Top exporters 2025 · share of world exports
- 1 United States $336M 23% of world exports
- 2 Singapore $300M 20% of world exports
- 3 Belgium $236M 16% of world exports
World total: $1.5B Reported figures on UN Comtrade ↗
Top importers 2025 · share of world imports
- 1 China $310M 18% of world imports
- 2 Belgium $224M 13% of world imports
- 3 India $116M 6.8% of world imports
World total: $1.7B 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 BIIR rubber
Brazil classifies BIIR rubber under NCM 4002.39.00: HS 4002.39 with 00 added.
Source: Siscomex NCM table, updated Oct 2026. The Portuguese text on each NCM page is the official one.
Questions about BIIR rubber
What is the HS code for BIIR rubber?
The HS code for BIIR rubber is 400239 (Rubber; synthetic, halo-isobutene-isoprene rubber (CIIR or BIIR), in primary forms or in plates, sheets or strip). The HS code for BIIR (Bromobutyl) rubber is 4002.39, covering halogenated isobutene-isoprene rubber other than chlorobutyl.
How do I classify BIIR rubber for customs?
BIIR rubber is classified under HS code 400239 — Rubber; synthetic, halo-isobutene-isoprene rubber (CIIR or BIIR), in primary forms or in plates, sheets or strip. This is a 6-digit subheading level code.
Can BIIR rubber be classified under 4002.31?
No, 4002.31 is specifically for Chlorobutyl rubber (CIIR). Bromobutyl rubber must be classified under the "other" category, 4002.39.
Which countries are the top exporters of BIIR rubber (HS 400239)?
In 2025, the top exporters of HS 400239 (the code used for BIIR rubber) in UN Comtrade data were the United States ($336M, 23% of world exports), Singapore ($300M) and Belgium ($236M). World exports came to about $1.5B, 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 BIIR rubber (HS 400239)?
In 2025, the top importers of HS 400239 (the code used for BIIR rubber) in UN Comtrade data were China ($310M, 18% of world imports), Belgium ($224M) and India ($116M). World imports came to about $1.7B, 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 BIIR rubber the same in all countries?
The base HS code 400239 for BIIR rubber 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 BIIR rubber in Brazil?
In Brazil, BIIR rubber (HS 400239) is classified under NCM 4002.39.00.