Loading...
HSChapter 40
U.S. exports of halobutyl rubber — chlorobutyl (ciir) & bromobutyl (biir) (HS 400239) totaled $40.1M in July 2026.
Importers of Halobutyl Rubber — Chlorobutyl (CIIR) & Bromobutyl (BIIR) paid $89K in duties in July 2026 — an effective duty rate of 10% on $888K in dutiable value, based on actual customs collections rather than the published tariff schedule.
Last updated: July 2026 dataHalogenation of butyl rubber — chlorination to produce CIIR or bromination to produce BIIR — introduces reactive halogen sites that dramatically improve cure compatibility with general-purpose rubbers and accelerate vulcanization rates, making halobutyl the standard inner liner compound in tubeless radial tires. Canada and the United Kingdom are the leading US suppliers, reflecting the limited number of global facilities capable of the halogenation process. Both CIIR and BIIR are classified under the single tariff line 4002390000. BIIR's faster cure rate and better adhesion to tire carcass compounds have made it the preferred choice for high-performance and truck tire liners, while CIIR remains competitive in cost-sensitive applications.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
93 shipments/mo
Both CIIR and BIIR fall under the same tariff line (4002390000), so the distinction does not affect duty liability. However, commercial invoices and certificates of analysis should clearly identify the halogen type (chloro vs. bromo), Mooney viscosity, and halogen content percentage, as these are the parameters buyers and compounders use to verify grade conformance. Accurate documentation also supports any future scope ruling or audit defense.
Halobutyl production requires dedicated halogenation reactors integrated with butyl rubber polymerization lines, representing significant capital investment that limits the number of viable production sites globally. The Canadian facilities benefit from proximity to US tire manufacturers and established feedstock supply chains, while UK production reflects legacy investments by major elastomer companies. This concentration means US importers have limited alternative qualified sources, making long-term supply agreements and inventory management particularly important.
Subheading 7 of 14 in heading 4002
Subheading 400239 · $4.0M of $116.1M
Supplier Network
Get discovered by U.S. importers searching for HS 400239 — Halobutyl Rubber — Chlorobutyl (CIIR) & Bromobutyl (BIIR). Be the first supplier listed.
HS10 import codes under this HS6 parent, each with its own page. Source: U.S. Harmonized Tariff Schedule.
| Code | Description | Import Value | Effective Tariff % | Dutiable Share | Duty Collected |
|---|---|---|---|---|---|
| 4002390000 | Halo-Isobutene-Isoprene Rubber, NESOI | $4.0M | 2.23% | 22.33% | $89K |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 4002390000 | Halo-Isobutene-Isoprene Rubber, NESOI | $40.1M |
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.
ImportsExports
Imports
$4.0MYoY · Pro
Exports
$40.1MYoY · Pro
12-mo low · imports
YoY · ProThrough July 2026. Source: U.S. Census Bureau.
Exports · July 2026
destination
Brazil and Belgium together take 40% of it.
customs district
origin
entry
rate provision · imports
77.7% enters free of duty; the effective duty rate is 2.23%.