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HSChapter 29
U.S. exports of buta-1,3-diene and isoprene (HS 290124) totaled $21.0M in July 2026.
Importers of Buta-1,3-Diene and Isoprene paid $839K in duties in July 2026 — an effective duty rate of 10% on $8.4M in dutiable value, based on actual customs collections rather than the published tariff schedule. Buta-1,3-Diene and Isoprene imports of $15.9M in July 2026 ran 19% below the year-to-date monthly average of $19.7M.
Last updated: July 2026 dataButa-1,3-diene and isoprene are conjugated diene hydrocarbons that serve as the primary monomers for synthetic rubber — including styrene-butadiene rubber (SBR) and polyisoprene — making them indispensable to the tire and automotive industries. The US HTS schedule distinguishes isoprene by purity threshold: line 2901242000 covers isoprene at 95% or greater purity by weight, while 2901245000 covers lower-purity isoprene, and 2901243000 captures isoprene not otherwise specified. Canada and South Korea are the leading US import sources, with the Netherlands, Taiwan, and Brazil also supplying the market. Correct purity documentation is essential for proper tariff-line classification of isoprene shipments.
AI-written summary of the official U.S. Census Bureau trade figures on this page — verify before relying on it.
89 shipments/mo
The US schedule separates isoprene by purity: 2901242000 applies to isoprene with a purity of 95% or more by weight, 2901245000 to isoprene below that threshold, and 2901243000 to isoprene not elsewhere specified. A certified certificate of analysis (CoA) stating the purity percentage is the key document for determining the correct classification and should accompany every shipment.
Buta-1,3-diene is a byproduct of steam cracking, so its availability is closely tied to ethylene production rates and naphtha cracker utilization. Supply tightness in Canada or South Korea — the leading US sources — can quickly affect downstream synthetic rubber manufacturers. Importers relying on a single origin should monitor cracker turnaround schedules and consider maintaining strategic inventory buffers.
Subheading 3 of 6 in heading 2901
Subheading 290124 · $15.9M of $110.9M
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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 |
|---|---|---|---|---|---|
| 2901242000 | Isoprene Purity of 95% or More by Weight | $8.4M | 10.00% | 100.00% | $839K |
| 2901241000 | Buta-1,3-Diene | $7.5M | 0.00% | 0.00% | -- |
| 2901245000 | Isoprene Purity Less Than 95% by Weight | $0 | -- | -- | -- |
HS10 export codes under this HS6 parent, each with its own page. Source: U.S. Schedule B export classification.
| Code | Description | Export Value |
|---|---|---|
| 2901241000 | Buta-1,3-Diene and Isomer Thereof, Unsaturated | $18.9M |
| 2901243000 | Isoprene | $2.1M |
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
$15.9MYoY · Pro
Exports
$21.0MYoY · Pro
12-mo low · imports
YoY · ProThrough July 2026. Source: U.S. Census Bureau.
Exports · July 2026
destination
Korea, South and Mexico together take 99% of it.
customs district
origin
entry
rate provision · imports
47.2% enters free of duty; the effective duty rate is 5.28%.