HS 290123 Butene (butylene) and isomers thereof
Quick Answer: HS code 2901.23 covers butene (butylene) and its various isomers, which are unsaturated acyclic hydrocarbons containing four carbon atoms. These petrochemicals are crucial intermediates in the chemical industry, primarily used in the production of polymers like polybutene, synthetic rubber, and various organic chemicals. For importers and exporters, the duty rates are notably favorable across major jurisdictions. The United Kingdom and the European Union both apply a 0.00% ad valorem duty rate. Similarly, the United States imposes a "Free" duty rate, indicating no customs duties are levied. This widespread duty-free status simplifies trade and reduces landed costs, making it an attractive commodity for international commerce, particularly for industries reliant on these foundational chemical building blocks.
What Are the Import Duty Rates?
🇬🇧 United Kingdom
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2901230000 | 0.00 % | — | — |
🇪🇺 European Union (TARIC)
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2901230000 | 0.00 % | — | — |
🇺🇸 United States (HTSUS)
| Code | MFN | Preferential | Unit |
|---|---|---|---|
| 2901230000 | Free | — | ["kg"] |
Duty rates sourced from the USITC (US International Trade Commission) Harmonized Tariff Schedule (HTS) (accessed 2/22/2026), EU TARIC – DG TAXUD (Directorate-General for Taxation and Customs Union) (accessed 2/22/2026), and UK Trade Tariff – HMRC (His Majesty's Revenue and Customs) (accessed 2/22/2026).
Data compiled and presented by HSRates.
How Has Trade Volume Developed?
How to Classify This HS Code?
What products does HS 290123 cover?
This subheading covers butene (butylene) and its isomers, which are unsaturated acyclic hydrocarbons containing one double bond and four carbon atoms. Specifically, this includes 1-butene, cis-2-butene, trans-2-butene, and isobutene (2-methylpropene). These compounds are crucial intermediates in the petrochemical industry, used in the production of polymers, synthetic rubber, and various organic chemicals. The scope is precisely defined by the Harmonized System Nomenclature, as interpreted by the World Customs Organization (WCO), and reflected in national tariffs such as the USITC Harmonized Tariff Schedule (HTS) under subheading 2901.23.00 and the EU TARIC system for 2901 23 00.
What falls outside HS 290123?
The following products are excluded from HS 290123: saturated acyclic hydrocarbons, such as butane (HS 2901.10), which lack the double bond characteristic of butenes. Also excluded are cyclic hydrocarbons, even if they contain four carbon atoms, as their ring structure places them in different subheadings, typically within HS 2902. Furthermore, butenes that have undergone further chemical modification, such as halogenation or oxygenation, are excluded, as they would be classified under more specific headings within Chapter 29 based on their new functional groups, for example, halogenated derivatives of hydrocarbons in HS 2903.
What are common classification mistakes for HS 290123?
A common error is misclassifying mixtures containing butenes. If butene is not in a pure form or is part of a mixture where another component imparts the essential character, it may not fall under HS 290123. For instance, a mixture of butene and propane, where propane predominates by weight or value, would likely be classified elsewhere, potentially under HS 2711 for petroleum gases and other gaseous hydrocarbons, applying General Interpretative Rule (GRI) 3(b). Another mistake involves confusing butenes with their saturated counterpart, butane, leading to incorrect classification under HS 2901.10. Careful chemical analysis and understanding of the product's primary function are essential to avoid these errors.
How should importers classify products under HS 290123?
The correct procedure for classifying products under HS 290123 involves several steps for importers and customs brokers. First, verify the chemical identity of the product to confirm it is indeed butene or one of its isomers, ensuring no other functional groups are present that would lead to classification elsewhere in Chapter 29. Obtain a Certificate of Analysis (CoA) or Safety Data Sheet (SDS) from the manufacturer, which typically specifies the chemical name, CAS number, and purity. Consult the WCO Explanatory Notes for Heading 2901 and subheading 2901.23 for detailed guidance. Finally, cross-reference with the specific national tariff (e.g., USITC HTS or EU TARIC) to confirm the exact subheading and applicable duty rates, such as the 3.5% ad valorem duty rate for HS 2901.23.00 in the United States for Most Favored Nation (MFN) countries.
Which HS Codes Are Related?
Not the right code? Search all HS codes to find the correct tariff classification.
FAQ
What are the typical import duty rates for HS code 2901.23 (Butene and isomers thereof) in major markets?
For HS code 2901.23, many major trading blocs apply a Most Favored Nation (MFN) duty rate of 0.00% ad valorem. For example, the United States (under the Harmonized Tariff Schedule of the United States, HTSUS), the European Union (EU TARIC), and the United Kingdom (UK Trade Tariff) generally assess a 'Free' or '0.00%' duty rate for imports of butene and its isomers from MFN countries. Importers should always verify the specific duty rate applicable to their country of origin via the official tariff databases (e.g., USITC HTSUS, EU TARIC, UK Trade Tariff).
What are the key classification criteria for butene and its isomers under HS 2901.23?
HS code 2901.23 specifically covers 'Butene (butylene) and isomers thereof.' This heading falls under Chapter 29, which is dedicated to Organic Chemicals. The primary classification criterion is the chemical identity of the substance: it must be an acyclic hydrocarbon with four carbon atoms and one double bond (C4H8), or any of its isomeric forms (e.g., 1-butene, 2-butene, isobutylene). Importers must ensure that the chemical composition and purity align with the description. This excludes cyclic hydrocarbons, saturated hydrocarbons (alkanes), or hydrocarbons with different carbon counts or multiple double bonds (which would fall under other subheadings within Chapter 29 or 27).
Are there any common trade agreements that offer preferential duty treatment for butene and its isomers (HS 2901.23), even though the MFN rate is often 0%?
While the MFN duty rate for HS 2901.23 is frequently 0.00% or 'Free' in many countries, meaning no further preferential reduction is possible, certain trade agreements may still be relevant for other customs procedures or rules of origin. For instance, under agreements like the USMCA (United States-Mexico-Canada Agreement), EU-Japan EPA, or the UK-EU Trade and Cooperation Agreement, even with a 0% MFN rate, the product's originating status might be important for statistical purposes, safeguard measures, or future tariff changes. Importers should still ensure they meet the Rules of Origin requirements of any applicable free trade agreement (FTA) to claim preferential treatment, even if the current tariff is zero.
What specific documentation is typically required by customs authorities for importing butene and its isomers under HS 2901.23?
For HS 2901.23, standard import documentation includes a commercial invoice, packing list, bill of lading or air waybill, and potentially a certificate of origin if claiming preferential treatment under a trade agreement (even with a 0% MFN rate). Due to the nature of butene as a chemical, a Safety Data Sheet (SDS) is often required or highly recommended for customs and regulatory compliance, providing critical information on handling, hazards, and emergency procedures. Depending on the importing country's chemical regulations, additional permits or declarations related to chemical control laws (e.g., TSCA in the US, REACH in the EU) may be necessary. Importers should consult the specific requirements of the destination country's customs and environmental agencies.