Analysis
HTS 2901.23.00 covers butene (Butylene) and isomers thereof under heading 2901 (acyclic hydrocarbons).
The normal trade relations rate here is zero, shared by about 26% of the 1050 tariff lines in chapter 29, a useful check when a neighbouring dutiable line is a candidate. Free here means free of the base duty only: origin-specific Chapter 99 duties such as Section 301 can still be owed.
Census statistics map these goods to NAICS 325110 (Petrochemical Manufacturing), an industry of 76 US establishments employing 10,888 people. That concordance is how imports of this line are compared with US output.
All 11 neighbouring lines carry the same duty-free rate, so a borderline choice between them changes the statistics reported, not the duty paid.
The general rate of Free has not changed in any edition of the schedule since Jan 2023.
Neighbouring lines
| Line | Description | General rate |
|---|---|---|
| 2901.10.10 | Saturated: ethane and butane | Free |
| 2901.10.30 | n-Pentane and isopentane | Free |
| 2901.10.40 | Derived in whole or in part from petroleum, shale oil or natural gas | Free |
| 2901.10.50 | Other: other | Free |
| 2901.21.00 | Unsaturated: ethylene | Free |
| 2901.22.00 | Propene (Propylene) | Free |
| 2901.24.10 | Buta-1,3-diene and isoprene: buta-1,3-diene | Free |
| 2901.24.20 | Having a purity of 95 percent or more by weight | Free |
| 2901.24.50 | Isoprene: other | Free |
| 2901.29.10 | Derived in whole or in part from petroleum, shale oil or natural gas | Free |
| 2901.29.50 | Other: other | Free |