IRS Adds Two Rubber Chemicals to Superfund Excise Tax List Effective 2026
IRS adds two rubber chemicals to Superfund excise tax list, effective October 1, 2026, with retroactive refund claims.
Why it matters: In-house tax, legal, and compliance professionals must prepare for new reporting and payment duties related to these specific rubber substances under Superfund tax rules.
- IRS updated the Superfund chemical excise tax list on June 26, 2026, adding two rubber substances: chloro-isobutene-isoprene rubber and ethylene-propylene-dicyclopentadiene rubber.
- The new tax obligations take effect October 1, 2026, with eligible refund claims dating back to April 1, 2023.
- The excise tax was reinstated by the Infrastructure Investment and Jobs Act, effective July 1, 2022.
- Petitions to add these substances were filed by Arlanxeo USA LLC and Arlanxeo Canada Inc.
On June 26, 2026, the IRS published a notice updating the list of chemicals subject to the Superfund chemical excise tax. The two newly added substances are chloro-isobutene-isoprene rubber and ethylene-propylene-dicyclopentadiene rubber, both synthetic rubbers used in specialized industrial applications.
This expansion means companies manufacturing or importing these rubber chemicals must comply with Superfund excise tax obligations starting October 1, 2026. Additionally, refund claims for taxes paid on these substances apply retroactively from April 1, 2023.
The reinstatement of Superfund chemical excise taxes was enacted through the Infrastructure Investment and Jobs Act, effective July 1, 2022. It revived taxes on certain hazardous substances to fund environmental cleanup efforts.
The IRS's update followed formal petitions filed by Arlanxeo USA LLC and Arlanxeo Canada Inc., major producers of specialty synthetic rubbers, requesting these chemicals' inclusion on the excise tax list.
For legal and tax teams, this change requires evaluating the impact on tax reporting, payment processes, and contractual arrangements. Firms should review IRS resources for detailed guidance to ensure compliance and avoid penalties.
By the numbers:
- June 26, 2026 — IRS updated the taxable chemical list
- October 1, 2026 — Effective date for tax on added chemicals
- April 1, 2023 — Start date for refundable tax claims on these substances
Yes, but: The IRS has not yet published specific tax rates for these two rubber chemicals, which may affect precise compliance planning.
What's next: Companies should monitor IRS updates and ensure system readiness ahead of the October 2026 effective date.