IRS Seeks Comment on Adding MDI to Superfund Tax List
Huntsman International's request to tax methylene diphenyl diisocyanate is open for comment through Oct. 26, 2026.
The Internal Revenue Service announced a notice of filing for a petition submitted under Rev. Proc. 2022-26, as modified by Rev. Proc. 2023-20, that seeks to add methylene diphenyl diisocyanate (MDI) to the list of taxable substances under section 4672(a) of the Internal Revenue Code. The petition was filed by Huntsman International LLC, an exporter and importer of MDI.
The filing lists the HTSUS and Schedule B number as 2929.10.8010 and the CAS numbers as 101-68-8 and 9016-87-9. It proposes a tax rate of $10.20 per ton, using conversion factors of 0.62 for benzene, 0.50 for nitric acid, 0.13 for methane and 0.56 for chlorine. The petitioner applies the lowest degree of functionality (n = 2.0) to show that more than 20 % of the substance is derived from taxable chemicals and the midpoint degree (n = 2.5) to calculate the rate for the full range.
The petition identifies the predominant production method as the reaction of aniline and formaldehyde to produce methylenedianiline, followed by phosgene treatment, and includes a stoichiometric material consumption equation. Filing dates are July 1, 2024 for purposes of Rev. Proc. 2022-26 and November 21, 2025 for purposes of making a determination. The public docket number is IRS-2026-1028.
Written comments and requests for a public hearing must be received on or before October 26, 2026. Submissions may be made electronically via the Federal eRulemaking Portal at regulations.gov, referencing docket IRS-2026-1028, or mailed to the IRS address in Washington, DC. All comments become part of the public record and will be posted without change.
The notice emphasizes that publication of the petition does not constitute a determination that the list of taxable substances is modified; the IRS will consider the comments before any final action.
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