# 2025-09133: IRS May Tax a Chemical With a Name Built for Scrabble

2025-09133, Superfund Tax on Chemical Substances; Request To Modify List of Taxable Substances; Notice of Filing for Tri-lsoNonyl Tri-Mellitate, is a Federal Register notice from Treasury Department, Internal Revenue Service published 2025-05-21, effective Written comments and requests for a public hearing must be received on or before July 21, 2025.; PRIA reads it as touching household money (as of 2026-10-22).

- Canonical: https://policyrisk.com/federal-register/2025-09133
- As of: 2026-10-22
- Plain-text twin of the page above; the HTML and this file carry the same facts.

## Facts
- Document number: 2025-09133
- Title: Superfund Tax on Chemical Substances; Request To Modify List of Taxable Substances; Notice of Filing for Tri-lsoNonyl Tri-Mellitate
- Type: Notice
- Agencies: Treasury Department; Internal Revenue Service
- Citation: 90 FR 21827
- Published: 2025-05-21
- Effective: Written comments and requests for a public hearing must be received on or before July 21, 2025.
- Comments close: not stated
- Significant: no
- Touches household money: yes
- Regulation identifier numbers: none
- Last updated: 2026-10-22

## In one line

IRS May Tax a Chemical With a Name Built for Scrabble

## Summary

The IRS got a request to add a new chemical, tri-isononyl tri-mellitate, to the list of substances that get a Superfund tax. This means companies dealing with this chemical might pay extra taxes if it’s added. People have until July 21, 2025, to share their thoughts or ask for a public hearing before any decision is made.

## Abstract

This notice of filing announces that a petition has been filed requesting that tri-isononyl tri-mellitate be added to the list of taxable substances. This notice of filing also requests comments on the petition. This notice of filing is not a determination that the list of taxable substances is modified.

## Effects PRIA read

- Petition to Add Chemical to Taxable List: cost, low. A petition was filed asking that tri-isononyl tri-mellitate be added to the list of substances taxable under Internal Revenue Code section 4672(a). If the substance is added to that list, entities producing, importing, or exporting it would be treated as dealing with a listed taxable chemical under…
- Petitioner-Reported Per-Ton Tax Estimate: cost, low. The petitioner calculated a Superfund tax rate for tri-isononyl tri-mellitate of $5.06 per ton based on the petitioner’s conversion factors. This $5.06/ton figure is the petitioner’s calculation and was submitted as part of the petition.
- Petitioner Reports 47.3% Taxable Share by Weight: cost, low. The petition states that taxable chemicals constitute 47.3 percent by weight of the materials used to produce tri-isononyl tri-mellitate. That 47.3% figure was provided by the petitioner as part of the information used to calculate tax treatment.
- Proposed HTSUS/Schedule B/CAS Classification: cost, low. The petitioner proposed classification numbers for tri-isononyl tri-mellitate: HTSUS 2917.39.20.00, Schedule B 2917.39.2000, and CAS number 53894-23-8. These classification identifiers were submitted as part of the petition to define the substance for regulatory and trade classification purposes.

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## Sources
- [2025-09133 on federalregister.gov](https://www.federalregister.gov/documents/2025/05/21/2025-09133/superfund-tax-on-chemical-substances-request-to-modify-list-of-taxable-substances-notice-of-filing)
- [2025-09133 as published (PDF)](https://www.govinfo.gov/content/pkg/FR-2025-05-21/pdf/2025-09133.pdf)

## Related
- [Previous: 2025-09132, Superfund Tax on Chemical Substances; Request To Modify List of Taxable Substan…](https://policyrisk.com/federal-register/2025-09132)
- [Next: 2025-09134, Superfund Tax on Chemical Substances; Request To Modify List of Taxable Substan…](https://policyrisk.com/federal-register/2025-09134)
- [All Federal Register documents](https://policyrisk.com/federal-register)

Source: PRIA, https://policyrisk.com/federal-register/2025-09133 (as of 2026-10-22).