The IRS recently added 21 new chemicals to the List of taxable substances subject to the Superfund Chemical Excise Taxes and corrected a typographical error in guidance on the spelling of sodium nitrilotriacetate monohydrate and prescribed a tax rate of $3.97 per ton for the substance, effective July 1, 2022.
The Superfund Chemical Excise Taxes apply to manufacturers, producers or importers who sell or use "taxable chemicals" or "taxable substances" that are manufactured or produced in the U.S. or are imported into the United States. The tax is applicable if the chemicals or substances are considered taxable under §4661 or §4672 of the Internal Revenue Code ("Code"). Businesses must analyze the chemical composition of all of their products and determine where along the supply chain any taxable chemicals or substances are imported into, or produced the U.S., and by whom.
The following substances were added to the List according to the Notice published in the Federal Register on August 4, 2025:
Polyphenylene sulfide
Cellulose acetate (degree of substitution = 1.5–2.0)
4,4′- isopropylidenediphenol-epichlorohydrin copolymer
Nylon 6
Caprolactam
Methyl ethyl ketoxime
Iso-butanol
Diethylene glycol
Monomethyl ether
Ethylene glycol phenyl ether
Methoxytriglycol
Propylene glycol methyl ether acetate
Propylene glycol methyl ether
Propylene glycol n-propyl ether
Propylene glycol phenyl ether
Di-isobutyl carbinol
Di-isobutyl ketone
Methyl isobutyl carbinol
Cyanuric acid
Potassium bicarbonate
Potassium carbonate
Sodium chlorite.
The effective date for purposes of the excise tax under §4671 of the Code for the taxable substances added to the list is January 1, 2026.
The updated List and prescribed tax rates for taxable substances will be included in the instructions to IRS Form 6627, Environmental Taxes.
In November 2021, President Biden signed into law the Infrastructure Investment and Jobs Act, which revived and expanded long dormant excise taxes (known as the Superfund Chemicals Taxes) used to address hazardous waste sites in the United States. The new taxes, which went into effect on July 1, 2022, apply to the sale of certain chemical substances, and to an importer's sale or use of specified substances.
The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.
