# § 4672. Definitions and special rules
**(a)** **Taxable substance** For purposes of this subchapter—
**(1)** **In general** The term “taxable substance” means any substance which, at the time of sale or use by the importer, is listed as a taxable substance by the Secretary for purposes of this subchapter.
**(2)** **Determination of substances on list** A substance shall be listed under paragraph (1) if—
If an importer or exporter of any substance requests that the Secretary determine whether such substance be listed as a taxable substance under paragraph (1) or be removed from such listing, the Secretary shall make such determination within 180 days after the date the request was filed.
**(A)** the substance is contained in the list under paragraph (3), or
**(B)** the Secretary determines, in consultation with the Administrator of the Environmental Protection Agency and the Commissioner of U.S. Customs and Border Protection, that taxable chemicals constitute more than 20 percent of the weight (or more than 20 percent of the value) of the materials used to produce such substance (determined on the basis of the predominant method of production).
**(3)** **Initial list of taxable substances**
| | |
| --- | --- |
| Cumene | Methylene chloride |
| Styrene | Polypropylene |
| Ammonium nitrate | Propylene glycol |
| Nickel oxide | Formaldehyde |
| Isopropyl alcohol | Acetone |
| Ethylene glycol | Acrylonitrile |
| Vinyl chloride | Methanol |
| Polyethylene resins, total | Propylene oxide |
| Polybutadiene | Polypropylene resins |
| Styrene-butadiene, latex | Ethylene oxide |
| Styrene-butadiene, snpf | Ethylene dichloride |
| Synthetic rubber, not containing fillers | Cyclohexane |
| Urea | Isophthalic acid |
| Ferronickel | Maleic anhydride |
| Ferrochromium nov 3 pct | Phthalic anhydride |
| Ferrochrome ov 3 pct. carbon | Ethyl methyl ketone |
| Unwrought nickel | Chloroform |
| Nickel waste and scrap | Carbon tetrachloride |
| Wrought nickel rods and wire | Chromic acid |
| Nickel powders | Hydrogen peroxide |
| Phenolic resins | Polystyrene homopolymer resins |
| Polyvinylchloride resins | Melamine |
| Polystyrene resins and copolymers | Acrylic and methacrylic acid resins |
| Ethyl alcohol for nonbeverage use | Vinyl resins |
| Ethylbenzene | Vinyl resins, NSPF. |
**(4)** **Modifications to list** The Secretary shall add to the list under paragraph (3) substances which meet either the weight or value tests of paragraph (2)(B) and may remove from such list only substances which meet neither of such tests.
**(b)** **Other definitions** For purposes of this subchapter—
**(1)** **Importer** The term “importer” means the person entering the taxable substance for consumption, use, or warehousing.
**(2)** **Taxable chemicals; United States** The terms “taxable chemical” and “United States” have the respective meanings given such terms by section 4662(a).
**(c)** **Disposition of revenues from Puerto Rico and the Virgin Islands** The provisions of subsections (a)(3) and (b)(3) of section 7652 shall not apply to any tax imposed by section 4671.
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**Source Credit**: (Added Pub. L. 99–499, title V, § 515(a), Oct. 17, 1986, 100 Stat. 1768; amended Pub. L. 100–647, title II, § 2001(b), Nov. 10, 1988, 102 Stat. 3594; Pub. L. 114–125, title VIII, § 802(d)(2), Feb. 24, 2016, 130 Stat. 210; Pub. L. 117–58, div. H, title II, § 80201(c)(1), Nov. 15, 2021, 135 Stat. 1330.)
## Editorial Notes
### Amendments
2021—Subsec. (a)(2)(B). substituted “20 percent” for “50 percent” in two places.
1988—Subsec. (a)(2). , inserted at end “If an importer or exporter of any substance requests that the Secretary determine whether such substance be listed as a taxable substance under paragraph (1) or be removed from such listing, the Secretary shall make such determination within 180 days after the date the request was filed.”
Subsec. (a)(2)(B). , inserted “(or more than 50 percent of the value)” after “weight”.
Subsec. (a)(4). , amended par. (4) generally. Prior to amendment, par. (4) read as follows:
“(A) .—The Secretary may add substances to or remove substances from the list under paragraph (3) (including items listed by reason of paragraph (2)) as necessary to carry out the purposes of this subchapter.
“(B) .—The Secretary may, to the extent necessary to carry out the purposes of this subchapter, add any substance to the list under paragraph (3) if such substance would be described in paragraph (2)(B) if ‘value’ were substituted for ‘weight’ therein.”
## Statutory Notes and Related Subsidiaries
### Change of Name
“Commissioner of U.S. Customs and Border Protection” substituted for “Commissioner of Customs” in subsec. (a)(2)(B) on authority of , set out as a note under , Domestic Security.
### Effective Date of 2021 Amendment
Amendment by effective , see , set out as a note under .
### Effective Date of 1988 Amendment
Amendment by effective, except as otherwise provided, as if included in the provision of the Superfund Revenue Act of 1986, , to which it relates, see , set out as a note under .
### Effective Date
Section effective , see , set out as a note under .
### Transfer of Functions
For transfer of functions, personnel, assets, and liabilities of the United States Customs Service of the Department of the Treasury, including functions of the Secretary of the Treasury relating thereto, to the Secretary of Homeland Security, and for treatment of related references, see sections 203(1), 551(d), 552(d), and 557 of Title 6, Domestic Security, and the Department of Homeland Security Reorganization Plan of , as modified, set out as a note under . For establishment of U.S. Customs and Border Protection in the Department of Homeland Security, treated as if included in as of , see , as amended generally by , and , set out as a note under .
### Presumption As a Taxable Substance for Prior Determinations
> “Except as otherwise determined by the Secretary of the Treasury (or the Secretary’s delegate), any substance which was determined to be a taxable substance by reason of section 4672(a)(2) of the Internal Revenue Code of 1986 prior to the date of enactment of this Act [
>
> ] shall continue to be treated as a taxable substance for purposes of such section after such date.”
, , , provided that:
### Publication of Initial List
> “Not later than
>
> , the Secretary of the Treasury (or the Secretary’s delegate) shall publish an initial list of taxable substances under section 4672(a) of the Internal Revenue Code of 1986.”
, , , provided that: