26 U.S.C. § 4672

1. (a)For purposes of this subchapter—
   1. (1)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. (2)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.
      1. (A)the substance is contained in the list under paragraph (3), or
      2. (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. (3)CumeneMethylene chloride StyrenePolypropylene Ammonium nitratePropylene glycol Nickel oxideFormaldehyde Isopropyl alcoholAcetone Ethylene glycolAcrylonitrile Vinyl chlorideMethanol Polyethylene resins, totalPropylene oxide PolybutadienePolypropylene resins Styrene-butadiene, latexEthylene oxide Styrene-butadiene, snpfEthylene dichloride Synthetic rubber, not containing fillersCyclohexane UreaIsophthalic acid FerronickelMaleic anhydride Ferrochromium nov 3 pctPhthalic anhydride Ferrochrome ov 3 pct. carbonEthyl methyl ketone Unwrought nickelChloroform Nickel waste and scrapCarbon tetrachloride Wrought nickel rods and wireChromic acid Nickel powdersHydrogen peroxide Phenolic resinsPolystyrene homo­polymer resins Polyvinylchloride resinsMelamine Polystyrene resins and copolymersAcrylic and methacrylic acid resins Ethyl alcohol for nonbeverage useVinyl resins EthylbenzeneVinyl resins, NSPF.
   4. (4)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.
2. (b)For purposes of this subchapter—
   1. (1)The term “importer” means the person entering the taxable substance for consumption, use, or warehousing.
   2. (2)The terms “taxable chemical” and “United States” have the respective meanings given such terms by section 4662(a).
3. (c)The provisions of subsections (a)(3) and (b)(3) of section 7652 shall not apply to any tax imposed by section 4671.