(1) Taxable carbon substance The term taxable carbon substance means— (A) coal (including lignite and peat), (B) petroleum and any petroleum product (as defined in section 4612(a)(3)), and (C) natural gas, which is extracted, manufactured, or produced in the United States or entered into the United States for consumption, use, or warehousing. (2) United States The term United States has the meaning given such term by section 4612(a)(4). (3) Importer The term importer means the person entering the taxable carbon substance for consumption, use, or warehousing. (4) Ton The term ton means metric tons. In the case of any taxable carbon substance which is a gas, the term ton means the amount of such gas in cubic feet which is the equivalent of a metric ton on a molecular weight basis. (5) Carbon-intensive good The term carbon-intensive good means a good that (as identified by the Secretary by rule)— (A) is a primary product, or (B) is a manufactured item in which one or more primary products are inputs and the cost of production of which in the United States is significantly increased by this subchapter. (6) Primary product The term primary product means— (A) iron, steel, steel mill products (including pipe and tube), aluminum, cement, glass (including flat, container, and specialty glass and fiberglass), pulp, paper, chemicals, or industrial ceramics, and (B) any other manufactured product that the Secretary determines— (i) is sold for purposes of further manufacture, and (ii) generates, in the course of the manufacture of the product, direct and indirect carbon-dioxide emissions that are comparable (on an emissions-per-dollar of output basis) to emissions generated in the manufacture or production of primary products identified in subparagraph (A). (7) Equivalent measure The term equivalent measure means a tax or other regulatory requirement that imposes a cost on manufacturers of carbon intensive goods located outside the United States approximately equal to the cost imposed by section 4691 on manufacturers of