((a)) ** General rule** There is hereby imposed a tax on any taxable substance sold or used by the importer thereof.

((b)) ** Amount of tax**

((1)) ** In general** Except as provided in paragraph (2), the amount of the tax imposed by subsection (a) with respect to any taxable substance shall be the amount of the tax which would have been imposed by section 4661 on the taxable chemicals used as materials in the manufacture or production of such substance if such taxable chemicals had been sold in the United States for use in the manufacture or production of such taxable substance.

((2)) ** Rate where importer does not furnish information to Secretary** If the importer does not furnish to the Secretary (at such time and in such manner as the Secretary shall prescribe) sufficient information to determine under paragraph (1) the amount of the tax imposed by subsection (a) on any taxable substance, the amount of the tax imposed on such taxable substance shall be 10 percent of the appraised value of such substance as of the time such substance was entered into the United States for consumption, use, or warehousing.

((3)) ** Authority to prescribe rate in lieu of paragraph (2) rate** The Secretary may prescribe for each taxable substance a tax which, if prescribed, shall apply in lieu of the tax specified in paragraph (2) with respect to such substance. The tax prescribed by the Secretary shall be equal to the amount of tax which would be imposed by subsection (a) with respect to the taxable substance if such substance were produced using the predominant method of production of such substance.

((c)) ** Exemptions for substances taxed under sections 4611 and 4661** No tax shall be imposed by this section on the sale or use of any substance if tax is imposed on such sale or use under section 4611 or 4661.

((d)) ** Tax-free sales, etc. for substances used as certain fuels or in the production of fertilizer or animal feed** Rules similar to the following rules shall apply for purposes of applying this section with respect to taxable substances used or sold for use as described in such rules:

((1)) Paragraphs (2), (5), and (9) of section 4662(b) (relating to tax-free sales of chemicals used as fuel or in the production of fertilizer or animal feed).

((2)) Paragraphs (2), (3), and (4) of section 4662(d) (relating to refund or credit of tax on certain chemicals used as fuel or in the production of fertilizer or animal feed).

((e)) ** Termination** No tax shall be imposed by this section after .December 31, 20312031-12-31