Sec. 4218 Use by manufacturer or importer considered sale
(a) General rule. If any person manufactures, produces, or imports an article (other than a tire taxable under section 4071) and uses it (otherwise than as material in the manufacture or production of, or as a component part of, another article taxable under this chapter to be manufactured or produced by him), then he shall be liable for tax under this chapter in the same manner as if such article were sold by him. This subsection shall not apply in the case of gasoline used by any person, for nonfuel purposes, as a material in the manufacture or production of another article to be manufactured or produced by him. For the purpose of applying the first sentence of this subsection to coal taxable under section 4121, the words "(otherwise than as material in the manufacture or production of, or as a component part of, another article taxable under this chapter to be manufactured or produced by him)" shall be disregarded.
(b) Tires. If any person manufactures, produces, or imports a tire taxable under section 4071, and sells it on or in connection with the sale of any article, or uses it, then he shall be liable for tax under this chapter in the same manner as if such article were sold by him.
(c) Computation of tax. Except as provided in section 4223(b), in any case in which a person is made liable for tax by the preceding provisions of this section, the tax (if based on the price for which the article is sold) shall be computed on the price at which such or similar articles are sold, in the ordinary course of trade, by manufacturers, producers, or importers, thereof, as determined by the Secretary.