unmanufactured articles, materials, and supplies that have been mined or produced in the United States; and

manufactured articles, materials, and supplies that have been manufactured in the United States substantially all from articles, materials, or supplies mined, produced, or manufactured in the United States.

If the head of the Federal agency making the contract finds that it is impracticable to comply with subsection (a) for a particular article, material, or supply or that it would unreasonably increase the cost, an exception shall be noted in the specifications for that article, material, or supply and a public record of the findings that justified the exception shall be made.

Subsection (a) shall be regarded as requiring the purchase, for public use within the United States, of articles, materials, or supplies manufactured in the United States in sufficient and reasonably available commercial quantities and of a satisfactory quality, unless the head of the Federal agency concerned determines their acquisition to be inconsistent with the public interest, their cost to be unreasonable, or that the articles, materials, or supplies of the class or kind to be used, or the articles, materials, or supplies from which they are manufactured, are not mined, produced, or manufactured in the United States in sufficient and reasonably available commercial quantities and of a satisfactory quality.

For purposes of this section, manufactured articles, materials, and supplies of iron and steel are deemed manufactured in the United States only if all manufacturing processes involved in the production of such iron and steel, from the initial melting stage through the application of coatings, occurs in the United States.

Notwithstanding any law or regulation to the contrary, including section 1907 of this title and the Federal Acquisition Regulation, the requirements of this section apply to all iron and steel articles, materials, and supplies used in contracts described in subsection (a).