This industry group comprises establishments primarily engaged in smelting iron ore and steel scrap to produce pig iron in molten or solid form; converting pig iron into steel by the removal, through combustion in furnaces, of the carbon in the iron. These establishments may cast ingots only, or also produce iron and steel basic shapes, such as plates, sheets, strips, rods and bars, and other fabricated products. Electric arc furnace mini-mills are included. Establishments primarily engaged in producing ferro-alloys are also included.

This industry group comprises establishments primarily engaged in manufacturing iron and steel pipe and tube, drawing steel wire, and rolling steel shapes, from purchased steel.

This industry group comprises establishments primarily engaged in extracting alumina generally from bauxite ore; producing aluminum from alumina; refining aluminum by any process; and rolling, drawing, casting, extruding and alloying aluminum and aluminum-based alloy basic shapes.

This industry group comprises establishments primarily engaged in smelting, refining, rolling, drawing, extruding and alloying non-ferrous metal, except aluminum.

This industry group comprises establishments primarily engaged in pouring molten metal into moulds or dies to form castings.