Section NR 256.40 - Applicability; description of the zinc casting subcategory(1) This subchapter applies to discharges to waters of the state and to introductions of pollutants into publicly owned treatment works from zinc casting operations. It applies to a production process if the molten metal contains, on average, greater than 50% by weight of zinc or if zinc comprises the greatest percentage of the metal, measured by weight.(2) This subchapter does not apply to the casting of ingots, pigs or other cast shapes following primary metal smelting, which is regulated by the nonferrous metals manufacturing point source category under 40 CFR Part 421 . This subchapter does not apply to the casting of zinc performed as an integral part of zinc forming and conducted on-site at a zinc forming plant, which is regulated by the nonferrous metals forming point source category under 40 CFR Part 471.(3) Processing operations following the cooling of castings, except for grinding scrubber operations, may be regulated by nonferrous metals forming point source category under 40 CFR Part 471, electroplating point source category under ch. NR 260, or metal finishing point source category under ch. NR 261.Wis. Admin. Code Department of Natural Resources NR 256.40
Cr. Register, June, 1989, No. 402, eff. 7-1-89,