40 CFR § 421.90 - Applicability: Description of the metallurgical acid plants subcategory.
---identifier: "/us/cfr/t40/s421.90"source: "ecfr"legal_status: "authoritative_unofficial"title: "40 CFR § 421.90 - Applicability: Description of the metallurgical acid plants subcategory."title_number: 40title_name: "Protection of Environment"section_number: "421.90"section_name: "Applicability: Description of the metallurgical acid plants subcategory."chapter_name: "ENVIRONMENTAL PROTECTION AGENCY"subchapter_number: "N"subchapter_name: "EFFLUENT GUIDELINES AND STANDARDS"part_number: "421"part_name: "NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY"positive_law: falsecurrency: "2026-03-24"last_updated: "2026-03-24"format_version: "1.1.0"generator: "[email protected]"authority: "Secs. 301, 304 (b), (c), (e), and (g), 306 (b) and (c), 307 (b) and (c), 308 and 501 of the Clean Water Act (the Federal Water Pollution Control Act Amendments of 1972, as amended by the Clean Water Act of 1977) and the Water Quality Act of 1987 (the “Act”); 33 U.S.C. 1311, 1314 (b), (c), (e), and (g), 1316 (b) and (c), 1317 (b) and (c), 1318 and 1361; 86 Stat. 816, Pub. L. 92-500; 91 Stat. 1567, Pub. L. 95-217; 101 Stat. 7, Pub. L. 100-4."regulatory_source: "49 FR 8790, Mar. 8, 1984, unless otherwise noted."cfr_part: "421"---
Identifier
/us/cfr/t40/s421.90
Currency
2026-03-24
Positive Law
No
Updated
2026-03-24
Chapter
Environmental Protection Agency
Authority
Secs. 301, 304 (b), (c), (e), and (g), 306 (b) and (c), 307 (b) and (c), 308 and 501 of the Clean Water Act (the Federal Water Pollution Control Act Amendments of 1972, as amended by the Clean Water A... Secs. 301, 304 (b), (c), (e), and (g), 306 (b) and (c), 307 (b) and (c), 308 and 501 of the Clean Water Act (the Federal Water Pollution Control Act Amendments of 1972, as amended by the Clean Water Act of 1977) and the Water Quality Act of 1987 (the “Act”); 33 U.S.C. 1311, 1314 (b), (c), (e), and (g), 1316 (b) and (c), 1317 (b) and (c), 1318 and 1361; 86 Stat. 816, Pub. L. 92-500; 91 Stat. 1567, Pub. L. 95-217; 101 Stat. 7, Pub. L. 100-4.
# 421.90 Applicability: Description of the metallurgical acid plants subcategory.The provisions of this subpart apply to process wastewater discharges resulting from or associated with the manufacture of by-product sulfuric acid at primary copper smelters, primary zinc facilities, primary lead facilities, and primary molybdenum facilities, including any associated air pollution control or gas-conditioning systems for sulfur dioxide off-gases from pyrometallurgical operations.[49 FR 8811, Mar. 8, 1984, as amended at 50 FR 38342, Sept. 20, 1985]