---identifier: "/us/cfr/t40/s421.271"source: "ecfr"legal_status: "authoritative_unofficial"title: "40 CFR § 421.271 - Specialized definitions."title_number: 40title_name: "Protection of Environment"section_number: "421.271"section_name: "Specialized definitions."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/s421.271
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.
# 421.271 Specialized definitions.In addition to what is provided below:(a) The general definitions, abbreviations, and methods of analysis set forth in 40 CFR part 401 shall apply to this subpart.(b) The term *rare earth metals* refers to the elements scandium, yttrium, and lanthanum to lutetium, inclusive.(c) The term *mischmetal* refers to a rare earth metal alloy comprised of the natural mixture of rare earths to about 94-99 percent. The balance of tha alloy includes traces of other elements and one to two percent iron.