40 CFR § 421.274 - Standards of performance for new sources.
---
identifier: "/us/cfr/t40/s421.274"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 421.274 - Standards of performance for new sources."
title_number: 40
title_name: "Protection of Environment"
section_number: "421.274"
section_name: "Standards of performance for new sources."
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: false
currency: "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"
---
# 421.274 Standards of performance for new sources.
Any new source subject to this subpart shall achieve the following new source performance standards:
(a) Dryer Vent Water Quench and Scrubber.
NSPS for the Primary Rare Earth Metals Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of mischmetal produced from wet rare earth chlorides | |
| Hexachlorobenzene | 0.042 | 0.042 |
| Chromium (total) | 1.544 | 0.626 |
| Lead | 1.168 | 0.542 |
| Nickel | 2.295 | 1.544 |
| Total suspended solids | 62.600 | 50.080 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(b) Dryer vent caustic wet air pollution control.
NSPS for the Primary Rare Earth Metals Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of mischmetal produced from wet rare earth chlorides | |
| Hexachlorobenzene | 0.007 | 0.007 |
| Chromium (total) | 0.272 | 0.110 |
| Lead | 0.206 | 0.095 |
| Nickel | 0.404 | 0.272 |
| Total suspended solids | 11.010 | 8.808 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(c) Electrolytic cell water quench and scrubber.
NSPS for the Primary Rare Earth Metals Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of total mischmetal produced | |
| Hexachlorobenzene | 0.094 | 0.094 |
| Chromium (total) | 3.474 | 1.409 |
| Lead | 2.629 | 1.221 |
| Nickel | 5.165 | 3.474 |
| Total suspended solids | 140.900 | 112.700 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(d) Electrolytic cell caustic wet air pollution control.
NSPS for the Primary Rare Earth Metals Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of total mischmetal produced | |
| Hexachlorobenzene | 0.000 | 0.000 |
| Chromium (total) | 0.000 | 0.000 |
| Lead | 0.000 | 0.000 |
| Nickel | 0.000 | 0.000 |
| Total suspended solids | 0.000 | 0.000 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(e) Sodium hypochlorite filter backwash.
NSPS for the Primary Rare Earth Metals Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of total mischmetal produced | |
| Hexachlorobenzene | 0.004 | 0.004 |
| Chromium (total) | 0.134 | 0.054 |
| Lead | 0.101 | 0.047 |
| Nickel | 0.199 | 0.134 |
| Total suspended solids | 5.430 | 4.334 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |