40 CFR § 421.234 - Standards of performance for new sources.

---
identifier: "/us/cfr/t40/s421.234"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 421.234 - Standards of performance for new sources."
title_number: 40
title_name: "Protection of Environment"
section_number: "421.234"
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"
---


# 421.234 Standards of performance for new sources.

Any new source subject to this subpart shall achieve the following new source performance standards:

(a) Raw Material Dust Control.

NSPS for the Primary Nickel and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of copper, nickel, and cobalt in the crushed raw material |  |
| Copper | 0.099 | 0.047 |
| Nickel | 0.042 | 0.028 |
| Ammonia (as N) | 10.260 | 4.512 |
| Cobalt | 0.011 | 0.005 |
| Total suspended solids | 1.155 | 0.924 |
| pH |  |  |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(b) Nickel wash water.

NSPS for the Primary Nickel and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of nickel powder washed |  |
| Copper | 0.043 | 0.021 |
| Nickel | 0.019 | 0.013 |
| Ammonia (as N) | 4.515 | 1.985 |
| Cobalt | 0.005 | 0.002 |
| Total suspended solids | 0.508 | 0.406 |
| pH |  |  |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(c) Nickel reduction decant.

NSPS for the Primary Nickel and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of nickel produced |  |
| Copper | 16.250 | 7.744 |
| Nickel | 6.982 | 4.697 |
| Ammonia (as N) | 1,692.000 | 743.900 |
| Cobalt | 1.777 | 0.889 |
| Total suspended solids | 190.400 | 152.300 |
| pH |  |  |
| Within the range of 7.5 to 10.0 at all times. |  |  |

(d) Cobalt reduction decant.

NSPS for the Primary Nickel and Cobalt Subcategory

| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
|  | mg/kg (pounds per million pounds) of cobalt produced |  |
| Copper | 27.390 | 13.050 |
| Nickel | 11.770 | 7.917 |
| Ammonia (as N) | 2,852.000 | 1,254.000 |
| Cobalt | 2.996 | 1.498 |
| Total suspended solids | 321.000 | 256.800 |
| pH |  |  |
| Within the range of 7.5 to 10.0 at all times. |  |  |