40 CFR § 421.294 - Standards of performance for new sources.
---
identifier: "/us/cfr/t40/s421.294"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "40 CFR § 421.294 - Standards of performance for new sources."
title_number: 40
title_name: "Protection of Environment"
section_number: "421.294"
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"
---
# 421.294 Standards of performance for new sources.
Any new source subject to this subpart shall achieve the following new source performance standards:
(a) Tin smelter SO<sub>2</sub> scrubber.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of crude tapped tin produced | |
| Arsenic | 12.790 | 5.703 |
| Lead | 2.575 | 1.196 |
| Iron | 11.040 | 5.611 |
| Tin | 3.495 | 2.024 |
| Total suspended solids | 138.000 | 110.400 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(b) Dealuminizing rinse.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of dealuminized scrap produced | |
| Lead | 0.010 | 0.005 |
| Cyanide (total) | 0.007 | 0.003 |
| Fluoride | 1.225 | 0.697 |
| Tin | 0.013 | 0.008 |
| Total suspended solids | 0.525 | 0.420 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(c) Tin mud acid neutralization filtrate.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of neutralized dewatered tin mud produced | |
| Lead | 1.413 | 0.656 |
| Cyanide (total) | 1.009 | 0.404 |
| Fluoride | 176.600 | 100.400 |
| Tin | 1.918 | 1.110 |
| Total suspended solids | 75.710 | 60.560 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(d) Tin hydroxide wash.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of tin hydroxide washed | |
| Lead | 3.347 | 1.554 |
| Cyanide (total) | 2.391 | 0.956 |
| Fluoride | 418.400 | 237.900 |
| Tin | 4.542 | 2.630 |
| Total suspended solids | 179.300 | 143.400 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(e) Spent electrowinning solution from new scrap.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of cathode tin produced | |
| Lead | 4.704 | 2.184 |
| Cyanide (total) | 3.360 | 1.344 |
| Fluoride | 588.000 | 334.300 |
| Tin | 6.384 | 3.696 |
| Total suspended solids | 252.000 | 201.600 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(f) Spent electrowinning solution from municipal solid waste.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of MSW scrap used as raw material | |
| Lead | 0.033 | 0.015 |
| Cyanide (total) | 0.024 | 0.010 |
| Fluoride | 4.165 | 2.368 |
| Tin | 0.045 | 0.026 |
| Total suspended solids | 1.785 | 1.428 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(g) Tin hydroxide supernatant from scrap.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of tin metal recovered from scrap | |
| Lead | 15.580 | 7.233 |
| Cyanide (total) | 11.130 | 4.451 |
| Fluoride | 1,947.000 | 1,107.000 |
| Tin | 21.140 | 12.240 |
| Total suspended solids | 834.600 | 667.700 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(h) Tin hydroxide supernatant from plating solutions and sludges.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of tin metal recovered from plating solutions and sludges | |
| Lead | 32.20 | 14.95 |
| Cyanide (total) | 23.00 | 9.20 |
| Fluoride | 4,025.00 | 2,289.00 |
| Tin | 43.70 | 25.30 |
| Total suspended solids | 1,725.00 | 1,380.00 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |
(i) Tin hydroxide filtrate.
NSPS for the Secondary Tin Subcategory
| Pollutant or pollutant property | Maximum for any 1 day | Maximum for monthly average |
| --- | --- | --- |
| | mg/kg (pounds per million pounds) of tin metal produced | |
| Lead | 7.012 | 3.256 |
| Cyanide (total) | 5.009 | 2.004 |
| Fluoride | 876.500 | 498.400 |
| Tin | 9.517 | 5.510 |
| Total suspended solids | 375.700 | 300.500 |
| pH | () | () |
| Within the range of 7.5 to 10.0 at all times. | | |