{"data":{"id":"us/40-cfr-421.24","jurisdiction":"us","citation":"40 CFR 421.24","heading":"Standards of performance for new sources.","body":"Any new source subject to this subpart shall achieve the following new source performance standards:\n(a) Subpart B—Anode and Cathode Paste Plant Wet Air.\nPollution Control—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of paste produced\nBenzo(a)pyrene .000\nAntimony .000 .000\nNickel .000 .000\nAluminum .000 .000\nFluoride .000 .000\nOil and grease .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(b) Subpart B—Anode Contact Cooling and Briquette Quenching.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of anodes cast\nBenzo(a)pyrene 0.007 0.003\nAntimony .403 .180\nNickel .115 .077\nAluminum 1.277 .566\nFluoride 12.440 5.518\nOil and grease 2.090 2.090\nTotal suspended solids 3.135 2.508\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(c) Subpart B—Anode Bake Plant Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of anodes baked\nBenzo(a)pyrene .000\nAntimony .000 .000\nNickel .000 .000\nAluminum .000 .000\nFluoride .000 .000\nOil and grease .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(d) Subpart B—Cathode Reprocessing (Operated With Dry Potline Scrubbing and Not Commingled With Other Process or Nonprocess Waters).\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of cryolite recovered\nBenzo(a)pyrene 1.181 0.547\nAntimony 420.400 189.200\nCyanide 157.600 70.060\nNickel 80.570 35.030\nAluminum 273.200 122.600\nFluoride 29,430.000 13,310.000\nOil and grease 350.300 350.300\nTotal suspended solids 2,172.000 945.800\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(e) Subpart B—Cathode Reprocessing (Operated With Dry Potline Scrubbing and Commingled With Other Process or Nonprocess Waters).\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of cryolite recovered\nBenzo(a)pyrene 1.181 0.547\nAntimony 67.610 30.120\nCyanide 157.600 70.060\nNickel 19.270 12.960\nAluminum 214.000 94.930\nFluoride 2,084.000 924.800\nOil and grease 350.300 350.300\nTotal suspended solids 2,172.000 945.800\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(f) Subpart B—Potline Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of aluminum produced from electrolytic reduction\nBenzo(a)pyrene .000\nAntimony .000 .000\nNickel .000 .000\nAluminum .000 .000\nFluoride .000 .000\nOil and grease .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(g) Subpart B—Potroom Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of aluminum produced from electrolytic reduction\nBenzo(a)pyrene .000\nAntimony .000 .000\nNickel .000 .000\nAluminum .000 .000\nFluoride .000 .000\nOil and grease .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(h) Subpart B—Potline SO2 Emissions Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) aluminum produced from electrolytic reduction\nBenzo(a)pyrene 0.045 0.021\nAntimony 2.588 1.153\nNickel .738 .496\nAluminum 8.194 3.634\nFluoride 79.790 35.400\nOil and grease 13.410 13.410\nTotal suspended solids 20.120 16.090\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(i) Subpart B—Degassing Wet Air Pollution Control.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of aluminum produced from electrolytic reduction\nBenzo(a)pyrene .000\nAntimony .000 .000\nNickel .000 .000\nAluminum .000 .000\nFluoride .000 .000\nOil and grease .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(j) Subpart B—Pot Repair and Pot Soaking.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of aluminum produced from electrolytic reduction\nBenzo(a)pyrene .000\nAntimony .000 .000\nNickel .000 .000\nAluminum .000 .000\nFluoride .000 .000\nOil and grease .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.\n(k) Subpart B—Direct Chill Casting Contact Cooling.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of aluminum product from direct chill casting\nBenzo(a)pyrene (1) (1)\nAntimony 2.565 1.143\nNickel .731 .492\nAluminum 8.120 3.602\nFluoride 79.080 35.090\nOil and grease 13.290 13.290\nTotal suspended solids 19.940 15.950\npH (2) (2)\n1 There shall be no discharge allowance for this pollutant.\n2 The pH shall be maintained within the range of 7.0 to 10.0 at all times except for those situations when this waste is discharged separately and without commingling with any other waste-water in which case the pH shall be within the range of 6.0 to 10.0 at all times.\n(l) Subpart B—Continuous Rod Casting Contact Cooling.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pound per million pounds) of aluminum product from rod casting\nBenzo(a)pyrene (1) (1)\nAntimony .201 .089\nNickel .057 .038\nAluminum .636 .282\nFluoride 6.188 2.746\nOil and grease 1.040 1.040\nTotal suspended solids 1.560 1.248\npH (2) (2)\n1 There shall be no discharge allowance for this pollutant.\n2 Within the range of 7.0 to 10.0 at all times.\n(m) Subpart B—Stationary Casting or Shot Casting Contact Cooling.\nNSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/kg (pounds per million pounds) of aluminum product from stationary casting or shot casting\nBenzo(a)pyrene .000\nAntimony .000 .000\nNickel .000 .000\nAluminum .000 .000\nFluoride .000 .000\nOil and grease .000 .000\nTotal suspended solids .000 .000\npH (1) (1)\n1 Within the range of 7.0 to 10.0 at all times.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS","PART 421—NONFERROUS METALS MANUFACTURING POINT SOURCE CATEGORY","Subpart B—Primary Aluminum Smelting Subcategory"],"source_url":"https://www.ecfr.gov/api/versioner/v1/full/2026-08-25/title-40.xml","current_through":"2026-08-25","vintage":"","retrieved_at":"2026-08-27T02:26:04Z","sha256":"2bbfb9bdb66c91bdd84f22b53723e484639a818a8149bb39d77a8c3921c26d7b","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-421.23","next":"us/40-cfr-421.25"},"notice":"GroundRules: Original legal text. Not legal advice."}