{"data":{"id":"us/40-cfr-471.23","jurisdiction":"us","citation":"40 CFR 471.23","heading":"New source performance standards (NSPS).","body":"Any new source subject to this subpart must achieve the following new source performance standards. The mass of pollutants in the magnesium forming process wastewater shall not exceed the following values:\n(a) Rolling spent emulsions.\nSubpart B—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off/kg (pounds per million off-pounds) of magnesium rolled with emulsions\nChromium 0.028 0.011\nZinc 0.076 0.032\nAmmonia 9.95 4.37\nFluoride 4.44 1.97\nOil and grease 0.746 0.746\nTSS 1.12 0.895\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(b) Forging spent lubricants—subpart B—NSPS. There shall be no discharge of process wastewater pollutants.\n(c) Forging contact cooling water.\nSubpart B—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off/kg (pounds per million off-pounds) of forged magnesium cooled with water\nChromium 0.107 0.044\nZinc 0.295 0.122\nAmmonia 38.5 17.0\nFluoride 17.2 7.63\nOil and grease 2.89 2.89\nTSS 4.34 3.47\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(d) Forging equipment cleaning wastewater.\nSubpart B—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off/kg (pounds per million off-pounds) of magnesium forged\nChromium 0.002 0.0006\nZinc 0.004 0.002\nAmmonia 0.532 0.234\nFluoride 0.238 0.106\nOil and grease 0.040 0.040\nTSS 0.060 0.048\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(e) Direct chill casting contact cooling water.\nSubpart B—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of magnesium cast with direct chill methods\nChromium 1.46 0.593\nZinc 4.03 1.66\nAmmonia 527 232\nFluoride 235 105\nOil and grease 39.5 39.5\nTSS 59.3 47.4\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(f) Surface treatment spent baths.\nSubpart B—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of magnesium surface treated\nChromium 0.173 0.070\nZinc 0.476 0.196\nAmmonia 62.1 27.3\nFluoride 27.8 12.3\nOil and grease 4.66 4.66\nTSS 6.99 5.60\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times\n(g) Surface treatment rinse.\nSubpart B—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pound pers million off-pounds) of magnesium surface treated\nChromium 0.700 0.284\nZinc 1.93 0.794\nAmmonia 252 111\nFluoride 113 49\nOil and grease 18.9 18.9\nTSS 28.4 22.7\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times\n(h) Sawing or grinding spent emulsions.\nSubpart B—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of magnesium sawed or ground\nChromium 0.007 0.003\nZinc 0.020 0.008\nAmmonia 2.60 1.15\nFluoride 1.16 0.515\nOil and grease 0.195 0.195\nTSS 0.293 0.234\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.\n(i) Degreasing spent Solvents—subpart B—NSPS. There shall be no discharge of process wastewater pollutants.\n(j) Wet air pollution control scrubber blowdown.\nSubpart B—NSPS\nPollutant or pollutant property Maximum for any 1 day Maximum for monthly average\nmg/off-kg (pounds per million off-pounds) of magnesium sanded and repaired or forged\nChromium 0.229 0.093\nZinc 0.632 0.260\nAmmonia 82.5 36.3\nFluoride 36.9 16.4\nOil and grease 6.19 6.19\nTSS 9.29 7.43\npH (1) (1)\n1 Within the range of 7.5 to 10.0 at all times.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS","PART 471—NONFERROUS METALS FORMING AND METAL POWDERS POINT SOURCE CATEGORY","Subpart B—Magnesium Forming 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":"d8a86f671e58dcd5d86ee69485c938a563fb648d5a110df94c4e8f82b1e7ec1e","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-471.22","next":"us/40-cfr-471.24"},"notice":"GroundRules: Original legal text. Not legal advice."}