StacksVerified U.S. regulatory reference

40 CFR §421.252

Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Except as provided in 40 CFR 125.30 through 125.32, any existing point source subject to this subpart shall achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best practicable technology currently available:
  1. (a)Smelter wet air pollution control.
  2. (b)Silver chloride reduction spent solution.
  3. (c)Electrolytic cells wet air pollution control.
  4. (d)Electrolyte preparation wet air pollution control.
  5. (e)Calciner wet air pollution control.
  6. (f)Calcine quench water.
  7. (g)Calciner stack gas contact cooling water.
  8. (h)Condenser blowdown.
  9. (i)Mercury cleaning bath water.