{"data":{"id":"us/40-cfr-435.43","jurisdiction":"us","citation":"40 CFR 435.43","heading":"Effluent limitations guidelines representing the degree of effluent reduction attainable by the application of the best available technology economically achievable (BAT).","body":"Except as provided in 40 CFR 125.30-125.32, any existing point source subject to this subpart must achieve the following effluent limitations representing the degree of effluent reduction attainable by the application of the best available technology economically achievable (BAT):\nBAT Effluent Limitations\nStream Pollutant parameter BAT effluent limitations\nProduced Water:\n(A) All coastal areas except Cook Inlet No discharge.\n(B) Cook Inlet Oil \u0026 Grease The maximum for any one day shall not exceed 42 mg/l, and the 30-day average shall not exceed 29 mg/l.\nDrilling Fluids, Drill Cuttings, and Dewatering Effluent: 1\n(A) All coastal areas except Cook Inlet No discharge.\n(B) Cook Inlet:\nWater-based drilling fluids, drill cuttings, and dewatering effluent SPP Toxicity Minimum 96-hour LC50. of the SPP Toxicity Test 4 shall be 3% by volume.\nFree oil No discharge. 2\nDiesel oil No discharge.\nMercury 1 mg/kg dry weight maximum in the stock barite.\nCadmium 3 mg/kg dry weight maximum in the stock barite.\nNon-aqueous drilling fluids and dewatering effluent No discharge.\nDrill cuttings associated with non-aqueous drilling fluids No discharge. 5\nWell Treatment, Workover and Completion Fluids:\n(A) All coastal areas except Cook Inlet No discharge.\n(B) Cook Inlet Oil \u0026 Grease The maximum for any one day shall not exceed 42 mg/l, and the 30-day average shall not exceed 29 mg/l.\nProduced Sand No discharge.\nDeck Drainage Free Oil 3 No discharge.\nDomestic Waste Foam No discharge.\n1 BAT limitations for dewatering effluent are applicable prospectively, BAT limitations in this rule are not applicable to discharges of dewatering effluent from reserve pits which as of the effective date of this rule no longer receive drilling fluids and drill cuttings. Limitations on such discharges shall be determined by the NPDES permit issuing authority.\n2 As determined by the static sheen test. See § 435.41(ff).\n3 As determined by the presence of a film or sheen upon or a discoloration of the surface of the receiving water (visual sheen).\n4 As determined by the suspended particulate phase (SPP) toxicity test. See § 435.41(ee).\n5 When Cook Inlet operators cannot comply with this no discharge requirement due to technical limitations (see appendix 1 of subpart D of this part), Cook Inlet operators shall meet the same stock limitations (C16-C18 internal olefin) and discharge limitations for drill cuttings associated with non-aqueous drilling fluids for operators in Offshore waters (see § 435.13) in order to discharge drill cuttings associated with non-aqueous drilling fluids.","path":["Title 40—Protection of Environment","CHAPTER I—ENVIRONMENTAL PROTECTION AGENCY","SUBCHAPTER N—EFFLUENT GUIDELINES AND STANDARDS","PART 435—OIL AND GAS EXTRACTION POINT SOURCE CATEGORY","Subpart D—Coastal 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":"371148a1bf66efa686b99591e6fdfe059c137bdfb818d679497100e189c229eb","source_id":"us-cfr","stale":true,"prev":"us/40-cfr-435.42","next":"us/40-cfr-435.44"},"notice":"GroundRules: Original legal text. Not legal advice."}