Document ZnV1R9QRwqqKKjv9ODOD6ZyyO

July 8, 2025 TRANSMITTED VIA EMAIL John Poole, VP HSE&R W & T Energy VI, LLC 5718 Westheimer Rd, Suite 700 Houston, Texas 77057 jpoole@wtoffshore.com Re: Notice of Potential Violation and Opportunity to Confer NPDES Permit: GMG290382 Dear Mr. Poole: The United States Environmental Protection Agency, Region 6 (EPA) finds that W & T Energy VI, LLC (W&T) has potentially committed violations of Section 301 of the Clean Water Act (CWA), 33 U.S.C. 1311 and National Pollution Discharge Elimination System (NPDES) General Permit for Offshore Activities (GMG290000) at the Permitted Features listed in the Enclosures. By this letter, EPA is extending to you an opportunity to advise the Agency, via a conference call or in writing, of any information which EPA should consider with respect to the potential violations. W&T owns or operates facilities that discharge pollutants to a water of the United States under the permit, GMG290382. EPA identified the potential violations in a file review for the monitoring period of May 11, 2023 to May 31, 2025 and in compliance evaluation inspections conducted by the United States Bureau of Safety and Environmental Enforcement (BSEE) on August 9, 2024 and May 20, 2025. Within 15 days of receipt of this letter, please indicate if you would like to discuss this matter by contacting Kerri McCabe of my staff at (214) 665-6467 or mccabe.kerri@epa.gov. Sincerely, JEANNE ECKHART Digitally signed by JEANNE ECKHART Date: 2025.07.09 10:43:13 -05'00' Bryant Smalley Chief Water Enforcement Branch Notice of Potential Violation and Opportunity to Confer NPDES Permit: GMG290382 Page 2 Enclosures Attachment A - Effluent Violations Attachment B - DMR Non-Receipt Violations Attachment C - BSEE Inspection Violations - PF0005 Attachment D - BSEE Inspection Violations - PF0008 ec: Judy Triche, Chief, Environmental Monitoring Unit, BSEE judy.triche@bsee.gov Review Period: 05/11/2023 - 05/31/2025 Attachment A Environmental Protection Agency Integrated Compliance Information System (ICIS) Effluent Violations GMG290382 Monitoring Period End Date 03/31/2025 11/30/2024 Monitoring Period From 01/01/2025 to 03/31/2025 From 10/01/2024 to 12/31/2024 Limit Set 0005-DD 0005-DD Lease Area/Block1 Parameter MC-243 82597 - Deck drainage, free oil MC-243 82597 - Deck drainage, free oil Mon. Loc. 1 1 Value Type/ Stat. Base C3 MO TOTAL C3 MO TOTAL Reported Limit Value/Units Value/Units 1 day <= 0 days 1 day <= 0 days 1 MC = Mississippi Canyon Review Period: 05/11/2023 - 05/31/2025 Attachment B Environmental Protection Agency Integrated Compliance Information System (ICIS) DMR Non-Receipt Violations GMG290382 Monitoring Period End Date 04/30/2024 04/30/2024 04/30/2024 11/30/2023 Monitoring Period From 04/01/2024 to 06/30/2024 From 04/01/2024 to 06/30/2024 From 04/01/2024 to 06/30/2024 From 10/01/2023 to 12/31/2023 Limit Set 0008-PR Lease Area/Block2 Parameter VK-823 00010 - Temperature, water degree centigrade NODI Code **E** DMR Due Date 08/31/2024 DMR Submission Date 08/27/2024 0008-PR VK-823 82599 - Produced water, oil and grease **E** 08/31/2024 08/27/2024 0008-PR VK-823 82599 - Produced water, oil and grease **E** 08/31/2024 08/27/2024 0008-SW VK-823 82605 - Sanitary waste, residual chlorine **E** 02/29/2024 02/29/2024 2 VK = Viosca Knoll Inspection Date: 08/09/2024 BSEE Inspection ID: 508808543 Records Review Period: 7/1/2022-6/30/2024 Lease Area/Block: Mississippi Canyon 243 ATTACHMENT C BSEE Inspection Report Violations GMG290382 Permitted Feature 0005 PF/Limit Set Description of Violations 0005-DD 0005 - PW 0005 - PW 0005 - PW 0005 - PW 0005 - PW Multiple potential bypass lines leading to deck drains. Multiple incomplete chains of custody (COC) for produced water samples. June 2024 oil & grease sample results for produced water were not reported on the Discharge Monitoring Report (DMR). Produced water from the temporary CETCO system was not sampled in July and August 2024. Oil & grease sample for produced water was transferred from one container to another during collection. No thermometer in sample storage area. 0005 - PW Produced water samples not collected after final treatment. 0005-PW Flotation unit for produced water treatment was offline. Violation Date(s) 08/09/2024 7/1/20226/30/2024 06/2024 07/2024 08/2024 08/09/2024 08/09/2024 08/09/2024 08/09/2024 Permit Citation Part II, Sec. B, 3, a Part II, Sec. C, 4, a-g Part I, Sec. B, 4, b; Part II, Sec. D, 4 Part I, Sec. B, Note 1-2 Part I, Sec. B, Note 1-2 Part I, Sec. B, Note 1-2 Part II, Sec. C, 4, a-g Part II, Sec. B, 3, a Inspection Date: 05/20/2025 BSEE Inspection ID: 553203928 Records Review Period: 7/1/2023-2/28/2025 Lease Area/Block: Viosca Knoll 823 ATTACHMENT D BSEE Inspection Report Violations GMG290382 Permitted Feature 0008 PF/Limit Set 0008 - PW 0008 - PW 0008 - PW 0008 - PW 0008 - PW Description of Violations Multiple incomplete chains of custody (COC) for produced water samples. Oil and grease samples for produced water not properly preserved when received by the lab with a pH above 2 standard units. DMR reports are not consistent with information regarding produced water discharges. Multiple DMR produced water oil and grease monthly averages are incorrect. Facility personnel are unfamiliar with sheen sampling protocols. Violation Date 05/20/2025 05/20/2025 05/20/2025 05/20/2025 05/20/2025 0008 - PW 0008 - PW 0008 - PW 0008 - PW Facility did not have any sheen sampling bottles onsite. COC not received by lab for the November 2024 oil and grease sample for produced water. It was sent later by the operator. Facility personnel analyze the temperature of the produced water samples by placing the thermometer directly in the sample sent to the lab. Facility does not use custody seals on the produced water oil and grease samples. 05/20/2025 November 2024 05/20/2025 05/20/2025 Permit Citation Part II, Sec. C, 4, a-g Part I, Sec. B, Note 1-2 Part II, Section D, 4 Part II, Section D, 4 Part I, Section B, 4, b Part I, Section B, 4, b Part I, Sec. B, Note 1-2 Part I, Sec. B, Note 1-2 Part I, Sec. B, Note 1-2