Document 6bNbQJz0EzZkqJyNeGdLbV4yR

July 30, 2025 TRANSMITTED VIA EMAIL Blair Spencer HSE Manager Cantium, LLC 111 Park Place Drive, Suite 100 Covington, LA 70433 blair.spencer@cantium.us Re: Notice of Potential Violation and Opportunity to Confer NPDES Permit: GMG290615 Dear Mr. Spencer: Information currently available to the United States Environmental Protection Agency, Region 6 (EPA) suggests that Cantium, LLC (Cantium) may have 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 EPA, via a conference call or in writing, of any information which EPA should consider with respect to the potential violations. Cantium owns or operates facilities that discharge pollutants to the waters of the contiguous zone or the ocean under the permit, GMG290615. EPA identified the potential violations in a file review for the monitoring period of May 11, 2023 to May 31, 2025 and in a compliance evaluation inspection conducted by the United States Bureau of Safety and Environmental Enforcement (BSEE) on June 24, 2024. The potential violations are listed in Attachments contained herein. Within 15 calendar days of receipt of this letter, please indicate if you would like to discuss this matter by contacting Uma Lad of my staff at (214) 665-8563 or Lad.Uma@epa.gov. Sincerely, Bryant Smalley Chief Water Enforcement Branch Notice of Potential Violation and Opportunity to Confer NPDES Permit: GMG290615 Page 2 Enclosures Attachment A - DMR Non-Receipt Violations Attachment B - BSEE Inspection Violations 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) DMR Non-Receipt Violations GMG290615 Monitoring Period End Date 07/31/2023 Monitoring Period From 07/01/2023 to 09/30/2023 Limit Set 0009-PR Lease Area/Block1 Parameter BM-3 00010 - Temperature, water degree centigrade NODI Code2 **E** DMR Due Date 11/30/2023 DMR Submission Date 11/30/2023 1 BM = Bay Marchand 2 Information on DMR Non-Receipt status can be found on here: NPDES DMR Non-Receipt Status Search Help. ATTACHMENT B BSEE Inspection Report Violations GMG290615 Permitted Features 0058, 0063, 0064 Inspection Date: 06/24/2024 BSEE Inspection ID: 492490736 Records Review Period: 05/01/2022 - 04/30/2024 Lease Area/Block: Main Pass 42 Limit Set CT DC PW PR PR PR PR PR PR SW Description of Violations The operator is incorrectly submitting miscellaneous discharges under miscellaneous discharges (chemically treated) in DMR. There was no Best Management Practice (BMP) Plan onsite. Multiple chains of custody (COC) for produced water samples were incomplete. The lab received monthly produced water samples that were not properly sealed. Temperature analyses for produced water were not reported on DMR. The operator is not reporting the highest estimated monthly flow rate for produced water discharges. Custody seals for produced water samples are reused. Sample custody seals were not signed at time of produced water sampling as witnessed during the inspection. The COC was not filled out at the time BSEE and EPA were onsite to witness personnel collect a produced water oil and grease sample. The Marine Sanitation Device (MSD) bypass line cannot be easily chlorinated. The site map for the NOI is incorrect. There was no thermometer in the sample storage area. Violation Date(s) 06/24/2024 06/24/2024 05/01/2022 - 04/30/2024 05/01/2022 - 04/30/2024 05/01/2022 - 04/30/2024 05/01/2022 - 04/30/2024 06/24/2024 06/24/2024 06/24/2024 06/24/2024 06/24/2024 06/24/2024 Permit Citation Part II, Sec. D, 4 Part II, Section B, 2, c, 2, Best Management Practices, b Part II, Sec. C, 4, a-g Part I, Sec. B, Note 1-2 Part II, Sec. D, 4 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 B, 3, a Part I, Sec A, 2 (facility map) Part I, Sec. B, Note 1-2