GREAT LAKES GAS TRANSMISSION LIMITED PARTNERSHIP — Integrity Assurance Notification

ILI RESULTS EXTENSIONTC Energy, on behalf of Great Lakes Gas Transmission (GLGT) (OPID: 6660), is providing this §192.18 notification to the Pipeline and Hazardous Materials Safety Administration (PHMSA) regarding a delay in obtaining adequate information necessary to determine conditions within 180 days of conducting an integrity assessment, as required by §192.933(b). On May 20, 2025, a Baker Hughes EMAT ILI tool was run on GLGT Line 100, Station 4 to Station 5, Deer River Section. The delivery of the final report has been delayed beyond the normal schedule for this project and has exceeded the 180-day period that ended on November 16, 2025. Following a preliminary review of the inspection data by Baker Hughes, TC Energy identified three features that meet immediate action criteria. In response, TC Energy implemented a pressure reduction to 882 psig on September 3, 2025, and will maintain this reduced pressure until remediation is complete. Due to the features being located in inaccessible swamp terrain, TC Energy anticipates completing remediation by the end of April 2026. Baker Hughes has advised TC Energy that recent changes to its analysis processes have resulted in increased demand hours and resource capacity constraints, extending the timeline for final report completion beyond the originally agreed timeframe. A copy of Baker Hughes’ notification letter is attached for reference. The final report is currently expected to be delivered on December 22, 2025.#