"COLUMBIA GAS TRANSMISSION, LLC"

Incident Narrative

"ON MARCH 25TH, 2025, AT APPROXIMATELY 09:51 EASTERN DAYLIGHT TIME (EDT), THE PRESENCE OF NATURAL GAS WAS IDENTIFIED BY TC ENERGY PROJECT PERSONNEL WHILE PERFORMING A CASING MITIGATION PROJECT, A SUBSEQUENT LEAKAGE SURVEY WAS CONDUCTED TO IDENTIFY THE LOCATION OF THE SOURCE OF THIS GAS RELEASE. ON MARCH 26TH AT APPROXIMATELY 10:00 EDT, AFTER FURTHER INVESTIGATION, IT WAS IDENTIFIED THE LEAK WAS FROM A VALVE STEM ON LINE D-76 NEAR THE OHIO STATE ROUTE19 HIGHWAY. AT APPROXIMATELY 13:26 EDT IT WAS CONFIRMED THE COST OF REPAIR MAY EXCEED $145,400 AND THE INCIDENT WAS PROMPTLY REPORTED TO THE NATIONAL RESPONSE CENTER (NRC). THE INITIAL PLAN FOR REPAIR WAS TO INSTALL STOPPLES, BYPASS THE VALVE, THE CASING AND GAS PIPELINE LOCATED UNDER THE HIGHWAY. ON APRIL 3RD, 2025, AT APPROXIMATELY 15:00 EDT A MECHANICAL FITTING THAT WAS LOCATED A FEW FEET DOWNSTREAM OF THE LEAKING VALVE FAILED AND CAUSED THE RELEASE OF APPROXIMATELY 7,254 MCF OF NATURAL GAS INTO THE ATMOSPHERE. THE PROJECT TEAM EVACUATED THE SITE OF THE INCIDENT AND CALLED THE EMERGENCY RESPONDERS. OHIO SR 19 HIGHWAY WAS CLOSED AT 15:25 EDT, AND 129 RESIDENCES WERE EVACUATED. A COURTESY CALL WAS MADE TO THE PUBLIC UTILITIES COMMISSION OF OHIO CHIEF ' FACILITY AND OPERATIONS FIELD DIVISION AT 15:27 EDT AND PHMSA ACCIDENT INCIDENT DIVISION AT 15:39 EDT. THERE WAS NO FIRE, EXPLOSION, INJURY, OR FATALITY. AT 18:49 PM EDT THE AFFECTED SECTION OF THE PIPELINE WAS ISOLATED AND BLOWN DOWN. THERE WAS A LOSS OF GAS SERVICE TO TWO COLUMBIA GAS OF OHIO POINTS OF DELIVERY. THE REPAIR WAS COMPLETED BY REMOVING THE FAILED MECHANICAL FITTING AND LEAKING VALVE. LINE D-76 WAS RETURNED INTO SERVICE ON APRIL 6, 2025, AT 16:45 EDT. THE FAILED MECHANICAL FITTING AND LEAKING VALVE WERE PROTECTED AND PRESERVED AS EVIDENCE AND SENT TO A LOCAL TC ENERGY OFFICE FOR FURTHER INVESTIGATION."