ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

ON MAY 18, 2023, AT APPROXIMATELY 8:15 AM CDT, AN ENBRIDGE TECHNICIAN PERFORMING MAINTENANCE ACTIVITIES AT THE VIKING STATION FOUND CRUDE OIL ON THE GROUND AT THE BASE OF THE LINE 2 PUMPHOUSE COOLING FAN PIPE. THE EDMONTON CONTROL CENTER WAS NOTIFIED, AND LINE 2 WAS SHUT DOWN. OPERATIONS PERSONNEL IMMEDIATELY BEGAN TO INVESTIGATE THE SOURCE OF THE RELEASE. LINE 2 WAS RESTARTED AT REDUCED RATES WITH VIKING STATION ISOLATED. ADDITIONAL EQUIPMENT AND RESOURCES WERE CALLED IN TO ASSIST IN EXCAVATION AND CLEANUP OF THE AREA. IT WAS DETERMINED AT 12:10 PM CDT THAT THE COST WOULD EXCEED THE NRC REPORTING THRESHOLD DUE TO THE EXTENT OF EXCAVATION NEEDED TO FIND THE SOURCE OF THE RELEASE. THE NRC WAS NOTIFIED ON MAY 18, 2023, AT 12:26 PM CDT (NRC# 1367607). THE MINNESOTA DUTY OFFICER WAS ALSO CONTACTED (#213599). EXCAVATION AND CLEAN UP PROCEEDED UNTIL THE SOURCE OF THE RELEASE WAS IDENTIFY AS A FAILED O-RING ON A BURIED CHECK VALVE. THE 48-HOUR NRC UPDATE WAS MADE ON MAY 20, 2023, AT 9:55 AM CDT (NRC #1367759). THE O-RING WAS REPLACED, AND VIKING STATION WAS DEISOLATED. APPROXIMATELY 5 GALLONS OF CRUDE OIL WAS RELEASED. THE INVESTIGATION DETERMINED THE CAUSE OF THE RELEASE WAS DUE TO NORMAL WEAR AND TEAR OF THE O-RING FROM YEARS OF SERVICE. APPROXIMATELY 100 CUBIC YARDS OF CONTAMINATED SOIL WAS REMOVED FROM THE RELEASE SITE AND PROPERLY DISPOSED OF.