ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

ON NOVEMBER 2, 2022, AT APPROXIMATELY 12:25 PM CDT, ENBRIDGE TECHNICIAN FOUND PRODUCT WEEPING FROM THE VALVE BONNET OF VALVE 0995.90-4-V-1 AT THE DEER RIVER STATION. AN ESTIMATED 2 GALLONS OF CRUDE OIL WAS RELEASED ONTO THE GRAVEL BELOW THE VALVE. THE EDMONTON CONTROL CENTER WAS NOTIFIED, AND LINE 4 WAS SHUT DOWN. PRODUCT ON THE VALVE BODY WAS CLEANED UP AND IMPACTED SOIL REMOVED AND PROPERLY DISPOSED OF. CONTAINMENT WAS PLACED UNDER THE VALVE AND THE AREA WAS MONITORED WHILE PLANS WERE DEVELOPED FOR THE REPAIR. IT WAS DETERMINED AT 4:00 PM CDT THAT THE COST OF THE REPAIR WOULD EXCEED $50,000 DUE TO DRAIN UP VOLUMES. THE NRC WAS NOTIFIED AT 4:32 PM CDT (NRC #1351572). THE BONNET O-RING WAS REPLACED, AND THE LINE WAS RETURNED TO SERVICE. THE 48-HOUR NRC UPDATE WAS MADE ON NOVEMBER 4, 2022 AT 1:55 PM CDT (NRC #1351733). APPROXIMATELY 10 YARDS OF CONTAMINATED SOIL WAS REMOVED FROM THE RELEASE SITE. THE FAILED O-RING WAS ANALYZED BY A THIRD-PARTY VENDOR AS PART OF THE INVESTIGATION, AND IT WAS DETERMINED THAT THE CAUSE WAS DUE TO IMPROPER INSTALLATION. ONCE THE BONNET HAD BEEN SEPARATED FROM THE VALVE BODY, IT WAS OBSERVED THAT THE O-RING SEAL WAS SEVERED AND PROTRUDING INTO THE VALVE BODY INDICATING THAT THE O-RING SLIPPED OUT DURING THE INSTALLATION. THE VALVE MANUFACTURER HAS CHANGED THE DESIGN OF THIS O-RING SEAL AND SEAT CONFIGURATION TO PROVIDE A CHANNEL FOR THE O-RING TO REST IN. AN O-RING RETAINER PLATE IS RECOMMENDED BY THE MANUFACTURER FOR FUTURE O-RING REPLACEMENTS. ENBRIDGE WILL INCLUDE THIS O-RING RETAINER FOR FUTURE O-RING REPLACEMENTS ON VALVES OF THIS VINTAGE. THE ACTUAL VOLUME RELEASED AT DEER RIVER STATION WAS 0.05 BARRELS OF CRUDE OIL. THE PHMSA PORTAL DOES NOT RECOGNIZE VOLUMES LESS THAN 0.1 BARRELS THEREFORE THAT IS THE VOLUME ENTERED.