ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

ON MARCH 2, 2021 AT APPROXIMATELY 3:13 PM, OPERATIONS PERSONNEL AT THE VIKING STATION WITNESSED OIL SPRAYING OUT OF THE LINE 4 FACILITY PIPING NEAR THE CASE PRESSURE TRANSMITTERS, JUST UPSTREAM OF THE PRESSURE CONTROL VALVE. THE EDMONTON CONTROL CENTER WAS IMMEDIATELY NOTIFIED OF THE RELEASE AND VIKING STATION WAS ISOLATED. IT IS ESTIMATED THAT APPROXIMATELY 4 BARRELS OF CRUDE WAS RELEASED. THE SOURCE OF THE PRODUCT WAS DETERMINED TO BE THE PRESSURE TRANSMITTER FLEX HOSE. THE FAILED FLEX HOSE WAS REPLACED AND APPROXIMATELY 75 CUBIC YARDS OF CONTAMINATED SOIL WAS REMOVED FROM THE RELEASE SITE. THE FAILED FLEX HOSE WAS SENT OUT FOR A THIRD-PARTY ANALYSIS WHICH DETERMINED THE CAUSE TO BE DUE TO A CIRCUMFERENTIAL CRACK THAT WAS OBSERVED IN THE STAINLESS STEEL CORE OF THE FLEX HOSE, 1.5 INCHES AWAY FROM THE END CONNECTION WHERE THE OUTSIDE BRAID AND INSIDE CORE WERE WELDED TOGETHER. A DEFORMATION WAS DISCOVERED AT THE END CONNECTION NEAREST TO THE FAILURE, INDICATING A LARGE EXTENT OF BENDING LIKELY DUE TO INCORRECT INSTALLATION PRACTICES. AS A RESULT OF THE FINDINGS FROM THE INVESTIGATION, PARTICULARLY AS IT RELATES TO THE CONFIGURATION OF THE FLEX HOSE AND THE ROLE IT PLAYED IN THE FAILURE, A QUALITY BULLETIN WILL BE ISSUED COMPANY WIDE. FOR EXISTING FLEX HOSES, THE QUALITY BULLETIN WILL PROVIDE DIRECTION REGARDING THE INSPECTION OF THE HOSES TO CONFIRM WHETHER THEY ADHERE TO THE APPLICABLE INSTALLATION GUIDE AS RECOMMENDED BY THE MANUFACTURER.