ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

ON MAY 17, 2024, AT APPROXIMATELY 7:52 PM CDT, AN ENBRIDGE TECHNICIAN AT THE WALWORTH STATION DISCOVERED CRUDE OIL HAD MISTED ONTO THE LINE 14 UNIT PUMP 3 AS WELL AS THE SURROUNDING EQUIPMENT AND NEARBY GRAVEL. THE TECHNICIAN CONTACTED THE EDMONTON CONTROL CENTER, AND THE UNIT WAS ISOLATED. AT APPROXIMATELY 8:03 PM CDT THE MANAGER ON CALL AND THE TECHNICAL SUPERVISOR WERE NOTIFIED. IT WAS DETERMINED AT THIS TIME THAT THE CLEANUP AND REPAIR COSTS WOULD EXCEED THE $50,000 NRC REPORTING THRESHOLD. OPERATIONS PERSONNEL WERE DISPATCHED TO THE SITE FOR CLEAN-UP AND REMEDIATION. IT IS ESTIMATED THAT APPROXIMATELY 15 GALLONS OF CRUDE OIL WAS RELEASED FROM A PINHOLE IN THE 1/2"" STAINLESS STEEL TUBING ON THE SEAL FLUSH LINE OF THE UNIT PUMP. THE UNIT WAS LOCKED OUT AND ISOLATED UNTIL REPAIRS COULD BE MADE. ALL IMPACTED GRAVEL HAS BEEN REMOVED FROM THE RELEASE SITE. THE NRC WAS NOTIFIED ON MAY 17, 2024, AT 8:56 PM CDT (NRC # 1399286). A 48-HOUR UPDATE TO THE NRC WAS MADE ON MAY 19, 2024, AT 12:03 PM CDT (NRC# 1399381). THE UNIT MOTOR WAS SENT IN FOR INTERNAL CLEANING WITH A THIRD PARTY, TUBING WAS REPLACED AND WENT BACK INTO SERVICE ON SEPTEMBER 12, 2024. THE CAUSE OF THE RELEASE WAS DUE TO ABRASIVE WEAR IN THE TUBING FROM SOLIDS IN THE PROCESS FLOW ALLOWING THE TUBING TO THIN OVER TIME. THIS CAUSED LOCALIZED THINNING AROUND THE 90-DEGREE BEND, ENDING IN A SMALL RUPTURE POINT IN THE TUBING. DUE TO THE EXCESSIVE WEAR WITHIN THE TUBING AND ABSENCE OF ORIFICES, THICKER WALL TUBING AND ORIFICES WILL BE INSTALLED.