ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

ON MAY 3, AT APPROXIMATELY 2:00 PM AT THE PLUMMER STATION, THE LOCAL MECHANICAL TECHNICIAN NOTICED A LARGE AMOUNT OF WATER/OIL MIX IN AND AROUND THE WHISTLE AREA OF THE LINE 1 PRESSURE TRANSMITTER. THE TECHNICIAN CONTACTED THE EDMONTON CONTROL CENTER (ECC), AND HAD THE LINE IMMEDIATELY SHUT DOWN. PIPELINE MAINTENANCE CREWS WERE NOTIFIED AND ONSITE AT APPROXIMATELY 3:00 PM. A VAC TRUCK WAS USED TO REMOVE THE WATER AND OIL FROM THE WHISTLE AND FOUND THE STEM PACKING NUT ON A 2 INCH VALVE ON THE PRESSURE TRANSMITTER WAS THE SOURCE OF THE LEAK. BECAUSE NGL PRODUCT WAS IN THE PIPELINE AT THE TIME, REGION MANAGEMENT REQUESTED THE ECC TO DISPLACE THE NGL BY CRUDE OIL PRIOR TO COMPLETING THE REPAIR. WHEN THE VALVE WAS UNDER WATER WITHIN THE VERTICAL CULVERT, CREWS OBSERVED 10-20 SMALL ""BUBBLES"" PER MINUTE COMING FROM THE FITTING. DUE TO THE NATURE OF THE LEAK, IT WAS NOT ANTICIPATED THAT THE LEAKAGE RATE WOULD VARY SIGNIFICANTLY WITH TIME OR MODERATE VARIATIONS IN PIPELINE PRESSURE. WHILE MONITORING THE LOCATION AROUND THE CLOCK, CREWS WERE INSTRUCTED TO CONTACT THE ECC IMMEDIATELY IF INCREASED LEAKAGE WAS OBSERVED. ONCE CRUDE OIL CROSSED THE STATION, ON MAY 7, THE TEMPORARY HOSE WAS INSTALLED. THE PERMANENT PIPING IS CURRENTLY BEING CONFIGURED AND WILL BE READY FOR INSTALLATION IN THE NEXT FEW WEEKS. IT WAS DISCOVERED THAT FROST HEAVE PUSHING ON THE PIPE CONFIGURATION WAS THE CAUSE OF THE LEAK. APPROXIMATELY 60 CUBIC YARDS OF CONTAMINATED SOIL HAS BEEN REMOVED FROM THE LEAK SITE.