ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

ON MARCH 22, 2012 AT APPROXIMATELY 10:45, A SMALL AMOUNT OF OIL WAS OBSERVED NEAR THE LINE 2 VALVE #CR-2-SDV-1 AT THE CLEARBROOK TERMINAL. THE CONTROL CENTER WAS NOTIFIED AND LINES 1, 2 AND 3 WERE IMMEDIATELY SHUT DOWN. THE BEMIDJI PLM RESPONDED TO INVESTIGATE THE SOURCE OF THE OIL. AFTER EXCAVATING THE LINE 2 DISCHARGE VALVE AREA, IT WAS DISCOVERED THAT ONE OF THE TWO O RINGS OF THE SEAL, ALONG WITH THE BONNET, HAD FAILED ON THE VALVE AND SEEPED THROUGH A MODIFIED TELL TALE PLUG. A NEW PLUG WAS INSTALLED. THE REPLACEMENT PARTS ARE ON ORDER AND EXPECTED TO ARRIVE IN THE NEXT WEEK. CURRENTLY OIL IS SLOWLY LEAKING FROM THE LOWER SEAL. THERE IS NO OIL IN THE YOKE TUBE, WHICH CONFIRMS THE SECONDARY/LOWER O RING IS HOLDING AND THE RISK OF OIL BEING RELEASED PAST THE STEM IS MINIMAL WITHIN MINUTES OF STARTING EXCAVATION NEAR THE LINE 2 VALVE #CR-2-SDV-1, OIL WAS ALSO OBSERVED IN THE VICINITY OF THE THE LINE 3 SENDING TRAP. THE TWO AREAS ARE APPROXIMATELY 50 FEET AWAY FROM EACH OTHER. THE LINES IN THE IMMEDIATE AREA (LINES 1,2 AND 3) HAD BEEN SHUT DOWN FOR THE LINE 2 DISCHARGE VALVE INCIDENT. EXCAVATION OF THE LINE 3 SENDING TRAP AREA DISCOVERED THAT FROST HEAVE HAD PUSHED ON THE VALVE SEAL PACKING LINE, CAUSING IT TO CRACK, WHICH ALLOWED OIL TO SEEP UP THROUGH THE FAILED PIPING. THE FAILED PIPING AND THE ADDITIONAL TWO SMALL DIAMETER PIPING RUNS WILL BE REPLACED. IN ADDITION, A BRACKET WILL BE INSTALLED TO FURTHER RESTRICT THE MOVEMENT OF THE PIPES ON THIS VALVE. THE PRIMARY AND SECONDARY SEALS ON THE LINE 2 VALVE #CR-2-SDV-1 WERE REPLACED SEPTEMBER 20, 2012. THE TOTAL AMOUNT OF CONTAMINATED SOIL REMOVED FROM BOTH LEAK SITES WAS APPROXIMATELY 120 CUBIC YARDS.