ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

ENBRIDGE'S EDMONTON CONTROL CENTER RECEIVED A CALL ON NOVEMBER 20, 2012 AT APPROXIMATELY 12:48 LOCAL TIME, FROM BP CHICAP PERSONNEL AT THE MOKENA DELIVERY SITE, INDICATING THEY WERE INVESTIGATING OIL ON THE GROUND WITHIN THE FACILITY. BP MADE THE INITIAL CALL TO THE NRC AS DOCUMENTED IN PART A #4 ON THE PHMSA F 7000-1. ENBRIDGE'S LINE 6A AND LINE 14 EACH HAVE A DELIVERY LINE INTO THIS FACILITY. AT THE TIME OF BP'S CALL INTO ENBRIDGE'S ECC, LINE 6A WAS NOT DELIVERING INTO MOKENA, AND LINE 14 WAS DELIVERING TO THE EXXON MOBIL FACILITY AT MOKENA. LINE 14 WAS SHUT DOWN UNTIL FURTHER INVESTIGATION OF THE RELEASE SOURCE COULD BE COMPLETED BY BP CHICAP AND ENBRIDGE FIELD PERSONNEL. ENBRIDGE PERSONNEL DISCOVERED THE LEAK WAS IN THE AREA OF TANK 12, NEAR THE LOCATION OF AN ENBRIDGE RELIEF LINE. ALL DELIVERY AND RELIEF LINES FROM THE ADJACENT ENBRIDGE STATION TO BP CHICAP WERE LOCKED OUT UNTIL FIELD PERSONNEL COULD POSITIVELY IDENTIFY THE SOURCE OF THE OIL. ON NOVEMBER 21 AT APPROXIMATELY 18:00 THE LEAK WAS CONFIRMED TO BE ON THE ENBRIDGE RELIEF LINE NEAR TANK 12. THE RELIEF LINE PIPING WAS MANUFACTURED BY USS AND IS COMPRISED OF 20"" DIAMETER PIPE BY 0.250"" NOMINAL WALL THICKNESS, API 5L GRADE X42 LINE PIPE STEEL THAT WAS INSTALLED IN 1993 WITH A HIGH FREQUENCY ELECTRIC RESISTANCE WELDED SEAM AND FUSION BOND EPOXY COATING. WHEN IT WAS DISCOVERED THAT THE LEAK WAS ON THE ENBRIDGE RELIEF LINE, ENBRIDGE COMPLETED A CALL TO THE NRC AT 19:14 ON NOVEMBER 21, NRC# 1031299 AS DOCUMENTED IN PART A #7. FURTHER INVESTIGATION OF THE SOURCE OF OIL REVEALED THAT THERE WAS NO CHECK VALVE AND THE RELIEF LINE WAS EXPOSED TO HEAD PRESSURE FROM TANK 13. IN ORDER TO PROVIDE ALTERNATE SAFE DELIVERY OPERATIONS TO EXXON MOBIL AT THE MOKENA FACILITY WHILE THE PRESSURE RELIEF SYSTEM IS OUT OF SERVICE FOR REPAIR, A TEMPORARY PROCEDURE WAS DEVELOPED UNTIL THE RELIEF LINES ARE BACK IN OPERATION. THE INITIAL PIECE OF FAILED PIPING WAS CUT OUT AND HAS BEEN REPLACED. IT WAS SUSPECTED AT THE TIME THE CAUSE OF THE FAILURE WAS INTERNAL CORROSION, DUE TO THE FAILURE OCCURRING IN A LOW SPOT. AT THE SAME TIME THIS REPAIR WAS DONE, ENBRIDGE STARTED AN ELEVATION STUDY TO IDENTIFY OTHER LOW SPOTS ON THE RELIEF LINE AND TO DETERMINE IF INTERNAL CORROSION MAY EXIST IN OTHER LOCATIONS. A DEFECT WAS DISCOVERED DURING SANDBLASTING IN PREPARATION FOR NDE. THAT SEGMENT WAS CUT OUT AND REPLACED. NDE CONFIRMED PIPE INTEGRITY AT ALL OTHER TESTED LOCATIONS WITH THE EXCEPTION OF THE LINE NEAR TANK 13, WHICH WAS NOT COMPLETELY EXCAVATED. A FLANGE AND BLIND WAS INSTALLED TO ISOLATE THE RELIEF LINE UPSTREAM OF THE AFOREMENTIONED PIPING TO TANK 13. A HYDROTEST WAS SUCCESSFULLY COMPLETED ON THE SEGMENT OF THE RELIEF LINE TO TANK 11, AND THAT SEGMENT HAS BEEN PLACED BACK INTO SERVICE. REPAIRS CONTINUE AND IT IS ANTICIPATED THEY WILL BE COMPLETE BY THE END OF FIRST QUARTER 2013. CLEANUP AND RESTORATION OF THE SITE IS IN PROGRESS AND IT IS ANTICIPATED TO BE COMPLETED BY THE END OF JANUARY 2013. UPDATE - 5/7/13 METALLURGICAL ANALYSIS CONFIRMED INTERNAL CORROSION AS THE CAUSE. REPAIRS, CLEAN UP AND RESTORATION HAVE BEEN COMPLETED WITH THE EXCEPTION OF A SEPARATE SECTION OF THIS LINE THAT TIES INTO A DIFFERENT TANK AS A BACK-UP IN CASE BP TAKES THEIR TANK OUT OF SERVICE. AN OUTAGE IS SCHEDULED FOR JULY 24, 2013 TO COMPLETE THIS WORK. APPROXIMATELY 20,200 YARDS OF CONTAMINATED SOIL HAS BEEN REMOVED FROM THE RELEASE SITE. UPDATE - 9/27/13 SCHEDULED OUTAGE WAS PUSHED BACK WITH A NEW COMPLETION DATE OF OCTOBER 9, 2013. UPDATE - 4/22/14 THE FINAL REPAIR WORK WAS SUCCESSFULLY COMPLETED ON MARCH 24, 2014.