ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

ON FEBRUARY 2 AT 10:55 AM, WHILE COMPLETING ROUTINE ROUNDS AT THE DEER RIVER STATION, THE TECHNICIAN DISCOVERED APPROXIMATELY 1/2 GALLON OF CRUDE OIL TO BE LEAKING FROM THE LINE 4 DISCHARGE PRESSURE TRANSMITTER (4-PT-1D/4-PT-2D) WHERE THE BRANCH CONNECTION FITTING IS WELDED TO THE STATION PIPING. LINE 4 WAS DOWN FOR A DELIVERY AT THE TIME OF THE DISCOVERY. PIPELINE MAINTENANCE WAS DISPATCHED TO THE STATION TO CLEAN UP THE OIL AND BEGIN NECESSARY REPAIRS. INVESTIGATION REVEALED CRACKING IN THE 2"" BRANCH CONNECTION WELD OF THE PRESSURE TRANSMITTER FITTING. THE PRESSURE TRANSMITTER BRANCH CONNECTION (4-PT-1D/4-PT-2D) WAS RELOCATED ON THE STATION PIPING. AN ENCAPSULATION FITTING DESIGNED AND TESTED TO THE SYSTEM PRESSURE RATING WAS INSTALLED OVER THE AFFECTED /CRACKED FITTING AND FILLED WITH NON-CORROSIVE FLUID. AT THIS TIME, THE CAUSE OF THE FAILURE HAS BEEN ATTRIBUTED TO FATIGUE CRACKING OF THE BRANCH CONNECTION WELD DUE TO VIBRATION FROM THE NEARBY PRESSURE CONTROL VALVE. THE CURRENT PATH FORWARD WITH THE FAILED CONNECTION INCLUDES THE REMOVAL OF THE FAILED SECTION OF STATION PIPING AND A METALLURGICAL ANALYSIS OF THE FAILED WELDED BRANCH CONNECTION. THE CUT OUT IS EXPECTED TO BE COMPLETED BY END OF FIRST QUARTER 2016. LESS THAN 1 CUBIC YARD OF CONTAMINATED SOIL HAS BEEN REMOVED FROM THE RELEASE SITE.