ENBRIDGE PIPELINES (NORTH DAKOTA) LLC

Incident Narrative

"ON THE MORNING OF FEBRUARY 25, 2011, THE MINOT AREA MAINTENANCE TECHNICIAN NOTICED THAT THE SUMP IN THE INCOMING MANIFOLD AREA HAD OVERFLOWED AND THERE WAS CRUDE OIL ON THE GROUND. SUMP MAINTENANCE WAS BEING PERFORMED ON FEBRUARY 24, 2011 DUE TO PARAFFIN BUILD UP ON THE SUMP BOTTOM, CAUSING THE MECHANICAL SUMP PUMP SWITCH TO FAIL. THE MINOT AREA UTILITY/GAUGER WAS CIRCULATING THE SUMP WITH CHEMICAL TO DISSOLVE THE PARAFFIN BUILD UP. THE DISCHARGE VALVE FROM THE SUMP PUMP WAS CLOSED AND THE BYPASS WAS OPEN WHILE CIRCULATING THE SUMP. THE MINOT AREA UTILITY/GAUGER WAS CALLED TO BERTHOLD FOR AN EMERGENCY LINE LOCATE. THE MINOT AREA UTILITY/GAUGER LEFT THE SUMP CIRCULATING AND WHEN HE RETURNED TO MINOT AT 5:30 P.M. HE FORGOT HE HAD LEFT THE SUMP PUMP RUNNING. CONTROL CENTER CONTACTED THE MINOT AREA SUPERVISOR AT APPROXIMATELY 8:10 P.M., NOTICING THAT THE SUMP PUMP WAS STILL RUNNING FROM THE MAINTENANCE ACTIVITIES IN THE AFTERNOON. THE MINOT AREA SUPERVISOR ARRIVED ON SITE AT APPROXIMATELY THE SAME TIME AS HE WAS ALREADY IN ROUTE TO THE FACILITY DUE TO MEETING SMART PIG TRACKING CREW ON SITE. HE CONFIRMED THAT THE SUMP PUMP WAS STILL RUNNING. HE OPENED THE DISCHARGE VALVE AND CLOSED THE BYPASS VALVE TO PUMP THE SUMP OUT. WHEN THE TANK LEVEL WAS DOWN, HE TURNED THE SUMP PUMP OFF, LEFT THE HOA SWITCH IN THE OFF POSITION AND THE DISCHARGE VALVE IN THE OPEN POSITION. HE THEN LEFT THE FACILITY FOR THE EVENING. INTERVIEWS DETERMINED THAT THE AREA SUPERVISOR THOUGHT THAT THE BOTTOM SWITCH WOULD NOT ACTIVATE AND THOUGHT IT WAS BETTER TO DEACTIVATE THE SUMP (THERE ARE NO PUMP SEAL DRAINS CONNECTED TO THIS SUMP) RATHER THAN HAVE THE SUMP NOT SHUTOFF ON LOW LEVEL. THE EMPLOYEE CALLED THE CONTROL CENTER TO SEE IF ALARMS HAD CLEARED BUT DID NOT NOTIFY THE CONTROL CENTER THAT THE SUMP PUMP HOA SWITCH WAS IN AN OFF POSITION AND UNABLE TO START. IT WAS LATER DETERMINED PRODUCT HAD BACK-FLOWED INTO THE SUMP THROUGH THE DISCHARGE CHECK VALVE ON THE SUMP PUMP, LEADING TO SUMP OVERFLOW."