ENBRIDGE ENERGY, LIMITED PARTNERSHIP

Incident Narrative

AN INTEGRITY DIG WAS EXCAVATED ON LINE 5 AT MP 1393 FOR A CRACK REPAIR. ONCE EXCAVATED THE CREW EXITED THE WORK AREA TO ALLOW AN NGL BATCH TO PASS THE WORK SITE. AT APPROXIMATELY 9:30 EST (LOCAL TIME), NGL WAS IN THE LINE WHEN THE CREW NOTICED A WET SPOT AT THE GIRTH WELD. THE WET SPOT WAS NOT PRESENT WITH CRUDE OIL. THE GIRTH WELD WAS WITHIN THE ASSESSMENT AREA OF THE INTEGRITY DIG, BUT WAS NOT THE ORIGINAL TARGET FEATURE. THE SPOT WAS CHECKED WITH SOAP AND VERIFIED TO BE A PINHOLE LEAK. THE CONTROL CENTER WAS NOTIFIED AND THE LINE WAS SHUT DOWN. REGIONAL COMPLIANCE PERSONNEL LOCATED IN SUPERIOR, WI (CENTRAL TIME ZONE) NOTIFIED NRC AT 11:30 CST (REPORT NUMBER 1102907). ESCANABA PIPELINE MAINTENANCE CREW WAS MOBILIZED TO THE SITE TO COMPLETE A FULL ASSESSMENT OF SITE CONDITIONS. AFTER FURTHER REVIEW IT WAS DETERMINED THAT THE BEST PATH FORWARD WAS TO MOVE THE NGL OUT OF THE SECTION PRIOR TO COMMENCING WORK ON A REPAIR. THE EXCAVATION WAS MONITORED THROUGHOUT THE NIGHT. ONCE CRUDE OIL WAS ACROSS THE SECTION THE LINE WAS SHUT DOWN AND A PLIDCO SLEEVE INSTALLED. ONCE THE PIPELINE WAS EXPOSED, MONITORING DID NOT SHOW DETECTABLE LEVELS OF ORGANIC GASES, WHICH IS AN INDICATION OF NGL. THIS COUPLED WITH VISUAL OBSERVATIONS, LACK OF A VAPOR CLOUD AND NO FROZEN CONDENSATION, THE AMOUNT OF NGL RELEASED IS BELIEVED TO BE MINIMAL. THE WELD WAS INSPECTED USING VISUAL INSPECTION, MAGNETIC PARTICLE INSPECTION, AND ULTRASONICS (UT), BOTH SHEAR WAVE AND FAST. IT WAS DETERMINED THAT THE PINHOLE WAS A RESULT OF POROSITY PRESENT IN THE WELD FROM ORIGINAL CONSTRUCTION.