TESORO HIGH PLAINS PIPELINE COMPANY LLC

Incident Narrative

ON SEPTEMBER 29, 2013, TESORO HIGH PLAINS PIPELINE (THPP) PERSONNEL WERE NOTIFIED OF A POSSIBLE CRUDE OIL RELEASE FROM A PIPELINE APPROXIMATELY 9 MILES NORTH OF TIOGA, ND. LOCAL THPP PERSONNEL IMMEDIATELY NOTIFIED THE CONTROL CENTER WHICH SHUTDOWN THE PIPELINE. THPP RESPONSE PERSONNEL WERE DISPATCHED TO THE SITE AND FEDERAL AND STATE AUTHORITIES WERE NOTIFIED (I.E. NRC AND ND STATE RADIO). THE PIPELINE WAS EXCAVATED AND THE RELEASE SOURCE (A SMALL HOLE) WAS CLAMPED. A SUBSURFACE ASSESSMENT OF THE AFFECTED SOIL HAS ESTIMATED THE TOTAL SPILL VOLUME AT 20,600 BBLS. THE AFFECTED PIPE WAS REMOVED AND SENT TO A LABORATORY FOR METALLURGICAL ANALYSIS. THE REPORT FROM THE METALLURGICAL LABORATORY DETERMINED THAT THE HOLE RESULTED FROM AN ELECTRICAL DISCHARGE. THE LABORATORY ALSO DETERMINED THAT THERE WAS NO EVIDENCE OF CORROSION OR MECHANICAL DAMAGE. THE ROOT CAUSE ANALYSIS INVESTIGATION DETERMINED THE ELECTRICAL DISCHARGE WAS MOST LIKELY THE RESULT OF A LIGHTNING STRIKE. ALTHOUGH THE EXACT DATE OF THE LIGHTNING STRIKE IS UNKNOWN, THE INVESTIGATION CONCLUDED THAT IT MOST LIKELY OCCURRED BETWEEN JULY 29 AND AUGUST 9, 2013. PER PHMSA GUIDANCE, THIS REPORT IS BEING SUBMITTED AS A ""FINAL"" REPORT BECAUSE THE ACCIDENT RESPONSE CONSISTS OF ONLY LONG TERM REMEDIATION WHICH IS BEING CONDUCTED UNDER THE AUSPICES OF THE NORTH DAKOTA DEPARTMENT OF HEALTH.