BRIDGER PIPELINE LLC

Incident Narrative

AT APPROXIMATELY 10:15 MST ON SATURDAY, JANUARY 17, 2015, THE BRIDGER PIPELINE LLC ""BRIDGER"" CONTROLLER WHO WAS OPERATING THE POPLAR LINE NOTICED A FLOW IMBALANCE ON HIS SCADA SCREEN AND BEGAN TO INVESTIGATE. THE CONTROLLER NOTIFIED THE FIELD PERSONNEL OF A POSSIBLE ACCIDENT AND HAD FIELD PERSONNEL CHECK METERS TO ENSURE THEY WERE OPERATING CORRECTLY. AT APPROXIMATELY 10:40 AM MST AN ALARM FOR A ""LEAK WARNING"" WAS RECEIVED. THE CONTROLLER NOTIFIED THE ON CALL CONTROL CENTER SUPERVISOR AND INFORMED HIM OF THE SITUATION THEY BEGAN TO SHUT IN THE LINE AND AN AERIAL PATROL BEGAN MONITORING THE LINE SEGMENT. A PRESSURE DROP TEST CONFIRMED THAT THE PROBLEM WAS BETWEEN THE NORTH BLOCK VALVE AND THE SOUTH BLOCK VALVE. MEANWHILE THE CONTROLLER, WORKING THROUGH THE LOCAL FIELD SUPERVISOR HAD FIELD PERSONNEL DISPATCHED TO THE LOCATION TO INVESTIGATE AS WELL AS OTHER DOWNSTREAM RIVER ACCESS POINTS. DUE TO THE CONSIDERABLE AMOUNT OF ICE ON THE RIVER IT WAS DIFFICULT TO ASCERTAIN WHETHER THERE HAD BEEN A RELEASE TO WATER. AT APPROXIMATELY 10:49 AM MST THE LINE WAS SHUTDOWN. AT 3:58 PM MST AN NRC REPORT WAS MADE TO INDICATE A POSSIBLE RELEASE TO WATER. NRC REPORT NUMBER 1105930. LOCAL AUTHORITIES AND THE MONTANA DEPARTMENT OF ENVIRONMENTAL QUALITY WERE NOTIFIED AND THEY NOTIFIED MUNICIPAL WATER UTILITIES OF THE POTENTIAL CRUDE RELEASE. AT FIRST LIGHT ON SUNDAY, JANUARY 18, 2015, BRIDGER DISCOVERED AN OIL SHEEN IN OPEN WATER ON THE YELLOWSTONE RIVER APPROXIMATELY THREE QUARTERS OF A MILE DOWNSTREAM FROM THE CROSSING AND 18 MILES DOWNSTREAM FROM THE PIPELINE CROSSING. BASED ON THE AERIAL REPORTS MADE TO BRIDGER, THE PREVIOUS NRC REPORT WAS UPDATED TO STATE THAT THERE WAS A RELEASE OF CRUDE OIL INTO THE YELLOWSTONE RIVER. THE NEW NRC REPORT NUMBER IS 1105969. THE RELEASE AMOUNT IS ESTIMATED AT ABOUT 758 BARRELS OF CRUDE OIL WITH 65 BARRELS RECOVERED. THERE HAVE BEEN NO SIGNS OF WILDLIFE OR SOIL IMPACT. THE ROOT CAUSE FAILURE ANALYSIS (RCFA) FOUND THE CAUSE OF THE ACCIDENT TO BE NATURAL FORCE DAMAGE AS THE RIVERBED SCOURED AT THE CROSSING LEAVING THE PIPELINE EXPOSED TO ADDITIONAL FORCES OF THE RIVER. ACCORDING TO THE RCFA VORTEX INDUCED VIBRATIONS (VIV) LIKELY DEVELOPED RESULTING IN ADDITIONAL STRESSES TO THE PIPELINE. THE ADDITIONAL STRESSES RESULTED IN A FATIGUE CRACK FORMING VERY QUICKLY. THE FATIGUE CRACK GREW TO FROM THE YELLOWSTONE RIVERBED SCOURING AWAY THE PIPELINE CROSSING. THE VIV RESULTED IN STRESSES TO THE PIPELINE AND A FATIGUE CRACK FORMED AT THE 11:05 O'CLOCK ORIENTATION. THE PIPELINE FAILED AFTER THE FATIGUE CRACK PROPAGATED. A DEPTH OF COVER SURVEY WAS COMPLETED IN 2011 AND 2012 AND BOTH INDICATED ADEQUATE COVER OVER THE PIPELINE CROSSING.