MARATHON PIPE LINE LLC

Incident Narrative

ON OCTOBER 20, 2017, MARATHON PIPE LINE FIELD PERSONNEL AND CONTRACT CREWS WERE ON-SITE AND IN THE PROCESS OF RECOMMISSIONING THE LINE FOLLOWING MAINTENANCE, WHEN A RELEASE OCCURRED. A THREAD-O-RING (TOR) COMPLETION PLUG WAS BLOWN OUT AT APPROXIMATELY 4:09 AM CST, WHILE COMPLETING A STATIC-PRESSURE TEST. AT APPROXIMATELY 5:11 AM CST, MPL DETERMINED THIS RELEASE WAS NRC REPORTABLE DUE TO IT STILL BEING ACTIVE AND THEREFORE, ESTIMATED CLEAN-UP AND REPAIR COSTS EXCEEDING THE $50,000 THRESHOLD. WHEN THE RELEASE OCCURRED, CREWS HAD TO RETREAT FROM THE AREA DUE TO SAFETY CONCERNS. ADDITIONALLY, SEVEN RESIDENCES WERE EVACUATED VOLUNTARILY, WHICH INCLUDED APPROXIMATELY TWENTY PEOPLE. THEREFORE, THE TOR ISOLATION VALVE AT THE SOURCE OF THE RELEASE CONTINUED TO BE INACCESSIBLE FOR APPROXIMATELY 12 HOURS, UNTIL PRECAUTIONS COULD BE TAKEN TO MAKE SAFE ENTRY TO THE RELEASE POINT TO CLOSE THE VALVE. TOTAL RELEASE VOLUME IS ESTIMATED AT 1,096 BARRELS. BOTH MPL EMPLOYEES AND CONTRACTOR PERSONNEL WERE DRUG TESTED. MPL EMPLOYEES EXPERIENCED A MISCOMMUNICATION WITH PAPERWORK AT THE CLINIC AND ALCOHOL TESTING WAS NOT COMPLETED. THE CAUSE OF THE RELEASE WAS DETERMINED TO BE A PLUG INSTALLATION FAILURE AS A RESULT OF THE CONTRACT EMPLOYEE NOT FOLLOWING THE PROCEDURE. THE INITIAL NRC REPORT #1193767 (AS NOTED IN PART A, QUESTION 6) WAS MADE ON OCTOBER 20, 2017, AT 5:47 AM CST. THE 48-HOUR UPDATE REPORT, #1193916, WAS MADE ON OCTOBER 21, 2017, AT 1:37 PM CST TO PROVIDE AN UPDATED VOLUME ESTIMATE. 12/14/17: PART A, QUESTION 14 - UPDATED OUR RESPONSE TO ""YES"". PART D, QUESTION 8E - UPDATED LONG-TERM REMEDIATION COSTS. 2/15/18: PART D, QUESTION 8 - UPDATED WITH FINAL COST ESTIMATES. PART H - UPDATED THE NARRATIVE WITH INVESTIGATION RESULTS.