HARVEST MIDSTREAM COMPANY

Incident Narrative

ON OCTOBER 15, 2018, A PIPE SPOOL USED FOR CHEMICAL INJECTION AT THE DILLEY STATION ON THE PEARSALL PIPELINE NEAR THE PIG LAUNCHER RUPTURED, RELEASING APPROXIMATELY 675 BARRELS OF CRUDE OIL. A THIRD-PARTY ROOT CAUSE ANALYSIS PERFORMED BY ELEMENTS MATERIAL TECHNOLOGY DETERMINED THAT THE CAUSE OF THE RUPTURE WAS OVERPRESSURE. THE PIPE SAMPLE DID NOT SHOW SIGNS OF ANY MATERIAL DEFECTS OR CORROSION. SIX DAYS PRIOR TO THE RUPTURE, ON OCTOBER 9, 2018, A CLEANING PIG WAS RUN THROUGH THE PEARSALL PIPELINE. FOLLOWING THAT PIGGING OPERATION, THE BYPASS VALVE (NORMAL MAINLINE BLOCK VALVE) WAS LEFT IN THE CLOSED POSITION, THE INLET VALVE (LAUNCHER BLOCK VALVE) WAS LEFT IN THE OPEN POSITION, AND THE LAUNCHER OUTLET VALVE WAS LEFT IN THE OPEN POSITION. PRODUCT WAS ABLE TO MOVE THROUGH THE SYSTEM WITH THE VALVES IN THIS CONFIGURATION BY FOLLOWING A FLOW PATH THROUGH THE LAUNCHER. HOWEVER, THE PIPE SPOOL DID NOT HAVE OVER PRESSURE PROTECTION BECAUSE THE BYPASS VALVE (NORMAL MAINLINE BLOCK VALVE) WAS NOT IN THE OPEN POSITION. PRESSURE BUILT UP IN THE PIPE SPOOL AS THE PUMP CONTINUED TO INJECT CHEMICALS, WHICH EVENTUALLY LED TO THE RUPTURE. DIRECT CAUSE-OVERPRESSURE; SYSTEM CAUSE-INADEQUATE HAZARD ANALYSIS PREVENTATIVE MEASURE TO KEEP FROM REOCCURRING THE CHEMICAL INJECTION POINT WAS MOVED TO AN ALTERNATE LOCATION ELIMINATING THE POSSIBILITY OF OVER PRESSURIZATION. ALL CHEMICAL INJECTION LOCATIONS ON THE PEARSALL PIPELINE HAVE BEEN EVALUATED TO CONFIRM OVERPRESSURE PROTECTION IS ADEQUATE IN THE EVENT A VALVE IS LEFT CLOSED.