HOLLY ENERGY PARTNERS - OPERATING, L.P.

Incident Narrative

ON THE EVENING OF MONDAY, JUNE 3, 2019, A LEAK OF DIESEL FUEL OCCURRED ON A FILTER POT ON A MANIFOLD ON THE GROUNDS OF HOLLY ENERGY PARTNERS PD TERMINAL IN EL PASO, TEXAS. THE LEAK OCCURRED DURING A SHIPMENT OF DIESEL TAKING PLACE AT THE TERMINAL AND ORIGINATED FROM THE FILTER POT. THE LEAK OCCURRED IN A CONTAINMENT AREA AROUND THE MANIFOLD AND WAS CONTAINED TO TERMINAL PROPERTY. TERMINAL PERSONNEL FIRST DISCOVERED THE LEAK AT APPROXIMATELY 19:36 MDT AND WITHIN A FEW MINUTES SHUT DOWN A PUMP AND CLOSED A VALVE AT THE FACILITY TO STOP THE LEAK. TERMINAL PERSONNEL CALLED FOR A VAC TRUCK AT APPROXIMATELY 19:40, A TRUCK ARRIVED BY 20:30 AND CONTRACTORS COMPLETED REMOVAL OF DIESEL FROM THE GROUND BY 23:58. AT 20:11, TERMINAL PERSONNEL WERE ABLE TO MEASURE THE EXTENT OF THE DIESEL POOLED ON THE GROUND AND HEP CALCULATED AN ESTIMATED SPILL VOLUME. HEP MADE AN NRC REPORT AT 21:10. HEP EXAMINED THE FILTER POT AND DETERMINED THAT A VITON O-RING FAILED, CAUSING THE LEAK. EARLY INDICATIONS ARE THAT THERMAL STRESS ON THE O-RING MAY HAVE CAUSED IT TO FAIL. HEP IS INVESTIGATING THE FAILURE AND WILL PROVIDE UPDATES AS NECESSARY. UPDATE: OCTOBER 11, 2019 ON FURTHER INVESTIGATION OF THE FILTER POT, THE VITON O-RING, SECURITY CAMERA FOOTAGE THAT CAPTURED THE FILTER POT AT THE TIME OF THE RELEASE, AND DISCUSSIONS WITH TERMINAL PERSONNEL, HEP HAS DETERMINED THE FOLLOWING: THE VIDEO RECORDING OF THE LEAK SHOWS THAT THE VITON O-RING WAS PUSHED OUT OF THE TOP OF THE FILTER POT APPROXIMATELY 10 MINUTES PRIOR TO THE TERMINAL OPERATOR STARTING THE PUMP FOR A DELIVERY. THERE WAS AN INITIAL SPRAY, THEN A SMALL TRICKLE. APPROXIMATELY 10 MINUTES LATER THE TERMINAL OPERATOR STARTED THE PUMP FOR THE DELIVERY AND AN ADDITIONAL SPRAY ENSUED FROM THE COMPROMISED FILTER POT AND DID SO UNTIL THE TERMINAL OPERATOR WAS DOING NORMAL WALK THROUGH OF AREA OPERATIONS, IDENTIFIED THE LEAK AND THE PUMP WAS SHUT DOWN. THE FILTER O-RING INSTALLATION WAS FOUND TO BE COMPROMISED WHICH INCREASED THE PROBABILITY OF FAILURE. THE TOP LID OF THE FILTER POT IS HELD ON BY SIX BOLTS. UPON INVESTIGATION ONLY FIVE BOLTS WERE FOUND TO BE TIGHTENED. THE BOLT THAT WAS NOT TIGHTENED IS WHERE THE O-RING PUSHED OUT FROM BETWEEN THE LID AND THE BODY OF THE FILTER POT. AMBIENT TEMPERATURE SWINGS OF APPROXIMATELY 30F ON THE DAY OF THE RELEASE MAY HAVE INCREASED THE PRESSURE INSIDE THE FILTER POT AND ASSOCIATED PIPING AND, TOGETHER WITH THE LOOSE FILTER POT LID BOLT, MAY HAVE CAUSED THE O-RING TO PUSH OUT AND FAIL AT A RELATIVELY LOW PRESSURE. THE NEARBY THIRD PARTY OPERATOR TAKING DELIVERY OF DIESEL FROM THIS PART OF HEP'S SYSTEM REPORTED THAT THE LINE PRESSURE WAS APPROXIMATELY 134 PSIG AT THE TIME HEP'S PUMP WAS STARTED. THE MOP OF THIS PART OF THE SYSTEM WAS SET AT 285 PSIG. DURING THE INVESTIGATION HEP FOUND THAT THE FILTER POT WAS STAMPED WITH A 150 PSIG PRESSURE LIMIT, AND WAS THEREFORE THE PRESSURE LIMITING COMPONENT ON THIS PART OF THE SYSTEM. THE 134 PSIG PRESSURE OBSERVED DURING THE RELEASE SUGGESTS THAT PRESSURE DID NOT EXCEED 150 PSIG. TO MAINTAIN THE 285 PSIG MOP GOING FORWARD, HEP BLINDED OFF THE FILTER POT FROM THE SYSTEM. THIS PART OF THE SYSTEM IS PROTECTED BY A THERMAL RELIEF VALVE WITH A SET PRESSURE OF 275PSIG. THERE WAS NO EVIDENCE OF THE THERMAL RELIEF VALVE RELIEVING TO THE SUMP. THE THERMAL RELIEF VALVE WAS CHECKED FOR THE CORRECT SET PRESSURE OF 275 PSIG AND IT WAS FOUND TO BE OPERATING CORRECTLY AND SET PROPERLY.