ENBRIDGE STORAGE (CUSHING) L.L.C.

Incident Narrative

ON APRIL 9, 2021 AT APPROXIMATELY 5:00 AM CDT, AN OPERATIONS TECHNICIAN AT THE CUSHING TERMINAL DISCOVERED A MECHANICAL SEAL FAILURE AT BOOSTER PUMP 212-BP-3. AT THE TIME OF THE DISCOVERED RELEASE, THE PUMP WAS STATIC, BUT PRODUCT WAS VISIBLY LEAKING FROM THE PUMP CAN ONTO THE GROUND. AFTER DISCOVERY, THE CUSHING CONTROL CENTER RECEIVED A BOOSTER SEAL FAIL ALARM WHICH PROMPTED THE PUMP TO BE SHUT DOWN AND ISOLATED FROM THE SYSTEM. A VACUUM TRUCK WAS DISPATCHED TO RECOVER OIL THAT HAD LEAKED FROM THE SEAL FAILURE AND ALL CONTAMINATED SOIL WAS REMOVED FROM THE SITE. IT IS ESTIMATED THAT 20 GALLONS OF CRUDE OIL WAS RELEASED. THE SEAL WAS REPLACED AND THE PUMP WAS PLACED BACK INTO SERVICE. BOOSTER PUMP 212-BP-3 WAS LAST REFURBISHED IN 2019 AND INSTALLED COMPLETELY PREASSEMBLED BY THE PUMP VENDOR. THE PUMP IS ROUTINELY USED FOR EVACUATING TANK VOLUMES BELOW WORKING BOTTOMS UNTIL IT LOSES SUCTION (CAVITATES). PRIOR TO REMOVAL AND DISASSEMBLY OF THE MECHANICAL SEAL, IT WAS NOTED THE COLLAR OF THE SEAL WAS RESTING ON TOP OF THE SEAL GLAND WITH NO GAP. THE ABSENCE OF THIS GAP INDICATES A DECOMPRESSION OF THE MECHANICAL SEAL'S INTERNAL SPRINGS WHICH LARGELY NEGATES ANY SEALING POTENTIAL. ADDITIONALLY, THE SOCKET SCREWS WERE NOTABLY LOOSE WITH LITTLE TO NO TENSION ON THE SHAFT. WHILE THERE IS NO TORQUE SPECIFICATION IDENTIFIED FOR THE MECHANICAL SEAL COLLAR, BECAUSE THE PUMP WAS INSTALLED PREASSEMBLED BY THE PUMP VENDOR AND HAS BEEN ROUTINELY USED FOR THE LAST 18 MONTHS IT IS BELIEVED THE PUMP WAS INSTALLED IN GOOD WORKING ORDER. AN INTERNAL INVESTIGATION HAS IDENTIFIED THE CAUSE TO BE DUE TO EXTENDED CAVITATION (VIBRATION) OF THE PUMP CAUSING THE SOCKET SCREWS TO BACK OUT OF THE SEAL COLLAR, DECOMPRESS THE TENSION ON THE ROTATING AND STATIONARY SEAL FACES, AND RESULTED IN THE LOSS OF PRIMARY CONTAINMENT.