ENBRIDGE STORAGE (CUSHING) L.L.C.

Incident Narrative

ON FEBRUARY 14, 2016 AT 8:05 CDT, AN OPERATION TECHNICIAN DISCOVERED PRODUCT ON THE GROUND BY THE NORTH MIXER AT TANK 2229 WHILE PERFORMING A ROUTINE INSPECTION. THE SOURCE OF THE RELEASE WAS COMING FROM A STEADY STREAM OF PRODUCT LEAKING BY THE NORTH MIXER (CG-311-MX-2229A), WHICH WENT INTO THE TANK DIKE DRAIN, BUT WAS FULLY CONTAINED IN THE BERM. THE NATIONAL RESPONSE CENTER (NRC) WAS NOTIFIED ON FEBRUARY 14, 2016 AT 10:03 CDT (REPORT #1140431), AS WELL AS THE OKLAHOMA CORPORATION COMMISSION (OCC). IT WAS DETERMINED THAT THE LEAK WAS DUE TO A MIXER SEAL FAILURE AS A RESULT OF THE MIXER PROPELLERS COMING INTO CONTACT WITH THE EXTERNAL FLOATING ROOF. THIS CONTACT TOOK PLACE DURING A SERVICE CHANGE ON FEBRUARY 9, 2016 WHILE LANDING THE ROOF AT APPROXIMATELY 23:14 CDT. THE PRODUCT IN TANK 2229 WAS TRANSFERRED INTO OTHER TANKS AND ALL REMEDIAL PRODUCT AND GROUND CLEAN-UP EFFORTS WERE COMPLETED ON FEBRUARY 19, 2016 AT 17:00 CDT. A BLIND WAS INSTALLED ON THE MIXER FLANGE AND THE TANK WAS PUT BACK INTO SERVICE ON FEBRUARY 18, 2016 AT 23:40 CDT. THE BASIC ROOT CAUSE OF THE RELEASE WAS DETERMINED TO BE A FAILURE TO ASSESS MIXER COMPATIBILITY WITH FLOATING TANK ROOF CONFIGURATION PRIOR TO INSTALLATION. AS A RESULT, THE MIXER WAS PUT INTO SERVICE WITHOUT VERIFYING THE CLEARANCES BETWEEN THE PROPELLERS AND THE TANK FLOATING ROOF. IN ORDER TO PREVENT REOCCURRENCE, TECHNICAL SERVICES WILL BE TRAINING PERSONNEL TO HAVE ENGINEERING ASSESS ANY FUTURE NON LIKE-TO-LIKE MIXER REPLACEMENTS. TECHNICAL SERVICES WILL ALSO BE CONDUCTING A REVIEW OF CURRENT MIXER EQUIPMENT WITHIN THE CUSHING TERMINAL AREA AS ANOTHER PREVENTATIVE MEASURE.