BP USFO/LOGISTICS

Incident Narrative

DUBUQUE TANK 12 WAS TAKEN OUT OF SERVICE FOR AN API 653 INSPECTION IN LATE OCTOBER, 2017. THE API 653 INSPECTION WAS PERFORMED DURING NOVEMBER OF 2017, AND REPAIRS COMMENCED IN DECEMBER OF 2017. THE REPAIRS WERE COMPLETED JULY 19, 2018, AND THE TANK RETURNED TO SERVICE BY THE END OF JULY 2018. ON 06 AUGUST 2018 @09:10 A LOCAL OPERATIONS TECHNICIAN WAS PERFORMING HIS MORNING ROUNDS. AS THE TECHNICIAN APPROACHED TANK 12 THE SMELL OF DIESEL WAS DETECTED. UPON FURTHER EXAMINATION PRODUCT WAS OBSERVED TO BE EMANATING FROM BELOW THE TANK BOTTOM. THE TECHNICIAN CONTACTED THE TERMINAL MANAGER IMMEDIATELY. A GRAVITY TRANSFER TO TANK 13 WAS STARTED AND THE CONTROL CENTER COMMENCED SHIPPING OUT OF TANK 12 TO EVACUATE PRODUCT. TANK 12 WAS EMPTY ON 07 AUGUST 2018 @ 16:35. THE METALLURGICAL ANALYSIS DETERMINED THAT A HEAT AFFECTED ZONE WEAKENED TANK FLOOR PLATE WELDS. THE GEOTECHNICAL INVESTIGATION SUGGESTS SEEPAGE THROUGH THE CONTAINMENT WAS POTENTIALLY CAUSED BY: 1) EXISTING SUBSURFACE UTILITY LINE PENETRATIONS. 2) SEEPS NEAR THE BOTTOM OF THE DIKES. 3) DESICCATION CRACKING OF THE BERM CLAYS DURING EXTENDED DRYING PERIODS. 4) ZONES OF HIGHER PERMEABILITY MATERIALS IN THE FLOOR OR FOUNDATION SOILS UNDER THE BERMS. WORK IS UNDERWAY TO ALLEVIATE THE SEEPAGE FROM THE DIKE.