MAGELLAN PIPELINE COMPANY, LP

Incident Narrative

PRODUCT WAS DISCOVERED IN THE IMPOUNDMENT AREA AROUND TANK 1201. OPERATIONS WERE HALTED, PRODUCT RECOVERY BEGAN AND THE TANK CONTENTS WERE TRANSFERRED PRIOR TO TO CLEANING THE TANK FOR ENTRY. AN INTERNAL INSPECTION DISCOVERED A PINHOLE LEAK IN THE TANK FLOOR PLATE. THE SECTION OF THE FLOOR PLATE CONTAINING THE LEAK FEATURE WAS CUT OUT AND SENT TO A LABORATORY FOR METALLURGICAL ANALYSIS. METALLURGICAL ANALYSIS DETERMINED THE LEAK WAS CAUSED BY A CORROSION PIT THAT INITIATED ON THE SOIL SIDE OF THE TANK FLOOR AND GREW THROUGH WALL RESULTING IN A LEAK PATH. THE ANALYSIS CONCLUDED THAT THE LIKELY CAUSE OF THE CORROSION WAS A COMBINATION OF LOCALIZED CATHODIC PROTECTION SHIELDING AND MICROBIALLY INFLUENCED CORROSION. FURTHER INVESTIGATION DETERMINED THE ROOT CAUSE OF THE ANOMALY GOING UNDETECTED DURING THE MOST RECENT API 653 INTERNAL INSPECTION WAS DUE TO THE CURVATURE OF THE FLOOR (SPHEROID) AND THE ABILITY OF THE SCANNER TO REMAIN AT A CONSISTENT HEIGHT NECESSARY FOR THE MFL FLOOR SCANNER SENSORS TO PROPERLY EVALUATE THE FLOOR THICKNESS. APPROXIMATELY 80 CUBIC YARDS OF IMPACTED SOIL ARE ANTICIPATED TO BE REMEDIATED. IN 2012 AN INSTANT OFF SURVEY WAS PERFORMED ON TANK 1201 IN KANSAS CITY. THE READINGS WERE: NORTH SIDE -1.130, SOUTH SIDE - 1.054, EAST SIDE -1.093 AND THE WEST SIDE -1.097, THE TEST LEAD READING WAS -1.135.