MARATHON PIPE LINE LLC

Incident Narrative

WHILE PERFORMING A FACILITY INSPECTION, AN AREA TECHNICIAN DISCOVERED CRUDE OIL ON TOP OF STANDING WATER WITHIN A VAULT FOR VALVE R1 AT MPL'S BROWNSVILLE STATION. VALVE R1 IS AN OUT-OF-SERVICE VALVE THAT HAD BEEN USED IN PREVIOUS SERVICE OF THE LINE. BECAUSE THE VALVE VAULT DRAINS TO A NEARBY RETENTION POND LOCATED WHOLLY WITHIN FACILITY PROPERTY, CRUDE OIL WAS ALSO DISCOVERED ON TOP OF THE POND. IN RESPONSE TO DISCOVERY, THE ASSOCIATED PIPELINE SYSTEM WAS IMMEDIATELY SHUT DOWN. PLANS WERE IMMEDIATELY DEVELOPED TO IMPLEMENT A STOPPLING PLAN TO REMOVE VALVE R1. THE LINE WAS PERMANENTLY REPAIRED BY REMOVING VALVE R1 AND INSTALLING A BLIND. THE RELEASE WAS TOTALLY CONTAINED ON OPERATOR CONTROLLED PROPERTY AND WAS PROMPTLY CLEANED UP. MPL'S INVESTIGATION REVEALED THAT THE VALVE PLUG AT THE OBSERVATION HOLE BETWEEN THE PRIMARY AND SECONDARY O-RING STEM SEALS CONTAINED A SMALL HOLE WHICH PROVIDED A RELEASE POINT FOLLOWING FAILURE OF THE PRIMARY SEAL. IT IS BELIEVED THAT THESE TYPES OF VALVES (12"" M&J EXPANDING GATE VALVE, MANUFACTURED 1967) CONTAINED A HOLE IN THE PLUG BY DESIGN, MOST LIKELY FOR STEM SEAL FAILURE OBSERVATION. UPDATED WITH FINAL COSTS.