MARATHON PIPE LINE LLC

Incident Narrative

FORT LARAMIE STATION WAS DOWN FOR CONSTRUCTION AND MAINTENANCE ACTIVITIES ASSOCIATED WITH FLOW REVERSAL PROJECT. MAINLINE PIPE ASSOCIATED WITH THIS PORTION OF THE SYSTEM WAS PURGED AND IDLED FOR PROJECT BETWEEN PIG TRAPS. UNDERGROUND STATION PIPE BETWEEN ORIGINAL PIG TRAP LOCATION AND NEW TRAP LOCATION HAD NOT BEEN COMPLETELY PURGED. STATION PIPE WAS OPEN TO ATMOSPHERE AT ORIGINAL AND NEW TRAP LOCATIONS AT TIME OF ACCIDENT. CONTRACTORS PERFORMING WORK AT NEW TRAP LOCATION WERE EXPERIENCING ELEVATED LEL AND BENZENE PRIOR TO ACCIDENT. OPERATOR PERSONNEL RECOMMENDED USING COPPUS FAN TO GET AIR MOVEMENT THROUGH THE PIPE. CONTRACTOR INSTEAD INSTALLED DRESSER COUPLING AND CAP WITH 1-INCH THREAD-O-LET TO THE STATION PIPE. AN AIR COMPRESSOR WAS ATTACHED TO THIS CAP AND USED IN ATTEMPT TO PUSH VAPORS FROM WORKSITE. WHILE PUSHING AIR TO CONTROL VAPORS, CRUDE OIL WAS INADVERTENTLY PUSHED THROUGH THE STATION PIPE. PROJECT INSPECTOR INITIALLY FOUND APPROXIMATELY 4.55 BBL OF OIL IN EXCAVATION AT THE ORIGINAL TRAP SITE. VISIBLE SOIL CONTAMINATION AND FREE PRODUCT WERE REMOVED ON THE DAY OF THE ACCIDENT. ONGOING MONITORING OF THE SITE IDENTIFIED GROUNDWATER AND CRUDE INGRESS INTO THE EXCAVATION. GROUNDWATER SKIMMING PERFORMED TO REMOVE REMAINING OIL. TOTAL RECOVERED VOLUME OF 15 BBL.