MARATHON PIPE LINE LLC

Incident Narrative

ON MAY 16, 2022 AN MPL MAINTENANCE CREW WAS PERFORMING EXCAVATION ON THE BAGGS-WAMSUTTER MAINLINE SEGMENT OF THE ILES-WAMSUTTER CRUDE SYSTEM IN RESPONSE TO AN ANOMALY DISCOVERED DURING AN IN-LINE INSPECTION. AT 13:00, THE CREW'S AIR MONITORING EQUIPMENT BEGAN TO DETECT HYDROCARBON VAPORS IN THE EXCAVATION. CREWS IMMEDIATELY MADE INTERNAL NOTIFICATIONS REGARDING THE DETECTION OF HYDROCARBON VAPORS. CREWS CONTINUED TO EXCAVATE, AND ONCE THE SEGMENT OF PIPE WAS EXPOSED, A BUBBLE ON THE COATING WAS IDENTIFIED AT THE 6 O'CLOCK POSITION ON THE PIPE. WHEN THE COATING WAS REMOVED, A DRIP STARTED TO FORM FOLLOWED BY MISTING OF OIL. AT 17:55, THE PIPELINE SEGMENT WAS SHUT DOWN. A BOLT-ON SLEEVE WAS INSTALLED TO REPAIR THE PIPE. AFTER THE REPAIR, FURTHER WORK HAS CONTINUED TO DETERMINE THE EXTENT OF THE IMPACTED SOIL AND CONFIRM THE SOURCE. BASED UPON THE VERY SMALL AMOUNT OF PRODUCT OBSERVED UPON EXPOSING THE PIPE, IT WAS NOT CLEAR WHETHER THE SURROUNDING SOIL HAD BEEN IMPACTED BY THE DISCOVERED LEAK, OR WHETHER IT WAS FROM ANOTHER HISTORICAL SOURCE (I.E, NEARBY ABANDONED LINE). THE WORK HAS INCLUDED VARIOUS POTHOLES, EXPOSING THE PIPE FURTHER, AND DIGGING BELOW THE PIPELINE. ALTHOUGH NO VISIBLE SOIL CONTAMINATION HAS BEEN FOUND, A PETROLEUM ODOR CONTINUES TO BE PRESENT. SOIL SAMPLES HAVE BEEN TAKEN TO DETERMINE THE LEVEL OF IMPACT. ON JUNE 10TH, FOLLOWING RECEIPT OF LAB RESULTS IT WAS DECIDED TO CONTINUE EXCAVATION TO DETERMINE THE EXTENT OF THE IMPACTED SOIL. WITH THE ADDITIONAL EXCAVATIONS PLANNED, IT HAS BEEN DETERMINED THAT THE COSTS WILL LIKELY EXCEED THE $50,000 THRESHOLD FOR NRC REPORTING. AUGUST 30, 2022 UPDATE - THE INTERNAL INVESTIGATION HAS BEEN COMPLETED AND THE APPARENT CAUSE WAS UPDATED TO CORROSION FAILURE WITH SUB-CAUSE OF INTERNAL CORROSION, RESULTING IN UPDATES TO ALL OF PART G AND ADDITIONAL QUESTIONS TO ANSWER IN PART J. AS PREVIOUSLY NOTED, THE REPAIR HAS BEEN COMPLETED.