ENBRIDGE HOLDINGS (GRAY OAK) LLC

Incident Narrative

ON MAY 9, 2023, AT APPROXIMATELY 10:38 AM CDT A RELEASE WAS DISCOVERED AT THE WINK TERMINAL IN THE BOOSTER PUMP AREA. THE CONTROL CENTER WAS IMMEDIATELY NOTIFIED, AND THE LINE WAS SHUT DOWN AND WINK TERMINAL WAS ISOLATED UNTIL THE SOURCE OF THE RELEASE COULD BE DETERMINED. ENBRIDGE PERSONNEL AND CONTRACTORS WERE MOBILIZED TO THE SITE FOR CLEAN UP AND EXCAVATION TO IDENTIFY THE SOURCE. APPROXIMATELY 4 BARRELS OF CRUDE OIL WAS RELEASED AND CONTAINED WITHIN THE TERMINAL FACILITY. THE NRC WAS NOTIFIED ON MAY 9, 2023, AT 12:51 PM CDT (NRC# 1366778) WHEN IT WAS DETERMINED THAT THE COSTS WOULD EXCEED THE NRC REPORTING THRESHOLD. A 48-HOUR UPDATE TO THE NRC WAS MADE ON MAY 11, 2023, AT 10:13 AM CDT (NRC# 1366960). THE SOURCE OF THE RELEASE WAS IDENTIFIED AS A 16"" RECIRCULATION LINE IN THE BOOSTER PUMP MANIFOLD. THE SECTION OF PIPE WAS SLEEVED AND RETURNED TO SERVICE. ON JUNE 23, 2023, THE AFFECTED SECTION OF PIPE WAS REMOVED AND SENT TO A THIRD-PARTY FOR A METALLURGICAL ANALYSIS. AFTER FURTHER INVESTIGATION THE CAUSE OF THE RELEASE WAS DETERMINED TO BE DUE TO INTERNAL CORROSION PITTING ON THE BOTTOM SIDE OF THE RECIRCULATION LINE. THE RESULTS OF THE ANALYSIS INDICATE THAT THE INTERNAL CORROSION OBSERVED ON THE PIPE OCCURRED DUE TO MICROBIOLOGICALLY INFLUENCED CORROSION THAT WAS ACCELERATED BY THE HYPERSALINE CONDITIONS AND PRESENCE OF OXYGEN. SITE REMEDIATION PROCEEDED UNTIL EARLY AUGUST 2023, WITH CONTAMINATED SURFACE SOIL BEING REMOVED FROM AROUND THE BOOSTER PUMP AREA. SEVERAL ACTION PLANS HAVE BEEN CREATED TO ENHANCE INTEGRITY MANAGEMENT ACTIVITIES ON SIMILAR PIPE SEGMENTS AT OTHER FACILITIES ON THE GRAY OAK SYSTEM.