NUSTAR PIPELINE OPERATING PARTNERSHIP L.P.

Incident Narrative

AT APPROXIMATELY 11:50 AM ON JUNE 10, 2022, A LANDOWNER CALLED THE CONTROL CENTER AND REPORTED FUEL ON THE GROUND AND A DIESEL ODOR IN A WET AREA WHILE PLANTING CORN. NUSTAR EMPLOYEES WERE IMMEDIATELY DISPATCHED TO THE AREA TO INVESTIGATE. THIS IS KNOWN AS LINE 5, WHICH IS A 6-INCH INTERSTATE REFINED PRODUCTS LINE. THE LINE, ALREADY SHUT DOWN PER SCHEDULE, WAS IMMEDIATELY BLOCKED IN. THE LEAK WAS CONFIRMED BY LOCAL PERSONNEL ONSITE UPON ARRIVAL AT 13:20 ON JUNE 10, 2022. AGENCY NOTIFICATIONS WERE MADE, AND REPAIR AND CLEANUP CREWS WERE DISPATCHED. THE LINE WAS EXCAVATED ON THE MORNING OF JUNE 11, 2022, AND A PINHOLE WAS FOUND, THE APPARENT RESULT OF A LIGHTNING STRIKE. THE METALLURGICAL ANALYSIS SUPPORTED OUR INITIAL CONCLUSION: ""THE LEAK AND ASSOCIATED CRATER CONTAINED FEATURES CONSISTENT WITH A HIGH ENERGY, SHORT TIMESCALE EVENT THAT RESULTED IN MELTING AND RE-SOLIDIFICATION. HEAT-AFFECTED ZONES CONTAINING A NARROW BAND OF MARTENSITE AND ADJACENT HEAT-AFFECTED ZONES WERE OBSERVED STARTING AT THE OUTER SURFACE AND GOING ALL THE WAY DOWN TO THE HOLE, WHICH CREATED THE LEAK PATH. BASED ON THE HOLE'S CHARACTERISTICS, IT APPEARS TO BE A PERFORATION THAT WAS APPARENTLY CREATED DURING THE HIGH ENERGY EVENT. THE EVENT COULD HAVE RESULTED FROM AN INADVERTENT ARC GENERATED BY A WELDING TOOL, OR A DISCHARGE AND ARCING BETWEEN THE PIPELINE AND A NEARBY CONDUCTOR, (E.G., CASING), DUE TO LIGHTNING. BASED ON ADDITIONAL INFORMATION PROVIDED BY NUSTAR, LIGHTNING STORMS HAD BEEN REPORTED PRIOR TO THE TIME THE LEAK WAS DISCOVERED, WHICH MAKES ARCING FROM NEARBY LIGHTNING STRIKES A LOGICAL ASSUMPTION AND THE MOST LIKELY CAUSE FOR THE HOLE THAT CAUSED THE LEAK."" THE LINE WAS REPAIRED AND RETURNED TO SERVICE AT 01:03 ON JUNE 13, 2022. WE SET UP A TEMPORARY RECOVERY SYSTEM AT THE LEAK SITE, AND WE RECLAIMED AN ESTIMATED 102 BARRELS OF FREE PRODUCT FROM THE SITE.