NUSTAR PIPELINE OPERATING PARTNERSHIP L.P.

Incident Narrative

THE ODOR OF AMMONIA WAS DETECTED BY AN INDIVIDUAL DRIVING BY THE ROAD CROSSING DIRECTLY DOWN STREAM OF VALVE 6-9 AND CALLED NUSTAR EMPLOYEE AT 6:50 PM ON FRIDAY EVENING. THE EMPLOYEE CALLED HIS SUPERVISOR AND WAS INSTRUCTED TO GO CHECK IT OUT. THE NUSTAR EMPLOYEE ARRIVED AT 7:30 PM, AND VERIFIED THE LEAK AFTER A VISUAL OBSERVATION OF THE AREA. THE AFFECTED AREA WAS APPROXIMATELY 6FT IN DIAMETER WITH BUBBLING MOISTURE SHOWING WITHIN THE AREA OF THE LEAK. IT WAS DETERMINED THAT IT WAS IN THE AREA OF A STOPPLE TEE. THE ODOR WAS NOT WIDE SPREAD AND LIMITED TO THAT AREA. AN EMERGENCY ONE CALL WAS MADE AND THE MAINTENANCE CREW TRAVELED SUNDAY MORNING TO EXCAVATE AND REPAIR. THE RELEASE WAS CALCULATED BASED ON VISUAL OBSERVATION OF APPROXIMATELY 1 OUNCE PER MINUTE LEAK RATE. AN ESTIMATED 11.25 GALLONS WAS RELEASED WHICH EQUATES TO 57.8 POUNDS IN A 24 HOUR PERIOD. TWO OF THE FOUR SEGMENTS OF THE STOPPLE TEE WERE LEAKING. THE SEGMENTS WERE CAPPED AND WELDED SHUT. THE 8"" ANSI 600 STOPPLE TEE WAS MANUFACTURED BY TD WILLIAMSON. IT IS MODEL NUMBER ASME B31.8. THE SOIL WAS REMEDIATED AND TAKEN TO THE NUSTAR PUMP STATION NEAR HUFFTON, IA, AFTER VERBAL APPROVAL FROM IDNR. CORRECTION TO B-10 MADE ON 3-31-2016, SUPPLEMENTAL REPORT SUBMITTED. SKP