MID - VALLEY PIPELINE CO

Incident Narrative

THE MORNING OF 03/16/21 THE CONSOLE 3 CONTROLLER HAD LONGVILLE TANKS 14 AND 10 OPEN TO EACH OTHER ACROSS THE A HEADER, AND TANK 14 OPEN TO WTG INBOUND. AT 10:54AM THE SCADA HI LEVEL ALARM CAME IN FOR TANK 14. AT 10:55AM, THE CONSOLE 3 CONTROLLER CLOSED THE VALVE TO TANK 14 ON THE HEADER, HOWEVER TANK 14 WAS STILL OPEN TO WTG INBOUND FLOW. DURING THIS TIMEFRAME, THE CONTROLLER SWEPT HIS SCREENS BUT UNFORTUNATELY OVERLOOKED THAT WTG WAS STILL DELIVERING INTO TANKAGE, AND BY CLOSING OFF T14 FROM T10 ON THE HEADER, THE LEVEL IN T14 BEGAN TO RISE FASTER. AT 11:11 THE INDEPENDENT HI-HI SWITCH ALARM CAME IN ON TANK 14, AND THE CONTROLLER IMMEDIATELY OPENED TANK 13 TO INBOUND WTG FLOW AND ISOLATED TANK 14. THE CONTROLLER THEN SPOKE WITH OPERATOR AT LONGVIEW AND TOLD HIM ABOUT THE HI-HI SWITCH ANNUNCIATION, BUT THAT THE TANK WAS ONLY READING IN THE SCADA HI LEVEL AREA. THE CONTROLLER OPENED TANKS 13 AND 14 ON THE HEADER AT 11:13AM TO HELP DRAW VOLUME OUT OF TANK 14. SHORTLY AFTER THAT AT 11:15AM, THE OPERATOR CALLED THE CONSOLE AND ADVISED THE CONTROLLER THAT THERE WAS A HOLE ON THE TOP SIDE OF THE TANK AND THAT OIL WAS COMING OUT OF THAT HOLE. APPROXIMATELY 25 GALLONS HAD LEAKED DOWN THE SIDE OF THE TANK. THE OPS MANAGER CALLED THE CONSOLE AND LET THEM KNOW THAT THERE WAS A STREAK OF OIL DOWN THE TANK, AND THAT THE SEALS WERE VISIBLE ABOVE THE SHELL, BUT THAT WE HAD NOT FLOATED THE ROOF AWAY. BY 7:00PM, THE LEVEL IN TANK 14 WAS DRAWN DOWN SLOWLY UNDER THE SUPERVISION OF THE FIELD AND RELEASED BACK INTO NORMAL SERVICE WITH APPROVAL FROM THE OPS MANAGER AND CONTROL ROOM MANAGER, AFTER AN INSPECTION DETERMINED THAT THERE HAD NOT BEEN ANY ROOF SEAL DAMAGE. PER THE CONTROL ROOM MANAGEMENT, NO IMPAIRMENT FROM DRUGS OR ALCOHOL WAS OBSERVED FROM THE CONTROLLER. THE CONTROL ROOM MANAGER WENT OVER THE PROCEDURES WITH THE CONTROLLER TO MAKE SURE THAT HE IS PAYING ATTENTION TO HIS SCREENS AND IS AWARE OF WHAT IS GOING ON.