TC OIL PIPELINE OPERATIONS INC

Incident Narrative

A TRANSCANADA EMPLOYEE WAS PERFORMING A WALK OF THE YARD AND NOTICED PRODUCT ON THE GRAVEL BENEATH A VALVE. IT WAS DETERMINED THAT THE PACKING FAILED ON THE MOV-2201, A RISING STEM GATE VALVE, CAUSING PRODUCT TO OVERFLOW THE SITE GLASS AND SPILL TO THE GROUND. THE GATE VALVE WAS IN THE CLOSED POSITION AT THE TIME OF DISCOVERY, AND WAS NOT BEING OPERATED. THAT SEGMENT OF PIPELINE WAS COMMISSIONED AND PUT INTO SERVICE ON 22 JAN, 2014. SUBSEQUENTLY, ONLY ONE INSPECTION WAS DUE, AND COMPLETED, PRIOR TO THE RELEASE. THAT IN-DEPTH INSPECTION (M6) WAS COMPLETED 22 APR, 2014. IMMEDIATELY ON DISCOVERY, THE OIL CONTROL CENTRE WAS NOTIFIED AND ISOLATED THE LINE INTO THE TERMINAL. FOLLOWING INITIAL CLEANUP ACTIVITIES, VALVE MAINTENANCE INJECTED TIGER PACK PACKING COMPOUND, AND INSTALLED TUBING ON VALVE STEM CAVITY DRAIN PORT TO CONFIRM SEAL WAS WORKING. MOV-2201 WAS CYCLED SEVERAL TIMES; VERIFIED VALVE STEM CAVITY PACKING WAS NOT LEAKING AT LOW LINE PRESSURE. LINE RETURNED TO NORMAL OPERATING PRESSURE 34 HOURS LATER; MOV-2201 WAS OBSERVED FOR 52 HOURS WITHOUT ISSUE. AN INTERNAL INCIDENT INVESTIGATION WAS CONDUCTED AND CONCLUDED THAT THE RESULTING SEEPAGE WAS FROM TORRENTIAL RAINS ENTERING THROUGH THE ACTUATOR, PUSHING OUT RESIDUAL OIL FROM THE EXTENSION OUT TO ATMOSPHERE. THIS PARTICULAR VALVE WAS THE LAST MOV ON SITE TO GET THE RAIN COVER, SO WATER MAY HAVE ACCUMULATED IN THE EXTENSION.