ONEOK NGL PIPELINE, LLC

Incident Narrative

ON 4/20/2017, ONEOK CREWS REMOVED THE PIG TRAP CLOSURE ASSEMBLY TO INSTALL A BARREL EXTENSION TO RECEIVE AN INLINE INSPECTION (ILI) TOOL ON THE ONEOK- CHICO PIPELINE LOCATED AT THE ENLINK- BRIDGEPORT FACILITY. THE ASSEMBLY (FLANGE WELDED TO THREAD ON CLOSURE DOOR) HAD BEEN UNBOLTED AND SET TO THE SIDE. AFTER RECEIVING THE TOOL, THE CLOSURE DOOR ASSEMBLY WAS RE-INSTALLED ON THE PIPELINE PIG TRAP, AT APPROXIMATELY 13:30, WITHOUT THE CLOSURE DOOR EVER BEING OPENED. THE PIG TRAP WAS PURGE WITH HYDROCARBONS AND RETURNED TO NORMAL SERVICE. AT APPROXIMATELY 17:30 ONSITE ENLINK OPERATIONS PERSONNEL CONTACTED THE ONEOK PIPELINE CONTROL CENTER TO NOTIFY OF VAPORS RELEASING FROM THE ONEOK CHICO PIPELINE PIG TRAP. ONEOK FIELD EMPLOYEES WERE DISPATCHED TO THE LOCATION AND ISOLATED THE PIG TRAP. ONEOK EMPLOYEE'S DISCOVERED THE O-RING ON THE PIG TRAP CLOSURE DOOR HAD FAILED AND ALLOWED PRODUCT TO ESCAPE. A NEW O-RING WAS INSTALLED AND THE PIG TRAP RETURNED TO SERVICE. ONEOK INLINE INSPECTION TOOL RECEIVING PROCEDURE HAS BEEN AMENDED TO INCLUDE THE INSPECTION OF THE O-RING ON THE EXISTING PIG TRAP DOOR, EVEN IF THE DOOR HAD NOT BEEN OPENED BUT THE CLOSURE ASSEMBLY WAS REMOVED TO RECEIVE THE ILI TOOL. 17/05/17 UPDATED PART C, #6 TO ""LEAK"" -- PER DIRECTION OF PHMSA - ALEX COLLETTI - NJ