EXPLORER PIPELINE CO

Incident Narrative

ON FEBRUARY 7, 2019 LOCAL EXPLORER PERSONNEL DETERMINED THAT A THREADED FITTING ASSOCIATED WITH A PRESSURE TRANSMITTER SENSE LINE HAD DEVELOPED A LEAK. DUE TO HEAVY RAINS A LIGHT SHEEN WAS IDENTIFIED DIRECTLY IN FRONT OF THE DITCH AT THE TANK FARM. THE DITCH IN FRONT OF THE TANK FARM IS TYPICALLY A DRY DITCH. THE SHEEN WAS APPARENTLY CAUSED FROM THE CASING HEAD/NATURAL GASOLINE. ABSORBENTS WERE UTILIZED, AS WELL AS AN OSRO WAS NOTIFIED TO RESPOND. VERY LITTLE CASING HEAD/NATURAL GASOLINE WAS RECOVERED, AS MOST EVAPORATED. THE NRC WAS NOTIFIED DUE TO SHEEN IN THE DITCH IN FRONT OF TANK FARM. NRC NUMBER 1237080 WAS PROVIDED FOR INITIAL CALL, AND NRC NUMBER 1237268 WAS PROVIDED FOR THE 48 HOUR UPDATE. THE THIRD-PARTY FAILURE ANALYSIS AND ROOT CAUSE REPORT INDICATED THE FRACTURE WAS DUE TO DUCTILE OVERLOAD APPLIED VIA A BENDING MOMENT TO THE BURIED ONE-HALF INCH SCHEDULE 80 PRESSURE TRANSMITTER SENSING PIPE THAT WAS THREADED INTO AN ELBOW. THE POTENTIAL SOURCE OF THE BENDING MOMENT APPEARS TO BE FROM A FREEZE THAW CYCLE TO THE BURIED ONE-HALF INCH PRESSURE TRANSMITTER PIPE. THE FAILURE ANALYSIS FURTHER INDICATES THE FAILURE WAS MECHANICAL IN NATURE. THE OVERALL APPEARANCE OF THE FRACTURE SURFACE AND SURFACE MORPHOLOGY AS VIEWED IN THE SEM INDICATE THAT THE CRACK WAS ALONG THE OD SURFACE IN A THREAD ROOT. NO INDICATIONS WERE OBSERVED TO SUGGEST THAT CORROSION DAMAGE, STRESS CORROSION CRACKING (SCC), OR HYDROGEN EMBRITTLEMENT (HE) DAMAGE ISSUES WERE ACTIVE OR SIGNIFICANT CONTRIBUTORS TO THE OVERALL FAILURE MECHANISM. REPLACEMENT PIPING WAS INSTALLED ABOVE GRADE TO ELIMINATE THE POTENTIAL DUCTILE PRESSURE APPLIED WITH THE FREEZE THAW CYCLE FOR PRESSURE SENSING PIPE.