ONEOK NGL PIPELINE, LLC

Incident Narrative

AT APPROXIMATELY 10:46 AM ON 12/26/2020 ONEOK PIPELINE CONTROL WAS CONTACTED BY MEMBERS OF THE PUBLIC STATING THAT THEY HAD NOTICED BUBBLES IN STANDING WATER NEAR THE ONEOK PIPELINE AT 6650 N. SARA RD. IN OKLAHOMA CITY, OK. ONEOK DISPATCHED FIELD PERSONNEL TO THE LOCATION AND SHUTDOWN THE PIPELINE AT APPROXIMATELY 12:29 PM. PIPELINE CONTROL CONTINUED TO MONITOR THE PRESSURE ON THE PIPELINE AND AN EMERGENCY ONE-CALL WAS MADE TO NOTIFY OTHER OPERATORS IN THE AREA. ONCE ALL THE OTHER PIPELINE OPERATORS HAD DETERMINED THEIR PIPELINES TO BE CLEAR OF THE PROPOSED EXCAVATION LOCATION, ONEOK EXCAVATED THE LOCATION TO DETERMINE THE SOURCE OF THE BUBBLES AS THE SHUT-IN PIPELINE HAD NO INDICATION OF PRESSURE LOSS. ON 12/28/2020 AFTER EXCAVATING THE PIPELINE, ONEOK DISCOVERED AN ICE FORMATION ENCIRCLING THE PIPELINE AS THE SOURCE OF THE BUBBLES IDENTIFIED BY THE PUBLIC. UPON THIS DISCOVERY, AN NRC NOTIFICATION WAS MADE. ONEOK PROCEEDED TO PURGE THE PIPELINE OF HYDROCARBONS ON 12/29/2020 AND 12/30/2020. ON 12/30/2020 A SIX (6) FOOT SECTION OF PIPE WAS REMOVED AND REPLACED WITH PRE-TESTED PIPE. THE PIPELINE WAS RETURNED TO SERVICE ON 12/31/2020. THE SECTION OF PIPE REMOVED HAS BEEN SENT TO A THIRD PARTY FOR ANALYSIS TO DETERMINE THE CAUSE OF FAILURE. THE 48-HOUR NRC UPDATE (#1295232) WAS SUBMITTED ON 12/30/20 AT 12:35. UPDATE - 4/22/21: THE ANALYSIS OF THE LEAK LOCATION INDICATES THE RELEASE OCCURRED AT A DEFECT WITHIN THE GIRTH WELD. THE DEFECT IS CONSISTENT WITH A ""BURN-THROUGH"" DEFECT, IN THE WELD MADE DURING THE INITIAL CONSTRUCTION OF THE PIPELINE.