ONEOK NGL PIPELINE, LLC

Incident Narrative

LOCATION WAS IDENTIFIED AS 80% EXTERNAL CORROSION IN ILI PRELIMINARY REPORT RECEIVED ON 12/16/2015. UPON DISCOVERY, ONEOK REDUCED THE MAXIMUM OPERATING PRESSURE OF THE PIPELINE TO 703 PSIG, 80% OF HIGHEST PRESSURE EXPERIENCED AT THE LOCATION OF THE ANOMALY SINCE 60 DAYS PRIOR TO THE DATE OF THE ILI RUN. INSPECTION CREW WAS MOBILIZED AND EXCAVATION BEGAN 12/17/2015. UPON COMPLETING THE EXCAVATION, FIELD CREW BEGAN TO CLEAN THE PIPE IN SEARCH OF THE ANOMALY, AS THEY WERE WIRE BRUSHING THE PIPE; PRODUCT BEGAN TO SEEP FROM THE LINE. NO INDICATIONS OF A RELEASE WERE OBSERVED PRIOR TO WIRE BRUSHING THE PIPE. A MECHANICAL CLAMP WAS IMMEDIATELY INSTALLED ON THE PIPELINE AND THE LINE REMAINED IN-SERVICE AT THE REDUCED RATE WITH PERSONNEL CONTINUOUSLY MONITORING THE SITE UNTIL THE PRODUCT COULD BE DISPLACED WITH NITROGEN. AT APPROXIMATELY 09:30 ON 12/18/2015 ONEOK COMPLETED THE NITROGEN PURGE AND THE PIPELINE WAS SHUTDOWN. ONEOK REMOVED THE SECTION OF PIPE CONTAINING THE DEFECT AND REPLACED WITH NEW PRETESTED PIPE. THE PIPELINE WAS RETURNED TO SERVICE ON 12/20/2015 AT 23:00.