TALLGRASS PONY EXPRESS PIPELINE, LLC

Incident Narrative

ON 12/18/2022 AT 11:20 A.M. MOUNTAIN TIME (LOCAL TIME), THE TALLGRASS OPERATIONS CONTROL CENTER (OCC) RECEIVED A PHONE CALL FROM A THIRD PARTY INDICATING THAT OIL WAS OBSERVED LEAKING AT YODER STATION ON THE 20"" PONY EXPRESS PIPELINE. THE PONY EXPRESS PIPELINE WAS SHUT DOWN AT THE TIME OF THE NOTICE. THE OCC BEGAN ISOLATING THE YODER STATION AT 11:21 A.M. MOUNTAIN TIME BY REMOTELY CLOSING VALVES UPSTREAM AND DOWNSTREAM OF THE STATION. OPERATIONS TECHNICIANS WERE DISPATCHED AND ARRIVED ONSITE AT 12:15 P.M. MOUNTAIN TIME TO ASSESS THE RELEASE. AS THE INITIAL ASSESSMENT OF THE RELEASE OCCURRED, COMPANY PERSONNEL DETERMINED THAT THE RELEASE MET THE NRC THRESHOLD AS DESCRIBED UNDER 49 CFR 195.52 DURING AN UPDATE CALL AT 3:30 P.M.. THE NRC CALL WAS MADE IMMEDIATELY FOLLOWING THE UPDATE CALL. THE SITE OF THE RELEASE WAS MAINLINE VALVE MLV-1100. UPON INITIAL ASSESSMENT IT APPEARS THAT THE ACTUATOR BROKE OFF OF MAINLINE VALVE MLV-1100 AND HIT A 1/2-INCH NIPPLE ON THE VALVE RELIEF TUBING, BREAKING THE TUBING AND RESULTING IN THE REPORTABLE RELEASE. MINIMAL OVERSPRAY IMPACTED NON-OPERATOR PROPERTY TO THE WEST OF THE STATION. THE EQUIPMENT IS BEING SENT TO A THIRD PARTY FOR METALLURGICAL ANALYSIS AND A SUPPLEMENTAL REPORT WILL BE SUBMITTED ONCE THE INVESTIGATION IS COMPLETE. WE ANTICIPATE THE INVESTIGATION MAY BE COMPLETED WITHIN 8-12 WEEKS. 10/09/2023 UPDATED PART B, QUESTION 10 FROM ORIGINATED ON OPERATOR-CONTROLLED PROPERTY, BUT THEN FLOWED OR MIGRATED OFF THE PROPERTY TO TOTALLY CONTAINED ON OPERATOR-CONTROLLED PROPERTY AS THE MINIMAL OVERSPAY, THAT WAS CLEANED UP AS PART OF THE INITIAL RESPONSE, DID NOT FLOW OR MIGRATE. UPDATED PART C QUESTIONS 3, 5, AND 6 TO MORE ACCURATELY REFLECT THE EQUIPMENT THAT FAILED. THE EQUIPMENT THAT FAILED WAS NOT THE DIRECT SOURCE OF THE LEAK BUT BROKE THE TUBING THAT RESULTED IN THE REPORTABLE RELEASE. CHANGED PART G APPARENT CAUSE TO G6-EQUIPMENT FAILURE. THE ACTUATOR FELL OFF THE VALVE ASSEMBLY. THIS WAS BECAUSE THE THRUST ADAPTOR PLATE FAILED DUE TO BRITTLE TENSILE OVERLOAD FAILURE CAUSED BY THE ACTUATOR OVER-TORQUING. THE ACTUATOR OVER-TORQUED DUE TO FAILED ELECTRONIC LIMIT AND THE ELECTRONIC LIMIT IS SET DURING THE FABRICATION/INSTALLATION PROCESS. TALLGRASS RE-CONFIRMED OVER-TORQUE LIMITS ON SIMILAR VALVE ASSEMBLIES IN DECEMBER 2022 TO PREVENT SIMILAR EVENTS IN THE FUTURE. IN ADDITION, TALLGRASS HAS SCHEDULED THE INSTALLATION OF A PHYSICAL OPEN/CLOSE LIMIT ON SIMILAR VALVE ASSEMBLIES AS A SECONDARY FAIL-SAFE TO THE ELECTRONIC LIMIT DURING FOURTH QUARTER 2023.