UNEV PIPELINE, LLC

Incident Narrative

ON AUGUST 21, 2023, AT APPROXIMATELY 8:30 A.M. MST, LOCAL OPERATING PERSONNEL ARRIVED ONSITE TO PERFORM WORK AT THE LYNNDYL VALVE STATION ALONG THE UNEV PIPELINE SYSTEM. UPON ARRIVING, THEY OBSERVED SOIL STAINING THAT HAD EXTENDED A FEW FEET BEYOND THE STATION'S FENCE LINE. PERSONNEL IMMEDIATELY INFORMED THEIR SUPERVISOR AND THE HEP CONTROL CENTER, THEN PROCEEDED TO MANUALLY EXCAVATE THE SATURATED SOIL TO IDENTIFY THE SOURCE OF THE RELEASE. BY APPROXIMATELY 4:00 P.M. MST, PERSONNEL HAD COMPLETED THE EXCAVATION, REACHING A DEPTH OF APPROXIMATELY 12 INCHES, AN ADDITIONAL 4 INCHES BEYOND THE STAINED SOIL AREA. THEY THEN CONDUCTED SPILL CALCULATIONS FOR THE AFFECTED AREA, ESTIMATING A RELEASE OF APPROXIMATELY 2 BARRELS OF MIXED REFINED PRODUCT (DIESEL AND GASOLINE). AT THIS TIME, PERSONNEL ALSO WERE ABLE TO CONFIRM THAT THERE WAS NO ONGOING LEAK. AFTER REACHING THIS DETERMINATION AND CONSULTING WITH AREA SUPERVISION, PERSONNEL BELIEVED THAT THE SATURATED SOIL MAY HAVE BEEN DUE TO A PRIOR NON-REPORTABLE RELEASE AT THE LYNNDYL STATION ON JULY 10, 2023. THIS INCIDENT WAS A RESULT OF A FAILURE OF A ""PUCK-STYLE"" BLOCK COMING OFF OF THE PRESSURE TRANSMITTER ON THE MAINLINE. THIS RELEASE GENERATED A FINE MIST, WHICH SETTLED ON ROCKS AND SOIL WITHIN THE STATION'S FENCE LINE. AT THE TIME OF THE JULY 10 RELEASE, PERSONNEL ESTIMATED A VOLUME OF NO MORE THAN 2 GALLONS, LEADING TO INTERNAL NOTIFICATIONS AND AN EVENT ENTRY INTO HEP'S INCIDENT MANAGEMENT SYSTEM. FOLLOWING THIS EVENT, AND OVER THE PERIOD OF JULY 10 TO AUGUST 21, THE AREA EXPERIENCED SIGNIFICANT RAINFALL. DURING THESE WEATHER EVENTS, PERSONNEL PERIODICALLY INSPECTED THIS, AND OTHER AREA SITES, FOR SIGNS OF ANY NEW ISSUES ARISING FROM THE WEATHER. NO EVIDENCE OF ANY NEW RELEASES WERE DISCOVERED AT THIS SITE. IN RESPONSE TO THE RELEASE VOLUME OF APPROXIMATELY 2 BARRELS ON AUGUST 21, NOTIFICATIONS WERE MADE TO THE NATIONAL RESPONSE CENTER (NRC) AND THE UTAH DEPARTMENT OF ENVIRONMENTAL QUALITY (UDEQ). IT'S WORTH NOTING THAT, ALTHOUGH THE INITIAL NRC REPORT INDICATES A TIMESTAMP OF 16:04, THERE WAS AN APPROXIMATE HALF-HOUR DELAY BEFORE THE CALL WAS ACTUALLY ANSWERED. AS OF THIS REPORT, THE APPARENT CAUSE OF THE INITIAL, NON-REPORTABLE RELEASE ON JULY 10 IS BELIEVED TO BE THE FAILURE OF THE ""PUCK-STYLE"" BLOCK OFF OF THE PRESSURE TRANSMITTER. OPERATING PERSONNEL HAVE CONFIRMED, BY THE MANUFACTURER, THE CORRECT INSTALLATION OF THE TRANSMITTER AND ALL CONNECTING EQUIPMENT, LEADING THEM TO PRESUME THAT THE FAILURE WAS DUE TO A FLAWED DESIGN. PRESENTLY, THE FAILED PRESSURE TRANSMITTER (MANUFACTURED BY ROSEMOUNT) AND THE ""PUCK-STYLE"" BLOCK HAS BEEN REPLACED WITH A HONEYWELL-MANUFACTURED PRESSURE TRANSMITTER. UPDATE 9/13/2024 - HF SINCLAIR MIDSTREAM CONTRACTED TRC TO CONDUCT SITE REMEDIATION EFFORTS. IN COLLABORATION WITH THE UTAH DEPARTMENT OF ENVIRONMENTAL QUALITY (UDEQ), TRC DEVELOPED A COMPREHENSIVE REMEDIATION PLAN. THE PLAN WAS SUBMITTED TO UDEQ ON AUGUST 12, 2024, AND SUBSEQUENTLY APPROVED ON AUGUST 28. HF SINCLAIR MIDSTREAM IS CURRENTLY AWAITING A REVISED PROPOSAL FROM TRC, WITH REMEDIATION WORK SCHEDULED TO BEGIN IN THE COMING MONTHS.