MARATHON PIPE LINE LLC
hazardous_liquid Incident — — May 31, 2025
Incident Information
| Incident Date | May 31, 2025 |
| Operator | MARATHON PIPE LINE LLC |
| Commodity | REFINED AND/OR PETROLEUM PRODUCT (NON-HVL) WHICH IS A LIQUID |
| Pipeline Type | hazardous_liquid |
Location
| State | |
| Coordinates | 42.51633, -113.71058 |
Cause
| Cause | INCORRECT OPERATION |
| Subcause | "VALVE LEFT OR PLACED IN WRONG POSITION, BUT NOT RESULTING IN A TANK, VESSEL, OR SUMP/SEPARATOR OVERFLOW OR FACILITY OVERPRESSURE" |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | $500 |
| Emergency Response | $0 |
| Other Costs | $0 |
Location Map
Incident Narrative
"ON MAY 31ST, 2025, A THIRD PARTY NOTIFIED THE PIPELINE OPERATIONS CENTER OF A RELEASE AT BURLEY STATION AT 13:44. THE LINE WAS DOWN AND STATION WAS ISOLATED AT 13:59. RESPONDING PERSONNEL DISCOVERED THERMAL RELIEFS ON THE PIG LAUNCHER AND RECEIVER WERE DISCHARGING TO ATMOSPHERE AND CONTAINMENT. AT THIS TIME THE ACCIDENT CAUSE IS STILL UNDER INVESTIGATION. SUPPLEMENTAL UPDATE: THE STATION PIG LAUNCHER AND RECEIVER, BOTH EQUIPPED WITH THERMAL PRESSURE RELIEF VALVES (TPRV) WITH RELIEF SETPOINTS OF 1,200 PSI, WERE EXPOSED TO THE SUSTAINED MAINLINE PRESSURE AND BEGAN RELIEVING. THE TPRVS WERE BOTH DESIGNED WITH TUBING ROUTED TO SECONDARY CONCRETE CONTAINMENT DRAINING TO THE SUMP. THE SUSTAINED HIGH PRESSURE AND TURBULENT FLOW THROUGH THE TPRVS CAUSED BOTH TUBES TO SHIFT OUT OF THE SECONDARY CONTAINMENT, THE LAUNCHER TPRV CAP CAME OFF, RELEASING TO THE ATMOSPHERE, AND THE TUBING SEPARATED FROM THE RECEIVER TPRV, ALSO RELEASING TO THE ATMOSPHERE. INVESTIGATION REVEALED THAT THE DESIGN OF THE TRPV DISCHARGE TUBING WAS INTENDED TO HANDLE SMALLER, LOW-PRESSURE VOLUMES RATHER THAN SUSTAINED HIGH-PRESSURE FLOW. THE INVESTIGATION FOUND THAT THE MAINLINE PRESSURE RELIEF VALVE MAY HAVE BEEN RELIEVING AT A HIGHER PRESSURE DUE TO METAL GALLING-INDUCED DRIFT. MPL HAS REPLACED THE MAINLINE VALVE. THE INVESTIGATION REVEALED THAT OPERATIONS HAD A HISTORICAL PRACTICE OF LEAVING THE KICKER VALVE (IS016) OPEN ON THE LAUNCHER TO MANAGE THERMAL PRESSURE, AND THAT THE BYPASS VALVE ON THE RECEIVER (IS020) WAS ALLOWING PRESSURE TO PASS AND WAS SCHEDULED FOR REPLACEMENT. THESE CONDITIONS ALLOWED THE MAINLINE PRESSURE AND HIGHER VOLUME TO ENTER THE PIG LAUNCHER AND RECEIVER. THE ACCIDENT RESPONSE CONSISTS SOLELY OF LONG-TERM REMEDIATION AND/OR MONITORING, CONDUCTED UNDER THE AUSPICES OF AN AUTHORIZED GOVERNMENTAL AGENCY OR ENTITY. MPL ENTERED INTO A CONSENT AGREEMENT WITH THE STATE OF IDAHO. THE SITE ALSO HAS HISTORIC CONTAMINATION FROM A RELEASE PRIOR TO MPL OWNERSHIP. THE COSTS OF THE ONGOING REMEDIATION HAVE BEEN UPDATED."
About This Pipeline Incident
Pipeline incident data is reported to the Pipeline and Hazardous Materials Safety Administration (PHMSA). All significant incidents involving fatalities, injuries, or property damage over $50,000 must be reported.