NORTHERN NATURAL GAS CO
gas_transmission Incident —
Incident Information
| Report Date | — |
| Operator | NORTHERN NATURAL GAS CO |
| Commodity | — |
| Pipeline Type | gas_transmission |
Location
| State | |
| Coordinates | 43.84277, -92.93027 |
Cause
| Cause | EQUIPMENT FAILURE |
| Subcause | — |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | — |
| Lost Commodity | — |
| Public/Private Damage | — |
| Emergency Response | — |
| Environmental Remediation | — |
| Other Costs | — |
Location Map
Incident Narrative
MARCH 30, 2024, AT 0702 HOURS, PASSERBY NOTIFIED THE EMERGENCY CALL CENTER OF VENTING GAS AT THE LA CROSSE REGULATOR STATION. GAS CONTROL WAS ABLE TO CONFIRM A CHANGE IN PRESSURE, AND FIELD OPERATIONS ARRIVED AT 0730 AND CONFIRMED THE RELIEF VENTING. AFTER CONFIRMING DELIVERY REQUIREMENTS, THE RELIEF VALVE WAS ISOLATED AT 0810. THE RELIEF VALVE AND PILOT WERE REPAIRED ON SITE AND RETURNED TO SERVICE MARCH 30, 2024, AT 1735 HOURS. THE POST INVESTIGATION DETERMINED THAT THE MODULATING PILOT SET POINT WAS SET TOO CLOSE TO THE NORMAL OPERATING PRESSURE. THE COOLING EFFECT OF REDUCING PRESSURE THROUGH THE MODULATING PILOT CAUSED MOISTURE TO FORM AND POTENTIALLY FREEZE THE PILOT. SINCE THE INCIDENT, IT WAS DECIDED TO REPLACE THE LA CROSSE RELIEF WITH A HIGHER SETTING PRESET BY THE MANUFACTURER/VENDOR TO AVOID FUTURE OCCURRENCES. THE MEASUREMENT TEAM IS IDENTIFYING LOCATIONS WITH SIMILAR OPERATING CONDITIONS, AND THEY WILL TEST AND ADJUST RELIEF SET POINTS OR REPLACE EQUIPMENT WHERE APPLICABLE.
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.