"DENBURY ONSHORE, LLC"

hazardous_liquid Incident — — October 16, 2025

Incident Information

Incident DateOctober 16, 2025
Operator"DENBURY ONSHORE, LLC"
CommodityCO2 (CARBON DIOXIDE)
Pipeline Typehazardous_liquid

Location

State
Coordinates31.28538, -90.50947

Cause

CauseEQUIPMENT FAILURE
SubcauseOTHER EQUIPMENT FAILURE

Casualties

Fatalities0
Injuries0

Costs

Property Damage$257,000
Emergency Response$190,000
Other Costs$0

Location Map

Incident Narrative

"A RELEASE OF CARBON DIOXIDE OCCURRED AT THE NEJD MLV-040 SITE ON OCTOBER 16, 2025. THE EVENT WAS FIRST IDENTIFIED WHEN TECHNICIANS PERFORMING MAINTENANCE ON THE MAINLINE VALVE AT MLV-040 OBSERVED CO2 LEAKING FROM THE VALVE STEM AREA AT APPROXIMATELY 6:50 PM CT. UPON NOTIFICATION TO THE CONTROL ROOM, UPSTREAM AND DOWNSTREAM REMOTE-OPERATED VALVES WERE CLOSED. ADDITIONAL BLOCK VALVES WERE MANUALLY CLOSED TO FURTHER ISOLATE THE SEGMENT. AIR MONITORING WAS INITIATED IN COORDINATION WITH LOCAL EMERGENCY RESPONDERS, AND NOTIFICATIONS WERE MADE TO THE APPROPRIATE AGENCIES. NO INJURIES, FIRES, OR EVACUATIONS OCCURRED, AND THERE WERE NO REPORTED IMPACTS ON NEARBY RESIDENTS. OPERATIONS PERSONNEL, IN COORDINATION WITH LOCAL EMERGENCY AGENCIES, ELECTED TO POSTPONE NIGHTTIME BLOWDOWN ACTIVITIES ON OCTOBER 16 TO ALLOW THE WORK TO PROCEED UNDER SAFER DAYTIME VISIBILITY AND IMPROVED MONITORING CONDITIONS. CONTROLLED DEPRESSURIZATION OF THE ISOLATED SEGMENT BEGAN THE MORNING OF OCTOBER 17, AND PROGRESSED IN STAGES AS NEEDED BASED ON BLOWDOWN RATES AND SITE CONDITIONS. AIR MOVERS AND CONTINUOUS MONITORING WERE UTILIZED TO SUPPORT PLUME CONTROL, AND ALL ACTIONS WERE CONDUCTED UNDER JOINT OVERSIGHT WITH EMERGENCY RESPONDERS TO ENSURE THE RELEASE WAS SAFELY MITIGATED. THE INVESTIGATION DETERMINED THAT THE STEM SEAL FAILED DUE TO GRADUAL AND TIME-DEPENDENT DEFORMATION OF MATERIAL (CREEP) ALLOWING FOR RELEASE OF CO2 FROM THE BALL VALVE. ADDITIONALLY, THE BALL SEATS WERE FOUND TO HAVE MATERIAL ENTRAINED LIKELY DUE TO WELDING DURING INITIAL CONSTRUCTION OF THE PIPELINE. THIS AFFECTED THE VALVE SEAT

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.

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