MARATHON PIPE LINE LLC

hazardous_liquid Incident —

Incident Information

Report Date
OperatorMARATHON PIPE LINE LLC
Commodity—
Pipeline Typehazardous_liquid

Location

State
Coordinates29.85781, -94.89817

Cause

CauseEQUIPMENT FAILURE
Subcause—

Casualties

Fatalities0
Injuries0

Costs

Property Damage
Lost Commodity
Public/Private Damage
Emergency Response
Environmental Remediation
Other Costs

Location Map

Incident Narrative

ON 9/27/2020, A PUBLIC NOTIFICATION WAS RECEIVED INTO THE CONTROL ROOM AT 13:50, STATING A SMELL OF ODOR AND OBSERVED VAPORS COMING FROM MOUNT BELVIEU JUNCTION. THE SYSTEM WAS SHUT DOWN AND FIELD PERSONNEL WERE NOTIFIED. UPON ARRIVAL, FIELD PERSONNEL REPORTED A VAPOR CLOUD AND FROST BALL AROUND VALVE BV1. REPORTING CRITERIA WAS DETERMINED TO BE MET AT 17:50 WHEN ESTIMATED COSTS WERE TO EXCEED $50,000 AND COMMODITY LOST TO EXCEED 5 GALLONS. ALL PRODUCT WAS CONTAINED ON-SITE AND HAS BEEN CLEANED UP. RELEASE VOLUME IS ESTIMATED TO BE 75 BARRELS CAUSED BY EQUIPMENT FAILURE OF THE VALVE PACKING. THE VALVE HAS BEEN REPLACED AND THE SYSTEM RETURNED TO NORMAL OPERATIONS. BASED UPON MANUFACTURER INSPECTION AND TESTING OF THE VALVE, THE CAUSE OF FAILURE WAS A BROKEN SEGMENT STOP, WHICH IS THE INTERNAL MECHANICAL LIMIT OF THE VALVE. THIS STOP PREVENTS THE STEM THREADS FROM CONTACTING THE VALVE PACKING AREA, AND THE VALVE GATE FROM IMPACTING THE INNER BOTTOM OF THE VALVE CASTING. THIS SEGMENT STOP FAILURE ALLOWED THE VALVE GATE TO OVERTRAVEL, RESULTING IN THE STEM THREAD CONTACT WITH VALVE PACKING AND CREATING A PATH FOR RELEASE OF ISOBUTANE.

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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