NORTHERN NATURAL GAS CO

gas_transmission Incident —

Incident Information

Report Date
OperatorNORTHERN NATURAL GAS CO
Commodity—
Pipeline Typegas_transmission

Location

State
Coordinates37.59254, -99.41375

Cause

CauseMATERIAL FAILURE OF PIPE OR WELD
Subcause—

Casualties

Fatalities0
Injuries0

Costs

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

Location Map

Incident Narrative

ON NOVEMBER 7, 2023, A TECHNICIAN IDENTIFIED A GRADE 3 LEAK WHILE PERFORMING A LEAK SURVEY ON A CASED CROSSING. NO PPM WAS MEASURED IN THE ATMOSPHERE, BUT THE TECHNICIAN WAS ABLE TO DETECT 580 PPM WHEN THE CAP FOR THE VENT ON THE CASED CROSSING WAS REMOVED AND A PROBE WAS INSERTED IN THE VENT STACK. ON NOVEMBER 8, 2023, AN ETHANE DETECTOR WAS USED TO CONFIRM WHETHER THE PPM WAS NATURAL GAS OR NOT. ETHANE WAS CONFIRMED AND THE PPM HAD INCREASED TO 3,037 INSIDE THE VENT STACK AND 56 PPM AT ATMOSPHERE DUE TO AN INCREASE IN FLOW FROM THE PREVIOUS DAY. A PLAN TO ISOLATE THE SEGMENT WAS IMPLEMENTED WHILE THE ENGINEERING DEPARTMENT STARTED TO DEVELOP A REPAIR PLAN. ON NOVEMBER 9, 2023, THE ENGINEERING DEPARTMENT CONCLUDED THAT REPAIR COSTS WOULD EXCEED THE REPORTING THRESHOLD AND THE NRC WAS NOTIFIED AS SOON AS POSSIBLE AFTER THAT DETERMINATION. THE LEAK WAS STOPPED ON NOVEMBER 22, 2023, AFTER A LINE STOP WAS INSTALLED DOWNSTREAM OF THE LEAK, TO LIMIT THE AMOUNT OF GAS RELEASED TO THE ENVIRONMENT. THE CROSSING WILL BE REPLACED WITH A NEW HDD AND IS SCHEDULED TO BE COMPLETED MID-DECEMBER 2023. LAB REPORT INDICATES CRACKLIKE INDICATIONS ON THE ORIGINAL 1948 CONSTRUCTION SLEEVES AND WELDS.

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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