NORTHERN NATURAL GAS CO — Gas transmission and gathering — incident on 2021-07-22

Gas transmission and gathering incident in Not Within a Municipality, ELLSWORTH County, KS. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 197700 NATURAL GAS released, $100,000 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20210071.

Operator ID: 13750.

Reported incident date: 7/22/2021 13:19.

Location detail: 27.35

Cause detail: EXTERNAL CORROSION

Cause detail: ON JULY 22, 2021, AT 1:23 PM CDT THE ELLSWORTH COUNTY SHERIFFS OFFICE CONTACTED NORTHERN'S OPERATIONS COMMUNICATION CENTER TO REPORT A GAS LINE EXPLOSION NEAR 23RD ROAD AND AVENUE C OUTSIDE OF ELLSWORTH, KANSAS. THERE WAS FIRE BLOWING APPROXIMATELY 100 FEET IN THE AIR FROM THE M640E LINE AT MILEPOST 27.32. NO INJURIES WERE REPORTED AT THE SCENE. FIRE PERSONNEL WERE DISPATCHED TO THE SITE AT 23RD ROAD AND AVENUE C. THE SHERIFF CLOSED LOCAL ROADS SURROUNDING THE SITE. FIELD OPERATIONS PERSONNEL SHUT IN THE PIPELINE AT ISOLATION VALVES 640EBE01, LOCATED AT THE BUSHTON (KS) COMPRESSOR STATION AT MILEPOST 0, AND 640EBE0A, LOCATED AT THE TESCOTT (KS) COMPRESSOR STATION AT MILEPOST 46, AT 1:44 PM CDT. A MEMBER FROM THE FIELD TEAM ARRIVED AT 2:15 PM CDT TO CLOSE BLOCK VALVE 3 (640EBE03) AT MILEPOST 16.3. GRASS FIRES WERE BURNING IN THE AREA SURROUNDING THE INCIDENT SITE. ANOTHER TEAM MEMBER CLOSED BLOCK VALVE 5 (640EBE05) AT MILEPOST 34.8 AT 2:48 PM CDT, AND THE LINE FIRE WAS EXTINGUISHED. EMERGENCY SERVICES PUT OUT THE SURROUNDING GRASS FIRES. APPROXIMATELY 60 FEET OF PIPING WAS EJECTED FROM THE RUPTURE SITE IN FOUR SECTIONS. 11/30/21 UPDATE - CORRECTIONS PROVIDED BY PHMSAS ACCIDENT INVESTIGATION DIVISION: VOLUME OF GAS LOST CORRECTED TO 197,700; TIME VALVE 5 WAS ACTUALLY CLOSED CORRECTED TO 14:48; 'NOT WITHIN A MUNICIPALITY WAS CHECKED; PIR WAS CORRECTED AND NORTHERN IS USING 0.71 FOR HIGH BTU GAS; METALLURGICAL LAB COSTS WERE ENTERED AND THERE IS MORE COSTS TO COME; TOTAL COSTS UPDATED AUTOMATICALLY WHEN THE CORRECT NUMBERS WERE ENTERED; CAUSE IN PART G CHANGED TO METALLURGICAL ANALYSIS; AND TIME CHANGED TO 2:45 IN THE NARRATIVE FOR VALVE 5. THE METALLURGICAL ANALYSIS WAS WITNESSED BY PHMSA PERSONNEL AT STRESS ENGINEERING AND BRYAN LABS. 04/04/22 UPDATE: NO NEW INFORMATION. ACCIDENT INVESTIGATION DIVISION HAS METALLURGICAL REPORT. MARKED FINAL. 04/07/22 UPDATE: FOUND ERROR. AN EXTRA DECIMAL WAS INCLUDED IN 21C. ALL THE GAS WAS CONSUMED BY FIRE.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — EXTERNAL.

PHMSA indexed costs: $860,396 reported total cost, $487,732.31 in 1984 dollars, $803,877.994 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.