NORTHERN NATURAL GAS CO — Gas transmission and gathering — incident on 2016-08-25

Gas transmission and gathering incident in Not Within a Municipality, LINCOLN County, KS. Reported cause: CORROSION FAILURE. Reported consequences: 0 fatalities, 0 injuries, 60 NATURAL GAS released, $50,000 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: 20160076.

Operator ID: 13750.

Reported incident date: 8/25/2016 13:20.

Location detail: 30.14

Cause detail: EXTERNAL CORROSION

Cause detail: ON AUGUST 25, 2016 AT APPROXIMATELY 1310 HOURS THE OPERATIONS COMMUNICATION CENTER RECEIVED A CALL FROM THE LINCOLN COUNTY, KANSAS DISPATCH OF BLOWING GAS IN LINCOLN COUNTY, KANSAS. SCADA READINGS INDICATED A RAPID DECREASE IN PRESSURE ON THE KSM20601-M640A BUSHTON TO TESCOTT A-LINE. FIELD OPERATIONS CONFIRMED THE PIPELINE HAD FAILED APPROXIMATELY 200-YARDS NORTH OF INTERSTATE HIGHWAY 70. THE HIGHWAY WAS BLOCKED OFF BY EMERGENCY RESPONDERS. AT APPROXIMATELY 1543-HOURS THE MAINLINE BLOCK VALVES WERE CLOSED UPSTREAM AND DOWNSTREAM OF THE SITE AND THE PRESSURE DECREASED TO 0-PSIG. PHMSA ACCIDENT INVESTIGATORS FROM THE CENTRAL REGION AND SOUTHWEST REGION ARRIVED ON SITE BY 20:30 AND AT 13:00 ON AUGUST 26, 2016, RESPECTIVELY. INITIAL EXAMINATION SHOWED THE PIPELINE RUPTURED DUE TO ISOLATED GENERAL EXTERNAL CORROSION. THE FAILED PIECE WAS 9-FEET LONG WITH ABOUT 18 SQUARE FEET OF THINNER WALL PIPE. THE SURROUNDING PIPE APPEARS TO BE IN GOOD CONDITION. THE FAILED PIECES WERE SENT FOR LABORATORY EXAMINATION. **UPDATE** NORTHERN HAS BEEN PROVIDING QUARTERLY UPDATES TO THE SOUTHWEST REGION PHMSA THAT CONTAINS MORE INFORMATION.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: CORROSION — EXTERNAL.

PHMSA indexed costs: $242,520 reported total cost, $217,374.106 in 1984 dollars, $311,138.406 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.