NORTHERN NATURAL GAS CO — Gas transmission and gathering — incident on 2016-04-26

Gas transmission and gathering incident in Not Within a Municipality, EAU CLAIRE County, WI. Reported cause: EXCAVATION DAMAGE. Reported consequences: 0 fatalities, 0 injuries, 6172 NATURAL GAS released, $80,000 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: 20160040.

Operator ID: 13750.

Reported incident date: 4/26/2016 15:35.

Location detail: 18.04

Cause detail: EXCAVATION DAMAGE BY THIRD PARTY

Cause detail: EXCAVATION ISSUE

Cause detail: IMPROPER BACKFILLING PRACTICES

Cause detail: ON APRIL 26, 2016, NORTHLAND EXCAVATION, A THIRD PARTY EXCAVATOR, STRUCK THE AUGUSTA BRANCH LINE (WIB19901) WITH A DEEP RIPPER ATTACHED TO A BULLDOZER. ALTHOUGH A ONE-CALL TICKET HAD BEEN MADE, IT WAS NOT SCHEDULED TO CLEAR UNTIL APRIL 28, 2016, AT 07:49. NORTHERN HAD PLANS TO LOCATE THE LINE ON APRIL 27, 2016. WISCONSIN HAS A 3-DAY WAIT PERIOD FOR ONE-CALL TICKETS. THE AUGUSTA #1 TBS HAS AN ALTERNATIVE FEED WITH VIKING GAS TRANSMISSION. WE ENERGIES SWITCHED OVER AND MAINTAINED SERVICE. NORTHERN STOPPLED THE AUGUSTA 3-INCH BRANCH LINE UPSTREAM OF THE FAILURE SITE AND REPAIRED THE DAMAGED SECTION OF THE LINE. THE DAMAGED SECTION WAS SENT TO A LABORATORY FOR ANALYSIS.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: EXCAVATION DAMAGE — THIRD PARTY EXCAVATION DAMAGE.

PHMSA indexed costs: $102,800 reported total cost, $57,839.84 in 1984 dollars, $126,927.954 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.