NORTHWEST PIPELINE CORP (WGP) — Gas transmission and gathering — incident on 2011-05-24

Gas transmission and gathering incident in LAVA, CARIBOU County, ID. Reported cause: MATERIAL FAILURE OF PIPE OR WELD. Reported consequences: 0 fatalities, 0 injuries, 1920 NATURAL GAS released, $68,500 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: 20110184.

Operator ID: 13845.

Reported incident date: 5/24/2011 12:30.

Location detail: M.P. 554.6

Cause detail: DESIGN-, CONSTRUCTION-, INSTALLATION-, OR FABRICATION-RELATED

Cause detail: DURING THE ANNUAL POCATELLO AIR PATROL OF THE PIPELINE, A LOCATION WITH DEAD VEGETATION WAS IDENTIFIED AT MILE POST 554.6. A GROUND PATROL WAS SENT TO INVESTIGATE AND FOUND THE DEAD VEGETATION AND USED A FLAME PACK TO IDENTIFY LEAKING GAS. BY PROBING AND SNIFFING, IT WAS DETERMINED THAT THE LEAK WAS ON THE 24" 1401 LOOP LINE. THE PIPELINE WAS IMMEDIATELY BLOWN DOWN TO 43 PSIG FROM MLV 8L-2. EXCAVATION MACHINERY WAS BROUGHT ON SITE AND BEGAN EXCAVATION. THE PIPE WAS FOUND SITTING ON A ROCK AND GAS WAS ESCAPING FROM THAT LOCATION. THE BLOW DOWN CONTINUED TO A SLIGHT POSITIVE PRESSURE. A TEMPORY PATCH WAS PUT OVER THE HOLE FOR THE NIGHT. THE FOLLOWING MORNING THE PIPE WAS CUT AND A 7.81 FT PUP WAS INSTALLED.

PHMSA trend classification: significant incident, not serious.

PHMSA standardized cause: MATERIAL FAILURE OF PIPE OR WELD — CONSTRUCTION, INSTALLATION OR FABRICATION-RELATED.

PHMSA indexed costs: $138,360 reported total cost, $85,753.952 in 1984 dollars, $150,661.34 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.