NTSB to decide cause of gas pipeline explosion

By JOAN LOWY | August 30, 2011 | 3:15 AM EDT

National Transportation Safety Board Chair Deborah Hersman stands next to the damaged pipe from the San Bruno natural gas explosion during a news conference at the NTSB Training Center and Lab in Ashburn, Va., Monday, Aug. 29, 2011, to discuss the federal investigation into the San Bruno blast. The NTSB is expected to reveal the results of a yearlong investigation into the pipeline explosion (AP Photo/Manuel Balce Ceneta)

WASHINGTON (AP) — A federal safety panel plans to reveal the results of a yearlong investigation into a natural gas pipeline explosion near San Francisco that killed eight people.

The accident last September incinerated a suburban neighborhood and prompted a national reevaluation of pipeline safety.

Investigators for the National Transportation Safety Board will lay out their analysis Tuesday of what caused the rupture of a large Pacific Gas & Electric Co. transmission line buried beneath the community of San Bruno, Calif.

The explosion sent a giant pillar of fire into the air that continued to burn like a massive blowtorch for an hour and a half before PG&E employees were able to shut off the flow of gas.

It was the worst pipeline accident in a decade.