NTSB issues prelim report on San Bruno gas line blast

SAN BRUNO — Federal officials have released a preliminary investigative report looking at last month's deadly California gas pipeline explosion.

The National Transportation Safety Board has not determined the cause of the blast. But its preliminary report confirms that a brief power failure shortly before the blast increased pressure in the segment of pipe that exploded.

Investigators say that after the power failure, pressure increased by 15 pounds-per-square-inch 11 minutes before the blast in a San Bruno neighborhood.

The Sept. 9 explosion killed eight people and destroyed 37 homes.

NTSB officials say a more detailed report will be released in coming months after scientific tests on the pipe segments.

Copyright 2010 The Associated Press.