NTSB Faulted PG&E for Shoddy Work in 2008 Blast in Rancho Cordova, California

(Sept. 10) -- Shoddy repair work and a nearly three-hour delay in getting experienced workers to the scene caused a fatal 2008 residential explosion in a neighborhood served by giant utility Pacific Gas & Electric, according to a federal report released earlier this year.

Justin Sullivan, AP

PG&E admitted in December that the deadly 2008 Rancho Cordova, Calif., explosion had resulted from a bad repair job.

National Transportation Safety Board inspectors cited the use of a faulty pipe and a two-hour, 47-minute delay in getting qualified employees to the area as causes of a natural gas explosion that killed one and injured five on Christmas Eve in 2008 in Rancho Cordova, Calif., near Sacramento. A full copy of the report is on the NTSB's website.

On Friday, federal officials announced that NTSB inspectors were en route to San Bruno, Calif., about 80 miles west of Rancho Cordova, to investigate a massive natural gas explosion that killed at least four, destroyed dozens of homes and prompted a state declaration of emergency.

Bay Area neighbors said they had smelled "heavy gas" for weeks. PG&E spokesman Blair Jones, interviewed via phone by CNN's Kyra Phillips on Friday, would not confirm neighbors' reports or whether utility inspectors had recently been in the area. The company serves 15 million customers in Northern California.

In December 2009, PG&E admitted that the 2008 Rancho Cordova explosion had resulted from a bad repair job. PG&E has made a number of changes to its operations since the explosion, the Sacramento Bee quoted company spokesman Brian Swanson as saying. Technicians were retrained and given gas-detection devices, he said. Evacuation policies were also changed.

California Lt. Gov. Abel Maldonado told reporters Friday that the ground-shaking blast in San Bruno was caused by a pipe rupture. "We don't know why," he said. "We want to know what happened. How long did it take to shut off the gas in that pipe?"