SAN FRANCISCO, Dec. 20 (UPI) -- Pacific Gas and Electric may have maneuvered around federal requirements on natural gas pipeline inspections prior to a deadly California blast, an audit found.
A natural gas pipeline owned by PG&E burst Sept. 9, sparking a massive fireball that ripped through a San Bruno, Calif., neighborhood. The explosion killed at least eight people and destroyed 37 homes.
A May audit obtained by the San Francisco Chronicle under the Freedom of Information Act found that PG&E used an inspection method dubbed "direct assessment" on its gas pipeline, including the San Bruno section.
Direct assessment involves running an electric current through the pipeline to test for weaknesses. The test, however, doesn't detect weak welds, which federal inspectors suggested could have led to the Sept. 9 blast.
Federal law requires PG&E to rule out weld failure before they run a direct assessment, though the utility found ways to get around the requirement, the Chronicle notes.
Furthermore, the Chronicle adds, PG&E said it wasn't aware that the San Bruno pipeline had the type of welds that officials are examining as a possible cause for the explosion.
More than 50 residents in a San Bruno neighborhood filed a lawsuit against PG&E for not taking "corrective and life-saving action" in response to complaints of alleged signs of a gas leak before the Sept. 9 explosion.
The U.S. National Transportation Safety Board in a preliminary report found an electrical failure at a PG&E facility caused a pressure surge in the pipeline just before the San Bruno explosion.