This Sunday, officials from Pacific Gas and Electric and the California Public Utilities Commission will hold a town hall in San Bruno about last September’s gas pipeline explosion. Federal investigators haven’t settled on a cause for the blast that killed eight people.
The National Transportation Safety Board is still investigating what set off the gas explosion and fire in San Bruno.
Democratic Congresswoman Jackie Speier represents the neighborhood where the blast happened. She says the metallurgical report has ruled out several possible causes. "It was not due to internal nor external corrosion," she says. "It wasn’t due to an excavation gouging, which is typically what happens in many of these situations, and it was not due to a pre-existing leak."
Speier says the investigation now shifts to other possible causes: metal fatigue in the pipeline, whether the welds were appropriate and human error.