A natural gas pipeline operated by PG&E exploded Sept. 9, 2010, in San Bruno, Calif., killing eight people and damaging 38 homes.
The San Francisco Chronicle reported in April that PG&E indicated in an internal memo that a weld seam failed and likely caused a leak in 1988 about 9 miles south of the San Bruno accident.
The National Transportation Safety Board said PG&E didn't know what kind of pipe was beneath San Bruno and had said defective welds contributed to the explosion.
PG&E filed a motion in a state superior court stating it didn't have "actual knowledge" the pipeline posed a threat to public safety, the San Jose Mercury News reports. The report adds that it's unclear which company manufactured the faulty pipeline.
The company could face as much as $200 million in penalties related to the incident.
Attorneys for the survivors of the explosion said PG&E cut short its maintenance budget in the years leading up to the incident.