A dozen of the wind-driven blazes that swept northern California's wine country last fall, killing 46 people in the deadliest firestorm in state history, were sparked by PG&E-owned power lines, state officials said their investigation concluded on Friday.
The California Department of Forestry and Fire Protection, or CalFire, also said its investigators had found "evidence of alleged violations of state law" by Pacific Gas & Electric Company and referred those cases to county prosecutors for further review.
PG&E issued a statement in response saying the company looked forward to reviewing the CalFire reports, adding, "We continue to believe our overall programs met our state's high standards."
The findings could have tremendous implications for the San Francisco-based utility company in terms of potential legal liability for one of California's most lethal and costly disasters.
CalFire's investigation covered 12 individual blazes accounting for much of the conflagrations that erupted the night of Oct. 8 and raced across several counties north of San Francisco, collectively dubbed the North Bay Fires, or the October 2017 Fire Siege.
The firestorm claimed 46 lives, scorched at least 245,000 acres (99,148 hectares), and incinerated 8,900 homes and other structures, including entire subdivisions in the Sonoma County town of Santa Rosa. An estimated 100,000 people were placed under evacuation orders and the region's renowned wine-making region was thrown into turmoil.
Causes cited by CalFire included downed power lines, fallen utility poles and trees blown into electrical wires — all equipment owned by PG&E — during the course of fierce winds that roared through the region to spread the resulting flames with unprecedented speed.
A CalFire spokesman, Michael Mohler, said agency officials looked for specific lapses ranging from maintenance and equipment failures to improper vegetation clearance, but declined to discuss specific findings because the matter remains under investigation.