Investigators say that a 2017 wildfire that killed 22 people in Northern California wine country was caused by a private electrical system, not equipment belonging to embattled Pacific Gas & Electric Corp.
The state firefighting agency concluded that the blaze started next to a residence. It did not find any violations of state law.
"I eliminated all other causes for the Tubbs Fire, with the exception of an electrical caused fire originating from an unknown event affecting privately owned conductor or equipment," California Fire Battalion chief John Martinez wrote.
Some details about the property, including its owner and address, were blacked out of the report. It said the Napa County property was built in 1946 on about 4.2 hectares with a wine cellar, pool and several outbuildings.
The fire was one of more than 170 that torched the state in October 2017. It destroyed more than 5600 structures over more than 148sq km in Sonoma and Napa counties.
Pacific Gas & Electric Corp previously said it planned to file for bankruptcy protection next week, citing billions of dollars in potential damages from lawsuits linking its equipment to other deadly blazes for which it had been determined to be at fault.
The company said in a statement that despite the finding, Pacific Gas & Electric Corp "still faces extensive litigation, significant potential liabilities and a deteriorating financial situation."
A state senator said that just because a private electric line caused the wine country fire does not let the utility off the hook for the role of its equipment in other devastating fires in the state.
State Senator Bill Dodd, a Napa Democrat, said the finding doesn't negate systemwide issues plaguing California's largest utility.
Lawmakers are under pressure to find a solution that addresses utility reform and compensates wildfire victims.
"This underscores the idea that we all have a role to play in wildfire prevention," said Mr Dodd a frequent critic of Pacific Gas & Electric Corp, who noted that the company has already been found at fault for more than a dozen other Northern California wildfires.
Pacific Gas & Electric Corp said in a 2 January court filing that it believed a handyman performing unlicensed electrical work started the wine country fire.
In the report released Thursday by the state, one witness reported seeing a transformer explode. Another reported seeing the fire approach a Pacific Gas & Electric Corp power pole.
One witness, Charlie Brown Jr of Calistoga, said the electrical wiring leading from the property where investigators concluded the fire started had not been used in years.