Jan. 24 (UPI) -- California fire officials said Thursday that a private electrical system was responsible for starting a 2017 fire that was the second most destructive blaze in the state's history.
The Tubbs Fire, which began Oct. 8, 2017, was caused by a private electrical system adjacent to a residential structure, Cal Fire said after conducting an "extensive and through" investigation into the incident.
The state fire authority also stated it did not identify any violations of state law or Public Resources Code related to the fire.
Cal Fire reported that 22 people were killed, one firefighter was injured and 5,636 structures were destroyed in the blaze.
The owner of the 10.5-acre property said in 2017 that her house in Calistoga was unoccupied at the time of the fire, but she believed strong winds knocking trees into wires ultimately sparked the blaze, SFGate reported.
The blaze was part of a "fire siege" that took place in the state in October 2017, during which more than 170 fires burned at least 245,000 acres in Northern California.
Approximately 11,000 firefighters from 17 states and Australia helped combat the wildfires.
Shares of Pacific Gas and Electric spiked Thursday after the news clearing it of responsibility in the Tubbs Fire.
The stock shot up 74.59 percent after the news, but later dropped 5.38 percent in after-hours trading.
PG&E announced plans to file for Chapter 11 bankruptcy protection on Jan. 14.
The utility was blamed for 17 wildfires including the Camp Fire, which killed 86 people, becoming the deadliest wildfire in California history. The company initially faced blame for the Tubbs Fire as well.