LOS ANGELES, March 13 (Xinhua) -- The 2017 devastating wildfire in western U.S. state of California, dubbed the Thomas Fire, was started by power lines coming into contact in high winds, said officials on Wednesday after a more than one-year probe.

The Thomas Fire, starting on Dec. 4, 2017, burned about 1,140 square km in total in Ventura and Santa Barbara counties and destroyed more than 1,000 structures in nearly 40 days.

Two lives were lost in the fire, including 32-year-old firefighter Cory Iverson. At one point, nearly 9,000 emergency personnel were working against the fire.

It became the largest wildfire ever recorded in California at the time, only to be exceeded months later by the Mendocino Complex Fire in 2018.

"A high wind event caused the power lines to come into contact with each other, creating an electrical arc. The electrical arc deposited hot, burning or molten material onto the ground, in a receptive fuel bed, causing the fire ... and the power line in question is owned by Southern California Edison (SCE)," said the Ventura County Fire Department in a statement.

The SCE, one of the largest electric utilities in the United States, issued a statement later Wednesday, questioning the investigation report.

"Notwithstanding today's report, a final determination on cause and responsibility will only be made through the legal process," said the SCE.

"With the increasingly serious, ever-growing wildfire threat to California, it is unmistakably clear that further urgent work is needed to develop thoughtful, comprehensive policies to address this statewide problem," explained the utility.

Some lawsuits have been filed by local residents against the SCE regarding the cause of the wildfires in Southern California, including the Thomas Fire.