The report was released this week after Los Angeles County Superior Court Judge William Highberger said a delay caused by a California attorney general's office investigation no longer outweighed the public's right to know the cause of the fire.
"The Investigation Team (IT) determined electrical equipment associated with the Big Rock 16kV circuit, owned and operated by Southern California Edison (SCE), was the cause of the Woolsey Fire," the report stated. Under strong winds, a guy wire on a steel pole connected with an energized conductor, causing "heated material" to fall on vegetation "thereby causing the Woolsey Fire," it states.
A "communication line" that was hooked up to the steel pole also was energized and a second fire was reported about a quarter of a mile away underneath the communication line, the report states. The two fires merged to become the Woolsey fire, the report says.
However, five full pages and several sentences in the conclusory remarks remain redacted. The 70-page report includes the redacted pages under a section called "Violations."
The fast-moving Woolsey Fire burned 96,949 acres in Ventura and Los Angeles counties in November 2018, destroying 1,634 structures and causing three deaths.
"Absent additional evidence, SCE believes it is likely that its equipment was associated with the ignition of the Woolsey Fire," the company said.
The company said it did not find evidence of downed electrical wires at the suspected origin point of the fire, but it did report an outage on its electrical system near that point and found a pole support wire close to an electrical wire that was energized before that reported outage.
A witness reported seeing fire near the equipment around that time, the company said. The report also cited multiple witnesses who reported hearing a loud buzzing noise or experiencing a power outage before seeing smoke and fire in the area.
In a statement given to the Star on Wednesday, Edison spokesman Chris Abel said the company fully cooperated with investigators and "shared the conclusion of Ventura County Fire Department's redacted Woolsey report."
Abel did not respond to a CNN request for comment.
A Cal Fire spokesperson directed requests for comment to the Los Angeles Superior Court, which did not immediately respond.
Power line may have started current fire
The initial safety incident report describes overhead electrical facilities in the origin area of the Silverado Fire, but notes there was no activity on the circuit.
"We reported the incident despite seeing no activity on the nearby 12-kV circuit nor any downed power lines because it appears that a lashing wire attached to a telecommunications line may have contacted SCE's power line above it, possibly starting the fire," Abel told CNN earlier this week.
The fire began in a place considered to be a "high fire risk area," and will be investigated by the Orange County Fire Authority. The company promised to cooperate fully with that investigation.
"Our top priority is the safety of customers, employees and communities, which is why we continue to enhance our wildfire mitigation efforts through grid hardening, situational awareness and enhanced operational practices," Abel said.
The fire, one of the largest wildfires in Los Angeles County history, started on September 6 and charred at least 115,000 acres.
Edison spokesman David Song told CNN last month that the utility received a request from US Forest Service officials on September 15 to turn over a section of SCE's overhead conductor near Cogswell Dam. That's the area where the Bobcat Fire was sparked.