(Bloomberg) -- A PG&E Corp. worker who spotted the initial flames of the second-largest wildfire in California history faces questioning by a federal judge who’s investigating the utility’s role in sparking the blaze. 

U.S. District Judge William Alsup, who oversees PG&E’s criminal probation, told the company that for a hearing Monday in San Francisco it must bring the line worker known as a troubleman who first discovered that a tree had fallen onto a power line in a mountain canyon north of Sacramento, where the Dixie Fire erupted.

Alsup has asked why it took PG&E almost 10 hours to respond to the first report of an outage on the line in the early morning of July 13. PG&E has said in court filings that workers initially didn’t see indications of a fire and the troubleman sent to investigate had difficulty accessing the location because of the remote terrain and a bridge closure. 

The stakes are mounting for PG&E if it’s found at fault for the Dixie Fire and others that have ravaged Northern California in recent years. The company is fighting criminal charges for a 2019 fire and facing a criminal probe for a 2020 blaze. Alsup’s scrutiny could put additional pressure on state regulators to escalate their oversight of the company. Meanwhile, if PG&E is found to have willfully disregarded public safety, it may be denied protection in a California wildfire insurance fund. 

Read More: PG&E Pressed by Judge on Handling of Raging California Fire

Since its ignition, the Dixie Fire has consumed more than 950,000 acres while burning most of the Gold Rush-era town of Greenville. It was the first blaze in state history to burn from one side of the Sierra Nevada mountain range to the other. The wildfire has destroyed 1,329 structures and resulted in one death, according to the California Department of Forestry and Fire Protection. The cause of the fire remains under investigation.

Alsup has been scrutinizing PG&E’s role in sparking wildfires as part of his oversight of the company that stems from a 2010 deadly natural gas explosion. PG&E emerged from bankruptcy last year after its equipment was blamed for starting some of the worst blazes in California history, including the 2018 Camp Fire that destroyed the town of Paradise and killed 85 people. 

For Monday’s hearing, Alsup has requested the appearance of two PG&E employees who provided information about a drone that firefighters reportedly said interfered with initial efforts to put out the Dixie Fire. PG&E has said that neither the company nor contractors working on its behalf were operating a drone near where the fire started.

The case is U.S. v. PG&E, 14-cr-00175, U.S. District Court, Northern District of California (San Francisco).

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