SAN FRANCISCO (CN) — After grilling a Pacific Gas & Electric worker on the witness stand Monday, a federal judge laid out a theory on how the Dixie Fire started and ordered the utility to explain why it failed to cut power to a high-voltage line suspected of igniting the blaze.
“Why was the power left on in that circuit,” U.S. District Judge William Alsup asked during a hearing on PG&E’s criminal probation Monday. “That’s a key question that you’ve got to answer.”
An unnamed PG&E worker testified in court that he saw two blown fuses and flames burning at the base of a tree leaning on a 12-kilovolt power line as he responded to a reported outage in Plumas County on July 13.
Noting that the outage was detected about 10 hours before the fire is believed to have started, Alsup theorized that a fallen tree transmitted electric current from the line to the ground, eventually sparking a blaze that has become the second largest wildfire in California history. That explanation would be consistent with a PG&E worker’s testimony that he saw flames on the ground near the base of the tree but no fire on the tree itself.
Alsup said it was a “very plausible scenario” that the fallen tree caused what PG&E refers to in its state-mandated wildfire safety plan as a “ground fault,” a situation where a tree acts as a conductor carrying electricity from a line to the ground.
“The power went through the wood and the moisture of that tree and eventually caught it on fire,” Alsup said.
The worker reported seeing at least one of three fuses blown on a far-away power pole from his binoculars when he arrived at the Cresta Dam in Feather River Canyon that day. He couldn't get to the power pole until about four hours later because a temporary bridge closure blocked his path.
Alsup asked the PG&E worker why he didn't drive a few minutes to a nearby switch, called Switch 941, and shut the power down after he spotted at least one blown fuse.
“When you were down there at the dam looking with your binoculars, wouldn’t it have been better to go switch off 941 before you went out there?” Alsup asked. “If there was a ground fault at the time, the tree could ignite in the time that you were driving up there.”
The worker replied that he saw no indications of fire or a tree on the line when he spotted the blown fuse. He added it’s not PG&E’s policy to cut power to customers without a reason and noted a nearby railroad signal and track switches rely on that electricity.
He also told Alsup that PG&E taught him about wildfire risks associated with power lines, but that he did not receive specific training on “ground faults.”
The worker also recanted a statement he made to an emergency dispatcher on July 13 when he said, “there’s a tree on the line that started the fire.” The worker emphasized that he is not a fire investigator and can’t say what caused the blaze. The fire could have been caused by lightning, the worker said before acknowledging that it was a clear day with no recent reports of lightning in the area.
“Have you received any information from any other sources as to what the source of that fire might be other than a tree on the line,” Alsup asked.
“I have not,” the worker replied.
The judge demanded PG&E provide the names of dispatchers and other workers who may been involved in the decision not to cut power to the line that day.
“They ought to be brought in to explain why that decision was made to let that line stay energized in a high fire threat district,” Alsup said.
The judge also scolded PG&E for declaring in a prior written statement that the area where the Dixie Fire started was ranked 1,650 out of 3,205 for zones with the greatest equipment-related fire risk based on old criteria no longer in use.
“Elsewhere we have learned this rated 11th most dangerous out of 3,300,” Alsup said. “I thought that was misleading.”
The judge further asked PG&E to confirm if a railroad would have been affected had it cut power from a nearby switch before the fire started. He also demanded the company explain if its sensors were set up to detect a ground fault like the one he suggested may have caused the fire.
He ordered PG&E to submit written responses by Friday.
Before concluding the hearing, Alsup noted that PG&E’s five-year criminal probation will expire in January 2022, but he intends to keep holding the company accountable until that time comes. PG&E is on probation for felony convictions related to the 2010 San Bruno gas pipeline explosion.
“In January, I’ll be out of the case. Probation will end,” Alsup said. “But until then I’m going to do my job. Your company is a convicted felon that poses a safety hazard to the people of California, and my job is to try to rehabilitate you the best I can in the five years I have jurisdiction. I plan to do it right up until the last minute.”
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