PG&E ordered to preserve evidence

California utility regulators have told Pacific Gas and Electric Co. to preserve any evidence that could be connected to this week’s deadly wildfires in the North Bay, including all broken power poles and electrical conductors.

State fire officials are investigating whether power poles and electrical lines knocked down by a severe windstorm Sunday night played a role in sparking the fires, which have killed at least 31 people and displaced thousands.

On Thursday, the California Public Utilities Commission sent PG&E a note reminding the utility to preserve all evidence related to potential causes of the fires. That includes not just physical equipment such as damaged poles but also emails and documents related to PG&E’s tree-trimming program in the area.

The letter, from the director of the commission’s safety division, notes that commission staff first verbally notified PG&E’s senior director of regulatory affairs on Tuesday evening to preserve evidence related to the fires. According to the letter, “PG&E acknowledged that it would do so.”

A PG&E spokesman said Thursday that the company had received the CPUC’s letter and would support “the re- views by any relevant regulator or agency.”

The utility, California’s largest, has acknowledged that Sunday’s windstorm knocked trees and tree limbs into power lines and poles across the North Bay. But PG&E has insisted that blaming the fires on that equipment remains premature. Officials with the California Department of Forestry and Fire Protection, known as Cal Fire, say they are examining the utility’s electrical equipment as one of several potential causes of the fires.

“Since the wildfire began Sunday night, in the cases where we have found instances of wires down, broken poles and impacted infrastructure, we have reported those to the Commission and continued to share that information with Cal Fire,” said PG&E spokesman Keith Stephens, in a statement. “We understand that there will likely be reviews of these wildfires by the appropriate agencies, but right now we are focused on life safety and service restoration.”

Over the course of the week, the windstorm and fires have cut off power to 255,218 PG&E customers, according to the company. By Thursday afternoon, electricity had been restored to 80 percent of those customers. Most of those still blacked out are in Santa Rosa.

The letter from the utilities commission instructs PG&E to tag and catalog all physical evidence so the commission’s safety division staff can reconstruct the poles for analysis. The company must also notify the commission in advance before moving physical evidence from the field to a storage facility.

David R. Baker is a San Francisco Chronicle staff writer. Email: dbaker@sfchronicle.com Twitter: @DavidBakerSF