As Californians vote by mail and prepare to cast ballots in person during the state’s March 3 Democratic presidential primary, Sen. Bernie Sanders is sharpening his criticism of an often-controversial business: Pacific Gas and Electric Co.

The Sanders campaign is distributing a nearly 3-minute video assailing PG&E for its role in recent wildfires. In the digital advertisement, several activists, a survivor of the 2018 Camp Fire and others lambaste the San Francisco energy company.

Speakers describe PG&E as being “caught in a death spiral” and blame it for “decades of negligence.” Sanders is seen walking through the burned remains of Paradise (Butte County) toward the end of the video as his supporters champion the Vermont senator’s proposed Green New Deal — and indicate they want the investor-owned PG&E to become a publicly owned utility.

Sanders’ campaign is running the ad on YouTube and promoting it on Facebook and Instagram.

The video’s debut suggests that Sanders, who has led several recent California primary polls, sees an opportunity in PG&E’s woes. Economic justice and the fight against climate change are pillars of his campaign, and he has long railed against corporate wrongdoing. In California, PG&E’s responsibility for deadly fires has led to ongoing legal and political repercussions, including from Gov. Gavin Newsom, who has repeatedly threatened a state takeover of the company.

Sanders visited Paradise in August and pointed to the destruction brought by the Camp Fire — which was caused by a PG&E power line — as he touted his aggressive climate proposals. Paradise should be “the wake-up call for our entire nation” about the realities of climate change, Sanders said at the time.

He also had sharp words for PG&E in October, when the company shut off electricity for millions of people to prevent its power lines from starting more catastrophic fires.

“The people of California are suffering because of the greed and corruption of utility corporations and their executives,” Sanders said in a statement at the time. After Newsom said a state takeover was possible in November, Sanders applauded the governor in another statement that said California residents “cannot remain hostage to a profiteering corporation for a very basic human need.”

In response to the new campaign video, PG&E spokesman James Noonan said in an email that the company is focused on public safety and is working to get fire victims “paid fairly and expeditiously” through its bankruptcy case.

PG&E is “committed to doing right by the communities impacted by wildfires, and to doing everything we can to reduce the risk of wildfires in the future,” Noonan said in the email. The company’s workforce of more than 20,000 people has “made tremendous progress” to improve fire safety in recent years, “and there is much more work for us to do ahead,” he said.

“Fighting climate change is bigger than politics. It requires a collective approach with all of us working together to limit and adapt to its impacts, in a way that leaves no one behind,” Noonan said. “PG&E recognizes the foundational role clean energy has in enabling this transition, and is making significant progress in doing our part with more than 85% of our delivered energy coming from non-emitting resources today.”

PG&E officials “stand ready” to help the state and country accomplish their “bold clean energy goals,” while delivering power that is “safe, reliable, clean and affordable,” he said.

The ad could help Sanders expand his support base in California, said David McCuan, a political scientist at Sonoma State University.

“Everyone can identify with PG&E and the fires,” McCuan said. “It’s not just activists that want to take over PG&E.”

It’s a smart move for Sanders, McCuan said — and something that other candidates seeking the Democratic nomination may follow. Criticizing PG&E over its connection to devastating Northern California fires echoes long-standing critiques of other “big, bad boogeymen” such as “Big Oil, Big Tobacco, Big Pharma,” McCuan said.

Sanders is also tapping into widespread negative perceptions about PG&E following recent fires and mass blackouts. A Change Research survey of 2,605 likely general election voters published in October found that 61% of those who responded had unfavorable views of PG&E — up from 49% eight months earlier. The survey had a margin of error of 1.9 percentage points.

“He is preaching to the choir, and at the same time asking those that are not of the converted to give a closer look at his policies,” McCuan said.

Sanders’ ad comes as California voters, a majority of whom are registered to vote by mail, are already beginning to cast their ballots.

The campaign video shows familiar scenes of the Golden Gate Bridge and PG&E’s headquarters in downtown San Francisco, along with shots of protesters calling for a government takeover of the company and devastation from wildfires. The video at one point shows the Santa Rosa site of the Journey’s End mobile home park, which was devastated by the 2017 Tubbs Fire.

Activist Emily Algire says in the Sanders video that PG&E “has a long, long history of really messing up the people that they are supposed to be taking care of.” Clinical psychologist Fereshteh Madjlessi says her only “sliver of optimism” and “faith, at this point,” is Sanders.

The video concludes with a suggestion that the investor-owned utility should be run by the government.

Sanders has already come out in support of that idea, which PG&E has consistently resisted. His campaign website includes a survey that encourages respondents to “add your name to support bringing PG&E under public ownership.”

J.D. Morris is a San Francisco Chronicle staff writer. Email: jd.morris@sfchronicle.com Twitter: @thejdmorris