PG&E says its equipment probably caused a major fire, but taxpayers could be on the hook.

Pacific Gas & Electric Co. said its equipment likely caused the devastating Camp Fire, according to a financial disclosure filed Thursday. But taxpayers could still come out on the losing end.

The company claimed a $10.5 billion write-down due to the 2018 fire, as well as $1 billion related to 2017 fires. This likely improves PG&E's contention it needs bankruptcy protection. It also gives a graphic illustration of the need for the utility to spend billions of dollars on maintenance work to prevent the next fire.

Company spokespeople have repeatedly said the cause of the fire "has not yet been determined." But PG&E added the key sentence in the Securities & Exchange Commission disclosure issued at the same time it announced earnings for the last quarter of 2018.

"Although the cause of the 2018 Camp Fire is still under investigation, based on the information currently known to the company and reported to the California Public Utilities Commission (CPUC) and other agencies, the company believes it is probable that its equipment will be determined to be an ignition point of the 2018 Camp Fire," the company said.

"PG&E can tell the press basically anything they want to," said Michael Danko, a partner with Danko Meredith APC in Redwood City who represents about 200 victims of the 2017 Tubbs Fire and other blazes. "They can put in court filings a lot of gobbledygook with more or less impunity. But when you lie to the SEC, there's potentially serious criminal repercussions."

The filing also provides more specifics about how the fire may have begun in the early morning hours of Nov. 8, including "a broken C-hook" and "a flash mark" on the tower. Danko also pointed to media reports from Wednesday saying the company deferred maintenance on the location for years.

"It's really a message that I'm trying to get out to the overwhelming number of survivors who have not made a claim that they ought to, because PG&E is saying they're responsible and they're preserving $10 billion to pay off the claims," Danko said.

While overseeing its criminal probation from the 2010 San Bruno gas line explosion, U.S. District Judge William H. Alsup has repeatedly grilled PG&E on its wildfire mitigation plans. Attorneys watching that case say Alsup has broad powers to order the company to take action. U.S. v. Pacific Gas & Electric Co., 14-CR175 (N.D. Cal., filed April 1, 2014).

"It is a real conundrum how to approach this situation," said Shelley Ross Saxer, a Pepperdine University School of Law professor who specializes in land use issues. "Somebody is going to have to pay."

Saxer said the California Public Utilities Commission would likely bar PG&E from passing the costs on to ratepayers, especially if it is found negligent. Any effort by the Legislature to have taxpayers shoulder the cost would likely be very unpopular.

But the "huge capital investment" necessary to bury power lines and do other maintenance and improvements doesn't go away, Saxer added. Meanwhile, she noted, PG&E's stock price dropped again on Thursday's news, though by less than 5 percent.

Saxer is working on a law review article tentatively titled, "Paying for Disasters." It examines questions such as whether California should change its inverse condemnation law, which makes utilities liable for damages caused by their equipment even if they were not negligent, under a takings theory similar to eminent domain.

She also is evaluating the web of lawsuits that can radiate out from major fires. For instance, Southern California Edison is facing nearly 80 lawsuits over deadly mudslides that followed a blaze caused by its equipment. Edison then sued Santa Barbara County and other public entities claiming they made the mudslides worse by failing to maintain debris basins.

The state is already facing significant fire costs. Even before the Camp and Woolsey fires, the California Department of Forestry & Fire Protection had already nearly exhausted its 2018-19 budget less than three months into the current fiscal year.

Gov. Gavin Newsom has proposed adding $40 million to the state's firefighting budget, but some lawmakers are pushing to more than double this amount. On Feb. 13, Newsom signed AB 72, an emergency budget bill that $31.3 million to backfill lost property taxes in seven fire-ravaged counties.