SACRAMENTO — As fires burned across Northern California last fall, Pacific Gas and Electric Co. launched a lobbying campaign whose outcome could mean billion of dollars for the utility.

PG&E, joined by California’s other big utility companies, pushed Sacramento to change a system that holds them financially liable for any wildfires sparked by their equipment, whether or not they followed the state’s safety rules. They found a powerful ally in Gov. Jerry Brown, who argued that as wildfires increase in size and intensity, the current system risks destabilizing the companies that supply the state’s electricity.

The utilities’ 10-month lobbying push, however, appears to have failed. At least for now.

On Saturday, a key state senator working with the governor’s office said the proposed liability changes would not pass during the current session, which ends Aug. 31.

Slammed by opponents as a utility bailout, the proposed changes were too contentious and complex to settle in the session’s remaining days, said Sen. Bill Dodd, D-Napa, co-chairman of the legislative conference committee on wildfire preparedness and response. And the debate made it difficult for lawmakers to focus on other fire-related measures, such as how the state can better manage the millions of drought-killed trees that are fueling the fires. Dodd’s comments came days after Senate Republican leaders called for dropping the liability issue for now.

“It was a tough fight,” Dodd said of the liability changes. “So we are pivoting.”

The conference committee, he said, will release a plan next week on what lawmakers feel they can accomplish this month.

PG&E, which could face up to $17 billion in damages from the October wildfires, declined to comment Saturday, as did the governor’s office.

The utilities are unlikely to give up the fight. But they will have to pursue it without Brown and his renowned arm-twisting prowess, because the governor’s final term ends in January.

The issue of changing liability rules touched off a fierce lobbying campaign that intensified in recent weeks.

Homeowners suing PG&E, as well as North Bay city and county officials, argued against any changes to the system, even drawing public support from longtime PG&E foe Erin Brockovich, whose fight against the utility over groundwater contamination was depicted in a movie. The utilities, backed by labor unions and business groups, formed the BRITE Coalition, for Building Resilient Infrastructure for Tomorrow’s Economy, and blanketed the airwaves with ads that called the current liability system unfair.

Under a doctrine known as inverse condemnation, California utility companies can be held liable for economic damages from wildfires sparked by their equipment, even if they followed all of the state’s safety rules. As wildfires in the state grow more frequent and destructive, utility lobbyists have warned lawmakers that the companies could eventually be driven into bankruptcy if that system doesn’t change.

Fire investigators have blamed PG&E’s equipment for starting 16 of the wildfires that devastated Northern California last fall. In 11 of those cases, investigators with the California Department of Forestry and Fire Protection found evidence that the company violated state safety laws. The cause of the most destructive fire — the Tubbs Fire that tore through Santa Rosa — has yet to be released.

PG&E already took a $2.5 billion charge against earnings this year — a figure larger than the company’s profit for all of 2017 — to cover the minimum liability that the company expects to face from last fall’s fires. While Wall Street analysts say the company is not in danger of bankruptcy, PG&E executives have warned that its cost of obtaining insurance is skyrocketing — an expense that will eventually be passed on to customers.

The liability changes Brown had proposed would have required courts to take into account whether utilities acted prudently in maintaining their systems before holding them liable. He also wanted judges to weigh the damage caused by a fire against the public benefit of providing electricity.

Brown’s proposal would have applied only to fires that began after Jan. 1, purposely excluding October’s deadly Wine Country fires and the blazes that tore through Ventura and Santa Barbara counties in December. Critics called it both a bailout for the utilities and a potential violation of the state Constitution, because it could have deprived property owners of their right to compensation when a utility providing a public benefit took or damaged their property.

“Victims of last year’s fires and future victims can breathe a sigh of relief that their constitutional rights are protected,” said lobbyist Patrick McCallum with Up From the Ashes, a campaign — funded by lawyers suing PG&E — that had been fighting to block changes to the state’s liability laws.

He said, however, that negotiations would continue on other fire-related reforms, including ways to make sure the utilities remain financially stable. Lawmakers have discussed possibly creating an insurance pool for the companies.

Melody Gutierrez and David R. Baker are San Francisco Chronicle staff writers. Email: mgutierrez@sfchronicle.com, dbaker@sfchronicle.com Twitter: @MelodyGutierrez, @DavidBakerSF