California utilities might have to pay billions of dollars in damage if state investigators find their power lines sparked last year’s devastating wildfires. And they’ll face similar bills in the future, whenever a tree falls across a power line and sparks a fire that reduces homes, hotels and schools to ashes. To head off financial disaster, the companies and the electrical workers’ union are frantically lobbying Golden State officials for relief from a system that the utilities say is unfair: They’re liable when their equipment ignites a fire, but they can’t automatically pass on the costs to consumers. “Our employers are now at financial risk, because the damage associated with these fires is literally billions and billions of dollars,” said Hunter Stern, a business representative for the International Brotherhood of Electrical Workers Local 1245, which represents 20,000 workers in California and Nevada. But advocates for ratepayers and wildfire victims say the current system works just fine, and that it gives utilities an incentive to trim nearby trees and invest in their infrastructure.