PHOENIX — A 2025 law shielding Tucson Electric Power, Arizona Public Service and other electric utilities from most lawsuits if their equipment sparks a catastrophic wildfire had just one requirement: The power companies must create comprehensive plans to minimize the risk of fires.

But insurers and trial lawyers who initially argued against the law and negotiated changes to remove their opposition are rebelling now that the plans are being rolled out. They call them sparse, lacking detail and an exercise in “check the box” bureaucracy that will do little to boost protection while leaving homeowners and other Arizonans on the hook if they lose everything in a fire.

In exchange, the utilities will be shielded from lawsuits that could cost them billions of dollars if a town like Payson or Prescott is wiped out by a wildfire caused by their power lines.