By Denny Walsh, Sacramento Bee

Federal prosecutors in Sacramento have collected $50.5 million from four companies found by investigators to be responsible for igniting two wildfires that burned more than 31,000 acres of national forest land, U.S. Attorney Benjamin Wagner announced Thursday.

The Power Fire, which ignited on Oct. 6, 2004, in the Eldorado National Forest in a remote area of Amador County, started when tree trimmers discarded cigarette butts on the floor of the forest, Wagner said.

The Whiskey Fire ignited on June 12, 2008, in the Mendocino National Forest, when Pacific Gas & Electric transmission lines contacted branches of a gray pine tree, Wagner said.

All four companies deny responsibility for the fires, Wagner said, but he noted that lawsuits filed by his office against the companies settled comparatively quickly.