About 100 firefighters and support personnel have been battling a wildfire Thursday that has charred more than 8,000 acres near the Snake River southwest of Boise. No structures have been threatened, and no one has been injured.

"They've got most of the active flames knocked down," said Mallory Eils, fire information officer for the Bureau of Land Management.

The cause of the fire has not yet been determined, but investigators believe it was human caused. It started near the river.

The fire is burning south of Swan Falls Dam and Celebration Park, about 4 miles north of Murphy. The fire was reported at about 9 p.m. Wednesday, Eils said.

The fire, which has been dubbed the Con Shea Fire, is likely larger than 8,000 acres but BLM officials won't have a new estimate on its size until Thursday night.

Resources dedicated to the fire Thursday include: four tanker planes, eight BLM engines, one Department of Lands engine, and firefighters from Murphy-Reynolds and Melba.