The cause of a Pine Nut wildfire that cost more than $1 million to fight may never be known.
East Fork Fire District Investigator Capt. Terry Taylor said leads have been exhausted in determining the cause of the Carter Springs fire.
He said Tuesday the fire was accidental, but there were two equally possible sources for the blaze.
The fire National Interagency Coordination Center reported Tuesday morning that the 3,454-acre fire cost $1.1 million to fight so far.
At one point, nearly 300 firefighters were battling the blaze with the help of 10 air tankers.
Taylor said investigators were able to track the source of the fire to an 8-inch diameter and the ignition time to within 90 minutes of the first report.
But with those parameters, two possible sources remain, a cigarette from a group of motorcyclists parked at the location or a vehicle fire.
"We've tested both in the field and either one was enough to ignite the cheat grass in the drainage ditch," he said.
Taylor said he eliminated arson and NV Energy equipment as a source for the fire.
"A cigarette could have started it," he said. "It also looked like someone had a small fire under the hood of a vehicle and kicked something out. Some molten material ended up in the brush."
Douglas County Sheriff's deputies and Nevada Highway Patrol troopers helped track down leads in the investigation.
"They were great in generating interviews," he said. "It's the beauty of living in a community like this."
Taylor warned residents to be careful with cigarettes near vegetation, which is very dry after a long, dry summer.
NV Energy Spokesman Karl Walquist said the utility de-energized a power line as a safety precaution that knocked power out to 420 customers. Electricity was restored by 2 a.m. Saturday to most of the customers. All but two had power restored by Saturday evening.
Walquist said the fire damaged 22 power poles and 5,800 feet of cable.
Four utility crews worked to rebuild the line starting early Saturday morning. They were done by Monday afternoon and the damaged line was re-energized.
The fire was declared contained on Monday evening a day ahead of schedule and is expected to be extinguished by Saturday.