Nevada fire no threat to residents

RENO, Nevada (CNN) -- More than 2,200 firefighters continued to battle a blaze Sunday that has burned 14,500 acres in the past week just west of Reno, Nevada.

The Martis fire -- named for the region where it started -- is 50 percent contained, but Fire Information Officer Deborah Walker said steady winds from 15 to 25 miles per hour, with gusts up to 40 mph, are a main concern.

The wind not only threatens to spread the fire, but could also blow the air tankers off track. At least seven air tankers dropped flame retardants on the fire on Saturday -- a costly, but effective way to contain the fire.

"The aircraft is very expensive, running anywhere from up to $7,000 an hour for a single air shipment," Walker said.

So far, the air tankers have cost $6 million to battle the Martis fire.

There is no threat to residential communities, Walker said. The fire is about one-and-a-half miles from the nearest home in Incline Village, near Lake Tahoe.

Investigators are still not sure exactly what caused the blaze. Last Saturday, firefighters contained a blaze, started by an abandoned campfire. The next day, the Martis fire began in close proximity, near the populated area of Hirschdale.