A wildfire burning about 5 miles east of the Nogales, Ariz., airport has charred about 450 acres, officials said Saturday.

The Soldier Basin Fire was burning in steep rocky terrain. It’s burning mainly grass and brush.

There are no structures immediately threatened, according to a news release from the Coronado National Forest.

About 150 people are assigned to the fire. Also being used are five air tankers, two helicopters, 12 engines and seven water tenders.

The fire was human caused.