The Mill Hollow fire burning in Duchesne County continues to expand, jumping from 533 to 668 acres on Friday.

U.S. Forest Service information officer Venetia Gempler said additional crews were added to manage the blaze, which is being fanned by winds and fueled by bug-killed deadfall in the area. The fire, ignited by a single lightening strike, has been burning since June 23.

The Mill Hollow fire is under a fire management procedure that controls a naturally ignited fire while allowing it to burn to control dangerous levels of fuel load.

Also, a firefighter who was airlifted to the University of Utah Medical Center on Thursday was held for observation and released Friday morning. A U.S. Forest Service statement said his injuries were not as serious as first reported on Thursday.