Firefighters in the southwestern U.S. state of Arizona say they are making progress against the state's second largest wildfire ever.

Officials say they expect to have the huge fire 10 percent contained Monday.

The Wallow Fire has destroyed nearly 30 homes since it began on May 29. Over 4,300 firefighters are working to put out the blaze, which has so far cost $27 million to fight.

On Sunday officials began allowing evacuees from the towns of Springerville and Eager to return to their homes despite lingering air quality concerns. However, residents in the mountain towns of Greer, Alpine, and Nutrioso may not be allowed back for several more days.