Firefighters used bulldozers Monday to widen fire breaks that were protecting a small community from a wildfire that had blackened more than 86 square miles of forest in southeast Georgia.

The fire, started April 16 by a fallen power line that ignited tinder-dry trees near the sprawling Okefenokee National Wildlife Refuge, was about 45 percent contained after burning some 55,600 acres, officials said.

"It's not directly a threat at this time," said Byron Haire, a spokesman for the Georgia Forestry Commission.

It was about 10 miles southwest of Waycross and about five miles south of Manor, where firefighters were using bulldozers to broaden fire breaks from 6 feet wide to 20 feet.

Eighteen homes have been destroyed, officials said.

No more evacuations had been ordered since about 1,000 people near Waycross were forced to flee their homes last week. Authorities urged about 5,000 others to evacuate voluntarily because of possible health risks from smoke inhalation.

Ware County schools remained closed Monday because of concern about smoke reducing visibility on roads used by school buses. The schools have been closed since last Tuesday.

Southeast Georgia is extremely dry, with rainfall deficits of 6 to 8 inches for the year.

"We are really just praying for rain," said Eric Mosely, a spokesman for the Georgia Forestry Commission.

During the weekend, smoke extended north to Chattanooga, Tenn., more than 350 miles away.