ST. MARYS — A blanket of smoke hung over much of Camden County Tuesday morning and stretched up to Jekyll Island as a wildfire that has consumed more than 140,000 acres continues to rage in the Okefenokee National Wildlife Refuge.

The fire was threatening more than 250 homes Tuesday, forcing the mandatory evacuation of more than 1,000 residents in the southern half of Charlton County.

Nearly 700 firefighters from across the nation continue to battle the lightning-sparked wildfire since it was discovered April 6 burning in the wilderness area of the refuge.

A DC-10 air tanker capable of dumping 12,000 gallons of retardant was assigned to the blaze, making two-hour turnarounds from Chattanooga, Tenn., throughout the day. The goal was to protect homes threatened by the fire since it broke containment lines around the perimeter of the wildlife refuge.

A full compliment of aircraft and ground crews have been assigned to maintain and reinforce fire containment lines where the blaze is threatening to escape, including two 20-person hot shot crews, nine helicopters, 69 wildland fire engines 42 tractor plows and six bulldozers.

The U.S. Department of Homeland Security has authorized federal funding available to reimburse the state for up to 75 percent of the costs to battle the blaze. Eligible costs include labor, equipment and supplies to fight the fire, as well as emergency work such as evacuations, sheltering, police barricading and traffic control.

Federal fire management assistance is provided through the President’s Disaster Relief Fund and made available by FEMA to fight fires that threaten to cause a major disaster. Eligible state firefighting costs covered by the aid must first meet a minimum threshold for costs before assistance is provided, according to FEMA officials.

“FEMA recognizes all the hard work put in by firefighters and emergency response workers in extremely difficult circumstances,” said FEMA Region IV Administrator Gracia B. Szczech. “These funds will assist Georgia with costs associated with fighting the fire and help protect lives and property.”

Camden County Sheriff Jim Proctor said some of his deputies have been assigned to help Charlton County officials deal with public safety. Proctor said several of his deputies are Charlton County residents.

The forecast for the week calls for above normal temperatures and very dry conditions, creating a high risk the fire could lose control.

A Red Cross shelter capable of housing up to 300 people has been set in Kingsland at the Camden County Recreation Center.

Highway closures include Georgia 121 from the wildlife refuge to Georgia 94. Georgia 94 is closed from Georgia 121 to Georgia 185. Georgia 177 is closed 11 miles north of Stephen C. Foster State Park, which is also close.

Burn bans have been imposed in Camden and Charlton counties in Georgia and Nassau and Baker counties in Florida.

Most of the refuge is closed, but Kingfisher Landing on the East side remains open for day use and Okefenokee Swamp Park in Waycross remains open.