ATLANTA - Wildfires near the Georgia-North Carolina line are spewing smoke so thick that residents are being urged to wear special masks if they must do outdoor activities.

The fires - many of them suspected arsons - have prompted evacuations in Georgia, North Carolina and Tennessee in recent days.

The largest of dozens of ongoing wildfires in the South has now burned 13,300 acres, more than a third of the vast Cohutta Wilderness area, in the north Georgia mountains just south of the Tennessee line.

Get Breaking News Delivered to Your Inbox

Fire managers said Saturday that the blaze, believed to have ignited from a lightning strike in mid-October, was only 20 percent contained.

CBS Augusta affiliate WRDW-TV reports officials are beginning to worry about air quality and people’s health in the area. While the best option may be to stay indoors to avoid what could become the largest wildfire in Georgia history, sometimes that’s just not feasible.

In Macon County, North Carolina, special health masks were being made available Saturday. Emergency Management Director Warren Cabe said they’re distributing N95-rated masks as regular surgical masks don’t provide adequate protection from smoke particles.

And yet, the drifting smoke that prompted air quality authorities to declare a Code Orange on Friday in Charlotte, North Carolina, cleared enough for Saturday’s Charlotte Marathon to be run as planned under crisp blue skies.

CBS Raleigh affiliate WNCN reports evacuations were ordered in a sixth North Carolina mountain county on Saturday and masks are being handed out while at least 20 wildfires continue to burn.

More than 1,000 firefighters are now battling the wildfires that have burned more than 23,000 acres in western North Carolina, officials said Saturday afternoon.

Kristen Butterfield, who works at a local shop in Chimney Rock, North Carolina told the Asheville Citizen-Times that around noon Friday authorities began ordering people to evacuate. Then she saw a structure catch fire.

“We had to get out,” she said. “They told us at noon and we were out by 2 p.m. at the latest. We took everything we could.”

Her friend Andre Whilden, who lives behind Chimney Rock village, said she and her husband hardly got any notice.

“We got everything packed that we could,” she said, which included seven animals.

Whilden said on Wednesday she saw one firetruck after another speed past her house and she knew the fire was getting worse.

“I didn’t expect to be evacuated,” she said. “I expected it to stay up on the mountain, but on Wednesday I knew something wasn’t right so I went down to the visitor’s center, looked to my left and the whole mountain was on fire.”

Smoke has settled over Clayton, Georgia and surrounding Rabun County, where fires including a 2,000-acre blaze has forced people from their homes. That fire is a suspected arson blaze, and the sheriff has asked residents to be on the lookout for a dark blue SUV seen in the area where the fire started on Wednesday.

In Tennessee, 42 of the 58 active wildfires in the state are suspected arsons - or about 72 percent of them - the Tennessee Department of Agriculture reported Saturday in its wildfire situation update.

In North Carolina’s Nantahala National Forest, more than 20 wildfires have burned more than 17,000 acres and all of them are “being investigated for suspected arson,” federal forestry officials have said.

The federal government has approved a request for money to fight the blazes in western North Carolina, Gov. Pat McCrory said. A grant from the Federal Emergency Management Agency will now pay 75 percent of the emergency protective measures taken in fighting the fires, McCrory said in a news release Saturday.

In South Carolina, the Easley Fire Department is asking residents to donate water, Gatorade and other drinks to help firefighters battling a wildfire on Pinnacle Mountain.