The Florida Forest Service is working to contain a 50-acre wildfire northwest of Baldwin in Baldwin Bay.
The bay is a 9000-acre swampy area off County Road 121, two miles north of U.S. Highway 90.
Officials said the fire was caused by lightning last week and smoldered in the deep muck for a while before the smoke was visible. When crews first arrived Sunday, the fire was 2 acres and smoldering in the duff.
The fire has jumped the containment lines twice and grown about 40 acres Wednesday, with the gusty winds and dry conditions, officials said.
Firefighters said they have the fire 25 percent contained. They said there are no homes in danger, but the thick column of smoke is visible for miles.
A helicopter is dropping water, and heavy dozers are working to carve deep fire lines on the ground, officials said.