The mystery is over.
Authorities say the haze spreading over Charleston and parts of Berkeley County today is from a controlled burn of about 400 acres of private property off Cainhoy Plantation Road.
The smoke has baffled residents, some of whom reported two dark plumes of smoke coming from near the Daniel Island area.
Multiple state and federal officials said they didn't know where the smoke originated. The South Carolina Forestry Commission this afternoon confirmed the controlled burn on Point Hope Island, north of Daniel Island and south of Cainhoy.
Late last month the National Weather Service issued multiple thick smoke advisories in connection with a controlled burn at the Francis Marion Forest, but no such advisories had been issued today.