One westbound lane of Interstate 16 remained closed early Thursday, a day after 27 cars and trucks collided in a fiery pileup.
Georgia Department of Transportation officials said the right, westbound lane is expected to be closed until noon Thursday.
The chain-reaction accidents around 8:10 a.m. Wednesday killed four people and sent nine others to a hospital.
Georgia State Patrol operator Terri Graffagnino said a trooper was out all night checking for lingering smoke from controlled burns in the area. She said the trooper has been patrolling overnight from mile markers 36 to 54, where fog routinely gets thick.
Dense fog was reported in the area Wednesday morning. Georgia State Patrol Capt. Kirk McGlamery said motorists also reported smoke across the highway.
Meanwhile, G-DOT said a crew was on the way to place signs warning of low-visibility on Interstate 16 when cars began crashing.
DOT spokeswoman Jill Goldberg says a call from a 911 operator Wednesday morning saying motorists were complaining about driving conditions prompted the agency to dispatch a crew with caution signs from Dublin, about 10 miles from the crash scene.
Goldberg says less than 30 minutes elapsed between the operator's call and the pileup.