By RUSS BYNUM

Associated Press

MONTROSE, Ga.

--More than two dozen cars, pickup trucks and tractor-trailers collided Wednesday morning in a fiery pileup on a foggy Georgia interstate, killing at least four people and sending nine others to a hospital, officials said.

Work crews on Interstate 16 were still clearing charred and twisted wreckage from the crash scene, which covered nearly a quarter-mile of the roadway, hours after the chain of crashes occurred at about 8:10 a.m.

Crews initially reported three deaths before finding another person dead in the wreckage later Wednesday.

The Georgia State Patrol was still trying to piece together what started the series of wrecks involving 27 vehicles.

Capt. Kirk McGlamery said even drivers who dodged to the side of cars crashing in front of them weren't safe from getting rear-ended off the highway's shoulder.

"It was just a chain reaction," McGlamery said. "I talked to two individuals involved who had come to a stop and had pulled off, one was on the shoulder and the other was trying to get out of the way, when they were struck by vehicles coming up behind them."

Officials said poor visibility likely played a big part. Weather forecasts called for dense fog Wednesday morning, and McGlamery said motorists reported smoke across the highway.

He said a controlled burn had been permitted nearby the day before, and troopers were trying to find out if burning continued into Wednesday.

The crash shut down I-16 in both directions for several hours, though a single eastbound lane had opened Wednesday afternoon. The highway covers only 170 miles between nearby Macon in central Georgia and Savannah on the coast.

But it's heavily traveled by commercial trucks hauling goods between Atlanta and Savannah's busy seaport, and is often used by travelers as a route to Interstate 95 along the Eastern Seaboard.

McGlamery said seven tractor-trailers were involved in the pileup, including an empty fuel tanker. Fumes inside the tanker exploded and caught fire, though the driver of the rig survived.

Laurens County EMS director Terry Cobb, who was among the first emergency officials at the scene, said at least six vehicles were still on fire when crews arrived. Emergency officials encountered fog on the way to the crash site, though it seemed to lift one they arrived, Cobb said.

The area was under a dense fog advisory at the time of the pileup, said Laura Belanger, a meteorologist at the National Weather Service in Peachtree City.