Last Updated 6:15 p.m. ET
GAINESVILLE, Fla. A long line of cars and trucks collided one after another early Sunday on a dark Florida highway so shrouded in haze and smoke that drivers were virtually blinded. At least ten people were killed, and another 21 were treated at local hospitals, reports CBS affiliate GTN-TV in Gainesville.
Visibility was so poor that when rescuers first arrived, they could only listen for screams and moans to locate victims, police said.
Authorities were still trying to determine what caused the pileup south of Gainsville on Interstate 75, which had been closed for a time because of the mixture of fog and heavy smoke from a brush fire. At least five cars and six tractor-trailers were involved, and some burst into flame.
Photographs of the scene revealed a gruesome aftermath, with twisted, burned-out vehicles scattered across the pavement and smoke still rising above the wreckage. Cars appeared to have smashed into the big rigs and, in one case, a motor home. Some cars were crushed beneath the heavier trucks.
Reporters who were allowed to view the site saw one tractor-trailer that was burned down to its skeleton, charred pages of books and magazines in its cargo area. Bodies were still visible inside a burned-out Grand Prix. The rubber on the tires of every vehicle had burned away, leaving only steel belts.
State police estimated that wreckage was strewn for nearly a mile in both directions.
Donna Henry was driving south at 3:45 a.m. when she encountered the dense smoke.
"We just hit it, and you couldn't see anything," Henry told The Gainesville Sun. She was driving with friends back home to Palm Bay.
Her car struck a guardrail and ended up sideways in the outside lane. She pulled off the highway and called 911 while listening to the sound of the other crashes on both sides of the busy road.
"You heard like 15 times somebody hit, from this side and that, north and south. It was bad."
All six lanes of the interstate which runs virtually the entire length of Florida remained closed at midday as investigators surveyed the site and firefighters sprayed foam on the wreckage to put out the last of the fires.
At least 18 people were hurt.
At some point before the pileup, police briefly closed the highway because of the fog and smoke, which came from a fire in the Paynes Prairie area south of Gainesville. The road was reopened when visibility improved.
Florida Highway Patrol Lt. Patrick Riordan said he was not sure how much time passed between the reopening of the highway and the first crash.
Traffic was being diverted onto U.S. 301 and State Road 27, Riordan said.
Four years ago, heavy fog and smoke were blamed for another serious crash.
In January 2008, four people were killed and 38 injured in a series of similar crashes on Interstate 4 between Orlando and Tampa, about 125 miles south of Sunday's crash. More than 70 vehicles were involved in those crashes, including one pileup that involved 40 vehicles.