Cobb County police are looking for dash camera footage from motorists who witnessed the massive pileup Thursday afternoon on I-75.

Traffic investigators believe a single northbound vehicle hydroplaned near Big Shanty Road and hit a guardrail, causing several crashes in a chain reaction that picked up 16 other vehicles. A truck driver, 58-year-old Boniface Ndiangui of Marietta, was killed.

The interstate was shut down for more than seven hours while authorities worked to clear the mangled vehicles, some of which caught on fire.

Heavy rain was falling when the first wreck was reported shortly after 11 a.m. The National Weather Service had just lifted a dense fog advisory for metro Atlanta, but a layer of low clouds remained. Drivers described nearly white-out conditions.

As traffic slowed, a second crash involving two tractor-trailers and a passenger car occurred in the backups, according to Cobb police spokesman Sgt. Wayne Delk. Thirteen more vehicles wrecked as a result, including Ndiangui’s tractor-trailer, he said.

“You could only see about 40 yards in front of you,” Chris Hill, a truck driver who saw the crash, told Channel 2 Action News. “The truck to my right got rear-ended, broke the axles, destroyed it. Luckily, I didn’t get tangled up in that.”

Others weren’t as lucky. According to police, two tractor-trailers, three cars, three passenger vans and five pickup trucks, some of them towing trailers, were also involved in the fatal wreck.

Ndiangui was driving a white Freightliner cab and towing an enclosed semi-trailer when he rear-ended a black Ram pickup towing a car hauler, Delk said. He was dead at the scene.

“There were other involved motorists that sustained non-life-threatening injuries during the collision,” the police spokesman said.

The wreck remains under investigation. Anyone who has video footage is asked to contact Cobb’s traffic investigation unit at 770-499-3987.