At least four of the eight people killed in Monday morning’s boat dock fire in northeastern Alabama were children ranging in age from 7 to 16, a coroner said Tuesday.

The other four who died at Jackson County Park Marina at Guntersville Lake are presumed to be adults, county Coroner John Jordan said. The victims’ names have not been released, and dental records are being used to identify the remains, he said.

The fire, starting not long after midnight, tore through numerous boats that were docked at the lake. Some of the boats were occupied, and the flames forced several people to jump into the water to escape.

Some of the roughly 35 destroyed vessels were houseboats where people lived full-time. Seven people swam to safety or were rescued, and were taken to a hospital for treatment, officials said.

Investigators are trying to determine what caused the fire. Recovery efforts could last several days, the Scottsboro Fire Department said.

‘People … were jumping into the water’

Firefighters arrived around 12:40 a.m. local time Monday to a chaotic scene, Scottsboro Fire Chief Gene Necklaus told HLN.

“People … were jumping into the water, either off the back of their boats or retreating to the end of the dock just trying to avoid the fire before they had to,” Necklaus told HLN’s Robin Meade on Tuesday. “Several people would pile up in a boat, it appears, and then try to push away from the dock.

“But boats were burning, floating off, bumping into each other and setting other boats on fire just as fast as you can imagine.”

The fire’s location — on a covered dock that extended well out into the lake — made it difficult for firefighters to access, Necklaus told reporters a day earlier.

The dock collapsed. Some boats sank at the dock and some floated away before sinking, Necklaus said.

“Those boats burn at such a fast rate, and in that environment with the (dock’s) wood structure and the full roof, that fire spread so quick, so much quicker than you can imagine,” Necklaus told HLN on Tuesday.

Authorities said late Monday afternoon that it appears everyone is accounted for, although that will not be finalized until all the boats have been removed from the water and inspected.

Salvage workers returned to the lake Tuesday, hoping to ensure all victims have been accounted for as they lift sunken boats and clear away debris.

Shane O’Neal, owner of Southern Marine Towing & Salvage, told CNN affiliate WAFF that his team lifted one vessel Monday that had four bodies inside.

The seven people taken to a hospital were treated and quickly released, the fire department said. Some had minor injuries or minor hypothermia from the cold water.

The Bureau of Alcohol, Tobacco, Firearms and Explosives joined agencies from across the state to investigate.