The fire started about 9 p.m. after Jason Chad Smith, 46, of Knoxville, reset a tripped circuit breaker on his cabin cruiser that was docked at the marina, according to the Tennessee Wildlife Resources Agency.
An explosion set the boat ablaze, and the flames spread from there, consuming ten boats and part of the dock. The fire damaged another eight boats, the TWRA said.
Smith suffered burns that officials described as serious but not life-threatening. He was ultimately taken to the Vanderbilt Burn Center in Nashville.
The Karns Fire Department responded to the fire.
Karns Fire Chief Daron Long said there were multiple boats burning when fire crews arrived and it was deemed too dangerous to send firefighters onto the floating dock for an offensive attack.
"We had propane tanks exploding on the boats," Karns Fire Chief Daron Long said. "The big thing is, the boats were so close together. So one catches fire and it spreads quickly."
The firefighters opted instead to take a defensive position on the shore, using an aerial ladder truck. No firefighters were injured.
“Personnel safety in that situation is paramount,” Long said. “The public was not at risk.”
The TWRA is working with the Knox County Sheriff's Office to determine the cause of the explosion.