Fire destroyed two boats and damaged a third on Lake Ray Hubbard on Friday evening, but quick-acting volunteers managed to save several others.
The fire started shortly after 5 p.m. at Bayview Marina.
The first boat caught fire while a family was refueling the 27-foot motorboat. They jumped ship and sent it adrift, said Dallas Fire-Rescue spokesman Jason Evans.
Other boaters raced to help stop the flames from spreading.
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Tyler Roesle said he was nearby when he noticed the smoke.
"It was just engulfed," he said. "I got the hose."
Roesle, who recently graduated from a fire academy and is looking for work as a firefighter, said he and several other volunteers managed to save four boats from catching fire.
The flames were intense, he said.
"I'm going to have blisters on my hands," he said.
John Dell quickly joined Roesle and focused on the first boat that was ablaze.
"We were actually able to get a pole and push that boat out away from the boats," Dell said. "It was just making its way from one boat to another, setting them on fire."
The Dallas and Garland fire departments arrived on the scene and extinguished the fires.
Dallas Fire-Rescue said the exact cause has not been determined but the fire is being investigated as accidental.
"Considering that there was nobody piloting that boat that was on fire, we feel like we got extremely lucky," Evans said. "It could have been a lot worse."
Two people were treated on scene for non-life-threatening injuries, he said.
NBC 5's Amanda Guerra contributed to this report.