Home video of the explosion | 11 News report

Two people were seriously burned Sunday evening when their boat exploded in the South Shore Harbour Marina in League City.

The thick, black smoke and flames billowed out of the boat, which was being repaired and sold when witnesses said a fuel vapor in the home ignited.

Two men were working inside when it happened, a 17-year-old and a 34-year-old. Both suffered second- and third-degree burns.

Home video

A witness shot this home video right after the explosion.

Two LifeFlight helicopters arrived just minutes after the blast. Had it not been for two witnesses in particular, there may not have been anyone left to save.

"It was bad," witness Brenda Nugent said. She saw the explosion and is a nurse.

"The one guy was just stumbling down the dock, and I put water on him right away because his hair was smoking," she said. "And the mechanic ran and pulled the other guy out of the water, and we put water on him. Then the ambulance arrived."

Keith Emmons said he saw it coming.

"We were smelling gasoline fumes during the day when they were working on it," he said. "So we were kind of worried about that, and when we felt explosion, I knew exactly what had happened."

Emmons said fuel had been leaking into the hull of the boat. Fire investigators are trying to figure out how that may have ignited.

At least five other ships were damaged in the fire.

Nugent said the two men in the boat may have never survived if it wasn't for a man she doesn't even know, who jumped into the fire and burned his own face trying to save them.

"Everybody ran away, and he ran to it," she said. "All I know is his name is Alan. He's a real hero."

The Coast Guard set up boons to make sure the fuel didn't leak out of the marina.