TITUSVILLE, Fla. -

Two people, including a 75-year-old man, were injured Monday morning when a 31-foot boat exploded at a Titusville marina, officials said.

The 1987 Wellcraft boat exploded about 11:40 a.m. on Marina Road at the Titusville Municipal Marina.

The owner of the boat, 68-year-old Leon Lincoln from Christmas, was taken to Parrish Medical Center in Titusville with some lacerations. The passenger, 75-year-old Philip Pendleton, from Titusville, was airlifted Holmes Regional Medical Center in Melbourne in stable but guarded condition.

The Florida Fish and Wildlife Conservation Commission said the men had just finished fueling the boat, which was tied to the fuel dock.  FWC officials said the blowers were turned on to clear any fumes, but the boat blew up on the third attempt to start the starboard motor.

One of the dockmasters who assisted with the fueling was knocked back from the impact of the explosion but was not hurt.

The men had left Kennedy Point Marina earlier and had stopped to fuel up.

"Something ignited the fumes that were on the vessel," said Richard Jefferson of the FWC.

Witnesses said the explosion happened so fast everyone heard it before they saw it.

"It sounded like the shuttle coming in," said Joe Mazurek. Another witness described how loud the sound was as the boat exploded.

"I can't hear out of my right ear-put it that way," said Jeff Bengerbresten.

Video from Local 6 news helicopter Sky 6 appeared to show the top half of the boat resting in the water while leaning up against the bottom half of the boat.

Investigators are trying to figure out what caused the explosion as they towed the boat up to shallower water on Monday afternoon.

Watch Local 6 for more on this story.