A woman suffered first- and second-degree burns Wednesday when a boat caught fire in Harrison Bay Marina.

Firefighters, taking a break from training on the Chattanooga Fire Department's fire-rescue boat, were having lunch at the nearby Dockside Cafe when someone rushed in to report an explosion about 11:15 a.m., fire department spokesman Bruce Garner said.

"A husband and wife had reportedly just finished putting gas in their 28-foot cruiser and were pulling away from the dock when an explosion rocked the boat," he said. "There was a flash fire, and the woman jumped into the water to escape the flames."

By the time firefighters, onboard their fire boat, arrived at the damaged boat near the gas dock, an onboard fire suppression system already had extinguished the blaze, Mr. Garner said.

Firefighters saw Patricia Hall of Big Canoe, Ga., floating injured in the lake, he said.

"She was quickly plucked from the water," Mr. Garner said.

Rescuers transported Mrs. Hall to Memorial North Park Hospital. Hospital officials declined to comment on her condition.

Fire Lt. Dusty Rose said she sustained first- and second-degree burns to both legs, according to Mr. Garner, but her injuries were not thought to be life-threatening.

Mrs. Hall's husband, Paul, was onboard and uninjured, Mr. Garner said.

The fire damaged the fuel system on the boat, causing as estimated 10 gallons of gasoline to leak into the lake, he said. The hazardous materials team with Hamilton County Emergency Services placed a gas and oil containment boom around the spill and used absorbent pads to remove the gasoline, he said.

Tennessee Department of Environment and Conservation spokeswoman Tisha Calabrese-Benton said state regulators were not called out on the spill.

"If the county's hazmat crew boomed the area and used absorbent pads to collect the gasoline, the impact to the environment would be minimal," she said.

The cause of the explosion is being investigated by officers with the Tennessee Wildlife Resources Agency, Mr. Garner said.

Tennessee Wildlife and Resources Agency officer Matt Majors said the accident probably resulted from a combustion problem in one of the boat's two engines. Most pleasure boats have engine compartment ventilation systems, but they sometimes malfunction, Mr. Majors said.

Mr. Majors said the couple's 1987 cabin boat was "completely salvageable."

Staff writer Adam Crisp contributed to this story.