PORTLAND — Three people were injured in two separate boat explosions Friday, one off East End Beach in Portland, the other in the Kennebec River in Gardiner.

Authorities say both explosions were likely caused by gasoline fumes igniting.

In Portland, one person was taken to a hospital after the explosion on a 20-foot pleasure boat just before noon. Witnesses said it looked and sounded like a bomb.

“It was a huge explosion. Big flames, big noise,” said Masoud Kankash of Massachusetts, who was visiting Portland with his wife and was on the East End Beach dock when the boat erupted.

“I see the gentleman trying to put gasoline in it, I think. All of a sudden, explosion. The gentleman just jumped in the water,” he said.

Flames climbed higher than the 12-foot piling at the rear of the boat, where the fire was concentrated, he said.

Jan Martin, who was waiting for the ferry leaving from a nearby pier, saw the man, who was wearing shorts and a T-shirt, walking out of the water and a woman calling to him.

“She was pretty upset … screaming to him to get away from it,” Martin said. “He was like, ‘I’m OK. I’m all right.’ “

“When she yelled at him, I was surprised he was alive,” Martin said.

He said people in another boat recovered the engine cover more than 100 yards away.

The man, whose name was not immediately available, was taken to Maine Medical Center for treatment. His wife, who was also at the boat launch, was not injured.

Deputy Fire Chief David Jackson said the explosion appeared to be the result of gasoline fumes ignited by something on board, possibly equipment that was running.

The man told Jackson he had removed the engine cover of the boat and was looking into the engine compartment when it exploded.

The man suffered injuries to his face, chest, hands and legs, with his skin reddened like a bad sunburn, which would indicate first-degree burns. Blistering would indicate second-degree burns, Jackson said.

Fire injuries can appear mild initially and then worsen, he said, especially if the victim inhales burning vapor.

Jackson said it was a good sign that the victim was able to talk with firefighters without difficulty.

There is no fuel supply on the dock, but it is common for people to launch their boats at the ramp in that spot and then start the motor. If the boat has a fuel leak and fumes accumulate inside the bilge or engine compartment, that could fuel an explosion.

Boating safety experts advise boaters to turn on the blower, if their boat is equipped with one, to vent any fumes that may have accumulated.

Firefighters worked to douse the fire but it kept burning, probably fed by the boat’s gasoline supply, Jackson said. Firefighters at one point smothered the flames with foam.

“I thought it was a bomb because I have never seen a black cloud of smoke like that,” said Amanda Ek, who was sunbathing at the popular waterfront park. “I did see (the victim) in the water. He was just kind of floating and trying to swim.”

“It sounded like a cannon,” said Eliot Felde, who was at the park with a friend. He said there were flames, and he could see the heat rippling the air as it rose from the red and white speedboat, named “Instigator.”

The department’s fire investigator will try to determine the exact cause of the explosion after talking to the victim and studying the boat’s wreckage, Jackson said.

In Gardiner, firefighters used foam to suppress the gasoline fire that kept re-igniting the boat. All four people on board jumped into the river after the explosion and were picked up by another boater, investigators said.

Two women, Vickie Massey and Liliane Davidson of Oakland, were taken by ambulance to MaineGeneral Medical Center in Augusta.

Sgt. Ken Grimes of the state Fire Marshal’s Office said it appeared their injuries were not life-threatening.

Also on the boat were Jeffrey Massey and Howard Davidson. Grimes said the boat is owned by the Masseys, who live in Oakland, and had been in the water several times this season.

Grimes said the women were sitting in the back of the boat, on either side of the engine compartment, and the men were in the front of the boat. They planned to cruise to Boothbay Harbor, he said.

Marine Patrol Sgt. Rene Cloutier said the fire could have originated after gasoline ended up in the bilge during fueling and was ignited by a spark from starting the engine. Cloutier said that on extremely hot days, more gasoline vaporizes, which can increase the risk.

Terry Malloy of Augusta, who was fishing near the landing for stripers, said the people had launched the boat and drifted out into the channel.

“I heard a loud bang and explosion and heard everybody hollering, ‘Get off the boat! Get off the boat!’ ” Malloy said.

He called 911 for help and then watched as the flaming boat headed south down the river and drifted ashore in Pittston, just beyond the Randolph town line.

Firefighters from Randolph and Pittston used foam to put out the blaze on the fiberglass boat.

– Kennebec Journal Staff Writer Betty Adams contributed to this report.

David Hench can be contacted at 791-6327 or at:

dhench@pressherald.com