At least six people, including at least five children, were hospitalized with burns and other injuries Monday after an explosion on board the boat they were riding in near Edgewater, Md., authorities said.

Police and fire officials gave varying information on those hurt, though they said all were expected to survive.

Anne Arundel County Fire Department Division Chief Keith Swindle said six of nine people on board the boat were injured — a 9-year-old boy, a 9-year-old girl and a 13-year-old girl the most seriously. He said another ­9-year-old boy, 13-year-old girl and a woman also were hospitalized with injuries, and three other people on board the boat were unhurt.

But Sgt. Brian Albert, a Natural Resources Police spokesman, said in an e-mail that eight of the nine on board were injured, including six children. He said a 9-year-old boy and a girl whose age he did not know were the most seriously hurt, though two 13-year-old girls, a 12-year-old girl, a 9-year-old boy and two women were also taken to hospitals with injuries.

The incident occurred about noon, soon after the group had refueled its 32-foot Wellcraft boat at the Oak Grove Marina and headed out into the South River, Swindle said. He said the boat’s engine stalled and, as those on board tried to restart it, the explosion occurred. He said those who were injured sustained mostly burns from the explosion and ensuing fire.

Albert said that when the group left the dock, only one of the boat’s twin engines seemed to be functioning.

He said the boat made it about 100 feet into the river before the explosion.

Albert said investigators were exploring precisely what sparked the blast, but preliminarily, they thought the case to be “most likely an accident.”

He said it was possible that the boat’s blower system, designed to expel fumes from the engine compartment, had malfunctioned or that there was some sort of problem during the refueling.