ROXBURY - A fuel container being used to start a campfire exploded late Friday night, spraying burning fuel 50 feet and enveloping an 8-year-old boy in a fireball.

Michael Martin of Strong was standing 8 feet away when the fuel container exploded in his father's hand, said Sgt. Joel Davis, a state fire investigator.

The boy took the brunt of the fireball, suffering second- and third-degree burns to 40 percent of his body - his abdomen, hands and legs, Davis said.

The accident happened at the family campsite at the home of Martin's grandfather, James Gallant of 2025 Roxbury Road, also called Route 17.

Martin was rushed by personal vehicle to Rumford Hospital, where he was initially treated. Mexico-based Med-Care Ambulance drove the boy to Massachusetts General Hospital in Boston because medical helicopters were grounded by thunderstorms, Roxbury Fire Chief Ray Carver said.

A woman who answered the phone on Saturday evening at the Boston hospital deferred all calls regarding Martin's condition to the boy's mother, Amy Martin, who was unavailable. She and husband Timothy Martin, of 36 Lambert Hill Road in Strong, are with their son, Davis said.

"This was a freak accident," Davis said. "It was one of these million-to-one odds. He was in the wrong place at the wrong time, but he was a safe distance away for starting a campfire."

Davis said investigators did not know what kind of accelerant Timothy Martin was using to start the fire. Until test results come back from the lab, they're presuming it to be diesel kerosene.

Davis said they are also investigating the new-model safety container that Timothy Martin was holding by the handle when it exploded.

"When vapors build up inside a container, any ignitable liquid can explode under the right conditions," Davis said. "The vapors inside had to be at the perfect mixture of fuel and air."

Unlike older-model safety fuel containers, the new one didn't have a vent through which vapors could escape, he said.

When the container ruptured, the blast blew away from Timothy Martin and sprayed in his son's direction, Davis said.

Gallant and Timothy Martin suffered minor burns to their hands and were treated at the scene.

Carver said accelerants should never be used to start campfires.

"You shouldn't use any accelerants, not even charcoal lighter fluid. That's designed for charcoal, not wood," he said.

Davis said he didn't expect any charges to be filed, "unless there's something we don't know about yet. We just want to make sure the little guy gets better."

tkarkos@sunjournal.com