HOOKSETT – A firefighter who was trapped inside Mow Town Power Equipment during a three-alarm fire Monday night has been taken to Massachusetts General Hospital for treatment of burns, a fire official said.

"A garage door came crashing down and trapped him inside the fire area," Deputy Fire Chief Michael Hoisington said. "It's minor burns."

Another firefighter injured his shoulder trying to save the trapped firefighter, Hoisington said. Both firefighters are from Hooksett.

A third firefighter from Manchester suffered a concussion when an explosion knocked him to the ground near a building entryway, Hoisington said.

Fire officials did not release the identities of the firefighters after repeated inquiries Tuesday.

►Three firefighters hurt as fire ravages business (19)

Hoisington said the three firefighters were taken to Elliott Hospital in Manchester. Two were released, but the burn victim was later taken to MGH in Boston by ambulance. All injuries were considered non-life-threatening.

Witnesses reported hearing numerous small explosions, which fire officials attributed to propane tanks and gas-fueled equipment that were inside the building.

"It was way up high, 30 or 40 feet," said David Farrand, who lives across from the business on Route 3A. "You could hear, 'Bang, bang, bang.'" The roadway was closed all night as firefighters worked on the blaze.

Hoisington said fire walls inside the building did their job, containing the flames to where the fire erupted and preventing them from spreading. The concrete building was separated by multiple work units.

"The fire walls held pretty well. The fire was contained mostly to one unit and went through the roof," he said.

Fire investigators were on scene all day yesterday but did not release an official cause.

Mow Town owner Mark Manzella said he was inside the building when he noticed the flames on a workshop bench. He grabbed a fire extinguisher, but was unable to put out the fire.

"I emptied both fire extinguishers and just left," Manzella said.

No one else was inside the building, he said.

Manzella and his former wife, Carrie Manzella, opened Mow Town about seven years ago. The business sold small engine parts and lawn care equipment and employs five people.

Hoisington said the extent of the damage was unclear but some of the property might be salvageable.