8 hurt in Norfolk explosion

The blast occurred around 12:30 p.m. as a construction crew worked on the heating and air conditioning system at 28 Wildwood Road, an unfinished section of a duplex at the Village at River’s Edge, a new development for residents 55 and older.

The force of the blast sent building materials flying into the air and on top of the worker, who was trapped under fire and falling debris inside the basement, and was screaming for help.

“He was trapped under an extraordinary amount of rubble, but we were able to communicate with him,’’ said Franklin Deputy Fire Chief Paul Sharpe, who was among the first responders to arrive at the scene and keep the victim talking until firefighters finally freed him.

“We could see half his body,’’ Sharpe continued, “and he was saying he wanted to get out.’’

Responders from 17 different communities assisted at the scene.

The victim, whose identity was not released, was transported by medical helicopter to Brigham and Women’s Hospital in Boston, along with another construction worker. The trapped man, who had severe burns, was on life support last night suffering from grave injuries, said a fire official with direct knowledge of the investigation who requested anonymity because he was not authorized to speak about a medical condition.

The other victims are two firefighters, three other construction workers, and the female resident who lives at the adjoining unit on Wildwood Road. Authorities did not release their names or medical conditions yesterday.

The cause of the blast remained unknown yesterday, and firefighters vowed a vigorous investigation. The state fire marshal, Norfolk police, and the federal Occupational Safety and Health Administration are also investigating.

“This investigation is going to take some time, and it will go in two directions — interviewing witnesses and collecting physical evidence,’’ said Fire Marshal Stephen D. Coan.

Coan say there was no natural gas service to the property, but residents say they share propane tanks that are buried along the property.

A marketing representative for the Village at River’s Edge said the blast occurred as the construction crew worked on a heating and air conditioning system at 28 Wildwood.

“It appears as if it was a construction-related incident from the information I have,’’ said Al Rao, the representative. “Our main concern is for the health and well being of the workers who were involved. Our main hope is they will recover from their injuries.’’

Authorities would not comment on the source of the explosion or whether workers may have triggered the blast.

As crews put out the final flames, firefighters described an “overwhelming’’ scene when the first group of responders arrived yesterday afternoon. They were confronted by heavy smoke and flames, people trapped inside, and building debris everywhere.

The building materials came down “like pixie sticks,’’ said Sharpe.

Firefighters got to work quickly, with help from bystanders — including a retired fire chief — who grabbed hoses and tried to put out the flames. But they found their most seriously wounded victim trapped underground begging for help.

“The condition on the scene was overwhelming at that point,’’ said Norfolk Fire Chief Cole Bushnell, who praised the heroics of the many fire departments that responded to the scene.

Dennis Dowd, the retired fire chief who lives in the complex, said he was not trying to be a hero, but only lending a hand.

“They looked like they were pretty busy,’’ he said, “so I just helped them get water from a hydrant to a pump.’’

Patricia Kiggen, a neighbor, said she and her husband heard and felt the explosion.

“It was a booming sound that shook the whole house,’’ she said. “Papers and insulation were flying from the sky. It was awful.’’

Globe correspondents Stephanie Daly and L. Finch contributed to this report. Meghan Irons can be reached at mirons@globe.com; Guilfoil at jguilfoil@globe.com