Emergency crews yesterday were forced to raze four Brighton businesses after the block was engulfed in a fast-moving fire that caused $4 million damage and resulted in four firefighters being sent to the hospital.
The ruins of the one-story row of brick businesses at the corner of Chestnut Hill Avenue and Embassy Road were ordered demolished to allow National Grid workers to reach a gas line that leads to the building.
Fire officials said they believe the four-alarm blaze, which began about 6 a.m. and burned for more than seven hours, was partly fueled by the gas line, which was inaccessible except by excavation, said Fire Department spokesman Steve MacDonald.
“Underneath all that debris is pockets of fire, which we believe is being fed by gas,’’ said MacDonald, who expected crews to continue work at the scene today.
More than 100 Boston firefighters swarmed the building after a gas station attendant first spotted flames coming from a pizza restaurant, Bocca Buona, shortly before 6 a.m., MacDonald said.
Other businesses in the strip included a kosher caterer, a laundromat, and a janitorial supply store.
“No one will be able to retrieve anything from the building,’’ MacDonald said.
Four firefighters were injured; none of the injuries were life-threatening. One firefighter injured his eye and shoulder, while the others slipped and fell on ice.
Conditions were challenging, MacDonald said: When trucks first responded, the temperature hovered at 14 degrees. Much of the scene was obscured by huge billows of dense, acrid smoke. Firefighters were ordered out of the building after it was determined no one was inside, he said.
“There was [later] an explosion in the middle building, a janitorial supply place,’’ said Deputy Chief Robert Calobrisi.
Chemicals from that store caused the foul-smelling smoke, fire officials said.
The other businesses destroyed were Ora Catering and Village Laundry.
Rouvain Bension, owner of Ora, said he was sorry for the loss of property but relieved there was no loss of life.
“A, nobody was hurt; B, we have [insurance] coverage; and C, we don’t own the building,’’ Bension said. “When people don’t get hurt, you really have to count your blessings.’’
Bension said he expects to reopen his business elsewhere.
The owners of the other businesses and the building’s owner could not immediately be reached for comment.
Flames gutted the structure, which was encased in ice after water was poured on it for hours in frigid temperatures. The cold, along with high winds, hampered firefighters.
At one point before noon, crews scrambled to boost water pressure, one district chief said at the scene, sending pump trucks onto twisting side streets in search of hydrants.
Storm drains and gutters were overwhelmed by water runoff. A parking lot behind the burning structure was under nearly a foot of water, which threatened to overflow into the lobby of a nearby apartment complex.
The predawnfire sent clouds of noxious smoke over neighboring streets, rousing many people from their homes.
Bianca Germain, 23, lives only about 100 yards from the fire, and turned out briefly to watch the fire crews.
“I kept thinking that it was from inside our place,’’ Germain said.
“But I looked out the window and I saw the whole street was smoke.’’
“I’ve lived here for 50 years,’’ said John Madden, 69, of nearby Chiswick Road, standing in an overcoat and pajama pants. “A couple of the old-timers are going to miss [the pizza] place.’’
Travis Andersen and Martine Finucane of the Globe staff contributed to this report. Matt Byrne can be reached at email@example.com.