Bedford fire, and police responded to a call for fire alarms that were activated at 15 Iron Horse Drive, Unit B, on Sunday.
While en route, at about 4 p.m. responding units were advised callers could see smoke from outside the building, and smoke was filling the hallways.
Firefighters arrived and had smoke showing from some of the second-floor windows, and the sprinkler system activated in part of the building. Merrimack firefighters were also requested to respond with additional apparatus and other towns responded for station coverage.
Several people were evacuating the building on their own, and firefighters and police officers went from apartment to apartment, evacuating those occupants that had remained inside the building.
Firefighters made entry into a second-floor apartment that appeared to be the source of the smoke. They located a burning couch that the sprinkler system had mostly extinguished and a heavy smoke condition in the apartment and in the hallway.
Crews removed the couch and pushed it off the second-floor balcony, and opened windows to allow smoke to clear. Fans were used to eject smoke from the apartment and hallways.
A large group of residents watched from the parking lot as firefighters fought the fire, and water poured out of the building from the sprinkler system.
The fire appears to have been limited to a single apartment, but several apartments had water damage from the activated sprinkler system. Bedford fire said many people would be displaced from the large multi-unit apartment building.
The fire was brought under control within about 30 minutes, and it did not appear any occupants or firefighters were injured.
The fire will be investigated by the Bedford Fire Department.