Upon arrival, crews encountered heavy fire conditions above the third-floor ceilings in the area known as a cockloft. This open, horizontal space allowed fire to travel the entire underside of the roof from 1137 to 1147 Broadway.

Five aerial ladders were extended to the roof to allow firefighter access to ventilate smoke and open holes in the roof to expose and extinguish spreading flames. Five Alarms were needed to bring the fire under control, bringing assistance from Arlington, Boston, Brookline, Belmont, Cambridge, Chelsea, Everett, Malden, Medford, Revere, and Watertown. The Medford Fire Department also provided a drone, which allowed command staff to have a clear view of the roof operations and aided in keeping firefighters safe. Boston Sparks Association, Cataldo Ambulance, and the Salvation Army provided rehab for firefighters at the scene.

All occupants were able to evacuate the building safely. Several firefighters received minor injuries. At least two cats were located and removed to safety. The third floor and roof sustained heavy fire, smoke, and water damage, and the lower floors sustained extensive water damage. A total of 43 residents have been displaced and are being assisted. The cause of the fire remains under investigation.