A grease fire at a fast food restaurant in Copley Square spread through the walls of a Back Bay building Tuesday morning, causing fire crews to rush to the scene in the middle of the morning rush hour.
Firefighters were called to the Burger King at 551 Boylston St. just before 7:30 a.m., the fire department said.
When crews arrived, there were flames coming from the four-story building.
The two-alarm blaze spread from the kitchen of the restaurant and into the duct work. It also spread into the walls, reaching the roof.
There were no reports of injuries. Fire officials estimated the damage at $100,000.
Follow Michael Naughton on Twitter @metrobosmike.