Updated, 10 a.m.
A fire reported at 4:29 a.m. at 327-333 Summer St. went to 8 alarms. Firefighters found heavy fire on several floors of the five-story brick building; they were ordered to evacuate around 5:05 a.m., the Boston Fire Department reports.
The five-story former warehouse, the upper floors of which were being converted from artists' studios into office space, brought firefighters and trucks from across the city to combat the flames that at times were blowing out windows.
Fire officials estimate damage at $2 million. Investigators have been unable to get inside the building to try to determine a cause yet. Firefighters have set up a "collapse zone;" Summer Street could be shut the rest of the day.
BFD reports no injuries.