The deadly fire snarled traffic in Boston's densely populated Back Bay neighborhood. Boston EMS spokesman Nick Martin said 18 people, all police officers or firefighters, were taken to hospitals. Fire department spokesman Steve MacDonald said there were no reports of residents missing and it appeared everyone who was inside at the time had escaped.
City Councilor Josh Zakim, who represents the area, confirmed the two firefighters' deaths. He said nine units in the four-story building were affected.
"On this tragic day, our thoughts and prayers are with the brave men and women who fought this fire," Zakim said.
Major thoroughfare Storrow Drive was shut down for a time, and people were being asked to stay out of the area. The mayor's office designated the nearby Boston Public Library as a center for people displaced or otherwise affected by the fire to get help.
An assistant district attorney was sent to the scene, standard procedure in cases in which there are serious or potentially life-threatening injuries or deaths, said Jake Wark, a spokesman for Suffolk District Attorney Dan Conley. There was no immediate word on the cause of the fire, which was still burning several hours later.
Despite strong winds and cold temperatures, people gathered to watch firefighters work from outside the building.
"The smoke was unbelievable," said Kayla Dasilva, who lives a few blocks away and went with her roommate to see what was happening.
Anna Kosmidou, who lives in the apartment building next to the one that caught fire, said she and other residents were told they could not stay there Wednesday night.
"I'm very, very afraid. I'm still in shock," she said. "They called me at work, and then I ran over here."