The Boston Fire Department reports firefighters responded to 95 Washington St., just off Commonwealth Avenue, for what turned into a three-alarm fire around 4 a.m.
Heavy smoke spread through the fourth, fifth and sixth floors and residents on those floors were evacuated. Residents on the lower floors were told to shelter in place.
The department says one resident was taken to a local hospital.
Between 30 and 40 residents were displaced, the department says.