No one was seriously injured in the four-alarm blaze, although responders said a firefighter was hospitalized.
A resident also apparently slipped and fell while fleeing the flames, which broke out late Monday in the basement and quickly raced through a street-level cellular phone store and two floors of apartments above.
The Red Cross was tending to what it said were 20 residents left homeless by the fire, which continued burning toward daybreak.
Main Street was temporarily closed between Smith and Market streets.
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