CHELSEA (CBS) – At least four firefighters were injured battling a blaze on Bellingham Street in Chelsea.

The four-alarm fire broke out at a triple-decker apartment building at about 3:30 p.m. Monday afternoon.

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WBZ-TV’s Julie Loncich says a Revere firefighter was conscious and on a stretcher. He appeared to have suffered an injury to his face.

Fire officials say the four firefighters are being treated for non-life threatening injuries.

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Everyone who lives in the building was able to get out safely. Heavy smoke and flames were coming from the rear of the three story building and one resident said the fire was “out of control.”

It took crews about two hours to get the fire contained.

Nine adults and three children have been displaced.

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It is unclear how the fire started.