The fire broke out in the Roosevelt Building in the 600 block of Penn Avenue just after 10:30 p.m. on Sunday December 11, Pittsburgh Bureau of Fire, Pittsburgh Public Safety, and the Red Cross of Great PA said in separate statements.
One person was pronounced deceased at the scene, and their name has yet to be released.
Another person in the building was taken to an area hospital where they remain in serious condition, authorities explained in the releases. A medic with Pittsburgh EMS was also taken to a local hospital for treatment after smoke inhalation. And a firefighter was treated on-scene for minor injuries.
"Out of precaution, gas was shut off to the building as crews worked. The fire was declared under control at approximately 12:13 a.m.," Pittsburgh public safety officials said in the release.
There were 106 people who lived in the building who were assisted by the Red Cross's Disaster Action Team as they sought warmth and shelter.
The cause of the fire has not been determined. Detectives from the Fire Investigation Unit were on-scene and the investigation is ongoing.
Click here to follow Daily Voice Gettysburg and receive free news updates.