The fire broke out around 4:40 p.m. Wednesday at a home in Mount Oliver.
Allegheny County Fire Chief Matt Brown tells the Pittsburgh Post-Gazette first responders tried to rescue a boy that was trapped on the second floor but were unable. The child's name has not been released.
Multiple firefighters had to be treated at the scene for smoke inhalation.
Brown says the cause of the fire is still under investigation, but it does not appear to be suspicious.
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