It was around 5:30 a.m. when authorities were called to the unit block of N Franklin Street for the report of a possible carbon monoxide leak.
The five residents of the building were evacuated. Two occupants were able to drive themselves to a nearby hospital to be checked out.
Fire department and PECO crews responded to the scene to try and locate the source of the leak.
Officials say the building was being renovated, though there is no word on if that contributed to the leak.