Chopper 6 flew as over the scene shortly after noon in the 700 block of East 14th Street.
Action News learned that pepper spray somehow spread through three residence halls around 11:30 a.m.
More than 50 students in Hanna, Thayer and Grasselli Halls were evacuated. At least 5 were sickened by the fumes.
Firefighters worked to air out the buildings, then all students were allowed back in.
Investigators say the pepper spray was accidentally released in Hannah Hall.
Click here to get the latest Philadelphia news and headlines from across the Delaware and Lehigh valleys.