Arson caused upwards of $100,000 in property damages to the $216 million, 27-floor residence hall rising from Temple University on North Broad Street, federal officials said.
Bureau of Alcohol, Tobacco, Firearms, and Explosives officials said the agency is investigating five fires set at the construction site between Monday and Tuesday. The fires were lit on five different floors.
Three construction workers were treated and released from the hospital.
No other fires have been reported, and no suspects are in custody.