The six-alarm blaze engulfed a former furniture factory in the 300 block of North Front Street on June 24.
Chopper 6 video showed flames engulfing the entire structure as the fire rapidly intensified.
Crews battle massive fire in Allentown Pa.
The fast-moving fire damaged multiple properties and vehicles.
Six of those homes were destroyed and deemed uninhabitable, while two others sustained damage. Seven families were displaced.
The Lehigh County district attorney says the teen admitted to starting the blaze and "causing a catastrophe."
Chopper 6 over remains of building after massive 6-alarm blaze in Allentown
Neighbors described the fire as something out of a movie.
Another teenager is also facing charges for the fire.
"It's terrible," neighbor Ben Pope told Action News. "Never seen anything like this." After learning of the arrests, he added, "It's sad. They just ruined the rest of their lives- all for nothing. Affected all of these other people."
"It's just crazy that any kids did that," added fellow neighbor Robert Velez.
Drone video shows massive flames as a commercial building burned in Allentown
One firefighter suffered a minor injury while battling the blaze. No other injuries were reported.
The building was the former American Atelier furniture factory, which has since relocated.
Action News has learned that a developer had received approval last year to demolish the property and construct a 16-story mixed-use building with apartments and retail space. It is unclear how the fire may impact those plans.