At 0127 hours (1:27 am), Station 5, along with Station 4 (Malvern), Station 3 (Paoli), and Station 2 (Berwyn) for the Rapid Intervention Team (RIT) assignment were alerted to the 400 block of Lapp Rd in the Great Valley Corporate Center in East Whiteland Township for a reported building fire.

Initial reports indicated that there was some type of explosion in the building with a smoke condition. Supplemental information also indicated that the sprinkler system had activated.

Engine 5-2 responded along with Deputy Chief 5 (C. Strauss). Deputy 5 arrived on location and initially reported nothing showing from the exterior of a large one story commercial building. Upon gaining entry to the building, firefighters encountered a smoke condition with an activated sprinkler system. With this, Deputy 5 established "Lapp Road Command."

Interior crews discovered that an explosion occurred in the electrical room, resulting in significant damage to the walls and ceiling. The explosion sparked a fire, however, the fire was contained and knocked down by the sprinkler system.

Truck company crews from Ladder 4 and Tower 3 checked the roof for extension, and determined the fire had not spread to the roof line.

PECO was called to the scene due to electrical issues inside the building, and crews from all 4 Mainiline companies helped ventilate the building of smoke.

The East Whiteland Township Fire Marshal is investigating the cause of the fire.

East Whiteland crews finally cleared around 0345 hours (3:45 am)