FRANKLIN COUNTY, Pa. Crews are at the scene of an explosion at Letterkenny Army Depot.
According to emergency dispatch, an explosion occurred at the depot located at 300 California Avenue, Chambersburg, CA.  Several people were reportedly injured in the incident and these people were taken to medical facilities
Franklin Fire Company wrote on their Facebook page that three people were injured by the blast and needed medical air transport:
The number or severity of these injuries is unknown at this time
The Army Depot has posted these messages Published on Their Facebook Page:
According to their Wikiepedia entry, Letterkenny Army Depot under the command structure of US Army Aviation and Missile Command (AMCOM) and the facilities will be used to conduct maintenance, remodeling, storage and demilitarization tactical operations Rockets and ammunition used.  The Army Depot has unique tactical missile repair capabilities that repair a variety of DoD missile systems, including the MIM-104 PATRIOT rocket and its ground support and radar equipment.
The entry continues:
More Recently, Letterkenny expanded its product range to include the designation of the CITE for power generation for the Army, the overhaul of tactical wheeled vehicles (HMMWVs), material handling equipment (7.5 tonne cranes) and Mobile Kitchen Trailers
in 2007 During the Iraq conflict, Letterkenny, in partnership with BAE Systems, began construction of armored vehicles protected against mine guns (MRAP). In 2010, the Joint Depot Source for Repair (JDSOR) was named for the Department of Defense.
This is an evolving story. FOX43 has a crew en route to the scene and we will provide updates as they become available.