Following an extensive investigation by the Fort Wayne Fire Department (FWFD), the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF), insurance investigators for the National Magnesium & Aluminum Foundry, Inc., and, Barker & Herbert Analytical Laboratories, Inc., which supervised the testing of several items from inside the structure, the fire August 1, 2006, at National Magnesium & Aluminum Foundry, Inc., 4817 Industrial Road, is being ruled undetermined.

The initial fire was believed to have started in the back part of the structure.  The fire, through its progression, eventually reached a finishing oven and miscellaneous gas cylinders located in the general area causing an explosion.  Due to the extensive damage caused by the explosion, the exact point of origin and the initial cause of the fire remain unclear.