The 1945 Edgewood Arsenal explosion killed twelve munitions workers and injured more than fifty on May 25, 1945. Building 509 at Edgewood Arsenal in Harford County, Maryland was a production facility for the assembly of phosphorus igniter assemblies for incendiary bombs, employing a female staff of about 135 assemblers. Nine workers, of whom eight were African-American, were killed in the initial blast, and three more died of their injuries.^[1][2][3]