The Edgewood Chemical Activity (abbreviated ECA) was a U.S. Army site located in Edgewood, Maryland that stored chemical weapons. Its construction was started by Ordnance Corps in November 1917 and completed in less than a year. The arsenal was to employ about 10,000 civilian and military personnel in fabrication of chemical weapons and filling gas shells with phosgene, chlorpicrin, chlorine and mustard gas.[1] Since 1941, the U.S. Army stored approximately five percent of the nation's original chemical agent in steel ton containers, at the Edgewood Area of Aberdeen Proving Ground.