built a VX facility at the site in 1959 when it was known as the Newport Chemical Plant. In 1964, the Wabash River Ordnance Works and the Newport Army Chemical Plant were effectively combined and renamed the Newport Army Ammunition Plant. Beginning in 1961, Newport became a site for chemical weapons manufacturing, producing the entire U.S. stockpile of VX nerve agent at the time. It was also used to store and eventually neutralize of the agent when the U.S. chemical weapons program was shut down. The stored VX amounted to 4.1% of the U.S. stockpile of chemical weapons in 1997 when the Chemical Weapons Convention came into effect. Chemical weapons disposal The U.S. Army Chemical Materials Agency designed the Newport Chemical Agent Disposal Facility (NECDF) for the sole purpose of destroying the VX chemical agent stored at the Newport Chemical Depot. Construction of the NECDF was completed in June 2003. The Army began VX agent destruction operations in May 2005, and completed operations in August 2008. Destruction was performed on behalf of the U.S. Army Chemical Materials Agency by Parsons Infrastructure & Technology, Inc. and more than 500 civilian employees worked at the facility. NECDF's permit was officially closed in January 2010. The site was the largest employer in Vermillion County between 1941 and its closing, having employed 1,000 workers at its peak. Process The Army employed neutralization for the destruction of the VX chemical agent. The agent was neutralized in steel reactors by thoroughly mixing it with heated sodium hydroxide and water. Control room operators directed and monitored the entire process remotely, using a state-of-the-art control system. Once agent neutralization was verified at the on-site laboratory, the caustic wastewater was placed into on-site intermodal storage containers awaiting transport for final treatment to Veolia Environmental Services in Port Arthur, Texas. This process is a different method than incineration which has been the primary manner of chemical agent destruction at other installations. Delays The start of operations was delayed several years due to problems in the arrangements of the disposal of the wastewater, which was anticipated to contains trace amounts of VX and 4 byproducts (less than 20 parts per million), problems that had not been completely solved at the start of destruction. Permafix and DuPont did not accept the wastewater for treatment, so it was stored on-site until the Army found another disposal option. Waste was eventually shipped to Port