As mandated by Congress in 1986, destruction of the U.S. chemical weapons stockpile, which at one time comprised more than 30,000 tons of chemical warfare agents in explosively configured weapons and bulk containers, began in 1990 on Johnston Atoll in the Pacific. The U.S. Army went on to successfully complete destruction of weapons at six more sites across the continental U.S. by 2012 at installations in Alabama, Arkansas, Indiana, Maryland, Oregon and Utah.
While those stockpiles were under destruction, additional legislation required the Defense Department to assess and demonstrate alternative technologies to destroy chemical weapons by means other than incineration. Successful implementation of alternative technologies resulted in the safe destruction of the remaining chemical weapons stored at the U.S. Army Pueblo Chemical Depot in Colorado and at the Blue Grass Army Depot in Kentucky.
In addition, a team of companies in Colorado led by Bechtel National, Inc. completed the destruction of more than 780,000 mustard agent-filled projectiles at U.S. Army Pueblo Chemical Depot on June 22. Destruction operations in Pueblo began in March 2015, with more than 2,613 U.S. tons of chemical agents destroyed using a neutralization method followed by biotreatment and explosive destruction technologies.
The final munition was destroyed July 7 in Kentucky by a joint-venture team led by Bechtel National, Inc. and Parsons Corporation, using neutralization and explosive destruction technologies to eliminate more than 100,000 mustard agent and nerve agent-filled projectiles and nerve agent-filled rockets. Destruction operations at the Blue Grass Army Depot began in June 2019, with more than 523 U.S. tons of chemical agents safely destroyed.