The Umatilla Chemical Depot was one of nine U.S. Army installations in the United States that stored chemical weapons. The depot held about 12 percent of the nation's original chemical weapons.
Chemical weapons originally stored at the depot consisted of various munitions, such as rockets, and bulk containers loaded with GB or VX nerve agents or HD blister agent (mustard gas).
Although chemical weapon storage began in 1962, the history of the depot stretches back to 1941 when the facility was opened to store and maintain a variety of military items ranging from blankets to ammunition.
Between 1990 and 1994, the facility was reorganized to prepare for eventual closure. This included shipping all conventional ammunition and supplies to other installations.
Construction of the Umatilla Chemical Agent Disposal Facility, which used high-temperature incineration technology, was completed in 2001. Destruction of the depot's stockpile in September 2004 after testing of the incineration plant was complete.
The facility incinerated 220,604 munitions and containers holding 3,717 tons of GB, HD and VX. Operations were concluded in October 2011.
Source: U.S. Army Chemical Materials Agency