Umatilla Army Depot

The Umatilla Chemical Depot, based in Umatilla, Oregon, was a U.S. Army installations in the United States that stored chemical weapons.

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The Umatilla Chemical Depot (UMCD) was one of nine Army installations in the United States that stored chemical weapons. The chemical weapons originally stored at the depot consisted of various munitions and ton containers containing GB or VX nerve agents or HD blister agent. Stockpile disposal operations were successfully concluded in October 2011 using high-temperature incineration technology. This technology has been used by the Army for more than two decades, safely at several sites to successfully dispose of more than 80 percent of the nation’s original chemical weapons.

The Army worked in partnership with Oregon state and local government agencies, as well as federal agencies like the U.S. Environmental Protection Agency and the Centers for Disease Control and Prevention, to safeguard the local community and protect the environment as we stored and disposed of these chemical weapons. The Army safely stored approximately 12 percent of the nation’s original chemical weapons at the Umatilla Chemical Depot starting in 1962.

The UMCD opened in 1941. The Umatilla Chemical Depot began receiving and storing chemicals munitions between 1962 and 1969. The chemical warfare agents VX and GB (nerve agents) and HD (blister or “mustard” agent) were stored as liquid in various types of munitions and containers, including rockets, bombs, projectiles, mines, bulk containers and aerial spray tanks. Chemical weapons stored at the Depot represented about 12 percent of the nation’s original chemical weapons stockpile.

The depot’s mission was to store and maintain a variety of military items, from blankets to ammunition. The depot’s mission, however, changed in 1962 to include the safe storage of chemical weapons. From 1990 to 1994 the facility reorganized in preparation for eventual closure, shipping all conventional ammunition and supplies to other installations.

The Umatilla Chemical Agent Disposal Facility (UMCDF) was designed for the sole purpose of destroying the chemical weapons stored at the UMCD. Facility construction was completed in 2001, and the Army began testing the facility. Weapons disposal took place from 2004-2011.

The Umatilla Army Depot (Lagoons) site occupies about 20,000 acres in Hermiston, Oregon and has operated as a storage depot for conventional munitions and chemical warfare agents since 1941. Areas of the site were contaminated with explosives and metals as a result of past demilitarization and disposal operations. Between the 1950s and 1965, about 85 million gallons of wastewater from explosive washout operations were discharged into two unlined lagoons. The lagoons cover about half an acre.