Umatilla Ordnance Depot

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Umatilla Ordnance Depot (1941-2011) - A World War II Ordnance Depot was established in 1941 near Hermiston, Umatilla County, Oregon. The Umatilla Ordnance Depot mission changed in 1962 and the name was changed to Umatilla Chemical Depot to reflect the new mission. Closed by the Army in 2011 but 7500 acres were transferred to the Oregon Army National Guard (ORARNG) in 2016 as Camp Umatilla.

Igloo Blocks 2-5 at the Umatilla Ordnance Depot.

Umatilla Ordnance depot

The U.S. Army's decision to locate this Ordnance Depot in northeastern Oregon came because the area had a low population and lots of undeveloped lands. The 17,000-plus acres site was located along the Columbia River, along east-west railroad tracks and a major highway system.

J. A. Terteling & Sons of Boise, Idaho obtained the prime construction contract in January 1941 and construction began that month. At the peak of the 35 million dollar construction project over 7,000 people were employed. The project involved the construction of 1001 munitions storage igloos. The ends and sides of each igloo were ten inches of reinforced concrete, covered with two feet of dirt. There were two sizes of igloos, one 30 by 80 feet, and the other 24 by 61 feet. The igloos were designed to avoid catastrophic explosions of multiple igloos if one of them were to suffer an explosive accident. The igloos were designed to direct the force of an internal explosion upward not out so as to protect surrounding igloos. Staggered igloo placement added to the protection. The validity of these protections was tested on 21 Mar 1944 when 264 five-hundred-pound bombs exploded in an igloo. Six civilian workers died in the blast but none of the adjacent igloos were damaged.

One of the igloos at the Umatilla Ordnance Depot under construction.

Umatilla Chemical Depot

Umatilla Chemical Depot Safety Zones

In 1962 the Depot was assigned a new mission, receiving and storing chemical munitions, and a new name the Umatilla Chemical Depot. The Depot received and stored various military chemical munitions between 1962 and 1969

Umatilla Chemical Agent Disposal Facility

A Chemical Agent Disposal Facility was constructed between 1997 and 2001 at the Depot to safely deactivated and dispose of all of the stored chemical agents. In September 2004 Demilitarization operations began with chemical munitions transported from storage igloos to the demilitarization plant in Enhanced On-Site Containers (EONCS). The EONCS were resistant to fire, impact, puncture, or crushing, and 7,534 EONCS were delivered without incident.

Chemical Agent Disposal
Type Numbers Agent Tons
GB nerve agent 155,543 munitions 1,014
VX nerve agent 62,426 munitions 354
HD blister agent 2,635 ton containers 2339

In October 2011 the demilitarization operations ended and on 17 Jul 2012, the U.S. Army held a deactivation ceremony at the depot.

Camp Umatilla

The Depot was closed by the Army in 2011 and complex disposition activities began, in 2016, 7,500 acres were transferred to the Oregon Army National Guard (ORARNG) as Camp Umatilla. The transferred acreage included the Depot cantonment area as well as a number of the ordnance storage igloos. Within the cantonment, a historic district has now been established, spanning about 15 acres and encompassing 12 buildings that will be managed as historic—but all other structures are free to be used or demolished as Camp Umatilla requires. Six igloos will be maintained as historic, but others are now being demolished so that ranges and other resources can be constructed.

Camp Umatilla received approval for the construction of a $15.7 million barracks building in the National Defense Authorization Act passed by Congress on 1 Jan 2021. The project is in addition to an $11.3 million barrack building already under design. Together the buildings will add 448 beds. Other projects at the depot include a new schoolhouse and classrooms for the Guard’s Regional Training Institute, a new wastewater treatment facility and water distribution system, electrical work, fiber internet installation, fencing, demolition of more than 100 structures deemed unsafe or outdated, and refurbishment of other old buildings.

Current Status

Location:Near Hermiston, Umatilla County, Oregon.

Maps & Images

Lat: 45.807884 Long: -119.421002

  • Multi Maps from ACME
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  • Elevation: 583'

GPS Locations:

See Also:



Fortification ID:

  • OR0119 - Umatilla Ordnance Depot
  • OR0210 - Umatilla Chemical Depot
  • OR0211 - Camp Umatilla

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