The seemingly endless mounds that dot the land on the former Umatilla Army Depot — storage bunkers called igloos that were built in the shadow of World War II — give an inkling of the complex 82-year history of the property that is now back in public control.

In 1940 the U.S. Army identified about 20,000 desolate acres covering 24 square miles of shrub-steppe land straddling Umatilla and Morrow counties in northeast Oregon as an ideal site for a military munitions and supply depot.

The land was remote; Hermiston is 10 miles away and at the time was home to less than 1,000 residents, now it’s about 20,000. The arid desert land, with an annual rainfall of about 10 inches, was perfect for storing explosives (and later chemical munitions).

Construction of warehouses, shops, offices, a fire station and railroad engine house, along with a web of roads and railroad tracks, began in 1941. In a little less than a year the team of 7,000 construction workers also built 1,001 igloos in two sizes, 30 by 80 feet and 24 by 61. The igloos form large bumps across the landscape and are still clearly visible from Interstate 84 to the south of the depot and Interstate 82 along the eastern border.

A home for bombs and bullets

The Umatilla Ordnance Depot opened on Oct. 14, 1941, and 13 days later the first shipment of 20,000 bombs arrived. Five weeks after that Japan attacked Pearl Harbor and about 2,000 depot employees went on round-the-clock shifts to receive and ship munitions, and care for the stored items, in support of the war effort.

Like many industries and facilities supporting the war, the depot relied heavily on civilian women ordnance workers, who made up 27 percent of the workforce and did everything from driving trucks and forklifts to handling munitions.

At the height of the war, the depot experienced a deadly tragedy when six workers, five men and a 20-year-old woman, were killed by a massive explosion while moving 500-pound bombs into an igloo on March 21, 1944. The blast rattled windows in Hermiston and left a giant crater where the igloo had been. Linda Gilleese told the Hermiston Herald in 2008 that the front axle of one of two vehicles destroyed in the blast landed 20 feet from her desk at her depot office nearly a mile away.

Thankfully, the igloo’s design — walls constructed of 10 inches of reinforced concrete with a thin concrete ceiling covered by two feet of dirt — worked as designed, allowing the blast to go up rather than out. None of the surrounding igloos ignited or were damaged.

The largest remaining piece of concrete from the obliterated igloo was placed in front of the Army administration building, now occupied by the Oregon National Guard, along with a memorial plaque honoring those who died. The precise cause of the explosion was never determined. The event marked the only fatal injuries suffered during 70 years of storing conventional and chemical munitions at the depot.

The depot went on to provide conventional munitions for U.S. forces during the Korean War — as many as 1,500 workers handled nearly 34 tons of ammunition and other military supplies each month — as well as Vietnam and Desert Storm in 1991, also known as the Gulf War.

Conventional to chemical

The depot’s focus began to shift in 1962, along with a name change to the Umatilla Army Depot, when it began to store chemical munitions, which kept arriving until 1969. The depot ended up storing 12 percent of the country’s chemical munitions stockpile.

Jerry Lanphear, a longtime federal employee of the Army who spent decades at the depot, recalled during a 2012 interview on the eve of his retirement that the entire depot was bustling during the 1960s. “Every building, every area was busy,” said the former guard who worked his way up to director of depot security.

All the igloos were full of bullets, bombs or chemical munitions. On some occasions, bombs were stacked outside between the berms separating igloos that were already full. Lanphear noted that ton containers holding mustard blister agent were initially stored outside.

The shift from traditional explosives to chemical munitions was complete by 1994 when the last conventional ammunition and supplies were sent to other Army depots around the country. The facility changed its name, again, in 1996 to Umatilla Chemical Depot.

About the same time the U.S. Congress ratified the country’s inclusion in the International Chemical Weapons Convention, along with more than 180 other nations that agreed not to produce chemical weapons and to destroy existing stockpiles. The move dovetailed with the Army’s intention to eventually close the depot.

Construction of the massive Umatilla Chemical Agent Disposal Facility at the depot commenced in 1997 and was completed in 2001.

That was the easy part. Oregon’s stringent environmental laws nearly thwarted the project, but state regulators and the Army ultimately reached agreement on environmental and safety expectations for the process.

At long last, incineration of Umatilla’s chemical stockpile of more than 220,000 munitions and 3,720 tons of chemical agent commenced Sept. 8, 2004, when workers began to feed rockets filled with sarin — one of the most toxic and rapidly acting nerve agents — into one of the plant’s two giant furnaces heated to more than 1,000 degrees Fahrenheit.

Over the next seven years the plant incinerated more rockets along with projectiles, bombs, landmines and spray tanks that contained sarin or VX, another deadly nerve agent, and ton containers filled with mustard blister agent. The last item went through the furnace on Oct. 25, 2011, ahead of the 2012 deadline set by the Chemical Weapons Convention.

“There’s nothing better in our professional lives than completing our mission safely and ahead of schedule,” said Steve Warren, project general manager for URS, the company that operated the disposal plant for the Army. “That’s exactly what Team Umatilla did.”

The Army demolished the incineration plant in about a year, completing the work in July 2014. Following a clean bill of health by Oregon’s Department of Environmental Quality for the former incineration site and all the igloos, the depot was ready for its return to local control.

What’s next?

After the Army added the depot to the federal Base Realignment and Closure list in 1988, depot and local officials began contemplating how the land could be used to benefit the region once the Army was done with the facility.

The Columbia Development Authority (CDA) was formed in 1995 to develop and implement a reuse plan. It’s composed of representatives of Umatilla and Morrow counties, the ports of Morrow and Umatilla, and the Confederated Tribes of the Umatilla Indian Reservation (CTUIR).

But first the Army needed to officially transfer the land.

The first step came in 2017 when the Army preserved the land’s military legacy by transferring 7,500 acres to the National Guard Bureau for a permanent large-scale training facility for the Oregon National Guard. The Guard is using the original Army headquarters area just inside the main gate off I-84 and the west half of the former depot land, except for the southwest corner, which is earmarked port industrial.

Last March the Army conveyed 9,500 acres of the former depot property to the CDA, which is intended to benefit local residents, municipalities and taxing districts. Greg Smith, executive director of the CDA, said 4,000 of those acres will soon be conveyed to the CTUIR for wildlife habitat preservation.

The Army’s transfer of 17,000 acres is a big deal for the region, Smith said, for the Army’s goal of returning abandoned military real estate to productive use for local communities. It’s the fourth largest transaction in the Army’s Base Realignment and Closure history and the largest in the past 20 years.

“The transfer represents what can be accomplished when partners come together for a mutually desired outcome,” Smith said. “It’s public land now, it belongs to everyone.”

He is confident the land designated for industrial use — which includes the area where the incineration facility was located and has usable warehouse space, office buildings and parking lots — will attract companies eager to benefit from land adjacent to two major freeways, Union Pacific’s main rail line and barge access via the Columbia River.

“It’s some of the most pristine industrial land available in the state and in a strategic location,” Smith said, noting the clean-up efforts have met all state and federal environmental requirements. It’s also generally flat with an arid desert climate and has substantial access to electrical power and natural gas capacities.

Interest is beginning to build, including from two energy companies focusing on solar power and renewable hydrogen generation. While such companies likely wouldn’t provide a big jump in employment, their projects would give a healthy tax revenue boost to support local services.

There are other possibilities, such as replacing the heavy steel doors on the igloos with roll-up doors and renting them out for storing vehicles or just about anything else. That’s been done at the former Army weapons storage depot in Colorado.

Local agricultural could be interested in some of the vacant land as well.

As for those igloo landmarks, most of those likely aren’t going anywhere. Smith said it would cost upwards of $40,000 to remove one igloo, which is pricey for the amount of land it would open up. So that unique element of the depot landscape will continue to be a reminder of an illustrious past.

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Hal McCune is a longtime Pendleton resident who worked as communications director at the chemical agent disposal facility from 2006-2014.