Beginning in 1952 at Rocky Flats northwest of Denver, we plunged into the Cold War producing plutonium triggers. Contractors working for what would become the Department of Energy secretly contaminated soils, waters and air during a lethal legacy creating 70,000 bombs. Now the site is a 5,257-acre wildlife refuge with hiking trails. Is it safe?
Some of the original acreage is closed to public access. Radioactive plutonium has a half-life of 24,000 years yet the 6,551 acres of Rocky Flats, once a Super-Fund Cleanup site, is coveted land with expansive views of the Flat Irons near Boulder. Modern real estate developments crowd the refuge to the south and east with condominiums, town homes, single family houses and shopping malls.
Are we suffering from atomic amnesia? In High Country News, Hannah Nordhaus wrote about the dangers of radiation from loose particles of plutonium, but “The half life of memory, by contrast is a much briefer thing. The contamination at Rocky Flats will long outlive our efforts to control or even remember it,” she wrote.
The Colorado Sun published Michael Booth’s article “Open space vs. safety: The debate goes nuclear at eager-to-please Rocky Flats.” Booth focused on the goal of an 80-mile bike path from Denver to Rocky Mountain National Park. Such a path would cross several counties. County administrators and county commissioners have mixed feelings about potential citizen exposure to radioactive particles.
Rocky Flats once had “hot rabbits” hopping in and out of prairie grasses. The bunnies had high doses of radioactivity absorbed from eating plants grown in poisoned soils. The site had 400 structures and buildings now demolished and infamous production rooms such as Room 3549 in Building 371 so heavily contaminated that radiation levels could not be measured. Standard detection equipment needles went off scale toward infinity hence the name “infinity rooms.”
Because of my interest in Colorado’s publicly accessible federal land, I had to visit the wildlife refuge, although I did so with trepidation. Libby Schultz, a Broomfield resident of four decades, would be my guide. She had friends and neighbors who had worked at Rocky Flats, including a man who in his 30s became sick with Mesothelioma cancer. As with other Rocky Flats workers, exposure to radiation would result in cancer years later. Schultz had another friend who worked on the Rocky Flats hazardous materials team. Accidents happened and everyone’s fear was of the blue flash of a “criticality,” or a nuclear chain reaction from a dangerous plutonium fire.
For decades, Cold War secrecy prevailed. Workers took their jobs seriously as part of defending America against the Soviet Union and communist aggression. In 1952, there were no interstate highways, no expanding suburbs, no daily traffic jams on Highway 93 between Denver and Boulder. Politicians welcomed the jobs and the federal paychecks that grew to $500 million annually and 8,000 employees at Rocky Flats. In the 1950s and 1960s, few workers questioned scientific or federal authority.
Employees dressed in protective gear, stood together in a stainless-steel assembly line, placing their arms into lead-lined “glove boxes” to piece together the parts of plutonium triggers or bombs in the Building 771 complex known as the Hell Hole. It took skill, nerves and patience to work the line, delicately holding spheres of plutonium-239 shaped like large oranges. These were fissionable cores, atomic bombs in their own right. Employees got sick, made mistakes, and human error in a bomb factory can have deadly consequences.
“The lungs are especially vulnerable,” writes Kristen Iverson in her evocative memoir “Full Body Burden: Growing Up in the Nuclear Shadow of Rocky Flats.” “Plutonium can ignite spontaneously when exposed to air, and as it burns, it turns into a very fine dust, similar to rust.”
Inhaling that dust can result in berylliosis, which is an inoperable lung disease causing victims to have less and less ability to breathe, having to pause going up or down as few as three stairs.
A dangerous fire broke out Sept. 11, 1957, with a radioactive plume that covered Golden, Arvada, Wheat Ridge and part of Denver. In Building 771, “For thirteen hours, unfiltered radioactive smoke poured out of the 771 smokestack – smoke filled with plutonium, americium, beryllium, acids, cleaning solvents, and other toxic contaminants,” Iverson writes.
In 1969, as the environmental movement accelerated, so, too, did a second fire at the Rocky Flats Nuclear Weapons Plant. It was Mother’s Day. The plant was understaffed. The maze of buildings contained plutonium equivalent to hundreds of thermonuclear bombs. A fire slowly spread through the glove boxes in Building 776 and Building 777. Air circulating in the production rooms helped grow the fire, but in a stroke of luck, a firefighter accidentally backed his truck into an electric pole, which cut off power and slowed the catastrophe. Two firefighters suffered radioactive exposure. They were hot or “crapped up.” The fire burned for six hours.
Protests began over the threat of nuclear war and proximity of the Rocky Flats weapons facility to Denver’s suburbs. Fear grew with stories in the Rocky Mountain News and Denver Post, which described Rocky Flats as “Denver’s Nuclear Neighbor.” Whistleblowers leaked stories of the plant’s own leakage of hazardous waste, sloppy cleanups and dangerous practices such as taking radioactive sludge from drying ponds and placing it in concrete for shipment elsewhere. Called “pondcrete,” the blocks contained both radioactive waste and hazardous chemicals, which often failed to solidify, spilled from boxes and required years to reprocess.
Two decades after the Mother’s Day fire, an unprecedented FBI investigation in June 1989 of the Department of Energy and its contractor Rockwell International revealed even more shoddy workmanship and dangerous exposure especially on 178 contaminated acres. A grand jury sifted through 760 boxes of documents and testimony from 110 witnesses. The jury members concluded that criminal prosecution of employees at both the Department of Energy and Rockwell International had been woefully inadequate. Justice failed as did attempts to provide medical compensation for suffering Rocky Flats workers and retirees.
As the Cold War wound down with the fall of the Berlin Wall, Rocky Flats moved from weapons production towards a massive environmental cleanup. A 1995 D.O.E study estimated cleanup would require 50 years and $36.6 billion, yet the Rocky Flats National Wildlife Refuge opened for public access Sept. 15, 2018.
Schultz and I went to the refuge’s main trailhead. No interpretive signs greeted us telling the story of weapons production. We were alone on the trail and heard a bird or two, but we did not see the 239 species of wildlife that live there. We arrived in the still morning air to avoid afternoon winds and dangerous dust. She has been to Hiroshima, and she wore a shirt featuring colored folded paper cranes that represent prayers for those who have died from nuclear radiation.
The only historical interpretation of the site is on private property south of Rocky Flats where artist Jeff Gipe’s horse statue wears a protective hazmat suit. Titled “Cold War Horse” the equine is posed with one raised hoof. Plaques discuss Hiroshima, Nagasaki and Rocky Flats, which is a mile away. Lettering states, “Let us recognize this part of our history and acknowledge the responsibility that comes with building weapons that have the potential to end human life on earth.”
Signs honor “the workers who suffered so much,” and who have “yet to be acknowledged by state and local governments.” A stone memorial was dedicated Oct. 18, 2015, after “the cleanup,” and it stands “as a reminder of a history that we must not forget.”
Within a few miles, residential and commercial neighborhoods thrive oblivious to the plutonium past. Thanks to the Rocky Mountain Peace and Justice Center, and Physicians for Social Responsibility Colorado, new trail signs have gone up warning of potential exposure to radioactive materials. The signs have been approved by Boulder County Open Space and the city of Westminster and are posted at trail entrances to the federal wildlife refuge. But 3 million Denver area residents longing for green space may continue to hike and bike the trails anyway.
Andrew Gulliford is an award-winning author and editor and a professor of history at Fort Lewis College. He can be reached at gulliford_a@fortlewis.edu.


