A big-game hunting season is underway for the first time at Rocky Flats National Wildlife Refuge, which surrounds a former nuclear weapons plant.
The U.S. Fish and Wildlife Service, which manages the refuge on the outskirts of Denver, opened a pilot elk hunt in September as part of a Trump administration push to expand hunting and fishing on public lands.
The agency says elk numbers have more than doubled since 2019, exceeding the capacity of the landscape, threatening rare plants and risking the spread of disease among the clustered animals.
But the property welcoming hunters has a contentious history. During the Cold War, the site held a plant making plutonium triggers for nuclear weapons. The plant closed in 1989, and the government completed a roughly $7 billion cleanup in 2005. The site officially opened to the public as a wildlife refuge in 2018.
Some environmental and public health advocates remain skeptical of the cleanup and are concerned that remaining radioactive materials in the soil pose a danger.
“We believe there is abundant evidence for why that site still poses a risk to human health,” said Chris Allred with the Rocky Mountain Peace and Justice Center, which has advocated to close the refuge over safety concerns.
He pointed to a 2024 sampling effort by non-government scientists that detected plutonium in air filters collected near Rocky Flats during high winds.
David Havlick, a professor of geography and environmental studies at the University of Colorado in Colorado Springs, said opening the site to hunting risks obscuring its history.
“I think it's important we don't lose sight of what happened there and why it is the kind of place that it is,” he said.
Federal and state agencies say extensive air and soil monitoring shows that contamination at the refuge meets standards and that the site is safe for visitors and wildlife. Most soil samples collected in a 2020 assessment were below background levels. Additionally, the inner core of the refuge, where the former plant stood, remains closed to the public.
“If you visited the refuge hundreds of times in a year, your dose still would be much less than a medical X-ray,” reads a sign at the refuge entrance.
The Fish and Wildlife Service has contemplated hunting at Rocky Flats since before the refuge was established and says there are no restrictions to eating elk harvested there. Its August 2026 hunt plan cited a 2005 study that found some radioactive contaminants in deer tissue, but estimated minimal risk from eating deer meat.
“The results indicate no significant uptake of contaminants by deer or other wildlife species at the site,” the hunt plan summarized the study findings.
David Lucas, the refuge manager, also told a Boulder County board last year that elk had been tested in 2023.
“Obviously, we have thought about that,” he said. “The animals that we collected in 2023 were sampled for radionuclides, and all were ‘non-detect’ in all tissues.”
In the decades after the plant closed, nearby communities grew. The refuge’s grasslands remained largely undeveloped. The area is home to globally rare prairie plants and abundant wildlife, including falcons and coyotes.
Elk have multiplied, too. After the Marshall Fire in 2021, even more congregated there. Now, the population in the refuge totals about 700. The U.S. Fish and Wildlife Service says the elk are exerting pressure on other wildlife and their congregation risks the spread of diseases like chronic wasting disease, which has been detected at the refuge. USFWS wants to bring numbers down to around 200 to 250 elk.
The refuge’s new elk hunt began this fall, including an archery season that ran from Sept. 17 to Sept. 28 and a firearm season from Oct. 1 to Dec. 14. Hunters were required to get a Colorado Parks and Wildlife tag through a lottery and attend a mandatory orientation. The refuge prohibits center-fire rifles, handguns, lead ammunition and hunting dogs.
This story was produced by the Mountain West News Bureau, a collaboration between Boise State Public Radio, Wyoming Public Media, Nevada Public Radio, KUNR in Nevada, KUNC in Northern Colorado, KANW in New Mexico, Colorado Public Radio and KJZZ in Arizona as well as NPR, with support from affiliate newsrooms across the region. Funding for the Mountain West News Bureau is provided in part by the Corporation for Public Broadcasting and Eric and Wendy Schmidt.
