A Poisoned Nuclear Site Now a Wildlife Refuge in Colorado

Elk Now Graze Where Bombs Were Made

Fifteen miles northwest of Denver, hikers walk trails through rolling tallgrass prairie with views of the Rocky Mountain Front Range.

Elk herds cross the path. Prairie dogs pop up from burrows. It looks like untouched wilderness, and in a way it is.

But beneath the surface lies a darker history.

From 1952 to 1989, this land housed a secret factory that made the plutonium cores for nearly every nuclear weapon in America’s arsenal.

Rocky Flats National Wildlife Refuge opened to the public in 2018, and what happened between bomb-making and bird-watching is one of the strangest transformations in American history.

239 Wildlife Species Live Here Now

The refuge is home to various animals, including a herd of 150 elk, occasional black bear, mountain lions, and moose, as well as badgers, bats, coyotes, two species of owl, mule deer, and porcupines.

The site also contains an estimated 630 species of plants, as well as the globally rare xeric tallgrass prairie.

The refuge provides habitat for the federally threatened Preble’s meadow jumping mouse and serves as a protected corridor for migrating wildlife.

The buffer zone that once kept civilians away from nuclear secrets accidentally preserved one of Colorado’s last stretches of native prairie.

The Plant Made 70,000 Nuclear Triggers

Rocky Flats produced plutonium bomb cores, about 70,000 in all, to enable the U.S. government to pursue nuclear deterrence during the Cold War.

For much of its operational lifetime, Rocky Flats was the sole mass producer of plutonium components for the United States’ nuclear stockpile.

Workers machined plutonium into hollow bomb cores about the size of misshapen grapefruits that weighed about six pounds each.

Officials called them “triggers,” but each one was itself a nuclear weapon comparable to the bomb dropped on Nagasaki.

Two Fires Spread Plutonium Across Denver

The contamination primarily resulted from two major plutonium fires in 1957 and 1969, since plutonium is pyrophoric and shavings can spontaneously combust.

The 1957 fire burned through the air filters that normally removed plutonium from the building’s exhaust, releasing radioactive material into the atmosphere.

The public was not informed of substantial contamination from the 1957 fire until after the 1969 blaze. Plutonium particles were found at an elementary school 12 miles away.

The FBI Raids a Fellow Federal Agency

On June 6, 1989, a convoy of about 30 vehicles carrying more than 70 armed FBI and EPA agents raided the Department of Energy’s plutonium-processing plant for suspected environmental crimes.

It was the first time U.S. government agencies raided another agency.

FBI agents pretended they were there for a safety briefing, then revealed the true reason to stunned officials as part of “Operation Desert Glow.”

Production stopped that December and never resumed.

Original Cleanup Estimate Was $36 Billion

The DOE initially estimated that cleanup of the site would take 70 years and cost $36. 6 billion.

In 1993, the DOE revealed that the site contained at least 14 tons of plutonium, 7 tons of enriched uranium, 281 tons of depleted uranium, 65 tons of beryllium, and large amounts of other toxic chemicals.

In 1995, the DOE contracted the Kaiser-Hill Company to undertake an accelerated cleanup at a cost of $7.3 billion.

The project aimed to finish in a decade instead of seven.

Workers Demolished 800 Buildings

Between 1992 and 2006, crews decommissioned and demolished more than 800 structures, removed 21 tons of weapons-grade material, and took out more than 1.3 million cubic meters of waste including contaminated soil.

They drained 30,000 liters of plutonium solutions, removed more than 1,450 contaminated glove boxes and 700 tanks, and performed cleanup actions at 130 sites.

Cleanup was declared complete on October 13, 2005.

The Central Core Stays Closed Forever

The refuge does not include the 600 acres that contain the former weapons site and monitoring areas, which remain under DOE jurisdiction and will not be opened to the public.

The DOE still maintains 1,300 acres as part of their legacy management for long-term care and maintenance, ensuring the cleanup functions as designed.

Workers continue monitoring groundwater, soil, and air at the sealed core. The buildings are gone, but what’s buried underneath stays put.

Rare Prairie Survived the Cold War

The refuge was created in part to preserve and protect more than 630 species of plants, as well as the globally rare xeric tallgrass prairie.

The security buffer that kept people away from the weapons plant for four decades also kept developers out.

Native Americans occupied the land intermittently before the 1800s.

Starting in 1868, the Scott family established a homestead, and later the Lindsay family raised cattle there until 1951.

The Lindsay Ranch barn still stands along one of the trails.

Some Say It’s Still Not Safe

In 2017, local activists sued the U.S. Fish and Wildlife Service to block the refuge from opening, but the district court dismissed the lawsuit.

In 2018, several Colorado school districts voted to ban students from attending school-sanctioned trips to the former Rocky Flats plant.

Biologist Harvey Nichols said the government’s sampling regime was unlikely to have identified hotspots in surface soils.

Critics argue that plutonium remains dangerous for 24,000 years and no amount of exposure is truly safe.

Federal Agencies Stand By the Cleanup

The EPA did extensive air and soil sampling on the refuge during the planning and cleanup, and test results confirmed the area could be safely used by the public without additional cleanup.

Based on the site’s cleanup standard, a refuge worker might face an increased cancer risk of 1 in 133,300, assuming they work eight hours a day, 250 days a year for nearly 19 years.

Federal signage notes that if you visited the refuge hundreds of times in a year, your dose would still be much less than a medical X-ray.

Bomb Factory to Bio Sanctuary

The U.S. Fish and Wildlife Service opened the refuge’s trails on September 15, 2018.

Visiting the refuge is free, and trails are open year-round to hiking, wildlife viewing, photography, bicycling, cross-country skiing, snowshoeing, and horseback riding.

The debate over safety continues, and probably will for decades. But for now, the elk don’t seem to mind.

They graze the same prairie where workers once shaped plutonium into bomb cores, crossing paths with hikers who may or may not know what lies beneath their feet.

Visiting Rocky Flats National Wildlife Refuge, Colorado

The refuge is free to visit and open year-round. There are 15 miles of moderate hiking trails through rolling prairie, with dirt and gravel surfaces.

Only service dogs are allowed, no swimming or wading in refuge lakes, and visitors must stay on trails. The main entrance has restrooms and parking.

The Lindsay Ranch Loop Trail features a historic barn and crosses Rock Creek. Bring sun protection since there’s no tree cover on most trails.

This article was created with AI assistance and human editing.

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