Once a massive and highly secretive facility nestled in Oak Ridge, Tennessee, K-25 — later renamed the Oak Ridge Gaseous Diffusion Plant — was a cornerstone of the Manhattan Project and a critical site for uranium enrichment during World War II. Constructed in the 1940s, this facility played a key role in the development of the first atomic bombs using gaseous diffusion technology. Though the plant was decommissioned decades later, its legacy endures as a powerful symbol of American scientific achievement and Cold War-era innovation.
Origins and Purpose
In the early 1940s, as part of the U.S. government’s efforts to develop nuclear weapons, the K-25 gaseous diffusion plant was established at the Clinton Engineer Works in Oak Ridge. K-25’s primary mission was to produce enriched uranium using the gaseous diffusion method — a process that involved passing uranium hexafluoride gas through barriers to separate the lighter uranium-235 isotope from the heavier uranium-238 isotope. This innovative method proved to be more efficient and cost-effective compared to other techniques employed during that era and ultimately provided the highly enriched uranium for the Hiroshima weapon, Little Boy.
A Monumental Structure
Upon its completion in 1944, the four-story K-25 facility was the largest building under one roof in the world, covering over 5 million square feet. The facility’s U-shaped design created room for thousands of on-site workers and housed the complex machinery necessary for uranium enrichment. At its peak, the site employed more than 25,000 individuals.
Those residing in communities such as Scarboro, Elza, Wheat, and Robertsville were relocated to make room for Oak Ridge’s wartime efforts. Due to its increasing workforce population, the town quickly grew to a population of more than 70,000 in less than two years, making it one of the largest towns in Tennessee at the time, despite not being listed on any public maps.
Post-War Expansion and Operations
After World War II, the K-25 plant continued its operations, contributing to the Cold War effort by producing enriched uranium for both defense and commercial purposes. The site provided fuel to the first nuclear submarine, the U.S.S. Nautilus, and the first nuclear power plant in Shippingport, Pennsylvania before eventually developing new methods of enrichment using centrifuge technology.
In 1955, the site was officially renamed the Oak Ridge Gaseous Diffusion Plant. Over the years, the site expanded and additional gaseous diffusion buildings — K-27, K-29, K-31, and K-33 — were constructed. By 1964, the K-25 building ceased operations, though other facilities remained active until 1985.
Environmental Cleanup and Redevelopment
Following the cessation of uranium enrichment activities, the K-25 site faced significant environmental challenges due to decades of industrial activity. In 1989, the Department of Energy (DOE) initiated a comprehensive cleanup effort, spearheaded by the newly formed Office of Environmental Management (EM). This extensive project involved the demolition and cleanup of more than 500 structures, including the five gaseous diffusion buildings, and more than 50,000 truckloads of soil. Demolition began in January 2006 with K-29 and was completed in February 2017 with K-27.
Today, the site has been transformed into the East Tennessee Technology Park, a multi-use industrial park that hosts various businesses, historic land preservation, and a recreation area. This redevelopment has spurred economic growth in the region, attracting investments and creating job opportunities.
Preserving History
Despite the physical demolition of the original K-25 building, efforts have been made to preserve its historical significance. Since its opening in 2020, the K-25 History Center has offered visitors a glimpse into the plant’s storied past and features exhibits, artifacts, and firsthand stories that chronicle the contributions of the workers, and the technological advancements achieved at the facility.
Honoring Workers
The legacy of the Oak Ridge Gaseous Diffusion Plant lives on through the thousands of men and women who worked there. These dedicated individuals played a vital role in shaping history, often under strict secrecy and difficult conditions. Today, many former workers are dealing with long-term health impacts as a direct result of their time at the site.
Giving Home Health Care is proud to help honor their service by assisting eligible former K-25 workers in accessing benefits from the Department of Labor, including no-cost home health care for the rest of their lives. Through the Energy Employees Occupational Illness Compensation Program (EEOICPA), we can help these individuals receive the financial compensation and personalized care they rightfully deserve. It’s our mission to care for those who supported our nation during one of its most pivotal moments in U.S. history — contact us today to learn more.