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The past, present, and future of the Hanford Site is long and complex, dating back well before the site's construction in the 1940s and long into the future beyond today's cleanup efforts.
During the World War II and Cold War years, the site's focus was on plutonium production. Now, efforts are geared at cleanup of one of the most contaminated nuclear sites in the world.
Explore the story of Hanford below.
An overview of the Hanford Site's history, largely from the 1940s to the late 1980s.
The site today
The Tri-Party Agreement was signed in 1989 between Ecology, the U.S. Department of Energy, and the U.S. Environmental Protection Agency (EPA) and is a tool to guide cleanup. We work with the EPA to ensure Energy — Hanford's owner and manager — follows environmental laws and meets cleanup deadlines required in the Tri-Party Agreement.
We also communicate with the Nez Perce Tribe, Confederated Tribes of the Umatilla Indian Reservation, and the Confederated Tribes and Bands of the Yakama Nation to hear their perspectives and goals for Hanford cleanup.
Cleanup projects today are complex. While much has been achieved in 35-plus years of cleanup, many challenges remain. Our priority is to oversee cleanup of the Hanford Site and ensure the protection of the area's land, air, and water for current and future generations.
Highlighted below are just some of the site's most important facilities or cleanup projects and their current status. Is there a part of Hanford not described below you'd like to learn more about? Let us know.
Hanford's K-West Reactor, one of three reactors not yet cocooned, and the cocooned D Reactor.
Nine nuclear reactors were built on the Hanford Site during World War II and the Cold War to produce plutonium for the nation's nuclear weapons program.
The world's first full-scale plutonium production reactor, B Reactor, began operations in September 1944, follSo far, seven of Hanford's nine reactors have been placed in interim safe storage, also known as cocooning. Cocooning involves removing all of a reactor's supporting facilities that surround it and sealing it in a concrete and steel enclosure.
Each cocooned reactor is entered every five years for inspection to ensure nothing is getting in, and no contamination is getting out. The reactors will be cocooned for 75 years which allows radiation levels to naturally decay to a safer level for future dismantling and disposal.
The B, and K-West Reactors are the only ones to have not yet been cocooned. Cleanup is ongoing at the K-West reactor, and B Reactor has become a Manhattan Project National Historical Park location.
A look at the toxic, radioactive waste inside one of Hanford's 177 deteriorating underground storage tanks.
Today, there are 177 underground storage tanks on the Hanford Site, holding about 56 million gallons of highly radioactive and chemically hazardous waste – the byproduct of decades of plutonium production.
The tanks range in storage capacity from 55,000 gallons to more than one million. Of the 177 tanks, 149 are single-shell and 28 are double-shell.
All of the tanks are well past their design life, at least 67 are assumed to have leaked in the past, and three are currently leaking.
One of our top priorities is to ensure the safe handling and retrieval of Hanford tank waste and see that it's sent to the Waste Treatment Plant.
A look at Hanford's Pretreatment Facility, part of the Waste Treatment Plant.
Our agency oversees the permitting and operation of the Waste Treatment Plant, which is treating Hanford's underground tank waste.
The Low-Activity Waste Facility began operation in October 2025 and the High-Level Waste Facility is under construction. At the plant, tank waste is transformed into glass – a process called vitrification. The vitrified waste is poured into stainless steel containers. Vitrified low activity waste is disposed of onsite and high-level waste will be disposed offsite. While the treated waste will still be radioactive, it will be in a more stable form and will be more protective of the air, water, and soil.
Five massive facilities on the Hanford Site were responsible for removing plutonium from fuel rods during production years. These buildings remain highly contaminated today.
The "canyons," named for their hundreds of feet in length and dozens in height, include: B Plant, T Plant, U Plant, Plutonium Uranium Extraction Plant (PUREX), and Reduction-Oxidation Plant (REDOX).
Of the five, one of the most recognizable is PUREX. This canyon was built in the 1950s, began operations in 1956, and eventually shut down for good in 1988. Two tunnels extend out from the complex and house highly contaminated rail cars, along with other highly contaminated equipment.
PUREX made the news in May 2017, when a portion of the roof of PUREX Storage Tunnel 1 collapsed. Throughout the rest of 2017, workers stabilized Tunnel 1 by pumping in engineered grout to encase and cover the highly radioactive materials stored in the tunnel. Following public comment, we allowed Energy to also grout Tunnel 2.
Another of Hanford's canyons, T Plant, is the oldest nuclear facility in the country still operating with a current mission, although its current mission is quite different than it was decades ago. Today, T Plant is a decontamination and repair facility where workers treat, verify, and repackage radioactive and hazardous waste. Gases trapped in drums of waste are also sampled.
Highly radioactive sludge from the K West Reactor fuel storage basin is also being temporarily stored at T Plant.
Ultimately, plans are to decontaminate and demolish each canyon.
A view of Hanford's 300 Area, taken in September 2015. (Photo courtesy: USDOE)
A worker stands next to the 324 Building's B-Cell. (Photo courtesy: USDOE)
Hanford's 324 Building in January 2020.
300 Area
Hanford's 300 Area is the part of the site closest to the city of Richland, near the Columbia River.
The area included fuel manufacturing operations during plutonium production years, as well as experimental and laboratory facilities. During production years raw uranium was brought into the 300 Area to be manufactured into fuel rods for Hanford's nine plutonium production reactors.
Cleanup of the 300 Area entails the decommissioning, deactivation, decontamination, and demolition of hundreds of buildings and facilities. A lot of the work is done, but more remains, such as cleanup of numerous solid waste burial grounds and the 324 Building.
324 Building
The Chemical Materials Engineering Laboratory, more commonly known as the 324 Building, is one of the last major facilities yet to be demolished in the 300 Area.
Parts of the building are highly contaminated and include a number of both radiological and non-radiological laboratories, administrative areas, and other support facilities.
Demolition and cleanup of the 324 Building, already a dangerous and complex task, was made more difficult after a breach in the area below the B-Cell was discovered, revealing highly radioactive contamination in the soil beneath the facility.
A number of contamination incidents have happened during cleanup so far. However, our agency will continue to monitor the site and take any necessary action.
Hanford's massive landfill, known as the the Environmental Restoration Disposal Facility (ERDF), is located in Hanford's 200 area and was originally constructed in 1996. Since being built, ERDF has seen four major expansions, most recently in 2011. The landfill is regulated by the EPA.
ERDF accepts only Hanford waste including low-level radioactive, hazardous, and mixed waste. The landfill has taken in more than 19 million tons of waste.
IDF
The Integrated Disposal Facility (IDF) is another landfill located near the center of the Hanford Site. IDF has a much smaller capacity, about one million cubic meters, and currently has two disposal cells. IDF began accepting vitrified low-activity waste in April 2026.
Both ERDF and IDF are built in such a way to catch liquids not meant to be stored at the landfills, which are then treated and returned to the soil. The two facilities can be expanded if needed.
The 200 West Groundwater Pump and Treat System.
Six groundwater pump and treat facilities were built to treat billions of gallons of contaminated groundwater throughout the Hanford Site. Operations began in the 1990s.
The facilities remove various contaminants such as cesium, strontium, hexavalent chromium, tritium, carbon tetrachloride, and more. To date, the pump and treat facilities have treated more than 38 billion gallons of groundwater.
Five of the pump and treat stations are in the 100 area of the Hanford Site near the D, DR, H, K-West, and K-East Reactors. The sixth is in the 200 West Area on Hanford's central plateau and is the largest.
The 200 West Groundwater Pump and Treat System has the ability to treat up to 2,500 gallons of water per minute. The pump and treat systems are fed by extraction wells throughout the Hanford Site. Treated water is injected back into the ground. Work is underway to increase treatment capacity to 3,750 gallons per minute.
For more information on groundwater treatment, check out the U.S. Department of Energy's annual soil and groundwater reports.
Deer stand in front of Hanford's cocooned D Reactor.
Of the 586 square miles making up the Hanford Site, only a small portion of that was used for plutonium production. The rest acted as a security and safety buffer, thereby leaving many areas virtually untouched.
A main area of focus in the present day is maintaining and protecting the land, water, and wildlife throughout the Hanford Site. Part of the cleanup mission is also to restore impacted areas.
One such area not used for plutonium production is the Arid Lands Ecology Reserve (ALE), the only remaining sizeable shrub-steppe ecosystem in Washington state. The ALE is located between the northeast-facing portion of Rattlesnake Mountain and State Highway 240.
The ALE is managed by Hanford Mission Integration Solutions for Energy.
The Hanford Site also features: the largest fall Chinook salmon spawning area in the Columbia River system, the longest free-flowing stretch of the Columbia River above Bonneville Dam, and many sites with unique and irreplaceable historic, cultural, and scientific heritage.
