The Rocky Flats Plant was a U.S. manufacturing complex that produced nuclear weapons parts in the western United States, near Denver, Colorado. The facility's primary mission was the fabrication of plutonium pits, which were shipped to other facilities to be assembled into nuclear weapons. Operated from 1952 to 1992, the complex was under the control of the U.S. Atomic Energy Commission (AEC), succeeded by the Department of Energy (DOE) in 1977.
Plutonium pit production was halted in 1989 after EPA and FBI agents raided the facility and the plant was formally shut down in 1992. Operators of the plant (Rockwell) later pleaded guilty to criminal violations of environmental law. At the time, the fine was one of the largest penalties ever in an environmental law case.
Cleanup began in the early 1990s, and the site achieved regulatory closure in 2006. The cleanup effort decommissioned and demolished over 800 structures; removed over 21 tons of weapons-grade material; removed over 1.3 million cubic meters of waste; and treated more than of water. Four groundwater treatment systems were also constructed. Today, the Rocky Flats Plant is gone. The site of the former facility consists of two distinct areas: (1) the "Central Operable Unit" (including the former industrial area), which remains off-limits to the public as a CERCLA "Superfund" site, owned and managed by the U.S. Department of Energy, and (2) the Rocky Flats National Wildlife Refuge, owned and managed by the U.S. Fish and Wildlife Service. The Refuge (also known as the "Peripheral Operable Unit") was determined to be suitable for unrestricted use. Every five years, the U.S. Department of Energy, U.S. Environmental Protection Agency, and Colorado Department of Public Health and Environment review environmental data and other information to assess whether the remedy is functioning as intended. The latest Five-Year Review for the site, released in August 2022, concluded the site remedy is protective of human health and the environment. However, a protectiveness deferred determination was made for PFAS.
History
1950s
Following World War II, the United States increased production of nuclear weapons. The AEC chose the Dow Chemical Company to manage the production facility. A site about northwest of Denver on a windy plateau called Rocky Flats was chosen for the facility. On July 10, 1951, Ground was broken on the first building in the facility. Contemporary news reports stated that the site would not be used to produce nuclear bombs, but might be used to produce uranium and plutonium components for use in nuclear weapons.
In 1953, the plant began production of bomb components, manufacturing plutonium pits which were used at the Pantex plant in Amarillo, Texas to assemble fission weapons and the primary stages of thermonuclear weapons. By 1957, the plant had expanded to 27 buildings.
On September 11, 1957, a plutonium fire occurred in one of the gloveboxes used to handle radioactive materials, igniting the combustible rubber gloves and plexiglas windows of the box. Metallic plutonium is a fire hazard and pyrophoric; under the right conditions it may ignite in air at room temperature. The accident resulted in the contamination of Building 771, the release of plutonium into the atmosphere, and caused $818,600 in damage. An incinerator for plutonium-contaminated waste was installed in Building 771 in 1958.
1960s
Throughout the 1960s, the plant continued to enlarge and add buildings. The 1960s also brought more contamination to the site. In 1967, of plutonium-contaminated lubricants and solvents had accumulated on Pad 903. A large number of them were found to be leaking, and low-level contaminated soil was becoming wind-borne from this area. At least some of the leakage had been detected as early as 1962. Later analysis completed in 1999 for the CDPHE estimated that between 6 and 58 Curies of plutonium spilled on to Pad 903 soil due to barrel leakage. This pad was covered with gravel and paved over with asphalt in 1969.
On May 11, 1969 there was a major fire in a glovebox in Building 776/777. This was likely the costliest industrial accident to occur in the United States up to that time (pre-EPA). Cleanup from the accident took two years. The follow-up accident analysis led to safety upgrades on the site, including fire sprinkler systems and firewalls.