The Rocky Flats Plant was a former nuclear weapons production facility in the western United States, near Denver, Colorado. Operated from 1952 to 1992, it was under the control of the U.S. Atomic Energy Commission (AEC), succeeded by the Department of Energy (DOE) in 1977.
Weapons production was temporarily halted in 1989 after EPA and FBI agents raided the facility. Operators of the plant 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 16 million gallons 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:
- 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...
- 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 to assess whether the remedy is functioning as intended. The last five-year review concluded the remedy is effective. The next five-year review will be produced in 2017.
The Rocky Flats Plant was a former U.S. nuclear weapons production facility about 15 miles northwest of Denver, Colorado, which caused radioactive contamination, primarily plutonium, americium, and uranium, within and outside its boundaries. The facility was dismantled and removed, and the central industrial area of the property became a Superfund site, surrounded by the newly created Rocky Flats National Wildlife Refuge.
The contamination primarily resulted from two major plutonium fires in 1957 and 1969 (plutonium is pyrophoric and shavings can spontaneously combust) and from wind-blown plutonium that leaked from barrels of radioactive waste. Much lower concentrations of radioactive isotopes were released throughout the operational life of the plant from 1952 to 1992, from smaller accidents and from normal operational releases of plutonium particles too small to be filtered. Prevailing winds from the plant swept airborne contamination south and east, into populated areas northwest of Denver.
The contamination of the Denver area by plutonium from the fires and other sources was not publicly reported until the 1970s. According to a 1972 study coauthored by Edward Martell, "In the more densely populated areas of Denver, the Pu contamination level in surface soils is several times fallout", and the plutonium contamination "just east of the Rocky Flats plant ranges up to hundreds of times that from nuclear tests.". As noted by Carl Johnson in Ambio, "Exposures of a large population in the Denver area to plutonium and other radionuclides in the exhaust plumes from the plant date back to 1953.".
In the 1990s, a series of Historical Public Exposure Studies were conducted to assess past releases and public exposures. For example, the figure at right illustrates the calculated lifetime cancer risk to a laborer from the 1957 Rocky Flats fire. The key shows the cancer risk due to exposure during the 1957 event per million persons. This figure means that an outdoor laborer in the reddest part of Arvada would have roughly a two-in-a-million (that is say, a 0.000002%) risk of contracting cancer from being outside during the 1957 fire. The original, complete figure - as well as many others showing the risks of past exposures - can be viewed in the Summary of Findings from the Historical Public Exposure Studies.
Weapons production at the plant was halted after a combined FBI and EPA raid in 1989. Due to the end of the Cold War, changes in nuclear weapons policy, and years of protests, the Rocky Flats Plant was shut down, with its buildings demolished and completely removed from the site. The site's mission then changed to cleanup. The Rocky Flats Plant was declared a CERCLA Superfund site in 1989 and began its transformation to a cleanup site in February 1992. Removal of the plant and surface contamination was largely completed in the late 1990s and early 2000s, with federal and state agency support and stakeholder input. 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 16 million gallons of water. Four groundwater treatment systems were also constructed. The site achieved regulatory closure in 2006.
Today, the site consists of two areas. The "Central Operable Unit" encompasses the former industrial/plant area of the site. This area is still a CERCLA "Superfund" site, retained and managed by the U.S. Department of Energy. Environmental monitoring and sampling are conducted by the Department of Energy here on a regular basis. Remediation efforts are also ongoing in the Central Operable Unit. Four groundwater treatment systems are currently installed and operating in the Central Operable Unit. Every five years, the DOE, EPA, and Colorado Department of Public Health and Environment review environmental data to assess whether the remedy is functioning as intended. The last five-year review concluded the site remedy is effective. However, this area remains off-limits to the public due to residual contamination, and to protect site treatment systems and the integrity of remedial efforts.
The outer "Peripheral Operable Unit" is now the Rocky Flats National Wildlife Refuge. This area was the site's former security buffer zone and did not require remediation. In 2001, the U.S. Congress passed the Rocky Flats National Wildlife Refuge Act, dedicating this buffer zone to conservation. Accordingly, the DOE transferred land ownership of this area to the U.S. Fish and Wildlife Service, which currently exercises jurisdiction over the Refuge. It is anticipated the Refuge will open to the public in 2018.
While the U.S. Department of Energy continues to monitor and collect samples from the Central Operable Unit, a some groups and citizens remain concerned about the extent and long-term public health consequences of the contamination. Estimates of the public health risk caused by the contamination vary. Activist groups are concerned about the potential risks posed by residual contamination, which exists on-Site. However, the Comprehensive Risk Assessment for the site found the post-cleanup risks posed by the site to be very low and within EPA guidelines. A 1998 independent study by the Colorado Department of Public Health and Environment on cancer rates in communities surrounding Rocky Flats also found no pattern of increased cancers tied to Rocky Flats.
1964 to 1967 Pad 903 leakageEdit
1973 t0 1997 leakageEdit
Another major fire occurred on May 11, 1969 in building 776/777 (the Plutonium Processing Facility), again starting due to spontaneous combustion of plutonium shavings in a glove box. Firefighters again resorted to fighting the fire with water after dry extinguishers proved ineffective. Despite recommendations after the 1957 fire, suppression systems were not built into the glove boxes.
While the fire bore marked similarities to the 1957 fire, the level of contamination was less severe because the HEPA filters in the exhaust system did not burn through (After the 1957 fire, the filter material was changed from cellulose to nonflammable fiberglass). Had the filters failed or the roof (which sustained heavy fire damage) been breached, the release could have been more severe than the 1957 fire. About 1,400 kilograms (3,100 lb) of plutonium was in the storage area where the fire occurred, and about 3,400 kilograms (7,500 lb) total plutonium was in building 776/777.
The 1969 fire released 13-62 mCi (140–900 milligrams or 0.00031–0.00198 pounds) of plutonium, about 1,000th as much as was released in the 1957 fire. The 1969 fire, however, led local health officials to perform independent tests of the area surrounding Rocky Flats to determine the extent of the contamination. This resulted in the first releases of information to the public that populated areas southeast of Rocky Flats had been contaminated.
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