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Who Was the Rocky Flats Cleanup Designed to Protect? A 2001 Report Asked Us to Think About Future Generations
Before the accelerated cleanup was completed, independent researchers questioned whether the standards being developed for Rocky Flats would adequately protect people hundreds or thousands of years into the future.
A question that goes beyond the cleanup
When Rocky Flats was undergoing an accelerated cleanup, one of the most important decisions wasn't simply how much contaminated soil would be removed. It was how clean the soil needed to be before the site could be declared cleaned up. In December 2001, the Institute for Energy and Environmental Research (IEER) published a report titled Setting Cleanup Standards to Protect Future Generations. Written by Dr. Arjun Makhijani and Sriram Gopal for the Rocky Mountain Peace and Justice Center, the report examined the scientific basis for setting limits on radioactive contamination remaining in soil.
The researchers questioned whether cleanup standards should rely on the assumption that Rocky Flats would remain a wildlife refuge with restrictions on how people could use the property. Their concern was straightforward: What happens when radioactive contamination lasts far longer than the laws, government institutions, and land-use designations intended to manage it? More than two decades later, that question remains relevant to understanding the history of Rocky Flats and the decisions that shaped its future.
What is a radionuclide soil action level?
A radionuclide soil action level, or RSAL, is a concentration of radioactive material in soil used to determine when cleanup action is required. At Rocky Flats, plutonium contamination was a particular concern because of its use in nuclear weapons production and the site's history of fires, leaks, waste handling, and environmental releases. Soil concentrations of plutonium are commonly expressed in picocuries per gram (pCi/g), a measurement of radioactivity per unit mass. A cleanup action level is not necessarily a guarantee that all soil below that concentration contains no contamination or presents no risk. Instead, it is part of a regulatory framework developed using assumptions about potential exposure, future land use, and acceptable risk. Those assumptions can have enormous consequences. The standard selected helps determine where soil must be removed, where it may remain, and what controls may be needed afterward.
The central disagreement: Wildlife refuge or future residential use?
At the heart of the IEER report was a disagreement over how to evaluate potential future exposure. The researchers supported an approach known as the subsistence farmer scenario.
Under this scenario, risk assessments consider a hypothetical future person who lives on the land, uses local water, raises food, and consumes locally produced crops and animal products. The purpose is not to predict that Rocky Flats will actually become farmland.
It is to create a reasonably conservative exposure scenario that accounts for several ways people could encounter contaminants. The authors argued that the scenario provided a scientifically defensible basis for protecting future generations, particularly when no one can reliably predict how land will be used centuries from now. They were concerned that designating Rocky Flats as a wildlife refuge could lead to less stringent cleanup standards based on an expectation of limited human activity. But land-use designations can change.
Governments change. Policies change. Communities grow. Records can be lost. The researchers questioned whether restrictions adopted today could reasonably be assumed to remain effective across the extraordinarily long periods during which plutonium persists.
Plutonium-239 has a half-life of 24,100 years
One reason long-term cleanup decisions are so important is the radioactive half-life of plutonium-239. Plutonium-239 has a half-life of approximately 24,100 years. That means that after 24,100 years, approximately half of the original plutonium-239 atoms will have undergone radioactive decay. The material can persist through many generations of human history. Its presence alone does not determine an individual's exposure or health risk. Those depend on its concentration, physical and chemical form, environmental movement, and whether it enters the body. Nevertheless, a material that remains radioactive over such timescales presents a challenge for environmental management. The IEER authors argued that decisions should not rely too heavily on the assumption that future generations will maintain the same land-use restrictions adopted today. Their approach was based on protecting people under plausible future uses, rather than requiring future generations to continue managing the consequences of contamination left behind.
What cleanup levels did IEER recommend?
The report proposed considering soil action levels of 1–10 picocuries of plutonium per gram of soil, based on the subsistence farmer approach. That recommendation was considerably more stringent than the interim cleanup level of 651 pCi/g established under the 1996 Rocky Flats Cleanup Agreement. The report also discussed an independent assessment by Risk Assessment Corporation that recommended an action level of approximately 35 pCi/g.
These figures reflect different analyses and assumptions, not directly interchangeable measurements of the actual contamination remaining at every location. The IEER report was making a recommendation about what cleanup standards should be adopted—not reporting the final conditions of the site.
What standards were eventually adopted?
The accelerated cleanup reached physical completion in 2005. By then, federal and state regulators had agreed on a surface-soil action level of 50 pCi/g of plutonium for the upper three feet of soil. According to a 2006 Government Accountability Office (GAO) report, the agreement also allowed higher concentrations at greater depths under specified conditions.
For soil between three and six feet below the surface, the cleanup framework used a trigger of 3,000 pCi/g, with a lower cleanup endpoint of 1,000 pCi/g where remedial action was required. These were action levels applied within an approved cleanup framework, not blanket statements that every portion of the property contained those concentrations.
The final approach represented a substantial reduction from the original 651 pCi/g interim level for surface soil. However, it remained less stringent than IEER's recommended range of 1–10 pCi/g. The difference illustrates why the scientific assumptions behind cleanup standards mattered so much. The level of contamination regulators determined could remain was shaped partly by assumptions about future exposure and land use.
A debate about responsibility to future generations
The IEER report was not simply a technical argument over measurements. It raised a question about responsibility. The authors argued that environmental cleanup should protect future generations without depending indefinitely on institutional memory, government enforcement, or the continuation of present-day land-use restrictions. They noted that communities and land uses can change dramatically within relatively short periods of history.
Predicting conditions thousands of years into the future is far more difficult. The report challenged the idea that a wildlife refuge designation, by itself, provides a sufficient basis for long-term public-health protection. That is a distinction worth preserving. A wildlife refuge can provide significant environmental and conservation benefits. But designating land as a refuge does not remove radioactive materials from the soil. Nor does the designation itself determine the exposure risks associated with every possible future use.
What did the accelerated cleanup actually leave behind?
The accelerated cleanup removed more than 800 buildings and structures, along with large quantities of contaminated materials and waste. But it did not remove every contaminant associated with Rocky Flats operations. Under the 2006 Corrective Action Decision/Record of Decision, the former property was divided into two principal areas. The Central Operable Unit, approximately 1,300 acres encompassing the former industrial area, remained under Department of Energy management with environmental controls, monitoring, and restrictions on certain activities. The surrounding Peripheral Operable Unit, including much of the former buffer zone, was determined by regulators to require no further remedial action under the applicable standards. Much of that land became the Rocky Flats National Wildlife Refuge.
These were regulatory decisions based on specific assessments and land-use assumptions.
They should not be interpreted as findings that every trace of contamination had been removed. The IEER report is relevant because it challenged the principles underlying cleanup decisions before those decisions became final.
What about wildlife?
The authors also questioned whether a wildlife refuge designation could ensure long-term protection for wildlife itself. They discussed uncertainty about radiation's potential effects on genetic integrity and ecosystems over extended periods. Their concern was that the absence of obvious harm in individual animals would not necessarily establish the absence of longer-term ecological effects. These were scientific arguments and uncertainties raised by the report's authors in 2001—not findings that wildlife populations at Rocky Flats had experienced documented genetic damage. Evaluating present-day wildlife health requires contemporary environmental and biological evidence. Nevertheless, the report demonstrated that cleanup standards could have implications beyond human recreation or residential development.
Why this report still matters to Rocky Flats Downwinders
Rocky Flats Downwinders believes the public should understand not only that an accelerated cleanup was completed, but also how the cleanup standards were developed, what scientific assumptions were used, and what contamination regulators allowed to remain. The 2001 IEER report is an important historical contribution to that discussion. It documents an independent scientific argument for more stringent soil cleanup standards and raises questions about whether present-day land-use restrictions are an adequate foundation for protecting distant future generations. The report does not establish that the completed Rocky Flats cleanup failed to comply with applicable law. It does not determine that current refuge visitors are experiencing harmful exposure. And it does not establish that a particular illness was caused by Rocky Flats. Its importance lies in examining the basis for decisions that continue to shape the site. Those decisions affect how residual contamination is managed, how the public understands the term cleanup, and what responsibilities may continue long after the buildings have disappeared.
The larger lesson
Setting Cleanup Standards to Protect Future Generations asked readers to consider an unusually long timeframe. The scientists were not simply asking whether Rocky Flats could meet a cleanup target by 2005. They were asking whether the decisions made during that process would continue to protect people and the environment long into the future.
The report's conclusions and recommendations should be understood in the context of the cleanup proposals being considered in 2001. But its central question remains relevant:
How do we make responsible cleanup decisions today when the contaminants involved may persist for tens of thousands of years? For Rocky Flats Downwinders, understanding that question is part of understanding what an accelerated cleanup actually meant. The buildings are gone. The land has changed. But the decisions about what could remain—and why—are still part of the Rocky Flats story.
The story didn't end when the plant closed.
Read the Original Research
Setting Cleanup Standards to Protect Future GenerationsThe Scientific Basis of the Subsistence Farmer Scenario and Its Application to the Estimation of Radionuclide Soil Action Levels (RSALs) for Rocky Flats
Arjun Makhijani, Ph.D., and Sriram GopalInstitute for Energy and Environmental Research, December 2001Prepared for the Rocky Mountain Peace and Justice Center
Additional government records
