What is the current configuration and management at the Rocky Flats site?

The final remedial decision created two areas:

Central Operable Unit (COU)

  • Includes the former Industrial Area where manufacturing activities took place.
  • The 1,308-acres area is retained and managed by the Department of Energy.
  • The area contains all engineered elements of the remedy (two landfills plus four groundwater treatment systems) and areas of residual subsurface contamination.
  • Institutional controls include prohibiting construction of buildings, excavation, drilling and use of groundwater or surface water.
  • Following remediation, confirmation samples from surface soil in the Central Operable Unit averaged 2.3 picocuries (trillionths of a curie) per gram (pCi/g), which is below levels of regulatory concern (50 picocuries per gram). 
  • Surface water and groundwater are routinely monitored.
Peripheral Operable Unit (POU)/ Rocky Flats National Wildlife Refuge 
  • The Peripheral Operable Unit consists of part of the former security Buffer Zone, where contaminant levels did not require remediation. Residual plutonium levels in surface soil in the Peripheral Operable Unit average about 1.1pCi/g. These concentrations are below levels that are protective of human health for any exposure scenario. 
The Rocky Flats National Wildlife Refuge Act of 2001 authorized creation of a refuge following cleanup and expressly prohibited reindustrialization of the site or local government annexation of the property. Nearly 4,000 acres was transferred to the U.S. Fish & Wildlife Service in July 2007. Properties along the western side of the refuge that have been cleared of mineral leases have since been added, bringing the current total acreage to about 5,000 acres. The final decision determined that this portion of the site was in a state that is protective of human health and the environment, where unrestricted and unlimited use is allowed. EPA based its decision to delist the Peripheral Operable Unit from the National Priorities List of Superfund sites on the determination by EPA and the state of Colorado “that all appropriate actions under CERCLA have been implemented to protect human health, welfare and the environment and that no further response action by responsible parties is appropriate.” Delisting pertained to the surface media (soil, surface water, sediment) and subsurface media, including groundwater. 

Rocky Flats two operable units