Air Force Plant PJKS is a 464-acre facility near Denver, Colorado, operated by Lockheed Martin Space Systems Company. The U.S. Air Force used it from 1957 to 1968 to test Titan rockets, assemble missiles, and conduct research and development. That work left soil and groundwater contaminated with hazardous chemicals. EPA placed the site on its National Priorities List in November 1989.
Eleven contaminants of concern have been identified at the site. Groundwater contains trichloroethylene (TCE), a cleaning solvent, along with N-nitrosodimethylamine (NDMA), a rocket fuel component, vinyl chloride, cis-1,2-dichloroethene, trans-1,2-dichloroethene, and 1,1-dichloroethene. Soil contamination includes polychlorinated biphenyls (PCBs) in the form of Aroclor 1016, Aroclor 1254, and Aroclor 1260.
The Air Force has led cleanup work across several operable units, which are separate project areas organized by location or contamination type. Workers removed about 6,000 tons of PCB-contaminated soil in October 2001 and performed additional soil removal at 16 locations in October 2005. One location required use restrictions because some PCBs remain capped in place. Radioactive waste, abandoned utilities and wells, and contaminated soil from the D-1 landfill were also removed between 1986 and 2009. A long-term remedy adopted in August 2013 uses bioremediation to treat TCE in groundwater, along with groundwater use restrictions and engineering and land use controls.
Physical construction of the cleanup is complete for the entire site. However, not all cleanup goals for current and reasonably anticipated future land uses have been achieved. There is insufficient data to determine whether human exposures are currently under control or whether contaminated groundwater migration is stabilized. The 2023 Five-Year Review found that contaminant concentrations in some groundwater areas were not decreasing as expected. In response, the Air Force will resume injecting vegetable oil to support bioremediation. Further studies are set to begin in summer 2025 to look at potential risks from vapor intrusion, PFAS (per- and polyfluoroalkyl substances), and 1,4-dioxane. Results are expected in the next Five-Year Review, estimated between August and October 2028. The Agency for Toxic Substances and Disease Registry completed a public health assessment in March 2000 and found the area is not a public health hazard to surrounding neighborhoods.
Community members can review site records at Columbine Library in Littleton, the Colorado Department of Public Health and Environment (CDPHE) Records Center in Denver by appointment, and the EPA Superfund Records Center in Denver. Document copy requests can be made by calling 303-312-7273 or 800-227-8917 ext. 312-7273 (Region 8 only). Direct questions can go to the EPA Remedial Project Manager or to CDPHE.
