2. Location In the mountain of Colorado consist of numerous sites in Denver area which contaminate with radioactive soils and Debris. There are about 65 properties organized into 11 Operable Units (OUs). History Early 1990: Denver was the site of radium processing activities. 1920 : Plant close, leaving behind the land contaminated with radioactive soil and debris. 1940 : Brick and tile facility operated on the property and leave the site vacant after closing 1979 : EPA discovered the situation 1983 : Operated the Superfund site in September 1983

3. Problem and environmental concerns - Soils were contaminated with the radioactive elements radium, thorium, and uranium. The radioactive decay of these elements produces radon gas and radon daughters. - The critical pathway is the potential for buildup of radon gas and radon daughters in structures built over contaminated deposits. Chronic exposure to radon has been shown to cause lung cancer. In addition, direct contact with the contaminated soils or debris may pose a risk.

4. Contaminants Detected Ground Water Surface Water AirSoilOther RADIUMXXX EPA Hazard Ranking System scores for DENVER RADIUM SITE:Hazard Ranking System Less Hazard National Average More Hazard 0%0% 50 % 10 0 %

5. Partners - U.S. EPA - State of Colorado - The Home Depot, Inc – Buying site to build a new store Solution & Remediation - excavate radioactive soils and materials - Contaminates buildings and materials removed - Metal – contaminated soil covered with protective cap

6. Site Remediation - The remedial action for most of the Operable Units (OUs) consisted of excavation of contaminated materials and disposal at a licensed facility in western Utah. Cleanup activities have been completed at all operable units except Operable Unit 8. -Remediation at Operable Unit 8, Shattuck Chemical Company, involved excavating and treating the contaminated soils with cement and fly ash and placing the solidified and stabilized soils back on site, creating a structure which was capped. -EPA concluded that the long-term protectiveness of the remedy could not be guaranteed, and therefore decided to remove the stabilized waste to a licensed disposal or recycling facility.

7. OU8 Shattuck Chemical - EPA selected off-site removal which offers benefits including: Long-term protection of human health and the environment. Removal of potential source material for future ground-water contamination. Disposal of material in a permitted facility. Unrestricted future land use. -Demolition and off-site disposal of the existing monolith raised concerns about the potential for dust and soil blowing off the monolith => Area being worked is covered with a structure. -The structure selected is a moveable "mining" structure made of sheet metal and tensioned fabric links => allows it to compress and be moved more easily across the site. -A metal conveyor structure will move the mined monolith materials from the moveable mining structure to a metal load out structure where rail cars will be filled. The rail cars will use a newly constructed Shattuck site rail siding to move from the site and connect with the main rail line for off-site transportation. -After the contaminated soils and materials are removed, the site will be verified to be clean and restored. Clean excavation and fill material will be backfilled into the open area where the contamination was removed. The fencing around the site will be removed.

8. Site Map

9. Inside Mobile Mining Structure Loaded Rail Cars

10. Environmental and Social benefits - Protect public health - Prevented spread of radio activity - Improve quality of the area - Attracted consumers to other business in area Economics benefits In Short-term - Employment rate increased - More total annual income from clean-up jobs and redevelopment jobs In Long-term - 113 Permanent jobs with The Home depot - More total annual income from total annual spending - Properties value increased