In August 2002, the City and County of Denver conducted a Curbstone Preservation and Decontamination Study on 11th Avenue between Gaylord Street and Race Street to determine the economic and environmental viability of preserving the historic curbstone during future reconstruction and remediation of 11th Avenue.

Study Results

The work included removing asphalt and road materials for approximately nine feet from the curb and cleaning the curbstone to remove any radium-contaminated materials. The study determined the existing curbstone or curb and gutter could be preserved during future remediation of 11th Avenue and other radium streets. This is very significant both from an impact and cost perspective. In terms of impacts, the study found that historic curbstone could be preserved to maintain the historic nature of 11th Avenue. By preserving the curb, whether curbstone or curb and gutter, the impact to the residents will be reduced significantly as construction activity will occur within the roadway and will not disrupt landscaping or sidewalks adjacent to the project area. The duration of construction will be reduced with the ability to leave existing curb in place. In terms of cost, maintaining existing curbs significantly reduces the cost of removal, transport and disposal of material by reducing the amount of material. The cost of reconstruction is reduced by not having to rebuild curb and gutter and by reducing the impact outside the traveled way.

Beyond the physical impacts of construction discussed above, the City was able to document that its current practices meet or exceed EPA standards for managing radium materials. The process of cutting the material and enclosing it in sealed containers for transport and disposal was monitored and no releases of radioactive materials were found. After removal, the radioactive levels found in the street were less than the background levels of activity, indicating the remediation effort was very effective.

In the long term, the City believes that the potential impact to residents along radium streets will be eliminated with the permanent removal of radium-contaminated material.