Denver Federal Center Facility Investigations (RFIs), Soil Remediation, and Regulatory Compliance

U.S. General Services Administration (GSA) Region 8 PBS Environmental Programs Group (EPG) is required to assess and remediate all areas of contamination at the Denver Federal Center (DFC) according to Colorado Department of Public Health and Environment (CDPHE) Compliance Order on Consent No. 97-07-18-01 issued in 1997. Additionally, the Federal Government’s Strategic Consolidation Plan, a program focused on reducing the federal footprint, has prompted GSA to renovate many of the historical DFC buildings to house new office and lab spaces for federal agencies. The DFC modernization effort has driven environmental cleanup in areas where hazardous waste and hazardous constituents have been disposed or released to the environment.

SSP&A has performed a wide variety of investigation and remediation activities at DFC for GSA and other construction contractors working at the facility. Under three separate contracts with GSA (each with a 4+ year period of performance), SSP&A has prepared and implemented Phase 2 RCRA Facility Investigation (RFI) Work Plans and Corrective Measures Work Plans. Investigative tasks have included:

• Extensive drilling programs to investigate the nature and extent of contaminants, including driller oversight, geologic borehole logging, and composite soil sampling for a full suite of analytes;
• Trench and pothole excavations to explore and identify subsurface anomalies such as buried building debris and abandoned utilities;
• Stormwater investigations to ensure compliance with the DFC National Pollutant Discharge Elimination System (NPDES) permit using tracer dye/flow tests and surface water sampling;
• Surface soil inspections and sampling of over 2,000 pre-established grids throughout the facility; and
• Developing a Human Health Risk Assessment to evaluate the concentrations of arsenic in soil for contractors and landscape workers.

Corrective measures and remedial actions performed include oversight during:

1. Dismantling and clean closure of abandoned features (e.g., dry wells, an oil water separator, sumps, pits, and hydraulic lifts);
2. Large-scale excavations of contaminated soil and Regulated Asbestos Contaminated Soil (RACS); and
3. Solid waste management and handling. To date, SSP&A has been contracted to remove over 14,200 cubic yards (CY) of RACS and 15,800 CY of solid waste (i.e., contaminated soil and debris) in accordance with the Solid and Hazardous Waste Management regulations.

SSP&A provides reporting and sample result screening using the GSA’s site-wide EDVARS, a semi-automated tool used to evaluate the potential for chemical released based on the analytical data and the appropriate cleanup standards. SSP&A’s geochemists perform Level 4 data validation of analytical results; upload and merge field and laboratory data to GSA’s secured site-wide database; provide quality control documentation; and produce reports for GSA and CDPHE review. For each action, a summary of investigation and remediation activities was approved by CDPHE as an Interim Corrective Measures Report or Clean Closure Report.