Tetra Tech conducted a Remedial Investigation/Feasibility Study (RI/FS) as part of the U.S. Air Force’s Installation Restoration Program (IRP) at Vandenberg AFB. The Base encompasses almost 98,400 acres and supports over 2,000 active and non-active facilities used for rocket launches, satellite tracking, and other Air Force operations, training, and maintenance activities.

A total of 26 IRP sites, the majority of which consist of active and abandoned rocket launch facilities, were evaluated for potential human and ecological risks due to the release of chemical contaminants and other facility activities. The ecological risk assessment provided key input to management decisions since launch facilities were located at or near a number of diverse and sensitive habitats which support numerous special status and ecologically-important species.

Tetra Tech successfully negotiated a phased approach for the human health and ecological risk assessments with California DTSC, RWQCB, Department of Fish and Game, U.S. Fish and Wildlife Service, and National Oceanic and Atmospheric Administration. This included an initial screening level risk assessment to determine whether additional sampling was required. Validated biological, chemical, and physical data were used to develop conceptual site models used as the basis for evaluating the potential for risks to human and ecological receptors and to identify data gaps. Tetra Tech conducted baseline risk assessments and groundwater fate and transport analyses for the 26 sites. The results of the risk evaluations were used to efficiently identify areas requiring additional investigation and to determine the need for and scope of any remediation/mitigation efforts in the most cost-effective manner.