Site Closure Plan and Closure Strategy and Regulatory Support, Former Aerospace Site, Southern California

 A soil vapor extraction system located at former aerospace site in Southern California had operated for a number of years. The client requested a strategy to obtain regulatory site closure. In response, a site closure plan was prepared outlining a schedule and a list of technical and administrative requirements to support site closure. The closure plan also listed methods and procedures to demonstrate that site-specific cleanup concentrations were protective of human health and groundwater. The plan developed a number of cleanup scenarios, and assessed two main risks: groundwater impact pathway through VLEACH Modeling, and indoor vapor intrusion risks with a Johnson-Ettinger Model. The plan was reviewed and approved without modifications by the Office of Environmental Health and Hazard Assessment (OEHHA), and the Los Angeles Regional Water Quality Control Board. The plan was a key document to support the closure process review.