Key Conclusion: ERAS has been using low threat case closure procedures to close leak cases. A solvent leak case in Sunnyvale has been approved for low threat solvent case closure after remediation, groundwater monitoring and risk assessment by ERAS. Other sites currently being closed by ERAS using low threat solvent case closure are in Richmond, Oakland and Milpitas. These closures will allow for bank financing of these additional properties.

The Regional Water Quality Control Board (RWQCB) has implemented this policy (Low Threat Solvent Case Closure) to close leak sites that do not pose a risk human health and safety and the environment. The low threat closure involves closing the site before beneficial uses of groundwater are fully restored. This action only makes sense if a conclusion is reached that cleanup standards can be met under natural conditions within a reasonable timeframe, following completion of cleanup and monitoring. In that sense, it can be thought of as a next step following either additional cleanup or groundwater monitoring.

The low threat solvent case closure being completed by ERAS on Wolfe Road in Sunnyvale will require proper abandonment of twelve groundwater monitoring wells on-site and off-site. In addition, the case closure, for this and other sites, require the following documents to be filed.

  1. Deed Restriction
  2. Site Management Plan (SMP)
  3. Case Closure Summary

The case closure will restrict the use of the Property to the current commercial uses as summarized in the Deed Restriction. If the use of the Property is changed,
additional investigation and/or remediation would likely be required. If subsurface work will impact the subsurface in the area of contamination, precautions are necessary to protect workers as detailed in the SMP.

ERAS has closed or is in the process of obtaining low threat solvent case closure for sites on Wright Avenue in Richmond (RWQCB), Hegenberger Road in Oakland (Alameda County Health Department) and Landess Avenue in Milpitas (Santa Clara County Health Department).

Please contact ERAS if we can assist you with any aspect of case closure or to serve your Phase 2 investigation needs.