Presentation on theme: "VAPOR INTRUSION ISSUES Case Study Experience – Silicon Valley, CA Example of Governmental Agency Actions."— Presentation transcript:
VAPOR INTRUSION ISSUES Case Study Experience – Silicon Valley, CA Example of Governmental Agency Actions
Asset Acquisition, Silicon Valley, CA Palo Alto, California (Stanford Research Triangle) Property located above existing large scale chlorinated solvent plume Single Tenant, Triple Net. Tenant: Prominent San Francisco Law Firm Historical use issues, but inconsequential. New ESA Standard Recommends Vapor Intrusion Evaluation
Approach to Testing Hired Certified Industrial Hygienist Sampling Methodology was vacuum canisters NOTE: Standard methodology, may be too “sensitive”. Controlled methodology for testing HVAC Off (reducing stack effect and outdoor air intake) Testing on Weekends Multiple data points inside and outside building for comparison
Needed to hire a Toxicologist… Toxicologist obtained data that showed that “background” concentrations of dichloroethane was 0.21 micrograms/cubic meter. However, still concluded that “some source of pollution was present within the building” that was “contributing to dicloroethane concentrations within the building.” Conclusion was that although within the 10 -6 cancer risk, it still triggered a Proposition 65 Notification Requirement.