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

Consultant Conclusions:

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.