HomeMy WebLinkAboutCC 10-06-2026 Item No. 10. Approved Remediation Plan for Soil Contamination at The Rise_Staff PresentationCC 10-06-2026
#10
Approved
remediation plan for
soil contamination at
The Rise
Presentation
City Council Informational Item
Eden Housing Environmental Vapor
Barrier and Vapor Intrusion Mitigation
System (VIMS)
Richard Campbell
Special Counsel
Purpose of Informational Session
General overview of
Planned environmental
mitigation at Eden Housing
Project
Vapor Barrier and Vapor Intrusion Mitigation
System (VIMS)
Responsible Agency: Santa Clara County
Department of Environmental Health (DEH)
•Initial soil sampling showed elevated levels of
volatile organic chemicals (VOCs) such as
trichloroethylene (TCE) associated with
industrial solvents, and tetrachloroethene (PCE)
historically used in dry cleaning operations
•DEH is agency overseeing site cleanup under
California Health and Safety Code sec. 101480
What is Vapor Intrusion?
Migration of vapor
from chemical
deposits in
subsurface soils
that rise into
surface structures
PCE and TCE are
such vapor-forming
chemicals
https://www.epa.gov/vaporintrusion/what-vapor-intrusion
Vapor Barrier (i.e. passive mitigation)
The vapor barrier is
designed to stop
soil vapors from
seeping through
the ground into
buildings and
impacting indoor
air quality.
Applicant’s VIMS Basis of
Design Report (2026)
Active Venting System
- If indoor air monitoring indicates that additional
measures are needed, modifications will be made to
the passive system.
- After modifications, follow-up monitoring will confirm
effectiveness of the mitigation measures.
- If monitoring indicates that modifications are not
sufficient, contingent active venting system will be
implemented.
Applicant’s VIMS Basis of Design Report (July 2026)
City Responsibility Limited to Building Code
“[T]he City of Cupertino will not approve the
hazardous materials or soil vapor intrusion
mitigation aspects of the VIMS design plans,
but [City] will review and approve the VIMS
design plans as they relate to applicable
building code, fire code, etc. as part of the
overall building design plans.”
Department of Environmental Health BOD Approval
Letter, September 1, 2026
Post-Occupancy Indoor Air Sampling
At least three long-term verification sampling
events will be conducted following building
occupancy
FIRST: Sampling Event 3 - 6 months
SECOND: Sampling Event 4 - 12 months
THIRD: Sampling Event 5 - 24 months
Questions