This document discusses one agency's efforts to notify relevant parties about residual soil and groundwater contamination at closed contamination sites. The agency sends quarterly letters and site lists to building and planning departments, issues notification letters at case closure when residual contamination remains, records commercial deed restrictions, and uploads documents to the Geotracker and Envirostor databases. When development is proposed near closed sites, the agency reviews plans, may require soil and groundwater management plans, and can request additional site assessments. Examples discussed include converting an industrial site with residual diesel contamination to residential use, long-term groundwater remediation at a former gas station, and ensuring elevator construction plans at a redeveloped Safeway account for a nearby contamination plume.

1. Dealing with Residual Contamination
One Oversight Agency’s Attempt
CUPA Conference 2013 TH-F2
Charles Ice, P.G.
Groundwater Protection Program
San Mateo County
Environmental Health

2. Outline
• Methodology for providing notification of
residual contamination
• Responses to potentially encountering
residual contamination
• Site specific examples

3. Notification of Residual Contamination
• Quarterly letter and list of all of our sites to all
building/planning/redevelopment agencies
• Building department notification letters at
time of case closure
• Commercial deed restrictions
• Geotracker and Envirostor

4. Quarterly letter and list
• Send a list to all building/planning/redevelopment
agencies within our geographic jurisdiction as part of
our Public Participation Program
• List only includes county lead sites, does not include RB
or DTSC sites
• Regularly contact all of the building/planning/
redevelopment agencies to get correct contact
information and offer to host or attend a meeting with
each of the agencies to explain the list among other
contamination issues
• List also publically posted in county courthouse and
letter asks other agencies to post in public location

5. Building Department Notification
Letter
• Sent at time of case closure when known residual
contamination left in place at concentrations above
either generic or site-specific screening levels
• Identifies all impacted properties but also mention a
potential concern for properties in the vicinity
particularly regarding groundwater extraction
• At current location (i.e. depth) not a threat but should
it be encountered and potentially moved then could be
• Can be entered, but public can not see it, in Geotracker
under Closure/NFA Letter activity as Site Management
Requirements – Notify Prior to Development and
Subsurface Work, No Excavation without Approval

6. Commercial Deed Restriction
• Voluntarily done by property owner (may or may
not be responsible party) to get closure (usually
quicker and with less remediation) under
commercial rather than residential land use
• Modeled (i.e. plagiarized) from DTSC (2006),
double check any citations for relevance to you
versus DTSC only
• Language is 100% negotiable but must have key
elements (described on next slide)
• Cosigned by agency and property owner and
recorded with the Assessor by responsible party

7. Commercial Deed Restriction
• Statement of Facts
– Description of Site and Contamination, Health Effects, Surrounding
Land Use, Finding
• General Provisions
– To Run with the Land, Binding Upon Owners/Occupants, Incorporation
into Deeds and Leases, Conveyance of Property, Cost of Administering
the Covenant to be Paid by Owner
• Definitions
• Restrictions and Requirements
– No residences, schools, day cares, hospitals, hospices, or similar
– No drilling or groundwater extraction except construction dewatering
with appropriate notification
– No disturbing the soil without approval
– Access for department and enforcement
• Variance, Termination, and Term

8. Geotracker and Envirostor
• GeoTracker is maintained by State Water Resources
Control Board
– 9/01 analytical data reports, depth to water
measurements, and latitude, longitude, and elevation of
permanent sampling points for LUST sites only submitted
by responsible party
– 7/05 regulatory requested reports, boring logs, and maps
of sampling points for all types of sites submitted by
responsible party
– 1/08 Regulatory letters submitted by regulatory agency
• Envirostor is maintained by Department of Toxic
Substances Control

9. Responses to Notification
• Notified by either agency official or the project proponent
representatives of development or other work on site
• Ask for plans and compare known historical location of residual
contamination to area (including depths) of proposed activity
• Ask agency that will be issuing the permit for the project to add as a
condition that a Soil and Groundwater Management Plan be
submitted to and accepted by Environmental Health (i.e. mitigation
measure)
• Can also ask for a site specific risk assessment if conditions warrant
(grading or construction causes residual contamination to be closer
to surface or building [i.e. less attenuation zone])
• Proponent pays for all oversight costs

10. Soil and Groundwater Management
Plan
• Plan describes how waste will be identified,
segregated from clean soil and water, handled
and stored, characterized and eventually
disposed (potentially even reused onsite)
• Subsurface garages, basements, piers,
elevators, and even wine cellars
• Dewatering even if only temporary
– What about this on neighboring sites, notification
provided?

11. Industrial to Residential, Menlo Park
• Formerly a construction equipment repair yard, lots of
surface spills particularly around storage sheds
• Excavated diesel contamination to commercial ESLs,
obtained deed restriction, and closed case
• City of Menlo Park sued for not having enough
housing, lost the lawsuit, designated several industrial
areas for residential conversion
• New owner trying to remove deed restriction now
– Use old data to develop remediation plan to residential ESL
– Recharacterize the contaminants to see if either a smaller
area still needs to be remediated or deed restriction is
even needed any more (i.e. attenuation)

12. Olympian gas station, Daly City
• 1996 site was going to be completely
demolished and rebuilt, borings discover
contamination, site opened
• USTs removed with some additional
overexcavation, confirmation samples show
only minor amount of contamination left
• Closed in 2000 with building department
letter

13. Olympian gas station, Daly City

14. Olympian gas
station, Daly City
- Nella purchases
Olympian in 2002
- Prior to purchase,
Olympian does
voluntary investigations
of all of their facilities
so that if contamination
is found at any of them
they can get them into
the Fund
- Found MtBE associated
with new tanks, opened
site in 2002, put in 5
monitoring wells,
significant
contamination only in
MW-1

15. Olympian gas
station, Daly City
- install MW-6 in 2006,
0.85 feet of free
product
- Reopened former site
- 6 DPE wells (MW-6,
MW-16, MW-17, MW-
19, MW-20, MW-22) in
2011
- As of 10/12 ~155,000
gallons extracted
- 12,053 pounds of TPH
removed

16. Safeway remodel, Millbrae
• Safeway directly adjacent, but cross-gradient, to a
recently closed Chevron station case and directly
downgradient from an open dry cleaner site
• Based on the building department letter for the
closed Chevron case, planner contacts county
environmental health during CEQA
• PCE plume found to have no vapor intrusion
impact on Safeway
• Subsurface construction not encountering
groundwater, so no Soil and Groundwater
Management Plan required

17. Safeway remodel, Millbrae
• A few months later, receive a call from an
elevator contractor regarding potentially
encountering contaminated groundwater during
construction of elevator
• A change in the construction of the elevator had
occurred after the original plans were submitted
• Safeway says it was a coordination issue between
the structural engineer and the architect
• Moral of the story – make sure you are dealing
with the final version of the plans