PB99-963110
EPA541-R99-040
1999
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Treasure Island Naval Station
Hunters Point Ship Yard Site, Parcel B
San Francisco, CA
10/20/1998
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SFUHO RECORDS CTR
3033-00587
EXPLANATION OF SIGNIFICANT DIFFERENCES SFUND RECORDS CTR
SD"l5 # 46832
Parcel B, Hunters Point Shipyard Site
San Francisco, California
August 24,1998 ~
I. Introduction
This Explanation of Significant Differences ("BSD") is for a change to the remedy
selected hi the Record of Decision for Parcel B, Hunters Point Shipyard dated October 7,1997
("Parcel B ROD"). The selected remedy for Parcel B included the excavation of contaminated
soils to the groundwater table, offsite disposal of the excavated soils, ground water monitoring to
ensure protection of San Francisco Bay from contaminated groundwater and institutional
controls prohibiting all uses of groundwater and governing handling of any residual
contaminated soils.
Hunters Point Shipyard (the "Site") is a deactivated Naval base located in San Francisco,
California. In 1989, the Site was placed on the National Priorities List ("NPL") and in 1991 was
selected for closure under the Base Realignment and Closure ("BRAC") program. The lead
agency for investigation and cleanup of the Site is the United States Navy ("Navy"). The lead
support agency is the United States Environmental Protection Agency, Region IX ("EPA").
State support agencies include the California Environmental Protection Agency, Department of
Toxic Substances Control ("DTSC") and the Regional Water Quality Control Board
("RWQCB").
Preparation and public notice of this ESD is required pursuant to section 117{c} of the
Comprehensive Environmental Response, Compensation, and Liability Act ("CERCLA" or
"Superfund"), 42 U.S.C. section 967 l(c). This ESD will become part of the Administrative
Record for the Site. The Administrative Record is available for review at two information
repositories: the Anna E. Waden Branch Library located at 5075 Third Street in San Francisco;
and, the City of San Francisco's Main Library located at 100 Larkin, during normal library hours.
In the Parcel B ROD, the Navy's selected remedy for contaminated soils located on
Parcel B was excavation to the groundwater table followed by offsite disposal. The depth to
groundwater below Parcel B was believed to typically occur at 10 feet below ground surface
("bgs"). However, in early 1998, fieldwork on the Site indicated that the depth to groundwater
beneath Parcel B could be as shallow as 2.3 feet bgs. This ESD revises the selected remedy of
the Parcel B ROD to require cleanup of contaminated soils to a cleanup level of 10"6 cancer risk
(residential) or to a maximum depth of 10 feet bgs instead of to the groundwater table to ensure
that the Parcel B remedy is protective of human health and the environment.
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II. Summary of Site History and Selected Remedy
The Site is a deactivated shipyard located in southeastern portion of San Francisco,
California, adjacent to San Francisco Bay. In 1940, the Navy obtained ownership of the shipyard
for ship building, repair and maintenance activities. After World War II, activities shifted from
ship repair to submarine servicing and testing. Between 1976 and 1986, the Navy leased most of
the Site to Triple A, a private ship-repair company. The Site was an annex of Naval Station
Treasure Island until March 1994 when the Navy's Engineering Field Activity West in San
Bruno, California assumed management of it. The Site consists of 936 acres, 493 on land and
443 under water in San Francisco Bay.
In 1987, contamination was confirmed at a number of Site locations. This finding,
combined with the proximity to an off-site drinking water source (the aquifer used by the Albion
Springs water bottling company), resulted in the EPA placing the Site on the National Priorities
List ("NPL"), in 1989. In 1991, the Department of Defense listed the Site for closure.
In January 1992, the Navy, the EPA, DTSC and RWQCB entered into a Federal Facilities
Agreement to better coordinate the environmental investigation and cleanup of the Site. To
expedite the investigation and cleanup, the Site was divided into six parcels. Each of the six
parcels was assigned a letter to it, ranging from A to F. Parcel F is an offshore parcel.
Fieldwork has been completed for all six parcels. The fieldwork showed that the soils and
groundwater of the Site are contaminated with a variety of hazardous substances including
metals, polychlorinated biphenyls ("PCBs"), volatile organic compounds ("VOCs"), semi-
volatile organic compounds ("SVOCs"), polyaromatic hydrocarbons ("PAHs"), and pesticides.
In addition, total petroleum hydrocarbons (TPH) are present in Parcel B soil and groundwater. A
no-action Record of Decision was signed for Parcel A in November 1995. Little contamination
was detected on Parcel A and Navy intends to transfer Parcel A to the City of San Francisco in
Fiscal Year 1999. Remedial investigations and feasibility studies continue for Parcels C through
F. A number of non-time critical removals have also been completed at the Site. All six parcels
are scheduled to reach final remedy decisions by the end of 1999 and upon cleanup be transferred
to the City of San Francisco. -
In the Parcel B ROD, with regard to contaminated soils the Navy selected excavation and
offsite disposal as the final remedy. The major components of the selected remedy for the Parcel
B contaminated soils are:
o Excavation of contaminated soil to the groundwater table or to a 10"6
excess lifetime cancer risk (residential).
o Offsite disposal of the contaminated soil.
o Placement of clean backfill in the excavated areas.
o Deed notification that soil below the groundwater table in remediated
areas may be contaminated.
o Institutional controls governing handling of residual contaminated soils.
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The ROD also requires that the groundwater be monitored for up to 30 years to ensure
that contamination plumes do not impact the San Francisco Bay and so that VOC contamination
present at IR-10 does not result in air pathway exposures at unacceptable levels. In addition,
steam and fuel lines are to be removed, the storm drains are to be lined and pressure grouted as
appropriate and all future uses of groundwater will be prohibited by a deed restriction. This BSD
addresses only the soil portion of the Parcel B selected remedy.
III. Description of Significant Differences and the Basis for those Differences
During the remedial investigation for Parcel B, human health risks posed by Parcel B
soils were evaluated to a depth of 10 feet. This depth was selected because residential
construction scenarios (house foundations, swimming pools, etc.) typically occur at depths of 10
feet or less. In addition, the proposed reuse plan for Parcel B includes utilities at 8 feet bgs.
Finally, the community expressed an interest in growing produce on Parcel B in conjunction with
residential reuse.
Early drafts of the Parcel B ROD required cleanup of contaminated soils to a depth of 10
feet. The depth to groundwater beneath Parcel B was believed to average from 8 to 10 feet bgs.
In one of the final drafts, the Parcel B ROD was revised to include language requiring cleanup to
the groundwater table. Since remedial investigation and feasibility study data indicated that the
average depth to groundwater was 8 to 10 feet bgs, the change to the selected remedy appeared to
be minimal so the revision was included in the Parcel B ROD.
After the Parcel B ROD was signed in 1997, the Navy took groundwater measurement
levels in early 1998 in the vicinity of several Parcel B installation restoration ("IR") sites as part
of a soil gas treatability study. These were the first groundwater measurement levels taken on
Parcel B since 1995. The water level measurements found that groundwater beneath Parcel B to
be as shallow as 2.3 feet to 4 feet bgs.
Since reuse of Parcel B will include residential uses, such as housing, excavation of
contaminated soil to the groundwater would not be adequately protective because during the
1997-98 rainy season, depths to groundwater beneath Parcel B were measured as shallow as 2.3
to 4 feet bgs. Further, the institutional controls outlined in the Parcel B ROD would no longer be
protective of construction workers during redevelopment of the property. This is because if the
redeveloper believes that all soils below the groundwater table have been cleaned up and the
groundwater table fluctuates and exposes soils that have not been cleaned up, the workers could
be exposed to residual contaminated soils while believing they are protected as long as they do
not dig into the saturated zone.
This BSD revises the Parcel B ROD to include cleanup of contaminated soils to a cleanup
level of 10^ cancer risk (residential) or to a maximum depth of 10 feet bgs to ensure that the
Parcel B remedy is protective of human health in both the short and long term.
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IV. Support Agency Comments
In a letter dated June 26,1998, the State of California Regional Water Quality Control
Board concurred with this BSD for Parcel B. The BRAC Cleanup Team (BCT) representative
for the State of California Department of Toxic Substances Control for the Hunters Point Site
reviewed the Draft BSD for Parcel B and only had minor comments, all of which are addressed
in this Final BSD for Parcel B. ~
V. Affirmation of the Statutory Determinations
It is the determination of the Navy, the EPA, and the State of California that this modified
remedy continues to satisfy the statutory requirements of cleanup under the Superfund process.
Considering the information that has been developed during implementation of the remedy and
the proposed changes to the selected remedy, the Navy, the EPA, DTSC and the RWQCB
believe that the remedy will remain protective of human health and the environment, will comply
with Federal and State requirements that are applicable or relevant and appropriate to this
remedial action, and will be cost effective. In addition, the revised remedy will continue to use
permanent cleanup solutions for the Site to the maximum extent practicable. However, the
revised remedy still does not satisfy the statutory preference for remedies that employ treatment
to reduce toxicity, mobility and volume as a principal element. This is due to numerous
comments received during the public comment period voicing strong opposition to on-site
treatment and disposal contaminated soils, the alternative initially proposed by the Navy in its
Proposed Plan for the Parcel .B contaminated soils. In response to community concerns, the
Navy selected excavation and off-site disposal for the Parcel B contaminated soils.
VI. Public Participation Activities
The Administrative Record for this Site is available for review and comment by any
member of the public at the two information repositories mentioned in Section I of this BSD. No
public meetings are proposed for this BSD unless public interest indicates that such a meeting is
warranted. However, the Navy intends to discuss this BSD for Parcel B with the Restoration
Advisory Board for Hunters Point Shipyard at its next scheduled meeting.
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Adichael McClelland Date
BRAC Environmental Coordinator
Hunters Point Shipyard
Daniel Opalski Date
Chief
Federal Facilities Cleanup Branch
U.S. Environmental Protection Agency Region IX
Anthony J. L^fali^X Date
Chief, Northern California Operations
Office of Military Facilities
Department of Toxic Substances Control
California Environmental Protection Agency
Loretta K. Barsamian Date
Executive Director
California Regional Water Quality Control Board
San Francisco Bay Region
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