PB97-963118
EPA/541/R-97/042
November 1997
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Westinghouse Electric Corp. (Sunnyvale)
Sunnyvale, CA
3/14/1997
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION IX
75 Hawthorne Street
San Francisco, CA 94105
EXPLANATION OF SIGNIFICANT DIFFERENCES
FOR THE
1991 RECORD OF DECISION
AT THE
WESTINGHOUSE SUPERFUND SITE
IN
SUNNYVALE, CALIFORNIA
March 1997
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EXPLANATION OF SIGNIFICANT DIFFERENCES
FOR THE
1991 RECORD OF DECISION
AT THE
WESTINGHOUSE SUPERFUND SITE
IN
SUNNYVALE, CALIFORNIA
Introduction
The U.S. Environmental Protection Agency (U.S. EPA) is issuing this
Explanation of Significant Differences (ESD) for the 1991 Record of Decision for the
Westinghouse Superfund Site.
A fact sheet is being sent to community members pursuant to Section 117(c) of
CERCLA in order to provide an explanation of a significant difference to the remedial
action selected in 1991 for the site.
Site Background
The 75-acre Westinghouse property is located at 401 E. Hendy Avenue in
Sunnyvale, Californiafthe site"). The site is bounded by California Avenue to the north,
Hendy Avenue to the south, North Sunnyvale Avenue to the west, and North Fair Oaks
Avenue to the east (see Figure 1). During the mid-1950's Westinghouse manufactured
transformers which contained Inerteen and mineral oil as insulating fluids. Inerteen was
the Westinghouse trade name for an askarel consisting of approximately 60 percent
polychlorinated biphenyl (PCB, Aroclor 1260) and 40 percent trichlorobenzene (TCB).
Inerteen was stored in a 7,000 gallon aboveground storage tank. Mineral oil
was also stored onsite in three 16,000 gallon aboveground storage tanks and one
20,000 gallon underground storage tank. Inerteen liquid and mineral oil were
delivered from their associated tanks to two areas of Building 21 via underground
piping. The Inerteen tank was removed from the Reservoir 2 area in 1971. The mineral
oil tanks were removed prior to 1974. Westinghouse also used Inerteen for weed
control around the perimeter of the property and along railroad spurs on the property.
Both soil and groundwater with the highest concentrations were discovered in
the vicinity of the tanks. The PCB solubility limit of 2.7 ppb was frequently exceeded in
onsite wells located in the source area. Investigations also showed the presence of
PCBs along the top of the A/B1 aquitard. A dense non-aqueous phase liquid (DNAPL)
thickness of 2.8 feet was discovered in well W48, and a light non-aqueous phase liquid
(LNAPL) thickness of 1.1 feet was found in well W3, which is located approximately 70
feet east of the former Inerteen tank. Volatile organic concentrations ranged up to 131
ppb in groundwater.
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Contamination was also found in the soils beneath the underground pipelines
which delivered chemicals to Building 21 for use in the manufacturing processes.
RGB's in soils often exceeded 500 ppm and generally ranged up to 28,000 parts per
million (ppm) from the surface to approximately 45 feet below ground surface.
Enforcement History and selected remedy
The California State Regional Water Quality Control Board (RWQCB) was the
lead agency for the Site from 1981 to 1987. The RWQCB issued Orders 84-63 and
85-94 in 1984 and 1985. Pursuant to these orders, Westinghouse conducted
remediation of shallow soils outside the Reservoir 2 area, and along the railroad spurs
and fence lines.
In October 1984, pursuant to Section 105 of CERCLA, 42 U.S.C. Section 9605,
the Westinghouse Superfund site was proposed for listing on the Federal Superfund
National Priority List (NPL), set forth at 40 C.F.R. Part 300, Appendix B. The listing was
finalized in June 1986. EPA assumed the lead oversight role on December 18, 1987.
An Administrative Order on Consent for the performance of a Remedial Investigation
and Feasibility Study ("RI/FS") was signed by Westinghouse and the EPA on August
20, 1988.
Pursuant to Section 117 of CERCLA, 42 U.S.C. Section 9617, EPA published a
notice of the completion of the Feasibility Study, and of the proposed plan for remedial
action on June 1, 1991, and provided opportunity for public comment on the proposed
remedial action. The public comment period opened on July 1, 1991 and closed on
August 29, 1991.
On October 16, 1991, the U.S. EPA signed a Record of Decision (ROD),
selecting the following remedy:
1. Permanent containment, by means of groundwater extraction, of
contaminated groundwater in the source area where DNAPLs are
detected;
2. Restoration of contaminated groundwater, using extraction, to the
California Department of Health Services (CDHS) Action Level for 1,3-
Dichlorobenzene(1,3-DCB), the proposed maximum contaminant levels
("MCL") for 1,2,4 Trichlorobenzene(1,2,4-TCB) and the federal and state
MCL, with the exception of the standard for PCB(0.5 ppb) in the
onsite source area where DNAPL occurs;
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3. Treatment of the extracted groundwater to meet all applicable or relevant
and appropriate requirements ("ARARs") identified in the ROD for this
discharge, prior to discharge to the onsite storm sewer, unless an
evaluation indicates that an alternative "end-use" for the treated effluent
(such as use for facility process water) can be practicably implemented;
4. Removal of contaminated soil containing greater than 25 parts per million
PCB to a depth of eight feet;
5. Offsite incineration of excavated soils at a federally permitted facility;
6. Institutional controls, such as land use restrictions, to prevent well
construction (for water supply purposes) in source areas that remain
contaminated. Excavation below the eight feet where soil has been
removed will be restricted. Restrictions will also preclude excavation,
other than temporary subsurface work in the upper eight feet and will
require complete restoration of any disturbed fill or the asphalt cap once
any such temporary work was completed;
7. A requirement that EPA receive notification of any future intention to
cease operations in, abandon, demolish, or perform construction in
(including partial demolition or construction) Building 21 (see facility map,
Figure 1);
8. Permanent and ongoing monitoring of the affected aquifers to verify that
the extraction system is effective in capturing and reducing the chemical
concentrations and extent of the aqueous phase plume, and containing
the aqueous phase contamination in the DNAPL source area.
The estimated cost of the remedy in the ROD was $8,300,000. The cleanup
plan outlined in the ROD included leaving contamination above health-based levels in
both soil and groundwater on the Site. In the absence of a known technology to
effectively remove the DNAPL containing PCB from the shallow aquifer, a technical
impracticability waiver was invoked in the ROD. This legal mechanism waived the
requirement to meet the standard for PCB in the source area of the DNAPL. The
waiver was invoked because EPA determined that it is not technically feasible to
remove PCB DNAPL in the a-aquifer source area, which represented 70 percent of the
contaminant mass located in the source area. The other 30% of the total mass of PCB
in this area was thought to be in the vadose zone soils. The ROD requires that this
area be permanently contained and that land use restrictions prevent access to this
contamination. Compliance points were set at the perimeter of the DNAPL source area
in the groundwater. The PCB standard must be met at the following well points: W10,
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W24, W26, W30, W31, W43, W44, W54, W55, W57, W58, W60, W63, W64, W65,
W66, and CCG-2.
Soil cleanup levels were determined based on the historical industrial use of the
property, a land use restriction of continued industrial and/or commercial use, and the
possibility of workers coming into contact with contaminated soil. The aquifers beneath
the site are classified as potential drinking water sources.
Remedial Design/Remedial Action Enforcement History
On February 6, 1992, Westinghouse initiated the work for the remedial design for
the selected remedy pursuant to an Administrative Consent Order for Remedial Design
(U.S. EPA Docket No. 92-08, February 6, 1992). In accordance with CERCLA Section
122, 42 U.S.C. Section 9622, EPA issued special notice to Westinghouse on March 31,
1992.
On September 29, 1993, EPA issued an Administrative Order for Remedial
Design and Remedial Action for the Westinghouse site (U.S. EPA Docket No. 93-05).
The 1993 Order directed Westinghouse to implement the Remedial Design by
performing the Remedial Action and terminated Docket No. 92-08 except for provisions
relevant to EPA's Response Costs.
The remediation contractor mobilized at the site on October 3, 1994.
Approximately 1100 tons of contaminated soils was excavated and sent to Aragonite,
Utah for incineration. A 20,000 gallon underground storage tank was removed as one
of the first tasks of the remedial action. Three monitoring wells and six extraction wells
were also installed as part of the groundwater treatment system. Pipelines containing
mineral oil and Inerteen were removed from approximately 585 lineal feet of pipeline
trench. The designated remedy was constructed between October 3, 1994 and June
1995. The completion reports documenting construction of the groundwater treatment
system and removal of contaminated soils were submitted during March and April of
1996.
Site Ownership
On March 1, 1996, the Northrop Grumman Corporation acquired the
Westinghouse Electronics Systems Group. This acquisition included the site.
Northrop Grumman Corporation is a designer, systems integrator and manufacturer of
military surveillance and combat aircraft, defense electronics and systems, airspace
management and information systems, marine propulsion, precision weapons and
commercial and military aerostructures. The company employs more than 48,000
people, and reported 1995 sales of $6.8 billion.
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SUMMARY OF REMEDY MODIFICATIONS
North Parking Lot Background
Westinghouse Electric Corporation informed EPA in 1993 that they were
interested in the beneficial redevelopment of the North Parking Lot, which is located
across California Avenue from the main plant property. Their contractor conducted
Phase I characterization of this area in preparation for selling this land. The
characterization occurred in three phases that were reported in letters from EMCON to
Westinghouse dated May 6, 1992, August 11, 1992, and July 14, 1993. Copies of
these reports were submitted to EPA during 1993. Except for a single sampling point
(PCB 729 ppm), PCBs were detected in the Parking lot at concentrations no greater
than 210 ppm. The average PCB concentrations found in the North Parking Lot was
150 ppm. Westinghouse has stated their belief that the presence of the PCB's in this
area are a result of spraying of PCB fluids as a weed killer.
Westinghouse subsequently requested that EPA provide a determination of
whether or not the North Parking Lot was part of the Superfund site. They also
requested that any soil remediated from the North Parking Lot allow the alternative
disposal of land filling rather than incineration. EPA determined that the North Parking
Lot was included as part of the site description in the Record of Decision and was
included in the original listing package. Therefore, the North Parking Lot is subject to
the provisions of the ROD.
EPA and Westinghouse/Northrop reviewed historical aerial photographs and
past sampling data. As a result, EPA does agree that the source of the soil
contamination located in the North Parking Lot appears to be reflective of PCB's used
as a weed killer. Contaminated soils removed from the source area in 1994-5
contained average PCB concentrations of 25,000 ppm, which is much higher than the
average 150 ppm levels found in the North Parking Lot.
REMEDY CHANGE
LANDFILLING OF NORTH PARKING LOT SOILS
This ESD is written to change the disposal method for PCB contaminated soils
removed from the North Parking Lot area only. Federal regulations for PCBs are
derived from the Toxic Substances Control Act (TSCA) and the Resource Conservation
and Recovery Act (RCRA). This change in disposal method for PCB contaminated
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soils only applies to soils where contamination is thought to have been a result of using
PCB's as a weed killer. All soils with PCB concentrations greater than 25 ppm will be
excavated. Soils containing PCB concentrations between 25 ppm and 50 ppm be
disposed of at a facility that meets the provisions of RCRA Subtitle C. This ESD will
allow excavation and transportation to a TSCA Chemical Waste Landfill soils found in
the parking lot with concentrations greater than 50 ppm and less than 500 ppm. The
landfill chosen must meet the requirements for TSCA Chemical Waste Landfills as
described in 40 CFR Section 761.75, and must be in compliance with the procedures
for planning and implementing offsite response actions described in 40 CFR Section
300.440. All soils found during this excavation that have PCB concentrations greater
than 500 ppm will be incinerated as required in the 1991 ROD.
The 1991 ROD also contains a provision for Institutional Controls at the site.
The 25 ppm cleanup number is applicable for industrial land use only. The North
Parking Lot can only be used for industrial and or commercial applications. A copy of
this ESD must also be filed with the deed in the County Recorder's Office along with a
map showing the specific areas to which it applies.
JUSTIFICATION FOR CHANGE OF DISPOSAL METHOD
TSCA was listed as a "to be considered" ARAR in the 1991 Record of
Decision. TSCA regulations and OSWER Directive No. 9355.4-01 define PCB
"principal threat" as soils containing greater than 500 ppm PCB. All soils found
in the plant area were deemed "principal threat", therefore EPA's decision was to
remove and incinerate those soils. The TSCA regulation allows for landfilling or
incineration for soils found with concentrations less than 500 ppm. Sampling
results show that soils contaminated with PCB in the North Parking Lot contain
average concentrations of 150 ppm. Therefore, in accordance with 40 CFR
Section 761.60, Disposal requirements, Westinghouse/Northrop may dispose of
soils recovered from the North Parking Lot with PCB concentrations less than
500 ppm in a TSCA approved Chemical Waste Landfill.
SOIL CLEANUP SCHEDULE
In a letter dated April 23, 1996, EPA directed Westinghouse/Northrop to submit
a Workplan for the removal of PCB's with concentrations greater than 25 ppm from the
Parking Lot. Westinghouse/Northrop submitted the Remedial Action Work Plan for the
North Parking Lot on December 20, 1996. Cleanup of the North Parking Lot will start
during April 1997.
Approximately 1000 tons of contaminated soil, with PCB concentrations between
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25 and 50 ppm will be excavated from the North Parking Lot. Soils will be sent to the
RCRA Sub-title C Section of the Laidlaw Facility, which is located in Buttonwillow,
California. This facility is located 36 miles west of Bakersfield, California.
Approximately 1500 tons of contaminated soil, with PCB concentrations between 50
and 500 ppm will also be excavated from the North Parking Lot and sent to Grayback
Mountain. Grayback Mountain is a TSCA facility operated by U.S. Pollution Control,
Inc., and is located 85 miles west of Salt Lake City, Utah. Westinghouse/Northrop
does not expect to encounter any soils with concentrations greater than 500 ppm. If
these "principal threat" soils are encountered they will be sent to the Aptus Facility in
Aragonite, Utah for incineration. This facility is located approximately 80 miles west of
Salt Lake City, Utah. Addresses and phone numbers for these approved disposal
facilities are given in Appendix 1.
The North Parking Lot excavation and removal is scheduled to be completed by
June 1997. Westinghouse/Northrop anticipates the transfer of approximately three
acres of the North Parking Lot to the new property owner during June 1997. The new
owner will construct a commercial building on the three acres purchased and the
Westinghouse/Northrop acreage will remain a parking lot for the near future.
Opportunity for Public Participation:
This Explanation of Significant Differences and the Remedial Action Workplan for the
North Parking Lot Soils will be placed in the local repository.
The local repository for the Westinghouse Superfund Site is:
Sunnyvale Public Library
665 West Olive Avenue
Sunnyvale, CA 94088
Documents will also be maintained at:
U.S. EPA Region 9
Superfund Records Center
95 Hawthorne Street
San Francisco, CA 94105
In addition EPA conducted a community meeting to discuss the Explanation of
Significant Differences and the onsite construction activities with local residents on
February 20, 1997.
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Support Agency Comments:
The Bay Area Regional Water Quality Control Board concurs with the above changes to
the selected remedy.
Affirmation of Statutory Determination
Considering the new information that has been developed from additional
sampling of the North Parking Lot and the changes that have been made to the
selected remedy, the U.S. EPA believes that the remedy remains protective of human
health and the environment, complies with Federal and State requirements that are
applicable or relevant and appropriate to this remedial action, and is cost-effective.
Keith A. Takata
Director
Superfund Division
SIGNED MARCH 14, 1997
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APPENDIX 1
FACILITIES APPROVED
UNDER
EPA'S OFF-SITE RULE
(Proposed by WESTINGHOUSE)
Aptus, Inc. 1600 N. Aptus Road (site) 801- 531- 4200
(incinerator) Aragonite, UT 84029 (Fax) 801-531-4394
(PCB > 500ppm)
U.S. Pollution Control, Inc. Grayback Mountain 801 323-8900
TSCA (PCB 50ppm - 500 ppm) P. O. Box 22750Fax 801 323-8990
Salt Lake City, UT 84122
Laidlaw Environmental Services 2500 West Lokern Road 805 762-7372
CAD980675276 Buttonwillow, CA 93206
RCRA Subtitle C TSD
(PCB 25 ppm - 50 ppm)
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North Parking Lot
I I
AMERICAN AVE.-M
J
-Reservoir 1
KIFER ROAD
~--~
Reservoir 2
SOIL REMEDIATION
AREA
3OO
Building constructed
between 1906 - 1940
Building constructed
between 1941 - 1949
Building constructed
between 1950 - 1958
Westinghousc Superlund Site
Soils Remediation Comp.2tion Report
SITE PLAN
FIGURS 1 March. 1996
ALTA Goosciences, Inc.
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