PB96-963106
EPA/ESD/R01-96/127
September 1996
EPA Superfund
Explanation of Significant Difference
for the Record of Decision:
Commencement Bay, Nearshore/Tideflats
Operable Unit 2, Pierce County, WA
7/2/1996
-------
EXPLANATION OF SIGNIFICANT DIFFERENCE
TO THE ASARCO TACOMA SMELTER FACILITY
RECORD OF DECISION
RUSTON AND TACOMA, WASHINGTON
A. Introduct ion
1. Site name and location: Former Asarco Tacoma Smelter
Facility and Slag Peninsula (the "Site"), Operable Unit
2 of the Commencement Bay Nearshore Tideflats Superfund
Site, Ruston and Tacoma, Washington.
2. Lead Agency: U.S. Environmental Protection Agency
(EPA) .
3. Support Agency: State of Washington, Department of
Ecology.
4. Legal authorities for cleanup action: The
Comprehensive Environmental Response, Compensation, and
Liability Act, .as amended (CERCLA), 42 U.S.C. ยง 9601,
et seq., and the National Oil and Hazardous Substance
Pollution Contingency Plan (NCP), 40 C.F.R. Part 300.
B. Summary of Site History. Contamination Problems, and
Selected Remedy
ASARCO, Inc. (Asarco) has owned and/or operated the Asarco
Tacoma Smelter property since 1905. Asarco used the property
initially as a lead smelter and refinery, and converted it in
1912 into a facility to smelt and refine copper from copper-
bearing ores and concentrates shipped in from other locations.
Slag, a black, rock-like, by-product of Asarco's copper smelting
operations was either used by Asarco as a fill to extend the
shoreline of the Site or sold to local entities and companies for
their use as fill. Asarco closed the Smelter in 1985.
Past smelter operations and emissions resulted in releases
of hazardous substances, including arsenic and other heavy
metals, at and in areas surrounding the smelter. Metals that are
in the slag or soil have migrated to surface and ground water at
the Site. Ores which were smelted at the Site left metals in the
buildings and structures on the Site, most of which were removed
pursuant to the Asarco Demolition Consent Decree in May 1992.
EPA issued the Record of Decision (ROD) for the.final
remediation of the Site in March 1995. EPA determined that
cleanup actions were necessary because current conditions on the
Site posed unacceptable risks over the long-term to future
residents, potential workers, and visitors and to the ground
water discharging to Commencement Bay.
-------
One critical component of the ROD is construction of a RCRA-
compliant On-Site Containment Facility (OCF). Pursuant to the
ROD, the OCF will contain the Site's RCRA characteristic source
area soils, granular fill and demolition debris. The OCF's
liner, cap, leak detection, collection and removal system,
leachate collection and removal system and surface run-on and
run-off control systems are required to meet federal and state
standards for a hazardous waste landfill. The ROD states that
the OCF shall be constructed "northeast of the arsenic kitchen
area." ROD, Section 9 .1". 2 (a).
C. Summary of the Explanation of Significant Difference to the
Asarco Tacoma Smelter Facility Record of Decision
EPA has selected a new, on-site location for the OCF after
extensive review and exploration of the original OCF location
identified in the ROD. Asarco, with EPA approval, investigated
subsurface conditions of the proposed OCF location between May
and July, 1995. The investigation revealed that the OCF location
identified in the ROD was unacceptable in its existing state.
Data from the investigation showed the proposed OCF location
was underlain by a buried alluvial valley, partially filled with
loose sands and silts, and partially by soft clay and peat. The
investigation revealed that the sandy and silty materials are
likely to liquify in the event of a severe seismic event,
resulting in slope spreading and settlement. In addition, the
side slopes of the buried alluvial valley appear to be rather
steep, and differential settlement could cause severe local
deformation and stress to liners and collection systems.
Furthermore, clayey and silty alluvial deposits may result in
excessive settlement under the load of the OCF or bearing
capacity failure. Bearing capacity failure would cause large
shear strains that would severely damage the OCF.
Due to the high seismic risk of the area, and the excessive
risk posed by potential bearing capacity failure, settlement and
slope spreading, EPA determined, that further geotechnical
investigation was required to find an alternative OCF location.
Asarco performed additional field investigation and laboratory
testing in the parking lot area of the site, off Bennett Street,
in September 1995. Preliminary analysis indicated that this area
was geotechnically acceptable, and not subject to bearing
failure, excessive settlement or slope instability. As a result,
EPA has selected this area as the new location for the OCF.
D. Public Participation Activities
EPA held two public comment periods from September 20, 1995,
to November 20, 1995 on moving and changing the location of the
OCF from northeast of the arsenic kitchen area to the parking lot
area off Bennett Street (see Superfund Fact Sheets included as
-------
Attachments 1 and 2). The attached Fact Sheets were distributed
to the Asarco mailing list of approximately 800 individuals. In
addition, the Fact Sheets were made available for public review
at the information repositories listed on the back page of the
Fact Sheets (see Attachments 1 and 2). EPA and Asarco also
sponsored community meetings where the geotechnical information
and relocation of the OCF were discussed. EPA did not receive
any' written comments in response to the public comment periods,
and participants at the community meetings did support changing
the OCF's location based on Asarco's findings.
E. Administrative Record
This BSD, the attached Fact Sheets, the Record of Decision,
the Asarco geotechnical reports and other reports and information
related to the Asarco Tacoma Smelter Site are part of the
administrative record for the Site. The administrative record is
.available for public review at the following locations:
1. In.Seattle: Environmental Protection Agency
1200 Sixth Ave.
2. In Tacoma: Tacoma Public Library
Main Branch
1102 Tacoma Avenue South
Northwest Room
F. Affirmation of Statutory Determinations
Considering the new information that has developed and the
change that has been made to the selected remedy, EPA believes
that the remedy remains protective of human health and the
environment, complies with federal and state requirements that
were identified in the ROD as applicable or relevant and
appropriate to this remedial action, and is cost-effective. In
addition, the remedy continues to utilize permanent solutions and
alternative treatment technologies to the maximum extent
possible, as described in more detail in the Declaration of the
Record of Decision, page v.
^
Randall F".' Smith
Director, Office of Environmental Cleanup
-------
Citizens for a Healthy Bay
771 Broadway
Pacific Lutheran University Library
121st and South Park Avenue
In Rustorr
Ruston Town Hall
5117 Winnifred
In Olympia:
Washington Department of Ecology
300 Desmond Drive SE
In Seattle:
Environmental Protection Agency
1200 Sixth Avenue
Questions?
If you have questions or would like more information, please feel free to contact one of
the following EPA representatives toll free in Seattle at 1 (800)424-4EPA, or as indicated
below:
Piper Peterson Lee
Project Manager
(206)553-4951
Jeanne O'DeU
Community Relations Coordinator
(206)553-6919
For those with impaired hearing or speech, please contact EPA's telecommunication
device for the deaf ODD) at (206)553-1698.
To ensure effective communication with everyone, additional services can be made
available to persons with disabilities by contacting one of the numbers listed above.
o
-------
N
N. 51st. St.
Arsenic,
Kitchen
Area
RUSTON
Proposed
OCF
Location
Asarco
Smelter
Site
\
Proposed QCF Location
-------
&EFA
United States Region 10 (HW-117)
Environmental Protection . 1200 Sixth Avenue
Agency Seattle WA 98101
Superfund Fact Sheet
Former Asarco Smelter Site
-------
Region 10
1200 Sixth Avenue
Seattle WA 98101
Alaska
Idaho
Oregon
Washington
September 20, 1995
Superfund Fact Sheet
Former Asarco Smelter Site
Ruston and Tacoma, Washington
Update on Negotiations Between the U.S. Environmental Protection Agency (EPA) and Asarco
on the Former Smelter Site
EPA and Asarco began negotiations on the
cleanup plan in August 1995. The plan
includes cleaning up contaminated soil,
slag, and surface water, including disposal
of highly contaminated soil, without
treatment, in an on-site containment
facility (OCF) on the former Asarco Smelter
site.
One requirement for constructing the OCF
was to determine that it was safe in the
event of an earthquake. Seismic test
results revealed that the location identified
is not safe and another location must be
found. The current plan would put the
OCF on top of an ancient riverbed filled
with sands, silt, clay, peat and slag.
Settling could cause the OCF to sink,
damaging the liners and the safety
detection measures. And In a severe
earthquake, the ground under the OCF
could liquify, settle and shift, causing
severe damage to the structure.
Asarco is currently evaluating alternate
locations for the OCF. Asarco is collecting
information about the ground beneath the
parking lot area to determine whether It
would be a suitable location. If it is not
other areas will be evaluated.
EPA will be taking comments through
October 20, 1995, on any concerns or
questions you may have about moving the
OCF. Please send your comments to Piper
Peterson Lee. EPA Remedial Project
Manager, 1200 Sixth Avenue - MS/HW-
113. Seattle. Washington 98101.
Changing the OCF location may open up
some interesting new public benefits
without compromising the master land use
plan that the public helped develop during
the Asarco Weeks held in 1994. An Asarco
Week will be held in mid-October to discuss
the changes and get public comment.
Asarco will notify community members of
that meeting.
More Information
The Remedial Design Reports (RDRs) that
Asarco is submitting to EPA are being
added to the information repositories for
your review and comment. The first and
second batch of RDRs are available. The
third batch, entitled infrastructure and
transportation, will be available on
September 27th. It describes the process
to determine how the utilities, roadways,
and other elements of future land use will
be tied into the cleanup activities. It also
describes the process to determine the
timing of road closures and other
transportation issues.
What's Next
EPA and Asarco will complete negotiations
that includes an alternate location for the
OCF. Once an agreement on the proposed
Consent Decree and Statement of Work
have been reached, another 30-day public
comment period will be offered.
-------
Questions?
If you have questions or would like more information, please feel free to contact one of the
following EPA representatives toll free In Seattle at 1(800)424-4EPA, or as indicated below:
Piper Peterson Lee
Project Manager
(206)553-4951
Jeanne O'Oett
Community Relations Coordinator
(206)553-6919
For those with impaired hearing or speech, please contact EPA's telecommunication device
for the deaf fTDD) at (206)553-1698.
To ensure effective communication with everyone, additional services can be made available
to persons with disabilities by contacting one of the numbers listed above.
United States
Environmental Protection
Agency
Region 10 (HW-117)
1200 Sixth Avenue
Seattle WA 98101
Superfund Fact Sheet
Former Asarco Smelter Site
------- |