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National Information |
Site Information |
National Priorities List (NPL) HistoryNon-NPL Site Removal Only |
Superfund Program
Twins Inn
|
Site Type: Non-NPL
Status, Removal Only Site City: Arvada County: Jefferson County EPA ID#: CO0001101476 Site Aliases: Thoro Products Congressional District(s): 7 |
Site Description
The Twins Inn Site is located in both the City of Arvada and unincorporated Jefferson County, about 10 miles northwest of downtown Denver, Colorado. The Site area includes a few residences and commercial/industrial businesses which primarily use municipal water supplies. One of the businesses in the area is the Twins Inn Tavern from which the Site derives its name.
In 1995, EPA discovered that the well at the Twins Inn
Tavern was contaminated with a chlorinated solvent called trichloroethene (TCE)
as well as other organic chemicals in excess of drinking water standards. In
response, EPA sampled domestic wells, monitoring wells, groundwater, surface
water, and some soil in the vicinity near the well. EPA traced the source area
to the Thoro Products Co. property at 6611 West 58th Place. Thoro Products Co.
was a small family-owned business that manufactured laundry spot removal, janitorial
supplies, and cleaning products. Thoro Products Co. also acted as a distributor
of bulk chemicals for various companies, including Dow Chemical Co. and others,
and conducted solvent recycling and drum washing operations for a few years.
Operations on this property resulted in the soil and ground water being contaminated
with chlorinated solvents and other chemicals in the area. The ground water
contaminant plume from this site originates near W. 58th Ave. and Nolan St.
in the City of Arvada. It extends east-southeastward almost to Sheridan Blvd.
The plume generally runs parallel to Ralston Creek.
Site Risk
Currently, there is little risk to individuals being exposed to the contaminated soils on-site because the contamination is mainly below the ground surface. Based on earlier indoor air sampling, breathing indoor air at area residences situated directly over the plume does not pose an unacceptable risk to human health. However, indoor air sampling has not yet been conducted in commercial buildings overlying the highest groundwater concentrations levels. EPA's proposed remedy anticipates future air monitoring and mitigation efforts where necessary.
Domestic use of untreated ground water for drinking, cooking,
and bathing would pose an unacceptable risk to human health. Within the area
of the plume, there are only two residences and a local tavern that use a well
as a source for drinking, cooking and bathing. That well has been fitted with
special carbon filters that treat and remove the contamination before it is
used/consumed by the residents and/or the customers of the local tavern. Therefore,
there is no risk to the users of that well.
Cleanup Progress
In 1995, EPA provided bottled water and then installed a water treatment system for the two impacted residences and the Twins Inn Tavern. Annual water sampling is performed to see that the water treatment system is working properly.
EPA conducted field investigations, and numerous Site sampling efforts to understand the source and extent of the ground water contamination and the source of the contamination.
In the Summer of 2008, it was determined that it would be both more cost-effective and time-efficient for EPA to proceed at the Site using its Removal Authority, rather than with its Remedial Authority. The Remedial Investigation/ Feasibility Study (the "RI/FS") was renamed an Engineering Evaluation/Cost Analysis (the "EE/CA") following public notice and a comment period and written rresponse was made to all comments received. The renaming of this document indicates EPA's intent to move forward at this Site using a Removal Action rather than a Remedial Action.
The EE/CA for the Site recommended source removal in combination
with Monitored Natural Attenuation (the "MNA"). At the time of the
publication of the EE/CA, known residential use of the ground water from the
Twins Inn well existed at the Site. Accordingly, the alternatives evaluated
in the EE/CA included this residential risk element. The Site Remedial Action
Plan presented at the public meeting involved a) removal of the contaminated
soil sources located on the Thoro property and b) monitoring the natural attentuation
of the contaminants in the Site ground water.
Community Involvement
Community involvement efforts at this Site include fact sheets, public notices and public meetings. Fact sheets are used to elaborate on Site Documents and to provide definitions and background information on technical terms. Public notices inform the public where records are kept in the different communities.EPA and Colorado Department of Public Health and Environment (the "CDPHE") held a public meeting on May 21, 2007 to discuss cleanup alternatives. The Comment Period for the Proposed Cleanup Plan was extended thirty days to July 5th, 2007. In June 2008, following written responses to all comments received, the Remedial Investigation/ Feasibility Study was renamed an EE/CA following a public notice and comment period. Written responses were made to all comments received.
Site Documents
Twins Inn Fact Sheet (PDF, 10 pages, 246 kB)Feasibility Study Text (PDF, 122 pages, 578 kB)
Feasibility Study Tables 2-2 Through 10-1 (PDF, 46 pages, 463 kB)
Contacts
EPA
Erna Waterman
Remedial Project Manager
U.S. EPA Region 8 (EPR-SR)
1595 Wynkoop Street
Denver, CO 80202-1129
303-312-6762
1-800-227-8917 x6762 (Region 8 only)
email: waterman.erna@epa.gov
Patricia Courtney
Community Involvement Coordinator
U.S. EPA Region 8
1595 Wynkoop Street
Denver, CO 80202-1129
303-312-6631
800-227-7917 x6631 (Region 8 only)
email: courtney.patricia@epa.gov
Colorado
Martin O'Grady
Project Manager
Colorado Department of Public Health and Environment
4300 Cherry Creek Drive South
Denver CO 80246-1530
email: martin.ogrady@state.co.us
