EPA ID# WASFN1002174
EPA Region 10

3rd Congressional District

Other Names:
Last Update: May, 2012

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The Hamilton/Labree Roads Ground Water Contamination Superfund Site (Site) is located near the intersection of Hamilton and Labree Roads, west of Interstate 5, about two miles southwest of the City of Chehalis in southwest Washington State. The Site includes two areas where releases of hazardous wastes are known to have occurred: the Hamilton Road Impacted Area (HRIA) (10 acres) and the S.C. Breen Construction Company (Breen) Property (11 acres). The Site also contains an area where a release is likely to have occurred called the Thurman Berwick Creek Area (west of the HRIA and south of the Breen Property). Contaminated groundwater plumes originating from these areas extend downgradient and west of Labree Road. The HRIA comprises Operable Unit (OU) 1 while the Breen Property, Thurman Berwick Creek Area, and downgradient areas outside of the HRIA comprise OU 2.

The contaminants of potential concern are tetrachloroethene (PCE) and its degradation products trichloroethene (TCE), cis-1,2-dichloroethene (DCE), and vinyl chloride, as well as the chemicals tetrahydrofuron and methylene chloride. Total Petroleum Hydrocarbons (TPHs) are also considered to be a presumptive contaminant of concern until more data is collected across the Site. PCE is the primary or "indicator" contaminant at the Site.

Site Responsibility: This site is being addressed through federal and potentially responsible party actions.

NPL Listing HistoryDates
Proposed Date:05/11/2000
Removed Date:
Withdrawal Date:
Final Date:07/27/2000
Deleted Date:

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Media Affected: Surface water, ground water, soil and sediments
The indicator contaminant, PCE, is found primarily in groundwater, and to a lessor extent in surface water, creek bed/sediment and subsurface soils. In groundwater, contamination occurs in the shallow aquifer located approximately 5 to 50 feet below ground surface (bgs). The shallow aquifer is used as a drinking water source for area residences not served on the City of Chehalis water system. There is a deeper aquifer across the Site which is separated from the shallow aquifer by an aquitard. Historically, there have been no confirmed detections of PCE from private wells thought to be screened in the deeper aquifer.

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Contamination was first identified at the Site in late 1993/early 1994 by the Washington State Department of Health (WDOH). Out of 18 water-supply wells sampled, PCE was detected in 6 of these wells. These 6 wells were screened in the shallow aquifer and contained PCE ranging from 3.3. micrograms per liter (ug/L) to 2,165 ug/L. The drinking water maximum contaminant level (MCL) for PCE, as promulgated by EPA, is 5 ug/L. Affected well owners were notified and were provided with bottled water for drinking, cooking, and bathing purposes.

The Washington State Department of Ecology (Ecology), who first supplied the bottled water, initiated investigations to find the source of the contamination. In 1996, WDOH re-sampled 5 of the 6 PCE-contaminated water supply wells and found that concentrations had increased slightly from those measured earlier. Also in 1996, the Lewis County Public Health and Social Services learned from a confidential source that drums containing solvents were buried on the Breen Property. In response, Ecology initiated a geophysical survey and additional subsurface investigations to locate the buried drums. In August 1999, Ecology entered into an Agreed Order with Breen who contracted for an additional geophysical survey and an additional subsurface investigation. In September 1999, 70 drums, pails and cans were removed from beneath a building (Building B) on the Breen Property. A number of the drums appeared to contain a black, viscous product (sludge) and water, as the groundwater had seeped into the leaking drums. Two of the drums were sampled and were found to contain PCE and its degradation products, as did soil and water sampled from the surrounding excavation area. Approximately 600 tons of PCE and petroleum-contaminated soil were removed and disposed off-site as part of the drum removal cleanup.

In 1998, a second source of contamination was identified in what is now called the Hamilton Road Impacted Area (HRIA). Contamination in the HRIA is the result of an apparent spill or "midnight" dumping of PCE into Berwick Creek which runs along Interstate-5 and North Hamilton Road. Groundwater sampling results indicate that there are two distinct areas of groundwater contamination along a 400-foot reach of Berwick Creek. PCE concentrations potentially indicative of dense non-aqueous phase liquid (DNAPL) in groundwater and subsurface soils. PCE concentrations in groundwater were detected as high as 2,720,000 ug/L which is greater than the solubility limit of PCE. The volume of the release is estimated to be between 100 and 700 gallons.

On July 27, 2000, the Site was added to the EPA National Priorities List (NPL). EPA began a phased removal assessment which included installing soil borings and new groundwater monitoring wells, and collecting subsurface soils and groundwater samples in and near the HRIA to evaluate the extent of impacts to private water-supply systemss. This assessment resulted in the expansion of the City of Chehalis municipal water-supply system to 18 properties (15 residential and 3 commercial) which was completed in 2002.

On October 31, 2001, an Administrative Order on Consent (AOC) was signed between EPA and Breen to conduct additional investigations across the Site with the exception of the HRIA study area. Breen conducted remedial investigations pursuant to the AOC until 2004 when they stopped work and entered into cash-out negotiations with EPA. EPA continued to conduct investigations at the HRIA until 2004 to support completion of an Engineering Evaluation/Cost Analysis (EE/CA) and to evaluate potential alternatives for remediation in the HRIA. A remedy, however, was not chosen for the HRIA at that time in part because EPA wanted to obtain and analyze sampling results collected by Ecology and Breen to determine whether a site-wide cleanup plan could be developed.

In July 2007, EPA conducted targeted groundwater and surface water sampling across the Site to further define groundwater contamination, assess contaminant migration, and to assess potential groundwater-surface water interaction. PCE concentrations in monitoring and private wells were consistent with earlier sample results. Two surface water samples were collected. Concentrations of PCE in surface water ranged from 1.7 ug/L to 3.6 ug/L.

In November 2007, EPA conducted air sampling in, under and around private residences and commercial buildings across the Site to assess potential risks to human health from volatilization of contaminants from groundwater to indoor and ambient air. A total of 34 samples were collected over a 24-hour time period using SUMMA canisters. This limited testing has shown that vapor from the PCE-contaminated shallow aquifer is intruding into some homes and businesses but the estimated health risks are very low.

Finally, in May 2010, EPA measured water levels and assessed the condition of most of the monitoring wells at the Site to better understand the hydrology across the Site.

At this time, EPA has assembled most, if not all, of the data collected from across the Site. Based on analyses of this data, there appears to be several additional areas of contamination on the Breen Property that may be actively contributing to groundwater contamination. In addition, the results of groundwater sampling conducted in the area downgradient of the HRIA and south of the Breen Property indicate the presence of a potential source within or upgradient of the Thurman Berwick Creek Area. These potential sources have not yet been positively identified; therefore, additional investigations and analysis must be conducted in these areas.

There is enough reliable data, however, for EPA to proceed with a cleanup plan of the HRIA at this time. EPA is currently finishing the HRIA Feasibility Study and will soon be drafting the HRIA Proposed Plan. EPA anticipates having the Proposed Plan available for public review and comment in summer 2012, and an Interim Record of Decision finalized by December 2012.

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