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Congressional District # 03


EPA ID# WID980820054
Last Updated: March, 2015

Site Description

The Eau Claire Municipal Well Field (ECMWF) Superfund site is located near the Chippewa River in the city of Eau Claire, Eau Claire County, Wisconsin.  The site consists of 14 municipal water supply wells that provide drinking water to the 57,600 residents of the county. In the mid-1980s, routine groundwater sampling conducted by the state of Wisconsin indicated elevated levels of volatile organic compounds (VOCs) in the Eau Claire municipal water supply, including trichloroethene (TCE), dichloroethene (DCE), and tetrachloroethene (PCE). EPA later determined that the nearby National Presto Industries (NPI) Superfund site was the source of the groundwater contamination at the ECMWF site.

EPA proposed to add the ECMWF site to the National Priorities List (NPL) in September 1983 and then placed the site on the NPL in September 1984. EPA later proposed the nearby NPI site for listing on the NPL in October 1984 and then placed the NPI site on the NPL in June 1986.

EPA deleted the ECWMF site from the NPL on May 27, 2014.

Site Responsibility

The Eau Claire Municipal Well Field site is being addressed through a combination of potentially responsible party (PRP) and federal and state actions.

Threats and Contaminants

Groundwater at the Eau Claire Municipal Well Field site is contaminated with chlorinated VOCs, including TCE, DCE, and PCE. People could be exposed to these VOCs if they were to drink or come into direct contact with the contaminated groundwater or if they were to inhale the VOCs that the contaminated water may release into the air.  Exposure to these chemicals could cause adverse health effects.

EPA has ruled out that the nearby Chippewa River has been affected by the groundwater contamination, as pumping of the municipal wells prevents area groundwater from discharging into the river. Now, the implemented remedial actions at the site prevent human exposure to contaminants in the groundwater.

Cleanup Progress

Based on site investigative work, EPA concluded that the nearby National Presto Industries (NPI) Superfund site was the source of groundwater contamination at the Eau Claire Municipal Well Field (ECMWF) site. Thus, the information provided below may concern both the ECMWF and the NPI sites. (Please refer to the separate NPI site fact sheet for a thorough discussion of site cleanup activities at the NPI site.)

EPA completed a focused Feasibility Study (FS) at the ECMWF site in 1984 and then issued a Record of Decision (ROD) in June 1985 to select an interim cleanup remedy.  EPA selected air stripping as an Interim Remedial Measure to address groundwater contamination at the municipal well field. In September 1985, EPA issued an Action Memorandum to conduct removal actions at the ECMWF site. In 1987, under contract with the EPA, the U.S. Army Corps of Engineers completed construction of a two-column air stripper to treat contaminated groundwater at the site.

In June 1986, EPA and National Presto Industries ("National Presto") entered into an Administrative Order on Consent (AOC) to conduct a Remedial Investigation and Feasibility Study (RI/FS) at the NPI site. During the RI, EPA identified the NPI site groundwater contaminant "Plume 1" and "Plume 2" as the sources of the groundwater contamination at the ECMWF site. A total of five contaminant plumes were found to be emanating from the NPI site.

In March 1988, EPA issued a ROD for the NPI site that called for the continued operation of the two-column air stripper constructed in 1987 at the ECMWF site. EPA also required that people on private wells be connected to the Eau Claire municipal water system and for the installation of additional extraction wells in the Plume 1 and the Plume 2 groundwater contamination areas, with direct discharge of pumped groundwater into the Chippewa River.

In April 1989, EPA issued a Unilateral Administrative Order (UAO) to National Presto to conduct a Phased FS to find an alternative water source for neaby town of Hallie and to implement a bottled water program for all private well users in unincorporated areas affected by the other three contaminant plumes. In August 1990, EPA issued a second ROD for the NPI site to select a permanent alternative drinking water supply for the area affected by these three plumes. This work would include the construction of a water supply system and an extension of the municipal water service to areas annexed by the city of Eau Claire. 

In March 1991, EPA issued a Unilateral Administrative Order (UAO) to National Presto to implement the August 1990 ROD. This involved the extension of municipal water to affected residences in Eau Claire, construction of a well field, and closure and abandonment of all private wells in the area. The permanent alternate drinking water supply was installed at approximately 174 residences serving a population of 425.

In August 1993, EPA and National Presto entered into a Consent Decree (CD) that required National Presto to reimburse EPA for all past response costs at the ECMWF site and to reimburse Eau Claire for operation and maintenance costs of the air stripper at the municipal wellfield.

EPA completed the first Five Year Review (FYR) at the ECMWF site in September 1997. EPA determined that the remedy was protective of human health and the environment.  The air stripper at the ECMWF site was found to be operating effectively and was treating about 6 to 7 million gallons of water daily.

EPA completed a preliminary close-out report by documenting completion of remedial construction activities at the ECMWF site in September 1999. 

EPA issued a second FYR report for the ECMWF site in September 2002 and consolidated the FYR findings for the NPI site in this report. The review determined that the remedies for both sites were protective of human health and the environment over the short term.  (Several follow-up actions were recommended for the NPI site to assure continued protectiveness, but these actions did not impact the ECMWF site work.  National Presto has completed the recommended actions.)

EPA completed the third FYR report for the ECMWF and NPI sites in July 2007.  The review concluded that the remedies were protective of human health and the environment over the short term. The air stripper was found to effectively remove the VOC contaminants from the drinking water pumped by the city of Eau Claire. The FYR report noted that in order for the (ECMWF site) remedy to be protective over the long-term, effective institutional controls (ICs) must be in-place and maintained until the groundwater cleanup standards are achieved throughout the plume area. Several follow-up items were recommended to assure continued remedy protectiveness: (1) an IC Study should be performed and evaluated at the sites to determine if current ICs are protective of human health and the environment; (2) an IC Plan should be prepared to evaluate existing institutional controls and to implement any necessary additional controls; (3) EPA should issue an Explanation of Significant Differences (ESD) decision document as an administrative matter since groundwater extraction wells in Plume 2 were no longer necessary; and (4) a determination should be made if groundwater is used as a drinking water source in a certain 77 parcels of land in the city of Eau Claire and if municipal water is available to these parcels.

An ICs Study was later submitted by National Presto. Upon review, EPA determined that no additional ICs were necessary for the well field. EPA issued an Explanation of Significant Differences (ESD) was issued on May 29, 2008. The city of Eau Claire completed its review of the 77 parcels of land and found that one parcel was not tied into the municipal water system and the parcel owner was contacted by the city to begin getting municipal water.

EPA issued an ESD on December 23, 2010, which updated the groundwater cleanup requirements to the Enforcement Standards promulgated under NR 140 of the Wisconsin Administrative Code.

The fourth FYR for the ECMWF site was completed on July 17, 2012. EPA, in consultation with the Wisconsin Department of Natural Resources (WDNR), determined that the cleanup remedy at the site was protective of human health and the environment because cleanup standards have been met at the site and, in the interim, exposure pathways that could result in unacceptable risk are being controlled through the use of institutional controls. EPA also determined that the air stripper at the ECMWF site can be taken off-line as the groundwater entering the city's well field had met the cleanup standards for over five years and is not expected to exceed the standards in the future.

EPA completed a separate FYR report for the NPI site in September 2012.

EPA completed a Final Close Out Report (FCOR) on April 5, 2013 for the ECMWF site.  The FCOR documented that EPA has completed all response actions at the site and that it anticipates that no further Superfund response is necessary to protect human health and the environment.

EPA deleted the ECWMF site from the NPL on May 27, 2014.

Community Involvement

The ECMWF site five-year reports and other site-related documents are available for review at:

L.E. Phillips Memorial Library
400 Eau Claire St.
Eau Claire, WI


Remedial Project Manager, U.S. EPA
howard caine (caine.howard@epa.gov)
(312) 353-9685

Community Involvement Coordinator, U.S. EPA
susan pastor
(312) 353-1325




Site Profile Information

This profile provides you with information on EPA's cleanup progress at this Superfund site.


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