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Congressional District # 03


EPA ID# WID980820054
Last Updated: March, 2012

Site Description

The Eau Claire Municipal Well Field (ECMWF) 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 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).  The U.S. Environmental Protection Agency (EPA) later determined that the nearby National Presto Industries (NPI) Superfund site was the source of the groundwater contamination at the ECMWF site.

Site Responsibility

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

Threats and Contaminants

Groundwater at the Eau Claire Municipal Well Field site is contaminated with chlorinated VOCs, including trichloroethene, dichloroethene, and tetrachloroethene.  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, implemented remedial actions at the site prevents human exposure to contaminants in the groundwater.

Cleanup Progress

As presented above, 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 concerns both the ECMWF and the NPI sites:

EPA proposed the Eau Claire Municipal Well Field (ECMWF) site for listing on the National Priorities List (NPL) on September 8, 1983, and then placed it on the NPL on September 21, 1984.  Also in 1984, EPA completed a focused Feasibility Study (FS) at the ECMWF site.  On June 10, 1985, EPA issued a Record of Decision (ROD) to select a cleanup remedy for the site, selecting air stripping as an Interim Remedial Measure to address groundwater contamination at the municipal well field.

EPA proposed the NPI site for listing on the NPL on October 15, 1984, and then placed it on the NPL on June 10, 1986.

On September 24, 1985, EPA issued an Action Memo for removal actions at the ECMWF Site.  In 1987, under contract with the EPA, the U.S. Army Corps of Engineers completed construction of an air stripper to treat contaminated groundwater at the site.

On June 6, 1986, EPA and NPI entered into an Administrative Order on Consent (AOC) to conduct a Remedial Investigation/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.

On March 31, 1988, EPA issued a record of decision (ROD) which provided for continued operation of the two-column air stripper that was constructed in 1987 at the ECMWF site.  EPA also required that people on private wells be connected to the municipal water system and for the installation of additional extraction wells in the North Field and in Plume 2 with direct discharge of pumped groundwater into the Chippewa River.  

On April 25, 1989, EPA issued an Unilateral Administrative Order (UAO) to NPI to conduct a Phased FS to find an alternative water source for Hallie, Wisconsin, and required implementation of a bottled water program for all private well users in unincorporated areas affected by Plumes 3, 4 and 5.  On August 1, 1990, EPA issued a second ROD for the NPI site to  select a permanent alternative drinking water supply for the area affected by groundwater Plumes 3, 4, and 5.  This work included construction of a water supply system and an extension of the municipal water service to areas annexed by the city of Eua Claire.  A permanent alternate drinking water supply was installed by NPI in fall 1991 at approximately 174 residences serving a population of 425.

On September 25, 1990, the AOC for RI/FS was modified.

On March 8, 1991, EPA issued a Unilateral Administrative Order (UAO) for Remedial Action  to implement the August 1990 ROD.  This involved the extension of municipal water in Eau Claire, construction of well field, closure and abandonment of all private wells is the area. 

In September 1991, EPA issued a ROD for the selected interim remedial action for on-site contaminated water at the NPI Site.

On July 2, 1992,  EPA issued a UAO to NPI to conduct and interim RD/RA as described in the 9/30/91 ROD.

On August 19, 1993, a Consent Decree (CD) was issued which requires reimbursement of past response costs for the response action (Air Stripper) at ECMWF and for O & M Costs at ECMWF.

On October 14, 1993, an AOC was entered for performance of time-critical removal Lagoon 1 - removal of floating oil and waste forge compound, and post removal site control.

On October 13, 1994, the existing AOC (dated 10/8/93) was modified- adding non time-critical removal activities at Lagoon 1- characterization, evaluation design and remediation of soil/wastes at Lagoon #1.

The final-site wide ROD was issued by EPA on May 15, 1996 for OU #3 ath the NPI Site.  This involved: (1) installation of soil vapor extraction at the Melby Road Disposal Site; (2) removal of soils/wastes from drainage ditch and dry wells 2 and 5; (3) continued operation of air stripper for Plume 1-2; (4) continued operation of pump and treat for Plumes 3 and 4, (5) long-term ground water monitoring and surface water monitoring in Lake Hallie; (6) long term monitoring of Plume 5; (7) surface water sampling in Lake Hallie and (8) institutional controls.

On September 20, 1996, EPA issued a UAO requiring NPI to implement the selected remedial actions in the 1996 ROD for OU #3 at the NPI Site.

On September 30, 1997, EPA issued an Action Memo for non-time critical removal action at the NPI Site.

The first Five Year Review (5YR) for ECMWF was completed in September 1997.  This review determined that the remedy is protective of human health and the environment.  The air stripper at the ECMWF site continued to operate effectively and currently treats approximately six to seven million gallons of water daily.  The pump and treat systems at the NPI site continue to operate properly as do other operation and maintenance activities at the site. 

On September 30, 1998, EPA issued a UAO to conduct removal actions at the NPI site. The UAO required: (1) design /implementation of soil vapor extraction (SVE) at Lagoon 1 and annex, (2) long term O&M of the SVE at Lagoon #1, and (3) implementation of selected remedy for soils stockpiled by Lagoon 1 annex; (4) monitoring of Lagoon 1; and (5) long-term monitoring of groundwater.

The first 5YR for NPI was completed in September 1998.

The preliminary close-out report documenting completion of remedial construction activities was completed by EPA in September 1999. 

The second 5YR was a consolidated review of the NPI and Eau Claire Municipal Well Field sites and was completed in September 2002. The review determined that the remedies for the sites are protective of human health and the environment in the short term. Several follow-up actions at NPI were recommended to assure continued protectiveness for which include: (1) investigating increase in groundwater contamination in the southwest corner of the site; (2) modifying the groundwater monitoring program; (3) labelling and repairing monitoring wells; (4) repairing landfill cap and revegetating; (5) documenting completion of removals at Lagoon #2 and loading dock; and (6) identifying and implemeting needed deed restrictions. The follow-up actions determined to be appropriate by the second 5YR are either underway or completed.  

The third 5YR for the Eau Claire Municipal Well Field site was completed on July 20, 2007.  The review concluded that the remedy protects human health and the environment in the short term.  The air strippers effectively remove the contaminants from the drinking water used by the city of Eau Claire.  In order for the remedy to be protective in the long-term, effective institutional controls 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 protectiveness: (1) an Institutional Control Study needs to be performed and evaluated at the Site to determine if current institutional controls are protective of human health and the environment; (2) an Institutional Control Plan will be prepared to evaluate institutional controls and implement any necessary follow-up activities; (3) an Explanation of Significant Differences will be prepared as an Administrative Matter since groundwater extraction wells in Plume 2 will not be installed; and (4) a determination will be made if groundwater is used as a drinking water source in 77 parcels of land in the city of Eau Claire and if municipal water is available to these parcels.

An Institutional Controls Study has been submitted by the PRPs.  No additional institutional controls are necessary for the well field.  An Explanation of Significant Differences (ESD) was completed 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 was contacted by the city to begin getting municipal water.

An additional ESD was completed on December 23, 2010 which updated the groundwater cleanup requirements to the Enforcement Standards under NR 140 of the State of Wisconsin regulations.

5YRs for the Site will continue until the remedy allows for unlimited use and unrestricted exposure.  EPA is undertaking the fourth 5YR at the Eau Claire Municipal Well Field site and plans to issue the 5YR report in July 2012.

Community Involvement

The 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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