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Congressional District # 07


EPA ID# WID006196174
Last Updated: February, 2012

Site Description

The 320-acre National Presto Industries (NPI) site was owned by the United States Government War Assets Administration from the early 1940s until 1947. Government contractors manufactured radar tubes and ordnance chemicals at the facility until 1945.  NPI purchased the property from the federal government in 1947 and manufactured household appliances, outboard motors, and defense-related products. By 1954, operations were entirely defense-related, with NPI manufacturing 105mm and 8-inch artillery shells.  Between 1959 and 1965, NPI engaged in little to no active production at the site.  Production of 8-inch shells was restarted and operated from 1966 to 1971, and the 105mm projectiles were produced from 1966 to 1980.

The NPI site lies almost entirely within the city of Eau Claire and abuts the town of Hallie, Wisconsin, with a combined population of over 60,000. The areas to the south, west, and north are generally residential with some industry and agriculture. 

Site Responsibility

This site is being addressed through potentially responsible parties' (PRP) actions under state and federal oversight.

Threats and Contaminants

The most environmentally significant waste that was generated was forge compound, which was a lubricant used in the forging of 105mm shells. Other contaminants of concern include 1,1,1-trichloroethane (TCA) and trichloroethylene (TCE). W aste water discharged to Lagoon No. 1 contained significant amounts of waste forge compound, resulting in groundwater contamination.  Between 1966 and 1970, waste forge compound was also landfilled at the Melby Road Disposal (MRDS) area and near the east property line of the East Disposal area. 

Dermal contact with and/or ingestion of the above contaminants could cause potential human health risks. 

Cleanup Progress

During the cleanup process at the nearby Eau Claire Municipal Well Field (ECMWF) Superfund site, EPA concluded that the National Presto Industries (NPI) site was the source of groundwater contamination at the ECMWF Site. The information provided below covers both the ECMWF and NPI Sites.

The ECMWF Site was proposed for National Priorities List (NPL) by U.S. EPA on September 8, 1983.

The ECMWF Site was placed on NPL on September 21, 1984 by U.S. EPA.

In 1984, U.S. EPA completed a focused Feasibility Study at the ECMWF Site.  On June 10, 1985, U.S. EPA issued a ROD selecting air stripping for ECMWF Site.  This action was selected as an Interim Remedial Measure to address groundwater contamination at the well field.

In 1987, under contract with U.S. EPA, the U. S. Army Corps of Engineers completed construction of an air stripper to treat contaminated groundwater.  Groundwater is treated by the air stripper before being discharged to the municipal water treatment plant and passed on to municipal users.

EPA proposed the NPI site for listing on the NPL on October 15, 1984 and placed the site on the NPL by U.S. EPA on June 10, 1986.

On June 6, 1986, an Administrative Order on Consent (AOC) was entered between EPA and NPI to conduct a Remedial Investigation/Feasability Study (RI/FS).  Five contaminated groundwater plumes were identified emanating from the NPI Site.  Plumes 1 and 2 from the NPI site are the sources of groundwater contamination at the ECMWF Site.  Lagoon No. 1 and the Melby Road Disposal site (MRDS) were determined to be  the most significant sources of the TCA groundwater contamination. The East Disposal site was found to be the source of the TCE groundwater contamination in Plume 5.

On March 31, 1988, the United States Environmental Protection Agency (U.S. EPA) issued a record of decision (ROD) which provided for continued operation of the two-column air stripper, constructed by U.S. EPA as an initial remedial measure at the ECMWF, for groundwater in Plume 1-2.  The ECMWF is located over two miles from the NPI site.  The 1988 ROD also required other measures such as connection of private wells to the municipal water system.  U.S. EPA also selected installation of additional extraction wells in the North Field and Plume Number 2 for direct discharge into the Chippewa River.

On April 25, 1989, U.S. EPA issued an Unilateral Administrative Order (UAO) to NPI to conduct a Phased FS to find an alternative water source for Hallie and requires implementation of a bottled water program (V-W-89-C-015) for all private well users in unincorporated areas affected by Plumes 3, 4 and 5.

On August 1, 1990, U.S. EPA issued a second ROD at Operable Unit #1, selecting a permanent alternative drinking water supply for the area affected by groundwater Plumes 3, 4, and 5.  This involved the construction of water supply system. 

Subsequently, U.S. EPA issued a Section 106 Unilateral Administrative Order (UAO) in March 1991 to NPI and the National Defense Corporation (NDC), requiring implementation of the activities that were identified in the 1990 ROD. This work included construction of a water supply system and an extension of the municipal water service to areas annexed by the city. A permanent alternate drinking water supply was installed by NPI in fall 1991 at approximately 174 residences that serve a population of 425.

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

In September 1991, U.S. EPA issued a ROD for an interim remedial action for on-site contaminated water at the NPI Site.  This ROD was needed to prevent the offsite movement of contaminant Plumes 1-2 and 3 and to prevent further environmental degradation of the groundwater.  The selected remedy included installation of groundwater extraction wells and treatment of the extracted water by two independent cascade aeration units.

On July 2, 1992, U.S. EPA issued a UAO to NPI to conduct the interim RD/RA as described in the 1991 ROD (V-W-92-C- 156).  Construction activities were completed in February 1994, and the groundwater treatment system began operation in March 1994.  From March 1994 through April 1996, a total of 416 million gallons of water were treated. It is anticipated that an additional 150 to 200 million gallons will be treated annually by the cascade aeration units. 
On August 19, 1993, a Consent Decree (CD) was issued for reimbursement to EPA of past costs for the response action (Air Stripper) and for Operation & Maintenance costs at the ECMWF Site.  

On October 14, 1993, an AOC was entered for performance of time-critical removal at Lagoon 1 - removal of floating oil and waste forge compound, and post removal site control (V-W-93 -C- 209).   This AOC required performance of time-critical/non-time critical onsite removal activities, including (1) time-critical excavation of the waste forge compound from Lagoon No. 1 and the East Disposal site and use of such wastes as a supplemental fuel at a cement kiln, and (2) non-time critical removal actions to characterize, evaluate, design, and remediate soils and soil gas, if contamination remains in Lagoon No. 1 after the completed excavation.

On October 13, 1994, the existing AOC, dated October 1993, was modified, adding non time-critical removal activities at Lagoon 1- characterization, evaluation, design and remediation of soil/wastes at Lagoon #1(V-W-93-C-209).   The waste forge compound excavation from Lagoon No. 1 and the East Disposal site were completed in late 1996. U.S. EPA reviewed and approved an engineering evaluation/cost analysis (EE/CA) and provided oversight on the removal action for the installation of a soil vapor extraction (SVE) system to treat residual contamination in Lagoon No.1. This system began operating in late summer 1997 and continues to operate.

The final ROD for the site (operable Unit #3) was issued on May 15, 1996, which further addressed groundwater contamination impacting the Eau Claire Well Field.  This involved installation of soil vapor extraction (SVE) at MRDS; removal of soils/wastes from drainage ditch and dry wells 2 and 5; continued operation of air stripper for Plume 1-2; continued operation of pump and treat for Plumes 3 and 4; long term monitoring of Plume 5; surface water sampling in Lake Hallie; and institutional controls.

On September 20, 1996, the U.S. EPA issued a UAO requiring NPI to implement cleanup actions in the 1996 ROD (OU #3).

The prefinal remedial design (RD) for an onsite cap and SVE for the Melby Road Disposal site was submitted to U.S. EPA for review and approval in December 1997. Work began in spring 1998. This site will require long-term groundwater treatment, soil vapor extraction, groundwater monitoring, and cap maintenance. Although groundwater currently shows improvement at this time, the treatment will continue for the foreseeable future.

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

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

The first Five Year Review for ECMWF was completed in September 1997. The air stripper at the ECMWF Site continues 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.

The first Five Year Review for the NPI Site was completed in September 1998.  This review recommended continuation of the extraction wells and cascade aerators until final groundwater cleanup levels are achieved. The review also made a determination that the remedy selected remains protective of human health and the environment.

Construction completion for the site was documented in the preliminary close-out report, dated September 1999.  On-going five year reviews are required since the remedy does not allow for unlimited use and unrestricted exposure.

The second five-year review was a consolidated review of the NPI and Eau Claire Municipal Well Field sites (the Sites) and was conducted in September 2002.  The review determined that the remedies for the Sites continue to be protective of human health and the environment.  Several follow-up actions to assure continued protectiveness were recommended which include: investigating increase in groundwater contamination in the southwest corner of the site; modifying the groundwater monitoring program; labelling and repairing monitoring wells; repairing landfill cap and revegetating; documenting completion of removals at Lagoon #2 and loading dock; and identifying and implemeting needed deed restrictions.  The progess on the follow-up actions are as follows:   (1) The southwest corner was investigated and a new source area was discovered.  A soil/vapor extraction system was constructed and is operating.  Extraction well 3 was replaced with extraction well 5 and VOC concentrations measured in the monitoring wells have stablilized or decreased.   (2) NPI submitted draft criteria to modify the groundwater monitoring plan.  U.S. EPA and WDNR commented on the plan and NPI submitted a revised criteria/plan.  The revised plan has been implemented on an interim basis.  (3) Most groundwater monitoring wells have been repaired, labeled and locked as needed.  Some wells are vulnerable to damage because of location.  (4) Repairs and revegetation were performed on the Melby Road Disposal Site cap.  (5) Documentation of the Loading Dock and Lagoon 2 removals were completed for Lagoon 2.  (6) U.S. EPA issued a letter requiring NPI to complete an institutional control study.  NPI has committed to completing the study.

The third five-year review for the NPI site was signed on September 18, 2007.  It determined that the remedial actions at operable units (OUs) 1, 2 and 3 are protective in the short term.  Long term protectiveness for OUs 1, 2 and 3 will be achieved once groundwater clean up standards are met and effective Institutional Controls (ICs) are in place.  Several follow-up actions were recommended which include: (1) NPI submit a workplan to investigate the the reason that VOCs are not decreasing in several monitoring wells in the Southwest Corner of the NPI property; (2) NPI complete an IC study and submit a workplan for implementing ICs; and (3) U.S. EPA oversee the implementation of the IC workplan.  The investigation has begun in the Southwest Corner of the NPI property.  U.S. EPA, in conjunction with the Wisconsin Department of Natural Resources, is working with the PRP on implementing a Restrictive Covenant for this site.  U.S. EPA also approved an 18 month trial shutdown of the extraction wells at the Melby Road Disposal Site to determine if these wells still need to be operated in order to maintain compliance with the groundwater cleanup goals.  An Explanation of Significant Differences was signed in December 2009 which updated the groundwater cleanup goals to the Enforcement Standards to be consistent with the State of Wisconsin regulations.

Five Year Reviews for the NPI Site will continue because the remedy does not allow for unlimited use and unrestricted exposure.  The fourth five year review of the NPI site is due in September 2012.

Community Involvement

Site-related documents are available for review at:

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

Hallie Town Hall
13033 County Highway OO
Chippewa Falls, WI

City of Eau Claire Public Works Dept.
203 S. Farwell St.
Eau Claire, WI

Chippewa Falls Public Library
105 W Central St.
Chippewa Falls, 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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