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Congressional District # 07


EPA ID# WID006196174
Last Updated: March, 2015

Site Description

The 320-acre National Presto Industries (NPI) site lies almost entirely within the city of Eau Claire and abuts the town of Hallie, Wisconsin, with combined populations of over 60,000. Areas to the south, west, and north of the site are generally residential with some industry and agriculture. Site features include Waste Lagoon No. 1, the East Disposal site, and the Melby Road Disposal site (MRDS).

The 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. Waste products from the plant have contaminated soil and groundwater beneath the site.

EPA proposed to place the NPI site on the National Priorities List (NPL) in October 1984 and listed the site on the NPL in June 1986.

Site Responsibility

The NPI site is being addressed through potentially responsible party (PRP) actions under state and federal oversight.

Threats and Contaminants

The most environmentally significant waste that NPI 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). Waste water that was 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 NPI site was the source of groundwater contamination at the ECMWF site. The information provided below covers both the ECMWF and NPI sites. 

In 1984, EPA completed a focused Feasibility Study at the ECMWF site and in June 1985, EPA issued an interim Record of Decision (ROD) that selected air stripping to address groundwater contamination at the well field. In 1987, under contract with 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 distributed to municipal users.

On June 6, 1986, an Administrative Order on Consent (AOC) was entered by EPA and NPI to conduct a Remedial Investigation/Feasability Study (RI/FS) at the NPI site, which is located over two miles from the ECMWF site. Five plumes of contaminated groundwater were found to be emanating from the NPI Site. Plumes "1" and "2" 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 TCA groundwater contamination at the NPI site. The East Disposal site was found to be the source of the TCE groundwater contamination in Plume "5."

On March 31, 1988, EPA issued a ROD for the NPI site that provided for continued operation of the two-column air stripper, which was constructed by EPA as an initial remedial measure at the ECMWF, for groundwater in Plumes 1 and 2. The 1988 ROD also required other measures such as connection of private wells to the municipal water system. EPA also selected installation of additional extraction wells in the North Field and Plume 2 with direct discharge of extracted groundwater into the Chippewa River.

On April 25, 1989, EPA issued an Unilateral Administrative Order (UAO) to NPI to conduct a Phased FS to fund an alternative water source for the town of Hallie 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, 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, EPA issued a 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 served a population of 425.

In September 1991, EPA issued a ROD for an interim remedial action to address on-site contaminated water at the NPI site. This ROD was needed to prevent the off-site movement of contaminant Plumes 1, 2, and 3 and to prevent further degradation of groundwater quality. 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, EPA issued a UAO to NPI to conduct the interim RD/RA as described in the 1991 ROD. 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 was 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 entered that provided for  NPI's 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. 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 1 after the completed excavation.

On October 13, 1994, the 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.  The waste forge compound excavation from Lagoon 1 and the East Disposal site were completed in late 1996. 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 1. This system began operating in late summer 1997 and continues to operate.

EPA issued the final ROD for the site (Operable Unit #3) 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 Plumes 1 and 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 placement of institutional controls on the properties.

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

The prefinal remedial design (RD) for an on-site cap and SVE for the MRDS was submitted to 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, EPA issued an Action Memorandum for a non-time critical removal action at the NPI site.

On September 30, 1998, 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. 

EPA completed the first Five Year Review (FYR) of the NPI Site cleanup remedy in September 1998. The FYR report recommended continuation of the extraction wells and cascade aerators until final groundwater cleanup levels are achieved. EPA also made a determination that the selected remedy 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 FYRs are required since the remedy does not allow for unlimited use and unrestricted exposure.

The second FYR was conducted as a consolidated review of the NPI and Eau Claire Municipal Well Field sites and was completed in September 2002. The FYR report 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 included: investigating an 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 the loading dock; and identifying and implemeting needed deed restrictions.

The progress on the follow-up actions was 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. 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 MRDS cap; (5) Documentation of the Loading Dock and Lagoon 2 removals were completed for Lagoon 2; and, (6) EPA issued a letter requiring NPI to complete an institutional control (IC) study and NPI later committed to completing the IC study.

The third FYR report 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 should 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 should complete an IC study and submit a workplan for implementing ICs; and (3) EPA should oversee the implementation of the IC workplan. The investigation was begun in the Southwest Corner of the NPI property. EPA, in conjunction with WDNR, worked with the PRP on implementing a Restrictive Covenant for this site. EPA also approved an 18-month trial shutdown of the extraction wells at the MRDS to determine if these wells still need to be operated in order to maintain compliance with the groundwater cleanup goals. 

EPA issued an Explanation of Significant Differences in December 2009 that updated the groundwater cleanup goals to Enforcement Standards under Wisconsin regulations.

The fourth FYR report for the NPI site was signed on September 4, 2012. EPA considers the site-wide remedy to be protective in the short term because the remedial actions have been fully implemented and are operating as intended. Effective ICs have been implemented and are being maintained as well. There is no evidence of current human exposure to site contaminants. Long-term protectiveness will be achieved when groundwater on and from the NPI site attains cleanup standards.

EPA will complete the fifth FYR report by September 2017.

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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