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Congressional District # 5


EPA ID# WID988590261
Last Updated: May, 2015

Site Description

The Cedar Creek Site is located in the city and township of Cedarburg (Ozaukee County) in southeastern Wisconsin in a suburban residential area north of Milwaukee. The Cedar Creek site originally included Mercury Marine's Plant 2, the Amcast Industrial facility and associated potential migration pathways to Cedar Creek, and the segment of Cedar Creek from below the Ruck Pond dam to the point where it meets the Milwaukee River. However, the U.S. Environmental Protection Agency (EPA) subsequently listed the Amcast facility on the National Priorities List (NPL) and it is being addressed as a separate site. The Cedar Creek site has not been listed on the NPL but is being addressed using the Superfund Alternative Approach. 

The creek portion of the Cedar Creek Site includes open stretches of creek as well as areas known as Columbia Pond, Wire and Nail Pond, and the former Hamilton Pond, for a total of 4.6 creek miles.

Site Responsibility

The Site is being adressed through federal and potentially responsible party (PRP) actions.

Threats and Contaminants

The main constituents of concern at the site are polychlorinated biphenyls (PCBs). During the early 1980s, the Wisconsin Department of Natural Resources (WDNR) detected PCBs in Hamilton Pond sediment. This prompted additional studies that led to the discovery of PCBs in sediments of three other impoundments on Cedar Creek - namely, Ruck, Columbia, and Wire and Nail Ponds. PCBs from two local companies (Mercury Marine and Amcast Industrial) contaminated Cedar Creek, the Mercury Marine Plant 2 property, the Amcast facility (which is now being addressed as a separate NPL site), and nearby surrounding areas (Quarry Pond, residential yards, Wilshire Pond, sewers).   

Cleanup Progress

Under a State-lead project, Mercury Marine performed a sediment removal action in Ruck Pond, the uppermost impoundment of Cedar Creek with PCB-contaminated sediment. In 2000, Mercury Marine also performed a soil removal action along the Former Hamilton Pond.

In 2002, EPA took the lead on the project. Following discussions between Mercury Marine, Amcast, and EPA, two separate Administrative Orders on Consent (AOCs) were signed. A September 2002 AOC with Mercury Marine required them to perform a Remedial Investigation/Feasibility Study (RI/FS) for the portion of Cedar Creek from just below the Ruck Pond dam to the confluence of the creek with the Milwaukee River, as well as for Mercury Marine's Plant 2 property and related discharge areas in the City of Cedarburg. A February 2003 AOC with Amcast required them to conduct an RI for the Amcast facility and related discharge areas located in the vicinity of the Former Hamilton Pond. The AOCs contemplated that the FS conducted by Mercury Marine would address all areas of the site, including the Amcast facility. However, Amcast filed for bankruptcy in November 2004 before the RI for the Amcast facility was completed. 

The Mercury Marine Plant 2 building was demolished in May 2005.

EPA decided to split the Cedar Creek Site project into operable units (OUs) as described below.  

OU1 - Plant 2

OU1 of the Cedar Creek Site consists of the Mercury Marine Plant 2 property. The Plant 2 RI/FS was completed in October 2007. EPA signed the OU1 Record of Decision (ROD) on March 31, 2008. The selected remedy will serve as the final action for soil contamination at the site. The selected remedy called for excavating soil that exceeds site-specific cleanup levels for PCBs, and excavating shallow soils where the highest VOC concentrations were detected. The remedy also included removal of affected soils around the perimeter and beneath the existing concrete building slab, as well as periodic groundwater monitoring, installation of new monitoring wells, and institutional controls. The final remedy for groundwater will be determined at a later date, based on the results of the periodic monitoring.

In September 2008, Mercury Marine signed an AOC with EPA to conduct the remedial design work required by the March 2008 ROD for OU1. The remedial design was approved by EPA in February 2012. 

In June 2012, EPA began negotiations with Mercury Marine for the remedial action work, and a consent decree between EPA and Mercury Marine was signed in September 2012 and entered by the court in November 2012. Mercury Marine started the remedial action cleanup work in the Fall of 2012 and completed the on-site work in late 2013.   

OU2 - Creek 

OU2 of the Cedar Creek Site consists of Cedar Creek from just below the Ruck Pond dam to the confluence of the creek with the Milwaukee River. The RI Report for OU2 was approved by EPA in May 2012. EPA, WDNR and the PRP have been discussing removal actions.  An EE/CA for a NTCRA will be completed in June 2015.  The Action Memorandum will be proposed in July 2015.  Some cleanup work might begin in the Fall of 2015.    

Amcast Facility (No Longer Part of the Cedar Creek Site)

As discussed above, Amcast filed for bankruptcy in November 2004. Subsequently, EPA decided to list the Amcast facility on the NPL so it would be eligible for federal cleanup funds. The Amcast facility is no longer being addressed as part of the Cedar Creek site. For more information about the Amcast facility, please see the NPL fact sheet for the Amcast site.    

Community Involvement

There is a community group that is involved with the project. 

EPA conducted a public meeting for the proposed plan for the OU1 Plant 2 property in October 2007. 

Property Reuse

The selected remedy for the OU1 Plant 2 property should help facilitate redevelopment of the property.    


Remedial Project Manager, U.S. EPA
scott hansen (hansen.scott@epa.gov)
(312) 886-1999



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