Superfund Site Profile


EPA completed a five-year review of the Oconomowoc Electroplating Superfund site. The Superfund law requires regular checkups of sites that have been cleaned up – with waste managed on-site – to make sure the cleanup continues to protect people and the environment. This was the fifth five-year review of this site.

The review concluded that the cleanup is protecting people and the environment.                     

EPA’s original cleanup plan in 1990 included a groundwater extraction system that had been pumping and treating contaminated underground water. That system was shut down in 2004 after an EPA study determined it was ineffective. A 2011 amendment to the cleanup plan included natural processes to treat groundwater contaminants and either source area removal or in-place treatment of the remaining contamination.

The next review is scheduled for 2022.



The Oconomowoc Electroplating Co., Inc. site is located in the unincorporated town of Ashippun, a rural area about 35 miles west of Milwaukee. It operated from 1957 to the early 1980s as an industrial facility that used metals, chemicals and organic compounds in its production process. During that time, the company discharged untreated wastewater into nearby wetlands and Davy Creek. Two unlined lagoons on the property contained electroplating sludge. These lagoons leaked and sometimes overflowed. Contaminants, called volatile organic compounds, or VOCs, made their way into the groundwater beneath and downstream of the site.