Frequently asked questions

Pentachlorophenol (PCP)

    Pentachlorophenol (PCP) is a man-made chemical which was once one of the most widely used pesticides in the country. PCP was used as a pesticide and wood preservative. PCP is still in use today, but is now a restricted-use pesticide that may only be applied by licensed applicators approved by the State. It is no longer available for sale to or use by the general public.

    PCP is still used today as an industrial wood preservative in things such as utility poles, railroad ties, and wharf pilings, but is being phased out by the EPA.

    PCP was contained within a commercially available wood treatment product that was used at the Wauleco facility. It was known as Woodtox and was manufactured by Koppers Corporation. The Woodtox product was about 5% PCP. The PCP-containing Woodtox material was surface-applied to the wood window products by either dipping or spraying the wood.

    Because the PCP is deep beneath the ground (nearly 30 feet), remedial treatment options for the site are limited. It has been difficult to recover this material from this deep in the ground, but Wauleco has been successful in recovering a lot of it-- and those efforts continue. Wauleco continues to evaluate new technology as it becomes available, in an attempt to remove the remaining product more efficiently.

    The small white sheds you can see on the site are referred to as pump houses. They provide protection from the weather for onsite recovery wells that operate as part of our groundwater recovery and treatment system. Those wells pump water out of the ground some 25 or more feet below the surface, which is then piped to our treatment system. Without those sheds, the electrical controls on the well pumps would be exposed to the elements and may cause operational issues.

    PCP from the Wauleco site is approximately 20–30 feet below the ground. The water you drink and use is supplied by the City of Wausau, and is not impacted by groundwater beneath the Wauleco site.

    The City sewer system that has evidence of cracks are the sewage lines transmitting material to the City’s treatment plant for treatment. This is separate from the water supplied by the City for drinking and other purposes. While evidence suggests that the City's sewer system may have cracks letting water in, Wauleco is working in close collaboration with the City to identify potential openings that could allow PCP dissolved in groundwater to enter. We’re hopeful this can be remedied in the near future.

    Not at this site. PCP is not sufficiently volatile to cause vapor migration, so it isn't a concern. In addition, our investigation has consistently concluded that the soils on our site have enough oxygen that vapor build-up is not a concern, and the DNR agrees. We recently assessed this again—you can read a report of our conclusions and the WDNR's agreement.


    The term “dioxins” generally refers to a certain group of chemicals created inadvertently as a by-product of a number of human activities. These compounds can be created in the course of chemical manufacturing, incomplete combustion, vehicle exhaust, backyard burning, forest fires, and volcanic eruptions. In chemistry, these materials are referred to as chlorinated dibenzo-p-dioxins (CDDs) and chlorinated dibenzofurans (CDFs).

    Yes. Dioxins are ubiquitous in an urban environment and there are many potential sources of dioxin-producing activities in the neighborhood. Expert toxicologists from the State of Wisconsin Department of Health Services studied the sampling results to date and have concluded that there is no apparent health hazard for people using Riverside Park and residents living in the Thomas Street neighborhood. They have also recommended that further sampling be conducted to confirm their conclusions. We understand that the City of Wausau has completed further sampling under the oversight and direction of the WDNR, and that the city has developed a cleanup plan for the former rail corridor.

    Waste wood was previously burned at the Wauleco site to provide heat and steam. Because wood-burning can be a source of dioxins, the WDNR asked Wauleco to look into this and perform additional sampling. Wauleco completed this work and concluded that its historic wood-burning did not result in dioxins in Riverside Park, and the WDNR agreed.

    We’re all exposed to dioxins. Over 90 percent of human exposure to dioxins comes through food—mainly animal products such as dairy, meat, fish, and shellfish. Based on what we know currently, state toxicologists have concluded that the background levels of dioxin they’ve studied in neighborhood soils are not a threat to human health.

    We encourage you to direct further questions about Riverside Park to City of Wausau officials.


    No, PFAs are not a concern at the Wauleco site, and the DNR has confirmed this.