The Baxter/Union Pacific Tie Treating site is a 140-acre former railroad tie treatment plant in Laramie, Wyoming. It operated from 1886 to 1983, using creosote and pentachlorophenol to preserve wood. Spills over that time contaminated both soil and groundwater. The site was added to the Superfund National Priorities List in September 1983 and deleted in December 1999 after cleanup goals were met. Ongoing oversight continues under RCRA (Resource Conservation and Recovery Act) corrective action, administered by the Wyoming Department of Environmental Quality.
EPA identified 43 contaminants of concern at the site. These include heavy metals such as arsenic, chromium(VI), copper, and zinc, along with organic compounds like benzene, toluene, and creosote. Polycyclic aromatic hydrocarbons, including benzo[a]pyrene, anthracene, and naphthalene, are also present. Dioxins and phenolic compounds round out the contamination picture. Most of these contaminants appear in both soil and groundwater.
The cleanup focused on one main operable unit centered on containment and isolation. Key measures include a vertical slurry wall to contain contamination, a water treatment plant with three extraction wells using pump-and-treat methods, removal of dense oily liquids and contaminated soil and debris, a topsoil cover over low-level contaminated areas, and phytoremediation using native plants. Construction of all cleanup measures was completed in July 2002. Human exposure is under control, and contaminated groundwater migration has stabilized with no unacceptable discharge to surface water. The Wyoming Department of Environmental Quality has determined the final remedy protects human health and the environment. A second operable unit covering oil recovery has not yet received a final decision document. The site is not yet at sitewide ready-for-reuse status, and five-year reviews continue under RCRA.
The site has already seen meaningful community reuse. A greenbelt park with a bike path and walkway opened in 2001, connecting Optimist Park to the site along the Laramie River. A portion of the site remains in industrial use with restricted access. Union Pacific filed a restrictive covenant to prevent groundwater wells on the former Boyd property. Potential risks to wildlife are also monitored as part of ongoing oversight.
Community members with questions can contact the Wyoming Department of Environmental Quality. EPA also accepts inquiries through its Superfund Contact Us form.
