From 1964 to 1989, Marion Pressure Treating Company used creosote to treat wood products on a 22-acre property in Marion, Louisiana. Creosote is a hazardous substance made up of polycyclic aromatic hydrocarbons (PAHs) and dense non-aqueous phase liquids (DNAPLs), which are oily contaminants that sink through soil and groundwater. The site was added to the National Priorities List (NPL), the federal list of priority Superfund cleanup sites, in February 2000.
EPA has identified 42 contaminants of concern at the site. These include PAHs such as naphthalene, anthracene, pyrene, fluoranthene, and phenanthrene, as well as metals like arsenic and thallium, and the volatile organic compound benzene. Contaminants appear in groundwater, soil, and sediment. Health risks include carcinogenic hazards from contact with PAHs in Big Creek sediments and from ingesting or absorbing arsenic and thallium through groundwater. Non-carcinogenic risks come from arsenic, barium, and manganese in crayfish tissue and from several groundwater contaminants. Human exposure is currently under control, but groundwater migration is not yet under control.
EPA began removing contaminated material in September 1996, excavating about 10,000 cubic yards of soil and placing it in a capped on-site consolidation area. A Record of Decision in June 2002 set the original cleanup plan, and a Record of Decision Amendment in September 2016 revised it. The updated plan calls for capping improvements, deep soil mixing with solidification and stabilization where free-phase creosote is present, sediment consolidation near Big Creek, and long-term groundwater monitoring. EPA also removed 49 waste piles and sealed them in an on-site repository with an impervious liner. Deep soil mixing solidified the DNAPL contamination to stop it from spreading toward drinking water sources.
Remedial action ran from October 2004 through September 2010. A second design phase ran from August 2018 to May 2021, and final remedial action began in August 2022. On-site construction was completed in September 2025, according to the community summary. Separately, the cleanup progress summary states construction has not yet been completed, with an estimated finish between September and November 2026. Both claims appear in the source materials. The site is estimated to be ready for anticipated reuse between July and September 2027, with a five-year review estimated for February through April 2028.
Community members can review site records at Marion City Hall, 398 Main Street, Marion, Louisiana 71260, by calling 318-292-4715, or at the Louisiana Department of Environmental Quality (LDEQ) office at 602 N 5th Street, Baton Rouge, Louisiana 70802. EPA updated its Community Involvement Plan in April 2015. For questions, residents can contact the EPA Community Involvement Coordinator or the Remedial Project Manager.
