A manufactured gas plant operated at 107 South Seventh Street in Fairfield, Iowa from 1878 to 1950. It left behind coal tar sludge, iron oxide wastes, and other byproducts in underground structures on a 1.3-acre property. Coal tar compounds were detected in soil and groundwater in 1985, and the site was added to the National Priorities List (NPL), the federal Superfund program's roster of priority cleanup sites, in August 1990.
Contaminants at the site include polyaromatic hydrocarbons (PAHs), benzene, toluene, ethylbenzene, xylene, naphthalene, arsenic, barium, cadmium, chromium, cyanide, lead, mercury, and selenium. These have been found in soil, groundwater, surface water, and sediment. The primary health risks come from direct contact with contaminated soil and groundwater. Current assessments show human exposure is under control, with no unacceptable pathways for people to reach harmful contamination levels.
Major cleanup actions began with a 1989 settlement agreement. Contaminated soil was excavated and incinerated off-site in 1995. About 1,900 gallons of dense non-aqueous phase liquid, a type of heavy subsurface contamination common at coal tar sites, were removed from the aquifer. A groundwater extraction and treatment system ran until 2001, when it was shut down due to low pumping capacity. Physical construction of the cleanup was completed in August 1995, and the site reached sitewide ready for anticipated reuse status in June 2006.
Groundwater contaminant concentrations still exceed the cleanup levels set in 1990. A Focused Feasibility Study began in May 2021 to evaluate additional remedial options. An Environmental Covenant was recorded with Jefferson County in May 2021 to limit certain activities and land uses on the property. The June 2022 Five-Year Review found the current remedy protects human health and the environment in the short term but concluded that additional alternatives must be evaluated for long-term protection. The next five-year review is estimated between June and August 2027. The site has not been deleted from the NPL.
Community members with questions can contact the EPA's Community Involvement Coordinator or the Remedial Project Manager. For state-related questions, contact the Iowa Department of Natural Resources.
