Central Illinois Public Service Co.

Overview

The Central Illinois Public Service Co. site is a former manufactured gas plant in Taylorville, Illinois. It was added to the National Priorities List (NPL), the federal roster of priority Superfund sites, on August 30, 1990. Cleanup has been underway for decades, and while major construction work finished in September 1995, the site remains on the NPL and continues to require active management.

The site has 44 confirmed contaminants of concern found in groundwater, soil, or both. These include polycyclic aromatic hydrocarbons (PAHs) such as benzo[a]pyrene and naphthalene, volatile organic compounds (VOCs) including benzene, toluene, and xylene, and phthalates. The EPA determined these substances pose an unacceptable risk to human health and the environment based on the amounts present, how people and ecosystems could come into contact with them, and the health effects that could follow.

Ameren, the responsible party, has carried out cleanup work under a Consent Decree executed in March 1994. Early work included excavating roughly 12,000 cubic yards of contaminated soil and sediments starting in January 1987. About 20 residents received a permanent alternate water supply, and their private drinking water wells were properly abandoned. A pump-and-treat system has been running since 1995 to pull contaminated groundwater to the surface and clean it. That system works, but it would take an estimated 100 years or more to meet Illinois Groundwater Quality Standards on its own. To speed things up, Illinois EPA and Ameren are evaluating in situ solidification and stabilization (ISS) as the preferred next step. ISS mixes binding agents directly into contaminated soil using large augers, locking contaminants in place. A focused feasibility study was completed in June 2023, and a Record of Decision Amendment was issued in July 2023 to reflect this direction.

The site does not present an immediate threat to human health right now. Institutional controls are in place to prevent groundwater use until drinking water standards are met. The EPA has confirmed that human exposure is under control and that groundwater is not discharging to surface water at unacceptable levels. The site was declared sitewide ready for anticipated reuse in September 2012. Five-year reviews continue, with the most recent completed in July 2024.

Community members can follow progress through EPA and Ameren project documents. Site records are available at the Taylorville Public Library at 121 W. Vine St., Taylorville, IL 62568, reachable at 217-824-4736. The EPA's Community Involvement Coordinator and Remedial Project Manager handle questions directly.