A 3-acre former manufactured gas plant currently owned by Alliant Energy that was in operation from 1878-1950, during which time the plant utilized a coal gas process that generated coal tar sludge, iron oxide wastes, and other coal gasification wastes. In 1950, the production system was converted to natural gas, which was then discontinued in 1988. Contamination related to coal gas operations, primarily the storage of waste by-products stored in below ground containment structures was first discovered in a 1986 study, and subsequent investigations were conducted to evaluate the extent and nature of the contamination. The site was enrolled in the National Priorities List in the late 1980s, and in the 1990s, the main source areas of contamination along with contaminated soil were excavated and disposed of. Following removal actions, a groundwater pump and treat system was installed to treat on-site groundwater, and groundwater monitoring was conducted. The pump and treat system was shut down in 2001 due to an apparent lack of effectiveness on remediating the groundwater and alternative remedial actions have been and currently are being evaluated, and continued groundwater and vapor intrusion monitoring are currently under way to ensure that human health and the environment off site continues to be protected. The site is currently being evaluated for additional alternative remedial actions and monitoring continues to monitor groundwater plume stability and to ensure that the groundwater plume is not migrating off site.