The Site is located at 605 and 607 East Maple Street in Maquoketa, Jackson County, Iowa. Consisting of a former industrial site in a mixed-use area of residential, agricultural, and commercial land, the Site encompasses three Jackson County parcels and approximately 10.86 acres of land. The Site is bounded to the north by East Maple Street, with commercial and industrial properties beyond; to the east by a metal barn/residence (at a former railroad grade) and a farm center; to the south by residential properties and farmland; and to the west by South Clark Street, with residential properties beyond. The Clinton Engines Museum is on the northwestern portion of the former manufacturing facility. Beginning in approximately 1945, the Site hosted industrial operations, which included the production of small engines manufacturing facility for lawnmowers, chainsaws, outboard boat engines and related parts. The Clinton Engines Company acquired the property in 1950 from the Maquoketa Company and continued the production of small engines. The facility included a foundry, machine shops, cast and painting operations, and underground storage tanks (UST). The Clinton Engines Company officially closed in 1999, and the Site was donated to the City of Maquoketa in 2000. The facility had several interconnected factory buildings and a separate office/administration building. The majority of the buildings were severely dilapidated with collapsed walls, rubble, fallen-in roofs, and broken windows. Multiple unknown USTs, including a buried railroad tanker car were reported to be at the Site. Following donation of the Site to the City of Maquoketa, all of the former facility buildings were removed with exception of the former office/administration building and the USTs were located and removed by 2004. In 2004, the area with the old office/administration building was parceled-off and sold to the Jackson County Historical Society (JCHS), which restored the building into the Clinton Engines Museum. The remaining land is owned by the City of Maquoketa and is vacant land, which was leased to the JCHS with intentions to plant natural prairie vegetation for bee and butterfly pollination. Multiple buildings associated with the Clinton Engines Museum have since been constructed. In March 2005, the Contaminated Sites Section of the Iowa Department of Natural Resources (IDNR) received a Phase I Environmental Site Assessment (ESA) and Phase II ESA regarding the Site dated October 15, 1999. The 1999 Phase I ESA indicated the following significant observations: (1) the machine shop, shipping and receiving, and one paint booth was in active use; (2) other portions of the Site were described as dilapidated, with holes in the roof and walls and standing water; (3) observed apparent USTs, chemical storage rooms, and 55-gallon drums throughout the Site. The 1999 Phase II ESA identified concentrations of chlorinated volatile organic compounds (VOCs), as well as fuel-related VOCs in groundwater and soil that exceeded a regulatory benchmark. In May, 2005, IDNR notified the City of Maquoketa of the transfer of the Site to the Contaminated Sites Section within IDNR. In June 2005, an Initial Site Screening (ISS) was completed and specified the need for additional investigations. In 2006, additional Site investigation activities occurred, according to the Voluntary Land Recycling Program (LRP) enrollment application, and reported elevated concentrations of chlorinated and fuel-related VOCs in groundwater. In addition, the Voluntary LRP enrollment application included information pertaining to the removal of three additional USTs at the Site (two 20,000-gallon diesel tanks and one 8,000-gallon tank of unidentified contents) from 2001 to 2002. In April 2008, the Site was enrolled in the Voluntary LRP. In 2013, the sampling of groundwater monitoring wells installed as part of previous investigations occurred. Elevated concentrations of chlorinated and fuel-related VOCs were c