The Kellogg-Deering Well Field supplies about half of Norwalk, Connecticut's public drinking water. Groundwater contamination was discovered in the 1980s beneath a nearby industrial complex. The site was added to the National Priorities List in September 1984. Cleanup has progressed across two operable units, one focused on treating water at the wellhead and one focused on controlling contamination at the source. The site reached sitewide ready for anticipated reuse status in September 2020, and a five-year review completed in September 2022 found the cleanup protective of human health and the environment in the short term.
Contaminants in soil and groundwater include chlorinated solvents such as 1,1,1-trichloroethane, 1,1-dichloroethene, 1,2-dichloroethane, and vinyl chloride. Benzene, toluene, ethylbenzene, xylene, chloroform, and methylene chloride are also present. People could be exposed by drinking untreated water, but treatment systems are in place to prevent that. Air strippers installed in 1981 and 1988 remove volatile organic compounds (VOCs) from drinking water, and VOC levels have met drinking water standards since 1989. A soil vapor extraction system operated from 1994 until it was dismantled in 2006 after soil cleanup standards were met. A groundwater extraction and treatment system continues to run, preventing contaminated groundwater from migrating toward the municipal wells.
Human exposure is currently under control, with no unacceptable exposure pathways identified. Groundwater migration is also under control, with contamination stabilized and no unacceptable discharge to surface water. Monitoring conducted in 2008 to 2009 and again in 2018 to 2020 confirmed that vapor risks from groundwater do not pose unacceptable risks to nearby homes and buildings, though additional monitoring is warranted. The EPA noted that the current groundwater extraction system may not fully restore groundwater within a reasonable timeframe. If the source area is redeveloped, additional steps may be needed to assess soil vapor risks to future occupants.
Institutional controls are legally binding restrictions that stay in place as long as contamination or cleanup equipment remains on site. At this site, Connecticut state law requires permits before any well drilling begins, and a permit cannot be issued unless the proposed well location meets the state public health code. Three businesses currently operate on site. The next five-year review is estimated between September and November 2027.
Community members can review site documents at the Norwalk Public Library at One Belden Avenue, Norwalk, CT, or at the EPA Region 1 records center in Boston. Questions can be directed to EPA's Community Involvement Coordinator, the Remedial Project Managers, or the Connecticut Department of Energy and Environmental Protection.
