New Carlisle Landfill

Overview

The New Carlisle Landfill is a 22-acre former solid waste facility in rural Clark County, Ohio, near the city of New Carlisle. It accepted industrial, commercial, and residential waste from the mid-1950s until closing in 1977. The site was added to the National Priorities List (NPL) in April 2009 after vinyl chloride was found migrating toward residential wells within one-half mile. The landfill is covered by a vegetated clay cap two to four feet thick but was never built with a protective liner.

Eight contaminants of concern have been identified at the site. Soil gas contains 1,2,4-trimethylbenzene, 1,2-dichloroethane, 1,4-dichlorobenzene, and ethylbenzene. Groundwater beneath and south of the landfill contains vinyl chloride, cis-1,2-dichloroethene, tetrachloroethene (PCE), and trichloroethene (TCE). Residents and workers can be exposed to these volatile organic compounds (VOCs) through inhalation of soil vapor and indoor air. Human exposure is currently under control, but groundwater migration has not yet stabilized.

Cleanup is organized into two operable units (OUs). OU1 covers the landfill and on-site groundwater. The EPA finalized the OU1 cleanup plan in September 2021. That remedy includes improving the landfill cap, installing gas vents, treating groundwater with microorganisms and zero-valent iron, and installing vapor prevention systems in nearby buildings. Remedial design began in July 2023 and is expected to finish between March and May 2027, when construction will start. The first phase of construction is estimated to run from March through December 2027. OU2 covers off-site contaminated groundwater. A separate groundwater investigation started in 2010 and is still ongoing, with no cleanup decision yet made for that unit.

In 2005, before the site reached the NPL, EPA found VOCs in groundwater south of the landfill and provided alternate water supplies to affected private wells and a nearby tree nursery. The public water supply wells for New Carlisle are 1.7 miles away and upgradient of the site, so they are not affected. The site currently poses no public health hazard to nearby residents and workers, though physical construction of the cleanup is not yet complete and the site is not ready for full reuse.

The EPA released an updated Community Involvement Plan in February 2025 to help residents understand site activities and engage with cleanup efforts. The plan was developed using community interviews held in October 2024. Residents with questions can contact the EPA's Community Involvement Coordinator or Remedial Project Manager.