East Troy Contaminated Aquifer

Overview

The East Troy Contaminated Aquifer is a Superfund site in Troy, Ohio, added to the National Priorities List in September 2008. It sits in Miami County and is also known as the Troy VOC Plume Site and Troy Well Field. The site is in active remedial action, with construction not yet complete and human exposure not currently under control.

The two main contaminants are tetrachloroethene and trichloroethene, both volatile organic compounds (VOCs) from industrial degreasing operations. These chemicals are present in groundwater, soil, and soil gas across the site. They pose health risks to people who drink contaminated water or breathe vapors that rise through soil and enter buildings through foundation cracks, a process called vapor intrusion. EPA determined that contamination levels pose an unacceptable risk to human health and the environment.

The EPA and Ohio EPA have managed cleanup since 2006, when elevated VOC levels were first detected seeping into buildings. In 2007, EPA installed vapor abatement systems in 16 homes and an elementary school. A remedial investigation finished in 2015, and a feasibility study followed in 2017. EPA finalized an interim cleanup plan in September 2018 targeting two contaminated source areas. For the East Water Street area, crews began excavating contaminated soil during the week of January 26, 2026, with work scheduled to finish by summer 2026. Excavated material was classified as F001 hazardous waste, requiring special handling and disposal procedures. EPA is coordinating with Ohio EPA to meet all waste management requirements. For the Residential Plume Source area, the plan uses in-place chemical oxidation and sub-slab depressurization systems. A groundwater pilot study using permanganate is set to begin in spring 2026. After these interim actions are assessed, EPA will develop a final cleanup decision for remaining groundwater contamination across the entire site.

The remedial design phase has been ongoing since April 2021, with completion estimated between January and March 2028. An additional phase of remedial action is estimated to begin between August and October 2028. EPA does not yet have sufficient data to determine whether contaminated groundwater movement has been stabilized. The site currently hosts four businesses employing 21 people and generating roughly $12.4 million in annual sales.

Community members can review site documents at the Troy Local History Library at 100 West Main Street in Troy, Ohio, phone 937-335-4082. A public meeting was held in May 2025. For questions, contact the EPA Community Involvement Coordinator or Remedial Project Manager.