Dover Chemical Corp. sits on 60 acres in Dover, Ohio and has operated as a chemical manufacturing facility since 1950, producing components for lubricants, plasticizers, and flame retardants. EPA proposed the site to the National Priorities List in May 1993. Today, manufacturing continues at the facility while cleanup work addresses contamination left behind by improper chemical storage, spills, and leaks that occurred from the 1950s through the early 1970s.
Nine contaminants of concern have been identified, all found in groundwater in an off-site plume extending about one mile southeast of the site. Those contaminants include benzene, chloroform, trichloroethene, chlorobenzene, and four dichlorobenzene compounds. The cleanup is divided into two main areas. The first covers on-site contamination at the facility, where Dover Chemical operates a pump and treat system to capture and process contaminated groundwater before it discharges to a nearby river, along with soil vapor extraction systems at two locations. The second covers the off-site groundwater plume.
EPA selected a remedy for the off-site plume in September 2015. That remedy combines in-situ chemical oxidation injections near the plume's origin, aerobic amendments along the plume's center line to reduce toxicity, and monitored natural attenuation. A January 2018 Consent Decree committed Dover Chemical to carry out the remedial design and cleanup action for the off-site plume at an estimated cost of $7.4 million. Pilot testing of in-situ chemical oxidation injections ran from June to August 2023, with final monitoring scheduled for June 2025 and an evaluation report due in September 2025. Full remedial action on the groundwater plume is estimated to begin between June and August 2028.
EPA assessments indicate that human exposure is currently under control across the entire site, with no unacceptable exposure pathways identified. Groundwater migration is stabilized, though EPA will continue monitoring to confirm contaminated groundwater stays in its original area. Physical construction of the cleanup is not yet complete, so the site is not yet ready for its anticipated future use. Two businesses currently operating on-site employed 180 people and generated roughly $142 million in annual sales revenue as of December 2024.
Community members who want to review site records can visit the Dover Public Library at 525 N. Walnut St. in Dover, Ohio, or call (330) 343-6123. EPA staff are also available for direct questions.
