CHILLICOTHE, Ohio — More than 27 years after Ohio regulators ordered cleanup measures at Chillicothe’s former WearEver manufacturing plant, new groundwater testing shows industrial chemicals remain beneath the property and have migrated beyond its boundaries, with some concentrations far exceeding federal drinking-water standards.
Two reports prepared for Howmet Aerospace and dated Oct. 10, 2026, document continuing contamination involving trichloroethylene, vinyl chloride and other chlorinated solvents, according to the filings. The documents also show that plans to expand the groundwater monitoring network remain delayed because agreements allowing access to neighboring properties have not been finalized.
Testing conducted June 23, 2026, found several chemicals well above the U.S. Environmental Protection Agency’s drinking-water maximum contaminant levels. At monitoring well MW-C-I on the former WearEver property, vinyl chloride measured 230 micrograms per liter, about 115 times the federal standard of 2, and trichloroethylene measured 260 micrograms per liter, 52 times the standard of 5. A second on-site well recorded TCE at 220 micrograms per liter, 44 times the standard, and an off-site well also recorded three contaminants above their federal standards.
The findings arrive as the neighboring former Chillicothe paper mill undergoes major ownership and operational changes, creating uncertainty about the industrial groundwater pumping system that has helped control the direction of the contamination for years. For decades, high-capacity wells at the mill have influenced groundwater movement around the former factory, and the monitoring report identifies Collector Wells 17 and 18, about 2,000 feet east and northeast of the site, as particularly important to the containment strategy.
The June report states that if industrial pumping decreases substantially or stops, groundwater beneath the former WearEver property would likely move east-southeast, generally toward the Scioto River. The report says Collector Well 17 was not operating during the June monitoring event, and it notes that the longer-term pumping plans for the mill property remain uncertain, even as parties involved in the transition have publicly stated the wells will remain operational.
Ohio EPA raised concerns in July 2025 about the consequences of reduced pumping and requested additional monitoring. Howmet negotiated a revised plan for additional wells, but its October 2026 progress report states that access agreements sent to nearby property owners in October 2025 had not been returned with signatures, so installation of the additional wells has not occurred. Howmet says it began enhanced quarterly monitoring in the third quarter of 2025 and will continue it until conditions are better understood.
The reports leave several questions open for Chillicothe and Ross County residents: whether newer sampling changes the picture, when the expanded monitoring wells will be installed, and whether the existing remedy will need to change as the paper mill property is redeveloped. Fourteen additional groundwater samples collected Aug. 19 and 20 were not included in the October filings and are expected in a separate third-quarter monitoring report.