PIKETON, Ohio — The U.S. Department of Energy submitted its 2025 groundwater monitoring report for the Portsmouth Gaseous Diffusion Plant to the Ohio EPA on Tuesday, confirming that significant chemical and radiological contamination persists across the 3,700-acre site — just two days before SoftBank Group and three cabinet secretaries are scheduled to arrive in Piketon to announce a long-term redevelopment plan for the property.
The report, prepared by Southern Ohio Cleanup Company LLC and dated February 2026, details monitoring data collected throughout the 2025 calendar year from more than 100 wells across 18 contaminated areas at the former uranium enrichment facility.
The findings paint a picture of a site still grappling with a toxic legacy — even as it is being positioned as the centerpiece of a billion-dollar energy infrastructure deal between the United States and Japan.
TCE concentrations climbing at worst locations
The most alarming finding in the report is at the X-701B Former Holding Pond, where one monitoring well, X701-130G, recorded trichloroethene — a known carcinogen commonly called TCE — at 120,000 micrograms per liter. The site’s cleanup goal, according to DOE records for TCE, is five micrograms per liter, meaning the concentration at this single well is 24,000 times higher than the remediation target set for the site.
The reading is also higher than the detections recorded at the same well between 2019 and 2022, when TCE ranged from 46,100 to 73,000 micrograms per liter. Rather than declining, TCE at one of the site’s worst contamination points is trending upward.
Other wells in the X-701B area also showed elevated or increasing levels. Well X701-79G recorded TCE at 507 micrograms per liter, up from 319 in 2024. Two wells — X705-03G and X701-45G — are also trending upward at 34.9 and 39.4 micrograms per liter, respectively. Both readings are roughly seven to eight times the cleanup standard.
The report confirms that four active groundwater plumes consisting primarily of TCE remain at the site, despite years of clean-up and billions of taxpayer dollars.
Contamination reaching surface water
The contamination is not confined to groundwater. TCE was detected at 62.7 micrograms per liter in surface water collected from the East Drainage Ditch — more than 12 times the cleanup goal. TCE is also routinely detected in Little Beaver Creek, which receives groundwater discharge from the site. Residents have long asked federal representatives to place warning signs along Little Beaver Creek to warn residents of the potential radioactive and chemical dangers.
Technetium-99, a radioactive byproduct of uranium enrichment with a half-life of approximately 211,000 years, was detected at levels up to 26.9 picocuries per liter in the East Drainage Ditch and Little Beaver Creek. The DOE downplayed the finding, but the bottom line is this: a radioactive isotope with a half-life of 211,000 years is still showing up in the creeks around the plant. Tc-99 has been found in soils throughout a 6 miles radius around the former gaseous diffusion site.
Uranium above drinking water standards
Uranium was detected above the Ohio EPA drinking water standard of 30 micrograms per liter in groundwater samples collected from X-701B monitoring wells. The report does not specify exact concentrations in the report.
Uranium was also detected in the site’s water supply at up to 1.66 micrograms per liter — below the regulatory limit. No transuranics or technetium-99 were found in the that water supply, according to the report provided to the Ohio EPA.
The DOE noted in their report that groundwater beneath the site is prohibited from use for drinking water and is not hydraulically connected to the Scioto River Valley buried aquifer that serves the surrounding community. That aquifer however, is highly suspectible to contamination, according to state enviromental records.
Chromium, TCE expanding at other locations
At the X-616 Former Chromium Sludge Surface Impoundments, chromium was detected at 917 micrograms per liter in well X616-05G — more than nine times the preliminary remediation goal of 100 micrograms per liter. The report notes that chromium is “routinely detected” above the cleanup goal at this well.
The report also states that TCE has been “slowly increasing” in several X-616 monitoring wells over the past 25 years. In 2024, the DOE identified what it called a potential new TCE plume on the west side of the former surface impoundments. Additional sampling in 2025 led the agency to conclude that a defined plume is not present, though TCE continues to be detected in the wells.
At the X-740 Former Waste Oil Handling Facility, TCE was detected above the cleanup goal in two monitoring wells within the excavation area.
Radiological data carries no enforcement weight
The report includes an unusual caveat regarding its radiological findings. The DOE states that radiological data are collected in accordance with DOE Order 458.1 and are included in the report “as information only.” The 1999 Director’s Final Findings and Orders — the legal framework governing cleanup at the site — states that tasks specific to radiological contamination “are not specifically enforceable under that Order.”
Timing raises questions
The report was submitted to Ohio EPA on Wednesday — the same day the RSVP deadline closed for a Friday announcement at the Piketon site involving SoftBank Group, SB Energy, and three senior members of the Trump cabinet.
The media advisory for Friday’s event states that the announcement involves a “long-term plan” for the redevelopment of the DOE Piketon site. On the same ground, the DOE is reporting TCE at 24,000 times the cleanup goal, uranium above drinking water standards, and technetium-99 in the waterways.
Pike County carries some of the highest cancer and premature death rates in Ohio. A study by world- renown epidemiologist Joseph Mangano found that the county’s premature death rate for residents under 74 was 107% higher than the national average between 2021 and 2023.
The Guardian has previously reported on the contamination crisis at the site for the past four years, including the closure and auction of Zahn’s Corner Middle School after enriched uranium and neptunium-237 were detected inside the building. We also reported on deliberate releases of radioactive gas known as “Midnight Rockets” confirmed by declassified documents and an incident in December in which nearly 14 Notices of Violation tied to hazardous waste at the site briefly appeared on the Ohio EPA’s public portal before being removed within hours.
What’s next
The Southern Ohio Cleanup Company LLC, which assumed responsibility for cleanup activities on October 1, 2025, will continue environmental restoration and monitoring at the site.
Friday’s announcement is scheduled for 12:45 p.m. at Piketon. Speakers include Energy Secretary Chris Wright, Commerce Secretary Howard Lutnick, Interior Secretary Doug Burgum, and SoftBank Chairman and CEO Masayoshi Son. The event is part of the U.S.-Japan Strategic Trade and Investment Agreement.
The full 2025 Groundwater Monitoring Report is available here.
Source: DOE/PPPO/03-1370&D1, 2025 Groundwater Monitoring Report for the Portsmouth Gaseous Diffusion Plant, Piketon, Ohio. Submitted to Ohio EPA on March 18, 2026.