CHILLICOTHE, Ohio — Arsenic in groundwater beneath the former Mead Industrial Landfill on South Paint Street has risen to more than three times the federal safety limit and is trending upward with each sampling event, according to laboratory results and Ohio EPA records obtained by The Fallout Files.
The most recent data — from a semi-annual sampling event conducted May 18-19, 2026, by Langan Engineering and Environmental Services — shows arsenic at monitoring well P23-40 reached 31.4 micrograms per liter, up from 28.3 six months earlier. Monitoring well P13-42 recorded 21.3, up from 20.9. A duplicate sample taken simultaneously from P13-42 returned 21.1, confirming the reading was not a laboratory anomaly. The federal Maximum Contaminant Level for arsenic in drinking water is 10 micrograms per liter. The worst well is now 3.14 times that threshold — and climbing.
The contamination is neither new nor confined to arsenic. A total manganese isoconcentration map prepared by Langan for the first half of 2023 shows manganese contamination extending well beyond the landfill boundary to the west, south, and northeast, with the 50 micrograms per liter isoconcentration line — the EPA’s Secondary Maximum Contaminant Level — reaching into wooded areas and land adjacent to residential properties. The May 2026 lab results confirm the pattern persists. Five monitoring wells exceeded the EPA’s Lifetime Health Advisory Level of 300 micrograms per liter for manganese: P12-30R at 751, P11-52 at 572, P20-50 at 474, P9-45R at 438, and P15-35 at 316. Eleven of 16 sampled wells returned manganese concentrations above the 50-microgram-per-liter secondary standard.
The EPA classifies arsenic as a known human carcinogen. Long-term exposure has been linked to cancers of the bladder, lung, skin, kidney, liver, and prostate, as well as cardiovascular disease. The federal health goal for arsenic — the Maximum Contaminant Level Goal — is zero, because no level of exposure is considered free of cancer risk. The 10 microgram per liter MCL is a regulatory compromise based on treatment cost and feasibility, not a declaration of safety. Long-term manganese exposure above the 300 microgram per liter health advisory level can cause manganism, a neurological condition that mimics Parkinson’s disease, according to the EPA. Infants, adults over 50, and individuals with liver disease face the highest risk.
The site, located just off South Paint Street, operated as a solid waste landfill for the Mead Corporation. The facility has changed hands through a series of corporate transactions. The most recent Ohio EPA compliance letter references Smurfit Westrock. An Ohio EPA interoffice memo dated August 4, 2026, references a post-closure care certification report submitted by MW Custom Papers, LLC. Laboratory reports from the May 2026 sampling event are addressed to WestRock. The landfill has been under long-term corrective measures monitoring governed by an approved Corrective Measures Plan dating to January 2002.
The August 4, 2026, interoffice memo documents a June 30, 2026, inspection of the facility. According to the memo, the landfill cap appeared intact and well-vegetated, with no significant erosion or slope instability observed. The leachate management system — consisting of a perimeter toe drain connected to extraction manholes — also appeared to be functioning as designed. Collected leachate is transported off-site for disposal at the U.S. Gloves wastewater treatment plant in Chillicothe, which was formerly operated by Pixelle.
The memo notes that reported leachate production volumes from 2023, 2024, and 2025 “should be considered unreliable due to operational/contractor issues.” Three consecutive years of unreliable leachate data at a facility where carcinogenic arsenic and neurotoxic manganese are migrating through the groundwater.
Ohio EPA instructed WestRock in October 2020 to maintain financial assurance for post-closure care at a minimum of $842,409 “until an agreement is reached regarding the extended post-closure care period.” No reductions to the financial assurance instrument have been approved. The interoffice memo concludes that the evaluation “does not take into account all the relevant information to reliably anticipate whether the owner/operator/permittee is eligible to end post-closure care.”
The May 2026 sampling event also included the first known PFAS sample from the landfill’s leachate system. Field notes document the sample was collected from the site’s second leachate manhole. The leachate sample returned arsenic at 1.12 micrograms per liter and manganese at 95.3 — nearly double the EPA’s secondary standard. The PFAS analytical results, if they confirm the presence of per- and polyfluoroalkyl substances, would add a third class of contaminants to an already compromised site. Those results have not been released as of publication.
The monitoring well data from the May 2026 sampling shows arsenic was detected at 15 of the 16 monitoring wells sampled, though most fell below the MCL. Wells P23-40 and P13-42 — the same two flagged in the 2025 compliance letter — remain the only wells exceeding the 10 microgram per liter standard. But the direction of the trend at both is upward, not downward.
The Mead landfill joins a list of southern Ohio sites where legacy contamination persists long after operations ceased. The Fallout Files has documented this pattern across Ross, Pike, Jackson, Pickaway, and Scioto counties: facilities shut down, monitoring continues, contaminants exceed federal thresholds, regulators review the paperwork and find it compliant, and the contamination persists.
The corporate successors to Mead Corporation, through their engineering consultants, continue to submit semi-annual monitoring reports. Ohio EPA continues to review them and find them compliant with applicable rules. The arsenic continues to exceed federal limits and continues to rise. The manganese continues to migrate off-site. The cycle continues.
Editor’s note: The lab report below shows the arsenic result for monitoring well P23-40 as 0.0314 mg/L. At a glance, a number three one-hundredths of a milligram looks negligible. It is not. Converted to the unit used by federal regulators, that reading is 31.4 micrograms per liter — 3.14 times the EPA’s Maximum Contaminant Level for drinking water. The EPA’s MCL itself appears on many documents as 0.010 mg/L rather than 10 µg/L. One milligram per liter equals 1,000 micrograms per liter. The math is simple. The presentation is not. Lab reports are written for scientists and engineers, not for the residents living near a site. When contamination data is expressed in units that make dangerous concentrations look like decimal dust, the public has no intuitive way to gauge the risk.
