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Ohio EPA to Update Public on Mentor Marsh Remediation Project

Ohio EPA and the City of Mentor will hold a meeting Tuesday, April 26, 2022, at 6 p.m., in the Mentor Municipal Center, 8500 Civic Center Boulevard, to update the public on the Mentor Marsh Salt Fill remediation project. 

Ohio EPA is working with an environmental contractor to remediate the legacy contamination at the Mentor Marsh. The site, known as the Osborne Salt Fill, has been a source of chlorides that have impacted the marsh and caused water quality issues and altered natural vegetation. The goal of this project is to remove material and return the site to a stable, more natural condition. This project is a result of work by Ohio EPA, the City of Mentor, Ohio Department of Natural Resources, the Cleveland Museum of Natural History, Lake County Health Department, and many others.

Mentor Marsh was made a National Natural Landmark in 1966, and fill activities began shortly after. The first environmental study of salt contamination in the Marsh was in 1970. In 1971, the Marsh was dedicated as Ohio’s First Nature Preserve.

Three prior attempts, dating back to 1972, were conducted to address salt leaching, by placing fly ash over the salt fill, culverting, and relocating Blackbrook Creek.

Ohio EPA and the Ohio Attorney General signed a Consent Order with Osborne Company and the estate of John Osborne in 2019. The Order allocated $10.6 million to remediate the salt fill and required the land be donated to the Lake County Land Reutilization Corporation. The intent is to transfer the land to the Cleveland Museum of Natural History following remediation.



The Ohio Environmental Protection Agency was created in 1972 to consolidate efforts to protect and improve air quality, water quality and waste management in Ohio. Since then, air pollutants dropped by as much as 90 percent; large rivers meeting standards improved from 21 percent to 89 percent; and hundreds of polluting, open dumps were replaced with engineered landfills and an increased emphasis on waste reduction and recycling.