The North Ridge Estates Superfund site is a residential subdivision located approximately 3 miles north of Klamath Falls, Oregon. The site is contaminated with asbestos as a result of the improper demolition of approximately eighty 1940s-era military barracks buildings. OU1 encompasses the footprint of the former Marine Recuperation Barracks, constructed during World War II and includes approximately 125 acres. Asbestos-containing material was used in construction of most of the Marine Recuperation Barracks buildings. Cement asbestos board was used on exterior walls as siding and on interior walls as wainscoting, asphalt-asbestos roofing material, vinyl asbestos tile, floor tile mastic, and steam pipe insulation. The primary contaminant of concern at OU1 is asbestos. In addition, arsenic contamination is present above background in soils at the OU1 former power plant location.
The remedy for OU1 was identified in a 2011 Record of Decision and included excavation of contamination to a minimum of 2 feet and maximum of 4 feet below ground surface across the entire area of OU1. The excavated area was to be backfilled with a minimum of a 2-foot clean soil cap or pavement and driveways/sidewalks restored to the previous conditions. The contaminated soil was to be consolidated within two repositories to be capped and seeded. Long-term operations and maintenance of the repository covers will be required and deed restrictions will be placed on the excavated properties.
EA provided construction oversight during the remedial action, conducted over three construction seasons from May 2016 through December 2018. EA completed submittal reviews for changes and provided recommendations to EPA, including on constructability and cost reasonableness. During construction, EA maximized the use of local subcontractors, employed members of the community, and locally sourced equipment to reduce the project’s carbon footprint. EA supported relocation of residents during the remedial action, prepared materials for public meetings, and presented material at meetings as directed by EPA. Over the course of the construction, 340,000 cubic yards was excavated from 54 properties and consolidated into the repositories. The completion of the project in Fall 2018 included placement of the final covers on the two repositories and replacement of the subdivision roadways.