The cleanup of Tri-State Mining District lands was divided for EPA purposes into a total of four National Priority List (NPL) Superfund Sites: the Cherokee County Site, Cherokee County, Kansas; the Orongo-Duenweg Site, Jasper County, Missouri; the Newton County Mine Tailings Site, Newton County, Missouri; and the Tar Creek Site, Ottawa County, Oklahoma. The Cherokee County Superfund Site was in turn divided into seven subsites that were grouped and divided into nine operable units (OUs). The area around Treece was designated OU4. Thus, while Treece is located less than a mile north of Picher, Oklahoma, a town which was closed due to lead pollution, Treece was located at a different Superfund site. Picher's residents' property was bought out by the Environmental Protection Agency. Residents of Treece also demanded a buy-out, but at first were not certain of receiving one.