Canonsburg Uranium Tailings Site, Pennsylvania

A processing facility handling radium, uranium and other ores operated here, in western Pennsylvania, from 1911 to 1957. Radioactive contamination at the site was addressed in the 1980s, and the materials were isolated in a pentagonal disposal cell, and capped with erosion-resistant layers, topped by soil which is vegetated to help keep the layer in place. Groundwater monitoring of the surrounding area will continue indefinitely.