HRA assisted clients with research on the Tri-State Mining District, a Superfund site in Kansas, Missouri, and Oklahoma where extensive lead mining activity occurred from the early 1900s to the 1980s. HRA’s work helped determine allocation of cleanup costs at the site.

Using an extensive number of documents collected from the EPA’s Region 7 archives as well as from local and state record repositories, HRA historians prepared a detailed report that included a listing and assessment of the leading mining companies that had contributed to the contamination, and helped determine the current viability of each entity and the respective percentage contribution of waste deposition.