The Tulsa County Smelter Complex (TCSC) near Collinsville, Oklahoma includes two zinc smelters, the Bartlesville Zinc Smelter (“BZ Smelter”) and the Tulsa Fuel & Manufacturing Co. Smelter (“TFM Smelter”), as well as where hazardous substances have come to be located, including the area known as the Collinsville Soil Program (“CSP”) Study Area.

In the early 1990s, the Oklahoma Department of Health and the Oklahoma Department of Environmental Quality, in coordination with the US Environmental Protection Agency (US EPA), conducted various sampling and assessment activities at the TFM Smelter. The results of the soil sampling indicated high concentrations of heavy metals arsenic, lead, cadmium, and zinc. The US EPA placed the TFM Facility on the National Priorities List in 1999. Similarly, sampling of properties near the BZ Smelter indicated high levels of heavy metals and the CSP was implemented to address clean up of those properties. Cleanup of the TCSC has been ongoing since 2005. Initially with the TFM Smelter then the BZ Smelter and the CSP program. The CSP program is ongoing.

Lead can have adverse effects on birds and mammals. Zinc is also toxic at high concentrations, though its toxicity depends on its chemical form and other environmental parameters. Terrestrial plants experience adverse effects when exposed to elevated zinc soil levels and can die from excess zinc in the soil, and birds can experience a range of symptoms, including death. As a result of the high concentrations of heavy metals at the TCSC, the natural resource trustees, Cherokee Nation, State of Oklahoma, and the US Department of the Interior, acting through the US Fish and Wildlife Service and Bureau of Indian Affairs, initiated a Natural Resource Damage Assessment and Restoration (NRDAR) case in 2017 under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Natural resources and associated services that may have been injured by exposure to high levels of heavy metals include, but are not limited to, soil, terrestrial animals (including birds and mammals), and culturally significant tribal resource services. The NRDAR case is ongoing.