National Zinc Corp.

Overview

The National Zinc Company ran a zinc smelter at this site from 1907 to 1976, processing zinc, cadmium, and lead. That operation left heavy metal contamination across nearby residential areas in Bartlesville, Oklahoma. The site is currently proposed for the National Priorities List, which is EPA's roster of the most serious uncontrolled hazardous waste sites in the country.

EPA has identified nine contaminants of concern here. Arsenic and lead are present in soil in areas that pose human health risks. Cadmium, lead, selenium, and zinc appear in soil and sediment in ecological areas of the site. Cadmium is also found in sediment in those ecological areas.

Cleanup is organized into two main operable units. The first covers human health areas and uses excavation, engineered caps, onsite containment, offsite disposal, institutional controls, and monitoring. The second covers ecological areas and applies solidification and stabilization, excavation, onsite containment, and monitored natural recovery. EPA implemented a removal action near the smelter in 1992. By September 2001, the Oklahoma Department of Environmental Quality (ODEQ) had completed substantially all remediation work in residential areas, cleaning up roughly 1,000 properties. Five-year remedy reviews in 2001, 2006, 2011, and 2016 all found the cleanup protective of public health. The most recent five-year review was completed in October 2021 under state oversight.

Blood lead testing shows real progress. Studies from 1991 to 1992 found about 14% of children in the affected area west of Bartlesville had elevated blood lead levels above 10 micrograms per deciliter. Follow-up testing from 1995 through 2010 found no elevated levels using that same standard. After the CDC lowered its screening level to 5 micrograms per deciliter in 2012, elevated levels were still not detected in the tested population. EPA has determined that human exposure at the site is currently under control. Construction of the full cleanup is not yet complete, and a combined remedial investigation and feasibility study for human health areas is estimated to run from early 2027 through late 2028.

Institutional controls remain in place, and the City of Bartlesville actively enforces them to keep the site protective of the community. Community members with questions can contact the EPA Community Involvement Coordinator. For remedial project matters, contact the Remedial Project Manager. For state-related questions, contact ODEQ.