EPA Superfund site
FORMER UNITED ZINC & ASSOCIATED SMELTERS
Human exposure is NOT currently under control
Data limitations: Proximity to a Superfund site boundary does not mean your property is contaminated. EPA site boundaries show the area designated for cleanup, not the full extent of contamination. Groundwater plumes can extend beyond site boundaries. This tool shows publicly available EPA federal data. It is not affiliated with or endorsed by EPA, and is not a substitute for a professional environmental assessment.
About this site's exposure pathways
As of May 2026, the Former United Zinc & Associated Smelters Superfund site is considered 'Current Human Exposure Not Under Control' because residents and recreational users at their homes, parks and creeks can be exposed through direct contact to arsenic and lead in contaminated soils and sediments. Cleanup levels for lead contamination were set at 400 parts per million (ppm) or greater and arsenic contamination at 35 ppm or greater. This reduces exposure risk for young children to lead and the carcinogenic risk of arsenic below 1 x 10-4 for carcinogenic risk and a non-cancer total hazard index of 1.
The planned activities to address the pathways are a continuation of ongoing removal of soil contaminated with arsenic and lead. Additional actions include implementing health education and institutional controls at a local level. These programs will target the entire community and stakeholders, such as builders or others who disturb soil, informing them of the risks of exposure, methods to prevent exposure, and measures to control the future spread of contamination through education and best management practices. Approved guidance and pamphlets are distributed to the community with information on reducing exposure risk.
EPA has already started cleaning up the contaminated soil. Cleanup actions have resulted in the remediation of 1,238 residential properties. EPA continues working in conjunction with local officials to assist in the health education and institutional control efforts that include the dissemination of relevant information and with future focus to incorporate building permit requirements, in addition to the possible use of deed restrictions and/or environmental covenants for residential properties with contamination left at depth.
In following with the EPA Residential Lead Guidance published in October 2025, the action limits are anticipated to be lowered 200 ppm. With this update to action limits, HEUC is expected to be reached in July 2043.