The Superfund program of the US Environmental Protection Agency was created in the 1980s to address human-health and environmental risks posed by abandoned or uncontrolled hazardous-waste sites. This report examines the extent to which various sources contribute to environmental lead contamination at Superfund sites that are near lead-mining areas and focuses on sources that contribute to lead contamination at sites near the Southeast Missouri Lead Mining District. It also recommends potential improvements in approaches used for assessing sources of lead contamination at or near Superfund sites.