Worst Superfund Sites in America

There are over 1,300 sites on EPA's National Priorities List — the federal government's roster of the most seriously contaminated places in the country. But even among Superfund sites, some stand out. The sites listed below are those where cleanup is actively underway: contamination severe enough to require ongoing remediation, not just monitoring or institutional controls.

"Cleanup underway" means EPA has approved a remediation plan and work is in progress. These sites may involve groundwater pump-and-treat systems, soil excavation, containment walls, or other engineering controls. Some have been in active cleanup for decades. The number of identified contaminants of concern gives a rough sense of complexity — sites with many contaminants across multiple media (soil, groundwater, sediment) tend to require longer, more expensive remediation.