In the most recent evaluation of monitoring data reported in March 2022, results showed that contaminant levels in the shallow (water table) aquifer were either stable or decreasing. However, in the deeper (intermediate) aquifer, levels of benzene and benzo(a)anthracene were increasing at some locations.
| City | Mason City |
|---|---|
| County | Cerro Gordo County |
| State | Iowa |
| Coordinates | 43.14760, -93.19920 |
Mason City Coal Gasification Plant is a federal Superfund site in Iowa. The Superfund program, created by Congress in 1980, addresses sites where hazardous substances have been released or threaten release into the environment. EPA scores potential sites using the Hazard Ranking System; those that score high enough are placed on the National Priorities List.
Current status: Ready for anticipated reuse. EPA considers this site ready for anticipated reuse, meaning cleanup has progressed enough for certain land uses. This does not necessarily mean all contamination has been removed — institutional controls like deed restrictions may limit how the land can be used.
EPA has identified 10 contaminants of concern at this site, including 1,2-dihydroacenaphthylene, 2-methylnaphthalene, 9h-fluorene. Contamination has been detected in groundwater, soil, sediment, surface water.
If you live near this site and have health concerns, your state health department can provide site-specific guidance. EPA maintains a community involvement program for most NPL sites, and site documents — including the Record of Decision, five-year reviews, and public health assessments — are typically available through EPA's Superfund site profile.