The Wisconsin Department of Natural Resources and the Department of Health Services advised people to eat no more than one meal a month of rainbow smelt from Lake Superior in January 2021. The advisory followed the discovery of high levels of per- and polyfluoroalkyl substances, persistent contaminants known as “forever chemicals.”
Michigan’s health department issued a similar warning in 2022.
PFAS are manmade chemicals that have been used in numerous industrial and consumer products for decades, including firefighting foam, which was used on a series of fires at a Superior oil refinery in 2018, causing elevated levels of PFAS in a creek that flows into Lake Superior.
In early 2020, samples for perfluorooctane sulfonate — the specific substance of concern detected in rainbow smelt — continued to average around 40 times higher than normal in the creek.
The substance has been linked to illnesses including cancer, fertility issues and developmental problems.
Wisconsin Department of Natural Resources: New smelt consumption advisory for Lake Superior
Lake Superior Reserve: Analysis of PFAS release following the April 2018 refinery fire in Superior, Wisconsin