The Michigan Department of Environmental Quality is advising people to avoid swallowing the foam that appears on top of the water in the Rogue River near Rockford, Michigan.
The foam is highly contaminated with PFAS, an emerging group of chemicals linked to reproductive, developmental, liver, and kidney problems.
The agency says PFAS is not easily absorbed through the skin, so contact with the water is OK. But children who might accidentally ingest the foam should be kept from face contact with the water, or swimming.
The PFAS contamination likely comes from the former Wolverine Worldwide tannery in Rockford. The tannery has also contaminated the groundwater in town with PFAS.