Officially called perfluoroalkyl and polyfluoroalkyl substances, the group of chemicals had been used to manufacture everything from Teflon and Scotchgard water repellent to firefighting foam.
Early research suggests PFAS compounds may be linked to developmental and behavioral problems for infants and children, hormonal problems and even certain cancers.
A growing number of military veterans and others who believe they were exposed to PFAS are wondering if the chemicals triggered their health problems.
Two of the most prevalent types of PFAS are called PFOA (perfluorooctanoic acid) and PFOS (perfluorooctane sulfonate), but there are thousands of different compounds.
The EPA has set a lifetime health advisory for PFOA and PFOS at 70 parts per trillion, but federal research recently made public suggests exposure could be harmful at much lower levels.
At some Michigan sites, officials have detected PFAS levels below the EPA threshold.
In Parchment, known as the “Paper City” because of the shuttered paper mill that long operated there, Lt. Gov.
Brian Calley on Sunday declared a state of emergency after a test detected PFAS at more than 20-times the EPA health advisory level.
The list of contaminated sites is likely to grow as Michigan continues to test all public water systems and schools that tap well water for the chemicals — a process it kicked off in May.
PFAS may have been used or disposed of at as many as 11,300 fire stations, landfills, airports, military sites and other locations, according to a Michigan Department of Environmental Quality presentation first reported by the Detroit Free Press.