3M’s $12.5 billion deal to resolve lawsuits brought by hundreds of water providers is one of the largest settlements to date involving contaminated drinking water, but it is a fraction of its total legal liability involving “forever chemicals.”

The settlement, announced Thursday, resolved a good chunk of the multidistrict litigation against 3M over perfluoralkyl and polyfluoroalkyl substances, or PFAS, found in aqueous film-forming foam that firefighters have used to combat large fires, and linked to cancer and other health problems.