Chemours must make major changes to its plan for cleaning up per- and polyfluoroalkyl substances (PFAS) from groundwater near its plant in Fayetteville, North Carolina, the state’s Department of Environmental Quality (DEQ) says. The facility is the source of PFAS, such as hexafluoropropylene oxide dimer acid, that pollute drinking-water supplies for hundreds of thousands of households in southeastern North Carolina, including those connected to water utilities and those with wells. Chemours proposed a cleanup plan to the DEQ at the end of December, as required under a February 2019 legal order with the state. “The proposed plan is clearly deficient,” DEQ secretary Michael S. Regan saysin an April 7 statement. The agency says Chemours’s plan “lacks a thorough technical basis, including an adequate assessment of human exposure to PFAS compounds and a thorough evaluation of on- and off-site groundwater contamination.” In a statement provided to C&EN, Chemours says its plan is “robust” and that it is “surprised and disappointed” by the DEQ’s announcement. “We look forward to learning the details behind their comments,” the company adds.