Varying federal and state definitions of PFAS, and whether those definitions include refrigerants, are creating regulatory uncertainty for industry, experts say, especially as more states weigh bans on PFAS-containing refrigerants amid ongoing hurdles toward implementing alternatives to such refrigerants. Maine and Minnesota, for example, define per- and polyfluoroalkyl substances (PFAS) to include substances “with at least one fully fluorinated carbon atom.” These would include trifluoroacetic acid (TFA), the PFAS often produced by refrigerants like hydrofluorocarbons (HFCs) and hydrofluoroolefins (HFOs). These...