(PFAS or PFASs) a group of synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain; there are 7 million such chemicals according to PubChem.

This timeline of events related to per- and polyfluoroalkyl substances (PFASs) includes events related to the discovery, development, manufacture, marketing, uses, concerns, litigation, regulation, and legislation, involving the human-made PFASs.