PTFE is the slippery plastic coating best known by the brand name Teflon. It is a PFAS polymer — a long chain of carbon-fluorine bonds — which makes it extremely durable and non-stick.

An intact PTFE coating is generally considered stable at normal cooking temperatures. The main concerns are the chemicals historically used to manufacture it (like PFOA, phased out in 2013) and fumes released if a pan is overheated above roughly 260 °C / 500 °F.

Because PTFE never breaks down in the environment, scientists still classify it as a forever chemical. Research into the health effects of swallowed coating flakes and manufacturing by-products is ongoing.