Polytetrafluoroethylene (PTFE)/Teflon

TL;DR

something.

A PFAS.

More commonly known as Teflon (manufactured by Chemours, a spin-off from DuPont).

Invented in 1938/

Probably safe. PFTE was manufactured using PFOA which is carcinogenic and is now made with it's replacement Genx which is actually turning out to be even worse. The PFOA is not present in the final product.

Gore-Tex and similar clothing materials are made using expanded PTFE.