Teflon itself isn't poison. The entire point of teflon is that it's so chemically unreactive that nothing can even bind to it on a molecular level.

The problem with Teflon is that manufacturing it uses a lot of actually toxic chemicals incidental to making the Teflon bind to the metal of a pan and because it's so non-reactive and very brittle, general use and any disposal of it will result in Teflon molecules just floating around in the environment unable to be broken down by anything.