I don't like where this is going. You'll read elsewhere that "oh, it's Teflon AF, so it's safe". And then citations of various temperatures which I believe are references to the so called polymer glass transition temperature, said variation of Teflon having a higher value.
I question whether that's the right metric.
For example,
"Typical molding temperatures for Teflon® AF 1600 range from 240 to 275°C (464 to 527°F); for Teflon® AF 2400, the range is 340 to 360°C (644 to 680°F). The polymer begins to
decompose above 360°C (680°F), so processing above that temperature should be avoided."
https://www.chemours.com/Teflon_Industrial/en_US/assets/downloads/h44015.pdf
Does that mean the company foreswears offgassing of toxics implicated in Teflon fever below that temperature? Absolutely not.
Let me put my legal hat on for a minute and look at this as a lawyer might. (It's clear the Dupont lawyers are calling the shots in fume offgassing disclosures).
The company does not say that any particular temperature is safe. All across their marketing and technical specifications, you'll see the following verbiage:
"WARNING!
VAPORS CAN BE LIBERATED THAT MAY BE HAZARDOUS IF INHALED.
Before using Teflon® AF, read the Material Safety Data Sheet and the detailed information in the 'Guide to the Safe Handling of Fluoropolymer Resins, 2nd Edition,' published by the Fluoropoly-mers Division of The Society of the Plastics Industry; copies may be obtained from your DuPont representative."
So they kick it to an industry publication,a recent version may be found here:
http://multimedia.3m.com/mws/media/778897O/fluoropolymer-safe-handling-en.pdf
Which says in part:
"Although fluoropolymers are amongst the most
thermally stable polymers known, they will start to
decompose slow ly when heated to elevated
temperatures.
There is some contradiction in the published litera-
ture as to the exact temperature at which decomposition occurs, reflecting the difficulty in analysing trace element emis sions. However, significant decomposition occurs only above the recommended continuous service temperature for the polymer in question. The quantity of effluent evolved remains small until temperatures above the normal processing temperature for the polymer are reached."