I wonder at what temperature teflon becomes hazardous?

I make my living fixing laminators that use a teflon coated heat shoe,
they run below 350 degrees most commonly under 300. if they are found
to be dangerous its time for a new job.

I used to fix machines that used methyl alcohol, that job ended when
the healt risks of methyl vapors was publicized. oddly enough its still
used today in windshield washer fluid.

but those oither machines all went to the landfill........