Hello,  PTFE ("Teflon", polytetrafluoroethylene) in its various forms
is one of my favorite materials classes with all sorts of uses.  For
example, I just improved the working of my 80 year old water heater,
dramatically, with a small piece of tutkite[?], a dense hard PTFE
compound.  Just about anything I build or rebuild has some PTFE in
it somewhere.

However, PTFE is also very hazardous if inhaled.  Aerosol and powdered
forms are easy to inhale but the body has a very difficult time
eliminating them because PTFE is extremely inert and also hard to get
a grip on.  The body tends to encapsulate it instead of eliminating it,
the same way it deals with asbestos.  So most of the PTFE you inhale
will be there for your life, interfering with your respiration.

The worst way to inhale PTFE is by burning it, which requires fairly
high temperature, but it does burn and the byproducts, including fine
particulates, are extremely dangerous.  It has been suggested that even
short-term exposure to burning PTFE will give you lung disease if you
live long enough.

I don't know how severe the risk is with aerosol or powdered forms,
but I suggest taking serious protective measures when using these
forms.  Machining is probably safe in most cases other than sanding.
Do not sand Teflon!

Best regards,
Spencer Chase