On Jun 25, 3:36 pm, Peetie Wheatstraw
wrote:
About 20 years ago I installed a tstat-controlled attic exhaust fan
suitable for a small-medium size attic.

Years later it caused tv/radio interference in the house, so I built
a frame for it and put it in a window in my detached 2-car garage
to improve air circ. in very hot weather.

The motor should not be creating EMI. If was creating radio
interference typically because it was failing. Maybe something as
simple as worn brushes. Maybe arcing on a loose wire. Or maybe a hall
effective sensor was not properly positioned.

No one can say if it is a fire hazard. But EMI was a precursor to
fan failure.

Only person who can answer the OP's question with authority is one
who opens that fan or who obtains a detailed autopsy report of that
fan. Most would simply replace the defecive motor.