In article ,
Jon Elson wrote:

I have seen a fat spark produced when firing off a CO2 fire extinguisher,
which seemed like a pretty big design defect.

You're certainly right - if you had used it around any sort of
flammable vapors, the spark might have started a fire. ;-)

They should have made the
hose and nozzle with a static dissipative material.

I'm not sure that would have helped. Where would the charge have
gone, during the second or three that one was blasting away with CO2?
There'd be only a very limited amount of charge flow back into the CO2
cloud (neither the CO2 nor the ice crystals which were
triboelectrically active, will be particularly conductive), or
dissipate into the air nearby. The major charge-sink would still be
the body of the person wielding the extinguisher.

http://www.ece.rochester.edu/~jones/demos/charging.html is
interesting. Apparently, even aluminum can generate a charge via
triboelectric effect, and it's about as static-conductive as you could
ask for.