Small dry powder fire extinguisher with a hose?

[JumbleDuck]

I'm thinking of a comparison with CO (moomba) which binds with haemoglobin in preference to O2 and can have lasting effects. The CO2 from an extinguisher may asphyxiate or cause panic but so far as I know it isn't actually poisonous.

At low concentrations CO₂ is an asphyxiant but at higher ones it is toxic. See https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5380556/, for example.