Fan Roater Blows Up

I wanted to warn people about the Perfekt fan. Being very hot today I turned my fan to max. The next thing I heard a strange sound and the fan roater had come off. It came off so violently it exploded through the front cover. After cleaning up the pieces I returned to working on my computer. That is when I noticed keys were missing from my keyboard. Debris from the roater had blown them off. It could so easily have gone into my eye.