In the quarry I worked at, it was the 1st year apprentices job to vacuum the electrical workshop on Friday afternoons.
As you can imagine, a lot of stone dust collects around the place. The vacuum had a metal nozzle. If they forgot to fit the anti static band to it that we had made, you got a hell of a crack from it. It was audible from across the workshop. Needless to say, they only forgot to fit it a couple of times.
The static can easily reach >100k volts.