Modern (ie. Dupont) black powder granules are tumbled in fine graphite powder for 12 hrs. after granulation to coat them, this not only provides protection against electrostatic friction sparking but aids in prevention of absorbing water (or excessive drying). Not sure when they started doing this.
Brooklyn Navy Yard saw a number of catastrophic fires in the 20th C. from refuelling with oil, the rushing oil set up a static charge between the hose nozzle and the ship which would spark and ignite the fuel oil in the mostly empty oxygen filled tanks when it reached the appropriate air/fuel ratio and kaboom. they learned to ground strap the nozzle to the ship. Moving dry powders can have the same effect and gunpowder of course is not your friend when it happens. When I was stationed in New Orleans, I remember someone pointing out a bare area next to the Mississippi in the docks area, appears they once were the site of a trio of flour silos. Until one particularly dry day, a cloud of dry flour dust and air managed to spark itself and another Kaboom blew the rest of the flour into the equation and - no more silos. and a few less workers. In an odd twist, they found that a CO2 fire extinguisher being discharged can also cause an electrostatic spark that can set off an explosive air/fuel mixture. (they tried blanketing fuel tanks with a layer of CO2 - bad idea - more kabooms)
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