Dust in the air, whether starch, flour or wood dust, is highly explosive. We've had 2 lumber mills explode & burn as well as the old flour mill back home in Dorchester Ont.
exploded and burned. Dust is bad, however, the static experiment also used ground up BP, to "Dust" & the flood of sparks just made the dust particles "blast" to outside the pile.
Very interesting indeed , which brings up the question -
are there forms of static electricity, natural due to packaging, etc, which produce the amperage necessary to combust black powder?(other than lightening)