さくさくと白黒
ある一定の濃度の可燃性の粉塵が大気などの気体中に浮遊した状態で、火花などにより引火して爆発を起こす現象

Quick and skillful black & white.
A phenomenon in which flammable dust present in a certain concentration is suspended in a gas and then ignited by a spark or similar, causing an explosion.