Absolutely, but grain dust explosions were more common in the Grain Elevators (municipal sites, when large amounts of grain were transported), and people were smoking in the area. I grew up in an agricultural area, well aware of the dangers.

But, they are just not that common, as most sites drop grain in unlit, buildings through a roof vent. The grain is then drained, as needed through a gravity feed system. Grinding machines generally have magnetic bars to capture any metal (nails, nuts, etc) to prevent sparks. Don't know how many thousands of tons of grain we ground for farm food over the decades. Dozens of tons a week. Pretty much every farm has a grinding system.

Does it happen? Yup - but getting hit by lightning is probably more common. i could see a propane heater leaking and going off - but again, this just isn't a common thing.