St. Anthony Falls and the Mill That Exploded
Near Minneapolis St Paul, Minnesota
St. Anthony Falls is the only natural waterfall on the entire length of the Mississippi River. From its headwaters at Lake Itasca in northern Minnesota to the Gulf of Mexico, two thousand three hundred miles south, this is the only place the river drops over a rock ledge in a single unbroken fall. It is not a dramatic waterfall by any standard measure. The drop is about fifty feet, by historical accounts. But it was enough to power the largest flour-milling complex in the world.
Between eighteen eighty and nineteen thirty, the Washburn A Mill and the Pillsbury A Mill, standing on opposite banks of the falls here in Minneapolis, processed grain shipped in from across the northern Great Plains. At peak production, the mills here produced enough flour to bake twelve million loaves of bread per day. The brand names that came out of this stretch of river, Gold Medal and Pillsbury, are still on shelves in grocery stores across the country.
On May second, eighteen seventy-eight, the Washburn A Mill exploded. Flour dust, suspended in air at certain concentrations, is as explosive as gunpowder. An ignition source in the mill, never definitively identified, triggered a chain explosion that destroyed the mill entirely and ignited five adjacent mills. Eighteen workers died. The explosion shook the city and was heard miles away. A block of downtown Minneapolis burned.
Washburn rebuilt the mill stronger and added ventilation systems that are now standard practice in flour processing. The rebuilt mill operated until nineteen sixty-five. The ruins are now the Mill City Museum, built inside the rubble. The waterfall itself is controlled today by the Army Corps of Engineers, channeled through concrete aprons and underground tunnels to prevent the limestone bedrock from eroding further and undermining the city above it.
