On May 2, 1878 there was an explosion of the flouring mills at Minneapolis, Minnesota at the Washburn A Mill. 18 workers were killed in the explosion, 14 of them killed instantly. The force of the explosion blew the mill’s concrete roof several hundred feet into the air. It leveled the 7 1/2 story limestone building. As a result of the explosion, the Humboldt and Diamond Mills were also flattened. Evidence investigated after the loss indicated that the Washburn A Mill exploded first, and the force of the explosion hit each of the other mills sequentially. The mill was originally built in 1874 and was declared the largest flour mill in the world. The Washburn A Mill was reconstructed in 1879. At peak production, the Washburn A Mill could grind over 100 boxcars of wheat, almost 2 million pounds of flour per day using 41 grinding stones. A monument to the 18 workers killed in the explosion was erected in 1885 in the Lakewood Cemetery. The inscription on the monument reads, “Labor wide as the earth has its summit in heaven.”