Zyklon beets

Prussic acid is also a by-product of beet sugar production, and a method of obtaining the chemical from beet-molasses wastewater (the liquid left over after you get the sugar out) was patented in 1915.

Although prussic acid has its benign uses, its most infamous application was as the main ingredient in Zyklon B, the Nazi death camp gas.

It is concluded that the SS used the remaining 1 percent to murder about a million people.