Monsanto Phosphate Plant and Slag Pour, Idaho

Monsanto operates a phosphate plant at this location that dumps glowing molten phosphate ore down the edge of its slag pile around 5 times an hour, 24 hours a day. The 530 acre plant has operated since 1952, and the slag mound is an elevated landscape, growing slowly at its edges, and is 150 feet high in places. The mined phosphate ore is subsequently refined into elemental phosphorus, which is then used in many products, including toothpaste, foods, cleansers, fertilizers, and herbicides (including Monsanto's own Roundup). Monsanto is not alone, as there are other large producers of chemicals and fertilizers to be found in the valley, such as Agrium US Inc., and J. R. Simplot Co.