What is it?

Rozol: Its chemical name is chlorophacinone. It is an anticoagulant rodenticide.

Zinc phosphide: Used to treat oats, it is a heavy, finely ground, crystalline gray-black powder that is practically insoluble in water and alcohol. It was first synthesized in 1740 and was first used as a rodenticide in 1911-12 by the Italians. It was not used in the U.S. as a rodenticide until 1939 when it was used in place of strychnine, which was in short supply because of rodent control in Europe during W.W.II.

Magnesium or aluminum phosphide and gas cartridges: Fumigants that are placed in the burrow of prairie dogs.