The state of Arizona is making preparations to execute death row inmates with the same chemical that was used in Auschwitz death chambers.

The state's department of corrections has spent more than $2,000 on the ingredients used to make cyanide gas.

According to documents obtained by The Guardian, a solid brick of potassium cyanide was purchased in December for $1,530, as well as sodium hydroxide pellets and sulphuric acid - all of which combined create the lethal gas.