Abstract: Inert decomposition methods and systems are provided. A container is positioned in a containment environment filled with a first oxygen-free inert gas at a positive pressure in excess of ambient pressure surrounding the containment environment. The container has two ports and is partially filled with a material to be decomposed with the two ports disposed above the material to define a free volume. A second oxygen-free inert gas is circulated through the free volume via the two ports to remove moisture from the material wherein the second oxygen-free inert gas fills the free volume. The container with the second oxygen-free inert gas therein is heated to cause the material to undergo pyrolysis wherein the material decomposes into gases, liquids, and solids. During pyrolysis heating, the gases are removed via the two ports. The container is then cooled to reduce temperatures of the liquids and solids below flash-point temperatures thereof.