Thermite

Theories that Aluminothermic Reactions Were Used to Destroy the Twin Towers

The idea that thermite or similar preparations were used exclusively or in combination with other methods to destroy the Twin Towers remained unexamined for several years after the attack, despite its merits.

Aluminothermic reactions are exothermic chemical reactions in which aluminum is oxidized while an oxide of another metal is reduced. Although high temperatures are required to initiate such reactions, they are easily self-sustaining once started due to the heat they generate. The most common example of an aluminothermic reaction is thermite, in which powdered aluminum reacts with an iron oxide. Because aluminum has a greater affinity for oxygen than iron, oxygen is transferred from the iron oxide to the aluminum, releasing a great deal of energy and leaving behind molten iron and aluminum oxide.

These frames show the northeast corner of the South Tower seconds before its precipitous fall. The spout of orange molten metal and rising white smoke has the appearance of a thermite reaction.

Professor Steven Jones has noted that a number of features evident both before and after the falls of the Towers fit the theory that thermite was used. These include:

• A spout of orange molten metal seen just before the South Tower's fall in videos of the Tower's north face around the crash zone
• Reports of molten metal in the remarkably hot rubble of Ground Zero
• Minute solidified droplets of previously molten iron in samples of World Trade Center dust
• Remains of the Towers' structural steel showing severe corrosive attack involving sulfur
• High levels of metals found in aluminothermic incendiaries -- such as manganese, zinc, and barium -- in samples of World Trade Center dust

Basic thermite preparations can be modified and augmented in various ways to change their properties. The fineness of the aluminum powder determines the speed of the reaction. The use of ultra-fine aluminum powder gives the reaction an explosive quality, resulting in 'super-thermites'. The addition of sulfur in preparations called thermates enhances the ability of the reaction to cut through steel.

Findings reported in Appendix C of FEMA's World Trade Center Building Performance Study seem to fit the thermite theory remarkably well.