According to a theory advanced by a SINTEF materials scientist, a mixture of water from sprinkler systems and molten aluminium from melted aircraft hulls created explosions that led to the collapse of the Twin Towers in Manhattan.
Just before the two New York skyscrapers collapsed on Sept. 11, 2001, powerful explosions within the building could be heard, leading many people to believe that overheated steel beams in the building were not the cause of the collapse.
The explosions fed the conspiracy theories that someone had placed explosives inside the towers.
Interesting and quite long interview with the author is included. This work was presented at a materials conference and is published in the journal Aluminum International Today.