For months after the destruction at the World Trade Center (WTC) on 11th September, 2001, the ﬁres at Ground Zero (GZ) could not be put out, despite the following facts.

Abstract Investigators monitoring air quality at the World Trade Center, after the September 11th attacks, found extremely high levels of volatile organic chemicals as well as unusual species that had never been seen before in structure ﬁres. Data collected by the U.S. Environmental Protection Agency indicate striking spikes in levels of benzene, styrene, and several other products of combus- tion. These spikes occurred on speciﬁc dates in October and November 2001, and February 2002. Additionally, data collected by researchers at the University of California Davis showed similar spikes in the levels of sulfur and silicon compounds, and certain metals, in aerosols. To better explain these data, as well as the unusual detection of 1,3-diphenylpropane, the presence of energetic nanocom- posites in the pile at Ground Zero is hypothesized.

•Several inches of dust covered the entire area after the destruction of the WTC buildings.

•Millions of gallons of water were sprayed onto the debris pile.

•Several rainfall events occurred at GZ, some heavy; and

•A chemical ﬁre suppressant called Pyrocool was pumped into the piles (Lipton and Revkin 2001).

The characteristics of these un-extinguishable ﬁres have not been adequately explained as the results of a normal structure ﬁre, even one accelerated by jet fuel. Conversely, such ﬁres are better explained given the presence of chemical energetic materials, which provide their own fuel and oxidant and are not deterred by water, dust, or chem- ical suppressants.

Apart from the extensive but failed efforts to extinguish the ﬁres, there are several other physical indicators of the presence of energetic chemical reactions in the rubble at GZ. These include the following.

1.Photographs and witness testimony evidencing molten metal and explosions accompanied by white dust clouds (Jones 2006; Meyerowitz 2006; PBS 2002).

2.Extremely high temperatures in the ﬁres at the WTC (Jones et al. 2008a).

3.Unusual spikes in volatile organic chemical (VOC) emissions, suggesting abrupt, violent ﬁres on speciﬁc dates.

4.Unusual species in the environmental monitoring data, also corresponding to speciﬁc dates.

Explosions followed by white dust clouds, and molten metal at GZ, are of particular interest in this analysis. A white dust cloud is one of the products of the thermite reaction. The white dust in this case is aluminum oxide,