Explosives Found in
World Trade Center Dust
Scientists Discover Both Residues
And Unignited Fragments
Of Nano-Engineered Thermitic Pyrotechnics
In Debris From the Twin Towers
byJim Hoffman
Version 1.00, April 3, 2009
Version 1.01, April 9, 2009
Version 1.02, October 23, 2009
Version 1.03, December 7, 2009
Introduction
The scientific paper Active Thermitic Material Discovered in Dust from the 9/11 World Trade Center Catastrophe conclusively shows the presence of unignited aluminothermic explosives in dust samples from the Twin Towers, whose chemical signature matches previously documented aluminothermic residues found in the same dust samples. The present review of the paper and related research is intended to summarize those findings for the non-technical reader. To that end, I first provide a short introduction to the subject of aluminothermic explosives, then outline the methods and results of analysis of the dust samples, and finally explore the significance of these findings.
Contents
- Introduction
- Contents
- Aluminothermics 101
- Aluminothermics at the WTC
- Discussion
- FAQ: Controlled Demolition With Aluminothermics
- How Could Thermite, an Incendiary, Demolish the Towers, When Buildings Are Normally Demolished Using High-Explosive Cutter Charges?
- Why Weren't Demolition Charges Triggered by the Plane Crashes or the Subsequent Fires?
- How Could the Demolition Equipment Have Been Installed in the Twin Towers Without Tenants Noticing?
- FAQ: Controlled Demolition With Aluminothermics
- Glossary of Analytical Methods
- References
Aluminothermics 101
Image from AmazingRust.com of a simple thermite reaction involving iron oxide and aluminum. This video shows thermite melting through a car. |
Backers of the official account of 9/11, including NIST officials, have dismissed evidence that aluminothermics were used to destroy the World Trade Center skyscrapers, claiming that thermite's slow reaction rate makes it an unsuitable tool for demolishing buildings. Despite repeated requests by scientists and researchers to address the potential role of advanced aluminothermic composites with high explosive power, officials have refused to acknowledge such materials.
Composition
2 Al + Fe2O3 → Al2O3 + 2 Fe |
The canonical thermite reaction is simple, lacks the aromatic hydrocarbons and nitrogen found in conventional high explosives, and is highly exothermic. |
Reaction Rate
Energy Density and Power Density
material | energy density | |
---|---|---|
by mass: MJ/KG | by volume: MJ/L | |
aluminothermic incendiaries | ||
Thermite (Al + Fe2O3) | 4.13 | 18.40 |
Copper Thermite (Al + CuO) | 4.00 | 20.90 |
nitro-aromatic explosives | ||
TNT (Trinitrotoluene) | 4.61 | 6.92 |
In terms of energy density, thermite is roughly comparable to TNT, packing slightly less energy per unit of mass but about three times as much energy per unit of volume. In terms of power density, thermitic preparations range across a wide spectrum, whose upper end appears to be comparable to conventional high explosives. 1 2
Because thermites have historically had much lower power densities than conventional high explosives, they are classified as incendiaries rather than explosives -- a classification that has been exploited to conceal the use of aluminothermics in the World Trade Center attack. Despite the fact that high-tech aluminothermics have existed and been used by the military since the mid-1990s or earlier, methods of identifying explosive residues at crime scenes are frequently limited to analysis of nitro-aromatic explosives. 3
Energetic Nanocomposites
The term 'nano-thermite' applied to the unignited thermitic material discovered in World Trade Center dust, is potentially misleading because it doesn't capture the complexity and sophistication of this material or its known analogs. Perhaps a better term is energetic nanocomposites, a class of materials that has been used by the military for some time in applications spanning propellants, armor-piercing munitions, and reactive armor. In their diverse roles, energetic nanocomposites fulfill a range of requirements including: "high density, good mechanical properties, low sensitiveness, good stability, low cost, ease of manufacturing, and environmental acceptability." 4 To achieve these requirements, scientists developing advanced aluminothermic materials have learned to embed the fine powders in a carbon- and silicon-rich matrix. Kevin Ryan explains:
The mixing [of ultra fine grain (UFG) aluminum and UFG metal oxides] is accomplished by adding these reactants to a liquid solution where they form what are called "sols", and then adding a gelling agent that captures these tiny reactive combinations in their intimately mixed state (LLNL 2000). The resulting "sol-gel" is then dried to form a porous reactive material that can be ignited in a number of ways. 5
Graphic from a DTIC (Defense Technical Information Center) Review publication on advanced energetic materials. |
Energetic materials such as aluminothermic sol-gels have been an active area of research in the US national labs since the mid-1990s or earlier, including under the auspices of NIST itself -- a fact documented by Kevin Ryan in his extensively footnoted article The Top Ten Connections Between NIST and Nano-Thermites. Also called "metastable intermolecular composites", "nano-structured energetic materials", or just "nanoenergetics", these materials have been the subject of numerous conferences, research papers, and patents in the past two decades. 6 7 8 9 10 11 It's also not difficult to find recent published papers on methods of reliably igniting such materials with minute low-power devices described as MEMS (microelectromechanical systems) and manufactured much like conventional integrated circuits. 12 13 14 15 16 17 18 It requires little imagination to grasp how such techniques could be exploited to implement a covert, all-wireless controlled demolition.
Aluminothermics at the WTC
The discovery of unexploded super-thermite in the WTC dust augments a large body of evidence pointing to the use of aluminothermic materials in the destruction of the skyscrapers. The present review looks only at the evidence of explosives found in the dust and debris expelled from the Twin Towers.
Even before WTC dust was subjected to the kind of microscopic scrutiny described in Active Thermitic Material Discovered, several features of the dust analysis published by the USGS pointed to the use of aluminothermics. For example, the USGS data shows high levels of barium -- a fact that is difficult to explain, barring pyrotechnics. The high levels of iron and aluminum in the dust -- each ranging from 1.3 to 4.1 percent of the dust samples by weight -- also appears anomalous, although prosaic sources of the metals can be imagined.
Aluminothermic Residues: Iron-Rich Spheroids
Micro-spheroidal particles in WTC dust consisting mostly of iron were documented in at least two scientific reports by 2005: a compilation of data by the USGS and a report for the owners of a skyscraper adjacent to the World Trade Center complex that sustained heavy damage in the attack. 19
Two images of iron-rich spheroids from the USGS Particle Atlas of World Trade Center Dust. 20 |
Illustration from a damage assessment report prepared for Deutsche Bank, the owners of a skyscraper severely damaged by projectiles from the South Tower. The report was commissioned, in part, to determine the nature and extent of contamination of the building, which is slated for demolition. |
Although it may be overlooked, the significance of these nearly microscopic iron-rich droplets is not difficult to grasp. Molten iron is one of the two principal products of the thermite reaction, the other being aluminum oxide, which tends to dissipate as an aerosol. The molten iron condenses and solidifies into particles whose size is a function of the thermite's reaction rate. Fast-acting super-thermites produce tiny droplets that become very nearly spherical due to surface tension.
The inescapable fact is that these spheroidal droplets in the WTC dust look exactly like the products of the combustion of nano-thermite explosives, and their discovery in consistently substantial concentrations in diverse samples of dust from the day of the attack weighs heavily against theories that they were generated by something other than the Twin Towers' destruction. Elemental analysis of these droplets described below would show that they are dead ringers for known aluminothermic residues.
In a 2007 paper, Steven Jones described the importance of the iron-rich microspheres. 21
Dr. Steven E. Jones describing molten metal seen at Ground Zero. |
As usual, we search for possible prosaic explanations for these metallic spherules in the WTC dust. The most obvious possible source is the melting of large quantities of steel in the buildings followed somehow by formation of tiny droplets of molten steel. As discussed above, however, steel melts at about 1538ºC (2800ºF) – and the temperatures in the buildings were no where near [sic] hot enough to melt steel, and certainly not in large quantities required for the amounts seen in the dust (and pouring out of the South Tower before collapse). Furthermore, we have looked at the chemical compositions of a number of iron-rich spherules as well as that of steel, and the compositions are not the same at all. It should not be surprising, however, as we analyze more spherules to find some that are steel-like in composition, assuming that thermite cutter-charges were in fact used to cut through steel. We should then find both steel- and thermite-residue spherules.
Could these droplets be due to molten aluminum alloy (from the jets) striking rusty steel and/or other office materials to somehow generate the iron-rich spheres? We performed experiments with molten aluminum poured onto rusty steel, then onto crushed gypsum and concrete (on the rusty steel) – and observed no formation of iron-rich droplets at all nor any sign of vigorous chemical reactions.
After addressing arguments that the iron-rich droplets could have been produced by the rubble pile or clean-up operation -- the dust samples were collected too early and were too distant from the site to have been thus contaminated -- Jones makes a rough estimate of the total quantities of reactants involved in the attack based on the fraction of the dust comprising the iron-rich spheres.
One can estimate the implied amount of thermite needed to generate so many iron-rich spheres in the WTC dust. In a sample of 32.1 grams of WTC dust, I observed with the unaided eye two metallic-looking spheres, in addition to the micron-sized spherules collected using a magnet. The mm-size spheres proved to be iron-aluminum rich. The mass of these two larger spheres (0.012g) found in this sample can be used to provide a crude estimate of the fraction of iron-rich spheres in the dust: 0.012g/32.1g = 0.04%. If the mass of the WTC dust was about 30,000 tons, then the iron-rich spherule content would be of the order of ten tons. This is a very rough estimate based on one small sample, and is only provided to give an idea of the amount of thermite-type reactants and products which may be involved here. An investigation well beyond the scope of this paper would look for purchases of aluminum and iron-oxide powders (and sulfur) in multi-ton-quantities prior to 9/11/2001.
A paper published a year earlier than Active Thermitic Material Discovered showed that metal-rich spheroids in WTC dust had iron-to-oxygen ratios indicating abundant elemental iron, such as found in thermite residues. It also pointed out several other features of WTC remains that indicated exposure to temperatures far above what could be produced by fires burning jet fuel and office contents, including: iron-rich and silicate spherules, volatilized lead, a molybdenum spherule, and materials with a "Swiss-cheese appearance". 22 Molybdenum has a very high melting point of 2617ºC.
Unignited Aluminothermics: Bi-Layered Chips
Provenance of the Samples
Physical Structure of the Chips
Portions of Fig. 4 and Fig. 5: Two scanning electron microscope images of bi-layered chips. |
Fig. 9, showing a highly magnified view of the red layer. Note the hexagonal plate-like particles, and the smaller faceted particles, both lighter in color than the porous matrix. |
Chemical Composition of the Chips
XEDS spectra of red and gray layers shows a remarkable similarity across the different samples.
Fig. 7: "XEDS spectra obtained from the gray layers from each of the four WTC dust samples ..." | Fig. 6: "XEDS spectra obtained from the red layers from each of the four WTC dust samples ..." |
Fig. 10, showing the BSE image and accompanying XEDS maps for Fe, Al, O, Si, and C of a portion of an untreated red layer. |
Fig. 15, showing the BSE image and accompanying XEDS maps of Fe, Al, O, Si, and C for a red-layer sample soaked in MEK. |
- gray layer: a hard homogeneous ceramic
composition: iron and oxygen - red layer: an engineered nano-composite substance, comprising:
- matrix: a nano-structured semi-transparent porous material
composition: silicon, oxygen, and carbon - particles: homogeneously embedded in the matrix and consisting of:
- thin predominantly hexagonal plates
dimensions: ~40nm thickness, ~1000nm diameter
composition: mostly aluminum, with small amounts of carbon and oxygen - rhombic faceted grains
dimensions: ~100nm diameter
composition: mostly iron and oxygen, probably as Fe2O3, with small amounts of silicon, sulfur, and carbon
- thin predominantly hexagonal plates
- matrix: a nano-structured semi-transparent porous material
Thermal Behavior of the Chips
Fig. 19 compares the DSC traces of a chip from each of the four samples. |
Ignition Residue Analysis
Conclusions
- It is composed of intimately mixed aluminum, iron, oxygen, silicon and carbon. Lesser amounts of other potentially reactive elements are sometimes present, such as potassium, sulfur, barium, lead and copper. [4,6]
- The primary elements (Al, Fe, O, Si, C) are typically all present in particles at the scale of tens to hundreds of nanometers, and detailed XEDS mapping shows intimate mixing.
- On treatment with methyl-ethyl ketone solvent, some segregation of components was observed. Elemental aluminum became sufficiently concentrated to be clearly identified in the pre-ignition material.
- Iron oxide appears in faceted grains roughly 100 nm across whereas the aluminum appears in plate-like structures. The small size of the iron oxide particles qualifies the material to be characterized as nano-thermite or super-thermite. Analysis shows that iron and oxygen are present in a ratio consistent with Fe2O3. The red material in all four WTC dust samples was similar in this way. Iron oxide was found in the pre-ignition material whereas elemental iron was not.
- From the presence of elemental aluminum and iron oxide in the red material, we conclude that it contains the ingredients of thermite.
- As measured using DSC, the material ignites and reacts vigorously at a temperature of approximately 430ºC, with a rather narrow exotherm, matching fairly closely an independent observation on a known super-thermite sample. The low temperature of ignition and the presence of iron-oxide grains less than 120 nm show that the material is not conventional thermite (which ignites at temperatures above 900ºC) but very likely a form of super-thermite.
- After igniting several red/gray chips in a differential scanning calorimeter run to 700ºC, we found numerous iron-rich spheres and spheroids in the residue, indicating that a very high-temperature reaction had occurred, since the iron-rich product clearly must have been molten to form these shapes. In several spheres, elemental iron was verified since the iron content significantly exceeded the oxygen content. We conclude that a high-temperature reduction-oxidation reaction has occurred in the heated chips, namely, the thermite reaction.
- The spheroids produced by the DSC tests and by the flame test have an XEDS signature (Al, Fe, O, Si, C) which is depleted in carbon and aluminum relative to the original red material. This chemical signature strikingly matches the chemical signature of the spheroids produced by igniting commercial thermite, and of many of the micro-spheres found in the WTC dust. [5]
- The presence of an organic substance in the red material is expected for super-thermite formulations in order to produce high gas pressures upon ignition and thus make them explosive. The nature of this organic material in these chips merits further exploration. We note that it is likely also an energetic material, in that the total energy release sometimes observed in DSC tests exceeds the theoretical maximum energy of the classic thermite reaction.
Discussion
That discovery also undermines the oft-heard claim that no explosives residues were found, a claim that was never compelling, given the apparent lack of evidence that any official agency looked for evidence of explosive residues of any kind. Worse, the public record shows that NIST not only failed to look for such evidence, it repeatedly evaded requests by scientists and researchers to examine numerous facts indicating explosives and incendiaries .
I expect that collapse theory defenders will dismiss the discovery of active thermitic material in the same way that they dismissed the thermite residues: by claiming that the samples were contaminated and/or that there are other explanations for the origin of these artifacts than pyrotechnics in the WTC Towers. "Debunkers" have proposed that the iron-rich spheres were fly ash residues embedded in the Towers' concrete, ignoring that the iron constituents in fly ash are oxides rather than elemental iron. How will they explain away the bi-layered chips, whose red layers have iron oxide and elemental aluminum in the ratio of Fe2O3 thermite as nano-sized particles of uniform shape?
As the work of explaining away the direct evidence of explosives becomes more daunting, we will probably see even more reliance on the mainstay of arguments against controlled demolition: those alleging that insurmountable obstacles would face such a project. Three of the most salient such workability arguments are:
- That the surreptitious preparation of the Twin Towers was too prone to exposure.
- That setting up the demolitions to start from the Towers' crash zones was technically unfeasible.
- That thermite is unsuitable as a tool of controlled demolition.
These arguments have taken on the appearance of straw men with their continued repetition -- including by NIST itself -- after being publicly shown to be based on false assumptions. The 9-11Research FAQ on Demolition addressed the first two starting in 2004, and Steven Jones and others addressed the third starting in 2006 by pointing out the existence of explosive variants of thermite.
FAQ: Controlled Demolition With Aluminothermics
How Could Thermite, an Incendiary, Demolish the Towers, When Buildings Are Normally Demolished Using High-Explosive Cutter Charges?
As is obvious from a review of the literature on energetic materials, thermite-based pyrotechnics can be engineered to have explosive power similar to conventional high-explosives while providing greater energy density and much greater stability. Thus, aluminothermic cutter charges similar to the shaped charges used in commercial demolitions are entirely feasible. However, a variety of forms of thermite might be used to demolish a steel-framed skyscraper in a way that uses no cutter charges at all, as in this Hypothetical Blasting Scenario, which posits three types of aluminothermic pyrotechnics: a thermate incendiary coating sprayed onto steelwork, nano-thermite kicker charges placed near steelwork, and thin-film nano-composite high-explosives distributed throughout the building. The strategically applied incendiary coatings, ignited several minutes before the building's take-down, weaken the structure; but obvious failures start only when the kicker charges break key supports, and the thin-film high-explosives begin pulverizing the building from the initial failure zone outward.
Why Weren't Demolition Charges Triggered by the Plane Crashes or the Subsequent Fires?
Perhaps the plane crashes did trigger some of the charges. If so, their blasts were lost in the jet-crash fireballs, and their damage was insufficient to budge the Towers' tops. Thermite incendiaries in the core ignited by the crash would not be visible over the fires, unless dislodged to the building's exterior, as apparently happened in the South Tower. However, this probably wasn't an issue because, in contrast to conventional explosives, thermite has a very high ignition temperature -- above 900ºC. Thus, thermitic incendiaries used around the crash zones could have been designed to survive the fires. As for thermitic explosives, they could have been designed to detonate only on exposure to the very extreme conditions of temperature and pressure provided by specialized detonators, and to deflagrate (merely burn) in response to the kinds of pressures and temperatures produced by the plane crashes and fires. As a fail-safe, the demolition sequence could have been programmed to be triggered by premature ignitions of pyrotechnics.
How Could the Demolition Equipment Have Been Installed in the Twin Towers Without Tenants Noticing?
Glossary of Analytical Methods
An electron microscope equipped with an EDAX GENESIS 2000 X-Ray Microanalysis System. |
EDS spectrum of a yellow paint sample, from ModernMicroscopy.com. EDS spectra allow the easy identification of the most abundant elements in a sample, while requiring some analysis to estimate relative quantities. |
DSC: Differential Scanning Calorimetry
A technique that determines the difference in the amount of heat required to increase the temperature of an experimental sample and reference. A differential scanning calorimeter outputs a DSC trace which shows the relationship of heat flux to temperature, and thereby exothermic or endothermic behavior of the sample. 23
SEM: Scanning Electron Microscopy
A type of electron microscopy in which a beam of high-energy electrons scans the surface to a sample to image its structure or composition.
XEDS: X-ray Energy-Dispersive Spectroscopy
A technique for determining the elemental composition of a sample using an instrument that analyzes the spectrum of emitted X-rays from a sample as a beam of high energy electrons is directed onto its surface. 24
A single workstation may provide integrated BSE and XEDS capabilities using SEM equipment fitted with specialized BSE and XEDS detectors, where software controls the electron beam, sample positioning, and detector parameters.
References
- 1. Nanoscale Chemistry Yields Better Explosives, llnl.gov, [cached]
- 2. Daniel Tappmeyer studies how nanoparticles can be used for quick ― but controlled ― energy release, undergradresearch.missouri.edu, [cached]
- 3. Analysis of Trace Residues of Explosive Materials by Time-of-Flight LC/MS, www.chem.agilent.com, 3/16/2005 [cached]
- 4. Advanced Energetic Materials: New Energetic Materials, National Academic Press, [cached]
- 5. The Top Ten Connections Between NIST and Nano-Thermites, 7/2/2008
- 6. Reactive Projectiles Comprised of Metastable Intermolecular Composites, lanl.gov, [cached]
- 7. Energy dense explosives, USPTO.gov, [cached]
- 8. Inorganic metal oxide/organic polymer nanocomposites and method thereof, USPTO.gov, [cached]
- 9. Nano-scale energetic materials fabrication, characterization and molecular modeling, European Materials Research Society, [cached]
- 10. Formation of Nanostructured Energetic Materials via Modified Sol-Gel Synthesis, mrs.org, [cached]
- 11. Metastable intermolecular composite, en.wikipedia.org, [cached]
- 12. On-Chip Initiation and Burn Rate Measurements of Thermite Energetic Reactions, mrs.org, [cached]
- 13. Unique Porous Copper Structure Enables New Generation Of Military ..., sciencedaily.com,
- 14. Integrated thin film explosive micro-detonator, www.dodtechmatch.com/,
- 15. Military eyes MEMS weapons detonators that could be fabbed on IC lines, pennwellblogs.com,
- 16. MEMS microdetonator/initiator apparatus for a MEMS fuze, USPTO.gov,
- 17. In-plane MEMS thermal actuator and associated fabrication methods, USPTO.gov,
- 18. Method and system for making integrated solid-state fire-sets and detonators, USPTO.gov,
- 19. Damage Assessment 130 Liberty Street Property, RJ LeeGroup, Inc., 12/2003 [cached]
- 20. Particle Atlas of World Trade Center Dust, pubs.usgs.gov, [cached]
- 21. Revisiting 9/11/2001 -- Applying the Scientific Method, JournalOf911Studies.com,
- 22. Extremely high temperatures during the World Trade Center destruction, JournalOf911Studies.com,
- 23. Differential Scanning Calorimeters, tainstruments.com, [cached]
- 24. Energy Dispersive X-ray Spectroscopy (EDAX), AmazingRust.com,