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What are the most-cited technical rebuttals to claims about molten steel, thermite, or explosives at the WTC sites?
Executive summary
The most-cited technical rebuttals to claims about molten steel, thermite/nanothermite, or explosives at the World Trade Center focus on [1] eyewitness reports and photos being ambiguous or misinterpreted; [2] physical and chemical analyses of dust that critics say do not prove thermite or high explosives; and [3] engineering and materials‑science arguments that jet‑fuel fires and structural damage explain the collapses without demolition charges. Key rebuttals include NIST’s and other experts’ conclusions that observed “molten” material was likely aluminum or molten debris, that the red/gray “thermite” chips lack unambiguous thermite signatures, and that microspheres can form without explosives [4] [5] [6] [7].
1. “Molten steel” eyewitnesses vs. technical interpretation
Advocates cite many firefighter and worker testimonies describing molten metal and photos that appear to show glowing flows; skeptics and official reports counter that those observations are ambiguous and can be explained as molten aluminum or other debris, not bulk molten structural steel — NIST explicitly stated it did not report that steel melted due to the fires and said some bright glows were likely aluminum from the aircraft [4] [8]. Independent debunking sites also stress lack of clear photographic proof of pools of molten steel [9] [10].
2. Microspheres and “molten iron” — multiple origins argued
Proponents point to iron‑rich microspheres in WTC dust as evidence of very high‑temperature reactions consistent with thermitic material. Rebuttals note these spheres can form from small particles that have much lower melting behavior than bulk metal, and that ordinary mechanical and thermal processes in the collapse and cleanup can produce such spheroids; one critic group (New Mexicans for Science and Reason) argued very small metal particles melt differently, undermining the exclusive thermite interpretation [5] [11].
3. The Harrit/Jones “nanothermite” paper and scientific counterpoints
The 2009 paper claiming active thermitic material in dust (Harrit et al.) is frequently cited by proponents; rebuttals stress that explosives and thermite are not demonstrated conclusively by the tests used and that alternative, non‑energetic origins for the red/gray chips and microspheres exist. Journalistic and expert critiques emphasize that thermite is not a conventional explosive and that identification of primer paints, construction materials, or contamination are plausible alternative explanations [12] [13] [14].
4. NIST, FEMA and engineering responses on explosives and thermite
NIST’s investigations concluded that airplane impact and subsequent fires explain the collapses, found no evidence of a blast event, and stated that alleged thermitic signatures do not provide conclusive proof of pre‑placed incendiaries; NIST also argued that installing large amounts of thermite or explosives covertly in WTC 7 would have been difficult to conceal [4] [7] [15]. FEMA and NIST reports are repeatedly invoked by rebuttals to argue the forensic record does not require demolition hypotheses [4] [16].
5. Forensic chemistry disputes: interpretation of dust analyses
Proponents claim the presence of unusual elements (e.g., molybdenum in some dust studies) and organic binders as evidence of engineered energetic materials; rebuttals counter that such compounds can originate from building materials, plastics, paints or contamination and that chain‑of‑custody and sampling questions complicate claims that the dust proves thermite/explosives [16] [8] [7].
6. Practical demolition and acoustics: expectations vs. reported scene
Technical critics argue conventional controlled demolitions produce distinctive sounds, fumes, and preparatory activity; NIST and others note that detectable large‑scale emplacement of thermite/explosives would have been difficult without observations, while proponents reply that nano‑thermites and combined techniques might produce lower acoustic signatures — this remains a point of contention in the literature [5] [17] [15].
7. Where the debate is strongest — and weakest — in current reporting
Agreement exists that there were bright glows, high local temperatures, and iron‑rich particles in dust; disagreement centers on interpretation: whether those are unambiguous forensic signatures of thermite/explosives or explainable by aircraft aluminum, fires, and mechanical processes [4] [5] [12]. Available sources do not mention definitive third‑party replication that unambiguously proves explosive demolition in the WTC collapses; proponents point to peer‑reviewed claims (Harrit et al.) while critics cite methodological limits and alternative mechanisms [12] [14].
Caveats and limitations: reporting and technical papers cited here include both advocacy and critical sources; chain‑of‑custody, sampling methodology, and interpretation of microscopic and chemical data are repeatedly invoked as decisive weaknesses by both sides [12] [15].