I can answer this factually. The first Tower was 40% completed with asbestos before they switched. Also, the architects later assessed that the buildings did not have enough fireproofing, so a kind of fiberglass concrete Fireproof material was sprayed on the undersides of the floors and on all of the support trusses. That is why there was so much dust as the WTC collapsed. The floors were only four inches thick of concrete on trusses, with this fireproofing sprayed underneath. It was all of the fireproofing material that they had sprayed on after the buildings were completed but not yet finished for occupancy.
I can answer this factually. The first Tower was 40% completed with asbestos before they switched. Also, the architects later assessed that the buildings did not have enough fireproofing, so a kind of fiberglass concrete Fireproof material was sprayed on the undersides of the floors and on all of the support trusses. That is why there was so much dust as the WTC collapsed. The floors were only four inches thick of concrete on trusses, with this fireproofing sprayed underneath. It was all of the fireproofing material that they had sprayed on after the buildings were completed but not yet finished for occupancy.
ThanQ.