The Sept. 11 attacks and the U.S. military response in Afghanistan are both easily seen. What is generally unseen is the joint responsibility of New York City politicians, Port Authority bureaucrats, and eco-demagogues for many of the deaths.
For a steel-frame skyscraper to survive a large fire, the structural steel columns must be insulated because steel loses most of its strength when red hot. The Empire State Building (and all other steel-frame skyscrapers of its era) enclosed the steel support columns with a couple of feet of concrete to provide this thermal protection. This added a great deal of weight and cost to the buildings while also consuming a substantial amount of interior space.
In 1948, Herbert Levine invented an inexpensive, compact, lightweight, spray-on structural steel thermal insulation comprised of asbestos and rock wool. This did much to improve the economics of skyscrapers and played a major role in the post-World War II office tower construction boom.
In 1971, in the middle of constructing the two WTC towers, New York City banned the use of asbestos. This created a real problem for the WTC’s builders. The structural steel in the first 64 floors was already insulated with asbestos. Use of the traditional heavy, thick concrete insulation for the remaining 54 floors was impossible with the existing lightweight construction. The Port Authority wasn’t about to tear down the half-completed towers and start over again. So the builder’s jury-rigged a nonasbestos substitute. Back in the 1970s, Herbert Levine said, “If a fire breaks out above the 64th floor, that building will fall down. ” He was right.