Nov 282011
 

http://aotearoaawiderperspective.wordpress.com/2011/11/29/towers-of-dust/

In a conventional demolition the intent is maximum destruction with minimum pollution of the environment. This means that all asbestos, gypsum, heavy metals and other pollutants are removed before the demolition. The average pile remaining is about 12 % of the original height. Here is what happened to the twin towers on 911: