Starting at 8:54 - the 1st 40 stories of the North Tower/WTC 1 were built with asbestos but it was taken out and replaced with other insulation; asbestos was realized to be bad and outlawed around 1969/1970. Everything above the 40th story there was built without asbestos. The South Tower/WTC 2 never had asbestos from the ground up.
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"They're on our left, they're on our right, they're in front of us, they're behind us...they can't get away this time." -- Col. Puller, USMC