The film clips of the explosion do not seem that destructive. This was not an Oklahoma City bombing. The damage incurred by the buildings seems pretty light, more like collateral damage instead of what you would expect from a targetted bombing. Something that could have been caused by a propane tank or a meth-lab gone wrong. But then the evacuation warning doesn't fit.

With the broadcast of an evacuation warning, and the lack of real structural damage done, this seems more like an intentional distraction. The connection to ATT is tenuous at best.