Reading this thread gives me the impression that we are in no way prepared for terrorist attacks. To suggest plastic sheeting and duct tape with no further instructions is just about useless. I can only hope that lack of preparation indicates a belief that we, as a civilian population, are in no real danger and that the color code system is in place to give us a sense of participation. I would hate to think that the safety of us civilians is an after thought.
I too wondered if you do a good enough job with the plastic wrap and duct tape to keep out gas, how long before suffocating. What about a biological attack?