Chlorine Gas Attack by International Terrorists; case study

The Department of Homeland Security has done a very excellent job of spotting potential International Terrorist Plots after 9-11 and in doing so worked hard to prevent such targets from being exploited. Our think tank after 9-11 also has been thinking on this and we identified 20 worst case scenarios and then following the lead of DHS, figured out ways to shore up such risks. Below is worst case scenario number 11;