An international terrorist organization is plotting to attack the U.S. Federal Building in Dallas, Texas. The terrorist organization has infiltrated the federal building maintenance and planning department, which has given those personnel access to evacuation plans and to storage areas as well as transportation inaccessible by the public. The plan is to plant numerous improvised disbursement devices containing mustard gas in the existing central air system throughout the building to not only kill and maim existing personnel and citizenry within the structure, but also to encourage a full evacuation of the building. Secondary and tertiary mustard gas devices have been located not only along the escape routes outside the building, but also in the typical first responder staging areas.
You are a member of the strategic/contingency planning committee for the city of Dallas. How can you design a plan that will prevent such attacks or at least provide the best response to these attacks?