Protecting Buildings against Airborne Contamination

Consider the following scenario. At 8:30 a.m. on an ordinary day at Central Headquarters facility, a vending machine service technician arrives. He shows his contractor badge to security, opens his toolbox for inspection, and walks though the metal detector. He is waved through and proceeds on his rounds. At his second vending machine cluster, he opens the machine, adjusts the coin mechanism , and casually places a shoebox-sized device behind the machine. He plugs the inconspicuous box into wall power and moves on to the next cluster. Within a half hour he leaves the building. As he drives away he activates the device by placing a cell phone call to its embedded receiver. A small pump begins to whir inside the box and emits a fine mist of antibiotic-resistant Bacillus anthra-cis spores into the hallway. Passersby notice no smell, see nothing in the air, and ignore the faint sound coming from the vending machine cluster. The mist quickly spreads through hallways into the ventilating system and permeates the building. Over the next hour, large numbers of Central Headquarters personnel are infected. Several days later, symptoms appear, many people are hospitalized, the building is closed, and a national security investigation begins. The enemy is nowhere to be found. This example is a dramatic but plausible illustration of the vulnerability of buildings and their occupants to airborne contaminants. Buildings are at well-known fixed locations and may be found in mixed-use urban areas with little or no restricted perimeter access. Prime candidates for chemical–biological (CB) attack include government headquarters, military facilities, courthouses, national banks, and other financial institutions. Other candidates for attack include assembly buildings (are