dispersion survey around the Pentagon. From April 19th to May 15th there will be sensors placed inside and around the Pentagon (including a stationary blimp and long range lasers from a distant location) that will chart the air flow going in and coming out of the Pentagon. There will also be several releases of sulfur hexafluoride (commonly known as SF6), a harmless chemical commonly used to track airflow in buildings. The sensors will detect the SF6 and record the time and intensity of the chemical. The actual tests (and releases of SF6) will probably take place in May. But all the data from the sensors (with, or without, the presence of SF6) will be used to build a computer simulation of air flow inside and around the Pentagon. This simulation will be used to plan modifications inside the Pentagon to make it more resistant to the effects of a chemical attack, and to aid in planning emergency evacuation plans if there were such an attack.
The U.S. Department of Defense is conducting an an atmospheric