(9:59 a.m.-11:00 a.m.) September 11, 2001: US Geological Survey Scientists Watch WTC Collapses on TV, Realize Dust Is Harmful

Scientists who work for the US Geological Survey watch the World Trade Center towers collapse on their television sets. “We sat at home, watched that gray-white cloud roll over Lower Manhattan, and knew damned well that the dust was going to hurt a lot of people,” Gregg Swayze, a USGS geophysicist, will later tell the St. Louis Post-Dispatch. “I knew we had the best technology in the world to determine precisely what was in that dust.” [St. Louis Post-Dispatch, 2/10/2002] Swayze and other USGS scientists quickly get to work making arrangements to use USGS and NASA equipment to determine the composition of the dust clouds (see September 12, 2001).