They say no pieces fell to the ground, but the vapor could contain microbes. Some think that there was a good chance that the explosion at Tanguska was a comet that brought the "Spanish Influenza" pandemic in 1918-1920 that killed 20-50 Million. The aftereffects of that were felt well into the 20s. Time will tell.The brilliant streak of light was spotted across a wide swath of the West from Reno to San Francisco before dawn on Jan. 17. The New York-based American Meteor Society received reports from about 50 people in California and Nevada who saw the bright light.Seti Institute scientist Peter Jenniskens tells the San Francisco Chronicle the flash of light was a small comet that flamed out when it hit the Earth's atmosphere.
Fireball across Skies in West was Flaming Comet