May 25, 2007: One of the things combat troops, especially engineers, in Iraq have to memorize are the various danger distances for roadside and car bombs. For example, a 500 pound bomb (of the size found in small cars, and just sitting on roadsides) is lethal out to about 30 meters. Or, as U.S. troops are reminded (in the most familiar terminology possible), about the third the length of a football field. This scales up in easily remembered values. A two ton bomb, usually found on a truck, is lethal out to about 60 meters. The largest type of truck bomb encountered, about five tons of explosives, is lethal out to a hundred yards. Beyond lethality, there is flying objects that extend out much further. The most troublesome flying objects are glass. For the 500 pound bomb, you have to worry about falling glass out to about 400 meters. For the two ton bomb, that's 800 meters, and for the five ton bomb, that's 1,200 meters. Beyond the falling glass zone, you are generally safe, and that's how far you have to evacuate your own troops, and civilians, when you are trying to disarm a bomb, or are going to destroy it in place. Naturally, if there are buildings, or any other type of sturdy obstacle, in the way, that will reduce the distances. While the larger bombs will flatten many types of structures, the lethal and danger zones are still smaller.