Pipe bombs like the device that exploded in Atlanta's Centennial Olympic Park are among the most democratic instruments of destruction: They can be obtained by just about anyone.
Pipe bombs are easily constructed from household materials and capable of doing great damage.
"You don't have to be a chemist or a whiz at all to figure out what you need to make one," said Brent Smith, a criminology professor at the University of Alabama at Birmingham.
Because of that, said Smith, pipe bombs are popular with right-wing militias and domestic terrorist groups who lack training in explosives.
The simplest bomb consists of a metal water pipe stuffed with common explosive materials. The ends are capped, and a fuse _ often similar to the type used to detonate a firecracker _ is attached to one end.
When the fuse lights the explosive, it shatters the pipe, hurling shards of metal in every direction at a great velocity. A pipe bomb can be ignited by a wick or a computerized timer. It also can be designed to explode when dropped or rattled.
They are being used with frequency.
Statistics from the Federal Bureau of Alcohol, Tobacco and Firearms indicate that pipe bombs were involved in 81 percent of all U.S. bombings during the five-year period ending in December 1993. Those 3,081 incidents caused 46 deaths, 391 injuries and more than $9.1-million in property damage.
The Atlanta pipe bomb had nails and screws attached to it that were blown outward when the device exploded. That type of bomb can cause even more damage.
"They can be as small or as large as the imagination of the manufacturer," said Sgt. John Moir of the Suffolk County, N.Y., Police Emergency Services.
In April, federal authorities arrested members of a Georgia militia group who had manufactured more than a dozen pipe bombs. Reports initially said the bombs were intended for the Olympics, although it turned out one of the members had merely said they might be blamed if a pipe bomb went off at the Games.
Pipe bomb ingredients
Investigators believe the bomb that exploded in Centennial Olympic Park was a crude pipe bomb. Here are some of the common household items used in making pipe bombs:
Clock or watch
Pipe and end caps