When did countries start using lethal chemical concoctions and hazardous viruses, bacteria and toxins as weapons? Where do they come from? You're about to enter the world of biological and chemical warfare.
Chemical weapons were first used in World War I, and the nations of the world quickly and uniformly decided that these weapons went too far.
The first chemical weapon used effectively in battle was chlorine gas, which burns and destroys lung tissue.
In 1995, the group Aum Shinrikyo released sarin gas in the Tokyo subway, wounding thousands and killing 12 people.
The smallpox virus was a major killer until it was controlled with vaccinations in the 20th century. It has been eradicated in the natural world, but some fear terrorists could use laboratory strains as a biological weapon.
Anthrax is a bacteria.
Foot-and-mouth disease has recently been a huge problem in Europe. Spreading the disease to the United States would be relatively easy and very disruptive.
Most municipal water systems use chlorine today to kill bacteria. It's easy to manufacture from common table salt.
Many chemical weapons use ingredients found in insecticides. When you spray your lawn or garden with insecticide, you're basically waging a chemical war against backyard bugs.
In the 18th century, American Indians were infected with smallpox through donated blankets.
"The Rock" featured a scenario in which terrorists tried to launch a missile loaded with the chemical VX, a nerve toxin.