Anthrax is hardly the only biological weapon, which range from directly infectious bacteria to toxin-producing microbes. The U.S. and Russia both had research programs to weaponize organisms in previous decades[OR: during the Cold War], as did other countries. Although banned by international treaty, some nations continue to develop and/or stockpile them, according to the Arms Control Association. But complicated technology is not required to wreak this type of havoc; cult leaders in Oregon infected local salad bars with diarrhea-causing salmonella in a bid to influence an election in 1984.
6. DIRTY BOMB
The U.S. has spent the past several decades turning old Russian nuclear warheads into nuclear fuel for its own reactors—along with installing more security at Russia's remaining nuclear weapon sites—thereby diminishing the threat of nuclear apocalypse. But some critics, such as journalist William Langeswiesche, have noted how the remaining Russian arsenal remains vulnerable to theft or sale. The idea may not be to launch a full-fledged nuclear bomb assault but rather to create a so-called dirty bomb—a conventional chemical explosive packed with radioactive material that can be detonated in any number of ways and sizes.
Such a bomb would likely directly kill only those caught in its initial explosion but—as the recent meltdowns at the Fukushima nuclear power plant in Japan show—fear of radioactive contamination might spur panic.