While many experts believe a terrorist attack on the United States with chemical or biological weapons is inevitable, policymakers should consider the difficulties involved in making chemical and biological weapons, compared to conventional explosives.

According to a recent study by the Henry L. Stimson Center, from 1980 to 1999, the State Department reports 9,255 terrorist attacks worldwide. Most of these attacks were with conventional arms or bombs. Only 342 cases of chemical or biological terrorism have occurred worldwide over the past quarter-century. In these:

• Three or fewer people were killed or injured 96 percent of the time.

• Sixty percent of the time, no one was killed or injured.

• Since 1975, worldwide there have been 154 fatalities from "chemical terrorism."

• No one in the United States was killed by either chemical or biological attacks.

According to the Stimson report, "[t]errorists...are likely to find it quite difficult to obtain and use biological and chemical weapons effectively."

For example, the Japanese cult Aum Shinrikyo spent an estimated $30 million on its chemical weapons program, and targeted of graduate students and other well-trained scientists for recruitment. Yet their 1995 sarin gas attack on the subway in Tokyo killed only a dozen commuters, about 40 others were seriously injured, and slightly less than 1,000 were made "moderately ill."

Obtaining lethal chemicals or isolating lethal strains of biological material is only the first hurdle would-be attackers must clear.

• Ninety-percent of any agent sprayed outdoors will not reach its intended targets.

• Most bomb detonations would kill a bioweapon and destroy chemical agents.

• Explosive devices often fail to effectively disperse bioweapons and chemical agents.

By contrast, the Oklahoma City and World Trade Center bombings showed terrorists can manufacture conventional bombs at a relatively low cost and with limited expertise.

Source: Vernon Loeb, "Making Chemical Weapons Is No Easy Task," Washington Post, February 5, 2001; "Ataxia: The Chemical and Biological Terrorism Threat and the U.S. Response," Henry L. Stimson Center, 11 Dupont Circle, N.W., Ninth Floor, Washington, D.C. 20036, (202)223-5956.

For Washington Post text http://www.washingtonpost.com/wp-dyn/articles
/A19900-2001Feb2.html

For study http://www.stimson.org/cwc/ataxia.htm