May 26, 1998

May 26, 1998 | Backgrounder on Department of Homeland Security

Microbes and Mass Casualties: Defending America Against Bioterrorism

Throughout human history, the threat of mass contagion has evoked primal fear. Natural pestilence periodically has ravaged cities, states, and even entire civilizations. Rapid advances in genetic engineering in the past few decades have increased the likelihood that disease-causing microbes could overwhelm the U.S. public health system and wreak horrific destruction. Today, the United States faces the nightmarish possibility that terrorist groups would seek to cause mass casualties by unleashing biological agents on U.S. soil.

Biological agents, on an equal-weight basis, are the most lethal substances known to mankind. According to a 1997 U.S. Department of Defense report on proliferation, the "most lethal biological toxins are hundreds to thousands of times more lethal per unit than the most lethal chemical warfare agents."2 They can be targeted against people, animals, or crops using a variety of means of delivery, from aerial bombs and spray tanks to ballistic missile warheads.3

Until recently, the intelligence community generally has downplayed the capability of terrorists to effect mass casualties using biological agents, noting that the impact of an attack is difficult to predict, considering the sensitivity of microorganisms to meteorological conditions. Most analysts agreed with the view that terrorists only "want a lot of people watching, not a lot of people dead."4 But the 1993 World Trade Center bombing, the 1995 sarin attack in Tokyo`s subway system, and the 1996 Oklahoma City bombing shattered that conventional wisdom. These attacks indicate an important threshold has been breached; clearly, some terrorist groups want a lot of people watching and a lot of civilians dead.

Belatedly, senior defense and law enforcement officials are recognizing the growing danger of bioterrorism. Gordon Oehler, then director of the Nonproliferation Center of the Central Intelligence Agency (CIA), testified before Congress in March 1996 that

Extremist groups worldwide are increasingly learning how to manufacture chemical and biological agents, and the potential for additional chemical and biological attacks by such groups continues to grow.5

In January 1998, Defense Intelligence Agency chief Lieutenant General Patrick Hughes testified that chemical and biological weapons have a "high probability of being used over the next two decades."6

Despite this awareness, the United States still is ill-prepared to manage the consequences of a major bioterrorist strike. Deputy Secretary of Defense John Hamre admitted last December, "We are not currently equipped to handle a widespread terrorist attack that would involve biological weapons."7 A March 1998 bioterrorist exercise involving government officials from more than a dozen federal agencies considered the impact of a deadly virus along the U.S.-Mexico border. This simulation predicted such an attack would cause thousands of deaths and widespread panic. The exercise also revealed the inability of local and state officials to cope with a major bioterrorist strike and highlighted a disturbing lack of interagency coordination among federal officials.8

The conventional military prowess of the United States is not sufficient to offset the danger posed by bioterrorism. Secretary of Defense William Cohen noted in March 1998,

Our American military superiority presents a paradox...because our potential adversaries know they can't win in a conventional challenge to the U.S. forces, they're more likely to try unconventional or asymmetrical methods, such as biological or chemical weapons.9

Clearly, the Clinton Administration and Congress must develop and articulate a comprehensive strategy to defend against bioterrorism that is based on an accurate assessment of threat, the prudent allocation of resources, and a determined respect for the rule of law. If properly implemented and sustained, such an approach would help deter terrorists and the sponsors of state terrorism who otherwise might consider biological attacks on U.S. citizens.


Biological agents, which include disease-causing microorganisms called pathogens and poisonous chemicals produced by microorganisms called toxins,10 are pound for pound the most lethal substances known to mankind. They can be targeted and delivered against innocent people, as well as their food or water supply. And the means of delivery ranges from sprays and bombs to ballistic missiles.11 The young, the elderly, and the infirm are especially vulnerable to bioterrorism's insidious reach because of their weakened immune systems.

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