FEATURE ARTICLE
The Growing Threat of Biological Weapons
The terrorist threat is very real, and it's about to get worse. Scientists should concern themselves before it's too late
Steven Block
Assessing the Terrorist Threat
Biological weapons have been called "the poor man's atom
bomb." By any measure, the economic outlay required to develop
offensive bioweapons capabilities is significantly less than that of
a nuclear program. Less is needed in the way of equipment and
infrastructure. The materials themselves are less rare. And less is
required in the way of specialized knowledge for the biological
aspects, since much of the information can be found in the public
domain. Worldwide, trained microbiologists overwhelmingly outnumber
nuclear physicists. All these aspects tempt not only nations of
concern, but also non-state actors. In fact, it seems far more
likely that biological agents will be used by terrorists than by
warring nations. Although the terrorist use of bioweapons is likely
to occur on a reduced scale, it could have worldwide ramifications
under unfavorable circumstances.
Little of real consequence has occurred along these lines, but shots
have been fired across the bow. In a bizarre episode that took place
in September 1984, more than 750 people fell ill with food poisoning
in The Dalles, Oregon. Thankfully, no one died. The cause of the
epidemic was not uncovered by health authorities at the time. But in
1986, Ma Anand Sheela confessed at trial that she and other
followers of the Baghwan Sri Rajneesh had spread salmonella
bacteria, grown on the cult's Oregon ranch, in salad bars in four
restaurants, all in an effort to keep voters from the polls so as to
influence a local election. After serving two and a half years in
federal prison, Sheela was released and deported to Europe.
Between 1990 and 1995, the well-financed Japanese apocalyptic cult
Aum Shinrikyo launched a repeated series of attacks on civilians
using both biological and chemical weapons. These culminated in the
infamous sarin gas release inside the Tokyo subway system in March
1995, which left 13 people dead and sent more than 5,000 to the
hospital. Before resorting to toxic gas, the group had reportedly
attempted, unsuccessfully, to mount attacks with biological weapons
on at least nine occasions over a five-year period. Aum Shinrikyo
boasted a dozen or so members with biological training and had even
gone so far as to buy a 500,000-acre sheep station in Banjawarn,
Australia to serve as a site for operations and to carry out tests.
The cult worked to develop biological weapons based mainly on
botulinum toxin and anthrax, although some members made an
unsuccessful trip to Zaire to obtain Ebola virus. They also
attempted, but failed, to acquire the rickettsia Coxiella
burnetii, which causes Q fever. In their earliest attempts to
carry out biological attacks, members of the cult sprayed
home-brewed botulinum toxin on Tokyo streets, near two American
airbases in Japan and at the Narita International Airport. All of
these attacks failed??most likely because they worked with the wrong
strain of C. botulinum (not all natural variants yield
equal toxicity) and because their misting device may not have been
up to the task. They later switched to anthrax, releasing spores in
Tokyo near the Imperial Palace, the legislature and a foreign
embassy. These tactics again failed, almost certainly because they
used a vaccine strain of B. anthracis. And again, their
spraying device may not have worked as intended.
Does this mean that we should all relax, because using bioweapons
turns out to be harder than the perpetrators thought? Is the
terrorist threat therefore exaggerated, as some have maintained?
Those who claim that biowarfare agents can be brewed in a garage by
practically anyone with a modicum of training may be guilty of
overstating the case, but although there has been no shortage of
exaggeration, that doesn't mean we're off the hook.
A lesson from the Aum Shinrikyo case is that any group bent on
developing offensive bioweapons capabilities must overcome two
significant problems, one biological and the other physical. First,
it must acquire and produce stable quantities of a suitably potent
agent. For a variety of reasons this is not the trivial task that it
is sometimes made out to be. Second, it must have an effective means
of delivering the agent to the intended target. For most, but not
all, bioweapon agents, this translates into solving problems of
dispersal. Programs in both the U.S. and the U.S.S.R. devoted years
of effort to perfecting these aspects.
But who is to say that a terrorist group might not find its own way
to imperfect solutions? After all, a terrorist works under entirely
different constraints. For one thing, there's no requirement for the
dispersal to be very efficient, because bioweapons terror attacks
are highly leveraged. If anthrax were released haphazardly in a
major U.S. city and produced only a handful of cases, the public
fear and disruption that would ensue might alone bring about the
intended effect. Our public health system simply isn't geared up to
handle an outbreak of this kind, which would, for a time, flood
emergency rooms. A terrorist group might also be tempted to finesse
the dispersal problem and release some contagious disease, with the
aim of starting an epidemic or even a worldwide pandemic. Or it
might choose to act covertly, perhaps attacking an economic target,
such as crops or livestock, rather than a human population. There
are many different options.
In my opinion, the terrorist threat is very real, and it's about to
get worse. And opinions do count here, because quantitative risk
assessment is a practical impossibility. As with nuclear war,
successful bioweapons attacks are characteristically "low
probability, high consequence" events. The expectation value of
the risk is the product of a very small and a very large number, and
such numbers carry great uncertainty.
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