PHILADELPHIA (AP) - At secret locations in at least 31 cities,
the government has deployed devices that scour the air for deadly
agents like anthrax and smallpox with hopes of sniffing out
bioterrorism. But the effort has been viewed with skepticism.
Some security experts said the system is unlikely to catch a
bioterrorism attack in time to save many lives. And they said it is
powerless to spot an attack in an enclosed area, like an airport
terminal or subway line, and unable to detect attacks unless they
are big enough to scatter over several blocks.
"If you saw planes going over and releasing major clouds of
this stuff, there's a chance that people would get suspicious a
long time before anybody checked the filters," said Jacqueline
Cattani, director of the Center for Biological Defense at the
University of South Florida.
The sensors have been in place since early spring, and while the
government won't say exactly where, regional health officials
confirmed the list includes Philadelphia, New York, Washington, San
Diego, Boston, Chicago, San Francisco and St. Louis.
The White House in January said the "Biowatch" monitoring
system would cost about $1 million annually per city.
In participating cities, filters within the machines are removed
daily and immediately analyzed for spores and chemicals that could
have been dumped from a plane or building and left to drift in the
If an attack was close enough to a sensor, authorities could
know about it within 12 hours, according to Bob Bostock, homeland
security chief for the Environmental Protection Agency. That is
much faster than it would take people exposed to anthrax to develop
symptoms, he said.
"The main advantage or having a system like Biowatch is that
prior to it being rolled out, the only real way to tell if a
biological agent had been released was to see if people started
turning up sick or worse," Bostock said. "By knowing in advance
that a contaminant has been released, you can start treating it
before symptoms develop."
Much about the system is being kept secret; The government won't
say who makes the detectors, how much they cost, or what they look
like. Officials also won't say which labs are analyzing the
detectors' filters, other than to say that some are operated by
state health departments.
If a filter tests positive for a particle, scientists can
estimate where it came from, based on its physical properties,
Bostock said.
The system, though, has plenty of critics.
Calvin Chue, a researcher at the Center for Civilian Biodefense
Strategies at Johns Hopkins University, said the cost of testing
and replacing the filters daily will be high and the probability of
spotting a contaminant low. He also said the results will be
difficult to confirm, especially in polluted cities or places where
natural organisms found in the air can give false-positive results.
Researchers who studied what would happen if someone dropped 2.2
pounds of anthrax from a tall building in New York said the sensors
could save lives, but only if officials detected an attack
immediately and instantly began distributing medication.
Stanford Business School professor Lawrence Wein said in that
scenario, the number of dead could be cut from 120,000 to 70,000 if
sensors detected an attack within six hours. He said deaths could
be cut to 50,000 if the government allowed people to stockpile
antidotes ahead of time.
Bostock, of the EPA, wouldn't discuss how the detectors have
performed so far, but he said the monitors have neither detected an
attack, nor produced the type of false-positive reading that
triggers an emergency response.
"We have a high degree of confidence in the results we have
been getting," he said.
The EPA, he noted, has used similar sensors to monitor air
pollution for decades.
"It's not like, with a sensor like this, you have to have one
on every street corner," he said. "We have quite a bit of
experience in terms of how things move in the air."
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(Copyright 2003 by The Associated Press. All Rights Reserved.)