Anyone who takes seriously an “orange alert” from the Department of Homeland Security may be comforted by Tom Ridge’s new scheme to detect contagions drifting in the air within 24 hours of their release. Bio-Watch promises to give emergency workers the heads-up on bioterrorism attacks, long before victims are being packed into hospital wards. With the U.S. expecting retaliatory strikes should Bush order war against Iraq in coming days, officials want Bio-Watch to be a blanket of civilian safety.

Working with the Environmental Protection Agency and the Centers for Disease Control and Prevention, Ridge’s department is already slapping filters on EPA air pollution monitors nationwide to catch bits of anthrax, smallpox, “and a number of other agents that we’re not talking about,” said Tom Coda, an EPA program coordinator. Labs certified by the Centers for Disease Control will test the filters daily for the presence of infectious agents.

Sounds like a plan. But before preparedness freaks pull the duct tape off their windows, they should first hear what independent scientists think about Bio-Watch.

“It’s crazy,” said Jacqueline Cattani, director of the Center for Biological Defense at the University of South Florida. “We don’t see how random air sampling can cover a large area effectively. To pick up a potential exposure to a biological agent by air monitoring or other sensor-type technology, you’d have to be extremely lucky.”

The U.S. Army-funded center is instead gathering Web-based reports on disease patterns from health care workers at 13 hospitals, military bases, and amusement parks throughout central Florida. It’s a pilot project, but one that scientists consider to be a model for the early detection of bioterrorism attacks.

Kristin Broome Uhde, an epidemiologist who works for Cattani, spends much of her time eyeballing the secure, real-time reporting system for signs of a bioterrorism attack. “We’re looking for outbreaks of nonspecific illnesses or symptoms,” said Uhde. “That’s how diseases like anthrax and smallpox present themselves, with flu-like symptoms.”

While real-time databases should detect any type or level of attack, Bio-Watch is designed only “to detect large-scale bioterrorism attacks,” said Coda.

Scientists have speculated that a refrigerated warhead bearing smallpox, or an aircraft releasing large amounts of aerosolized bacteria, might affect a big area. But an effort like that would start with a major event seen by hundreds or thousands of people, so Bio-Watch is unlikely to provide much of an early warning to anyone. “People will be getting sick long before the lab results are back,” Cattani said.

Bio-Watch also ignores the threat of small attacks, which seem much more likely than a crop duster seeding Fifth Avenue with anthrax spores. Experts think terrorists are more likely to release biotoxins with jerry-rigged portable devices and through other, “quieter,” events.

“A terrorist might infect himself with smallpox in a suicide attack, trying to infect as many other people as possible,” said Christopher Aston, adjunct assistant professor at the W.M. Keck Laboratory for Biomolecular Imaging at NYU Medical Center.

Even if small disease particles can reach the EPA monitors, many of which sit atop buildings, on the tops of long poles, the superfine Bio-Watch filters designed to catch them will have been rendered useless by the soot and dust they suck out of the air.

“Checking the filters once each day in Los Angeles, for example, is not going to be enough,” said Calvin Chue, a research scientist at the Center for Civilian Biodefense Strategies at Johns Hopkins University, in Baltimore.

Chue, who has been a bioweapons consultant to the U.S. Navy, the FBI, the Secret Service, and the United Nations Special Commission on Iraq (UNSCOM), also said Bio-Watch isn’t prepared for the frequent, perhaps hourly, trips that will be needed to avoid clogged filters. “They will also have to train personnel,” said Chue, “on how to maintain a property chain of custody, in case a filter becomes evidence for an FBI investigation.”

CDC-certified labs will also be hard-pressed to keep up with even daily testing of air filters from Bio-Watch. “They’re already overworked as it is,” the Center for Biological Defense’s Cattani said.

Scientists are likewise troubled by the Department of Homeland Security’s secrecy over Bio-Watch’s technology. “All we’re saying is that we’re using really powerful vacuums and really good filters,” said Coda, of the EPA. A CDC spokesperson would only tell the Voice that the filters for Bio-Watch were developed at labs run by the U.S. Department of Energy. And neither the CDC spokesperson nor Coda would say how the filters are being tested.

The government is afraid terrorists will engineer viruses and bacteria to thwart Bio-Watch’s technology. But “by couching projects in terms of homeland security, the [Department of Homeland Security] and other agencies avoid peer review,” said retired U.S. Navy commander Dr. William M. Nelson, president of Gaithersburg, Maryland-based Tetracore. His company makes bioterrorism detectors that are used by UNSCOM inspectors and designated early responders within the United States.

The risks of moving forward with a flawed program are many. Researchers are working on portable analyzers that will recognize biotoxins on the spot. But these devices are notorious for false positives, which could spark mass panic. “A false positive for anthrax is one thing,” said Nelson. “It’s not contagious, and you can treat it with antibiotics. But can you imagine what might happen with a false positive for smallpox? The disease is contagious. You’d have to shut down an entire city. The costs to businesses would be in the billions of dollars.”

The Department of Homeland Security plans to fund the development of standards for certifying the reliability of detection equipment. But while the agency may one day be more open about its technology, the EPA is just learning the art of secrecy, as it adjusts to its new role as a sentinel against bioterrorism.

Program coordinator Coda would say only that Bio-Watch is retrofitting EPA air monitoring sites in major population centers, “including New York and other cities.” He refused to name specific sites. But would-be saboteurs need only visit the EPA’s public Web site to find the precise addresses and descriptions of the agency’s existing air monitors, which can be found atop schools and federal buildings, among other locations.

The EPA’s searchable database, AirData, also includes such details as what individual monitors are filtering for, and when they were last inspected.

Communities sponsored by the EPA’s Environmental Monitoring for Public Access and Community Tracking (EMPACT) program, meanwhile, are posting maps and photographs of their air monitoring stations on the Web. “Most of the data for AirBeat comes from a new air monitoring station located on Harrison Avenue, two blocks east of Dudley Square,” reads the Web site for AirBeat, an EMPACT site in Roxbury, Massachusetts.

An EPA technician also spilled the beans to a community organizer about the Bio-Watch filters he’s adding to monitors in St. Louis. “The EPA hasn’t installed new filters on any of our monitors,” said the organizer, Emily Andrews, who works with the EPA-funded Community Air Project in St. Louis. “But my contact at the regional office told me he is retrofitting six or seven monitoring stations for Bio-Watch.”

Andrews’s EPA contact did not return a voice mail requesting an interview. Instead, a regional spokesperson in Kansas City, Kansas, Dale Armstrong, called back and confirmed that Bio-Watch is operating at several undisclosed EPA sites in St. Louis. “We’re now getting the message out to our people that they shouldn’t be discussing any details about Bio-Watch,” Armstrong said.