HOMELAND INSECURITY
Expert: Bioterror threat overblown
No terrorist to date has had success aerosolizing lethal microbial agents, says Stanford's Wilkening

By Paul Sperry
© 2001 WorldNetDaily.com

WASHINGTON – If you're planning to buy a gas mask, as many nervous New Yorkers already have, you might want to save your money.

Despite media noise, the chances of terrorists attacking America with biological weapons are slim, say leading biowarfare experts. And even if terrorists do try to spread lethal microbial agents here, they'll likely fail.

What if they succeed? Well, a mask won't do you much good anyway – not unless you wear it all the time.

Experts say it's hard to effectively "weaponize" deadly bugs such as anthrax – which is not contagious, as many assume. It's even harder to produce large casualties, given the weather and other factors.

"It's not that easy to release biological agents so that they are infective, so that they can be inhaled," said Dean A. Wilkening, a physicist who heads a working group on biological terrorism at Stanford University's Center for International Security and Cooperation.

Wilkening, former director of the National Defense Research Institute, explains that terrorists have to find a way to disperse live bugs in a wide plume, and at the same time keep them alive. Blowing up a vat of anthrax, for example, will more than likely kill the bugs.

"It's harder to make these things work than is commonly assumed," he said in an interview with WorldNetDaily. "And many scenarios that are currently being discussed probably would not work."

What about spraying the bugs in the air?

Mohamed Atta, the late ringleader of the 9-11 attacks, reportedly looked into chartering crop-duster planes, leading some officials to believe Islamic terrorist cells may have plotted to use the planes to spray cities with deadly biological agents.

But experts say the spray nozzle on a crop duster wouldn't likely work as an effective respirable aerosol, because it takes a very fine mist to infect people with such spores.

And terrorists have had no luck using other spray devices.

Consider Japan's Aum Shinrikyo cult, for one.

On eight separate occasions between 1990 and 1993, Aum Shinrikyo tried to spray anthrax and botulinum toxins from trucks and rooftops in Tokyo, and each time it failed. No one was infected, or at least no one died.

Main reason: The terrorists had problems developing effective spray nozzles for aerosolizing the agents in the 1 to 5 micron range necessary for them to lodge in the lungs.

The Iraqis, who manufactured relatively large batches of anthrax and botulinum toxin, also had trouble developing efficient spray nozzles, settling instead on explosive release.

They had a program to add a payload of wet anthrax or botulinum toxin slurry to the warheads of their Al-Hussayn, or "Scud," missiles. But after the Gulf War, U.N. inspectors found their biowarfare production facility and blew it up with demolition explosives.

The lethality of such airborne attacks depends largely on the size of the particle dispersed, Wilkening notes.

Particles in the 1 to 5 micron diameter deposit efficiently in the lungs, while submicron particles tend to be exhaled. Particles above 5 microns tend to become trapped in the upper respiratory tract, where higher doses are required to start an infection. Those above 20 microns in diameter tend to settle to the ground quickly and, as a result, do not travel far downwind.

Of course, such hurdles don't mean terrorists couldn't overcome them. If so, the results could be far more devastating than the World Trade Center attack.

Pray for rain

A biological strike on Los Angeles or New York using efficient devices spraying several tens of kilograms of anthrax, for example, could result in up to 100,000 fatalities, experts figure. If the attack is targeted, say, on the busiest streets of Manhattan – at lunchtime, on a clear day, with a temperature inversion trapping agents close to the ground – deaths could be in the millions, which is about what you'd expect from a nuclear bomb.

Thankfully, weather is another thing terrorists have going against them.

While anthrax spores are resistant to heat and dryness, they're no match for rain. A downpour would wash most of them out of the air, where they'd become relatively harmless.

Also, humidity and ultraviolet light decay the bugs. So does oxygen. Anthrax and botulinum spores multiply in the absence of oxygen.

Besides the weather, terrorists bent on mass killings also would have to make sure deadly clouds catch people outdoors.

If you're in a environmentally controlled office building with sealed windows, the integrated dose of toxins you'd receive from a cloud passing over your building would be reduced by a factor of 10 or more, estimates bioterror expert Lester L. Yuan.

The higher the quality of air filters in the heating, ventilation and cooling system, the less the exposure. The best filter for screening out such lethal spores is a medical filter known as a "HEPA" filter, experts say.

If you're in your house with the doors and windows closed, your in-take would be cut by a factor of two or more, Yuan says.

What about dumping bugs in the water supply?

The terrorists reportedly showed an interest in trucks that haul hazardous waste, leading cities to tighten security at reservoirs.

Passing on reservoirs

Anthrax bugs can also be delivered in the form of liquid slurries. Gastrointestinal anthrax is rapidly fatal in many cases.

But experts say reservoirs aren't an attractive target for terrorists, because they'd have to dump large amounts of biological agents to overcome dilution. Also, water supplies are filtered and chlorinated to kill naturally occurring microorganisms, which would neutralize anthrax and other bacteria.

"These threats tend to lack credibility," Wilkening said.

In fact, terrorist contamination of water supplies is extremely rare, according to a study of such cases by Jessica E. Stern, author of "Would Terrorists Turn to Poison?"

Those still worried may want to buy purified bottled water.

For these reasons, biowarfare is not a popular method of attack by terrorists.

Aum Shinrikyo is the only example of a terrorist group using biological or chemical weapons for mass murder. The cult ended up turning to sarin gas to attack Tokyo subway commuters, killing 12 and hospitalizing about 1,000.

In fact, threats or actual use of chemical or biological weapons account for only 52 cases out of more than 8,000 in the RAND Chronology of International Terrorism since 1968.

Many are just scares. Wilkening counts more than 120 anthrax hoaxes alone which have been reported in the media nationwide since October 1998.

"Except now" with the boldly brutal al-Qaida cell, Wilkening cautioned, "we have a group that demonstrated that they're willing to commit mass murder with no clear political objectives."

Livestock cover story

In fact, Defense Secretary Donald Rumsfeld and other administration officials recently have said that the threat of a biological attack is quite real (although some speculate such warnings may also serve to head off another political embarrassment. The U.S. intelligence community was blind-sided by the jetliner attacks).

It's not easy to detect biowarfare labs, since growing the bugs doesn't require big facilities. Iraq had a modest-sized production facility, which escaped U.S. notice and targeting during the 1991 war.

Export control of equipment is also tough. Fermenters widely used for medical research can also be used to grow lethal microbial cells and viruses. States can say they want such vats for vaccine production or agricultural purposes. China got such equipment through President Clinton's fund-raiser pal Yah Lin "Charlie" Trie, for one. Trie, convicted of fund-raising violations, told the FBI that scientists there wanted it for a vaccination program. Iraq got equipment by saying it was making single-cell protein for livestock feed.

Some officials say bin Laden could have a lab set up in Germany, or even here in the states.

However, it's more likely that if bin Laden has access to bioweapons he is a beneficiary of programs sponsored by foreign governments which can provide needed capital, equipment, facilities and scientists.

Wilkening says a terrorist weapon, if developed, would be small and unlikely to cause a million casualties. He says 10,000 to 50,000 is more realistic – and only if they've perfected the weaponization technology, which is doubtful.

Anthrax and botulinum, as bacteria that multiply rapidly and create toxins that injure the body, are the classic biological agents.

Of the two, anthrax is potentially deadlier. Pulmonary anthrax, caused by inhalation of anthrax spores, causes severe lung inflammation that can be fatal in 18 to 48 hours if untreated with large amounts of antibiotics.

As biological agents, they are odorless, colorless, tasteless and hard for air-quality sensors to distinguish from other airborne biological particles such as pollen, although new research may provide means to detect them in the future.

Not contagious

Much of the panic now is based on an irrational fear that anthrax and other potentially deadly bacterial spores could spread far beyond the release zone, as people travel during the incubation period and come in contact with others.

But most toxins, including anthrax, are not contagious.

"Anthrax doesn't spread," Wilkening said.

"Almost all biological warfare agents that are in the programs of various states – the U.S. historical program, the Russian one, the Iraqi one – are not contagious," he said.

Reason: On the battlefield, you don't want them to spread to your own troops, or your own population.

However, the small pox virus is contagious, highly so, and it recently was brought back onto the list of possible biological agents.

There have been revelations that the Russians, in their covert biowarfare program, have weaponized small pox. And there have been recent reports – one in the Washington Times quoting unnamed intelligence sources – that the Russian mafia may have supplied Osama bin Laden and his terrorist al-Qaida terrorist network with components for biological weapons.

"But we've had small pox outbreaks, small ones, and they have not spread that much," Wilkening said. "They've been able to contain them."

And millions of American adults, including baby boomers, have already been vaccinated against small pox.

But some have speculated that a small pox broth sprayed into the ventilation system of a major international airport would, within 24 hours or so, cause an epidemic to break out across the world, making the virus harder to contain.

Small pox vaccine?

Rolling out a national small-pox vaccination program to immunize every American as a prophylactic against such a biological attack may not be feasible right now – not only because of cost and a lack of virus stores to remanufacture the vaccine – but mainly because of the unnecessary risk of adverse medical reactions among otherwise healthy Americans, particularly children. It may not be worth the risk unless, or until, there's solid evidence that a terrorist group possesses a small pox weapon.

Constant TV media coverage has whipped Americans into a panic over a possible biowarfare attack.

Hysteria has prompted big city-dwellers to empty store shelves of respiratory masks.

But such masks offer a false sense of security, experts say, because people won't know when to put them on.

Buying antibiotics won't help much, either, since people won't know which antibiotic they'll need, or when to take it.

Many who argue that the bioterror threat is overblown advise Americans to stay alert, yes, but calm.

"People are very scared these days, and we don't want to exaggerate the likelihood or the consequences of a possible biological attack," Wilkening said. "But we should still be vigilant."

Paul Sperry is Washington bureau chief for WorldNetDaily.