The bacteria lie dormant, freeze-dried in sealed ampules, in a refrigerator on a teeming university campus beside the Nile.

They're among Earth's most common germs — clostridia perfringens (search), a cause of food poisoning, a specimen for research.

But this pathogen can also be a weapon: Iraqi scientists worked for years to mobilize this "Agent G" for Saddam Hussein's wars.

• This is Part II of a three-part series. Click here to read Part I.

In an America nervous over bioterrorism, new laws clamp controls on clostridia and other "select agents," demanding registrations, reporting, background checks on scientists.

Egypt, in a region roiled by terrorism, has no such laws, although the bacteria at Ain Shams University (search) are kept in a locked refrigerator, accessible by one authorized technician, in a laboratory protected by foolproof electronic keys, said Nabil Magdoub, microbe collection director.

"We have to be alert," he said, but not "unreasonable."

After all, Magdoub said, any hospital is also rife with dangerous microorganisms.

"The American people have become so sensitive towards a lot of normal, ordinary matters," he said, echoing a sentiment heard increasingly in America, where microbiologists fear that ever-stricter controls might stifle their ability to exchange samples and conduct research.

Four years after the Sept. 11 attacks, terrorist use of disease agents to inflict mass casualties looms more and more as the bottom line of America's sum of all fears. Tom Ridge (search), former homeland security secretary, has said authorities don't believe terror groups can build nuclear bombs, and so bioweapons (search) become the greater threat.

"Anthrax is a concern," said Donald Van Duyn (search) of the FBI's Counterterrorism Division. "You could do as much damage with anthrax and other substances" as with a nuclear bomb, the FBI analyst said in a Washington interview.

One attack scenario now used in U.S. planning sees more than 300,000 people in an American city exposed to aerosolized anthrax bacteria spread by terrorists via a truck sprayer, with more than 13,000 dying.

The fear is reflected in the U.S. budget's bottom line as well: Spending on civilian "biodefense" has leaped 18-fold since 2001, to $7.6 billion this year. Project Bioshield (search), to develop bioterrorism countermeasures, awarded its first contract last November, $877 million for 75 million doses of a new anthrax vaccine.

The anthrax scare began when someone mailed anthrax powder (search) through the U.S. postal system in late 2001 and five people died.

As a result, "I'd say we get five white-powder threats a week, people calling saying, 'I found white powder. What do I do?'" said Van Duyn.

Because of the high quality of those 2001 anthrax spores, however, experts believe the perpetrator, still at large, was not linked to foreign terrorists, but possibly to the U.S. government's own anthrax program. That research began decades back as an offensive weapons program, but is now considered defensive.

Even a terror group as well-financed and educated as Japan's Aum Shinrikyo (search), whose homemade sarin chemical agent killed 12 people in 1995, failed to isolate a virulent strain in four years' work on anthrax.

Usama bin Laden's Al Qaeda also pursued anthrax in Afghanistan, captured documents showed. But it turned the job over to a Malaysian with a mere bachelor's degree in biology, U.S. investigators found. He, too, apparently failed to find a virulent strain — let alone a workable way to "weaponize" anthrax — before being arrested in 2001 after returning to Malaysia.

Drying and refining anthrax spores into particles readily inhaled, and then engineering equipment to spread them extensively, is a formidable challenge, U.S. congressional researchers noted in a 2004 study.

"Even a Ph.D. microbiologist doesn't know the dark arts of putting microbes into weapons," said Jonathan Tucker, a bioweapons expert with California's Monterey Institute for International Studies.

It took Iraqi scientists five years to weaponize anthrax in the 1980s. Meanwhile, others in Saddam's secret program were working on "Agent G," U.N. arms inspectors later learned. The toxin-spewing clostridium perfringens, applied to shrapnel, would kill the wounded by spreading virulent gas gangrene in their shrapnel wounds.

The Iraqis apparently never weaponized Agent G, however, and eventually reported to inspectors they had destroyed all 900 gallons they made.

Today clostridium perfringens is one of 49 microbes on the U.S. list of "select agents" considered potential "severe threats." American laboratories handling the germ must register with the government, their personnel must undergo background checks, and transfers of cultures must be reported.

That list's length, from the toxin abrin (search) to the plague bacteria yersinia pestis (search), tells some that billions of U.S. dollars won't go far, since only three on the list — anthrax, smallpox (search) and botulinum toxin (search) — are being addressed so far in stepped-up biodefense research programs. And that's not counting any new genetically re-engineered microbes.

"What's going to come at you is impossible to predict," molecular biologist Roger Brent (search) told a U.S. House panel in July.

Others question whether anything will come, in view of what Tucker calls Al Qaeda's "gap in technical sophistication."

Milton Leitenberg, a bioweapons authority at the University of Maryland, contends the threat has been "systematically exaggerated."

Few question the need, however, to tighten security at microbe collections worldwide. Only 500 of the estimated 1,500 major repositories — which maintain, exchange and sell samples for research and diagnostics — subscribe to the World Federation for Culture Collections' voluntary security guidelines.

Magdoub's Egypt Microbial Culture Collection is one. But a team of Egyptian microbiologists noted in a recent study that smaller collections have proliferated in Egypt, which has no "biosecurity" laws.

Team member Youssef Hamdi told The Associated Press all such resources should be combined in a single "National Culture Collection" to "insure purity, conservation and security."

Internationally, "the problem is the ones you don't know about," said Barry Kellman (search), director of the International Weapons Control Center at Chicago's DePaul University. Perhaps one-third of the world's microbe collections are poorly protected, he estimated.

The World Health Organization plans a "guidance document" next year promoting laboratory biosecurity, but only individual governments can enforce restrictions.

Kellman, meanwhile, agrees with those who doubt that Al Qaeda, "in a cave in Afghanistan," poses a bioterrorism threat.

He worries more about a homegrown menace, asking, "What if Ted Kaczynski" — America's notorious Unabomber — "had been a biology professor instead of a math professor?"