Two weeks after the start of the nation's worst biological attack, the federal government has no central inventory of dangerous disease cultures maintained by academics and private labs. Bacteria and viruses commonly are exchanged in informal arrangements. And researchers aren't required to track their stocks or report losses.

These lax controls make the nation's universities, health agencies and laboratories easy targets for would-be biological terrorists. A 1999 bill that would have closed many of these gaps was supported both by the Clinton administration and many congressional Republicans. But the legislation died amid strong opposition from universities.

"The minimal federal controls in this area would come as quite a surprise to most Americans," former representative Tom Bliley, R-Va., told a House committee two years ago.

"We permit anyone in this country -- including felons, foreign nationals from sensitive countries and members of extremist groups -- to lawfully possess even the most deadly biological agents, including anthrax, the plague and the Ebola virus. They don't even have to notify or register with any federal agency or gain government approval to get them."

It is not yet known whether the anthrax spores unleashed on Washington, New York and Florida since Sept. 11 originated in the United States or abroad. Also unclear is whether the finely milled, apparently sophisticated form of the bacteria was created in a military weapons lab or by a maverick scientist working for terrorists or alone.

Bush administration officials on Friday said any number of trained scientists could have produced the powdery spores that contaminated the office of Senate Majority Leader Tom Daschle, D-S.D. White House spokesman Ari Fleischer said the analysis of the material "indicates that it could have been produced by a Ph.D. microbiologist (and) that it could be derived at a small, well-equipped microbiology lab."

Such a renegade scientist would not have had to travel far for the microbes themselves, thanks to procedures and practices that make acquiring dangerous pathogens easy.

The World Federation for Culture Collections, a global registry of microbe and tissue cultures, lists 46 countries with active stocks of Bacillus anthracis, the bacteria that causes anthrax. Within the United States the number of labs with anthrax cultures is believed to number in the hundreds, spread across universities, private labs, hospitals, veterinary clinics and public health agencies. The exact figure is not known because the government does not keep an inventory.

"If you already have it, you don't have to register it," said Michael Allswede, associate professor of emergency medicine at the University of Pittsburgh.

Before 1997, there were few controls on even the most dangerous microbes. Numerous U.S. labs sold seed stock for anthrax and other potential "biological agents" to countries now on America's list of states that sponsor terrorism -- with the full knowledge and backing of the U.S. government.

Under the 1996 Anti-Terrorism Act, anyone intending to send or receive the most dangerous microbes is required to register with the federal Centers for Disease Control and Prevention and to demonstrate a legitimate scientific or medical use for the material. But the law left enormous gaps, according to terrorism experts and many public health officials.

Since the Sept. 11 attacks, several universities and government agencies around the globe have begun tightening security. For example, the U.S. Department of Agriculture this month launched a snap investigation of all veterinary labs that produce livestock vaccines, to determine which ones possessed anthrax spores.