Despite U.S. efforts to change the situation, the threat of Soviet bioweapons remains. Research and production facilities in Russia and the New Independent States are poorly guarded and vulnerable to theft, says Kathleen Vogel of Cornell University. Moreover, Russia continues to deny access to four Ministry of Defense bioweapons facilities for inspection. "We have no proof, but there are concerns that Russia is restricting access to retain its biological weapons capability. We hope there are other reasons," Vogel reports.

Former biological weapons specialists in Russia and the New Independent States have received some U.S. funding to redirect their research for peaceful purposes. But Vogel, who spoke Friday at the annual meeting of the American Association for the Advancement of Science in San Francisco, notes that because of the unstable Russian economy, "you cant rule out people engaging in proliferation through temptation or corruption."

Scientists are particularly concerned about the possible theft of smallpox virus samples. The only official repositories for the virus, which was eradicated in 1980, are at the U.S. Centers for Disease Control in Atlanta and the State Research Center for Virology and Biotechnology in Koltsovo, Russia. But other facilities in Russia may hold the virus, too. Other worrisome microbes include genetically engineered strains of anthrax and plague bacteria that are resistant to Western antibiotics, as well as animal pathogens developed for use against agricultural targets.

According to Vogel, the most dangerous threat may come from the recruitment of former bioweapons scientists by scheming governments. "U.S. nonproliferation programs are essential," she asserts, "because we must make it more difficult for states to recruit these scientists and obtain their sophisticated bioweapons technologies and know-how."