At its peak, the former Soviet Union had the world's largest biological warfare program, with somewhere between 25,000 and 32,000 people employed in a network of 20 to 30 military and civilian laboratories and research institutions. An additional 10,000 or so worked in Defense Ministry bioweapons laboratories. According to other estimates, at least 47 labs and test facilities were scattered across Russia, employing more than 40,000 workers, 9,000 of whom were scientists. Betwen 1,000 to 2,000 of those scientists were experts on deadly pathogens. Biopreparat suffered dramatic downsizing after the dissolution of the Soviet Union in 1991, with more than half its scientific staff departing, many of whom left Russia for more sophisticated laboratories of the West.In 1989, the first defector to emerge from Biopreparat, Vladimir Pasechnik, revealed that the Soviet biological warfare effort was ten times larger than estimated by US or British intelligence. And in 1992 Dr. Kanatjan Alibekov (Ken Alibek) defected, providing new details of Moscow's extensive biological warfare development program. Other defectors, whose identities have not been disclosed, have provided additional information to Western intelligence agencies.