Experts argue over how hard it is for terrorists to make weapons of mass destruction, but a new study of the doomsday cult that carried out the Tokyo subway nerve gas attack says that even seemingly marginal groups can succeed with persistence and luck.
A report on the Aum Shinrikyo cult by ex-Navy Secretary Richard Danzig and colleagues at the Center for a New Security describes the cult's often bumbling efforts to make biological and chemical weapons in the 1980s and 1990s.
But the report says that the cult's persistence was key to its success in making sarin nerve agent, which it used in its deadly 1995 attack on Tokyo commuters that killed 13 and injured more than 6,000.
"Terrorists need time; time will be used for trial and error ...; trial and error entail risk and, in this case, provoked disruption; but Aum found paths to WMD, and other terrorists are likely to do the same," said the report.
Japanese authorities granted Danzig and his co-authors rare access to senior cult members being held in a Tokyo prison during a series of interviews that began in 2008.
Danzig told terrorism experts and others gathered to discuss the report Thursday that experts needed to understand the cult's quest for WMD in order to learn how to prevent others from doing the same thing.
Terror groups can seem "almost laughable" when they fail, Danzig said, and Aum Shinrikyo had many failures and setbacks. He cited one case where a cult devotee fell into a fermenting tank full of the bacterium that produces the botulinum toxin and nearly drowned. He was unharmed.
There was of course nothing funny about the group's successes, which included the subway attack and an earlier effort to use sarin gas to kill the judges in a commercial dispute involving the cult. The judges survived but eight people died in a nearby apartment building when the wind shifted.
Danzig compared the situation to Russian roulette. Terror groups trying to make WMD can keep shooting blanks, he said, "and then one of the chambers turns out to be loaded."
Danzig said the miniaturization of chemical equipment and the new synthetic biology, capable of producing disease-causing organisms, have only raised the risk that small groups can manufacture weapons capable of killing thousands.
But the report also said that the cult was never able to devise a way of disseminating its chemical and biological arsenal with any precision. Producing large quantities of these materials probably also remains a challenge.
The authors reported that the group struggled to make bioweapons, and it still isn't clear if it succeeded in producing deadly forms of anthrax or other pathogens. As a result, they concluded that it is probably much harder for terrorists to make biological arms than chemical weapons.
"As a rule of thumb, we think that conventional bomb makers who manufacture their weapons need days, chemists need weeks, biologists need months and nuclear terrorists need years," the study said.