The lessons of Aum Shinrikyo

In 2008, a congressional commission warned of the threat that terrorists could acquire biological weapons. The technical obstacles would be large, probably beyond the capability of any existing terrorist group, the commission said in its report, "A World At Risk." But terrorists could recruit biologists. "In other words, given the high level of know-how needed to use disease as a weapon to cause mass casualties, the United States should be less concerned that terrorists will become biologists and far more concerned that biologists will become terrorists."

A fresh examination of the Aum Shinrikyo cult in Japan offers some insights into just how difficult it might be to use pathogens for terrorism. The Center for a New American Security has published a case study on the 1990s quest for biological and chemical weapons by the group. The report shows how cult leaders struggled to create a biological weapon and failed, and only then turned to a chemical weapon, which they managed to create, launching a sarin attack on the Tokyo subway in March 1995 which killed 13 people and injured many scores. The sarin attack–and reports that Aum experimented with biological substances–shocked the world, and is one of the events, along with the 2001 anthrax letters, which ramped up attention and public spending to combat biological terrorism. Billions of dollars have been spent in the last decade to defend and protect against a possible attack.

The new study, led by former Navy Secretary Richard Danzig, chairman of the board of the think tank, is based on prison interviews with some but not all of the Aum members. While the Japanese police investigations focused on developing court evidence about the sarin attacks, Danzig and his team sought to understand Aum as a terrorist organization and the choices they made about biological and chemical attacks. One thing they discovered was that Aum turned to chemicals because they were more accessible and easier than biological methods for mass killing.

The report shows how the cult slid into violence under the leadership of founder Shoko Asahara. After losing a parliamentary election bid in February, 1990, Asahara ordered his deputies to obtain some Clostridium botulinum, the bacterium that produces the dangerous botulinum toxin. In keeping with the cult’s belief in self-reliance, rather than purchase it under the guise of research, which was possible, the cult member overseeing the effort, Seiicho Endo, attempted to harvest the bacterium from soil. He tried two propagate it in cube-shaped fermenters. While it is not known exactly how much was made, apparently there was a large supply of the yellow liquid, comprised mostly of growth media. No attempt was made to separate the toxin from the media. (Endo refused to be interviewed by the authors of the study.)

All signs are that the "weapon" didn’t work. The cult used three trucks and tried to spray the stuff at two U.S. Naval bases, Narita airport, the Japanese Diet, the Imperial Palace and the headquarters of a rival group. No one died in their attacks. The attacks went entirely unnoticed. One member of the cult slipped and fell into a fermenting tank, and nearly drowned–but did not die of the disease.

Why did Aum fail? According to the report, there are many possible factors. Among them: they may not have acquired the right strain of the bacteria; they may have screwed up the culture conditions; they may not have fermented it properly to produce the toxin. All of this means that, thankfully, the Aum Shinrikyo biological "weapon" was no weapon at all.

After a pause, the cult resumed seeking a bioweapon in 1992. This time, Endo turned to Bacillus anthracis, the bacterium that causes anthrax. It is not known exactly how Endo acquired it, but he wound up with an extremely common and benign vaccine strain, perhaps from a university. The Danzig team speculates that he may have been attempting to add a plasmid necessary to make it an effectively virulent anthrax bacterium. This also failed. Some cult members inadvertently inhaled some of the product and did not fall ill. The cult attempted to disseminate what they had created using a homemade sprayer. At one point, mechanical difficulties made it "spout like a whale," one cult member recalled. The mixture was a foul-smelling brown liquid slurry. The cult members tried to add perfume to kill the putrid odor. No one died from it.

The report concludes that "this unbroken string of failures with botulinum and anthrax eventually convinced the group that making biological weapons was more difficult than Endo was acknowledging." That’s when they turned to chemicals and the sarin, which was placed in small bags which the cult members punctured on the Toko subway in March, 1995, leading to deaths and panic.

It seems clear from the Danzig study that the cult was limited by the capabilities of its members. They were a gang that couldn’t shoot straight when it came to biology. Their intentions were evil but in the end, despite funds and determination, they could not make a biological weapon. Instead, they killed with chemicals. Al Qaeda also looked into anthrax, but was never able to create a weapon. The Danzig study is about events of the past, but raises anew a question for today: whether terrorists can or will eventually succeed where the Aum Shinrikyo could not. It is a sobering thought.

The study does not deal with today’s biological threats. But it ends on a note of warning:

Groups such as Aum expose us to risks uncomfortably analogous to playing Russian roulette. Many chambers in the gun prove to be harmless, but some chambers are loaded. The blank chambers belie the destructive power that the gun can produce when held to the head of a society.