Rosenau, William. "Aum Shinrikyo’s Biological Weapons Program: Why Did it Fail?". Studies in Conflict & Terrorism, Vol.24 (2001): 289-301.

Rosenau, William. "Aum Shinrikyo’s Biological Weapons Program: Why Did it Fail?". Studies in Conflict & Terrorism, Vol.24 (2001): 289-301.

• On 20 March 1995, the Aum Shinrikyo cult carried out a sarin gas attack on a Tokyo subway, killing 12 and injuring over 5,000 more. This was the first instance of a terrorist group using chemical weapons against civilians (289).
• Aum Shinrikyo had a number of chemical and biological weapons programs, and intended to launch a major biological attack. The group had been developing biological weapons since 1990 and had launched failed attacks against the Japanese imperial family and the US naval base in Yokohama (289-290).
• The repeated failure of these programs is important because they well-funded and lasted for a long period. Understanding why Aum Shinrikyo's four-year-long biological weapons program failed is important for understanding the limitations on non-state actors developing these weapons (290). 
• Aum Shinrikyo had massive financial resources, front companies that successfully purchased equipment necessary for the creation of biological agents, personnel with scientific background and training, and topnotch facilities (293).
• Aum Shinrikyo's biological weapons program began in early 1990, when Shoko Asahara informed his followers that armageddon was coming and that Aum Shinrikyo would need new weapons for the coming conflict. The group built a laboratory at its base in Kamikuishiki and Shoko Asahara ordered Endo Seiichi, a molecular biologist, to design a biological weapon (291).
• Endo Seiichi selected Clostridium botulinum, an organism that produces the botulinum neurotoxin, as the biological agent for the attacks. The bacterium is extremely common in soils and only small amounts of the toxin are needed to kill (291-292).
• The focus on biological weapons development was flexible; in October 1992, the group tried to acquire samples of the Ebola virus following an outbreak in Congo-Zaire. There were also discussions of using Q fever or poisonous mushrooms as biological agents, and these alternatives were apparently tested by poisoning dissent members of the cult (292).
• By April 1990, Mr. Endo had a sample of C. botulinum ready to test as a weapon. Aum Shinrikyo cultists sprayed the toxin into the air around the Japanese Diet, Yokohama naval base, and the Narita international airport. None of these attacks produced casualties (292).
• Aum Shinrikyo launched another failed attack using C. botulinum in June 1993 against the imperial family. After this failure, the group shifted its focus from C. botulinum to Bacillus anthracis, the bacterium that produces anthrax. They developed this capacity in a new lab in eastern Tokyo and apparently sprayed several samples into adjacent streets and around the imperial palace, but failed to kill anyone (292).
• In March 1995, Aum Shinrikyo abandoned its development of a B. anthracis agent and switched back to using C. botulinum. They planned to spray the agent into computer trains at Kasumigaseki station in Tokyo. The agent responsible for this attack purposefully sabotaged it, however. In light of this failure, Aum Shinrikyo decided to use sarin gas rather than a biological agent for the attack (292-293).
• The development of chemical and biological weapons by Aum Shinrikyo prompted a major transition in how the USA and other countries assessed terrorism. The USA has responded by training emergency services in how to respond to chemical, nuclear, and biological weapons attacks, funding a massive civil defense program, and focusing on how to control nuclear, chemical, and biological weapons (290).
• Aum Shinrikyo was founded in 1984 by Shoko Asahara, a former yoga instructor originally named Chizuo Matsumoto, who preached a syncretic religion based on Hindu, Shinto, Buddhist, and idiosyncratic beliefs. He preached that the corrupt world order would be destroyed and replaced with a utopia (291).
• Aum Shinrikyo managed to attract large numbers of alienated and well-educated young Japanese. At its height, it had between 10,000 and 60,000 members and assets totaling between $300 million and $1 billion. Discipline was enforced on the membership through beatings, isolation and confinement, psychological torture, and dosing with LSD (291).
• Endo Seiichi failed to acquire the proper strains of C. botulinum and B. anthracis needed to kill humans. Only certain strains of both bacteria actually produce toxins that harm humans; it appears that Aum Shinrikyo actually created a harmless variety of B. anthracis in its labs. The lack of scientific training in the Aum Shinrikyo program, including Mr. Endo himself, likely contributed to the failure of these initiatives (293-294).
• The weaponization of C. botulinum, in particular, is very difficult, as the bacterium needs to be cultivated in large amounts to produce enough toxin. Moreover, that toxin needs to be pure to be effective as a biological weapon. Botulinum, however, degrades rapidly, a trait that led it to be rejected by American scientists for use the US biological weapons program (293-294).
• The distribution of these biological agents as weapons also posed problems for Aum Shinrikyo. The dispersed sprays they used would have lacked the concentration required to poison large numbers of people. The more effective distribution method of powered anthrax is costly to produce -- requiring expensive centrifuges -- and exposes its distributors to a high risk of infection themselves (294-295).
• Aum Shinrikyo's specific tactic of developing slurries containing anthrax or botulinum and then atomizing those into an aerosol spray was particularly ineffective, since the rapid changes in pressure, temperature, and sudden exposure to atmosphere result in the death of over 90% of the biological agents. Moreover, the aerosol cloud leaves the bacteria exposed to sunlight, causing their toxicity to rapidly decay (295-296).
• The organization practices of Aum Shinrikyo made it difficult for scientists to work effectively. They were subject to a paranoid and distracted leadership, as demonstrated by brief abandonments of the main project to pursue the Ebola virus or a laser weapon, and worked under conditions of poor diet, sleep deprivation, and regular LSD use. These internal factors likely led to poor scientific decision-making by Mr. Endo and other, manifesting in the numerous fault of the program (296).
• The failure of Aum Shinrikyo's attempts to develop a biological weapon suggest that doing so is very difficult, contradicting statements by US officials that constructing biological weapons was easier and posed a larger threat than nuclear weapons. There appear to be significant barriers to any terrorist group developing an independent biological weapons capacity (297-298).
• Focus on biological weapons threats could still come from the acquisition of biological agents by terrorist groups by other means, namely theft from national governments -- as nearly happened in the USA in May 1995 -- or the distribution of these agents to terrorist groups by national governments (297).
• Since only Aum Shinrikyo tried to develop a biological weapon, this may suggest that cults with apocalyptic visions, especially those whose members are highly educated and have extensive financial resources, are more likely than other groups to develop biological weapons (298).
• A profile of which groups are likely to develop biological weapons could be greatly advanced from analysis of existing records on Bhagwan Shree Rajneesh, or by the release of information on Aum Shinrikyo members and activities by the Japanese government (298).