The Tokyo gas attack of 1995 was one of the most serious terrorist events in Japanese history. In a nation which is relatively free of crime, members of the Aum Shinrikyo cult released sarin, a nerve agent, into crowded subways during rush hour, killing 12 people and injuring hundreds more. The Tokyo gas attack had a profound impact on Japanese society, and it drew international attention to Japan and its culture.
On 20 March 1995, five members of the Aum Shinrikyo cult entered the Chiyoda, Marunouchi, and Hibiya subway lines in Tokyo. Drivers waited outside at prearranged stations to pick the men up. The men carried bags of sarin wrapped in newspaper, along with umbrellas to pierce the bags with. They boarded trains which were extremely crowded during the peak of Monday morning rush hour, and pierced the bags repeatedly to expose the liquid sarin to the air. It rapidly vaporized into a gas format, poisoning the passengers on the train.
The subway authority did not take the trains immediately out of service, although numerous passengers started to feel ill. Witnesses of the Tokyo gas attack said that several subway stations resembled battlefields, with gas victims lying in the streets and on the sidewalks. Several subway employees exposed themselves to the gas when they entered the cars to clean up the wet newspapers left behind. Once the subway authority realized what was happening, the affected trains were removed from service.
Emergency services were quickly overwhelmed by the victims of the Tokyo gas attack, many of whom were transported by car when ambulances became unavailable. Many hospitals did not realize that they were receiving victims of sarin poisoning, and even after knowledge that the culprit was gas became widespread, hospitals were unsure about how to treat it. Most victims experienced vision problems and headaches, with others suffering more extensive nervous system damage. Hundreds of people suffered long lasting nervous system and psychological problems.
Aum Shinrikyo had been linked with previous chemical attacks, including a previous sarin attack. Several members of the cult were arrested, tried, and sentenced to death or life in prison. While the group was not outlawed in Japan, the cult's protected religious status was removed, and investigations revealed that Aum had been involved in extensive biological and chemical weapons research, leading to concerns around the world.
Within Japanese society, the Tokyo gas attack was an extremely serious event. Over five years after the Tokyo gas attack, many surveyed victims demonstrated symptoms of post traumatic stress disorder. Japanese society in general was severely shaken by the Tokyo gas attack, which was an unprecedented crime in Japanese history. The legal system, police, and emergency services were all heavily criticized in the wake of the Tokyo gas attack, as many Japanese citizens felt that the actions taken during and after the attack were not sufficient.