Atmospheric Continuum Mechanics Research Facility

The Atmospheric Continuum Mechanics Research Facility (大気連続体力学研究所) is a facility located in School District 4.

Principles
As its name suggests, the primary subject of research at the facility is atmospheric continuum mechanics. The research facility is connected to a company which compresses and sells air.

Behind the scenes, the facility was also involved in the development of a secret weapon, which was intended to be used against Accelerator, and likely supported by a member of the Academy City Board of Directors. The Anti-Accelerator weapon (対一方通行用兵器) in question is in fact an Ultra-high Pressure Water Cutter (超高圧ウォーターカッター) which uses the melting of solid nitrogen (frozen solid at under -210°C). The weapon has two outlets worn on the arms which can fire the high-pressure nitrogen in a stream or explosive pellets which can be detonated remotely, a magazine of nitrogen blocks worn on the back, and a protector which can freeze and neutralize bullets. While the cutting stream and explosive pellets are destructive, the hidden aspect of the weapon is the unseen scattering of the nitrogen resulting from its usage, which causes oxygen deprivation for those close-by. It should noted however that while methods of oxygen deprivation can bypass Accelerator's Redirection, as shown by Misaka 10032 with ozone, once it becomes known it can be easily dealt with.

Toaru Kagaku no Accelerator
Early in the morning, on the day when Accelerator's bandages from his headshot wound were due to come off, a trio of high school students; Takada Youko, Nakahara Hiromi and Kidera Minori, broke into the facility and stole the secret weapon that was being developed, intending to use it against Accelerator and steal a sample of his genetic information to sell. Anti-Skill were called to the scene but the trio made their getaway by cutting through the floor and escaping through the underground.

After the break-in, Anti-Skill learned of the secret weapon's development however the facility declined to provide specifics, likely aided by the Board's influence. Yomikawa Aiho and her colleagues were able to learn that it was intended to be used against Accelerator by looking at similar research in the database. As the VIPs were monopolizing Anti-Skill's resources after the theft of a secret weapon, claiming that they were likely targets, the personnel dispatched to stop the thieves were limited. When the thieves attacked Heaven Canceller's Hospital, they were defeated by Accelerator and subsequently apprehended, with the weapon itself being destroyed.