The old arsenal in Herisau built in 1919 by Alfred Ramseyer and Fritz Hiller is a listed building. The project framework is to convert the existing stock and to add an annex parallel to the main building. The central building houses the cantonal department of security and justice. This includes offices and laboratories of the Canton police, the Cantonal emergency services switchboard, the public prosecutor's office and the office for military and civil defence with various training rooms. The state archive and its library is also to be housed in the new complex.