CAS Clean-Air-Service AG CAS Clean-Air-Service AG, which has its headquarters in CH-9630 Wattwil, is the leading vendor of services in the field of clean room measurement systems and has earned an excellent reputation for itself in terms of high-grade products and services. Founded in 1989, the company today employs 40 persons. Besides its principal market Switzerland, CAS Clean-Air-Service AG operates branch offices in Germany and Austria.