The production of FMD vaccines requires special high-containment facilities both to protect the product from other microorganisms and the outside environment from escape of virus. In addition to producing the cells and virus in closed, sterile stainless steel tanks and connecting pipework, the atmosphere of the production suite is maintained at a negative pressure to ambient and both the inlet and extract air ducting is fitted with absolute (HEPA) filters. A complex air handling system is employed which ensures an increasing negative pressure gradient and, thus, airflow towards the virus manipulation areas. Such facilities are also protected by change and shower areas at the entrance.