In AP containment level 3, all open vessel activities with zoonotic materials are conducted in a biological safety cabinet. In AP containment level 4, all activities with microorganisms are conducted in a BSC in order to minimize contamination of the lab. Every employee working in a BSC must be trained in its correct use and have a good understanding of the different types of cabinets and how they work. Class I cabinets have unrecirculated air flow away from the operator that is discharged through a HEPA filter. Class III cabinets are totally enclosed and gas-tight with HEPA filtered supply and exhaust air.
Work is performed with attached long-sleeved gloves.
Class III cabinets protect the worker and the product. Selection of the proper class of BSC requires careful evaluation of the work involved. Cabinet air from Type A cabinets may be recirculated back into the laboratory in level 2 and 3 facilities. The exhaust canopy must allow for proper BSC certification. Type B2 cabinets are total-exhaust cabinets with no air recirculation within them and are suitable for work with small amounts of volatile chemicals and radionuclides.