Biological safety cabinets reduce hazards by three methods: isolation of the biohazard to an identifiable area, containment of the biohazard, and removal of the biohazard from the exhaust air stream.
Class I biological safety cabinets utilize airflow to protect the user and environment from hazards in the cabinets... [C]lass II biological safety cabinets use tightly balanced airflow to protect the user and environment from hazards present in the cabinet and to prevent contamination of the product inside the cabinet... [C]lass III BSCs [a.k.a. glove boxes] protect the user, environment, and product by means of a physical barrier, i.e., an enclosed box where the product inside is manipulated with attached "rubber" gloves. Class II biological safety cabinets are most frequently utilized in biomedical laboratories. [Crane, 1994]
