Assistant Laboratory Animal Technician (ALAT) 2025 – 400 Free Practice Questions to Pass the Exam

A Class III biological safety cabinet (BSC) offers the highest level of user protection from pathogens. This type of cabinet is designed for handling highly infectious agents and operates under negative pressure, ensuring that no air escapes into the laboratory environment. It features a completely sealed exterior with a high-efficiency particulate air (HEPA) filter that provides absolute containment.

In a Class III BSC, users operate equipment through glove ports, ensuring a barrier between them and the materials being handled, which prevents any potential exposure to pathogens. This design is particularly important for work involving biosafety level 4 (BSL-4) pathogens, where the risk of exposure is significant, and protection against even the smallest aerosol particles is critical.

While Class I and Class II BSCs provide substantial protection, they do not achieve the same level of containment and user safety as the Class III model. Class II BSCs, for instance, are more common and allow for some direct airflow into the cabinet, which can pose a risk of exposure with certain pathogens if not properly maintained. Class IV BSCs are not typically classified in the same way as the Class I, II, and III categories; they are usually part of a containment facility rather than standalone cabinets and are