Which biosafety cabinet class is designed to protect the user against direct contact with the cabinet contents?

• A. Class I
• B. Class II
• C. Class III
• D. All of the above

Answer: (C)

Class III biosafety cabinets are designed for the highest level of containment and protect the user by being completely enclosed and gas-tight. The operator works through gloves that are permanently attached to the cabinet, so there is no direct contact with the cabinet contents. Materials and air travel through integrated filtration, keeping both the user and the environment protected from exposure. In contrast, the other cabinets involve openings or accessible work areas, where direct contact with contents could occur if proper barriers aren’t used. So, for preventing any direct contact with the contents, the completely enclosed, glove-equipped Class III is the design used.