Which is a characteristic of BSL-3 containment?

• A. Controlled access and negative pressure
• B. Open bench with no containment
• C. No PPE required
• D. Only field work allowed

Answer: (A)

In BSL-3 containment, the goal is to prevent exposure to dangerous agents by controlling how people enter and how air moves in the lab. A defining feature is controlled access together with negative pressure. Controlled access means entry is restricted to trained personnel under strict procedures, with doors that are kept closed and access limited to authorized individuals. Negative pressure means the room is kept at a lower pressure than surrounding areas so air flows into the lab rather than out when a door is opened or a seal is breached; this helps contain any aerosols and prevents them from escaping to other parts of the facility. This combination, often backed by directional airflow and HEPA-filtered exhaust, is what keeps the environment and workers safe. Open bench work with no containment, no PPE, or restricting work to field settings would not provide the necessary protection for the pathogens involved, so they don’t fit BSL-3 containment.