What ABSL level is used for working an infectious agent that is well characterized and known to not cause disease in humans?

• A. ABSL 1
• B. ABSL 2
• C. ABSL 3
• D. ABSL 4

Answer: (A)

ABSL level one is used when the infectious agent is well characterized and not expected to cause disease in healthy humans. Because the risk is minimal, only basic containment is required: standard biosafety practices, basic personal protective equipment (like a lab coat and gloves as needed), and routine surface decontamination. No special containment equipment or engineering controls are needed, and work can be done on open benchtops with conventional housing and handling practices. This level is appropriate for nonpathogenic organisms commonly used in teaching and research (for example, well-characterized strains like E. coli K-12). If there were any potential to cause disease or uncertainty about risk, a higher ABSL would be chosen to provide greater protection.