The concept of “biosafety levels” (BSL) is the basis for laboratory practices designed to prevent laboratory acquired infections and illness. CDC/NIH identifies four levels of containment. The levels are designed in ascending order, by degree of protection provided to personnel, the environment and the community. Protection is accomplished through proper containment.

The Biosafety in Microbiological and Biomedical Laboratories (BMBL) outlines containment conditions related to biosafety levels (BSLs).

A biosafety level has three components:

• Practices
• Safety Equipment – Primary barriers which are intended for personnel protection
• Facilities – Secondary barriers which are intended to protect the environment