A biosafety level (BSL) is a set of biocontainment precautions (i.e. PPE, procedures, equipment, etc.) required to isolate dangerous biological agents in an enclosed laboratory facility. In the United States, the Centers for Disease Control and Prevention (CDC) have specified these levels. The levels (BSL-1,2,3 and 4) are designated in asecending order, by degree of protection provided to personnel, the environment, and the community. Standard microbiological practices are common to all laboatories. Each BSL builds on and includes the biocontainment procedures and precautions employed at lower levels of containment. Selection of the appropriate BSL is based on a thorough biosafety risk assessment of the biological agents and laboratory procedural hazards that will used in the laboratory.
BSL 1 - is suitable for work involving well-characterized agents not known to consistently cause disease in immunocompetent adult humans and present minimal potential hazard to laboratory personnel and the environment. Work is typically conducted on open bench tops using standard microbiological practices. Special containment or facility design is not required, but may be used as determined by appropriate risk assessment. Laboratory personnel receive specific training in the procedures conducted in the laboratory and are supervised by a scientist with training in microbiology or a related science.
BSL 2 - is suitable for work with agents associated with human disease and pose moderate potential hazards to personnel and the environment. BSL-2 differs from BSL-1 primarily because: 1) laboratory personnel receive specific training in handling pathogenic agents and are supervised by scientists competent in handling infectious agents and associated procedures; 2) access to the laboratory is restricted when work is being conducted; and 3) All procedures in which infectious aerosols or splashes may be created are conducted in BSCs or other physical containment.
BSL 3 - is suitable for work involving indigenous or exotic agents which may cause serious or potentially lethal disease as a result of exposure by inhalation. Laboratory personnel receive specific training in handling pathogenic and potenially lethal agents and must be supervised by scientists competent in handling infectious agents and associated procedures. All procedures involving the manipulation of infectious materials must be conducted within BSCs or other physical containment devices. A BSL-3 laboratory has special engineering and design features.
BSL 4 - is required for work with dangerous and exotic agents that pose a high risk of aerosol-transmitted laboratory infections and life-threatening disease. BSL-4 laboratories are not allowed at Stony Brook University.
For details on the criteria, practices, and facility requirements for each biosafety level go to: