A biosafety level (BSL) is a set of biocontainment precautions 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.
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.
BSL 2 - is suitable for work involving agents that pose moderate potential hazards to personnel and the environment. 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 must 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.
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: