Below are the definitions of Biosafety Levels 1-4, as described in the Biosafety in Microbiological and Biomedical Laboratories (BMBL), 5th Edition.
Biosafety Level 1: work involving well-characterized agents not known to consistently cause disease in immunocompetent adult humans, and presents minimal potential hazard to laboratory
personnel and the environment.
- Work is typically conducted on open bench tops using standard microbiological practices. Special containment equipment or facility design is not required, but may be used
as determined by appropriate risk assessment. Laboratory personnel must have specific training in the procedures conducted in the laboratory and must be supervised by a scientist with
training in microbiology or a related science.
Biosafety Level 2: suitable for work involving agents that pose moderate hazards to personnel and the environment.
- It builds upon BSL-1. It differs from BSL-1 in that 1) laboratory personnel have 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 equipment.
Biosafety Level 3: clinical, diagnostic, teaching, research, or production facilities where work is performed with indigenous or exotic agents that may cause serious or potentially
lethal disease through inhalation route exposure.
- Laboratory personnel must receive specific training in handling pathogenic and potentially 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, other physical containment devices, or by personnel wearing
appropriate personal protective equipment.
Biosafety Level 4: work with dangerous and exotic agents that pose a high individual risk of life-threatening disease, aerosol transmission, or related agent with unknown risk of
- Agents with a close or identical antigenic relationship to agents requiring BSL-4 containment must be handled at this level until sufficient data are obtained either to confirm
continued work at this level, or re-designate the level. Laboratory staff must have specific and thorough training in handling extremely hazardous infectious agents. Laboratory staff must
understand the primary and secondary containment functions of standard and special practices, containment equipment, and laboratory design characteristics. All laboratory staff and
supervisors must be competent in handling agents and procedures requiring BSL-4 containment. Access to the laboratory is controlled by the laboratory supervisor in accordance with
Questions regarding Biosafety Levels may be addressed to Krista Murray or call 831-1433.