Defined biosafety levels provide guidelines to ensure an appropriate amount of protection for laboratory users and the environment based on biological risk. Biosafety level correlates with, but is not the same as, risk group. Increasing requirements for both physical containment and procedural details come with increasing levels of protection. For more detailed information, consult the most current edition of “Biosafety in Microbiological and Biomedical Laboratories.” See Appendix D for biosafety levels appropriate for work with specific agents. Each level includes the requirements of all lower levels.
Biosafety Level 1 (BSL-1)
BSL-1 facilities and practices are 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 the open bench tops using standard microbiological practices. Special containment equipment or facility design is not required. 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.
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.BSL-1.
Biosafety Level 2 (BSL-2)
BSL-2 builds upon BSL-1. BSL-2 is suitable for work involving agents that pose moderate hazards to personnel and the environment. It differs from BSL-1 in that
- Primary hazards to personnel working with these agents relate to accidental percutaneous or mucous membrane exposures or ingestion of infectious materials. Extreme precaution with contaminated sharps must be emphasized. BSL-2 facilities and practices are suitable for work involving agents that pose moderate hazards to personnel and the environment.
- Laboratory personnel have specific training in handling pathogenic agents and are supervised by scientists competent in handling infectious agents and associated procedures.
- Access to the laboratory is restricted when work is being conducted.
- All procedures in which infectious aerosols or splashes may be created are conducted in BSCs or other primary containment equipment. Other primary barriers must be used as appropriate, such as splash shields, face protection, gowns, and gloves. Secondary barriers such as hand washing and waste decontamination facilities must be available to reduce potential environmental contamination.
Biosafety Level 3 (BSL-3)
Applicable to 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.
- Infectious agents present an inhalation risk.
- 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.
- A BSL-3 laboratory has special engineering and design features to ensure containment of airborne disease agents.
Biosafety Level 4 (BSL-4)
Currently Kansas State University has no BSL-4 facilities nor is it permitted to have any BSL-4 facilities.
BSL-4 is required for 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 transmission. 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 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 institutional policies.
There are two models for BSL-4 laboratories: A Cabinet Laboratory where all handling is done of agents must be performed in a Class III BSC, and a Suit Laboratory where personnel must wear a positive pressure protective suit. BSL- 4 Cabinet and Suit Laboratories have special engineering and design features to prevent microorganisms from being disseminated into the environment.