Share thisThe United States has entered into an uneasy time where the study of dangerous biological agents is on the rise. The federal government is channeling millions of dollars into research that is requiring the construction of biosafety laboratories. At the heart of biosafety is the containment of hazardous agents through multiple levels of barriers. Primary barriers pertain to equipment such as gloves, gowns, masks, biosafety cabinets, and respiratory protection as well as the use of good laboratory techniques. Secondary barriers are addressed through facility design with airtight rooms, air handling and filtration, air locks, sewage treatment, waste disposal, sterilizers, and redundant services and equipment. Tertiary barriers deal with the physical operation with items such as walls, fences, security, and animal exclusion zones. Due to the varying risk of biological agents, the facilities that handle these agents need to be designed and classified accordingly.1
Biosafety Laboratories
There are four levels of biosafety laboratories which are designated in the United States as Levels 1, 2, 3 and 4. A Biosafety Level 1 or 2 (BSL 1 or 2) facility would not necessarily have any waste treatment requirements. BSL 1 laboratories work with strains of microorganisms not known to consistently cause disease in healthy adult humans, while BSL 2 laboratories deal with moderate-risk agents that are present in the community and are associated with human disease. BSL 1 facilities would rely on containment based upon standard microbiological practices without special primary or secondary barriers other than perhaps a sink for hand washing. Agents at BSL 2 facilities can be used safely in activities on an open bench granted that the potential for producing splashes and aerosols is low. Hepatitis B virus, HIV, and salmonellae are representative of the organisms assigned to level 2 containment areas.
Biosafety Level 3 (BSL 3) facilities require placing more emphasis on primary and secondary barriers in order to protect the community and the environment as well as the laboratory personnel. Tuberculosis and St. Louis encephalitis virus are representative of the microorganisms assigned to this containment level.