Perspective: Biosafety labsBiosafety Levels in Laboratories – What is the Difference?
The United States is home to several types of laboratories that conduct medical research on a variety of infectious biological agents to promote the development of new diagnostic tests, medical countermeasures, and treatments. The CDC has devised a system of Biosafety Labs (BSL) designations. Ranked from lowest to the highest level of containment, they are BSL-1, BSL-2, BSL-3, and BSL-4. The BSL designations outline specific safety and facility requirements to achieve the appropriate biosafety and biocontainment. The BSL is assigned based on the type of infectious agent on which the research is being conducted. For example, a BSL-4 conducts research on dangerous and exotic agents with a high-risk of causing life-threatening disease, the possibility of aerosol transmission, and no known treatment or therapy (e.g., Marbug virus, Congo-Crimean virus, Ebola virus).
In July 2019, the United States Army Medical Research Institute of Infectious Disease (USAMRIID) ceased research operations after failing to meet biosafety requirements. USAMRIID is the lead research institute and only biosafety level (BSL) 4 laboratory for the Department of Defense that conducts medical biological research on high-risk pathogens.
Frankie Catalfumo writes in Global Biodefense that to better understand the implications of USAMRIID having their operations discontinued, it is critical to identify what a BSL is and how each level is designated.
The United States is home to several types of laboratories that conduct medical research on a variety of infectious biological agents to promote the development of new diagnostic tests, medical countermeasures, and treatments. “To promote safe medical research practices in laboratories studying infectious agents, the Centers for Disease Control and Prevention (CDC) and the National Institutes of Health have established four BSLs,” Catalfumo writes. “The levels consist of requirements that have identified as protective measures needed in the laboratory setting to ensure the proper management of infectious agents to avoid accidental exposure or release into the environment.”
The BSL designations, ranked from lowest to the highest level of containment, are BSL-1, BSL-2, BSL-3, and BSL-4. The BSL designations outline specific safety and facility requirements to achieve the appropriate biosafety and biocontainment. The BSL is assigned based on the type of infectious agent on which the research is being conducted. The CDC has designed an infographic to help visualize the differences between each level. Each level builds on the previous level, adding additional requirements.
Catalfumo writes this about BSL-4:
Biosfaety Level 4 (BSL-4) Conducts research on dangerous and exotic agents with a high-risk of causing life-threatening disease, the possibility of aerosol transmission, and no known treatment or therapy (e.g., Marbug virus, Congo-Crimean virus, Ebola virus). Entry into the BSL-4 laboratory is secure and limited, monitoring all persons in the facility with a logbook. Laboratory personnel are required to complete a clothing change prior to entry and shower on exit. This laboratory is customarily in a separate building or isolated area with complex engineering safety features, such as filtered ventilation systems and strict waste management requirements to prevent the release of an agent. The construction of the build forms a sealed internal shell for maximum containment. This level is found in select research laboratories.
