Legionella Testing / Biosafety Training

An Overview of Biosafety Levels

An Overview of Biosafety Levels

One of the many things you’ll learn through our Control of Biohazards biosafety training courses is the difference between the various biosafety levels. Each facility biosafety level has is a list of biocontainment precautions that are required in order to appropriately handle biological agents within a facility.  These levels range from 1 (BSL-1) to 4 (BSL-4) as specified by the CDC/NIH in the U.S. Risk analysis of the procedures and techniques to be used with each pathogen (classified by risk group (RG) ranging from 1 to 4). Risk analysis determines which facility biosafety level will be used for each research project.

·         Biosafety Level 1: BSL-1 is the lowest of the levels and the least restrictive. It requires basic biosafety training. Any biological agent that does not cause disease in a healthy human and generally poses no major threat to lab personnel and/or the environment is usually handled in a BSL-1 facility. When working under BSL-1 conditions, all standard microbiological procedures must be followed. Work can be performed on an open lab bench of table. Personal protective equipment is required (lab coat, gloves, eye protection, etc.) as needed and the facility must contain a handwashing sink and a working space separate from the rest of the facility.

·         Biosafety Level 2: BSL-2 laboratories are used for work involving agents of moderate potential hazard to humans or the environment, including microbes that may cause diseases, such as blood containing Hepatitis A, B, and C and HIV. The same precautions for BSL-1 are followed along with additional precautions such as negative directional airflow into the lab and biosafety cabinets (BSCs). Lab personnel working in BSL-2 laboratories must have specific biosafety training to handle these agents. Access into the lab is restricted when work is in progress. Contaminated sharp objects must be handled with caution. Most procedures are performed in biosafety cabinets for primary containment of aerosols.

·         Biosafety Level 3: When working in a BSL-3 lab, the microbes involved are either indigenous or exotic and can cause serious, potentially lethal disease through the inhalation route. Mycobacterium tuberculosis, the bacterium that causes tuberculosis, is one example. All lab personnel receive specific biosafety training for the microorganisms to be investigated. Vaccination and medical surveillance may be required. BSL-3 labs are restricted to just people that work in the lab, have a double-door entry, all work is performed in biosafety cabinets. The laboratory has HEPA-filtered room exhaust and is designed to be gas-tight to permit gaseous decontamination.

·         Biosafety Level 4: BSL-4 is the highest level of biosafety laboratory. People work with microorganisms that are dangerous, exotic, and pose a high risk of fatal infections with no current treatment or vaccines. Examples include the Ebola and Marburg viruses. BSL-4 laboratories require workers to change clothing before entering, shower upon exiting, and decontamination of all materials before exiting the lab. All personnel must receive task-related biosafety training and all work must be performed while wearing a full body, HEPA-filter air-supplied suit and/or an appropriate Class III biosafety cabinet line. The lab itself is in a completely separate, isolated building from the rest of the facilities.