What is biosafety level 3 laboratory?

Biosafety Level 3 (BSL-3) laboratories are designed for work involving microorganisms that can cause serious and potentially lethal disease through inhalation (aerosol transmission).

Agents handled at BSL-3:

Pathogens with potential to cause severe human or animal disease.

Transmitted primarily through respiratory routes.

Treatments or vaccines may be available but are not always effective.

Examples include Mycobacterium tuberculosis, Brucella spp., Francisella tularensis, Coxiella burnetii, SARS-CoV-2, and West Nile virus.

Importance of BSL-3:

Crucial for studying airborne pathogens that pose public health risks.

Supports development of vaccines, diagnostics, and treatments.

Enables safe surveillance and handling of pathogens during outbreaks.

Key containment and engineering features:

Laboratory is physically separated from unrestricted traffic flow areas.

Controlled, directional airflow (negative pressure) ensures that air flows into the lab but not out.

Exhaust air is not recirculated and is filtered using HEPA filters.

Walls, floors, and ceilings are sealed for easy decontamination and to contain spills or aerosols.

Safety and procedural protocols:

Restricted access to trained, authorized personnel.

Mandatory use of personal protective equipment (PPE): solid-front gowns or coveralls, gloves, face protection (goggles, face shields), and respiratory protection (e.g., N95 masks, powered air-purifying respirators).

All procedures involving infectious materials must be conducted in a Class II or Class III biosafety cabinet.

Comprehensive decontamination protocols for waste, surfaces, and equipment.

Emergency protocols for spills, exposures, and ventilation failures must be in place.

Applications of BSL-3 laboratories:

Clinical diagnosis of airborne pathogens.

Research in microbial pathogenesis, immunology, and infectious diseases.

Public health surveillance and epidemiological investigations.

Vaccine development for airborne infectious agents.

Design considerations:

Laboratories must have an anteroom or airlock for donning PPE and maintaining pressure differentials.

Surfaces must be seamless and water-resistant to prevent contamination and allow thorough cleaning.

Autoclaves or other validated decontamination systems must be available onsite.