Errors to avoid in laboratory use of biosafety cabinets

Biological safety cabinets are designed as primary containment environments that provide protective barriers. Incorrect use of biohazard cabinets can compromise the safety of laboratory personnel and contaminate the cultures under investigation. Strict procedures are imperative.

Research and assembly work on micro-organisms requires sterile and contained conditions. Bio safety cabinets contain hazardous aerosols by means of air and physical barriers and air filtration through a high efficiency particulate air (HEPA) filter. A directional airflow from the laboratory past the researcher and over the work bench captures hazardous aerosols that are generated during experiments and carry them to the HEPA filters where they are trapped.

A biohazard safety cabinet has grills at the top, front and rear to allow for air intake and outflow. This air is HEPA filtered both as it enters the cabinet to remove extraneous particulates and on outflow, to remove hazardous aerosols that may have been generated during investigations. Researchers should avoid placing any materials on top of the cabinet and near the sides where the air intake our outflow may be disrupted.

It is also important to keep all laboratory accessories out of the cabinet airflow space. This includes papers, tissues and wipers, vials and other small and light glass equipment that could be moved by air currents close to the grilles. If these items impact on the air flow grills they could also damage the internal components of the cabinet. Any attempt to place items on top of the cabinet could damage the HEPA filter. It is equally important never to leave food anywhere near the airflow to and from the cabinet. Contaminants could affect the food and the laboratory personnel may ingest toxins.

Alarms and movements
Cabinet alarm systems should never be disengaged, even if the researcher feels confident about
well-practiced procedures. The alarm indicates when air flow changes into a form that could endanger the integrity of the experiment.

Sudden movements near the cabinet or during experimental procedures may also disrupt the air flow and make it turbulent. Such movements include opening windows, slamming doors or moving suddenly from a desk close to the cabinet when it is in use by someone else. This will compromise both the experiment and the personal safety of the researcher.

Testing and front sash
The motor powering the airflow should be tested for at least five minutes prior to any investigations taking place in the cabinet. But the front sash of the cabinet should not be closed during this time, or any other time when the motor is running. If the sash is closed it could force the motor to burn out.


A biohazard safety cabinet is vital equipment for the investigation of micro-organisms and hazardous materials. They depend on a laminar and uninterrupted flow of air over the work area to ensure that both the researcher and the specimens under investigation remain uncontaminated. All researchers have to be aware of correct operating procedures that do not disrupt the air flow or introduce hazardous aerosols into the cabinet or the laboratory.

Susan Jenkins is an industrial chemist with 30 years experience. She has pioneered research into skincare products and writes for a wide range of cosmetics industry websites and blogs. Click here to learn more about biosafety cabinets.

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