Biosafety Tricky Topics - Aerosols and Biohazards

November 1, 2022 - K. Bullard

Aerosols and Biohazards

Almost all procedures in the lab can create aerosols.  Solid or liquid aerosol particles are suspended in air by breaking surface tension or imparting energy to a substance. Heavier, larger particles fall out of the air quickly and create a risk of surface contamination increasing the direct contact of mucous membranes and open skin via self-inoculation by touching these surfaces.  Smaller aerosols are higher risk as they can remain suspended in air currents which move them to new locations away from where they were originally generated.  Close to 80% of lab acquired infections have an unknown route of exposure pointing to smaller aerosols.

Procedures that Create Aerosols


Dissemination of aerosols through high-speed revolutions due to open tubes, tubes that crack, snap-cap tubes not sealed, expired tubes, overfilled tubes, and no secondary containment. 

Containment with safety buckets and safety rotors are required for biohazardous material processing.  Ensure appropriate balancing of the centrifuge. Always check the vessels prior to centrifuging:  do not overfill, ensure they are not expired, and the integrity. Waiting at least 1-5 minutes after the centrifuge stops prior to opening is highly recommended and with higher risk materials it is required.

Cell Sorting

Cell sorters use high pressure to separate cells into a single stream and further separate specially labelled cells.  In the event the instrument becomes clogged, or a deflection occurs, this can cause a significant aerosol cloud to erupt from the instrument.

Companies are working to help confine aerosols within the sorter when in use, however some may require containment in a biosafety cabinet. 

Documentation of procedures for sorting BSL-2 materials is required to use the flow cytometry core at MSU.


Dropped flasks of biohazard material create aerosols of different sizes and require evacuation of the laboratory if it occurs outside of the biosafety cabinet. After aerosols are given appropriate time to settle, EHS trained personnel can assess the situation and perform the clean up procedure. Contact EHS to inform them of the spill and clean up procedure. If the spill is too large for the kit, contact EHS immediately for assistance.

Vortexing, Blending, Homogenizing

Energy directed at the material through these means, presents a significant increase in aerosol creation risk.  It is recommended that all three of these procedures be done within a biosafety cabinet when biohazardous materials are used. Contact EHS Biosafety Team for information on specialty cabinets or other information.