Working with biological material can sometimes pose a danger to laboratory staff and the environment. For this reason, staff must correctly handle material according established standards. These standards comprise four biosafety levels (BSLs) that typically apply to biological materials. Depending on the level, laboratory staff will have to possess a certain set of skills for handling potentially dangerous material. Aerosols forming during standard lab procedures like pipetting, mixing, and centrifuging poses the greatest potential risk for infection. To minimize the risk of infection from bioaerosols, primary and secondary barriers are used. A primary barrier could, for instance, be a biosafety cabinet (BSC). A secondary barrier might be an autoclave (BSL-2) or, in a higher-level situation, an installation inside a facility like a dedicated anteroom or ventilation system might serve as the barrier. Infectious material might include bacteria, viruses, cell cultures, parasites, or particular types of fungi. Depending on the security standard in place, special training may be required to handle these infectious materials. The laboratory supervisor is responsible for correctly educating laboratory staff.