Module 1: Laboratory safety

Module 1.2: Biosafety and Biohazardous Waste


The CDC defines biosafety as “the application of safety precautions that reduce a laboratorian’s risk of exposure to a potentially infectious microbe and limit contamination of the work environment and, ultimately, the community.” The laboratory that you will be using for your experiments and procedures is a Biosafety level 2 (BSL-2) laboratory.

What does being a BSL-2 laboratory means to you and your safety?

The Centers for Disease Control and Prevention (CDC) and the National Institute of Health have established four levels of containment called Biosafety levels (BSLs). Each level has specific control measures for the containment of types of microbes and biological agents. The levels are assigned based on the evaluation of specific risks that the microbe or biological material may have on laboratory personnel and the community. The level of containment correlates with infectivity, the severity of disease, transmissibility, and the nature of the work conducted. Other risk factors that may also play in the determination of the BSL level include the origin of the microbe or agent and route of exposure.

BSL Levels. BSL-1 (low risk) through BSL-4 (high risk)
Biosafety Levels (BSLs)

The CDC defines containment requirements for BSL-2 as the following:


“If you work in a lab that is designated a BSL-2, the microbes there pose moderate hazards to laboratorians and the environment. The microbes are typically indigenous and associated with diseases of varying severity. An example of a microbe that is typically worked with at a BSL-2 laboratory is Staphylococcus aureus.”

The containment requirements that we are required to abide by including the following.

Laboratory practices

  • Access to the laboratory is restricted when work is being conducted.
In our lab, this means that we do not allow individuals that are not enrolled or part of the teaching staff into the laboratory when we are conducting procedures.

Safety equipment

  • Appropriate personal protective equipment (PPE) is worn, including lab coats and gloves.
  • Eye protection and face shields:
    • Eye protection must be worn when staff or students are handling risk group 2 (RG2) organisms at the benchtops
    • Face shields must be used when performing procedures that may create a splash hazard
  • All procedures that can cause infection from aerosols or splashes are performed within a biological safety cabinet (BSC).
  • An autoclave or an alternative method of decontamination is available for proper disposal.
In our lab, unless specified otherwise, you are required to wear clean scrubs (top and bottoms) or a long laboratory coat with long pants or a skirt along with closed-toed shoes with disposable gloves. You are responsible for the proper disposal of biological hazards into the appropriate waste containers (discussed later). You are required to disinfect your tables and equipment before leaving the laboratory. The laboratory staff will dispose of the biological waste for decontamination.

Facility construction

  • The laboratory has self-closing doors.
  • A sink and eyewash are readily available.

Every laboratory, including ours, regardless of the biosafety level follows the standard of microbiological practices. These practices include but are not limited to:

  • Not eating, drinking, or applying cosmetics in the lab
  • Washing hands after working with infectious materials and before leaving the lab
  • Routinely decontaminating work surfaces
If you leave the laboratory session without disinfecting your benchtops, disposing of your laboratory materials, or turning off and unplugging your microscope, your entire group will lose 2 points that day.

Biohazardous waste

In this laboratory, we will be working with BSL-2 agents as part of your learning experience. To ensure everyone’s safety and enjoyable learning environment, we have a rigorous biohazard waste policy.

What is biohazardous waste?

Biohazardous waste, also called infectious waste or biomedical waste, is any waste containing infectious materials or potentially infectious substances such as blood. Of special concern are sharp wastes such as needles, blades, glass pipettes, and other wastes that can cause injury during handling. The waste reciprocals are labeled with the following red biohazard waste label.


Biohazard waste label
Biohazard Waste Label

1. Sharps container

Each of your benches is equipped with a sharps container. Items that are sharp enough to puncture the skin and contaminated with unsterilized biological material should be placed in these bins.

Examples of items used in our lab that should be placed into the sharps container include:

  • sharps containers
    Sharps Containers

    Glass Pasteur pipettes

  • Glass slides
  • Biologically contaminated broken glass

If they are overflowing or reaching capacity (3/4 full) please notify an instructor or teaching assistant.


2. Solid non-sharp biohazardous waste

Large biohazardous trash cans are located throughout the lab and are denoted by the large orange biohazardous waste sticker on their sides or lids. Lab consumables that have come in contact with viable biological material that contains any laboratory material that is regarded as potentially infectious should be placed in the bins.

Examples of these types of items that should be placed in the biohazardous bins include:

biohazardous bins
Biohazardous Bins
  • Gloves
  • Culture flasks
  • Plastic pipettes
  • Pipette tips and well plates
  • Wastes items contaminated with blood or other infectious or biological material


3. Liquid biohazardous waste

In some labs, we will be working with biohazardous liquids, mainly for fecal and urine procedures. On those days, the liquids should be placed in the liquid biohazard waste containers.

Knowledge check

Key Takeaways

  • Experiments and procedures are done inside the silver tray on your bench
  • The black countertop is your non-procedure/experiment workspace
  • We wear approved laboratory attire when in the microbiology laboratory space
  • You will be working with BSL-2 pathogens
  • If you do not know how to dispose of waste product, please ask.


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Clinical Veterinary Diagnostic Laboratory Copyright © 2021 by Erin Burton is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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