The University of Arizona

Biosafety Containment Levels

Research Laboratory & Safety Services

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Campus Mail:
PO Box 245101

Phone: (520) 626-6850
Fax: 520-626-2583

Mailing Address:
Research Laboratory & Safety Services
PO Box 245101
Tucson, AZ 85724

Street Address:
1717 E. Speedway Blvd, Suite 1201
Tucson, AZ 85719

Biosafety Levels and Postings

Biosafety Level 1

Suitable for work involving well-characterized agents not known to cause disease in healthy humans and are of minimal potential hazard to laboratory personnel and the environment.

Examples include:

  • Bacillus subtilis
  • Bacillus cerculans
  • Escherichia coli (non-pathogenic strains of E. coli such as K-12)
  • Murine cell lines
  • Samples from lab mammals

When working at BSL-1, workers must follow all standard microbiological practices, receive all specific training on procedures and equipment and wear the minimum personal protective equipment (PPE) of a lab coat and gloves.

Laboratories must be locked when unoccupied. All agents must be secured against accidental exposure, unauthorized use, and theft. All recombinant nucleic acids must be stored in locked containers.

Biosafety Level 2 (BSL-2)

BSL-2 is suitable for work involving agents that pose moderate hazards to personnel and the environment. It differs from BSL-1 in that:

  • Laboratory personnel have specific training in handling pathogenic agents and are supervised by scientists competent in handling infectious agents and associated procedures;
  • Access to the laboratory is restricted when work is being conducted; and
  • All procedures in which infectious aerosols or splashes may be created are conducted in BSCs or other physical containment equipment.

At BSL-2, workers are required to follow the standard microbiological practices and wear the minimum personal protective equipment (PPE) of a lab coat and gloves. Additional PPE may be required. The Approval Holder must ensure that laboratory personnel demonstrate proficiency in standard and special microbiological practices before working with BSL-2 agents.

Additional requirements at BSL-2 are:

  • Access to the lab is limited when work is being conducted and must be locked when unoccupied.
  • All aerosol-generating procedures must be performed in the biosafety cabinet or otherwise appropriately contained.
  • Infectious materials must be placed in a durable, leak proof container during collection, handling, processing, storage, or transport within a facility.
  • Laboratory equipment should be routinely decontaminated, as well as, after spills, splashes, or other potential contamination.
  • Spills involving infectious materials must be contained, decontaminated, and cleaned up by staff properly trained and equipped to work with infectious material.
  • Medical surveillance and vaccines may be required for specific work.
  • Incidents that may result in exposure to infectious materials must be immediately evaluated and treated according to procedures described in the laboratory biosafety manual. All such incidents must be reported to the laboratory supervisor. Medical evaluation, surveillance, and treatment should be provided and appropriate records maintained.
  • Standard Operating Procedures (SOPs) are required to be available to all laboratory workers and any visitor or contractor upon request. A template for the SOPs is available here. The SOPs must contain:
    • Agent specific information.
    • Lab specific bio-containment procedures.
    • Decontamination and waste procedures.
    • Applicable Medical Surveillance Program information.
    • Acknowledgement pages signed by laboratory workers and visitors.

Examples of agents worked with at BSL-2 include: Human samples and cell lines, Aspergillus fumigatus, Toxoplasma gondii, Salmonella typhimurium and Influenza A.

All agents must be secured against accidental exposure, unauthorized use, and theft. All recombinant nucleic acids and BSL-2 agents must be stored in locked containers. All material in the open bay or common use areas must be secured when not in use.

NOTE: All work involving the use of cultured human and non-human primate cell lines, according to the University of Arizona’s Biosafety Manual, must be conducted at Biosafety Level 2.

Biosafety Level 3 (BSL-3)

Biosafety Level 3 work involves agents that may cause serious and potentially lethal infection. The primary routes of exposure to personnel working with these agents are: inhalation, auto inoculation, and ingestion.  BSL-3 is the highest containment level laboratory at the University of Arizona.

Workers must have experience working in BSL-2 and be very familiar with all standard and all special microbiological practices prior to working at BSL-3. 

Examples of agents worked with at BSL-3 include: Coccidioides immitis and posadasii, Mycobacterium tuberculosis, Chikungunya Virus and West Nile Virus.

BSL-3 requires a specialized facility with an anteroom. The anteroom must be posted with the current agents in use. The anteroom is where PPE is donned and supplies are stored. Each anteroom is required to have a posting that lists the required PPE and the proper way to put it on and remove it.

Additional PPE requirements at BSL-3 are:

  • Water-resistant closed-front lab coat
  • Double gloves
  • Respiratory protection as required

Certain agents and any work with live animals may require additional PPE. BSL-3 workers must be fit tested for an appropriate respirator and individuals wearing contact lenses must wear eye protection.

Other additional requirements for working in the BSL-3:

  • Hand washing sinks are required to be hands free.
  • Pass through autoclaves are available in most BSL-3 laboratories at the University of Arizona. If the autoclave is outside of the laboratory, the outer bag must be decontaminated prior to leaving the laboratory. The waste must be carried in a leak proof container to the nearest autoclave and be immediately loaded into autoclave.
  • All work at BSL-3 must be performed in a biosafety cabinet. Work on the bench top with recombinant and biohazardous materials is not permitted.
  • Physical containment devices, such as centrifuge safety cups, sealed centrifuge rotors, and HEPA-filtered isolation caging for animals, are used for all activities with biohazardous materials that pose a threat of aerosol exposure.
  • Vacuum lines must have a HEPA filter.
  • The BSL-3 labs must be under negative pressure at all times. Workers must ensure the laboratory is under negative pressure prior to each time they enter the laboratory.
  • There is no recirculation of air to other areas of the building and all exhaust is HEPA filtered.
  • Windows must be completely sealed and cannot be opened.

The Approval Holder must monitor and authorize access of all individuals entering the BSL-3 laboratory. Access is limited to those who understand the nature of the biohazard, have adequate laboratory -specific biosafety training and agree to comply with all precautions. Visitors and maintenance personnel who enter the BSL-3 laboratory must be fully informed of the potential risks, required practices and procedures that they must follow. They must be instructed about the signs and symptoms of any and all biohazardous materials manipulated or stored in the laboratory and sign a statement that they understand the risks.

Laboratories must be locked when unoccupied. All agents must be secured against accidental exposure, unauthorized use, and theft. All recombinant nucleic acids and BSL-3 agents must be stored in locked containers.