Biological Safety in Laboratories

Biological safety guidelines for laboratory work are provided in the text, Biosafety in Microbiological and Biomedical Laboratories prepared by the Centers for Disease Control and the National Institutes of Health. The guidelines may be obtained by contacting the Environmental Health and Safety office or contacting the U.S. Government Printing office (HHS Publication 88-8395).

Biosafety Level 2 Containment Practices, Facilities, And Equipment

Biosafety Level 2 (BL2) is suitable for laboratory work involving biological agents of moderate potential hazard to personnel and the environment. Access to the laboratory shall be limited when work is being conducted and certain procedures in which infectious aerosols are created are conducted in biological safety cabinets or other physical containment equipment.

Standard Microbiological Practices - BL2
  1. Access to the laboratory shall be limited or restricted by the principal investigator when work with infectious agents is in progress.
  2. Work surfaces shall be decontaminated once a day and after any spill of viable material.
  3. All contaminated liquid or solid wastes shall be decontaminated before disposal.
  4. Mechanical pipetting devices shall be used; mouth pipetting is prohibited.
  5. Eating, drinking, smoking, and applying cosmetics shall not be permitted in the work area. Food may be stored in cabinets or refrigerators designated and used for this purpose only. Food cabinets or refrigerators shall be located outside the work area.
  6. Persons shall wash their hands after they handle viable materials and animals and before leaving the laboratory.
  7. All procedures shall be performed carefully to minimize the creation of aerosols.
Special Practices - BL2
  1. Contaminated materials that are to be decontaminated at a site away from the laboratory shall be placed in a durable, leakproof, closed container before being removed from the laboratory.
  2. The principal investigator shall limit access to the laboratory. In general, persons who are at increased risk of acquiring infection or for whom infection may be unusually hazardous shall not be allowed in the laboratory or animal rooms. The principal investigator has the final responsibility for assessing each circumstance and determining who may enter or work in the laboratory.
  3. The principal investigator shall establish policies and procedures whereby only persons who have been advised of the potential hazard and meet any specific entry requirements, such as immunization, enter the laboratory or animal rooms. In instances where biological agents may produce infection in humans, the Chemical and Biological Safety Committee advises the principal investigator of the immunization requirements and entry policies. Principal investigators may petition the Committee regarding their specific research proposals.
  4. When an infectious agent in use in the laboratory requires special provisions for entry, such as vaccination, a hazard warning sign, incorporating the universal biohazard symbol, shall be posted on the access door to the laboratory work area. The hazard warning sign shall include the following:
    • Identification of the infectious agent,
    • Name and telephone number of the principal investigator or other responsible person(s),
    • The special requirement(s) for entering the laboratory.
  5. An insect and rodent control program is in effect.
  6. Laboratory coats, gowns, smocks, or uniforms shall be worn while in the laboratory. Before leaving the laboratory for non-laboratory areas, such as the cafeteria, library, or offices, this protective clothing shall be removed and left in the laboratory, or it is covered with a clean coat not used in the laboratory.
  7. Animals not involved in the work being performed are not permitted in the laboratory.
  8. Special care shall be taken to avoid skin contamination with infectious materials; gloves shall be worn when handling infected animals and when skin contact with infectious materials is unavoidable.
  9. All wastes from laboratories and animal rooms shall be appropriately decontaminated before disposal. Orange or orange-red bags shall be used to contain solid waste prior to decontamination. Following the decontamination procedure, waste shall be overpacked into a bag of another color for disposal as non-hazardous.
  10. Hypodermic needles and syringes shall be used only for parenteral injection and aspiration of fluids from laboratory animals and diaphragm bottles. Only needle-locking syringes or disposable syringe-needle units (i.e., the needle is integral to the syringe) shall be used for injection or aspiration of infectious fluids.

    Extreme caution shall be used when handling needles and syringes to avoid autoinoculation and the generation of aerosols during use and disposal. Needles shall not be bent, sheared, replaced in the sheath or guard, or removed from the syringe following use. The needle and syringe shall be promptly placed in a puncture-resistant container and decontaminated, preferably by autoclaving, before discard or reuse.
  11. Spills and accidents which result in overt exposures to infectious materials shall be immediately reported to the principal investigator. Medical evaluation, surveillance, and treatment shall be provided as appropriate, and written records shall be maintained by the department head.
  12. When appropriate, considering the agent(s) handled, baseline serum samples for laboratory and other at-risk personnel shall be collected and stored. Additional serum specimens may be collected periodically, depending on the agents handled.
  13. Personnel shall be advised of special hazards and required to read appropriate sections of this document on practices and procedures and to follow them.
  14. The principal investigator shall ensure that laboratory cleaning of work surfaces is performed in a manner appropriate to the agents being used and stored in the laboratory.
Containment Equipment - BL2

Biological safety cabinets Class I or II or other appropriate personal protective or physical containment devices shall be used whenever:

  1. Procedures with a high potential for creating infectious aerosols are conducted. These may include centrifuging, grinding, blending, vigorous shaking or mixing, sonic disruption, opening containers of infectious materials whose internal pressures may be different from ambient pressures, inoculating animals intranasally, and harvesting infected tissues from animals or eggs.
  2. High concentrations or large volumes of infectious agents are used. Such materials may be centrifuged in the open laboratory if sealed heads or centrifuge safety cups are used and if they are opened only in a biological safety cabinet.
Laboratory Facilities - BL2
  1. The laboratory shall be designed so that it can be easily cleaned.
  2. Bench tops shall be impervious to water and resistant to acids, alkalies, organic solvents, and moderate heat.
  3. Laboratory furniture shall be sturdy. Spaces between benches, cabinets, and equipment shall be accessible for cleaning.
  4. Each laboratory shall contain a sink for handwashing.
  5. If the laboratory has windows that open, they shall be fitted with fly screens.
  6. An autoclave for decontaminating infectious laboratory wastes shall be available.


Page Updated 11.22.2017