Biosafety Cabinet Usage Guidelines

• See Biosafety Cabinet Overview for a discussion of different types of biosafety cabinets, purpose, certification, and decontamination requirements.
• Don't use the top of the cabinet for storage; this can damage the HEPA filter.
• Keep only necessary equipment or supplies inside the BSC.

• Wear personal protection equipment (PPE):
  • Labcoat
  • Gloves
  • Safety glasses
• Place materials in the cabinet before beginning work if possible.
• If the cabinet has an ultraviolet sterilizer, turn it off as soon as you enter the room.
• Turn on all blowers and cabinet illumination lights.
• Let the cabinet operate for about 5 minutes while you check the flow alarm system and visual alarm function (if applicable).
• Use an appropriate disinfectant to decontaminate the BSC's interior.

• Never have the ultraviolet light on when working at the cabinet. It can cause eye damage and skin burns.
• Avoid disrupting airflow:
  • Minimize movement (especially rapid movements) into and out of the BSC, or in areas near the BSC.
  • Don't block the front grill or rear vents with your arms or other materials.
  • Work at least 4 inches from the inside edge of the front vent.
• Don't use Bunsen burners inside a biosafety cabinet. Safer sterilization methods exist, such as touch-plate microburners equipped with a pilot light, small electric "furnaces," or pre-sterilized loops.
• Beware of fire hazards associated with vaporized ethanol and isopropanol disinfectants.

• EH&S Biosafety division strongly discourages UV lamps in BSCs.

  National Institutes of Health (NIH), Centers for Disease Control and Prevention (CDC), National Science Foundation/ANSI, and the American Biological Safety Association agree that ultraviolet (UV) lamps are not recommended or necessary for decontamination in BSC’s.

  If a UV lamp is used in your BSC, do the following:

• Required:
  • Post a warning sign on the front of the BSC indicating the presence of UV light hazards.
  • The sign must say CAUTION: Turn off UV light before working.
• Be aware of the hazards. Exposure to UV light can cause:
  • Painful eye and skin burns
    • Damaging exposure levels exist well after the output of the lamp bulb has dropped below the biocidal level.
  • Deterioration of some tubing
    • This can be dangerous if you're using a touch-o-matic burner with natural gas tubing in a BSC.
• Be aware of the limitations:
  • Never rely on UV irradiation alone to disinfect a contaminated work area. UV is:
    • Not effective on porous materials that are opaque to the light such as wood or foam
    • Ineffective if a microbe is protected by dust, dirt, or organic matter
    • Affected by the accumulation of dust and dirt on the bulb surface
    • Effective only in direct line of site
      • UV does not work in shadowed areas, penetrate into cracks or through the grill work of a BSC. The spill area under the work surface of a BSC is a favorite hide out for fungal spore and hardy bacteria.
  • The UV lamp bulb remains lit long after the germicidal effectiveness is gone.
• Take precautions during work:
  • Turn off UV lamps while the lab is occupied. The stainless steel interior of the BSC can reflect potentially hazardous illumination out of the opening of the cabinet.
  • Never have the UV lamp on while an operator is working in the cabinet.
• After work is complete:
  • Turn the fan off and close the sash, if possible, when the UV lamp is on.
• Notes:
  • Clean UV lamp bulbs frequently by turning off the UV lamp then wiping off the surface of the room temperature lamp bulb with 70% alcohol.
  • Before replacing bulbs, clear the BSC of equipment and material, and disinfect it with 10% bleach and then clean with 70% ethanol.
  • Install the bulb with gloved hands to prevent oil build up.
  • Disinfect lamp bulbs before disposal as universal waste.

When you're done:

• Decontaminate all items inside the work area.
• Decontaminate the cabinet interior with an appropriate disinfectant.
• Never rely on UV irradiation of the work area alone to disinfect a contaminated work area.
• Operate the cabinet for about 5 minutes before turning off the blower.

• Decontamination and Sterilization, Office of Research Safety, Dept. of Occupational Health & Safety
• Laboratory Safety: Principles and Practices, Diane O. Fleming, Debra Hunt, 3rd ed., ASM Press
• Primary Containment for Biohazards: Selection, Installation, and Use of Biological Safety Cabinets (PDF), U.S. Dept. of Health and Human Services Public Health Services, Centers for Disease Control and Prevention and National Institutes for Health, 2000.