Biosafety Manual

36 Biosafety Manual For more detailed information on BSC types and uses, see BMBL- Appendix A, “Primary Containment for Biohazards: Selection, Installation, and Use of Biological Safety Cabinets.” When Must I Use a BSC? Biosafety cabinets should be used whenever you are conducting lab procedures with biohazardous materials that may produce aerosols or anytime you are working with large amounts of infectious materials. A BSC must also be used for all manipulation of airborne-transmitted human pathogens, such as Brucella abortus and Mycobacterium tuberculosis, which are worked with at BSL-3. A biosafety cabinet is not a chemical fume hood. Chemical fume hoods are designed to protect personnel by removing chemical vapors and aerosols from the work area. Open Flames in a BSC Open flames, such as Bunsen burners, should never be used in a BSC. Open flames inside of a BSC disrupt the airflow, compromising protection of both the worker and the material being handled. Open flames are extremely dangerous around flammable materials, such as ethanol, which is often used in a BSC. Electric incinerators or sterile disposable instruments are excellent alternatives. Decontamination and Ultraviolet Lights in a BSC The BSC work area must always be cleaned and disinfected thoroughly before and after each use, using a chemical disinfectant such as an iodophor. Iodophors (Wescodyne) can be purchased through Central Stores. Be sure to allow adequate disinfection time for the disinfectant used. 70% alcohol evaporates too quickly to be effective and fumes can build up in the biosafety cabinet, creating an explosion hazard. If you use bleach as a disinfectant, be sure to follow by wiping with sterile water, as bleach will corrode the stainless steel of the biosafety cabinet. EH&S does not recommend the use of ultraviolet (UV) lights in a biosafety cabinet because of their ineffectiveness and safety risk. UV light has very little power to penetrate, even through a dust particle, so the UV light is not a method that should be used for primary decontamination. Note that UV lights lose effectiveness over time. Warning: Be sure the UV light is turned off before beginning work. Exposure to UV light for a prolonged period will cause skin, corneal, and/or retinal burns. Newer BSCs have safeguards to prevent personnel from being exposed to UV light; however, some older models may not have these safeguards. For most consistent contamination control and safe operation, biosafety