Many biological safety cabinets are equipped with ultraviolet (UV) lights. However, if good practices are followed, UV lights are not needed to protect tissue culture or other work. UV radiation should not take the place of wiping down the cabinet interior with a disinfectant or the practice of good aseptic technique. If you wish to use UV lamps, acquaint yourself with their limitations and hazards.
- UV is effective only when it directly hits a microbial cell. Cells/spores may be protected from UV radiation by dust or organic matter. Likewise, UV lamps must be cleaned regularly to remove any dust and dirt that may block its germicidal effectiveness. Turn off the light and wipe it with 70% ethanol every two weeks. Lights need to be replaced periodically. The length of time a lamp will be effective depends on the number of hours it is in use. Lamps should be checked periodically with a meter to ensure that the appropriate intensity of UV light is being emitted.
- UV light does not penetrate cracks or seams so will not disinfect the spill area under the work surface - a favorite hideout for fungal spores.
- Due to mercury content UV lights need to be disposed of as hazardous waste.
- Turn off UV light when the room is occupied - UV exposure can burn corneas and cause skin cancer.
- Be aware that UV lights can cause gas line tubing to deteriorate and present a gas leak hazard.