Abstract
The most critical point for the biosafety is not sophisticated devices or facilities, but education of workers and their compliance to the regulation. Appropriate devices should be carefully selected in the introduction of new devices, and they should be properly maintained. The class II biosafety cabinet is one of the delicate safety equipments. It should be kept adequately maintained throughout the lifetime of the cabinet to insure safety of the laboratory. For the maintenance, appropriate measuring equipments should be used by trained technicians. The recently enforced law for control of recombinant DNA researches should be applied for the handling of pathogens even in non-recombinant DNA researches after proper modifications.