Design modifications of a class II biological safety cabinet and user guidelines for enhancing safety.

Class II Biological Safety Cabinets (BSCs) are widely used in biological and chemical research for protection of the investigator, the environment, and the project. However, researchers' operational procedures are often inconsistent with BSC design limitations. While the Class II BSC is only a partial containment cabinet, better design and user training can improve containment, thereby increasing personnel protection. The authors developed design modifications for a Class II BSC to permit internal waste collection and to optimize the available work area. An internal recessed well for the waste receptacle, relocation of petcocks and electrical duplex, and installation of a new vacuum bottle make operation of the cabinet more efficient and potentially safer. To correct poor work practices, which can compromise the protective features of any BSC, precise guidelines and training programs should be relied on. Standardization of guidelines for operation of BSCs would be beneficial to the clinical and research community, given the frequent exchange of investigators among biomedical institutions.