Evaluating containment effectiveness of A2 and B2 biological safety cabinets.

Purpose: This study investigates the use of a canopy-connected recirculating class II type A2 biological safety cabinet (BSC) as an alternative to the B2 when preparing volatile, sterile compounded preparations. Selection of the appropriate BSC for processes that use subgram levels of volatile chemicals is difficult due to a lack of quantitative containment evidence by cabinet type. There is a perception that hazardous compounding must be done in a B2 cabinet due to the potential for vapors, and this study seeks to challenge that perception.