A half century has passed since class II biological safety cabinets (BSCs) have been introduced into the biomedical research laboratories in the United States. Various new technologies have been adopted to improve the performance of BSCs in the history. National Sanitation Standard No. 49 (currently NSF/ANSI Std. No. 49) has been used to standardize the specification of BSC. European standard EN12469 and BS 5726 have well coordinated feature with the NSF/ANSI Std. No. 49, although there are some minor modifications. Japanese standard JIS K 3800:2009 has also similar content, with minor modifications.