A BSC Class I is a ventilated cabinet that offers protection to personnel, as well as the environment, is considered to be a Class I cabinet. Class I cabinets do not provide any form of protection for products against contamination, which significantly limits the range of applications for these cabinets. They employ uncirculated airflow in the opposite direction of the operator. Class I cabinets have an airflow pattern that is comparable to that of a fume hood, but in addition, the exhaust outlet of these cabinets is equipped with a HEPA filter. They might be ducted outside or they might not be. Class I cabinets can be utilized without risk when working with agents that require containment at Biosafety Levels 1, 2, or 3.

These cabinets are used to protect scientists, the environment and products from biohazards and cross-contamination during routine procedures. Other products associated with Biological safety cabinets are Laminar air flow equipment and clean room/clean air technology