Bl4 bsl requires the use of a supply line respirator or all work within a sealed totally enclosed glove box.
A set of biocontainment measures called a biosafety level (BSL), also known as a pathogen/protection level, is needed to isolate harmful biological agents in a lab setting. From the lowest biosafety level 1 (BSL-1) to the highest level 4, there are several levels of confinement (BSL-4). The Centers for Disease Control and Prevention (CDC) in the US have established these standards. The same biosafety levels are established by a directive in the European Union.
