The safe handling of biological materials, particularly infectious agents which are classified on the basis of degree of risk to humans working with them and includes definition of biosafety levels for handling such agents. Level 1: standard microbiological practices; Level 2: Level 1 plus laboratory coats, decontamination of waste, restricted access, gloves, biohazard warning signs; Level 3: Level 2 practices plus special clothing and controlled access; Level 4: Level 3 practices plus change room access where all street clothing and accessories are removed and replaced with laboratory clothing or special half or full suits with independent air supply; all waste is decontaminated and personnel shower on exit.




