How many BSL levels are there?
There are four biosafety levels. The levels define proper laboratory techniques, safety equipment, and laboratory design, all of which depend on the type of infectious agent being studied. The lowest level, BSL-1, describes the minimum precautions required for handling agents that generally do not cause disease in healthy humans. The highest level, BSL-4, describes the extensive precautions required for handling certain new agents and those known to cause serious disease for which there are no treatments or vaccines. For example, BSL-4 lab personnel are required to wear full-body, air-supplied suits and to undergo a decontamination shower whenever they exit the laboratory. Many U.S. institutions and companies with infectious disease research programs have BSL-3 laboratories. In addition, some hospital have small laboratory or clinical areas that can operate at the BSL-3 level, including space for isolating patients suspected or known to have certain highly contagious diseases. Thus, th
