What are the various biosafety levels and what does each one imply?
Biosafety levels provide guidelines for practices, safety equipment, and facility layout to ensure safe handling of materials in biological laboratories.(1) There are four biosafety levels (BSL), which have increasingly stringent security and containment practices. The safety levels are determined based on the agents used in research and the ways they affect the human population. Level 1 facilities have the fewest requirements for safety equipment, while Level 4 facilities have the most. In brief, the agents used, safety equipment, and secondary barriers in the facilities for each level breakdown as follows. Level 1 is not known to cause health problems in human adults (with the possible exception of the elderly and adults with immune system deficiencies). No safety equipment is required, though facilities must have sinks for hand washing. Level 2 facilities research agents that are associated with human disease; hazards are restricted to ingestion and mucous membrane exposure. Safety
