What are the 4 biosafety levels?

The four biosafety levels are:
– BSL-1: For agents not known to consistently cause disease in healthy adults; requires standard microbiological practices.
– BSL-2: For agents that pose moderate hazards; requires limited access, biohazard warning signs, and use of personal protective equipment (PPE).
– BSL-3: For agents that can cause serious or potentially lethal diseases through inhalation; requires controlled access, decontamination of all waste, and specialized ventilation systems.
– BSL-4: For agents that pose a high risk of life-threatening disease; requires complete isolation, full-body air-supplied suits, and specialized facilities.