Biosafety is a major concern in laboratories handling pathogens. Containing hazardous agents in an effort to reduce or even eliminate the possible exposure of laboratory workers and others is a goal of biosafety. Four biosafety levels were developed to protect against agents such as bacteria, fungi, parasites, prions, rickettsial agents, and viruses (the most important group). These four levels include:
BSL-1 laboratories study agents not known to consistently cause disease in otherwise healthy adults, whereby no special equipment is required and basic safety protocols are followed.
BSL-2 laboratories test for moderate-risk agents that pose a risk if swallowed, inhaled, or in contact with the skin, whereby gloves, eyewear, handwashing, and decontamination facilities are used.
In BSL-3 laboratories, airborne, potentially lethal agents are studied. In these laboratories, gas-tight enclosures, specialized ventilation, and sealed windows are employed as well as clothing decontamination procedures.
The BSL-4 laboratories are used for high-risk, life-threatening diseases for which there are no vaccines or treatment. In BSL-4 laboratories, personnel are required to wear full-body, air-supplied suits and shower when leaving the laboratory.