| 1 |
Agents not known to consistently cause disease in healthy adults. |
Standard microbiological practices. |
None required. PPE: laboratory coat, gloves, eye protection as needed. |
Open bench top; sink required. |
| 2 |
Agents associated with human disease. Percutaneous or mucosal exposure hazard. |
BSL-1 practice plus limited access, biohazard signage, sharps precautions. |
BSCs (Class I or II) for aerosol-generating work. PPE: coats, gloves, face protection. |
BSL-1 plus autoclave available. |
| 3 |
Indigenous or exotic agents with potential for aerosol transmission. Serious or lethal disease. |
BSL-2 practice plus controlled access, decontamination of all waste and clothing. |
BSCs for all open manipulations. PPE: respiratory protection as needed. |
Physical separation from access corridors; self-closing double-door access; directional inward airflow; exhaust not recirculated. |
| 4 |
Dangerous and exotic agents posing high risk of aerosol-transmitted, life-threatening disease; no vaccine or therapy. |
BSL-3 practice plus clothing change before entry, shower on exit, decontamination of all materials on exit. |
All work in Class III BSC or Class I/II BSC with positive-pressure suit. |
Separate building or isolated zone. Dedicated supply/exhaust, vacuum, and decontamination systems. |
| 5 |
Agents for which containment is required before the agent has been isolated or named. |
BSL-4 practice plus continuous two-person occupancy and logged verbal attestation on entry and exit. |
Suit with redundant closed-loop supply; secondary suit worn beneath the first. |
Facility maintained under sustained negative pressure relative to the surrounding pressure, including outdoors. |
| 6 |
Agents whose route of transmission has not been determined and is assumed to be all routes simultaneously. |
BSL-5 practice plus prohibition on the removal of any object, including the operator, once introduced. |
Full encapsulation with no external seams. Personnel decontaminated in situ and indefinitely. |
Containment volume with no penetrations. Services provided by induction only. |
| 7 |
Agents that remain hazardous after inactivation, sterilization, and incineration. |
BSL-6 practice plus documented refusal to acknowledge the agent by name in written record. |
Barrier of a material demonstrated to be impermeable to the agent, pending demonstration. |
Facility sited at a remove sufficient that no emergency responder can arrive during an event. |
| 8 |
Agents that have not yet been described and may not yet exist. |
BSL-7 practice plus perpetual containment. No scheduled decommissioning date. |
Suit rated to a pressure that has not been specified; PPE per this catalogue. |
Facility indistinguishable from its surroundings and constructed before the requirement for it was known. |