Biosafety Level
Laboratory Biosafety
Level criteria are described in "Biosafety in the Microbiological and Biomedical
Laboratories", CDC/NIH, 1993 (HHS Publication No. (CDC) 93-8395). Biosafety
levels (BSL) 1 through 4 employ a combination of standard microbiological practices,
safety equipment and facilities to protect the worker, environment and product. A summary
of criteria for the biosafety levels is shown in the table below.
Biosafety levels are based on the organism and the type
of procedure performed with the organism. Standard clinical laboratory manipulaiton of M.
tuberculosis warrants BSL-2 procedures and facilities whereas, culturing or
propagating the organism requires BSL-3 procedures and facilities. Therefore, a minor
change in procedure with certain agents such as culture, incubation or aerosol generation
may increase the biosafety level criteria necessary to perform the procedure.
Bio-
safety Level |
Agents |
Practices |
Safety Equipment
(Primary Barriers) |
Facilities
(Secondary Barriers) |
| 1 |
Agent not known to cause disease in
healthy adults |
Standard microbiological practices |
None required |
Open bench top, sink required |
| 2 |
Associated with human disease,
hazard = autoinnoculation, ingestion, mucous membrane exposure. Examples: blood and blood products, Mycobacterium
tuberculosis, Legionella pneumophila. |
BSL-1 practices plus:
+Limited access
+Biohazard warning sign
+Sharps precautions
+Biosafety manual defining any needed
waste decon or medical surveillance policies |
Primary barriers = Class 1 or 2 BSCs
or other physical containment devices used for all manipulations of agents that cause
splashes or aerosols; PPE - lab coats, gloves and face protection as needed. |
BSL-1 plus:
+Autoclave available |
| 3 |
Indigenous or exotic agents
with potential for aerosol transmission; disease may have serious or lethal consequences. Examples: Production quantities or manipulation of cultures
of BSL-2 agents. See the reference for specific agents. |
BSL-2 practices plus:
+Controlled access
+Decon all waste
+Decon lab clothing before laundering
+Baseline serum |
Primary barriers = Class 1 or 2 BSC's
or other physical containment devices used for all manipulations of agents; PPE -
protective lab clothing, gloves, respiratory protection as needed. |
BSL-2 plus:
+Physical separation from access corridors
+Self-closing, double door access
+Exhausted air not recirculated
+Negative airflow in lab |
| 4 |
Dangerous/exotic agents which
pose high risk of life-threatening disease, aerosol transmitted lab infections, or related
agents with unknown risk of transmission. Examples:
Marburg, Ebola. |
BSL-3 practices plus:
+Clothing change before entering
+Shower on exit
+All material decontaminated on exit from lab
|
Primary barriers = All procedures
conducted in Class 3 BSC's or Class 1 or 2 BSC's in combination with full body, air
supplied positive pressure personnel suit. |
BSL-3 plus:
+Separate building or isolated zone
+Dedicated supply/exhaust, vacuum, and decon systems
+Other requirements outline in the reference. |
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Laboratory Biosafety |
