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Important Information
Universal Precautions
Universal Precautions is the concept of treating all human/primate blood and other body fluids, tissues and cells (including cell lines) as if they were known to be infectious for bloodborne pathogens.
All human blood, blood products, unfixed human tissue and certain body fluids shall be handled with Universal Precautions and BSL – 2 practices.
Table 1. Basis for the classification of biohazardous agents by biosafety level.
| BSL 1 | Agents that are not associated with disease in healthy adult humans |
| BSL 2 | Agents that are associated with human disease which is rarely serious and for which preventive or therapeutic interventions are often available |
| BSL 3 | Agents that are associated with serious or lethal human disease for which preventive or therapeutic interventions may be available (high individual risk but low community risk) |
| BSL 4 | Agents that are likely to cause serious or lethal human disease for which preventive or therapeutic interventions are not usually available (high individual risk and high community risk) |
Table 2. Summary of laboratory facilities for BSL 1 – 4.
| BSL | Agents | Practices | Safety Equipment (Primary Barriers) | Facilities (Secondary Barriers) |
|---|---|---|---|---|
| 1 | Not associated with disease in healthy adults | Standard Microbiological Practices | As needed to allow for good microbiological practices |
Open bench top Sink required |
| 2 | Associated with human disease, hazard = percutaneous injury, ingestion, mucous membrane exposure | BSL – 1 practice plus: Limited access Biohazard warning signs “Sharps” precautions Biosafety manual defining any needed waste decontamination or medical surveillance policies |
Primary barriers: Class I PPE: laboratory coats; gloves; 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 | BSL – 2 practices plus: Controlled access Decontamination of all waste Decontamination of lab clothing before laundering Baseline serum |
Primary barriers: Class I or II BSC or other physical containment devices used for all open manipulations of agentsPPE: protective lab clothing, gloves, respiratory protection as needed |
BSL – 2 plus: Physical separation from access corridorsSelf-closing, double-door accessExhausted air not recirculated Negative airflow into laboratory |
| 4 | Dangerous/exotic agents which pose high risk of life-threatening disease, aerosol- transmitted lab infections, or related agents with unknown risk of transmission | BSL – 3 practices plus: Clothing change before enteringShower on exitAll material decontaminated on exit from facility |
Primary barriers: All procedures conducted in a Class III BSC, or Class I or II BSC in combination with full-body, air-supplied, positive pressure personnel suit | BSL – 3 plus: Separate building or isolated zoneDedicated supply and exhaust, vacuum and decon systemsOther requirements outlined in the text of the BMBL |
Universal Precautions include frequent hand washing, no mouth pipetting, no food or drink in the lab and proper disposal of biohazardous/ medical waste, as well as the use of engineering controls and personal protective equipment (PPE). Engineering controls include biosafety cabinets, ventilation systems, closed top centrifuge rotors, etc.; these are the primary methods to control exposure. PPE such as gloves, lab coats, and eye protection or face shields must be selected and used as appropriate. All material should be treated as medical waste (see Chapter 9).
Important Information
Wash Your Hands
At all Biosafety Levels your last line of protection is the SINK. After finishing all procedures and cleanup, wash your hands with soap and water.
Areas subject to Universal Precautions must have appropriate signs posted on doors and equipment; these signs can be obtained from EH&S (723.0448). Additional information on Universal Precautions is presented in Figure 2.
Biological agents are classified by Risk Group (RG); RG 1 being the least pathogenic to RG 4 being the most. The RG, together with the work to be done (experiments) is assessed to determine the Biosafety Level (BSL).
Important Information
Biosafety Levels
Risk Group (RG) 1 – 4 + Work (research) = Biosafety Level (BSL) 1 – 4
Historically agents are often referred to as BSL – 1-4 (vs RG1). Although this is not technically correct this manual stays with the norm and uses BSL regarding agents.
