Laboratory Biosafety

There are usually four levels of laboratory containment (based on WHO classifications) which are defined for pathogenic organisms (not just for genetically modified organisms) and are based on the hazard classification described elsewhere.

Level 1 is the lowest level or containment, and requires no extra precautions above those required for good microbiological practice. In general, this means that(12)

  • Laboratory personnel must be instructed in the procedures used in the laboratory.
  • The laboratory should be easy to clean. Bench surfaces should be impervious to water and be resistant to acids, alkalis, solvents and disinfectants.
  • If the laboratory is mechanically ventilated, an inward air flow into the laboratory should be maintained by extracting room air to the atmosphere.
  • The laboratory must contain a wash handbasin or sink that can be used for hand washing.
  • The laboratory door should be closed when work is in progress
  • Laboratory coats or gowns should be worn in the laboratory and removed when leaving the laboratory suite.
  • Eating, chewing, drinking, smoking, storing of food and applying cosmetics must not take place in the laboratory.
  • Mouth pipetting must not take place
  • Hands must be disinfected or washed immediately when contamination is suspected, after handling viable materials and also before leaving the laboratory.
  • All procedures must be performed so as to minimise the production of aerosols.
  • Effective disinfectants must be available for immediate use in the event of spillage.
  • Bench tops should be cleaned after use
  • Used laboratory glassware and other materials awaiting disinfection must be stored in a safe manner. Pipettes, if placed in disinfectant, must be totally immersed.
  • All waste material which is not to be incinerated should be rendered non-viable before disposal.
  • Materials for disposal must be transported without spillage in robust containers
  • All accidents and incidents must be recorded.

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The conditions for higher levels of containment, where the organism is considered a pathogen, are listed in the guidance note (see footnote ). For level 2, the major addition are the need to ensure that access to the laboratory is restricted to those needing to enter; that there be adequate space for each worker (at least 24 m3); an autoclave must be readily accessible and all waste materials must be made safe before disposal either by autoclaving or by incineration.

Table 1:

Summary of Laboratory Containment Requirements(13)

Level 1 Level 2 Level 3 Level 4
Laboratory suite: isolation No No Partial Yes
Laboratory: sealable for fumigation No No Yes Yes
Ventilationinward airflow/ negative pressure Optional Optional Yes Yes
through safety cabinet No Optional Optional No
mechanical: direct No No Optional Yes
mechanical: independent ducting No No Optional Yes
Airlock No No Optional Yes
with shower No No No Yes
Wash handbasin Yes Yes Yes Yes
Effluent treatment No No No Yes
Autoclaveon site No No No No
in suite No Yes Yes No
in lab: free-standing No No Optional No
in lab: double-ended No No No Yes
Microbiological safety cabinet / enclosure No Optional Yes Yes
Class of cabinet / enclosure - Class I Class I/III Class III

There will be risks to the environment for contained use of modified organisms as well. The escape of modified organisms used in laboratories should be of little significance as they should have been disabled so that, in the event of escape, they will be unable to survive. However, the assumption has been that the only concern is risk to human health and safety. The risk assessment has been predicated on this, and the possibility that the organism may be a danger to other organisms within the environment has not been fully considered in the discussion. The concept of the 'environment' which includes land, air and water as well as other organisms and humans, is so broad when compared to the enclosed environment of the laboratory that is it difficult to define a clear step-wise approach to risk assessment. The risk assessment must try to consider all possibilities of what could go wrong, and attempt to ensure that these cannot happen, largely through the design of the organism being used. Methods for retrieving the situation should an organism escape from containment become important, and need to be planned at the outset rather than relying on the containment procedures to work. This is particularly important where the organism is a Level 1 organism as it will not infect humans, but if it escapes could be disastrous to plants, insects or other animals.

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Biosafety Science


Biosafety Overview
Biosafety Details
Laboratory Biosafety
Exotic Introduction of Organisms

Last Modified: May 21, 2001
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