Biosafety in the laboratory - VIB

Containment at the source
As is the case for any other activity that may present a risk, one should always try to tackle
the risk at its source. Among other things, this means that one should always opt for organisms,
host organisms or vectors presenting less risk, but providing the same results as
their alternatives that do pose a threat. In order to achieve containment at the source,
researchers should, if possible:
•use a biologically contained or attenuated laboratory strain instead of a
wild-type strain,
•use a non-mobilisable vector instead of a self-transmissible one,
•use a replication-defective virus or viral vector instead of a
replication-competent one.
Physical containment
Physical containment comprises all physical measures that are taken to protect organisms
from the surrounding environment and vice versa. This starts with the container holding
the organism (for instance, a tube), but it also comprises the structure, floor, walls, ceiling,
doors and windows of the laboratory, as well as benches that are suitable for working with
pathogenic organisms or genetically modified micro-organisms. To allow the handling of
micro-organisms, the benches should have a smooth surface and be readily decontaminable.
A sink should be present to allow laboratory staff to wash their hands after an experiment.
When a higher containment level is required (2,3 or 4), a number of additional physical
containment measures will be taken (depending on the risk the activity represents),
such as:
• class I, II or III safety cabinets
• negative air pressure in the laboratory
• an air-lock
•a shower
• HEPA filtration of the exhaust air
•special cups and other equipment to prevent the spread of aerosols
• gas-tightness of the laboratory to permit gas decontamination
• etc.
An overview of all legally required physical containment measures is listed in annex 1.
Safety cabinets
A safety cabinet is an important type of physical containment. In fact, a safety cabinet
creates a safe working space within the laboratory. Safety cabinets are designed to protect
the worker in the first place and the environment in the second place. A distinction is
made between three types of safety cabinets: class I, II and III. A class I cabinet is a fume
hood in which exhaust air passes through a HEPA filter. This type of cabinet provides worker
protection, but no experiment protection.
Containment: a combination of infrastructure and working practices 21