Risk assessment in biosafety


Before the start of any new activity or subsequent contained use, the user must prepare a risk analysis using the assessment elements listed in Annex 5.51.3 of Vlarem II[1]. The objective is to estimate the nature and extent of the risks of a given situation (a priori analysis). A risk is defined here as an undesirable event, which it is not certain will occur. A risk is classically 'quantified' using the following formula:

risk = probability x effect

i.e. the multiplication of the probability of an undesirable event occurring and the magnitude of the potential damage.

The regulations are aimed at limiting the risks to people and the environment as far as possible and should, with regard to both pathogens and GMOs, be considered as an application of the precautionary principle.

In the case of biotechnological activities, however, such risk is difficult to calculate because it involves the probability of escape, the probability of getting into the right niche for survival and growth, and the probability of transferring genetic information. The consequences may be biological pollution, the creation of new organisms and thus the disruption of existing equilibria. What exactly the disruption of an equilibrium may entail over time is largely unknown.

A biotech risk analysis therefore often uses hazard identification, risk assessment and risk management:

  • hazard identification: determination of potential undesirable events that may occur.
  • risk evaluation: estimation of the probability or likelihood that those undesirable events may actually occur.
  • risk management: proposal of measures that can be taken to prevent undesirable events from occurring or to limit their impact.

Hazard identification and risk assessment should be based on a worst case scenario, which de facto leads to high risk management. However, as more data become available in practice, the risk analysis can be adjusted (a posteriori approach). If it turns out that the risk has been overestimated, the management measures can be reduced accordingly, and vice versa.

Making a risk analysis

Identification of the hazard for humans and the environment

The term hazard refers to the intrinsic property or capacity of an object, substance, process or situation to threaten the safety or health of employees or to cause adverse effects on the environment. Hazardous properties should be sought in:

  • the intrinsic hazard of the biological agents
  • use of agents, equipment, etc.
  • transport of biological agents
  • ...

In the exercise of biotech activities, it is mainly the biological agents present that are decisive in determining the containment level and containment measures. Agents are classified into pathogens and genetically modified organisms (GMOs). Pathogens are non-genetically modified organisms that can cause disease in humans, animals or plants to a greater or lesser extent, whereas with GMOs the genetic material is altered in a way that is not possible by nature.

As possible adverse effects should be considered:

  • diseases in humans, including allergenic or toxic effects
  • diseases in animals or plants
  • harmful effects resulting from the impossibility of treating a disease or providing an effective prophylaxis
  • adverse effects resulting from establishment or dissemination in the environment
  • harmful effects resulting from the natural transfer of inserted genetic material to other organisms
  • ...

Risk classes

The main criteria in determining the risk class of an organism are:

  • the importance of the disease being induced and the severity with which it may occur
  • the infectious potential, the virulence of the strain, the infectious dose and the mode of transmission
  • the spectrum of specificity of the target species
  • biological stability
  • power of survival and dissemination in the community or in the environment
  • the availability and effectiveness of prophylactic or therapeutic agents
  • ...

Three additional criteria apply to the classification of risk to plants:

  • the frequent occurrence of the host organism in Belgium
  • the presence of a target species in the vicinity of the installation or at the site where the installation's waste is disposed of
  • the exotic nature of the organism.

For pathogens (bacteria, fungi, viruses, etc.), Vlarem II provides lists to guide classification. These are organisms that in their natural form pose a biological risk, both to immunocompetent humans and/or animals and to healthy plants. In each case, the maximum attributed biological risk is reported which serves as the basis for the risk analysis. In addition, a list of organisms whose use is subject to the provisions of the federal decrees on the control of harmful organisms for plants and plant products is also given. If an organism is not assigned to a risk class, the organism must be classified by the user.

No lists are available for genetically modified organisms because of the very large number of possibilities. The Flemish Inter-University Institute for Biotechnology (VIB) provides schemes from which a first identification of the containment level can be derived: www.vib.be/NR/rdonlyres/95A93043-0A26-4742-861A-ACF54A58C5A7/0/Bioveiligheid.pdf. Since the possibility of unknown factors and mechanisms exists, the risk must be estimated higher than for similar, unmodified organisms.

Based on these characteristics, organisms are classified into risk classes, also called biological containment:

  • Category 1: includes organisms, recognized as non-pathogenic to humans, animals and plants and not harmful to the environment or with a negligible risk to humans and the environment on a laboratory scale. This class includes, in addition to organisms of proven harmlessness, strains that may be allergenic and opportunistic pathogens
  • Category 2: includes organisms that can cause disease in humans, animals or plants, but with limited geographical, economic and/or medical impact. Prophylactic measures or effective (therapeutic) treatment are usually available for pathogens of risk class 2 in humans, animals and plants.
  • Category 3: includes organisms that can cause serious epizootics in humans, animals or plants. The risk of spread in the community (human), of transmission between different species (animal) or of adverse effects on the economy and the environment (plant) is important. For human and animal pathogens of risk class 3, the treatment may be very expensive, difficult to apply or even non-existent
  • Category 4: includes organisms that can cause serious disease in humans with a real risk of spreading, and an extremely serious panzoonotic or epizootic disease in animals, with profound economic consequences for the affected growing regions. There is usually no medical prophylaxis or effective treatment. For animal pathogens of risk class 4, one exclusive sanitary prophylaxis may be possible or mandatory.

Furthermore, the way in which a possible contamination can occur through a manipulation should be investigated (way of transfer, entry routes). Here the type of organism with its specific hazards is of great importance.

Access can occur via direct or indirect transfer. A needlestick injury is an example of direct transfer; indirect transfer mechanisms are:

  • material transfer (vehicle-borne): transfer via water, food, blood, tissue objects, ...;
  • vector transfer (vector-borne): transfer by insects, rodents, ...
  • air transmission (air-borne): ingestion occurs by inhalation.

An important point of attention here concerns actions in the open phase. At that moment there is no physical barrier between the organism, the operator and the environment, which considerably increases the risk of contamination and spread.

Containment measures

Risk classes and possible modes of contamination determine the way of working in a biotech lab. Based on the classification of the risk level of a biological activity, requirements are imposed that determine the containment or physical containment of the laboratory equipment and infrastructure and recommend the course of action or safe technique in the laboratory. Four risk levels are distinguished that are defined in Art§2 Vlarem II, as follows:

  • risk level 1: activities that pose no or negligible risk
  • risk level 2: activities of low risk
  • risk level 3: activities presenting some risk
  • risk level 4:-activities that pose a high risk.

Containment measures for an activity are classified into four levels, analogous to the classification into risk levels. This concerns technical characteristics, safety equipment, working practices and waste management in laboratories (L), animal houses (A), greenhouses and growth chambers (G), as well as in sick rooms and areas with special hazards (HR), listed in table form (Annex Vlarem II):

  • L1/A1/G1/HR1: activities of risk level 1
  • L2/A2/G2/HR2: risk level 2 activities
  • L3/A3/G3/HR3: Risk level 3 activities
  • L4/A4/G4: risk level 4 activities.

Definition and determination of risks to humans and the environment

This involves identifying the circumstances under which the likelihood of harmful effects is considered real. The harm, as being any impediment to physical and psychological proper functioning of a human individual and/or degradation of the environment can be described in terms of:

  • severity: physiopathology, complications, incapacitation, spread of GMO, etc.
  • frequency

In order to minimize this damage, it is essential to obtain a view of the risks present within the institution and to evaluate their importance. To this end, as well as to assess the interrelationships, the EFA methodology is used, translated into the following formula:

severity (E) x frequency (F) x number of exposed persons (A)

i.e. the multiplication of the severity, exposure time and number of exposed persons at the occurrence of a risk.

Bottleneck identification

The aim is to list manipulations that pose a risk to the safety, health and/or other working conditions of the worker. In this context, checklists are used that present all possible risks (e.g. as a combination of hazards and conditions) in a structured manner.

Bottleneck analysis

For each bottleneck identified, the causes, consequences and number of exposed persons are determined. This is the input data for the evaluation.

Evaluation of the risks to people and the environment.

To get a picture of the impact of a bottleneck, it is weighted according to the three EFA parameters defined above, applied to the naked risk. To this end, the following value scales are used:

E: severity

degree to which a risk is an impediment to the correct execution of a manipulation
1 rather a detail;
2 minor bottleneck;
3 medium bottleneck
4 important bottleneck, but not essential;
5 essential bottleneck.

F: frequency

measure of the number of exposures per unit of time to a risk
1 rarely (once a month to a year);
2 regularly (once a week to a month);
3 very frequent (daily to several times a week).

A: number of persons exposed

maximum number of persons who may be exposed simultaneously to a single risk
1 1 to 3;
3 4 to 10;
5 >10.


Doability index

In addition to assessing the risk according to the EFA method, the degree to which it is technically possible to solve or reduce a bottleneck, i.e. the doability, should also be examined:

D: doability

degree to which it is technically possible to solve or reduce a bottleneck
0 the problem is completely unsolvable, it cannot be solved;
1 solving the problem seems very difficult;
3 the problem is solvable with some effort;
5 the problem is very solvable bottleneck.

This doability index is of particular importance in an academic setting because it allows for correction for the unwieldy decision-making process and inadequate funding policies of non-core business matters.

Risk Management

The assessment of a risk is then done on the basis of both scores explained above and serves to support risk management:

  • multiplying the parameters severity, frequency and number of people exposed (EFA)
  • feasibility index

Risk management should thus lead to risk control, whereby the probability of unwanted exposure during a manipulation should be reduced or prevented, or whereby the adverse consequences of an exposure should be as limited as possible.


Risk analysis should not be confused with the measurement of exposure to harmful substances and its comparison with threshold values. Exposure can be measured and expressed in a figure, e.g. concentration in ambient air, exposure during x consecutive working hours, noise exposure during a working day of x hours, etc.. Exposure testing, including testing against limit values, can be standardized; standards have been published. Such tests can be an essential part of the risk analysis, but the test itself is not a risk analysis.

Web References

  • http://www.ogtr.gov.au/pdf/moncomp/riskanapro.pdf
  • http://agbiosafety.unl.edu/paradigm.shtml
  • http://agbiosafety.unl.edu/paradigm2.shtml
  • http://www.istge.it/library/libri/safeman/istpdfeng.pdf
  • http://www.bioveiligheid.be/PDF/BesVG04_NL.pdf
  • http://www.oie.int/eng/maladies/en_classification.htm (quarantine organisms)
  • http://www.vib.be/NR/rdonlyres/95A93043-0A26-4742-861A-ACF54A58C5A7/0/Bioveiligheid.pdf