Evaluate the risk

After gathering all available information, risk evaluation should be performed. In this step, the likelihood of exposure to a hazard is weighed against the potential severity of harm under a set of predefined circumstances, such as a specific laboratory procedure. The main goal of a risk evaluation is to determine whether the assessed risk is acceptable, or whether further targeted risk control measures should be implemented to prevent or reduce the risks.

What is Likelihood? Likelihood is the probability of an incident (that is exposure to and/or a release of a biological agent) when conducting laboratory activities.

Factors that could increase the likelihood of an exposure to and/or release of biological agents during work in the laboratory: – Laboratory activities such as the procedures that can generate aerosols and larger airborne particles (droplets), as well as the use of sharps. – Procedures involving animals can present a number of hazards such as bites and scratches, exposure to zoonotic agents, and the handling of experimentally generated infectious aerosols. – Low competency of laboratory personnel – lack of experience and failure to comply with SOPs – Improper use of PPE that reduce its effectiveness – Safety equipment that is not working properly – Poor location, room air currents, decreased airflow, leaking filters, and crowded work surfaces.

What is Severity? The harm or adverse effect that may occur due to exposure to and/or release of a biological agent when conducting laboratory activities.

Factors that affect the severity of an incident are mainly depending on the biological agents, such as route of transmission and the infectious dose. For certain organisms, exposure to low quantities of the agent could cause an infection. When expose to larger quantities of the agents (greater than the infectious dose), it can significantly increase the severity of the infection. Next, the availability of effective prophylaxis or therapeutic interventions must be considered when determining the severity. Finally, when there is a large population of susceptible people or the agent is not endemic, the infection could spread more rapidly and infect larger numbers of people.

Establishing the Risk of a situation

To determine how likely an incident will happen and how severe the consequences, risk assessment matrix can be used. This matrix is useful to assess the relationship between likelihood and consequence in order to determine the initial risk of exposure to and/or release of a biological agent.

Is the risk acceptable? Once the initial risk has been evaluated, it is necessary to determine whether this risk is acceptable. If the risk score falls within the red cells, it is unacceptable for work to proceed safely. If risk score falls within lower yellow cells or green cells, then risk is typically acceptable. However, the risk acceptance is influenced by many factors, particularly determined by the regulation and legislation of an institution as well as its leadership.

If the initial evaluated risks are not acceptable, step 3 of the risk assessment framework should be performed.