What are the benefits of using a 4x4 risk matrix?

Catastrophic (the hazard is capable of causing death and illness).

Critical (the hazard can result in serious injury or illness, property or equipment damage).

Marginal (the hazard could cause illness, injury, or equipment damage but its effects would not be serious).

Negligible (the hazard will not result in serious injury or illness, or has a remote possibility of damage).

Frequent (likely to occur, to be expected).

Probable (not surprised, will occur in given time).

For more information on how to perform a risk assessment, see our more detailed guide.Ī 4x4 risk matrix contains 4 levels of probability and severity.įor example, a standard 4x4 matrix has the following values: Likelihood

Probable: Likely to occur often during standard operationsīy multiplying a hazard's probability and severity values, you can calculate the acceptability level of its risk.Occasional: Likely to occur some time during standard operations.Improbable: Unlikely but possible to occur during standard operations.Critical: The hazard may commonly cause death or major system loss, requiring immediate cessation of the unsafe activity or operation.

Moderate: The hazard may commonly cause severe injury or illness or major system damage, requiring immediate corrective action.Marginal: The hazard may either be controlled, or would commonly result in less than minor, illness, injury or system damage.A 3x3 risk matrix has 3 levels of probability and 3 levels of severity.įor example, a standard 3x3 risk matrix contains the following values: Severity: EHS workers assess risks by evaluating the severity of a potential hazard, as well as the probability that it will occur.Ī risk assessment matrix contains a set of values for a hazard’s probability and severity. As a refresher, a risk matrix is a tool that safety professionals use to assess the various risks of workplace hazards.

Cons of risk register