Occupational Risk Assessment

Occupational risk assessment is the systematic process of identifying hazards in a work environment, estimating the likelihood and severity of harm they could cause to workers, and judging whether the resulting risk is acceptable or requires control. It is the analytic foundation on which workplace prevention decisions are built.

Definition

Occupational risk assessment is the structured evaluation of workplace hazards in which the probability and severity of potential harm to workers are estimated and compared with acceptability criteria to decide whether, and how urgently, controls are required.

Scope

The entry covers the steps of hazard identification, risk estimation by likelihood and severity, risk evaluation against acceptability criteria, and the documentation and review of the assessment. It treats occupational risk assessment as a methodological topic in occupational health and as the precursor to selecting controls, not as safety advice for a particular workplace.

Core questions

• What hazards exist in this workplace and who might be exposed?
• How likely is harm and how serious would it be?
• Is the estimated risk acceptable, tolerable, or unacceptable?
• When and how should the assessment be reviewed and updated?

Key concepts

• Hazard identification
• Likelihood and severity estimation
• Risk matrix
• Risk acceptability and tolerability
• Qualitative versus quantitative assessment
• Exposed populations and vulnerable workers
• Documentation and periodic review
• Residual risk

Mechanisms

The process typically proceeds in defined steps: hazards are first identified through inspection, task analysis, incident data, and worker input; the risk from each hazard is then estimated by combining the likelihood of an adverse event with the severity of its consequences, often using a qualitative risk matrix or, where data allow, quantitative methods. The estimated risk is evaluated against acceptability criteria to set priorities, and the assessment is documented and reviewed when work, equipment, or knowledge changes. International standards frame this as a generic risk-management cycle (ISO 31000) applied within occupational health and safety management systems (ISO 45001), where assessment feeds directly into the selection of controls.

Clinical relevance

Occupational risk assessment explains how worker exposures are anticipated and prioritised before harm occurs, which is useful background for clinicians evaluating work-related health and for public-health appraisal of occupational programmes. It describes a preventive analytic process and is not a prescriptive protocol for any individual workplace or worker.

Epidemiology

Risk assessment is a legal and management cornerstone of occupational safety and health systems internationally, reflected in the International Labour Organization's framework conventions and in management-system standards. Behavioural and organisational research, such as studies of why workers engage in unsafe behaviour on construction sites, shows that the accuracy of an assessment depends not only on technical hazard analysis but also on how work is actually performed, which assessments must capture to be valid.

History

Formal occupational risk assessment grew from industrial-hygiene and safety-engineering practice and was progressively codified through national occupational safety legislation and the International Labour Organization's 1981 Occupational Safety and Health Convention. The later publication of generic risk-management guidance (ISO 31000) and occupational health and safety management standards (ISO 45001) consolidated assessment into a standardised, auditable step within a broader management cycle.

Debates

Do risk matrices reliably represent real risk?

Qualitative risk matrices are widely used for their simplicity but are criticised for compressing very different hazards into the same category and for being sensitive to how likelihood and severity bands are defined, prompting debate over when quantitative methods are warranted.

How well do assessments capture real work?

Because risk depends on how tasks are actually carried out, assessments that ignore observed unsafe behaviour and informal work practices may underestimate exposure, so behavioural and organisational factors are increasingly treated as part of valid assessment.

Seminal works

• ilo-1981-c155
• iso-31000-2018
• iso-45001-2018

Frequently asked questions

What are the basic steps of an occupational risk assessment?

Identify the hazards, decide who might be harmed and how, estimate the risk by combining likelihood and severity, decide on and prioritise controls, and record and periodically review the assessment.

How is risk different from hazard in this context?

A hazard is a source of potential harm, whereas risk is the estimated combination of how likely harm is and how severe it would be; assessment turns identified hazards into prioritised, evaluable risks.