Risk Assessment

Back to all safety programs

Overview

A structured process to judge harm, its likelihood and the controls needed.

A hazard can cause harm; risk combines its likelihood and severity.

Hazard vs risk

Hazard — anything that can cause harm.
Risk — the likelihood combined with the severity of harm.
Risk rating = Likelihood x Severity on a 5x5 matrix.

Step-by-step procedure

Identify the hazards in each step of the task.
Decide who or what could be harmed, and how.
Evaluate the risk — score likelihood and severity.
Decide controls using the hierarchy of control.
Reduce the risk to ALARP.
Record the assessment; link to JSA and method statement.
Communicate the controls to everyone involved.
Review when the task, equipment or law changes, or after an incident.

The risk matrix

Likelihood \ Severity	Minor	Moderate	Major
Likely	Medium	High	High
Possible	Low	Medium	High
Unlikely	Low	Low	Medium

Hierarchy of control

Elimination — remove the hazard completely.
Substitution — replace with something safer.
Engineering controls — guards, barriers, ventilation.
Administrative controls — procedures, permits, training.
PPE — the last line of defence.

Roles & responsibilities

Role	Responsibility
Supervisor / Assessor	Leads the assessment, scores risk, selects controls.
Workers	Provide input on real hazards; confirm controls work.
HSE	Reviews and approves; verifies it stays current.

Common mistakes to avoid

Jumping to PPE instead of working down the hierarchy.
A generic assessment that doesn't match the real task.
Never reviewing it after a change or incident.

Legal requirements (Thailand)

Occupational Safety, Health and Environment Act B.E. 2554 (2011) — the governing workplace-safety law in Thailand.
Employers have a duty to assess and control work risks before work begins.
Ministerial Regulation on the standard for a safety management system B.E. 2565 (2022).

Frequently asked questions

What is Risk Assessment?

A risk assessment is the structured process of looking at a task, identifying what could cause harm, judging how serious and how likely that harm is, and then deciding what controls are needed to reduce the risk to an acceptable level. It is the foundation that every other safety control — the JSA, the method statement and the permit — is built upon.

Who is responsible?

Likely: Medium; High: High; Possible: Low; Medium: High; Unlikely: Low; Low: Medium

What are the most common mistakes to avoid?

Jumping straight to PPE instead of working down the hierarchy from elimination. Writing a generic assessment that does not match the actual task on site. Never reviewing the assessment after the task, equipment or law changes.

References — ISO 45001:2018 risk concepts; Thai OSH Act B.E. 2554 (risk-assessment duty) and related regulations.