Step 2: Assess Risks
Overview
Risk assessment involves considering what could happen when someone is exposed to a hazard and the likelihood of harm occurring. This assessment helps determine how severe the risk is, which controls are needed, and how urgently action must be taken.
[!important] When Assessment Is Required Formal risk assessment is mandatory under WHS Regulations for specific high-risk activities including confined space entry, live electrical work, and diving work. For many well-known hazards with established controls, you may skip formal assessment and proceed directly to implementing proven control measures.
When Should a Risk Assessment Be Carried Out?
Assessment Is Required When:
Uncertainty About Outcomes: When there is uncertainty about how a hazard may result in injury or illness. For example, introducing new construction methods or materials where the risks are not fully understood.
Multiple Interacting Hazards: When a work activity involves multiple hazards that may interact to produce new or greater risks. For example, working in a confined space while using chemicals—the confined space amplifies chemical exposure risks.
Assessing Control Effectiveness: When changes at the workplace may impact the effectiveness of existing controls. For example, increasing production rates may make previously adequate ventilation insufficient.
Complex High-Risk Work: High-risk construction work as defined in WHS Regulations (Schedule 3) often requires detailed risk assessment before preparing Safe Work Method Statements (SWMS).
Assessment May Not Be Required When:
Well-Known Hazards with Established Controls: If a Code of Practice or industry guidance provides specific control measures applicable to your situation, you can implement those controls without formal assessment.
For example, the hierarchy of control for respirable crystalline silica is well established:
- Use water suppression or on-tool extraction when cutting or grinding
- Isolate workers from dust generation
- Provide fitted respirators
If these controls suit your circumstances, implement them without detailed assessment.
Identical Situations with Existing Assessments: An existing risk assessment may be reused if:
- All hazards, tasks, and circumstances remain identical
- No worker or other person will be exposed to greater, additional, or different risks
- The workplace has not changed since the assessment was completed
However, if any variable changes (different equipment, location, workers, or environmental conditions), conduct a new assessment.
How to Conduct a Risk Assessment
Risk assessment can range from a simple discussion with workers to detailed analysis using specialist techniques.
Step 1: Understand How Hazards Cause Harm
Most incidents result from a chain of events, not a single cause. Understanding this chain helps identify where to break it.
Example: Concrete Saw Blade Breakage
Chain of events:
- Saw blade becomes worn from extended use
- Operator does not notice wear during pre-start check
- Blade fractures during cutting
- Fragments strike operator and nearby workers
- Serious lacerations and eye injuries occur
Breaking this chain at any point reduces or eliminates the risk:
- Preventive maintenance schedule (prevents step 1)
- Enhanced pre-start inspection training (catches step 2)
- Blade guards and PPE (mitigates step 5)
Considerations When Analyzing Event Chains:
- Existing controls: Are current measures controlling all types of harm, or only some?
- Actual work practices: How is work really done, not just how procedures describe it?
- Abnormal situations: What happens during maintenance, breakdowns, or equipment failures?
- Health and safety control failures: What if ventilation stops working, or guards are removed?
[!tip] Work Through "What If?" For each step in a process, ask "What if this goes wrong? What happens next?" Document the sequence to identify control opportunities. See Appendix C of the Code of Practice: How to manage work health and safety risks for detailed examples.
Step 2: Determine the Severity of Potential Harm
Estimate how serious the harm could be by considering:
Type and Severity of Harm:
- Death or permanent disability: Electrocution, fall from height, structural collapse
- Serious injury or illness requiring hospitalization: Fractures, serious burns, acute chemical exposure
- Medical treatment beyond first aid: Lacerations requiring stitches, back strains
- First aid only: Minor cuts, bruises, minor strains
Factors Influencing Severity:
Magnitude of Exposure:
- Fall distance: 3 meters vs. 30 meters
- Chemical concentration: Diluted vs. concentrated substances
- Force of impact: Hand tool vs. mobile plant struck-by incident
- Duration of exposure: Brief noise exposure vs. full-shift exposure
Number of People Exposed: A crane collapse on a busy construction site could affect dozens of workers and members of the public, while a hand tool incident typically affects one person.
Onset of Harm:
- Immediate: Traumatic injuries from falls, struck-by incidents, electrocution
- Delayed: Occupational diseases from long-term exposure to silica, asbestos, noise, or psychosocial stressors
Cascading Failures: Could one failure lead to others? For example:
- Loss of power disabling ventilation in a confined space
- Fire spreading to stored combustible materials or gas cylinders
- Structural failure during demolition causing adjacent building collapse
Construction Examples by Severity:
| Hazard | Low Severity | Medium Severity | High Severity |
|---|---|---|---|
| Working at Heights | Minor strain from awkward posture on low platform | Fracture from fall from 2m scaffold | Death from fall from roof or through fragile surface |
| Silica Dust | Minor respiratory irritation from brief exposure | Chronic respiratory symptoms from ongoing exposure | Silicosis, lung cancer from long-term exposure |
| Mobile Plant | Bruise from minor contact with reversing vehicle | Crush injury from being pinned by plant | Death from being struck or run over by plant |
| Manual Handling | Minor muscle soreness | Back strain requiring medical treatment | Permanent spinal injury from lifting heavy/awkward loads |
Step 3: Determine the Likelihood of Harm Occurring
Estimate how likely it is that someone will be harmed by considering:
Frequency and Duration of Exposure:
How often is the hazard present?
- Continuous: Noise from constant operation of equipment
- Frequent: Daily use of power tools generating silica dust
- Occasional: Monthly confined space entry for inspections
- Rare: Emergency rescue from heights
How long are people exposed?
- Longer exposure increases likelihood of harm, especially for health hazards (noise, chemicals, ergonomic stressors)
Proximity to Hazard:
How close do people get to the hazard, and how many people?
- Workers operating plant vs. workers working nearby
- Excavation affecting workers in the trench vs. those at the surface
- Public footpath adjacent to construction site
Likelihood Ratings:
| Rating | Description | Frequency Indicator |
|---|---|---|
| Certain | Expected to occur in most circumstances | Happens daily or multiple times per day |
| Very Likely | Will probably occur in most circumstances | Happens weekly or several times per month |
| Possible | Might occur occasionally | Could happen monthly or several times per year |
| Unlikely | Could happen at some time | Might occur once per year or less frequently |
| Rare | May happen only in exceptional circumstances | Has not occurred in this workplace but has occurred in the industry |
Factors Affecting Likelihood:
Effectiveness of Current Controls: If existing controls are inadequate or inconsistently applied, likelihood increases. For example, traffic management signs and painted lines are less effective than physical barriers separating pedestrians from mobile plant.
Organizational Changes: Increased demand, tight deadlines, or seasonal peaks can increase likelihood:
- Fatigue from long hours reduces attention, increasing mistakes
- Rushing increases risk-taking behavior
- Resource shortages lead to workarounds bypassing safety procedures
Working Environment:
- Weather conditions: Wet surfaces increase slip risks, wind affects crane operations, extreme heat causes fatigue
- Confined spaces: Amplify chemical exposure risks and complicate emergency response
- Poor lighting or ventilation: Increases likelihood of errors and exposure to contaminants
Human Factors:
- Worker experience: New or young workers are more likely to make errors or not recognize hazards
- Training and competence: Inadequate training increases likelihood of unsafe practices
- Fatigue and stress: Reduce cognitive function and reaction time
- Individual differences: Some workers may be more susceptible to certain hazards (e.g., existing respiratory conditions and silica exposure)
[!example] Construction Likelihood Assessment Hazard: Mobile plant reversing on congested site
Without controls: Very likely—excavators and trucks reverse constantly, workers and pedestrians are frequently nearby, congestion makes collisions probable.
With basic controls (signage, high-vis clothing): Possible—likelihood reduced but pedestrians can still enter plant operating areas.
With comprehensive controls (physical barriers, exclusion zones, spotters, proximity alarms): Unlikely—multiple layers prevent pedestrian access to operating zones.
Step 4: Determine the Risk Level
Combine severity and likelihood to estimate the overall risk level:
Risk Matrix:
| Severity ↓ / Likelihood → | Rare | Unlikely | Possible | Likely | Almost Certain |
|---|---|---|---|---|---|
| Catastrophic (death, multiple serious injuries) | High | High | Extreme | Extreme | Extreme |
| Major (serious injury, hospitalization) | Moderate | High | High | Extreme | Extreme |
| Moderate (medical treatment) | Low | Moderate | High | High | Extreme |
| Minor (first aid) | Low | Low | Moderate | Moderate | High |
| Negligible (no injury) | Low | Low | Low | Moderate | Moderate |
Risk Level Action Priority:
- Extreme Risk: Stop work immediately. Implement immediate interim controls. Senior management approval required before resuming work.
- High Risk: Immediate action required. Detailed risk control plan with timeline. Cannot commence work until controls are in place.
- Moderate Risk: Action required within defined timeframe. Implement controls as part of planned work procedures.
- Low Risk: Manage with routine procedures. Monitor to ensure controls remain effective.
Practical Risk Assessment Approaches
Simple Discussion-Based Assessment:
Suitable for straightforward hazards with obvious controls. Conduct during toolbox talks:
- Identify the task and associated hazards
- Discuss "what could go wrong" and how serious it could be
- Discuss how often exposure occurs
- Agree on risk level and required controls
- Document the discussion and agreed controls
Take 5 Assessment:
Before starting a task, workers take five minutes to:
- Stop: Pause before commencing
- Look: Identify hazards in the immediate work area
- Assess: Determine the risk level
- Control: Implement controls or seek assistance if controls are inadequate
- Monitor: Watch for changing conditions
Suitable for routine tasks where workers are competent to recognize and control familiar hazards.
Detailed Risk Assessment:
Required for complex or high-risk construction work. May involve:
- Specialist advice: Engage hygienists, engineers, or safety professionals
- Scientific measurement: Noise monitoring, air quality testing, structural engineering analysis
- Detailed analysis tools: Fault tree analysis, bow-tie diagrams, hazard and operability studies (HAZOP)
Mandatory for specific high-risk activities like confined space entry or work near live electrical apparatus.
Recording Risk Assessments
Document your risk assessment to:
- Demonstrate compliance with WHS duties
- Communicate findings to workers and other duty holders
- Provide a basis for selecting controls (Step 3)
- Enable review when circumstances change
Minimum Information to Record:
- Hazards identified and where they are located
- Who is at risk (workers, contractors, public)
- Type and severity of potential harm
- Likelihood of harm occurring
- Overall risk level (extreme, high, moderate, low)
- Existing controls and their effectiveness
- Required actions and who is responsible
- Date of assessment and when review is due
A risk register template is provided at Appendix D of the Code of Practice: How to manage work health and safety risks.
Special Considerations for Construction
Safe Work Method Statements (SWMS):
For high-risk construction work identified in Schedule 3 of the WHS Regulations, a SWMS must be prepared before work commences. The SWMS must include:
- A description of the high-risk construction work
- Identified hazards arising from the work
- Risk assessment for each hazard
- Control measures following the hierarchy of control
- How controls will be implemented, monitored, and reviewed
The SWMS is a formal risk assessment document for high-risk construction work.
Multi-PCBU Coordination:
Construction sites typically involve multiple PCBUs (principal contractors, subcontractors, labor hire, suppliers). Risk assessment must consider:
- Interface risks: Where different PCBUs' work activities interact
- Shared controls: Who is responsible for site-wide controls (traffic management, emergency response)
- Communication: How risk information is shared among all duty holders
When Specialist Assessment Is Required
Engage competent specialists for:
Scientific Measurement:
- Noise exposure monitoring to determine if exposure exceeds limits
- Air monitoring for hazardous substances (silica, welding fumes, confined space atmospheres)
- Vibration exposure assessment
Structural and Engineering Analysis:
- Structural integrity during demolition or excavation near existing buildings
- Crane lift plans for complex or critical lifts
- Temporary works design (propping, shoring, scaffolding for non-standard applications)
Health Assessments:
- Health monitoring programs for workers exposed to specific substances (silica, lead, asbestos)
- Exposure assessments for substances without established exposure standards
Psychosocial Risk Assessment: Specialist organizational psychologists can assess complex psychosocial risks using validated tools and methods.
Summary
Risk assessment determines:
- How harm could occur by analyzing chains of events
- How severe the harm could be considering the type of harm, number of people exposed, and potential for cascading failures
- How likely harm is to occur based on exposure frequency, proximity, existing controls, and human factors
- The overall risk level combining severity and likelihood to prioritize control actions
Once risks are assessed, proceed to Step 3 to select and implement controls following the hierarchy of control measures.