A workplace incident investigation is a structured look at what happened and, more importantly, why, so that you can fix the cause and stop it happening again. The steps are: make the area safe, notify if required, record the scene, gather facts and statements, find the causes, fix them, and check the fixes worked. It isn’t about finding someone to blame. This guide walks through each step with a 5 whys example and a witness statement checklist.
Do you have to investigate incidents in Queensland?
The Work Health and Safety Act 2011 (Qld) and the Work Health and Safety Regulation 2011 (Qld) don’t set out a step-by-step investigation process for employers generally. (Most of the Act’s references to investigation are about the regulator and inspectors, and a few specific areas, such as major hazard facilities and sexual harassment reporting procedures, have their own requirements.) But your duties lead you there in practice:
- A person conducting a business or undertaking (PCBU) must ensure, so far as is reasonably practicable, the health and safety of its workers and other people (section 19 of the WHS Act), and must eliminate risks so far as is reasonably practicable or, if that isn’t possible, minimise them (section 17 of the WHS Act).
- A duty holder must review and, as necessary, revise control measures when they don’t control the risk they were meant to control. The Regulation gives “a notifiable incident occurs because of the risk” as an example (section 38(2)(a) of the WHS Regulation). You can’t review a control properly without knowing why it failed.
- Officers must exercise due diligence, which includes taking reasonable steps to make sure the business has processes for receiving and considering information about incidents, hazards and risks and responding to it in a timely way (section 27(5)(d) of the WHS Act).
- The approved How to Manage Work Health and Safety Risks Code of Practice 2021 (Qld) says that if someone has been harmed doing a task, a hazard exists that could hurt someone else, and these incidents need to be investigated to find the hazard that caused the injury or illness. A code of practice is guidance rather than law in itself, but a business must either follow an approved code or manage the risk in a way that gives an equivalent or higher standard of health and safety (section 26A of the WHS Act), and a court can rely on the code when deciding what is reasonably practicable (section 275 of the WHS Act).
Step 0: make safe, help the injured and check if it is notifiable
Before you investigate, look after people and make the area safe. Then decide whether it is a notifiable incident: a death, a serious injury or illness, or a dangerous incident (sections 35 to 37 of the WHS Act). If it is, the business must make sure the regulator is notified immediately after becoming aware of it, by the fastest possible means (section 38), and the person with management or control of the workplace must ensure, so far as is reasonably practicable, that the site (including any plant, substance, structure or thing associated with the incident) is not disturbed until an inspector arrives or any earlier time an inspector directs (section 39). Section 39 doesn’t stop you from helping an injured person, removing a deceased person, doing what is essential to make the site safe or minimise the risk of a further notifiable incident, doing something associated with a police investigation, or doing something the inspector or regulator has permitted. See our guide to notifiable incidents in Queensland for the details. Taking photos and notes without moving anything generally doesn’t disturb the site, but follow any direction from an inspector.
The investigation in eight steps
These steps are good practice, not a legal procedure. The WHS Act and Regulation don’t require this sequence.
- Start promptly. Memories fade and scenes change. Name one person to lead and, where possible, include someone who wasn’t involved and someone who knows the task.
- Record the scene. Photos, sketches, measurements, the equipment, the weather, lighting, the surface and what people were wearing. Note what has already been moved and by whom.
- Collect documents. Risk assessments, SWMS or JSA for the task, training and licence records, maintenance and inspection records, pre-start checks, rosters and earlier reports of similar events.
- Take witness statements. See the checklist below.
- Build a timeline. What happened, in order, from the start of the shift or task to the incident and what was done afterwards. Mark what is confirmed and what is assumed.
- Find the causes. Use a method such as 5 whys (below). Look for what was missing or didn’t work, not who made a mistake.
- Choose corrective actions. Pick the most effective controls you can. The hierarchy of control puts eliminating the hazard first, then substituting it, isolating people from it or using engineering controls, then administrative controls, and personal protective equipment last (sections 35 and 36 of the WHS Regulation). Assign each action to a named person with a date.
- Consult, close out and review. Tell workers what was found and what is changing. The Act requires you to consult workers, so far as is reasonably practicable, when identifying hazards and assessing risks and when making decisions about ways to eliminate or minimise them (sections 47 and 49 of the WHS Act). Then check the actions were done and worked, and review and, as necessary, revise the control measures (section 38 of the WHS Regulation), along with any risk assessment, SWMS or procedure that records them.
5 whys: a worked example
5 whys means asking “why?” repeatedly until you reach something you can fix. Five is a rule of thumb, not a requirement, and a problem can have more than one cause, so follow each branch. This example is an illustration written for this guide.
| Question | Answer |
|---|---|
| Incident | A worker slipped near the wash bay and injured a wrist |
| 1. Why did the worker slip? | The concrete was wet and slippery |
| 2. Why was it wet? | Hose water ran across the walkway instead of into the drain |
| 3. Why didn’t it run into the drain? | The drain was blocked with sediment |
| 4. Why was it blocked? | Nobody cleaned it; it was not on any inspection or cleaning list |
| 5. Why wasn’t it on a list? | The wash bay was added after the original inspection list was written and no one was assigned to inspect it |
The cause is a gap in the system (no inspection routine and no owner), not a careless worker. Corrective actions could be: clear the drain and fix the fall of the slab (engineering), add the wash bay to the weekly inspection and name an owner (administrative), and review the housekeeping procedure. Telling the worker to “be more careful” would be the weakest option on its own.
Witness statement checklist
A witness statement for your own investigation is a workplace record, not a police statement or statutory declaration, and the law doesn’t set a form for it. Keep it accurate and factual, because an inspector can require documents to be produced (section 171 of the WHS Act) and records may be relied on later. A good one:
- is in the person’s own words, signed and dated, with the time and place it was taken
- says who the person is, their role and where they were when it happened
- describes what they saw, heard and did, in order, and separates facts from opinions or guesses
- is taken as soon as practical, ideally from each witness separately, without leading questions
- notes who else was present, and any photos, documents or equipment they know about
Be considerate. Offer the person a support person if they want one, and don’t pressure anyone to sign or change what they said. If the regulator or police become involved, find out what they need and get advice if you are unsure.
Common mistakes
- Stopping at “human error”. People make mistakes, but ask why the system allowed one to cause harm.
- Relying on retraining alone. Training is an administrative control. Look for something higher up the hierarchy first.
- Ignoring near misses. They show the same failures without the injury. See what a near miss is.
- Not checking the fix. An action that is written down but not done, or not effective, leaves the risk where it was.
- Not keeping records. You must keep a record of each notifiable incident for at least 5 years from the day notice is given to the regulator (section 38(7) of the WHS Act). Keeping the investigation notes with it is sensible. For other incidents, keep what you need to show what you found and fixed. See reporting and recording workplace injuries.
Forms and templates
Use the free incident report form template to capture the first facts (our guide to writing an incident report shows what to include), and log each event in the free incident register template (see also our incident register guide). Update your controls on the free risk assessment template, and set out who does what in the incident management policy and procedure template. To rate the risk before and after, see how to use a 5×5 risk matrix.
This guide is general information, not legal advice. Check the current law or talk to Workplace Health and Safety Queensland for your situation.
Templates for this job
Ready-to-edit Word and Excel templates for Queensland workplaces.
