Workplace health and safety investigation response workflow
A WHS investigation can escalate from notifiable incident to Category 1 prosecution quickly. The PCBU and officers must comply with s 155 notices while preserving privilege and avoiding inadvertent admissions. A disciplined internal response in the first 30 days often determines whether the matter ends in an improvement notice or an indictment.
This is an 8-step workflow for responding to a SafeWork or equivalent regulator investigation under the Work Health and Safety Act 2011 (NSW) and the harmonised model WHS laws. It runs from notifiable incident through investigation response to enforceable undertaking or prosecution.
Before you start
- Signed costs agreement and conflict check across PCBU and officers
- Incident notification records and any SafeWork notices issued
- Safe work method statements, risk assessments, and training records
- Privilege protocol across the investigation team
The workflow
Preserve the scene and notify
Preserve the scene for regulator inspection, notify SafeWork of a notifiable incident within the statutory timeframe, and keep a privileged incident log.
Engage internal investigation under privilege
Engage an internal investigation, ideally under privilege instructed by legal, covering root cause, systems, and culture. Separate factual statements from opinion.
Respond to s 155 notices to produce
Assess each notice under s 155 for scope and privilege. Produce documents on time; claim privilege over privileged material; object where scope is excessive.
Manage interviews under s 155
Prepare workers and officers for s 155 interviews — right to legal representation, privilege against self-incrimination in respect of natural persons, and the use immunity under s 172.
Assess exposure across duty-holders
Map exposure across the PCBU (s 19), officers (s 27), workers (s 28), and principal contractor. Identify Category 1, 2, or 3 risk and industrial manslaughter exposure.
Remediate and document improvements
Implement remediation — updated SWMS, training, equipment, supervision — and document each step. This evidence supports any enforceable undertaking proposal or sentencing submission.
Consider enforceable undertaking proposal
Where the regulator is considering prosecution, prepare a Work Health and Safety Undertaking proposal under s 216 — remediation, industry benefit, and worker benefit components.
Defend or plead to prosecution
If prosecuted, advise on defence (reasonably practicable steps) or plea. Prepare sentencing submissions addressing cooperation, remediation, and contrition consistent with current authorities.
What you will have at the end
Either an improvement or prohibition notice, a closed investigation, an accepted enforceable undertaking, or a prosecution outcome — with documented remediation that supports the commercial and regulatory future of the PCBU.
Common issues
- First-hour statements to regulators given without legal advice
- Privilege waived by circulating internal investigation report widely
- Officer due diligence (s 27) not separately analysed from PCBU duty
- Enforceable undertaking proposal submitted too late to influence prosecution
- Industrial manslaughter exposure missed where a fatality has occurred
Run this workflow on a real matter
Quillio drafts the s 155 response, the privileged investigation framework, and the enforceable undertaking proposal. See /practice-areas/employment-lawyers or start a free trial at /free-trial.
General guide only — not legal advice. WHS investigations have criminal consequences for officers and the PCBU; obtain specialist advice immediately.
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