Incident Investigation Process

Incident investigation identifies the root causes of accidents, near misses, and dangerous occurrences to prevent recurrence.
The goal is to find out what happened and why — not to assign blame to individuals involved in the incident.
Investigation must begin as soon as possible after the incident, while evidence is fresh and the scene is undisturbed.
The scene must be preserved until the investigation team has completed evidence collection, photographs, and measurements.
Witness statements should be taken individually, as soon as practicable, and recorded in writing with the witness's own words.
Root cause analysis methods such as 5 Whys, fishbone diagrams, and fault trees help identify underlying systemic failures.
Most incidents have multiple contributing factors — focusing on a single cause misses opportunities to prevent future events.
Corrective actions must be specific, measurable, assigned to a responsible person, and given a completion deadline.
Investigation findings and lessons learned must be communicated to the wider workforce through toolbox talks and safety alerts.
A follow-up review must confirm all corrective actions have been implemented and are effective in preventing recurrence.

Prevent recurrence	Investigation finds the root cause — fixing it prevents the same incident from happening again to another worker.
Not about blame	A blame culture stops people reporting and cooperating — effective investigation seeks understanding, not punishment.
Systemic improvement	Most incidents result from system failures, not individual errors — investigation improves the systems that protect everyone.

Do

Don't

Begin the investigation promptly while evidence is fresh and accessible.
Preserve the incident scene until all evidence is collected and documented.
Take individual witness statements in private, recording their own words accurately.
Use structured root cause analysis methods to go beyond the immediate trigger.
Identify all contributing factors, not just the single most obvious cause.
Define corrective actions that are specific, assigned, and time-bound.
Communicate findings to the workforce through toolbox talks and safety alerts.
Follow up to confirm corrective actions are implemented and working effectively.
Keep investigation records as permanent project documentation for future reference.
Treat the investigation as a learning opportunity, not a blame exercise.

DON'T delay the investigation — evidence degrades and memories fade rapidly.
DON'T disturb the incident scene before the investigation team has collected evidence.
DON'T take group witness statements — speak to each person individually and privately.
DON'T stop at the first obvious cause — dig deeper to find the root cause.
DON'T attribute the incident to a single factor when multiple causes contributed.
DON'T set vague corrective actions — they must be specific with a named owner and deadline.
DON'T keep investigation findings to yourself — share lessons to protect the whole workforce.
DON'T close the investigation until corrective actions are confirmed implemented and effective.
DON'T lose investigation records — they are essential for legal defence and future learning.
DON'T use the investigation to punish individuals — focus on fixing the system.

See also: Accident and Incident Reporting (RIDDOR) | Near Miss Reporting and Learning

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Toolbox Talk Record