Fall Investigation and the Supervisor's Preferred Conclusion
You are the lead investigator for a serious incident at a 120-worker construction site. A carpenter fell 3.2 m from a scaffold when his lanyard was not attached. He has a fractured wrist and is in hospital. The site supervisor says the worker 'ignored training' and wants the report to conclude 'worker error' by tomorrow. Three witnesses give different accounts: one says the anchor point was missing; another says the worker was told to work without it; the third says he saw the worker unclip to move. The scaffold tag is missing. The regulator must be notified within 24 hours. The worker is also the union safety rep. A camera at the gate may have footage, but the site manager says it is 'probably not working.'
1. What evidence do you secure in the first 24 hours, and how do you avoid destroying or contaminating it?
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Secure people, scene, and records in parallel. First, ensure the injured worker is treated and that the scene is barricaded; do not let the scaffold be altered except to make it safe. Photograph the scaffold, lanyard, harness, anchor points, tag location, and ground conditions before anything is moved. Take the lanyard, harness, and any tag into custody with a chain-of-custody log. Interview witnesses separately and record their exact words, not a summary. Request the gate camera footage in writing immediately and ask for preservation, even if the manager says it is probably not working; test it rather than accept the claim. Collect training records, scaffold inspection records, rescue plan, and the worker's tasks for that shift. Notify the regulator within the required time, facts only. Avoid group interviews and avoid asking the supervisor to collect statements from their own crew.
2. How do you handle the supervisor's requested conclusion and the conflict of interest created by the worker's union role?
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I would tell the supervisor that the conclusion will follow the evidence, not a preferred outcome. The supervisor's request is a bias risk, especially because their own supervision and scaffold controls are in scope. I would separate the investigation from any disciplinary process and keep the supervisor out of evidence collection for their area. The worker's union safety rep role increases the risk of perceived reprisal, so I would document that the investigation treats him as an injured worker and witness, not as an adversary. I would interview the supervisor as a witness, not as a co-investigator. If the supervisor presses for 'worker error,' I would record the request and my response. The conflict is not solved by excluding the supervisor; it is managed by transparency, independent review, and evidence-based findings.
3. What does a defensible report conclude when evidence is incomplete? How do you word findings and recommendations?
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A defensible report separates findings of fact, causal analysis, and recommendations. It should not declare 'worker error' when anchor-point availability, instruction, and scaffold tagging are disputed. It can state: the worker fell while the lanyard was not attached; the anchor point was reported missing by one witness and disputed by another; the scaffold tag was absent; and supervision instructions are inconsistent. Cause should be framed as likely contributing factors, such as missing anchor point, unclear tie-off instruction, and failed scaffold inspection, with confidence levels. Recommendations should be systemic: verify anchor points before work, tag and inspect scaffolds, require tie-off plans, train supervisors on rescue and stop-work, and protect witnesses from reprisal. Include limitations and next steps, such as camera footage review and regulator findings. The report should be defensible to a regulator, a court, and the worker, not just to the supervisor.