RIDDOR dangerous occurrences: the incidents that count even when nobody's hurt

Most conversations about RIDDOR focus on injuries, because an injury is the obvious trigger for a report. But one of RIDDOR's four reportable categories doesn't require anyone to have been hurt at all — dangerous occurrences are specified events that had clear potential to cause serious harm, reportable in their own right regardless of outcome.

What actually counts as a dangerous occurrence

The category covers a defined list of event types rather than a general sense of what sounds dangerous — things like the collapse, overturning or failure of load-bearing parts of lifts and lifting equipment, the collapse or partial collapse of scaffolding of a certain height or over a certain load, and uncontrolled releases of certain substances. The exact list is specific and worth checking directly against current HSE guidance, because not every alarming-looking event on site meets the defined threshold, and some events that don't look dramatic from the outside do.

Why this category exists separately from injury reporting

The logic is straightforward once you see it: waiting for an injury to happen before HSE gets visibility of a genuinely serious equipment or structural failure means the reporting system only learns about a hazard after someone's already been hurt by it. A scaffold that partially collapses overnight, with nobody underneath it at the time, is exactly as much evidence of a structural failure as one that collapses onto someone — the only difference is luck about who was standing where at that particular moment.

A worked example

A tower crane's load block fails during a lift, dropping the load from height. Nobody is beneath it, and no injury results. Under a narrow, injury-focused reading of RIDDOR, it's tempting to treat this as a near miss worth an internal note and nothing more. In fact, the failure of load-bearing parts of lifting equipment is squarely the kind of event the dangerous occurrence category exists to catch — and this connects directly to the thorough examination requirements under LOLER: a dangerous occurrence involving lifting equipment is often the point where an examination or maintenance gap becomes visible, sometimes for the first time.

The judgement call in the middle

The clearest cases — a major structural collapse, an obvious equipment failure — rarely cause genuine confusion about whether to report. The harder judgement sits with events that are serious but don't obviously match one of the specified categories, or that are borderline in scale, such as a partial scaffold failure that doesn't meet the specified height or load threshold. This is precisely where it's worth having whoever handles incident reporting check the specific event against current HSE guidance directly, rather than defaulting to either extreme of over-reporting everything that looked alarming or under-reporting on the assumption that nobody being hurt settles the question.

Recording it even when it isn't reportable

Not every alarming event meets the dangerous occurrence threshold, but that doesn't mean it isn't worth recording internally as a near miss. The distinction between reportable and merely worth-recording matters for compliance, but from a genuine safety-management perspective, both are telling you the same thing: a hazard exists on your site that came close to causing serious harm, and it's worth investigating regardless of which side of a reporting threshold it happens to fall on.

Common mistakes

• –Treating dangerous occurrences as only relevant when they happen to result in an injury
• –Assuming an alarming-looking event is automatically reportable without checking it against the specific defined categories
• –Under-reporting because nobody was actually hurt, when the category exists precisely to catch harm-free events
• –Not connecting a dangerous occurrence involving plant or lifting equipment back to its maintenance and examination history
• –Treating a near-threshold event as not worth recording internally just because it doesn't meet the formal reportable definition
• –Relying on memory of past categorisations rather than checking the current specified list directly

This post is a starting orientation, not the statutory list itself — check current HSE guidance directly before relying on any specific classification.