In this module
Objectives covered: LO 2.9.1. By the end you will be able to:
- Use leading and lagging indicators to check that controls work.
- Investigate an incident and find root causes using the 5 Whys.
- Know when a hazard analysis must be reviewed.
9.1 Controls wear out
Guards get removed, ventilation fans fail, procedures drift, new workers arrive. Hazard analysis is not a one-time paper. You must check that controls are still in place and still working.
9.2 Leading and lagging indicators
| Lagging (after harm) | Leading (before harm) |
|---|---|
| Lost-time injuries (LTI), LTIFR | Inspections completed on time |
| Recordable injuries (TRIR) | Near misses reported |
| Occupational illness cases | Corrective actions closed on time |
| Property damage | JHAs reviewed, training completed, permit audits |
Lagging indicators tell you that you failed. Leading indicators tell you whether you are doing the things that prevent failure.
9.3 Incident investigation
- Make safe and give first aid.
- Preserve the scene and collect evidence: photos, statements, records.
- Find the facts: what happened, in order.
- Find the causes: immediate causes (unsafe act or condition), and root causes (system failures).
- Agree actions that fix the root causes, with owners and dates.
- Share the lessons across the company.
9.4 The 5 Whys
A worker's hand was cut by a fan blade.
- Why? The fan guard was missing.
- Why? It was removed for cleaning and not refitted.
- Why? The cleaner did not have the right screws to refit it.
- Why? Spare fasteners are not stocked, and nobody checks guards after cleaning.
- Why? The cleaning procedure has no guard-check step and no sign-off.
Root cause: the cleaning procedure. Blaming the worker would not stop it happening again; fixing the procedure would.
Look for the system failure, not someone to blame. A no-blame reporting culture brings more near misses to the surface.
9.5 When to review the hazard analysis
- After an incident or near miss.
- When there is a change: new equipment, chemical, process, layout or people.
- When new information appears, such as a new exposure limit or an industry accident.
- At a set interval, typically yearly (5 years for a PSM process hazard analysis).
- ISO 45001 clauses 9.1 (monitoring), 10.2 (incident and corrective action), 10.3 (continual improvement).
- OSHA 29 CFR 1904: recording and reporting of occupational injuries and illnesses.
- Bangladesh Labour Act 2006, Section 80: notice of accidents to the inspector (Department of Inspection for Factories and Establishments, DIFE).
A cement plant in Munshiganj had good LTI figures but rising near misses at its clinker conveyor. Instead of ignoring them, the safety committee used the 5 Whys on each one, found that guards were being removed to clear spillage, and installed spillage chutes and interlocked guards. The near misses stopped before anyone was hurt. Leading indicators gave the warning in time.
Learning Check
Answer these two questions to check your understanding. You can try again as many times as you like.