Three columns
| Step | Hazard | Control |
|---|---|---|
| The step as the work is actually done | What can go wrong at that step | A control chosen by the hierarchy |
The rule for writing steps
Steps should be neither too coarse nor too fine. “Take the pump out of service” is too coarse to be one step; “put the glove on your right hand” is too fine. A good JSA usually lands between 8 and 15 steps. Steps are written by observation: watching the work, asking the person doing it.
Why the worker must be at the table
The written procedure and the practice on site are usually not the same — and the gap is exactly where the hazard lives. A JSA prepared without that person analyses work that is not actually done, and once it reaches the field nobody follows it.
When it is used
- to establish a standard safe method for repeated hazardous tasks,
- when moving to a new task or new equipment,
- after an incident or near miss, to revisit the steps of that task,
- as an annex to a permit to work: the steps and controls of the permitted task.
Relation to the risk assessment
A JSA does not replace the general risk assessment; it deepens it at task level. The assessment says “this unit has these hazards”, the JSA says “doing this task, at this step, this happens”. They feed each other: a hazard found in a JSA goes into the assessment.