How to do a COSHH assessment— six steps, in the order the work happens.
Who can do one
Someone competent: they understand the work, they can read a safety data sheet, and they know what a control actually achieves. Competence is knowledge and experience, not a certificate. Whoever signs it is accountable for it.
The duty to have one sits with the employer — never with the person holding the tin.
The six steps
Start at the sheet. Finish at the briefing.
- 01
Get the safety data sheet, and check it is current
The supplier must give you one. Find the revision date on page one and compare it with what you last assessed. An assessment written against a superseded sheet is evidence of nothing.
The judgementIs this the sheet for the tin actually in the store?
- 02
Describe the job, not the product
What is being done, by whom, how much, how often and where. Indoors, outdoors, confined, occupied — the same substance is a different risk in each.
The judgementIf two jobs use it differently, that is two assessments.
- 03
Work out how people could be exposed
Breathing it in, skin, eyes, swallowing. Include the people nearby who are not doing the work — the resident in the next room, the trade following you.
The judgementOnly record the routes that apply to this job. Everything recorded has to be dealt with.
- 04
Decide the controls, best first
Stop using it. Swap it for something safer. Engineer it out with extraction, enclosure or ventilation. Change the way of working. Protective equipment comes last, because it only protects when it is worn correctly every time.
The judgementReaching for gloves and a mask first is the most common failing in a rejected assessment.
- 05
Prove each route is covered
For every exposure route you recorded, say which control deals with it. This is the step that turns a list of good intentions into an assessment.
The judgementIf nothing covers a route, either add a control or the route should not be there.
- 06
Issue it, brief it, and set the review
Someone competent signs it and is accountable for it. The people doing the work have to be told what it says before they start. Then it gets reviewed — when anything changes, and at a planned interval.
The judgementA signed assessment nobody has read is paperwork, not control.
Two things worth knowing
Exposure limits, and the substances with no sheet.
Neither of these comes from a supplier. Both still need the same six steps, and both are where an assessment most often turns out to be missing entirely.
Workplace exposure limits
Some substances have a legal airborne limit published by HSE in EH40. If one applies, exposure has to be kept below it, and for the worst substances as far below as is reasonably practicable.
Dust and fume the work creates
Silica from cutting, wood dust, welding fume and exhaust have no supplier safety data sheet — nobody sold them to you. They still need assessing, and they are among the most harmful things on a site. Start from HSE’s guidance for the specific hazard.
Need the paper?
There is a blank template on this site, laid out in the order of these six steps.
The way through
Start from the sheet the supplier already gave you.
You have just read the six steps. Five of them are the tool; the sixth — the judgement about controls — stays yours, which is the way round it should be.
- 01
Upload the supplier safety data sheet.
- 02
Check the facts it read, and correct anything wrong.
- 03
Say what the job is and who is exposed.
- 04
Choose the controls, and confirm what covers each route.
- 05
Issue it. Send the link.