COSHH Assessments

COSHH Risk Rating Explained

How to Rate Risk in a COSHH Assessment Without Overcomplicating It

Many COSHH templates ask you to give each substance a risk rating, often a number from a likelihood-times-severity grid. Used well, a rating helps you prioritise the substances that need the most attention. Used badly, it becomes a box-ticking exercise where every chemical ends up marked medium and nothing is actually controlled. This article explains how COSHH risk rating works, how to judge likelihood and severity in a kitchen or bar, and how to keep the rating useful rather than ornamental.

Key takeaways

A risk rating helps you prioritise substances; it is not the assessment itself.

Rate likelihood and severity with your current controls in place, judging the use rather than the chemical alone.

A simple low, medium, high judgement with a reason beats a precise-looking number nobody can justify.

The substances that usually rate high in hospitality are corrosive cleaners, strong descalers, drain unblockers, and cellar gas.

If the rating does not change what you do, it is not doing its job.

What a Risk Rating Is For

A risk rating exists to help you decide where to focus. It is the product of how likely harm is and how serious that harm would be, judged with your current controls in place. A corrosive oven cleaner sprayed neat is severe if it contacts skin or eyes and reasonably likely without good controls, so it rates high and deserves strong controls and clear training. A diluted general sanitiser wiped on a surface with gloves available is low on both counts. The rating is not the end of the assessment; it is a way of ranking your substances so the high-risk ones get the attention they need rather than being lost in a long flat list.

Judging Likelihood and Severity in Hospitality

Likelihood depends on how the substance is used: neat or diluted, sprayed or wiped, in a confined space or a ventilated one, often or rarely, by trained staff or by anyone. Severity depends on the hazard classification and the route of exposure: a corrosive that can cause permanent eye damage is more severe than a mild irritant. In practice you do not need a complex matrix. A simple low, medium, high judgement for each substance, with a sentence explaining why, is more useful and more honest than a precise-looking number that nobody can justify. The substances that consistently rate high in hospitality are corrosive oven and grill cleaners, strong descalers, drain unblockers, and cellar gas in confined cellars.

Avoiding the Common Rating Traps

The first trap is rating every substance medium, which tells you nothing and controls nothing. Force yourself to separate the genuinely high-risk products from the low-risk majority. The second trap is rating the chemical rather than the use, so a product comes out high simply because its safety data sheet looks alarming, even though you use a tiny amount diluted and wiped. The third trap is letting the rating replace the controls: a number in a box is not a control. The rating should lead directly to a decision, namely that high-risk substances get substitution where possible, the strongest controls, and the clearest training, while low-risk ones get proportionate, lighter handling. If the rating does not change what you do, it is not earning its place.

What to do next

Separate the high-risk substances from the rest

Avoid rating everything medium. Identify the handful of genuinely high-risk products and give them the strongest controls.

Write one sentence justifying each rating

A short reason for each low, medium, or high rating keeps the judgement honest and helps an inspector follow your thinking.

Turn high ratings into action

For each high-risk substance, decide whether you can substitute it, then set the controls and training it needs.

Common mistakes to avoid

Mistake

Rating every chemical the same

Instead

A flat list of medium ratings hides the substances that actually need attention. Distinguish the high-risk products clearly.

Mistake

Rating the chemical instead of how you use it

Instead

A product with an alarming safety data sheet may be low risk in your hands if used in small, diluted amounts. Rate the real use.

Frequently asked questions

Do I have to give a COSHH risk rating?

The regulations do not require a specific numerical score. They require a suitable and sufficient assessment of risk. A rating is a helpful way to prioritise, but a clear low, medium, high judgement with reasons is enough.

How do I work out the risk rating for a chemical?

Judge how likely harm is, based on how the substance is used, and how severe it would be, based on the hazard and the route of exposure, with your current controls in place. Combine the two into a low, medium, or high rating and explain why.

Which hospitality chemicals are usually high risk?

Corrosive oven and grill cleaners, strong descalers, drain unblockers, and carbon dioxide in confined cellars are the substances that most often rate high because of their severity and the way they are used.

COSHH Assessments