COSHH by Area

COSHH in the Bar and Cellar

Cellar Gas, Line Cleaner, and the COSHH Risks Behind the Bar

The bar and cellar carry two COSHH risks that are easy to underestimate. The first is carbon dioxide and mixed cellar gas, which can build up in a poorly ventilated cellar and cause collapse with very little warning. The second is beer line cleaner, a corrosive caustic that bar staff handle routinely and that has caused serious injuries when it has been mistaken for a drink or splashed in the eyes. Add glasswash detergent and rinse aid and the bar becomes an area that needs a proper COSHH assessment rather than the afterthought it often gets. This guide covers the substances behind the bar and in the cellar and the controls that keep bar staff safe.

Check a cellar gas safety data sheet See COSHH features

Key takeaways

Carbon dioxide and mixed cellar gas can accumulate in a cellar and cause collapse without warning; treat the cellar as a confined space.

Fit a CO2 alarm, store cylinders upright and ventilated, and train staff never to re-enter a cellar after an alarm.

Beer line cleaner is a corrosive caustic and has caused serious injuries when mistaken for a drink.

Never store line cleaner in a glass or jug, always label it, and wear gloves and eye protection when cleaning lines.

Glasswash detergent and rinse aid are corrosive; keep them labelled, wear gloves when changing containers, and never mix them.

Carbon Dioxide and Cellar Gas Safety

Carbon dioxide is used to dispense beer and soft drinks, often as pure CO2 or as a mixed gas with nitrogen. It is heavier than air, colourless, and odourless, so a leak from a cylinder, a coupler, or a burst line can accumulate at floor level in a cellar without anyone noticing. At raised concentrations it causes headaches, dizziness, and rapid breathing, and at high concentrations it can cause unconsciousness and death, sometimes before the person realises anything is wrong. The controls are specific: a CO2 gas alarm fitted in the cellar, cylinders chained upright and stored in a ventilated space, staff trained never to enter a cellar where the alarm has sounded, and a clear rule that anyone who feels unwell leaves immediately and raises the alarm rather than going back in to help. The cellar is effectively a confined space when gas can build up, and it should be assessed as one.

Beer Line Cleaner Is Corrosive

Beer line cleaner is a strong caustic, usually sodium hydroxide based, and it is one of the most hazardous substances behind the bar precisely because it is handled so casually. It is highly corrosive to skin and eyes and extremely dangerous if swallowed. The recurring serious incidents involve line cleaner being left in a jug or an unlabelled glass and then drunk by a member of staff or a customer, and splashes to the eyes during line cleaning. Controls start with substitution where a lower-hazard cleaner does the job, then move to clear labelling of any container holding cleaner, never using drinking vessels, wearing gloves and eye protection during the clean, flushing lines thoroughly afterwards, and a strict rule that line cleaning happens when the bar is closed or quiet and the lines are clearly marked as out of use. Bar staff must know the first aid response: rinse skin and eyes with plenty of water and seek medical help.

Glasswash Chemicals and Bar Cleaning

The glasswasher uses a corrosive, high-pH detergent and an acidic rinse aid, usually drawn from bulk containers under the bar. The risks are splashes when changing or connecting containers and contact with residue. General bar cleaning brings sanitisers and surface cleaners into daily use. The controls are familiar but often neglected behind a busy bar: keep detergent and rinse aid in their original labelled containers, wear gloves when changing them, never mix the two, and store all chemicals away from glassware and garnishes. As with the kitchen, the bar COSHH assessment should sit where staff work, behind the bar and in the cellar, so that the emergency advice for a CO2 alarm or a line cleaner splash is to hand at the moment it is needed rather than locked in the manager office.

What to do next

Fit and test a CO2 alarm in the cellar

Install a carbon dioxide alarm, keep it tested, and make the rule clear that nobody enters when it has sounded until the cellar is confirmed safe.

Label every container of line cleaner

Never decant line cleaner into a glass or jug. Label the container clearly and mark lines as out of use during cleaning.

Brief bar staff on the cellar and line cleaning controls

Cover gas safety, line cleaning protective equipment, and the first aid response for a corrosive splash, and record the training.

Common mistakes to avoid

Mistake

Leaving beer line cleaner in a glass or jug

Instead

This is the cause of the most serious line cleaner incidents. Keep cleaner only in a labelled container, never in any drinking vessel, and flush lines thoroughly after cleaning.

Mistake

Treating the cellar as an ordinary store room

Instead

A cellar where CO2 can build up is effectively a confined space. It needs a gas alarm, ventilation, and a clear rule about not entering after an alarm sounds.

Frequently asked questions

Is carbon dioxide a COSHH hazard in a pub cellar?

Yes. CO2 used for dispense can leak and accumulate in a cellar, where it is heavier than air and hard to detect. It must be assessed under COSHH, with a cellar gas alarm, ventilation, and trained staff among the controls.

Why is beer line cleaner so dangerous?

It is a strong corrosive caustic, usually sodium hydroxide based. It burns skin and eyes and is very dangerous if swallowed. Serious injuries have happened when it was left in a glass or jug and drunk by mistake.

Do I need a CO2 alarm in my cellar?

Where CO2 cylinders are kept or used in a cellar, a fixed gas alarm is the recognised control to warn staff before levels become dangerous. It should be part of your COSHH controls along with ventilation and training.

What protective equipment do bar staff need for line cleaning?

Chemical-resistant gloves and eye protection at minimum, because line cleaner is corrosive. Staff should also know to rinse skin or eyes with plenty of water after any contact and seek medical advice.

Hazardous Substances in Hospitality