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What is LEV?

See: UCLs Standard - Local exhaust ventilation for the statutory arrangements in place for the examination and testing of LEV including the allocation of responsibilities.

Local Exhaust Ventilation – LEV – is a ventilation system that takes hazardous substances including gases, vapour, fume, mist, dust and other aerosolised particles out of the air so that they can’t be breathed in.

LEV can either extract to an external location or recycle air, but in all cases it has the aim of removing contaminated air and if recycled back into a room, filtering to prevent people breathing in hazardous substances.

Common LEV includes Fume Cupboards, Microbiological Safety Cabinets, Capture hoods and Gas Safety Cabinets.

Why we use it & what can go wrong!

LEV helps prevent users from inhaling hazardous substances, but it can only provide protection if selected, installed, used and maintained correctly.

safety cabinet

LEV is classed an engineering control and is a good measure to use, however it should not be used alone. Always consider using control measures in combination, for example:

                • Avoid a hazard or substitute it with something less harmful (less concentrated chemical, different material etc.)
                • Limit frequency of use and duration of exposure to hazardous substances
                • Use procedural controls (methods, operating procedures, work instructions)
                • Wear appropriate personal protective equipment (PPE)


Remember - always read your local risk assessments – they will identify hazards in your work area, the controls you need to follow including LEV. If you use LEV but it is not mentioned on a risk assessment, make sure the document is updated.

Every year, thousands of people in the UK develop occupational diseases from breathing in dusts, fumes or other airborne contaminants at work. Make sure you’re not one of them!



The law


Clearing the air: A simple guide to buying and using local exhaust ventilation (LEV)


The Control of Substances Hazardous to Health Regulations 2002

Frequently asked questions



Time to clear the air! - A workers’ pocket guide to local exhaust ventilation (LEV)

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