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Nursing and midwifery staff may be at risk of occupational exposure to Entonox. We’ve broken down everything RCN reps and members need to know and provided links to resources and useful information.

What is Entonox? 

Entonox is the trade name for “gas and air” or “laughing gas”, which is used as a form of pain relief.  

It’s comprised of oxygen and nitrous oxide and is commonly used in areas, such as acute trauma, labour wards, community settings (home births), as well as during wound dressings and suturing.  

Entonox is administered through a mouthpiece: when the patient inhales, a valve opens and allows the gas to be released – however, vapours can also be released into the room. 

What are the risks? 

Members might inhale Entonox in what’s known as occupational exposure, when working with a patient who is using it to manage pain and the room is poorly ventilated. 

This can lead to adverse health effects including a decrease in mental performance, audio-visual ability and manual dexterity. 

Members might even experience addiction to Entonox, and over time, the gas can prevent the body from absorbing vitamin B12, leading to anaemia and other neurological effects. 

Bowel distension, ear damage and a reduction in fertility have also been noted as symptoms.

What can employers do about it? 

Employers have a legal duty to assess the risk of staff being exposed to Entonox, including during pregnancy and breastfeeding.

The Health and Safety Executive has set a workplace exposure limit (WEL) for concentrations of Entonox in the air and this should not be exceeded.

Examples of suitable control measures may include improving ventilation or the use of gas scavenger units.  

In addition, employers should ensure staff are suitably trained and that control measures are monitored to check their effectiveness.

What can safety reps do?  

RCN representatives can ask their employers to provide assurances that Entonox exposure is being managed and kept as low as possible.  

NHS England has produced guidance, which reps can bring to their employers, that outline in greater detail what control measures might entail.  

How do I raise concerns?  

Members can contact RCN Direct if they wish to talk further about their exposure concerns. Our employment relations team can also step in and provide information and advice. Our health and wellbeing team can be emailed at

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