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Staff exposure to nitrous oxide

Why monitor exposure?

The Control of Substances Hazardous to Health (COSHH) Regulations require that, for every exposure to substances hazardous to health, the following should be carried out:

• Assessment of the risk
• Methods of achieving control of the risk
• Personal monitoring for exposure to substances hazardous to health

The volatile anaesthetic agents are potentially harmful to staff and are subject to the COSHH Regulations. The employer has a legal duty to ensure that exposure to these substances is kept to a minimum.

Who is at risk?

Staff working in areas where nitrous oxide and oxygen/nitrous oxide mixtures (e.g. Entonox™) are used can be exposed to nitrous oxide. The principal risk groups are:

• Midwives
• Surgeons
• Anaesthetists
• Recovery nurses
• Surgical staff

How can we help?

Quality Control West Midlands provides a number of services to enable you to meet your legal obligations under the COSHH Regulations:

• Personal exposure to nitrous oxide monitoring of staff
• Room air sampling for volatile anaesthetic agents
• Testing of control measures
• Room ventilation (supply/extract rates)
• Room overpressures
• Anaesthetic gas scavenging systems

Sampling devices

We use compact, lightweight monitors, weighing 230 grams, that measure levels of nitrous oxide in the air. The device is worn by an individual to assess exposure levels, or located within a room to monitor background. The levels are logged within the units at pre-defined intervals and the data is then downloaded. In the detailed report you receive you will then have exposure levels time referenced.

Occupational exposure limits

The Health and Safety Executive have eight principles for occupational exposure limits (OELs):

• Design and operate processes and  activities to minimise emission, release and spread of substances hazardous to health
• Take into account all relevant routes of exposure - inhalation, skin absorption and ingestion - when developing control measures
• Control exposure by measures that  are proportionate to the health risk
• Choose the most effective and reliable control options which minimise the escape and spread of substances hazardous to health
• Where adequate control of exposure cannot be achieved by other means, provide, in combination with other control measures, suitable personal protective equipment
• Check and review regularly all elements of control measures for  their continuing effectiveness ]
• Inform and train all employees on the hazards and risks from the substances with which they work and the use of control measures developed to minimise the risks
• Ensure that the introduction of control measures does not increase the overall risk to health and safety

The OELs for nitrous oxide over an eight-hour time weighted average is 100ppm. In addition to these we can also monitor for volatile anaesthetic agents.