A health risk assessment of working in hypoxic atmospheres

Hypoxic atmospheres - those in which the ambient oxygen level is lower than normal – may be specifically generated in some workplaces, particularly for fire prevention. Such atmospheres potentially present a health risk to workers who are required to enter the hypoxic space. This report reviews the impact of hypoxia on human physiology, behaviour, and cognitive function, in order to provide information about the potential occupational health risks arising from working in hypoxic atmospheres.

The available evidence suggests that hypoxic environments in which the levels of oxygen are greater than 15% but below 21%, are safe for most healthy, fit individuals. However, prior to entry into such environments, risk assessments should be performed to cover: the working environment; the work and tasks undertaken; and the worker. Occupational health assessments should be in place for all workers who have a potential requirement to enter these atmospheres. Careful consideration should be given to: workers carrying out tasks that require higher levels of physical activity; and pregnant workers.

For hypoxic working environments between 12% and 15% oxygen, there is a lack of evidence-based or expert consensus-led guidance that addresses medical conditions and their severity. There is therefore an insufficient evidence-base to provide guidelines for safe working in hypoxic environments between 12-15% oxygen, other than relating to the use of supplemental oxygen.

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Updated 2021-04-16