Vapour intrusion: Technical practice note

As a leading protector of human health and the environment, the EPA has developed this technical practice note for consultants and site auditors who assess chronic health risks from exposure to vapours from volatile chemicals in soil or groundwater.

Soil or groundwater that is contaminated with chemicals which are volatile, for example, petroleum hydrocarbons, can be a source of vapours which can move into buildings, confined spaces or excavations on a site. The potential risk to human health from vapour intrusion should be evaluated as part of assessments of sites with a vapour risk. This evaluation is particularly relevant to buildings with a slab-on-ground construction or basements where air flow is reduced and exposure may be a higher risk. 

This practice note only addresses chronic health risks. If you suspect an acute or explosive risk, take appropriate precautions and contact emergency services immediately.

Topics include

  • planning the vapour assessment
  • sampling methods
  • interpreting and modelling scenarios
  • assessing health risks

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