Vapor intrusion

Vapor intrusion (VI) is the process by which chemicals, usually volatile organic compounds (VOCs), in soil or groundwater migrate to indoor air above or around a contaminated site.

[1] The process of VI has been studied more recently in relation to its effects on humans and the environment, and is becoming more regulated by the United States Environmental Protection Agency (US EPA).

Preferential pathways, such as elevator shafts, pipes, and storm drains, act as an easy path for VOCs to travel through via groundwater or soil gas, and enter a building through man-made entrances like vents and faucets.

When these chemicals mix with the indoor air, they can lead to acute or chronic health problems, like headaches, mental status changes, and increased risk of certain cancers.

Vapor intrusion can also pose a threat when an infiltrated building contains flammable materials, as many VA compounds can act as a catalyst to cause an explosion.

This graphic illustrates how vapor intrusion can affect humans and life in nearby areas where VOCs are being used. If not realized or handled, VOCs can have harmful effects on the health and wellbeing of nearby residents.