Vapor Intrusion

What is Vapor Intrusion? When volatile chemicals or petroleum products are spilled on the ground or leak from underground storage tanks, they can give off gases, or vapors, that can migrate from the subsurface into overlying buildings (residences, commercial or industrial buildings, or other enclosed structures). Common products that can cause vapor intrusion include, but are not limited to: industrial de-greasers, dry cleaning solvents, and gasoline or diesel fuel. Vapors move through the soil and seep through cracks in slabs or basement floors and walls, openings for utility lines where pipes and electrical lines go through the foundation, crawl spaces below floors and other openings. Vapor intrusion is a concern because vapors can build up to a point where the health of residents or workers in those buildings could be at risk. The adjacent figure depicts the typical migration pathways of contaminated vapors into buildings.