Vapor intrusion (VI) is the movement of chemical vapors from contaminated soil and groundwater into a structure. Chemical vapors primarily enter buildings through openings in foundations or basement walls, which may include cracks in the concrete slab, gaps around utility lines, and sumps. Once inside the building, vapors may be inhaled, posing immediate or long-term health risks to building occupants.
Technical Resources for Vapor Intrusion Mitigation (VIM) is designed to aid state regulators in understanding various mitigation strategies, how they are installed and fundamentally work, and what factors to consider as part of the review process. This training and web document are intended to guide regulators and project managers through the critical elements of selection, design, implementation, and operation of VIM.