VOC & Vapor Intrusion Mitigation for Safer Buildings

Vapor intrusion occurs when volatile chemicals from contaminated soil or groundwater migrate into indoor air through cracks, gaps, or utility openings in building foundations. The chemicals involved are typically volatile organic compounds (VOCs) and semi-volatile organic compounds (SVOCs).

Is the building near a known or suspected contamination site?

Old gas stations, dry cleaners, landfills, factories, military bases, or industrial parks are common risk zones.

Check environmental records:

Look at federal/state databases (e.g., EPA’s Superfund sites, state brownfield sites).

Ask your local health or environmental agency.

If VOCs or petroleum-based compounds have been detected in soil or groundwater nearby, the building may be at risk—even if contamination is off-site.

Vapor plumes can travel hundreds of feet underground.

A sub-slab depressurization system (SSDS) is the most common and effective method for reducing radon and other soil gas vapors (like VOCs) from entering a building. It works by creating negative air pressure beneath the concrete slab of a building, which prevents contaminated gases from migrating indoors.

How It Works

1. One or more suction points are drilled through the concrete slab into the soil beneath (called the "sub-slab").
2. A network of PVC piping is installed to connect these suction points.
3. An inline fan (usually mounted outside, in an attic, or in a garage) pulls soil gases from under the slab.
4. The extracted gases are vented safely outdoors, above the roofline, where they dissipate harmlessly.

Yes, you can usually stay in the building during vapor intrusion mitigation.
In commercial or industrial buildings, mitigation may be staged or occur during off-hours to minimize disruption.

The cost of VOC (volatile organic compound) vapor intrusion mitigation can vary widely based on several factors:

 Cost Drivers

1. Size and complexity of the building
2. Type of foundation (slab, basement, crawlspace)
3. Level of contamination and chemical type (e.g., TCE, PCE, benzene)
4. Required mitigation system (simple vs. engineered)
5. Need for additional monitoring wells or vapor barriers
6. Regulatory requirements (especially for commercial/industrial sites)