One of the service areas that OTO’s clients value the most is our experience in addressing vapor intrusion. We have been a recognized leader in the field of vapor intrusion assessment for nearly twenty-five years.

Contact for Vapor

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Vapor intrusion is when chemicals that are ‘volatile’ (meaning they readily turn into a gas or vapor) migrate from impacted soil or groundwater into soil gas, which then passes into the indoor air within a building located above or near the impacted area. Two common examples of these volatile organic compounds (VOCs) are gasoline and the dry-cleaning solvent tetrachloroethylene. Since breathing is one of the main ways humans can be exposed to chemicals in the environment, vapor intrusion is an important consideration in environmental regulations.

Vapor intrusion can be a complex problem to solve, and is a common problem at dry cleaners, industrial facilities, gasoline stations, and brownfields, since a relatively small area of impacted soil or groundwater can create a big headache if it’s beneath a building.

OTO’s scientists and engineers have decades of experience working with vapor intrusion challenges in Massachusetts, Connecticut, and under the federal Superfund and RCRA programs. Our knowledge base includes hydrogeologic assessments to find the source area, soil gas and indoor air sampling, toxicological knowledge in conducting risk assessments, and the engineering and regulatory knowledge needed to solve the problem. Some of the remedies we have recommended in the past have ranged from minor modifications to building HVAC systems or the sealing of migration pathways such as floor cracks or pipe runs, to the chemical treatment of soil and groundwater or the incorporation of vapor barriers into foundations for new buildings. If necessary, we can design an engineering solution such as a sub-slab depressurization system, or SSDS, to redirect the soil gas to the outdoor air.

As with all our other work, our focus is on finding the most cost-effective and practical solution that both meets our clients’ goals and satisfies regulatory requirements.