Clients responsible for sites where volatile organic compounds (VOCs) are found in soil or groundwater have discovered that vapors may migrate to the indoor air of overlying and adjacent buildings and result in health and safety risks to their occupants.

Assessing and mitigating the vapor intrusion (VI) pathway can be challenging for these clients because of factors that influence subsurface, building, and atmospheric conditions. It is critical for our clients to get vapor intrusion assessment, and mitigation when required, taken care of correctly the first time due to the risks that poorly conducted efforts potentially pose to human health. Many regulatory agencies have "look-back" contingencies for closed projects (e.g., U.S. EPA 5-year reviews) that allow a site to be reopened to evaluate VI risks at sites previously closed, and if deemed inadequate, can force the responsible party to spend even more money to correct the problem.

Geosyntec has the industry's largest toolbox to effectively evaluate VI potential and allow clients to move past routine sampling with rigorous, defensible data to confirm or rule out VI potential and provide effective mitigation only if required. Our VI practitioners continually lead the industry through applied researching, teaching, authoring peer-reviewed journal articles, and shaping regulatory guidance. When it comes to VI, we have guided the industry for many years - developing the Johnson & Ettinger model, writing U.S. EPA and Interstate Technology & Regulatory Council (ITRC) guidance and ASTM standards, and authoring hundreds of groundbreaking papers and presentations.

Geosyntec helped develop and were also invited reviewers of many state and industry guidance documents, including New Jersey DEP, California Department of Toxic Substances Control (DTSC), Electric Power Research Institute (EPRI), US Department of Defense (DoD), and many others. With this knowledge and insight, we provide clients with:

• Rapid and clear understanding of site conditions
• Credibility with regulators and stakeholders
• Creative, cost-effective solutions
• Implementing innovative solutions

Geosyntec has more highly experienced VI practitioners than any other consulting firm in the world. We have created a center of excellence that draws the best and brightest minds to provide the best service available. Our staff are geographically distributed throughout our offices, but function as one coherent team within the firm. We will always provide the right person for the job, and we can handle accelerated schedules by increasing project staff allocation better than any other firm.