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Subsurface Vapor Mitigation System Design and Implementation

Geosyntec Consultants maintains an international reputation as one of the preeminent firms for the assessment and mitigation of subsurface vapor intrusion to indoor air. We earned our reputation by providing 25 years of innovation in applied research and practical project experience to the challenges presented by vapor intrusion at sites all over the world.

Clients seek us out for customized solutions founded in an understanding of physical, chemical, and biological processes. We design our solutions to add value and address risk by targeting corrective actions where they are warranted. Additionally, our professionals published the most widely cited and used vapor intrusion model (Johnson and Ettinger, 1991), and we have performed pioneering modeling of aerobic degradation of hydrocarbon vapors with the 3-D model of Abreau and Johnson (2005).

Geosyntec engineers and scientists are co-authors or contributing editors of guidance and regulatory documents that outline and advocate the latest advancements and research related to the remediation of vapor intrusion around the world. These include standards, information supplements, and handbooks issued by the U.S. Environmental Protection Agency, the Electric Power Research Institute, the Interstate Technology and Regulatory Council, and ASTM International, formerly known as the American Society for Testing and Materials. The efforts associated with this public involvement represent significant steps forward in the evolution of vapor intrusion assessment and control technology.

We provide engineering services for vapor intrusion mitigation system design, construction, operation, trouble-shooting, and repair for both passive and active systems, including real-time control and monitoring services. We also are pioneers in the use of aerated flooring in the United States as a cost-effective way to manage risk, particularly in new construction. Our patented sub-slab venting system is in use at brownfield sites found throughout the country. Our current research explores the use of wind- and solar-powered systems for sub-slab ventilation.

Additionally, Geosyntec practitioners have long-established credibility and expertise in the negotiation of regulatory approvals for our clients' vapor intrusion solutions. Our engineers and scientists participated in the development of more than a dozen regulatory guidance documents on vapor intrusion during the past two decades. Clients rely upon this depth of knowledge and experience to negotiate sensible and cost-effective scopes of work among local, state, federal officials.

Geosyntec's legal clients represent some of the world's largest corporations. Our practitioners have extensive experience in providing litigation support in cases involving dozens of sites where vapor intrusion or subsurface gas migration have resulted in claims. These include cases touching on issues of human health impacts, medical monitoring, and property devaluation. We also specialize in management and access to large, complex databases for joint-defense groups.