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.

Lead Consultants

  • Nancy Bice, P.G., CEG

    Nancy Bice is a Senior Principal Engineering Geologist based in California with more than 20 years of experience focused on the characterization and remediation of sites impacted by volatile organi ...
  • Karen Berry-Spark

    Karen Berry-Spark is a Senior Principal Hydrogeologist based in Ontario with more than 20 years of professional experience focused on the characterization and remediation of sites impacted by chlor ...
  • Helen Dawson, Ph.D.

    Helen Dawson is a Principal Civil and Environmental Engineer based in Washington, D.C. with more than 30 years of experience focused on private practice, academia, and public service. Her practice ...
  • Todd McAlary, Ph.D., P.Eng., P.G.

    Todd McAlary is a Senior Principal Engineer with more than 25 years of international consulting experience focused on the evaluation of contaminant fate and transport in soil and groundwater. ...
  • Robert Ettinger

    Robert Ettinger is a Senior Principal Environmental Scientist based in California with more than 20 years of professional experience focused on the fate and transport of contaminants in the unsatur ...
  • Peter Zeeb, Ph.D., P.G., LSP

    Peter Zeeb is a Senior Principal Hydrogeologist based in Massachusetts with more than 20 years of experience focused on investigation and remediation strategy at some of the most challenging sites ...
  • David Folkes, P.E.

    David Folkes is a Senior Principal Environmental Consultant based in Colorado with more than 35 years of experience focused on environmental and geotechnical consulting throughout the United States ...
  • Beau Hodge, P.G.

    Beau Hodge is a Principal Geologist based in North Carolina with more than 25 years of experience focused on environmental site investigation and remediation with a focus on recalcitrant compounds ...
  • Greg Corcoran, P.E.

    Greg Corcoran is a Senior Principal Civil Engineer based in California with more than 25 years of experience with a focus on the design, construction, and operation of engineered systems for waste ...
  • Sam Williams, P.G.

    Sam Williams is a Senior Principal Hydrogeologist based in California with more than 25 years of experience focused on the characterization and remediation of soil and groundwater contamination at ...
  • Duane Graves, Ph.D.

    Duane Graves is a Senior Principal Scientist based in Tennessee with more than 30 years of experience focused on environmental biotechnology; environmental forensics; in situ groundwater, soil, and ...
  • Mark Grivetti, P.G., CHG, CEG

    Mark Grivetti is a Senior Principal Hydrogeologist based in California with more than 30 years of experience focused on characterization and remediation of hazardous waste sites, surface and ground ...
  • Susan Welt, M.P.H., P.E.

    Susan Welt is a Senior Engineer based in New York with almost 20 years of experience focused on the investigation and remediation of industrial sites, former manufactured gas plants (MGP), mining o ...
  • Chris Herin, P.G.

    J. Chris Herin is a Senior Principal Hydrogeologist practitioner in the field of environmental risk management and minimization based in Florida with more than 25 years of experience focused on the ...
  • Tom Peel, Ph.D.

    Tom Peel is a Senior Principal based in Florida with more than 20 years of experience focused on environmental science and engineering including the development of regulatory and risk-based strateg ...
  • Keith Tolson, Ph.D.

    Keith Tolson is a Senior Principal Environmental Scientist with more than 15 years of experience focused on environmental sciences. He Specializes in the application of risk-based principles to sup ...
  • Mary deFlaun, Ph.D., BCES

    Mary deFlaun is a Senior Principal Environmental Scientist based in New Jersey with more than 20 years of experience focused on the development and implementation of in situ remediation technologie ...
  • Scott Drew, LSRP

    Scott Drew is a Principal Environmental Scientist based in New Jersey with more than 25 years of experience focused on the fields of environmental technology, site remediation, and environmental ch ...
  • Peter Dollar

    Peter Dollar is a Principal Hydrogeologist based in Ontario with more than 20 years of experience focused on site characterization, remediation strategy, remedial design and implementation, and ris ...
  • Todd Creamer, P.G.

    Todd Creamer is a Principal Geologist based in New England with more than 20 years of experience in environmental consulting services, surface water hydrology, and oil and natural gas exploration a ...
  • Robert Glazier, P.G.

    Robert Glazier is a Principal Environmental Consultant based in Maryland with more than 30 years of experience focused on site remediation, risk assessment, and environmental permitting associated ...
  • Daniel Schauer, P.G.

    Daniel Schauer is a Senior Principal Geologist based in Florida with over 24 years of geological, hydrogeological, and geotechnical engineering consulting experience focused on multidisciplinary en ...
  • Jeffrey Kurtz, Ph.D.

    Jeffrey Kurtz is a Senior Geologist based in Colorado with more than 30 years of experience focused on geochemical assessments, site investigations, and environmental forensics. Helping cli ...
  • Robert Veenstra

    Robert Veenstra is a Principal Environmental Engineer based in Missouri with more than 30 years of experience focused on developing and managing complex soil, groundwater and sediment investigation ...
  • James Cowart, P.E.

    James Cowart is a Senior Consultant based in Colorado with more than 35 years of experience focused on water quality permitting, industrial wastewater treatment, and watershed management throughout ...
  • Eric Tollefsrud, P.G.

    Eric Tollefsrud is a Principal Hydrogeologist based in Minneapolis with more than 25 years of environmental consulting experience focused on the characterization and remediation of soil, soil vapor ...
Geosyntec Consultants
Geosyntec is a specialized consulting and engineering firm that works with private and public sector clients to address new ventures and complex problems involving our environment, natural resources, and civil infrastructure.

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