Vapor Intrusion

by Paul French
May 25, 2017

What is Vapor Intrusion

Vapor intrusion (VI) is a contaminant exposure pathway resulting from the migration of volatile chemicals, such as petroleum and industrial solvents, from buried wastes, contaminated soil or groundwater into an overlying building with human receptors. Vapor intrusion can also occur from natural sources such as radon. An unacceptable VI exposure occurs when contaminants are present in indoor air at concentrations that could cause a risk to human health through inhalation, and/or a risk to public safety through fire or explosion. An unacceptable VI exposure may not only occur on the property where a spill or release occurred, but it can also occur in a business or residence on neighboring properties hundreds of feet away from the source property.

Evaluation of the VI pathway has come to the forefront in the recent years as new studies have shown that many contaminants (chlorinated compounds) may cause developmental effects in utero and in infants and small children and that significant health issues may result in any population from acute exposures. The Michigan Department of Environmental Quality's (MDEQ) Director, Heidi Grether has stated "it's a significant public health threat."

The MDEQ has begun to collaborate with the Department of Health and Human Services (DHHS) to enforce response action at sites with potential VI issues; including contaminated facilities that had been previously closed, and sites where chlorinated solvents were detected during the course of a property transfer and disclosed through a Baseline Environmental Assessment (BEA). The MDEQ and DHHS have developed a table of Action and Trigger Levels for VI sites, which dictates when vapor mitigation is necessary and/or evacuation of a building is warranted. The MDEQ and DHHS are aggressively pursuing these response actions at VI sites.

Due to the costs associated with investigation and mitigation of VI issues, and more importantly, the risk to human health and public safety, it is imperative that you and/or your environmental professional have a thorough understanding of the VI; including building assessment, soil gas and indoor air investigations, design and operation of mitigation systems and regulatory requirements. Failure to understand VI at your site may result in unnecessary costs to investigate or mitigation a potential VI issue; or in an unacceptable exposure to your family, employees or visitors.

VI Sub-slab Sample Collection

Sub-Slab Sample Collection

Let Envirologic help; we have comprehensive experience in all aspects of vapor intrusion including:

  • Soil and Groundwater Sampling
  • Soil Gas / Sub-Slab Vapor Sampling
  • Indoor Air Sampling
  • Pressure Field Extension Testing
  • Design and Installation of Sub-Slab / Crawl Space Depressurization Systems

If you have questions regarding VI testing, system design or regulatory issues, please contact Project Manager Paul French.

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vapor intrusion  indoor air quality  indoor air sampling  soil gas  sub-slab sampling  depressurization systems  mitigation system  regulatory requirements  mdeq  dhhs  exposure pathway  chlorinated solvents 

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