Contaminant Vapor Intrusion Into Structures – Do You Know The Risks?

In 2010, the American Society for Testing and Materials (ASTM) issued a standard (ASTM E-2600-10) for conducting a Vapor Encroachment Condition (VEC) on property involved in real estate transactions with respect to volatile contaminants (e.g., solvents, gasoline) that can migrate as vapors into existing or planned structures. Possible sources for volatile contaminants could include dry cleaners, leaking underground storage tanks, or old landfills to name a few. Since introduction of this new standard in 2010 and the previous 2008 standard, not all Phase I Environmental Site Assessments (ESAs) associated with property transactions have included a VES, potentially leaving the buyer and/or lender facing a potential loss in property value, cleanup costs, or possible lawsuits if a Vapor Encroachment Condition (VEC) exists.

What should you do? If you are buying a property and are having a Phase I ESA completed, insist that your environmental consultant include completion of VES, as warranted.

On the national front, the Environmental Protection Agency (EPA) on January 31, 2011, has moved vapor intrusion to the forefront by presenting a proposal to add a vapor intrusion element to its Hazard Ranking System. This action by the EPA underscores the risk to human health posed by vapor intrusion of volatile chemicals.

What to do if a VEC Exists? A VES follows a tiered process to determine whether a VEC exists on a property. A Tier 1 screen is completed first followed by a Tier 2 screen. A Tier 2 screen can include both non-invasive and invasive data collection such as sampling indoor air, soil, and/or groundwater If a VEC is identified through additional analysis or testing, a buyer can choose to walk away or the property owner may develop methods to mitigate vapor intrusion issues. For undeveloped properties, methods to prevent vapor intrusion are relatively inexpensive to incorporate into site development and building design. For existing buildings, methods are typically more costly.

In related news, the Oregon Department of Environmental Quality (DEQ) has recently developed guidance for assessing whether a vapor intrusion condition exist at a property where a subsurface release of hazardous chemicals has impacted soil and groundwater. At cleanup sites, we have seen a spike in direct sampling to evaluate health risks from vapor intrusion into on-site buildings and outdoor air. While DEQ guidance has been available since March 2010, we have seen recent increasing scrutiny as DEQ project managers become apprised of the technical issues. For more information about Vapor Intrusion Assessments, Indoor Air Sampling, or Phase I ESAs, please contact Randall J. Boese at BBA Environmental at 503-570-9484, ext. 1.

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