THIS WEEK'S WORKSHOP EXPERT Russell Abell, P.G., Project Manager, Jacques Whitford Company, Inc. Portsmouth, NH "Vapor intrusion: An enviromental and financial risk facing entities and individuals today"

  As the environmental field continues to evolve, one of the recent concerns facing entities and individuals involved with property transactions is vapor intrusion. This issue is receiving significant attention at the state regulatory level, as indicated by the spate of vapor intrusion guidance documents becoming effective in the past five years. Vapor intrusion is also of significant concern for the U.S. Environmental Protection Agency (EPA), which has also developed a Draft Vapor Intrusion Guidance and has sponsored several technical sessions on this topic in the past five years. Although not directly addressed in the recently-effective All Appropriate Inquiry (AAI) Rule for Phase I Environmental Site Assessments (ESAs), consideration of this issue during due diligence is now a topic of significant discussion within the community of environmental professionals. With such interest at both the state and federal level, vapor intrusion is certain to become a routine part of due diligence and environmental actions at properties in general.

  So, what is vapor intrusion? Vapor intrusion results when contaminants migrate via soil vapor from contaminated soil, contaminated groundwater, or free product into a building. The contaminants then accumulate in the air of the building, thereby posing a potential health risk to occupants. This is significant because for many contaminants, sites that have been considered low risk or have even been closed may still have a vapor intrusion problem. Additionally, for certain contaminants the concentrations in groundwater do not need to be significantly elevated, nor does the water table need to be near the ground surface for vapor intrusion to be a potential risk. For example, in N.H., investigation for vapor intrusion is required for trichloroethene (TCE) if the concentration is 50 parts per billion (only ten times the groundwater standard) and if the building is within 100 ft. of impacted groundwater (vertically and laterally).

  For those acquiring properties, this can be critical at several levels, especially in N.H. First, if off-site contamination associated with the property of interest exists, investigation for vapor intrusion may be required even for sites being managed under a Groundwater Management Permit (GMP). Sites with an active GMP, although contaminated, have typically been considered sites where the environmental issues are well understood, the scope of required actions to address the contamination is typically well defined, and the costs are typically easily predictable. These are important criteria for managing business and environmental risk during property transactions. However, the potential for vapor intrusion could add significant additional investigation and clean up costs to a site and these potential costs may not be as easily predictable at the due diligence stage of a project.

  Second, if the property of interest is contaminated by off-site impacts, which typically represent a low risk from a financial environmental liability standpoint during property acquisition, additional considerations may be necessary due to vapor
intrusion. These considerations may include on-site testing to determine if there is a risk to occupants of current or proposed buildings, and/or the need for altered building construction design or installation of control mechanisms such as sub-slab venting to eliminate vapor impacts. These items will add additional costs to the project, the significance of which will depend on the size of the building(s) and the extent of the vapor intrusion problem.

  Third, in order to meet AAI liability protection criteria, testing for vapor intrusion issues on-site and off-site may need to be considered in certain situations. Depending on the extent of the problem or the potential problem, this could greatly increase the costs that the purchaser must expend on due diligence in order to be eligible to seek liability protection under this rule.

  As with all environmental issues that arise during due diligence, vapor intrusion is another area where business and environment risk must be weighed prior to completion of the transaction. In order to limit potential post-transaction environmental
liabilities and unplanned costs during re-development, Phase I ESAs should include an assessment of vapor intrusion concerns. Careful attention to historical releases on the property and surrounding properties, including review of available environmental data (e.g., a file review at the State regulatory agency where applicable), is necessary to assess the potential that vapor intrusion may be of concern. This issue can be easily managed with the right environmental professional and with the collection of useful information during due diligence. Understanding the risks and costs associated with vapor intrusion and other environmental issues will help a buyer make the appropriate business decisions, thereby minimizing post-transaction problems.

Russell Abell, P.G., is project manager of Jacques Whitford Company, Inc. Portsmouth, NH
For more information contact: realestate@jacqueswhitford.com
Visit our website at: www.jacqueswhitford.com

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