New ASTM Standard Practice for Assessment of Vapor Intrusion In Real Estate Transactions: More Harm Than Good?

March 19, 2008Articles The Bureau of National Affairs, Inc. Environmental Due Diligence Guide

Reprinted with permission from BNA, Inc's Environmental Due Diligence Guide.

Recent increased attention to the migration of volatile chemicals from subsurface soil or groundwater contamination into buildings has raised concern about the evaluation of vapor intrusion in the process of buying and selling real property. In response, ASTM International’s Subcommittee on Real Estate Assessment and Management developed a standard practice, released March 3, to be used as a tool to evaluate vapor intrusion in that context. The author of this article is the sole member of subcommittee E 50.02 whose negative vote was not withdrawn after the final ballot in December 2007. In this article, he explains how this standard undermines ASTM Phase I standard E 1527-05 on all appropriate inquiries and directs environmental professionals to speculate about unacceptable risks in indoor air of inhabited buildings. He also explains why these results are potentially harmful and unnecessary.

231.1941 Introduction*

Vapor intrusion is the migration of volatile chemicals from subsurface soil or groundwater contamination into overlying buildings. The chemicals volatilize from the impacted soil or groundwater and migrate as soil gas through pore spaces in soil toward areas of lower pressure and chemical concentration (usually toward the surface). The soil gas can enter buildings through cracks in foundations and utility conduits. The chemicals that enter a building have the opportunity to accumulate and cause human exposures to a degree they would not if dispersed in open, ambient air.

At least three things are true about the potential for volatile contaminants to migrate into buildings as vapors (vapor intrusion):

1. Vapor intrusion is subject to growing scrutiny.

2. Vapor intrusion determinations are complex and are not made easily.

3. Vapor intrusion determinations inherently are high stakes because they are determinations about unacceptable health risks in the breathing air of building inhabitants.

With these truths as backdrop, ASTM International, through its Committee E50 and Subcommittee E50.02, set out to develop a tool for evaluating vapor intrusion issues in the context of the purchase and sale of real estate. The result is E 2600-08 Standard Practice for Assessment of Vapor Intrusion into Structures on Property Involved in Real Estate Transactions (VI Standard Practice). Unfortunately, the VI Standard Practice does not adequately take into account items two and three above.

Moreover, in issuing this VI Standard Practice, Committee E50 decided it needed to ‘‘clarify’’ its own Standard Practice for Environmental Assessments: Phase I Environmental Site Assessment Process (E 1527-05). E 1527-05, of course, has been deemed by the Environmental Protection Agency to satisfy ‘‘all appropriate inquiries’’ under the federal superfund law1 and the regulations promulgated thereunder.2 ASTM E 1527-05 provides the guidelines for the Phase I environmental site assessments performed everyday. This clarification of the existing standard is unfortunate as well as being unnecessary and unjustified.

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