Vapor Intrusion “Guidance” – What Now?

Diane Whitney

"The Fog comes in on little cat feet," according to Carl Sandburg, but the U.S. Environmental Protection Agency tells us that vapors come in through cracks in basements, utility lines, and the like — considerably less poetic and of greater concern. This concern may soon be heightened because EPA plans to issue a new vapor intrusion "guidance," probably before the end of this year.

A word about "guidance." The EPA, the Connecticut Department of Environmental Protection (DEEP) and other agencies issue "guidance" from time to time, rather than regulations. The difference in effect between the two is negligible, but the difference in procedure is substantial. This should not be the case. When an agency issues standards with which business must comply, those standards should be contained in properly promulgated regulations. Doing so takes longer that just publishing "guidance," but the longer process incorporates the checks and balances that guarantee, so far as possible, that the regulations were reviewed by stakeholders and experts and supported by reliable science. The result of the longer process is more secure and more trustworthy.

Instead, we are offered "guidance." What, exactly, is guidance and must we comply with it? The question is probably irrelevant, because if history is any predictor, the world will treat guidance like a regulation, and it will become one, in effect. Commercial lenders are swift to latch onto guidance and make compliance a requirement if they are to lend on the property. So whether the new vapor intrusion guidance is a regulation or not, you are well-advised to accept it as the new rule, despite its own disclaimer that the real standards for vapor intrusion are contained in the statutes and regulations.

Since at least 2002 there has been EPA vapor intrusion guidance in effect, with the regulated community looking forward to the eventual passage of a real regulation. It is not to be, at least not yet. The new guidance will probably be issued by December 2013, following a public comment period in 2011 and 2012.

Vapor intrusion is the migration of volatile organic compounds (VOCs) through contaminated soil and groundwater into buildings. The new 196-page guidance approaches the issue differently from the 2002 guidance, now emphasizing practical and preventative measures over scientific certainty. It applies to residential and nonresidential buildings and to undeveloped property. There are two guidance documents, one general, for all compounds, and one focused on petroleum hydrocarbons. Though vapor intrusion can cause explosions, the more common risk is to human health from chronic exposure. Testing for vapor intrusion can be tricky because many of the substances used in buildings contain the same VOCs that cause vapor intrusion issues.

The new guidance includes screening level concentrations and target risk levels for cancer and non-cancer effects. It also contains a Vapor Intrusion Screening Level Calculator to help determine whether a vapor intrusion pathway is likely to cause health problems. Among the goals of the new guidance are to update toxicity values to protect human health, to encourage the use of multiple lines of evidence in making vapor intrusion decisions, to apply the guidance to Superfund sites, to determine when and what mitigation efforts are called for and to determine whether deed restrictions are appropriate for vapor intrusion sites.

Though the most common source of vapor intrusion is contamination under an existing building, the new guidance warns that that is not always the case, that a source can be located on other property, causing a plume of contamination that leads to vapor problems some distance from the source. The presence of fractured bedrock, a high water table, or multiple underground utility connections adds to the likelihood that vapors will enter a building. The guidance appendix lists 117 vapor-forming chemicals that could cause intrusion problems.

The guidance expresses EPA's preference for early mitigation measures. It stresses that it is more important to end potential risk to inhabitants than to complete a comprehensive investigation before beginning mitigation. Based on this guidance, new construction in any area where historic contamination is possible may require a vapor barrier. Barriers remove any concern for the health of the occupants and are relatively inexpensive to install. Lenders aware of a vapor intrusion possibility are likely to insist on such measures. Existing buildings may be required to install active depressurization technology as the most practical solution for this problem. EPA refers to these measures as "preemptive mitigation/early action" and encourages them.

For nonresidential buildings such as schools, libraries, hospitals, hotels and industrial buildings in contaminated areas, investigation is strongly suggested. If no investigation is performed and the building comes to EPA's attention, justification must be provided for the decision not to investigate. Investigation is encouraged even for undeveloped property in areas where contamination is possible, with deed restrictions suggested to control future development in a manner protective against vapor intrusion effects.

As with the 2002 guidance, there is a question of whether closed Superfund sites might be reopened to deal with vapor issues, and the answer seems to be a strong "maybe." That possibility is mentioned; if a site exhibits vapor intrusion that poses a risk to human health, reopening the site is likely. EPA is supposed to review Superfund sites every five years; that review could reveal unresolved vapor issues that need attention now. Vapor intrusion will be added to the hazard ranking system for inclusion on the National Priorities List.

As has happened in the past with guidance documents, the new vapor intrusion guidance will probably become the standard for dealing with the issue. It represents EPA's best thinking on the subject and is likely to be considered gospel until a new guidance, or maybe even a regulation, comes along.


Diane W. Whitney chairs the Environmental Law Department at Pullman & Comley in Hartford. Reprinted with permission from the October 11th issue of Connecticut Law Tribune. ©2013 ALM Properties, Inc.  Further duplication without permission is prohibited.  All rights reserved


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