USEPA Vapor Intrusion Guidance -- Need For A More Practical Approach

Analysis of Draft Final Vapor Intrusion Guidance Published by Bloomberg BNA

As reported on this blog at the time it was released, on April 16, 2013, USEPA's Office of Solid Waste and Emergency Response released for public input two draft vapor intrusion guidance documents: a general guidance for all compounds ("Guidance"); and one focused on petroleum hydrocarbons released from underground storage tanks. The documents can be accessed here. Public input must be submitted by the extended deadline, June 24, 2013, through Regulations.gov; docket number: EPA-HQ-RCRA-2002-0033.

We reviewed the general Guidance in some detail and published analysis as a BNA Insights article, Lawyers' View of EPA's Draft Final Guidance for Vapor Intrusion: Public Comments Are Needed to Advocate for a More Practical Approach, in the June 6 Bloomberg BNA Daily Environment Reporter. 

Some of our observations, which are  explained in the article, include:

1. In the Guidance and supporting materials, USEPA has produced a detailed, comprehensive approach to vapor intrusion investigations.
2. The Guidance articulates an approach that would potentially pull many, many properties into vapor intrusion evaluations, even where the likelihood of vapor intrusion is attenuated. Under the Guidance, "detailed vapor intrusion investigation" is triggered by information that indicates a potential for vapor forming chemicals to be present in the subsurface at a property and the actual or potential future presence of buildings nearby. Once this thin line is crossed, "multiple lines of evidence" are required to support a decision that no further assessment or response is necessary.   
3. The 'lines of evidence' required almost always are building-specific test results. For example, the Guidance even recommends that site-specific, and building-specific, test results (including perhaps indoor air results) be obtained to determine what buildings should be considered "near" the volatile source and subject to evaluation. The prior rule of thumb, 100 feet vertically and horizontally from the volatile source, apparently is viewed as not sufficiently reliable or protective.
4. Under the Guidance and VISL calculator, the volatile "source" areas are very conservatively drawn, for example, at as little as 1.1 ug/L of TCE in groundwater.
5. The vapor intrusion pathway may be "deemed complete" before any detections of vapors in indoor air or any human exposures are identified.
6. To address what appears to be an overwhelming agency concern about variation in vapor test results, the Guidance stresses the need for multiple rounds of testing, from multiple locations both in the environment and indoor air. 
7. The Guidance sets forth a framework for imposing low, short-term action levels that could lead USEPA to advise or direct occupants to evacuate buildings when sampling detects exceedances, especially as to TCE, the most common contaminant at Superfund sites.             
8. In general, the Guidance appears to overstate the risk of chemical vapor intrusion, especially in light of USEPA's own approach to radon vapor intrusion.
9. The Guidance lacks discussion of the potentially broad implications and challenges created for building owners, occupants, employers and employees, as well as responsible parties, that can arise because vapor intrusion guidance now increasingly directs testing for very low, common, and otherwise unregulated levels of chemicals in indoor air, and it identifies very low levels as unsafe for occupants. In other words, the Guidance and accompanying materials could be viewed as stating USEPA's determination of acceptable ambient indoor air quality levels for hundreds of common chemicals. However, while these levels will be rigorously enforced by USEPA if they result from vapor intrusion -- to the great confusion of owners and occupants and others -- they are left unaddressed if present from any other source. This difficult subject warrants significant discussion in the Guidance.  
10. Overall, our view is that the Guidance as currently written is likely impractical and potentially (and unnecessarily) disruptive to building owners and occupants.

We urge all interested parties to review the documents and provide comment to USEPA before June 24, 2013.   

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