I recently presented a series of five environmental due diligence seminars that spanned over several months. The seminars were part of continuing education classes for real estate professionals. My role was to provide an update on some of the more recent environmental developments. Of course, one of the main points I focused on was vapor intrusion (VI). We had some lively dialogue at each of these seminars about VI and other environmental issues – and yet, I don’t think the regulated community fully realizes what a potential nightmare VI represents.

Vapor Intrusion – How We Got Here

The more recent controversial VI development stems from a December 3, 2013, letter sent by EPA Region 9 to Stephen Hill, Chief of the Toxics Cleanup Division at the California Regional Water Quality Control Board. That letter outlined the EPA’s interim short-term indoor air response action levels of trichloroethylene (TCE) and recommended that those action levels be incorporated into all vapor intrusion evaluation work plans at Superfund sites in the South Bay (CA) area. We discussed this memo in our January 2013 blog, “Vapor Intrusion Guidelines Becoming More Conservative?”

Vapor Intrusion – The Controversy

As discussed in numerous blogs and articles, there are several problems associated with the recommendations from EPA Region 9 including using a precautionary principle approach to the assumed exposed group. For example according to the EPA, “The recommendations set forth in the attached memorandum address a particular concern for TCE focusing on protecting sensitive and vulnerable populations, especially women in the first trimester of pregnancy (because of the potential for cardiac malformations to the developing fetus).” Even though the EPA says that the “Scientific information on the exact critical period of exposure for this health impact is not currently available…”

Further, the action levels recommended by Region 9 are orders of magnitude lower than current scientifically-based OSHA guidelines. This was discussed in an article, EPA’s Concern Over TCE Vapor Intrusion is Misguided where the authors state, “Unlike Region 9’s conclusions regarding short-term exposure to TCE, the other agencies that set standards for short-term exposure to TCE set the permissible exposures orders of magnitude higher than the standards set in the EPA Memo and the December Letter. For example, the short-term exposure level for TCE under federal OSHA regulations is 537,000 µg/m3 for an eight-hour shift — 59,666 times greater than the short-term exposure standard set by the EPA Memo” (emphasis added).

I understand that OSHA is somewhat dated. But, that someone can be exposed in a workplace environment at nearly 60,000 times higher than someone might experience via vapor intrusion from subsurface conditions, seems to stretch even the most conservative view of exposure scenarios.

There have been many “calls” for EPA to reconsider this policy and to 1) use a more rigorous scientific approach (e.g., as was the case in developing OSHA and other guidelines) and 2) open this up for pubic and scientific comment (there was no public comment on this guideline). Considering the impact this may have on the economy, these calls certainly seem reasonable prior to implementing a sweeping mandate.

Basic Conceptual Site Model of Vapor Intrusion. Source: USEPA October 2010

Vapor Intrusion Caution for Real Estate Development

The environmental consulting community has wasted no time in marketing the vapor issue. My colleagues and I have written and presented on this topic – both in the US and in Canada – for several years. In the previous article I cited, the attorneys point to some “sensationalized headlines that encourage indiscriminate testing of vapor with no thought as to what to the data may mean or what regulatory snares may await an unsuspecting company who decides to take samples because they were advised to do so.”

We hope that the EPA will reconsider their approach to vapor intrusion, but in the meantime, we will continue to advise our clients to approach the issue of vapor intrusion with great caution and thoroughly consider the technical, legal, and business risks of their specific situation.

If you have a question about vapor intrusion and/or environmental due diligence, please feel free to contact me (jbolin@dragun.com) at 248-932-0228, ext 125.