One of my colleagues in our US office recently completed presenting a series of five environmental seminars that spanned several months. The seminars were part of continuing education classes for a group of real estate professionals. His role was to provide an update on some of the more recent environmental regulatory developments. One of the main points he focused on was vapour intrusion (VI). My colleague said, “The group had some lively dialogue at these seminars about VI.” It seems anytime we do a seminar that involves VI, the discussions are always lively. (If you would like additional background on VI, see this 2011 article by two of my colleagues in Environmental Science and Engineering Magazine).
Vapour Intrusion – The California Controversy
We’ve learned over the years to watch trends in environmental enforcement in the US and, in particular, in California. Often, what happens on the West Coast of the US works its way eastward and northward into Canada. The recent VI controversy that began to brew in California started with a December 3, 2013, memorandum sent by the USEPA Region 9 to the Chief of the Toxics Cleanup Division at the California Regional Water Quality Control Board. That memo outlined the USEPA’s interim short-term indoor air response action levels for trichloroethylene (TCE) and recommended that those action levels be incorporated into all vapour intrusion evaluation work plans at Superfund sites in the South Bay (CA) area. A Superfund site is a site (contaminated with hazardous substances) designated by the US Federal Law to be cleaned up using federal funds. We discussed this memo in our January 2013 (US) blog, “Vapor Intrusion Guidelines Becoming More Conservative?”
As discussed in numerous blogs and articles, there are several problems associated with the recommendations from USEPA Region 9, including using a precautionary principal approach to the assumed exposed group. For example, according to the USEPA, “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 USEPA 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 the existing scientifically-based OSHA (Occupational Safety and Health Administration – United States Department of Labor) 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 USEPA Memo and the December memo. 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 USEPA Memo” (emphasis added).
California Memo v. OSHA
The exposure standard in OSHA is admittedly somewhat dated. With that being said, the idea that someone can be exposed in a workplace environment at nearly 60,000 times higher than someone might experience via vapour intrusion from subsurface conditions, seems to, at a minimum, suggest that there might be a disconnect between the two regulatory agencies. Is it possible for two different regulatory agencies to communicate with each other in order to better understand why this discrepancy exists? Are the OSHA exposure levels appropriate based on sound current toxicological data? Is this USEPA memo a red flag to let the regulated community know that OSHA TCE exposure levels need to be revised, not necessarily to the levels outlined in the December memo, but at least recalculated to incorporate current toxicological data?
There have been many “calls” for the USEPA 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 industrial/manufacturing sector, relative to decisions to mitigate or remediate, these calls certainly seem reasonable prior to implementing a sweeping mandate.
Vapour Intrusion In Canada
Over the past several years, we’ve conducted seminars and written articles regarding VI. We have consistently cautioned our clients to carefully consider a measured approach to assessing VI. We are maintaining a “watchful position” regarding the ultra conservative approach regarding VI in California, and we hope that the USEPA will reconsider their approach to vapour intrusion. We are also hopeful that a more scientific approach will preclude widespread adoption of this approach to VI (in Canada or the US).
In the meantime, we will continue to advise our clients to approach the issue of vapour intrusion with great caution and thoroughly consider the technical, legal, and business risks of their specific situation. If you have a question about vapour intrusion, please feel free to contact me (cpare@dragun.com) at 519-979-7300, ext 114.