Questions About Vapor? Documentation, Professional Judgment, Sampling and More

Q&A With A Trio of Vapor Experts  


On June 24, 2014, EDR Insight hosted a webinar, titled Vapor Migration as a Recognized Environmental Condition: Now What? Three leading experts on vapor migration and vapor intrusion shared with more than 1,000 attendees the latest intelligence on how vapor migration risk is being handled on today’s property deals. Teaming up for the event were:

David Gillay, Partner and Chair of Brownfields & Environmental Transactional Diligence Practice Areas, Barnes & Thornburg LLP
John B. Sallman, P.G., Senior Principal, Assistant Director of Environmental Services, Terracon Consultants, Inc.
Blayne Hartman, Ph.D., Hartman Environmental Geoscience, Vapor Intrusion, Soil Gas & Analytical Support

Due to the high volume of questions submitted during the live event, we were unable to address all of them in the available time frame.  The questions not addressed during the webinar are below, followed by answers provided post-event by our speakers.

Q: Where in ASTM 1527-13 does it state that a method needs to be followed for a vapor encroachment assessment?
JOHN SALLMAN: Section 1.1.5 requires that documentation of resources used to make your inquiry must be provided.  If your scope of work includes a vapor screen, then you would need to have a reproducible method for conducting that screen along with the proper documentation so that the user could reproduce the screen with the same results.

Q: Please repeat the definition for vapor encroachment.
SALLMAN: A VEC is defined as the “presence or likely presence of chemicals of concern (COC) vapors in the sub-surface of the target property caused by the release of vapors from contaminated soil or groundwater either on or near the target property as identified by Tier 1 or Tier 2 procedures.”

Q: What good is a file review when no one was checking for vapors in the past?
SALLMAN: If you are referring to an on-site release, the file review can tell you what the concentrations were at the time of closure and whether there may be a vapor issue on the site.  It may also show where a previous release occurred on the site.  It is possible that site redevelopment could be planned to avoid development over the plume area. If you are referring to off-site files, then the file review can tell you where the edge of the plume is so that you can apply the critical distance test and possibly resolve a vapor encroachment issue.
DAVID GILLAY: You may want to consider this as a potential data gap, and also give consideration to what state or regional VI guidance potentially applies to the particular site.

Q: I think John mentioned that it had to be documented in the report how vapor was evaluated.  If you don’t use E2600, how is this being documented?  Would this be hard to do without a separate vapor section?
SALLMAN: I may not have been clear on this on the webinar.  If you are conducting a Vapor Encroachment Screen (or similar service) as part of your Phase I environmental site assessment, you would need to document how you evaluated the vapor pathway.  Many consultants choose E-2600, but most are using a modified E2600 and provide a short description of their vapor encroachment evaluation process in the report.  Another alternative would be to have a written internal method that is utilized that can be referenced and provided to the user so that the user can reproduce the same results.  Please note that this process is only required when conducting a vapor screening of some sort.  If you are conducting an E 1527-13 Phase I ESA, then it is implied that you are evaluating the vapor pathway and documentation of how you complete that evaluation is not required, just as it is not required for the soil or groundwater pathways.  That being said, documentation of the resources used to make your inquiry during the Phase I ESA is required (i.e., topographic maps, files reviewed, aerials, etc.).

Q: Several times you indicated that vapor intrusion is seldom the sole contaminant pathway.  Yet the problem we are having is working with the 1/3 mile distance for VOCs.  How do we address this issue believing that a site is not a problem within 1/3 of a mile without leaving us open to future liability?
SALLMAN: E-2600 allows for the use of professional judgment.  You can screen out potential vapor sources based on topographic/hydrogeologic divides, average plume length in your local area, etc. which all are part of professional judgment.  Most really large local plumes are well known due to their size, thus for the few plumes that exceed that distance, most professionals working in a single or a few local markets are well aware of the nature and extent of those “famous” plumes.  Please note that this process is only required when using E2600.

Q: Blayne Hartman said that the issue of vapor intrusion is abated for petroleum constituents (vs chlorinated solvents); please elaborate.
BLAYNE HARTMAN: Because of bioattenuation, hydrocarbon vapors rarely make it from the contamination source through the vadose zone to the building.  Very few documented sites of petroleum vapor intrusion exist relative to chlorinated compounds.

Q: Blayne Hartman made a comment to test for chlorinated under the slab, but hydrocarbons outside.  Why the difference?
HARTMAN: In the majority of cases, bioattenuation in the shallow soil column under and adjacent to buildings results in equivalent soil vapor concentrations near and under buildings.  This is not the case for chlorinated compounds.

Q: Does a Tier 2 (Phase 1.5) usually require two rounds six months apart or a one-time deal?
HARTMAN: The Tier 2 investigation is quick.  Field work is usually done within a couple of days, and then the report within a couple of weeks after the field work is completed.

Q: You mentioned that E2600 has 4 tiers.  If I remember correctly, E2600-10 deals with vapor encroachment and has two tiers.  E2600-08 had four tiers, deals with vapor intrusion and has been withdrawn.  Please clarify.
HARTMAN: I stand corrected.  Thank you for pointing this out.  I obviously need to update my slides on this issue, and will do so.

Q: We have a potential borrower who owns a historic downtown building.  Two blocks away, there’s a former dry cleaner from the 1930s that created a plume under our building.  Our building owner has an above-ground storage tank in the basement that leaked and filled the basement with 1 inch of oil.  If this oil possibly leaked through the slab, should we require a vapor test when the results could be compromised by the dry cleaner plume?
HARTMAN: A complete answer needs more information, but here are my initial thoughts. If the oil leaked from your building, why would you test under the building for oil-related compounds?  Does the building have multiple units/tenants that you are worried about?  You would want to test for PCE if you want to know if PCE vapors from the former dry cleaner are underneath your building.

Q: Many states have Risk Based Corrective Action or other guidance/requirements for petroleum vapors, but how do you determine vapor migration for other VOCs?
HARTMAN: Most states have screening levels for non-petroleum VOCs.  For those that don’t, you can determine your own using the EPA’s regional screening levels (RSLs).

Q: I work for a lender.  Do we/our borrower have CERCLA protection for vapor if our Phase I ESA was written, say 2 years ago, under the E 1527-05 standard?  Also, what type of CERCLA protection do we have if we get a reliance letter for a Phase I ESA conducted under the previous E 1527-05 standard?  Do we need to ask the Phase I engineer who issues the reliance letter to add some sort of vapor addendum with the reliance letter?
GILLAY: These are excellent questions and highlight the confusion that flows from the U.S. EPA’s recent direct final and proposed AAI rules and statements made in the preambles. I suggest a phased approach that starts with a careful, independent review of the Phase I ESA in question. I would next contact the Environmental Professional and discuss how/whether vapor migration was covered during the AAI work. You should then evaluate the responses and consider next steps to protect your client/lender.

Q: If there are 30 historical dry cleaners within 1/3 of a mile, and 5 gasoline USTs within 1/10 of a mile, with no leaks or spills reported, would we state that there is a REC at the site? Or would we say that there is a potential for vapor migration at the subject site?
GILLAY: The determination of what constitutes a REC is up to the professional judgment and experience of the EP, taking into account the site-specific features of the target property including, among other things, surrounding property use, depth to groundwater, potential receptors, etc. If there is a lack of information about potential off-site property uses, then the EP may want to consider whether this is presents a data gap.

Q: If you have a dry cleaner on an adjacent site and it’s listed on the regulatory database as a historical dry cleaner, but no leaks or spills are reported, should your Phase I ESA report document this adjacent site as a REC, or a high environmental risk? And would you recommend sampling along the border to make sure?
HARTMAN: Many dry cleaners have invisible “vapor leaks” from the washer unit, so even though no liquid leaks/spills are reported, there could still be a PCE plume emanating from under the building slab to nearby tenants (in a strip mall) or buildings.  So yes, I would advise my client to test the soil vapor at the property border.


A replay to EDR Insight’s webinar titled Vapor Migration As a Recognized Environmental Condition: Now What? is available online.

The slides used by David Gillay, Blayne Hartman and John Sallman can be found here.

Access to EDR Insight’s past content on the vapor migration/vapor intrusion topic are posted here. 

Article titled Identification of Vapor Migration at Site Not a `Deal Killer,’ Attorney Tells Webinar. Reproduced with permission from Daily Environment Report, 122 DEN A-6 (June 25, 2014). Copyright 2014 by The Bureau of National Affairs, Inc. (800-372-1033)