Hello and welcome everyone. My name is Dane Menke. I am the digital marketing manager here at Regenesis and LandScience. Before we get started, I have just a few administrative items to cover. Since we’re trying to keep this under an hour, today’s presentation will be conducted with the audience audio settings on mute. This will minimize unwanted background noise from the large number of participants joining us today. If the webinar or audio quality degrades, please try refreshing your browser. If that does not fix the issue, please disconnect and repeat the original login steps to rejoin the webcast. If you have a question, we encourage you to ask it using the question feature located on the webinar panel. We’ll collect your questions and do our best to answer them at the end of the presentation. If we don’t address your question within the time permitting, we’ll make an effort to follow up with you after the webinar. We are recording this webinar. Any link to the recording will be emailed to you once it is available. In order to continue to sponsor events that are of value and worthy of your time, we will be sending out a brief survey following the webinar to get your feedback.

Today’s presentation is the second in a two-part series on risk and liability, and will focus on vapor intrusion mitigation and managing liabilities. With that, I’d like to introduce our presenters for today. We’re pleased to have with us Eric Leitz, Director for RPS Legacy Site Services. Eric Leitz has almost 25 years of experience in the environmental field, overseeing site investigation and remediation of soil, soil, gas, and groundwater for industrial, commercial, municipal, and residential clients. He draws on this deep experience to generate liability estimates related to acquisitions of facilities with operations with suspected or known vapor intrusion concerns and to advise on appropriate mitigations. These vapor intrusion evaluations are designed to provide realistic liability profiles that can be used to guide facility operations or acquisitions in both the short and long term.

We’re also pleased to have with us today Ryan Miller, East Region Manager of the Land Science Division of Regenesis. Ryan Miller’s role includes providing technical support in the design and installation of terra-shield, nitro-seal, mono-shield, and retro-coat vapor mitigation systems, and educating the environmental community on the advancements in vapor intrusion barrier technology, implementation, and quality control by making presentations to environmental firms, regulatory agencies, and developers. Ryan has extensive experience in the environmental consulting industry, most recently working as a New Jersey licensed site remediation professional focusing on brownfield redevelopment projects and specializing in vapor intrusion mitigation. All right, that concludes our introduction, so now I will hand things over to Ryan Miller to get us started.

Thanks a lot, Dane, for that introduction. I will kick this off with a discussion on vapor intrusion mitigation and managing liabilities. By going through a project LandScience was recently involved in, and then I’ll hand it over to Eric, who will talk about this topic in much more detail. So as a quick outline, I’m going to provide a brief overview on preemptive VI mitigation, especially at new construction projects, and why that may make sense. I’ll go through some general considerations if you or your client are evaluating the use of a vapor barrier, and then finally I’ll wrap it up with a discussion on the recent project where selecting the proper vapor barrier really made a huge difference for the success of the product. So there are a lot of reasons why we elect to mitigate vapor intrusion during construction.

For starters, I think VI is always a concern. At the end of the day, you have very little control over the adjacent property owner and if they have a spill, just as an example. If you do have an onsite source, the off-ramp to document that mitigation at that new building is not necessary isn’t always a simple task. So it typically requires a lot of investigation or characterization. Adding to the complexity of that is the speed of any development project. So oftentimes that’s a critical factor. So the additional investigation or characterization isn’t always an option for your client. So ultimately, even low risk sites end up getting pushed into preemptive mitigation. We’re seeing developers become more aware of long term risks associated with vapor intrusion And they elect to reduce their liability by implementing some sort of mitigation method up front. And so I think that last bullet is really the focus of today.

When it comes to passive mitigation approaches at new construction projects, the use of a contaminant vapor barrier is a common approach these days. Vapor barriers, unfortunately, aren’t always created equal and wading through the differences can be difficult. So what are some of the factors to consider? The first factor there that’s highlighted is chemical resistance. So chemical resistance is often the first thing design engineers and regulators look at. Will this vapor barrier block this contaminant? It’s a fairly simple and straightforward question. It’s a little bit more nuanced than that. So feel free to reach out to me directly if you have questions on chemical resistance, because it could be a topic for another webinar.

Next up is constructability, which includes a lot of terms like durability, ease of installation, a certified installation. Constructability is a crucial component in this vapor barrier selection process. You can have the most chemically resistant vapor barrier in the world, but if it can’t be installed in a timely manner, or the seams can’t be installed properly, or you have an unqualified contractor installing it, then how confident can you be that that system is being installed correctly? Are you really reducing any future liability? So not using an experienced contractor turned out to be one of the fatal flaws in this upcoming case study. And then finally, I just want to touch on cost because if we’re being honest, that is an important factor at the end of the day. With respect to cost, it’s vital to keep in mind what actually goes into the cost of any vapor barrier system.

Obviously, you have the material cost, the cost to install the barrier, but what about the QAQC procedures, such as smoke testing? Are those included in the cost? What about oversight or field coordination or potential repairs that are needed during the install? There’s a lot of things that start to add up that will factor into the cost. So let’s look at the case study. I think it helps highlight some of these points. So this warehouse development was speculative in nature, meaning they didn’t have any tenants when construction started. As a result, they needed to maintain flexibility with their schedule. The development had over five buildings, all of which were larger than 300 ,000 square feet. So just the sheer size of the project really magnified every decision, including the vapor barrier installation. The general contractor, the developer, they were relatively new to using contaminant vapor barrier. So they weren’t able to rely on any of their prior or past experience when it comes to the installation. So what happened?

The first building, when that went to construction, the project team went with a vapor barrier based on perceived lowest cost, meaning they only looked at the material cost and the installation cost. I don’t believe they even really even considered the ramifications of using a vapor barrier that lacked durability and was in constant need of repair during the installation. So this vapor barrier used tape to seal the seams and utility penetrations, which you can see from this picture on the right, took a significant amount of time, especially when you’re dealing with hundreds of thousands of square feet. So because the system used tape, it was nearly impossible to smoke test. So there’s a tremendous amount of time spent fixing the seams and penetrations just to pass the smoke test. So all of those things really added up to a lot of time and a lot of money and it really became an impediment. So on the remaining buildings, the rest of the project, the team realized they needed to make a switch and they ended up selecting MonoShield for the rest of the project.

MonoShield provided greater durability, it increased the speed of application and made all the QAQC procedures much easier. So these were all things that kind of plagued that first building. So here’s a better shot of MonoShield. The sheets rolled out on the photo on the right. On the left is a detail showing the MonoShield vapor barrier system. It would be helpful to kind of go through the installation process and it will highlight why MonoShield was such an improvement over the vapor barrier that was initially selected. So here’s a picture of the MonoBase rolls. You can see the black component is the geotextile fabric that’s bonded to the underside of of monosheild, this provides a lot of protection against the subgrade, the gravel, the stone layer that you see on the far right bottom of this photo. So that geotextile really increases the durability of the system.

One of the main reasons monosheild can be installed as fast as it can be is because the seams are sealed together. So they’re sealed together with a spray applied nitrile advanced asphalt latex core, as kind of shown in this photo here. This is another shot of the seams being spray applied, which creates a seamless barrier below the building. This really highlights, I think, how easy and efficient MonoShield can be applied. The area you’re looking at here is roughly 30 ,000 square feet, which was completed in about half a day. You compare that to a taped system that gets installed, you’re looking two to three times longer. In addition to the seams, all the penetrations and perimeter terminations are sealed with spray applied core material as well. So once again, an effective seal can be accomplished much quicker and easily confirmed with a smoke test.

So I wanted to wrap up with kind of what went wrong with the first building, kind of a lessons learned and then compare that to what works so well for the rest of the project. So the first building, the main issue was the use of a tape vapor barrier system. Everything kind of cascaded off of that. It just takes a lot longer to install, easily two to three times longer, and it doesn’t allow for easy QAQC, which again adds more time to the project by trying to fix those issues. The tape system is also a 20-mil paper barrier system, so there’s no other protection layer that’s built in. So the barrier ended up getting shredded by some of the onsite activities, which frankly are typical for any construction site. So, once again, that added time to make those repairs. And then finally, they use an inexperienced installer, which unfortunately just they didn’t have the knowledge to handle all the issues that kind of outlined above.

So when looking at the rest of the building, what worked well, MonoShield was just better suited for this application. MonoShield was able to be installed at on average 40 ,000 square feet per day, if not more. Because there’s a geotextile that’s bonded to the underside, it was able to hold up against a lot of the on-site activities. QAQC was much easier because all of that was handled by a certified installer who does this type of application on a daily basis. And so I just want to kind of wrap up this portion with this aerial shot of the vapor barrier installation. I think this photo does a really good job of showing, one, the scale of some of these warehouse buildings, and two, it shows how clean and efficient a system like MonoShield can be installed. And so kind of conclusions, takeaways, vapor barriers, when it comes to vapor and mitigation at new construction, it’s incredibly important. And vapor barriers are a common approach that are being used on a daily basis.

It’s important to remember to evaluate all factors that go into the vapor barrier selection. And number three there, the biggest threat to a successful vapor barrier installation are the onsite activities. So managing onsite activities can really help reduce some of the future liability. So that’s all I have. I’m going to pass this off to Eric. Thank you.

Good afternoon, and thank you all for joining us today to discuss the vapor intrusion, assessing vapor intrusion-related risk, and managing the vapor intrusion liability. Today, I’ll be giving a brief overview of vapor intrusion, taking a step back, and then follow that by discussion of how we typically evaluate, mitigate, and otherwise address vapor intrusion risks during transactions or for various commercial or industrial clients that we serve. We’ll be looking at vapor intrusion from the perspective of a property owner or prospective purchaser who may be wandering as a result of known or suspected site history, transaction related due diligence or some other triggering event, whether vapor intrusion is a concern for the facility in question. And if so, how to manage that associated risk.

We use our experience with these types of assessments to provide best practices for answering those types of questions, both in terms of limiting risk exposure potential and planning out for potential future costs for mitigation or remediation. So many of us here today probably have a pretty good experience with vapor intrusion but I suspect that there may be a number of you online that don’t have that background and we could always use a refresher for those of us that do. So to make sure we’re all working from a common starting point I’d like to run through a high level overview of vapor intrusion. So I’ll start with the question, what is vapor intrusion? US EPA website on vapor intrusion generally states right off that VI occurs when there is a migration of vapor forming chemicals from any subsurface source into an overlying building. Kind of bland.

So breaking that down a little bit, vapor intrusion begins with presence of contaminants in soil and or groundwater, which are sufficiently volatile to form vapors, which can then accumulate in soil gas. If that condition is met, then vapor intrusion may occur when the impact of soil gas moves under and accumulates beneath the structure and eventually migrates up and enters the structure through cracks or other imperfections in the foundation. If concentrations are high enough, once they get inside the building, the impacted indoor air may then represent health and safety risk for building occupants. The figure shown here is from the 2007 ITRC Vapor Intrusion Practical Guidance. Some of you are probably familiar with this. It provides a simple conceptual model of these conditions.

Again, a soil or groundwater contamination source at the bottom, emanating vapors which migrate upward through the zone, the unsaturated soil zone until it encounters the building where it then may enter the building. So there are numerous volatile organic compounds or VOCs which are potential concerns for vapor intrusion. Some of the more common VOCs identified at potential VI sites typically include the betex compounds listed in the first box here, found in gasoline and other petroleum based products and chlorinated solvents such as TCE and PCE which have been used extensively in industry as degreasing and dry cleaning solvents. There are also many other VOCs found in paint thinners, cleaners, solvents, fuels and other products that are used industrially and those can also represent a vapor protrusion concern but generally aren’t as commonly encountered as the BTECs and chlorinated solvents are.

So in addition to these VOCs, there are also a handful of other chemical types that may also be a vapor intrusion concern. Semi-volatile compounds like naphthalene, some pesticides, elemental mercury, and then even some PCB compounds, which may not seem like they’d be vapor intrusion risk, but even some PCBs can be. But again, these are much less common vapor intrusion contaminants compared to Vtex and chlorinated solvents. And that’s most of what we see in industry. Taking a step back, let’s use another visual aid or conceptual site model to take a look at the simplified process for vapors entering a building.

So first, there’s got to be the soil or groundwater source. So as shown in this USEPA diagram, soils contaminated with volatile organic compounds are depicted underground, also resulting in a plume of impact of groundwater. The source of this impact can be anything, a leaking underground storage tank, a surface spill that’s infiltrated into the subsurface, a leaking product line, industrial activity in general. So this source of contamination can then form vapors either directly from the soil source or from the dissolved groundwater source that’s moving away from that soil source. These vapors can then migrate with the soil gas through the soil. Various effects that you see indicated here can act like a pump that actually can draw contaminated soil gas towards and into buildings where it may accumulate beneath the building.

So the wind effect, the stack effect, soil moisture, preferential pathways, the silty layer shown here that may impede or force, you know, vapors into a direction that may not be anticipated. And then building foundations such as concrete placement floors or walls or concrete slab for without a basement, generally can’t act as a barrier to the soil gas or contaminated vapors entering a building. However, as we know, no foundation or floor is perfect. There’s going to be gaps between walls and floors, sumps and utility penetrations which aren’t properly sealed or where seals have failed, and then cracks or imperfections in the slab as the slab ages, those just get worse. So all of these imperfections may allow vapors to enter into the structure.

Once vapors have entered the building, they’ll mix with the indoor ambient air, which then may be inhaled by building occupants. It could be residential, commercial, industrial. Vapor intrusion can pretty much happen in any type of building. So should those concentrations be high enough in the indoor air, this can represent a real health concern, depending on the chemical concentration and exposure duration. Short-term effects at higher concentrations can lead to headaches and nausea, while longer-term exposures can lead to organ damage, typically liver, kidneys, lungs, or even cancers. So, so far, you know, it’s all doom and gloom, this sounds pretty serious, and vapor intrusion can be a significant issue with possible short-term and long-term health effects to expose populations. But we’ve not always given vapor intrusion a high priority.

So when did vapor intrusion really become a concern? recognition of contaminated soil gas related to VOCs or other compounds has been recognized as early as the 1980s. Those of you that have been around maybe as long as I have in this industry may remember using early soil gas sampling methods to actually investigate and delineate contaminated sites kind of in lieu of soil and groundwater samples. This practice was generally replaced in the mid to late 90s as discrete sampling methods for soil and groundwater approved and due to issues with relying on solar gas data to kind of investigate and delineate other media. A little bit of a disconnect there. So after the 90s, vapor intrusion was generally not considered a significant issue by many in the environmental consulting field and even at agencies until US EPA began considering the effects of vapor intrusion around 2000. And then US EPA eventually issued the Office of Solid Waste and Emergency Response, OSWR, draft guidance for evaluating the vapor intrusion to indoor air pathway from groundwater and soils. It’s a mouthful. That was issued in 2002, and I’ve included figure one at the bottom of this slide from that document.

Just to illustrate, even though that was issued in 2002, that conceptual model is still basically what we use to get our heads around vapor intrusion. So this draft Oxford guidance really did put the VI pathway back into the collective consciousness of environmental professionals and the regulated community. But in the early 2000s, VI was still often viewed as an emerging pathway like an emerging contaminant. They already knew it was going to be regulated at some point, but it was lightly touched and kind of ignored. This often led to potential vapor intrusion issues being downplayed or excluded from assessments and regulatory closures. So I’ll give you an example from my area in Illinois. The Vapor Intrusion Pathway wasn’t included into the Tiered Approach to Corrective Action Objectives, TACO, Voluntary Cleanup Framework until 2012. And the regulation wasn’t actually promulgated until 2013. So many sites that had already been enrolled in TACO program, you know, kind of scrambled to get their sites closed out in 2012 in early 2013 to kind of beat that effective date, which would have required vapor intrusion assessments.

After the draft Osward guidance was issued, there was obviously an increased awareness that various petroleum hydrocarbons, chlorinated solvents, other chemicals, and soil and groundwater posed a real but a different kind of threat via the indoor air inhalation pathway, contrary to established exposure pathways, so digging in impacted soil and direct contact or consumption of impacted groundwater to be exposed by the VI pathway, a receptor, so just a building occupant just needs to be inside and breathing, kind of a low bar to cross over compared to digging a hole or actively drinking contaminated water. With OSWR, wider recognition that vapor intrusion represented a different but significant threat. Different additional guidance was published by ITRC, ASTM, and various states in the mid-2010s, and then EPA finally finalized OSWR in 2015.

Well, it was finalized in 2015 at the state level, the regulatory framework to assess of intrusion was and unfortunately still is kind of a patchwork of varying regulations. Many states do have robust kind of standalone VI assessment programs and others rely on the federal guidance and still others consider VI only on a case-by-case basis, so lightly regulated. And then finally with the ever-expanding knowledge base, VI guidance, both state and federal, continues to evolve. We’ve seen somewhat recently the issue with trichloroethylene, TCE, new exposure criteria cause the EPA to issue some much lower screening criteria for TCE than originally had been released, and that’s caused some issues with sites that may have been already closed.

So, environmental consultants occasionally have the job of educating a client on the nature of risk that vapor intrusion can represent. So, presented here are some readily understandable reasons, I think, why vapor intrusion should be evaluated if there’s really any potential for a VI concern identified at site. First off, between work, home, general life, we spend most of our time in sites. This means there’s a lot of potential receptors for vapor intrusion walking around. For industrial commercial sites, this means workers or other occupants could be exposed to vapor intrusion over the course of a normal workday, and then a week, month, and a year. So maybe transitory exposures for visitors or customers to sites as well. Exposure to residential sites is a little bit more straightforward. Much more time is likely to be spent indoors at home than at work or commercial industrial buildings.

As briefly discussed previously on the conceptual site model slide, vapor forming contaminants in the subsurface tend to migrate toward buildings. So if there’s a known or suspected vapor intrusion source at or near your site, it can reasonably be expected to maybe migrate towards your building. So another reason that you might wanna do one of these assessments. And speaking of sources, there are myriads of potential sources of VOC contaminants in the soil and groundwater scattered across the town. Even small towns likely have some property that represents or represented a potential source for VI, whether it’s an industrial commercial or municipal facility, like a municipal facility with fuel storage tanks at a vehicle garage, a small dry cleaner, and of course, local gas stations are just about everywhere or your local auto repair.

Also recall that sites that were closed, as I mentioned, before the 2010s or the mid 2010s may have received regulatory closure without evaluating the intrusion. And a significant subset of those sites, the closures included management of residual soil or groundwater impacts in place under risk-based approaches. But again, that may not have included a vacant intrusion evaluation. In addition to these closed, but still potential VI source properties, kind of the same thing happened with the leaking underground storage tank closures. A lot of those were closed out with some residual impacts in place in soil and groundwater, but the VI pathway was not assessed. And then finally, we need to consider who’s asking the questions about vapor intrusion at any given site. Are we dealing with a property or a business transaction where the potential for a vapor intrusion has been identified during due diligence?

The potential buyer, as well as any investors or lenders that may be involved in this scenario, you know, will likely want an answer to the vapor intrusion question. In this case, an expedited VI evaluation may be required, but may not be able to be completed by the time a deal is closed. Vapor intrusion concerns may also be driven by facility or portfolio managers who want to keep ahead of changing regulations. Better to address a potential issue now, so it’s not a costly surprise later. Legal counsel for a potential deal, are usually knowledgeable about vapor intrusion and can help pave the way to getting VI assessments completed and keep a deal moving forward. And then investors and lenders who may have collateral interests in a property may require assurances that vapor intrusion has been or will be evaluated, protect the value of the asset going forward.

Insurance companies likewise are underwriting environmental liability insurance policies desirable by the buyer in a transaction to limit their overall liability, but that insurance company would be a helpful driver for VI assessments because they want as much information as possible when they’re writing a policy. So due to the nature of investors, lenders, and insurance, these interested parties are usually quite conservative. And then, finally, last but not least is government agencies may also drive paper intrusion assessments as part of voluntary projects or compulsory, or as follow-ups to previous work. As I mentioned, there’s been some changes or lowering in the screening criteria for trichloroethylene, TCE. Some states have looked at going back and reopening or re-looking at sites where TCE might have been an issue.

So I’ll summarize real quickly. The common thread for all of these interested parties are the potential liabilities associated with vapor intrusion. Initial liability may be the cost of evaluating or assessing vapor intrusion. Third-party liability is also a concern for VI exposure or injury to employees or other persons who occupy an affected building. The prospect of third-party liability, which may include damages, is often a strong motivating back to address vapor intrusion from interested parties. Known or suspected VI that has not been addressed can negatively affect properties or a business’s valuation. And then also known or suspected vapor intrusion that hasn’t been addressed may not only affect that valuation, but also represents a potential capital cost for assessment and mitigation in the future should somebody want to come in and buy it.

And then of course, on top of that, more third party liability for anybody that’s been exposed in that interim time framework was not addressed. I just included a little picture there in the inset showing some sub slab sampling using a vapor pen. And in this case, I think we’re purging the vapor pen before sampling with a similar can. So after all that, I wouldn’t blame anyone for suggesting that just get out to the site already, collect some samples and determine if we have vapor intrusion. Again, before we do that, we need to determine if there’s a reasonable potential for there to be a VI concern and identify what we want to be looking at. As many vapor intrusion assessments are completed in the course of environmental due diligence related to transactions, phase one can provide information on current or historical operations at a site that may be of interest, dry cleaning, manufacturing, painting, plating operations, anything that may have used vapor forming chemicals historically or currently.

Based on the information gathered from a phase one, an environmental professional will make a determination whether there’s been a release, recognizing environmental condition or a wreck, and this determination of a wreck with respect to vapor intrusion may be based on known impacts, if there’s existing data, or based on site use and history. For vapor intrusion, this evaluation may also include offsite areas where volatile contaminants are known or suspected to be present in the subsurface as vapors from offsite sources can migrate and do migrate and impact other sites. So that said, if there’s a suspected or known release of volatile chemicals at or near a subject site, VI assessment is warranted. So, the next step is a vapor intrusion assessment, part of a broader site investigation, including soil and groundwater assessment as well, but more and more clients that we serve are encountering sites where standalone vapor intrusion assessments are requested and actually appropriate.

These types of sites include things that we’ve talked about previously, facilities with existing data on soil and groundwater conditions, maybe with a regulatory closure already, but no vapor intrusion assessment. We see that very commonly nowadays. Maybe an old UST was closed or another release was closed before the vapor intrusion regulations were promulgated. We also see facilities with limited access for soil and groundwater sampling, but the client is still concerned that there could be a vapor intrusion risk. And again, that third party liability where, you know, the risk that they might be exposing their workers or occupants in the building is a significant driver, so they want to, even though they might not be able to do a soil or groundwater phase two, they can probably still do a vapor intrusion assessment.

There’s also facilities that may be contractually restricted from sampling, so think of somebody leasing a property and their lease basically has a, you know, a no look or a no dig clause And we’ve seen those in sites that have been sold with those kind of stipulations. And then facilities where the identified risk, the identified potential, the protrusion risk is related to migration from offsite sources. So you might not need to look at what’s going on in the soil or groundwater at the site. You might just be interested in what vapors are coming from that offsite source. So there’s numerous tools available for environmental consultants to use when designing a vapor intrusion assessment, but first remember the generic conceptual site model and modify it to fit your site, then plan out your sampling strategy accordingly.

Soil gas samples as either a soil gas at depth or sub-site samples under a building, depending on applicable guidance, are usually my preferred sample media for initial screening. These samples represent a direct measurement of the media that may affect indoor air in a building, so you don’t need to do much manipulation to kind of assess that data. Groundwater samples may also be useful in assessing vapor diffusion risks, particularly in situations where plume of impacted groundwater is migrating beneath the building far from the soil source, so I can give you an idea of how much mass there might be in the groundwater that can then volatilize. However, assumptions have to be made regarding that volatilization and how those vapors are going to move through the capillary fringe and then into the cavito zone.

So, even though we do often look at groundwater samples, we usually augment those or supplement them with soil gas or sub-slab samples as well. Indoor air samples are typically only recommended when collected in conjunction with soil gas or subslabs, soil gas samples, just due to the likelihood of false positive results in the indoor air samples related to chemicals used or stored at the site, or even ambient air sources around the subject site, nearby gas stations or industrial facilities that may be emitting the same VOCs that are being investigated at the site. In some cases, our indoor air samples may either be required by guidance or they may the only type of sampling possible. Again, based on sampling restrictions. So in those cases, careful sampling design, collecting upwind background samples, preparation prior to collecting samples, identifying and eliminating potential products that will interfere with sampling. It’s all critical to minimize those background interferences.

Soil samples, it’s always tough. You have to do a lot of manipulation of soil data to kind of get to what may be vaporizing off soil. It’s good to know. I mean, if you know you have really hot soils with a lot of benzene or TCE in it, it’s a good chance there could be a vapor intrusion concern, but you’ll still want to grab some soil gas samples to kind of confirm that. So when designing your vapor intrusion assessment, it’s critical to identify what screening criteria you want to use before you order your sample cans and hit the field. Make sure you know of the applicable criteria and that your copy of any guidance that you’re using or criteria are up to date. Work with your contracted laboratory to ensure they also know what criteria you’re going to be looking at so that they can meet those reporting limits.

The second bullet down here goes to the OSWARE guidance and it is really good. The 2015 OSWARE guidance does recommend using multiple lines of evidence approach to support conclusions in a VI assessment, including not only looking at the reported analyte concentrations, but also whether the site geology is likely to permit or impede soil gas migration. Is it really sandy or is it really clay? Depth too and the condition of groundwater is important. Is the groundwater super deep or is it shallow? Does it have a lot of dissolved contaminant or a little. These things can affect whether they’re actually going to be a vapor intrusion, so potential vapor intrusion source. And then the building configuration too. Is it near the source? Is it far away? New or old construction? And what is the condition of the foundation or system?

All right, well hopefully I didn’t lose too many of you during that overview in air quotes of vapor intrusion and vapor intrusion assessments. But now we can get to the part where we’re actually talking about maybe identifying and managing risk. And I think the best way to do that is to run through an example. So this was an interesting site that we pretty recently dealt with. It’s a commercial site in California. It’s actually about a 10 acre campground. It’s got a couple clubhouse buildings and pool buildings, some permanent structures, but mostly it’s an open RV type campground. History doesn’t suggest anything other than commercial recreational use. However, as we said before, a good phase one can tell you a lot. And in this case, the phase one that was completed as part of the transaction due diligence identified a former car dealership that had a leaking underground storage tank that was closed, but again, without a vapor intrusion assessment that was almost adjacent, and then a former metal fabrication facility that had a known chlorinated solvent, groundwater plume, emanating from that off-site facility.

It was a little bit farther away, four or 500 feet. But both these facilities were pretty near the site. Luckily, this site was in California, and our geologists were able to download and review you know, numerous reports for both of these facilities. And we determined that the closed out leaking underground storage tank may not have been that big of a deal, but we determined that the chlorinated solvent impacted groundwater had likely already migrated beneath the site and past the site and could therefore be a site for vapor intrusion in the limited number of permanent structures that are at the campground. So therefore we did recommend a vapor intrusion assessment. And this evaluation included a collection of some subslab soil gas samples, co-located indoor air samples. That’s kind of the three pictures on the left.

See the installation of a vapor pen to collect subslab soil gas, a sumacan sitting up kind of in the near breathing zone, and then the vapor pen being sampled in the other picture there. And then also, because we did do some indoor air sampling there, We did do ambient background samples, upwind, downwind, just to make sure we had everything covered. Ultimately, the soil gas and indoor air results at the site didn’t indicate active vapor intrusion at the site. However, that’s not quite the end of the story because chlorinated solvent compounds were detected at low levels in the subslap soil gas below the applicable criteria, but they were present. So short term, you know, we’ve managed the risk by investigating the vapor intrusion and determining that the VI pathway is not complete at the time of the sample. So this information was sufficient to get the deal closed, but again, we’re not quite done with our assessment yet.

The off-site chlorinated solvent source and that resulting groundwater plume is unlikely to be remediated in the near term to a point where it’s no longer a vapor intrusion threat. So to continue to manage the vapor intrusion risk at this site, seasonal vapor intrusion monitoring will be completed going forward, as well as the review of the remediation document for the solvent impact source to track groundwater conditions and remediation progress. In addition, conceptual plan for vapor intrusion mitigation was completed and roughly costed out so that the facility owner has that information and can plan for potential liabilities and costs should vapor intrusion become an issue in the future and mitigation is required. They won’t have a shock to the system with a big cost that they weren’t expecting. And then of course, you know that the vapor intrusion monitoring will probably go on for some time.

As I stated previously, as buildings age, they settle and foundations crack, making them more susceptible to vapor intrusion and that groundwater plume is going to continue to migrate if the concentrations in that plume increase. Maybe we do see sub slab concentrations that are a concern and maybe we have to move to mitigation. So summarizing for this example, risk management at this facility included you know, a thorough due diligence investigation which identified the potential vapor intrusion issue. And again, no on-site issue, nothing at the fault of the operations or history of the site, strictly related to an off-site contamination. An active VI assessment was completed to evaluate if vapor intrusion was occurring at the site. It wasn’t.

Going forward, there’ll be additional monitoring to confirm those results and ensure that VI risk can be quickly addressed should conditions change in the future. And again, we’re dealing with a potential TCE or an exaltance. So there can be low threshold to force action in this case. So monitoring will be important going forward and estimating projected costs for mitigation now so that if it becomes necessary in the future, they can be planned for now rather than having to scramble in the future. So just a quick note when considering vapor intrusion mitigation. It is important to remember that mitigation usually does not equal remediation whether it be a soil source on site or a migrating groundwater plume from off site as in this case the underlying source responsible for the impact of soil gas is still present and you know even if the vapor intrusion mitigation is implemented.

So in these situations, managing risk means planning for perpetuity, or at least until the underlying sources are mediated. In this case, planning for perpetuity means regular VI screening at the site, which could eventually lead to mitigation, and then additional monitoring once mitigation is installed to ensure that it is performing as required. I think I’m running a little long here. So I have another case study for an Illinois redevelopment site, and I’ll try to cut it a little short. About a 10-acre vacant former commercial industrial site in the Chicago area, again, due diligence identified historical use of the site as potential concerns, onsite there was printing, large-scale printing operation offsite, there was an adjacent dry cleaner and an adjacent leaking underground storage tank bracketing the site. Because this is going to be a local home builder acquiring this vacant, now vacant property to construct townhome development, that buyer, that developer is going to need a clean closure to facilitate sales of residential units.

So you get that clean closure in Illinois from our voluntary site remediation program, the SRP, which, you know, again, as I mentioned earlier, the vapor intrusion pathway was added to the rules governing the SRP in 2013. So to get that comprehensive, no further remediation letter through the SRP, we’re going to have to look at soil, soil gas, and groundwater at this site to get it closed out. So we did that, we identified some minor soil and groundwater issues. Soils, some lightly impacted soils with metals were excavated and removed. Groundwater, I think was okay at this site. And then there was one small area that had a low TCE hit in the soil gas. So in that affected area, we’re likely going to need to install some sort of mitigation. And since it’s going to be new construction, it makes it easy to do.

The approved building control technologies under the SRP program would likely require some sort of a vapor barrier, vapor membrane, and that overlaying by some inches, you know, some inches number of concrete, which is escaping me right now, how much that is. So everything on this site will be slab-on graded with a vapor barrier to mitigate that potential vapor intrusion risk from the TCE that was identified in one small area at a very low level of the site. So the reason I wanted to include this case study and kind of give you the high level on it is the takeaway points is VI mitigation, especially if you’re dealing with new construction, doesn’t have to be complicated and probably won’t be that expensive. It can be rolled into the cost of redevelopment at some small increase.

But the more important thing here is if you can get closure through a state program, especially when you’re considering VI, this may help insulate you from regulatory changes in the future. In Illinois, the agency has pretty strongly come out and said that they really won’t reopen a site unless they have site-specific information that’ll cause them to want to re-look at a site. So it’s unlikely to be, less likely to reopen if you have a formal closure from the agency. So, and that just goes back to the changes to the TCE screening levels that may cause some heartburn for sites in other states, Michigan and Wisconsin and others are actually looking at old sites that were closed that had TCE contamination and looking at maybe re-opening or re-looking at those to make sure that the vapor intrusion isn’t an issue.

So to summarize, vapor intrusion risk is a liability that is more likely to require an active response due to the unique exposure pathway and wide range of receptors may be affected. When suspected or known, the intrusion risks are identified at a site, liability can be managed through well-established assessment and mitigation options. Therefore, to complete liability management on an accelerated basis, as often necessitated by transactions, just follow a pragmatic approach. Analyze the vapor intrusion liabilities to quickly identify and quantify those risks and the consequences that VA vapor intrusion may present on any given transaction or facility. VI-risk to the exposed population facility personnel or the public is usually the driving factor.

Again, that’s the third party liability for injury. Identify your risk and mitigate it quickly. Given these factors, vapor intrusion liability estimates can be generated to not only guide the transaction process, but to expediently manage liability post-close and into the future. Thank you for joining us today, and that’s all I got.