Have You Caught a Case of the Vapors?

Have You Caught a Case of the Vapors? By: Staige Miller, EP, Director of Environmental Services March 2012 Why is Vapor Intrusion an Environmental Risk? There is a new buzz word that is making its way into the scope of Phase I Environmental Site Assessments (ESAs). Many of you have been hearing about vapor intrusion over the last few years as it has been gaining more media publicity and government attention. Part of the additional scrutiny is due to the 2010 ASTM publication of E 2600-10, Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions. This supersedes the former ASTM E 2600-08, Standard Practice for Assessment of Vapor Intrusion into Structures on Property Involved in Real Estate Transactions published in March of 2008. The new standard targets screening for the likelihood of chemicals of concern (COC) that may migrate in the subsurface as vapors onto a property as a result of contaminated soil and groundwater on or near the property resulting in a vapor encroachment condition (VEC). 1 The standard does not specifically address whether the migrating vapors that create a VEC will cause a vapor intrusion issue into a building on a property, which may ultimately lead to an indoor air quality problem. The difference between a VEC and vapor intrusion is quite simple: a VEC is just the presence or likely presence of COC vapors in the subsurface of the property caused by a release of vapors on or near the property; whereas, vapor intrusion refers to the actual migration of volatile vapors into overlying structures. The figure above depicts the migration of volatile chemicals from contaminated soil and groundwater plumes into buildings. Volatile chemicals are shown to enter buildings through cracks in the foundation and openings for utility lines (preferential pathways). Atmospheric conditions and building ventilation are shown to influence vapor intrusion. 2 At this point, you should be asking yourself why all of this is important. Well, it is expected that the Tier 1 vapor encroachment screen (VES) under ASTM E 2600-10 will become a standard inclusion in an All Appropriate Inquiry (AAI)-compliant Phase I ESA. According to Anthony J. Buonicore, P.E., and Chairman of the ASTM Vapor Intrusion Task Group, Vapor migration under the Comprehensive Environmental Response Compensation and Liability Act (CERCLA) and AAI must be treated no differently than contaminated groundwater migration in Phase I ESAs. Moreover, there are good business reasons to conduct a VES, including avoiding potential investigation costs in the future, avoiding liability, such as potential litigation that may arise from tenant or other third party lawsuits, and avoiding property devaluation. A number of government agencies, most notably, the U.S. Department of Housing and Urban Development (HUD), as well as lenders and commercial real estate attorneys are already requiring the consideration of vapor encroachment as part of Phase I ESAs. Vapors have the ability to harm human health, even in low concentrations. Based on rising concerns and risks associated with vapor intrusion, HUD began requiring a vapor intrusion screen under the

previously issued Multifamily Accelerated Processing (MAP) Guide dated December 1, 2009. This has been substantiated in the most recently issued MAP Guide revised dated November 30, 2011; which indicates in Section 9.3.j, The Phase I ESA must include an initial vapor (a.k.a. gas) encroachment screen to determine if there is a potential for vapors to occur in the subsurface below existing and/or proposed on-site structures The initial vapor encroachment screen amendment to the Phase I ESA shall be performed using Tier 1 non-invasive screening pursuant to ASTM E 2600-10. 3 Vapor migration/intrusion is becoming an increasing concern for other government agencies. 32 states have adopted guidance for vapor intrusion and the U.S. Environmental Protection Agency (EPA) has opened a public comment period on a proposal to add a new screening mechanism to the Hazard Ranking System (HRS) that would enable sites with vapor intrusion contamination to be evaluated for placement on the National Priorities List (Superfund List). 4 HUD is the first federal agency to begin requiring a Tier 1 VES as part of a Phase I ESA as outlined in their Chapter 9, Environmental Review and Requirements of the MAP Guide. D3G has performed over 2,000 Tier 1 VES s to date since the inclusion of this scope of work into our Phase I ESAs as part of D3G s standard operating procedures, with this number continuing to climb rapidly. D3G includes a Tier 1 VES as part of all Phase I ESAs in order to conform with the HUD MAP Guide, as well as ASTM E 1527-05 (Standard Practice for Environmental Site Assessments: Phase I ESA Process) and AAI. Performing a Tier 1 VES and Subsequent Steps To complete a Tier 1 VES, the following minimum information is required, all of which are reviewed as part of the completion of an AAI-compliant Phase I ESA: existing/planned use of the subject property; type of structures existing or planned on the subject property; surrounding area description, federal, state, local and tribal government records on the subject property and for the area of concern (AOC); historical records related to prior use of the subject property and surrounding properties within the AOC; general physical setting information; significant natural or man-made conduits that can serve as preferential pathways for the migration of vapors; and User-specialized knowledge, experience and commonly known or reasonably ascertainable information related to the subject property and the area within the AOC. 5 The ASTM Standard provides a two-tiered methodology to evaluate the potential for a VEC to exist. The first tier focuses on whether known or suspected properties with sources of contamination exist within the AOC around the subject property. If the Tier 1 VES determines that there are properties of known or suspected contamination within the AOC, then the work proceeds to a Tier 2 to further define the presence of a VEC. A Tier 2 screening involves a more detailed analysis of readily available information as it relates to data already collected for the release (soil, soil gas and/or groundwater testing results). This data is either garnished from a Freedom of Information Act (FOIA) request of files from the state environmental agency or, if no data is available, then an invasive study may be performed to include sampling of soil, soil gas, and/or groundwater on the subject property, at the subject property boundary or off-site. In addition, if on-site contamination is identified in the file review or off-site contamination is suspected to migrate onto the subject property, then an invasive study as discussed above may also be required. Below are some scenarios to help guide you through the process of determining what happens after a VEC is identified in the Tier 1 VES and/or Tier 2 screening:

Scenario A Leaking Underground Storage Tank (LUST) was identified adjacent and up-gradient to the subject property in the Tier 1 VES, what next? The first step should be to submit a FOIA request to the state environmental agency for files in order to review work that has already been completed at the property to further evaluate the presence of a VEC. Once files are received, several items should be considered such as: was the contamination limited to soil; was groundwater impacted; confirmation of the groundwater flow direction; levels of any identified contamination; remedial activities performed, etc. Performing a file review with the state environmental agency is considered to be a Tier 2 noninvasive vapor encroachment screen as indicated in the ASTM E 2600-10 Standard. A.) Only petroleum-contaminated soil was identified in a review of the files for the adjacent and up-gradient LUST incident. No free product was observed. In this case, the identified contamination needs to be located at least 30 feet away from the subject property boundaries. If the contamination is located greater than the specified 30 feet from the subject property, then no further investigations are warranted and a VEC does not exist or is not likely to exist at the subject property. B.) The file revealed contaminated groundwater associated with the adjacent and upgradient LUST incident. At this point, a more thorough review of the groundwater data should occur. For example, the location of the sampled groundwater monitoring wells requires you to ask some questions including: is there a contaminated groundwater plume identified; what were the identified contaminants; what direction is groundwater flow and what were the levels identified and were they above the state action levels? For the purposes of this scenario, let s assume that the groundwater monitoring wells closest to the subject property boundaries did not indicate the presence of contaminants above laboratory detection levels; whereas, wells located further away identified the presence of contaminants above the state action levels. In this scenario, a remedial plan has been implemented and the contamination is under control and is no longer migrating. Based on the fact that the wells located closest to the subject property did not identify contaminants as being above the state action levels and the contamination is no longer migrating towards the subject property, no further recommendations are warranted and a VEC does not exist or is not likely to exist at the subject property. C.) The file revealed contaminated groundwater associated with the adjacent and upgradient LUST incident within close proximity to the subject property boundaries. For the purposes of this scenario, let s assume that the groundwater monitoring wells closest to the subject property did indicate contaminants above the state action levels. The wells were located along the subject property boundary but no monitoring wells had been installed on the subject property to determine if contaminants had migrated onto the subject property. In this example, the recommendation would be made to first conduct a Tier 2 invasive screening, which would include the collection of soil and groundwater samples to further evaluate the presence of a VEC and to determine if contamination has migrated onto the subject property that presents a recognized environmental condition (REC). A REC is defined in ASTM E 1527-05 as the presence or likely presence of any hazardous substances or petroleum products on a

property under conditions that indicate an existing release, a past release, or a material threat of a release of any hazardous substances or petroleum products into structures on the property or into the ground, groundwater, or surface water of the property. 6 At this point in the process, it is not acceptable to only conduct indoor air sampling within the subject property structures as the results will not conclusively indicate whether groundwater contamination is present on the subject property constituting a REC at the subject property, nor will it provide the necessary documentation to indicate that a VEC does not exist or is not likely to exist on the subject property. Indoor air sampling will only indicate the conditions inside the building and will not reflect subsurface conditions. In order to comply with the ASTM E 1527-05 Standard, the Environmental Professional will need to determine if the adjacent and up-gradient LUST incident presents a REC at the subject property. D.) The results of the Tier 2 invasive screening indicate the presence of contaminants on the subject property. The results of the Tier 2 invasive screening (soil and groundwater sampling) indicate the presence of contaminants above the state action levels, which constitutes a REC. At this point, a VEC cannot be ruled out at the subject property. In addition, the elevated levels were identified within close proximity to the subject property structure. Based on the close proximity of the identified contamination, additional Tier 2 data will need to be collected at the subject property to further evaluate whether vapor intrusion into the subject property structure is occurring. A vapor intrusion assessment will need to be conducted in accordance with either the state and/or EPA vapor intrusion guidance documents. If vapor intrusion is determined to be occurring into the subject property structure, then mitigation may be warranted. Conclusion As stated previously, D3G has performed over 2,000 Tier 1 VES s to date as part of our Phase I ESAs and at no additional cost to our clients. D3G also has the capability to perform file reviews (aka a Tier 2 non-invasive screening) and Limited Phase II ESAs, including soil and groundwater sampling, as well as soil gas sampling (aka Tier 2 invasive screening). So the bottom line is that you are in good hands if you chose D3G as your Phase I ESA provider! We have the experience and knowledge to get your project to the finish line.

References 1. Buonicore, A. (2010, June 17). New ASTM Standard on Vapor Encroachment Screening Published. [Web log post]. Retrieved from http://commonground.edrnet.com/posts/b6a247b19. 2. The 2008 Brownfields Technology Primer: Vapor Intrusion Considerations for Redevelopment; EPA 542-R-08-001: Washington, DC, 2008. 3. Multifamily Accelerated Processing Guide, Chapter 9, Environment Review and Requirements; United States Department of Housing and Urban Development: Washington, DC, 2011. 4. Vapor Intrusion and the Superfund Program accessed on March 15, 2012 at http://www.epa.gov/superfund/sites/npl/hrsaddition.htm. 5. ASTM E 2600-10, Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions; ASTM: West Conshohocken, PA, 2010. 6. ASTM E 1527-05, Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process; ASTM: West Conshohocken, PA, 2005.