em feature by Anthony Buonicore Vapor Encroachment Screening Under the Newly-Revised ASTM E 2600-10 Standard Anthony J. Buonicore, P.E., DEE, QEP, is chief executive officer of The Buonicore Group, and Chair of the ASTM Vapor Intrusion Task Group. E-mail: ajb@edrnet.com. Vapor migration and intrusion into structures on a property can potentially create significant liability and have a material impact on property value. As such, it is a growing concern for property owners, prospective purchasers of property, and environmental professionals conducting due diligence. 1,2 To respond to this industry concern, in June 2010 ASTM published E 2600-10, Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions. 3 Rationale for Revising the Standard The original ASTM E 2600-08 standard was published in March 2008. After more than a year in the marketplace, it became clear that the standard created a considerable amount of confusion. For example, there was confusion over whether the standard was a vapor intrusion assessment standard or a vapor intrusion screening standard. There was confusion over the standard s relationship with the ASTM E 1527 Phase I environmental site assessment 4 standard. There was confusion as to why, if there was insufficient data to rule out a potential vapor intrusion condition, it was presumed to exist. The standard also found considerable resistance in the legal community, where it was believed the standard may have overstepped its bounds and drew legal conclusions in direct contradiction to Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the U.S. Environmental Protection Agency s (EPA) All Appropriate Inquiries (AAI) regulation. Unfortunately, this confusion in the marketplace had a detrimental impact on the standard s adoptability and necessitated revisions be made. Revisions To resolve the confusion, substantial revisions were made and balloted in March and April 2010. The result was a revised standard, E 2600-10, published by ASTM in June 2010. 3 The revised standard is refocused solely on screening for the likelihood of volatile vapors to encroach upon or otherwise reach the subsurface of a property involved in a real estate transaction (thereby, creating a Vapor Encroachment Condition or VEC). The title of the standard was also changed to better reflect this approach. In addition, the revised standard was issued as a standard guide, rather than a standard practice, to give the environmental professional conducting the vapor migration screening greater latitude, particularly in view of the considerable uncertainty that still exists in vapor migration assessment. This guidance approach has been used by EPA, the U.S. Department of Defense, and virtually all government agencies that have addressed vapor intrusion. The presumption that a VEC exists if there is insufficient data to rule it out no longer exists. Finally, a new legal appendix was included to clarify the relationship with the ASTM E 1527-05 Phase I standard, CERCLA, and AAI. Experience to date suggests the newly revised standard has eliminated much of the confusion and resulted in its adoption much more readily by government agencies, lenders, and prospective purchasers of real estate. Tier 1 Screening Under E-2600-10 The only significant difference between Tier 1 screening in the revised standard as compared to the methodology in the previous E 2600-08 standard is that the secondary area of concern (AOC) was eliminated in E 2600-10. This was done because experience had demonstrated that including the secondary AOC wasted time and money investigating contaminated sites much too 4 em february 2011 awma.org
Vapor migration onto a property involved in a real estate transaction needs to be evaluated in a Phase I investigation, no different than groundwater migration. awma.org february 2011 em 5
far from the target property and which were unlikely to impact it from a vapor migration/intrusion viewpoint. The information required for Tier 1 screening in E 2600-10 is essentially the same information collected as part of an ASTM E 1527-05 Phase I. The first check in the screening process is a search distance test to identify if there are any known or suspect contaminated sites with volatile or semivolatile hazardous substances or petroleum products, referred to as chemicals of concern (COC), within the AOC. If there are none, no further action is required. Search distances are different for sites contaminated with [non-petroleum hydrocarbon] COC, such as chlorinated volatile organics, versus sites contaminated with petroleum hydrocarbon COC. Search distances are shorter for the latter because they are known to undergo significant biodegradation in the presence of oxygen. To identify the AOC for contaminated sites with [non-petroleum hydrocarbon] COC, the search radius is 1,760 feet (1/3 mile) from the contaminated site to the boundary of the target property (TP). For sites with petroleum hydrocarbon COC, the search distance is 528 feet (1/10 mile). The AOC search distances were determined based upon conservative consideration of both contaminated plume lengths and the distances vapors volatilized from contaminated plumes might travel along a path of least resistance in relatively permeable soil from a source through the vadose zone directly to a TP. If groundwater flow direction can be estimated, the AOC in the cross-gradient and down-gradient distances can be reduced significantly. If a known (or suspect) contaminated site with COC is located in the AOC, the environmental professional may then apply judgment with respect to deciding whether or not this site represents a VEC. For example, if there is a hydraulic or physical barrier (such as a river) between the TP and the contaminated site, the presence of such a barrier would likely impede any migrating contaminant vapors. The environmental professional may also not be concerned about migrating vapors based upon experience with local subsurface geology and soil characteristics. The possible existence of significant man-made or natural preferential vapor pathways between the contaminated site and the TP must also be evaluated. Natural preferential pathways may include, for example, fractured bedrock or karst terrain. Man-made pathways may include, for example, major utility corridors or sewer lines. If such significant preferential pathways do exist, then proceeding directly to invasive sampling (e.g., soil gas sampling) under Tier 2 may be necessary to determine if vapors have impacted the TP. The location of the contaminated site relative to the TP is also important in the screening. If the contaminated site is located up-gradient of the TP, there is much greater concern than if it is located down-gradient or cross-gradient. To understand why, it is necessary to understand the definition of critical distance (CD) in the standard. Effectively, the critical distance is the upper distance a vapor may migrate through soil in the vadose zone assuming the path of least resistance is directly from the nearest edge of the contaminated media such as groundwater or soil to the nearest boundary of the TP. The standard specifies a CD for both [nonpetroleum hydrocarbon] COC and petroleum hydrocarbon COC. For [non-petroleum hydrocarbon] COC, the CD is 100 feet. For petroleum hydrocarbon COC, CDs are specified for both light non-aqueous phase liquids (LNAPL; i.e., free product that can accumulate on the water table) and dissolved petroleum hydrocarbon situations. The CD for dissolved petroleum hydrocarbon COC is 30 feet. The CD for petroleum hydrocarbon COC vapors from LNAPL is the same as for [nonpetroleum hydrocarbon] COC (i.e., 100 feet). If a contaminated site is located down-gradient from the TP, it generally can be eliminated from concern if it is beyond the CD. If the contaminated site is cross-gradient, it generally can be eliminated from concern if it is beyond the CD plus an additional distance that can approximately account for the width of the plume. A conservative methodology for estimating plume width for use in this standard has been presented. 5,6 The conclusion from Tier 1 screening is that a VEC exists, is likely to exist or cannot be ruled out, or 6 em february 2011 awma.org
Everything you know about Clean Air Act permitting is about to change. Don t worry. We ll point you in the right direction. Changes are coming to NAAQS, NSR, PM 2.5, and Ozone regulations. New Greenhouse Gas Tailoring rules are about to kick in. Pretty soon, you ll be needing a lot of new information. The Air & Waste Management Association has you covered with a series of workshops focused on what you need to know, not just about permitting changes, but about their local and regional impacts. The Understanding Today s Clean Air Act Permit Programs 2011 Workshop Series TitleV 8 hr. Ozone Standard PM 2.5 NSR View draft agenda and register now! March 1-2, 2011, InterContinental New Orleans Hotel, New Orleans, LA Mark your calendar, more information coming soon! April 13-14, 2011, Houston, TX May 4-5, 2011, Denver, CO Researching and studying so many changes at once would be a full time job. That s why we re doing it for you. www.awma.org/events CATR Greenhouse Gas Tailoring that it can be ruled out because it does not exist or is unlikely to exist. If a VEC exists, is likely to exist, or cannot be ruled out, the client and the environmental professional must decide if further investigation, such as proceeding to Tier 2, is warranted. A user may, for example, decide alternatively to proceed preemptively to mitigation. Tier 2 Screening Under E 2600-10 The only significant difference between Tier 2 screening in the revised standard as compared to the methodology in the previous E 2600-08 standard is that the risk-based concentration test was eliminated. In this test, the concentration of the COC in the contaminated media (e.g., groundwater) is compared to the state (or federal) risk screening levels (RSLs) developed for this media. The riskbased concentration test was not included in Tier 2 of E 2600-10 because this test goes beyond screening (which is the sole purpose of the revised standard) and is better associated with an actual vapor intrusion assessment investigation. Tier 2 screening under E 2600-10 consists of either a noninvasive or an invasive investigation, depending upon the availability of contaminated plume data associated with the contaminated site creating the VEC identified in Tier 1. If contaminated plume data is available in state regulatory files or elsewhere that can provide insight into the extent of contamination associated with a contaminated property, the extent of plume migration, plume characteristics, and the status of any remediation, then the noninvasive screening methodology involves assessing whether the contaminated plume edge nearest the boundary of the TP is within or outside the CD. If no information on the contaminated plume and its characteristics is available (or if there are preferential vapor pathways), then it may be appropriate to evaluate whether or not invasive sampling (e.g., soil gas and/or groundwater sampling) at the TP boundary would be a viable option. If sampling is conducted, the results may be used to determine if a VEC exists or that it can be ruled out because it does not or is unlikely to exist. If a VEC exists or is likely to exist or cannot be ruled out after the Tier 1 and Tier 2 screening, the awma.org february 2011 em 7
The newly revised standard has eliminated much of the confusion. client and environmental professional must decide on what further investigation, if any, is appropriate. Such further investigation is beyond the scope of E 2600-10. Consultants may, for example, recommend proceeding to a vapor intrusion assessment investigation following the state s vapor intrusion guidance document or policy, assuming one exists, or recommend proceeding preemptively to mitigation, which may be more cost effective. Alternately, the client may decide to proceed no further with the deal. Relationship Between E 1527-05 and E 2600-10 The Legal Appendix of E 2600-10 clarified that vapor migration onto a property involved in a real estate transaction needs to be evaluated in a Phase I investigation, no different than groundwater migration. Tier 1 screening in the E 2600-10 standard provides an industry consensus methodology that can accomplish this. If vapor migration screening using E 2600-10 is conducted in conjunction with an E 1527-05 Phase I and a VEC is found to exist or is likely, then the environmental professional will also need to determine if the VEC represents a recognized environmental condition (REC). VECs will not automatically result in a REC. For example, if the depth to contaminated groundwater or the distance between the edge of a contaminated plume and the nearest structure on the property is greater than the critical distance, then it is possible the VEC might not be considered a REC. Also, if the concentration of the COC in the contaminated plume is below the state RSL, it is unlikely the VEC would be considered a REC. If the environmental professional determines the VEC is a REC, then it will be up to the client and the consultant to determine what further investigation, if any, might be appropriate. The rationale supporting the need to consider vapor migration in a Phase I conducted according to E 1527-05 is included in the Legal Appendix. The rationale relied upon definitions included in both CERCLA, AAI, and ASTM E 1527-05. In CERCLA, the definition of release includes the terms emitting and escaping into the environment 7 and the courts have included costs for investigation and remediation of hazardous substance vapors as potentially recoverable response costs. Moreover, in its 2002 draft vapor intrusion guidance document, 8 EPA indicated it was developed for use at CERCLA, RCRA corrective action, and brownfield sites. In the AAI rule, 9 the environmental professional is required to provide an opinion as to whether the inquiry has identified conditions indicative of releases or threatened releases of hazardous substances on, at, in, or to the subject property. The rule further states that the ASTM E 1527-05 standard meets the requirements of an AAI investigation. The ASTM E 1527-05 standard, 4 which is driven by CERCLA, defines a REC 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 into the ground, groundwater or surface water of the property. Stakeholder Concerns Addressed The E 2600-10 standard resolves a number of concerns raised by current and prospective property owners. These include 1. The standard establishes a prescriptive screening methodology for use in conjunction with ASTM E 1527-05 that may be used to evaluate vapor migration. 2. Vapor encroachment screening can avoid potential future investigation expenses that may be required after a property is acquired should state regulators become concerned in the future about potential vapor intrusion issues. 3. Property owners/operators/managers may be able to provide a safer working environment for employees/tenants by screening for vapors that may encroach upon a property being considered for acquisition. 4. Future liability, including potential toxic tort litigation, arising from tenant or other third-party vapor intrusion suits, can potentially be avoided by screening for vapors that may encroach upon a property being considered for acquisition. 5. Property stigma, with consequent property devaluation, due to vapor migration/intrusion 8 em february 2011 awma.org
may be avoided by screening for vapors that may encroach upon a property being considered for acquisition. The standard resolves a number of environmental consultant concerns. These include 1. The standard establishes a screening methodology for use in conjunction with ASTM E 1527-05 that may be used to evaluate vapor migration and assist in making a REC determination. 2. Litigation related to vapor migration/intrusion may be avoided by screening in the Phase I for vapors that may encroach upon a property and potentially cause a vapor intrusion problem. The standard resolves a number of attorney concerns. These include 1. The standard establishes a screening methodology for use in conjunction with an ASTM E 1527-05 Phase I that may be used to evaluate vapor migration. 2. For the Phase I to comply with EPA s AAI regulation and maintain all available defenses to CERCLA liability, the Phase I must consider vapor migration, analogous to groundwater migration, consistent with the REC definition in E 1527-05. The standard resolves a number of lender concerns. These include 1. An adverse impact on the property used as collateral and its value can be avoided by requiring screening for vapor migration when property due diligence is conducted. 2. A potential negative impact [of unexpected vapor intrusion investigation costs] on the borrower s creditworthiness and ability to repay the loan can be avoided by including screening for vapor migration in property due diligence prior to deal closing. 3. Potential foreclosure complications to deal with a vapor migration/intrusion problem can be avoided by screening for vapor migration in property due diligence prior to deal closing. Finally, the standard resolves a number of insurance company concerns. These include 1. Proactive VEC screening by the insurance industry may avoid reopener policy claims at closed (no further action) sites reopened by regulatory agencies in the future to investigate potential vapor intrusion problems. 2. Proactive VEC screening may result in fewer claims related to vapor intrusion against property pollution liability policies. 3. Proactive VEC screening may result in fewer errors and omissions (E&O) claims against policies held by environmental consultants for missing a vapor intrusion problem. 4. Proactive VEC screening may result in avoidance of toxic tort litigation related to vapor intrusion. Implications for Environmental Professionals Environmental professionals conducting a Phase I today must consider vapor migration in their investigation, analogous to groundwater migration. The only choice that exists is the methodology used to evaluate vapor migration. Should their own methodology be used or should the industry consensus methodology identified in E 2600-10 be used? From a liability viewpoint, it is expected that most environmental professionals will rely on ASTM E 2600-10. em References 1. Buonicore, A.J.; Crocker, D.P. Vapor Intrusion and Real Estate Transactions: Uncovering a Hidden Threat; EM December 2005, pp. 32-33. 2. Buonicore, A.J. Development of a New ASTM Standard for Assessment of Vapor Intrusion, EM February 2007, pp. 15-17. 3. ASTM E 2600-10, Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions; ASTM: West Conshohocken, PA, 2010. 4. ASTM Standard Practice E 1527-05 for Environmental Site Assessments: Phase I Environmental Site Assessment Process; ASTM: West Conshohocken, PA, 2005. 5. Buonicore, A.J. Screening for Potential Vapor Intrusion Problems under the Proposed Revisions to the ASTM E 2600 Standard. In Proceedings of the A&WMA Annual Conference & Exhibition, Detroit, MI, 2009, June 16-19; Paper No. 129. 6. Buonicore, A.J. A Smaller Intrusion; Pollution Engineering, May 2009, pp. 26-31. 7. 42 USC 9601 (22). 8. Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway from Groundwater and Soils; EPA530-D-02-004; U.S Environmental Protection Agency, November 2002. 9. 40 CFR 312.11 (C)(I). awma.org february 2011 em 9