4.1 Uses—This guide is intended for use on a voluntary basis by parties who wish to conduct a VES on a parcel of real estate to determine if a VEC is identified for the TP (that is, the presence or likely presence of COC vapors in the vadose zone of the TP caused by the release of vapors from contaminated soil and/or groundwater either on or near the TP as identified by the Tier 1 or Tier 2 procedures in this guide). The process defined in this guide is a screening process that requires information similar to information generally collected as part of an E1527 Phase I ESA as well as additional information described in subsection 5.3 and Section 8 of this guide. If a VEC is identified by this screening process, the user may conduct further investigation. This guide, however, defines a procedure for determining in connection with a property involved in a real estate transaction whether a VEC exists or does not exist. A “VEC exists” determination is appropriate, for example, when there is known COC contamination in, at or on the TP, such as may be the case when COC-contaminated groundwater exists in the subsurface of the TP. A “VEC does not exist” determination is appropriate, for example, when subsurface sampling has confirmed that COC’s are not present. The guide can be applied to property with existing structures, property with structures that will be substantially rehabilitated, property without existing structures but having planned structures (for example, property in development), or property without existing structures and with no planned structures (for example, undeveloped property with no planned development).

4.2 Clarifications on Use: 

4.2.1 Use in Conjunction with E1527 Phase I ESA—This practice, when used in conjunction with E1527 Phase I ESA, may assist the user and environmental professional in developing information about VECs associated with a TP. This guide has utility for a wide range of persons, including those who may not be involved in a real estate transaction.

4.2.2 Independent Use—This guide may be used independent of an E1527 Phase I ESA to determine if a VEC exists or does not exist.

4.2.3 Site-Specific—This guide is property specific in that it relates to screening of VECs associated with a specific parcel of real estate. Consequently, this guide does not address many additional issues raised in transactions such as purchases of business entities or interests therein, or of their assets, that may well involve environmental liabilities pertaining to properties previously owned or operated or other off-site environmental liabilities. The guide does not replace a Phase I ESA conducted by an environmental professional or any obligation of the environmental professional under E1527 to identify all recognized environmental conditions (RECs) related to the TP.

4.3 Who May Conduct—A VES should be performed by an environmental professional. No practical standard can be designed to eliminate the role of professional judgment and the value and need for experience in the party performing the investigation. The professional judgment of an environmental professional is, consequently, vital to the performance of this screening (refer also to Appendix X2). Prior to commencing work, the environmental professional and user should determine the applicability of state professional licensing or registration laws with respect to any vapor intrusion activities to be undertaken to investigate a VEC.

4.4 Additional Services Contracted For—Additional services may be contracted for between the user and the environmental professional. Such additional services may include business environmental risk issues not included within the scope of this guide (see subsection 11.3 for some possible examples).

4.5 Principles—The following principles are an integral part of this guide and are intended to be referred to in resolving any ambiguity or exercising such discretion as is accorded the user or environmental professional in performing a VES.

4.5.1 Uncertainty Not Eliminated in Screening—No vapor encroachment screen, such as included in Sections 8 and 9 of this guide, can wholly eliminate uncertainty regarding the identification of VECs in connection with a TP. Screening is intended to reduce, but not eliminate, uncertainty regarding whether or not a VEC exists in connection with a property.

4.5.2 Not Exhaustive—The guide is not meant to be an exhaustive screening. There is a point at which the cost of information obtained or the time required to gather it outweighs the usefulness of the information and, in fact, may be a material detriment to the orderly completion of real estate transactions. One of the purposes of this guide is to identify a balance between the competing goals of limiting the costs and time demands inherent in performing a VES and the reduction of uncertainty about unknown conditions resulting from additional information.

4.5.3 Level of Investigation is Variable—Not every property will warrant the same level of screening. The appropriate level of screening should be guided by the nature of the property subject to screening and the information already available or developed during the course of the investigation.

4.5.4 Comparison with Subsequent Investigation—It should not be concluded or assumed that an investigation was not adequate because the investigation did not identify VECs in connection with a property. The VES must be evaluated based on the reasonableness of judgments made at the time and under the circumstances in which they were made. Subsequent VESs should not be considered valid bases to judge the appropriateness of any prior screening if based on hindsight, new information, use of developing technology or analytical techniques, or similar factors.

4.6 Continued Viability of VES—Subject to subsection 4.7, a VES conducted according to the procedures presented in this guide and completed less than 180 days before the date of acquisition of the property or, for transactions not involving an acquisition, the date of the intended use of the VES, is presumed to be valid. Subject to subsection 4.7 and the user’s responsibilities set forth in Section 6, a VES conducted according to the procedures presented in this guide and for which the information was collected or updated within one year before the date of acquisition of the property or, for transactions not involving an acquisition, the date of the intended use of the VES may be used provided that the following components of the investigation were conducted or updated within 180 days of the date of purchase or the date of the intended transaction:

4.6.1 Reviews of federal, tribal, state, and local government records;

4.6.2 Update on the operations existing at the TP;

4.6.3 Evaluation of any new potential preferential pathways for vapor migration;

4.6.4 Screening of any new contaminated plume migration that might cause a VEC on the TP; and

4.6.5 Screening of any new contaminant releases in the AOC that might cause a VEC on the TP.

4.7 Use of a Prior VES Screen—This guide recognizes that VESs performed in accordance with this guide will include information that subsequent users may want to use to avoid undertaking duplicative screening procedures. Therefore, this guide describes procedures to be followed to assist users in determining the appropriateness of using information in VESs performed more than one year prior to the date of acquisition of the property or, for transactions not involving an acquisition, the date of the intended use of the VES. The use of a prior VES is based on the following principles that should be adhered to in addition to the specific procedures set forth elsewhere in this guide:

4.7.1 Use of Prior Information—Subject to the criteria set forth in subsection 4.6, users and environmental professionals may use information in a prior VES provided such information was generated as a result of procedures that are consistent with the procedures presented in this guide. However, such information should not be used without current investigation of conditions likely to affect VECs in connection with the TP. Additional investigation may be necessary to document conditions that may have changed materially since the prior VES was conducted.

4.7.2 Contractual Issues Regarding Use of a Prior VES—The contractual and legal obligations between prior and subsequent users of a VES or between environmental professionals who conducted the prior VES and those who would like to use such a prior VES are beyond the scope of this guide.

4.8 Actual Knowledge Exception—If the user or environmental professional conducting a VES has actual knowledge that the information being used from a prior VES is not accurate or if it is obvious, based on other information obtained by means of a Phase I and/or Phase II ESA or known to the person conducting the Phase I and/or Phase II ESA, that the information being used is not accurate, such information from a prior VES may not be used.

4.9 Rules of Engagement—The contractual and legal obligations between an environmental professional and a user (and other parties, if any) are outside the scope of this guide. No specific legal relationship between the environmental professional and the user is necessary for the user to implement the procedures presented in this guide.

1.1 Purpose—The purpose of this guide is to provide practical guidance and a useful process for conducting a vapor encroachment screen (VES) on a property parcel involved in a real estate transaction in the United States of America with respect to chemicals of concern (COC) that may migrate as vapors into the vadose zone of a property as a result of contaminated soil and/or groundwater on or near the property. This guide may be used in conjunction with E1527 but does not alter or in any way define the scope of that practice. In addition, performance of this guide is not a requirement of and does not constitute, expand, or in any way define “all appropriate inquiry” as defined and approved by the U.S. Environmental Protection Agency (EPA) under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and the regulations there under, including 40 CFR Sec. 312.11.

1.1.1 Vapor Encroachment Condition (VEC)—The goal of conducting a VES, as established by this guide, on a parcel of property is to identify a vapor encroachment condition (VEC), which is the presence or likely presence of COC vapors in the vadose zone of the target property (TP) caused by the release of vapors from contaminated soil and/or groundwater either on or near the TP as identified by Tier 1 (see Section 8) or Tier 2 (see Section 9) procedures.

1.1.2 Federal, State, and Local Environmental Laws—This guide does not address requirements of any federal, state, or local laws with respect to vapor intrusion. Users are cautioned that federal, state, and local laws, regulations, or policy may impose vapor encroachment screening or vapor intrusion assessment obligations that are beyond the scope of this guide (information is provided in Appendix X5 and Appendix X9). Users should also be aware that there may be other legal obligations, for example, disclosure, with regard to COC or COC vapors discovered on the TP that are not addressed in this guide. This ASTM practice does not supersede existing federal, state and local statutes and regulations.

1.1.3 Documentation—The scope of this guide includes investigation and reporting actions. Sufficient documentation of all sources, records, and resources used in the investigation procedures that are set out in this guide should be provided in the VES report (refer to Section 10).

1.2 Objectives—Objectives guiding the development of this guide are: (1) to synthesize and put into writing a practical guide for conducting a VES on a property involved in a real estate transaction and (2) to provide that the process to screen for a VEC is practical and reasonable.

1.3 Considerations Outside the Scope—The use of this guide is strictly limited to the scope set forth in this section. Section 11 of this guide identifies, for informational purposes, certain tasks (not an all-inclusive list) that may be conducted on a property that are beyond the scope of this guide but that may warrant consideration by parties to a real estate transaction. Whether to include an investigation of any such conditions in the environmental professional's scope of services should be evaluated by the user and should be agreed upon between the user and environmental professional as additional services beyond the scope of this guide before initiation of a Phase I ESA conducted in conjunction with a VES or initiation of an independent VES.

1.4 Units—The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.

1.5 Organization of this Guide—This guide has eleven sections and nine appendices. The appendices are included for informational purposes and are not part of the procedures prescribed in this guide.

Section 1

contains the scope of the guide.

Section 2

includes the referenced documents.

Section 3

has definitions of terms pertinent to this guide, terms used in this guide but defined in E1527, and acronyms.

Section 4

is directed at the significance and use of this guide.

Section 5

discusses the relationship between this guide and E1527.

Section 6

describes the user's responsibilities under this guide.

Sections 7 – 10

consist of the main body of the VES process, including evaluation and report preparation.

Section 11

provides information regarding non-scope considerations (see 1.3).

Appendix X1

provides legal background for vapor encroachment screening.

Appendix X2

provides guidance on suggested qualifications for the environmental professional conducting the VES.

Appendix X3

provides a sample questionnaire for the environmental professional to obtain pertinent information for the VES from the property owner/operator/occupants.

Appendix X4

provides a recommended table of contents and report format for the VES investigation when not incorporated into a Phase I ESA report.

Appendix X5

includes a listing of federal and state agency web sites that discuss vapor intrusion assessment policies and guidance.

Appendix X6

includes a list of chemicals of potential concern.

Appendix X7

provides general guidance for vapor intrusion assessment and mitigation.

Appendix X8

provides general guidance and references for data collection in the conduct of vapor intrusion investigations.

Appendix X9

provides a supplemental bibliography of federal and state vapor intrusion guidance and other publications that may assist the environmental professional conducting a VES or vapor intrusion assessment.

1.6 This guide does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.

1.7 This guide cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this guide be applied without consideration of a project's many unique aspects. The word “Standard” in the title means only that the guide has been approved through the ASTM consensus process.

1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.