ASTM E2600-22

Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions

SIGNIFICANCE AND USE
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 r...
SCOPE
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 address...

General Information

• Status: Published
• Publication Date: 31-Mar-2022
• ICS: 91.010.10 - Legal aspects
• Technical Committee: E50 - Environmental Assessment, Risk Management and Corrective Action
• Drafting Committee: E50.02 - Real Estate Assessment and Management

Relations

• Refers: ASTM E1903-19 - Standard Practice for Environmental Site Assessments: Phase II Environmental Site Assessment Process
• Effective Date: 15-Nov-2019
• Refers: ASTM E1527-05 - Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process
• Effective Date: 01-Nov-2005
• Refers: ASTM E1527-97 - Standard Practice for Environmental Site Assessments: Phase 1 Environmental Site Assessment Process
• Effective Date: 10-May-2000
• Refers: ASTM E1527-00 - Standard Practice for Environmental Site Assessments: Phase 1 Environmental Site Assessment Process
• Effective Date: 10-May-2000
• Refers: ASTM E1903-97(2002) - Standard Guide for Environmental Site Assessments: Phase II Environmental Site Assessment Process
• Effective Date: 10-Dec-1997
• Refers: ASTM E1903-97 - Standard Guide for Environmental Site Assessments: Phase II Environmental Site Assessment Process
• Effective Date: 10-Dec-1997

Overview

ASTM E2600-22 – Standard Guide for Vapor Encroachment Screening on Property Involved in Real Estate Transactions provides a structured methodology for assessing the potential presence of vapor encroachment conditions (VECs) on parcels of real estate in the United States. Developed by ASTM International, this guide supports environmental due diligence during property transactions by screening for chemicals of concern (COCs) that may migrate as vapors from contaminated soil or groundwater into the vadose zone-the area between the land surface and the groundwater table.

While primarily designed to complement the ASTM E1527 Phase I Environmental Site Assessment (ESA) process, ASTM E2600-22 is also useful as a standalone guide. The standard is significant for property buyers, sellers, developers, lenders, and environmental professionals looking to evaluate the risk and extent of possible vapor intrusion issues on a site. It does not establish legal requirements or substitute for compliance with federal, state, or local environmental laws.

Key Topics

• Vapor Encroachment Screening (VES): A stepwise process using both Tier 1 and Tier 2 evaluations to determine if VECs exist or are likely present on a target property.
• Chemicals of Concern (COCs): Focuses on chemicals with significant volatility and toxicity, such as volatile organic compounds (VOCs), petroleum hydrocarbons, and certain inorganics like mercury, that may impact property value or pose health risks.
• Vadose Zone Considerations: Emphasizes evaluating the unsaturated zone where harmful vapors can migrate due to historical or current contamination.
• Screening Process: Relies on collecting and analyzing available data, such as historical property usage, environmental records, surrounding land uses, and existing contamination reports.
• Professional Judgment: Requires the assessment to be performed by qualified environmental professionals, integrating expertise and professional discretion, especially when interpreting complex site conditions.
• Documentation: Detailed reporting is required, including the rationale for findings, the data sources used, and any recommendations for further investigation.

Applications

ASTM E2600-22 offers practical benefits in several scenarios:

• Real Estate Transactions: Provides buyers, sellers, and lenders with a consistent process to identify and address potential VECs, supporting risk management and informed decision-making.
• Site Development and Redevelopment: Assists developers or property owners in evaluating potential vapor intrusion risks before new construction, substantial rehabilitation, or planning future land use.
• Risk Mitigation: Early identification of vapor encroachment conditions allows for the implementation of mitigation strategies, reducing liability and safeguarding occupant health.
• Supplement to Phase I ESA: When combined with ASTM E1527, this guide helps environmental professionals deliver more comprehensive due diligence reports, particularly when vapor intrusion is a concern.

The standard is applicable to many property types, including developed and undeveloped land, residential, commercial, and industrial sites.

Related Standards

• ASTM E1527: Standard Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process – commonly referenced alongside ASTM E2600-22 during due diligence.
• ASTM E1903: Standard Practice for Environmental Site Assessments: Phase II Environmental Site Assessment Process – used for more detailed site investigations when initial screening raises concerns.
• EPA and State Guidance: Various U.S. EPA and state-level documents provide further guidance on vapor intrusion and environmental assessment.
• OSWER & EPA Technical Guides: Reference materials on evaluating and mitigating vapor intrusion pathways in environmental assessments and property transactions.

By following the ASTM E2600-22 process, stakeholders in real estate can better assess vapor risks, comply with best practices in environmental due diligence, and make more informed decisions regarding property acquisition and redevelopment.

Standards Content (Sample)

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.
Designation: E2600 − 22
Standard Guide for
Vapor Encroachment Screening on Property Involved in
Real Estate Transactions
This standard is issued under the fixed designation E2600; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.1.3 Documentation—The scope of this guide includes
investigation and reporting actions. Sufficient documentation
1.1 Purpose—The purpose of this guide is to provide
of all sources, records, and resources used in the investigation
practical guidance and a useful process for conducting a vapor
procedures that are set out in this guide should be provided in
encroachment screen (VES) on a property parcel involved in a
the VES report (refer to Section 10).
real estate transaction in the United States of America with
respect to chemicals of concern (COC) that may migrate as
1.2 Objectives—Objectives guiding the development of this
vapors into the vadose zone of a property as a result of guide are: (1) to synthesize and put into writing a practical
contaminated soil and/or groundwater on or near the property.
guide for conducting a VES on a property involved in a real
ThisguidemaybeusedinconjunctionwithE1527butdoesnot estate transaction and (2) to provide that the process to screen
alterorinanywaydefinethescopeofthatpractice.Inaddition,
for a VEC is practical and reasonable.
performance of this guide is not a requirement of and does not
1.3 Considerations Outside the Scope—The use of this
constitute, expand, or in any way define “all appropriate
guide is strictly limited to the scope set forth in this section.
inquiry” as defined and approved by the U.S. Environmental
Section 11 of this guide identifies, for informational purposes,
Protection Agency (EPA) under the Comprehensive Environ-
certain tasks (not an all-inclusive list) that may be conducted
mentalResponse,Compensation,andLiabilityAct(CERCLA)
on a property that are beyond the scope of this guide but that
andtheregulationsthereunder,including40CFRSec.312.11.
may warrant consideration by parties to a real estate transac-
1.1.1 Vapor Encroachment Condition (VEC)—The goal of
tion. Whether to include an investigation of any such condi-
conducting a VES, as established by this guide, on a parcel of
tions in the environmental professional’s scope of services
property is to identify a vapor encroachment condition (VEC),
should be evaluated by the user and should be agreed upon
which is the presence or likely presence of COC vapors in the
between the user and environmental professional as additional
vadose zone of the target property (TP) caused by the release
services beyond the scope of this guide before initiation of a
ofvaporsfromcontaminatedsoiland/orgroundwatereitheron
Phase I ESA conducted in conjunction with a VES or initiation
or near the TP as identified by Tier 1 (see Section 8) or Tier 2
of an independent VES.
(see Section 9) procedures.
1.4 Units—The values stated in inch-pound units are to be
1.1.2 Federal, State, and Local Environmental Laws—This
regarded as the standard. The values given in parentheses are
guide does not address requirements of any federal, state, or
mathematical conversions to SI units that are provided for
local laws with respect to vapor intrusion. Users are cautioned
information only and are not considered standard.
that federal, state, and local laws, regulations, or policy may
impose vapor encroachment screening or vapor intrusion
1.5 Organization of this Guide—This guide has eleven
assessment obligations that are beyond the scope of this guide
sections and nine appendices. The appendices are included for
(information is provided in Appendix X5 and Appendix X9).
informational purposes and are not part of the procedures
Users should also be aware that there may be other legal
prescribed in this guide.
obligations, for example, disclosure, with regard to COC or
Section 1 contains the scope of the guide.
COCvaporsdiscoveredonthe TPthatarenotaddressedinthis
Section 2 includes the referenced documents.
Section 3 has definitions of terms pertinent to this guide, terms used
guide.ThisASTMpracticedoesnotsupersedeexistingfederal,
in this guide but defined in E1527, and acronyms.
state and local statutes and regulations.
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.
ThisguideisunderthejurisdictionofASTMCommitteeE50onEnvironmental Sections7– consist of the main body of the VES process, including
10 evaluation and report preparation.
Assessment, Risk Management and CorrectiveAction and is the direct responsibil-
Section 11 provides information regarding non-scope considerations
ity of Subcommittee E50.02 on Real Estate Assessment and Management.
(see 1.3).
Current edition approved April 1, 2022. Published May 2022. Originally
Appendix X1 provides legal background for vapor encroachment screen-
approved in 2008. Last previous edition approved in 2015 as E2600–15. DOI:
ing.
10.1520/E2600–22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2600 − 22
from Subsurface Vapor Sources to Indoor Air, June 2015
Appendix X2 provides guidance on suggested qualifications for the envi-
ronmental professional conducting the VES.
EPA 510-R-15-001,Technical Guide for Addressing Petro-
Appendix X3 provides a sample questionnaire for the environmental pro-
leum Vapor Intrusion at Leaking Underground Storage
fessional to obtain pertinent information for the VES from
the property owner/operator/occupants. Tank Sites, June 2015
Appendix X4 provides a recommended table of contents and report for-
2.4 Other Documents:
mat for the VES investigation when not incorporated into a
Phase I ESA report.
NTP National Toxicology Program,“Annual Report on
Appendix X5 includes a listing of federal and state agency web sites that
Carcinogens,” (latest edition)
discuss vapor intrusion assessment policies and guidance.
IARC InternationalAgency for Research on Cancer“Mono-
Appendix X6 includes a list of chemicals of potential concern.
Appendix X7 provides general guidance for vapor intrusion assessment
graphs” (latest editions)
and mitigation.
Pubchem,“Database of Toxic Effects of Chemical Sub-
Appendix X8 provides general guidance and references for data collec-
stances” (https://pubchem.ncbi,nlm.nih.gov)
tion in the conduct of vapor intrusion investigations.
Appendix X9 provides a supplemental bibliography of federal and state
Vapor Intrusion Regulatory Guidance,https://www.protect-
vapor intrusion guidance and other publications that may
environmental.com/vapor-intrusion-regulatory-guidance-
assist the environmental professional conducting a VES or
by-state/
vapor intrusion assessment.
1.6 This guide does not purport to address all of the safety
3. Terminology
concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety,
3.1 This section provides definitions and descriptions of
health, and environmental practices and determine the appli-
terms used in this guide, terms used in this guide extracted
cability of regulatory limitations prior to use.
from E1527 (some of which have been modified to be
1.7 This guide cannot replace education or experience and
consistentwiththisguide),andalistofacronymsforkeywords
should be used in conjunction with professional judgment. Not
used in this guide. The terms are an integral part of this guide
all aspects of this guide may be applicable in all circum-
and are critical to an understanding of the guide and its use.
stances. This ASTM standard is not intended to represent or
3.2 Definitions of Terms Specific to This Standard:
replace the standard of care by which the adequacy of a given
3.2.1 approximate minimum search distance, n—defined in
professional service must be judged, nor should this guide be
subsection 8.1.3 and also defines the default area of concern
applied without consideration of a project’s many unique
(AOC).
aspects. The word “Standard” in the title means only that the
guide has been approved through the ASTM consensus process.
3.2.2 aquifer, n—rockorsedimentinaformation,agroupof
1.8 This international standard was developed in accor-
formations, or part of a formation that is saturated and
dance with internationally recognized principles on standard-
sufficiently permeable to transmit water to wells or springs.
ization established in the Decision on Principles for the
3.2.3 area of concern (AOC), n—defined in subsections
Development of International Standards, Guides and Recom-
8.1.2, 8.1.3 and 8.1.4 and is defined by the approximate
mendations issued by the World Trade Organization Technical
minimum search distance adjusted as appropriate. When the
Barriers to Trade (TBT) Committee.
AOC is defined by the approximate minimum search distance
without adjustment, the AOC is the default AOC.
2. Referenced Documents
3.2.4 biodegradation, n—process by which microbial or-
2.1 ASTM Standards:
ganisms transform or alter (through metabolic, enzymatic, or
E1527PracticeforEnvironmentalSiteAssessments:PhaseI
other action) the structure of chemicals present in the environ-
Environmental Site Assessment Process
ment.
E1903Practice for Environmental Site Assessments: Phase
II Environmental Site Assessment Process
3.2.5 chemical(s) of concern, COC, n—chemical that is
present in the subsurface environment, has a vapor pressure
2.2 Federal Statutes:
42 U.S.C. U.S. Code, Title 42,The Public Health and greater than 1 mm of mercury, or a Henry’s Law Constant
-5 3
greater than 1×10 atm m /mole at ambient temperature and
Welfare, Solid Waste Disposal, Identification and Listing
of Hazardous Wastes, §6901, 6903, 6921; 42 U.S.C. U.S. pressure,andcanpotentiallymigrateasavaporintothevadose
Code, Title 42, Comprehensive Environmental Response, zone of the TP.
Compensation and Liability Act, 9605, 9601, et seq.
3.2.5.1 Discussion—COC generally meet specific criteria
for volatility (see 3.2.39) and toxicity (see 3.2.34) and include
2.3 USEPA Documents:
40 CFR Title 40,Protection of Environment, Chapter 1, volatile organic compounds, semi-volatile organic compounds,
Environmental Protection Agency, Parts 300, 302, 312, petroleum hydrocarbons, and volatile inorganic analytes (such
355, et seq. as mercury). A list of COC is presented in Appendix X6.A
OSWER Publication 9200.2-154,OSWER Technical Guide chemical’s molecular weight has also been suggested as a
forAssessing and Mitigating theVapor Intrusion Pathway criterion for volatility (with a threshold of 200 g/mole).
However, EPA indicated in its June 2015 Vapor Intrusion
Guidance that it is not considering a chemical’s molecular
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
weight because molecular weight is only a weak predictor of
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
volatility. Those chemicals with a molecular weight greater
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. than200g/moleareidentifiedwithanasteriskinAppendixX6.
E2600 − 22
3.2.6 conduit, n—preferential pathway along which vapors compound in water under equilibrium conditions; Henry’s law
released from contaminated soil and/or groundwater may constants are temperature dependent.
migrate onto the TP or away from the TP.
3.2.17 hydrocarbon, n—chemical compound composed
3.2.7 contaminant, n—anyphysical,chemical,biological,or only of carbon and hydrogen atoms.
radiological substance or matter that has an adverse effect on
3.2.18 moisture content (of soil), n—amount of water lost
air, water, or soil.
from soil upon drying to a constant weight expressed as the
3.2.8 contaminated plume, n—plume in which concentra- weightperunitweightofdrysoilorasthevolumeofwaterper
tions of COC are known to be present in the soil or ground- unit bulk volume of the soil.
water or both at concentrations exceeding levels that generally 3.2.18.1 Discussion—For a fully saturated medium, mois-
wouldbethesubjectofanenforcementactionifbroughttothe
turecontentexpressedasavolumefractionequalstheporosity.
attention of appropriate governmental agencies.
3.2.19 nonaqueous phase liquid, NAPL, n—substances that
3.2.8.1 Discussion—A contaminated plume can take the
do not dissolve readily in water and that remain in the original
form of a groundwater contaminated plume or a soil contami-
bulk liquid form in the subsurface.
nated plume.Inagroundwater contaminated plume, COCmay
3.2.19.1 Discussion—Light NAPL (LNAPL), such as
beconveyedas solutesawayfromthepointatwhichtheywere
gasoline,islessdensethanwaterandcanaccumulateabovethe
introduced into groundwater. They move with the migrating
water table, while dense NAPL (DNAPL), such as many
groundwater mass in the direction of groundwater flow. When
chlorinated solvents, including trichloroethylene and
dispersion within the groundwater contaminated plume brings
perchloroethylene, are more dense than water and can pen-
a dissolved COC to the groundwater-soil gas interface, the
etrate into the water table.
COC may transition from the dissolved state to the vapor state
3.2.20 permeability, n—qualitative description of the rela-
andmigratefromgroundwaterintosoilgasinthevadosezone.
tiveeasewithwhichrock,soil,orsedimentwilltransmitafluid
Once a COC migrates into soil gas in the vadose zone, its
(that is, a liquid or gas).
migration may no longer be dependent on or related to
groundwater movement. In a soil contaminated plume, COC 3.2.21 petroleum, n—crudeoiloranyfractionthereofthatis
volatilized from the soil mix freely with soil gas that exists liquidatstandardconditionsoftemperatureandpressure(60°F
at 14.7 psia).
within soil voids in the vadose zone. COC in the soil gas can
alsobeintroducedfromunderlyingcontaminatedgroundwater, 3.2.21.1 Discussion—The term includes substances com-
as a result of a liquid spill into vadose zone soils, or by the prised of a complex blend of hydrocarbons derived from crude
direct release of vapors from a leaking underground source. oil through the process of separation, conversion, upgrading,
Migration of COC contaminated soil gas through the vadose and finishing, such as motor fuels, jet oils, lubricants, and
zonemaybeinanydirection;however,itpreferentiallyfollows petroleum solvents, and also includes used oils.
thepathofleastresistance.Fluctuationsinbarometricpressure
3.2.22 petroleum hydrocarbon chemicals of concern, n—for
may cause movement of air and vapors into and out of the
thepurposeofthisguide,thosevolatilepetroleumhydrocarbon
vadose zone through preferential pathways.
compounds are a subset of COC and readily biodegrade to
3.2.9 contaminated property, n—property on which soil or
carbon dioxide and water by soil microbes in aerated environ-
groundwater or both contains chemicals of concern (COC) or ments.
otherwise hazardous substances at concentrations exceeding
3.2.22.1 Discussion—Petroleum hydrocarbon chemicals of
levels that generally would be the subject of an enforcement concern may be present in several forms in environmental
action if brought to the attention of appropriate governmental
media, including adsorbed to soil, as constituents of LNAPL
agencies. above the water table, as dissolved solutes in groundwater, or
as vapors in soil gas.
3.2.10 critical distance, n—defined in subsection 9.2.
3.2.23 Phase I environmental site assessment, ESA,
3.2.11 dwelling, n—structure or portion thereof used for
n—process described in E1527.
residential habitation.
3.2.24 porosity, n—volume fraction of a rock or unconsoli-
3.2.12 environmental professional, n—person meeting the
dated sediment not occupied by solid material but usually
education,training,andexperiencerequirementsassetforthin
occupied by liquids, gas, and/or air.
40CFR312.10(b),whichistherequirementsetforthinE1527
(see subsection 3.3.5).
3.2.25 preferential pathway, n—pathway that has the least
amount of constraint on the migration of COC vapors.
3.2.13 findings, n—defined in subsection 10.2.2.
3.2.25.1 Discussion—Preferential pathways are natural or
3.2.14 fracture, n—break in a rock formation.
man-made and may provide direct contact between the subsur-
3.2.14.1 Discussion—Faults, shears, joints, and planes of
face of a property and the vapor contaminant source (that is,
fracture cleavage are types of fractures. The presence of
the location on a property where the contaminated vapor
fracturesmayacceleratemigrationof COCsalongthefracture.
intersects the preferential pathway). Natural preferential path-
3.2.15 groundwater, n—water contained in the pore spaces
ways may include, for example, vertically fractured bedrock
of saturated geologic media.
where the fractures are interconnected and in direct contact
3.2.16 Henry’s law, n—relationship between the partial with the subsurface of a property and the vapor contaminant
pressure of a compound in air and the concentration of that source. Man-made preferential pathways may include, for
E2600 − 22
example, utility conduits and sewers. The presence of prefer- could be no vadose zone, such as the case of a building
ential pathways may also direct migrating COC vapors away foundationsittingbelowthewatertable.Inthiscase,itmaybe
from a TP. possible for COC vapors to adversely impact the indoor air
without migrating through a vadose zone.
3.2.26 real estate, n—undeveloped real property, real prop-
erty used for industrial, retail, office, agricultural, other
3.2.38 volatile organic compound, VOC, n—general term
commercial, medical, or educational purposes, or property
foranorganiccompoundthathassufficientvaporpressure(for
used as a single family or multi-family residential dwelling.
example, greater than 1 mm Hg) at standard temperature
(20°C) and pressure (1 atm) to significantly vaporize and enter
3.2.27 real estate transaction, n—transfer of title to or
the atmosphere.
possession of real property or receipt of a security interest in
real property.
3.2.39 volatility, n—chemicalisconsideredtobesufficiently
-5
3.2.28 report, n—document prepared by an environmental volatile if its Henry’s law constant is greater than 10
3 -1
professional pursuant to Section 10.
atm-m -mol and its vapor pressure is greater than 1 mm Hg
at room temperature.
3.2.29 saturated zone, n—zone in which all of the voids in
therockorsoilarefilledwithwateratapressurethatisgreater 3.2.39.1 Discussion—A chemical’s molecular weight has
also been used as an indicator of volatility, with the threshold
than atmospheric.
molecular weight being approximately 200 g/mole. EPAin its
3.2.29.1 Discussion—The water table is the top of the
June 2015 Vapor Intrusion Guidance does not use the molecu-
saturated zone in an unconfined aquifer.
larweightcriterionbecausethiscriterionisbelievedtobeonly
3.2.30 semi-volatile organic compound, n—generaltermfor
a weak predictor of volatility.
an organic compound that has sufficient vapor pressure at
standard temperature (20°C) and pressure (1 atm) to vaporize
3.2.40 water table, n—top of the saturated zone in an
(albeit at a slower rate than volatile organic compounds) and unconfined aquifer.
enter the atmosphere.
3.3 Terms Used in This Guide—Some terms have been
3.2.31 solute, n—substance such as a contaminant that is
modified to be consistent with this guide.
dissolved in another substance such as groundwater.
3.3.1 adjoining properties, n—any real property or proper-
ties the border of which is contiguous or partially contiguous
3.2.32 target property, TP, n—property involved in the real
with that of the target property, or that would be contiguous or
estate transaction that is the subject of the VES defined by this
partially contiguous with that of the target property but for a
guide.
street, road, or other public thoroughfare separating them.
3.2.33 toxic chemical, n—chemical whose vapor concentra-
tionofthepurecomponentposeseitheranincrementallifetime
3.3.2 business environmental risk, n—risk that can have a
cancerrisk(ILCR)oranon-cancerhazardquotientgreaterthan material environmental or environmentally driven impact on
acceptable values established by applicable federal, state, or
the transaction or the business associated with the current or
local regulatory agencies.
planned use of a parcel of real estate, not limited to environ-
mental issues that are investigated pursuant to this guide.
3.2.34 toxicity, n—effect on human health that is exhibited
Consideration of business environmental risk issues may in-
by a toxic chemical; for the purposes of this guide, toxicity is
volve addressing one or more non-scope considerations, some
definedasachemicalexhibitinganincrementallifetimecancer
-6
of which are identified in Section 11 of this guide.
riskgreaterthan10 oranon-cancerHazardIndexgreaterthan
1.
3.3.3 Comprehensive Environmental Response,
Compensation, and Liability Information System (CERCLIS),
3.2.35 user, n—party who commissions the performance of
n—list of sites compiled by EPA that EPA has investigated or
a VES pursuant to this guide.
is currently investigating for potential hazardous substance
3.2.35.1 Discussion—Commonly, the user is the prospec-
contamination and for possible inclusion on the National
tive purchaser of a parcel of property.
Priorities List (the CERCLIS information system supporting
3.2.36 vadose zone (or unsaturated zone), n—zone between
CERCLAhas been retired by EPAand replaced by SEMS, the
the land surface and the water table within which moisture
Superfund Enterprise Management System).
content is less than saturation (except in the capillary fringe)
3.3.4 CORRACTS list, n—listof hazardous wastetreatment,
and pressure is less than atmospheric.
storage, or disposal facilities and other RCRA-regulated facili-
3.2.36.1 Discussion—Soil pore space typically contains air
ties (because of past interim status or storage of hazardous
or other gases. The capillary fringe is included in the vadose
waste beyond 90 days) that have been notified by the EPA to
zone.
undertake corrective action under RCRA.The CORRACTS list
3.2.37 vapor encroachment condition, VEC, n—presence or
can be derived from the EPA database that manages RCRA
likely presence of COC vapors in the vadose zone of the TP
data.
caused by the release of vapors from contaminated soil and/or
groundwater either on or near the TP as identified by the Tier
3.3.5 environmental professional, n—person meeting the
1 (see Section 8) or Tier 2 (see Section 9) procedures in this
education,training,andexperiencerequirementsassetforthin
guide.
40 CFR 312.10(b). The person may be an independent con-
3.2.37.1 Discussion—Conditions may exist where there tractor or an employee of the user.
E2600 − 22
3.3.6 environmental site assessment, ESA, n—process by 3.3.17 owner, n—generally the fee owner of record of the
which a person or entity seeks to determine if a particular property.
parcel of real property (including improvements) is subject to
3.3.18 petroleum products, n—those substances included
recognized environmental conditions (see subsection 3.3.22).
withinthemeaningofthepetroleumexclusiontoCERCLA,42
3.3.7 fire insurance maps, n—mapsproducedforprivatefire U.S.C.§9601(14),asinterpretedbythecourtsandEPA,thatis:
insurance map companies that indicate uses of properties at petroleum, including crude oil or any fraction thereof which is
specified dates and that encompass the property. These maps not otherwise specifically listed or designated as a hazardous
areoftenavailableatlocallibraries,historicalsocieties,private substance under Subparagraphs (A) through (F) of 42 U.S.C.
resellers, or from the map companies who produced them. §9601(14), natural gas, natural gas liquids, liquefied natural
gas, and synthetic gas usable for fuel (or mixtures of natural
3.3.8 hazardous substance, n—substance defined as a haz-
gasandsuchsyntheticgas).(Thewordfractionreferstocertain
ardous substancepursuanttoCERCLA42U.S.C.9601(14),as
distillates of crude oil, including but not limited to gasoline,
interpreted by EPA regulations and the courts.
kerosene,dieseloil,jetfuels,andfueloil,pursuanttoStandard
3.3.9 hazardous waste, n—any hazardous waste having the 3
Definitions of Petroleum Statistics. )
characteristics identified under or listed pursuant to Section
3.3.19 publicly available, adj—information that is publicly
3001 of RCRA, as amended (42 U.S.C. 6921) (but not
available means that the source of the information allows
including any waste the regulation of which under RCRA (42
access to the information by anyone upon request.
U.S.C. 6901-6992k) has been excluded by Act of Congress).
3.3.20 practically reviewable, adj—informationthatis prac-
RCRA defines a hazardous waste, at 42 U.S.C. 6903, as: “a
solid waste, or combination of solid wastes, which because of tically reviewable means that the information is provided by
the source in a manner and in a form that, upon examination,
its quantity, concentration or physical, chemical or infectious
characteristics may (A) cause, or significantly contribute to an yieldsinformationrelevanttothepropertywithouttheneedfor
extraordinary analysis of irrelevant data. The form of the
increase in mortality or an increase in serious irreversible or
incapacitating reversible illness; or (B) pose a substantial informationshouldbesuchthatthe usercanreviewtherecords
for a limited geographic area. Records that cannot be feasibly
presentorpotentialhazardtohumanhealthortheenvironment
when improperly treated, stored, transported or disposed of, or retrieved by reference to the location of the property or a
geographic area in which the property is located are not
otherwise managed.”
generally practically reviewable. Most databases of public
3.3.10 landfill, n—place, location, tract of land, area, or
recordsare practically reviewableiftheycanbeobtainedfrom
premises used for the disposal of solid wastes as defined by
the source agency by the county, city, zip code, or other
state solid waste regulations.The term is synonymous with the
geographic area of the facilities listed in the record system.
term solid waste disposal site and is also known as a garbage
Records that are sorted, filed, organized, or maintained by the
dump, trash dump, or similar term.
source agency only chronologically are not generally practi-
3.3.11 local government agencies, n—those agencies of
cally reviewable. Listings in publicly available records that do
municipal or county government having jurisdiction over the
nothaveadequateaddressinformationtobelocatedgeographi-
target property. Municipal and county government agencies
cally are not generally considered practically reviewable.
include but are not limited to cities, parishes, townships, and
3.3.21 reasonably ascertainable, adj—information that is
similar entities.
(1) publicly available, (2) obtainable from its source within
3.3.12 local street directories, n—directories published by
reasonable time and cost constraints, and (3) practically
private (or sometimes government) sources that show
reviewable.
ownership,occupancy,and/oruseofsitesbyreferencetostreet
3.3.22 recognized environmental condition, n—(1) the pres-
addresses. Often local street directories are available at
ence of hazardous substances or petroleum products in, on, or
libraries, or historical societies, and/or local municipal offices.
at the subject property due to a release to the environment; (2)
3.3.13 National Priorities List, NPL, n—list compiled by
the likely presence of hazardous substances or petroleum
EPA pursuant to CERCLA 42 U.S.C. §9605(a)(8)(B) of prop-
products in, on, or at the subject property due to a release or
erties with the highest priority for cleanup pursuant to EPA’s
likely release to the environment;or (3) the presence of
Hazard Ranking System. See 40 C.F.R. Part 300.
hazardous substances or petroleum products in, on, or at the
3.3.13.1 Discussion—The CERCLIS information system
subject propertyunderconditionsthatposea material threatof
supporting CERCLAhas been retired by EPAand replaced by
a future release to the environment.
SEMS, the Superfund Enterprise Management System.
3.3.22.1 Discussion—For the purposes of this definition,
3.3.14 obvious, adv—that which is plain or evident; a
“likely” is that which is neither certain nor proved, but can be
condition or fact that could not be ignored or overlooked by a expected or believed by a reasonable observer based on the
reasonable observer while visually or physically observing the
logic and/or experience of the environmental professional,
property. and/or available evidence, as stated in the report to support the
opinions given therein.
3.3.15 occupants, n—those tenants, subtenants, or other
personsorentitiesusingapropertyoraportionoftheproperty.
3.3.16 operator, n—person responsible for the overall op-
Standard Definitions of Petroleum Statistics, American Petroleum Institute,
eration of a facility. Fourth Edition, 1988.
E2600 − 22
3.3.22.2 Discussion—de minimis conditions—The REC 4. Significance and Use
term is not intended to include de minimis conditions that
4.1 Uses—This guide is intended for use on a voluntary
generallydonotpresentamaterialriskofharmtopublichealth
basis by parties who wish to conduct a VES on a parcel of real
or the environment and that generally would not be the subject
estatetodetermineifa VECisidentifiedforthe TP(thatis,the
of an enforcement action if brought to the attention of
presence or likely presence of COC vapors in the vadose zone
appropriate governmental agencies. Conditions determined to
of the TP caused by the release of vapors from contaminated
be de minimis are not RECs.
soil and/or groundwater either on or near the TP as identified
3.3.23 records review, n—that part that is contained in
by the Tier 1 or Tier 2 procedures in this guide). The process
Section 8 of this guide that addresses which records should or
defined in this guide is a screening process that requires
may be reviewed.
information similar to information generally collected as part
3.3.24 solid waste disposal site, n—place, location, tract of of an E1527 Phase I ESA as well as additional information
land, area, or premises used for the disposal of solid wastes as described in subsection 5.3 and Section 8 of this guide. If a
defined by state solid waste regulations. The term is synony- VEC is identified by this screening process, the user may
mous with the term landfill and is also known as a garbage
conduct further investigation. This guide, however, defines a
dump, trash dump, or similar term.
procedure for determining in connection with a property
involved in a real estate transaction whether a VEC exists or
3.3.25 solvent, n—chemical compound that is capable of
doesnotexist.A“VECexists”determinationisappropriate,for
dissolving another substance and may itself be a hazardous
example, when there is known COC contamination in, at or on
substance, used in a number of manufacturing/industrial pro-
the TP, such as may be the case when COC-contaminated
cesses including but not limited to the manufacture of paints
groundwater exists in the subsurface of the TP.A“VEC does
and coatings for industrial and household purposes, equipment
not exist” determination is appropriate, for example, when
clean-up, and surface degreasing in metal fabricating indus-
subsurface sampling has confirmed that COC’s are not present.
tries.
The guide can be applied to property with existing structures,
3.3.26 standard environmental record sources, n—those
property with structures that will be substantially rehabilitated,
records specified in subsection 8.1.3 of this guide.
property without existing structures but having planned struc-
3.3.27 standard historical sources, n—those sources of
tures (for example, property in development), or property
information about the history of uses of a property as specified
without existing structures and with no planned structures (for
in subsection 8.4 of this guide.
example,undevelopedpropertywithnoplanneddevelopment).
3.4 Acronyms:
4.2 Clarifications on Use:
3.4.1 AOC—Area of concern
4.2.1 Use in Conjunction with E1527 Phase I ESA—This
3.4.2 CERCLA—Comprehensive Environmental Response,
practice, when used in conjunction with E1527 Phase I ESA,
Compensation and Liability Act of 1980 (as amended, 42
may assist the user and environmental professional in devel-
U.S.C. §§9601 et seq.)
oping information about VECs associated with a TP. This
guide has utility for a wide range of persons, including those
3.4.3 CFR—Code of Federal Regulations
who may not be involved in a real estate transaction.
3.4.4 COC—Chemical(s) of concern
4.2.2 Independent Use—This guide may be used indepen-
3.4.5 DNAPL—Dense nonaqueous phase liquid (a separate
dent of an E1527 Phase I ESA to determine if a VEC exists or
phase groundwater contaminant that is both denser than water
does not exist.
and its concentration exceeds its solubility in water)
4.2.3 Site-Specific—This guide is property specific in that it
3.4.6 EPA—UnitedStatesEnvironmentalProtectionAgency
relatestoscreeningof VECsassociatedwithaspecificparcelof
real estate. Consequently, this guide does not address many
3.4.7 ESA—Environmental site assessment
additional issues raised in transactions such as purchases of
3.4.8 LNAPL—Light nonaqueous phase liquid (a separate
businessentitiesorintereststherein,oroftheirassets,thatmay
phase groundwater contaminant that is less dense than water
well involve environmental liabilities pertaining to properties
and its concentration exceeds its solubility in water)
previously owned or operated or other off-site environmental
3.4.9 NAPL—Nonaqueous phase liquid
liabilities.Theguidedoesnotreplacea Phase I ESAconducted
by an environmental professional or any obligation of the
3.4.10 NPL—National Priorities List
environmental professional under E1527 to identify all recog-
3.4.11 REC—Recognized environmental condition
nized environmental conditions (RECs) related to the TP.
3.4.12 TP—Target property
4.3 Who May Conduct—A VES should be performed by an
3.4.13 USC—United States Code
environmental professional. No practical standard can be
3.4.14 USGS—United States Geological Survey
designedtoeliminatetheroleofprofessionaljudgmentandthe
value and need for experience in the party performing the
3.4.15 VEC—Vapor encroachment condition
investigation. The professional judgment of an environmental
3.4.16 VES—Vapor encroachment screen
professional is, consequently, vital to the performance of this
3.4.17 VOC—Volatile organic compound screening (refer also to Appendix X2). Prior to commencing
E2600 − 22
work, the environmental professional and user should deter- following components of the investigation were conducted or
mine the applicability of state professional licensing or regis- updated within 180 days of the date of purchase or the date of
tration laws with respect to any vapor intrusion activities to be the intended transaction:
undertaken to investigate a VEC. 4.6.1 Reviews of federal, tribal, state, and local government
records;
4.4 Additional Services Contracted For—Additional ser-
4.6.2 Update on the operations existing at the TP;
vices may be contracted for between the user and the environ-
4.6.3 Evaluation of any new potential preferential pathways
mental professional. Such additional services may include
for vapor migration;
business environmental risk issues not included within the
4.6.4 Screening of any new contaminated plume migration
scope of this guide (see subsection 11.3 for some possible
that might cause a VEC on the TP; and
examples).
4.6.5 Screening of any new contaminant releases in the
4.5 Principles—Thefollowingprinciplesareanintegralpart
AOC that might cause a VEC on the TP.
ofthisguideandareintendedtobereferredtoinresolvingany
4.7 Use of a Prior VES Screen—This guide recognizes that
ambiguity or exercising such discretion as is accorded the user
VESs performed in accordance with this guide will include
or environmental professional in performing a VES.
information that subsequent users may want to use to avoid
4.5.1 Uncertainty Not Eliminated in Screening—No vapor
undertaking duplicative screening procedures. Therefore, this
encroachment screen, such as included in Sections 8 and 9 of
guide describes procedures to be followed to assist users in
this guide, can wholly eliminate uncertainty regarding the
determining the appropriateness of using information in VESs
identification of VECs in connection with a TP. Screening is
performed more than one year prior to the date of acquisition
intended to reduce, but not eliminate, uncertainty regarding
ofthepropertyor,fortransactionsnotinvolvinganacquisition,
whether or not a VEC exists in connection with a property.
the date of the intended use of the VES.The use of a prior VES
4.5.2 Not Exhaustive—The guide is not meant to be an
is based on the following principles that should be adhered to
exhaustive screening. There is a point at which the cost of
inadditiontothespecificproceduressetforthelsewhereinthis
information obtained or the time required to gather it out-
guide:
weighs the usefulness of the information and, in fact, may be
4.7.1 Use of Prior Information—Subject to the criteria set
a material detriment to the orderly completion of real estate
forth in subsection 4.6, users and environmental professionals
transactions. One of the purposes of this guide is to identify a
may use information in a prior VES provided such information
balance between the competing goals of limiting the costs and
wasgeneratedasaresultofproceduresthatareconsistentwith
time demands inherent in performing a VES and the reduction
the procedures presented in this guide. However, such infor-
of uncertainty about unknown conditions resulting from addi-
mation should not be used without current investigation of
tional information.
conditions likely to affect VECs in connection with the TP.
4.5.3 Level of Investigation is Variable—Noteveryproperty
Additional investigation may be necessary to document con-
will warrant the same level of screening.The appropriate level
ditions that may have changed materially since the prior VES
of screening should be guided by the nature of the property
was conducted.
subject to screening and the information already available or
4.7.2 Contractual Issues Regarding Use of a Prior VES—
developed during the course of the investigation.
The contractual and legal obligations between prior and
4.5.4 Comparison with Subsequent Investigation—It should
subsequent users of a VES or between environmental profes-
not be concluded or assumed that an investigation was not
sionalswhoconductedtheprior VESandthosewhowouldlike
adequate because the investigation did not identify VECs in
to use such a prior VES are beyond the scope of this guide.
connection with a property. The VES must be evaluated based
4.8 Actual Knowledge Exception—If the user or environ-
onthereasonablenessofjudgmentsmadeatthetimeandunder
mental professional conducting a VES has actual knowledge
the circumstances in which they were made. Subsequent VESs
that the information being used from a prior VES is not
should not be considered valid bases to judge the appropriate-
accurateorifitis obvious,basedonotherinformationobtained
ness of any prior screening if based on hindsight, new
by means of a Phase I and/or Phase II ESA or known to the
information, use of developing technology or analytical
person conducting the Phase I and/or Phase II ESA, that the
techniques, or similar factors.
information being used is not accurate, such information from
4.6 Continued Viability of VES—Subjecttosubsection4.7,a
a prior VES may not be used.
VES conducted according to the procedures presented in this
4.9 Rules of Engagement—The contractual and legal obli-
guide and completed less than 180 days before the date of
gationsbetweenan environmental professionalanda user(and
acquisition of the property or, for transactions not involving an
other parties, if any) are outside the scope of this guide. No
acquisition, the date of the intended use of the VES,is
specific legal relationship between the environmental profes-
presumed to be valid. Subject to subsection 4.7 and the user’s
sional and the user is necessary for the user to implement the
responsibilities set forth in Section 6,a VES conducted
procedures presented in this guide.
according to the procedures presented in this guide and for
which the information was collected or updated within one
5. Relationship to E1527 Phase I ESA
year before the date of acquisition of the property or, for
transactions not involving an acquisition, the date of the 5.1 Identification of a REC Pursuant to a Phase I ESA—
intended use of the VES may be used provided that the RECs are identified only through the performance of an E1527
E2600 − 22
Phase I ESA.Thus, a finding pursuant to this guide that a VEC TP.The userorthe environmental professionalorbothneedto
exists at the TP is not a determination that a REC exists at the determine the best methods for obtaining information that may
TP. Whether a REC exists at a TP as a result of the impact of beusefulintheconductofthe VES,recognizingthat,absentan
possible vapor migration into the vadose zone of the TP is a applicable legal requirement, the property user, operator,
separate determination to be made by the environmental and/or occupants are not required to provide such information
professional pursuant to E1527. This guide does not constitute to the user or the environmental professional. Subsection
or meet the requirements for conducting “all appropriate Appendix X3 provides a sample questionnaire that identifies
inquiry” or any part of “all appropriate inquiry” as defined by information on the TP that may be useful in conducting a VES
U.S. EPA under CERCLA and the regulations there under, and identifying VECs in connection with the TP.
including 40 CFR Sec. 312.11.
6.2 Specialized Knowledge or Experience of the User—The
5.2 VES—The VES established by this guide is intended to environmental professional conducting the VES should ask the
be used independently of or in conjunction with E1527 Phase
user if the user has any specialized knowledge or experience
I ESA. that may be important to the screening of VECs in connection
5.2.1 The VES may be conducted concurrently with the with the TP.Itisthe user’s responsibility to respond to the
questions asked by the environmental professional with infor-
E1527 Phase I ESA.
mation based on such specialized knowledge or experience.
5.2.2 The VES may be conducted independent of an E1527
The user should respond to the environmental professional’s
Phase I ESA. When conducting a VES pursuant to this guide,
questions before the environmental professional conducts the
the data collection actions specified in this guide should be
VES. Such specialized knowledge might include, for example,
implemented (see subsection 5.3 and Section 8).
tenant odor complaints or occupancy-related health issues.
5.3 Use of Information Collected in a Phase I ESA Con-
6.3 Commonly Known or Reasonably Ascertainable
ducted in Accordance with the E1527 Standard—Thescreening
(see Section 8) identified in this guide makes use of informa- Information—The environmental professional conducting the
VESshouldaskthe userifthe userisawareofanyinformation
tion similar to information generally collected as part of an
E1527 Phase I ESAaswellasadditionalinformationdescribed commonlyknownor reasonably ascertainablewithinthelocal
community about the TP that the environmental professional
below and in Section 8 of this guide. The information that
shouldbecollectedincludes,butisnotlimitedto,federal,state, informs the user may be important to the screening of VECs in
connection with the TP.Itisthe user’s responsibility to
local, and tribal government records, chemical use and histori-
cal records of prior uses on the TP and within the AOC respond to questions asked by the environmental professional.
The user should respond to the environmental professional’s
surrounding the TP as determined by the p
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E2600 − 15 E2600 − 22
Standard Guide for
Vapor Encroachment Screening on Property Involved in
Real Estate Transactions
This standard is issued under the fixed designation E2600; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
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 Practice 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
This guide is under the jurisdiction of ASTM Committee E50 on Environmental Assessment, Risk Management and Corrective Action and is the direct responsibility
of Subcommittee E50.02 on Real Estate Assessment and Management.
Current edition approved Oct. 1, 2015April 1, 2022. Published December 2015May 2022. Originally approved in 2008. Last previous edition approved in 20102015 as
E2600 – 10.E2600 – 15. DOI: 10.1520/E2600–15.10.1520/E2600–22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2600 − 22
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 Practice E1527, and acronyms.
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 Practice
E1527.
Section 5 discusses the relationship between this guide and E1527.
Section 6 describes the user’s responsibilities under this guide.
Sections 7 – consist of the main body of the VES process, including
10 evaluation and report preparation.
Section 11 provides information regarding non-scope considerations
(see 1.3).
Appendix X1 provides legal background for vapor encroachment screen-
ing.
Appendix X2 provides guidance on suggested qualifications for the envi-
ronmental professional conducting the VES.
Appendix X3 provides a sample questionnaire for the environmental pro-
fessional to obtain pertinent information for the VES from
the property owner/operator/occupants.
Appendix X4 provides a recommended table of contents and report for-
mat 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 collec-
tion 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 guidestandard to establish appropriate safety safety, health, and healthenvironmental 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 guidestandard 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.
2. Referenced Documents
2.1 ASTM Standards:
E1527 Practice for Environmental Site Assessments: Phase I Environmental Site Assessment Process
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
E2600 − 22
E1903 Practice for Environmental Site Assessments: Phase II Environmental Site Assessment Process
2.2 Federal Statutes:
42 U.S.C. U.S. Code, Title 42, The Public Health and Welfare, Solid Waste Disposal, Identification and Listing of Hazardous
Wastes, §6901, 6903, 6921; 42 U.S.C. U.S. Code, Title 42, Comprehensive Environmental Response, Compensation and
Liability Act, 9605, 9601, et seq.
2.3 USEPA Documents:
40 CFR Title 40, Protection of Environment, Chapter 1, Environmental Protection Agency, Parts 300, 302, 312, 355, et seq.
OSWER Publication 9200.2-154, OSWER Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from
Subsurface Vapor Sources to Indoor Air, June 2015
EPA 510-R-15-001, Technical Guide for Addressing Petroleum Vapor Intrusion at Leaking Underground Storage Tank Sites,
June 2015
2.4 Other Documents:
NTP National Toxicology Program, “Annual Report on Carcinogens,” (latest edition)
IARC International Agency for Research on Cancer “Monographs” (latest editions)
NIOSH National Institute for Occupational Safety and Health,Pubchem, “Registry“Database of Toxic Effects of Chemical
Substances” (https://pubchem.ncbi,nlm.nih.gov)
Vapor Intrusion Regulatory Guidance, https://www.protectenvironmental.com/vapor-intrusion-regulatory-guidance-by-state/
3. Terminology
3.1 This section provides definitions and descriptions of terms used in this guide, terms used in this guide extracted from Practice
E1527 (some of which have been modified to be consistent with this guide), and a list of acronyms for keywords used in this guide.
The terms are an integral part of this guide and are critical to an understanding of the guide and its use.
3.2 Definitions of Terms Specific to This Standard:
3.2.1 approximate minimum search distance, n—defined in subsection 8.1.3 and also defines the default area of concern (AOC).
3.2.2 aquifer, n—rock or sediment in a formation, a group of formations, or part of a formation that is saturated and sufficiently
permeable to transmit water to wells or springs.
3.2.3 area of concern (AOC), n—defined in subsections 8.1.2, 8.1.3 and 8.1.4 and is defined by the approximate minimum search
distance adjusted as appropriate. When the AOC is defined by the approximate minimum search distance without adjustment, the
AOC is the default AOC.
3.2.4 biodegradation, n—process by which microbial organisms transform or alter (through metabolic, enzymatic, or other action)
the structure of chemicals present in the environment.
3.2.5 chemical(s) of concern, COC, n—chemical that is present in the subsurface environment, has a vapor pressure greater than
-5 3
1 mm of mercury, or a Henry’s Law Constant greater than 1×10 atm m /mole at ambient temperature and pressure, and can
potentially migrate as a vapor into the vadose zone of the TP.
3.2.5.1 Discussion—
COC generally meet specific criteria for volatility (see 3.2.39) and toxicity (see 3.2.34) and include volatile organic compounds,
semi-volatile organic compounds, petroleum hydrocarbons, and volatile inorganic analytes (such as mercury). A list of COC is
presented in Appendix X6. A chemical’s molecular weight has also been suggested as a criterion for volatility (with a threshold
of 200 g/mole). However, EPA indicated in its June 2015 Vapor Intrusion Guidance that it is not considering a chemical’s molecular
weight because molecular weight is only a weak predictor of volatility. Those chemicals with a molecular weight greater than 200
g/mole are identified with an asterisk in Appendix X6.
3.2.6 conduit, n—preferential pathway along which vapors released from contaminated soil and/or groundwater may migrate onto
the TP or away from the TP.
3.2.7 contaminant, n—any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air,
water, or soil.
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3.2.8 contaminated plume, n—plume in which concentrations of COC are known to be present in the soil or groundwater or both
at concentrations exceeding levels that generally would be the subject of an enforcement action if brought to the attention of
appropriate governmental agencies.
3.2.8.1 Discussion—
A contaminated plume can take the form of a groundwater contaminated plume or a soil contaminated plume. In a groundwater
contaminated plume,COC may be conveyed as solutes away from the point at which they were introduced into groundwater. They
move with the migrating groundwater mass in the direction of groundwater flow. When dispersion within the groundwater
contaminated plume brings a dissolved COC to the groundwater-soil gas interface, the COC may transition from the dissolved state
to the vapor state and migrate from groundwater into soil gas in the vadose zone. Once a COC migrates into soil gas in the vadose
zone, its migration may no longer be dependent on or related to groundwater movement. In a soil contaminated plume, COC
volatilized from the soil mix freely with soil gas that exists within soil voids in the vadose zone. COC in the soil gas can also be
introduced from underlying contaminated groundwater, as a result of a liquid spill into vadose zone soils, or by the direct release
of vapors from a leaking underground source. Migration of COC contaminated soil gas through the vadose zone may be in any
direction; however, it preferentially follows the path of least resistance. Fluctuations in barometric pressure may cause movement
of air and vapors into and out of the vadose zone through preferential pathways.
3.2.9 contaminated property, n—property on which soil or groundwater or both contains chemicals of concern (COC) or otherwise
hazardous substances at concentrations exceeding levels that generally would be the subject of an enforcement action if brought
to the attention of appropriate governmental agencies.
3.2.10 critical distance, n—defined in subsection 9.2.
3.2.11 dwelling, n—structure or portion thereof used for residential habitation.
3.2.12 environmental professional, n—person meeting the education, training, and experience requirements as set forth in 40 CFR
312.10(b), which is the requirement set forth in Practice E1527 (see subsection 3.3.5).
3.2.13 findings, n—defined in subsection 10.2.2.
3.2.14 fracture, n—break in a rock formation.
3.2.14.1 Discussion—
Faults, shears, joints, and planes of fracture cleavage are types of fractures. The presence of fractures may accelerate migration
of COCs along the fracture.
3.2.15 groundwater, n—water contained in the pore spaces of saturated geologic media.
3.2.16 Henry’s law, n—relationship between the partial pressure of a compound in air and the concentration of that compound in
water under equilibrium conditions; Henry’s law constants are temperature dependent.
3.2.17 hydrocarbon, n—chemical compound composed only of carbon and hydrogen atoms.
3.2.18 moisture content (of soil), n—amount of water lost from soil upon drying to a constant weight expressed as the weight per
unit weight of dry soil or as the volume of water per unit bulk volume of the soil.
3.2.18.1 Discussion—
For a fully saturated medium, moisture content expressed as a volume fraction equals the porosity.
3.2.19 nonaqueous phase liquid, NAPL, n—substances that do not dissolve readily in water and that remain in the original bulk
liquid form in the subsurface.
3.2.19.1 Discussion—
Light NAPL (LNAPL), such as gasoline, is less dense than water and can accumulate above the water table, while dense NAPL
(DNAPL), such as many chlorinated solvents, including trichloroethylene and perchloroethylene, are more dense than water and
can penetrate into the water table.
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3.2.20 permeability, n—qualitative description of the relative ease with which rock, soil, or sediment will transmit a fluid (that is,
a liquid or gas).
3.2.21 petroleum, n—crude oil or any fraction thereof that is liquid at standard conditions of temperature and pressure (60°F at
14.7 psia).
3.2.21.1 Discussion—
The term includes substances comprised of a complex blend of hydrocarbons derived from crude oil through the process of
separation, conversion, upgrading, and finishing, such as motor fuels, jet oils, lubricants, and petroleum solvents, and also includes
used oils.
3.2.22 petroleum hydrocarbon chemicals of concern, n—for the purpose of this guide, those volatile petroleum hydrocarbon
compounds are a subset of COC and readily biodegrade to carbon dioxide and water by soil microbes in aerated environments.
3.2.22.1 Discussion—
Petroleum hydrocarbon chemicals of concern may be present in several forms in environmental media, including adsorbed to soil,
as constituents of LNAPL above the water table, as dissolved solutes in groundwater, or as vapors in soil gas.
3.2.23 Phase I environmental site assessment, ESA, n—process described in Practice E1527.
3.2.24 porosity, n—volume fraction of a rock or unconsolidated sediment not occupied by solid material but usually occupied by
liquids, gas, and/or air.
3.2.25 preferential pathway, n—pathway that has the least amount of constraint on the migration of COC vapors.
3.2.25.1 Discussion—
Preferential pathways are natural or man-made and may provide direct contact between the subsurface of a property and the vapor
contaminant source (that is, the location on a property where the contaminated vapor intersects the preferential pathway). Natural
preferential pathways may include, for example, vertically fractured bedrock where the fractures are interconnected and in direct
contact with the subsurface of a property and the vapor contaminant source. Man-made preferential pathways may include, for
example, utility conduits and sewers. The presence of preferential pathways may also direct migrating COC vapors away from a
TP.
3.2.26 real estate, n—undeveloped real property, real property used for industrial, retail, office, agricultural, other commercial,
medical, or educational purposes, or property used as a single family or multi-family residential dwelling.
3.2.27 real estate transaction, n—transfer of title to or possession of real property or receipt of a security interest in real property.
3.2.28 report, n—document prepared by an environmental professional pursuant to Section 10.
3.2.29 saturated zone, n—zone in which all of the voids in the rock or soil are filled with water at a pressure that is greater than
atmospheric.
3.2.29.1 Discussion—
The water table is the top of the saturated zone in an unconfined aquifer.
3.2.30 semi-volatile organic compound, n—general term for an organic compound that has sufficient vapor pressure at standard
temperature (20°C) and pressure (1 atm) to vaporize (albeit at a slower rate than volatile organic compounds) and enter the
atmosphere.
3.2.31 solute, n—substance such as a contaminant that is dissolved in another substance such as groundwater.
3.2.32 target property, TP, n—property involved in the real estate transaction that is the subject of the VES defined by this guide.
3.2.33 toxic chemical, n—chemical whose vapor concentration of the pure component poses either an incremental lifetime cancer
risk (ILCR) or a non-cancer hazard quotient greater than acceptable values established by applicable federal, state, or local
regulatory agencies.
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3.2.34 toxicity, n—effect on human health that is exhibited by a toxic chemical; for the purposes of this guide, toxicity is defined
-6
as a chemical exhibiting an incremental lifetime cancer risk greater than 10 or a non-cancer Hazard Index greater than 1.
3.2.35 user, n—party who commissions the performance of a VES pursuant to this guide.
3.2.35.1 Discussion—
Commonly, the user is the prospective purchaser of a parcel of property.
3.2.36 vadose zone (or unsaturated zone), n—zone between the land surface and the water table within which moisture content
is less than saturation (except in the capillary fringe) and pressure is less than atmospheric.
3.2.36.1 Discussion—
Soil pore space typically contains air or other gases. The capillary fringe is included in the vadose zone.
3.2.37 vapor encroachment condition, VEC, n—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 (see Section
8) or Tier 2 (see Section 9) procedures in this guide.
3.2.37.1 Discussion—
Conditions may exist where there could be no vadose zone, such as the case of a building foundation sitting below the water table.
In this case, it may be possible for COC vapors to adversely impact the indoor air without migrating through a vadose zone.
3.2.38 volatile organic compound, VOC, n—general term for an organic compound that has sufficient vapor pressure (for example,
greater than 1 mm Hg) at standard temperature (20°C) and pressure (1 atm) to significantly vaporize and enter the atmosphere.
-5 3 -1
3.2.39 volatility, n—chemical is considered to be sufficiently volatile if its Henry’s law constant is greater than 10 atm-m -mol
and its vapor pressure is greater than 1 mm Hg at room temperature.
3.2.39.1 Discussion—
A chemical’s molecular weight has also been used as an indicator of volatility, with the threshold molecular weight being
approximately 200 g/mole. EPA in its June 2015 Vapor Intrusion Guidance does not use the molecular weight criterion because
this criterion is believed to be only a weak predictor of volatility.
3.2.40 water table, n—top of the saturated zone in an unconfined aquifer.
3.3 Practice E1527 Terms Used in This Guide—Some terms have been modified to be consistent with this guide.
3.3.1 adjoining properties, n—any real property or properties the border of which is contiguous or partially contiguous with that
of the target property, or that would be contiguous or partially contiguous with that of the target property but for a street, road,
or other public thoroughfare separating them.
3.3.2 business environmental risk, n—risk that can have a material environmental or environmentally driven impact on the
transaction or the business associated with the current or planned use of a parcel of real estate, not limited to environmental issues
that are investigated pursuant to this guide. Consideration of business environmental risk issues may involve addressing one or
more non-scope considerations, some of which are identified in Section 11 of this guide.
3.3.3 Comprehensive Environmental Response, Compensation, and Liability Information System (CERCLIS), n—list of sites
compiled by EPA that EPA has investigated or is currently investigating for potential hazardous substance contamination and for
possible inclusion on the National Priorities List (the CERCLIS information system supporting CERCLA has been retired by EPA
and replaced by SEMS, the Superfund Enterprise Management System).
3.3.4 CORRACTS list, n—list of hazardous waste treatment, storage, or disposal facilities and other RCRA-regulated facilities
(because of past interim status or storage of hazardous waste beyond 90 days) that have been notified by the EPA to undertake
corrective action under RCRA. The CORRACTS list can be derived from the EPA database that manages RCRA data.
3.3.5 environmental professional, n—person meeting the education, training, and experience requirements as set forth in 40 CFR
312.10(b). The person may be an independent contractor or an employee of the user.
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3.3.6 environmental site assessment, ESA, n—process by which a person or entity seeks to determine if a particular parcel of real
property (including improvements) is subject to recognized environmental conditions (see subsection 3.3.22).
3.3.7 fire insurance maps, n—maps produced for private fire insurance map companies that indicate uses of properties at specified
dates and that encompass the property. These maps are often available at local libraries, historical societies, private resellers, or
from the map companies who produced them.
3.3.8 hazardous substance, n—substance defined as a hazardous substance pursuant to CERCLA 42 U.S.C. 9601(14), as
interpreted by EPA regulations and the courts.
3.3.9 hazardous waste, n—any hazardous waste having the characteristics identified under or listed pursuant to Section 3001 of
RCRA, as amended (42 U.S.C. 6921) (but not including any waste the regulation of which under RCRA (42 U.S.C. 6901-6992k)
has been excluded by Act of Congress). RCRA defines a hazardous waste, at 42 U.S.C. 6903, as: “a solid waste, or combination
of solid wastes, which because of its quantity, concentration or physical, chemical or infectious characteristics may (A) cause, or
significantly contribute to an increase in mortality or an increase in serious irreversible or incapacitating reversible illness; or (B)
pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported or
disposed of, or otherwise managed.”
3.3.10 landfill, n—place, location, tract of land, area, or premises used for the disposal of solid wastes as defined by state solid
waste regulations. The term is synonymous with the term solid waste disposal site and is also known as a garbage dump, trash
dump, or similar term.
3.3.11 local government agencies, n—those agencies of municipal or county government having jurisdiction over the target
property. Municipal and county government agencies include but are not limited to cities, parishes, townships, and similar entities.
3.3.12 local street directories, n—directories published by private (or sometimes government) sources that show ownership,
occupancy, and/or use of sites by reference to street addresses. Often local street directories are available at libraries, or historical
societies, and/or local municipal offices.
3.3.13 National Priorities List, NPL, n—list compiled by EPA pursuant to CERCLA 42 U.S.C. §9605(a)(8)(B) of properties with
the highest priority for cleanup pursuant to EPA’s Hazard Ranking System. See 40 C.F.R. Part 300.
3.3.13.1 Discussion—
The CERCLIS information system supporting CERCLA has been retired by EPA and replaced by SEMS, the Superfund Enterprise
Management System.
3.3.14 obvious, adv—that which is plain or evident; a condition or fact that could not be ignored or overlooked by a reasonable
observer while visually or physically observing the property.
3.3.15 occupants, n—those tenants, subtenants, or other persons or entities using a property or a portion of the property.
3.3.16 operator, n—person responsible for the overall operation of a facility.
3.3.17 owner, n—generally the fee owner of record of the property.
3.3.18 petroleum products, n—those substances included within the meaning of the petroleum exclusion to CERCLA, 42 U.S.C.
§9601(14), as interpreted by the courts and EPA, that is: petroleum, including crude oil or any fraction thereof which is not
otherwise specifically listed or designated as a hazardous substance under Subparagraphs (A) through (F) of 42 U.S.C. §9601(14),
natural gas, natural gas liquids, liquefied natural gas, and synthetic gas usable for fuel (or mixtures of natural gas and such synthetic
gas). (The word fraction refers to certain distillates of crude oil, including but not limited to gasoline, kerosene, diesel oil, jet fuels,
and fuel oil, pursuant to Standard Definitions of Petroleum Statistics. )
Standard Definitions of Petroleum Statistics, American Petroleum Institute, Fourth Edition, 1988.
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3.3.19 publicly available, adj—information that is publicly available means that the source of the information allows access to the
information by anyone upon request.
3.3.20 practically reviewable, adj—information that is practically reviewable means that the information is provided by the source
in a manner and in a form that, upon examination, yields information relevant to the property without the need for extraordinary
analysis of irrelevant data. The form of the information should be such that the user can review the records for a limited geographic
area. Records that cannot be feasibly retrieved by reference to the location of the property or a geographic area in which the
property is located are not generally practically reviewable. Most databases of public records are practically reviewable if they can
be obtained from the source agency by the county, city, zip code, or other geographic area of the facilities listed in the record
system. Records that are sorted, filed, organized, or maintained by the source agency only chronologically are not generally
practically reviewable. Listings in publicly available records that do not have adequate address information to be located
geographically are not generally considered practically reviewable.
3.3.21 reasonably ascertainable, adj—information that is (1)publicly available,(2) obtainable from its source within reasonable
time and cost constraints, and (3) practically reviewable.
3.3.22 recognized environmental condition, REC, n—(1) the presence of hazardous substances or petroleum products in, on, or
at the subject property due to a release to the environment; (2) the likely presence of anyhazardous substances or petroleum
products in, on, or at a property: the (1)subject property due to any release to the environment; a (2)release under conditionsor
likely indicative of a release to the environment;environment; or (3) the presence of hazardous substances or petroleum products
in, on, or at the subject property under conditions that pose a material threat of a future release to the environment.
3.3.22.1 Discussion—
For the purposes of this definition, “likely” is that which is neither certain nor proved, but can be expected or believed by a
reasonable observer based on the logic and/or experience of the environmental professional, and/or available evidence, as stated
in the report to support the opinions given therein.
3.3.22.2 Discussion—
de minimis conditions—The REC term is not intended to include de minimis conditions that generally do not present a material
risk of harm to public health or the environment and that generally would not be the subject of an enforcement action if brought
to the attention of appropriate governmental agencies. Conditions determined to be de minimis are not RECs.
3.3.23 records review, n—that part that is contained in Section 8 of this guide that addresses which records should or may be
reviewed.
3.3.24 solid waste disposal site, n—place, location, tract of land, area, or premises used for the disposal of solid wastes as defined
by state solid waste regulations. The term is synonymous with the term landfill and is also known as a garbage dump, trash dump,
or similar term.
3.3.25 solvent, n—chemical compound that is capable of dissolving another substance and may itself be a hazardous substance,
used in a number of manufacturing/industrial processes including but not limited to the manufacture of paints and coatings for
industrial and household purposes, equipment clean-up, and surface degreasing in metal fabricating industries.
3.3.26 standard environmental record sources, n—those records specified in subsection 8.1.3 of this guide.
3.3.27 standard historical sources, n—those sources of information about the history of uses of a property as specified in
subsection 8.4 of this guide.
3.4 Acronyms:
3.4.1 AOC—Area of concern
3.4.2 CERCLA—Comprehensive Environmental Response, Compensation and Liability Act of 1980 (as amended, 42 U.S.C.
§§9601 et seq.)
3.4.3 CFR—Code of Federal Regulations
E2600 − 22
3.4.4 COC—Chemical(s) of concern
3.4.5 DNAPL—Dense nonaqueous phase liquid (a separate phase groundwater contaminant that is both denser than water and its
concentration exceeds its solubility in water)
3.4.6 EPA—United States Environmental Protection Agency
3.4.7 ESA—Environmental site assessment
3.4.8 LNAPL—Light nonaqueous phase liquid (a separate phase groundwater contaminant that is less dense than water and its
concentration exceeds its solubility in water)
3.4.9 NAPL—Nonaqueous phase liquid
3.4.10 NPL—National Priorities List
3.4.11 REC—Recognized environmental condition
3.4.12 TP—Target property
3.4.13 USC—United States Code
3.4.14 USGS—United States Geological Survey
3.4.15 VEC—Vapor encroachment condition
3.4.16 VES—Vapor encroachment screen
3.4.17 VOC—Volatile organic compound
4. Significance and Use
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 a Practice 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 PracticeE1527 E1527 Phase I ESA—This guide,practice, when used in conjunction with Practice
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.
E2600 − 22
4.2.2 Independent Use—This guide may be used independent of a Practice 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 Practice 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
induring 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;
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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.
5. Relationship to Practice E1527 Phase I ESA
5.1 Identification of a REC Pursuant to a Phase I ESA—RECs are identified only through the performance of a Practice an E1527
Phase I ESA. Thus, a finding pursuant to this guide that a VEC exists at the TP is not a determination that a REC exists at the TP.
Whether a REC exists at a TP as a result of the impact of possible vapor migration into the vadose zone of the TP is a separate
determination to be made by the environmental professional pursuant to Practice E1527. This guide does not constitute or meet
the requirements for conducting “all appropriate inquiry” or any part of “all appropriate inquiry” as defined by U.S. EPA under
CERCLA and the regulations there under, including 40 CFR Sec. 312.11.
5.2 VES—The VES established by this guide is intended to be used independently of or in conjunction with Practice E1527 Phase
I ESA.
5.2.1 The VES may be conducted concurrently with the Practice E1527 Phase I ESA.
5.2.2 The VES may be conducted independent of a Practice an E1527 Phase I ESA. When conducting a VES pursuant to this guide,
the data collection actions specified in this guide should be implemented (see subsection 5.3 and Section 8).
5.3 Use of Information Collected in a Phase I ESA Conducted in Accordance with the Practice E1527 Standard—The screening
(see Section 8) identified in this guide makes use of information similar to information generally collected as part of a Practice
an E1527 Phase I ESA as well as additional information described below and in Section 8 of this guide. The information that should
be collected includes, but is not limited to, federal, state, local, and tribal government records, chemical use and historical records
of prior uses on the TP and within the AOC surrounding the TP as determined by the procedures set out in Section 8, soil
characteristics, geological characteristics, contaminant characteristics
...