Vapor Encroachment Screening (VES)
and Vapor Intrusion (VI) Assessment
What the difference is, and why lawyers,
bankers, regulators, and the regulated
community should care
Steve Crider
May 7, 2014
News articles
Acronym list
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AOC:
VES:
VEC:
VI:
TP:
COC:
LNAPL:
DNAPL:
EP:
area of concern
vapor encroachment screen
vapor encroachment condition
vapor intrusion
target property
chemical of concern
light nonaqueous-phase liquids
dense nonaqueous-phase liquids
environmental professional
Vapor encroachment and the
vapor intrusion assessment process
• Are there actual or potential volatile vapors
encroaching on the target property (TP)? (addressed by
ASTM E 2600-10)
• If so, can these vapors migrate into structures on the
property?
(addressed by federal/state VI guidance)
• If so, can they represent an indoor air-quality
problem?
(addressed by federal/state VI guidance)
Informal survey: consultants and the
vapor pathway
• MDEQ has focused on VI, May 2013 published a
guidance document; ASTM updated Phase I ESA
standard practice which now specifically mentions
vapor, so are we, consultants, doing any better?
• Not yet
− BEAs still targeting soil and groundwater
− Vapor typically an afterthought during due-care planning
process, resulting in:
• Insufficient or no vapor data
• Presumptive remedies
− Of the five BEAs on desks of district staff, only one
mentions vapor assessment in Phase I ESA
Root cause(s)???
• Cost and time to conduct soil-gas sampling
• Soil gas not its own criteria; SVIIC and GVIIC not
typically facility status drivers
• Vapors not thoroughly assessed or considered in
Phase I ESA process
Using ASTM E2600-10 or an alternative
• If a company develops its own methodology, it must
be well enough documented in the Phase I ESA to
allow a third party to reconstruct the analysis
• Advantages of using Tier 1 in ASTM E2600-10
− Methodology standardized through ASTM consensus
process
− Developed by industry VI experts
− Ability to use (without further documentation) critical
distances in E2600-10
− Reduced liability
ASTM E2600-10: overview
• NOT A REQUIREMENT FOR ASTM 1527-13
• Standard guide not standard practice
• Focused solely on likelihood of migrating vapors to
encroach on TP (creating a vapor encroachment
condition, or VEC)
ASTM E2600-10: purpose
• Provide practical guidance and useful process for
conducting a vapor encroachment screen (VES) on a
property parcel involved in a real estate transaction in
the U.S. with respect to chemicals of concern (COCs)
that may migrate as vapors onto a property as a result
of contaminated soil and groundwater on or near the
property
ASTM E2600-10: objective
• Whether or not encroaching vapors result in intrusion
requires investigation beyond scope of standard
• Objective: identify VECs, analogous to identifying
Recognized Environmental Conditions in ASTM E1527
ASTM E2600-10: summary
• Two levels of screening for VECs:
− Tier 1: focuses on known or suspected contaminated sites
in AOC as identified in ASTM E1527 investigations
(government records investigation, historical research, etc.)
− Tier 2: focuses on plumes from any contaminated sites in
AOC and their proximity (critical distance) to TP, or actual
sampling to identify if vapors have encroached on TP
ASTM E2600-10: additional terminology
• Vapor encroachment condition (VEC)
• Area of concern (AOC)
• Critical distance
ASTM E2600-10: vapor encroachment condition
• Actual or likely presence of COC vapors in subsurface
of TP, caused by release of vapors from contaminated
soil or groundwater on or near TP
ASTM E2600-10: area of concern
• Measured from TP boundary to known or suspected
contaminated property
• 1/3 mile for known or suspected contaminated sites
with COCs (volatile or semivolatile hazardous
substances)
• 1/10 mile for known or suspected contaminated sites
with petroleum hydrocarbon COCs
• May be reduced in cross-gradient and side-gradient
direction if groundwater flow direction is known
ASTM E2600-10: critical distance
• Defined as distance from nearest edge of
contaminated plume to nearest TP boundary
• Measured linearly in any direction: horizontal,
vertical, etc.
• 100 ft. for COCs
• 30 ft. for dissolved volatile petroleum hydrocarbons
• 100 ft. for petroleum LNAPL accumulating above
water table
• What about DNAPL?: treat as COC
ASTM E2600-10: methodology
• Getting down to business
ASTM E2600-10: Tier 1 initial screening for VECs
• Designed as screening step to supplement Phase I ESA;
relies on information already collected in investigation
• Review of governmental and historical records at
specific search distances to identify COC-contaminated
properties within AOC
− 1/3 mile for known or suspected contaminated sites with
COCs (volatile or semivolatile hazardous substances)
− 1/10 mile for known or suspected contaminated sites with
petroleum hydrocarbon COCs
ASTM E2600-10: most prevalent sources of
concern
• Present and former:
− Gas stations and auto repair sites
− Scrap-metal sites
− Manufactured gas plant sites
− Dry-cleaning sites
− Industrial sites, particularly those using chlorinated solvents
for degreasing and parts cleaning
− Municipal solid waste landfills and open dumps
− Hazardous-waste disposal sites
ASTM E2600-10: Tier 1 AOC when groundwater
flow direction can be estimated
• Upgradient
− 1/3 mile for COC sources
− 1/10 mile for petroleum hydrocarbon sources
• Downgradient
− 100 ft. for COC sources/petroleum hydrocarbon LNAPL sources
− 30 ft. for dissolved petroleum hydrocarbon sources
• Cross-gradient
− 100 ft. for COC sources/petroleum hydrocarbon LNAPL sources +
plume-width consideration
− 30 ft. for dissolved petroleum hydrocarbon sources +
plume-width consideration
ASTM E2600-10: net reduction in AOC for Tier 1
screening of known or suspected petroleum sources
Source location
E2600-10
E2600-10 w/ Buonicore
methodology*
Upgradient
528 ft.
528 ft.
Downgradient
528 ft.
100 ft. (LNAPL)
30 ft. (dissolved)
Cross-gradient
528 ft.
165 ft. (LNAPL)
95 ft. (dissolved)
* Buonicore, A.J., Screening for Potential Vapor Intrusion Problems, Paper #129, Proc.
AWMA 102nd Annual Conference , Detroit, MI, June 16–19, 2009, and Buonicore, A.J.,
Methodology for Identifying the Area of Concern Around a Property Potentially
Impacted by Vapor Mitigation from Nearby Contaminated Sources, Paper No. 2011-A301, Proceedings, AWMA 104th Annual Meeting in Orlando, FL, June 20–24, 2011
ASTM E2600-10: net reduction in AOC for Tier 1
screening of known or suspected COC sources
Source location
E2600-10
E2600-10 w/ Buonicore
methodology*
Upgradient
1,760 ft.
1,760 ft.
Downgradient
1,760 ft.
100 ft.
Cross-gradient
1,760 ft.
365 ft.
* Buonicore, A.J., Screening for Potential Vapor Intrusion Problems, Paper #129, Proc.
AWMA 102nd Annual Conference , Detroit, MI, June 16–19, 2009, and Buonicore, A.J.,
Methodology for Identifying the Area of Concern Around a Property Potentially
Impacted by Vapor Mitigation from Nearby Contaminated Sources, Paper No. 2011-A301, Proceedings, AWMA 104th Annual Meeting in Orlando, FL, June 20–24, 2011.
EDR VEC app
EDR VEC app (cont.)
EDR VEC app (cont.)
ASTM E2600-10: EP judgment
• Type of TP
• Location of contamination source
• Cleanup status of contaminated site
• Depth to groundwater
• Soil characteristics
• Presence of “vapor conduits” (MDEQ favorite)
• Presence of hydraulic or physical barriers
ASTM E2600-10: Tier 1 conclusions
1. A VEC exists (physical evidence)
2. A VEC likely exists (within close proximity, e.g., two
properties?)
3. A VEC cannot be ruled out (further away, beyond
two properties?)
4. VEC can be ruled out because it does not or is not
likely to exist (you are done!!)
ASTM E2600-10: Tier 1 conclusions (cont.)
• If 1, 2, or 3, determine if VEC is a REC if done in
conjunction with Phase I ESA
• “De minimis” (?)
• Apply state VI guidance criteria (?)
• Other (?)
• If 1, 2, or 3, EP and user decide whether further
investigation (such as proceeding to Tier 2 or state
program) is warranted
ASTM E2600-10: Tier 2 more refined screening
• Non-invasive
− If Phase II data on contaminated source exist, proximity of
contaminated plume to TP is evaluated
− Plume test / critical-distance evaluation
ASTM E2600-10: Tier 2 more refined screening
Critical Distance
100 ft for NAPL COCs
30 ft for Dissolved Petro
Critical Distance
• TP Property Boundary
• Existing or proposed
building
• Vapor Conduits
ASTM E2600-10: Tier 2 invasive
• Invasive (soil, groundwater or soil gas sampling)
− If Phase II data on contaminated source does NOT exist, or
− If preferential pathway exists (natural or constructed), or
− If VEC is identified in Tier 1 and you want to do
confirmatory sampling (follow state program), or
− If client or lender is more comfortable with sampling
(follow state program).
• Sampling can be done at the TP boundary to identify
whether vapors are encroaching on TP
− Plume test / critical-distance evaluation
ASTM E2600-10: Tier 2 conclusions
1. VEC exists (physical evidence)
2. VEC likely exists (within close proximity, e.g., two
properties?)
3. VEC cannot be ruled out (further away, beyond two
properties?)
4. VEC can be ruled out because it does not or is not
likely to exist (you are done!!)
ASTM E2600-10: Tier 2 conclusions (cont.)
• If 1, 2, or 3 then determine if VEC is a REC if done
in conjunction with a Phase I ESA
− “De minimis” (?)
− Apply state VI guidance criteria (?)
− Other (?)
• If 1, 3, or 3, EP and user decide whether further
investigation (such as state program) is warranted
Why do we care about E2600-10 if it’s not part
of a Phase I ESA?
• ASTM E1527-13 Section 3.2.56 lists term VAPOR—
so EP must consider it during Phase I ESA
• ASTM E2600 and Buonicore method provide hard
numbers to rely on for determining REC or no REC
• Gut feelings are great, but having data to support
your position helps lawyers sleep at night
Why do I care about E2600-10 if it’s not part of
a Phase I ESA? (cont.)
• Both ASTM E1527-13 and E2600-10 rely on
EP’s professional judgment, so ultimately it’s
still up to you
• Using guidance in E2600-10 does not mean you
have to write a full report…
Scope of work: Tier I
• Add-on to Phase I ESA
− Modified questionnaire (see Appendix 3)
− Report format follows 1527 so you need to add only
subsections that discuss vapor in “records review, findings,
opinions, and conclusions” section of report
Scope of work: Tier 2
• Non-intrusive
− More extensive file review of State/Local records
− Letter-style report documenting reports reviewed and
plume distances measured to nearest TP boundary (the
critical-distance assessment)
• Intrusive sampling
− Follow state guidelines
Final thoughts
• Not required for ASTM E 1527-13,
but a useful guide!