Myths and Misconceptions about Screening for Vapor Migration in Phase Is

Misconceptions with Vapor Migration
Screening using ASTM E 2600-10 in a
Phase I
by

Anthony J. Buonicore, P.E., DEE, QEP
CEO, The Buonicore Group
Chairman, ASTM Vapor Intrusion Task Group

for presentation at

EDR Due Diligence at Dawn Seminar
Spring 2012

Overview

 Top 10 Misconceptions about E 2600-10
 Suggested Steps for Conducting a Tier 1 VEC
Screen as part of a Phase I
 Considerations in Making a VEC-REC
Determination

Misconception #1

“Vapor migration screening is not
part of a Phase I unless the client
asks for it or the state where the
property is located has vapor
intrusion regulations. Moreover,
E 2600-08 says it is optional.”

WRONG!
 E 2600-08 has been superceded by E 2600-10
 CERCLA definition of release of hazardous
substances includes “emitting” and “escaping” into
the environment (which includes “into subsurface
strata.”
 AAI Rule says EP must provide “an opinion as to
whether the inquiry has identified conditions
indicative of releases or threatened releases of
hazardous substances…on, at, in or to the property.”

WRONG!
 ASTM E 1527 definition of a REC includes “presence or
likely presence of any hazardous substances or petroleum
products…indicate an existing release, a past release or a
material threat of a release…into structures…into the
ground…”
 CERCLA, AAI and the REC definition do not differentiate
“releases” by media, i.e., solid, liquid or vapor.
 E 1527 is currently being revised to clarify that vapor
migration must be treated no differently than contaminated
groundwater migration in a Phase I…

E 1527 Ballot Revisions Clarifying that Vapor Migration is to
be Treated No Differently than Contaminated Groundwater
Migration
 CERCLA definitions of “release” and “environment” added
 E 2600-10 specifically referenced in Documents Section
 Definition of “migration” added: “movement of hazardous substances
or petroleum products in any form, including solid and liquid at the
surface or subsurface, and vapor in the subsurface” and specifically
mentioned in a number of sections in the standard
 Regulatory agency files should be reviewed if the property or
adjoining identified in records research if EP judges that it is
warranted – would assist in evaluating potential impact of vapor
migration from nearby sites that have been “remediated” without
vapor pathway considered
 Non-scope considerations – Indoor Air Quality – clarified to say
“unrelated to releases of hazardous substances or petroleum products

Misconception #2

“ The REC definition includes
releases or threatened releases
“into structures” on the property.
This mean that vapor intrusion
into structures needs to be
evaluated in an ASTM E 1527
Phase I.”

WRONG!
 Vapor intrusion assessment involves an indoor air quality
evaluation. E 1527 specifically identifies indoor air quality as
a “non-scope consideration” in a Phase I.
 If a VEC exists or is likely or cannot be ruled out, and the
EP determines that it represents a REC in the Phase I, a
follow-on investigation can be conducted to evaluate the
potential for vapor intrusion.
 If it is determined that a VEC can be ruled out because it
does not exist or is unlikely to exist, then the issue of
whether vapors may intrude into structures on the property
is moot.

Misconception #3

“ If a VEC exists or is likely to
exist, there is no way to close a
deal without an extensive site
investigation that will probably
kill the deal.”

WRONG!
 If a VEC exists or is likely to exist or cannot be ruled out,
the deal can still be closed by doing “pre-emptive
mitigation.”
 Since vapor intrusion mitigation measures can be estimated
reasonably accurately (generally in the $2 – $7/SF range,
depending on mitigation measure), this cost can be used to
adjust the deal price similar to the way that the presence of
asbestos has been used to adjust the deal price (since
asbestos removal costs can also be estimated reasonably
accurately).
 The cost to pre-emptively mitigate can be much less than
the cost to conduct a VI site investigation to determine if a

Misconception #4

“Both Tier 1 and Tier 2
screening in E 2600-10 must be
conducted to evaluate vapor
migration.”

WRONG!
 Tier 1 was designed as the methodology for
vapor migration evaluation in a Phase I.
 If a VEC exists or is likely or cannot be
ruled out based upon the Tier 1 evaluation,
Tier 2 was designed as the suggested follow-
up (effectively equivalent to a “vapor” Phase
II).

Misconception #5
“Using the distances specified in
Tier 1 to identify the area of
concern results in too many sites
that need evaluating. This can
take significant time.”

WRONG!
 The Tier 1 distances for the AOC are just the
starting point. They conservative and represent 90th
percentile plume lengths and widths!
 The EP can reduce the Tier 1 distances significantly
using professional judgment, e.g., with respect to
groundwater flow direction, soil characteristics,
intercepting utility corridors, etc.
 When the AOC is minimized using professional
judgment, there will be far fewer sites that need to
be evaluated further.

Misconception #6

“All VECs are RECs.”

WRONG!
 Only for HUD multifamily Phase Is!
(Note: HUD projects involve residential properties where
virtually all the vapor intrusion litigation can be found.)
 More often than not, VECs will not be RECs.
 More often than not, a known or suspect contaminated
site (with potential vapor migration) located nearby
and up-gradient from the TP would have been judged
a REC anyway from a groundwater migration
viewpoint (irrespective of the additional concern over
vapor migration).
 More on this later!

Misconception #7

“Vapor migration analysis need
only be performed on RECs since
a VEC would have been a REC
anyway.”

WRONG!
 If vapor migration evaluations are only performed on RECs, then
the implicit assumption is that only contaminated groundwater
migration will be considered to determine if there is a REC. This
will eliminate conditions that become RECs solely because of the
potential for vapor migration.
For example…
 If vapor migration is not being considered, a down-gradient nearby
(but not adjacent) dry cleaner would not likely be considered a REC
since the contaminated groundwater plume would be moving away
from the TP. However, today it may be considered a REC solely
based upon vapor migration potential (vapor migration does not
have to follow groundwater direction, but rather the path of least
resistance which can be opposite groundwater flow direction).

Misconception #8
“There is no guidance on evaluating
VECs to determine if they are
RECs.”

-

7

WRONG!
 The best guidance is the REC definition
itself and specifically the de minimis
definition
 Two conditions for de minimis

- not a threat to human health and the environment AND
- would not be subject of an enforcement action if brought
to the attention of appropriate government agencies
 De minimis conditions are not RECs
 More on this later!

Misconception #9

“The future use of a property is
not taken into consideration in
E 2600-10.”

WRONG!
 For Tier 1 screening, distances are
measured from a known or suspect
contaminated site to the target property
boundary
 If vapors are likely to penetrate the
property boundary, then a VEC is likely
irrespective of the status of the property
 Future use comes into play more often
than not with determining if the VEC is a
REC

Misconception #10

“E 2600-10 conflicts with state vapor
intrusion guidance.”

WRONG!
 State guidance focuses on vapor intrusion assessment
(and vapor migration from the source of contamination –
could be from the edge of a contaminated soil or
groundwater plume - to the building)
 E 2600-10 focuses on the potential for vapors to encroach
upon the property, i.e., vapor migration from a known or
suspect contaminated site to encroach upon the TP
boundary
 E 2600-10 complements state guidance in that it
effectively acts as a screening tool
 If a VEC exists or is likely or cannot be ruled out, state
guidance can assist in determining if the VEC is a REC

The jury is still out on…
“Dealing with nearby remediated/closed/NFA sites
where vapor pathway was NOT taken into
consideration.”
Is it necessary to review the regulatory files?

E 1527 Task Group has proposed for the 2013 revision to
require the EPs to review pertinent regulatory files on nearby
properties that in their judgment have the potential to impact
the target property!

Suggested Steps for Conducting a
Tier 1 VEC Screen
(assuming no preferential pathways direct to the TP from contaminated sites)

1. Identify AOC and minimize to the maximum
extent possible based on experience

● Start out with 1/3rd mile or 1/10th mile (for petroleum hydrocarbons), BUT
● Can reduce significantly when GW flow direction known or can be inferred
(from topographical data or nearby Phase II data or hydrologic data, etc.)
● Can further reduce by using professional judgment based on local knowledge
● Hydraulic barriers (such as rivers and wetlands)
● Sub-surface man-made physical barriers (preventing vapors
from reaching TP such as utility lines in a main road that can intercept
migrating vapors moving toward a TP)
● Sub-surface natural barriers (preventing vapors from reaching the TP
such as confining layers, e.g., low permeability soil (e.g., clay layer) or
fresh water lens

Net Reduction in AOC for Tier 1 Screening of
Known or Suspect COC SOURCES

E 2600-10 w/
Source Location E 2600-10 Buonicore Methodology*
Up-gradient 1,760’ 1,760’

Down-gradient 1,760’ 100’

Cross-gradient 1,760’ 365’

* Buonicore, A.J. , Methodology for Identifying the Area of Concern Around a Property Potentially Impacted by Vapor Migration
from Nearby Contaminated Sources, Paper No. 2011-A-301, Proceedings, Air & Waste Management Association, 104th Annual
Sources, Proceedings,
Meeting, Orlando, Florida, June 20-24, 2011.

Net Reduction in AOC for Tier 1 Screening of
Known or Suspect PHC SOURCES
E 2600 Revised w/
Source Location E 2600-08 Buonicore Methodology*
Up-gradient 528’ 528’

Down-gradient 528’ 100’ (LNAPL)
30’ (dissolved)

Cross-gradient 528’ 165’ (LNAPL)
95’ (dissolved)
* Buonicore, A.J. , Methodology for Identifying the Area of Concern Around a Property Potentially Impacted by Vapor Migration
from Nearby Contaminated Sources, Paper No. 2011-A-301, Proceedings, Air & Waste Management Association, 104th Annual
Sources, Proceedings,
Meeting, Orlando, Florida, June 20-24, 2011.

Conducting a Tier 1 VEC Screen cont’d

2. Are there any known or suspect COC-
contaminated sites in the EP-defined AOC?
● Government records
● Historical research
● Other (?)

3. Evaluate each site remaining in the EP-defined AOC
● Remediation status?
● Did remediation consider vapor pathway?
● Review AULs – contamination left on-site?
● Other (?)


4. Identify VEC status
● exists (physical evidence)
● likely (within close proximity, e.g., two properties?)
● can not be ruled out (further away, beyond two
properties?)
● can be ruled out because it does not or is unlikely
to exist
5. If VEC can be ruled out, vapor migration evaluation is
completed

6. If VEC exists/likely/cannot be ruled out,
determine if VEC is a REC
● “De minimis” (?)
● Apply state VI guidance criteria (?)
● Other (?)

7. If VEC is a REC, E 2600-10 Tier 2 provides a
suggested vapor migration scope-of-work for follow-
on investigation in Phase II (may also be part of a Phase
II investigation into potential groundwater
contamination)

Considerations in Making a
VEC-REC Determination

Considerations

 What is the depth to contaminated groundwater?
For example, VEC may exist or be likely because of
groundwater contamination on or near the TP, but a REC (due
to vapor migration) may not exist (under the de minimis
condition clause) because the depth to groundwater may be greater
than the applicable ASTM critical distance or distance identified
in state VI guidance. [Of course, the presence of contaminated
groundwater in and of itself may result in a REC anyway.]

Considerations cont’d
 Where is the nearest structure on the TP with
respect to the contaminant plume? For example,
VEC may exist or be likely because of groundwater
contamination on or near the TP, but a REC (due to vapor
migration) may not exist (under the de minimis condition clause)
because the distance between the structure and the edge of the
contaminated plume may be greater than the distance specified in
state VI guidance. [Of course, the presence of contaminated
groundwater in and of itself may result in a REC anyway.]

For example…
● NJDEP VI Guidance: distance horizontally or vertically
between the nearest edge of the contaminated
groundwater plume and the nearest structure on the TP,
equal to

●100’ for COC or LNAPL PHC-COC
● 30’ for Dissolved PHC-COC

For example…
● State of Colorado is concerned when:
● Building “directly over or immediately adjacent
to a subsurface source of contamination”
● Building “within one or two properties of the
plume boundary or approximately 100 ft.”

● Colorado Indoor Air Guidance, September 2004: distance
horizontally or vertically between the nearest edge of the
contaminated groundwater plume and the nearest structure on the
TP, equal to
● 100’ for COC or LNAPL PHC-COC

 What is the contaminant concentration? For
example, a VEC may exist or be likely because of groundwater
contamination on or near the TP, but a REC (due to vapor
migration) may not exist (under the de minimis condition clause)
because the volatile contaminant concentration is below the state
risk screening level for groundwater. [Of course, the presence of
contaminated groundwater in and of itself may result in a
REC anyway.]

 How has the structure on the TP been designed? For
example, a VEC may exist or be likely because of groundwater
contamination on or near the TP, but a REC (due to vapor migration)
may not exist (under the de minimis condition clause) because the structure
has been designed to be intrinsically safe from chemical vapor intrusion,
i.e., no vapor pathway to potential human receptors. Examples might
include a building designed to operate 100% of the time under positive
pressure, or condos with open-air parking directly below the units, or
buildings with radon mitigation systems. [Of course, the presence of
contaminated groundwater in and of itself may result in a REC
anyway.]

Where are there more likely to be
RECs based solely on vapor migration
considerations?
 Down-gradient known or suspect contaminated
sites
 Cross-gradient known or suspect contaminated
sites
 Vapor migration takes the path of least resistance
no matter what direction it is!

Where is it more likely that what
caused a VEC would have been
viewed as a REC anyway even if
vapor migration was not considered?

 Up-gradient known or suspect contaminated sites

VEC-REC determination is impacted by:
 State VI Guidance and E 1527-05 de
minimus criteria in REC definition
 Soil characteristics, subsurface confining
layers and depth to water table
 Hydraulic barriers
 Physical barriers
 Building design and location on property
 Building operation

Bottom Line
 EP must consider vapor migration no differently than the
way contaminated groundwater migration is considered in a
Phase I
 EP can evaluate vapor migration using whatever
methodology the EP determines to be appropriate (if not E
2600-10, then EP needs to document “alternative”
methodology and include documentation in the Phase I)
 E 2600-10 Tier 1 screening methodology is an industry
consensus methodology
 E 2600-10 allows for EPs professional judgment and is
therefore able to “cover” virtually any “alternative” vapor
migration methodology (making a strong case for using E 2600-10)

Bottom Line
 If E 2600-10 Tier 1 screening indicates a VEC, EP must
then decide as part of Phase I if VEC constitutes a REC
- RECs can only be identified through the ASTM
E 1527-05 standard practice
- RECs do not include de minimis conditions

 E 2600-10 Tier 2 provides a suggested follow-on
investigation of a Tier 1 VEC

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