1. 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

2. News articles

3. Acronym list AOC: area of concern VES: vapor encroachment screen
VEC: vapor encroachment condition
VI: vapor intrusion
TP: target property
COC: chemical of concern
LNAPL: light nonaqueous-phase liquids
DNAPL: dense nonaqueous-phase liquids
EP: environmental professional

4. 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 )
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)

5. 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

6. 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

7. 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 E
Methodology standardized through ASTM consensus process
Developed by industry VI experts
Ability to use (without further documentation) critical distances in E
Reduced liability

8. ASTM E : overview
NOT A REQUIREMENT FOR ASTM
Standard guide not standard practice
Focused solely on likelihood of migrating vapors to encroach on TP (creating a vapor encroachment condition, or VEC)

9. ASTM E : 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

10. ASTM E : 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

11. Two levels of screening for VECs:
ASTM E : 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

12. ASTM E2600-10: additional terminology
Vapor encroachment condition (VEC)
Area of concern (AOC)
Critical distance

13. 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

14. 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

15. 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

16. ASTM E : methodology
Getting down to business

17. 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

18. 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

19. 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

20. ASTM E2600-10: net reduction in AOC for Tier 1 screening of known or suspected petroleum sources
Source location E
E w/ Buonicore methodology*
Upgradient
528 ft.
Downgradient
100 ft. (LNAPL)
30 ft. (dissolved)
Cross-gradient
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 A-301, Proceedings, AWMA 104th Annual Meeting in Orlando, FL, June 20–24, 2011

21. ASTM E2600-10: net reduction in AOC for Tier 1 screening of known or suspected COC sources
Source location E
E w/ Buonicore methodology*
Upgradient
1,760 ft.
Downgradient
100 ft.
Cross-gradient
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 A-301, Proceedings, AWMA 104th Annual Meeting in Orlando, FL, June 20–24, 2011.

22. EDR VEC app

23. EDR VEC app (cont.)

24. EDR VEC app (cont.)

25. ASTM E : 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

26. ASTM E2600-10: Tier 1 conclusions
A VEC exists (physical evidence)
A VEC likely exists (within close proximity, e.g., two properties?)
A VEC cannot be ruled out (further away, beyond two properties?)
VEC can be ruled out because it does not or is not likely to exist (you are done!!)

27. 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

28. 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

29. 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

30. Invasive (soil, groundwater or soil gas sampling)
ASTM E : 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

31. ASTM E2600-10: Tier 2 conclusions
VEC exists (physical evidence)
VEC likely exists (within close proximity, e.g., two properties?)
VEC cannot be ruled out (further away, beyond two properties?)
VEC can be ruled out because it does not or is not likely to exist (you are done!!)

32. 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

33. Why do we care about E2600-10 if it’s not part of a Phase I ESA?
ASTM E Section 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

34. Why do I care about E2600-10 if it’s not part of a Phase I ESA. (cont
Both ASTM E and E rely on EP’s professional judgment, so ultimately it’s still up to you
Using guidance in E does not mean you have to write a full report…

35. 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

36. Scope of work: Tier 2 Non-intrusive Intrusive sampling
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

37. Final thoughts
Not required for ASTM E , but a useful guide!