Synergist - April 2010

Action” (NFA) letter—have had their NFA reversed if the original investigation did not assess VI potential. These sites may face new requirements for VI investigation if the site contaminants and conditions represent a risk for VI exposure. The additional VI investigation often triggers the discovery of off-site impacts and a potential third-party claim.

Notable litigation cases include the Redfield, Colo., Department of Transportation and Brown Retail sites. Although the contaminated groundwater plume at these sites had been reportedly delineated, the vapor plume was found (via direct indoor air sampling) to extend more than two miles from the source areas. Local residents filed a $380 million civil action for property diminution in value (DIV) because of the required installation of VI mitigation systems in their homes. However, after a real estate market analysis indicated no difference in appraisal value at that time between houses with and without mitigation systems, the amount awarded to the neighborhood residents was significantly reduced. This noteworthy case demonstrates the need for a careful communication plan with the local community and the difficulty in proving a claim for DIV based on VI exposure.

Table 2. Comparison of Non-Residential Indoor Air Screening Levels to Occupational Exposure Limits (µg/m3)

California North Carolina

Benzene

0.14

1.6

PCE

0.693

2.1

TCE

2.04

6.1

New Jersey

2

3

Pennsylvania

11

29

0.72

OSHA PEL

3250

689,000

546,000

Table 3. ASTM Standard E2600-08 for Vapor Intrusion Assessment

Tier
Guidance
Tier 1: Screening for potential
vapor intrusion condition (pVIC)

Search distance test Chemicals of concern test

Tier 2: Screening using site-specific data

Non-invasive-plume test/critical distance determination or risk-based concentration test Invasive—soil gas and groundwater sampling

Tier 3: Informational

Toolbox of approaches–follow appropriate/ applicable government guidance and regulation

Tier 4: Informational

Identifies general mitigation alternatives

Indoor air sampling is the most direct method of determining whether the vapor intrusion pathway is complete and whether building occupants face a long-term health risk.

jury’s sympathy for the ill child resulted in a multi-million dollar award.

The subject of VI is a moving target. States continue to issue VI guidance, although no national consensus exists on sampling techniques, analytical methods, and, more importantly, screening levels. VI represents a real liability to site owners based on potential significant costs for required VI investigations, on- or off-site VI mitigation system installations, and potential third-party claims based on DIV or exposure-related bodily injury.

Recent bodily injury claims due to exposure to contaminant vapors have presented significant legal defense challenges. In City of San Antonio v. Pollock, a young child’s leukemia diagnosis was allegedly the result of in utero exposure to contaminant vapors emanating from the adjacent landfill and entering the Pollock home. Even though the plaintiff’s experts were not able to demonstrate a cause-and-effect relationship between the vapor exposure and the disease, the

To learn more about the role of industrial hygienists in VI investigations, see Parts I and II of “Vapor Intrusion: Environmental and IAQ Challenge” in the February and April 2007 issues of The Synergist.

Michelle Gillie, CIH, CPEA, is with Tetra Tech/ GeoTransInc.inKingofPrussia, Pa.Sheisamember of the VI subcommittee of the AIHA Environmental IssuesCommittee.Shecanbereachedat(610)337- 7660 or mgillie@geotransinc.com.

Sandra Gaurin, ERM, LEED AP, is with Tetra Tech Rockaway, N.J.Sheisamemberof theInterstateTechnology&Regulatory Council’s Vapor Intrusion group.

Resources American Petroleum Institute: Publication 4741, “A Practical Strategy for Assessing the Subsurface Vapor-to-Indoor Air Migration Pathway at Petroleum Hydrocarbon Sites.” November 2005.

U.S. Department of Defense: Vapor Intrusion Handbook, prepared by the Tri-Service Environmental Risk Assessment Workgroup. January 2009.

EPA: “Brownfields Technology Primer: Vapor Intrusion Considerations for Redevelopment.” EPA 542-R-08-001. [Online] Available at www.brownfieldstsc.org. March 2008.

EPA: Vapor Intrusion Database. [Online] Available at http://iavi.rti.org.

EPA: Indoor Air Vapor Intrusion Mitigation Approach. [Online] Available at www.epa.gov/ nrmrl/pubs/600r08115/600r08115.pdf.

Interstate Technology & Regulatory Council: Technical and regulatory guidance supplement: “Vapor Intrusion Pathway: Investigative Approaches for Typical Scenarios” (ITRC VI-1A, 2007).