New Tool Validated for Vapor Intrusion Litigation:
Stable Isotope Fingerprinting
The increased regulatory focus on vapor intrusion has led to the development of better tools for determining the source(s) of VOCs in indoor air. One such tool is compound specific isotope analysis (CSIA). CSIA is a well-established method for fingerprinting of pure chemicals and groundwater contamination. CSIA compares molecular structures between two samples of the same material in order to determine the likelihood that they originated from the same source. While this approach has been applied to VOCs in indoor air, there has been some hesitation to use it in a litigation context given the lack of an established methodology. However, in the last month or so, two major developments have occurred that pave the way for utilizing this methodology for litigation related to vapor intrusion source attribution.
This presentation will provide an overview of typically vapor intrusion source attribution issues, then review and discuss the lessons learned and implication from:
- The 9th Circuit court, in City of Pomona v. SQM North America Corporation, issued 5/2/14, which held that stable isotope analysis (for perchlorate in this case) meets the Daubert standard for admissibility.
- The US Department of Defense’s environmental technology demonstration and validation program, ESTCP, issued a report titled “Use of Compound-Specific Stable Isotope Analysis to Distinguish between Vapor Intrusion and Indoor Sources of VOCs”.
These developments facilitate the use of isotope analysis techniques that can be effectively and efficiently employed to reduce uncertainty and answer questions that otherwise would be extremely difficult and costly to address.