The Final Draft Supplemental Guidance for Screening and Evaluating Vapor Intrusion released by the Cal/EPA was released today formalizing the use of a generic attenuation factor of 0.03 for screening vapor intrusion. Significant research has shown that this attenuation factor is not representative of conditions observed in California.
For example, the June 2021 California Specific Attenuation Factor study presented by Lahvis et. al found that the use of a 0.03 attenuation factor resulted in over-predictions of vapor intrusion risk at many sites in California. Similarly, a study recently released by the California Department of Toxic Substances Control (DTSC) also found that the use of a 0.03 attenuation factor may not be appropriate in some cases and instead presented an empirical attenuation factor of 0.0009.
Despite these findings, the Cal/EPA has decided to maintain the 0.03 attenuation factor as a conservative approach. This conservatism continues to create significant barriers for redevelopment and economic growth, as many properties are being flagged for potential vapor intrusion risks that are unlikely to exist.
At Path Forward, we are at the forefront of understanding the latest research and regulatory guidance on this issue. We can work with our clients to evaluate their properties using site-specific information and advanced modeling techniques to ensure that vapor intrusion risks are accurately identified and managed.
With our strong relationships with regulatory agencies, we can also help our clients navigate the complex regulatory landscape and keep their projects moving forward. Whether it’s assessing potential vapor intrusion risks or developing mitigation strategies, Path Forward is here to help our clients achieve their goals while protecting public health and the environment.
For more information about Path Forward’s Vapor Intrusion Services, please visit: https://www.pathfw.net/contaminated-sites/vapor-intrusion-assessments/
#vapor intrusion #attenuation factor #vapor intrusion assessments #environmental consulting #contamination