Regulation at the State-Level: Updates
(Read the first in this blog series here)
In recent months, several U.S. states have made significant progress in updating their vapor intrusion guidance and regulatory frameworks, signaling a continued shift toward a more science-driven and health-protective approach.
The Oregon Department of Environmental Quality (DEQ) released a draft update to its vapor intrusion guidance—the first major revision since 2010—which was open for public comment through June 30, 2024. The proposed changes align Oregon’s screening levels with the EPA’s updated attenuation factors, eliminates reliance on soil-based screening for risk evaluations, and emphasizes the use of high-quality sub-slab and soil gas data in decision-making. The final version is anticipated later this year, following additional review and stakeholder input. [source].
The California Environmental Protection Agency (CalEPA) Vapor Intrusion Workgroup "Supplemental Guidance" was released as a final draft in February 2023. The guidance reinforces a multiple-lines-of-evidence approach and upholds the use of EPA’s conservative attenuation factor of 0.03 for groundwater-to-indoor air pathways, while providing additional tools for site-specific evaluations and decision-making. [source, source].
New York State’s Department of Health (NYSDOH) also advanced its regulatory approach in February 2024 by updating its Guidance for Evaluating Soil Vapor Intrusion. The revised matrices now include 13 additional petroleum-related volatile organic compounds (VOCs), such as benzene, toluene, ethylbenzene, and xylenes (BTEX), which broadens the scope of contaminants subject to monitoring and mitigation requirements [source].
Michigan’s Department of Environment, Great Lakes, and Energy (EGLE) initiated a public comment period in early 2025 for Volume 5 of its Vapor Intrusion Assessment and Mitigation Technical Guidance. This volume focuses on design and implementation considerations for both active and passive mitigation systems, reflecting a growing emphasis on engineering controls to protect building occupants [source.]
In North Carolina, the Department of Environmental Quality (DEQ) released a November 2024 update to the broader 'Guidelines for Assessment and Cleanup of Contaminated Sites, ' which includes expanded sections on vapor and risk-based cleanup levels. Among the updates, the document expanded the remediation goals and standards section to include vapor and emphasize the use of calculating risk-based cleanup levels, and outline reporting requirements. [source, source].
Collectively, these updates reflect a nationwide movement toward more stringent and technically robust vapor intrusion policies. But there is still work to do.
AVIP
The Association of Vapor Intrusion Professionals (AVIP) provides another excellent resource for any changes or updates to VI regulation and policy. The association recently published technical guidance regarding the design, implementation, and OM&M of vapor intrusion mitigation systems. Titled the “Vapor Intrusion Best Practices Roadmap,” it was created to be a best practices guide for consultants, design professionals, owners, regulators and other interested parties. It offers guidelines for developing an appropriate Vapor Intrusion Mitigation System (VIMS) design for a new or existing building to provide safe indoor air conditions for human occupancy. Additionally, AVIP hosts an annual conference where attendees can learn about the current state of the VI trends and best practices. [source]
EPRO Solutions for Vapor Intrusion Mitigation
EPRO offers a suite of high-performance vapor intrusion mitigation solutions. The Geo-Seal® line of products offer scalable protection for high and low-risk sites, and even those where a preemptive barrier can be ideal.
Geo-Seal EV40s and EV20 (we highlight both in this blog post, aptly titled “The EV Twins”) provide single sheet membrane vapor intrusion protection. Geo-Seal 100 and 60 are composite barrier systems designed for higher risk sites. And Geo-Seal EFC is an epoxy coating that can mitigate vapor intrusion risk and provide little disruption to building occupants in existing structures with contaminant vapors.
By understanding emerging trends, staying informed about regulations, and selecting proven products like those from EPRO, project teams can deliver safer, more resilient buildings that meet both performance and sustainability goals.