CalEPA Vapor Intrusion Workgroup’s Public Workshop Series - Kickoff Workshop

The California Environmental Protection Agency (CalEPA) Vapor Intrusion Workgroup (CalEPA VI Workgroup) is a multi-agency workgroup consisting of the Department of Toxic Substances Control (DTSC), the State Water Resources Control Board (State Water Board), the Regional Water Quality Control Boards, and the Office of Environmental Health Hazard Assessment (OEHHA) that serves as a technical and regulatory resource for addressing contaminated sites impacted by vapor intrusion across California. The CalEPA VI Workgroup is planning a series of public workshops to gain input on CalEPA’s efforts to evaluate vapor intrusion at contaminated sites. The Kickoff Workshop will be hosted via Zoom on July 24, 2025, from 9:00 a.m.-12:00 p.m. PDT – this will be a virtual-only workshop with no physical location.

• Public Notice (July 2025)
• Aviso Público (July 2025)
• VI Public Workshop Kickoff Commentor Summary
• VI Public Kickoff Workshop recording (CalEPA Vapor Intrusion Public Workshop Kickoff - July 24, 2025)

CalEPA Vapor Intrusion Workgroup's 2026 Public Workshop Series:

Vapor Intrusion: The Complete Picture from Fundamentals to Redevelopment - Working Together

The California Environmental Protection Agency (CalEPA) Vapor Intrusion Workgroup (CalEPA VI Workgroup or Workgroup) is pleased to host five virtual public workshops in the first half of 2026 to share and gain input on CalEPA's efforts to address vapor intrusion (VI) at contaminated sites. At the July 24, 2025, Kickoff Workshop, the Workgroup provided updates on CalEPA's VI strategies and gathered public feedback to inform the future workshop series. Since July, the Workgroup has been reviewing and incorporating feedback from the Kickoff Workshop into the upcoming 2026 series.

The five upcoming workshops will feature introductory training on vapor intrusion, a deep dive into vapor intrusion in the community and collaborative engagement, along with technical presentations and discussions on the holistic approach and tools to manage VI sites effectively, including conceptual site models, paths to closure, collective decision-making, and VI data in GeoTracker and EnviroStor.

2026 VI Workshop Series (final dates are subject to change):

1. Vapor Intrusion Cleanup Case Basics Training – Feb 12, 2026
2. Vapor Intrusion in the Community – Feb 25, 2026
3. Vapor Intrusion Holistic Approach Part 1: Conceptual Site Model and Best Practices – March 10, 2026
4. Vapor Intrusion Holistic Approach Part 2: Conceptual Site Model to Paths to Closure and Collective Decision-Making – May 2026
5. Vapor Intrusion Data – June 2026

Prior to each workshop, public notices with registration information will be shared through email subscription lists and posted on the Department of Toxic Substances Control's (DTSC) and the State Water Resources Control Board's (State Water Board) websites. For more information or questions, please contact us at: dwq-vaporintrusion@waterboards.ca.gov.

Background

The CalEPA VI Workgroup is a multi-agency workgroup consisting of the DTSC, the State Water Board, multiple Regional Water Quality Control Boards, and the Office of Environmental Health Hazard Assessment (OEHHA) that serves as a technical and regulatory resource for addressing contaminated sites impacted by vapor intrusion across California.

On July 24, 2025, the Workgroup hosted a Kickoff Workshop for the vapor intrusion workshop series to provide an update of CalEPA's key vapor intrusion evaluation tools and strategies and outline the agency's planned path forward. The Kickoff Workshop included three presentations by the Workgroup, a public panel discussion, and five concurrent, topic-specific breakout sessions. The panel discussion provided different public perspectives and viewpoints relating to the investigation, cleanup, and decision-making regarding vapor intrusion at contaminated sites. The goal of the breakout sessions was for the CalEPA VI Workgroup to gain feedback on specific vapor intrusion topics to inform and improve the content of future workshops in the series. The breakout session topics were:

1. Conceptual Site Model and Best Practices for Vapor Intrusion Sites,
2. Vapor Intrusion in the Community,
3. Path to Closure for Vapor Intrusion Sites,
4. Collective Decision-Making with Vapor Intrusion Partners, and
5. Vapor Intrusion Data in GeoTracker.

The feedback from the Kickoff Workshop and the 2026 Public Workshop Series will be considered in the CalEPA VI Workgroup's future planning and upcoming 2026 staff training sessions.