The cleanup of the Santa Susana Field Laboratory is entering another stage of public review. California regulators have scheduled an online meeting for November 18 to discuss proposed groundwater cleanup measures in Boeing's areas of responsibility at the former research and rocket testing facility in the hills near Simi Valley.

This is a chance for residents to learn what is being proposed, understand how the different cleanup efforts fit together, and ask questions before final decisions are made.

The meeting at a glance

When: Wednesday, November 18, 2026, from 6 to 8 p.m.
Where: Online public meeting
Organizer: California Department of Toxic Substances Control (DTSC)
Topic: Boeing's Draft Groundwater Corrective Measures Study and DTSC's Draft Statement of Basis.

DTSC lists the meeting and a registration link on its official Santa Susana Field Laboratory meetings page. The agency says further information about the documents and public comment period will be posted there. Check the page for updates before the meeting.

What is the Santa Susana Field Laboratory?

The Santa Susana Field Laboratory, often called SSFL, is a roughly 2,850 acre former industrial research site in the hills southwest of Simi Valley. Rocket engine testing and nuclear research were among the activities carried out there over several decades. Investigations have identified contamination that requires cleanup and long-term regulatory oversight.

The site is divided into different areas of responsibility. That matters because Boeing, NASA and the U.S. Department of Energy are associated with distinct portions of the property and cleanup obligations. A decision about one area or environmental medium is not necessarily a decision for the entire site. DTSC maintains a site overview with project records and updates.

To see how the Field Laboratory is divided into different areas, view the Santa Susana Field Laboratory site map.

What is groundwater, and what is being considered?

Groundwater is water beneath the land surface that moves through soil and rock. At Santa Susana, evaluating groundwater contamination is complicated by fractured bedrock. Investigators study where contaminants are present, how they may move, and how different cleanup methods could reduce contamination and protect people and the environment.

For Boeing's groundwater areas, the upcoming discussion centers on two types of documents. A Corrective Measures Study (CMS) compares potential approaches to cleanup. A Draft Statement of Basis describes which approach DTSC proposes to select and why. These are parts of the regulatory decision process, not proof that a remedy has already been implemented or that cleanup has been completed.

DTSC specifically identifies Boeing's Draft Groundwater CMS and its Draft Statement of Basis as the subjects of the November 18 meeting. The agency has said the relevant material and comment instructions will be made available through its meeting information page.

How is this different from other cleanup work?

It is easy to confuse updates from different parts of Santa Susana because several cleanup processes are moving forward on separate tracks.

Boeing soil and soil vapor: DTSC held a public review in 2025 for a separate proposal covering contaminated soil, soil vapor and related surface materials in Boeing's areas of responsibility. That review is not the same as the groundwater proposal now scheduled for November. DTSC explains the earlier process on its Boeing soil and soil vapor cleanup page.

NASA groundwater: DTSC approved a separate NASA Phase 1 groundwater cleanup decision in January 2026, focused on selected areas with high concentrations of trichloroethylene, also known as TCE, and associated soil vapor and seep concerns. Further evaluation of other NASA groundwater areas is planned. You can read the NASA groundwater project documents and decision history directly from DTSC.

These distinctions matter when reading headlines about whether a particular cleanup plan has been proposed, approved or carried out.

What about local drinking water?

Finding groundwater contamination at the Field Laboratory does not, by itself, mean Simi Valley's municipal drinking water is contaminated. Groundwater at the site and water delivered to local customers involve different sources, pathways and monitoring questions. Those questions should be answered using site investigation results and the local water supplier's published water quality information, not assumptions based on the presence of contamination at the property.

The purpose of this article is to explain the upcoming regulatory process. It does not make a separate determination about drinking water safety or individual health risks.

How residents can get involved

1. Register for the November 18 meeting. DTSC provides a meeting registration link and the latest details on its official meetings page.

2. Read the supporting material. Look for the Boeing groundwater Corrective Measures Study, DTSC's Draft Statement of Basis and any public notice or fact sheet. The DTSC project updates page is another place to check for newly posted documents.

3. Confirm how and when to submit comments. Earlier planning information identified a possible November 3 through December 21, 2026 public comment window, but DTSC's meeting listing did not yet confirm those dates as of November 2. Do not rely on that range as a deadline. Use DTSC's official public notice for the verified dates, instructions and submission methods once posted.

4. Bring specific questions. Ask which contaminants and locations are covered, how the alternatives compare, what monitoring will continue, how success will be measured, and what happens if a selected approach does not perform as expected. DTSC also offers a Santa Susana community question portal.

What happens after the review?

DTSC considers comments and the supporting technical record before making its final remedy decision. Additional design, implementation, monitoring and reporting follow. These steps can take time, and a proposed cleanup method should not be confused with a finished cleanup.

Why this matters for Simi Valley

The Field Laboratory is part of our region's aerospace history, but the cleanup is an ongoing issue affecting how residents understand the land and its future. Whether you have followed it for years or are hearing about this review for the first time, the public meeting is an opportunity to get information directly from the agency responsible for oversight.

For the latest documents, registration and verified comment deadlines, start with DTSC's official Santa Susana Field Laboratory meetings page.

Information reviewed November 2, 2026. Meeting materials and participation details may change. The official DTSC notice controls.