EPA Superfund Site

NORTON AIR FORCE BASE (LNDFLL #2)

CA | EPA ID CA4570024345

About this site’s exposure pathways: As of September 2025, the Norton Air Force Base (Landfill #2) Superfund site is considered “Insufficient Data to make a Human Exposure evaluation” (HEID) because of a newly identified exposure pathway and/or contaminant(s), more specifically, PFAS contamination in surface soil at two locations and newly identified vapor intrusion (VI) risks at sites AOC33, IRP 17, and potentially AOC4. The site was previously categorized as "Human Exposures Under Control "HEUC".

EPA uses this Human Exposure status when there is a lack of evidence to suggest that actual or reasonably anticipated human exposures are occurring and that those exposures are above acceptable risk-based levels. The planned activities to collect sufficient information to evaluate this new exposure pathway and/or contaminants(s) are the development of a Remedial Investigation to fully evaluate the extent of PFAS contamination and evaluate risk to receptors. In order to address vapor intrusion concerns, the Air Force agreed in a letter dated April 22, 2021, to "... pursue the addition of Land Use Controls (LUCs) prohibiting residential uses to protect against potential vapor intrusion via a formal Explanation of Significant Differences (ESD) for IRP Site 17 and AOC 33." EPA currently anticipates that there will be sufficient data to make a Human Exposure evaluation by September 2026 because a Remedial Investigation addressing PFAS and the LUC prohibiting residential restrictions will have been completed by then.

The Fifth Five Year Review identified some newly constructed buildings near some areas with VI risk; however, the Air Force determined that the closest building seems to be located outside the anticipated extent of vapor migration from the source area. It is unclear whether additional sampling is needed to delineate the VI risk and update the Conceptual Site Model.