This Fact Sheet is provided to clarify the information regarding Plutonium-239 (Pu-239) that was detected in an air sample at the former Hunters Point Naval Shipyard (HPNS).

In March 2025, it was reported to the Navy that one ambient air sample collected in November 2024, at a downwind air monitoring location in Parcel C measured Plutonium-239 (Pu-239) at 8.16 x 10-15 microcuries per milliliter (μCi/mL), above the project action level of 4 x 10-15 μCi/mL. Exceeding the project’s regulatory action level does not represent a risk to workers or the public. Regulatory action levels are deliberately and conservatively established below levels of health concern to ensure action is taken onsite by the contractor before any impact to human health can occur. The Pu-239 result was a single outlier that could not be reproduced. The Navy has taken more than 200 air samples since July 2023, and this outlier result is the only detection of Pu-239 to date. For more information, download the Fact Sheet: click this link.

The Navy is committed to transparent communication of our cleanup efforts, and we routinely provide updates with the public, City of San Francisco, and regulatory agencies as information is available. A copy of a response letter from Navy to the San Francisco Department of Public Health can be found here.