Draft Sewage Sludge Risk Assessment for Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS)

Draft Sewage Sludge Risk Assessment for Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS); Extension of Comment Period

This is a second extension of the public comment period for EPA's Draft Sewage Sludge Risk Assessment for PFOA and PFOS, originally published January 15, 2025. The comment period was first extended 30 days on February 21, 2025, and is now extended an additional 120 days in response to stakeholder requests, moving the deadline to August 14, 2025. The draft risk assessment evaluates potential risks to human health and the environment from PFOA and PFOS in sewage sludge that is land applied, surface disposed, or incinerated, and will inform future EPA regulatory actions under the Clean Water Act.

Draft Sewage Sludge Risk Assessment for Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonic Acid (PFOS)

The EPA is announcing the availability of its Draft Sewage Sludge Risk Assessment for PFOA and PFOS for a 60-day public comment period closing March 17, 2025. The draft assesses human health risks from land application, surface disposal, and incineration of sewage sludge containing these two PFAS chemicals under the Clean Water Act. Central tendency modeling finds that risk thresholds for cancer and non-cancer effects are exceeded across multiple exposure pathways, including drinking water, milk, beef, eggs, and fish, even when sewage sludge contains only 1 part per billion of PFOA or PFOS. The findings are expected to inform potential future regulation under CWA section 405.