DPR to Issue Aquatic Risk Memo for Pet Flea-Control Products

DPR is accepting public comments on a Draft Aquatic Risk Memorandum for pet flea-treatment products containing the insecticide fipronil.

The draft memo is based on DPR studies that have found drainage of these products into sewer systems can harm aquatic life when treated water is released into waterways.

DPR relied on modeling analyses to evaluate the aquatic risk posed by these topical fipronil products, such as spot-on and spray products for dogs and cats. Scientists also used monitoring data from California wastewater treatment facilities.

DPR is accepting public comments on the study and possible mitigation options for 60 days – from Dec. 19, 2025, through Feb. 16, 2026. Feedback can be submitted via DPR’s online public comment portal.

DPR’s studies and this memo are part of the department’s continuous evaluation process that analyzes new information on registered pesticides for potential environmental or human health impacts and informs future actions including regulatory changes, label changes or other mitigation.