DPR Issues Final Aquatic Risk Memo for Pet Products and Responses to Public Comment

The Department of Pesticide Regulation (DPR) is releasing the final Aquatic Risk Memo for pet flea‑and tick-control products containing fipronil, along with a Summary of Public Comments and Responses received on the December 2025 draft memo.

The memo presents DPR’s evaluation of how fipronil from pet products can reach wastewater and potentially affect aquatic life, and includes updates based on public comments received and additional analysis.

DPR is also publishing a document that responds to the public comments received on the draft memo. Overall, public comments supported the technical analysis, identified a few areas for clarification or where additional analysis would be helpful and supported moving forward to explore mitigation options, including alternatives to address risks associated with pet products containing fipronil.

These documents will inform DPR’s ongoing evaluation of options to address identified risks associated with fipronil pet products. DPR will continue engaging with interested parties as it develops a mitigation scoping document and an alternative assessment document which are anticipated to be posted for public comment in Quarter 3 of 2026.

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 measures.