(August 12, 2020) – NACWA has asked EPA to consider the risks associated with pet flea control products containing fipronil, a pesticide with high aquatic toxicity that can pass through wastewater treatment processes.

In August 5 comments on EPA’s draft risk assessment for fipronil, NACWA explained that fipronil has been found in the effluent of publicly owned treatment works (POTWs), and research has shown how the pesticide is transferred from pets to humans and surfaces. Subsequent washing of hands and clothing indoors results in discharge of fipronil to the sewer system. Topical pet products appear to be the primary source of fipronil at POTWs studied in the San Francisco Bay area.

Since POTWs cannot control domestic use of pesticides, EPA’s risk analysis and product labeling instructions are a vital part of ensuring appropriate use. EPA did not conduct a “down the drain” analysis for fipronil, as it usually does for other pesticides used indoors and on pets. NACWA requested that EPA do this evaluation for fipronil and suggested potential mitigation measures, such as evaluating alternative pet flea control products. 

NACWA supported the comments of the Bay Area Clean Water Agencies (BACWA), which has been advocating for improved consideration of pesticide impacts to POTWs. NACWA will continue to work with BACWA to address this issue.

NACWA members with questions or information about pesticide impacts should contact Cynthia Finley, NACWA’s Director of Regulatory Affairs.