At a Gla

24-E-0023
February 29, 2024

The EPA Needs to Determine Whether Seresto Pet Collars Pose an
Unreasonable Risk to Pet Health

Why We Did This Evaluation

To accomplish this objective:

The U.S. Environmental Protection
Agency Office of Inspector General
conducted this evaluation to determine
whether the (1) EPA's response to
reported pesticide incidents involving
Seresto pet collars provides assurance
that the collars can still be used without
posing unreasonable adverse effects to
human health and the environment and
(2) EPA adhered to pesticide
registration requirements in its approval
of Seresto pet collars, specifically
toxicological data requirements in
40 C.F.R. part 158. This evaluation is
the result of multiple OIG Hotline
complaints.

As of August 2023, the EPA was
reviewing the active ingredients,
flumethrin and imidacloprid, in Seresto
pet collars, pursuant to Federal
Insecticide, Fungicide, and Rodenticide
Act requirements. The Act mandates
that the EPA determine whether a
pesticide "will not generally cause
unreasonable adverse effects on the
environment."

To support this EPA mission-related
effort:

•	Ensuring the safety of chemicals.

To address this top EPA
management challenge:

•	Safeguarding the use and disposal
of chemicals.

What We Found

The EPA's response to reported pesticide incidents involving Seresto pet collars has not
provided assurance that they can be used without posing unreasonable adverse effects to
the environment, including pets. While the EPA's Office of Pesticide Programs adhered to
the toxicological data requirements in 40 C.F.R. part 158 in its initial approval of Seresto
pet collars, it has not adhered to the pesticide registration review process for the active
ingredients flumethrin and imidacloprid in the Seresto pet collars. The Office of Pesticide
Programs did not conduct or publish domestic animal risk assessments, which it had
committed to doing in the work plans for these two pesticides; continues to use an
inadequate 1998 companion animal safety study (Guideline 870.7200); and lacks standard
operating procedures and a measurable standard to help determine when domestic animal
pesticide products pose unreasonable adverse effects to the environment, as required by
the Federal Insecticide, Fungicide, and Rodenticide Act.

Additionally, the EPA's Pesticide Incident Reporting System and reporting process do not
capture adequate data that the EPA needs to assess unreasonable adverse effects of pet
products. The EPA requested that current and former Seresto pet collar registrants provide
more than the required aggregate reporting of pet incident data because of the Agency's
concerns about the numerous reports of adverse incidents it had received. In July 2023, the
EPA reported that it completed a review of Seresto pet collar-related incident reports and
said that, in many of the death-related incidents, critical details were missing, preventing
the Agency from determining the cause of the deaths. The EPA worked with the current
Seresto product registrant to take measures, and the EPA limited its approval of Seresto
pet collar registrations to five years. While the EPA will continue to evaluate Seresto
incidents over that period, the Office of Pesticide Programs needs to prioritize several
areas for improvement to ensure that pesticide products do not pose unreasonable adverse
effects to pets.

Pet collars containing pesticides continue to be used without
assurance that there are no unreasonable adverse effects on
the environment, including pets.

Recommendations and Planned Agency Corrective Actions

We make eight recommendations to assist the EPA in determining whether Seresto pet
collars can be used without posing unreasonable adverse effects in pets. The EPA
generally agreed with Recommendations 2, 3, 5, 6, 7, and 8, which are resolved with
corrective actions pending. Recommendation 4 is also resolved with corrective actions
completed. The EPA did not agree with Recommendation 1, which remains unresolved.

Address inquiries to our public
affairs office at (202) 566-2391 or
OIG.PublicAffairs@epa.gov.

List of OIG reports.


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