After 16 months of investigating, the House Subcommittee on Economic and Consumer Policy โ part of the House Oversight Committee, the main investigative body in the U.S. House of Representatives โ unfurled Wednesday its finding into the popular Seresto flea and tick collars and the Environmental Protection Agencyโs role in regulating the collars. The collars work by slowly releasing two pesticides into pets’ fur to ward off fleas and ticks.
Elanco, the collarsโ manufacturer, has maintained over the course of Investigate Midwest and USA TODAYโs reporting that the collars are safe. During a hearing Wednesday, Elancoโs president and CEO reiterated that point. (Read Elancoโs full statement here.)
Here are five important takeaways from the subcommittee’s investigation.
Seresto collars have health warnings in other countries but not the U.S. Germanyโs label notes the collar poses neurological risks, and Colombiaโs label calls it highly toxic. Australiaโs label contains the warning: โPOISON.โ Canada doesnโt even allow the collar to be sold.
Serestoโs first owner, Bayer, declined to update the U.S. label after updating Germanyโs to note neurological risks to pets. Bayer owned Serestoโs production before Elanco purchased the companyโs animal health division in 2020. The year before, the EPA asked Bayer to update the logo to reflect the one in Germany, which noted the collarโs neurological risks to pets. Bayer said the data didnโt support a label change.
Canada found incident rates involving the collars were high. In 2015, Canadian health officials examined the collars and found Seresto had an incident rate of 36 to 65 incidents per 10,000 collars sold, including three to five โdeath and majorโ incidents. The other collars in Canada at the time of the analysis had an incident rate of 0.07 per 10,000 collars sold.
The EPA confirmed Canadaโs findings, and then some. After the EPA received Canadaโs analysis, it performed its own. Canadian officials had studied 251 pet deaths linked to the collars and determined 84 of them, or 33%, were โprobably or possiblyโ caused by the collar. The EPA found that 113, or 45%, were โprobably or possiblyโ caused by the collar.
Elanco told the EPA its collar has only been linked to 12 probable or possible pet deaths. As of summer 2021, Elanco was aware of more than 2,300 pet deaths that were linked to the Seresto collars. Its own studies found that just 0.51% were โprobably or possiblyโ caused by the collar.
Top image: Subcommittee Chairman Rep. Raja Krishnamoorthi (D – Illinois) speaks at the June 15, 2022, hearing. He led the subcommittee’s investigation into Seresto.









