The EPA said it will develop stricter testing and evaluation requirements for flea and tick treatments that are applied to a pet's skin. The agency also will begin reviewing labels to determine which ones need to say more clearly how to use the products.
The EPA's effort follows increasing complaints from pet owners that the "spot-on" products have triggered reactions in dogs and cats, ranging from skin irritation to neurological problems to deaths. Cats and small dogs appear particularly vulnerable, the EPA said, especially when given products intended for larger animals.
Steve Owens, assistant administrator of EPA's Office of Prevention, Pesticides and Toxic Substances, said new restrictions will be placed on flea and tick products, with additional changes for specific products likely - including possible changes in some product formulas.
"These are poisons," Owens said. "These are products designed to kill fleas and ticks - and they do their jobs."
The EPA is committed to better protecting the health and safety of pets and families, Owens said, but added that pet owners "need to carefully read and follow all labeling before exposing your pet to a pesticide."
The agency announced last April it was increasing scrutiny of topical flea and tick products because of the growing number of bad reactions reported.
The EPA said it received 44,263 reports of harmful reactions associated with topical flea and tick products in 2008, up from 28,895 in 2007. Reactions ranged from skin irritations to vomiting to seizures to, in about 600 cases, death of an animal.
An EPA spokesman said he did not have a breakdown of how many deaths were dogs and how many cats.
Dog and cat owners say their pets have suffered burns and welts on their skin; started to drool excessively; begun to shake uncontrollably; lost control of their legs or experienced other neurological problems after using the flea and tick treatments.
A 2009 study by the American Society for the Prevention of Cruelty to Animals reported that the majority of illnesses linked to proper use of topical flea and tick products were mild. Cats were more susceptible than dogs to illnesses and deaths from misuse of the products, the report said.
"The important take-home message is that although adverse reactions can occur with all flea and tick products, most effects are relatively mild and include skin irritation and stomach upset," said Dr. Steven Hansen, ASPCA veterinary toxicologist and senior vice president for animal health services.
Pet owners should keep using the products as directed when faced with a flea infestation, Hansen said.
Georgia-based Merial Ltd., which makes the popular Frontline tick and flea treatment, defended its product and disputed the EPA data.
"The number of adverse events reported for Frontline has remained consistently low since the product's introduction in 1996," the company said in a statement e-mailed to reporters. The vast majority of reactions are minor, the statement said.
In a 29-page report, the EPA said the majority of problems for dogs occurred in smaller dogs, weighing 10 to 20 pounds. Some incidents occurred when products intended for larger dogs were given to smaller animals, the report said. Chihuahuas, Shih Tzus, miniature poodles, Pomeranians and dachshunds were among breeds where problems occurred the most, the EPA said.
Similarly, many problems for cats occurred when they were given treatments intended for dogs. The EPA is likely to require companies to revamp labels to clarify that products intended for dogs should never be used on cats, Owens said.