When most pet owners adorn their dogs or cats with flea collars, they assume the chemicals have been tested for safety. But that’s not always the case. According to a report just released by the Natural Resources Defense Council (NRDC), many name-brand collars on store shelves contain chemicals that can harm pets and their owners, and the U.S. Environmental Protection Agency (EPA) isn’t doing anything to stop them.
The report honed in on two particular chemicals, tetrachlorvinphos (TCVP) and propoxur, used on national brands of flea collars, including Hartz and Zodiac. TCVP belongs to the class of nerve-damaging chemicals known as organophosphates, most of which are so hazardous that they’ve been banned for residential use or for use on pets. Propoxur belongs to a class of chemicals called carbamates, which also cause nerve damage, and it’s on California’s Proposition 65 list of chemicals known to cause cancer. NRDC was particularly concerned with exposure among toddlers and children, who pet animals and then put their hands in their mouths.
Both classes of pesticides have come under scrutiny in other indoor and outdoor uses. But, says Gina Solomon, MD, senior scientist at NRDC and lead author of the report, “When we took a look at the EPA’s files for these chemicals, we were stunned to discover that, after making decision to leave them on the market, they had no scientific data on which to base their decision. The fact that the EPA hadn’t bothered to see how much residue would end up on fur was a big surprise.”
THE DETAILS: For two weeks, volunteers allowed the NRDC scientists to outfit 10 dogs and cats with flea collars containing these two chemicals. They tested the animals’ fur 3 days after the start of the experiment and again at the end of the 14-day period. After 3 days, 60 percent of the dogs wearing TCVP-treated collars and 100 percent of the dogs wearing the propoxur-treated collars had levels of chemicals on their fur that exceeded the EPA’s recommendations for toddler-age exposure; 100 percent of the cats wearing TCVP collars had similar high levels of residues. The levels of TCVP on fur dropped off significantly after 14 days, but the levels of propoxur remained high. Seventy-five percent of the dogs still had unsafe levels of the chemical on their fur.
WHAT IT MEANS: It’s unlikely that a single exposure to these collars will give you or your toddler cancer, but why take chances on long-term exposure? “For an individual, the risk is pretty small, but if you multiply the risk across the numbers of people who touch these collars, the number is disturbing,” says Dr. Solomon. They estimate that chemical residues from these collars could lead to a risk of 56 to 558 excess cancers per million people exposed. “We really want people to reduce exposures because they’re not necessary,” Dr. Solomon adds. And the collars may not even be effective. She notes that her dog, who was a willing study participant, rarely got fleas before using the collars but, during use, contracted a bad case of fleas near his rump.