Americans spend more than $1 billion each year on products designed to kill
fleas and ticks on household pets, especially dogs and cats.1 While some of
these products are safe, others leave harmful chemical residues on our pets’
fur and in our homes. These chemicals are highly hazardous to animals and humans, can damage the brain and nervous system, and cause cancer.
In spite of the known adverse effects of these pesticides on children, and although there are safer alternatives available, both tetrachlorvinphos and propoxur are still legal for sale to consumers to control fleas on pets. As relatively inexpensive flea control options, they remain on the shelves and many consumers are unaware of the dangers posed by these
Children Are Most Vulnerable to Flea Collar Poisoning
A first-of-its-kind study by NRDC shows that high levels of pesticide residue can remain on a dog’s or cat’s fur for weeks after a flea collar is put on an animal. Residue levels produced by some flea collars are so high that they pose a risk of cancer and damage to the neurological system of children up to 1,000 times higher than the EPA’s acceptable levels.
Children are particularly at risk from these pesticides because their neurological and metabolic systems are still developing. They are also more likely than adults to put their hands in their mouths after petting an animal, and so are more likely to ingest the hazardous residues. We found that residues from two pesticides used in flea collars—tetrachlorvinphos and propoxur, among the most dangerous pesticides still legally on the market—were high enough to pose a risk to both children and adults who play with their pets.
Keep Your Pets and Family Safe and Flea-Free
1. Avoid using flea control products with dangerous pesticides by giving your pet regular baths with a pesticidefree pet shampoo, and using a flea comb between baths. Launder your pet’s bedding in hot water and vacuum
carpets regularly to eliminate flea eggs that could be hidden there.
2. If you do need to use a chemical flea control product, the safest options are generally those dispensed as a pill.
These usually contain the least toxic chemicals, and better still they don’t leave a residue on your pet or in your
3. Check the label. If you do need to buy an off-the-shelf flea and tick product, avoid flea collars that list tetrachlorvinphos or propoxur as active ingredients. Other products to avoid include permethrin-based products, and tick-control products containing amitraz. Instead, opt for products whose labels list lufenuron,
spinosad, methoprene, or pyriproxyfen. These are common and effective insect growth regulators.
4. Visit greenpaws.org for a comprehensive list of brand-name products with their chemical ingredients and more information about health risks from pesticides.
Flea and Tick Collars Contain Dangerous Chemicals
Two dangerous pesticides—tetrachlorvinphos and propoxur—are common ingredients in flea and tick collars:
Tetrachlorvinphos (TCVP) is an organophosphate pesticide and is toxic to the nervous system. Young children
are particularly susceptible because their brains are still developing, and their ability to metabolize these chemicals is
impaired relative to adults. In addition, TCVP is designated by EPA as a likely human carcinogen.
Propoxur is a chemical in the N-methyl carbamate class of insecticides, which is closely related to the organophosphates.
In addition to its neurological toxicity, propoxur is a known human carcinogen. In August 2006, California added it to a
list of chemicals known to the state to cause cancer.
Both tetrachlorvinphos and propoxur interfere with an essential enzyme (acetylcholinesterase) that normally controls
messaging between nerve cells. The result of exposure is spasmodic overexcitation of the nervous system; this is the
mechanism by which fleas and ticks are killed. In large doses, these chemicals can also harm or kill cats, dogs, and in
extreme poisoning cases even humans. More commonly, at lower levels of exposure, these chemicals cause a variety of
poisoning symptoms, many of which can mimic common illnesses; these include nausea, vomiting, diarrhea, wheezing,
sweating, and tearing eyes. More severe poisoning can cause muscle twitching, drooling, seizures, respiratory paralysis,
and death. Some recent research indicates that exposure to this type of pesticide can impair children’s neurological
development, resulting in pervasive disorders that may include delays in motor development and attention deficit/