Americans spend more than $1 billion each year on products designed to kill fleas and ticks on household pets, especially dogs and cats. 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. The April 2009 paper Poison on Pets II details a first-of-its-kind study by NRDC showing 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.