Products intended to kill fleas and ticks can also poison pets and the people who handle them.

The simple truth, however, is that the poisons in many of these products are not safe, either for pets or humans. Government regulation of these products has been sketchy, and testing of their impact in the home has been inadequate. The result is that many of the products sold by the millions in grocery, drug and pet supply stores, even when applied as instructed on the box, can cause serious health consequences to pets and humans.

The main culprits are products that rely on a family of chemicals called organophosphates. One of these, tetrachlorvinphos, is still found in stores. Six others were removed from the market, one by one, from 2000 through 2006: chlorpyrifos, dichlorvos, phosmet, naled, diazinon and malathion. Many pet owners may still have leftover supplies of products containing these chemicals in their homes. They were used in brands marketed under a variety of names. Another family of chemicals, called carbamates, is also of potential concern. The two most common carbamate chemicals used in pet products are called carbaryl and propoxur. For a list of pet products and the chemicals they contain, check out NRDC's Green Paws Product Guide.

Organophosphates and carbamates work by interfering with the transmission of nerve signals. Since the chemical process they attack is common to insects, humans, dogs and cats, they harm more than just fleas and ticks. Indeed, thousands of acute toxic poisonings have been logged at poison control centers across the United States. Moreover, evidence suggests the possibility of worrisome long-term effects for children exposed to these products at an early age, including later-in-life cancer and perhaps Parkinson's disease.

Children, and particularly toddlers, are especially vulnerable for two reasons. First, their nervous systems are still developing, so the organophosphates can do greater and more lasting damage. Second, children's normal behavior brings them in close contact with their pets, and therefore to any poisons applied to those pets. In particular, toddlers' hand-to-mouth tendencies make it easy for toxics to be ingested, and not just by petting the family dog and then putting their hands in their mouths. Because children spend their time where the toxics from pet products tend to accumulate -- crawling on rugs, playing with pet toys, touching accumulations of household dust, and more -- they are likely to come in contact with these poisons even when they do not touch their pet.

As bad as these products may be for pet owners and caregivers, they often are worse for the pets themselves. Based on the very limited data available, it appears that hundreds and probably thousands of pets have been injured or killed through exposure to pet products containing pesticides. As with small children, pets cannot report when they're being poisoned at low doses.

Healthier alternatives to these pesticides are readily available. Easy physical measures like frequent bathing and combing of pets can make the use of pesticides unnecessary. Learn about other chemical-free flea and tick treatments on NRDC's Green Paws site.

The threat posed to humans and pets by the poisons in commonly available products is intolerable and unnecessary. With that in mind, the Natural Resources Defense Council has filed a lawsuit against 16 retailers and manufacturers in the state of California for selling pet products containing propoxur without proper warning labels. According to the state's Safe Drinking Water and Toxic Enforcement Act, known as Proposition 65, businesses are prohibited from exposing consumers to any chemical "known to the state to cause cancer or reproductive harm" without proper warning. Through a petition, NRDC is also calling on the EPA to immediately ban the use of tetrachlorvinphos and propoxur pet pesticides and to take steps to better inform veterinarians, pet owners and the general public about safer alternatives for the control of fleas and ticks on pets. NRDC conducted a first-of-its-kind study on the hazards of pesticide residue from flea and tick collars and found that those from tetrachlorvinphos and propoxur were high enough to pose serious neurological and cancer risks to children and adults who play with their pets. Some residue levels were so high that the risk they pose to children was up to 1,000 times higher than the EPA's acceptable levels. These alarming results demonstrate a significant problem that the EPA can remedy by immediately banning tetrachloryinphos and propoxur from pet products. You can read all of the study's findings in the resulting report, Poison on Pets II: Toxic Chemical in Flea and Tick Collars.

What Pet Owners Can Do

In the meantime, pet owners can protect their families and their pets with some simple steps.

First, pet owners should begin using safer products on their pets, avoiding products that contain hazardous chemicals. Specifically, consumers should avoid products that list tetrachlorvinphos, carbaryl and propoxur. You can find a complete list of harmful chemicals and their risk factors on in the Green Paws Product Guide.

In many cases, fleas and ticks can be controlled with simple measures, such as brushing pets regularly with a flea comb while inspecting for fleas, vacuuming, and mowing frequently in areas where pets spend the most time outdoors. If you must resort other measures, flea control in pill form (such as lufenuron, nitenpyram, or spinosad) is safer than anything that leaves a residue on the fur. If you want to choose a topically applied product, check the labels for the names S-methoprene or pyriproxyfen, as these are safer alternatives. The other options for tick treatment are less-than-ideal. There are currently no truly safe pesticides that are effective against ticks. Many people use fipronil (Frontline) or selamectin (Revolution) as first choices. Other options, such as permethrin, pyrethrins, or imidacloprid are also effective, although the former two chemicals should be avoided in cats. Because these tick treatments are all applied topically, they can leave a residue on your pet's fur. Remember to wash your hands (and your kids' hands) after petting your dog or cat, and preferably avoid sleeping with your pet when they have these treatments on their fur.

In particular, pregnant women and families with children should stop using organophosphate- or carbamate-based products immediately. Finally, children should never be allowed to apply flea shampoos, dusts, dips, etc. to their pets. The unfortunate truth is that the EPA has overlooked and underestimated the particular risks to children when evaluating the safety of these products for home use. If you think you or your pet has been affected by a pet product containing pesticides, call your local poison control center if you need immediate help, and report the incident to the EPA's National Pesticide Telecommunications Network, at (800) 858-7378.


NRDC - NATURAL RESOURCES DEFENSE COUNCIL